Evaluation of Marfan syndrome: MR imaging versus CT

International Nuclear Information System (INIS)

Soulen, R.L.; Fishman, E.K.; Pyeritz, R.E.; Gott, V.L.; Zerhouni, E.A.

1986-01-01

Twenty-five patients with Marfan, syndrome underwent both CT and MR imaging. MR imaging were interpreted in blinded fashion and then compared with CT scans MR imaging was found to be equivalent to CT in the detection of aortic, dural, and hip abnormalities in patients not operated on. MR imaging was superior to CT in the evaluation of postoperative patients because the artifact produced by Bjork-Shirley or St. Jude valves precludes adequate evaluation of the aortic root on CT while producing only a small inferior field distortion (a ''pseudo-ventricular septal defect'') on MR imaging. The absence of radiation exposure is another major advantage of MR imaging in this relatively young population requiring serial studies. The authors conclude that MR imaging is the modality of choice for the evaluation and follow-up of patients with Marfan syndrome and offers an appropriate means of screening their kindred

CT and MRI normal findings; CT- und MRT-Normalbefunde

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Moeller, T.B.; Reif, E. [Caritas-Krankenhaus, Dillingen (Germany)

1998-07-01

This book gives answers to questions frequently heard especially from trainees and doctors not specialising in the field of radiology: Is that a normal finding? How do I decide? What are the objective criteria? The information presented is three-fold. The normal findings of the usual CT and MRI examinations are shwon with high-quality pictures serving as a reference, with inscribed important additional information on measures, angles and other criteria describing the normal conditions. These criteria are further explained and evaluated in accompanying texts which also teach the systematic approach for individual picture analysis, and include a check list of major aspects, as a didactic guide for learning. The book is primarily intended for students, radiographers, radiology trainees and doctors from other medical fields, but radiology specialists will also find useful details of help in special cases. (orig./CB) [German] Normalbefunde sind die haeufigsten Befunde ueberhaupt. Also kein Problem? Doch. Besonders Radiologen in der Ausbildung und Aerzte aus anderen Fachgebieten stellen sich immer wieder die entscheidende Frage: Ist das normal? Woran kann ich das erkennen? Wie kann ich das objektivieren? Dieses Buch leistet dreierlei: 1. Es zeigt klassische Normalbefunde der gaengigen CT- und MRT-Untersuchungen in hoher Abbildungsqualitaet als Referenz. Direkt in die Aufnahmen eingezeichnet sind wichtige Daten: Masse, Winkel und andere Kriterien des Normalen. Sie werden im Text nochmals zusammengefasst, erklaert und bewertet. 2. Es lehrt die Systematik der Bildbetrachtung - wie schaue ich mir ein Bild an, welche Strukturen betrachte ich in welcher Reihenfolge und worauf muss ich dabei besonders achten? Dies alles in Form einer uebersichtlichen Checkliste zu jeder Aufnahme. 3. Es gibt eine Befundformulierung vor, die sich wiederum an dem Schema der Bildanalyse orientiert, alle Kriterien des Normalen definiert und dadurch auch ein wichtiges didaktisches Element darstellt

CT-guided biopsies and drainage; CT-gesteuerte Punktionen und Drainagen

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Scheppers, I.; Wollschlaeger, D. [Staedtisches Klinikum Karlsruhe gGmbH, Zentralinstitut fuer Bildgebende Diagnostik, Karlsruhe (Germany)

2011-11-15

Following the implementation of computed tomography (CT) or ultrasound-guided biopsy of solid tumors and the puncture and drainage of liquid processes, the number of surgical open biopsies and curative operations for abscess drainage has declined. Such CT-guided interventions are performed in nearly every organ. Instead of aspiration biopsies, more and more core biopsies are being performed to allow histopathological evaluation and thus allowing targeted therapy. This article is intended to give a general overview of techniques, materials, indications and contraindications. Ultrasound-guided biopsies as well as large bore vacuum biopsies of the breast are not included in this review. (orig.) [German] Infolge der Durchfuehrung von bildgesteuerten Biopsien solider Raumforderungen und Punktionen mit Drainageeinlage bei liquiden Prozessen ist die Zahl chirurgischer Exzisionsbiopsien und Abszesssanierungen zurueckgegangen. Diese Eingriffe werden in nahezu allen Organgebieten durchgefuehrt. Neben den Aspirationsbiopsien werden haeufig Schneid- oder Stanzbiopsien durchgefuehrt. Nach histologischer und immunhistologischer Untersuchung der hierbei gewonnenen Proben in der Pathologie kann fruehzeitig die nachfolgende Therapie geplant werden. Der vorliegende Beitrag soll einen allgemeinen Ueberblick ueber Methoden, Materialien, Indikationen und Kontraindikationen geben. Die ultraschallgesteuerten Biopsien sowie die Vakuumsaugbiopsien im Rahmen des Mammographiescreenings werden bewusst nicht besprochen. (orig.)

Importance of SPECT/CT for knee and hip joint prostheses; Stellenwert der SPECT/CT bei Knie- und Hueftgelenkprothesen

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Strobel, K.; Steurer-Dober, I.; Huellner, M.W.; Veit-Haibach, P.; Allgayer, B. [Luzerner Kantonsspital (Switzerland). Institut fuer Nuklearmedizin und Roentgendiagnostik

2012-07-15

Complications, such as loosening or infections are common problems after hip or knee arthroplasty. If conventional X-rays are equivocal bone scintigraphy is the classical second-line imaging modality. Single photon emission computed tomography/computed tomography (SPECT/CT) offers metabolic and morphologic information in one imaging step and is becoming increasingly more available in larger hospitals. The SPECT/CT procedure is a promising method and is increasingly being used in daily routine to evaluate joint arthroplasty. The additional benefit compared with classical conventional bone scintigraphy has to be evaluated in further prospective studies. In our hospital SPECT/CT regularly gives important additional information regarding prosthetic joint complications. SPECT/CT is increasingly being used as the second step imaging standard modality if conventional X-rays are equivocal. (orig.) [German] Komplikationen wie Lockerung und Infekt stellen ein haeufiges Problem nach Hueft- und Kniegelenkprothesen dar. Wenn die konventionelle Roentgenaufnahme nicht zum Ziel fuehrt, ist die klassische konventionelle Skelettszintigraphie die am haeufigsten verwendete ''Second-line''-Bildgebung. Die ''single photon emission computed tomography''/CT (SPECT/CT) bietet metabolische und morphologische Informationen bzgl. Prothesenkomplikationen in einem Untersuchungsgang und ist zunehmend in groesseren Kliniken verfuegbar. Die SPECT/CT ist eine viel versprechende Methode und wird im klinischen Alltag bei der Evaluation von Gelenkprothesen zunehmend eingesetzt. Es sind noch mehr prospektive Studien noetig, um die Leistungsfaehigkeit und den Zusatznutzen gegenueber der klassischen Szintigraphie zu evaluieren. In unserer Klinik wird die Knochenszintigraphie bei der Abklaerung von Prothesenkomplikationen zumeist mit einer SPECT/CT kombiniert und liefert regelmaessig wichtige Zusatzinformationen. Die SPECT/CT entwickelt sich zunehmend zum Standard

Indirect MR venography: contrast medium protocols, postprocessing and combination in diagnosing pulmonary emboli with MRI; Indirekte MR-Phlebografie: Kontrastmittelprotokolle, Nachverarbeitung und Kombination mit Lungenemboliediagnostik in der MRT

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Kluge, A.; Bachmann, G. [Diagnostische Radiologie, Kerckhoff-Klinik, Bad Nauheim (Germany); Rominger, M. [Diagnostische Radiologie, Phillips-Univ. Marburg (Germany); Schoenburg, M. [Herzchirurgie, Kerckhoff-Klinik, Bad Nauheim (Germany)

2004-07-01

Purpose: Integration of MR venography in a comprehensive MR imaging protocol in patients with suspected pulmonary embolism (PE) and evaluation of contrast media dosage, timing and postprocessing for diagnostic accuracy. Materials and Methods: Fortyeight consecutive inpatients with suspected PE or deep vein thrombosis were examined by MR venography according to one of the following protocols: protocol I: MR venography only, 0.25 mmol/kg bodyweight (BW) Gadopentate dimeglumine(Gd-DTPA) as single dose, bolus timing; protocol II: MR angiography of pulmonary arteries with a cumulative dosage of 0.25 mmol/kg contrast media, modification of coil setting for MR venography without further contrast media application; protocol III: as protocol II but with 0.125 mmol/kg BW, followed by MR venography. Signal-to-noise ratio, contrast-to-noise ratio, number of definable vascular segments and image quality were evaluated. The results were compared to conventional bilateral venography. Results: All MR venography examinations were of diagnostic quality and the examination time was below 10 min. MR venography could be performed in all 48 patients comparted to 43 of 48 patients for conventional venography. Significantly more superficial and deep veins of the leg could be visualized by MR venography (94% compared to 83% for conventional venography). Sensitivity and specificity were 100% and 92%, respectively. Quality differed significantly between 0.125 mmol/kg (protocol III) and 0.25 mmol/kg Gd-DTPA (protocols I and II) while timing did not influence quality (protocol I vs. II). (orig.) [German] Ziel: Integration der MR-Phlebografie in ein umfassendes Konzept der MRT-Diagnostik bei Verdacht auf Lungenembolie (LE). Untersuchung des Einflusses von Kontrastmittelmenge, -bolusform und Verzoegerungszeit sowie der Nachverarbeitung auf die diagnostische Qualitaet von MR-Phlebografien. Material und Methode: Bei 48 konsekutiven stationaeren Patienten mit Verdacht auf Beinvenenthrombose (TVT

Spontaneous osteonecrosis of the knee joint: MR imaging before and after administration of gadopentetate-dimeglumine, comparison to CT, scintigraphy, and histology; Spontane Osteonekrose des Kniegelenkes: MRT im Vergleich zur CT, Szintigraphie und Histologie

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Lang, P. [Dept. of Radiology, Univ. of California, San Francisco, CA (United States); Grampp, S. [Dept. of Radiology, Univ. of California, San Francisco, CA (United States); Vahlensieck, M. [Dept. of Radiology, Univ. of California, San Francisco, CA (United States)]|[Radiologische Klinik, Bonn Univ. (Germany); Mauz, M. [Dept. of Radiology, Univ. of California, San Francisco, CA (United States)]|[Radiologische Klinik, Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin (Germany); Steiner, E. [Universitaetsklinik fuer Radiodiagnostik, Wien (Austria); Schwickert, H. [Dept. of Radiology, Univ. of California, San Francisco, CA (United States)]|[Radiologische Klinik, Universitaetsklinik Mainz (Germany); Gindele, A. [Dept. of Radiology, Univ. of California, San Francisco, CA (United States); Felix, R. [Radiologische Klinik, Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin (Germany); Genant, H.K. [Dept. of Radiology, Univ. of California, San Francisco, CA (United States)

1995-06-01

Eight patients with spontaneous osteonecrosis of the knee joint underwent MR imaging before and after i.v. administration of Gd-DTPA. Nuclear scintigraphy was performed in all 8 patients, three patients also had CT scans of the knee area. Histologic correlation was available in three patients. Increased radionuclide uptake was observed in all patients. In one patient, however, scintigraphy showed increased radionuclide uptake consistent with ostenecrosis only in the medial femoral condyle, while MR imaging demonstrated osteonecrosis both in the medial as well as the lateral femoral condyles. MR demonstrated areas of low signal intensity on precontrast T{sub 1}-weighted images in the femoral condyle in all patients. All these areas showed high signal intensity on T{sub 2}-weighted images. On postcontrast T{sub 1}-weighted images, signal intensity increase was either homogeneous throughout the lesion or it was seen at the periphery of the lesion in a band-like pattern. Histologically, the areas of high signal intensity on T{sub 2}-weighted and on postcontrast T{sub 1}-weighted images corresponded to granulation tissue. (orig./MG) [Deutsch] Wir untersuchten acht Patienten mit einer spontanen Osteonekrose des Kniegelenkes mit der MRT. Ein Vergleich zum szintigraphischen Befund wurde bei allen 8 Patienten und zur CT bei drei Patienten angestellt. Eine histologische Korrelation war bei drei Patienten moeglich. Bei allen 8 Patienten zeigten die T{sub 1}-gewichteten MR-Tomographien Zonen mit reduzierter Signalintensitaet in den Kondylen, waehrend die Laesionen in den T{sub 2}-gewichteten Aufnahmen eine hoehere Signalintensitaet als das normale Knochenmark hatten. Nach Gabe von Gd-DTPA war entweder eine homogene Signalerhoehung oder eine bandfoermige Signalintensitaetszunahme in der Peripherie der Laesion zu sehen. Die Zonen mit hoher Signalintensitaet in der T{sub 2}-gewichteten Aufnahme oder mit Kontrastmittelanreicherung entsprachen histologisch Granulationsgewebe an der

Hello Mr. President! Rollenspiele zwischen Hollywood und Washington

NARCIS (Netherlands)

Mehring, F.

2016-01-01

Hello Mr. President Rollenspiele zwischen Hollywood und Washington Am 8. November 2016 entscheidet sich, wer zum 58. Präsidenten der USA gewählt wird: Die ehemalige Außenministerin Hillary Clinton oder der republikanische Kandidat Donald Trump. In der heißen Phase des Wahlkampfs fällt besonders

Cardiac MR imaging: Comparison with echocardiography and dynamic CT

International Nuclear Information System (INIS)

Colletti, P.M.; Norris, S.; Raval, J.; Boswell, W.; Lee, K.; Ralls, P.; Haywood, J.; Halls, J.

1986-01-01

The authors compared gated cardiac MR imaging with two-dimensional and Doppler echocardiography and dynamic CT. Gated cardiac MR imaging (VISTA unit, 0.5 T) was performed in 55 patients with a variety of conditions. Accuracy of diagnosis was compared. CT showed arterial, valvular, and pericardial calcifications not seen on MR imaging. Many lesions were seen as well on CT as on MR imaging. Two-dimensional echocardiography was superior in demonstrating wall motion and valvular disease. MR imaging was superior in demonstrating myocardial structures

CT and MR imaging findings of sinonasal angiomatous polyps

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Zou, Jing [Department of Radiology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong (China); Man, Fengyuan [Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing (China); Deng, Kai [Department of Radiology, Qingdao No. 4 People' s Hospital, Qingdao, Shandong (China); Zheng, Yuanyuan [Department of Radiology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong (China); Hao, Dapeng, E-mail: haodp_2009@163.com [Department of Radiology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong (China); Xu, Wenjian, E-mail: cjr.xuwenjian@vip.163.com [Department of Radiology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong (China)

2014-03-15

Objective: To characterize the CT and MR imaging findings of patients with sinonasal angiomatous polyps (SAPs) and evaluate their respective clinical value in the diagnosis of SAP. Methods: CT and MR imaging findings of 15 patients with pathologically proven SAP were examined. Assessed image features included location, size, margin, attenuation, and change of the bony walls of the sinonasal cavity on CT, and signal intensity and enhancement pattern on MR. Results: On CT, the SAP was mostly isoattenuated with patches of slight hyperattenuation. Most lesions caused changes in the adjacent bone, including expansile remodeling (n = 8), defect or destruction (n = 7), and hyperostosis (n = 6). All lesions examined by MR showed heterogeneous isointense signal intensity on T1-weighted images and mixed obvious hyperintense and hypointense signal intensity with linear hypointense septum internally (n = 10), and hypointense peripheral rim on T2-weighted images (n = 10). Postcontrast MR images demonstrated areas of heterogeneous and marked enhancement with an unenhanced hypointense rim and septa (n = 7). Conclusions: CT and MR imaging have respective advantages in the diagnosis of SAP. Combined application of CT and MR examinations is necessary for patients with suspected SAP.

CT and MR imaging findings of sinonasal angiomatous polyps

International Nuclear Information System (INIS)

Zou, Jing; Man, Fengyuan; Deng, Kai; Zheng, Yuanyuan; Hao, Dapeng; Xu, Wenjian

2014-01-01

Objective: To characterize the CT and MR imaging findings of patients with sinonasal angiomatous polyps (SAPs) and evaluate their respective clinical value in the diagnosis of SAP. Methods: CT and MR imaging findings of 15 patients with pathologically proven SAP were examined. Assessed image features included location, size, margin, attenuation, and change of the bony walls of the sinonasal cavity on CT, and signal intensity and enhancement pattern on MR. Results: On CT, the SAP was mostly isoattenuated with patches of slight hyperattenuation. Most lesions caused changes in the adjacent bone, including expansile remodeling (n = 8), defect or destruction (n = 7), and hyperostosis (n = 6). All lesions examined by MR showed heterogeneous isointense signal intensity on T1-weighted images and mixed obvious hyperintense and hypointense signal intensity with linear hypointense septum internally (n = 10), and hypointense peripheral rim on T2-weighted images (n = 10). Postcontrast MR images demonstrated areas of heterogeneous and marked enhancement with an unenhanced hypointense rim and septa (n = 7). Conclusions: CT and MR imaging have respective advantages in the diagnosis of SAP. Combined application of CT and MR examinations is necessary for patients with suspected SAP

Pretherapeutic and posttherapeutic laryngeal imaging; Prae- und posttherapeutische Larynxbildgebung

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Becker, M.; Burkhardt, K.; Allal, A.S.; Dulguerov, P.; Ratib, O.; Becker, C.D. [Hopitaux Universitaires de Geneve, Abteilung fuer Hals-Nasen-Ohren-Radiologie, Geneve (Switzerland)

2009-01-15

Cross-sectional imaging with CT, MRI and more recently PET CT plays an indispensable complementary role to endoscopy in the pretherapeutic diagnostic and staging of laryngeal neoplasms and in the evaluation of the operated or irradiated larynx. Adequate interpretation of the CT, PET CT and MR images requires a thorough knowledge of the patterns of submucosal spread and familiarity with the diagnostic signs of neoplastic invasion as seen with each modality. In addition, one should be aware of the implications of imaging for staging and treatment. Both CT and MR imaging are highly sensitive for the detection of neoplastic invasion of the preepiglottic and paraglottic spaces, subglottic region and cartilage. The high negative predictive value of both CT and MRI allows a relatively reliable exclusion of neoplasm cartilage invasion. The specificity of both CT and MRI is, however, moderately high and both methods may, therefore, overestimate the extent of tumor spread. However, recent investigations have shown that the specificity of MRI may be significantly improved by using new diagnostic criteria which allow differentiation of tumor from peritumoral inflammation in many instances. Both cross-sectional imaging methods also significantly improve the pretherapeutic staging accuracy of laryngeal tumors if used in addition to clinical examination and endoscopic biopsy. In the presence of a submucosal mass, CT and MRI play a key role for the diagnosis, as they may characterize the lesion, reliably depict its submucosal extent and guide the endoscopist to perform deep biopsies which allow the definitive histological diagnosis. Cross-sectional imaging also plays a key role in the evaluation of laryngoceles, recurrent laryngeal nerve paralysis and fractures. (orig.) [German] Sowohl CT als auch MRT und neuerdings die PET-CT sind unentbehrliche Zusatzuntersuchungen zur Diagnostik und Stadieneinteilung von Tumoren des Larynx. Sie sind der klinischen Untersuchung (einschliesslich

MR imaging and CT findings after liver transplantation

International Nuclear Information System (INIS)

Langer, M.; Langer, R.; Scholz, A.; Zwicker, C.; Astinet, F.

1990-01-01

The aim of the paper is to evaluate MR imaging and dynamic CT as noninvasive procedures to image signs of graft failure after an orthotopic liver transplantation (OLT). Thirty MR studies and 50 dynamic CT examinations were performed within 20 days after OLT. MR examinations were performed with a 0.5-T Siemens Magnetom. CT scans were obtained by using a Siemens Somatom Plus. In all patients, MR images demonstrated a perivascular rim of intermediate signal intensity on T1-weighted and increased signal intensity on T2-weighted images in the hilum of the liver; in 20/26, this was seen in peripheral areas also. In all patients, a perivascular area of low attenuation was diagnosed at angio-CT

Struma ovarii. MR and CT appearance

International Nuclear Information System (INIS)

Joja, Ikuo; Mitsumori, Akihito; Hiraki, Yoshio; Kudo, Takafumi; Nakagawa, Tomio; Asakawa, Toru; Ando, Masaaki; Akamatsu, Nobuo.

1997-01-01

The purpose of this study was to examine the appearance of struma ovarii on MR and CT images. All 13 patients showed both cystic and solid components with a multilobulated surface and thickened septa. Various signal intensities were seen on both T1WI and T2WI. The cystic component, which showed low signal intensity on T2WI, showed high density on CT images. The characteristic MR and CT appearance of struma ovarii appears to be that of multicystic tumor indicating the presence of viscid materials containing iodine. (author)

Measurement of skeletal muscle area: Comparison of CT and MR imaging

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Sinelnikov, Andrey, E-mail: sinelnikovas@upmc.edu [Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Qu, Chuanxing [Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Fetzer, David T. [Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX (United States); Pelletier, Jean-Sébastien [Department of Surgery, Jewish General Hospital, McGill University, Montreal, Quebec (Canada); Dunn, Michael A. [Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Tsung, Allan [Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Furlan, Alessandro [Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA (United States)

2016-10-15

Objective: To investigate the intra- and inter-observer agreement and correlation between CT and MR measurements of skeletal muscle area (SMA) in the abdomen. Methods: CT and MR images from twelve patients were analyzed by two blinded observers using segmentation software (MITK-3M3, Mint Medical and Slice-O-Matic, Tomovision) to quantify SMA. MR images included T1w “in-phase”, T1w “out-of-phase”, and T2w sequences. Inter- and intra-observer agreement was assessed using the intraclass correlation coefficient (ICC). Pearson correlation coefficient (r) was used to correlate measurements obtained on MR with CT. CT and MR measurements were compared with Bland-Altman plots. Results: Intra- and inter-observer agreement for SMA was high for CT and MR. For MR, the measurements on T2w images showed the highest inter-observer agreement (ICC = 0.96). CT SMA correlated closely with MR, with T2w images showing the highest correlation (r = 0.98; P < 0.01). Bland-Altman plots showed a 1.7%–3.9% bias between CT and MR measurements, lowest for T2w images. Conclusions: MR SMA measurements are reproducible and correlate closely with CT. The T2w sequence is recommended to quantify SMA on MR images.

CT and MR angiography

International Nuclear Information System (INIS)

Bert, A.L.; Marshal, G.

1995-01-01

CT-angiography is a new vessel imaging technique based on the volumetric scanning of the region of interst during the first pass of IV bolus injection of contrast medium. MR-angiography is a titally noninvasive technique. The differentiation of flowing blood from the adjecent stationary tissues is based on the detection of blood motion. The flowing blood is highlighted with white light. CT- and MR-angiographic techniques are used to establish% stenoses and occlusions in intracranial arteries; aneurisms; trombosis of intracranial veins and venous angioma; diseases of neck vessels, thoracic vessels, abdominal vessels. Blood flow direction in cirrotic patients with portal hypertension can be determined in the portal vein, as well as the presence of thrombosis

Use of the CT component of PET-CT to improve PET-MR registration: demonstration in soft-tissue sarcoma

International Nuclear Information System (INIS)

Somer, Edward J; Benatar, Nigel A; O'Doherty, Michael J; Smith, Mike A; Marsden, Paul K

2007-01-01

We have investigated improvements to PET-MR image registration offered by PET-CT scanning. Ten subjects with suspected soft-tissue sarcomas were scanned with an in-line PET-CT and a clinical MR scanner. PET to CT, CT to MR and PET to MR image registrations were performed using a rigid-body external marker technique and rigid and non-rigid voxel-similarity algorithms. PET-MR registration was also performed using transformations derived from the registration of CT to MR. The external marker technique gave fiducial registration errors of 2.1 mm, 5.1 mm and 5.3 mm for PET-CT, PET-MR and CT-MR registration. Target registration errors were 3.9 mm, 9.0 mm and 9.3 mm, respectively. Voxel-based algorithms were evaluated by measuring the distance between corresponding fiducials after registration. Registration errors of 6.4 mm, 14.5 mm and 9.5 mm, respectively, for PET-CT, PET-MR and CT-MR were observed for rigid-body registration while non-rigid registration gave errors of 6.8 mm, 16.3 mm and 7.6 mm for the same modality combinations. The application of rigid and non-rigid CT to MR transformations to accompanying PET data gives significantly reduced PET-MR errors of 10.0 mm and 8.5 mm, respectively. Visual comparison by two independent observers confirmed the improvement over direct PET-MR registration. We conclude that PET-MR registration can be more accurately and reliably achieved using the hybrid technique described than through direct rigid-body registration of PET to MR

A case of hemorrhagic pineal cyst: MR/CT correlation

International Nuclear Information System (INIS)

Osborn, R.E.

1989-01-01

A 30-year-old male had headache pain for one month and was evaluated with both computed tomography (CT) and magnetic resonance (MR). These scans demonstrated an obstructing pineal cyst containing layered acute and subacute blood products by MR criteria. The concurrent scans allowed correlation between CT and MR findings in this rare complication of an unusual entity, explained his headache (and the development of later upward gaze paresis), provided a precise surgical/anatomic approach, and gave a good final clinical result. The report illustrates appropriate CT and MR images and pathological specimen. (orig.)

Rhabdomyosarcoma of children in the head and neck : CT and MR finding

International Nuclear Information System (INIS)

Park, Byung Kwan; Kim, In One; Kim, Woo Sun; Han, Sang Wook; Kim, Hyun Beom; Yeon, Myung Mo

1998-01-01

The purpose of this study is to evaluate radiologic findings of rhabdomyosarcoma of children in the head and neck concerning the origin, morphologic characteristics, extent, and the route of intracranial extension on CT and MR. Twenty cases of pathologically proven rhabdomyosarcoma were analyzed. Fifteen CT scans (postcontrast CT (n=13), precontrast CT (n=2)) and eleven MR scans were obtained. Postcontrast MR scans were performed in the ten cases. Six cases had CT and MR scans. Nine cases had only CT scan and five had only MR scans. We retrospectively analyzed the origin, morphologic characteristics (attenuation, signal intensity, margin), extent,intracranial extension, route and clinical staging of rhabdomyosarcoma on CT and MR scans. Rhabdomyosarcoma of children in the head and neck tends to show relatively severe bony destruction of skull base and various intracranial extension routes can be helpful radiologic findings on the CT or MR scan although its CT density or signal intensity of MR was not specific. And it is peculiar that infratempral fossa was the most common site of origin of rhabdomyosarcoma. (author). 28 refs., 2 tabs., 5 figs

Mr. Robot: Schizophrenie, Paranoia und korporative Gier

Directory of Open Access Journals (Sweden)

jan jagodzinski

2016-11-01

Full Text Available Der vorliegende Beitrag untersucht die erste Staffel von Mr. Robot (2015 − aus Gilles Deleuzes symptomatologischer Position, die sich auf das Spannungsfeld zwischen ‹dem Klinischen und dem Kritischen› fokussiert. Zum Zeitpunkt des Verfassens dieses Artikels war nur die erste Staffel verfügbar. Im Folgenden zeige ich am Beispiel der Hauptfigur Elliot Anderson, inwiefern die Serie Einblicke in unsere ‹Kontrollgesellschaft› – auch eine Deleuzsche Entwicklung – gewähren kann. Zudem wird ein Vergleich mit dem Film «Kein System ist sicher», der ähnliche gesellschaftliche Fragen thematisiert, vorgenommen. Obwohl ich auf medienpädagogische Aspekte nur indirekt eingehen werde, hebe ich im Laufe der Argumentation hervor, dass solche Fernsehnarrative das allgemeine Publikum oder das, was ich als ‹jedermann› beschreibe, mit ethischen Problemen und Dilemmata unserer globalen kapitalistischen Ordnung konfrontieren.

Craniopharyngioma identification by CT and MR imaging at 1.5 T

Energy Technology Data Exchange (ETDEWEB)

Hald, J.K. [Dept. of Radiology, Rikshospitalet, Oslo Univ. (Norway)]|[Dept. of Radiology, Univ. of Michigan Hospitals, Ann Arbor, MI (United States); Eldevik, O.P. [Dept. of Radiology, Rikshospitalet, Oslo Univ. (Norway)]|[Dept. of Radiology, Univ. of Michigan Hospitals, Ann Arbor, MI (United States); Skalpe, I.O. [Dept. of Radiology, Rikshospitalet, Oslo Univ. (Norway)]|[Dept. of Radiology, Univ. of Michigan Hospitals, Ann Arbor, MI (United States)

1995-03-01

To compare the detectability of craniopharyngiomas by CT and MR imaging, preoperative CT and MR studies obtained within 16 days of each other were evaluated retrospectively in 9 patients. MR imaging demonstrated cystic and solid tumor components in all 9 tumors, and enhancement in the 7 tumors that were studied after contrast medium injection. MR imaging demonstrated a signal void consistent with calcification in 4 patients. Combining unenhanced and contrast medium-enhanced studies, CT also identified all the tumors. CT demonstrated cysts in 7 lesions, calcification in 7 and enhancement in 6 of the 7 lesions that received i.v. contrast medium. Calcification was better seen by CT than MR imaging, while MR imaging identified cystic tumor components not seen on CT. The contrast medium enhancement pattern was the same with the 2 modalities. MR imaging of the sellar region, including at least one contrast medium-enhanced sequence, should be sufficient in most instances to establish a preoperative diagnosis of craniopharyngioma. (orig.).

MR-Venography Using High Resolution True-FISP

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Spuentrup, E. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Beth Israel Deaconess Medical Center, Boston, MA (United States). Dept. of Medicine; Harvard Medical School, Boston, MA (United States); Buecker, A.; Guenther, R.W. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Stuber, M. [Beth Israel Deaconess Medical Center, Boston, MA (United States). Dept. of Medicine; Harvard Medical School, Boston, MA (United States); Philips Med. Syst., Best (Netherlands)

2001-08-01

A new fast MR-venography approach using a high resolution True-FISP imaging sequence was investigated in 20 patients suffering from 23 deep vein thromboses. Diagnosis was proven by X-ray venography, CT or ultrasound examination. The presented technique allowed for clear thrombus visualization with a high contrast to the surrounding blood pool even in calf veins. Acquisition time was less than 10 minutes for imaging the pelvis and the legs. No contrast media was needed. The presented high resolution True-FISP MR-veography is a promising non-invasive, fast MR-venography approach for detection of deep venous thrombosis. (orig.) [German] Eine neue schnelle, oertlich hochaufgeloeste MR-Phlebographietechnik mit einer axialen True-FISP Bildgebungssequenz wurde an 20 Patienten mit 23 nach-gewiesenen tiefen Beinvenenthrombosen untersucht. Die Befunde wurden mit einer konventionellen Roentgenphlebographie, einer CT oder einer Sonographie gesichert. Die vorgestellte Technik erlaubte in allen Faellen eine Thrombusdarstellung mit hohem Kontrast zum umgebenden venoesen Blut, wobei aufgrund der hohen Ortsaufloesung auch die Unterschenkelvenen beurteilt werden konnten. Die Datenaufnahmezeit zur Untersuchung des Beckens und der Beine betrug weniger als 10 Minuten. Kontrastmittel wurde nicht benoetigt. Die vorgestellte MR-Phlebographietechnik unter Verwendung einer oertlich hochauf-geloesten True-FISP Sequenz ist eine neue, vielversprechende, nicht-invasive Technik zur Diagnostik der tiefen Bein- und Beckenvenenthrombose. (orig.)

CT-diskography in patients with sciatica. Comparison with plain CT and MR imaging

Energy Technology Data Exchange (ETDEWEB)

Dullerud, R. [Ullevaal Univ. Hospital, Oslo (Norway). Section of Neuroradiology; Johansen, J.G. [Ullevaal Univ. Hospital, Oslo (Norway). Section of Neuroradiology

1995-09-01

The findings at CT-diskography (CT-D), including recording of the pain introduced at contrast injection, were compared with plain CT and MR imaging in 111 disks in 101 patients aged 18 to 68 years. Six disks which were normal at CT had normal CT-D and 5 of them had normal signal on MR imaging. The degree of annular degeneration and the depth of the annular tears were significantly associated with each other and with loss of disk height, but not with size or location of the hernias. Only the depth of the tears was significantly associated with loss of signal on MR. However, frequently complete annular tears and severe annular degeneration were seen in association with small bulges and hernias, even in disks with normal or slightly reduced signal on MR and with normal height. The type and intensity of the pain introduced were associated with each other and with the depth of the annular tears, but not with the degree of annular degeneration, size of the hernia or the MR signal intensity of the disks. Annular degeneration and tears on one hand, and the type and intensity of pain introduced on the other, see to be related rather than separate phenomena. (orig./MG).

CT-diskography in patients with sciatica. Comparison with plain CT and MR imaging

International Nuclear Information System (INIS)

Dullerud, R.; Johansen, J.G.

1995-01-01

The findings at CT-diskography (CT-D), including recording of the pain introduced at contrast injection, were compared with plain CT and MR imaging in 111 disks in 101 patients aged 18 to 68 years. Six disks which were normal at CT had normal CT-D and 5 of them had normal signal on MR imaging. The degree of annular degeneration and the depth of the annular tears were significantly associated with each other and with loss of disk height, but not with size or location of the hernias. Only the depth of the tears was significantly associated with loss of signal on MR. However, frequently complete annular tears and severe annular degeneration were seen in association with small bulges and hernias, even in disks with normal or slightly reduced signal on MR and with normal height. The type and intensity of the pain introduced were associated with each other and with the depth of the annular tears, but not with the degree of annular degeneration, size of the hernia or the MR signal intensity of the disks. Annular degeneration and tears on one hand, and the type and intensity of pain introduced on the other, see to be related rather than separate phenomena. (orig./MG)

An Investigation of Methods for CT Synthesis in MR-only Radiotherapy

DEFF Research Database (Denmark)

Andreasen, Daniel

In recent years, the interest in using magnetic resonance (MR) imaging in radiotherapy (RT) has increased. This is because MR has a superior soft tissue contrast compared to computed tomography (CT), which makes it a better modality for delineating the target volume (tumor) and possible organs...... at risk (OARs). In an MR/CT work-flow, independent MR and CT scans are acquired. The target and possible OARs are delineated on the MR and then transferred to CT by aligning the data using a registration. This introduces the risk of systematic registration errors especially in non-rigid body structures......, the consequence being a systematic miss of target or increased dose to healthy tissue. Radiotherapy based on MR as the only modality removes this uncertainty and simplifies the clinical work-flow. However, the information on electron density which is usually contained in the CT must now be derived from the MR...

Functional-anatomic evaluation of dilated uropathies in children using combined MR-nephrography and MR-urography compared to renal scintigraphy; Funktionell-anatomische Diagnostik dilatierter Uropathien bei Kindern mit kombinierter MR-Nephrographie und MR-Urographie im Vergleich zur renalen Isotopennephrographie

Energy Technology Data Exchange (ETDEWEB)

Reither, M. [Abt. fuer bildgebende Diagnostik am Kinderkrankenhaus Park Schoenfeld, Kassel (Germany); Tuerkay, S. [GE Medical Systems Deutschland GmbH, Solingen (Germany)

2004-02-01

Purpose: to evaluate MR-tomographic assessment of split renal function and degree of obstruction compared to diuretic renal scintigraphy, and pathoanatomic imaging of the urinary tract as all in one exam. Patients and methods: in a prospective study 62 children, aged 1 month to 9.5 years, mean 2.8 years, underwent diuretic renal scintigraphy and dynamic MR-nephrography at the same day except for 7 patients with a time interval of 1 day. In all patients we did T2w (water-technique) MR-urography additionally. Results: comparing spilt renal function we found a very close correlation in 54 out of 62 patients (correlation coefficient = 0.95). Due to technical failures 8 cases couldn't be calculated. Comparing degrees of obstruction there was an agreement in 57 out of 62 patients, 3 studies were gradually over-, 2 underestimated. All but one morphologic diagnoses in advance obtained by ultrasound and completed by other imaging modalities later on were confirmed MR-urographically. Though correctly imaged the functionless upper moiety in a renal duplication with ureterocele was misinterpreted at a first glance. (orig.) [German] Ziel: Es sollte geprueft werden, ob die Berechnung der seitengetrennten Nierenfunktion, die Bestimmung des Obstruktionsgrades und die pathoanatomische Darstellung des Harntraktes im Vergleich zur Diurese-Szintigraphie in einem Untersuchungsgang MR-tomographisch zuverlaessig moeglich ist. Patienten und Methode: In einer prospektiven Studie wurden bei 62 Kindern im Alter von 1 Monat bis 9,5 Jahren, Mittelwert 2,8 Jahre, ein Diurese-Szintigramm und eine dynamische MR-Nephrographie am gleichen Tag durchgefuehrt; lediglich bei 7 Patienten lag 1 Tag zwischen beiden Untersuchungen. Alle Patienten erhielten zusaetzlich eine T2w-MR-Urographie in ''Wasserbild''-Technik. Ergebnisse: Beim Vergleich der seitengetrennten Nierenfunktion fand sich eine sehr enge Korrelation bei 54 von insgesamt 62 Patienten (Korrelationskoeffizient = 0

MR imaging and CT in osteoarthritis of the lumbar facet joints

International Nuclear Information System (INIS)

Weishaupt, D.; Zanetti, M.; Hodler, J.; Boos, N.

1999-01-01

Objective. To test the agreement between MR imaging and CT in the assessment of osteoarthritis of the lumbar facet joints, and thus to provide data about the need for an additional CT scan in the presence of an MR examination. Design and patients. Using a four-point scale, two musculoskeletal radiologists independently graded the severity of osteoarthritis of 308 lumbar facet joints on axial T2-weighted and on sagittal T1- and T2-weighted turbo-spin-echo images and separately on the corresponding axial CT scans. Kappa statistics and percentage agreement were calculated. Results. The weighted kappa coefficients for MR imaging versus CT were 0.61 and 0.49 for readers 1 and 2, respectively. The weighted kappa coefficients for interobserver agreement were 0.41 for MR imaging and 0.60 for CT, respectively. There was agreement within one grade between MR and CT images in 95% of cases for reader 1, and in 97% of cases for reader 2. Conclusion. With regard to osteoarthritis of the lumbar facet joints there is moderate to good agreement between MR imaging and CT. When differences of one grade are disregarded agreement is even excellent. Therefore, in the presence of an MR examination CT is not required for the assessment of facet joint degeneration. (orig.)

Left and right ventricle assessment with Cardiac CT: validation study vs. Cardiac MR

Energy Technology Data Exchange (ETDEWEB)

Maffei, Erica; Seitun, Sara [Giovanni XXIII Hospital, Cardiovascular Radiology Unit, Monastier di Treviso (Italy); Messalli, Giancarlo; Catalano, Onofrio [SDN Foundation - IRCCS, Naples (Italy); Martini, Chiara; Cademartiri, Filippo [Giovanni XXIII Hospital, Cardiovascular Radiology Unit, Monastier di Treviso (Italy); Erasmus Medical Center, Department of Radiology and Cardiology, Rotterdam (Netherlands); Nieman, Koen; Rossi, Alexia; Mollet, Nico R. [Erasmus Medical Center, Department of Radiology and Cardiology, Rotterdam (Netherlands); Guaricci, Andrea I. [Azienda Ospedaliero-Universitaria di Foggia, Department of Cardiology, Foggia (Italy); Tedeschi, Carlo [Ospedale San Gennaro, Department of Cardiology, Naples (Italy)

2012-05-15

To compare Magnetic Resonance (MR) and Computed Tomography (CT) for the assessment of left (LV) and right (RV) ventricular functional parameters. Seventy nine patients underwent both Cardiac CT and Cardiac MR. Images were acquired using short axis (SAX) reconstructions for CT and 2D cine b-SSFP (balanced-steady state free precession) SAX sequence for MR, and evaluated using dedicated software. CT and MR images showed good agreement: LV EF (Ejection Fraction) (52 {+-} 14% for CT vs. 52 {+-} 14% for MR; r = 0.73; p > 0.05); RV EF (47 {+-} 12% for CT vs. 47 {+-} 12% for MR; r = 0.74; p > 0.05); LV EDV (End Diastolic Volume) (74 {+-} 21 ml/m{sup 2} for CT vs. 76 {+-} 25 ml/m{sup 2} for MR; r = 0.59; p > 0.05); RV EDV (84 {+-} 25 ml/m{sup 2} for CT vs. 80 {+-} 23 ml/m{sup 2} for MR; r = 0.58; p > 0.05); LV ESV (End Systolic Volume)(37 {+-} 19 ml/m{sup 2} for CT vs. 38 {+-} 23 ml/m{sup 2} for MR; r = 0.76; p > 0.05); RV ESV (46 {+-} 21 ml/m{sup 2} for CT vs. 43 {+-} 18 ml/m{sup 2} for MR; r = 0.70; p > 0.05). Intra- and inter-observer variability were good, and the performance of CT was maintained for different EF subgroups. Cardiac CT provides accurate and reproducible LV and RV volume parameters compared with MR, and can be considered as a reliable alternative for patients who are not suitable to undergo MR. circle Cardiac-CT is able to provide Left and Right Ventricular function. circle Cardiac-CT is accurate as MR for LV and RV volume assessment. (orig.)

CT and MR imaging characteristics of infantile hepatic hemangioendothelioma

International Nuclear Information System (INIS)

Feng Shiting; Chan Tao; Ching, A.S.C.; Sun Canhui; Guo Huanyi; Fan Miao; Meng Quanfei; Li Ziping

2010-01-01

Aim: This study aims to analyze computed tomography (CT) and magnetic resonance (MR) imaging features of infantile hepatic hemangioendotheliomas before and after treatment. Materials and methods: CT and MR examinations of seven infants with biopsy proven hepatic hemangioendotheliomas were retrospectively analyzed. The distribution, number, size, imaging appearance, enhancement pattern and post-treatment changes of the tumors were evaluated. Results: A total of 153 hepatic hemangioendotheliomas were detected on CT (111) and MR (42) imaging. In six infants, 109/111 (98.2%) tumors were hypodense and 2/111 (1.8%) lesions contained calcification on unenhanced CT. On MR imaging, all 42 lesions in one infant were heterogeneously T1-hypointense and T2-hyperintense compared to the normal liver parenchyma. Contrast-enhanced CT and MRI showed peripheral rim (51.6%), uniform (48.4%), fibrillary (33.3%), and nodular (28.8%) contrast enhancement in the hepatic arterial phase. Homogeneous (100%), rim (98.2%) and mixed enhancement patterns were noted in tumors 2.0 cm and 1.0-2.0 cm in diameter respectively in the hepatic arterial phase. In three patients who underwent steroid therapy, follow-up CT examination demonstrated tumor size reduction and increased intra-tumoral calcification in two patients. Conclusion: Infantile hepatic hemangioendotheliomas show some typical imaging features and size-dependent pattern of contrast enhancement on CT and MR imaging, which allow accurate imaging diagnosis and post-treatment evaluation.

Temporal lobe epilepsy: Comparison of CT and MR in 100 patients

International Nuclear Information System (INIS)

Schoerner, W.; Meencke, H.J.; Sander, B.; Henkes, H.; Felix, R.; Klinikum Rudolf Virchow, Berlin

1989-01-01

The value of CT and MR was studied in 100 patients with temporal lobe epilepsy. Axial CT scans were obtained before and after contrast injection. Coronary MR scans were carried out with T 1 -(SE 400/30, GE 315/14) and T 2 -weighted sequences (SE 1600/30 + 70). A circumscribed lesion was demonstrated in fifteen patients by CT and in 25 patients by MR. With the exception of a small area of calcification, all lesions seen on CT could also be recognized on MR. Better sensitivity and improved demonstration of the temporal lobes makes MR the method of choice in the diagnosis of temporal lobe epilepsy. (orig./GDG) [de

Hypothalamic-pituitary dwarfism: Comparison between MR imaging and CT findings

International Nuclear Information System (INIS)

Maghnie, M.; Larizza, D.; Severi, F.; Triulzi, F.; Scotti, G.; Beluffi, G.; Cecchini, A.

1990-01-01

Magnetic Resonance (MR) imaging was carried out on 33 patients with idiopathic growth hormone deficiency, in 22 of whom CT scan had been carried out previously. Twenty-one patients presented some complications at birth. Both MR and CT were positive in the evaluation of the sella. MR imaging exhibited a higher degree of accuracy than CT in the evaluation of pituitary gland, pituitary stalk and brain anomalies. (orig.)

Investigating the generalisation of an atlas-based synthetic-CT algorithm to another centre and MR scanner for prostate MR-only radiotherapy

Science.gov (United States)

Wyatt, Jonathan J.; Dowling, Jason A.; Kelly, Charles G.; McKenna, Jill; Johnstone, Emily; Speight, Richard; Henry, Ann; Greer, Peter B.; McCallum, Hazel M.

2017-12-01

There is increasing interest in MR-only radiotherapy planning since it provides superb soft-tissue contrast without the registration uncertainties inherent in a CT-MR registration. However, MR images cannot readily provide the electron density information necessary for radiotherapy dose calculation. An algorithm which generates synthetic CTs for dose calculations from MR images of the prostate using an atlas of 3 T MR images has been previously reported by two of the authors. This paper aimed to evaluate this algorithm using MR data acquired at a different field strength and a different centre to the algorithm atlas. Twenty-one prostate patients received planning 1.5 T MR and CT scans with routine immobilisation devices on a flat-top couch set-up using external lasers. The MR receive coils were supported by a coil bridge. Synthetic CTs were generated from the planning MR images with (sCT1V ) and without (sCT) a one voxel body contour expansion included in the algorithm. This was to test whether this expansion was required for 1.5 T images. Both synthetic CTs were rigidly registered to the planning CT (pCT). A 6 MV volumetric modulated arc therapy plan was created on the pCT and recalculated on the sCT and sCT1V . The synthetic CTs’ dose distributions were compared to the dose distribution calculated on the pCT. The percentage dose difference at isocentre without the body contour expansion (sCT-pCT) was Δ D_sCT=(0.9 +/- 0.8) % and with (sCT1V -pCT) was Δ D_sCT1V=(-0.7 +/- 0.7) % (mean  ±  one standard deviation). The sCT1V result was within one standard deviation of zero and agreed with the result reported previously using 3 T MR data. The sCT dose difference only agreed within two standard deviations. The mean  ±  one standard deviation gamma pass rate was Γ_sCT = 96.1 +/- 2.9 % for the sCT and Γ_sCT1V = 98.8 +/- 0.5 % for the sCT1V (with 2% global dose difference and 2~mm distance to agreement gamma criteria). The one voxel body contour

MR-guided focused ultrasound. Current and future applications; MR-gesteuerter fokussierter Ultraschall. Aktuelle und potenzielle Indikationen

Energy Technology Data Exchange (ETDEWEB)

Trumm, C.G.; Peller, M.; Clevert, D.A.; Stahl, R.; Reiser, M. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen-Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany); Napoli, A. [Sapienza Universitaet Rom, Abteilung fuer Radiologie (Department of Radiological Sciences), MRgFUS and Cardiovascular Imaging Unit, Rom (Italy); Matzko, M. [Klinikum Dachau, Abteilung fuer diagnostische und interventionelle Radiologie, Dachau (Germany)

2013-03-15

High-intensity focused ultrasound (synonyms FUS and HIFU) under magnetic resonance imaging (MRI) guidance (synonyms MRgFUS and MR-HIFU) is a completely non-invasive technology for accurate thermal ablation of a target tissue while neighboring tissues and organs are preserved. The combination of FUS with MRI for planning, (near) real-time monitoring and outcome assessment of treatment markedly enhances the safety of the procedure. The MRgFUS procedure is clinically established in particular for the treatment of symptomatic uterine fibroids, followed by palliative ablation of painful bone metastases. Furthermore, promising results have been shown for the treatment of adenomyosis, malignant tumors of the prostate, breast and liver and for various intracranial applications, such as thermal ablation of brain tumors, functional neurosurgery and transient disruption of the blood-brain barrier. (orig.) [German] MRT-gesteuerter hochintensiver fokussierter Ultraschall (MRgFUS bzw. MR-HIFU) ist ein nichtinvasives Verfahren zur praezisen Thermoablation eines Zielgewebes. Bei dieser Methode werden benachbarte Gewebe und Organe geschont. Die Kombination des fokussierten Ultraschalls (FUS) mit der MRT zwecks Planung und Monitoring (nahezu) in Echtzeit sowie zur Erfolgskontrolle von Behandlungen traegt wesentlich zur Sicherheit dieser Methode bei. MRgFUS ist klinisch v. a. zur Behandlung von symptomatischen Uterusmyomen etabliert, gefolgt von der palliativen Ablation von Knochenmetastasen. Weitere vielversprechende Anwendungsgebiete des MRgFUS sind die Adenomyose des Uterus, die Behandlung von Prostata-, Mamma- und Lebertumoren sowie der intrakranielle Einsatz. (orig.)

MR-guided biopsies of undetermined liver lesions: technique and results; MRT-gezielte perkutane Biopsie bei unklaren fokalen Leberlaesionen: Technik und Ergebnisse

Energy Technology Data Exchange (ETDEWEB)

Zangos, S.; Kiefl, D.; Eichler, K.; Engelmann, K.; Heller, M.; Herzog, C.; Mack, M.G.; Jacobi, V.; Vogl, T.J. [Inst. fuer Diagnostische und Interventionelle Radiologie, Johann-Wolfgang-Goethe-Univ. Frankfurt (Germany)

2003-05-01

Purpose: To evaluate safety and precision of liver tumor biopsies performed in an open low field system using different sequence techniques. Materials and Methods: In 47 patients with liver tumors, MR-guided biopsies were performed in a low field system (0.2 Tesla, Magnetom Open, Siemens) using two different sequences. The procedure was monitored with T1-weighted FLASH sequences (TR/TE = 100/9; 70 ) in all patients and with FISP-Rotated-Keyhole-sequence (TR/TE = 18/8; 90 ) in additional 20 patients. After positioning of the needle tip in the tumors, 166 biopsy specimens were acquired with 16 G cutting needles (Somatex{sup *}). The diameter of the biopsied lesions ranged from 1 to 10 cm (mean diameter 3.2 cm). Visibility of the needles and precision of the biopsies were evaluated. Results: All interventional biopsies were performed without vascular or organ injuries. Adequate specimens for histologic interpretation were obtained in 42 cases (89.3%). The biopsy results were non-specific in 2 patients (4.2%) and the lesions missed in 3 patients (6.3%). Mean in-room time was 35 minutes and the intervention time was 8.3 minutes. T1-weighted FLASH images proved optimal for confirming needle-tip placement during the biopsies or punctures. Organs, tumors and vessels were easily identified. The FISP sequence proved to be inferior in visualizing vessels and tumors. Conclusion: MR-guided liver biopsies are safely and precisely performed using T1-weighted FLASH-sequences with sufficient visualization of the lesions and might be complementary to US- or CT-guided biopsies. (orig.) [German] Zielsetzung: Evaluierung der Sicherheit und Genauigkeit MRT-gezielter Leberbiopsien unter Verwendung verschiedener Sequenzen. Methoden: Bei 47 Patienten mit unklaren Leberlaesionen wurden in einem offenen 0,2-Tesla-MR-System (Magnetom Open, Siemens) bildgesteuerte Biopsien unter Verwendung von zwei verschiedenen Sequenzen durchgefuehrt. Die Bildgebung erfolgte bei allen Patienten mittels T

Flair MR imaging in the Detection of subarachnoid hemorrhage : comparison with CT and T1-weighted MR imaging

Energy Technology Data Exchange (ETDEWEB)

Min, Soo Hyun; Kim, Soo Youn; Lee, Ghi Jai; Shim, Jae Chan; Oh, Tae Kyung; Kim, Ho Kyun [College of Medicine, Jnje University, Seoul (Korea, Republic of)

2000-03-01

To compare the findings of fluid-attenuated inversion recovery (FLAIR) MR imaging in the detection of subarachnoid hemorrhage (SAH), with those of precontrast CT and T1-weighted MR imaging. In 13 patients (14 cases) with SAH, FLAIR MR images were retrospectively analyzed and compared with CT (10 patients, 11 cases) and T1-weighted MR images (9 cases). SAH was confirmed on the basis of high density along the subarachnoid space, as seen on precontrast CT, or lumbar puncture. MR imaging was performed on a 1.0T unit. FLAIR MR and CT images were obtained during the acute stage(less than 3 days after ictus) in 10 and 9 cases, respectively, during the subacute stage (4-14 days after ictus) in two cases and one, respectively, and during the chronic stage (more than 15 days after ictus) in two cases and one, respectively. CT was performed before FLAIR MR imaging, and the interval between CT and FLAIR ranged from 24 hours (6 cases) to 2-3 (2 cases) or 4-7 days (3 cases). In each study, the conspicuity of visualization of SAH was graded as excellent, good, fair, or negative at five locations (sylvian fissure, cortical sulci, anterior basal cistern, posterior basal cistern, and perimesencephalic cistern). In all cases, subarachnoid hemorrhages were demonstrated as high signal intensity areas on FLAIR images. The detection rates for SAH on CT and T1-weighted MR images were 100% (11/11) and 89% (8/9), respectively. FLAIR was superior to T1-weighted imaging in the detection of SAH at all sites except the anterior basal cistern (p less than 0.05) and superior to CT in the detection of SAH at the cortical sulci (p less than 0.05). On FLAIR MR images, subarachnoid hemorrhages at all stages are demonstrated as high signal intensity areas; the FLAIR MR sequence is thus considered useful in the detection of SAH. In particular FLAIR is more sensitive than CT for the detection of SAH in the cortical sulci. (author)

CT and MRI of the liver: when, what, why?; CT und MRT der Leber: wann, was, warum

Energy Technology Data Exchange (ETDEWEB)

Budjan, J.; Schoenberg, S.O.; Attenberger, U.I. [Medizinische Fakultaet Mannheim der Universitaet Heidelberg, Institut fuer Klinische Radiologie und Nuklearmedizin, Universitaetsmedizin Mannheim, Mannheim (Germany)

2017-05-15

The detection and differential diagnostic clarification of liver pathologies play an important role in almost all medical disciplines. Because of its superior soft tissue contrast, the availability of liver-specific contrast agents and functional techniques, magnetic resonance imaging (MRI) is the method of choice for the diagnostics of focal and diffuse liver pathologies. In addition to its superior detection and differentiation capabilities, MRI can provide prognostic information and enable early assessment of the therapy response for malignant liver lesions using functional techniques, especially diffusion imaging. Computed tomography (CT) is the imaging method of choice for the detection of traumatic liver injury. Despite the increasing availability of functional techniques in CT, MRI remains the overall modality of choice in liver imaging. (orig.) [German] Die Detektion und die differenzialdiagnostische Abklaerung von Leberpathologien spielen in nahezu allen medizinischen Disziplinen eine bedeutende Rolle. Ihre Vorteile in Hinblick auf Weichteilkontrast, die Verfuegbarkeit leberspezifischer Kontrastmittel und funktionelle Techniken machen die MRT zum bildgebenden Verfahren der Wahl fuer die gezielte Abklaerung fokaler oder diffuser Leberpathologien. Neben hoeheren Detektionsraten und besseren Differenzierungsmoeglichkeiten stehen in der MRT funktionelle Techniken - insbesondere die Diffusionsbildgebung - zur Verfuegung, die eine Prognoseabschaetzung und die fruehe Beurteilung von Therapieansprechen bei malignen Leberlaesionen erlauben. Die CT ist bei der Detektion traumatischer Leberverletzungen Bildgebungsverfahren der Wahl; trotz der auch in der CT zunehmend verfuegbaren funktionellen Techniken bleibt die MRT in der Leberbildgebung weiterhin ueberlegen. (orig.)

Comparative evaluation of the porta hepatis/hepatoduodenal ligament with CT and MR imaging

International Nuclear Information System (INIS)

Silverman, P.M.; Feuerstein, I.M.; Zeman, R.K.; Jaffe, M.H.; Garra, B.S.

1988-01-01

CT and MR imaging were compared in a retrospective evaluation of 16 patients with abnormalities, predominantly neoplasms, of the porta hepatis/hepatoduodenal ligament. Masses on CT were of decreased density compared with that of liver and were seen in contrast to surrounding periportal fat. On MR images, T1-weighted images demonstrated findings similar to those of CT. T2-weighted images clearly depicted intrahepatic lesions but less distinctly depicted lesions surrounded by fat. Short inversion recovery (STIR) images better demonstrated tumor relative to fat. CT was better than all MR imaging sequences in one of 16 cases, whereas at least one MR imaging sequence was better than CT in six of 16. In nine cases, CT was equivalent to the best MR imaging sequence. In five of six cases where MR imaging was better than CT, STIR sequences were most favorable. In conclusion, MR imaging provided a valuable technique for assessing abnormalities of the porta hepatis/hepatoduodenal ligament

Effect of Attenuation Correction on Regional Quantification Between PET/MR and PET/CT

DEFF Research Database (Denmark)

Teuho, Jarmo; Johansson, Jarkko; Linden, Jani

2016-01-01

UNLABELLED: A spatial bias in brain PET/MR exists compared with PET/CT, because of MR-based attenuation correction. We performed an evaluation among 4 institutions, 3 PET/MR systems, and 4 PET/CT systems using an anthropomorphic brain phantom, hypothesizing that the spatial bias would be minimized....../MR systems, CTAC was applied as the reference method for attenuation correction. RESULTS: With CTAC, visual and quantitative differences between PET/MR and PET/CT systems were minimized. Intersystem variation between institutions was +3.42% to -3.29% in all VOIs for PET/CT and +2.15% to -4.50% in all VOIs...... for PET/MR. PET/MR systems differed by +2.34% to -2.21%, +2.04% to -2.08%, and -1.77% to -5.37% when compared with a PET/CT system at each institution, and these differences were not significant (P ≥ 0.05). CONCLUSION: Visual and quantitative differences between PET/MR and PET/CT systems can be minimized...

CT- and MR colonography

DEFF Research Database (Denmark)

Achiam, Michael Patrick; Bülow, Steffen; Rosenberg, J

2002-01-01

BACKGROUND: Colorectal cancer is the second most frequent cancer and adenomas are widely accepted as precursors to colorectal cancer. Diagnosis and removal of adenomas are recommended to reduce cancer incidence and mortality. The current diagnostic methods include sigmoidoscopy and colonoscopy....... CONCLUSIONS: With the exponential development in computer processing power, CT- and MR colonography holds the promise for future colon examination with the advantages of non-invasiveness, no need for sedation, and probably no bowel preparation. A major disadvantage, however, is the radiation dose during CT...

CT and MR findings in retinoblastoma : correlation with histopathologic examination

International Nuclear Information System (INIS)

Park, Son Won; Han, Moon Hee; Chi, Je G.; Yu, Young Suk; Kim, Yeon Mee; Chung, Jin Haeng; Yu, In Kyu; Chang, Kee Hyun; Yeon, Kyung Mo

1997-01-01

To evaluate histopathologic correlation of the component of the lesion on CT and MR of retinoblastomas. Gross pathologic findings of 24 enucleated eyeballs in 24 patients with retinoblastomas were compared with preoperative CT (n=19) and MR (n=5) findings. In eight eyeballs, in which there were findings other than mass, histopathologic findings were reviewed and correlated with image findings. Retinal detachment and subretinal hemorrhage which were not detected on CT were demonstrated in two of eight eyeballs on histopathologic examination. In one eyeball, retinal detachment and subretinal effusion were detected on both CT and in a pathologic specimen. In two eyeballs with peripheral heterogeneous MR enhancement of the masses, tumor necrosis and calcification were demonstrated in the central non-emhancing portion of the mass, In two eveballs, linear soft tissue along the retina apart from the main mass were revealed as tumor spread along the retinal surface. In one patient, retinal thickening on MR was presumed to be an MR artifact and no lesion was found in the gross specimen. On CT, retinal detachment and subretinal hemorrhage associated with retinoblastoma can mimic mass, and tumor spread along the retinal surface can be seen as a linear retinal lesion. On MR, tumor necrosis and calcification can be a cause of heterogeneous enhancement

CT and MR manifestations of acute methyl alcohol toxic encephalopathy

International Nuclear Information System (INIS)

Mao Xiaofen; Yang Bo; Ye Gengxin; Zhang Cheng

2009-01-01

Objective: To analyze the CT and MR manifestations of methyl alcohol toxic encephalopathy and to improve the diagnosing value of CT and MRI. Methods: 40 patients with methyl alcohol intoxication were collected in this study, in which CT scan was performed on 40 cases and MRI on 4 cases. All CT and MRI radiological data of brain were retrospectively studied. Results: 13 of 40 cases showed abnormal findings on brain CT and MRI. The most common manifestation (6/13, 46%)was hypodensity in frontal parietal white matter and external capsule-putamen on CT, which showed long or short T1 and long T2 on MR. Hemorrhage in right putamen was found only in 1 patient (1/13,7%). CT showed low density inbilateral external capsule in 4 cases (4/13,31%), in which MR showed long or short T1 and long T2. Low density lesions in subcortical white matter of bilateral frontal and parietal lobes, cingulate gyms and insular lobes were found in 2 patients (2/13,15%). The more severe clinic manifestation, the more obvious brain lesion CT and MRI showed. Conclusion: Brain CT and MR manifestations have great diagnostic value of acute methyl alcohol toxic encephalopathy. MRI was more sensitive and better than CT in finding early brain damage caused by methanol intoxication. (authors)

Comparison of MR imaging and CT in neuroendrocrine disorders in children

International Nuclear Information System (INIS)

Garreh, M.K.; Ball, W.S.; Brody, A.S.; Dolan, L.; Burton, E.M.

1989-01-01

MR imaging has been shown to be superior in imaging the adult hypothalamicpituitary axis. The authors have reviewed the CT and MR findings in children with known abnormalities, including hamartoma of the tuber cinereum, craniopharyngiomas,. pituitary adenoma, Rathke cleft cyst, incomplete pituitary stalk, and septo-optic dysplasia. Clinical correlation and typical CT and MR features were analyzed. In four cases, abnormalities were not visualized on CT. The authors conclude that because of its unique sensitivity and excellent anatomic resolution, MR imaging is the modality of choice in the imaging of neuroendocrine disorders in children

Usefulness of MR imaging for diseases of the small intestine: comparison with CT

Energy Technology Data Exchange (ETDEWEB)

Kim, Ji Hoon; Ha, Hyun Kwon; Sohn, Min Jae; Shin, Byung Suck; Lee, Young Suk; Chung, Soo Yoon; Kim, Pyo Nyun; Lee, Moon Gyu; Auh, Yong Ho [Ulsan University College of Medicine, Seoul (Korea, Republic of)

2000-03-01

To evaluate the usefulness of MR imaging for diseases of the small intestine, emphasizing a comparison with CT. Thirty-four patients who underwent both CT and MR imaging using FLASH 2D and HASTE sequences were analyzed. All patients had various small bowel diseases with variable association of peritoneal lesions. We compared the detectabilities of CT and MR imaging using different MR pulse sequences. The capability for analyzing the characteristics of small intestinal disease was also compared. MR imaging was nearly equal to CT for detecting intraluminal or peritoneal masses, lesions in the bowel and mesentery, and small bowel obstruction, but was definitely inferior for detecting omental lesions. The most successful MR imaging sequence was HASTE for demonstrating bowel wall thickening, coronal FLASH 2D for mesenteric lesions, and axial FLASH 2D for omental lesions. MR imaging yielded greater information than CT in six of 12 inflammatory bowel diseases, while it was equal to CT in six of seven neoplasms and inferior in five of seven mesenteric ischemia. In determining the primary causes of 15 intestinal obstructions, MR imaging was correct in 11 (73%) and CT in nine (60%) patients. MR imaging can serve as an alternative diagnostic tool for patients with suspected inflammatory bowel disease, small intestinal neoplasm or obstruction.

Comparative study of CT and MR guided cryoablation for hepatic tumors

International Nuclear Information System (INIS)

Wu Bin; Xiao Yueyong; Zhang Xiao; Li Hongjun; Li Jie; Yu Da

2010-01-01

Objective: To compare CT and MR imaging in guiding and monitor/ng cryoablation of hepatic tumors. Methods: A total of 131 lesions in 121 patients with malignant tumors of liver were treated with imaging-guided percutaneous cryotherapy. There were 73 males and 48 females, mean age 60 years. Of the 121 patients, 61 patients had cryoablation under CT guidance and 60 patients under the guidance of MRI. CT-guidance was performed with the Philips big-bore CT in spiral mode, with 5 mm slice thickness. The MR guidance was performed with GE 0.35 T scanner assisted with infrared navigator (Xinaomdt), and both fast gradient echo sequence and fast spin-echo sequence were used. The cryoablation system is a magnetic resonance compatible system (Galil, Israel), equipped with 17 G cryoprobes that are 1.47 mm in outside diameter. A combination of multiple cryo-probes and conformal cryoablation were adopted in accordance with the location, the shape and the adjacent structure of each lesion. Each cryoablation included two freezing-thawing cycles. Scanning was performed intermittently during the operation to monitor the degree of ablation. The mean scanning time, the lesion depiction and ablation process monitoring, the efficacies of lesion ablation, complications,and survival time were analyzed with χ 2 test. Results: The mean scanning time was (5.6±1.8) min for CT and (22.0±2.6) min for MR. CT provided a good depiction of the lesion and the ribs which were poorly displayed on MR images. The metal probe could create artifacts on the CT images and it was difficult for CT to show the formation of ice ball of the lesion formed after embolization with lipiodol. MR was superior to CT in displaying, guiding and monitoring of ablation of lesions near such special regions as the diaphragm dome, the hepatic hilum, and the gallbladder. MR was not affected by high-density embolization material and the metal probes, and thus was superior to CT in depicting the lesion, and monitoring the

Hypervascular hepatocellular carcinomas: detection with gadoxetate disodium-enhanced MR imaging and multiphasic multidetector CT

Energy Technology Data Exchange (ETDEWEB)

Onishi, Hiromitsu; Kim, Tonsok; Hori, Masatoshi; Nakaya, Yasuhiro; Tsuboyama, Takahiro; Nakamoto, Atsushi; Tatsumi, Mitsuaki; Tomiyama, Noriyuki [Osaka University Graduate School of Medicine, Department of Radiology, Suita, Osaka (Japan); Imai, Yasuharu [Ikeda Municipal Hospital, Department of Gastroenterology, Ikeda, Osaka (Japan); Nagano, Hiroaki [Osaka University Graduate School of Medicine, Department of Surgery, Suita, Osaka (Japan); Kumano, Seishi; Okada, Masahiro; Murakami, Takamichi [Kinki University School of Medicine, Department of Radiology, Osakasayama, Osaka (Japan); Takamura, Manabu [Ikeda Municipal Hospital, Department of Radiology, Ikeda, Osaka (Japan); Wakasa, Kenichi [Osaka City University Graduate School of Medicine, Department of Diagnostic Pathology, Osaka, Osaka (Japan)

2012-04-15

To retrospectively compare the accuracy of detection of hypervascular hepatocellular carcinoma (HCC) by multiphasic multidetector CT and by gadoxetate disodium-enhanced MR imaging. After ethical approval, we analysed a total of 73 hypervascular HCC lesions from 31 patients suspected of having HCC, who underwent both gadoxetate disodium-enhanced MR imaging and multiphasic multidetector CT. Five blinded observers independently reviewed CT images, as well as dynamic MR images alone and combined with hepatobiliary phase MR images. Diagnostic accuracy (Az values), sensitivities and positive predictive values were compared by using the Scheffe post hoc test. The mean Az value for dynamic and hepatobiliary phase MR combined (0.81) or dynamic MR images alone (0.78) was significantly higher than that for CT images (0.67, P < 0.001, 0.005, respectively). The mean sensitivity of the combined MR images (0.67) was significantly higher than that of dynamic MR alone (0.52, P < 0.05) or CT images (0.44, P < 0.05). The mean positive predictive values were 0.96, 0.95 and 0.94, for CT, dynamic MR alone and combined MR images, respectively. Compared with multiphasic multidetector CT, gadoxetate disodium-enhanced MR imaging combining dynamic and hepatobiliary phase images results in significantly improved sensitivity and diagnostic accuracy for detection of hypervascular HCC. (orig.)

Imaging diagnostics of the wrist: MRI and Arthrography/Arthro-CT; Bildgebende Diagnostik des Handgelenkes: MRT und Arthrographie/Arthro-CT

Energy Technology Data Exchange (ETDEWEB)

Klein, H.M.; Balas, R.; Neugebauer, F. [Radiologische Gemeinschaftspraxis, Betzdorf (Germany); Vrsalovic, V. [Handchirugie, Marienhospital Siegen, Siegen (Germany)

2002-02-01

Purpose: To evaluate the use of magnetic resonance imaging (MRI) compared with arthrography and arthro-CT (AG/ACT) in patients with wrist pain. Methods: MRI and arthrography/arthro-CT (AG/ACT) of the wrist joint were retrospectively evaluated in 346 patients over a three-year period. Imaging findings were correlated to surgical results (n=78) or clinical course in an at least 6-month follow-up. Results: For tears of the triangular fibrocartilage, arthrography, arthro-CT, and MRI demonstrated a sensitivity and specificity of more than 0.96. Only the positive predictive value was superior for arthrography/arthro-CT (0.99 and 0.98, respectively) compared with MRI (0.94). Arthrography was superior for functional diagnosis of scapho-lunate ligament tears (n=25). Ulno-lunate and ulno-triquetral ligament defects were demonstrated more exactly by arthrography. Traumatic osseous defects, particularly scaphoid fractures (n=33) and avascular necrosis (n=17), were better diagnosed using MRI. Conclusion: For suspected lesions of the triangular fibrocartilage complex, AG/ACT is slightly more reliable than MRI. However, MRI was found to be highly accurate in diagnosing TFC tears, and is superior to AG/ACT in detecting traumatic and vascular lesions of the wrist. (orig.) [German] Ziel: Die Untersuchung der diagnostischen Aussagekraft von Magnetresonanz-Tomographie (MRT), Arthrographie (AG) und Arthro-CT (ACT) bei Erkrankungen des Handgelenkes. Methodik: Insgesamt 346 Untersuchungen des Handgelenkes wurden fuer einen dreijaehrigen Beobachtungszeitraum retrospektiv ausgewertet. Es wurden 211 MRT, 151 Arthrographien (AG) und 126 Arthro-CT (ACT) durchgefuehrt. Alle Diagnosen wurden operativ (n=78) oder durch den klinischen Verlauf in einer 6-monatigen Nachbeobachtung gesichert. Ergebnisse: Fuer die Diagnostik von Laesionen des diskoulnaren Komplexes lag die Sensitivitaet und Spezifitaet von AG, ACT und MRT ueber 0,96. Lediglich der positive Vorhersagewert differierte, allerdings nicht

Colorectal cancer staging: comparison of whole-body PET/CT and PET/MR.

Science.gov (United States)

Catalano, Onofrio A; Coutinho, Artur M; Sahani, Dushyant V; Vangel, Mark G; Gee, Michael S; Hahn, Peter F; Witzel, Thomas; Soricelli, Andrea; Salvatore, Marco; Catana, Ciprian; Mahmood, Umar; Rosen, Bruce R; Gervais, Debra

2017-04-01

Correct staging is imperative for colorectal cancer (CRC) since it influences both prognosis and management. Several imaging methods are used for this purpose, with variable performance. Positron emission tomography-magnetic resonance (PET/MR) is an innovative imaging technique recently employed for clinical application. The present study was undertaken to compare the staging accuracy of whole-body positron emission tomography-computed tomography (PET/CT) with whole-body PET/MR in patients with both newly diagnosed and treated colorectal cancer. Twenty-six patients, who underwent same day whole-body (WB) PET/CT and WB-PET/MR, were evaluated. PET/CT and PET/MR studies were interpreted by consensus by a radiologist and a nuclear medicine physician. Correlations with prior imaging and follow-up studies were used as the reference standard. Correct staging was compared between methods using McNemar's Chi square test. The two methods were in agreement and correct for 18/26 (69%) patients, and in agreement and incorrect for one patient (3.8%). PET/MR and PET/CT stages for the remaining 7/26 patients (27%) were discordant, with PET/MR staging being correct in all seven cases. PET/MR significantly outperformed PET/CT overall for accurate staging (P = 0.02). PET/MR outperformed PET/CT in CRC staging. PET/MR might allow accurate local and distant staging of CRC patients during both at the time of diagnosis and during follow-up.

CT and MR features of the intracranial Schwannomas

International Nuclear Information System (INIS)

Jung, So Lyung; Ro, Hee Jeong; Lee, Hong Jae; Jung, Seung Eun; Byun, Jae Young; Yang, Il Kwon; Lee, Han Jin; Choi, Kyu Ho; Kim, Jong Woo; Shinn, Kyung Sub

1996-01-01

To evaluate CT and MR findings of the intracranial schwannomas arising from variable cranial nerves. The authors retrospectively analyzed CT (n=21) and MR (n=15) findings of 24 cases in 23 patients (M : 7, F : 16) who had suffered from surgically-proven intracranial schwannomas over the previous five years. Schwannomas arose from the acoustic nerve(n=18), the trigeminal nerve(n=2), the glossopha-ryngeal-vagal-accessory nerve complex (n=2), and the olfactory nerve(n=1). Intracranial schwannomas were well defined, ,lobulated and inhomogeneously or homogeneously enhancing masses on CT and MR, and were located along the course of the specific cranial nerve. Acoustic schwannomas involved both the internal auditory canal(IAC) and the cerebellopontive angle(CPA) in 14 case, the IAC in three, and the SPA in two. Two trigeminal schwannomas involved both middle and posterior cranial fossa and were in the shape of a dumbbell. One of the two schwannomas that invelved lower cranial nerve complex(9-11th) was located in the medullary cistern and jugular foramen ; the other was located in the central posterior cranial fossa. A case of olfactory schwannoma was located in the right cribriform plate. The precontrast CT scan showed low density in 13 cases (62%), isodensity in seven(33%) and high density in one(5%). on postcontrast CT scan, enhancement was seen in 20 cases(95%). Of the 15 cases with MR, 2 had low signal intensity on T1 weighted image and 14 had high signal intensity on T2 weighted image. MR imaging after Gd-DTPA infusion showed enhancement in 14 cases. Enhancement was inhomogeneous in 14 cases on CT and in 13 on MR. Of 24 cases, intratumoral necrosis was seen in 19, ring enhancement in five and severe cystic change in one. Other findings were in tratumoral calcification (21%), hemorrhage(8%), pressure bony erosion(70.8%), midline shift(58%), peritumoral edema(29%) and hydrocephalus(33%). On MR, there was in all 15 cases a peritumoral low signal intensity rim on T1-and

Quantitative comparison of PET performance—Siemens Biograph mCT and mMR

Energy Technology Data Exchange (ETDEWEB)

Karlberg, Anna M.; Sæther, Oddbjørn [Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Olav Kyrres gt 17, 7006 Trondheim (Norway); Eikenes, Live [Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Postbox 8905, 7491 Trondheim (Norway); Goa, Pål Erik [Department of Radiology and Nuclear Medicine, St. Olavs Hospital, Olav Kyrres gt 17, 7006 Trondheim (Norway); Department of Physics, Norwegian University of Science and Technology, Trondheim (Norway)

2016-02-25

Integrated clinical whole-body PET/MR systems were introduced in 2010. In order to bring this technology into clinical usage, it is of great importance to compare the performance with the well-established PET/CT. The aim of this study was to evaluate PET performance, with focus on image quality, on Siemens Biograph mMR (PET/MR) and Siemens Biograph mCT (PET/CT). A direct quantitative comparison of the performance characteristics between the mMR and mCT system was performed according to National Electrical Manufacturers Association (NEMA) NU 2-2007 protocol. Spatial resolution, sensitivity, count rate and image quality were evaluated. The evaluation was supplemented with additional standardized uptake value (SUV) measurements. The spatial resolution was similar for the two systems. Average sensitivity was higher for the mMR (13.3 kcps/MBq) compared to the mCT system (10.0 kcps/MBq). Peak noise equivalent count rate (NECR) was slightly higher for the mMR (196 kcps @ 24.4 kBq/mL) compared to the mCT (186 kcps @ 30.1 kBq/mL). Scatter fractions in the clinical activity concentration range yielded lower values for the mCT (34.9 %) compared to those for the mMR (37.0 %). Best image quality of the systems resulted in approximately the same mean hot sphere contrast and a difference of 19 percentage points (pp) in mean cold contrast, in favour of the mCT. In general, point spread function (PSF) increased hot contrast and time of flight (TOF) increased both hot and cold contrast. Highest hot contrast for the smallest sphere (10 mm) was achieved with the combination of TOF and PSF on the mCT. Lung residual error was higher for the mMR (22 %) than that for the mCT (17 %), with no effect of PSF. With TOF, lung residual error was reduced to 8 % (mCT). SUV was accurate for both systems, but PSF caused overestimations for the 13-, 17- and 22-mm spheres. Both systems proved good performance characteristics, and the PET image quality of the mMR was close to that of the mCT

Detection and staging of chondromalacia patellae: relative efficacies of conventional MR imaging, MR arthrography, and CT arthrography.

Science.gov (United States)

Gagliardi, J A; Chung, E M; Chandnani, V P; Kesling, K L; Christensen, K P; Null, R N; Radvany, M G; Hansen, M F

1994-09-01

Chondromalacia patellae is a condition characterized by softening, fraying, and ulceration of patellar articular cartilage. We compare the sensitivity, specificity, and accuracy of conventional MR imaging, MR arthrography, and CT arthrography in detecting and staging this abnormality. Twenty-seven patients with pain in the anterior part of the knee were prospectively examined with MR imaging, including T1-weighted (650/16), proton density-weighted (2000/20), T2-weighted (2000/80), and spoiled two-dimensional gradient-recalled acquisition in the steady state (SPGR/)/35 degrees (51/10) with fat saturation pulse sequences. All were also examined with T1-weighted MR imaging after intraarticular injection of dilute gadopentetate dimeglumine and with double-contrast CT arthrography. Each imaging technique was evaluated independently by two observers, who reached a consensus interpretation. The signal characteristics of cartilage on MR images and contour abnormalities noted with all imaging techniques were evaluated and graded according to a modification of the classification of Shahriaree. Twenty-six of the 54 facets examined had chondromalacia shown by arthroscopy, which was used as the standard of reference. The sensitivity, specificity, and accuracy of each imaging technique in the diagnosis of each stage of chondromalacia patellae were determined and compared by using the McNemar two-tailed analysis. Arthroscopy showed that 28 facets were normal. Grade 1 chondromalacia patellae was diagnosed only with MR and CT arthrography in two (29%) of seven facets. Intermediate (grade 2 or 3) chondromalacia patellae was detected in two (13%) of 15 facets with T1-weighted and SPGR MR imaging, in three (20%) of 15 facets with proton density-weighted MR imaging, in seven (47%) of 15 facets with T2-weighted MR imaging, in 11 (73%) of 15 facets with CT arthrography, and in 12 (80%) of 15 facets with MR arthrography. Grade 4 was detected in three (75%) of four facets with T1-, proton

Volume-artifact reduction modality by helical CT of the anterior, middle and posterior carnial fossae. Comparison with conventional CT; Volumen-Artefakt-Reduktionstechnik mittels Spiral-CT in der vorderen, mittleren und hinteren Schaedelgrube. Vergleich mit der konventionellen kranialen CT

Energy Technology Data Exchange (ETDEWEB)

Dorenbeck, U.; Finkenzeller, T.; Hill, K.; Feuerbach, S.; Link, J. [Regensburg Univ. (Germany). Inst. fuer Roentgendiagnostik

2000-04-01

Purpose: The object of this study was to determine the extent to which a new volume-artifact reduction (VAR) modality using helical CT was able to reduce artifacts in the anterior, middle and posterior fossae in comparison with conventional CT (sequential mode). Methods: In a prospective, randomized trial, 50 patients underwent helical CT (VAR) and 50 underwent sequential CT. The results were evaluated by three radiologists; influences on image quality where scaled between 1 (no artifact) and 4 (not assessable). Eight regions of the anterior, middle and posterior fossae were evaluated. Results: On average, artifacts were scaled at 2.5 in helical CT (VAR) and 3.1 in conventional CT. Significant differences were seen at the eyeball, anterior to the petrosol bone, at the internal occipital crest, and at the level of the transverse sinus (p<0.005). Conclusions: Helical CT with the VAR modality is superior to conventional, sequential CT in the area of the anterior, middle and posterior fossae. (orig.) [German] Ziel: Das Ziel dieser Studie war herauszufinden, inwieweit ein neuer Volumen-Artefakt-Reduktionsmodus (VAR) im Spiral-CT in der vorderen, mittleren und hinteren Schaedelgrube gegenueber der Einzelschicht-CT zu einer Artefaktverringerung beitragen kann. Methoden: In einer prospektiven randomisierten Studie wurden 50 Untersuchungen mit Spiral-CT und 50 mit Einzelschicht-CT bezueglich Artefakten verglichen. Die Auswertung erfolgte durch drei Radiologen, die Bildqualitaet wurde in einer Skala zwischen 1 (kein Artefakt) und 4 (Beurteilung der Region wegen Artefakten nicht moeglich) angegeben. Acht anatomische Regionen in der vorderen, mittleren und hinteren Schaedelgrube wurden auf Beeintraechtigung durch Artefakte untersucht. Ergebnisse: Im Durchschnitt betrug die Bewertung fuer die Artefaktbeeintraechtigung beim Spiral-CT (VAR) 2,5 gegenueber 3,1 bei der Einzelschicht-CT. Der VAR-Modus ermoeglichte in der mittleren und hinteren Schaedelgrube sowie im Balbus oculi

Comparison of MultiHance {sup trademark} and Gadovist {sup trademark} for cerebral MR perfusion imaging in healthy volunteers; Vergleich von MultiHance {sup trademark} und Gadovist {sup trademark} zur zerebralen MR-Perfusionsmessung bei gesunden Probanden

Energy Technology Data Exchange (ETDEWEB)

Essig, M.; LeHuu, M.; Huebener, M.; Kaick, G. van [Deutsches Krebsforschungszentrum, Abt. Radiologische Diagnostik und Therapie, Heidelberg (Germany); Lodemann, K.P. [Bracco-Byk, Gulden (Germany); Schoenberg, S.O. [Institut fuer Klinische Radiologie, Ludwig-Maximilians-Universitaet Muenchen, Grosshadern (Germany)

2002-11-01

To evaluate the weakly protein interacting MR contrast agent MultiHance {sup trademark} and the one-molar agent Gadovist {sup trademark} for cerebral perfusion MR imaging, a randomized intraindividual study was conducted in 12 healthy male volunteers. Perfusion-MRI was performed with single and double dose of each contrast agent on a 1.5T MR system using a gradient-echo EPI sequence. The imaging parameters, slice positioning and contrast media application were standardized. For the quantitative assessment rCBV and rCBF measurements of gray and white matter were performed. Additionally, the percentage of signal drop and the full width half maximum (FWHM) of ROI signal time curves were quantified. In a qualitative analysis the image quality of the rCBV and rCBF maps were assessed.Single dosage of the used new contrast agents was sufficient to achieve high quality perfusion maps. The susceptibility effect, described by percentage of signal loss (Gadovist {sup trademark} : 29.4% vs. MultiHance {sup trademark} : 28.3%) and the FWHM (Gadovist {sup trademark} : 6.4 s vs. Multihance {sup trademark} : 7.0 s) were not different between the agents for single dose.The one molar MR contrast agent Gadovist {sup trademark} has no advantages over MultiHance {sup trademark}, a MR contrast agent with a higher relaxivity in perfusion MRI. Both agents allow the calculation of high quality perfusion maps at a dosage of 0.1 mmol/kg bw with physiologic absolute values for regional CBV and CBF. The susceptibility effect is comparable for both agents and stronger than with conventional MR contrast media. (orig.) [German] Zur Evaluierung des gering proteinbindenden MR-Kontrastmittels MultiHance {sup trademark} und des einmolaren MR-Kontrastmittels Gadovist {sup trademark} fuer die MR-Perfusionsmessung im Gehirn wurden in einer randomisierten, intraindividuellen Vergleichsstudie 12 gesunde maennliche Probanden untersucht. Die Perfusionsmessung wurde an einem 1,5-T-MRT mit einer T2

Paroxysmal nocturnal hemoglobinuria: a case report of MR, CT findings

International Nuclear Information System (INIS)

Yang, Ik; Chung, Soo Young; Park, Hai Jung; Lee Yul; Chun, Rho Won; Noh, Jung Woo

1995-01-01

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired disease involving multiple hematopoietic cell lines. Characteristics of PNH are intrinsic hemolytic anemia, iron deficiency anemia and venous thrombosis. We report a case of PNH with characterostoc MR and CT findings. The signal intensity of renal cortex was lower than that of medulla on both T1-and T2-weighted MR imaging. On T2 weighted MR images, the liver showed very low signal intensity but the signal intensity of the spleen was normal. On precontrast CT the attenuation of renal cortex was higher than that of renal medulla and the attenuation of liver was higher than that of the spleen. These findings of MR imaging and CT were the result from the deposition of hemosiderin in the cells of proximal convoluted tubules and transfusional hemosiderosis of liver

CT and MR imaging of the liver. Clinical importance of nutritional status

International Nuclear Information System (INIS)

Leander, P.; Sjoeberg, S.; Hoeglund, P.

2000-01-01

Purpose: In an experimental study in rats a correlation between nutritional status and hepatic attenuation in CT and signal intensities in MR imaging was shown. Is physiological nutritional status of importance in clinical CT and MR imaging? Material and methods: In a cross-over study including 12 healthy volunteers (6 women and 6 men, mean age 34 years), CT and MR imaging of the liver were performed with nutritional status at three different levels, i.e., normal, fasting and after glycogen-rich meals. CT and MR were performed on clinical imaging systems and hepatic attenuation and signal intensity, respectively, were assessed. In MR, T1-weighted, proton density-weighted and T2-weighted pulse-sequences were used. Results: In CT there were significantly (p<0.01) higher liver attenuations in normal nutritional status and after glycogen rich-meals compared to the fasting condition. The difference between fasting and glycogen-rich meals were 10.5 HU for men, 7.4 for women and mean 8.8 HU for all 12 volunteers. In MR imaging the differences were small and non-significant. The results of this study are in accordance with an earlier experimental study in rats. Conclusion: In CT it may be of importance not to have patients in a fasting condition as it lowers the attenuation in normal liver tissue. The findings are important for planning of clinical studies where hepatic attenuation will be assessed and may be of some importance in clinical CT. In MR imaging the results indicate that the nutritional status is of less importance

MR imaging of the kidneys: new diagnostic strategies; MR-Bildgebung der Nieren. Neue Ansaetze in der Diagnostik

Energy Technology Data Exchange (ETDEWEB)

Schoenberg, S.O.; Knopp, M.V.; Bock, M.; Floemer, F.; Essig, M.; Hawighorst, H.; Kaick, G. van [Deutsches Krebsforschungszentrum, Heidelberg (Germany). Forschungsschwerpunkt Radiologische Diagnostik; Kallinowski, F. [Heidelberg Univ. (Germany). Chirurgische Universitaetsklinik; Just, A. [Heidelberg Univ. (Germany). 1. Physiologisches Inst.; Laub, G. [Siemens AG, Erlangen (Germany). Unternehmensbereich Medizinische Technik; Prince, M.R [Michigan Univ., Ann Arbor, MI (United States). Dept. of Radiology

1999-05-01

Aim: New diagnostic strategies for evaluation of the kidney by fast MR imaging of renal morphology, multiphase 3D gadolinium MR angiography, MR urography and MR flow measurements. A signal MR examination is designed to grade renovascular disease and assess the hemodynamic and functional significance, detect and characterize renal lesions and evaluate the urinary tract. Results: The combined analysis of morphologic and functional data allows reliable assessment of renal artery stenosis, benign and malignant renal masses and diseases of the renal collecting system and ureters, as well as congenital abnormalities in good agreement to the results of conventional imaging modalities. The improved tissue contrast and additional functional information compensates for the disadvantage of a lower spatial resolution. Conclusion: Combined morphologic and functional MR examination represents a reliable, non-invasive and cost-effective alternative imaging modality for comprehensive diagnostic evaluation of renal disease. (orig.) [Deutsch] Fragestellung: Darstellung neuer diagnostischer Moeglichkeiten im Bereich der Niere mittels schneller Magnetresonanz (MR)-Bildgebung. Methodik: Vorgestellt wird ein kombiniertes morphologisches und funktionelles Untersuchungskonzept bestehend aus schneller morphologischer Bildgebung, multiphasischer 3D-Gadolinium-MR-Angiographie, MR-Urographie und MR-Flussmessung. In einer einzigen MR-Untersuchung sollen vaskulaere Erkrankungen erfasst, eingestuft und auf ihre haemodynamische und funktionelle Signifikanz ueberprueft werden, renale Laesionen detektiert und differenziert sowie die Harnabflusswege beurteilt werden. Ergebnisse: Durch Integration der gewonnenen morphologischen und funktionellen Daten lassen sich Nierenarterienstenosen, benigne und maligne renale Tumoren, Harnabflussstoerungen und kongenitale Fehlbildungen mit aehnlicher Genauigkeit wie in den konventionellen radiologischen Verfahren erfassen. Der Nachteil der geringeren raeumlichen

Chordoma versus chondrosarcoma of the central skull base: MR and CT findings

International Nuclear Information System (INIS)

Choi, Guk Myeong; Han, Moon Hee; Chang, Kee Hyun; Kim, Hong Dae; Yeon, Kyung Mo; Kim, Sam Soo

1998-01-01

It is known that due to both their imaging and pathologic features, the accurate differentiation of chondrosarcoma from chordoma is difficult. Through an analysis of MR and CT finding, this study aims to determine the differential points between these two tumors. In 21 patients, CT and MR imaging studies of chordoma (n=12) and chondrosarcoma (n=9) at the base of the skull were retrospectively reviewed. Diagnosis had been established by histologic examination of surgically removed specimens. Eleven of the chordomas were subclassified as conventional and one as chondroid ; eight chondrosarcoma were conventional and one was myxoid. Four chordoma patients underwent CT and MR ; in six, only MR was in one, only CT was performed. All scans were retrospectively evaluated for the location (midline/off-midline), direction of extension, margin and shape, bony destruction and calcification, MR signal intensity and enhancement patterns of the tumors. Degree of calcification was graded from I to II. Although MR and CT findings were similar in both types of tumor, location and degree of calcification may be features which usefully distinguish chordoma from chondrosarcoma. (author). 17 refs., 2 tabs., 5 figs

Cochlear anatomy: CT and MR imaging

International Nuclear Information System (INIS)

Martinez, Manuel; Bruno, Claudio; Martin, Eduardo; Canale, Nancy; De Luca, Laura; Spina, Juan C. h

2002-01-01

The authors present a brief overview of the normal cochlear anatomy with CT and MR images in order to allow a more complete identification of the pathological findings in patients with perceptive hipoacusia. (author)

Comparison of MR imaging and CT in the evaluation of uterine tumors

International Nuclear Information System (INIS)

Janus, C.L.; Dottino, P.; Brodman, M.; Goodman, H.; Gendal, E.S.; Rabinowitz, J.G.

1987-01-01

The authors compared the usefulness of MR imaging and CT in staging uterine tumors. Forty women with known cervical carcinoma, endometrial cancer, or leiomyosarcoma underwent CT and MR imaging within 1 week prior to surgery. MR imaging was better than CT for localizing tumors to the endometrium of myometrium and in the evaluation of lymph node involvement and extension to the cervix and parametria. MR imaging, with its superior ability to demonstrate pelvic anatomy and its lack of ionizing radiation and risk from iodinated contrast media, has an important place in the staging of uterine tumors

MR imaging versus PET/CT for evaluation of pancreatic lesions

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Belião, Sara, E-mail: sara.beliao@clix.pt [Department of Radiology Hospital S. Francisco Xavier, Estrada do Forte do Alto do Duque, 1495-005 Lisbon (Portugal); Ferreira, Alexandra, E-mail: alexandratavaresferreira@gmail.com [Department of Radiology, Hospital D. Estefânia, Rua Jacinta Marto, 1169-045 Lisbon (Portugal); Vierasu, Irina, E-mail: Ortansa-Irina.Vierasu@ulb.ac.be [Service de Médecine Nucléaire, Route de Lennik 808, 1070 Brussels (Belgium); Blocklet, Didier, E-mail: dblockle@ulb.ac.be [Service de Médecine Nucléaire, Route de Lennik 808, 1070 Brussels (Belgium); Goldman, Serge, E-mail: petscan@ulb.ac.be [Service de Médecine Nucléaire, Route de Lennik 808, 1070 Brussels (Belgium); Metens, Thierry, E-mail: tmetens@ulb.ac.be [Service de Radiologie – Imagerie par Resonance Magnétique, Route de Lennik 808, 1070 Brussels (Belgium); Matos, Celso, E-mail: cmatos@ulb.ac.be [Service de Radiologie – Imagerie par Resonance Magnétique, Route de Lennik 808, 1070 Brussels (Belgium)

2012-10-15

Purpose: To retrospectively determine the diagnostic accuracy of magnetic resonance imaging (MRI) and combined positron emission tomography/computed tomography (PET/CT) in the differential diagnosis of benign and malignant pancreatic lesions. Materials and methods: Twenty-seven patients (15 women/12 men, mean age 56.5 years) with MR imaging and PET/CT studies performed to differentiate benign and malignant pancreatic lesions were identified between October 2008 and October 2010. Both MR and PET/CT data sets were retrospectively and blindly evaluated by two independent readers (4 readers total) with different degrees of experience, using a visual five-point score system. The results were correlated with final diagnosis obtained by histopathology. Results: 17 patients had malignant diseases and 10 patients had benign diseases. Depending on the observer, the sensitivity, specificity, positive predictive value and negative predictive value of MRI varied between 88–94%, 50–80%, 75–89% and 71–89% respectively. Sensitivities, specificities, positive predictive values and negative predictive values of PET/CT were 73%, 56%, 73% and 56% respectively. The diagnostic accuracy of MR for the differential diagnosis of pancreatic lesions was 74–89%, compared with 67% for PET/CT. The weighted Cohen's kappa coefficient was 0.47 at MR and 0.53 at PET/CT. Conclusion: MRI achieved higher sensitivity and specificity in the differential diagnosis of pancreatic lesions.

Three-dimensional CT and MR imaging in congenital dislocation of the hip: Technical considerations

International Nuclear Information System (INIS)

Lang, P.; Steiger, P.; Lindquist, T.; Skinner, S.; Moore, S.; Chafetz, N.I.; Genant, H.K.

1987-01-01

Two-dimensional (2D) software techniques were developed to generate diagnostic-quality three-dimensional (3D) MR studies in two patients with congenital dislocation of the hip. Comparable 3D CT studies were obtained in two other patients. Unsharp masks were divided into the original MR images to correct for local variations in signal intensity. Combinations of first- and second-echo images improved the object contrast. Pixels with insufficient homogeneity relative to their neighboring data were excluded. CT did not require 2D preprocessing. Three-dimensional CT and MR images demonstrated subluxation and dislocation. 3D MR, in contrast to CT, demonstrated the cartilaginous femoral head. The described 2D MR preprocessing provides diagnostic-quality 3D MR studies. It will be useful for generating 3D MR images of other anatomic structures

Castleman disease of the neck: CT and MR imaging findings

International Nuclear Information System (INIS)

Jiang, Xin-hua; Song, Hao-ming; Liu, Qing-yu; Cao, Yun; Li, Guo-hong; Zhang, Wei-dong

2014-01-01

Objective: To characterize the computed tomography (CT) and magnetic resonance imaging (MRI) findings of Castleman disease of the neck. Methods: The imaging findings of 21 patients with Castleman disease of the neck were reviewed retrospectively. Of the 21 patients, 16 underwent unenhanced and contrast-enhanced CT scans; 5 underwent unenhanced and contrast-enhanced MRI scans. Results: The unenhanced CT images showed isolated or multiple well-defined homogenous mild hypodensity lesions in fifteen cases, and a heterogeneous nodule with central areas of mild hypodensity in one case. Calcification was not observed in any of the patients. In five patients, MR T1-weighted images revealed well-defined, homogeneous isointense or mild hyperintense lesions to the muscle; T2-weighted images showed these as intermediate hyperintense. Sixteen cases showed intermediate to marked homogeneous enhancement on contrast-enhanced CT or MR T1-weighted images. Of the other five cases that underwent double-phase CT scans, four showed mild or intermediate heterogeneous enhancement at the arterial phase, and homogeneous intermediate or marked enhancement at the venous phase; the remaining case showed mild and intermediate ring-enhancement with a central non-enhanced area at the arterial and venous phases, respectively. Conclusion: Castleman disease of the neck can be characterized as solitary or multiple well-defined, mild hypodensity or homogeneous intense lesions on plain CT/MR scans, and demonstrates intermediate and marked enhancement on contrast-enhanced CT/MR scans. On double-phase CT scans, Castleman disease often demonstrates mild enhancement at the arterial phase, and gradually uniform enhancement at venous phase. Double-phase enhanced CT or MRI may help to differentiate Castleman disease from other diseases

Castleman disease of the neck: CT and MR imaging findings

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Jiang, Xin-hua [Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060 (China); Song, Hao-ming [Department of Cardiology, Shanghai Tongji Hospital, Shanghai 200065 (China); Liu, Qing-yu [Department of Radiology, The Second Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120 (China); Cao, Yun [Department of Pathology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060 (China); Li, Guo-hong [Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060 (China); Zhang, Wei-dong, E-mail: dongw.z@163.com [Department of Radiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong 510060 (China)

2014-11-15

Objective: To characterize the computed tomography (CT) and magnetic resonance imaging (MRI) findings of Castleman disease of the neck. Methods: The imaging findings of 21 patients with Castleman disease of the neck were reviewed retrospectively. Of the 21 patients, 16 underwent unenhanced and contrast-enhanced CT scans; 5 underwent unenhanced and contrast-enhanced MRI scans. Results: The unenhanced CT images showed isolated or multiple well-defined homogenous mild hypodensity lesions in fifteen cases, and a heterogeneous nodule with central areas of mild hypodensity in one case. Calcification was not observed in any of the patients. In five patients, MR T1-weighted images revealed well-defined, homogeneous isointense or mild hyperintense lesions to the muscle; T2-weighted images showed these as intermediate hyperintense. Sixteen cases showed intermediate to marked homogeneous enhancement on contrast-enhanced CT or MR T1-weighted images. Of the other five cases that underwent double-phase CT scans, four showed mild or intermediate heterogeneous enhancement at the arterial phase, and homogeneous intermediate or marked enhancement at the venous phase; the remaining case showed mild and intermediate ring-enhancement with a central non-enhanced area at the arterial and venous phases, respectively. Conclusion: Castleman disease of the neck can be characterized as solitary or multiple well-defined, mild hypodensity or homogeneous intense lesions on plain CT/MR scans, and demonstrates intermediate and marked enhancement on contrast-enhanced CT/MR scans. On double-phase CT scans, Castleman disease often demonstrates mild enhancement at the arterial phase, and gradually uniform enhancement at venous phase. Double-phase enhanced CT or MRI may help to differentiate Castleman disease from other diseases.

Radiation therapy treatment planning: CT, MR imaging and three-dimensional planning

International Nuclear Information System (INIS)

Lichter, A.S.

1987-01-01

The accuracy and sophistication of radiation therapy treatment planning have increased rapidly in the last decade. Currently, CT-based treatment planning is standard throughout the country. Care must be taken when CT is used for treatment planning because of clear differences between diagnostic scans and scans intended for therapeutic management. The use of CT in radiation therapy planning is discussed and illustrated. MR imaging adds another dimension to treatment planning. The ability to use MR imaging directly in treatment planning involves an additional complex set of capabilities from a treatment planning system. The ability to unwarp the geometrically distorted MR image is a first step. Three-dimensional dose calculations are important to display the dose on sagittal and acoronal sections. The ability to integrate the MR and CT images into a unified radiographic image is critical. CT and MR images are two-dimensional representations of a three-dimensional problem. Through sophisticated computer graphics techniques, radiation therapists are now able to integrate a three-dimensional image of the patient into the treatment planning process. This allows the use of noncoplanar treatment plans and a detailed analysis of tumor and normal tissue anatomy; it is the first step toward a fully conformational treatment planning system. These concepts are illustrated and future research goals outlined

Prediction of CT Substitutes from MR Images Based on Local Diffeomorphic Mapping for Brain PET Attenuation Correction.

Science.gov (United States)

Wu, Yao; Yang, Wei; Lu, Lijun; Lu, Zhentai; Zhong, Liming; Huang, Meiyan; Feng, Yanqiu; Feng, Qianjin; Chen, Wufan

2016-10-01

Attenuation correction is important for PET reconstruction. In PET/MR, MR intensities are not directly related to attenuation coefficients that are needed in PET imaging. The attenuation coefficient map can be derived from CT images. Therefore, prediction of CT substitutes from MR images is desired for attenuation correction in PET/MR. This study presents a patch-based method for CT prediction from MR images, generating attenuation maps for PET reconstruction. Because no global relation exists between MR and CT intensities, we propose local diffeomorphic mapping (LDM) for CT prediction. In LDM, we assume that MR and CT patches are located on 2 nonlinear manifolds, and the mapping from the MR manifold to the CT manifold approximates a diffeomorphism under a local constraint. Locality is important in LDM and is constrained by the following techniques. The first is local dictionary construction, wherein, for each patch in the testing MR image, a local search window is used to extract patches from training MR/CT pairs to construct MR and CT dictionaries. The k-nearest neighbors and an outlier detection strategy are then used to constrain the locality in MR and CT dictionaries. Second is local linear representation, wherein, local anchor embedding is used to solve MR dictionary coefficients when representing the MR testing sample. Under these local constraints, dictionary coefficients are linearly transferred from the MR manifold to the CT manifold and used to combine CT training samples to generate CT predictions. Our dataset contains 13 healthy subjects, each with T1- and T2-weighted MR and CT brain images. This method provides CT predictions with a mean absolute error of 110.1 Hounsfield units, Pearson linear correlation of 0.82, peak signal-to-noise ratio of 24.81 dB, and Dice in bone regions of 0.84 as compared with real CTs. CT substitute-based PET reconstruction has a regression slope of 1.0084 and R 2 of 0.9903 compared with real CT-based PET. In this method, no

Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests.

Science.gov (United States)

Demir, Mustafa; Toklu, Türkay; Abuqbeitah, Mohammad; Çetin, Hüseyin; Sezgin, H Sezer; Yeyin, Nami; Sönmezoğlu, Kerim

2018-02-01

The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated aspects were spatial resolution, sensitivity, scatter fraction, count rate performance, image quality, count loss and random events correction accuracy. The findings of this study demonstrated superior sensitivity (~ 4 folds) of PET scanner in PET/MR compared to PET/CT system. Image quality test exhibited higher contrast in PET/MR (~ 9%) compared with PET/CT. The scatter fraction of PET/MR was 43.4% at noise equivalent count rate (NECR) peak of 218 kcps and the corresponding activity concentration was 17.7 kBq/cc. Whereas the scatter fraction of PET/CT was found as 39.2% at NECR peak of 72 kcps and activity concentration of 24.3 kBq/cc. The percentage error of the random event correction accuracy was 3.4% and 3.1% in PET/MR and PET/CT, respectively. It was concluded that PET/MR system is about 4 times more sensitive than PET/CT, and the contrast of hot lesions in PET/MR was ~ 9% higher than PET/CT. These outcomes also emphasize the possibility to achieve excellent clinical PET images with low administered dose and/or a short acquisition time in PET/MR.

Combined functional and morphological imaging of sarcomas. Significance for diagnostics and therapy monitoring; Kombinierte funktionelle und morphologische Bildgebung bei Sarkomen. Stellenwert fuer Diagnostik und Therapiemonitoring

Energy Technology Data Exchange (ETDEWEB)

Schramm, N.; Rist, C.; Reiser, M.F.; Berger, F. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany); Schlemmer, M.; Issels, R. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Medizinische Klinik und Poliklinik III, Muenchen (Germany)

2010-04-15

{sup 18}F-fluorodeoxyglucose positron-emission tomography (FDG-PET) and especially hybrid FDG-PET/CT is becoming more and more accepted for the clinical management of adult and pediatric patients with sarcomas. By integrating the CT component the specificity in particular but also the sensitivity of the modality are improved further. With PET/CT a complete staging including the detection of lung metastases is feasible in a single examination. For patients with primary bone and soft tissue sarcomas FDG-PET/CT is utilized for diagnosis, staging and restaging, metabolic tumor grading, guidance of biopsies, detection of tumor recurrence and therapy monitoring. Furthermore, it has been demonstrated that FDG uptake of the tumor prior to treatment and changes of FDG uptake after therapy significantly correlate with histopathologic response and survival of patients. Therefore, PET and PET/CT have a prognostic value. In the future new perspectives of hybrid PET/CT imaging will arise by introducing novel radiotracers and combined functional imaging of tumor metabolism and perfusion. High resolution MRI is essential for local evaluation of the primary tumor and preoperative planning with assessment of possible infiltration of vascular or neural structures. Contrast-enhanced MRI remains a key tool in the diagnosis of recurrent disease, especially in tumors which are not hypermetabolic. Dynamic contrast-enhanced MR sequences can significantly contribute to therapy monitoring. More research is necessary to prospectively compare dynamic contrast-enhanced MRI and FDG-PET/CT for evaluation of local and recurrent diseases. (orig.) [German] Die {sup 18}F-Fluordeoxyglukose-Positronenemissionstomographie (FDG-PET) und insbesondere die Hybridbildgebung als FDG-PET/CT gewinnen beim klinischen Management erwachsener und paediatrischer Sarkompatienten zunehmend an Bedeutung. Durch die CT-Komponente werden v. a. die Spezifitaet, aber auch die Sensitivitaet des Verfahrens weiter gesteigert

MR imaging of articular cartilage; Gelenkknorpel in der MR-Tomographie

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Schaefer, F.K.W.; Muhle, C.; Heller, M.; Brossmann, J. [Kiel Univ. (Germany). Klinik fuer Diagnostische Radiologie

2001-04-01

MR imaging has evolved to the best non-invasive method for the evaluation of articular cartilage. MR imaging helps to understand the structure and physiology of cartilage, and to diagnose cartilage lesions. Numerous studies have shown high accuracy and reliability concerning detection of cartilage lesions and early changes in both structure and biochemistry. High contrast-to-noise ratio and high spatial resolution are essential for analysis of articular cartilage. Fat-suppressed 3D-T{sub 1} weighted gradient echo and T{sub 2}-weighted fast spin echo sequences with or without fat suppression are recommended for clinical routine. In this article the anatomy and pathology of hyaline articular cartilage and the complex imaging characteristics of hyaline cartilage will be discussed. (orig.) [German] Die MR-Tomographie hat sich zur besten nichtinvasiven bildgebenden Methode fuer die Untersuchung von Gelenkknorpel entwickelt. Die MR-Tomographie liefert einen Beitrag zum Verstaendnis der Knorpelstruktur und der Physiologie sowie zur Diagnostik von Knorpelschaeden. Zahlreiche MR-Studien konnten eine hohe Genauigkeit und Zuverlaessigkeit bei der Detektion chondraler Laesionen sowie frueher Veraenderungen struktureller und biochemischer Natur zeigen. Neben einem hohen Kontrast/Rausch-Verhaeltnis ist fuer die Gelenkknorpelanalyse eine hohe raeumliche Aufloesung erforderlich. Im klinischen Routinebetrieb empfehlen sich fuer die Erkennung von Knorpellaesionen besonders fettunterdrueckte 3D-T{sub 1}-gewichtete Gradientenecho- und T{sub 2}-gewichtete Fastspinecho-Sequenzen mit oder ohne Fettunterdrueckung. Die vorliegende Arbeit geht auf die Anatomie und Pathologie des hyalinen Gelenkknorpels ein und diskutiert das komplexe MR-Signalverhalten. (orig.)

Warthin's Tumor of the Parotid Gland: CT and MR Features

International Nuclear Information System (INIS)

Lee, Yun Hee; Yu, In Kyu; Lee, Byung Hee; Kim, Min Sun; Han, Moon Hee; Song, Chang Joon

2009-01-01

In this study, we have evaluated the imaging features of Warthin's tumor of the parotid gland with the use of CT and MR imaging. CT (n = 30) and MR (n = 7) images of 26 patients (M:F=23:3; age range, 38-76 years; mean age, 58 years) with surgically-proven Warthin's tumor (n = 37) were reviewed with a focus on bilaterality, multiplicity, location, size, demarcation, margin, enhancement pattern and MR signal intensity. Lesions were bilateral in seven patients (27%), multiple in nine patients (35%) and unilateral multiple in four patients (15%). Tumors were located in the superficial lobe (65%), deep lobe (24%) and both lobes (11%) of the parotid gland. Most tumors had a clear (95%) and smooth margin (95%) with a round or oval shape. Tumors mainly showed a solid and cystic composition (n = 24, 65%) and all solid stroma showed poor or weak enhancement on both CT and MR images. Papillary projections from the peripheral wall were clearly seen (n = 6, 86%). Warthin's tumor is frequently seen in the parotid superficial lobe of older males with a higher bilateral and multiple tendency. Warthin's tumor shows cystic portions with papillary projections at the wall on CT images and focal high signal intensity (SI) on T1-weighted images with dense nodular enhancement on MR images

Thoracic chordoma: CT and MR findings

International Nuclear Information System (INIS)

Cha, Yoo Mi; Hwang, Hee Young; Kim, Sang Joon; Chung, Hyo Sun; Han, Heon

1993-01-01

Chordoma arising from the notochordal remnants is a rare primary bone tumor in the cervicosacral region and is even more unusual in the thoracic region. The authors experienced a case of thoracic chordoma and reports its CT and MR findings

The role of CT and MR in diagnosis of aortic dissection

International Nuclear Information System (INIS)

Yoon, Kwon Ha; Lim, Tae Hwan; Song, Koun Sik; Min, Kyung Seok; Song, Meong Gun

1994-01-01

The purpose of this study was to determine the role of CT and MR imagings in the diagnosis of aortic dissection and differentiation between the true and false lumen. We retrospectively studied forty patients with aortic dissection(AD) diagnosed by imagings or surgery. Of the forty patients, 19 were examined with only CT, 14 with CT and MR, and 7 with MR. Our points of view were(1) the classification of AD according to configuration of intimal flap by cross-sectional imaging, (2) differentiation between the true and false lumens, (3) the course of the false lumen, and (4) detectability of the origin of major branch vessels of the abdominal aorta. The classification by cross-sectional imaging were crescentic(65%), circumferential(15%), flat(12%), and irregular(8%) type, in which false negative diagnosis was made in 1 case of crescentic and circumferential type, respectively. In 2 case of flat type and 1 case of irregular type, the differentiation between the true and false lumen was impossible with CT. The course of the false lumen in descending thoracic aorta revealed counterclock wise rotation(66%), clockwise rotation(5%) or fixed(29%) appearance. MR imaging was superior to CT in the detection of the origin of major branch vessels of the abdominal aorta. The determination of the origin of major branches of abdominal aorta arising from the true and false lumen were impossible in 2 cases in which only CT was done. Diagnosis of crescentic and circumferential types of AD with narrow and thrombosed false lumen was problematic in both CT and MR with no difference of diagnostic accuracy between the two modalities. The differentiation between the true and false lumen was difficult in flat and irregular types with only CT. Therefore, when surgical treatment is considered as in type B aortic dissection, MR imaging is recommended in order to determine the origin of major branch vessels

CT and MR findings in HIV-negative neurosyphilis

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Peng Fuhua [Department of Neurology, Third Affiliated Hospital of Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630 Guangdong Province (China)], E-mail: pfh93@21cn.com; Hu Xueqiang [Department of Neurology, Third Affiliated Hospital of Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630 Guangdong Province (China)], E-mail: huxueqiangqm@yahoo.com.cn; Zhong Xiufeng [State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center of Sun Yat-Sen University, 54 Xianlie Road, Guangzhou, 510060 Guangdong Province (China)], E-mail: xiufengzhong@yahoo.com.cn; Wei Qiu [Department of Neurology, Third Affiliated Hospital of Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630 Guangdong Province (China)], E-mail: qw9406@tom.com; Jiang Ying [Department of Neurology, Third Affiliated Hospital of Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630 Guangdong Province (China)], E-mail: jiangying722@163.com; Bao Jian [Department of Neurology, Third Affiliated Hospital of Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630 Guangdong Province (China)], E-mail: baoj92@tom.com; Wu Aimin [Department of Neurology, Third Affiliated Hospital of Sun Yat-Sen University, 600 Tianhe Road, Guangzhou, 510630 Guangdong Province (China)], E-mail: wuaim@126.com; Pei Zhong [Department of Neurology, First Affiliated Hospital of Sun Yat-Sen University, 89 Zhongshaner Road, Guangzhou, 510080 Guangdong Province (China)], E-mail: peizhong@yahoo.com

2008-04-15

Background and purpose: The purpose of this study was to describe and evaluate neuroimaging findings of patients with neurosyphilis. Methods: The neuroimaging studies of 14 patients with documented neurosyphilis were reviewed. Diagnosis was established in 14 patients with cerebrospinal fluid for a Treponema Pallidum Particle Agglutination (TPPA) test. All patients had reactive TPPA and Unheated Serum Regain test (USR) in their sera. Imaging studies included plain, contrast-enhanced CT of the brain, plain and gadolinium-enhanced MR, and MR angiography. Results: In the 14 HIV-negative patients with neurosyphilis, CT and MR showed the presence of cerebral infarction in six cases, arteritis in four cases, nonspecific white matter lesion in three cases, acute syphilitic meningitis in one case and normal neuroimaging finding in one case. In addition, 4 in 14 patients had general paresis, and MRI showed high signal intensity on T2 -weighted images involving frontotemporal lobes, hippocampus and periventricular area. Treatment with penicillin significantly diminished the size of these high signal intensity on T2-weighted images with general paresis. Conclusion: These results suggest that MR and CT images have some characteristic manifestations in patients of neurosyphilis. Because early diagnosis and treatment of neurosyphilis are crucial to avoid persistent brain damage, the neuroimaging findings are valuable adjunct to clinical diagnosis and to provide useful information to follow-up after therapy.

Recurrent postoperative sciatica: Evaluation with MR imaging and enhanced CT

International Nuclear Information System (INIS)

Duvauferrier, R.; Frocain, L.; Husson, J.L.

1987-01-01

The authors prospectively compared MR imaging performed with a surface coil and CT performed with iodinated contrast agent enhancement in 50 patients with recurrent postoperative sciatica. Surgical decision was an objective measure of accuracy. Surgical treatment was selected for 27 patients. All 27 underwent MR imaging. The 15 patients who underwent CT/surgical treatment were included in the 27 indications of SCMR. All predictions based on MR imaging findings were confirmed at surgery. There were 25 recurrent disk herniations, including five with scar tissue, and two disk herniations above or below the level of the diskectomy. In the 12 patients with scar tissue detected on CT there were seven recurrent disk hernitions, four recurrent disk herniations with scar tissue, and one disk herniation below the level of the diskectomy

CT and MR images of pleomorphic adenoma in major and minor salivary glands

International Nuclear Information System (INIS)

Kakimoto, Naoya; Gamoh, Shoko; Tamaki, Junko; Kishino, Mitsunobu; Murakami, Shumei; Furukawa, Souhei

2009-01-01

Purpose: To investigate the CT and MR imaging features of pleomorphic adenoma in the head and neck area. Materials and methods: Our materials of this study consisted of 50 pleomorphic adenomas from 50 patients which were all histopathologically diagnosed. The CT and MR images were retrospectively evaluated. The following features were evaluated: the detectability of the lesion, the tumor margin, the border of the lesion, the aspect of the lesion, the contrast between the lesion and surrounding tissue, the signal intensity of the lesion, the enhancement of contrast medium, the aspect of the lesion after the injection of contrast medium, the detectability of the capsule, and the detectability of bone resorption of the lesion. Results: The tumor detectabilities were 77% on axial plain CT images and 90% on axial CE CT images, respectively. On CT images, pleomorphic adenoma tended to show a well-defined margin, a smooth border, an inhomogeneous aspect, a low or high contrast, and intermediate or high signal intensity. After contrast medium administration, pleomorphic adenoma tended to show a slightly high enhancement and either an inhomogeneous or a periphery enhancement on the CE CT images. The capsule could be hardly detected on CT images. The tumor detectabilities were 86% on axial T1-weighted MR images, 88% on axial T2-weighted MR images, and 85% on axial CE T1-weighted MR images, respectively. On MR images, pleomorphic adenomas tended to show well-defined margin, a lobulate border, an inhomogeneous aspect, a high contrast, and intermediate or high signal intensity. After contrast medium administration, pleomorphic adenoma tended to show a high enhancement and either an inhomogeneous or a periphery enhancement on MR images. The capsule could be detected in many cases on MR images. Conclusions: It was possible to detect the capsule in pleomorphic adenoma using MR images. The pleomorphic adenomas in head and neck area should be evaluated with MR images.

Functional MRI procedures in the diagnosis of brain tumors. Perfusion- and diffusion-weighted imaging; Funktionelle MR-Verfahren in der Diagnostik intraaxialer Hirntumoren. Perfusions- und Diffusions-Bildgebung

Energy Technology Data Exchange (ETDEWEB)

Hartmann, M. [Universitaetsklinikum Heidelberg (Germany). Neurologische Klinik, Abteilung Neuroradiologie; Heiland, S.; Sartor, K.

2002-08-01

Despite the increased diagnostic accuracy of contrast material enhanced MR imaging, specification and grading of brain tumors are still only approximate at best: neither morphology, nor relaxation times or contrast material enhancement reliably predict tumor histology or tumor grade. As histology and tumor grade strongly influence which therapy concept is chosen, a more precise diagnosis is mandatory. With diffusion- and perfusion-weighted MR imaging (DWI, PWI) it is now possible to obtain important information regarding the cellular matrix and the relative regional cerebral blood volume (rrCBV) of brain tumors, which cannot be obtained with standard MR techniques. These dynamic-functional imaging techniques are very useful in the preoperative diagnosis of gliomas, lymphomas, and metastases, as well as in the differentiation of these neoplastic lesions from abscesses, atypical ischemic infarctions, and tumor-like manifestations of demyelinating disease. Additionally, they appear suitable for determining glioma grade and regions of active tumor growth which should be the target of stereotactic biopsy and therapy. After therapy these techniques are helpful to better assess the tumor response to therapy, possible therapy failure and therapy complications such as radiation necrosis. (orig.) [German] Die radiologische Diagnostik intraaxialer Hirntumoren ist durch die Magnetresonanztomographie (MRT) erheblich verbessert worden, besonders nach Einfuehrung der paramagnetischen Kontrastmittel. Mit konventionellen MR-Verfahren ist aber noch keine verlaessliche Unterscheidung zwischen Gliomen, Metastasen, primaeren Lymphomen und tumorsimulierenden entzuendlichen Erkrankungen moeglich. In dieser Hinsicht vielversprechend sind neue, funktionell-dynamische MR-Verfahren, mit denen sich nicht-invasiv die zerebrale Wasserdiffusion und Mikrozirkulation erfassen lassen und die eine bessere Gewebecharakterisierung erlauben als die herkoemmlichen MR-Methoden. Die Perfusions-MRT erfasst

Kinematic CT and MR imaging of the patellofemoral joint

International Nuclear Information System (INIS)

Muhle, C.; Brossmann, J.; Heller, M.

1999-01-01

Anterior knee pain is a frequently encountered orthopedic symptom and is often associated with patellofemoral malalignment, which may cause chondromalacia of the patella. The difficulty in determining the patellar position between 0 and 30 of knee flexion with a conventional axial radiographic examination is well known. The introduction of computed tomography (CT) and magnetic resonance (MR) imaging for the diagnosis of knee joint abnormalities has enabled assessment of the patellar position in this critical range. More recently, emphasis has been placed on dynamic visualization of patellar motion to detect an abnormal tracking pattern. The important influence of the quadriceps muscle on the patellar tracking pattern is well known and has been examined during active knee extension by the use of ultrafast CT, and motion-triggered and ultrafast MR imaging. This article provides an overview of the current status of kinematic CT and MR imaging in the diagnosis of patellofemoral alignment, its clinical implications, and future directions. (orig.)

Kinematic CT and MR imaging of the patellofemoral joint

Energy Technology Data Exchange (ETDEWEB)

Muhle, C.; Brossmann, J.; Heller, M. [Klinik fuer Radiologische Diagnostik, Christian-Albrechts-Universitaet, Kiel (Germany)

1999-04-01

Anterior knee pain is a frequently encountered orthopedic symptom and is often associated with patellofemoral malalignment, which may cause chondromalacia of the patella. The difficulty in determining the patellar position between 0 and 30 of knee flexion with a conventional axial radiographic examination is well known. The introduction of computed tomography (CT) and magnetic resonance (MR) imaging for the diagnosis of knee joint abnormalities has enabled assessment of the patellar position in this critical range. More recently, emphasis has been placed on dynamic visualization of patellar motion to detect an abnormal tracking pattern. The important influence of the quadriceps muscle on the patellar tracking pattern is well known and has been examined during active knee extension by the use of ultrafast CT, and motion-triggered and ultrafast MR imaging. This article provides an overview of the current status of kinematic CT and MR imaging in the diagnosis of patellofemoral alignment, its clinical implications, and future directions. (orig.) With 13 figs., 5 tabs., 47 refs.

SPECT/CT for staging and treatment monitoring in oncology. Applications in differentiated thyroid cancer and liver tumors; SPECT/CT zum initialen Staging und Therapiemonitoring in der Onkologie. Indikationen beim differenzierten Schilddruesenkarzinom und bei Lebertumoren

Energy Technology Data Exchange (ETDEWEB)

Weber, K.; Berger, F.; Reiser, M.F. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Innenstadt, Institut fuer Klinische Radiologie, Muenchen (Germany); Mustafa, M.; Bartenstein, P.; Haug, A. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Klinik und Poliklinik fuer Nuklearmedizin, Muenchen (Germany)

2012-07-15

and SPECT/CT provides more accurate imaging of the arterial supply of the liver and of potential outflows of micro-spheres into other organs. SPECT/CT allows evaluation and quantification of the uptake of liver tumors. Improved postablative staging in patients with differentiated thyroid cancer by SPECT/CT in comparison to radioiodine whole body scans can be achieved. Improved planning and monitoring of SIRT therapies utilizing SPECT/CT leads to optimized therapeutic doses within liver lesions. Integration of SPECT/CT into the clinical standard for postablative staging in patients with DTC is recommended as well as utilization of SPECT/CT during the planning process, for dose calculation and treatment monitoring of SIRT therapies. (orig.) [German] In den letzten Jahren hat die Hybridbildgebung mit Verbindung von funktioneller und morphologischer Information zur Diagnostik zahlreicher Erkrankungen zunehmend an Bedeutung gewonnen. Bei Patienten mit differenziertem Schilddruesenkarzinom (DTC) wird nach erfolgter Radiojodtherapie (RJT) ein planares Ganzkoerperszintigramm zum Staging durchgefuehrt. Die diagnostische Genauigkeit dieser szintigraphischen Methode ist jedoch aufgrund limitierter raeumlicher Aufloesung begrenzt. Die Radioembolisation von mit {sup 90}Yttrium beladenen Mikrosphaeren (selektive interne Radiotherapie, SIRT) ermoeglicht eine wenig invasive Therapie primaerer und sekundaerer Lebertumoren. Zur Vermeidung von Nebenwirkungen der Mikrosphaeren durch einen Abstrom in Darm, Magen und Lunge muss vor Therapiebeginn eine Darstellung des durch die leberversorgenden Arterien versorgten Gebiets mittels {sup 99m}Tc-MAA ({sup 99m}Technetium-makroaggregiertes Albumin) und einer Szintigraphie erfolgen. Auch hier limitiert die begrenzte morphologische Information der Szintigraphie das Therapiemonitoring. {sup 131}Jod-Ganzkoerperszintigramm zum Nachweis einer erfolgreichen Ablation und Staging ca. 3-4 Tage postablativ bei Patienten mit DTC. Ueberwachung des

MR imaging of prostate cancer; MR-Tomographie des Prostatakarzinoms

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Heuck, A.; Scheidler, J.; Sommer, B.; Graser, A. [Radiologisches Zentrum Muenchen-Pasing (Germany); Mueller-Lisse, U.G. [Institut fuer Klinische Radiologie, Universitaet Muenchen (Germany); Massmann, J. [Gemeinschaftspraxis Pathologie, Muenchen (Germany)

2003-06-01

Accurate diagnosis and staging of prostate cancer (PC) is developing into an important health care issue in light of the high incidence of PC and the improvements in stage-adapted therapy. The purpose of this paper is to provide an overview on the current role of MR imaging and MR spectroscopy in the diagnosis and staging of PC.Material and methods Pertinent literature was searched and evaluated to collect information on current clinical indications, study techniques, diagnostic value, and limitations of magnetic resonance imaging and spectroscopy. Major indications for MR imaging of patients with supected PC are to define tumor location before biopsy when clinical or TRUS findings are inconclusive, and to provide accurate staging of histologically proven PC to ascertain effective therapy. Current MR imaging techniques for the evaluation of PC include multiplanar high-resolution T2-weighted FSE and T1-weighted SE sequences using combined endorectal and phased-array coils. Using these techniques, the reported accuracy of MR imaging for the diagnosis of extracapsular tumor extension ranges between 82 and 88% with sensitivities between 80 and 95%, and specificities between 82 and 93%. Typical MR findings of PC in different stages of disease, as well as diagnostic problems, such as chronic prostatitis, biopsy-related hemorrhage and therapy-related changes of prostatic tissue are discussed. In addition, the current perspectives and limitations of MR spectroscopy in PC are summarized. Current MR imaging techniques provide important diagnostic information in the pretherapeutic workup of PC including a high staging accuracy, and is superior to TRUS. (orig.) [German] Der Diagnostik des Prostatakarzinoms kommt wegen seiner hohen Inzidenz und den verbesserten stadienadaptierten Therapiemoeglichkeiten eine grosse Bedeutung zu. Dabei spielen bildgebende Verfahren bei den klinisch oft unzureichend diagnostizierbaren Faellen eine wesentliche Rolle fuer die praetherapeutische

Multimodality imaging with CT, MR and FDG-PET for radiotherapy target volume delineation in oropharyngeal squamous cell carcinoma

International Nuclear Information System (INIS)

Bird, David; Scarsbrook, Andrew F.; Sykes, Jonathan; Ramasamy, Satiavani; Subesinghe, Manil; Carey, Brendan; Wilson, Daniel J.; Roberts, Neil; McDermott, Gary; Karakaya, Ebru; Bayman, Evrim; Sen, Mehmet; Speight, Richard; Prestwich, Robin J.D.

2015-01-01

This study aimed to quantify the variation in oropharyngeal squamous cell carcinoma gross tumour volume (GTV) delineation between CT, MR and FDG PET-CT imaging. A prospective, single centre, pilot study was undertaken where 11 patients with locally advanced oropharyngeal cancers (2 tonsil, 9 base of tongue primaries) underwent pre-treatment, contrast enhanced, FDG PET-CT and MR imaging, all performed in a radiotherapy treatment mask. CT, MR and CT-MR GTVs were contoured by 5 clinicians (2 radiologists and 3 radiation oncologists). A semi-automated segmentation algorithm was used to contour PET GTVs. Volume and positional analyses were undertaken, accounting for inter-observer variation, using linear mixed effects models and contour comparison metrics respectively. Significant differences in mean GTV volume were found between CT (11.9 cm 3 ) and CT-MR (14.1 cm 3 ), p < 0.006, CT-MR and PET (9.5 cm 3 ), p < 0.0009, and MR (12.7 cm 3 ) and PET, p < 0.016. Substantial differences in GTV position were found between all modalities with the exception of CT-MR and MR GTVs. A mean of 64 %, 74 % and 77 % of the PET GTVs were included within the CT, MR and CT-MR GTVs respectively. A mean of 57 % of the MR GTVs were included within the CT GTV; conversely a mean of 63 % of the CT GTVs were included within the MR GTV. CT inter-observer variability was found to be significantly higher in terms of position and/or volume than both MR and CT-MR (p < 0.05). Significant differences in GTV volume were found between GTV volumes delineated by radiologists (9.7 cm 3 ) and oncologists (14.6 cm 3 ) for all modalities (p = 0.001). The use of different imaging modalities produced significantly different GTVs, with no single imaging technique encompassing all potential GTV regions. The use of MR reduced inter-observer variability. These data suggest delineation based on multimodality imaging has the potential to improve accuracy of GTV definition. ISRCTN Registry: ISRCTN34165059. Registered 2

CT and MR imaging of primary tumors of the masticator space

International Nuclear Information System (INIS)

Aspestrand, F.; Boysen, M.

1992-01-01

A retrospective study of CT and MR examinations in 14 patients with benign and malignant tumors originating in the masticator space is presented. At presentation, 12 patients revealed tumor extension to adjacent regions and spaces. Perineutral tumor spread along trigeminal nerve branches to the cavernous sinus and orbits was combined with facial pain, and/or numbness, ophthalmoplegia, and exophthalmus. Detailed analysis of tumor growth and spread, enhancement and signal features at CT and MR imaging indicated that tumor histology was, with a few exceptions, nonspecific. More extensive growth and bone destruction was noted only among malignant tumors. MR imaging was found superior to CT in delineating tumor extension due to better soft tissue contrast resolution and multiplanar imaging. Posttreatment examinations were available in 11 patients and showed long-standing regional edema of the adjacent temporal lobe and masticator muscles in 4 out of 5 patients without clinical evidence of tumor. In 6 patients, CT and MR features were found almost unchanged with only small size differences after various forms of treatment. (orig.)

CT and MR findings of the inverted papilloma

International Nuclear Information System (INIS)

Lim, Seong Youb; Kim, Hak Jin; Lee, Jun Woo; Park, Jae Yeong; Lee, Sung Gap; Kim, Byung Soo; Roh, Hwan Jung; Baik, Seung Kook

1997-01-01

The purpose of this study is to describe the CT and MR findings of inverted papilloma and to determine the specific differential finding between inverted papilloma with and without coexisting malignancy. Twenty-two histopathologically proven inverted papillomas were included in this study ; in six patients there was coexisting malignancy. Twenty-two CT images and eight MR images were retrospectively reviewed. On CT images, the inverted papillomas were seen as unilateral sinonasal masses with bone remodeling (n=15) rather than bone destruction (n=1) and showed iso- or slightly high attenuation. Three of the six malignant cases showed aggressive bone destruction and widespread extension into the orbit, intracranial and buccal spaces, and pterygopalatine fossa. On MR images, the inverted papillomas (n=3) were iso- (n=2) or slightly high (n=1) in signal intensity in relation to muscle on T1-weighted images, and high (n=3) on T2-weighted images. Gadolinium enhanced images showed heterogenous moderate enhancement. In the cases of coexisting malignancy (n=5), the masses were iso- (n=5) on T1-weighted images, high (n=5) on T2-weighted images and also showed heterogenous moderate enhancement. Inverted papilloma should be considered in the differential diagnosis of a bulky unilateral nasal mass extending into the adjacent paranasal sinuses, especially in an elderly patient with chronic nasal obstruction. Although there were no specific differential findings in signal intensity and enhancement pattern on CT and MR images between benign and malignant inverted papilloma, aggressive bone destruction and widespread extension beyond the sinonasal cavity are findings which are highly suggestive of coexisting malignancy

Technique of proton and phosphorous MR spectroscopy; Technik der Protonen- und Phosphor-MR-Spektroskopie

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Backens, M. [Universitaetsklinikum des Saarlandes, Klinik fuer Diagnostische und Interventionelle Neuroradiologie, Homburg/Saar (Germany)

2017-06-15

Magnetic resonance spectroscopy (MRS) is an important non-invasive method that can reveal the concentration and spatial distribution of particular biochemically relevant tissue metabolites. Proton MRS is routinely applicable in the clinical setting providing good quality results even with a moderate magnetic field strength of 1.5 T. Relative values of metabolite concentrations are mostly used for the assessment of metabolic disorders. Absolute quantification of metabolites can be achieved by means of internal or external reference scans. Phosphorous MRS extends the range of detectable molecules to energy and cell membrane metabolism. The lower detection limit of metabolite concentrations is in the range of some mmol/kg. Depending on the magnetic field strength, MRS enables a spatial resolution of a few milliliters. The use of phosphorous MRS is considerably limited because higher field strengths of at least 3.0 T and additional expensive hardware for signal processing are required. (orig.) [German] Die MR-Spektroskopie (MRS) ist eine wichtige nichtinvasive Untersuchungsmethode, die Konzentration und raeumliche Verteilung einiger biochemisch relevanter Metaboliten im Gewebe ermitteln kann. Die Protonenspektroskopie ist klinisch etabliert, in der Routine einfach durchfuehrbar und liefert bereits bei einer Magnetfeldstaerke von 1,5 T qualitativ gute Ergebnisse. Fuer die Beurteilung von Stoffwechselveraenderungen werden Metabolitenkonzentrationen meist als Relativwerte angegeben. Mithilfe interner oder externer Referenzmessungen sind auch absolute Metabolitenkonzentrationen berechenbar. Die Phosphorspektroskopie erweitert den Bereich der detektierbaren Molekuele auf den Energie- und Zellmembranstoffwechsel. Die minimale nachweisbare Metabolitenkonzentration liegt bei einigen mmol/kg. Abhaengig von der Magnetfeldstaerke ist eine raeumliche Aufloesung der MRS von wenigen Millilitern erreichbar. Der Einsatz der Phosphor-MRS wird dadurch erheblich eingeschraenkt, dass sie

Studies on image quality, high contrast resolution and dose for the axial skeleton and limbs with a new, dedicated CT system (ISO-C-3D); Untersuchungen zur Bildqualitaet, Hochkontrastaufloesung und Dosis am Stamm- und Gliedmassenskelett mit einem neuen dedizierten CT-System (ISO-C-3D)

Energy Technology Data Exchange (ETDEWEB)

Rock, C.; Kotsianos, D.; Linsenmaier, U. [Klinikum der Universitaet Muenchen, Muenchen (Germany). Inst. fuer Klinische Radiologie; Fischer, T. [Klinikum der Universitaet Muenchen, Muenchen (DE). Inst. fuer Klinische Radiologie] (and others)

2002-02-01

Purpose: Evaluation of 3D-CT imaging of the axial skeleton and different joints of the lower and upper extremities with a new dedicated CT system (ISO-C-3D) based on a mobile isocentric C-arm image amplifier. Material and Methods: 27 cadaveric specimes of different joints of the lower and upper extremities and of the spinal column were examined with 3D-CT imaging (ISO-C-3d). All images were evaluated by 3 radiologists for image quality using a semiquantitative score (score value 1: poor quality; score value 4: excellent quality). In addition, dose measurements and measurements of high contrast resolution were performed in comparison to conventional and low-dose spiral CT using a high contrast phantom (Catphan, Phantom Laboratories). Results: Adequate image quality (mean score values 3-4) could be achieved with an applied dose comparable to low-dose CT in smaller joints such as wrist, elbow, ankle and knee. A remarkably inferior image quality resulted in imaging of the hip, lumbar and thoracic spine (mean score values 2-3) in spite of almost doubling the dose (dose increased by 85 percent). The image quality of shoulder examinations was insufficient (mean score value 1). Phantom studies showed a high-contrast resolution comparable to helical CT in the xy-axis (9 lp/cm). Conclusion: Preliminary results show, that image quality of C-arm-based CT-imaging (ISO-C-3D) seems to be adequate in smaller joints. ISO-C-3D images of the hip and axial skeleton show a decreased image quality, which does not seem to be sufficient for diagnosing subtle fractures. (orig.) [German] Zielsetzung: Evaluierung der 3D-CT-Bildgebung mit einem C-Bogen-basierten dedizierten CT-System (ISO-C-3D, Fa. Siemens) an Extremitaetengelenken und am Stammskelett. Methodik: 27 humane Leichenpraeparate der unteren und oberen Extremitaet sowie des Stammskeletts wurden am ISO-C-3D untersucht und die Bilddaten anhand eines Bildqualitaetsscores von 3 Untersuchern semiquantitativ evaluiert (Score 1: nicht

Indications for CT and MR arthrography. Recommendations of the Musculoskeletal Workgroup of the DRG; Indikationen der MR- und CT-Arthrografie. Empfehlungen der AG Muskuloskelettale Radiologie der DRG

Energy Technology Data Exchange (ETDEWEB)

Fischer, W. [Hessingpark Clinic, Radiologengemeinschaft Augsburg (Germany); Bohndorf, K.; Zentner, J. [Zentralklinikum Augsburg (Germany). Klinik fuer Diagnostische Radiologie und Neuroradiologie; Kreitner, K.F. [Universitaetsklinikum Mainz (Germany). Klinik und Poliklinik fuer Radiologie; Schmitt, R. [Herz- und Gefaessklinik GmbH, Bad Neustadt an der Saale (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Woertler, K. [Klinikum rechts der Isar, Muenchen (Germany). Inst. fuer Roentgendiagnostik

2009-05-15

The ongoing discussion about CT and MR arthrography is at least in part due to the lack of definite guidelines. The intention of the musculoskeletal workgroup of the DRG (Deutsche Roentgengesellschaft) was the establishment of recommendations for general guidance. After review of the recent literature, the indications for arthrographic examinations were discussed during a consensus meeting. Since the published data are insufficient and partially contradictory, no precise statements could be extracted from the literature. Therefore, the proposed recommendations are mainly based on expert opinions. In this review the main statements of the published literature are summarized and the recommendations of the musculoskeletal workgroup of the DRG are presented. (orig.)

CT and MR imaging of the knee joint in the ''plica syndrome''

International Nuclear Information System (INIS)

Passariello, R.; Trecco, F.; De Paulis, F.; Masciocchi, C.; Zobel, B.B.; Buoni, C.

1986-01-01

''Synovial plicae'' are present in 60% of adult knees and can be the cause of a nonspecific clinical picture known as the plica syndrome. Direct high-resolution CT and MR imaging were performed on 30 patients with serious clinical signs of plica syndrome. All patients underwent anthroscopy. Twelve infrapetallar, eight suprapatellar, and 22 medical synovial plicae were shown (in 12 cases two different plicae were present). In seven cases there were other associated lesions: one case of patellar tendinitis, three medial meniscus lesions, one lateral diskoid meniscus, and two patellar subluxations. The diagnostic accuracy of both CT and MR imaging were compared with arthroscopy. CT always showed the plicae and defined their types, locations, and associations with other lesions. MR imaging was superior to CT in characterizing the morphology of the plica (related with symptomatology) and in showing the femoral and patellar chondromalacia secondary to the plica itself. MR imaging was equally accurate in revealing the tendinitis and the patellar subluxations, but CT was superior in displaying the meniscal lesions and the diskoid meniscus

Generating patient specific pseudo-CT of the head from MR using atlas-based regression

International Nuclear Information System (INIS)

Sjölund, J; Forsberg, D; Andersson, M; Knutsson, H

2015-01-01

Radiotherapy planning and attenuation correction of PET images require simulation of radiation transport. The necessary physical properties are typically derived from computed tomography (CT) images, but in some cases, including stereotactic neurosurgery and combined PET/MR imaging, only magnetic resonance (MR) images are available. With these applications in mind, we describe how a realistic, patient-specific, pseudo-CT of the head can be derived from anatomical MR images. We refer to the method as atlas-based regression, because of its similarity to atlas-based segmentation. Given a target MR and an atlas database comprising MR and CT pairs, atlas-based regression works by registering each atlas MR to the target MR, applying the resulting displacement fields to the corresponding atlas CTs and, finally, fusing the deformed atlas CTs into a single pseudo-CT. We use a deformable registration algorithm known as the Morphon and augment it with a certainty mask that allows a tailoring of the influence certain regions are allowed to have on the registration. Moreover, we propose a novel method of fusion, wherein the collection of deformed CTs is iteratively registered to their joint mean and find that the resulting mean CT becomes more similar to the target CT. However, the voxelwise median provided even better results; at least as good as earlier work that required special MR imaging techniques. This makes atlas-based regression a good candidate for clinical use. (paper)

Von Mr Classic zu Mr Nerd: Wie Forschende soziale Medien nutzen

Directory of Open Access Journals (Sweden)

Doreen Siegfried

2014-12-01

Full Text Available Unter Wissenschaftlerinnen und Wissenschaftlern lassen sich vier Typen differenzieren, die ein signifikant unterschiedliches Verhalten in ihrer Nutzung und ihrer Einstellung gegenüber Social-Web-Anwendungen zeigen: Ms Maker, Mr Tech, Mr Classic und Mr Nerd. Grundlage für die Identifizierung dieser Social-Media-Typen ist die Auswertung von 778 Online-Fragebögen, die von Anfang September bis Mitte Oktober 2013 erhoben wurden. Erfragt wurde die Nutzung von Social-Media-Instrumenten für die tägliche Arbeit in Forschung, Lehre, Administration und Wissenschaftskommunikation. Neben Intensität und Kontext der Nutzung von Web-2.0-Diensten wurden auch die Gründe für Nutzung bzw. Nicht-Nutzung einzelner Kanäle sowie generelle Einstellungen gegenüber Social-Media-Werkzeugen erfragt. Among scientists, four types of personality can be identified whose usage and attitude towards social web applications show significant variations: Ms Maker, Mr Tech, Mr Classic and Mr Nerd. This typification is based on 778 online questionnaires received between September and October 2013. The survey sampled the usage of social media tools for daily routines in research, teaching, administrative work and scholarly communication. The survey asked questions about the intensity and the context in which Web 2.0 services are used, about the reasons for (not using certain channels, and about general attitudes towards social media tools.

Evaluation of injuries of the upper cervical spine in a postmortem study with digital radiography, CT and MRI; Evaluation experimentell erzeugter Verletzungen der oberen Halswirbelsaeule mit digitaler Roentgentechnik, Computertomographie und Magnetresonanztomographie

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Obenauer, S.; Herold, T.; Fischer, U.; Grabbe, E. [Goettingen Univ. (Germany). Abt. fuer Roentgendiagnostik; Fadjasch, G.; Saternus, K.S. [Goettingen Univ. (Germany). Abt. fuer Rechtsmedizin; Koebke, J. [Koeln Univ. (Germany). Anatomisches Inst.

1999-12-01

Purpose: To compare digital X-ray, CT, and MRI in the evaluation of ligamentous and osseous lesions in upper cervical spine specimens after artificial craniocervical injury with the findings of macroscopic preparation. Materials and Methods: A rotation trauma of defined severity was applied to 19 human corpses. After dissection of the neck specimens, digital X-ray (DIMA Soft P41, Feinfocus), conventional and helical CT (CTi, High Speed, GE, collimation 1 mm; pitch 1.0), and MRI were performed from the skull base to C3. The findings were correlated with the macroscopic results of preparation. MR (Magnetom Vision, Siemens) imaging was obtained with a 1.5 T system using 2D- and 3D-sequences. Results: Preparation revealed 6 fractures of the vertebral bodies, 5 fractures of the dens axis, 1 fracture of the arcus anterior of the atlas, 4 osseous flakes at the occipital condylus, and 6 lesions of the alar ligaments. Digital radiography showed all fractures and 4 osseous flakes at the occipital condylus. With conventional and helical CT, all fractures and all ruptured alar ligaments could be detected. 2D MRI depicted 9 of the fractures and 3D MRI showed fractures. With 2D MRI, 2 of the 4 osseous flakes at the condylus could be detected and with 3D MRI one occipital condylus fracture could be depicted. Ligamentous injuries were visualized by 2D MRI in 2 of 6 cases and by 3 D MRI inone case. Conclusions: In post-mortem studies, CT was superior to MRI in the visualization of osseous and ligamentous injuries after trauma of the upper cervical spine. However, these results are not transferable to patients with rotation injury in general. (orig.) [German] Ziel: Vergleich verschiedener Techniken (digitale Roentgentechnik, Computertomographie, Magnetresonanztomographie) in der Detektion von ligamentaeren und ossaeren Laesionen der oberen Halswirbelsaeule nach definiertem Trauma sowie Korrelation mit den experimentellen Praeparateergebnissen. Material und Methoden: 19 menschliche

Cartilage lesions in the ankle joint: comparison of MR arthrography and CT arthrography

International Nuclear Information System (INIS)

Schmid, M.R.; Pfirrmann, C.W.A.; Hodler, J.; Zanetti, M.; Vienne, P.

2003-01-01

To compare MR arthrography and CT arthrography for the evaluation of cartilage lesions in the ankle joint.Design and patients Thirty-six consecutive patients with clinically suspected cartilage lesions were prospectively included in the study. A 1:1 mixture of diluted gadoteridol (4 mmol/l) and iopamidol (300 mg iodine/ml) was injected. The articular cartilages of the talus, tibia, and fibula were analyzed separately by two musculoskeletal radiologists. A review panel consisting of two musculoskeletal radiologists and an orthopedic surgeon represented the standard of reference. For reader 1 accuracy of MR arthrography in the talus/tibia/fibula (88%/88%/94%) was slightly inferior to CT arthrography (90%/94%/92%). For reader 2, the accuracy was 76%/78%/83% for MR arthrography, and 92%/93%/92% for CT arthrography, respectively. Interobserver agreement for MR arthrography was 79%/74%/89% (kappa 0.47/0.34/0.27), while interobserver agreement for CT arthrography was 89%/90%/89% (kappa 0.69/0.54/0.54). CT arthrography appears to be more reliable than MR arthrography for the detection of cartilage lesions in the ankle joint. (orig.)

MR of the muskuloskeletal system: A review; MR-Tomographie (MRT) des Skeletts, der peripheren Weichteile und der Gelenke - aktuelle Uebersicht

Energy Technology Data Exchange (ETDEWEB)

Bohndorf, K. [Zentralklinikum Augsburg (Germany). Klinik fuer Diagnostische und Neuroradiologie; Kretschmer, K.H. [Zentralklinikum Augsburg (Germany). Klinik fuer Diagnostische und Neuroradiologie

1996-05-01

The skeleton, the peripheral soft tissues, and the joints have become important indications to use MRI routinely. About 25-35% of daily examinations focus on these anatomic sites. Superior contrast resolution, the option of different imaging planes, and the unsurpassed visualization of bone marrow, fibrous and hyaline cartilage, ligaments, and tendons are the reasons for the overwhelming success of this imaging method. MRI often provides the direct way to diagnosis. More and more the so-called `step by step` approach to diagnosis by imaging methods is being abandoned in favor of the primary use of MRI. The present survey summarizes the main indications for MRI in the field of the musculoskeletal system, in adults as well as in children. Special topics like tumors, inflammation, ischemia, and trauma are discussed. Some anatomic sites like the carpal joint, the shoulder, and the knee are presented in more detail. (orig.) [Deutsch] Eine Vielzahl von Fragestellungen zu wesentlichen Indikationen der MR-Tomographie am Skelett, den peripheren Weichteilen und den Gelenken haben sich in der taeglichen Praxis entwickelt. Durchschnittlich 25-35% der taeglichen Untersuchungen betreffen diesen Themenkreis. Ueberlegene Kontrastaufloesung, die Darstellung in beliebig waehlbaren Ebenen und die unuebertroffene Visualisierung von Strukturen wie Knochenmark, fibroesem und hyalinem Knorpel, Ligamenten und Sehnen, sind die Ursache der raschen Verbreitung der Methode. Die MRT stellt haeufig den direkten Weg zur Diagnose dar und ersetzt zunehmend die sog. `Stufendiagnostik` und damit Methoden wie die Computertomographie, Arteriographie oder auch Skelettszintigraphie. In der vorliegenden Uebersicht werden wesentliche, heute als gesichert anzusehenden Anwendungsgebiete der MRT bei Kindern und Erwachsenen zusammengefasst. Die Arbeit gibt einen Ueberblick ueber spezielle Fragestellungen bei Tumoren, Entzuendungen, Ischaemie und traumatischen Fragestellungen. Eine Reihe von anatomischen

MR-based synthetic CT generation using a deep convolutional neural network method.

Science.gov (United States)

Han, Xiao

2017-04-01

Interests have been rapidly growing in the field of radiotherapy to replace CT with magnetic resonance imaging (MRI), due to superior soft tissue contrast offered by MRI and the desire to reduce unnecessary radiation dose. MR-only radiotherapy also simplifies clinical workflow and avoids uncertainties in aligning MR with CT. Methods, however, are needed to derive CT-equivalent representations, often known as synthetic CT (sCT), from patient MR images for dose calculation and DRR-based patient positioning. Synthetic CT estimation is also important for PET attenuation correction in hybrid PET-MR systems. We propose in this work a novel deep convolutional neural network (DCNN) method for sCT generation and evaluate its performance on a set of brain tumor patient images. The proposed method builds upon recent developments of deep learning and convolutional neural networks in the computer vision literature. The proposed DCNN model has 27 convolutional layers interleaved with pooling and unpooling layers and 35 million free parameters, which can be trained to learn a direct end-to-end mapping from MR images to their corresponding CTs. Training such a large model on our limited data is made possible through the principle of transfer learning and by initializing model weights from a pretrained model. Eighteen brain tumor patients with both CT and T1-weighted MR images are used as experimental data and a sixfold cross-validation study is performed. Each sCT generated is compared against the real CT image of the same patient on a voxel-by-voxel basis. Comparison is also made with respect to an atlas-based approach that involves deformable atlas registration and patch-based atlas fusion. The proposed DCNN method produced a mean absolute error (MAE) below 85 HU for 13 of the 18 test subjects. The overall average MAE was 84.8 ± 17.3 HU for all subjects, which was found to be significantly better than the average MAE of 94.5 ± 17.8 HU for the atlas-based method. The DCNN

Comparison of CT and MR in 400 patients with suspected disease of the brain and cervical spinal cord

Energy Technology Data Exchange (ETDEWEB)

Bradley, W.G. Jr.; Waluch, V.; Yadley, R.A.; Wycoff, R.R.

1984-09-01

Magnetic resonance imaging (MR) (0.35T) and computed tomography (CT) were compared in 400 consecutive patients with suspected disease of the brain and cervical spinal cord. Of 325 positive diagnoses, MR detected abnormality while CT was normal in 93; MR was more specific in 68; MR and CT gave equivalent information in 129; CT was more specific in 32; and CT was positive while MR was normal in 3. MR was superior to CT in detection of multiple sclerosis, subcortical arteriosclerotic encephalopathy, posterior fossa infarcts and tumors, small extra-axial fluid collections, and cervical syringomyelia. CT was preferable in evaluation of meningiomas and separation of tumor from edema. CT takes less time and may be preferable in patients with acute trauma as well as very young or elderly individuals. Thus the two studies should be considered complementary.

Comparison of CT and MR in 400 patients with suspected disease of the brain and cervical spinal cord

International Nuclear Information System (INIS)

Bradley, W.G. Jr.; Waluch, V.; Yadley, R.A.; Wycoff, R.R.

1984-01-01

Magnetic resonance imaging (MR) (0.35T) and computed tomography (CT) were compared in 400 consecutive patients with suspected disease of the brain and cervical spinal cord. Of 325 positive diagnoses, MR detected abnormality while CT was normal in 93; MR was more specific in 68; MR and CT gave equivalent information in 129; CT was more specific in 32; and CT was positive while MR was normal in 3. MR was superior to CT in detection of multiple sclerosis, subcortical arteriosclerotic encephalopathy, posterior fossa infarcts and tumors, small extra-axial fluid collections, and cervical syringomyelia. CT was preferable in evaluation of meningiomas and separation of tumor from edema. CT takes less time and may be preferable in patients with acute trauma as well as very young or elderly individuals. Thus the two studies should be considered complementary

The usefulness of CT and MR imaging in the preoperative evaluation of neoplasms of the craniofacial region

International Nuclear Information System (INIS)

Grzesiakowska, U.; Tacikowska, M.; Krajewski, R.; Starosciak, S.; Smorczewska, M.; Wiszniewska-Rawlik, D.

2005-01-01

The aim of the study was to determine the usefulness of CT and MR imaging in the preoperative evaluation of neoplasms of the craniofacial region. All the patients were treated surgically. CT and/or MR imaging was done in every patient for preoperative evaluation of soft tissue infiltration, destruction of bone structures, and metastasis of lymph nodes of the head and neck. The results of these imagings were compared with surgical evaluations and microscopic examination of postoperative specimens. Both CT and MR imaging have high accuracy in evaluating soft tissue infiltration. CT imaging is much better than MR in evaluating bony destruction. MR imaging is better in evaluating recurrent tumors, in which CT has very low specificity. MR imaging is the only method for evaluating infiltration of the central nervous system.The authors propose the following diagnostic algorithm: CT imaging for initial evaluation before treatment, MR imaging in suspected cases of infiltration of the central nervous system, and MR imaging in recurrent tumors after surgical and radiation treatment. (author)

The CT and MR evaluation of migrational disorders of the brain. Pt. 2

International Nuclear Information System (INIS)

Byrd, S.E.; Osborn, R.E.; Bohan, T.P.; Naidich, T.P.

1989-01-01

The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria - pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (Part II) deals with our patients with schizencephaly, heterotopia and polymicrogyria. These patients presented clinically with a variety of symptoms. The most common were seizures, delayed development, failure to thrive and hydrocephalus. CT and MR both demonstrated the characteristic findings in all of our patients except the polymicrogyria group. The gray matter and cleft abnormalities seen in these disorders were demonstrated with CT and MR. However, MR provided better delineation of these disorders than CT. Because some forms of migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling. (orig.)

CT and MR imaging of rhinocerebral mucormycosis

International Nuclear Information System (INIS)

Press, G.A.; Weindling, S.M.; Hesselink, J.R.

1987-01-01

Eight patients with biopsy-proven rhinocerebral mucormycosis had postcontrast CT. MR examination (1.5T) was also performed in two patients. Unilateral maxillary and ethmoid sinus disease with orbital apex extension was seen in five of six patients examined preoperatively. T2-weighted images showed intracranial extension as hyperintensity and mass effect in gray matter and white matter of frontal and temporal lobes, hypothalamus, thalamus, and pons in two patients. In the region of septic thrombosis of the cavernous sinus and internal carotid artery, MR detected inflammatory tissue of mixed signal intensity replacing the expected carotid signal void and petrous apex. Resolution of MR findings correlated with clinical improvement in one surviving patient

SU-F-I-51: CT/MR Image Deformation: The Clinical Assessment QA in Target Delineation

Energy Technology Data Exchange (ETDEWEB)

Yang, C; Chen, Y [Monmouth Medical Center, Long Branch, NJ (United States)

2016-06-15

Purpose: To study the deformation effects in CT/MR image registration of head and neck (HN) cancers. We present a clinical indication in guiding and simplifying registration procedures of this process while CT images possessed artifacts. Methods: CT/MR image fusion provides better soft tissue contrast in intracranial GTV definition with artifacts. However, whether the fusion process should include the deformation process is questionable and not recommended. We performed CT/MR image registration of a HN patient with tonsil GTV and nodes delineation on Varian Velocity™ system. Both rigid transformation and deformable registration of the same CT/MR imaging data were processed separately. Physician’s selection of target delineation was implemented to identify the variations. Transformation matrix was shown with visual identification, as well as the deformation QA numbers and figures were assessed. Results: The deformable CT/MR images were traced with the calculated matrix, both translation and rotational parameters were summarized. In deformable quality QA, the calculated Jacobian matrix was analyzed, which the min/mean/max of 0.73/0/99/1.37, respectively. Jacobian matrix of right neck node was 0.84/1.13/1.41, which present dis-similarity of the nodal area. If Jacobian = 1, the deformation is at the optimum situation. In this case, the deformation results have shown better target delineation for CT/MR deformation than rigid transformation. Though the root-mean-square vector difference is 1.48 mm, with similar rotational components, the cord and vertebrae position were aligned much better in the deformable MR images than the rigid transformation. Conclusion: CT/MR with/without image deformation presents similar image registration matrix; there were significant differentiate the anatomical structures in the region of interest by deformable process. Though vendor suggested only rigid transformation between CT/MR assuming the geometry remain similar, our findings

CT and MR findings of ovarian fibroma

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Kong, Soo Jin; Rho, Myung Ho; Kim, Byung Heon; Song, Yun Gyu; Lee, Soo Han; Choi, Pil Yeob; Sung, Young Soon; Kwon, Jae Soo; Lee, Sang Wook [Masan Samsung Hospital, Masan (Korea, Republic of)

1997-08-01

To evaluate the charateristic CT and MR findings of the primary ovarian fibromas. We retrospectively reviewed 11 cases which had undergone precontrast and postcontrast scanning, and two in which cases T1-weighted (WI) and postcontrast T1WI and T2WI images had been done. All cases were pathologically confirmed after surgical resection. These masses were analysed on the bases of clinical symptoms, age, size(longest diameter), laterality, margin, attenuation(unenhanced and enhanced), signal intensity(SI), calcification, and amount of the ascites. The patients' mean age was 46.6(range, 22-81)years, and the longest diameter was 14.8(range, 8-28)cm. All tumors were unilateral, and eight were located in the left ovary and five in the right ovary. In all cases, the tumor margin was well-defined;seven were lobulated, four were oval, one was round, and one was nodularly marginated. On CT scan, the masses showed mild to moderate heterogenous enhancement with irregular lower density portions. The amount of the ascites was marked in three cases(23%), mild in two(15%), and minimal in three cases. Calcification were seen in 3 of 11 CT cases(27%), and in one, this was extensive. On MR scans, signal intensity (SI) of the masses on T1WI was isoSI, relativetive to the uterine myometrium, and heterogeneously enhanced after infusion of contrast media. On T2WI, SI was slightly lower that of the uterine myometrium with internal high SI portions. The characteristic finding of ovarian fibroma is a unilateral, well-defined, oval or lobulated, solid mass with or without ascites and calcification. On CT scan, tumor has mild to moderate heterogeneous enhancement. On MR scan, SI of mass is isoSI on T1WI with heterogeneous enhancement, and low SI on T2WI due to fibrous component.

Hybrid FDG-PET/MR compared to FDG-PET/CT in adult lymphoma patients.

Science.gov (United States)

Atkinson, Wendy; Catana, Ciprian; Abramson, Jeremy S; Arabasz, Grae; McDermott, Shanaugh; Catalano, Onofrio; Muse, Victorine; Blake, Michael A; Barnes, Jeffrey; Shelly, Martin; Hochberg, Ephraim; Rosen, Bruce R; Guimaraes, Alexander R

2016-07-01

The goal of this study is to evaluate the diagnostic performance of simultaneous FDG-PET/MR including diffusion compared to FDG-PET/CT in patients with lymphoma. Eighteen patients with a confirmed diagnosis of non-Hodgkin's (NHL) or Hodgkin's lymphoma (HL) underwent an IRB-approved, single-injection/dual-imaging protocol consisting of a clinical FDG-PET/CT and subsequent FDG-PET/MR scan. PET images from both modalities were reconstructed iteratively. Attenuation correction was performed using low-dose CT data for PET/CT and Dixon-MR sequences for PET/MR. Diffusion-weighted imaging was performed. SUVmax was measured and compared between modalities and the apparent diffusion coefficient (ADC) using ROI analysis by an experienced radiologist using OsiriX. Strength of correlation between variables was measured using the Pearson correlation coefficient (r p). Of the 18 patients included in this study, 5 had HL and 13 had NHL. The median age was 51 ± 14.8 years. Sixty-five FDG-avid lesions were identified. All FDG-avid lesions were visible with comparable contrast, and therefore initial and follow-up staging was identical between both examinations. SUVmax from FDG-PET/MR [(mean ± sem) (21.3 ± 2.07)] vs. FDG-PET/CT (mean 23.2 ± 2.8) demonstrated a strongly positive correlation [r s = 0.95 (0.94, 0.99); p < 0.0001]. There was no correlation found between ADCmin and SUVmax from FDG-PET/MR [r = 0.17(-0.07, 0.66); p = 0.09]. FDG-PET/MR offers an equivalent whole-body staging examination as compared with PET/CT with an improved radiation safety profile in lymphoma patients. Correlation of ADC to SUVmax was weak, understating their lack of equivalence, but not undermining their potential synergy and differing importance.

Discrimination and anatomical mapping of PET-positive lesions: comparison of CT attenuation-corrected PET images with coregistered MR and CT images in the abdomen

Energy Technology Data Exchange (ETDEWEB)

Kuhn, Felix P.; Crook, David W.; Mader, Caecilia E.; Appenzeller, Philippe; Schulthess, G.K. von; Schmid, Daniel T. [University Hospital Zurich, Department of Medical Radiology, Zurich (Switzerland)

2013-01-15

PET/MR has the potential to become a powerful tool in clinical oncological imaging. The purpose of this prospective study was to evaluate the performance of a single T1-weighted (T1w) fat-suppressed unenhanced MR pulse sequence of the abdomen in comparison with unenhanced low-dose CT images to characterize PET-positive lesions. A total of 100 oncological patients underwent sequential whole-body {sup 18}F-FDG PET with CT-based attenuation correction (AC), 40 mAs low-dose CT and two-point Dixon-based T1w 3D MRI of the abdomen in a trimodality PET/CT-MR system. PET-positive lesions were assessed by CT and MRI with regard to their anatomical location, conspicuity and additional relevant information for characterization. From among 66 patients with at least one PET-positive lesion, 147 lesions were evaluated. No significant difference between MRI and CT was found regarding anatomical lesion localization. The MR pulse sequence used performed significantly better than CT regarding conspicuity of liver lesions (p < 0.001, Wilcoxon signed ranks test), whereas no difference was noted for extrahepatic lesions. For overall lesion characterization, MRI was considered superior to CT in 40 % of lesions, equal to CT in 49 %, and inferior to CT in 11 %. Fast Dixon-based T1w MRI outperformed low-dose CT in terms of conspicuity and characterization of PET-positive liver lesions and performed similarly in extrahepatic tumour manifestations. Hence, under the assumption that the technical issue of MR AC for whole-body PET examinations is solved, in abdominal PET/MR imaging the replacement of low-dose CT by a single Dixon-based MR pulse sequence for anatomical lesion correlation appears to be valid and robust. (orig.)

Discrimination and anatomical mapping of PET-positive lesions: comparison of CT attenuation-corrected PET images with coregistered MR and CT images in the abdomen

International Nuclear Information System (INIS)

Kuhn, Felix P.; Crook, David W.; Mader, Caecilia E.; Appenzeller, Philippe; Schulthess, G.K. von; Schmid, Daniel T.

2013-01-01

PET/MR has the potential to become a powerful tool in clinical oncological imaging. The purpose of this prospective study was to evaluate the performance of a single T1-weighted (T1w) fat-suppressed unenhanced MR pulse sequence of the abdomen in comparison with unenhanced low-dose CT images to characterize PET-positive lesions. A total of 100 oncological patients underwent sequential whole-body 18 F-FDG PET with CT-based attenuation correction (AC), 40 mAs low-dose CT and two-point Dixon-based T1w 3D MRI of the abdomen in a trimodality PET/CT-MR system. PET-positive lesions were assessed by CT and MRI with regard to their anatomical location, conspicuity and additional relevant information for characterization. From among 66 patients with at least one PET-positive lesion, 147 lesions were evaluated. No significant difference between MRI and CT was found regarding anatomical lesion localization. The MR pulse sequence used performed significantly better than CT regarding conspicuity of liver lesions (p < 0.001, Wilcoxon signed ranks test), whereas no difference was noted for extrahepatic lesions. For overall lesion characterization, MRI was considered superior to CT in 40 % of lesions, equal to CT in 49 %, and inferior to CT in 11 %. Fast Dixon-based T1w MRI outperformed low-dose CT in terms of conspicuity and characterization of PET-positive liver lesions and performed similarly in extrahepatic tumour manifestations. Hence, under the assumption that the technical issue of MR AC for whole-body PET examinations is solved, in abdominal PET/MR imaging the replacement of low-dose CT by a single Dixon-based MR pulse sequence for anatomical lesion correlation appears to be valid and robust. (orig.)

A study on CT attenuation and MR signal intensity of protein solution

International Nuclear Information System (INIS)

Kim, Joung Hae; Choi, Dae Seob; Kim, Soon; Lee, Hyeon Kyeong; Oh, Hyeon Hee; Kim, Seung Hyeon; Lee, Sung Woo; Chang, Kee Hyun; Chung, Jun Ho

2001-01-01

To correlate CT attenuation and MR signal intensity with concentration of protein solution. CT and MR examinations of a phantom containing bovine serum albumin solutions of various concentrations ranging from 0 to 55% were performed. CT Hounsfield units(HUs), MR signal intensities, and apparent diffusion coefficients (ADCs) of each albumin solution were measured, and CT HUs and MR signal intensities of the solutions were compared with those of cerebrospinal fluid (CSF), white matter, and cortical gray matter. CT HU increased gradually with increasing albumin concentration. On T1-weighted images(T1WI), signal intensity increased with increasing albumin concentrations of up to 35% but then decreased. On T2-weighted images(T2Wl), gradually decreasing signal intensity and increasing albumin concentration were observed Fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted images (DWls) showed that signal intensity peaked at a concentration of 10% and then gradually decreased. The ADC of the solution gradually decreased as concentration increased. Compared with those of normal brain structures, the CT HUs of solutions at concentrations of over 20% were higher than those of white and gray matter. At T1WI, the signal intensities of 10-45% solutions were similar to or higher than that of the gray matter. At T2Wl, the signal intensities of solutions above 25, 35, and 40% were lower than those of CSF, gray matter, and white matter, respectively. FLAIR images showed that the signal intensities of 5-35% solutions were higher than that of gray matter. The CT attenuation of albumin solution increased gradually with increasing concentration. MR signal intensities peaked at 35% concentration on T1WI and at 10% on FLAIR and DW images, respectively, and then gradually decreased. T2Wl and ADC map images showed gradually decreasing signal intensity and ADC as albumin concentration increased

CT and MR imaging findings of sphenoidal masses

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Shoki; Higano, Shuichi (Tohoku Univ., Sendai (Japan). School of Medicine); Ishii, Kiyoshi (and others)

1994-07-01

CT and MR imaging findings of 57 sphenoidal masses were retrospectively reviewed to assess the possibility of differential diagnosis between them. Various kinds of masses such as pituitary adenoma, epipharyngeal cancer, mucocele, chordoma, chondroma, chondrosarcoma, distant metastasis, multiple myeloma, fibrous dysplasia, craniopharyngioma, hemangiopericytoma, giant cell tumor, primary sphenoidal cancer, malignant melanoma, leukemia, histiocytosis X, and giant cell tumor were included in this series. CT scanning was performed in all cases using a spin-echo pulse sequence. The relative density of the masses, bony changes and calcification were evaluated on CT, and on MR images, signal intensity of the masses relative to the normal gray matter, contrast enhancement and extension/contour were evaluated. Although no single feature appeared to be specific to the masses, detection of calcification on CT, identification of the normal pituitary gland as deformed or displaced on T1-weighted images, signal intensity on T2-weighted images, and extension of the masses seemed to be useful and should be examined in terms of their ability to assist in differential diagnosis. Finally, accommodative classification of sphenoidal masses primarily based on presumed origin or mode of extension was attempted. (author).

Detection and preoperative staging of carcinoma of the cervix: Comparison between MR imaging and CT

International Nuclear Information System (INIS)

Mayr, B.; Schmidt, H.; Baieri, P.; Scheidel, P.; Meier, W.; Schramm, T.

1986-01-01

Twenty-four patients with carcinoma of the cervix were examined preoperatively by MR imaging and CT. In all patients histopathologic confirmation was available for specimens obtained either by radical hysterectomy or at staging laparotomy. MR imaging was equivalent to contrast CT in the detection and evaluation of tumor extension in the cervix. Tumor extension to the parametria and pelvic wall was difficult to evaluate on both modalities, as neither had a higher accuracy than pelvic examination conducted under anesthesia. Nodal staging was nearly equivalent on MR imaging and CT. In the detection and staging of carcinoma of the cervix, MR imaged proved to be as good as CT with contrast agent enhancement

MR and CT imaging patterns in post-varicella encephalitis

Energy Technology Data Exchange (ETDEWEB)

Darling, C.F. [Div. of Neuroimaging, Children`s Memorial Center, Northwestern Univ. Medical School, Chicago, IL (United States); Larsen, M.B. [Div. of Neurology, Children`s Memorial Center, Northwestern Univ. Medical School, Chicago, IL (United States); Byrd, S.E. [Div. of Neuroimaging, Children`s Memorial Center, Northwestern Univ. Medical School, Chicago, IL (United States); Radkowski, M.A. [Div. of Neuroimaging, Children`s Memorial Center, Northwestern Univ. Medical School, Chicago, IL (United States); Palka, P.S. [Div. of Neuroimaging, Children`s Memorial Center, Northwestern Univ. Medical School, Chicago, IL (United States); Allen, E.D. [Div. of Neuroimaging, Children`s Memorial Center, Northwestern Univ. Medical School, Chicago, IL (United States)

1995-06-01

The aim of the investigation was to determine the patterns of cerebral involvement on computed tomography (CT) and magnetic resonance (MR) imaging in post-varicella encephalitis. Four children between the ages of 2 and 11 years presented over a 5-year period with a diagnosis of post-varicella encephalitis. Their imaging studies and clinical data were reviewed retrospectively. The medical histories of all four children were noncontributory except for recent bouts of chickenpox 1 week to 3 months prior to hospitalization. Three children presented with parkinsonian manifestations. Bilateral, symmetric hypodense, nonenhancing basal ganglia lesions were found on CT. These areas showed nonenhancing low signal intensity on T1-weighted images and high signal intensity on T2-weighted images on MR. One child presented with diffuse, multiple gray and white matter lesions of similar imaging characteristics; some lesions, however, did enhance. This child had no gait disturbances. Post-varicella encephalitis can produce two patterns of dramatic CT and MR findings. With an appropriate history and clinical findings, varicella as a cause of bilateral basal ganglia or diffuse cerebral lesions can be differentiated from other possible etiologies which include trauma, anoxia, metabolic disorders and demyelinating diseases. (orig.)

Solid models for CT/MR image display

International Nuclear Information System (INIS)

ManKovich, N.J.; Yue, A.; Kioumehr, F.; Ammirati, M.; Turner, S.

1991-01-01

Medical imaging can now take wider advantage of Computer-Aided-Manufacturing through rapid prototyping technologies (RPT) such as stereolithography, laser sintering, and laminated object manufacturing to directly produce solid models of patient anatomy from processed CT and MR images. While conventional surgical planning relies on consultation with the radiologist combined with direct reading and measurement of CT and MR studies, 3-D surface and volumetric display workstations are providing a more easily interpretable view of patient anatomy. RPT can provide the surgeon with a life size model of patient anatomy constructed layer by layer with full internal detail. The authors have developed a prototype image processing and model fabrication system based on stereolithography, which provides the neurosurgeon with models of the skull base. Parallel comparison of the mode with the original thresholded CT data and with a CRT displayed surface rendering showed that both have an accuracy of >99.6 percent. The measurements on the surface rendered display proved more difficult to exactly locate and yielded a standard deviation of 2.37 percent. This paper presents an accuracy study and discusses ways of assessing the quality of neurosurgical plans when 3-D models re made available as planning tools

Comparison of radiography, CT and MR imaging in detection of arthropathies in patients with hemophilia

International Nuclear Information System (INIS)

Yu Wei; Lin Qiang; Shang Wei; Zhu Haifeng; Meng Wei; Xu Ruiyi; Zhao Yongqiang; Shi Yongsheng

2007-01-01

Objective: To compare MR, CT, and radiography in the detection of arthropathies in patients with hemophilia. Methods: Forty-one symptomic joint images in the 14 patients with hemophilia, aged from 11 to 24 years, were used in this study. Each joint had the examinations of radiography, CT and MR within one day. The severity of each joint was staged using conventional radiographic classification. Severe HA patients with stage 5 were excluded from the study. Imaging findings of soft tissue swelling, osteoporosis, epiphyseal overgrowth, joint erosion, cyst, joint space narrowing, bone marrow, joint effusion, hemorrhage, synovial hypertrophy, widened intercondylar notch as well as anterior and posterior cruciate ligaments (only for knee joint) were used for the all imaging comparison. Results: The 41 symptomatic joints in 14 patients with hemophilia were classified by radiographic criteria into stage 0 (n=5), stage 1 (n=7), stage 2 (n=6), stage 3 (n=8) and stage 4 (n=15). Soft tissue swelling or joint effusion was observed in 33 joints by radiographs, in 34 joints by both CT and MR. Joint erosions were demonstrated in 34 joints by MR, in 33 joints by CT and 20 joints by radiographs. Joint cysts were shown in 21 joints by MR, in 18 joints by CT and 9 joints by radiographs. Significant differences in detection of erosion and cyst were found between radiography with either CT (P 0.05). MR showed improvement for detecting more foci of both erosion and cyst than CT and radiography, and also CT showed the improvement than radiography. Bone marrow edema 14 joints, hemorrhage in 34 joints and synovial hypertrophy in 27 joints were revealed on MR images. Conclusion: MRI is superior to CT and conventional radiography in detecting the abnormal changes and should be considered as the first choice among the imaging modalities in evaluating hemophilic arthropathies. (authors)

3D-MR vs. 3D-CT of the shoulder in patients with glenohumeral instability

Energy Technology Data Exchange (ETDEWEB)

Stillwater, Laurence; Koenig, James; Maycher, Bruce; Davidson, Michael [University of Manitoba, Winnipeg (Canada)

2017-03-15

To determine whether 3D-MR osseous reformats of the shoulder are equivalent to 3D-CT osseous reformats in patients with glenohumeral instability. Patients with glenohumeral instability, who were to be imaged with both CT and MRI, were prospectively selected. CT and MR were performed within 24 h of one another on 12 shoulders. Each MR study included an axial 3D isotropic VIBE sequence. The image data from the isotropic VIBE sequence were post-processed using subtraction and 3D software. CT data were post-processed using 3D software. The following measurements were obtained for both 3D-CT and 3D-MR post-processed images: height and width of the humeral head and glenoid, Hill-Sachs size and percent humeral head loss (if present), size of glenoid bone loss and percent glenoid bone loss (if present). Paired t-tests and two one-sided tests for equivalence were used to assess the differences between imaging modalities and equivalence. The measurement differences from the 3D-CT and 3D-MR post-processed images were not statistically significant. The measurement differences for humeral height, glenoid height and glenoid width were borderline statistically significant; however, using any adjustment for multiple comparisons, this failed to be significant. Using an equivalence margin of 1 mm for measurements and 1.5% for percent bone loss, the 3D-MR and 3D-CT post-processed images were equivalent. Three-dimensional-MR osseous models of the shoulder using a 3D isotropic VIBE sequence were equivalent to 3D-CT osseous models, and the differences between modalities were not statistically significant. (orig.)

Magnetic resonance (MR) imaging in delayed encephalopathy of acute carbon monoxide poisoning - comparison with CT -

International Nuclear Information System (INIS)

Chang, Kee Hyun; Suh, Chang Hae; Choo, In Wook

1986-01-01

Eleven magnetic resonance (MR) and computed tomographic (CT) imaging were performed in nine patients with mild to moderate degree of delayed neuropsychiatric symptoms following acute carbon monoxide (CO) poisoning, to evaluate the capability of MR in demonstrating any additional finding to CT. The MR images were obtained using 0.15 Tesla resistive system with various combination of three pulse sequences, including partial saturation recovery, T2-weighted spin echo and inversion recovery. Bilateral white matter abnormalities suggesting demyelination were demonstrated in 4 patients with MR and in only 2 patients with CT. The contrast discrimination between normal and abnormal white matter proved to be better with T2-weighted spin echo and inversion recovery than with partial saturation recovery and CT. But necrosis of the globus pallidus (1 patient) and diffuse atrophy (3 patients) were equally demonstrated on both MR and CT. It is suggested that MR be used as a initial imaging method in the evaluation of the delayed encephalopathy following acute CO poisoning, especially for the detection of the possible white matter lesions. Acute carbon monoxide (CO) poisoning produces hypoxia by displacing oxygen from hemoglobin and preventing its release from hemoglobin in tissues, often resulting in fetal event. Victims who survive acute CO poisoning may have various delayed symptoms and signs. Occasionally, an apparent recovery is followed within two days to three weeks by a sudden neurological deterioration. The degree of neuropsychiatric symptoms depends upon the extent and severity of the pathologic changes in the brain. The pathologic effects of CO poisoning are present in almost all organs of patients. However, the most important changes occur in the brain, which consist of necrosis of the globus pallidus and reticular zone of the substantia nigra, and the degeneration of the cerebral white matter. The diagnostic superiority of magnetic resonance (MR) over CT has already

Static-dynamic MR urography. Comparison with excretory urography and scintigraphy in experimentally induced urinary tract obstruction (UTO); Statisch-dynamische MR-Urographie. Vergleich mit Ausscheidungsurographie und Szintigraphie bei experimentell induzierter Harntransportstoerung (HTS)

Energy Technology Data Exchange (ETDEWEB)

Rohrschneider, W.K.; Wunsch, R.; Troeger, J. [Paediatrische Radiologie, Univ. Heidelberg (Germany); Hoffend, J. [Nuklearmedizinische Klinik, Univ. Heidelberg (Germany); Becker, K. [Inst. fuer Versuchstierkunde, Univ. Heidelberg (Germany); Darge, K.; Clorius, J.H. [Kooperationseinheit Nuklearmedizin, Deutsches Krebsforschungszentrum, Heidelberg (Germany); Kooijman, H. [Philips Medizin-Systeme, Hamburg (Germany)

2001-02-01

Purpose: To assess the diagnostic value of combined static-dynamic MR urography (MRU) for the functional-morphological evaluation of experimentally induced urinary tract obstruction. Methods: Static-dynamic MRU - combination study with a respiratory-triggered 3D-IR-TSE sequence and a dynamic 2D-FFE sequence after Gd-DTPA and furosemide - was obtained in comparison with {sup 99m}Tc-MAG3 diuretic renal scintigraphy (DRS), excretory urography (EU) and ultrasound (US) in 29 healthy piglets and in 20 piglets with surgically induced ureteric stenosis (total of 50 postoperative examination blocks). Results: MRU allowed complete depiction of the urinary tract in all controls, in operated piglets the stenosis was always correctly identified. Quality of MRU was superior to EU in 36 to 43 comparative studies. Calculation of single kidney function from parenchymal renograms, and assessment of urinary excretion from whole-kidney renograms resulted in a highly significant agreement of MRU with DRS. Conclusion: Static-dynamic MR urography allows excellent depiction of experimentally induced urinary tract obstruction, and reliable assessment of individual renal function and urinary excretion. Two advantages of the method stand out, it does not require radiation and it permits a functional-morphological correlation. (orig.) [German] Ziel: Einschaetzung der Wertigkeit der kombinierten statisch-dynamischen MR-Urographie (MRU) zur umfassenden funktionell-morphologischen Diagnostik tierexperimentell induzierter Harntransportstoerungen. Methodik: Die statisch-dynamische MRU-Kombination aus einer atemgetriggerten 3D-IR-TSE-Sequenz und einer dynamischen 2D-FFE-Sequenz nach Gd-DTPA und Furosemid - wurde im Vergleich zu {sup 99m}Tc-MAG3-Diurese-Nierenszintigraphie (DNS), Ultraschall (US) und Ausscheidungsurographie (AUG) bei 29 gesunden Ferkeln sowie bei 20 Ferkeln mit operativ indizierter Harnwegsstenose (insgesamt 50 postoperative Untersuchungsbloecke) durchgefuehrt. Ergebnisse: Die MRU

Multimodal Registration of gated cardiac PET, CT and MR sequences

International Nuclear Information System (INIS)

Baty, X.

2007-07-01

The research described in this manuscript deals with the multimodal registration of cardiac images from Magnetic Resonance Imaging (MRI), Position Emission Tomography (PET) and Computerized Tomography (CT). All these modalities are gated to the Electrocardiogram (ECG) and provide information to evaluate cardiac function, and to diagnose and to follow-up cardiovascular pathologies. PET imaging allows the evaluation of ventricular function and MRI is a gold standard for the study of the left ventricular function. The goal of our registration process is to merge functional (from PET) and anatomical images (from CT and MRI). Our process is adapted to the modalities used and is divided in two steps: (i) a global rigid 3-dimensional model-based ICP (Iterative Closest Point) registration between CT and MR data and (ii) an iconic 2-dimensional registration based on Free Form Deformations and Mutual Information. This last step presents an original contribution by using a composite image of CT (which presents epicardic contours) and PET (where endocardic contours are partially visible) data to make mutual information more accurate in representing the similarity with the MR data. To speed up the whole process, we also present a transformation initialization scheme using displacement field obtained form MR data only. The obtained results have been evaluated by experts. (author)

Thoracic intradural arachnoid cyst: Possible pitfalls with myelo-CT and MR

International Nuclear Information System (INIS)

Dietemann, J.L.; Filippi de la Palavesa, M.M.; Kastler, B.; Warter, J.M.; Buchheit, F.

1991-01-01

A thoracic intradural arachnoid cyst presenting as an intradural extramedullary mass highly suggestive of psammoma on myelogram and myelo-CT is reported in a 34-year-old female. High densities of the cyst were related to collection of contrast media within the cyst. However MR examination of the thoracic spinal cord including sagittal T1 (without and with contrast) and T2 studies failed to demonstrate the mass. Lack of MR changes were related on one hand to the small size of the cyst and to the absence of mass effect on the spinal cord, and on the other hand to a CSF-like signal of the contents of the cyst. Only combination of myelography, myelo-CT and MR allows precise diagnosis of small intradual arachnoid cysts; however MR is the method of choice for evaluation of large intradural subarachnoid cysts. (orig.)

Early clinical phase of patient's management after polytrauma using 1- and 4-slice helical CT; Fruehes klinisches Management nach Polytrauma mit 1- und 4-Schicht-Spiral-CT

Energy Technology Data Exchange (ETDEWEB)

Kloeppel, R.; Kahn, T. [Klinik und Poliklinik fuer Diagnostische Radiologie, Universitaetsklinikum Leipzig (Germany); Schreiter, D. [Chirurgische Intensivtherapieabteilung, Zentrum fuer Chirurgie, Universitaetsklinikum Leipzig (Germany); Dietrich, J. [Abt. Neuroradiologie der Klinik und Poliklinik fuer Diagnostische Radiologie, Universitaetsklinikum Leipzig (Germany); Josten, C. [Klinik und Poliklinik fuer Unfall- und Wiederherstellungschirurgie, Zentrum fuer Chirurgie, Universitaetsklinikum Leipzig (Germany)

2002-07-01

In the early clinical phase the comprehensive imaging of patients with multiple trauma using helical CT is already established. Aim of this study was to assess whether MSCT may improve the patient management and the diagnostic results.The procedure is designed as follows: after life-thretening treatment x-ray of chest and ultrasound are carried out in the emergency room. Then the patient is moved to CT. From 1998 to december 2000 241 patients were examined using a single slice helical CT (Somatom plus 4), in 2001 79 patients using a 4-slice helical CT (Somatom VZ, Siemens Med.Sol.). After CT selected radiograms of the extremities were taken.359 of 360 procedures were carried out successfully. Excluding 1 case (death during 1-sl. h CT) all relevant lesions of head, neck, and body were diagnosed. Although the patients had an injury severity score of {approx}30. The change from 1slice-helical CT to 4 slice-helical CT allowed us to reduce the stay in the CT room from 28 to 16 min. The total lethality decreased by {approx}4%.Advantages for the patient arose from the standardized examination protocol using multislice CT. If integrated in an interdisciplinary management concept, it is a good compromise between examination time, comprehensive diagnostic imaging, life-saving therapeutic procedures, and therapy planning. (orig.) [German] Die klinische Erstversorgung Polytraumatisierter schliesst inzwischen in vielen Unfallkliniken den fruehzeitigen Einsatz der Spiral-CT ein. Kann die neuerlich eingefuehrte Mehrschicht-Spiral-CT Ergebnisse und Patientenmanagement weiter verbessern?Nach lebensrettenden Sofortmassnahmen, Thoraxroentgen und Notsonographie im Schockraum erfolgte die CT: Von 1998-2000 wurden 241 Patienten mit einem 1-Schicht-Spiral-CT (Somatom plus 4) und in 2001 79 Patienten mit einem 4-Schicht-Spiral-CT (Somatom VZ, beide Siemens Med. Sol.) untersucht. Klinisch ausgewaehlte Extremitaetenaufnahmen wurden ergaenzt.359 von 360 Untersuchungen verliefen erfolgreich

Evaluation of pleural disease using MR and CT: With special reference to malignant pleural mesothelioma

International Nuclear Information System (INIS)

Knuuttila, A.; Kivisaari, L.; Kivisaari, A.; Palomaeki, M.; Tervahartiala, P.; Mattson, K.

2001-01-01

Purpose: To evaluate MR imaging and CT in differentiating malignant pleural mesothelioma from other malignancies or benign pleural disease. Material and Methods: Thirty-four patients (18 pleural mesothelioma, 9 other malignancies, 7 benign pleural diseases) were examined using enhanced CT and MR. Two radiologists reviewed the CT and two others the MR images. Comparisons were made between the diagnostic groups and the imaging methods. Results: The abnormalities commonly found in malignant disease, but significantly less frequently in benign pleural disease, were focal thickening and enhancement of inter lobar fissures. In mesothelioma, enhancement of inter lobar fissures, tumour invasion of the diaphragm, mediastinal soft tissue or chest wall, were significantly more often observed than in other malignancies and MR was the most sensitive method. In other malignancies, invasion of bony structures was a more common finding and was also better shown by MR. The contrast-enhanced T1 fat-suppressed (CET1fs) sequence detected these features better than other MR sequences. Conclusion: MR, especially the CET1fs sequence in three planes, gave more information than enhanced CT. Focal thickening and enhancement of inter lobar fissures were early abnormalities indicating malignant pleural disease. MR could be clinically useful for differentiating mesothelioma from other pleural diseases

Evaluation of pleural disease using MR and CT: With special reference to malignant pleural mesothelioma

Energy Technology Data Exchange (ETDEWEB)

Knuuttila, A. [Helsinki Univ. Central Hospital (Finland). Dept. of Medicine; Kivisaari, L.; Kivisaari, A.; Palomaeki, M.; Tervahartiala, P. [Helsinki Univ. Central Hospital (Finland). Dept. of Radiology; Mattson, K. [Helsinki Univ. Central Hospital (Finland). Dept. of Medicine

2001-09-01

Purpose: To evaluate MR imaging and CT in differentiating malignant pleural mesothelioma from other malignancies or benign pleural disease. Material and Methods: Thirty-four patients (18 pleural mesothelioma, 9 other malignancies, 7 benign pleural diseases) were examined using enhanced CT and MR. Two radiologists reviewed the CT and two others the MR images. Comparisons were made between the diagnostic groups and the imaging methods. Results: The abnormalities commonly found in malignant disease, but significantly less frequently in benign pleural disease, were focal thickening and enhancement of inter lobar fissures. In mesothelioma, enhancement of inter lobar fissures, tumour invasion of the diaphragm, mediastinal soft tissue or chest wall, were significantly more often observed than in other malignancies and MR was the most sensitive method. In other malignancies, invasion of bony structures was a more common finding and was also better shown by MR. The contrast-enhanced T1 fat-suppressed (CET1fs) sequence detected these features better than other MR sequences. Conclusion: MR, especially the CET1fs sequence in three planes, gave more information than enhanced CT. Focal thickening and enhancement of inter lobar fissures were early abnormalities indicating malignant pleural disease. MR could be clinically useful for differentiating mesothelioma from other pleural diseases.

Comparison of CT enterography and MR enterography imaging features of active Crohn disease in children and adolescents

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Gale, Heather I. [The Warren Alpert Medical School of Brown University, Department of Diagnostic Imaging, Rhode Island Hospital/Hasbro Children' s Children' s Hospital/Women and Infants Hospital, Providence, RI (United States); Sharatz, Steven M.; Nimkin, Katherine; Gee, Michael S. [MassGeneral Hospital for Children, Division of Pediatric Imaging, Department of Radiology, Harvard Medical School, Boston, MA (United States); Taphey, Mayureewan [Bumrungrad International Hospital, Bangkok (Thailand); Bradley, William F. [Cambridge Mobile Telematics, Cambridge, MA (United States)

2017-09-15

Assessment for active Crohn disease by CT enterography and MR enterography relies on identifying mural and perienteric imaging features. To evaluate the performance of established imaging features of active Crohn disease in children and adolescents on CT and MR enterography compared with histological reference. We included patients ages 18 years and younger who underwent either CT or MR enterography from 2007 to 2014 and had endoscopic biopsy within 28 days of imaging. Two pediatric radiologists blinded to the histological results reviewed imaging studies and scored the bowel for the presence or absence of mural features (wall thickening >3 mm, mural hyperenhancement) and perienteric features (mesenteric hypervascularity, edema, fibrofatty proliferation and lymphadenopathy) of active disease. We performed univariate analysis and multivariate logistic regression to compare imaging features with histological reference. We evaluated 452 bowel segments (135 from CT enterography, 317 from MR enterography) from 84 patients. Mural imaging features had the highest association with active inflammation both for MR enterography (wall thickening had 80% accuracy, 69% sensitivity and 91% specificity; mural hyperenhancement had 78%, 53% and 96%, respectively) and CT enterography (wall thickening had 84% accuracy, 72% sensitivity and 91% specificity; mural hyperenhancement had 76%, 51% and 91%, respectively), with perienteric imaging features performing significantly worse on MR enterography relative to CT enterography (P < 0.001). Mural features are predictors of active inflammation for both CT and MR enterography, while perienteric features can be distinguished better on CT enterography compared with MR enterography. This likely reflects the increased conspicuity of the mesentery on CT enterography and suggests that mural features are the most reliable imaging features of active Crohn disease in children and adolescents. (orig.)

Optimization of the Contrast Mixture Ratio for Simultaneous Direct MR and CT Arthrography: an in Vitro Study

International Nuclear Information System (INIS)

Choi, Ja Young; Hong, Sung Hwan; Kim, Na Ra; Jun, Woo Sun; Moon, Sung Gyu; Kang, Heung Sik; Lee, Joon Woo; Choi, Jung Ah

2008-01-01

This study was designed to determine the optimal mixture ratio of gadolinium and iodinated contrast agent for simultaneous direct MR arthrography and CT arthrography. An in vitro study was performed utilizing mixtures of gadolinium at six different concentrations (0.625, 1.25, 2.5, 5.0, 10 and 20 mmol/L) and iodinated contrast agent at seven different concentrations (0, 12.5, 25, 37.5, 50, 75 and 92-99.9%). These mixtures were placed in tissue culture plates, and were then imaged with CT and MR (with T1-weighted sequences, proton-density sequences and T2-weighted sequences). CT numbers and signal intensities were measured. Pearson's correlation coefficients were used to assess the correlations between the gadolinium/iodinated contrast agent mixtures and the CT numbers/MR signal intensities. Scatter diagrams were plotted for all gadolinium/iodinated contrast agent combinations and two radiologists in consensus identified the mixtures that yielded the optimal CT numbers and MR signal intensities. The CT numbers showed significant correlation with iodinated contrast concentrations (r = 0.976, p < 0.001), whereas the signal intensities as measured on MR images showed a significant correlation with both gadolinium and iodinated contrast agent concentrations (r = -484 to -0.719, p < 0.001). A review of the CT and MR images, graphs, and scatter diagram of 42 combinations of the contrast agent showed that a concentration of 1.25 mmol/L gadolinium and 25% iodinated contrast agent was the best combination for simultaneous CT and MR imaging. A mixture of 1.25 mmol/L gadolinium and 25% iodinated contrast agent was found to be optimal for simultaneous direct MR arthrography and CT arthrography

Perfusion abnormalities in congenital and neoplastic pulmonary disease: comparison of MR perfusion and multislice CT imaging

International Nuclear Information System (INIS)

Boll, Daniel T.; Lewin, Jonathan S.; Young, Philip; Gilkeson, Robert C.; Siwik, Ernest S.

2005-01-01

The aim of this work was to assess magnetic resonance (MR) perfusion patterns of chronic, nonembolic pulmonary diseases of congenital and neoplastic origin and to compare the findings with results obtained with pulmonary, contrast-enhanced multislice computed tomography (CT) imaging to prove that congenital and neoplastic pulmonary conditions require MR imaging over the pulmonary perfusion cycle to successfully and directly detect changes in lung perfusion patterns. Twenty-five patients underwent concurrent CT and MR evaluation of chronic pulmonary diseases of congenital (n=15) or neoplastic (n=10) origin. Analysis of MR perfusion and contrast-enhanced CT datasets was realized by defining pulmonary and vascular regions of interest in corresponding positions. MR perfusion calculated time-to-peak enhancement, maximal enhancement and the area under the perfusion curve. CT datasets provided pulmonary signal-to-noise ratio measurements. Vessel centerlines of bronchial arteries were determined. Underlying perfusion type, such as pulmonary arterial or systemic arterial supply, as well as regions with significant variations in perfusion were determined statistically. Analysis of the pulmonary perfusion pattern detected pulmonary arterial supply in 19 patients; six patients showed systemic arterial supply. In pulmonary arterial perfusion, MR and multislice CT imaging consistently detected the perfusion type and regions with altered perfusion patterns. In bronchial arterial supply, MR perfusion and CT imaging showed significant perfusion differences. Patients with bronchial arterial supply had bronchial arteries ranging from 2.0 to 3.6 mm compared with submillimeter diameters in pulmonary arterial perfusion. Dynamic MR imaging of congenital and neoplastic pulmonary conditions allowed characterization of the pulmonary perfusion type. CT imaging suggested the presence of systemic arterial perfusion by visualizing hypertrophied bronchial arteries. (orig.)

MR-guided pain therapy: principles and clinical applications; MR-gesteuerte Schmerztherapie: Prinzipien und klinische Applikationen

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Fritz, J.; Pereira, P.L. [Diagnostische Radiologie, Eberhard-Karls-Universitaet, Tuebingen (Germany)

2007-09-15

X-ray fluoroscopy and computed tomography are frequently used to perform percutaneous interventions in pain therapy. The development of MR-compatible therapy needles now allows these interventions to be performed under MR imaging guidance. MR-guided interventions may be performed using most clinical MR scanners; however, systems with an open configuration are advantageous. Multiplanar pre- and intra-procedural MR imaging provides the interventionalist with essential information, such as evaluation of anatomy and pathology, as well as the planning of the procedure and monitoring of fluid distribution without the use of contrast agents. With the use of non-ionizing radiation, interventional MR imaging is especially suited for the treatment of children and young adults as well as for serial injection therapy. For spinal MR interventions, passive needle visualization is an easily achievable and reliable method. The resulting needle artifact is influenced by several factors such as the alloy of the needle, the strength of the static magnetic field, the sequence type, the spatial orientation of the therapy needle as well as the echo time and may further be optimized during the intervention by alteration of the last three factors. Fast acquisition techniques and image processing allow for continuous, near real-time MR imaging (so-called MR fluoroscopy) and interactive needle navigations, comparable to X-ray fluoroscopy and CT fluoroscopy. The purpose of this review is to illustrate and discuss general concepts of interventional MR imaging. A spectrum of interventional MR imaging procedures in spinal pain therapy is described and illustrated, including procedures such as lumbar facet joint injections, sacroiliac joint injections, lumbar spinal nerve root infiltrations and drug delivery to the lumbar sympathetic chain. (orig.)

Magnetic resonance imaging of sacroiliitis: anatomy, histological pathology, MR-morphology, and grading; Magnetresonanztomographie der Sakroiliitis: Anatomie, Pathohistologie, MR-Morphologie und Graduierung

Energy Technology Data Exchange (ETDEWEB)

Hermann, K.G.A.; Fischer, T. [Institut fuer Radiologie, Charite Universitaetsmedizin Berlin (Germany); Braun, J. [Rheumazentrum Ruhrgebiet, St. Josefs-Krankenhaus, Herne (Germany); Reisshauer, H. [Gemeinschaftspraxis fuer Pathologie, Neubrandenburg (Germany); Bollow, M. [Institut fuer Radiologie, Augusta-Kranken-Anstalt, Bochum (Germany)

2004-03-01

The diagnosis of spondyloarthropathy is based on radiography of the sacroiliac joints, beside the patient's history and clinical examination. In cases where the clinical examination and radiography yield discrepant findings, contrast-enhanced magnetic resonance imaging (MRI) is a sensitive modality for the diagnosis of early sacroiliitis. Knowledge of the morphologic anatomy of the sacroiliac joints and of their abnormal micro- and macroanatomy in sacroiliitis and enthesitis are helpful for interpreting MR images. Arthritis of the sacroiliac joints is characterized by subchondral sclerosis, erosions, transarticular bone bridges, accumulation of periarticular fat, juxta-articular osteitis, synovitis, capsulitis, and enthesitis. The major histologic finding in active sacroiliitis is the presence of proliferative, pannus-like connective tissue destroying cartilage and bone. This tissue contains fibroblasts and fibrocytes as well as T cells and macrophages with a shift of the CD4/CD8 ratio toward the CD4 T helper cell population. The well-established grading of MRI findings by means of a chronicity and activity index, which are determined quantitatively from dynamic MR images, is supplemented by an alternative, semiquantitative grading of activity. The following grades were defined for the short tau inversion recovery (STIR) sequence or the T1-weighted, fat-saturated spin-echo sequence for each quadrant (iliac anterior, iliac posterior, sacral anterior, sacral posterior):0: no signal increase,1: local signal increase in the joint cavity or within erosions,2: small areas of increased juxta-articular signal,3: moderate sized areas of increased juxta-articular signal,4: large areas of increased juxta-articular signal.Values of the 4 quadrants are summed to an activity score (range 0-16). The new grading system is proposed to facilitate the examination and shorten image interpretation time. (orig.) [German] Neben Anamnese und klinischer Untersuchung bildet das

Evaluation of Dixon Sequence on Hybrid PET/MR Compared with Contrast-Enhanced PET/CT for PET-Positive Lesions

International Nuclear Information System (INIS)

Jeong, Ju Hye; Cho, Ihn Ho; Kong, Eun Jung; Chun, Kyung Ah

2014-01-01

Hybrid positron emission tomography and magnetic resonance (PET/MR) imaging performs a two-point Dixon MR sequence for attenuation correction. However, MR data in hybrid PET/MR should provide anatomic and morphologic information as well as an attenuation map. We evaluated the Dixon sequence of hybrid PET/MR for anatomic correlation of PET-positive lesions compared with contrast-enhanced PET/computed tomography (CT) in patients with oncologic diseases. Twelve patients underwent a single injection, dual imaging protocol. PET/CT was performed with an intravenous contrast agent (85±13 min after 18 F-FDG injection of 403± 45 MBq) and then (125±19 min after injection) PET/MR was performed. Attenuation correction and anatomic allocation of PET were performed using contrast-enhanced CT for PET/CT and Dixon MR sequence for hybrid PET/MR. The Dixon MR sequence and contrast-enhanced CT were compared for anatomic correlation of PET-positive lesions (scoring scale ranging from 0 to 3 for visual ratings). Additionally, standardized uptake values (SUVs) for the detected lesions were assessed for quantitative comparison. Both hybrid PET/MR and contrast-enhanced PET/CT identified 55 lesions with increased FDG uptake in ten patients. In total, 28 lymph nodes, 11 bone lesions, 3 dermal nodules, 3 pleural thickening lesions, 2 thyroid nodules, 1 pancreas, 1 liver, 1 ovary, 1 uterus, 1 breast, 1 soft tissue and 2 lung lesions were present. The best performance was observed for anatomic correlation of PET findings by the contrast-enhanced CT scans (contrast-enhanced CT, 2.64± 0.70; in-phase, 1.29±1.01; opposed-phase, 1.29±1.15; water-weighted, 1.71±1.07; fat weighted, 0.56±1.03). A significant difference was observed between the scores obtained from the contrast-enhanced CT and all four coregistered Dixon MR images. Quantitative evaluation revealed a high correlation between the SUVs measured with hybrid PET/MR (SUVmean, 2.63±1.62; SUVmax, 4.30±2.88) and contrast-enhanced PET/CT

Evaluation of Dixon Sequence on Hybrid PET/MR Compared with Contrast-Enhanced PET/CT for PET-Positive Lesions

Energy Technology Data Exchange (ETDEWEB)

Jeong, Ju Hye; Cho, Ihn Ho; Kong, Eun Jung; Chun, Kyung Ah [Yeungnam Univ. Hospital, Daegu (Korea, Republic of)

2014-03-15

Hybrid positron emission tomography and magnetic resonance (PET/MR) imaging performs a two-point Dixon MR sequence for attenuation correction. However, MR data in hybrid PET/MR should provide anatomic and morphologic information as well as an attenuation map. We evaluated the Dixon sequence of hybrid PET/MR for anatomic correlation of PET-positive lesions compared with contrast-enhanced PET/computed tomography (CT) in patients with oncologic diseases. Twelve patients underwent a single injection, dual imaging protocol. PET/CT was performed with an intravenous contrast agent (85±13 min after {sup 18}F-FDG injection of 403± 45 MBq) and then (125±19 min after injection) PET/MR was performed. Attenuation correction and anatomic allocation of PET were performed using contrast-enhanced CT for PET/CT and Dixon MR sequence for hybrid PET/MR. The Dixon MR sequence and contrast-enhanced CT were compared for anatomic correlation of PET-positive lesions (scoring scale ranging from 0 to 3 for visual ratings). Additionally, standardized uptake values (SUVs) for the detected lesions were assessed for quantitative comparison. Both hybrid PET/MR and contrast-enhanced PET/CT identified 55 lesions with increased FDG uptake in ten patients. In total, 28 lymph nodes, 11 bone lesions, 3 dermal nodules, 3 pleural thickening lesions, 2 thyroid nodules, 1 pancreas, 1 liver, 1 ovary, 1 uterus, 1 breast, 1 soft tissue and 2 lung lesions were present. The best performance was observed for anatomic correlation of PET findings by the contrast-enhanced CT scans (contrast-enhanced CT, 2.64± 0.70; in-phase, 1.29±1.01; opposed-phase, 1.29±1.15; water-weighted, 1.71±1.07; fat weighted, 0.56±1.03). A significant difference was observed between the scores obtained from the contrast-enhanced CT and all four coregistered Dixon MR images. Quantitative evaluation revealed a high correlation between the SUVs measured with hybrid PET/MR (SUVmean, 2.63±1.62; SUVmax, 4.30±2.88) and contrast

MRI, CT, and sonography in the preoperative evaluation of primary tumor extension in malignant pleural mesothelioma; MRT, CT und Sonographie in der praeoperativen Beurteilung der Primaertumorausdehnung beim malignen Pleuramesotheliom

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Layer, G.; Steudel, A.; Schild, H.H. [Radiologische Universitaetsklinik Bonn (Germany); Schmitteckert, H.; Tuengerthal, S.; Schirren, J. [Thoraxklinik Heidelberg-Rohrbach (Germany); Kaick, G. van [Deutsches Krebsforschungszentrum Heidelberg (Germany). Schwerpunkt fuer Onkologische Diagnostik und Therapie

1999-04-01

Purpose: Evaluation of the diagnostic value of the imaging modalities computed tomography (CT), magnetic resonance imaging (MRI), and thoracic sonography in the preoperative staging of malignant pleural mesothelioma. Results: The accuracy rates for CT were 85%, 98%, 83%, 73%, 71%, and 83%. MRI had an accuracy of 71%, 92%, 71%, 83%, 71%, and 96%, the thoracic ultrasound examinations of 76%, 63%, 51%, 60%, 71% and 89%. Conclusions: According to these results CT remains the method of choice in the preoperative assessment of T-stage of malignant pleural mesothelioma. MRI is of nearly the same value, but is not a must. Sonography may be supplementary method for operation planning. (orig./AJ) [Deutsch] Ziel: Evaluation der diagnostischen Wertigkeit der Schnittbildverfahren MRT, CT und Sonographie in der praeoperativen Diagnostik des Pleuramesothelioms. Ergebisse: Die Treffsicherheiten betrugen fuer die genannten anatomischen Regionen im CT 85%, 98%, 83%, 73%, 71%, und 83%, im MRT 71%, 92%, 71%, 83%, 71% bzw. 96%, waehrend sich fuer die thorakale Ultraschalluntersuchung Treffsicherheiten von 76%, 63%, 51%, 60%, 71% und 89% errechneten. Schlussfolgerungen: Die CT bleibt damit das Verfahren erster Wahl in der praeoperativen Diagnostik des malignen Pleuramesothelioms. Eine unbedingte Forderung nach praeoperativer Durchfuehrung einer MRT-Untersuchung ergibt sich nach der vorliegenden Studie nicht. Die Sonographie des Thorax und oberen Abdomens liefert einen wichtigen ergaenzenden Beitrag bei der Planung der Operation des malignen Pleuramesothelioms. (orig./AJ)

Prospective Comparison of the Diagnostic Accuracy of MR Imaging versus CT for Acute Appendicitis.

Science.gov (United States)

Repplinger, Michael D; Pickhardt, Perry J; Robbins, Jessica B; Kitchin, Douglas R; Ziemlewicz, Tim J; Hetzel, Scott J; Golden, Sean K; Harringa, John B; Reeder, Scott B

2018-04-24

Purpose To compare the accuracy of magnetic resonance (MR) imaging with that of computed tomography (CT) for the diagnosis of acute appendicitis in emergency department (ED) patients. Materials and Methods This was an institutional review board-approved, prospective, observational study of ED patients at an academic medical center (February 2012 to August 2014). Eligible patients were nonpregnant and 12- year-old or older patients in whom a CT study had been ordered for evaluation for appendicitis. After informed consent was obtained, CT and MR imaging (with non-contrast material-enhanced, diffusion-weighted, and intravenous contrast-enhanced sequences) were performed in tandem, and the images were subsequently retrospectively interpreted in random order by three abdominal radiologists who were blinded to the patients' clinical outcomes. Likelihood of appendicitis was rated on a five-point scale for both CT and MR imaging. A composite reference standard of surgical and histopathologic results and clinical follow-up was used, arbitrated by an expert panel of three investigators. Test characteristics were calculated and reported as point estimates with 95% confidence intervals (CIs). Results Analysis included images of 198 patients (114 women [58%]; mean age, 31.6 years ± 14.2 [range, 12-81 years]; prevalence of appendicitis, 32.3%). The sensitivity and specificity were 96.9% (95% CI: 88.2%, 99.5%) and 81.3% (95% CI: 73.5%, 87.3%) for MR imaging and 98.4% (95% CI: 90.5%, 99.9%) and 89.6% (95% CI: 82.8%, 94.0%) for CT, respectively, when a cutoff point of 3 or higher was used. The positive and negative likelihood ratios were 5.2 (95% CI: 3.7, 7.7) and 0.04 (95% CI: 0, 0.11) for MR imaging and 9.4 (95% CI: 5.9, 16.4) and 0.02 (95% CI: 0.00, 0.06) for CT, respectively. Receiver operating characteristic curve analysis demonstrated that the optimal cutoff point to maximize accuracy was 4 or higher, at which point there was no difference between MR imaging and CT

The quantification of glenoid bone loss in anterior shoulder instability; MR-arthro compared to 3D-CT

International Nuclear Information System (INIS)

Markenstein, Jeroen E.; Jaspars, Kjell C.C.J.; Hulst, Victor P.M. van der; Willems, W.J.

2014-01-01

The purpose of this study is to investigate if magnetic resonance imaging with intra-articular contrast (MR-arthro) is as reliable as three-dimensionally reconstructed computed tomography imaging (3D-CT) in quantifying the glenoid bone loss in patients with anterior shoulder instability. Thirty-five patients were included. Sagittal MR-arthro and 3D-CT images of the glenoid surface were obtained pre-operatively. Two observers measured these images twice with OsiriX software in a randomized and blinded way. The intraclass correlations (ICC) of the intra- and inter-observer reliability within one method and an additional Bland-Altman plot for calculating agreement between the two methods were obtained. The joint estimates of the intra-observer reliability, taking into account the data from both observer A and B, for 3D-CT and MR-arthro were good to excellent. The intra-observer reliability was 0.938 (95 % CI: 0.879, 0.968) for 3D-CT and 0.799 (95 % CI: 0.639, 0.837) for MR-arthro. The inter-observer reliability between the two observers within one method (3D-CT or MR-arthro) was moderate to good. 3D-CT: 0.724 (95 % CI: 0.236, 0.886) and MR-arthro: 0.534 (95 % CI: 0.128, 0.762). Comparing both the 3D-CT and MR-arthro method, a Bland-Altman plot showed satisfying differences with the majority of outcomes (89 %) within 1 SD. Good to excellent intra- and moderate to good inter-observer correlations and a satisfying Bland-Altman plot when compared to 3D-CT show tendencies that MR-arthro is reliable and valid for measuring bony defects of the glenoid. (orig.)

The quantification of glenoid bone loss in anterior shoulder instability; MR-arthro compared to 3D-CT

Energy Technology Data Exchange (ETDEWEB)

Markenstein, Jeroen E. [Onze Lieve Vrouwe Gasthuis, Department of Orthopedic Surgery, Postbox 95500, Amsterdam (Netherlands); Jaspars, Kjell C.C.J. [Van Weel-Bethesda Ziekenhuis, Department of Orthopedic Surgery, Dirksland (Netherlands); Hulst, Victor P.M. van der [Onze Lieve Vrouwe Gasthuis, Department of Radiology, Postbox 95500, Amsterdam (Netherlands); Willems, W.J. [Delairesse Kliniek, Department of Orthopedic Surgery, Amsterdam (Netherlands)

2014-04-15

The purpose of this study is to investigate if magnetic resonance imaging with intra-articular contrast (MR-arthro) is as reliable as three-dimensionally reconstructed computed tomography imaging (3D-CT) in quantifying the glenoid bone loss in patients with anterior shoulder instability. Thirty-five patients were included. Sagittal MR-arthro and 3D-CT images of the glenoid surface were obtained pre-operatively. Two observers measured these images twice with OsiriX software in a randomized and blinded way. The intraclass correlations (ICC) of the intra- and inter-observer reliability within one method and an additional Bland-Altman plot for calculating agreement between the two methods were obtained. The joint estimates of the intra-observer reliability, taking into account the data from both observer A and B, for 3D-CT and MR-arthro were good to excellent. The intra-observer reliability was 0.938 (95 % CI: 0.879, 0.968) for 3D-CT and 0.799 (95 % CI: 0.639, 0.837) for MR-arthro. The inter-observer reliability between the two observers within one method (3D-CT or MR-arthro) was moderate to good. 3D-CT: 0.724 (95 % CI: 0.236, 0.886) and MR-arthro: 0.534 (95 % CI: 0.128, 0.762). Comparing both the 3D-CT and MR-arthro method, a Bland-Altman plot showed satisfying differences with the majority of outcomes (89 %) within 1 SD. Good to excellent intra- and moderate to good inter-observer correlations and a satisfying Bland-Altman plot when compared to 3D-CT show tendencies that MR-arthro is reliable and valid for measuring bony defects of the glenoid. (orig.)

CT an MR imaging of the paranasal sinuses in cystic fibrosis. Correlation with microbiological and histopathological results

International Nuclear Information System (INIS)

Eggesboe, H.B.; Stiris, M.

1999-01-01

Purpose: To compare CT and MR findings of the paranasal sinuses in patients with cystic fibrosis (CF) with microbiology and histopathology. Further, to compare microbiology from the maxillary sinuses, nasopharynx and sputum. Material and methods: CT and MR imaging of the paranasal sinuses were performed in 10 CF patients. Endoscopy and maxillary sinus aspirates were obtained (guided by the MR findings) and analyzed microbiologically and histologically. Samples from the nasopharynx and sputum were analyzed microbiologically. Results: CT and MR were equal in displaying the extent of soft tissue masses, which at CT were homogeneous, while MR showed heterogeneous signals. MR images also demonstrated circumscribed areas with signal void at the STIR sequence with corresponding high to intermediate signal at the T1-weighted sequence. P. aeruginosa was frequently cultured from these areas which we named the 'black hole sign'. Maxillary sinus cultures revealed the same bacteria as nasopharynx and sputum cultures combined. Conclusion: MR images were superior to CT in differentiating soft tissue masses in the paranasal sinuses in CF patients. Bacteria with potential for specialized iron uptake mechanisms were present in areas with signal void at the STIR sequence. Our hypothesis is that the MR 'black hole sign' can be explained by paramagnetic properties related to bacterial agents. (orig.)

Diagnostic imaging in polytrauma: comparison of radiation exposure from whole-body MSCT and conventional radiography with organ-specific CT; Radiologische Bildgebung beim Polytrauma: Dosisvergleich von Ganzkoerper-MSCT und konventionellem Roentgen mit organspezifischer CT

Energy Technology Data Exchange (ETDEWEB)

Wedegaertner, U.; Lorenzen, M.; Weber, C.; Adam, G. [Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Universitaetsklinikum Hamburg-Eppendorf (Germany); Nagel, H.D. [Philips Medizin Systeme GmbH, Hamburg (Germany)

2004-07-01

Purpose: To compare the radiation dose of whole-body multislice CT (MSCT) and conventional radiography with organ-specific CT in polytrauma. Materials and Methods: The whole-body MSCT encompassing brain, neck and midface, chest, abdomen and pelvis was performed on a Somatom Volume Zoom (Siemens). Conventional radiography consisted of chest and cervical, thoracic and lumbar spine in two views as well as pelvis. Polymat, Siemens. Three combinations of organ specific CT were chosen: CT examination of (1) head and cervical spine, (2) head, cervical spine and chest, (3) head, cervical spine and abdomen. The effective doses of whole-body MSCT and conventional radiography with organ-specific CT were calculated. Results: Effective doses were 20 mSv for whole-body MSCT, 2 mSv for conventional x-ray, and 5 mSv for combination (1), 8 mSv for combination (2) and (3) 16 mSv for combination (3) of the organ-specific CT. The ratio of radiation dose between whole-body MSCT and radiography was 10: 1. This ratio was reduced to 3: 1, 2: 1 and 1: 1 when a combination of radiography and CT was performed. Conclusions: Whole-body MSCT in polytrauma compared to conventional radiography with organ-specific CT induces a threefold increased dose in unfavorable situations and no increased dose in favorable situations. Nevertheless, routine use of whole-body MSCT should be critically evaluated and should be adapted to the clinical benefit. (orig.) [German] Ziel: Dosisvergleich von Ganzkoerper-MSCT und konventioneller Basisdiagnostik mit organspezifischen Ct-Untersuchungen beim Polytrauma. Material und Methoden: Die Ganzkoerper-MSCT-Untersuchung von Schaedel, Mittelgesicht, HWS sowie Thorax, Abdomen und Becken erfolgte an einem Somatom-Volume-Zoom (Siemens). Die konventionelle Bildgebung, bestehend aus Thorax, Becken, HWS, BWS und LWs, wurde an einem Siemens-Polymat durchgefuehrt. Fuer die organspezifischen CT-Untersuchungen wurden 3 Kombinationen ausgewaehlt: (1) CCT + HWS, (2) CCT + HWS

Malignant melanomas of the meninges (MR and CT)

International Nuclear Information System (INIS)

Schuknecht, B.; Nadjmi, M.; Mueller, J.

1990-01-01

Malignant melanoma of the meninges is a rare neoplasm derived from melanocytes of the cranial or spinal meninges. Histologically classified as grade IV tumours, malignant melanoma may present either as a diffuse meningeal neoplasm, first described by Virchow in 1859, or as a circumscribed tumour attached to the meninges. Although diagnosis is rarely established prior to surgery or autopsy, MR and CT may provide indispensable information probably leading to earlier diagnosis. In 4 patients, diagnosis of a primary meningeal melanoma was based on MR and CT findings and histology. Histology was obtained in 3 cases by surgery, in one patient by autopsy and showed a melanotic and an amelanotic malignant melanoma in 2 patients each. Autopsy was carried out in 3 cases after survival of 4, 5, and 18 months; in a single case, the follow-up period is almost 3 years. (orig.) [de

Pericardial and congestive heart failure diagnostic with CT-and MR-imaging

International Nuclear Information System (INIS)

Rienmueller, R.; Seiderer, M.; Doliva, R.; Kemkes, B.; Lissner, J.

1986-01-01

Angiocardiography is still considered the gold standard in the estimation of functional parameters of the heart. However because of the inferior density resolution and the draw back of superimposition of cardiac structures angiocardiography provides only limited information about non cardiac and some cardiac structures for instance: The perimyo-, endocardium, the valves, the myocardial perfusion and metabolism or coronary blood flow. The present diagnostic and prognostic validity of CT and MR in visualizing the pericardium, the left ventricular myocardium, the heart chambers and the great heart vessels in the clinical work up of patients with pericardial and congestive heart failure is demonstrated. MR is more reliable in the diagnosis of left ventricular myocardial atrophy or fibrosis than CT. Disadvantages of MR include the failure to identify endo-, myo-and pericardial calcifications. The measurable improvement in the visualization of systolic and diastolic myocardial wall thickness using MR is of marked prognostic value in the preoperative exclusion of myocardial atrophy or fibrosis in patients with pericardial constriction

Evaluation of whole-body MR to CT deformable image registration.

Science.gov (United States)

Akbarzadeh, A; Gutierrez, D; Baskin, A; Ay, M R; Ahmadian, A; Riahi Alam, N; Lövblad, K O; Zaidi, H

2013-07-08

Multimodality image registration plays a crucial role in various clinical and research applications. The aim of this study is to present an optimized MR to CT whole-body deformable image registration algorithm and its validation using clinical studies. A 3D intermodality registration technique based on B-spline transformation was performed using optimized parameters of the elastix package based on the Insight Toolkit (ITK) framework. Twenty-eight (17 male and 11 female) clinical studies were used in this work. The registration was evaluated using anatomical landmarks and segmented organs. In addition to 16 anatomical landmarks, three key organs (brain, lungs, and kidneys) and the entire body volume were segmented for evaluation. Several parameters--such as the Euclidean distance between anatomical landmarks, target overlap, Dice and Jaccard coefficients, false positives and false negatives, volume similarity, distance error, and Hausdorff distance--were calculated to quantify the quality of the registration algorithm. Dice coefficients for the majority of patients (> 75%) were in the 0.8-1 range for the whole body, brain, and lungs, which satisfies the criteria to achieve excellent alignment. On the other hand, for kidneys, Dice coefficients for volumes of 25% of the patients meet excellent volume agreement requirement, while the majority of patients satisfy good agreement criteria (> 0.6). For all patients, the distance error was in 0-10 mm range for all segmented organs. In summary, we optimized and evaluated the accuracy of an MR to CT deformable registration algorithm. The registered images constitute a useful 3D whole-body MR-CT atlas suitable for the development and evaluation of novel MR-guided attenuation correction procedures on hybrid PET-MR systems.

Mediastinal fibrosis with pulmonary artery obstruction; diagnosis and investigation with helical CT imaging including 3-dimensional reconstructions; Pulomonalarterienstenose bei aggresiver Mediastinalfibrose; Diagnostik und 3D-Darstellung mittels helikaler CT-Untersuchung

Energy Technology Data Exchange (ETDEWEB)

Kolbe, M. [Inst. fuer Diagnostische Radiologie, Kantonsspital Basel (Switzerland); Helwig, A. [Inst. fuer Diagnostische Radiologie, Kantonsspital Basel (Switzerland); Habicht, J.M. [Klinik fuer Herz-Torax-Chirurgie, Universitaetskliniken Basel (Switzerland); Steinbruch, W. [Inst. fuer Diagnostische Radiologie, Kantonsspital Basel (Switzerland)

1997-07-01

An aggressive mediastinal fibrosis was found in a 42-year-old female, suffering from dysphagia, stabbing pain in the chest, and an unclear weight loss. In this case, the rare combination of esophageal involvement, bronchial narrowing, and pulmonary artery obstruction could easily be demonstrated with a barium study and a helical CT examination including three-dimensional reconstructions. (orig.) [Deutsch] Wir stellen den Fall einer 42jaehrigen Patientin vor, welche zur Abklaerung einer zunehmenden Dysphagie, stechender Thoraxschmerzen und eines Gewichtsverlustes hospitalisiert wurde. Mittels klinischer und radiologischer Abklaerung konnte eine aggressive Mediastinalfibrose diagnostiziert werden. Die seltene Kombination einer Oesophaguseinengung mit Pulmonalarterienstenosen sowie einer Bronchuskompression konnte nichtinvasiv mittels Oesophagogramm und helikaler CT-Untersuchung zuverlaessig und schnell dargestellt werden. (orig.)

Feasibility and preliminary results of SPECT/CT arthrography of the wrist in comparison with MR arthrography in patients with suspected ulnocarpal impaction

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Strobel, Klaus [Lucerne Cantonal Hospital, Department of Nuclear Medicine and Radiology, Lucerne (Switzerland); Kantonsspital Luzern, Roentgeninstitut/Nuklearmedizin, Luzern (Switzerland); Steurer-Dober, Isabelle; Huellner, Martin W.; Sol Perez Lago, Maria del; Veit-Haibach, Patrick; Tornquist, Katharina [Lucerne Cantonal Hospital, Department of Nuclear Medicine and Radiology, Lucerne (Switzerland); Silva, Angela J. da [Advanced Molecular Imaging, Philips Healthcare, San Jose, CA (United States); Bodmer, Elvira; Wartburg, Urs von; Hug, Urs [Lucerne Cantonal Hospital, Division of Hand and Plastic Surgery, Lucerne (Switzerland)

2014-03-15

To evaluate the feasibility and performance of SPECT/CT arthrography of the wrist in comparison with MR arthrography in patients with suspected ulnocarpal impaction. This prospective study included 28 wrists of 27 patients evaluated with SPECT/CT arthrography and MR arthrography. Iodine contrast medium and gadolinium were injected into the distal radioulnar and midcarpal joints. Late-phase SPECT/CT was performed 3.5 h after intravenous injection of approximately 650 MBq {sup 99m}Tc-DPD. MR and SPECT/CT images were separately reviewed in relation to bone marrow oedema, radionuclide uptake, and tears in the scapholunate (SL) and lunotriquetral (LT) ligaments and triangular fibrocartilage complex (TFCC), and an overall diagnosis of ulnar impaction. MR, CT and SPECT/CT imaging findings were compared with each other, with the surgical findings in 12 patients and with clinical follow-up. The quality of MR arthrography and SPECT/CT arthrography images was fully diagnostic in 23 of 28 wrists (82 %) and 25 of 28 wrists (89 %), respectively. SPECT/CT arthrography was not diagnostic for ligament lesions due to insufficient intraarticular contrast in one wrist. MR and SPECT/CT images showed concordant findings regarding TFCC lesions in 22 of 27 wrists (81 %), SL ligament in 22 of 27 wrists (81 %) and LT ligament in 23 of 27 wrists (85 %). Bone marrow oedema on MR images and scintigraphic uptake were concordant in 21 of 28 wrists (75 %). MR images showed partial TFCC defects in four patients with normal SPECT/CT images. MR images showed bone marrow oedema in 4 of 28 wrists (14 %) without scintigraphic uptake, and scintigraphic uptake was present without MR bone marrow oedema in three wrists (11 %). Regarding diagnosis of ulnar impaction the concordance rate between CT and SPECT/CT was 100 % and reached 96 % (27 of 28) between MR and SPECT/CT arthrography. The sensitivity and specificity of MR, CT and SPECT/CT arthrography were 93 %, 100 % and 100 %, and 93 %, 93 % and 93

Sedation of children for MR or CT imaging examination using chloral hydrate

International Nuclear Information System (INIS)

Song, Jong Gi; Kim, Woo Sun; Kim, In One; Yeon, Kyung Mo; Han, Man Chung

1994-01-01

Pediatric sedation is an important factor for obtaining the images of good quality. We performed this study to analyze the efficacy of our sedation protocol using chloral hydrate. We collected prospectively 151 sedation records of children(1 day-15 years old), who were sedated with chloral hydrate for MR(n=112) or CT(n=39) studies. We initially administered 50 mg/Kg orally(n=94) or rectally(n=57) 30 minutes before the scheduled examinations, and then administered additional dose (second dose: 25-35 mg/Kg, third dose: 10-15 mg/Kg) to patients whom initial dose failed to sedate. Satisfactory sedation was achieved by initial administration in 109 patients(72%) without significant difference between oral(per oral; P. O.) and rectal(per rectal: P.R.) administration. Second dose was required in 28% and third dose in 5%. MR and CT examinations required second dose in 36(32%) and 6 patients(15%), respectively. P.O. -patients vomited in 5%. P.R. -patients defecated in 22% after initial administration. There were no other serious complications. Time interval from the drug administration to the start of examinations was 33 minutes in initial-dose-group and 64 minutes in additional-dose-group. Two patients could not complete MR examination due to early arousal. Prolonged sedation, requiring more than 30 minutes for alertness after MR and CT examinations, was encountered in twenty(18%) and two patients(5%) respectively. Our protocol using chloral hydrate(P.O. or P.R.) is thought to be an effective and safe method for pediatric sedation for MR or CT imaging

Central nervous system involvement of leukemia and systemic lymphoma in children. CT and MR findings

International Nuclear Information System (INIS)

Tomura, Noriaki; Hirano, Hiroko; Kato, Kohki; Sashi, Ryuji; Hashimoto, Manabu; Watarai, Jiro; Watanabe, Arata

1997-01-01

The purpose of this paper is to retrospectively evaluate CT and MR findings of central nervous system (CNS) involvement of leukemia and systemic lymphoma in children. Over a 12-year period, sixty-five patients with leukemia and fifteen patients with systemic lymphoma underwent cerebral CT and/or MR imaging. Nine patients were diagnosed as CNS involvement of leukemia and lymphoma. The CT and MR abnormalities in these patients were correlated with the findings of histology, cerebrospinal fluid cytology, and/or treatment. The age of the patients ranged from 0 to 15 years old. They consisted of 6 boys and 3 girls. The CT examinations were performed before and after contrast administration. MR examinations were performed on a 1.5-T unit, and T1-weighted, T2-weighted, and proton density-weighted images were obtained using spin-echo or fast spin-echo sequences. Tumor masses were present in seven with leukemia, and in two with malignant lymphoma. On the CT scan, tumor masses were hyperdense with contrast enhancement. On the MR images, their signals were variable. In all of nine patients, tumor masses were contiguous with a meningeal surface. Postcontrast T1-weighted images were valuable in demonstrating meningeal infiltration. Tumoral hemorrhage was found in two patients. In a patient with tumor at the superior sagittal sinus, venous infarct was observed. CNS leukemic and lymphomatous masses are almost hyperdense on the CT and they are characteristically contiguous with a meningeal surface. MR imaging was valuable in demonstrating meningeal infiltration. (K.H.)

CT-guided puncture for direct MR-arthrography of the shoulder: Description of possible techniques

Directory of Open Access Journals (Sweden)

Hauth E

2016-07-01

Full Text Available The following report describes the possible techniques of CT-guided puncture for direct magnetic resonance (MR arthrography of the shoulder. CT-guided puncture can be regarded as an alternative technique to fluoroscopic- or ultrasound-guided puncture for MR-arthrography of the shoulder with high efficiency, low dose and extremely low complication rate.

The US, CT and MR findings of cubital bursitis: a report of five cases

International Nuclear Information System (INIS)

Liessi, G.; Cesari, S.; Spaliviero, B.; Dell'Antonio, C.; Avventi, P.

1996-01-01

Objective. The purpose of the study was to evaluate the appearance of ''cubital bursitis'' on ultrasonography and CT and MR imaging. ''Cubital bursitis'' is a rare pathological condition involving a large swelling of the bicipito-radial or interosseous bursae located at the insertion of the distal biceps tendon on the radial tuberosity. Design and patients. We report on five patients with ''cubital bursitis'' resulting from their work or sporting activities. All patients underwent an ultrasound and MR examination. CT scans were performed on two patients before and after contrast enhancement. Results. Ultrasound studies showed a fusiform anechoic or hypoechoic lesion. CT images showed the lesions but there were some difficulties in determining the exact extent of the bursae. MR imaging showed the enlarged bursae and their fluid content. Four patients each underwent a surgical procedure. Conclusion. Ultrasound and CT were effective in the evaluation of ''cubital bursitis'', but with some diagnostic difficulties. MR imaging is probably the method of choice for determining both the development of the bursae and their fluid content. (orig.)

The US, CT and MR findings of cubital bursitis: a report of five cases

Energy Technology Data Exchange (ETDEWEB)

Liessi, G. [Servizio di Radiologia, Ospedale, I-31033 Castelfranco V.to, Ulss 8 (Tuvalu) (Italy); Cesari, S. [Servizio di Radiologia, Ospedale, I-31033 Castelfranco V.to, Ulss 8 (Tuvalu) (Italy); Spaliviero, B. [Servizio di Radiologia, Ospedale, I-31033 Castelfranco V.to, Ulss 8 (Tuvalu) (Italy); Dell`Antonio, C. [Servizio di Radiologia, Ospedale, I-31033 Castelfranco V.to, Ulss 8 (Tuvalu) (Italy); Avventi, P. [Servizio di Radiologia, Ospedale, I-31033 Castelfranco V.to, Ulss 8 (Tuvalu) (Italy)

1996-07-01

Objective. The purpose of the study was to evaluate the appearance of ``cubital bursitis`` on ultrasonography and CT and MR imaging. ``Cubital bursitis`` is a rare pathological condition involving a large swelling of the bicipito-radial or interosseous bursae located at the insertion of the distal biceps tendon on the radial tuberosity. Design and patients. We report on five patients with ``cubital bursitis`` resulting from their work or sporting activities. All patients underwent an ultrasound and MR examination. CT scans were performed on two patients before and after contrast enhancement. Results. Ultrasound studies showed a fusiform anechoic or hypoechoic lesion. CT images showed the lesions but there were some difficulties in determining the exact extent of the bursae. MR imaging showed the enlarged bursae and their fluid content. Four patients each underwent a surgical procedure. Conclusion. Ultrasound and CT were effective in the evaluation of ``cubital bursitis``, but with some diagnostic difficulties. MR imaging is probably the method of choice for determining both the development of the bursae and their fluid content. (orig.)

Muscular involvement by malignant lymphoma: CT and MR findings

International Nuclear Information System (INIS)

Kim, Baek Hyun

2000-01-01

To investigate the CT and MR findings of muscular involvement by malignant lymphoma. Thirteen patients with biopsy-proved muscular involvement by malignant lymphoma were included in this study. Two patients were primary muscle lymphoma and 11 patients were muscle lymphoma by secondary involvement of malignant lymphoma. CT of 10 patients (6 pre-contrast CT and 9 postcontrast CT) and MRI of 6 patients (all with pre a nd post-contrast studies) were retrospectively analyzed. In the majority of patients (84.6%, 11/13), the appearance of muscular involvement was the diffuse enlargement of several muscles as like as a group. The muscles involved by malignant lymphoma showed iso-attenuation (5/6) and homogeneity (6/6) on pre-contrast CT scan, and high attenuation (5/9) or iso-attenuation (4/9) and homogeneity (7/9) on post-contrast CT scan. The signal intensity of involved muscle showed slightly hyper- (4/6) or iso-intense (2/6) and homogeneous (6/6) on T1-weighted images, and hyper-intense (6/6) and homogeneous (4/6) on T2- and Gadolinium-enhanced T1-weighted images. Adjacent bone change was demonstrated in 69.2% (9/13), subcutaneous fat change in 61.5% (8/13), and neurovascular encasement within involved muscle in 53.8% (7/13). The CT and MR findings of muscular involvement by malignant lymphoma were diffuse enlargement of several muscles with homogeneous attenuation or signal intensity, and frequent changes in adjacent bones and subcutaneous fat, or neurovascular encasement. (author)

Intra-articular gouty tophi of the knee: CT and MR imaging in 12 patients

International Nuclear Information System (INIS)

Chen, C.K.H.; Yeh Lee Ren; Pan Huay-Ben; Yang Chien-Fang; National Yang-Ming Univ., Taipei; Lu Yih-Chau; Wang Jyh-Seng; Resnick, D.; California Univ., Los Angeles, CA

1999-01-01

Objective. To define the imaging characteristics of intra-articular tophi of the knee. Design and patients. Twelve patients with intra-articular tophi in the knee were studied with routine MR imaging, gadolinium (Gd)-enhanced MR imaging, and CT over a 4-year period. There were 11 men and one woman, 25-82 years of age (mean age 48 years). Four patients did not have a documented history of gout at the time of the MR examination. The diagnosis of intra-articular tophi was provided by arthroscopy and histological examination (5 patients), by microscopic study of joint fluid (5 patients), or by characteristic clinical, laboratory and imaging findings (2 patients). Results. In 15 MR examinations the tophi were located purely intra-articularly in 10 knees. In the remaining five MR studies, periarticular soft tissues or bone, or both, were involved. All the intra-articular tophi manifested low to intermediate signal intensity on both T1- and T2-weighted images. All five Gd-enhanced MR examinations demonstrated a heterogeneous peripheral enhancement. All 10 CT scans showed varying degrees of stippled calcifications within the tophi. The nature of the calcifications was confirmed on histological examination in three patients. Conclusion. Presenting clinical manifestations of gout may relate to intra-articular tophaceous deposits. Such deposits present as masses on MR images with low to intermediate signal intensity on both T1- and T2-weighted images and a characteristic enhancement pattern following intravenous Gd administration. These features relate primarily to internal calcifications, which are most evident on CT images. MR evaluation (including Gd administration) supplemented, in some cases, with CT scanning allows accurate diagnosis of intra-articular tophaceous deposits. (orig.)

CT-MR image data fusion for computer assisted navigated neurosurgery of temporal bone tumors

International Nuclear Information System (INIS)

Nemec, Stefan Franz; Donat, Markus Alexander; Mehrain, Sheida; Friedrich, Klaus; Krestan, Christian; Matula, Christian; Imhof, Herwig; Czerny, Christian

2007-01-01

Purpose: To demonstrate the value of multi detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative work up of temporal bone tumors and to present, especially, CT and MR image fusion for surgical planning and performance in computer assisted navigated neurosurgery of temporal bone tumors. Materials and methods: Fifteen patients with temporal bone tumors underwent MDCT and MRI. MDCT was performed in high-resolution bone window level setting in axial plane. The reconstructed MDCT slice thickness was 0.8 mm. MRI was performed in axial and coronal plane with T2-weighted fast spin-echo (FSE) sequences, un-enhanced and contrast-enhanced T1-weighted spin-echo (SE) sequences, and coronal T1-weighted SE sequences with fat suppression and with 3D T1-weighted gradient-echo (GE) contrast-enhanced sequences in axial plane. The 3D T1-weighted GE sequence had a slice thickness of 1 mm. Image data sets of CT and 3D T1-weighted GE sequences were merged utilizing a workstation to create CT-MR fusion images. MDCT and MR images were separately used to depict and characterize lesions. The fusion images were utilized for interventional planning and intraoperative image guidance. The intraoperative accuracy of the navigation unit was measured, defined as the deviation between the same landmark in the navigation image and the patient. Results: Tumorous lesions of bone and soft tissue were well delineated and characterized by CT and MR images. The images played a crucial role in the differentiation of benign and malignant pathologies, which consisted of 13 benign and 2 malignant tumors. The CT-MR fusion images supported the surgeon in preoperative planning and improved surgical performance. The mean intraoperative accuracy of the navigation system was 1.25 mm. Conclusion: CT and MRI are essential in the preoperative work up of temporal bone tumors. CT-MR image data fusion presents an accurate tool for planning the correct surgical procedure and is a

Modern diagnostics of cystic liver lesions and hemangiomas; Moderne Diagnostik zystischer Leberlaesionen und Haemangiome

Energy Technology Data Exchange (ETDEWEB)

Poetter-Lang, S.; Bastati-Huber, N.; Ba-Ssalamah, A. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Wien (Austria); Brancatelli, G. [Universitaetsklinikum Palermo, Abteilung Radiologie, Palermo (Italy)

2015-01-01

Cystic liver lesions incorporate a broad heterogeneous group of mostly benign but also malignant abnormalities. The radiological aim is the non-invasive diagnosis with the use of different imaging modalities to determine the type of lesion. The common generally asymptomatic incidental findings of cystic lesions on ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) must be classified on the basis of specific imaging features. Such a differentiation is essential because the clinical consequences and the appropriate therapy can vary depending on the underlying pathology. Due to the morphological overlap of many cystic lesions, conventional radiological methods are often insufficient. The huge advances in cross-sectional imaging (multidetector CT, MRI with special sequences and different contrast agents and MR cholangiopancreatography) in combination with the clinical history usually enable a non-invasive diagnosis. Pathognomonic morphological and hemodynamic lesion features, as well as a knowledge of the pathomechanisms, help to differentiate this broad spectrum of entities. In this article the different entities of cystic liver lesions, together with the appropriate diagnostic method for detection and distinction and including their strengths and limitations, are demonstrated. A well-founded knowledge about the development of various cystic liver lesions and the suitable choice of imaging method facilitate a non-invasive diagnosis. (orig.) [German] Die zystischen Leberlaesionen umfassen eine grosse heterogene Gruppe meist benigner, jedoch auch maligner Veraenderungen. Das radiologische Ziel ist die nichtinvasive Artdiagnose mithilfe verschiedener bildgebender Verfahren. Die haeufigen, meist asymptomatischen Zufallsbefunde in Ultraschall, CT und MRT muessen anhand spezieller bildgebender Kriterien klassifiziert werden. Eine Differenzierung ist hierbei essenziell, da die klinischen Konsequenzen und weiterfuehrenden Therapien je nach zugrunde

Secondary necrosis: the radiosurgery in the cerebral arteriovenous malformations. CT and MR aspects

International Nuclear Information System (INIS)

Pina, J.I.; Medrano, J.; Benito, J.L. de; Sierra, R. la; Feijoo, R.; Villavieja, J.L.

1995-01-01

The Ct and MR findings are presented for two patients previously diagnosed as having cerebral arteriovenous malformations (AVM), treated by means of stereotaxic radiosurgery. The study of their course following corticosteroid therapy is also reported. The diagnosis was based on changes in the MR signal and density on CT and on their late onset, and was confirmed by puncture. The good clinical and radiological course is discussed. (Author) 10 refs

CNS involvement in AIDS: spectrum of CT and MR findings

International Nuclear Information System (INIS)

Thurnher, M.M.; Thurnher, S.A.; Schindler, E.

1997-01-01

The brain may be affected by a variety of abnormalities in association with human immunodeficiency virus (HIV) infection. Knowledge of their existence and characteristic imaging features are important to radiologists for detection, diagnosis, and initiation of an appropriate treatment. Although there is a considerable overlap in the imaging characteristics of different entities, some findings are found to be very suggestive of a particular disease. The CT and MR imaging techniques are commonly used in the diagnosis of neurological disorders in acquired immunodeficiency syndrome (AIDS) patients, to verify treatment response and to guide brain biopsy. This review attempts to describe CT and MR features of infectious and malignant brain disorders in HIV-seropositive patients. (orig.). With 13 figs

Disease progression in AIDS on PET fluorodeoxyglucose, CT and MR brain images

International Nuclear Information System (INIS)

Verma, R.C.; Bennett, L.; Gan, M.; Kloumehr, F.; Mathisen, G.; Jones, F.D.; Wasterlain, C.; Mandelkern, M.; Ropchan, J.; Blahd, W.; Yaghmal, I.

1990-01-01

This paper correlates changes in the brain demonstrated on F-18 fluorodeoxyglucose (FDG) positron emission tomographic (PET) scans and CT or MR images with disease severity in patients with acquired immunodeficiency syndrome (AIDS). Data from 30 patients who tested positive for human immunodeficiency virus (HIV) who were at various stages of AIDS, and who had undergone FDG PET, CT, and/or MR imaging were reviewed retrospectively. The average CD4 lymphocyte counts, an indicator of disease severity in AIDS, in 25 symptomatic (group I) and five healthy seropositive (group II) subjects were 300 and 694 cells/mm 3 , respectively. Cortical atrophy was present on CT and/or MR imaging in 92% in group I and only 20% in group II. Of the 17 patients in group I who underwent PET scans 11 demonstrated an elevated basal ganglia to frontal cortex (BG/FC) ratio of FDG uptake; only one of the four in group II had this finding

Chondroitin sulfate iron colloid-enhanced MR imaging in patients with hepatocellular carcinoma. Comparison with CT during arterial portography

Energy Technology Data Exchange (ETDEWEB)

Kamba, Masayuki [Dept. of Radiology, Tottori Univ., Yonago (Japan); Suto, Y. [Dept. of Radiology, Tottori Univ., Yonago (Japan); Kato, T. [Dept. of Radiology, Tottori Univ., Yonago (Japan)

1994-11-01

Chondroitin sulfate iron colloid (CSIC) was used as an MR contrast agent for the detection of hepatocellular carcinoma (HCC). The findings of 25 surgically confirmed HCCs in 19 patients were retrospectively analyzed. T1-, T2- and proton density-weighted spin echo MR images were obtained before and after i.v. injection of 23.6 {mu}M Fe/kg of CSIC. Unenhanced and CSIC-enhanced MR images and images obtained by CT during arterial protography (CT-AP) were correlated with surgical pathology findings. The sensitivities of CSIC-enhanced and unenhanced MR imaging, and CT-AP were 92%, 80%, and 88%, respectively. No significant differences were noted. Portal flow abnormalities demonstrated by CT-AP did not affect the detection of HCC by CSIC-enhanced MR imaging. CSIC-enhancement at MR imaging was a disadvantage in the detection of lesions less than 1 cm in diameter. CSIC-enhanced MR imaging is a supplemental method for the detection of HCC. (orig.).

Primary staging of laryngeal and hypopharyngeal cancer: CT, MR imaging and dual-energy CT

International Nuclear Information System (INIS)

Kuno, Hirofumi; Onaya, Hiroaki; Fujii, Satoshi; Ojiri, Hiroya; Otani, Katharina; Satake, Mitsuo

2014-01-01

Laryngeal and hypopharyngeal cancer, in particular T4a disease associated with cartilage invasion and extralaryngeal spread, needs to be evaluated accurately because treatment can impact heavily on a patient's quality of life. Reliable imaging tools are therefore indispensible. CT offers high spatial and temporal resolution and remains the preferred imaging modality. Although cartilage invasion can be diagnosed with acceptable accuracy by applying defined criteria for combinations of erosion, lysis and transmural extralaryngeal spread, iodine-enhanced tumors and non-ossified cartilage are sometimes difficult to distinguish. MR offers high contrast resolution for images without motion artifacts, although inflammatory changes in cartilage sometimes resemble cartilage invasion. With dual-energy CT, combined iodine overlay images and weighted average images can be used for evaluation of cartilage invasion, since iodine enhancement is evident in tumor tissue but not in cartilage. Extralaryngeal spread can be evaluated from CT, MR or dual-energy CT images and the routes of tumor spread into the extralaryngeal soft tissue must be considered; (1) via the thyrohyoid membrane along the superior laryngeal neurovascular bundle, (2) via the inferior pharyngeal constrictor muscle, and (3) via the cricothyroid membrane. Radiologists need to understand the advantages and limitations of each imaging modality for staging of laryngeal and hypopharyngeal cancer

CT and MR findings of primitive neuroectodermal tumor

International Nuclear Information System (INIS)

Kook, Shin Ho; Kim, In One; Chang, Kee Hyun; Han, Moon Hee; Cho, Byung Kyu

1991-01-01

Cerebral primitive neuroectodermal tumor (PNET), consisting of undifferentiated primitive cells, is a neoplasm of children and young adults that occurs predominantly in the supratentorial compartment. In this report, we retrospectively reviewed and analyzed 18 CT and 6 MR findings in 18 patients with pathologically-proven PNET to discover the characteristic findings, if may. The most characteristic feature of the PNETs was a well-defined multilobular oval or round large mass with components of peripheral cystic change or calcification in the cerebral hemisphere, especially in the parietal lobe. Usually there was only minimal surrounding edema. The CT density of the tumor was iso - or slightly high density with homogeneous contrast enhancement in the solid portion and low density in the cystic area. MR findings demonstrated iso - signal intensity on both T1 - weighted (T1WI) and T2-weighted (T2WI) images and dense enhancement in the solid element. The cystic portion revealed low intensity on T1WI and high intensity on T2WI

Robust inverse-consistent affine CT-MR registration in MRI-assisted and MRI-alone prostate radiation therapy.

Science.gov (United States)

Rivest-Hénault, David; Dowson, Nicholas; Greer, Peter B; Fripp, Jurgen; Dowling, Jason A

2015-07-01

CT-MR registration is a critical component of many radiation oncology protocols. In prostate external beam radiation therapy, it allows the propagation of MR-derived contours to reference CT images at the planning stage, and it enables dose mapping during dosimetry studies. The use of carefully registered CT-MR atlases allows the estimation of patient specific electron density maps from MRI scans, enabling MRI-alone radiation therapy planning and treatment adaptation. In all cases, the precision and accuracy achieved by registration influences the quality of the entire process. Most current registration algorithms do not robustly generalize and lack inverse-consistency, increasing the risk of human error and acting as a source of bias in studies where information is propagated in a particular direction, e.g. CT to MR or vice versa. In MRI-based treatment planning where both CT and MR scans serve as spatial references, inverse-consistency is critical, if under-acknowledged. A robust, inverse-consistent, rigid/affine registration algorithm that is well suited to CT-MR alignment in prostate radiation therapy is presented. The presented method is based on a robust block-matching optimization process that utilises a half-way space definition to maintain inverse-consistency. Inverse-consistency substantially reduces the influence of the order of input images, simplifying analysis, and increasing robustness. An open source implementation is available online at http://aehrc.github.io/Mirorr/. Experimental results on a challenging 35 CT-MR pelvis dataset demonstrate that the proposed method is more accurate than other popular registration packages and is at least as accurate as the state of the art, while being more robust and having an order of magnitude higher inverse-consistency than competing approaches. The presented results demonstrate that the proposed registration algorithm is readily applicable to prostate radiation therapy planning. Copyright © 2015. Published by

Thoracic staging in lung cancer: prospective comparison of 18F-FDG PET/MR imaging and 18F-FDG PET/CT.

Science.gov (United States)

Heusch, Philipp; Buchbender, Christian; Köhler, Jens; Nensa, Felix; Gauler, Thomas; Gomez, Benedikt; Reis, Henning; Stamatis, Georgios; Kühl, Hilmar; Hartung, Verena; Heusner, Till A

2014-03-01

Therapeutic decisions in non-small cell lung cancer (NSCLC) patients depend on the tumor stage. PET/CT with (18)F-FDG is widely accepted as the diagnostic standard of care. The purpose of this study was to compare a dedicated pulmonary (18)F-FDG PET/MR imaging protocol with (18)F-FDG PET/CT for primary and locoregional lymph node staging in NSCLC patients using histopathology as the reference. Twenty-two patients (12 men, 10 women; mean age ± SD, 65.1 ± 9.1 y) with histopathologically confirmed NSCLC underwent (18)F-FDG PET/CT, followed by (18)F-FDG PET/MR imaging, including a dedicated pulmonary MR imaging protocol. T and N staging according to the seventh edition of the American Joint Committee on Cancer staging manual was performed by 2 readers in separate sessions for (18)F-FDG PET/CT and PET/MR imaging, respectively. Results from histopathology were used as the standard of reference. The mean and maximum standardized uptake value (SUV(mean) and SUV(max), respectively) and maximum diameter of the primary tumor was measured and compared in (18)F-FDG PET/CT and PET/MR imaging. PET/MR imaging and (18)F-FDG PET/CT agreed on T stages in 16 of 16 of patients (100%). All patients were correctly staged by (18)F-FDG PET/CT and PET/MR (100%), compared with histopathology. There was no statistically significant difference between (18)F-FDG PET/CT and (18)F-FDG PET/MR imaging for lymph node metastases detection (P = 0.48). For definition of thoracic N stages, PET/MR imaging and (18)F-FDG PET/CT were concordant in 20 of 22 patients (91%). PET/MR imaging determined the N stage correctly in 20 of 22 patients (91%). (18)F-FDG PET/CT determined the N stage correctly in 18 of 22 patients (82%). The mean differences for SUV(mean) and SUV(max) of NSCLC in (18)F-FDG PET/MR imaging and (18)F-FDG PET/CT were 0.21 and -5.06. These differences were not statistically significant (P > 0.05). The SUV(mean) and SUV(max) measurements derived from (18)F-FDG PET/CT and (18)F-FDG PET/MR

Value of ultrasonography, Ct and MR imaging in the diagnosis of primary hyperparathyroidism

International Nuclear Information System (INIS)

Tziakouri, C.; Eracleous, E.; Skannavis, S.; Pierides, A.; Symeonides, P.; Gourtsoyiannis, N.

1996-01-01

Purpose: To evaluate the significance of preoperative localization of abnormal parathyroid glands to the surgical outcome in patients with primary hyperparathyroidism. Material and Methods: Thirty-nine patients with primary hyperparathyroidism were studied preoperatively with US (39 patients), CT (30 patients) and MR imaging (18 patients). The overall diagnostic accuracy for US was 87%, CT 66% and MR 94%. In patients with a single parathyroid adenoma US was the most cost-effective localization technique with a detection rate of 96%. CT had a lower detection rate (78%) but was of particular value for fairly large ectopic adenomas in the root of the neck. MR imaging was a good confirmatory test (93%). In patients with multiple gland disease (primary hyperplasia and multiple adenomas), no single localization study alone was sufficient. Combination of all 3 studies, however, alerted the physician to the presence of disease in more than one gland in 87% of these patients. Conclusion: US, CT and MR imaging followed by surgery performed by an experienced surgeon provided good clinical results in 39 patients with primary hyperparathyroidism. Preoperative localization was especially useful in patients with primary parathyroid hyperplasia or multiple adenomas and in patients with ectopic parathyroid adenomas in the root of the neck. We recommend identification of all abnormal parathyroid glands prior to surgery. (orig.)

Nasal Chondromesenchymal Hamartoma: CT and MR Imaging Findings

International Nuclear Information System (INIS)

Kim, Ji Eun; Kim, Hyung Jin; Kim, Ji Hye; Ko, Young Hyeh; Chung, Seung Kyu

2009-01-01

We report CT and MR imaging findings for a case of nasal chondromesenchymal hamartoma occurring in a 19-month-old boy. A nasal chondromesenchymal hamartoma is a rare benign pediatric hamartoma that can simulate malignancy. Although rare, knowledge of this entity is essential to avoid potentially harmful therapies

CT- and MR-guided interventions in radiology. 2. ed.

International Nuclear Information System (INIS)

Mahnken, Andreas H.; Wilhelm, Kai E.; Ricke, Jens

2013-01-01

Revised and extended second edition that covers a broad range of non-vascular interventions guided by CT or MR imaging. Discusses in detail indications, materials, techniques, and results. Includes a comprehensive section on interventional oncology. Richly illustrated source of information and guidance for all radiologists who deal with non-vascular procedures. Interventional radiology is an indispensable and still expanding area of modern medicine that encompasses numerous diagnostic and therapeutic procedures. Cross-sectional imaging modalities such as computed tomography (CT) and magnetic resonance (MR) have emerged as important techniques for non-vascular interventions, including percutaneous biopsy, drainage, ablation, and neurolysis. Various organs, diseases, and lesions can be approached in this way, permitting the treatment and management of tumors, fluid collections, and pain, the embolization of endoleaks, the provision of access to hollow organs, etc. Accordingly, interventional radiology is now an integral component of the interdisciplinary management of numerous disorders. The revised and significantly extended second edition of this volume covers a broad range of non-vascular interventions guided by CT or MR imaging. Indications, materials, techniques, and results are all carefully discussed. A particularly comprehensive section is devoted to interventional oncology as the most rapidly growing branch of interventional radiology. In addition, detailed information is provided that will assist in establishing and developing an interventional service. This richly illustrated book will be a most valuable source of information and guidance for all radiologists who deal with non-vascular procedures.

CT and MR Imagings of Semicircular Canal Aplasia

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Shin, Chung Hee; Hong, Hyun Sook; Yi, Beom Ha; Cha, Jang Gyu; Park, Seong Jin; Kim, Dae Ho; Lee, Hae Kyung; Kim, Shi Chan [Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of)

2009-07-15

To evaluate the clinical, CT and MR imaging findings of semicircular canal (SCC) aplasia and to evaluate if a correlation exists between these findings and the associated anomalies or syndromes. This study retrospectively reviewed the CT and MRI findings of five patients with SCC aplasia. The CT and MR findings were analyzed for SCC, direction of facial nerve canal, cochlea, vestibule, oval or round window, middle ear ossicles, and internal auditory canal (IAC). The subjects included three boys and two girls ranging in age from one to 120 months (mean age; 51 months). Four of the subjects had the CHARGE syndrome, and one had the Goldenhar syndrome. Moreover, four subjects had sensorineural hearing loss and one had combined hearing loss. The course of the facial nerve canal was abnormal in all five cases. Moreover, trapped cochlea and dysplastic modiolus were each observed in one case. Four subjects had atresia of the oval window; whereas ankylosis of the ossicles was present in three subjects. IAC stenosis was present in one patient with the CHARGE syndrome. The aberrant course of the facial nerve canal, atresia of the oval window, and abnormal ossicles were frequently associated in patients with SCC aplasia. In addition, the Goldenhar and CHARGE syndromes were also commonly associated syndromes.

Systematisation of spatial uncertainties for comparison between a MR and a CT-based radiotherapy workflow for prostate treatments

International Nuclear Information System (INIS)

Nyholm, Tufve; Nyberg, Morgan; Karlsson, Magnus G; Karlsson, Mikael

2009-01-01

In the present work we compared the spatial uncertainties associated with a MR-based workflow for external radiotherapy of prostate cancer to a standard CT-based workflow. The MR-based workflow relies on target definition and patient positioning based on MR imaging. A solution for patient transport between the MR scanner and the treatment units has been developed. For the CT-based workflow, the target is defined on a MR series but then transferred to a CT study through image registration before treatment planning, and a patient positioning using portal imaging and fiducial markers. An 'open bore' 1.5T MRI scanner, Siemens Espree, has been installed in the radiotherapy department in near proximity to a treatment unit to enable patient transport between the two installations, and hence use the MRI for patient positioning. The spatial uncertainty caused by the transport was added to the uncertainty originating from the target definition process, estimated through a review of the scientific literature. The uncertainty in the CT-based workflow was estimated through a literature review. The systematic uncertainties, affecting all treatment fractions, are reduced from 3-4 mm (1Sd) with a CT based workflow to 2-3 mm with a MR based workflow. The main contributing factor to this improvement is the exclusion of registration between MR and CT in the planning phase of the treatment. Treatment planning directly on MR images reduce the spatial uncertainty for prostate treatments

CT and MR imaging of closed head trauma

International Nuclear Information System (INIS)

Park, Byung Moon; Kim, Wan Jin; Kim, Dae Ho; Lee, Hae Kyung; Chung, Moo Chan; Kwon, Kui Hyang; Kim, Ki Jeong

1990-01-01

The distribution and extent of traumatic lesions were evaluated with MR imaging in 40 patients with closed head injuries. The primary intraaxial lesions were classified into four main types, according to their topographical distribution within the brain ; cortical contusion (54%), diffuse axonal injury (35%), subcortical gray matter injury (4%), primary brain stem injury (7%). MR was found to be superior to CT and to be very useful in the detection of traumatic head lesions and T2WI were most useful for lesion detection. But T1WI proved to be also useful for detection of hemorrhage and anatomical localization

MR appearance of cartilage defects of the knee: preliminary results of a spiral CT arthrography-guided analysis

International Nuclear Information System (INIS)

Berg, B.C. vande; Lecouvet, F.E.; Maldague, B.; Malghem, J.

2004-01-01

The aim of this study was to determine signal intensity patterns of cartilage defects at MR imaging. The MR imaging (3-mm-thick fat-suppressed intermediate-weighted fast spin-echo images) was obtained in 31 knees (21 male and 10 female patients; mean age 45.5 years) blindly selected from a series of 252 consecutive knees investigated by dual-detector spiral CT arthrography. Two radiologists determined in consensus the MR signal intensity of the cartilage areas where cartilage defects had been demonstrated on the corresponding reformatted CT arthrographic images. There were 83 cartilage defects at spiral CT arthrography. In 52 (63%) lesion areas, the MR signal intensity was higher than that of adjacent normal cartilage with signal intensity equivalent to (n=31) or lower than (n=21) that of articular fluid. The MR signal intensity was equivalent to that of adjacent normal cartilage in 17 (20%) lesion areas and lower than that of adjacent cartilage in 8 (10%) lesion areas. In 6 (7%) lesion areas, mixed low and high signal intensity was observed. The MR signal intensity of cartilage defects demonstrated on spiral CT arthrographic images varies from low to high on fat-suppressed intermediate-weighted fast spin-echo MR images obtained with our equipment and MR parameters. (orig.)

CT and MR evaluation of migrational disorders of the brain. Pt. 2. Schizencephaly, heterotopia and polymicrogyria

Energy Technology Data Exchange (ETDEWEB)

Byrd, S E; Osborn, R E; Bohan, T P; Naidich, T P

1989-05-01

The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria - pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (Part II) deals with our patients with schizencephaly, heterotopia and polymicrogyria. These patients presented clinically with a variety of symptoms. The most common were seizures, delayed development, failure to thrive and hydrocephalus. CT and MR both demonstrated the characteristic findings in all of our patients except the polymicrogyria group. The gray matter and cleft abnormalities seen in these disorders were demonstrated with CT and MR. However, MR provided better delineation of these disorders than CT. Because some forms of migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling.

MR imaging characteristics of osteoradionecrosis of the pelvis after radiation therapy on gynecological tumors; Pelvine Osteoradionekrosen: Magnetresonanztomographische Charakteristika

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Schmitt, J.; Abolmaali, N.D.; Jacobi, V.; Vogl, T.J. [Institut fuer Diagnostische u. Interventionelle Radiologie, Klinikum der J. W. Goethe-Universitaet, Frankfurt (Germany); Hoeller, U. [Staedtisches Krankenhaus Neukoelln, Berlin (Germany). Abt. Strahlentherapie; Schiemann, M.; Obert, K. [Klinikum der J. W. Goethe-Universitaet, Frankfurt (Germany). Klinik fuer Strahlentherapie und Onkologie

2002-01-01

Purpose: To describe MR imaging characteristics of osteoradionecrosis (ORN) of the pelvis as a result of radiation therapy (RT) on gynecological tumors. Material and Methods: Radiography, computed tomography (CT) and magnetic resonance imaging (MRI) were performed on 9 women (mean age 67.5 years) with gynecological tumors to identify ORN. T{sub 1}- and T{sub 2}-weighted sequences and contrast-enhanced t{sub 1}-weighted sequences with and without fat saturation were used. The patients began developing pain after the completion of RT indicating a possible ORN a which time MRI was performed. MR images were correlated with the results of clinical examinations. Results: Depending on the time elapsed after RT, ORN presented with different signal intensities. The acquired images suggested that signal changes in T{sub 2}-weighted images as well as the different enhancement behaviour of ORN could be dependent on the time elapsed after RT. Visualisation of the affected regions was best achieved with fat-saturated T{sub 1}-weighted sequences. CT showed increased density in the affected regions corresponding to osteosclerosis. In all cases the sacroiliac joint was affected, some times bilateraly. Conclusion: MRI is helpful in detecting and characterizing ORN. Changes in signal intensity, based on histopathological tissue changes could make a chronological classification possible. (orig.) [German] Zielsetzung: Evaluation MR-tomographischer Charakteristika pelviner Osteoradionekrosen (ORN) bei Patientinnen nach Strahlentherapie gynaekologischer Tumoren. Material und Methode: 9 Patientinnen (mittleres Alter: 67,5 Jahre) mit gynaekologischen Tumoren und gesicherten ORN wurden mit der Magnetresonanztomographie (MRT) untersucht. Die MRT wurde beim Auftreten von Beschwerden nach unterschiedlichen Zeiten nach Bestrahlungsabschluss durchgefuehrt und mit den Ergebnissen der klinischen Diagnostik korreliert. Ergebnisse: ORN kamen fuer MR in Abhaengigkeit vom Abstand zum Bestrahlungsende

MR spectroscopy in dementia; MR-Spektroskopie bei Demenz

Energy Technology Data Exchange (ETDEWEB)

Hauser, T.; Gerigk, L.; Giesel, F.; Schuster, L.; Essig, M. [Deutsches Krebsforschungszentrum (DKFZ) Heidelberg, Abteilung E010, Radiologie, Heidelberg (Germany)

2010-09-15

With an increasingly aging population we are faced with the problem of an increasing number of dementia patients. In addition to clinical, neuropsychological and laboratory procedures, MRI plays an important role in the early diagnosis of dementia. In addition to various morphological changes functional changes can also help in the diagnosis and differential diagnosis of dementia. Overall the diagnosis of dementia can be improved by using parameters from MR spectroscopy. This article focuses on MR spectroscopic changes in the physiological aging process as well as on changes in mild cognitive impairment a precursor of Alzheimer's dementia, in Alzheimer's dementia, frontotemporal dementia, vascular dementia and Lewy body dementia. (orig.) [German] Angesichts einer immer aelter werdenden Bevoelkerung sind wir mit dem Problem einer zunehmenden Zahl an Demenzerkrankungen konfrontiert. Neben klinischen, neuropsychologischen und laborchemischen Verfahren spielt die MRT zur Fruehdiagnostik einer Demenz eine wichtige Rolle. Morphologische Veraenderungen wie auch verschiedene funktionelle Verfahren helfen bei der Diagnostik und Differenzialdiagnostik einer Demenz. Insgesamt kann mittels MR-spektroskopischer Parameter die Diagnostik einer Demenz verbessert werden. In diesem Artikel soll auf MR-spektroskopische Veraenderungen im Rahmen des physiologischen Alterungsprozesses eingegangen werden. Ferner werden speziell Veraenderungen bei leichter kognitiver Beeintraechtigung, einer Vorform der Alzheimer-Demenz, bei Alzheimer-, frontotemporaler, vaskulaerer und Lewy-Koerper-Demenz eroertert. (orig.)

Supratentorial primary intra-axial tumors in children. MR and CT evaluation

International Nuclear Information System (INIS)

Higano, S.; Takahashi, S.; Kurihara, N.; Singh, L.N.; Yamada, S.; Ishii, K.; Matsumoto, K.; Shirane, R.; Katakura, R.

1997-01-01

Purpose: To evaluate the MR and CT features of pediatric supratentorial intra-axial tumors with respect to different diagnosis and the role of each investigation modality. Material and Methods: MR and CT findings in 40 children with 12 types of pathologically proven histological tumors were reviewed. Results: The location of tumors might be one clue to differential diagnosis. In our material, cysts (60%), calcifications (45%), and intratumoral hemorrhages (27%) were found in the tumors. Characteristic features noted in some lesions included: peritumoral hemosiderin deposition in cavernous angiomas; intratumoral flow void in a choroid plexus carcinoma and in glioblastomas; and hemicerebral atrophy in germinomas. A comparison between malignant and benign tumors showed perifocal edema and a mass effect to be signifcantly more common in malignant lesions. Homogeneous enhancement suggested a benign tumor and an inhomogeneous pattern represented malignancy, while the lack of obvious enhancement did not always suggest benignity. Intratumoral calcium deposition was a not uncommon finding in malignant tumors. Conclusion: In most cases, the exact diagnosis should be made hy histological examination but it is important for treatment planning that the appropriate depiction of tumor extension and tissue characterization be made by MR and CT. (orig.)

MR imaging, CT and CEA scintigraphy in the diagnosis of local recurrence of rectal carcinoma

International Nuclear Information System (INIS)

Blomqvist, L.; Holm, T.; Goeranson, H.; Jacobsson, H.; Ohlsen, H.; Larsson, S.A.

1996-01-01

Purpose: To compare advanced imaging techniques in the diagnosis of recurrent rectal cancer. Material and Methods: Twenty-five consecutive patients with either suspected or verified recurrence were examined by CT (n=25), MR with phased-array capabilities (n=24) and CEA scintigraphy (n=16). Three experienced radiologists (who were blinded to results obtained at surgery and histopathology) independently evaluated the films, one observer for each modality. Results: The MR radiologist arrived at a correct diagnosis in 87.5% of the examinations, the CT radiologist in 76% and the CEA radiologist in 75%. The MR radiologist's results correlated more often with reported pathology than did those of the CT radiologist with regard to the relation of recurrent tumor to surrounding structures in the pelvis. Conclusion: MR imaging is the most effective of the 3 modalities in the diagnosis of recurrent rectal cancer. (orig.)

Comparison of the sensitivity and specificity of CT and MR imaging in the detection of cervical nodal tumor necrosis and extracapsular tumor spread

International Nuclear Information System (INIS)

Yousem, D.M.; Som, P.M.; Schjwaibold, F.; Hendrix, R.

1991-01-01

This paper evaluates if MR imaging can achieve the sensitivity and specificity of enhanced CT in detecting tumoral nodal necrosis (TNN) and extracapsular tumor spread (ETS). Enhanced CT scans and unenhanced and enhanced MR images were retrospectively and separately reviewed by a study-blinded radiologist. Fifty-eight lymph nodes were evaluated for TNN and ETS. Readings were given for CT, T1-weighted MR, T2-weighted MR, T1-weighted and T2-weighted MR, enhanced T1-weighted fat-suppressed MR, and T1-weighted, T2-weighted, and enhanced fat suppressed T1-weighted MR. Pathology proof was used to assess TNN; CT and used to assess ETS. Enhanced CT had the highest sensitivity for TNN. The sensitivity of unenhanced MR ranged from 33% to 50%; that of enhanced MR was 47%. All MR sequences and cT had specificities for TNN >92%. The highest accuracy of MR for TNN was the unenhanced T1-weighted and T2-weighted images alone; CT accuracy was 90%. MR sensitivity for ETS was maximal with T1-weighted images; all sequences had specificities >90%. Gadolinium-enhanced images did not improve accuracy in TNN or ETS

CT, MR, 18F-FDG PET/CT, and their combined use for the assessment of mandibular invasion by squamous cell carcinomas of the oral cavity

International Nuclear Information System (INIS)

Gu, Dong Hyeon; Yoon, Dae Young; Chang, Suk Ki; Lim, Kyoung Ja; Seo, Young Lan; Yun, Eun Joo; Choi, Chul Soon; Bae, Sang Hoon; Park, Hee Chan

2010-01-01

Background: A reliable assessment of mandibular invasion is crucial for treatment planning to obtain both radical tumor resection and good functional results. Purpose: To retrospectively compare the diagnostic value of three different imaging methods - computed tomography (CT), magnetic resonance (MR) imaging, 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT - and their combined use for detection of mandibular invasion by squamous cell carcinoma (SCC) of the oral cavity. Material and Methods: Forty-six patients (39 men and 7 women; mean age, 59.4 years) suspected of having mandibular invasion by SCC of the oral cavity underwent CT, MR, and PET/CT within 2 weeks before surgery. First, each study was reviewed separately for the presence of mandibular invasion by tumors. Then, the value of combined images was assessed based on a confidence rating score for each modality assigned by observers. These results were verified with histopathologic findings. Results: Histopathologic examination revealed mandibular invasion in 12 of 46 SCCs. The sensitivity, specificity, and accuracy were 41.7%, 100%, and 84.8% for CT; 58.3%, 97.1%, and 87.0% for MR; and 58.3%, 97.1%, and 87.0% for PET/CT, respectively. The comparison of these modalities showed no statistically significant difference among them (P > 0.05). The combination of CT, MR, and PET/CT improved sensitivity (83.3%), without loss of specificity (100%) and accuracy (95.7%), although the difference failed to reach statistical significance (P > 0.05). Conclusion: The combined analysis of CT, MR, and PET/CT can improve sensitivity in the detection of mandibular invasion by SCC of the oral cavity

CT and MR findings of primary hepatic leiomyosarcome : a case report

International Nuclear Information System (INIS)

Lee, Jeong Min; Kim, Chong Soo; Lee, Sang Yong; Chung, Gyung Ho; Cho, Baek Hwan; Lee, Dong Keun

1997-01-01

We describe the CT and MR findings of primary leiomyosarcoma of the liver and review the radiological findings of the previous reports of this disease. A 35-year-old woman presented with discomfort in the right upper quadrant of the abdomen. On contrast-enhanced CT, a well circumscribed and lobulated, homogeneously hypoattenuating solid mass with slight peripheral enhancement was identified in the caudate lobe of the liver. On spin-echo MR imaging, the tumor showed homogeneous bypointensity on T1-weighted images and hyperintensity on T2-weighted images. Contrast-enhanced T1-weighted imaging showed markedly heterogeneous enhancement throughout the mass. (author). 7 refs., 1 fig

MR-urography and CT-urography: principles, examination techniques, applications

International Nuclear Information System (INIS)

Nolte-Ernsting, C.; Adam, G.; Staatz, G.; Wildberger, J.

2003-01-01

MR-urography (MRU) and CT-urography (CTU) provide refined imaging of the upper urinary tract not achievable with conventional intravenous urography (IVU). The traditional MR-urographic technique utilizes unenhanced, heavily T 2 -weighted turbo spin-echo sequences for obtaining static fluid images of the urinary tract independent of the excretory renal function. T 2 -weighted MR-urograms have proved to be excellent in visualizing the dilated urinary tract, even in non-excreting kidneys. In contrast, T 1 -weighted MRU reflects the excretory renal function and displays the urine flow through the upper tract after renal excretion of an intravenously administered gadolinium chelate. The gadolinium-enhanced urine is visualized with fast T 1 -weighted 3D-gradient-echo sequences. The combination of gadolinium and low-dose furosemide (5-10 mg) is the key for achieving a uniform distribution of gadolinium in the collecting system and for avoiding susceptibility artifacts (T 2 *-effects) in the urine. T 1 -weighted excretory MRU provides impressive urograms of both non-dilated and obstructed collecting systems in patients with normal or moderately impaired renal function. Multislice-CT-urography (MS-CTU) is also an excretory urography like T 1 -weighted MRU. Furthermore, MS-CTU can be combined with low-dose furosemide for accelerated passage of excreted contrast material obviating the need for abdominal compression. CT-urography is limited by its radiation burden and the nephrotoxicity of radiographic contrast media. Combining MRU or MS-CTU with conventional MRI or CT offers several applications, e.g., diagnosis of intrinsic and extrinsic tumors. Meanwhile, MRU has replaced IVU in pediatric uroradiology and is also recommended for the assessment of renal transplants. MS-CTU may provide valuable information in chronic urolithiasis, especially if associated with a distorted urinary tract anatomy. Both MRU and MS-CTU will play an important role in modern uroradiology. (orig

Spontaneous vertebral dissection: Clinical, conventional angiographic, CT, and MR findings

Energy Technology Data Exchange (ETDEWEB)

Provenzale, J.M.; Morgenlander, J.C. [Duke Univ. Medical Center, Durham, NC (United States); Gress, D. [Univ. of California, San Francisco, CA (United States)

1996-03-01

The purpose of this study was to determine if typical clinical and neuroradiologic patterns exist in patients with spontaneous vertebral artery (VA) dissection. The medical records and neuroradiologic examinations of 14 patients with spontaneous VA dissection were reviewed. The medical records were examined to exclude patients with a history of trauma and to record evidence of a nontratimatic precipitating event ({open_quotes}trivial trauma{close_quotes}) and presence of possible risk factors such as hypertension. All patients under-went conventional angiography, 13 either CT or MRI (II both CT and MRI), and 3 MRA. Conventional arteriograrris were evaluated for dissection site, evidence of fibromuscular dysplasia, luminal stenosis or occlusion, and pseudoaneurysm formation, CT examinations for the presence of infarction or subarachnoid hemorrhage, MR examinations for the presence of infarction or arterial signal abnormality, and MR angiograms for abnormality of the arterial signal column. Seven patients had precipitating events within 24 h of onset of symptoms that may have been causative of dissection and five had hypertension. At catheter angiography, two patients had dissections in two arteries (both VAs in one patient, VA and internal carotid artery in one patient), giving a total of 15 VAs with dissection. Dissection sites included V1 in four patients, V2 in one patient, V3 in three patients, V4 in six patients, and both V3 and V4 in one patient. Luminal stenosis was present in 13 VAs, occlusion in 2, pseudoaneurysm in 1, and evidence of fibromuscular dysplasia in 1. Posterior circulation infarcts were found on CT or MR in five patients. Subarachnoid hemorrhage was found on CT in two patients and by lumbar puncture alone in two patients. Abnormal periarterial signal on MRI was seen in three patients. MRA demonstrated absent VA signal in one patient, pseudoaneurysm in one, and a false-negative examination in one.

CT, MR and angiographic findings of hemangiopericytomas

International Nuclear Information System (INIS)

Lim, Soo Mee; Lee, Ho Kyu; Shin, Ji Hoon; Kim, Jae Kyun; Kim, Dae Hong; Choi, Choong Gon; Suh, Dae Chul

1999-01-01

Hemangiopericytoma(HP) exhibits its pathologic findings different from those of meningioma or other angiomatous tumor; and its clinical behavior is unique and prognosis worse than other cases. We reviewed the CT, MR and angiographic findings of HPs and evaluated differential radiologic points of comparison between typical meningiomas and meningeal HPs. MR(n=16), CT(n=5) and angiographic imaging(n=10) were performed in 18 patients(M:F = 12:6, mean age: 45 years) with histologically proven primary HPs. We evaluated the imaging findings of HPs with respect to site, shape, size, signal intensity, enhancement characteristics, vascular signal voids, calcification, bony and adjacent sinus involvement, and angiographic findings. HPs were meningeal in 14 cases and nonmeningeal in four. Meningeal HPs were located in the parasagittal region(n=8), convexity(n=3), intradural extramedullary space(n=1), choroid plexus(n=1), and olfactory groove(n=1). Nonmeningeal HPs were located in the masticator space(n=2), paraspinal area(n=1) and supraclavicular area(n=1). The mean maximal dimension of tumors was about 5.4cm and their shape was papillary(n=8) or lobulated(n=7). MR images showed high(n=13) or iso(n=3) signal intensities on T2W1, and heterogeneity on T2W1(n=9). Vascular signal voids in the mass were seen in all cases, while in two cases, CT scanning showed nodular dense calcification. Bone destruction was present in six cases, but no hyperostosis was found. In five cases, the superior sagittal sinus was involved. Angiographic images revealed highly vascular masses supplied by the internal carotid artery(n=5), external carotid artery(n=8), descending scapular artery(n=1) and radiculomedullary artery(n=1), with delayed tumor blush during the capillary and venous phase in which there was no arteriovenous shunt. HP is one of the extra-axial tumors in which there is hypervascularity, aggressive bony destruction arising in the meningeal and extrameningeal area, and heterogeneous high

Can CT and MR Shape and Textural Features Differentiate Benign Versus Malignant Pleural Lesions?

Science.gov (United States)

Pena, Elena; Ojiaku, MacArinze; Inacio, Joao R; Gupta, Ashish; Macdonald, D Blair; Shabana, Wael; Seely, Jean M; Rybicki, Frank J; Dennie, Carole; Thornhill, Rebecca E

2017-10-01

The study aimed to identify a radiomic approach based on CT and or magnetic resonance (MR) features (shape and texture) that may help differentiate benign versus malignant pleural lesions, and to assess if the radiomic model may improve confidence and accuracy of radiologists with different subspecialty backgrounds. Twenty-nine patients with pleural lesions studied on both contrast-enhanced CT and MR imaging were reviewed retrospectively. Three texture and three shape features were extracted. Combinations of features were used to generate logistic regression models using histopathology as outcome. Two thoracic and two abdominal radiologists evaluated their degree of confidence in malignancy. Diagnostic accuracy of radiologists was determined using contingency tables. Cohen's kappa coefficient was used to assess inter-reader agreement. Using optimal threshold criteria, sensitivity, specificity, and accuracy of each feature and combination of features were obtained and compared to the accuracy and confidence of radiologists. The CT model that best discriminated malignant from benign lesions revealed an AUC CT  = 0.92 ± 0.05 (P textural and shape analysis may help distinguish malignant from benign lesions. A radiomics-based approach may increase diagnostic confidence of abdominal radiologists on CT and MR and may potentially improve radiologists' accuracy in the assessment of pleural lesions characterized by MR. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Primary muscular hydatidosis. US, CT and MR findings

Energy Technology Data Exchange (ETDEWEB)

Alexiadis, G.; Deftereos, S.; Manavis, J. [Democritus Univ. of Thrace, Alexandroupolis (Greece). Dept. of Radiology; Lambropoulou, M.; Papadopoulos, N. [Democritus Univ. of Thrace, Alexandroupolis (Greece). Dept. of Pathology

2002-07-01

We present a rare case of primary muscular hydatidosis in the left thigh of a 40-year-old female patient. US, CT and MR imaging showed a typical multilocular hydatid cyst deep in the vastus intermedius and vastus medialis muscles. Histopathological examination, which followed surgical excision, established the diagnosis of echinococcus cyst.

Primary muscular hydatidosis. US, CT and MR findings

International Nuclear Information System (INIS)

Alexiadis, G.; Deftereos, S.; Manavis, J.; Lambropoulou, M.; Papadopoulos, N.

2002-01-01

We present a rare case of primary muscular hydatidosis in the left thigh of a 40-year-old female patient. US, CT and MR imaging showed a typical multilocular hydatid cyst deep in the vastus intermedius and vastus medialis muscles. Histopathological examination, which followed surgical excision, established the diagnosis of echinococcus cyst

CT and MR imaging of acute cerebellar ataxia

International Nuclear Information System (INIS)

Shoji, H.; Hirai, S.; Ishikawa, K.; Aramaki, M.; Sato, Y.; Abe, T.; Kojima, K.

1991-01-01

An adult female showed mild cerebellar ataxia and CSF pleocytosis following an acute infection of the upper respiratory tract, and was diagnosed as having acute cerebellar ataxia (ACA). CT and MR appearances in the acute stage revealed moderate swelling of the cerebellum and bilaterally increased signal intensity in the cerebellar cortex. (orig.)

Solitary pulmonary nodules: Comparison of dynamic first-pass contrast-enhanced perfusion area-detector CT, dynamic first-pass contrast-enhanced MR imaging, and FDG PET/CT.

Science.gov (United States)

Ohno, Yoshiharu; Nishio, Mizuho; Koyama, Hisanobu; Seki, Shinichiro; Tsubakimoto, Maho; Fujisawa, Yasuko; Yoshikawa, Takeshi; Matsumoto, Sumiaki; Sugimura, Kazuro

2015-02-01

To prospectively compare the capabilities of dynamic perfusion area-detector computed tomography (CT), dynamic magnetic resonance (MR) imaging, and positron emission tomography (PET) combined with CT (PET/CT) with use of fluorine 18 fluorodeoxyglucose (FDG) for the diagnosis of solitary pulmonary nodules. The institutional review board approved this study, and written informed consent was obtained from each subject. A total of 198 consecutive patients with 218 nodules prospectively underwent dynamic perfusion area-detector CT, dynamic MR imaging, FDG PET/CT, and microbacterial and/or pathologic examinations. Nodules were classified into three groups: malignant nodules (n = 133) and benign nodules with low (n = 53) or high (n = 32) biologic activity. Total perfusion was determined with dual-input maximum slope models at area-detector CT, maximum and slope of enhancement ratio at MR imaging, and maximum standardized uptake value (SUVmax) at PET/CT. Next, all indexes for malignant and benign nodules were compared with the Tukey honest significant difference test. Then, receiver operating characteristic analysis was performed for each index. Finally, sensitivity, specificity, and accuracy were compared with the McNemar test. All indexes showed significant differences between malignant nodules and benign nodules with low biologic activity (P Dynamic perfusion area-detector CT is more specific and accurate than dynamic MR imaging and FDG PET/CT in the diagnosis of solitary pulmonary nodules in routine clinical practice. © RSNA, 2014.

Indirect MR-arthography in the fellow up of autologous osteochondral transplantation; Indirekte MR-Arthrographie zur Verlaufskontrolle nach autologer osteochondraler Transplantation

Energy Technology Data Exchange (ETDEWEB)

Herber, S.; Pitton, M.B.; Kalden, P.; Thelen, M.; Kreitner, K.F. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Runkel, M. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Unfallchirurgie

2003-02-01

following autologous osteochondral transplantation. Assessment of transplant vitality, osseous fixation and stability is possible. (orig.) [German] Zielsetzung: Evaluation der Befunde nach indirekter MR-Arthrographie bei Patienten mit autologer osteochondraler Transplantation. Patienten und Methoden: 10 konsekutive Patienten mit einer Mosaik-Plastik wurden drei, 6 und 12 Monate nach dem Eingriff mittels indirekter MR-Arthrographie untersucht. Das MR-Protokoll bei 1,5T beinhaltete neben nativen PD- und T{sub 2}-gewichteten TSE-Sequenzen mit und ohne Fett-Suppression T{sub 1}-gewichtete, fettsupprimierte SE-Sequenzen vor und unmittelbar nach Kontrastmittelgabe sowie nach Bewegung des Gelenkes. Die Bildanalyse wurde gemeinsam von zwei Radiologen durchgefuehrt und beinhaltete die Auswertung der Signalintensitaet (SI) und Integritaet des knoechernen Zylinders ebenso wie der Knorpeloberflaeche, das Vorhandensein eines Knochenmarkoedems und eines Gelenkergusses. Ergebnisse: Drei Monate nach dem Eingriff zeigte sich in allen Faellen in der T{sub 2}-TSE-Sequenz ein ausgepraegtes Knochenmarkoedem auf Empfaenger- und Donorseite, korrespondierend zu einem deutlichem Signalintensitaetsanstieg nach Kontrastmittelgabe. Die Grenzzone zwischen dem Transplantat und dem originaerem Knochen zeigte eine erhoehte SI nach drei und 6 Monaten in der T{sub 2}-TSE-Sequenz sowie nach i.v. Gd-DTPA-Gabe. Eine Transplantatdislokation wurde in keinem Fall beobachtet. Als Zeichen der Vitalitaet des osteochondralen Transplantats normalisierte sich das Marksignal in der T{sub 1}-SE-Sequenz in den meisten Faellen nach 6 bzw. 12 Monaten. Die indirekte MR-Arthrographie war dem Nativ-Scan ueberlegen bei der Beurteilung der knorpeligen Ueberdeckung des Transplantats. In allen Faellen zeigte sich eine komplette Ueberdeckung des knoechernen Zylinders mit Gelenkknorpel. Transplantierter und originaerer hyaliner Knorpel zeigten einen deutlichen Anstieg der SI in der indirekten MR-Arthrographie. Signalalterationen und

Image Fusion of CT and MR with Sparse Representation in NSST Domain

Directory of Open Access Journals (Sweden)

Chenhui Qiu

2017-01-01

Full Text Available Multimodal image fusion techniques can integrate the information from different medical images to get an informative image that is more suitable for joint diagnosis, preoperative planning, intraoperative guidance, and interventional treatment. Fusing images of CT and different MR modalities are studied in this paper. Firstly, the CT and MR images are both transformed to nonsubsampled shearlet transform (NSST domain. So the low-frequency components and high-frequency components are obtained. Then the high-frequency components are merged using the absolute-maximum rule, while the low-frequency components are merged by a sparse representation- (SR- based approach. And the dynamic group sparsity recovery (DGSR algorithm is proposed to improve the performance of the SR-based approach. Finally, the fused image is obtained by performing the inverse NSST on the merged components. The proposed fusion method is tested on a number of clinical CT and MR images and compared with several popular image fusion methods. The experimental results demonstrate that the proposed fusion method can provide better fusion results in terms of subjective quality and objective evaluation.

CT, PET and MR-Imaging in experimental baromedical research

DEFF Research Database (Denmark)

Hansen, Kasper

Pa pressurisation, and repeatedly after 500 kPa/min decompression. After MRI, venous bubble development was monitored using ultrasound. Second, preclinical μCT, PET/MRI, and high-field 9.4 T MR-Imaging systems evaluated changes in cerebral standard uptake value (SUV) of F-FDG, changes in cerebral blood flow (delta...... it is intrinsically difficult to study humans or animals inside a pressure chamber. We have developed a preclinical pressure chamber system compatible with CT, PET and MR-imaging during pressurisation up to 1.013 mPa, which allows for anatomical visualisations and measurements of certain physiological processes...... in vivo during pressurisation. Material and methods: Anaesthetised rats (simulated diving and control groups) underwent the following imaging protocols: First, a 3T clinical MRI-system was employed to evaluate in vivo cerebral relaxation parameters (T1, T2 and T2*). MRI was performed before, during 709 k...

Clinical significance of creative 3D-image fusion across multimodalities [PET + CT + MR] based on characteristic coregistration

International Nuclear Information System (INIS)

Peng, Matthew Jian-qiao; Ju Xiangyang; Khambay, Balvinder S.; Ayoub, Ashraf F.; Chen, Chin-Tu; Bai Bo

2012-01-01

Objective: To investigate a registration approach for 2-dimension (2D) based on characteristic localization to achieve 3-dimension (3D) fusion from images of PET, CT and MR one by one. Method: A cubic oriented scheme of“9-point and 3-plane” for co-registration design was verified to be geometrically practical. After acquisiting DICOM data of PET/CT/MR (directed by radiotracer 18 F-FDG etc.), through 3D reconstruction and virtual dissection, human internal feature points were sorted to combine with preselected external feature points for matching process. By following the procedure of feature extraction and image mapping, “picking points to form planes” and “picking planes for segmentation” were executed. Eventually, image fusion was implemented at real-time workstation mimics based on auto-fuse techniques so called “information exchange” and “signal overlay”. Result: The 2D and 3D images fused across modalities of [CT + MR], [PET + MR], [PET + CT] and [PET + CT + MR] were tested on data of patients suffered from tumors. Complementary 2D/3D images simultaneously presenting metabolic activities and anatomic structures were created with detectable-rate of 70%, 56%, 54% (or 98%) and 44% with no significant difference for each in statistics. Conclusion: Currently, based on the condition that there is no complete hybrid detector integrated of triple-module [PET + CT + MR] internationally, this sort of multiple modality fusion is doubtlessly an essential complement for the existing function of single modality imaging.

Treatment of osteoid osteoma using CT-guided radiofrequency ablation versus MR-guided laser ablation: A cost comparison

International Nuclear Information System (INIS)

Maurer, M.H.; Gebauer, B.; Wieners, G.; De Bucourt, M.; Renz, D.M.; Hamm, B.; Streitparth, F.

2012-01-01

Objective: To compare the costs of CT-guided radiofrequency ablation (RFA) and MR-guided laser ablation (LA) for minimally invasive percutaneous treatment of osteoid osteoma. Materials and methods: Between November 2005 and October 2011, 20 patients (14 males, 6 females, mean age 20.3 ± 9.1 years) underwent CT-guided RFA and 24 patients (18 males, 6 females; mean age, 23.8 ± 13.8 years) MR-guided LA (open 1.0 Tesla, Panorama HFO, Philips, Best, Netherlands) for osteoid osteoma diagnosed on the basis of clinical presentation and imaging findings. Prorated costs of equipment use (purchase, depreciation, and maintenance), staff costs, and expenditure for disposables were identified for CT-guided RFA and MR-guided LA procedures. Results: The average total costs per patient were EUR 1762 for CT-guided RFA and EUR 1417 for MR-guided LA. These were (RFA/LA) EUR 92/260 for equipment use, EUR 149/208 for staff, and EUR 870/300 for disposables. Conclusion: MR-guided LA is less expensive than CT-guided RFA for minimally invasive percutaneous ablation of osteoid osteoma. The higher costs of RFA are primarily due to the higher price of the disposable RFA probes.

The CT and MR evaluation of migrational disorders of the brain. Pt. 1

International Nuclear Information System (INIS)

Byrd, S.E.; Osborn, R.E.; Bohan, T.P.; Texas Univ., Houston; Naidich, T.P.

1989-01-01

The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria-pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (part I) deals with our patients with lissencephaly and pachygyria. It emphasizes their characteristic CT and MR findings along with their clinical presentation and course. These patients presented with one or a combination of the following symptoms, hypotonia, seizures, failure to thrive, microcephaly and occasionally hydrocephalus. These two groups of migrational disorders have abnormalities affecting the gyral-sulcal pattern of the cortex and gray-white matter distribution of the brain. MR provided better delineation of these disorders than CT. Because some forms of the migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling. (orig.)

Is hepatotropic contrast enhanced MR a more effective method in differential diagnosis of hemangioma than multi-phase CT and unenhanced MR?

Directory of Open Access Journals (Sweden)

Markiet Karolina

2011-04-01

Full Text Available Abstract Background Cavernous hemangiomas are the most frequent neoplasms of the liver and in routine clinical practice they often need to be differentiated from malignant tumors and other benign focal lesions. The purpose of this study is to evaluate whether diagnostic accuracy of magnetic resonance imaging (MRI of hepatic hemangiomas, showing atypical pattern on US, improves with the use of Gd-BOPTA in comparison with contrast-enhanced multi-phase computed tomography (CT. Methods 178 consecutive patients with ambiguous hepatic masses showing atypical hyperechoic pattern on grey-scale US, underwent unenhanced and contrast-enhanced multi-phase multi-detector CT and MR (1.5T with the use of liver-specific contrast medium gadobenate dimeglumine (Gd-BOPTA. After intravenous contrast administration arterial (HAP, venous-portal (PVP, equilibrium phases (EP both in CT and MR and additionally hepatobiliary phase (HBP in MR were obtained. 398 lesions have been detected including 99 hemangiomas and 299 other lesions. Results In non-enhanced MDCT examination detection of hemangiomas was characterized by sensitivity of 76%, specificity of 90%, PPV of 71%, NPV of 92% and accuracy of 86%. Non-enhanced MR examination showed sensitivity of 98%, specificity of 99%, PPV of 99%, NPV of 99% and accuracy of 99%. After intravenous administration of contrast medium in MR the mentioned above parameters did not increase significantly. Conclusion Gd-BOPTA-enhanced MR in comparison with unenhanced MRI does not improve diagnostic accuracy in discriminating hemangiomas that show non-specific appearance in ultrasound examination. Unenhanced MR as a method of choice should directly follow US in course of diagnostic algorithm in differentiation of hemangiomas from other liver tumors.

SU-C-18A-05: Registration Accuracy of MR-Based Images to On-Board Megavoltage Cone-Beam CT for Brain Patient Setup

International Nuclear Information System (INIS)

Pinnaduwage, D S; Chen, J; Descovich, M; Pouliot, J; Hwang, Ken-Ping

2014-01-01

Purpose: To quantify the difference in isocenter shifts when co-registering MR and MR-based pseudo CTs (pCT) with on-board megavoltage conebeam CT (CBCT) images. Methods: Fast Spoiled Gradient Echo MRs were used to generate pCTs (research version of Advantage Sim MD™, GE Healthcare) for ten patients who had prior brain radiotherapy. The planning CT (rCT) for each was co-registered with the MR, and the plan isocenter and two other reference points were transferred to the MR and pCT. CBCT images (with the machine isocenter) from a single treatment day were coregistered with the 3 test images (MR, pCT and rCT), by two observers and by an automated registration algorithm. The reference points were used to calculate patient shifts and rotations from the registrations. The shifts calculated from the test image registrations were compared to each other and to the shifts performed by the therapists who treated the patients on that day. Results: The average difference in absolute value between the isocenter shifts from the MR-, pCT- and rCT-CBCT registrations, and the therapist shifts, were 2.02, 3.01 and 0.89 mm (craniocaudal), 1.14, 1.34 and 0.46 mm (lateral), and 1.37, 3.43 and 1.43 mm (vertical), respectively. The MR- and pCT-CBCT registrations differed by 1.99, and 2.53 mm (craniocaudal), 1.36, and 1.37 mm (lateral), and 0.74 and 2.34 mm (vertical), respectively, from the average rCT-CBCT shifts. On average, differences of 2.39 (craniocaudal), 1.28 (lateral) and 2.84 mm (vertical) were seen between the MR and pCT shifts. Rotations relative to the CBCT coordinate system were on average <2° for the MR and rCT, and <6° for the pCT. Conclusion: In this study, FSPGR MR-CBCT registrations were more precise compared to the pCT-CBCT registrations. For improved accuracy, MR sequences that are optimal for bony anatomy visualization are necessary. GE healthcare has provided a research version of Advantage Sim MD to UCSF. No financial support was provided

Accuracy of spiral CT and 3D reconstruction in the detection of acute pulmonary embolism - development of an animal model using porcine lungs and technical specimens. Development of an animal model using porcine lungs and technical specimens; Diagnostik der akuten Lungenembolie mittels Spiral-CT und 3D-Rekonstruktion. Entwicklung eines Tiermodells und technischer Probekoerper im Ex-vivo-Experiment

Energy Technology Data Exchange (ETDEWEB)

Ries, B.G. [Klinik und Poliklinik fuer Radiologie, Univ. Mainz (Germany); Klinik fuer Radiologische Diagnostik, RWTH Aachen (Germany); Kauczor, H.U.; Thelen, M. [Klinik und Poliklinik fuer Radiologie, Univ. Mainz (Germany); Konerding, M.A. [Anatomisches Inst., Mainz Univ (Germany)

2001-02-01

von Modellen zur Evaluierung der Spiral-CT und 3D-Rekonstruktion im Nachweis der akuten Lungenembolie (LE) im Ex-vivo-Experiment. Material und Methoden: Standardisierte kuenstliche Emboli definierter Groesse und Geometrie wurden in Schweinelungen eingebracht. Ausguesse der embolisierten Gefaessbaeume mit roentgenkontrastgebendem Kunstharz simulierten das CT-morphologische Vollbild einer Lungenembolie. Die Bilddaten wurden dreidimensional rekonstruiert und die Exaktheit der detektierten Emboluslokalisation durch Korrelation mit dem Originalpraeparat verifiziert. Messungen an technischen Probekoerpern mit eingeschlossenen Emboli definierter Groesse sollten die Messgenauigkeit der kombinierten Spiral-CT-/3D Rekonstruktion in Abhaengigkeit von deren Orientierung zur z-Achse und von der Rekonstruktionstechnik (standardisiert und kontrastadaptiert) aufzeigen. Ergebnisse: Fuer die Detektion und Lokalisation ergab sich eine Uebereinstimmung zwischen Spiral-CT-/3D-Rekonstruktion und dem Originalpraeparat von {proportional_to}91%. Die Messungen der technischen Probekoerper ergaben deutliche Abweichungen in Abhaengigkeit von der Groesse, der Orientierung zur z-Achse und der Rekonstruktionstechnik. Hierbei traten Ueberschaetzungen von bis zu 4 mm, Unterschaetzungen von bis zu 2,2 mm auf. Bei Praeparaten mit Hoehen von 14-26 mm traten Schwankungen in einer Groessenordnung von ca. {+-}1,5 mm ({proportional_to}6-11%) auf. Schlussfolgerung: Die vorgestellten Ex-vivo-Modelle sind zur Simulation der akuten Lungenembolie gut geeignet. Die Genauigkeit der Embolusdetektion wird durch Lokalisation, Groesse, Orientierung und Rekonstruktionstechnik beeinflusst. (orig.)

CT and MR imaging features in patients with intracranial dolichoectasia

Energy Technology Data Exchange (ETDEWEB)

Tien, Kuang Lung; Yu, In Kyu; Yoon, Sook Ja; Yoon, Yong Kyu [Eulji College of Medicine, Eulji Hospital, Seoul (Korea, Republic of)

2000-02-01

To describe the CT and MR imaging features in patients with intracranial dolichoectasia. The CT (n=3D21), MR (n=3D20) and MRA (n=3D11) imaging features seen in 28 patients (M:F=3D12:16 aged between 65 and 82 (mean, 65) years) with intracranial dolichoectasia were retrospectively reviewed with regard to involved sites, arterial changes (maximum diameter, wall calcification, high signal intensity in the involved artery, as seen on T1-weighted MR images), infarction, hemorrhagic lesion, compression of brain parenchyma or cranial nerves, hydrocephalus and brain atrophy. Involved sites were classified as either type 1 (involvement of only the posterior circulation), type 2 (only the anterior circulation), or type 3 (both). In order of frequency, involved sites were type 1 (43%), type 3 (36%) and type 2 (22%). Dolichoectasia was more frequently seen in the posterior circulation (79%) than in the anterior (57%). Arterial changes as seen on T1-weighted MR images, included dolichoectasia (mean maximum diameter 7.4 mm in the distal internal carotid artery, and 6.7 mm in the basilar artery), wall calcification (100% in involved arteries) and high signal intensity in involved. Cerebral infarction in the territory of the involved artery was found in all patients, and a moderate degree of infarct was 87%. Hemorrhagic lesions were found in 19 patients (68%); these were either lobar (53%), petechial (37%), or subarachnoid (16%), and three patients showed intracranial aneurysms, including one case of dissecting aneurysm. In 19 patients (68%), lesions were compressed lesions by the dolichoectatic arteries, and were found-in order of descending frequency-in the medulla, pons, thalamus, and cerebellopontine angle cistern. Obstructive hydrocephalus was found in two patients (7%), and 23 (82%) showed a moderate degree of brain atrophy. In patients with intracranial dolichoectasia, moderate degrees of cerebral infarction and brain atrophy in the territory of involved arteries, as well as

Intramuscular ganglia arising from the superior tibiofibular joint: CT and MR evaluation

International Nuclear Information System (INIS)

Bianchi, S.; Abdelwahab, I.F.; Kenan, S.; Zwass, A.; Ricci, G.; Palomba, G.

1995-01-01

To evaluate the role of magnetic resonance imaging (MRI) and computed tomography (CT) in the diagnosis of intramuscular ganglia (IMG) that arise from the superior tibiofibular joint (STFJ). Our series consisted of three men and three women. Four patients were studied by MRI, one by CT only, and two by both modalities. Contrast was used in one of the two patients studied by CT. MRI was obtained in at least two orthogonal planes to demonstrate the relation of the ganglia to STFJ. The MR and CT appearance of these ganglia was basically that of a well-defined soft tissue mass with low attenuation on CT images consistent with the presence of fluid. On MR studies, they had an isointense signal on T1-weighted images and a homogenous high-intensity signal on T2-weighted images. MRI demonstrated the attachment of these ganglia to the STFJ. CT and MRI were effective, noninvasive modalities in the evaluation of IMG. The imaging features on both modalities were consistent with the presence of fluid-containing lesions that had close proximity and were attached to the STFJ. The combination of location and the fluid consistency of these lesions facilitated the diagnosis. (orig.)

Amyloid goiter in a child - US, CT and MR evaluation

International Nuclear Information System (INIS)

Perez Fontan, F.J.; Mosquera Oses, J.; Pombo Felipe, F.; Rodriguez Sanchez, I.; Arnaiz Pena, S.

1992-01-01

There are few radiological descriptions of amyloid goiter, basically in adult patients or oriental origin. We present a ten-year-old boy with Still's disease and secondary thyroid amyloidosis, describing the US, CT and MR findings. (orig.)

Occult cerebral vascular malformation: High-field (2.0 T) MR imaging and comparison with CT

International Nuclear Information System (INIS)

Chang, Kee Hyun; Chung, Jin Wook; Han, Moon Hee; Kang, Heung Sik; Han, Man Chung; Kim, Chu Wan

1989-01-01

Extensive experience with CT has led to the recognition of criteria for the diagnosis of occult cerebral vascular malformation. MR demonstrated all lesions as hemorrhage foci. The most common and typical MR findings of OVCM was circumscribed thick hypointense rim on T2-weighted images (T2-Wls) representing hemosiderin deposit with various central intensities suggesting the presence of hematomas in different stages (11 lesions). Among these. the recurrent hemorrhage in small amount produced the characteristic 'a bunch of grape' appearance. But, small OCVM less than 1 cm in diameter was identified as a small homogeneous hypointense nodule on T2-Wls with sharp (6 lesions) or fade-out (1 lesions) border. There were 2 lesions showing atypical findings such as dense hemosiderin rin with central lacuma or bilobed subacute hematoma. As the associated MR findings which strongly suggest the diagnosis of OCVM signal void due to feeding or draining vessels was found in 4, lesions and the surrounding focal cortical atrophy or leukomalacia in 2 lesions. The predilection site of OCVM was subcortical (8 lesions) and periventricular (6 cases) location. CT depicted 16 of the 20 lesions, but missed 4 lesions of small OCVM. CT alone did not permit definitive diagnosis of OCVM is most cases. Fifteen lesions demonstrated on CT contained somewhat hyperdense area in central or peripheral locations. Peripheral hyperdense area corresponded to the dense hemosiderin deposit on MR and central one to the hematoma formed by recent hemorrhage. Low density area on CT usually corresponded to liquefied subacute hematoma on MR

Bosniak classification system: a prospective comparison of CT, contrast-enhanced US, and MR for categorizing complex renal cystic masses.

Science.gov (United States)

Graumann, Ole; Osther, Susanne Sloth; Karstoft, Jens; Hørlyck, Arne; Osther, Palle Jörn Sloth

2016-11-01

Background The Bosniak classification was originally based on computed tomographic (CT) findings. Magnetic resonance (MR) and contrast-enhanced ultrasonography (CEUS) imaging may demonstrate findings that are not depicted at CT, and there may not always be a clear correlation between the findings at MR and CEUS imaging and those at CT. Purpose To compare diagnostic accuracy of MR, CEUS, and CT when categorizing complex renal cystic masses according to the Bosniak classification. Material and Methods From February 2011 to June 2012, 46 complex renal cysts were prospectively evaluated by three readers. Each mass was categorized according to the Bosniak classification and CT was chosen as gold standard. Kappa was calculated for diagnostic accuracy and data was compared with pathological results. Results CT images found 27 BII, six BIIF, seven BIII, and six BIV. Forty-three cysts could be characterized by CEUS, 79% were in agreement with CT (κ = 0.86). Five BII lesions were upgraded to BIIF and four lesions were categorized lower with CEUS. Forty-one lesions were examined with MR; 78% were in agreement with CT (κ = 0.91). Three BII lesions were upgraded to BIIF and six lesions were categorized one category lower. Pathologic correlation in six lesions revealed four malignant and two benign lesions. Conclusion CEUS and MR both up- and downgraded renal cysts compared to CT, and until these non-radiation modalities have been refined and adjusted, CT should remain the gold standard of the Bosniak classification.

Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests

OpenAIRE

Mustafa Demir; Türkay Toklu; Mohammad Abuqbeitah; Hüseyin Çetin; H. Sezer Sezgin; Nami Yeyin; Kerim Sönmezoğlu

2018-01-01

Objective: The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. Methods: According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated...

Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests

OpenAIRE

Demir, Mustafa; Toklu, Türkay; Abuqbeitah, Mohammad; Çetin, Hüseyin; Sezgin, H. Sezer; Yeyin, Nami; Sönmezoğlu, Kerim

2018-01-01

Objective: The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. Methods: According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated asp...

Comparison of CT during arterial portography, delayed iodine CT, and MR imaging for the preoperative evaluation of hepatic tumors

International Nuclear Information System (INIS)

Nelson, R.C.; Chezmar, J.L.; Sugarbaker, P.H.; Bernardino, M.E.

1988-01-01

Twenty-eight patients with neoplastic involvement of the liver were studied with CT during arterial portography, delayed iodine CT, and MR imaging, to determine the number, size, and location of focal hepatic lesions prior to hepatic tumor surgery. The MR pulse-sequences used included T1- and T2-weighted spin-echo (SE) sequences and inversion-recovery (IR) sequences at 0.5 T, 1.5 T, or both. Results were compared with operative and pathologic findings. The sensitivities for the detection of individual focal lesions are as follows: CT during arterial portography, delayed iodine CT, 77%, IR at 0.5 T, 74%; T1-weighted SE at 0.5 T, 69%; T2-weighted SE at 1.5 T, 55%, IR at 1.5 T, 50%; T2-weighted SE at 0.5 T, 48%, and T1-weighted SE at 1.5 T, 31%. The positive predictive values ranged from 88% to 100% for all techniques. The authors' data suggest that CT during arterial portography is a superior technique for evaluating patients prior to hepatic tumor surgery

Feasibility of simultaneous PET/MR of the carotid artery: first clinical experience and comparison to PET/CT

DEFF Research Database (Denmark)

Ripa, Rasmus Sejersten; Knudsen, Andreas; Hag, Anne Mette Fisker

2013-01-01

The study aimed at comparing PET/MR to PET/CT for imaging the carotid arteries in patients with known increased risk of atherosclerosis. Six HIV-positive men underwent sequential PET/MR and PET/CT of the carotid arteries after injection of 400 MBq of 18F-FDG. PET/MR was performed a median of 131......) indicating that the luminal 18F-FDG content had minimal influence on the values. The study shows for the first time that simultaneous PET/MR of the carotid arteries is feasible in patients with increased risk of atherosclerosis. Quantification of 18F-FDG uptake correlated well between PET/MR and PET...

Comparison of MR-based attenuation correction and CT-based attenuation correction of whole-body PET/MR imaging

Energy Technology Data Exchange (ETDEWEB)

Izquierdo-Garcia, David [Mount Sinai School of Medicine, Translational and Molecular Imaging Institute, New York, NY (United States); Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA (United States); Sawiak, Stephen J. [University of Cambridge, Wolfson Brain Imaging Centre, Cambridge (United Kingdom); Knesaurek, Karin; Machac, Joseph [Mount Sinai School of Medicine, Division of Nuclear Medicine, Department of Radiology, New York, NY (United States); Narula, Jagat [Mount Sinai School of Medicine, Department of Cardiology, Zena and Michael A. Weiner Cardiovascular Institute and Marie-Josee and Henry R. Kravis Cardiovascular Health Center, New York, NY (United States); Fuster, Valentin [Mount Sinai School of Medicine, Department of Cardiology, Zena and Michael A. Weiner Cardiovascular Institute and Marie-Josee and Henry R. Kravis Cardiovascular Health Center, New York, NY (United States); The Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid (Spain); Fayad, Zahi A. [Mount Sinai School of Medicine, Translational and Molecular Imaging Institute, New York, NY (United States); Mount Sinai School of Medicine, Department of Cardiology, Zena and Michael A. Weiner Cardiovascular Institute and Marie-Josee and Henry R. Kravis Cardiovascular Health Center, New York, NY (United States); Mount Sinai School of Medicine, Department of Radiology, New York, NY (United States)

2014-08-15

The objective of this study was to evaluate the performance of the built-in MR-based attenuation correction (MRAC) included in the combined whole-body Ingenuity TF PET/MR scanner and compare it to the performance of CT-based attenuation correction (CTAC) as the gold standard. Included in the study were 26 patients who underwent clinical whole-body FDG PET/CT imaging and subsequently PET/MR imaging (mean delay 100 min). Patients were separated into two groups: the alpha group (14 patients) without MR coils during PET/MR imaging and the beta group (12 patients) with MR coils present (neurovascular, spine, cardiac and torso coils). All images were coregistered to the same space (PET/MR). The two PET images from PET/MR reconstructed using MRAC and CTAC were compared by voxel-based and region-based methods (with ten regions of interest, ROIs). Lesions were also compared by an experienced clinician. Body mass index and lung density showed significant differences between the alpha and beta groups. Right and left lung densities were also significantly different within each group. The percentage differences in uptake values using MRAC in relation to those using CTAC were greater in the beta group than in the alpha group (alpha group -0.2 ± 33.6 %, R{sup 2} = 0.98, p < 0.001; beta group 10.31 ± 69.86 %, R{sup 2} = 0.97, p < 0.001). In comparison to CTAC, MRAC led to underestimation of the PET values by less than 10 % on average, although some ROIs and lesions did differ by more (including the spine, lung and heart). The beta group (imaged with coils present) showed increased overall PET quantification as well as increased variability compared to the alpha group (imaged without coils). PET data reconstructed with MRAC and CTAC showed some differences, mostly in relation to air pockets, metallic implants and attenuation differences in large bone areas (such as the pelvis and spine) due to the segmentation limitation of the MRAC method. (orig.)

Comparison of MR-based attenuation correction and CT-based attenuation correction of whole-body PET/MR imaging

International Nuclear Information System (INIS)

Izquierdo-Garcia, David; Sawiak, Stephen J.; Knesaurek, Karin; Machac, Joseph; Narula, Jagat; Fuster, Valentin; Fayad, Zahi A.

2014-01-01

The objective of this study was to evaluate the performance of the built-in MR-based attenuation correction (MRAC) included in the combined whole-body Ingenuity TF PET/MR scanner and compare it to the performance of CT-based attenuation correction (CTAC) as the gold standard. Included in the study were 26 patients who underwent clinical whole-body FDG PET/CT imaging and subsequently PET/MR imaging (mean delay 100 min). Patients were separated into two groups: the alpha group (14 patients) without MR coils during PET/MR imaging and the beta group (12 patients) with MR coils present (neurovascular, spine, cardiac and torso coils). All images were coregistered to the same space (PET/MR). The two PET images from PET/MR reconstructed using MRAC and CTAC were compared by voxel-based and region-based methods (with ten regions of interest, ROIs). Lesions were also compared by an experienced clinician. Body mass index and lung density showed significant differences between the alpha and beta groups. Right and left lung densities were also significantly different within each group. The percentage differences in uptake values using MRAC in relation to those using CTAC were greater in the beta group than in the alpha group (alpha group -0.2 ± 33.6 %, R 2 = 0.98, p 2 = 0.97, p < 0.001). In comparison to CTAC, MRAC led to underestimation of the PET values by less than 10 % on average, although some ROIs and lesions did differ by more (including the spine, lung and heart). The beta group (imaged with coils present) showed increased overall PET quantification as well as increased variability compared to the alpha group (imaged without coils). PET data reconstructed with MRAC and CTAC showed some differences, mostly in relation to air pockets, metallic implants and attenuation differences in large bone areas (such as the pelvis and spine) due to the segmentation limitation of the MRAC method. (orig.)

CNS Involvement in Hemophagocytic Lymphohistiocytosis: CT and MR Findings

International Nuclear Information System (INIS)

Chung, Tae Woong

2007-01-01

Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder that is characterized by proliferation of benign histiocytes, and this commonly involves the liver, spleen, lymph nodes, bone marrow and central nervous system (CNS). We report here on the CT and MR imaging findings in a case of CNS HLH that showed multiple ring enhancing masses mimicking abscess or another mass on the CT and MR imaging. emophagocytic lymphohistiocytosis (HLH) is a rare disorder that is characterized by nonmalignant diffuse infiltration of multiple organs, including the central nervous system (CNS), by lymphocytes and histiocytes (1). Many radiologic reports describing diffuse white matter infiltrations, parenchymal atrophy and calcification have been published, but the characteristics of these findings remain non-specific, especially in immunocompromised patients. We present here a case of HLH in a 3-year-old boy who presented with multiple ring enhancing lesions involving the brain. In conclusion, although the CT and MRI findings of HLH with ring enhancing parenchymal lesions are nonspecific and mimic abscess, and especially in the immunosuppressed patients, increased diffusion at the center on DWI may be a finding of HLH to differentiate it from abscess, which has restricted diffusion at the center. However, the pathologic correlation with DWI according to the lesion stage certainly needs further study with a larger number of patients

Proton range shift analysis on brain pseudo-CT generated from T1 and T2 MR.

Science.gov (United States)

Pileggi, Giampaolo; Speier, Christoph; Sharp, Gregory C; Izquierdo Garcia, David; Catana, Ciprian; Pursley, Jennifer; Amato, Francesco; Seco, Joao; Spadea, Maria Francesca

2018-05-29

In radiotherapy, MR imaging is only used because it has significantly better soft tissue contrast than CT, but it lacks electron density information needed for dose calculation. This work assesses the feasibility of using pseudo-CT (pCT) generated from T1w/T2w MR for proton treatment planning, where proton range comparisons are performed between standard CT and pCT. MR and CT data from 14 glioblastoma patients were used in this study. The pCT was generated by using conversion libraries obtained from tissue segmentation and anatomical regioning of the T1w/T2w MR. For each patient, a plan consisting of three 18 Gy beams was designed on the pCT, for a total of 42 analyzed beams. The plan was then transferred onto the CT that represented the ground truth. Range shift (RS) between pCT and CT was computed at R 80 over 10 slices. The acceptance threshold for RS was according to clinical guidelines of two institutions. A γ-index test was also performed on the total dose for each patient. Mean absolute error and bias for the pCT were 124 ± 10 and -16 ± 26 Hounsfield Units (HU), respectively. The median and interquartile range of RS was 0.5 and 1.4 mm, with highest absolute value being 4.4 mm. Of the 42 beams, 40 showed RS less than the clinical range margin. The two beams with larger RS were both in the cranio-caudal direction and had segmentation errors due to the partial volume effect, leading to misassignment of the HU. This study showed the feasibility of using T1w and T2w MRI to generate a pCT for proton therapy treatment, thus avoiding the use of a planning CT and allowing better target definition and possibilities for online adaptive therapies. Further improvements of the methodology are still required to improve the conversion from MRI intensities to HUs.

CT and MR findings of langerhans cell histiocytois involving the spleen: a case report

Energy Technology Data Exchange (ETDEWEB)

Pyun, Hae Wook; Kim, Mee Eun; Kim, Jang Ho [Fatima Hospital, Taegu (Korea, Republic of)

2002-02-01

Langerhans cell histiocytosis (LCH) is systemic disease resulting from the proliferation and dissemination of abnormal histiocytic cells of the Langerhans cell system. Common sites of involvement include the skin, bone, bone marrow, lung, lymph nodes and central nervous system, and the condition manifests in variety of ways. We present the CT and MR findings of a case of LCH involving the spleen, an organ invloved relatively rarely. Post-contrast CT revealed multiple hypodense nodules. T1-weighted MR images of the spleen depicted no definitive lesion, but T2-weighted images showed abnormal low signals scattered throughout this organ. In addition, post-contrast, fat-saturated T1-weighted MR images lesions showed multiple, low-signal-intensity lesions.

A standardized CT/HRCT classification for occupational and environmental lung diseases of the German Federal Republic; Standardisierte CT/HRCT-Klassifikation der Bundesrepublik Deutschland fuer arbeits- und umweltbedingte Thoraxerkrankungen

Energy Technology Data Exchange (ETDEWEB)

Hering, K.G. [Radiologische Klinik, Knappschaftskrankenhaus Dortmund (Germany); Tuengerthal, S. [Roentgenabteilung, Thoraxklinik Heidelberg (Germany); Kraus, T. [Institut fuer Arbeitsmedizin, Universitaetsklinikum Aachen (Germany)

2004-05-01

unerlaesslicher Bestandteil der Diagnostik von Staublungenerkrankungen und anderen Inhalationsschaeden. Konsensfaehige Vereinbarungen ueber eine standardisierte Untersuchungstechnik und einheitliche Befundung existierten bislang aber nicht. Von der Arbeitsgemeinschaft ''Diagnostische Radiologie bei arbeits- und umweltbedingten Erkrankungen'' der Deutschen Roentgengesellschaft (DRG) wurde ein CT-Beurteilungsbogen eingesetzt, der auf Erfahrungen aus gutachtlichen Stellungnahmen, arbeitsmedizinischen nachgehenden Untersuchungen und Fortbildungskursen basiert und im Rahmen einer Multicenterstudie eingesetzt wurde. Ein weiter entwickeltes Schema einer internationalen Arbeitsgruppe (P.A. Gevenois, Belgien; K.G. Hering, T. Kraus, S. Tuengerthal, Deutschland; L. Kivisaari, T. Vehmas, Finnland; M. Letourneux, Frankreich; M.D. Crane, Grossbritannien; H. Arikawa, Y. Kusaka, N. Suganuma, Japan; J. Parker, USA) wurde international getestet. Es soll dazu dienen, die computertomographische Befundung der arbeits- und umweltbedingten Lungen- und Pleuraveraenderungen zu standardisieren und international Vergleiche zu ermoeglichen. Mit Hilfe von CT/HRCT-Referenzfilmen konnte diese reproduzierbare Vergleichbarkeit erreicht werden. Das Klassifizierungsschema hat einen rein deskriptiven Charakter, sodass alle Aspekte arbeits- und umweltbedingter Folgeerscheinungen an Parenchym und Pleura erfasst werden koennen. Obwohl einige der deskriptiven Bezeichnungen mit pneumokoniotischen Befunden verknuepft sind, wie z. B. rundliche Herde mit der Silikose oder interlobulaere septale und intralobulaere nichtseptale Linien sowie ''honeycombing'' mit der Asbestose, finden sich zahlreiche ueberlappende Bildmuster, die differenzialdiagnostisch zu diskutieren sind. (orig.)

PET/CT in lymphoma patients; PET-CT bei Lymphompatienten

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Steinert, H.C. [Universitaetsspital Zuerich, Klinik und Poliklinik fuer Nuklearmedizin (Switzerland)

2004-11-01

First results of PET/CT in Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL) are reported. From March 2001 to August 2004 822 PET/CT were performed at our clinic in lymphoma patients for primary staging, restaging after therapy, and diagnosis of recurrence. For coregistration non contrast-enhanced low-dose CT were used. Due to the exact anatomic localization of {sup 18}F-FDG accumulating lesions equivocal or false positive PET findings are avoided. In comparison to contrast enhanced CT, PET/CT has a higher sensitivity and specificity in patients with HD and aggressive NHL. Integration of PET/CT in treatment planning of radiation therapy optimizes the field volume. Even in the initial phase of clinical evaluation, PET/CT has proven useful in staging and restaging of lymphoma. The exact anatomic localization of the PET findings is essential for a precise report, for treatment planning of radiation therapy, and for planning surgical biopsy. (orig.) [German] Erste Ergebnisse der PET-CT bei Morbus Hodgkin (HD) und den aggressiven Non-Hodgkin-Lymphomen (NHL) werden beschrieben. Von Maerz 2001 bis August 2004 wurden 822 PET-CT bei Lymphompatienten zum primaeren Staging, zum Restaging nach Therapie und zur Rezidivdiagnostik an unserer Klinik durchgefuehrt. Fuer die Koregistration wurde ein Low-dose-CT ohne i.v.-Kontrastmittel verwendet. Durch die exakte anatomische Zuordnung der {sup 18}F-FDG aufnehmenden Laesionen wurden unklare oder falsch-positive PET-Befunde vermieden. Die PET-CT erzielte im Vergleich zur KM-verstaerkten CT eine hoehere Sensitivitaet und Spezifitaet bei Patienten mit HD und aggressiven NHL. Die Integration der PET-CT in die Planung der Strahlentherapie fuehrte zu einer Optimierung der Feldgrenzen. Die PET-CT hat sich bereits in der Phase der initialen klinischen Evaluation als wertvoll beim Staging und Restaging von Lymphomen erwiesen. Die exakte anatomische Zuordnung der PET-Informationen ist fuer eine sichere Befundung

CT and MR findings in synovial chondromatosis of the temporo-mandibular joint: our experience and review of literature.

Science.gov (United States)

Testaverde, Lorenzo; Perrone, Anna; Caporali, Laura; Ermini, Antonella; Izzo, Luciano; D'Angeli, Ilaria; Impara, Luca; Mazza, Dario; Izzo, Paolo; Marini, Mario

2011-06-01

To compare Computed Tomography (CT) and Magnetic Resonance (MR) features and their diagnostic potential in the assessment of Synovial Chondromatosis (SC) of the Temporo-Mandibular Joint (TMJ). Eight patients with symptoms and signs compatible with dysfunctional disorders of the TMJ underwent CT and MR scan. We considered the following parameters: soft tissue involvement (disk included), osteostructural alterations of the joints, loose bodies and intra-articular fluid. These parameters were evaluated separately by two radiologists with a "double blinded method" and then, after agreement, definitive assessment of the parameters was given. CT and MR findings were compared. Histopathological results showed metaplastic synovia in all patients and therefore confirmed diagnosis of SC. MR resulted better than CT in the evaluation of all parameters except the osteostructural alterations of the joints, estimated with more accuracy by CT scan. CT scan is excellent to define bony surfaces of the articular joints and flogistic tissue but it fails in the detection of loose bodies when these are not yet calcified. MR scan therefore is the gold standard when SC is suspected since it can visualize loose bodies at early stage and also evaluate disk condition and eventual extra-articular tissues involvement. The use of T2-weighted images and contrast medium allows identifying intra-articular fluid, estimating its entity and discriminating from sinovial tissue. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

CT and MR findings in synovial chondromatosis of the temporo-mandibular joint: Our experience and review of literature

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Testaverde, Lorenzo, E-mail: doctor.lot@gmail.com [Department of Radiological Sciences, Policlinico Umberto I, University ' Sapienza' of Rome, Viale del Policlinico 155, 00161, Rome (Italy); Perrone, Anna; Caporali, Laura; Ermini, Antonella [Department of Radiological Sciences, Policlinico Umberto I, University ' Sapienza' of Rome, Viale del Policlinico 155, 00161, Rome (Italy); Izzo, Luciano; D' Angeli, Ilaria [Department of General Surgery ' Pietro Valdoni' , Policlinico Umberto I, University ' Sapienza' of Rome, Viale del Policlinico 155, 00161, Rome (Italy); Impara, Luca; Mazza, Dario [Department of Radiological Sciences, Policlinico Umberto I, University ' Sapienza' of Rome, Viale del Policlinico 155, 00161, Rome (Italy); Izzo, Paolo [Department of General Surgery ' Pietro Valdoni' , Policlinico Umberto I, University ' Sapienza' of Rome, Viale del Policlinico 155, 00161, Rome (Italy); Marini, Mario [Department of Radiological Sciences, Policlinico Umberto I, University ' Sapienza' of Rome, Viale del Policlinico 155, 00161, Rome (Italy)

2011-06-15

Objective: To compare Computed Tomography (CT) and Magnetic Resonance (MR) features and their diagnostic potential in the assessment of Synovial Chondromatosis (SC) of the Temporo-Mandibular Joint (TMJ). Materials and methods: Eight patients with symptoms and signs compatible with dysfunctional disorders of the TMJ underwent CT and MR scan. We considered the following parameters: soft tissue involvement (disk included), osteostructural alterations of the joints, loose bodies and intra-articular fluid. These parameters were evaluated separately by two radiologists with a 'double blinded method' and then, after agreement, definitive assessment of the parameters was given. CT and MR findings were compared. Results: Histopathological results showed metaplastic synovia in all patients and therefore confirmed diagnosis of SC. MR resulted better than CT in the evaluation of all parameters except the osteostructural alterations of the joints, estimated with more accuracy by CT scan. Conclusions: CT scan is excellent to define bony surfaces of the articular joints and flogistic tissue but it fails in the detection of loose bodies when these are not yet calcified. MR scan therefore is the gold standard when SC is suspected since it can visualize loose bodies at early stage and also evaluate disk condition and eventual extra-articular tissues involvement. The use of T2-weighted images and contrast medium allows identifying intra-articular fluid, estimating its entity and discriminating from sinovial tissue.

Hydatid disease of the spleen; Ultrasonography, CT and MR imaging

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Sinner, W.N. von; Stridbeck, H. (Dept. of Diagnostic Radiology, King Faisal Specialist Hospital, and Research Center, Riyadh (Saudi Arabia) Lund Univ. Hospital (Sweden))

1992-09-01

Seven patients with hydatid disease of the spleen were examined by radiography, ultrasound, CT, and in one case MR imaging. The observations were confirmed by patho-anatomic findings except in 2 patients where high indirect hemagglutination tests confirmed the diagnosis. (orig./MG).

Meningoencephalitis due to anthrax: CT and MR findings

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Yildirim, Hanefi; Koc, Mustafa; Murat, Ayse [Firat University, Department of Radiology, Elazig (Turkey); Kabakus, Nimet; Incekoey Girgin, Feyza [Firat University, Department of Paediatric Neurology, Elazig (Turkey)

2006-11-15

Anthrax is primarily a disease of herbivores, but it also causes cutaneous, respiratory and gastrointestinal infections in humans. Bacillus anthracis is an uncommon cause of meningitis and generally produces a haemorrhagic meningoencephalitis. We present the CT and MR findings of anthrax meningoencephalitis due to the cutaneous form of anthrax in a 12-year-old boy. They showed focal intracerebral haemorrhage with leptomeningeal enhancement. (orig.)

Three-Dimensional post-myelographic CT reconstruction in the diagnosis and therapy planning for spinal development disorders; Dreidimensionale postmyelographische CT-Rekonstruktion in der Diagnostik und Therapieplanung spinaler Entwicklungsstoerungen

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Wicht, L. [Strahlenklinik und Poliklinik, Virchow Klinikum, Humboldt-Univ. zu Berlin (Germany); Schedel, H. [Strahlenklinik und Poliklinik, Virchow Klinikum, Humboldt-Univ. zu Berlin (Germany); Benndorf, G. [Strahlenklinik und Poliklinik, Virchow Klinikum, Humboldt-Univ. zu Berlin (Germany); Beier, J. [Strahlenklinik und Poliklinik, Virchow Klinikum, Humboldt-Univ. zu Berlin (Germany); Haberl, H. [Neurochirurgische Abt., Virchow-Klinikum, Humboldt-Univ. zu Berlin (Germany); Felix, R. [Strahlenklinik und Poliklinik, Virchow Klinikum, Humboldt-Univ. zu Berlin (Germany)

1996-05-01

Dysrhaphia is often associated with severe osseous aberrations of the spine such as, for example scoliosis, hemivertebra, and synostosis. With the advanced possibilities of the post-processing of CT-data (segmentation, three-dimensional reconstruction), post-myelo-CT is an excellent method for the evaluation of osseous structures and the myelon in preoperative planning. (orig.) [Deutsch] Dysraphien gehen haeufig mit ausgepraegten ossaeren Veraenderungen der Wirbelsaeule wie Skoliose, Halbwirbelbildungen und Synostosen einher. Mit den verbesserten Moeglichkeiten der Datennachbearbeitung (Segmentierung, 3D-dimensionale Rekonstruktion) stellt die postmyelographische Computertomographie vor allem bei komplexen Fehlbildungen ein geeignetes Verfahren zur praeoperativen Beurteilung der ossaeren Strukturen der Wirbelsaeule und des Myelons dar. (orig.)

Integrated three-dimensional display of MR, CT, and PET images of the brain

International Nuclear Information System (INIS)

Levin, D.N.; Herrmann, A.; Chen, G.T.Y.

1988-01-01

MR, CT, and PET studies depict complementary aspects of brain anatomy and function. The authors' own image-processing software and a Pixar image computer were used to create three-dimensional models of brain soft tissues from MR images, of the skull and calcifications from CT scans, and of brain metabolism from PET images. An image correlation program, based on surface fitting, was used for retrospective registration and merging of these three-dimensional models. The results are demonstrated in a video clip showing how the operator may rotate and perform electronic surgery on the integrated, multimodality three-dimensional model of each patient's brain

Thymic epithelial tumors: Comparison of CT and MR imaging findings of low-risk thymomas, high-risk thymomas, and thymic carcinomas

International Nuclear Information System (INIS)

Sadohara, Junko; Fujimoto, Kiminori; Mueller, Nestor L.; Kato, Seiya; Takamori, Shinzo; Ohkuma, Kazuaki; Terasaki, Hiroshi; Hayabuchi, Naofumi

2006-01-01

Objective: To assess the CT and magnetic resonance (MR) imaging findings of thymic epithelial tumors classified according to the current World Health Organization (WHO) histologic classification and to determine useful findings in differentiating the main subtypes. Materials and methods: Sixty patients with thymic epithelial tumor who underwent both CT and MR imaging were reviewed retrospectively. All cases were classified according to the 2004 WHO classification. The following findings were assessed in each case on both CT and MRI: size of tumor, contour, perimeter of capsule; homogeneity, presence of septum, hemorrhage, necrotic or cystic component within tumor; presence of mediastinal lymphadenopathy, pleural effusion, and great vessel invasion. These imaging characteristics of 30 low-risk thymomas (4 type A, 12 type AB, and 14 type B1), 18 high-risk thymomas (11 type B2 and seven type B3), and 12 thymic carcinomas on CT and MR imaging were compared using the chi-square test. Comparison between CT and MR findings was performed by using McNemar test. Results: On both CT and MR imaging, thymic carcinomas were more likely to have irregular contours (P < .001), necrotic or cystic component (P < .05), heterogeneous contrast-enhancement (P < .05), lymphadenopathy (P < .0001), and great vessel invasion (P < .001) than low-risk and high-risk thymomas. On MR imaging, the findings of almost complete capsule, septum, and homogenous enhancement were more commonly seen in low-risk thymomas than high-risk thymomas and thymic carcinomas (P < .05). MR imaging was superior to CT in the depiction of capsule, septum, or hemorrhage within tumor (all comparison, P < .05). Conclusion: The presence of irregular contour, necrotic or cystic component, heterogeneous enhancement, lymphadenopathy, and great vessel invasion on CT or MR imaging are strongly suggestive of thymic carcinomas. On MR imaging, the findings of contour, capsule, septum, and homogenous enhancement are helpful in

Magnetic resonance maging of epidural and subdural spinal hematomas; Magnetresonanztomographie bei epiduralen und subduralen spinalen Haematomen

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Felber, S. [Universitaetskliniken Innsbruck (Austria). Klinik fuer Neurologie]|[Universitaetskliniken Innsbruck (Austria). Inst. fuer Magnetresonanz]|[Universitaetskliniken des Saarlandes, Homburg/Saar (Germany). Inst. fuer Neuroradiologie; Langmaier, J. [Universitaetskliniken Innsbruck (Austria). Klinik fuer Neurochirurgie; Judmaier, W. [Universitaetskliniken Innsbruck (Austria). Inst. fuer Magnetresonanz]|[Universitaetskliniken Innsbruck (Austria). Klinik fuer Radiologie; Dessl, A. [Universitaetskliniken Innsbruck (Austria). Klinik fuer Radiologie; Ortler, M. [Universitaetskliniken Innsbruck (Austria). Klinik fuer Neurochirurgie; Birbamer, G. [Universitaetskliniken Innsbruck (Austria). Klinik fuer Neurologie]|[Universitaetskliniken Innsbruck (Austria). Inst. fuer Magnetresonanz; Piepgras, U. [Universitaetskliniken des Saarlandes, Homburg/Saar (Germany). Inst. fuer Neuroradiologie

1994-11-01

Epidural und subdural spinal hematomas were previously diagnosed by myelography and computed tomography (CT). Recent reports indicate that noninvasive detection is possible with magnetic resonance imaging. We report on nine patients who were investigated by magnetic resonance imaging (MR) prior to surgery for epidural and subdural spinal hematoma. The MR examinations were performed on 1.5-T and 1-T units. We used surface coils and employed T1-, PD- and T2-weighted spin echo sequences and a T2*-weighted gradient echo sequence. CT was available in four patients and myelography in two patients. Surgical correlation was available in all patients. The hematomas were located in the cervical spine (n=2), thoracic spine (n=6) and lumbar spine (n=2). They were epidural in five patients and subdural in four. Blinded reading correctly indentified all five epidural hematomas and three of the subdural hematomas; one subdural hematoma was misjudged as epidural. Peracute hematomas (<24 h) in three patients appeared isointense or slightly hyperintense on T1-weighted images and had mixed signal intensity on T2- and T2*-weighted images. Acute hematomas (1-3 days) in four patients were also isointense on T1-weighted images but were more hypointense on T2- and T2*-weighted images. Chronic heamatomas in two patients (7 days and 14 days) were hyperintense on all sequences. Differentiation between epi- and subdural hematomas required transverse T2*-weighted gradient echo sequences. Our results underline that MRI at 1 and 1.5 T is capable of identifying epidural and subdural spinal hematoma in the acute and peracute stage. MRI is superior to CT and myelography for the delineation of the craniocaudal extension in epidural and subdural spinal hematomas and should be the primary preoperative diagnostic method. (orig.) [Deutsch] Epidurale und subdurale spinale Haematome sind neurochirurgische Notfaelle, deren Diagnose bisher vorwiegend mittels Myelographie und Computertomographie gestellt

Evaluation of whole-body MR to CT deformable image registration

NARCIS (Netherlands)

Akbarzadeh, A.; Gutierrez, D.; Baskin, A.; Ay, M. R.; Ahmadian, A.; Alam, N. Riahi; Loevblad, K. O.; Zaidi, H.

2013-01-01

Multimodality image registration plays a crucial role in various clinical and research applications. The aim of this study is to present an optimized MR to CT whole-body deformable image registration algorithm and its validation using clinical studies. A 3D intermodality registration technique based

Postoperative MR arthography of the shoulder joint; MR-Arthographie des Schultergelenks im postoperativen Patientenkollektiv

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Rand, T. [Einrichtung fuer Magnetresonanz, Ludwig Boltzmann-Inst. fuer Radiologische Tumordiagnostik, Univ. Wien (Austria); Trattnig, S. [Einrichtung fuer Magnetresonanz, Ludwig Boltzmann-Inst. fuer Radiologische Tumordiagnostik, Univ. Wien (Austria); Breitenseher, M. [Einrichtung fuer Magnetresonanz, Ludwig Boltzmann-Inst. fuer Radiologische Tumordiagnostik, Univ. Wien (Austria); Freilinger, W. [Orthopaedisches Krankenhaus Speising (Austria); Cochole, M. [Orthopaedische Abt., Allgemein Oeffentliches Krankenhaus Amstetten (Austria); Imhof, H. [Einrichtung fuer Magnetresonanz, Ludwig Boltzmann-Inst. fuer Radiologische Tumordiagnostik, Univ. Wien (Austria)

1996-12-01

Indications of MR arthrography were analyzed in this prospective study. The aim was to evaluate possible advantages over conventional MRI, establish diagnostic criteria and to analyze its meaning further for the therapeutic management of postoperative patients. MR arthrography was performed in eight patients who had undergone surgical repair of rotator cuff lesions (modified Neer acromioplasty) and in six patients who had undergone arthroscopic therapy of recurrent unidirectional dislocation of the shoulder by combined arthroscopic intra- and extracapsular repair. MR investigations were performed before and after application of a contrast solution (2 mmol Gd-DTPA). All patients suffered from chronic postoperative pain. In patients with rotator cuff lesions, a partial tear could be verified in one patient and excluded in all others. In patients after arthroscopic therapy by combined intra- and extracapsular repair, a radiologically patulous-appearing capsule correlated with clinically recurrent dislocations. In all other patients diagnostic criteria, such as distribution of the intra-articular contrast solution, proliferation of scar tissue, nodular appearance of the glenohumeral ligaments and capsule thickness, correlated with a regular postoperative status. MR arthrography of the shoulder represents a promising method in the evaluation of the postoperative shoulder. It might further improve the evaluation of reactive capsule alterations, scar tissue proliferation, and the labroligamentous complex, as well as the ability to differentiate partial and complete rerupture from degenerative changes of the rotator cuff. (orig.) [Deutsch] In einer prospektiven Studie sollten die Einsatzmoeglichkeiten der MR-Arthrographie am operierten Schultergelenk erfasst werden. Ziel der Studie war einerseits eine gegenueber der konventionellen MR-Untersuchung verbesserten Diagnosestellung und andererseits die Erstellung von fuer die Rezidivdiagnostik relevanten Diagnosekriterien

Comparison of the performance of {sup 18}F-FP-CIT brain PET/MR and simultaneous PET/CT: A preliminary study

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Kwon, Sang Don; Chun, Kyung Ah [Dept. of Nuclear Medicine, Yeungnam University Hospital, Daegu (Korea, Republic of)

2016-09-15

{sup 18}F-FP-CIT [{sup 1'}8F-fluorinated N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) nortropane] has been well established and used for the differential diagnosis of atypical parkinsonian disorders. Recently, combined positron emission tomography (PET)/magnetic resonance (MR) was proposed as a viable alternative to PET/computed tomography (CT). The aim of this study was to compare the performances of conventional {sup 18}F-FP-CIT brain PET/CT and simultaneous PET/MR by visual inspection and quantitative analysis. Fifteen consecutive patients clinically suspected of having Parkinson's disease were recruited for the study.{sup 18}F-FP-CIT PET was performed during PET/CT and PET/MR. PET/CT image acquisition was started 90 min after intravenous injection of {sup 18}F-FP-CIT and then PET/MR images were acquired. Dopamine transporter (DAT) density in bilateral striatal subregions was assessed visually. Quantitative analyses were performed on bilateral striatal volumes of interest (VOIs) using average standardized uptake values (SUVmeans). Intraclass correlation coefficients (ICCs) and their 95 % confidence intervals (CIs) were assessed to compare PET/CT and PET/MR data. Bland-Altman plots were drawn to perform method-comparisons. All subjects showed a preferential decrease in DAT binding in the posterior putamen (PP), with relative sparing of the ventral putamen (VP). Bilateral striatal subregional binding ratio (BR) determined PET/CT and PET/MR demonstrated close interequipment correspondence (BRright caudate - ICC, 0.944; 95 % CI, 0.835-0.981, BRleft caudate - ICC, 0.917; 95 % CI, 0.753-0.972, BRright putamen - ICC, 0.976; 95 % CI, 0.929-0.992 and BRleft putamen - ICC, 0.970; 95 % CI, 0.911-0.990, respectively), and Bland-Altman plots showed interequipment agreement between the two modalities. It is known that MR provides more information about anatomical changes associated with brain diseases and to enable the anatomical allocations of

Detection and quantification of focal uptake in head and neck tumours: {sup 18}F-FDG PET/MR versus PET/CT

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Varoquaux, Arthur; Rager, Olivier; Ratib, Osman; Becker, Christoph D.; Zaidi, Habib; Becker, Minerva [Geneva University Hospital, Department of Imaging, Divisions of Radiology and Nuclear Medicine, Geneva 14 (Switzerland); Poncet, Antoine [Geneva University Hospital, Center for Clinical Research, Geneva (Switzerland); Delattre, Benedicte M.A. [Geneva University Hospital, Department of Imaging, Divisions of Radiology and Nuclear Medicine, Geneva 14 (Switzerland); Philips Healthcare AG, Nuclear Medicine Division, Gland (Switzerland); Dulguerov, Pavel; Dulguerov, Nicolas [Geneva University Hospital, Clinic of Otorhinolaryngology Head and Neck Surgery, Geneva (Switzerland)

2014-03-15

Our objectives were to assess the quality of PET images and coregistered anatomic images obtained with PET/MR, to evaluate the detection of focal uptake and SUV, and to compare these findings with those of PET/CT in patients with head and neck tumours. The study group comprised 32 consecutive patients with malignant head and neck tumours who underwent whole-body {sup 18}F-FDG PET/MR and PET/CT. PET images were reconstructed using the attenuation correction sequence for PET/MR and CT for PET/CT. Two experienced observers evaluated the anonymized data. They evaluated image and fusion quality, lesion conspicuity, anatomic location, number and size of categorized (benign versus assumed malignant) lesions with focal uptake. Region of interest (ROI) analysis was performed to determine SUVs of lesions and organs for both modalities. Statistical analysis considered data clustering due to multiple lesions per patient. PET/MR coregistration and image fusion was feasible in all patients. The analysis included 66 malignant lesions (tumours, metastatic lymph nodes and distant metastases), 136 benign lesions and 470 organ ROIs. There was no statistically significant difference between PET/MR and PET/CT regarding rating scores for image quality, fusion quality, lesion conspicuity or anatomic location, number of detected lesions and number of patients with and without malignant lesions. A high correlation was observed for SUV{sub mean} and SUV{sub max} measured on PET/MR and PET/CT for malignant lesions, benign lesions and organs (ρ = 0.787 to 0.877, p < 0.001). SUV{sub mean} and SUV{sub max} measured on PET/MR were significantly lower than on PET/CT for malignant tumours, metastatic neck nodes, benign lesions, bone marrow, and liver (p < 0.05). The main factor affecting the difference between SUVs in malignant lesions was tumour size (p < 0.01). In patients with head and neck tumours, PET/MR showed equivalent performance to PET/CT in terms of qualitative results. Comparison of

Chronic tears of the posterior tibial tendon: A correlative study of CT, MR imaging, and surgical exploration

International Nuclear Information System (INIS)

Rosenberg, Z.S.; Cheung, Y.; Jahss, M.; Noto, A.M.; Norman, A.; Leeds, N.E.

1987-01-01

Fifty-two cases with clinically suspected chronic tears of the posterior tibial tendon were studied with either CT (22 cases), MR imaging (nine cases), or both modalities (21 cases). Subsequent surgical exploration was performed in 22 of the cases (43%). Three radiologic patterns of tendon abnormalities were recognized: (1) hypertrophied, heterogeneous tendon; (2) attenuated tendon; and (3) tendon gap. Both type 1 and type 2 patterns correlated surgically with partial tendon ruptures, and type 3 correlated with complete tendon rupture. While both CT and MR imaging demonstrated excellent correlation with surgical findings, MR was superior in detecting early partial ruptures, longitudinal splits, and synovial fluid. CT was superior in evaluating associated bony abnormalities such as periostitis and subtalar dislocations

CT and MR evaluation of migrational disorders of the brain. Pt. 1. Lissencephaly and pachygyria

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Byrd, S E; Osborn, R E; Bohan, T P; Naidich, T P

1989-03-01

The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria-pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (part I) deals with our patients with lissencephaly and pachygyria. It emphasizes their characteristic CT and MR findings along with their clinical presentation and course. These patients presented with one or a combination of the following symptoms, hypotonia, seizures, failure to thrive, microcephaly and occasionally hydrocephalus. These two groups of migrational disorders have abnormalities affecting the gyral-sulcal pattern of the cortex and gray-white matter distribution of the brain. MR provided better delineation of these disorders than CT. Because some forms of the migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling.

Aortitis with antiphospholipid antibodies: CT and MR findings

International Nuclear Information System (INIS)

Seror, O.; Dordea, M.; Ghenassia, C.; Coderc, E.; Sellier, N.; Fain, O.

1998-01-01

Two cases of aortitis associated with the presence of antiphospholipid antibodies (APAs) are reported. Only CT and MR imaging were able to show these unusual form of aortitis preferentially affecting the outer aortic tunics. We conclude that aortitis could be a new manifestation of primary antiphospholipid syndrome (APS) and the initial pathological process before the development of aortic thrombosis, reported as a classical complication of APS. (orig.) (orig.)

CT and MR angiographic findings in dissection of cervical vessels

International Nuclear Information System (INIS)

Link, J.; Brinkmann, G.; Heuser, K.; Heller, M.

1996-01-01

Purpose: To determine the usefulness of CT angiography (CTA) and MR angiography (MRA) for evaluation of dissection in cervical vessels. Material and methods: Dissection of cervical vessels was revealed by conventional angiography in 4 patients (two female, two male) of 30-62 years of age. Dissection was located in the carotid artery (n=3) and in the vertebral artery (n=1). In two patients CTA and in two patients MRA was performed. Results: Diagnosis of dissection was possible by CTA (internal carotid artery: n=2) and by MRA (internal carotid artery and vertebral artery). Imaging of the dissection membrane of the vessel wall was possible in one case with MRA. Conclusion: CT and MR angiography was successful for detection of typical morphology of dissection in all cases. If results in a greater number can be obtained it seems to be conceivable that both methods can be used in primary diagnosis. (orig.) [de

Comparison of MR versus CT myelography and plain CT in the diagnosis of nerve compression in acute low-back pain patients

International Nuclear Information System (INIS)

Thornbury, J.R.; Fryback, D.G.; Turski, P.A.; Javid, M.; McDonald, J.V.; Beinlich, B.R.

1991-01-01

This paper reports on how to determine if MR could replace CT-myelography or plain CT in the diagnosis of disk-caused nerve compression in patients with acute low back pain. Ninety-five outpatients were recruited from surgical and nonsurgical clinics. Each patient underwent MR (n = 95) and either CT-myelography (n = 63) or plain Ct (n = 32). Patients were followed up for 6-12 months. Fifty-six patients underwent surgical intervention, while 39 patients were treated conservatively. Retrospective blinded readings were done by using forced choice diagnoses and probability estimates. An expert panel (neurosurgeon and neurologist) determined the true diagnosis and probability of nerve compression in each case. Diagnosis was based on all record information including surgical findings (but excluding imaging results to reduce incorporation bias). Receiver operating characteristic (ROC) analysis was performed based on the blinded reading results and panel-determined true diagnoses. Subgroup analysis also will be presented

Deep embedding convolutional neural network for synthesizing CT image from T1-Weighted MR image.

Science.gov (United States)

Xiang, Lei; Wang, Qian; Nie, Dong; Zhang, Lichi; Jin, Xiyao; Qiao, Yu; Shen, Dinggang

2018-07-01

Recently, more and more attention is drawn to the field of medical image synthesis across modalities. Among them, the synthesis of computed tomography (CT) image from T1-weighted magnetic resonance (MR) image is of great importance, although the mapping between them is highly complex due to large gaps of appearances of the two modalities. In this work, we aim to tackle this MR-to-CT synthesis task by a novel deep embedding convolutional neural network (DECNN). Specifically, we generate the feature maps from MR images, and then transform these feature maps forward through convolutional layers in the network. We can further compute a tentative CT synthesis from the midway of the flow of feature maps, and then embed this tentative CT synthesis result back to the feature maps. This embedding operation results in better feature maps, which are further transformed forward in DECNN. After repeating this embedding procedure for several times in the network, we can eventually synthesize a final CT image in the end of the DECNN. We have validated our proposed method on both brain and prostate imaging datasets, by also comparing with the state-of-the-art methods. Experimental results suggest that our DECNN (with repeated embedding operations) demonstrates its superior performances, in terms of both the perceptive quality of the synthesized CT image and the run-time cost for synthesizing a CT image. Copyright © 2018. Published by Elsevier B.V.

Osseous abnormalities and CT findings in stueve-wiedemann-syndrome (SWS); Ossaere Manifestationen und CT-Befunde bei der seltenen Skelettdysplasie Stueve-Wiedemann (SWS)

Energy Technology Data Exchange (ETDEWEB)

Langer, R. [UAE University, Dept. of Radiology, Al Ain (United Arab Emirates); Al-Gazali, L. [UAE University, Dept. of Paediatrics (United Arab Emirates); Haas, D. [FMHS - UAE Univ. and Tawam Hospital - Dept. of Radiology (United Arab Emirates); Raupp, P.; Varady, E. [Dept. of Paediatrics Al Ain (United Arab Emirates)

2004-02-01

Purpose: analysis of typical conventional radiological and CT findings in our group of patients with the rare skeletal dysplasia Stueve-Wiedemann-Syndrome (SWS) and comparison with published data. Materials and methods: in 16 newborns with clinically dysmorphic features, dwarfism, and bowed limbs, radiographs of the chest and skeleton were obtained for classification of the underlying skeletal dysplasia. For the first time, computed tomography was performed for further investigation of midface hypoplasia. The early diagnosis of SWS could be made by correlation of the radiological and clinical findings. For evaluation of progression, follow-up radiological examinations of the skeleton were performed in four children surviving infancy. Results: clinically, the newborns with SWS showed dwarfisms, midface hypoplasia, bowed extremities with contractures and had severe problems with respiration, feeding, and swallowing as well as episodes of hyperthermia. Skeletal radiographs revealed bowing of the long tubular bones, most pronounced at the lower extremities. Additional findings were internal triangular cortical diaphyseal thickening at the concave side of the bowing, wide metaphyses with abnormal trabecular pattern and radiolucencies. Four patients survived infancy. Clinically, they suffered from recurrent aspiration pneumonia and recurrent episodes of hyperthermia as well as form cutaneous and mucosal infections. The follow-up radiographs showed progressive bowing of the long tubular bones as well as progressive metaphyseal decalcification. Conclusions: skeletal abnormalities in SWS are so characteristic that an early post partum diagnosis can be made. However, a close cooperation between radiologists, clinicians, and geneticists is required for correlation of clinical and radiological findings. The few cases that survive infancy have progressing orthopaedic problems. (orig.) [German] Ziel: Die typischen radiologischen und CT-Befunde beim kongenitalen Stueve

Indirect MR arthrography in the evaluation of tears of the glenoid labrum; Indirekte MR-Arthrographie in der Diagnostik von Laesionen des Labrum glenoidale

Energy Technology Data Exchange (ETDEWEB)

Sommer, T.; Vahlensieck, M.; Lutterbey, G.; Pauleit, D.; Kreft, B.; Keller, E.; Schild, H. [Radiologische Universitaetsklinik Bonn (Germany); Wallny, T. [Orthopaedische Universitaetsklinik Bonn (Germany); Steuer, K.; Golombek, V. [Klinik fuer Unfallchirurgie, Univ. Bonn (Germany)

1997-07-01

Purpose: It has been shown that intravenous administration of contrast media produces an MR arthrographic effect without the need for intraarticular injection. This is the first study evaluating this new technique of indirect MR arthrography in the diagnosis of glenoid labrum tears. Methods: 28 patients with clinically suspected labral injuries were prospectively investigated (1.5 Tesla, flexible surface coil). A plain MR examination of the shoulder (transverse and oblique-coronal orientation, T{sub 1}-weighted spin- [T{sub E}/T{sub R} 15/675], proton density- and T{sub 2}*-weighted gradient echo [T{sub E}/T{sub R}/Flip 14,32/600/30 ] sequences) and indirect MR arthrography (transverse and oblique-coronal orientation, fat-suppressed T{sub 1}-weighted spin-echo sequences [T{sub E}/T{sub R} 15/675], intravenous injection of gadopentetate dimeglumine [0.1 mmol/kg], followed by 10-15 min of joint movement) were performed. Results were confirmed by arthroscopy and/or open surgery. Results: Indirect MR arthrography significantly improved delineation of the glenoid labrum and hyaline cartilage (p<0.05). Sensitivity and specificity of indirect MR arthrography in the diagnosis of labral injuries were 90% and 89%, compared to 79% and 67% of the native MR examination. Conclusion: Indirect MR arthrography is a promising non-invasive technique in the evaluation of the glenoid labrum. (orig.) [Deutsch] Ziel: In frueheren Studien wurde gezeigt, dass die intravenoese Injektion gadoliniumhaltiger Kontrastmittel zur Signalintensitaetssteigerung im Gelenkkavum fuehrt. In dieser Studie wurde erstmals diese Technik der indirekten MR-Arthrographie am Schultergelenk in der Diagnostik von Labrumlaesionen evaluiert. Methode: 28 Patienten mit klinischem Verdacht auf eine Verletzung des Labrum glenoidale und/oder der Rotatorenmanschette wurden prospektiv nach folgendem Protokoll an einem 1,5-Tesla-System mit einer Oberflaechen-Ringspule untersucht: 1. Native MR-Standard-Untersuchung mit

Gadolinium-enhanced T{sub 1}-weighted MR urography versus T{sub 2}-weighted (HASTE) MR urography in children; Kontrastangehobene T{sub 1}-gewichtete MR-Urographie versus T{sub 2}-gewichtete (HASTE) MR-Urographie im Kindesalter

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Staatz, G.; Nolte-Ernsting, C.C.A.; Haage, P.; Tacke, J.; Guenther, R.W. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Rohrmann, D. [Technische Hochschule Aachen (Germany). Urologische Klinik; Stollbrink, C. [Technische Hochschule Aachen (Germany). Kinderklinik

2001-11-01

Purpose: To evaluate gadolinium-enhanced T{sub 1}-weighted excretory MR urography (EMRU) versus T{sub 2}-weighted (HASTE) MR urography in children with upper urinary tract abnormalities. Patients and Methods: In a prospective study 63 children, aged from 3 weeks to 15 years, underwent MR urography in a 1.5-T scanner. Before and after an intravenous injection of 0.05 mg/kg body weight of furosemide, respiratory-triggered HASTE images were obtained for T{sub 2}-weighted MR urography. EMRU was performed subsequent to i.v. gadolinium injection with respiratory-gated, coronal 3D-gradient-echo sequences. Results: Compared to T{sub 2}-weighted (HASTE) MR urography, gadolinium-enhanced MR urography revealed a superior diagnostic accuracy in non-dilated collecting systems (horseshoe kidneys, ectopic kidneys, duplex systems, single ectopic ureters, ureteroceles). EMRU and T{sub 2}-weighted (HASTE) MRU turned out to be equivalent in the assessment of obstructed but normal functioning upper urinary tracts (UPJ obstructions, megaureters). Non-functioning dilated collecting systems and multicystic dysplastic kidneys were best visualized with use of T{sub 2}-weighted (HASTE) MR urography. Conclusion: Respiratory-gated gadolinium-enhanced T{sub 1}-weighted MRU allows accurate evaluation of most upper urinary tract abnormalities. T{sub 2}-weighted (HASTE) MRU complements GMRU in the evaluation of non-functioning renal units and cystic disease of the kidneys. (orig.) [German] Ziel: Vergleich der kontrastangehobenen T{sub 1}-gewichteten MR-Urographie mit der T{sub 2}-gewichteten (HASTE) MR-Urographie bei Kindern mit Anomalien des oberen Harntraktes. Methoden: In einer prospektiven Studie wurde bei 63 Kindern (3 Wo. - 15J.) eine MR-Urographie (MRU) in einem 1,5-Tesla-Magneten durchgefuehrt. Die T{sub 2}-gewichtete MRU erfolgte vor und nach intravenoeser Injektion von 0,05 mg/kg KG Furosemid mit atemgetriggerten HASTE-Sequenzen. Fuer die T{sub 1}-gewichtete MRU wurden nach

Pathologic contrast enhancement of cerebral lesions: A comparative study using stereotactic CT, stereotactic MR imaging, and stereotactic biopsy

International Nuclear Information System (INIS)

Earnest, F. IV; Kelly, P.J.; Scheithauer, B.; Kall, B.; Cascino, T.L.; Ehman, R.L.; Forbes, G.

1986-01-01

The author compared the pattern and degree of Gd-DTPA dimeglumine contrast enhancement demonstrated on stereotactic MR images with that seen on stereotactic CT images obtained after conventional iodinated contrast agent enhancement and with histopathologic findings on sequential stereotactic brain biopsies. Stereotactic biopsies of the areas that enhanced on CT or MR imaging revealed tumor tissue with neovascularity. Tumor tissue with no or mild neovascularity did not enhance with contrast agent administration. Isolated tumor cells were frequently found beyond the margins of some primary brain neoplasms defined by contrast agent-enhanced MR imaging and CT. The histopathologic findings associated with pathologic contrast agent enhancement are presented

Interventional MR-Mammography: manipulator-assisted large core biopsy and interstitial laser therapy of tumors of the female breast; Interventionelle MR-Mammographie: Manipulatorgestuetzte Biopsie und interstitielle Lasertherapie von Tumoren der weiblichen Brust

Energy Technology Data Exchange (ETDEWEB)

Pfleiderer, S.O.R.; Reichenbach, J.R.; Wurdinger, S.; Marx, C.; Freesmeyer, M.G.; Kaiser, W.A. [Inst. fuer Diagnostische und Interventionelle Radiologie, Friedrich-Schiller-Univ. Jena (Germany); Vagner, J.; Fischer, H. [Inst. fuer Medizintechnik und Biophysik, Forschungszentrum Karlsruhe (Germany); Schneider, A. [Klinik fuer Frauenheilkunde, Friedrich-Schiller-Univ. Jena (Germany)

2003-07-01

histopathologische Befund der Brustbiopsie am Operationspraeparat bestaetigt. Bei 3 weiteren Patientinnen wurden ein tubulaeres und ein duktales Karzinom bioptisch nicht erkannt und ein invasives Karzinom unterschaetzt. 8 Patientinnen mit benignen Befunden in der Biopsie befinden sich noch in der Nachbeobachtungsphase. Auf den subtrahierten Phasenbildern war die Erhitzungszone waehrend der ILT gut sichtbar. Ernsthafte Komplikationen traten weder bei der Biopsie noch bei der ILT auf. MR-gestuetzte Brustbiopsien sind unter Verwendung des Manipulatorsystems innerhalb eines 1,5-Tesla-Ganzkoerperkernspintomographen durchfuehrbar. Zur Therapieueberwachung der ILT im Tumor ist eine GRE geeignet. Weiterfuehrende Studien zur Beurteilung der Praezision des Manipulatorsystems und der Effektivitaet der ILT in der Behandlung von Mammalaesionen sind notwendig. (orig.)

Do carotid MR surface coils affect PET quantification in PET/MR imaging?

International Nuclear Information System (INIS)

Willemink, Martin J; Eldib, Mootaz; Leiner, Tim; Fayad, Zahi A; Mani, Venkatesh

2015-01-01

To evaluate the effect of surface coils for carotid MR imaging on PET quantification in a clinical simultaneous whole-body PET/MR scanner. A cylindrical phantom was filled with a homogeneous 2L water-FDG mixture at a starting dose of 301.2MBq. Clinical PET/MR and PET/CT systems were used to acquire PET-data without a coil (reference standard) and with two carotid MRI coils (Siemens Special Purpose 8-Channel and Machnet 4-Channel Phased Array). PET-signal attenuation was evaluated with Osirix using 51 (PET/MR) and 37 (PET/CT) circular ROIs. Mean and maximum standardized uptake values (SUVs) were quantified for each ROI. Furthermore, SUVs of PET/MR and PET/CT were compared. For validation, a patient was scanned with an injected dose of 407.7MBq on both a PET/CT and a PET/MR system without a coil and with both coils. PET/MR underestimations were -2.2% (Siemens) and -7.8% (Machnet) for SUVmean, and -1.2% (Siemens) and -3.3% (Machnet) for SUVmax, respectively. For PET/CT, underestimations were -1.3% (Siemens) and -1.4% (Machnet) for SUVmean and -0.5% (both Siemens and Machnet) for SUVmax, respectively using no coil data as reference. Except for PET/CT SUVmax values all differences were significant. SUVs differed significantly between PET/MR and PET/CT with SUVmean values of 0.51-0.55 for PET/MR and 0.68-0.69 for PET/CT, respectively. The patient examination showed that median SUVmean values measured in the carotid arteries decreased from 0.97 without a coil to 0.96 (Siemens) and 0.88 (Machnet). Carotid surface coils do affect attenuation correction in both PET/MR and PET/CT imaging. Furthermore, SUVs differed significantly between PET/MR and PET/CT.

Inter-slice bidirectional registration-based segmentation of the prostate gland in MR and CT image sequences

Energy Technology Data Exchange (ETDEWEB)

Khalvati, Farzad, E-mail: farzad.khalvati@uwaterloo.ca; Tizhoosh, Hamid R. [Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Salmanpour, Aryan; Rahnamayan, Shahryar [Department of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario L1H 7K4 (Canada); Rodrigues, George [Department of Radiation Oncology, London Regional Cancer Program, London, Ontario N6C 2R6, Canada and Department of Epidemiology/Biostatistics, University of Western Ontario, London, Ontario N6A 3K7 (Canada)

2013-12-15

Purpose: Accurate segmentation and volume estimation of the prostate gland in magnetic resonance (MR) and computed tomography (CT) images are necessary steps in diagnosis, treatment, and monitoring of prostate cancer. This paper presents an algorithm for the prostate gland volume estimation based on the semiautomated segmentation of individual slices in T2-weighted MR and CT image sequences. Methods: The proposedInter-Slice Bidirectional Registration-based Segmentation (iBRS) algorithm relies on interslice image registration of volume data to segment the prostate gland without the use of an anatomical atlas. It requires the user to mark only three slices in a given volume dataset, i.e., the first, middle, and last slices. Next, the proposed algorithm uses a registration algorithm to autosegment the remaining slices. We conducted comprehensive experiments to measure the performance of the proposed algorithm using three registration methods (i.e., rigid, affine, and nonrigid techniques). Results: The results with the proposed technique were compared with manual marking using prostate MR and CT images from 117 patients. Manual marking was performed by an expert user for all 117 patients. The median accuracies for individual slices measured using the Dice similarity coefficient (DSC) were 92% and 91% for MR and CT images, respectively. The iBRS algorithm was also evaluated regarding user variability, which confirmed that the algorithm was robust to interuser variability when marking the prostate gland. Conclusions: The proposed algorithm exploits the interslice data redundancy of the images in a volume dataset of MR and CT images and eliminates the need for an atlas, minimizing the computational cost while producing highly accurate results which are robust to interuser variability.

Inter-slice bidirectional registration-based segmentation of the prostate gland in MR and CT image sequences

International Nuclear Information System (INIS)

Khalvati, Farzad; Tizhoosh, Hamid R.; Salmanpour, Aryan; Rahnamayan, Shahryar; Rodrigues, George

2013-01-01

Purpose: Accurate segmentation and volume estimation of the prostate gland in magnetic resonance (MR) and computed tomography (CT) images are necessary steps in diagnosis, treatment, and monitoring of prostate cancer. This paper presents an algorithm for the prostate gland volume estimation based on the semiautomated segmentation of individual slices in T2-weighted MR and CT image sequences. Methods: The proposedInter-Slice Bidirectional Registration-based Segmentation (iBRS) algorithm relies on interslice image registration of volume data to segment the prostate gland without the use of an anatomical atlas. It requires the user to mark only three slices in a given volume dataset, i.e., the first, middle, and last slices. Next, the proposed algorithm uses a registration algorithm to autosegment the remaining slices. We conducted comprehensive experiments to measure the performance of the proposed algorithm using three registration methods (i.e., rigid, affine, and nonrigid techniques). Results: The results with the proposed technique were compared with manual marking using prostate MR and CT images from 117 patients. Manual marking was performed by an expert user for all 117 patients. The median accuracies for individual slices measured using the Dice similarity coefficient (DSC) were 92% and 91% for MR and CT images, respectively. The iBRS algorithm was also evaluated regarding user variability, which confirmed that the algorithm was robust to interuser variability when marking the prostate gland. Conclusions: The proposed algorithm exploits the interslice data redundancy of the images in a volume dataset of MR and CT images and eliminates the need for an atlas, minimizing the computational cost while producing highly accurate results which are robust to interuser variability

SU-E-T-504: Usefulness of CT-MR Fusion in Radiotherapy Planning for Prostate Cancer Patient with Bilateral Hip Replacements

Energy Technology Data Exchange (ETDEWEB)

He, R.; Giri, Shankar [University of Mississippi Med. Center, Jackson, MS (United States); VA Medical Center at Jackson, Mississippi (United States); Kumar, P. [VA Medical Center at Jackson, Mississippi (United States); Hu, Y.; Suggs, J.; Yang, C. [University of Mississippi Med. Center, Jackson, MS (United States)

2014-06-01

Purpose: Target localization of prostate for Intensity Modulated Radiation Therapy (IMRT) in patients with bilateral hip replacements is difficult due to artifacts in Computed Tomography (CT) images generated from the prostheses high Z materials. In this study, Magnetic Resonance (MR) images fused with CT images are tested as a solution. Methods: CT images of 2.5 mm slice thickness were acquired on a GE Lightspeed scanner with a flat-topped couch for a prostate cancer patient with bilateral hip replacements. T2 weighted images of 5 mm separation were acquired on a MR Scanner. After the MR-CT registration on a radiotherapy treatment planning system (Eclipse, Varian), the target volumes were defined by the radiation oncologists on MR images and then transferred to CT images for planning and dose calculation. The CT Hounsfield Units (HU) was reassigned to zero (as water) for artifacts. The Varian flat panel treatment couch was modeled for dose calculation accuracy with heterogeneity correction. A Volume Matrix Arc Therapy (VMAT) and a seven-field IMRT plans were generated, each avoiding any beam transversing the prostheses; the two plans were compared. The superior VMAT plan was used for treating the patient. In-vivo dosimetry was performed using MOSFET (Best Canada) placed in a surgical tube inserted into the patient rectum during therapy. The measured dose was compared with planned dose for MOSFET location. Results: The registration of MR-CT images and the agreement of target volumes were confirmed by three physicians. VMAT plan was deemed superior to IMRT based on dose to critical nearby structures and overall conformality of target dosing. In-vivo measured dose compared with calculated dose was -4.5% which was likely due to attenuation of the surgical tube surrounding MOSFET. Conclusion: When artifacts are present on planning CT due to bilateral hip prostheses, MR-CT image fusion is a feasible solution for target delineation.

SU-E-T-504: Usefulness of CT-MR Fusion in Radiotherapy Planning for Prostate Cancer Patient with Bilateral Hip Replacements

International Nuclear Information System (INIS)

He, R.; Giri, Shankar; Kumar, P.; Hu, Y.; Suggs, J.; Yang, C.

2014-01-01

Purpose: Target localization of prostate for Intensity Modulated Radiation Therapy (IMRT) in patients with bilateral hip replacements is difficult due to artifacts in Computed Tomography (CT) images generated from the prostheses high Z materials. In this study, Magnetic Resonance (MR) images fused with CT images are tested as a solution. Methods: CT images of 2.5 mm slice thickness were acquired on a GE Lightspeed scanner with a flat-topped couch for a prostate cancer patient with bilateral hip replacements. T2 weighted images of 5 mm separation were acquired on a MR Scanner. After the MR-CT registration on a radiotherapy treatment planning system (Eclipse, Varian), the target volumes were defined by the radiation oncologists on MR images and then transferred to CT images for planning and dose calculation. The CT Hounsfield Units (HU) was reassigned to zero (as water) for artifacts. The Varian flat panel treatment couch was modeled for dose calculation accuracy with heterogeneity correction. A Volume Matrix Arc Therapy (VMAT) and a seven-field IMRT plans were generated, each avoiding any beam transversing the prostheses; the two plans were compared. The superior VMAT plan was used for treating the patient. In-vivo dosimetry was performed using MOSFET (Best Canada) placed in a surgical tube inserted into the patient rectum during therapy. The measured dose was compared with planned dose for MOSFET location. Results: The registration of MR-CT images and the agreement of target volumes were confirmed by three physicians. VMAT plan was deemed superior to IMRT based on dose to critical nearby structures and overall conformality of target dosing. In-vivo measured dose compared with calculated dose was -4.5% which was likely due to attenuation of the surgical tube surrounding MOSFET. Conclusion: When artifacts are present on planning CT due to bilateral hip prostheses, MR-CT image fusion is a feasible solution for target delineation

Aortitis with antiphospholipid antibodies: CT and MR findings

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Seror, O.; Dordea, M.; Ghenassia, C.; Coderc, E.; Sellier, N. [Department of Radiology, Centre Hospitalo-Universitaire Paris XIII, Bondy (France); Fain, O. [Department of Medicine, Centre Hospitalo-Universitaire Paris XIII, Bondy (France)

1998-10-01

Two cases of aortitis associated with the presence of antiphospholipid antibodies (APAs) are reported. Only CT and MR imaging were able to show these unusual form of aortitis preferentially affecting the outer aortic tunics. We conclude that aortitis could be a new manifestation of primary antiphospholipid syndrome (APS) and the initial pathological process before the development of aortic thrombosis, reported as a classical complication of APS. (orig.) (orig.) With 2 figs., 6 refs.

CT and MR imaging of the kidney and adrenal glands: MR imaging of the kidney and adrenal glands

International Nuclear Information System (INIS)

Lee, J.K.T.

1987-01-01

The normal anatomy of the kidney is clearly demonstrated with MR imaging. The renal cortex can be differentiated from the renal medulla; renal vessels can also be identified. MR imaging can differentiate cystic from solid lesions. The signal intensity of a renal cell carcinoma varies and overlaps with the signal intensities of renal neoplasms of other etiologies. MR imaging is superior to CT in distinguishing vascular from nonvascular structures. It can distinguish collateral vessels from lymph nodes and can disclose tumoral thrombi. MR imaging can also aid in the differentiation of acute rejection from acute tubular necrosis in renal transplant recipients. Both normal and abnormal adrenal glands can be seen on MR imaging. A normal adrenal gland has a signal intensity higher than or equal to that of muscle but lower than that of fat. T1-weighted images offer excellent antomic resolution; T2-weighted images provide additional information about internal characteristics of adrenal neoplasms. Preliminary data indicate that MR imaging is useful in distinguishing nonfunctioning adenomas from adrenal metastases. The role of MR imaging of the kidney and adrenal gland is discussed

Cerebral cavernous angioma. 16 cases. Aspects in CT and MR

International Nuclear Information System (INIS)

Pina, J.I.; Medrano, J.; Lasierra, R.; Benito, J.L. de; Feijoo, R.; Fernandez, J.A.; Villavieja, J.L.

1995-01-01

The cerebral cavernous angioma (CA) is included in the group of cerebral malformations that can not be detected angiographically. We present the retrospective study of 16 patients, diagnosed as having CA, comparing the data provided by CT and MR, as well as the contribution of cerebral angiography. (Author) 25 refs

Comparison of lesion detection and quantitation of tracer uptake between PET from a simultaneously acquiring whole-body PET/MR hybrid scanner and PET from PET/CT

International Nuclear Information System (INIS)

Wiesmueller, Marco; Schmidt, Daniela; Beck, Michael; Kuwert, Torsten; Gall, Carl C. von; Quick, Harald H.; Navalpakkam, Bharath; Lell, Michael M.; Uder, Michael; Ritt, Philipp

2013-01-01

PET/MR hybrid scanners have recently been introduced, but not yet validated. The aim of this study was to compare the PET components of a PET/CT hybrid system and of a simultaneous whole-body PET/MR hybrid system with regard to reproducibility of lesion detection and quantitation of tracer uptake. A total of 46 patients underwent a whole-body PET/CT scan 1 h after injection and an average of 88 min later a second scan using a hybrid PET/MR system. The radioactive tracers used were 18 F-deoxyglucose (FDG), 18 F-ethylcholine (FEC) and 68 Ga-DOTATATE (Ga-DOTATATE). The PET images from PET/CT (PET CT ) and from PET/MR (PET MR ) were analysed for tracer-positive lesions. Regional tracer uptake in these foci was quantified using volumes of interest, and maximal and average standardized uptake values (SUV max and SUV avg , respectively) were calculated. Of the 46 patients, 43 were eligible for comparison and statistical analysis. All lesions except one identified by PET CT were identified by PET MR (99.2 %). In 38 patients (88.4 %), the same number of foci were identified by PET CT and by PET MR . In four patients, more lesions were identified by PET MR than by PET CT , in one patient PET CT revealed an additional focus compared to PET MR . The mean SUV max and SUV avg of all lesions determined by PET MR were by 21 % and 11 % lower, respectively, than the values determined by PET CT (p CT and PET MR were minor, but statistically significant. Nevertheless, a more detailed study of the quantitative accuracy of PET MR and the factors governing it is needed to ultimately assess its accuracy in measuring tissue tracer concentrations. (orig.)

Dynamic multidetector CT and non-contrast-enhanced MR for right adrenal vein imaging: comparison with catheter venography in adrenal venous sampling

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Ota, Hideki; Seiji, Kazumasa; Kawabata, Masahiro; Satani, Nozomi; Matsuura, Tomonori; Tominaga, Junya; Takase, Kei [Tohoku University Hospital, Department of Diagnostic Radiology, Sendai (Japan); Omata, Kei; Ono, Yoshikiyo; Iwakura, Yoshitsugu; Morimoto, Ryo; Kudo, Masataka; Satoh, Fumitoshi; Ito, Sadayoshi [Tohoku University Hospital, Division of Nephrology, Endocrinology and Vascular Medicine, Sendai (Japan)

2016-03-15

To evaluate visualization of the right adrenal vein (RAV) with multidetector CT and non-contrast-enhanced MR imaging in patients with primary aldosteronism. A total of 125 patients (67 men) scheduled for adrenal venous sampling (AVS) were included. Dynamic 64-detector-row CT and balanced steady-state free precession-based non-contrast-enhanced 3-T MR imaging were performed. RAV visualization based on a four-point score was documented. Both anatomical location and variation on cross-sectional imaging were evaluated, and the findings were compared with catheter venography as the gold standard. The RAV was visualized in 93.2 % by CT and 84.8 % by MR imaging (p = 0.02). Positive predictive values of RAV visualization were 100 % for CT and 95.2 % for MR imaging. Imaging score was significantly higher in CT than MR imaging (p < 0.01). The RAV formed a common trunk with an accessory hepatic vein in 16 % of patients. The RAV orifice level on cross-sectional imaging was concordant with catheter venography within the range of 1/3 vertebral height in >70 % of subjects. Success rate of AVS was 99.2 %. Dynamic CT is a reliable way to map the RAV prior to AVS. Non-contrast-enhanced MR imaging is an alternative when there is a risk of complication from contrast media or radiation exposure. (orig.)

Recurrent postoperative sciatica: Evaluation with MR imaging and enhanced CT

International Nuclear Information System (INIS)

Duoauferrier, R.; Frocrain, L.; Husson, J.L.

1987-01-01

The authors prospectively compared surface coil MR (SCMR) imaging and CT with iodinate contrast enhancement in 50 patients with recurrent postoperative sciatica. Of the 50 patients enrolled in the study, surgical treatment was elected in 27 patients after independent examination of SCMR imaging and enhanced CT. All predictions made with the 27 SCMR images were surgically confirmed. The surgical findings were 20 recurrent disk herniations, five recurrent disk herniations with scar tissue, one disk herniation above the level of diskectomy, and one disk herniation below the level of diskectomy. The surgical findings of the 12 patients who had scar tissue on CT were seven recurrent disk herniations, four recurrent disk herniations with scar tissue, and one disk herniation below the operated level. SCMR imaging was more sensitive and more specific than CT to differentiate scar tissue from recurrent disk herniation

Preoperative detection of hepatocellular carcinoma: comparison of combined constrast-enhanced MR imaging and combined CT during arterial portography and CT hepatic arteriography

International Nuclear Information System (INIS)

Kwak, H.S.; Kim, C.S.; Lee, J.M.; Seoul National University Medical Research Center

2004-01-01

The aim of this study was to compare Gd-DTPA-enhanced dynamic MR images, superparamagnetic iron oxide (SPIO)-enhanced MR images, combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images, vs combined CT arterial portography (CTAP) and CT hepatic arteriography (CTHA), in the detection of hepatocellular carcinoma (HCC) using receiver operating characteristic (ROC) analysis. Twenty-four patients with 38 nodular HCCs (5-60 mm, mean 23.0 mm) were retrospectively analyzed. Image reviews were conducted on a liver segment-by-segment basis. A total of 192 segments, including 36 segments with 38 HCC, were reviewed independently by three radiologists. Each radiologist read four sets of images (set 1, unenhanced and Gd-DTPA-enhanced dynamic MR images; set 2, unenhanced and SPIO-enhanced MR images; set 3, combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images; set 4, combined CTAP and CTHA). To minimize any possible learning bias, the reviewing order was randomized and the reviewing procedure was performed in four sessions at 2-week intervals. The diagnostic accuracy (Az values) for HCCs of combined CTAP and CTHA, combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images, Gd-DTPA-enhanced dynamic MR images, and SPIO-enhanced MR images for all observers were 0.934, 0.963, 0.878, and 0.869, respectively. The diagnostic accuracy of combined CTAP and CTHA and combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images was significantly higher than Gd-DTPA-enhanced dynamic MR images or SPIO-enhanced MR images (p<0.005). The mean specificity of combined CTAP and CTHA (93%) and combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images (95%) was significantly higher than Gd-DTPA-enhanced dynamic MR images (87%) or SPIO-enhanced MR images (88%; p<0.05). Combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images may obviate the need for more invasive combined CTAP and CTHA for the preoperative evaluation of patients with HCC

Bile Duct Hamartomas: US, CT and MR Findings in Eight Patients, Focusing on the US Findings

International Nuclear Information System (INIS)

Ahn, Jae Hong; Kim, Min Jeong; Kim, Pyo Nyun; Ha, Hyun Kwon; Lee, Moon Gyu; Han, Heon; Kim, Sam Soo; Jang, Kyung Mi

2005-01-01

To describe the US, CT and MR findings in eight patients with bile duct hamartomas. Bile duct hamartomas were diagnosed in eight patients (5 men and 3 women; age range, 41-69 years; mean age, 56 years) by liver biopsy. The US, CT and MR findings were retrospectively reviewed. Ultrasonographic ally, the bile duct hamartomas presented diffuse inhomogeneous and coarse echo texture with focal lesions, including bright spotty echoes or small hyperechoic nodules (n=7), hypoechoic nodules (n=7) and comet-tail echo (n=3) in seven patients. 16 of the 39 definable hypoechoic nodules that ranged in size from 5 mm to 16mm showed posterior enhancement. CT revealed innumerable hypodense nodules measuring 2-5 mm (n=3), 2-13 mm (n=1), 2-15 mm (n=2) and 2-18 mm (n=1) in seven patients. They were usually irregular in shape and showed no enhancement, but became more apparent after the administration of intravenous contrast medium. The innumerable hypodense nodules on enhanced CT scans were uniformly (n=5) or non uniformly (n=2) distributed throughout the liver. In four patients, MR images showed multiple small cyst-like lesions 2-13 mm in diameter. These small cyst like lesions were much more apparent on T2-weighted images or MR cholangiography. The diagnosis was made by either core-needle or wedge biopsy. In one patient, a small single lesion on the liver surface was not visible on the imaging studies. Pathologic examination revealed multiple bile duct hamartomas of varying size or microhamartomas. Although the bile duct hamartomas on CT and MR presented as numerous intrahepatic, small cyst-like lesions, they on US showed variable findings consisting of inhomogeneous and coarse echo texture with focal lesions, including bright spotty echoes or small hyperechoic nodules, hypoechoic nodules, and comet-tail echoes

CT and MR features of xanthogranulomatous cholecystitis: An analysis of consecutive 49 cases

International Nuclear Information System (INIS)

Zhao, Feng; Lu, Pu-Xuan; Yan, Sen-Xiang; Wang, Gao-Feng; Yuan, Jing; Zhang, Shi-Zheng; Wang, Yi-Xiang J.

2013-01-01

Objective: To study the CT and MR features of xanthogranulomatous cholecystitis (XGC). Materials and methods: 49 patients had pathologically confirmed XGC. All patients underwent contrast enhanced CT, and 10 patients had additional plain MRI. The CT and MRI results were retrospectively analyzed. Results: On CT, all patients had thickening of gallbladder wall, with 87.8% cases showed diffuse thickening. 85.7% cases had intramural hypo-attenuated nodules in the thickened wall. Continuous mucosal line and luminal surface enhancement were noted in 79.6% and 85.7% cases, respectively. Gallbladder stones were seen in 69.4% patients. The coexistence of the above 5 CT features was seen in 40% cases, and 80% cases had the coexistence of ≥4 features. Diffused gallbladder wall thickening in XGC is more likely to have disrupted mucosal line, and XGC with disrupted mucosal line is more likely to be associated with liver infiltration. In 60% patients the inflammatory process extended beyond gallbladder, with the interface between gallbladder and liver and/or the surrounding fat blurred. 40% cases had an early enhancement of liver parenchyma. Infiltration to other surrounding tissues included bowel (n = 3), stomach (n = 2), and abdominal wall (n = 1). On MR images, 7 of 9 intramural nodules in 7 subjects with T1-weighted dual echo MR images showed higher signal intensity on in-phase images than out-of-phase images. Conclusion: Coexisting of diffuse gallbladder wall thickening, hypo-attenuated intramural nodules, continuous mucosal line, luminal surface enhancement, and gallbladder stone highly suggest XGC. XGC frequently infiltrate liver and surrounding fat. Chemical-shift MRI helps classifying intramural nodules in the gallbladder wall

CT and MR features of xanthogranulomatous cholecystitis: An analysis of consecutive 49 cases

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Zhao, Feng [Department of Radiology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016 (China); Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong (China); Lu, Pu-Xuan [Department of Radiology, Shenzhen Third People' s Hospital, Guangdong Medical College, Shenzhen 518020 (China); Yan, Sen-Xiang [Department of Radiation Oncology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003 (China); Wang, Gao-Feng [Department of Radiology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016 (China); Yuan, Jing [Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong (China); Zhang, Shi-Zheng, E-mail: shizhengzhang@hotmail.com [Department of Radiology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016 (China); Wang, Yi-Xiang J., E-mail: yixiang_wang@cuhk.edu.hk [Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong (China); Department of Radiology, Shenzhen Third People' s Hospital, Guangdong Medical College, Shenzhen 518020 (China)

2013-09-15

Objective: To study the CT and MR features of xanthogranulomatous cholecystitis (XGC). Materials and methods: 49 patients had pathologically confirmed XGC. All patients underwent contrast enhanced CT, and 10 patients had additional plain MRI. The CT and MRI results were retrospectively analyzed. Results: On CT, all patients had thickening of gallbladder wall, with 87.8% cases showed diffuse thickening. 85.7% cases had intramural hypo-attenuated nodules in the thickened wall. Continuous mucosal line and luminal surface enhancement were noted in 79.6% and 85.7% cases, respectively. Gallbladder stones were seen in 69.4% patients. The coexistence of the above 5 CT features was seen in 40% cases, and 80% cases had the coexistence of ≥4 features. Diffused gallbladder wall thickening in XGC is more likely to have disrupted mucosal line, and XGC with disrupted mucosal line is more likely to be associated with liver infiltration. In 60% patients the inflammatory process extended beyond gallbladder, with the interface between gallbladder and liver and/or the surrounding fat blurred. 40% cases had an early enhancement of liver parenchyma. Infiltration to other surrounding tissues included bowel (n = 3), stomach (n = 2), and abdominal wall (n = 1). On MR images, 7 of 9 intramural nodules in 7 subjects with T1-weighted dual echo MR images showed higher signal intensity on in-phase images than out-of-phase images. Conclusion: Coexisting of diffuse gallbladder wall thickening, hypo-attenuated intramural nodules, continuous mucosal line, luminal surface enhancement, and gallbladder stone highly suggest XGC. XGC frequently infiltrate liver and surrounding fat. Chemical-shift MRI helps classifying intramural nodules in the gallbladder wall.

Comparison of manual and automatic MR-CT registration for radiotherapy of prostate cancer.

Science.gov (United States)

Korsager, Anne Sofie; Carl, Jesper; Riis Østergaard, Lasse

2016-05-08

In image-guided radiotherapy (IGRT) of prostate cancer, delineation of the clini-cal target volume (CTV) often relies on magnetic resonance (MR) because of its good soft-tissue visualization. Registration of MR and computed tomography (CT) is required in order to add this accurate delineation to the dose planning CT. An automatic approach for local MR-CT registration of the prostate has previously been developed using a voxel property-based registration as an alternative to a manual landmark-based registration. The aim of this study is to compare the two registration approaches and to investigate the clinical potential for replacing the manual registration with the automatic registration. Registrations and analysis were performed for 30 prostate cancer patients treated with IGRT using a Ni-Ti prostate stent as a fiducial marker. The comparison included computing translational and rotational differences between the approaches, visual inspection, and computing the overlap of the CTV. The computed mean translational difference was 1.65, 1.60, and 1.80mm and the computed mean rotational difference was 1.51°, 3.93°, and 2.09° in the superior/inferior, anterior/posterior, and medial/lateral direction, respectively. The sensitivity of overlap was 87%. The results demonstrate that the automatic registration approach performs registrations comparable to the manual registration.

Neoadjuvant chemotherapy in breast cancer: prediction of pathologic response with PET/CT and dynamic contrast-enhanced MR imaging--prospective assessment.

Science.gov (United States)

Tateishi, Ukihide; Miyake, Mototaka; Nagaoka, Tomoaki; Terauchi, Takashi; Kubota, Kazunori; Kinoshita, Takayuki; Daisaki, Hiromitsu; Macapinlac, Homer A

2012-04-01

To clarify whether fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging performed after two cycles of neoadjuvant chemotherapy (NAC) can be used to predict pathologic response in breast cancer. Institutional human research committee approval and written informed consent were obtained. Accuracy after two cycles of NAC for predicting pathologic complete response (pCR) was examined in 142 women (mean age, 57 years: range, 43-72 years) with histologically proved breast cancer between December 2005 and February 2009. Quantitative PET/CT and DCE MR imaging were performed at baseline and after two cycles of NAC. Parameters of PET/CT and of blood flow and microvascular permeability at DCE MR were compared with pathologic response. Patients were also evaluated after NAC by using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 based on DCE MR measurements and European Organization for Research and Treatment of Cancer (EORTC) criteria and PET Response Criteria in Solid Tumors (PERCIST) 1.0 based on PET/CT measurements. Multiple logistic regression analyses were performed to examine continuous variables at PET/CT and DCE MR to predict pCR, and diagnostic accuracies were compared with the McNemar test. Significant decrease from baseline of all parameters at PET/CT and DCE MR was observed after NAC. Therapeutic response was obtained in 24 patients (17%) with pCR and 118 (83%) without pCR. Sensitivity, specificity, and accuracy to predict pCR were 45.5%, 85.5%, and 82.4%, respectively, with RECIST and 70.4%, 95.7%, and 90.8%, respectively, with EORTC and PERCIST. Multiple logistic regression revealed three significant independent predictors of pCR: percentage maximum standardized uptake value (%SUV(max)) (odds ratio [OR], 1.22; 95% confidence interval [CI]: 1.11, 1.34; P PET/CT is superior to DCE MR for the prediction of pCR (%SUV(max) [90.1%] vs %κ

Characterization of liver lesions with mangafodipir trisodium-enhanced MR imaging: multicenter study comparing MR and dual-phase spiral CT

NARCIS (Netherlands)

M. Oudkerk (Matthijs); C.G. Torres; B. Song; M. Konig; J. Grimm; J. Fernandez-Cuadrado; B. op de Beeck; M. Marquardt; P. van Dijk (Pieter); J.C. de Groot (Jan Cees)

2002-01-01

textabstractPURPOSE: To evaluate whether mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) imaging surpasses dual-phase spiral computed tomography (CT) in differentiating focal liver lesions. MATERIALS AND METHODS: One hundred forty-five patients who had or were

Imaging techniques and investigation protocols in pediatric emergency imaging; Aufnahmetechnik und Untersuchungsprotokolle beim paediatrischen Notfall

Energy Technology Data Exchange (ETDEWEB)

Scharitzer, M.; Hoermann, M.; Puig, S.; Prokop, M. [Universitaetsklinik fuer Radiodiagnostik, Wien (Austria)

2002-03-01

Paediatric emergencies demand a quick and efficient radiological investigation with special attention to specific adjustments related to patient age and radiation protection. Imaging modalities are improving rapidly and enable to diagnose childhood diseases and injuries more quickly, accurately and safely. This article provides an overview of imaging techniques adjusted to the age of the child and an overview of imaging strategies of common paediatric emergencies. Optimising the imaging parameters (digital radiography, different screen-film systems, exposure specifications) allows for substantial reduction of radiation dose. Spiral- and multislice-CT reduce scan time and enable a considerable reduction of radiation exposure if scanning parameters (pitch setting, tube current) are properly adjusted. MRI is still mainly used for neurological or spinal emergencies despite the advent of fast imaging sequences. The radiologist's task is to select an appropriate imaging strategy according to expected differential diagnosis and to adjust the imaging techniques to the individual patient. (orig.) [German] Das akut erkrankte Kind erfordert eine rasche radiologische Abklaerung mit besonderer Beruecksichtung der geaenderten Untersuchungsparameter bei gleichzeitig hohem Anspruch an den Strahlenschutz. Hochaufloesende Schallkoepfe, Multislice-CT und schnelle MR-Sequenzen erlauben eine bessere Anpassung der Untersuchungsmethoden an die Beduerfnisse in der Kinderradiologie. Ziel dieses Artikels ist eine Uebersicht ueber die verschiedenen radiologischen Untersuchungstechniken sowie deren Anpassung an kindliche Anforderungen und die Angabe von Untersuchungsalgorithmen der haeufigsten paediatrischen Notfaelle. In der Projektionsradiographie erlaubt die Optimierung der Aufnahmetechnik (digitale Radiographie, unterschiedliche Klassen von Film-Folien-Systemen, Belichtungsparameter) eine deutliche Reduktion der Strahlendosis bei diagnostisch ausreichender Qualitaet. Spiral- oder

Evaluation of whole‐body MR to CT deformable image registration

Science.gov (United States)

Akbarzadeh, A.; Gutierrez, D.; Baskin, A.; Ay, M.R.; Ahmadian, A.; Alam, N. Riahi; Lövblad, KO

2013-01-01

Multimodality image registration plays a crucial role in various clinical and research applications. The aim of this study is to present an optimized MR to CT whole‐body deformable image registration algorithm and its validation using clinical studies. A 3D intermodality registration technique based on B‐spline transformation was performed using optimized parameters of the elastix package based on the Insight Toolkit (ITK) framework. Twenty‐eight (17 male and 11 female) clinical studies were used in this work. The registration was evaluated using anatomical landmarks and segmented organs. In addition to 16 anatomical landmarks, three key organs (brain, lungs, and kidneys) and the entire body volume were segmented for evaluation. Several parameters — such as the Euclidean distance between anatomical landmarks, target overlap, Dice and Jaccard coefficients, false positives and false negatives, volume similarity, distance error, and Hausdorff distance — were calculated to quantify the quality of the registration algorithm. Dice coefficients for the majority of patients (>75%) were in the 0.8–1 range for the whole body, brain, and lungs, which satisfies the criteria to achieve excellent alignment. On the other hand, for kidneys, Dice coefficients for volumes of 25% of the patients meet excellent volume agreement requirement, while the majority of patients satisfy good agreement criteria (>0.6). For all patients, the distance error was in 0–10 mm range for all segmented organs. In summary, we optimized and evaluated the accuracy of an MR to CT deformable registration algorithm. The registered images constitute a useful 3D whole‐body MR‐CT atlas suitable for the development and evaluation of novel MR‐guided attenuation correction procedures on hybrid PET‐MR systems. PACS number: 07.05.Pj PMID:23835382

CT synthesis in the head & neck region for PET/MR attenuation correction: an iterative multi-atlas approach

Energy Technology Data Exchange (ETDEWEB)

Burgos, Ninon [Translational Imaging Group, Centre for Medical Image Computing, University College London, London (United Kingdom); Cardoso, M Jorge; Modat, Marc [Translational Imaging Group, Centre for Medical Image Computing, University College London, London (United Kingdom); Dementia Research Centre, University College London, London (United Kingdom); Punwani, Shonit [Division of Imaging, University College London Hospitals, London (United Kingdom); Centre for Medical Imaging, University College London, London (United Kingdom); Atkinson, David [Centre for Medical Imaging, University College London, London (United Kingdom); Arridge, Simon R [Centre for Medical Image Computing, University College London, London (United Kingdom); Hutton, Brian F [Institute of Nuclear Medicine, University College London Hospitals, London (United Kingdom); Ourselin, Sébastien [Translational Imaging Group, Centre for Medical Image Computing, University College London, London (United Kingdom); Dementia Research Centre, University College London, London (United Kingdom)

2015-05-18

In this work, we propose to tackle the problem of attenuation correction in the head and neck by synthesising CT from MR images using an iterative multi-atlas approach. The proposed method relies on pre-acquired T2-weighted MRI and CT images of the neck. For each subject, the MRI is non-rigidly mapped to the CT. To synthesise a pseudo CT, all the MRIs in the database are first registered to the target MRI. This registration consists of a robust affine followed by a non-rigid registration. The pseudo CT is obtained by fusing the mapped atlases according to their morphological similarity to the target. In contrast to CTs, T2 images do not provide a good estimate of the bone location. Combining multiple modalities at both the registration and image similarity stages is expected to provide more realistic mappings and to reduce the bias. An initial pseudo CT (pCT) is combined with the target MRI to form a MRI-pCT pair. The MRI-pCT pair is registered to all the MRI-CT pairs from the database. An improved pseudo CT is obtained by fusing the mapped MRI-CT pairs according to their morphological similarity to the target MRI-pCT pair. Results showed that the proposed CT synthesis algorithm based on a multi-atlas information propagation scheme and iterative process is able to synthesise pseudo CT images in a region challenging for registration algorithms. The results also demonstrate that the robust affine decreases the absolute error compared to the classic approach and that the bone refinement process reduces the bias in the bone region. The proposed method could be used to correct for attenuation PET/MR data, but also for dosimetry calculations in the context of MR-based radiotherapy treatment planning.

Tomography methods for diagnostic examination of cerebrovascular disease: a comparative evaluation of SPECT, PET and MR/CT findings

International Nuclear Information System (INIS)

Reiche, W.; Kaiser, H.J.; Weiller, C.; Altehoefer, C.; Buell, U.; Isensee, C.

1991-01-01

Single Photon Emissions Computerized Tomography (SPECT), Positron Emissions Tomography (PET), Magnetic Resonance Tomography (MR), and Transmission Computerized Tomography (CT) complement each other and lead to a consideration of the cerebrovascular disease under patho-physiological aspects. Indications for the combined application of functionally oriented (SPECT/PET) and morphologically oriented (CT/MR) examination methods with cerebrovascular disease are presented. (orig./MG) [de

Design of a multimodal ({sup 1}H/{sup 23}Na MR/CT) anthropomorphic thorax phantom

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Neumann, Wiebke; Lietzmann, Florian; Schad, Lothar R.; Zoellner, Frank G. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine

2017-08-01

This work proposes a modular, anthropomorphic MR and CT thorax phantom that enables the comparison of experimental studies for quantitative evaluation of deformable, multimodal image registration algorithms and realistic multi-nuclear MR imaging techniques. A human thorax phantom was developed with insertable modules representing lung, liver, ribs and additional tracking spheres. The quality of human tissue mimicking characteristics was evaluated for {sup 1}H and {sup 23}Na MR as well as CT imaging. The position of landmarks in the lung lobes was tracked during CT image acquisition at several positions during breathing cycles. {sup 1}H MR measurements of the liver were repeated after seven months to determine long term stability. The modules possess HU, T{sub 1} and T{sub 2} values comparable to human tissues (lung module: -756 ± 148 HU, artificial ribs: 218 ± 56 HU (low CaCO{sub 3} concentration) and 339 ± 121 (high CaCO{sub 3} concentration), liver module: T{sub 1} = 790 ± 28 ms, T{sub 2} = 65 ± 1 ms). Motion analysis showed that the landmarks in the lung lobes follow a 3D trajectory similar to human breathing motion. The tracking spheres are well detectable in both CT and MRI. The parameters of the tracking spheres can be adjusted in the following ranges to result in a distinct signal: HU values from 150 to 900 HU, T{sub 1} relaxation time from 550 ms to 2000 ms, T{sub 2} relaxation time from 40 ms to 200 ms. The presented anthropomorphic multimodal thorax phantom fulfills the demands of a simple, inexpensive system with interchangeable components. In future, the modular design allows for complementing the present set up with additional modules focusing on specific research targets such as perfusion studies, {sup 23}Na MR quantification experiments and an increasing level of complexity for motion studies.

Sonography, CT and MR in soft part growths in the head and neck region

International Nuclear Information System (INIS)

Brinkmann, G.; Brix, F.; Beigel, A.

1990-01-01

14 patients with a space-occupying growth in the head and neck region were examined via sonography, CT and MR to explore and demonstrate by means of a prospective comparative study the possibilities offered by these three imaging methods. Stages are best diagnosed by means of sonography; the leading role of this method is undisputed. To clarify sonographically unclear findings and especially in pre-surgery planning, MR offers advantages over CT on account of the high soft-part contrast and multiplanar visualisation. However, it is impossible or very difficult to differentiate abscesses and lymphadenitides from malignant growths with these three methods solely on the basis of image-morphological criteria. (orig.) [de

Evaluation of the outcome of CT and MR imaging in pediatric patients with bilateral sensorineural hearing loss.

Science.gov (United States)

van Beeck Calkoen, E A; Merkus, P; Goverts, S T; van de Kamp, J M; Mulder, M F; Sanchez Aliaga, E; Hensen, E F

2018-05-01

To evaluate the clinically relevant abnormalities as visualized on CT and MR imaging in children with symmetric and asymmetric bilateral sensorineural hearing loss (SNHL), in relation to age and the severity of hearing loss. Retrospective cohort study. Tertiary referral otology and audiology center. From January 2006 until January 2016, a total of 207 children diagnosed with symmetric and asymmetric bilateral SNHL were included. They underwent CT and/or MR imaging for the evaluation of the etiology of their hearing loss. Radiologic abnormalities associated with SNHL. 302 scans were performed in 207 children (median age of 0.8 years old) with bilateral SNHL. The most frequently identified cause of bilateral SNHL was a malformation of the labyrinth. The combined diagnostic yield of CT and MR imaging was 32%. The diagnostic yield of MR (34%) was considerably higher than that of CT (20%). We found a higher rate of abnormalities in children with profound hearing loss (41%) compared to milder hearing loss (8-29%), and in asymmetric SNHL (52%) compared to symmetric SNHL (30%). Imaging is essential in the etiologic evaluation of children with bilateral SNHL. The highest diagnostic yield is found in children with bilateral asymmetric SNHL or profound SNHL. Based on our findings, MR is the primary imaging modality of choice in the etiological evaluation of children with bilateral SNHL because of its high diagnostic yield. Copyright © 2018. Published by Elsevier B.V.

MR spectroscopy in metabolic disorders of the brain; MR-Spektroskopie bei Stoffwechselerkrankungen des Gehirns

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, U. [Universitaetsklinikum des Saarlandes, Klinik fuer Diagnostische und Interventionelle Neuroradiologie, Homburg/Saar (Germany)

2017-06-15

Metabolic disorders of the brain often present a particular challenge for the neuroradiologist, since the disorders are rare, changes on conventional MR are often non-specific and there are numerous differential diagnoses for the white substance lesions. As a complementary method to conventional brain MRI, MR spectroscopy may help to reduce the scope of the differential diagnosis. Entities with specific MR spectroscopy patterns are Canavan disease, maple syrup urine disease, nonketotic hyperglycinemia and creatine deficiency. (orig.) [German] Die Diagnostik metabolischer Erkrankungen des Gehirns stellt eine besondere Herausforderung in der Neuroradiologie dar, da die Erkrankungen insgesamt selten, die bildmorphologischen Befunde haeufig unspezifisch sind und es eine Vielzahl von Differenzialdiagnosen fuer die Veraenderungen der weissen Substanz gibt. Als zusaetzliche Technik kann die MR-Spektroskopie bei Stoffwechselerkrankungen helfen, die Diagnose einzugrenzen. Krankheitsentitaeten, die spezifische Veraenderungen in der Spektroskopie aufweisen, sind der Morbus Canavan, die Ahornsirupkrankheit, die nichtketotische Hyperglyzinaemie und Kreatinmangelsyndrome. (orig.)

The EPTN consensus-based atlas for CT- and MR-based contouring in neuro-oncology.

Science.gov (United States)

Eekers, Daniëlle Bp; In 't Ven, Lieke; Roelofs, Erik; Postma, Alida; Alapetite, Claire; Burnet, Neil G; Calugaru, Valentin; Compter, Inge; Coremans, Ida E M; Høyer, Morton; Lambrecht, Maarten; Nyström, Petra Witt; Romero, Alejandra Méndez; Paulsen, Frank; Perpar, Ana; de Ruysscher, Dirk; Renard, Laurette; Timmermann, Beate; Vitek, Pavel; Weber, Damien C; van der Weide, Hiske L; Whitfield, Gillian A; Wiggenraad, Ruud; Troost, Esther G C

2018-03-13

To create a digital, online atlas for organs at risk (OAR) delineation in neuro-oncology based on high-quality computed tomography (CT) and magnetic resonance (MR) imaging. CT and 3 Tesla (3T) MR images (slice thickness 1 mm with intravenous contrast agent) were obtained from the same patient and subsequently fused. In addition, a 7T MR without intravenous contrast agent was obtained from a healthy volunteer. Based on discussion between experienced radiation oncologists, the clinically relevant organs at risk (OARs) to be included in the atlas for neuro-oncology were determined, excluding typical head and neck OARs previously published. The draft atlas was delineated by a senior radiation oncologist, 2 residents in radiation oncology, and a senior neuro-radiologist incorporating relevant available literature. The proposed atlas was then critically reviewed and discussed by European radiation oncologists until consensus was reached. The online atlas includes one CT-scan at two different window settings and one MR scan (3T) showing the OARs in axial, coronal and sagittal view. This manuscript presents the three-dimensional descriptions of the fifteen consensus OARs for neuro-oncology. Among these is a new OAR relevant for neuro-cognition, the posterior cerebellum (illustrated on 7T MR images). In order to decrease inter- and intra-observer variability in delineating OARs relevant for neuro-oncology and thus derive consistent dosimetric data, we propose this atlas to be used in photon and particle therapy. The atlas is available online at www.cancerdata.org and will be updated whenever required. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

CT and MRI in progressive multifocal leukoencephalopathy. CT und MRT der progressiven multifokalen Leukenzephalopathie (PML)

Energy Technology Data Exchange (ETDEWEB)

Lanfermann, H. (Inst. und Poliklinik fuer Radiologische Diagnostik, Koeln Univ. (Germany)); Heindel, W. (Inst. und Poliklinik fuer Radiologische Diagnostik, Koeln Univ. (Germany)); Schroeder, R. (Neuropathologie des Inst. fuer Pathologie, Koeln Univ. (Germany)); Lackner, K. (Inst. und Poliklinik fuer Radiologische Diagnostik, Koeln Univ. (Germany))

1994-07-01

Radiological findings and course of progressive multifocal leukoencephalopathy in 14 patients (1 woman, 13 men; 13 HIV seropositive, 1 chronic lymphatic leukaemia) were analysed retrospectively and correlated with clinical symptoms. A total of 21 CT and 16 MRI studies were evaluated. CT scans and MR images of 9 patients, which had been obtained in less than two weeks, could be compared to each other. MRI was superior to CT: 6 lesions with a diameter of 1 cm and below were not detected on CT scans, in 5 patients the extent of lesions was underestimated. Cortical involvement, mass effect or signs of atrophy were missing. Only 1 of 65 lesions showed a tiny enhancement after Gd injection. Due to the pattern and spread of lesions, which showed a close correlation to the neurologic symptoms, three different types of PML are suggested: 1. Initial precentral demyelinisation with contralateral hemiparesis (n=8); 2. lesions in temporo-occipital locations with visual disturbances (n=2); 3. predominantly bilateral lesions of cerebellar white matter with ataxia (n=4). (orig.)

Deep Learning MR Imaging-based Attenuation Correction for PET/MR Imaging.

Science.gov (United States)

Liu, Fang; Jang, Hyungseok; Kijowski, Richard; Bradshaw, Tyler; McMillan, Alan B

2018-02-01

Purpose To develop and evaluate the feasibility of deep learning approaches for magnetic resonance (MR) imaging-based attenuation correction (AC) (termed deep MRAC) in brain positron emission tomography (PET)/MR imaging. Materials and Methods A PET/MR imaging AC pipeline was built by using a deep learning approach to generate pseudo computed tomographic (CT) scans from MR images. A deep convolutional auto-encoder network was trained to identify air, bone, and soft tissue in volumetric head MR images coregistered to CT data for training. A set of 30 retrospective three-dimensional T1-weighted head images was used to train the model, which was then evaluated in 10 patients by comparing the generated pseudo CT scan to an acquired CT scan. A prospective study was carried out for utilizing simultaneous PET/MR imaging for five subjects by using the proposed approach. Analysis of covariance and paired-sample t tests were used for statistical analysis to compare PET reconstruction error with deep MRAC and two existing MR imaging-based AC approaches with CT-based AC. Results Deep MRAC provides an accurate pseudo CT scan with a mean Dice coefficient of 0.971 ± 0.005 for air, 0.936 ± 0.011 for soft tissue, and 0.803 ± 0.021 for bone. Furthermore, deep MRAC provides good PET results, with average errors of less than 1% in most brain regions. Significantly lower PET reconstruction errors were realized with deep MRAC (-0.7% ± 1.1) compared with Dixon-based soft-tissue and air segmentation (-5.8% ± 3.1) and anatomic CT-based template registration (-4.8% ± 2.2). Conclusion The authors developed an automated approach that allows generation of discrete-valued pseudo CT scans (soft tissue, bone, and air) from a single high-spatial-resolution diagnostic-quality three-dimensional MR image and evaluated it in brain PET/MR imaging. This deep learning approach for MR imaging-based AC provided reduced PET reconstruction error relative to a CT-based standard within the brain compared

Tumoral calcium pyrophosphate dihydrate deposition disease with bone destruction in the shoulder. CT an MR findings in two cases

International Nuclear Information System (INIS)

Mizutani, H.; Ohba, S.; Sasaki, S.; Ando, K.; Mizutani, M.; Matsushita, Y.; Ohtsuka, T.; Terazawa, T.; Ijima, S.

1998-01-01

We report on specific CT and MR features in two cases of tumoral calcium pyrophosphate dihydrate deposition disease in the shoulder with unusually large tumors. CT revealed features that were specific to the disease. MR was useful for detecting the extent of the mass and for obtaining information on adjacent soft-tissue and bone-marrow changes. (orig.)

Correlation of CT and MR findings with clinical outcome

International Nuclear Information System (INIS)

Kim, Hak Soo; Kim, In One; Choi, Du Hwan; Yeon, Kyung Mo; Hwang, Yong Seung

1991-01-01

A retrospective analysis of the CT and MR findings of 14 pediatric patients with brain stem tumors was performed to evaluate whether the clinical outcome could be predicted from a radiographic pattern of the tumors. CT was performed in 11 patients and MR was performed in 14 patients. Ten patients were treated with radiation therapy (RT) alone, 2 patients with RT and chemotherapy, and 2 patients underwent subtotal resection. After treatment, 9 patients died within 10 months, and 5 patients were alive for 9 months to 51 months. There was no statistically significant correlation between survival and tumor location or size, but in 2 cases of exophytic growing tumor, a subtotal resection of the tumor was possible and the patients were alive for 9 months and 24 months, respectively. The tumors with a cystic portion and definite rim enhancement revealed a poor response to conventional RT, and all 6 patients died within 10 months. In conclusion, a better prognosis is predicted in the case of an exophytic growing tumor after surgical resection, but the definite ring-enhancing tumor showed a poor response on conventional RT. Also, we should consider a more active therapeutic approach such as hyperfractionated RT or combinations of chemotherapy to improve the prognosis

MR and CT imaging of pulmonary valved conduits in children and adolescents: normal appearance and complications

Energy Technology Data Exchange (ETDEWEB)

Tenisch, Estelle V.; Alamo, Leonor T.; Gudinchet, Francois [Lausanne University Hospital, Department of Medical Imaging, Lausanne (Switzerland); Sekarski, Nicole [Lausanne University Hospital, Department of Pediatrics, Lausanne (Switzerland); Hurni, Michel [Lausanne University Hospital, Department of Cardiovascular Surgery, Lausanne (Switzerland)

2014-12-15

The Contegra registered is a conduit made from the bovine jugular vein and then interposed between the right ventricle and the pulmonary artery. It is used for cardiac malformations in the reconstruction of right ventricular outflow tract. To describe both normal and pathological appearances of the Contegra registered in radiological imaging, to describe imaging of complications and to define the role of CT and MRI in postoperative follow-up. Forty-three examinations of 24 patients (17 boys and 7 girls; mean age: 10.8 years old) with Contegra registered conduits were reviewed. Anatomical description and measurements of the conduits were performed. Pathological items examined included stenosis, dilatation, plicature or twist, thrombus or vegetations, calcifications and valvular regurgitation. Findings were correlated to the echographic gradient through the conduit when available. CT and MR work-up showed Contegra registered stenosis (n = 12), dilatation (n = 9) and plicature or twist (n = 7). CT displayed thrombus or vegetations in the Contegra registered in three clinically infected patients. Calcifications of the conduit were present at CT in 12 patients and valvular regurgitation in three patients. The comparison between CT and/or MR results showed a good correlation between the echographic gradient and the presence of stenosis in the Contegra registered. CT and MR bring additional information about permeability and postoperative anatomy especially when echocardiography is inconclusive. Both techniques depict the normal appearance of the conduit, and allow comparison and precise evaluation of changes in the postoperative follow-up. (orig.)

Abstracts of the Charite-symposium 'CT and MR in medicine'

International Nuclear Information System (INIS)

1988-01-01

127 abstracts of papers read at the Charite-symposium are presented. They chiefly deal with the diagnostic application of computerized tomograhpy and NMR imaging in clinical and surgical medicine comprising the use of contrast media. CT and MR in relation to irradiation planning and possibilities in image processing such as the new picture archiving and communication system (PACS) are included as well

Current status of MR colonography.

LENUS (Irish Health Repository)

Thornton, Eavan

2010-01-01

The search for an acceptable colorectal cancer screening examination has led to the development of virtual colonoscopy, which includes both computed tomographic (CT) colonography and magnetic resonance (MR) colonography. As indicated by the much larger number of published studies on CT colonography than on MR colonography, multidetector CT appears to be more suitable for colorectal screening than does MR colonography, in part reflecting the ease and speed of performing CT, as well as the increased spatial resolution, decreased cost, and wider availability of CT colonography. The main advantage of MR colonography over CT colonography is that it does not use ionizing radiation, which has important implications for colorectal cancer screening. The use of dark-lumen MR colonography to screen patients for colorectal cancer as well as other abdominopelvic disease could make it more attractive than CT. With the integration of 3.0-T MR colonography, fecal tagging, and parallel imaging into research and clinical settings, new MR colonography protocols must be optimized. Future MR colonography research should address issues such as image characteristics, presence of artifacts, management of specific absorption rate, and hardware-related modifications.

CT and MR imaging of high cervical intradural lipomas

Energy Technology Data Exchange (ETDEWEB)

Oh, Joo Hyeong; Choi, Woo Suk; Lee, Sun Wha; Lim, Jae Hoon; Leem, Woon; Kim, Gook Ki; Rhee, Bong Arm [Kyung Hee University Hospital, Seoul (Korea, Republic of)

1988-04-15

Intradural spinal lipoma occurs in less than 1% of all spinal cord tumors. It has been described at every level of the spinal canal, although its most common location is the cervicothoracic and thoracic region. However, lipoma located in the high cervical region is very unusual. We described two cases, a teenager and an adult, with progressive neurologic deficit from such a lipomatous tumor, which were evaluated by CT scanning and MR imaging.

Atlas and toolbook of MR mammography; Lehratlas der MR-Mammographie

Energy Technology Data Exchange (ETDEWEB)

Fischer, U. [Universitaetsklinikum Goettingen (Germany). Abt. Roentgendiagnostik I; Brinck, U. [Universitaetsklinikum Goettingen (Germany). Abt. Pathologie und Pathologische Anatomie

2000-07-01

This richly illustrated toolbook and atlas contains information on all aspects of nmr diagnostic imaging of benign or malignant neoplasms of female and male mammary glands. It offers pinpointed guidance and insight for vocational training and continuing training of radiology assistants, students and medical radiologists. (orig./AJ) [German] Die MRT als hochaufloesendes und schaedigungsfreies Diagnostikum gewinnt gerade in der emotional stark besetzten Mammadiagnostik zunehmend an Bedeutung. Dennoch beherrschen nur wenige Zentren im deutschsprachigen Raum diese Technik, die - eine hohe Reproduzierbarkeit bei fehlender Belastung fuer die Patientin bietet, - invasive Karzinome bereits ab einer Groesse von 5 mm mit hoher Zuverlaessigkeit ausschliessen kann und - gerade bei widerspruechlichen Befunden zwischen klinischer Untersuchung, Roentgenmammographie und perkutaner Biopsie eine wesentliche Entscheidungshilfe bieten kann. Aus einem der fuehrenden Zentren in der MR-Mammographie wurde daher dieser praxisnahe, opulent ausgestattete und weit ueber die reine Bildinformation hinausgehende 'Einstiegs- und Lehratlas' entwickelt. Er bietet Radiologen in Fort- und Weiterbildung, aber auch Gynaekologen mit ueber 400 Abbildungen klare Antworten auf die Fragen. (orig./AJ)

Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

International Nuclear Information System (INIS)

Viswanathan, Akila N.; Erickson, Beth; Gaffney, David K.; Beriwal, Sushil; Bhatia, Sudershan K.; Lee Burnett, Omer; D'Souza, David P.; Patil, Nikhilesh; Haddock, Michael G.; Jhingran, Anuja; Jones, Ellen L.; Kunos, Charles A.; Lee, Larissa J.; Lin, Lilie L.; Mayr, Nina A.; Petersen, Ivy; Petric, Primoz; Portelance, Lorraine; Small, William; Strauss, Jonathan B.

2014-01-01

Objective: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy. Methods and Materials: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case. Results: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR. Conclusion: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at (http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx)

Comparison and Consensus Guidelines for Delineation of Clinical Target Volume for CT- and MR-Based Brachytherapy in Locally Advanced Cervical Cancer

Energy Technology Data Exchange (ETDEWEB)

Viswanathan, Akila N., E-mail: aviswanathan@lroc.harvard.edu [Brigham and Women' s Hospital/Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Erickson, Beth [Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Gaffney, David K. [University of Utah Huntsman Cancer Hospital, Salt Lake City, Utah (United States); Beriwal, Sushil [University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Bhatia, Sudershan K. [University of Iowa, Iowa City, Iowa (United States); Lee Burnett, Omer [University of Alabama, Birmingham, Alabama (United States); D' Souza, David P.; Patil, Nikhilesh [London Health Sciences Centre and Western University, London, Ontario (Canada); Haddock, Michael G. [Mayo Medical Center, Rochester, Minnesota (United States); Jhingran, Anuja [University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Jones, Ellen L. [University of North Carolina, Chapel Hill, North Carolina (United States); Kunos, Charles A. [Case Western Reserve University, Cleveland, Ohio (United States); Lee, Larissa J. [Brigham and Women' s Hospital/Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Lin, Lilie L. [University of Pennsylvania, Philadelphia, Pennsylvania (United States); Mayr, Nina A. [University of Washington, Seattle, Washington (United States); Petersen, Ivy [Mayo Medical Center, Rochester, Minnesota (United States); Petric, Primoz [Division of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana (Slovenia); Department of Radiation Oncology, National Center for Cancer Care and Research, Doha (Qatar); Portelance, Lorraine [University of Miami Miller School of Medicine, Miami, Florida (United States); Small, William [Loyola University Strich School of Medicine, Chicago, Illinois (United States); Strauss, Jonathan B. [The Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, Illinois (United States); and others

2014-10-01

Objective: To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3-Tesla (3-T) magnetic resonance (MR) image-based cervical-cancer brachytherapy. Methods and Materials: Twenty-three experts in gynecologic radiation oncology contoured the same 3 cervical cancer brachytherapy cases: 1 stage IIB near-complete response (CR) case with a tandem and ovoid, 1 stage IIB partial response (PR) case with tandem and ovoid with needles, and 1 stage IB2 CR case with a tandem and ring applicator. The CT contours were completed before the MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with κ statistics as a measure of agreement between participants. The conformity index was calculated for each of the 6 data sets. Dice coefficients were generated to compare the CT and MR contours of the same case. Results: For all 3 cases, the mean tumor volume was smaller on MR than on CT (P<.001). The κ and conformity index estimates were slightly higher for CT, indicating a higher level of agreement on CT. The Dice coefficients were 89% for the stage IB2 case with a CR, 74% for the stage IIB case with a PR, and 57% for the stage IIB case with a CR. Conclusion: In a comparison of MR-contoured with CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast medium visible on the images at the time of brachytherapy. MR at the time of brachytherapy may be of greatest benefit in patients with large tumors with parametrial extension that have a partial or complete response to external beam. On the basis of these results, a 95% consensus volume was generated for CT and for MR. Online contouring atlases are available for instruction at (http://www.nrgoncology.org/Resources/ContouringAtlases/GYNCervicalBrachytherapy.aspx)

Feasibility of MR-only proton dose calculations for prostate cancer radiotherapy using a commercial pseudo-CT generation method

Science.gov (United States)

Maspero, Matteo; van den Berg, Cornelis A. T.; Landry, Guillaume; Belka, Claus; Parodi, Katia; Seevinck, Peter R.; Raaymakers, Bas W.; Kurz, Christopher

2017-12-01

A magnetic resonance (MR)-only radiotherapy workflow can reduce cost, radiation exposure and uncertainties introduced by CT-MRI registration. A crucial prerequisite is generating the so called pseudo-CT (pCT) images for accurate dose calculation and planning. Many pCT generation methods have been proposed in the scope of photon radiotherapy. This work aims at verifying for the first time whether a commercially available photon-oriented pCT generation method can be employed for accurate intensity-modulated proton therapy (IMPT) dose calculation. A retrospective study was conducted on ten prostate cancer patients. For pCT generation from MR images, a commercial solution for creating bulk-assigned pCTs, called MR for Attenuation Correction (MRCAT), was employed. The assigned pseudo-Hounsfield Unit (HU) values were adapted to yield an increased agreement to the reference CT in terms of proton range. Internal air cavities were copied from the CT to minimise inter-scan differences. CT- and MRCAT-based dose calculations for opposing beam IMPT plans were compared by gamma analysis and evaluation of clinically relevant target and organ at risk dose volume histogram (DVH) parameters. The proton range in beam’s eye view (BEV) was compared using single field uniform dose (SFUD) plans. On average, a (2%, 2 mm) gamma pass rate of 98.4% was obtained using a 10% dose threshold after adaptation of the pseudo-HU values. Mean differences between CT- and MRCAT-based dose in the DVH parameters were below 1 Gy (radiotherapy, is feasible following adaptation of the assigned pseudo-HU values.

Formation of multifunctional Fe3O4/Au composite nanoparticles for dual-mode MR/CT imaging applications

International Nuclear Information System (INIS)

Hu Yong; Li Jing-Chao; Shen Ming-Wu; Shi Xiang-Yang

2014-01-01

Recent advances with iron oxide/gold (Fe 3 O 4 /Au) composite nanoparticles (CNPs) in dual-modality magnetic resonance (MR) and computed tomography (CT) imaging applications are reviewed. The synthesis and assembly of “dumbbelllike” and “core/shell” Fe 3 O 4 /Au CNPs is introduced. Potential applications of some developed Fe 3 O 4 /Au CNPs as contrast agents for dual-mode MR/CT imaging applications are described in detail. (topical review - magnetism, magnetic materials, and interdisciplinary research)

CT-guided percutaneous neurolysis methods. State of the art and first results; CT-gesteuerte Neurolysen. Stand der Technik und aktuelle Ergebnisse

Energy Technology Data Exchange (ETDEWEB)

Schneider, B. [Abt. Radiodiagnostik, Radiologische Universitaetsklinik Heidelberg (Germany); Richter, G.M. [Abt. Radiodiagnostik, Radiologische Universitaetsklinik Heidelberg (Germany); Roeren, T. [Abt. Radiodiagnostik, Radiologische Universitaetsklinik Heidelberg (Germany); Kauffmann, G.W. [Abt. Radiodiagnostik, Radiologische Universitaetsklinik Heidelberg (Germany)

1996-09-01

We used 21G or 22G fine needles. All CT-guided percutaneous neurolysis methods require a proper blood coagulation. Most common CT scanners are suitable for neurolysis if there is enough room for maintaining sterile conditions. All neurolysis methods involve sterile puncture of the ganglia under local anesthesia, a test block with anesthetic and contrast agent to assess the clinical effect and the definitive block with a mixture of 96% ethanol and local anesthetic. This allows us to correct the position of the needle if we see improper distribution of the test block or unwanted side effects. Though inflammatory complications of the peritoneum due to puncture are rarely seen, we prefer the dorsal approach whenever possible. Results: Seven of 20 legs showed at least transient clinical improvement after CT-guided lumbar sympathectomies; 13 legs had to be amputated. Results of the methods in the literature differ. For lumbar sympathectomy, improved perfusion is reported in 39-89%, depending on the pre-selection of the patient group. Discussion: It was recently proved that sympathectomy not only improves perfusion of the skin but also of the muscle. The hypothesis of a steal effect after sympathectomy towards skin perfusion was disproved. Modern aggressive surgical and interventional treatment often leaves patients to sympathectomy whose reservers of collateralization are nearly exhausted. We presume this is the reason for the different results we found in our patient group. For thoracic sympathectomy the clinical treatment depends very much on the indications. Whereas palmar hyperhidrosis offers nearly 100% success, only 60-70% of patients with disturbance of perfusion have benefited. Results in celiac ganglia block also differ. Patients with carcinoma of the pancreas and other organs of the upper abdomen benefit in 80-100% of all cases, patients with chronic pancreatitis in 60-80%. (orig./VHE) [Deutsch] Thorakale und lumbale Sympathikolyse sowie die Zoeliakusblockade

CT and MR imaging of congenital abnormalities of the inner ear and internal auditory canal

International Nuclear Information System (INIS)

Casselman, Jan W.; Offeciers, Erwin F.; Foer, Bert de; Govaerts, Paul; Kuhweide, Rudy; Somers, Thomas

2001-01-01

The embryology of the inner ear must be known as many of the inner ear malformations present as a result of the arrest during the various stages of embryology. These malformations are described in this 'embryologic' perspective and specific names for certain malformations are no longer used. Both CT and MR can be used to look at inner ear malformations but often both techniques are complementary. However, CT is preferred when associated middle- or external ear malformations must be excluded. Magnetic resonance is preferred when subtle changes in the membranous labyrinth or abnormalities of the nerves in the internal auditory canal must be visualised. The CT and MR technique must however be adapted as more and more subtle congenital malformations can only be seen when the right technique is used. The heavily T2-weighted gradient-echo or fast spin-echo MR techniques are mandatory if malformations of the inner ear must be excluded. The purpose of this paper is to describe the techniques used to study these patients and to give an overview of the most frequent and important congenital malformations which can be found in the inner ear and internal auditory canal/cerebellopontine angle

Subject-specific bone attenuation correction for brain PET/MR: can ZTE-MRI substitute CT scan accurately?

Science.gov (United States)

Khalifé, Maya; Fernandez, Brice; Jaubert, Olivier; Soussan, Michael; Brulon, Vincent; Buvat, Irène; Comtat, Claude

2017-10-01

In brain PET/MR applications, accurate attenuation maps are required for accurate PET image quantification. An implemented attenuation correction (AC) method for brain imaging is the single-atlas approach that estimates an AC map from an averaged CT template. As an alternative, we propose to use a zero echo time (ZTE) pulse sequence to segment bone, air and soft tissue. A linear relationship between histogram normalized ZTE intensity and measured CT density in Hounsfield units (HU ) in bone has been established thanks to a CT-MR database of 16 patients. Continuous AC maps were computed based on the segmented ZTE by setting a fixed linear attenuation coefficient (LAC) to air and soft tissue and by using the linear relationship to generate continuous μ values for the bone. Additionally, for the purpose of comparison, four other AC maps were generated: a ZTE derived AC map with a fixed LAC for the bone, an AC map based on the single-atlas approach as provided by the PET/MR manufacturer, a soft-tissue only AC map and, finally, the CT derived attenuation map used as the gold standard (CTAC). All these AC maps were used with different levels of smoothing for PET image reconstruction with and without time-of-flight (TOF). The subject-specific AC map generated by combining ZTE-based segmentation and linear scaling of the normalized ZTE signal into HU was found to be a good substitute for the measured CTAC map in brain PET/MR when used with a Gaussian smoothing kernel of 4~mm corresponding to the PET scanner intrinsic resolution. As expected TOF reduces AC error regardless of the AC method. The continuous ZTE-AC performed better than the other alternative MR derived AC methods, reducing the quantification error between the MRAC corrected PET image and the reference CTAC corrected PET image.

Sectional depiction of the pelvic floor by CT, MR imaging and sheet plastination: computer-aided correlation and 3D model

Energy Technology Data Exchange (ETDEWEB)

Beyersdorff, D.; Taupitz, M.; Hamm, B. [Dept. of Radiology, Humboldt Univ., Berlin (Germany); Schiemann, T. [Inst. for Mathematics and Computer Science in Medicine, University of Hamburg (Germany); Kooijman, H. [Philips Medical Systems, Hamburg (Germany); Nicolas, V. [Dept. of Radiology and Nuclear Medicine, BG Kliniken Bergmannsheil, Bochum (Germany)

2001-04-01

The structures of the pelvic floor are clinically important but difficult to assess. To facilitate the understanding of the complicated pelvic floor anatomy on sectional images obtained by CT and MR imaging, and to make the representation more vivid, a computer-aided 3D model was created from a male and a female torso to develop a teaching tool. A male and a female cadaver torso were investigated by means of CT, MR imaging, and serial-section sheet plastination. A 3D reconstruction of the pelvic floor and adjacent structures was performed by fusion of CT and MR imaging data sets with sheet plastination sections. Corresponding sections from all three methods could be compared and visualized in their 3D context. Sheet plastination allows distinction of connective tissue, muscles, and pelvic organs down to a microscopic level. In combination with CT, MR imaging, and sheet plastination a 3D model of the pelvic floor offers a better understanding of the complex pelvic anatomy. This knowledge may be applied in the diagnostic imaging of urinary incontinence or prolapse and prior to prostate surgery. (orig.)

CT-diskography, diskomanometry and MR imaging as predictors of the outcome of lumbar percutaneous automated nucleotomy

Energy Technology Data Exchange (ETDEWEB)

Dullerud, R. [Ullevaal Univ. Hospital, Oslo (Norway). Dept. of Radiology; Amundsen, T. [Ullevaal Univ. Hospital, Oslo (Norway). Dept. Neurology; Lie, H. [Chrismed, Oslo (Norway); Juel, N.G. [Ullevaal Univ. Hospital, Oslo (Norway). Dept. of Physical Medicine; Magnaes, B. [Ullevaal Univ. Hospital, Oslo (Norway). Dept. of Neurosurgery

1995-11-01

This prospective study was performed to assess whether CT-diskography (CT-D), diskomanometry (DMM) including recording of the pain response, or the MR signal intensity of the disks are reliable predictors of the outcome of nucleotomy. Ninety-one patients, 44 females and 47 males aged 18-68 years (mean 37.4) treated at 99 disk levels were included. All had plain CT, MR imaging, CT-D and DMM performed prior to automated percutaneous nucleotomy with the Nucleotome R system. Sixity-nine (76%) of the patients responded well to treatment within 3 months. Due to recurrences, the success rate at 1 year was reduced to 65%. Except for better results following nucleotomy in patients with similar and identical pain as the presenting complaint provoked at diskography, no association was demonstrated between diskographic parameters, or loss of signal on MR, and the outcome. Better results were also seen in patients with a short history of disk disease, but not in patients with predominantly sciatica and focal hernias compared to those with predominantly low-back pain and diffuse posterior buldges. The results do not justify routine use of diskography prior to nucleotomy in patients with pathologic disks demonstrated by noninvasive methods and localizing sciatic pain. (orig./UG).

CT-diskography, diskomanometry and MR imaging as predictors of the outcome of lumbar percutaneous automated nucleotomy

International Nuclear Information System (INIS)

Dullerud, R.; Juel, N.G.; Magnaes, B.

1995-01-01

This prospective study was performed to assess whether CT-diskography (CT-D), diskomanometry (DMM) including recording of the pain response, or the MR signal intensity of the disks are reliable predictors of the outcome of nucleotomy. Ninety-one patients, 44 females and 47 males aged 18-68 years (mean 37.4) treated at 99 disk levels were included. All had plain CT, MR imaging, CT-D and DMM performed prior to automated percutaneous nucleotomy with the Nucleotome R system. Sixity-nine (76%) of the patients responded well to treatment within 3 months. Due to recurrences, the success rate at 1 year was reduced to 65%. Except for better results following nucleotomy in patients with similar and identical pain as the presenting complaint provoked at diskography, no association was demonstrated between diskographic parameters, or loss of signal on MR, and the outcome. Better results were also seen in patients with a short history of disk disease, but not in patients with predominantly sciatica and focal hernias compared to those with predominantly low-back pain and diffuse posterior buldges. The results do not justify routine use of diskography prior to nucleotomy in patients with pathologic disks demonstrated by noninvasive methods and localizing sciatic pain. (orig./UG)

Ductal adenocarcinoma and unusual differential diagnosis; Duktales Adenokarzinom und ungewoehnliche Differenzialdiagnosen

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Haage, P.; Schwartz, C.A.; Scharwaechter, C. [Universitaet Witten/Herdecke, Zentrum fuer Radiologie HELIOS Universitaetsklinikum Wuppertal, Wuppertal (Germany)

2016-04-15

Ductal pancreatic adenocarcinoma is by far the most common solid tumor of the pancreas. It has a very poor prognosis, especially in the more advanced stages which are no longer locally confined. Due to mostly unspecific symptoms, imaging is key in the diagnostic process. Because of the widespread use of imaging techniques, incidental findings are to a greater extent discovered in the pancreas, which subsequently entail further work-up. Ductal pancreatic adenocarcinoma can be mimicked by a large number of different lesions, such as anatomical variants, peripancreatic structures and tumors, rarer primary solid pancreatic tumors, cystic tumors, metastases or different variants of pancreatitis. Additionally, a number of precursor lesions can be differentiated. The correct classification is thus important as an early diagnosis of ductal pancreatic adenocarcinoma is relevant for the prognosis and because the possibly avoidable treatment is very invasive. All major imaging techniques are principally suitable for pancreatic imaging. In addition to sonography of the abdomen, usually the baseline diagnostic tool, computed tomography (CT) with its superior spatial resolution, magnetic resonance imaging (MRI) with its good soft tissue differentiation capabilities, possibly in combination with MR cholangiopancreatography (MRCP), endosonography with its extraordinary spatial resolution, conceivably with additional endoscopic retrograde CP or the option of direct biopsy and finally positron emission tomography CT (PET-CT) as a molecular imaging tool are all particularly useful modalities. The various techniques all have its advantages and disadvantages; depending on the individual situation they may need to be combined. (orig.) [German] Das duktale Adenokarzinom ist der weitaus haeufigste solide Tumor des Pankreas. Die Prognose ist sehr schlecht, insbesondere bei fortgeschrittenen, nicht mehr lokal begrenzten Tumoren. Bei meist unspezifischen geringen Beschwerden kommt der

Multiparametric and molecular imaging of breast tumors with MRI and PET/MRI; Multiparametrische und molekulare Bildgebung von Brusttumoren mit MRT und PET-MRT

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Pinker, K. [Medizinische Universitaet Wien, Universitaetsklinik fuer Radiologie und Nuklearmedizin, Division fuer Molekulare und Gender Bildgebung, Wien (Austria); Memorial Sloan-Kettering Cancer Center, Department of Radiology, Molecular Imaging and Therapy Service, New York (United States); State University of Florida, Department of Scientific Computing in Medicine, Florida (United States); Marino, M.A. [Medizinische Universitaet Wien, Universitaetsklinik fuer Radiologie und Nuklearmedizin, Division fuer Molekulare und Gender Bildgebung, Wien (Austria); Policlinico Universitario G. Martino, University of Messina, Department of Biomedical Sciences and Morphologic and Functional Imaging, Messina (Italy); Meyer-Baese, A. [State University of Florida, Department of Scientific Computing in Medicine, Florida (United States); Helbich, T.H. [Medizinische Universitaet Wien, Universitaetsklinik fuer Radiologie und Nuklearmedizin, Division fuer Molekulare und Gender Bildgebung, Wien (Austria)

2016-07-15

Magnetic resonance imaging (MRI) of the breast is an indispensable tool in breast imaging for many indications. Several functional parameters with MRI and positron emission tomography (PET) have been assessed for imaging of breast tumors and their combined application is defined as multiparametric imaging. Available data suggest that multiparametric imaging using different functional MRI and PET parameters can provide detailed information about the hallmarks of cancer and may provide additional specificity. Multiparametric and molecular imaging of the breast comprises established MRI parameters, such as dynamic contrast-enhanced MRI, diffusion-weighted imaging (DWI), MR proton spectroscopy ({sup 1}H-MRSI) as well as combinations of radiological and MRI techniques (e.g. PET/CT and PET/MRI) using radiotracers, such as fluorodeoxyglucose (FDG). Multiparametric and molecular imaging of the breast can be performed at different field-strengths (range 1.5-7 T). Emerging parameters comprise novel promising techniques, such as sodium imaging ({sup 23}Na MRI), phosphorus spectroscopy ({sup 31}P-MRSI), chemical exchange saturation transfer (CEST) imaging, blood oxygen level-dependent (BOLD) and hyperpolarized MRI as well as various specific radiotracers. Multiparametric and molecular imaging has multiple applications in breast imaging. Multiparametric and molecular imaging of the breast is an evolving field that will enable improved detection, characterization, staging and monitoring for personalized medicine in breast cancer. (orig.) [German] Die Magnetresonanztomographie (MRT) der Brust ist ein etabliertes nichtinvasives bildgebendes Verfahren mit vielfaeltigen Indikationen. In den letzten Jahren wurden zahlreiche funktionelle MRT- und Positronenemissionstomographie(PET)-Parameter in der Brustbildgebung evaluiert, und ihre kombinierte Anwendung ist als multiparametrische Bildgebung definiert. Bisherige Daten legen nahe, dass die multiparametrische Bildgebung mit MRT und PET

Correction of distortion of MR pictures for MR-guided robotic sterotactic procedures

International Nuclear Information System (INIS)

Jonckheere, E.A.; Kwoh, Y.S.

1988-01-01

Ever since magnetic resonance (MR) invaded the medical imaging field, it has played an increasingly important role and is even currently being considered for stereotactic guidance of probes in the brain. While MR pictures indeed convey more clinical information than CT, the geometry of MR pictures is, unfortunately, not as accurate as the geometry of CT pictures. In other words, if a square grid phantom is scanned, then the CT picture will show a square grid, while the MR picture will rather reveal a distorted grid. This distortion is primarily due to small variations in the static magnetic field. This small distortion does not impede radiological diagnosis; however, it is a source of concern if one contemplates utilizing the MR pictures for accurate stereotactic positioning of a probe at a very precise point in the brain. Another area of application where the distortion of the MR picture should be compensated for is the superposition of CT and MR pictures so that both informations could be used for diagnosis or stereotactic purposes. This paper essentially addresses the nonlinear distortion of MR pictures and how it could be compensated for through software manipulation of the MR picture

MR-based attenuation correction for cardiac FDG PET on a hybrid PET/MRI scanner: comparison with standard CT attenuation correction

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Vontobel, Jan; Liga, Riccardo; Possner, Mathias; Clerc, Olivier F.; Mikulicic, Fran; Veit-Haibach, Patrick; Voert, Edwin E.G.W. ter; Fuchs, Tobias A.; Stehli, Julia; Pazhenkottil, Aju P.; Benz, Dominik C.; Graeni, Christoph; Gaemperli, Oliver; Herzog, Bernhard; Buechel, Ronny R.; Kaufmann, Philipp A. [University Hospital Zurich, Department of Nuclear Medicine, Zurich (Switzerland)

2015-09-15

The aim of this study was to evaluate the feasibility of attenuation correction (AC) for cardiac {sup 18}F-labelled fluorodeoxyglucose (FDG) positron emission tomography (PET) using MR-based attenuation maps. We included 23 patients with no known cardiac history undergoing whole-body FDG PET/CT imaging for oncological indications on a PET/CT scanner using time-of-flight (TOF) and subsequent whole-body PET/MR imaging on an investigational hybrid PET/MRI scanner. Data sets from PET/MRI (with and without TOF) were reconstructed using MR AC and semi-quantitative segmental (20-segment model) myocardial tracer uptake (per cent of maximum) and compared to PET/CT which was reconstructed using CT AC and served as standard of reference. Excellent correlations were found for regional uptake values between PET/CT and PET/MRI with TOF (n = 460 segments in 23 patients; r = 0.913; p < 0.0001) with narrow Bland-Altman limits of agreement (-8.5 to +12.6 %). Correlation coefficients were slightly lower between PET/CT and PET/MRI without TOF (n = 460 segments in 23 patients; r = 0.851; p < 0.0001) with broader Bland-Altman limits of agreement (-12.5 to +15.0 %). PET/MRI with and without TOF showed minimal underestimation of tracer uptake (-2.08 and -1.29 %, respectively), compared to PET/CT. Relative myocardial FDG uptake obtained from MR-based attenuation corrected FDG PET is highly comparable to standard CT-based attenuation corrected FDG PET, suggesting interchangeability of both AC techniques. (orig.)

18F-FDG PET/CT findings of sinonasal inverted papilloma with or without coexistent malignancy: comparison with MR imaging findings in eight patients

International Nuclear Information System (INIS)

Yeon Jeon, Tae; Kim, Hyung-Jin; Lee, In Ho; Kim, Sung Tae; Jeon, Pyoung; Kim, Keon Ha; Byun, Hong Sik; Choi, Joon Young

2009-01-01

Sinonasal inverted papilloma (IP) is known for high rate of associated malignancy. The purpose of this study was to identify 18 F-FDG PET/CT findings of sinonasal IPs. We also tried to compare the PET/CT findings with the MR imaging findings. We retrospectively reviewed PET/CT and MR images of eight patients with sinonasal IP with (n = 6) or without (n = 2) coexistent squamous cell carcinoma (SCC). Particular attention was paid to correlate the PET/CT findings with the MR imaging findings in terms of area distribution of standard uptake values (SUVs) and a convoluted cerebriform pattern (CCP). In two benign IPs, the maximum SUVs measured 8.2 and 7.8, respectively (mean, 8.0). In both tumors, MR images demonstrated a diffuse CCP. In six IPs with coexistent SCC, the maximum SUVs ranged from 13.3 to 31.9 (mean ± SD, 20.2 ± 6.6). In these tumors, MR images demonstrated a diffuse CCP in two, a partial CCP in three, and no CCP in one. A wide discrepancy was noted between MR imaging and PET/CT in terms of area distribution of a CCP and SUVs. In sinonasal lesions with MR imaging features of IP, 18 F-FDG PET/CT demonstrating avid FDG uptake does not necessarily imply the presence of coexistent malignancy. In our small series, although IPs containing foci of SCC had consistently higher SUVs than IPs without SCC, the limited literature on this subject suggests that PET cannot be used reliably to make the distinction. (orig.)

Non-Hodgkin's lymphoma of the nasopharynx: CT and MR imaging

International Nuclear Information System (INIS)

King, A.D.; Lei, K.I.K.; Richards, P.S.; Ahuja, A.T.

2003-01-01

OBJECTIVE: Nasopharyngeal (NP) non-Hodgkin's lymphoma (NHL) is an uncommon tumour. The aim of the study was to describe the appearances on CT and MR imaging, and identify the features which help to distinguish NPNHL from other NP tumours. MATERIALS AND METHODS: The CT (n=8) and MR (n=10) images of 14 patients with NPNHL were reviewed retrospectively. Patients with NPNHL were divided into primary NPNHL, where the primary tumour was in the NP (n=7) and secondary NPNHL where the primary tumour was at another extranodal site in the head and neck (n=7). All NPNHL were assessed for tumour size and distribution, appearance and local tumour invasion, in addition lymphadenopathy was assessed in primary NPNHL. RESULTS: The NPNHL ranged in size from 20-75 mm (mean of 55 mm for primary and 30 mm for secondary NHL) and were homogeneous on CT in eight (100%) and MR in seven (70%) and mildly heterogeneous on MR in three (30%) patients. NPNHL involved all walls of the NP in 10 (71%) and extended in an exophytic fashion to fill the NP cavity in six (43%). Deep tumour invasion was present in two (14%) both patients with primary NHL, the extent and volume of this tumour invasion was small and involved the prevertebral muscles (n=2), parapharyngeal fat space (n=1) and skull base (n=1). Primary NPNHL extended superficially in five (71%) to involve the nasal cavity (n=3) and oropharynx (n=2) and lymphadenopathy was present in five (71%) being bilateral and involving multiple nodal sites (n=4) with necrosis (n=2) and matting (n=3). CONCLUSION: NPNHL is a homogeneous tumour that tends to diffusely involve all walls of the nasopharynx and spread in an exophytic fashion to fill the airway, rather than infiltrating into the deep tissues. Deep tumour infiltration, when it occurs, is found in those patients with primary NHL and is usually limited in extent and of small volume. Primary NHL more commonly spreads superficially to involve the nasal cavity or oropharynx, lymphadenopathy is frequent

CT-guided diagnostic interventions for classification of focal hepatic lesions: A comparison of 14 G- and 18 G-large bore cutting needles; CT-gesteuerte perkutane Biopsien zur Klassifizierung von fokalen Leberlaesionen: Vergleich zwischen 14 G- und 18 G-Stanzbiopsienadeln

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Haage, P.; Piroth, W.; Staatz, G.; Adam, G.; Guenther, R.W. [Klinik fuer Radiologische Diagnostik, Universitaetsklinikum der RWTH Aachen (Germany)

1999-07-01

Purpose: Analysis and comparison of CT-guided 14- and 18-gauge cutting needle biopsies to accurately assess focal liver disease. Methods: The data of 272 CT-guided biopsies in 268 patients were evaluated retrospectively with regard to sensitivity, specificity and complication rate of the chosen needle caliber in differentiating between benign and malignant disease as well as in the ability to determine specific cell types in the various disorders. A 14-gauge (G) needle was used in 101 (37.1%) cases, in 18-g needle biopsy was performed in 171 (62.9%) cases. The Fisher exact test was employed for statistical analysis. Results: Cutting needle biopsy yielded sufficient histologic material in 267 of 272 (98.2%) cases. Correct diagnosis of malignancy was established in 178 of 191 (93.2%) lesions, 73 of 76 (96.1%) disorders were accurately defined as benign, resulting in an overall value of 94.0% (251 of 267). Of these 251 biopsies a definite histological diagnosis could be determined in 90.6% of the cases employing a 14 G needle and in 90.3% using an 18-g needle. The sensitivity, specificity and rate of complications were 94.8%, 92.0%%, 3.0% for the 14-g needle and 92.7%, 97.6%, 0.6% for the 18-g needle, respectively. There were no statistically significant differences with regard to the needle size. Conclusions: CT-guided biopsy of hepatic lesions with the 18-g biopsy needle is of equivalent diagnostic accuracy when compared with the 14-g needle. (orig.) [Deutsch] Ziel: Analyse und Vergleich CT-gesteuerter Fein- und Grobstanzbiopsien zur definitiven Abklaerung unklarer fokaler Leberveraenderungen. Methoden: Die Daten von insgesamt 272 CT-gefuehrten Punktionen an 268 Patienten wurden retrospektiv hinsichtlich Sensitivitaet, Spezifitaet und Komplikationsrate zur Dignitaetsbestimmung und Faehigkeit zur artdiagnostischen Einordnung unter Beruecksichtigung der Groesse der gewaehlten Punktionsnadel ueberprueft und ausgewertet. In 101 (37,1%) Faellen wurde eine 14 Gauge (G

Prospective head-to-head comparison of 11C-choline-PET/MR and 11C-choline-PET/CT for restaging of biochemical recurrent prostate cancer

International Nuclear Information System (INIS)

Eiber, Matthias; Rauscher, Isabel; Souvatzoglou, Michael; Schwaiger, Markus; Maurer, Tobias; Holzapfel, Konstantin; Beer, Ambros J.

2017-01-01

Whole-body integrated 11 C-choline PET/MR might provide advantages compared to 11 C-choline PET/CT for restaging of prostate cancer (PC) due to the high soft-tissue contrast and the use of multiparametric MRI, especially for detection of local recurrence and bone metastases. Ninety-four patients with recurrent PC underwent a single-injection/dual-imaging protocol with contrast-enhanced PET/CT followed by fully diagnostic PET/MR. Imaging datasets were read separately by two reader teams (team 1 and 2) assessing the presence of local recurrence, lymph node and bone metastases in predefined regions using a five-point scale. Detection rates were calculated. The diagnostic performance of PET/CT vs. PET/MR was compared using ROC analysis. Inter-observer and inter-modality variability, radiation exposure, and mean imaging time were evaluated. Clinical follow-up, imaging, and/or histopathology served as standard of reference (SOR). Seventy-five patients qualified for the final image analysis. A total of 188 regions were regarded as positive: local recurrence in 37 patients, 87 regions with lymph node metastases, and 64 regions with bone metastases. Mean detection rate between both readers teams for PET/MR was 84.7% compared to 77.3% for PET/CT (p > 0.05). Local recurrence was identified significantly more often in PET/MR compared to PET/CT by team 1. Lymph node and bone metastases were identified significantly more often in PET/CT compared to PET/MR by both teams. However, this difference was not present in the subgroup of patients with PSA values ≤2 ng/ml. Inter-modality and inter-observer agreement (K > 0.6) was moderate to substantial for nearly all categories. Mean reduction of radiation exposure for PET/MR compared to PET/CT was 79.7% (range, 72.6-86.2%). Mean imaging time for PET/CT was substantially lower (18.4 ± 0.7 min) compared to PET/MR (50.4 ± 7.9 min). 11 C-choline PET/MR is a robust imaging modality for restaging biochemical recurrent PC and

Bilateral subacromial bursitis with macroscopic rice bodies: Ultrasound, CT and MR appearance

International Nuclear Information System (INIS)

Law, T.C.; Chong, S.F.; Lu, P.P.; Mak, K.H.

1998-01-01

The radiological findings of ultrasound, CT and MR of a case of bilateral subacromial bursitis with macroscopic rice bodies is described. MRI is the investigation of choice and the intravenous gadolinium-enhanced usefulness was noted. The previous literature is also reviewed. Copyright (1998) Blackwell Science Pty Ltd

Assessment of hemodynamic changes in patients with renal artery stenosis by means of the cine MR phase-contrast technique; Einstufung haemodynamischer Veraenderungen bei Nierenarterienstenosen mittels MR-Cine-Phasenkontrastflussmessungen

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Schoenberg, S.O.; Knopp, M.V.; Bock, M.; Essig, M.; Hawighorst, H.; Zuna, I.; Schad, L.; Kaick, G. van [Deutsches Krebsforschungszentrum, Heidelberg (Germany). Forschungsschwerpunkt Radiologische Diagnostik und Therapie; Kallinowski, F.; Allenberg, J.R. [Chirurgische Universitaetsklinik, Heidelberg (Germany). Sektion Gefaesschirurgie; Just, A. [Heidelberg Univ. (Germany). 1. Physiologisches Inst.

1997-08-01

Purpose: To evaluate the use of high-temporal resolution cine MR phase-contrast flow measurements for assessment of flow dynamics in renal artery stenosis (RAS). Material and methods: In a dog model, cine MR flow measurements were validated by comparing the MR flow data to an invasive transit-time ultrasound reference technique for different degrees of RAS. Cardiac-gated MR flow curves were recorded in 56 renal arteries of 28 patients with a temporal resolution of at least 32 ms. In all cases RAS was confirmed by digital subtraction angiography (DSA). Abnormalities of flow dynamics were assessed in the calculated flow curves using the MR parameters mean flow, maximum velocity, and time to systolic maximum. Results: By means of the MR blood flow paremeters high-grade stenoses (>50%, n=23) were detected with sensitivity of 100% and specificity of 94% with reference to DSA. The overall differentiation between stenoses (n=37) and non-stenosed vessels (n=19) revealed a sensitivity of 87% and a specificity of 100%. Conclusion: Analysis of cardiac-gated MR flow curves provides a non-invasive method to assess the hemodynamic significance of RAS and thus allows a functional evaluation in relation to the morphologic characteristics of the stenosis. (orig.) [Deutsch] Ziel der Untersuchung war die Beurteilung der Haemodynamik bei Nierenarterienstenosen mittels Cine-MR-Phasenkontrastflussmessungen. In einem Hundemodell wurde die Cine-MR-Flussmessung validiert, indem fuer unterschiedliche Stenosegrade Vergleichsmessungen mit einer invasiven Transitzeit-Ultraschallreferenztechnik durchgefuehrt wurden. EKG-getriggerte MR-Flusskurven wurden bei 28 Patienten in 56 Nierenarterien mit einer Zeitaufloesung von mindestens 32 ms aufgenommen. Alle Nierenarterienstenosen wurden mittels digitaler Subtraktionsangiographie gesichert. Stoerungen in der renalen Haemodynamik wurden anhand der berechneten MR-Flusskurven mit Hilfe der Parameter `Mittelfluss, `maximale Geschwindigkeit` und `Zeit

MELAS syndrome in a child: CT and MR findings

International Nuclear Information System (INIS)

Choi, Bye Young; Hong, Soo Jong; Cho, Jeong Hee; Suh, Dae Chul; Hong, Chang Yee

1993-01-01

MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) is one of the mitochondrial encephalomyopathy, A rare disease caused by a disturbance of the mitochondrial chain of respiration. MELAS is confirmed by typical light and electron microscopic findings: 'ragged red fibers' by modified Gomori trichrome stain on light microscope and numerous abnormal mitochondria on electron microscope. We experienced a boy with the characteristic clinical and pathologic findings of MELAS. Our patient demonstrated bilateral basal ganglia calcifications and infarction at right parieto-occipital and thalamic areas on CT and MR. We found that MRI was more sensitive and represented the infarcted lesions better than CT. Detection of cerebral insults of MELAS by MRI is important in making decision on patient treatment and also in prediction of the patient prognosis

Multislice helical CT (MSCT) for mid-facial trauma: optimization of parameters for scanning and reconstruction; Mehrschicht-Spiral-CT (MSCT) beim Mittelgesichtstrauma: Optimierung der Aufnahme- und Rekonstruktionsparameter

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Dammert, S.; Funke, M.; Obernauer, S.; Grabbe, E. [Abt. Roentgendiagnostik I, Georg-August-Univ. Goettingen (Germany); Merten, H.A. [Abt. fuer Mund-, Kiefer- und Gesichtschirurgie, Georg-August-Univ. Goettingen (Germany)

2002-07-01

Purpose: To determine the optimal scan parameters in multislice helical CT (MSCT) of the facial bone complex for both axial scanning and multiplanar reconstructions. Material and Methods: An anthropomorphic skull phantom was examined with a MSCT. Axial scans were performed with continuously increasing collimations (4 x 1.25 - 4 x 2.5 mm), tube current (20 - 200 mA) and table speeds (3.75 mm/rot. and 7.5 mm/rot.). Multiplanar reconstructions in coronal and parasagittal planes with different reconstruction increment and slice thickness were evaluated in terms of image noise, contour artifacts and visualisation of anatomical structures. Results: The best image quality was obtained with a collimation of 4 x 1.25 mm and a - table speed of 3.75 mm/rot. A reconstruction increment of 0.6 mm achieved the best time to image quality relation. With these parameters the bone structures were depicted in an optimal way without artifacts. The tube current could be reduced to 50 mA without significant loss of image quality. The optimized protocol was used for regular routine examinations in patients with facial trauma (n = 66). Conclusions: Low-dose MSCT using thin collimation, low table speed and small reconstruction increments provides excellent data for both axial images and multiplanar reconstructions in patients with facial trauma. An additional examination in coronal orientation is therefore no longer necessary. (orig.) [German] Zielsetzung: Verbesserung der Aufnahme- und Rekonstruktionsparameter in der Mehrschicht Spiral-CT (MSCT) zur Untersuchung des knoechernen Mittelgesichtes in verschiedenen Ebenen. Material und Methode: Ein anthropomorphes Schaedel-Phantom wurde in axialer Schichtfuehrung mit einem MSCT untersucht, wobei die Kollimation (1,25 - 2,5 mm), der Tischvorschubfaktor (Pitch 3 - 6) und der Roehrenstrom (20 - 200 mA) systematisch variiert wurden. Aus den Volumendatensaetzen wurden jeweils koronare und parasagittale Sekundaerreformationen mit unterschiedlichen

31P MR spectroscopic imaging in preoperative embolization therapy of meningiomas; Phosphor-31-MR-spektroskopische Bildgebung bei praeoperativer Embolisationstherapie von Meningeomen

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Blankenhorn, M. [Psychiatrische Universitaetsklinik, Ulm (Germany). Abteilung III; Bachert, P.; Kaick, G. van [Deutsches Krebsforschungszentrum Heidelberg (Germany). Forschungsschwerpunkt Radiologische Diagnostik; Semmler, W. [Freie Univ. Berlin (Germany). Inst. fuer Diagnostikforschung; Ende, G. [Zentralinstitut fuer Seelische Gesundheit, Mannheim (Germany). NMR-Forschung in der Psychiatrie; Tronnier, V. [Neurochirurgische Klinik, Klinikum der Universitaet, Heidelberg (Germany); Sartor, K. [Neurologische Klinik, Klinikum der Universitaet, Heidelberg (Germany). Abt. Neuroradiologie

1999-06-01

Purpose: {sup 31}P MR spectroscopic imaging ({sup 31}P SI) was evaluated in a clinical study as a method for monitoring presurgical devascularization of meningiomas. The aim was to assess noninvasively metabolic alterations in tumor and in healthy brain tissue before and after embolization. Methods: Localized {sup 31}P MR spectra of the brain were obtained by means of 2D-SI (voxel size: 36 cm{sup 3}) using a 1,5-T whole-body MR tomograph. Results: Eleven of 19 patients with intracranial meningiomas examined in this study underwent preoperative embolization therapy; eight patients were examined before and after treatment. After embolization, alterations of pH and of the concentrations of high-energy phosphates (nucleoside-5`triphosphate=NTP, phosphocreatine=PCr), inorganic phosphate (P{sub i}), and membrane constituents were observed in the tumors. A tendency of [P{sub i}] increase and decrease of [NTP], [PCr], and pH predominated, which is explained by ischemic processes after tumor devascularization. Conclusion: {sup 31}P SI is applicable in clinical studies and detects alterations of phosphate metabolism in a meningioma after embolization. (orig.) [Deutsch] Ziel: Die {sup 31}P-MR-spektroskopische Bildgebung ({sup 31}P-SI) wurde im Rahmen der praeoperativen Embolisationstherapie von Patienten mit Meningeomen als Methode zur Therapieverlaufskontrolle klinisch geprueft. Ziel der Studie war die nichtinvasive Erfassung von Veraenderungen im Metabolismus der Tumoren vor und nach Embolisation im Vergleich zum gesunden Hirngewebe. Methoden: Lokalisierte {sup 31}P-MR-Spektren des Gehirns wurden mit 2D-SI (Voxelgroesse: 36 cm{sup 3}) an einem 1,5-T-Ganzkoerper-MR-Tomographen aufgenommen. Ergebnisse: Elf von insgesamt 19 untersuchten Patienten unterzogen sich einer praeoperativen Embolisation, bei acht Patienten konnte eine Verlaufskontrolle durchgefuehrt werden. Nach Embolisation wurden Veraenderungen des pH und der Konzentrationen von energiereichen Phosphaten (Nukleosid

CT and MR imaging of post-aortic left brachiocephalic vein

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Amano, Yasuo; Takagi, Ryo; Hayashi, Hiromitsu; Kumazaki, Tatsuo (Nippon Medical School, Tokyo (Japan))

1993-10-01

The usefulness of CT and MR imaging (MRI) for the diagnosis of post-aortic left brachiocephalic vein (PALBV) is discussed. The subjects of the present study consisted of five patients with PALBV, two males and three females, aged for months to sixty years. Chest CT and MRI were performed as a follow-up study of other intrathoracic lesions in two cases, and for further examination of congenital heart diseases in two infant cases. The other patient underwent both CT and MRI to evaluate sporadic chest pain. Therefore, all PALBV were found incidentally. PALBV passes below the aortic arch in front of the trachea, draining the superior vena cava behind the ascending aorta. The finding was particularly well documented on consecutive coronal sections on MRI. In patients with intrathoracic malignant or specific inflammatory lesion, differentiation between PALBV and lymphadenopathy is necessary for treatment. From our experience, marked enhancement on CT and no signal intensity on MRI in PALBV could differentiate this anomaly from mediastinal lymphadenopathy. In two infantile cases with congenital cardiovascular anomalies such as tetralogy of Fallot, right aortic arch and pulmonary arterial stenosis, MRI was found to be superior to CT in demonstrating these anomalies. (author).

CT and MR imaging of post-aortic left brachiocephalic vein

International Nuclear Information System (INIS)

Amano, Yasuo; Takagi, Ryo; Hayashi, Hiromitsu; Kumazaki, Tatsuo

1993-01-01

The usefulness of CT and MR imaging (MRI) for the diagnosis of post-aortic left brachiocephalic vein (PALBV) is discussed. The subjects of the present study consisted of five patients with PALBV, two males and three females, aged for months to sixty years. Chest CT and MRI were performed as a follow-up study of other intrathoracic lesions in two cases, and for further examination of congenital heart diseases in two infant cases. The other patient underwent both CT and MRI to evaluate sporadic chest pain. Therefore, all PALBV were found incidentally. PALBV passes below the aortic arch in front of the trachea, draining the superior vena cava behind the ascending aorta. The finding was particularly well documented on consecutive coronal sections on MRI. In patients with intrathoracic malignant or specific inflammatory lesion, differentiation between PALBV and lymphadenopathy is necessary for treatment. From our experience, marked enhancement on CT and no signal intensity on MRI in PALBV could differentiate this anomaly from mediastinal lymphadenopathy. In two infantile cases with congenital cardiovascular anomalies such as tetralogy of Fallot, right aortic arch and pulmonary arterial stenosis, MRI was found to be superior to CT in demonstrating these anomalies. (author)

Rise of the machines : cyclotrons and radiopharmaceuticals in the PET-CT-MR golden age

International Nuclear Information System (INIS)

Price, Roger

2011-01-01

Full text: One particularly inspiring narrative in the evolution of medical imaging over 35 years begins with the introduction of quassi-routine production of 18F, enabled by advances in reliability of (medical) cyclotrons; invention of the 'molecule of the century' [18F]FOG and its robust synthesis; comprehending betrayal of major tumour-cell types by their glucose avidity; astounding advances in PET scanners (recently, time-of-flight); and marriage of anatomic with functional 3-D imaging as PET/CT or (recently) PET/MR. Though the explosion in PET is identified historically with diagnostic oncology plus quantitation of nuclear medicine, plus the collateral leverage of advances in CT and MR, other potentially transformative opportunities (pre-diagnosis or quantifying treatment response) are emerging in dementia and diabetes-as exemplars of PET-addressable mass afflictions-driven by advances in specificity/sensitivity of targeting molecules. PET delivers femto-M functional sensitivity (e.g.; receptor-targeting)-several magnitude-orders of narrow-context superiority over MR or CT-exemplified by the rapid rise of solid-targetry metallo-PET (64Cu, 89Zr), and concomitantly, preclinical radioimmuno micro-PET/CT/SPECT imaging. Though [11 C ] PET has elucidated brain, prostate and other cell +/- tumour mechanisms, realistic clinical rollout demands longer halflife [18F]-labelling. [18F] innovations beyond [18F]FDG elucidate numerous metabolisms, including choline, hypoxia, apoptosis and amino-acid, and notably will soon provide a routine-clinical [18F]-alternative to [11 C] based beta-amyloid dementia diagnosis. Frontier PET is constrained by cost/dose, shackled to 'twentieth century' technologies-cyclotron, hotcell and synthesis unit. Example is [18F] bone scintigraphy; acknowledged as clinically superior to [99mTc]MOP, its widespread implementation awaits cheaper isotope, accessible PET/CT scanners, and maybe 'true' shortage of [99mTc]. Generator-sourced 68 Ga-PET is

A 3D active shape model driven by fuzzy inference : application to cardiac CT and MR

NARCIS (Netherlands)

Assen, van H.C.; Danilouchkine, M.G.; Dirksen, M.S.; Reiber, J.H.C.; Lelieveldt, B.P.F.

2008-01-01

Abstract—Manual quantitative analysis of cardiac left ventricular function using Multislice CT and MR is arduous because of the large data volume. In this paper, we present a 3-D active shape model (ASM) for semiautomatic segmentation of cardiac CT and MRvolumes, without the requirement of

Fibrous soft tissue tumor of neck and shoulder girdle: MR and CT characteristics

International Nuclear Information System (INIS)

Gu Yajia; Peng Weijun; Wang Peihua; Wang Jian

2005-01-01

Objective: To evaluate MR and CT imagings of desmoplastic fibroblastoma (DF) and aggressive fibromatosis (AF) in neck and shoulder girdle, and to emphasis upon the MRI findings with pathological correlation. Methods: MR and CT appearances of DFs (4 cases) and AFS (3 cases) confirmed by surgical and pathologic findings were retrospective analysed, which were correlated to the pathologic features. Four cases of DF were male patients, with a median age at 48 years. Two cases of AF were female (20, 29 years respectively), and another AF patient was male (79 years). Results: (1) Four DFs were round mass located in the inter muscle space of neck, and the margins were mostly well-circumscribed. Envelope was seen in one lesion on MRI. On unenhanced CT, the masses showed homogeneous low attenuation (2 cases) or slightly low attenuation with several heterogeneous areas in it (1 cases). Enhancement was not obvious on post-contrast CT images. MRI studies were done in two patients. Signal intensity (SI) on MR was homogeneous and heterogeneous one lesion respectively on unenhanced T 1 -weighted images. Mixed SI as low or high SI nodes within isointense compared with muscle on T 2 -weighted images. No evident enhancing was noted after administration of gadopentetate dimeglumine. (2) All three lesions of aggressive fibromatosis arose from musculoaponeurotic structures. The masses were irregular margin and appeared elongated, which oriented in the direction of the muscle bundle. On unenhanced CT examination, the masses had poorly defined and isodense relative to adjacent musculature (2 cases). On T 1 -weighted images, three masses consisted of poormargination and isointensity relative to adjacent muscle. On T 2 -weighted images, two lesions were heterogeneity of signal, which predominantly slightly high in SI with strip-or node-shape low SI, and one lesion had homogeneous high SI. On post-contrast T 1 -weighted images, all lesions showed marked enhancement, heterogeneity of signal

Image postprocessing of aortic CTA and MRA; Aktuelle Bildnachverarbeitung der aortalen CTA und MRA

Energy Technology Data Exchange (ETDEWEB)

Tengg-Kobligk, H. von; Weber, T.F.; Rengier, F.; Kauczor, H.U. [Deutsches Krebsforschungszentrum (DKFZ), Abteilung Radiologie E010, Heidelberg (Germany); Boeckler, D. [Ruprecht-Karls-Universitaet Heidelberg, Klinik fuer Gefaesschirurgie, vaskulaere und endovaskulaere Chrirurgie, Heidelberg (Germany); Schumacher, H. [Klinikum der Stadt Hanau, Klinik fuer Gefaesschirurgie, Hanau (Germany)

2007-11-15

Multiplanar reformation (MPR) is the most relevant tool for patient selection and precise procedural planning and also for analyzing postinterventional complications. Curved MPR is used primarily for semiautomated or completely automated calculation of the centerline of the vascular lumen and to estimate the orthogonal vessel diameter and longitudinal extent. Reproducible and accurate measurement of complex pathologies and courses of vessels extends the range of diagnostic radiology. Contemporary scanner consoles allow automated processing of maximum intensity projections (MIP) and standard MPR and their storage in PACS. To improve patient selection, procedural planning, root-cause analysis postoperatively for assessment of treatment effects and to make better communication of findings to nonradiologists possible, volume rendering techniques (VRT) are a beneficial adjunct to source images. With current algorithms semiautomated segmentation is satisfactory for vessels and bones, but not for low-contrast structures (soft tissues), which still need to be segmented manually. In general, isotropic CT source data are preferable to MR images, which are often anisotropic. In many European countries image postprocessing is still not adequately reimbursed although the doctors making referrals often specifically and emphatically demand 3D visualization and measurements in daily practice. (orig.) [German] Die multiplanare Reformatierung (MPR) der Bilddaten aortaler CTA und MRA ist die wichtigste Rekonstruktionsmethode im Hinblick auf eine differenzierte Therapieentscheidung und die praeoperative Therapieplanung sowie die Beschreibung postoperativer Komplikationen. Die gekruemmte MPR wird semiautomatisch bzw. vollstaendig automatisch als Centerline im Gefaesslumen berechnet und fuer die Bestimmung des orthogonalen Durchmessers und der Laengsausdehnung der Pathologie verwendet. Eine reproduzierbar exakte Ausmessung komplexer Pathologien und Gefaesslaengsverlaeufe erweitert das

Multifunctional dendrimer-based nanoparticles for in vivo MR/CT dual-modal molecular imaging of breast cancer

Directory of Open Access Journals (Sweden)

Li K

2013-07-01

Full Text Available Kangan Li,1,4,5,* Shihui Wen,2,* Andrew C Larson,4,5 Mingwu Shen,2 Zhuoli Zhang,4,5 Qian Chen,3 Xiangyang Shi,2,3 Guixiang Zhang1 1Department of Radiology, Shanghai First People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China; 2College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China; 3State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai, People’s Republic of China; 4Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, USA; 5Robert H Lurie Comprehensive Cancer Center, Chicago, IL, USA *These authors contributed equally to this work Abstract: Development of dual-mode or multi-mode imaging contrast agents is important for accurate and self-confirmatory diagnosis of cancer. We report a new multifunctional, dendrimer-based gold nanoparticle (AuNP as a dual-modality contrast agent for magnetic resonance (MR/computed tomography (CT imaging of breast cancer cells in vitro and in vivo. In this study, amine-terminated generation 5 poly(amidoamine dendrimers modified with gadolinium chelate (DOTA-NHS and polyethylene glycol monomethyl ether were used as templates to synthesize AuNPs, followed by Gd(III chelation and acetylation of the remaining dendrimer terminal amine groups; multifunctional dendrimer-entrapped AuNPs (Gd-Au DENPs were formed. The formed Gd-Au DENPs were used for both in vitro and in vivo MR/CT imaging of human MCF-7 cancer cells. Both MR and CT images demonstrate that MCF-7 cells and the xenograft tumor model can be effectively imaged. The Gd-Au DENPs uptake, mainly in the cell cytoplasm, was confirmed by transmission electron microscopy. The cell cytotoxicity assay, cell morphology observation, and flow cytometry show that the developed Gd-Au DENPs have good biocompatibility in the given concentration range. Our results

Neuronavigation accuracy dependence on CT and MR imaging parameters: a phantom-based study

International Nuclear Information System (INIS)

Poggi, S; Pallotta, S; Russo, S; Gallina, P; Torresin, A; Bucciolini, M

2003-01-01

Clinical benefits from neuronavigation are well established. However, the complexity of its technical environment requires a careful evaluation of different types of errors. In this work, a detailed phantom study which investigates the accuracy in a neuronavigation procedure is presented. The dependence on many different imaging parameters, such as field of view, slice thickness and different kind of sequences (sequential and spiral for CT, T1-weighted and T2-weighted for MRI), is quantified. Moreover, data based on CT images are compared to those based on MR images, taking into account MRI distortion. Finally, the contributions to global accuracy coming from image acquisition, registration and navigation itself are discussed. Results demonstrate the importance of imaging accuracy. Procedures based on CT proved to be more accurate than procedures based on MRI. In the former, values from 2 to 2.5 mm are obtained for 95% fractiles of cumulative distribution of Euclidean distances between the intended target and the reached one while, in the latter, the measured values range from 3 to 4 mm. The absence of imaging distortion proved to be crucial for registration accuracy in MR-based procedures

PET-CT and PET-MRI of the prostate. From {sup 18}F-FDG to {sup 68}Ga-PSMA; PET-CT/-MRT der Prostata. Von {sup 18}F-FDG zu {sup 68}Ga-PSMA

Energy Technology Data Exchange (ETDEWEB)

Knorr, K.; Eiber, M.; Scheidhauer, K. [Technische Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Muenchen (Germany); Maurer, T. [Technische Universitaet Muenchen, Urologische Klinik und Poliklinik, Klinikum rechts der Isar, Muenchen (Germany); Wester, H.J. [Technische Universitaet Muenchen, Pharmazeutische Radiochemie, Garching (Germany)

2017-08-15

Fluordesoxyglukose (FDG) ist wegen der biologischen Besonderheiten des Prostatakarzinoms nur bei entdifferenzierten Tumoren hilfreich. Radiopharmaka wie Cholin-Derivate, das beim Prostatakarzinom vermehrt in die Tumorzelle aufgenommen und in die Zellmembran eingebaut wird sowie in juengster Zeit die hochspezifischen Liganden fuer das prostataspezifische Membranantigen (PSMA) revolutionieren derzeit die Prostatakarzinombildgebung und das (Re-)Staging. {sup 68}Ga-markierte PSMA-Liganden fuer PET-CT und PET-MRT sind hochspezifische Tracer zur Primaerdiagnostik sowie zur Lokalisationsdiagnostik im biochemischen Rezidiv eines Prostatakarzinoms. Bei Risikopatienten, also Patienten mit Intermediate- und High-risk-Tumoren haben sie die cholinbasierte PET-CT weitgehend verdraengt, insbesondere auch bei sehr niedrigen PSA-Werten (prostataspezifisches Antigen) von <0,5 ng/ml in der Rezidivdiagnostik. Die Anwendung bei der Primaerdiagnostik als PET-MRT, auch in Kombination mit der multiparametrischen MRT (mpMR), ist vielversprechend bzgl. der Fruehdiagnostik und der bildfusionsgestuetzten Biopsie sowie zur Operations- und Bestrahlungsplanung. (orig.)

Bias atlases for segmentation-based PET attenuation correction using PET-CT and MR.

Science.gov (United States)

Ouyang, Jinsong; Chun, Se Young; Petibon, Yoann; Bonab, Ali A; Alpert, Nathaniel; Fakhri, Georges El

2013-10-01

This study was to obtain voxel-wise PET accuracy and precision using tissue-segmentation for attenuation correction. We applied multiple thresholds to the CTs of 23 patients to classify tissues. For six of the 23 patients, MR images were also acquired. The MR fat/in-phase ratio images were used for fat segmentation. Segmented tissue classes were used to create attenuation maps, which were used for attenuation correction in PET reconstruction. PET bias images were then computed using the PET reconstructed with the original CT as the reference. We registered the CTs for all the patients and transformed the corresponding bias images accordingly. We then obtained the mean and standard deviation bias atlas using all the registered bias images. Our CT-based study shows that four-class segmentation (air, lungs, fat, other tissues), which is available on most PET-MR scanners, yields 15.1%, 4.1%, 6.6%, and 12.9% RMSE bias in lungs, fat, non-fat soft-tissues, and bones, respectively. An accurate fat identification is achievable using fat/in-phase MR images. Furthermore, we have found that three-class segmentation (air, lungs, other tissues) yields less than 5% standard deviation of bias within the heart, liver, and kidneys. This implies that three-class segmentation can be sufficient to achieve small variation of bias for imaging these three organs. Finally, we have found that inter- and intra-patient lung density variations contribute almost equally to the overall standard deviation of bias within the lungs.

An experimental study of exogenous lipoid pneumonia : sequential changes in high-resolution CT and MR findings

International Nuclear Information System (INIS)

Kim, Kyeong Ah; Kang, Eun Young; Kim, Dae Hyun; Park, Sang Woo; Choi, Jeong Cheol; Kim, Ae Ree; Kim, Han Kyum; Cha, In Ho

1999-01-01

To evaluate sequential changes in high-resolution CT(HRCT) and MR findings of exogenous lipoid pneumonia in rabbits and to compare the radiologic and histopathologic findings. A single endobronchial administration of shark liver oil(0.5 or 1 ml/kg of body weight) was given to 25 rabbits. HRCT scans were obtained immediately(n=17), at 1 day(n=14), 3 days(n=10), 1 week(n=15), 2 weeks(n=10), 4 weeks(n=9), 6 weeks(n=5), 8 weeks(n=6), 10 weeks(n=4), 12 weeks(n=2), 14 weeks(n=3), and 16 weeks(n=2) after administration. Changes in distribution, extent, and attenuation were assessed on HRCT scans. MR scans were obtained immediately(n=12), at 1 day(n=9), 3 days(n=9), 1 week(n=15), 2 weeks(n=9), 4 weeks(n=11), 6 weeks(n=5), 8 weeks(n=7), 10 weeks(n=3), 14 weeks(n=3), and at 16 weeks(n=2) after administration. Changes in distribution, extent, and signal intensity were assessed on MR scans. In 16 rabbits, CT and MR findings were compared with histopatholo-gic findings obtained in the same plane. HRCT findings included consolidation with air-bronchogram, ground-glass attenuation and fat attenuation within the lesion at earlier stages(immediate-2 weeks). The extent of lesions was greatest at 1 week, and was then seen to gradually decrease on follow-up CT scans. T1-weighted MR images(T1WI) showed high or intermediate signal intensity(SI) at earlier stages and intermediate SI at later stages, while T2-weighted MR images(T2WI) showed high SI at both earlier and later stages. Histopathologic correlation showed that ground-glass attenuation and consolidation on HRCT reflected intraalveolar lipid-laden macrophages, cuboidal metaplasia of alveolar epithelial cells, and alveolar septal widening with inflammatory cell infiltration. Maximal infiltration of oil in the lung correlated closely with the peak low-attenuation seen on CT scans and the high signal intensity seen on T1WI. Shark liver oil-induced exogenous lipoid pneumonia in rabbits is reliably diagnosed by HRCT and MR during

Cirrhosis: CT and MR imaging evaluation

International Nuclear Information System (INIS)

Brancatelli, Giuseppe; Federle, Michael P.; Ambrosini, Roberta; Lagalla, Roberto; Carriero, Alessandro; Midiri, Massimo; Vilgrain, Valerie

2007-01-01

In this article, we present the CT and MR imaging characteristics of the cirrhotic liver. We describe the altered liver morphology in different forms of viral, alcoholic and autoimmune end-stage liver disease. We present the spectrum of imaging findings in portal hypertension, such as splenomegaly, ascites and varices. We describe the patchy and lacelike patterns of fibrosis, along with the focal confluent form. The process of hepatocarcinogenesis is detailed, from regenerative to dysplastic nodules to overt hepatocellular carcinoma. Different types of non-neoplastic focal liver lesions occurring in the cirrhotic liver are discussed, including arterially enhancing nodules, hemangiomas and peribiliary cysts. We show different conditions causing liver morphology changes that can mimic cirrhosis, such as congenital hepatic fibrosis, 'pseudo-cirrhosis' due to breast metastases treated with chemotherapy, Budd-Chiari syndrome, sarcoidosis and cavernous transformation of the portal vein

Cirrhosis: CT and MR imaging evaluation

Energy Technology Data Exchange (ETDEWEB)

Brancatelli, Giuseppe [Sezione di Radiologia, Ospedale Specializzato in Gastroenterologia, ' Saverio de Bellis' -IRCCS, 70013 Castellana Grotte (Bari) (Italy) and Sezione di Scienze Radiologiche, Dipartimento di Biotecnologie Mediche e Medicina Legale, Universita di Palermo, Via del Vespro 127, 90127 Palermo (Italy) and Department of Radiology, University of Pittsburgh Medical Center, 200 Lothrop Street, 15213 Pittsburgh, PA (United States)]. E-mail: gbranca@yahoo.com; Federle, Michael P. [Department of Radiology, University of Pittsburgh Medical Center, 200 Lothrop Street, 15213 Pittsburgh, PA (United States); Ambrosini, Roberta [Department of Diagnostic and Interventional Radiology, ' Maggiore della Carita' University Hospital, ' A.Avogadro' Eastern Piemonte University, Corso Mazzini 18, Novara (Italy); Lagalla, Roberto [Sezione di Scienze Radiologiche, Dipartimento di Biotecnologie Mediche e Medicina Legale, Universita di Palermo, Via del Vespro 127, 90127 Palermo (Italy); Carriero, Alessandro [Department of Diagnostic and Interventional Radiology, ' Maggiore della Carita' University Hospital, ' A.Avogadro' Eastern Piemonte University, Corso Mazzini 18, Novara (Italy); Midiri, Massimo [Sezione di Scienze Radiologiche, Dipartimento di Biotecnologie Mediche e Medicina Legale, Universita di Palermo, Via del Vespro 127, 90127 Palermo (Italy); Vilgrain, Valerie [Service de Radiologie, Hopital Beaujon, 100 Boulevard du General Leclerc, 92118 Clichy (France)

2007-01-15

In this article, we present the CT and MR imaging characteristics of the cirrhotic liver. We describe the altered liver morphology in different forms of viral, alcoholic and autoimmune end-stage liver disease. We present the spectrum of imaging findings in portal hypertension, such as splenomegaly, ascites and varices. We describe the patchy and lacelike patterns of fibrosis, along with the focal confluent form. The process of hepatocarcinogenesis is detailed, from regenerative to dysplastic nodules to overt hepatocellular carcinoma. Different types of non-neoplastic focal liver lesions occurring in the cirrhotic liver are discussed, including arterially enhancing nodules, hemangiomas and peribiliary cysts. We show different conditions causing liver morphology changes that can mimic cirrhosis, such as congenital hepatic fibrosis, 'pseudo-cirrhosis' due to breast metastases treated with chemotherapy, Budd-Chiari syndrome, sarcoidosis and cavernous transformation of the portal vein.

Bilateral subacromial bursitis with macroscopic rice bodies: Ultrasound, CT and MR appearance

Energy Technology Data Exchange (ETDEWEB)

Law, T.C.; Chong, S.F.; Lu, P.P. [Kwong Wah Hospital (Hong Kong). Department of Radiology; Mak, K.H. [Kwong Wah Hospital (Hong Kong). Department of Orthopaedics and Traumatology

1998-05-01

The radiological findings of ultrasound, CT and MR of a case of bilateral subacromial bursitis with macroscopic rice bodies is described. MRI is the investigation of choice and the intravenous gadolinium-enhanced usefulness was noted. The previous literature is also reviewed. Copyright (1998) Blackwell Science Pty Ltd 5 refs., 1 tab., 4 figs.

Prospective comparison of MR imaging (1.5 T) and CT detection of small intracranial metastases

International Nuclear Information System (INIS)

Dowd, C.F.; Dillon, W.P.; Laxer, K.; Norman, D.; Newton, T.H.

1987-01-01

Prior studies indicate lack of MR imaging sensitivity in the evaluation of intractable seizure patients. The authors reviewed MR imaging studies of 15 patients with intractable seizures. High-quality thin-section multiplanar images were obtained with electrocardiographic gating and/or flow compensation techniques and a 1.5-T General Electric Signa unit. Correlation with intracranial electro-encephalography (EEG), CT, and pathology was obtained in all patients. Abnormalities on MR imaging were detected in all but one patient. Pathology revealed MTS in 12 of 15 patients. Other entities included heterotopias and cavernous angiomas. The authors' study indicates that high-resolution, flow-compensated MR imaging is quite sensitive for localization of eleptogenic structural abnormalities and complements EEG

CT and MR imaging in the evaluation of leptomeningeal metastases

International Nuclear Information System (INIS)

Xiao Jiahe; Wang Dayou; Deng Kaihong

1999-01-01

Objective: To study the manifestations of leptomeningeal metastases on CT and MR imaging, and evaluate the diagnostic significance of both modalities for this disease. Methods: Clinical and neuroradiological data of 21 cases with leptomeningeal metastases were retrospectively reviewed. In this series, 16 patients were studied by CT and 7 patients by MRI, 2 patients by both CT and MRI. Results: Abnormal enhancement of pia and subarachnoid space, appearing as diffuse pattern in 10 cases, nodular pattern in 8 cases and mixed pattern with diffuse plus nodules in 3 cases, were visualized by CE-CT and Gd-MRI. Diffuse enhancement followed the convolutions of gyri and surface of brainstem, and extended into cerebral cisterns and sulci. the foci appeared as enhanced nodules 0.2-3.0 cm in diameter and 1 or more in number. Nodules with infiltration of cerebral parenchymal were found in 4 patients. In 86% of all cases, diffuse or nodular foci occurred in basilar systems and adjacent cerebellar and cerebral sulci. There were 4 cases associated with ependymal nodular enhancement and 10 cases with widened irregular tentorial enhancement. Intracerebral metastases in 9 cases and hydrocephalus in 13 cases were found in this series. Conclusions: CE-CT and Gd-MRI are had significant clinical diagnostic value for leptomeningeal metastases, Gd-MRI is superior to CE-CT. Because of the limitation in the evaluation of leptomeningeal invasion by neoplasms on CT and MRI, definitive diagnosis of leptomeningeal metastases depends on combination of clinical and imaging data

Myositis Ossificans of the Psoas Muscle After Compression Fracture of Lumbar Spine: CT and MR Imaging Findings

International Nuclear Information System (INIS)

Choi, Mi Nyong; Lee, Gyung Kyu; Suh, Kyung Jin

2010-01-01

Myositis ossificans is a benign, self-limiting and non-neoplastic development of heterotopic bone in skeletal muscle following trauma. Although myositis ossificans can occur anywhere in the body, psoas muscle involvement is very rare. To the best of our knowledge, CT and MR imaging findings of myositis ossificans in the psoas muscle secondary to lumbar spine fracture have not been reported in the radiological literature. In this article, we describe the CT and MR imaging findings of myositis ossificans of the psoas muscle after lumbar spine fracture in a 64-year-old man, and conduct a review of the relevant literature

Myositis Ossificans of the Psoas Muscle After Compression Fracture of Lumbar Spine: CT and MR Imaging Findings

Energy Technology Data Exchange (ETDEWEB)

Choi, Mi Nyong; Lee, Gyung Kyu [Hallym University College of Medicine, Hangang Sacred Heart Hospital, Seoul (Korea, Republic of); Suh, Kyung Jin [Dongguk University College of Medicine, Gyungju Hospital, Gyeongju (Korea, Republic of)

2010-02-15

Myositis ossificans is a benign, self-limiting and non-neoplastic development of heterotopic bone in skeletal muscle following trauma. Although myositis ossificans can occur anywhere in the body, psoas muscle involvement is very rare. To the best of our knowledge, CT and MR imaging findings of myositis ossificans in the psoas muscle secondary to lumbar spine fracture have not been reported in the radiological literature. In this article, we describe the CT and MR imaging findings of myositis ossificans of the psoas muscle after lumbar spine fracture in a 64-year-old man, and conduct a review of the relevant literature

Assess PET/MR in diagnosis of disease in comparison with PET/CT

International Nuclear Information System (INIS)

Yan, Jianhua; Lim, Jason Chu-Chern; Loi, Hoi Yin; Totoman, John; Sinha, Arvind Kumar; Quek, Swee Titan; Townsend, David

2015-01-01

The aim of this study is to assess the performance of 18F-FDG whole body PET/MRI in comparison with PET/CT based on SUV. Anatomical location of lesion with Dixon MRI and additional value of advanced MRI technology such as diffusion weighted MR imaging in diagnosis of malignant disease will also be investigated.

MR-guided preoperative localization and percutaneous core biopsy of suspicious breast lesions - experience on the vertically open 0.5 T system; MRT-gestuetzte Markierung und Stanzbiopsie suspekter Mammalaesionen. Moeglichkeiten und Erfahrungen an einem vertikal offenen 0,5-T-System

Energy Technology Data Exchange (ETDEWEB)

Schneider, J.P.; Schulz, T.; Rueger, S.; Schmidt, F.; Kahn, T. [Universitaetsklinikum Leipzig (Germany). Klinik und Poliklinik fuer Diagnostische Radiologie; Horn, L.C. [Inst. fuer Pathologie, Universitaetsklinikum Leipzig (Germany); Leinung, S. [Chirurgische Klinik I, Universitaetsklinikum Leipzig (Germany); Briest, S. [Frauenklinik, Universitaetsklinikum Leipzig (Germany)

2002-01-01

Purpose. To evaluate the feasibility of performing breast interventions in a vertically open 0.5 T MR system (SIGNA SP/i, GE Medical Systems). To develop fitted equipment and to establish preoperative wire localization and percutaneous breast core biopsy as clinical routine procedures. Patients and methods. Initially, we applied a localization method with the patient placed in a sitting position in 31 cases using a single loop coil and a self-developed fixation device. Subsequently, 46 wire localizations and 28 percutaneous core biopsies were carried out in prone patient position using an open breast coil with an integrated biopsy device. The used instruments were either MR-compatible (18 G biopsy needle and localization wire, 14 G coaxial needle, prototype of a 16 G double-shoot gun) or MR-safe (double-shoot gun with 16 G needle). Results. After biopsy we found the needle tip (18 G for a wire localization and 14 G for a percutaneous core biopsy, respectively) placed either within or close to the lesions (<10 mm distance) for all patients. Out of a total of 66 benign lesions and 39 malignant tumors we missed the lesion (12 mm mean diameter, 4-25 mm range) during open biopsy in two cases and obtained a false negative result for one percutaneous biopsy of a 5 mm lesion. Conclusion. Preoperative wire localization and percutaneous core biopsy of suspicious breast lesions demonstrated by MRI can be carried out in a vertically open 0.5 T MR scanner. The degree of accuracy is comparable with that of X-ray or ultrasound-guided procedures. A follow-up has to be performed in cases with a negative biopsy. (orig.) [German] Zielsetzung. In den letzten Jahren wurde eine Vielzahl von Systemen zur praeoperativen Markierung oder Biopsie MRT-suspekter Mammalaesionen vorgestellt. Ziel unserer Untersuchungen war es, Moeglichkeiten solcher Verfahren an einem vertikal offenen 0,5-T-Magneten (SIGNA SP/i, GE Medical Systems) zu entwickeln, zu erproben und in die klinische Routine zu

Teratoma of the posterior fossa CT and MR aspects A case

International Nuclear Information System (INIS)

Pina, J.I.; Feijoo, R.; Lasierra, R.; Medrano, J.; Benito, J.L. de

1994-01-01

The CT and MR findings are reported for a patient diagnosed as having teratoma of the posterior fossa with onset in the form of intracranial hypertension. The objective of this article is to report the detection of the lesion, as well as its origin in the closure defect of the cranial cavity with the formation of a cutaneous fistula, and review the recent literature

Accuracy evaluation of fusion of CT, MR, and SPECT images using commercially available software packages (SRS PLATO and IFS)

International Nuclear Information System (INIS)

Mongioj, Valeria; Brusa, Anna; Loi, Gianfranco; Pignoli, Emanuele; Gramaglia, Alberto; Scorsetti, Marta; Bombardieri, Emilio; Marchesini, Renato

1999-01-01

Purpose: A problem for clinicians is to mentally integrate information from multiple diagnostic sources, such as computed tomography (CT), magnetic resonance (MR), and single photon emission computed tomography (SPECT), whose images give anatomic and metabolic information. Methods and Materials: To combine this different imaging procedure information, and to overlay correspondent slices, we used commercially available software packages (SRS PLATO and IFS). The algorithms utilize a fiducial-based coordinate system (or frame) with 3 N-shaped markers, which allows coordinate transformation of a clinical examination data set (9 spots for each transaxial section) to a stereotactic coordinate system. The N-shaped markers were filled with fluids visible in each modality (gadolinium for MR, calcium chloride for CT, and 99m Tc for SPECT). The frame is relocatable, in the different acquisition modalities, by means of a head holder to which a face mask is fixed so as to immobilize the patient. Position errors due to the algorithms were obtained by evaluating the stereotactic coordinates of five sources detectable in each modality. Results: SPECT and MR position errors due to the algorithms were evaluated with respect to CT: Δx was ≤ 0.9 mm for MR and ≤ 1.4 mm for SPECT, Δy was ≤ 1 mm and ≤ 3 mm for MR and SPECT, respectively. Maximal differences in distance between estimated and actual fiducial centers (geometric mismatch) were in the order of the pixel size (0.8 mm for CT, 1.4 mm for MR, and 1.8 mm for SPECT). In an attempt to distinguish necrosis from residual disease, the image fusion protocol was studied in 35 primary or metastatic brain tumor patients. Conclusions: The image fusion technique has a good degree of accuracy as well as the potential to improve the specificity of tissue identification and the precision of the subsequent treatment planning

Congenital spondylolysis of the cervical spine with spinal cord compression: MR and CT studies

International Nuclear Information System (INIS)

Martinez, M.J.; Marti-Bonmati, L.; Molla, E.; Poyatos, C.; Cerda, E. de la; Urrizola, J.

1997-01-01

Spondylolysis of the cervical spine is a rare disorder that is characterized by a defect in the articular mass between the superior and inferior facets of a cervical vertebra. It is considered to be congenital because it is usually associated with dysplastic changes, especially involving the posterior arch of the vertebra, which differentiates it from its traumatic equivalent. We present two cases of spondylolysis of the cervical spine without spondylolisthesis, which were studied by means of magnetic resonance (MR) and computerized tomography (CT). One patient showed contralateral involvement at two levels and the other had a single lesion presenting canal stenosis with chronic spinal cord compression, an unusual association in previously reported series. the combination of MR and CT makes it possible to limit the spectrum of bone changes and their impact on the spinal cord in these patients. (Author) 12 refs

Diagnostic value of US, CT arthrography, and 0.5-T MR imaging of lesions of the biceps tendon

International Nuclear Information System (INIS)

Saez, F.; Elizagaray, E.; Pena, J.M.; Ferrero, A.; Azkuna, I.; Larrea, L.

1990-01-01

This paper evaluates the role of US, CT-arthrography, and MR imaging in lesions in the tendon of the long head of the biceps brachii and bicipital groove. One hundred fifty-four patients with painful shoulder were prospectively studied by means of US and axial CT-arthrography, and 45 of them were also examined with 0.5-T MR imaging. Fifty-three (34.4%) patients showed biceps tendon or bicipital groove abnormalities; including 34 bicipital groove bone spurs, 31 cases of tendinitis, eight intraarticular ruptures, four subluxations, and eight medial dislocations

Prospective head-to-head comparison of {sup 11}C-choline-PET/MR and {sup 11}C-choline-PET/CT for restaging of biochemical recurrent prostate cancer

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Eiber, Matthias [Klinikum rechts der Isar, Department of Nuclear Medicine, Technische Universitaet Muenchen, Munich (Germany); David Geffen School of Medicine at UCLA, Department of Molecular and Medical Pharmacology, Los Angeles (United States); Rauscher, Isabel; Souvatzoglou, Michael; Schwaiger, Markus [Klinikum rechts der Isar, Department of Nuclear Medicine, Technische Universitaet Muenchen, Munich (Germany); Maurer, Tobias [Klinikum rechts der Isar, Department of Urology, Technische Universitaet Muenchen, Munich (Germany); Holzapfel, Konstantin [Klinikum rechts der Isar, Department of Radiology, Technische Universitaet Muenchen, Munich (Germany); Beer, Ambros J. [Klinikum rechts der Isar, Department of Nuclear Medicine, Technische Universitaet Muenchen, Munich (Germany); Ulm University, Department of Nuclear Medicine, Ulm (Germany)

2017-12-15

Whole-body integrated {sup 11}C-choline PET/MR might provide advantages compared to {sup 11}C-choline PET/CT for restaging of prostate cancer (PC) due to the high soft-tissue contrast and the use of multiparametric MRI, especially for detection of local recurrence and bone metastases. Ninety-four patients with recurrent PC underwent a single-injection/dual-imaging protocol with contrast-enhanced PET/CT followed by fully diagnostic PET/MR. Imaging datasets were read separately by two reader teams (team 1 and 2) assessing the presence of local recurrence, lymph node and bone metastases in predefined regions using a five-point scale. Detection rates were calculated. The diagnostic performance of PET/CT vs. PET/MR was compared using ROC analysis. Inter-observer and inter-modality variability, radiation exposure, and mean imaging time were evaluated. Clinical follow-up, imaging, and/or histopathology served as standard of reference (SOR). Seventy-five patients qualified for the final image analysis. A total of 188 regions were regarded as positive: local recurrence in 37 patients, 87 regions with lymph node metastases, and 64 regions with bone metastases. Mean detection rate between both readers teams for PET/MR was 84.7% compared to 77.3% for PET/CT (p > 0.05). Local recurrence was identified significantly more often in PET/MR compared to PET/CT by team 1. Lymph node and bone metastases were identified significantly more often in PET/CT compared to PET/MR by both teams. However, this difference was not present in the subgroup of patients with PSA values ≤2 ng/ml. Inter-modality and inter-observer agreement (K > 0.6) was moderate to substantial for nearly all categories. Mean reduction of radiation exposure for PET/MR compared to PET/CT was 79.7% (range, 72.6-86.2%). Mean imaging time for PET/CT was substantially lower (18.4 ± 0.7 min) compared to PET/MR (50.4 ± 7.9 min). {sup 11}C-choline PET/MR is a robust imaging modality for restaging biochemical recurrent PC

Real-time interactive three-dimensional display of CT and MR imaging volume data

International Nuclear Information System (INIS)

Yla-Jaaski, J.; Kubler, O.; Kikinis, R.

1987-01-01

Real-time reconstruction of surfaces from CT and MR imaging volume data is demonstrated using a new algorithm and implementation in a parallel computer system. The display algorithm accepts noncubic 16-bit voxels directly as input. Operations such as interpolation, classification by thresholding, depth coding, simple lighting effects, and removal of parts of the volume by clipping planes are all supported on-line. An eight-processor implementation of the algorithm renders surfaces from typical CT data sets in real time to allow interactive rotation of the volume

Characteristic MR and CT imaging findings of hepatobiliary paragonimiasis and their pathologic correlations

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Lu, Chunyan; Hu, Yajun; Chen, Weixia [Dept of Radiology, West China Hospital of Sichuan Univ., Sichuan (China)], e-mail: wxchen25@126.com

2012-06-15

Background: Hepatobiliary paragonimiasis (HP) is not commonly encountered and may be confused with hepatobiliary tumors; however, computed tomography (CT) and magnetic resonance imaging (MRI) features of HP allow this entity to be distinguished from other diseases. Purpose: To present the CT and MRI findings in patients with HP and to describe some specific imaging findings along with their pathological correlations. Material and Methods: Imaging and clinical findings of 21 patients (9 boys/men and 12 girls/women; age range 3-67 years; mean age 40 years) who were diagnosed with HP were retrospectively evaluated. Among these patients, 16 underwent CT examination only, two had MR examination only, and three underwent both CT and MR. All patients underwent surgery, and the HP diagnosis was confirmed by the surgical and histopathologic results. Results: Chronic abdominal pain or back pain was reported by 14 patients, severe abdominal pain with acute onset was reported by one patient, and six patients were asymptomatic and were discovered incidentally. Peripheral eosinophilia was present in 14 patients (14/21, 66.7%), and abnormal liver function tests were found in 16 patients (16/21, 76.2%). Of the 19 patients who underwent CT imaging, 17 patients showed multiple mixed hypodense lesions or multiple cysts with inlaying septation with separate irregular rims or circular enhancement on post-contrast CT images. Tunnel-shaped micro abscesses and necrotic cavities were found in the lesions of 12 of those 17 patients. The other two patients showed smaller cystic masses. MRI showed faveolate T1 hypointense and T2 hyperintense areas in the liver parenchyma with rim or peripheral enhancement. Nodular or circular hyperintense materials were found scattered in the lesions on T1-weighted imaging. Conclusion: CT and MRI can reveal the radiological-pathological features of HP. Together with laboratory findings, MRI and CT findings may provide diagnostic clues, especially in endemic

Characteristic MR and CT imaging findings of hepatobiliary paragonimiasis and their pathologic correlations

International Nuclear Information System (INIS)

Lu, Chunyan; Hu, Yajun; Chen, Weixia

2012-01-01

Background: Hepatobiliary paragonimiasis (HP) is not commonly encountered and may be confused with hepatobiliary tumors; however, computed tomography (CT) and magnetic resonance imaging (MRI) features of HP allow this entity to be distinguished from other diseases. Purpose: To present the CT and MRI findings in patients with HP and to describe some specific imaging findings along with their pathological correlations. Material and Methods: Imaging and clinical findings of 21 patients (9 boys/men and 12 girls/women; age range 3-67 years; mean age 40 years) who were diagnosed with HP were retrospectively evaluated. Among these patients, 16 underwent CT examination only, two had MR examination only, and three underwent both CT and MR. All patients underwent surgery, and the HP diagnosis was confirmed by the surgical and histopathologic results. Results: Chronic abdominal pain or back pain was reported by 14 patients, severe abdominal pain with acute onset was reported by one patient, and six patients were asymptomatic and were discovered incidentally. Peripheral eosinophilia was present in 14 patients (14/21, 66.7%), and abnormal liver function tests were found in 16 patients (16/21, 76.2%). Of the 19 patients who underwent CT imaging, 17 patients showed multiple mixed hypodense lesions or multiple cysts with inlaying septation with separate irregular rims or circular enhancement on post-contrast CT images. Tunnel-shaped micro abscesses and necrotic cavities were found in the lesions of 12 of those 17 patients. The other two patients showed smaller cystic masses. MRI showed faveolate T1 hypointense and T2 hyperintense areas in the liver parenchyma with rim or peripheral enhancement. Nodular or circular hyperintense materials were found scattered in the lesions on T1-weighted imaging. Conclusion: CT and MRI can reveal the radiological-pathological features of HP. Together with laboratory findings, MRI and CT findings may provide diagnostic clues, especially in endemic

MR-CT registration using a Ni-Ti prostate stent in image-guided radiotherapy of prostate cancer.

Science.gov (United States)

Korsager, Anne Sofie; Carl, Jesper; Østergaard, Lasse Riis

2013-06-01

In image-guided radiotherapy of prostate cancer defining the clinical target volume often relies on magnetic resonance (MR). The task of transferring the clinical target volume from MR to standard planning computed tomography (CT) is not trivial due to prostate mobility. In this paper, an automatic local registration approach is proposed based on a newly developed removable Ni-Ti prostate stent. The registration uses the voxel similarity measure mutual information in a two-step approach where the pelvic bones are used to establish an initial registration for the local registration. In a phantom study, the accuracy was measured to 0.97 mm and visual inspection showed accurate registration of all 30 data sets. The consistency of the registration was examined where translation and rotation displacements yield a rotation error of 0.41° ± 0.45° and a translation error of 1.67 ± 2.24 mm. This study demonstrated the feasibility for an automatic local MR-CT registration using the prostate stent.

MR-angiography in vasculitis and benign angiopathy of the central nervous system; MR-Angiographie in der Diagnostik von Vaskulitiden und benignen Angiopathien des Zentralnervensystems

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Schlueter, A.; Hirsch, W.; Jassoy, A.; Behrmann, C.; Spielmann, R.P. [Klinik fuer Diagnostische Radiologie, Martin-Luther-Univ. Halle-Wittenberg (Germany); Kornhuber, M. [Klinik fuer Neurologie, Martin-Luther-Univ. Halle-Wittenberg (Germany); Keysser, G. [Klinik fuer Innere Medizin I, Martin-Luther-Univ. Halle-Wittenberg (Germany)

2001-06-01

To evaluate TOF 3D magnetic resonance angiography (MRA) of the intracranial arteries in patients with vasculitis or vasculitis-like benign angiopathy of the central nervous system (CNS). Method: The results of MRA in 20 patients with clinically and radiographically proven vasculitis (17/20) or vasculitis-like benign angiopathy (3/20) of the CNS were retrospectively analysed. Patients with hyperintense lesions of more than 3 mm on T{sub 2}-weighted MRI images were included in this trial. An inflammatory, embolic, neurodegenerative or metastatic origin of these lesions was excluded by extensive clinical studies. For the MR-examination a TOF 3D FISP sequence was used on a 1.5 T imager. Results: MRA showed characteristic changes for vasculitis or angiopathy in 15 of 20 patients (75%). Conclusions: In patients suspected of having a vasculitis or vasculitis-like angiopathy, MRA is recommended as a non-invasive modality. If the results of MRI and extensive clinical studies are carefully correlated, MRA may substitute conventional angiography in cases with typical vascular changes. (orig.) [German] Ziel der Studie war es, den Wert der TOF 3D Magnetresonanzangiographie (MRA) bei Patienten mit Vaskulitis oder vaskulitisaehnlichen, benignen Angiopathien des Zentralnervensystems (ZNS) zu erfassen. Methoden: Die MRA-Aufnahmen von 20 Patienten mit klinisch und bildgebend nachgewiesener Vaskulitis (17/20) oder vaskulitisaehnlicher, benigner Angiopathie (3/20) des ZNS wurden retrospektiv ausgewertet. Eingeschlossen wurden Patienten mit Laesionen des Hirnparenchymsgroessen 3 mm in den T{sub 2}-gewichteten Sequenzen der MRT, wobei diese Veraenderungen aufgrund umfangreicher klinischer Untersuchungen nicht auf das Vorliegen neurodegenerativer, anderweitig entzuendlicher, metastatischer oder embolischer Ursachen zurueckzufuehren waren. Fuer die MRA wurde eine TOF 3D FISP-Sequenz auf einem 1,5T MR-Geraet verwendet. Ergebnisse: MR-angiographisch wurden bei 15/20 Patienten (75

Generalised brain edema and brain infarct in ergotamine abuse: Visualization by CT, MR and angiography

International Nuclear Information System (INIS)

Toedt, C.; Hoetzinger, H.; Salbeck, R.; Beyer, H.K.

1989-01-01

Abuse of ergotamine can release a generalised brain edema and brain infarctions. This can be visualized by CT, MR and angiography. The reason, however, can only be found in the patients history. (orig.) [de

C-arm computed tomography for transarterial chemoperfusion and chemo-embolization of thoracic lesions; Transarterielle Chemoperfusion und -embolisation thorakaler Neoplasmen mittels C-Arm CT

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Vogl, T.J.; Naguib, N.N.; Nour-Eldin, N.E.; Lehnert, T.; Mbalisike, E. [Klinikum der Johann-Wolfgang-Goethe-Universitaet, Institut fuer Diagnostische und Interventionelle Radiologie, Frankfurt am Main (Germany)

2009-09-15

To evaluate the role of C-arm CT for on-line fluoroscopy in regional transarterial chemoperfusion (TACP) and chemo-embolization (TPCE) of primary and secondary malignant thoracic lesions. From September 2008 to March 2009 a total of 31 patients (20 males and 11 females, average age: 61.7 years, range 22-84 years) with 53 thoracic malignant lesions from different origins (primary or secondary pulmonary carcinoma n=37, pleural mesothelioma n=16) were treated with TACP or TPCE using flat-detector CT (FD-CT). C-arm CT of the latest generation was used to localize the lesion before local chemotherapy (Artis Zeego, Siemens, Erlangen). For TACP a 220 rotation and a volume of 150 ml (ratio of 1:2 contrast/normal saline), delay 2 s and flow 12 ml/s was used. For TPCE a volume of 75 ml (ratio of 1:2 contrast/normal saline), delay 2 s and flow 3 ml/s was used. TPCE C-arm CT allowed the evaluation of the degree of perfusion of the tumor and the geographic areas of enhancement correlated with the post-interventional lipiodol uptake in MSCT. In TACP the intercostal arteries involved could be visualized and in 30% of interventions the catheter had to be repositioned for the following intervention. C-arm CT provides additional information on the vascular characteristics and perfusion of pulmonary lesions resulting in a change of interventional strategy in a relevant number of patients. (orig.) [German] Ziel der Arbeit war die Evaluation der Wertigkeit der C-Arm CT fuer die online gesteuerte regionale transarterielle Chemoperfusion (TACP) und die transpulmonale Chemoembolisation (TPCE) primaerer und sekundaerer thorakaler Neoplasmen Von September 2008 bis Maerz 2009 wurden 31 Patienten (11 Frauen/20 Maenner, Durchschnittsalter 61,7 Jahre) mit 53 unterschiedlichen thorakalen Neoplasmen (primaere oder sekundaere Lungenkarzinome [n=37], Pleuramesotheliome [n=16]) mittels TACP oder TPCE unter Einsatz der Flachdetektortechnologie (FD-CT) behandelt. Alle Behandlungen erfolgten an einem C

Evaluation of patellar cartilage surface lesions: comparison of CT arthrography and fat-suppressed FLASH 3D MR imaging

International Nuclear Information System (INIS)

Daenen, B.R.; Ferrara, M.A.; Marcelis, S.; Dondelinger, R.F.

1998-01-01

The aim of this study was to evaluate the sensitivity and specificity of fat-suppressed fast low-angle shot (FLASH) 3D MR imaging in the detection of patellar cartilage surface lesions in comparison with CT arthrography. Fifty patients, with or without symptoms of chondromalacia, were prospectively examined by CT arthrography and fat-suppressed 3D gradient-echo MR imaging. All MR examinations were evaluated by three observers, two of them reaching a consensus interpretation. The lesions were graded according to their morphology and their extent. The CT arthrography was considered as the reference examination. For both sets of observers, the final diagnosis of chondromalacia was obtained in 92.5 %. The specificity was 60 % on a patient-by-patient basis. Fissures were missed in 83 and 60 %, respectively, but were isolated findings only in 2.5 % of the cases. Considering ulcers involving more than 50 % of the cartilage thickness, 65 and 88 %, respectively, were recognized. Fat-suppressed FLASH 3D is an adequate pulse sequence for the detection of patellar cartilage ulcers. It can be applied on a routine clinical basis, but it does not show as many fissures as CT arthrography and is less precise for grading of lesions. (orig.)

Evaluation of patellar cartilage surface lesions: comparison of CT arthrography and fat-suppressed FLASH 3D MR imaging

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Daenen, B.R.; Ferrara, M.A.; Marcelis, S.; Dondelinger, R.F. [Department of Medical Imaging, University Hospital Sart-Tilman, Liege (Belgium)

1998-07-01

The aim of this study was to evaluate the sensitivity and specificity of fat-suppressed fast low-angle shot (FLASH) 3D MR imaging in the detection of patellar cartilage surface lesions in comparison with CT arthrography. Fifty patients, with or without symptoms of chondromalacia, were prospectively examined by CT arthrography and fat-suppressed 3D gradient-echo MR imaging. All MR examinations were evaluated by three observers, two of them reaching a consensus interpretation. The lesions were graded according to their morphology and their extent. The CT arthrography was considered as the reference examination. For both sets of observers, the final diagnosis of chondromalacia was obtained in 92.5 %. The specificity was 60 % on a patient-by-patient basis. Fissures were missed in 83 and 60 %, respectively, but were isolated findings only in 2.5 % of the cases. Considering ulcers involving more than 50 % of the cartilage thickness, 65 and 88 %, respectively, were recognized. Fat-suppressed FLASH 3D is an adequate pulse sequence for the detection of patellar cartilage ulcers. It can be applied on a routine clinical basis, but it does not show as many fissures as CT arthrography and is less precise for grading of lesions. (orig.) With 4 figs., 3 tabs., 21 refs.

MR arthrography of the shoulder: possible indications for clinical use; Einsatzmoeglichkeiten der MR-Arthrographie bei Erkrankungen des Schultergelenkes

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Kreitner, K.F. [Mainz Univ. (Germany). Klinik mit Poliklinik fuer Radiologie; Grebe, P. [Mainz Univ. (Germany). Klinik mit Poliklinik fuer Radiologie; Kersjes, W. [Mainz Univ. (Germany). Klinik mit Poliklinik fuer Radiologie; Runkel, M. [Mainz Univ. (Germany). Klinik fuer Unfallchirurgie; Kirschner, P. [Elisabeth-Hospital, Mainz (Germany). Abt. fuer Unfall- und Wiederherstellungschirurgie St. Vincenz; Schild, H.H. [Mainz Univ. (Germany). Klinik mit Poliklinik fuer Radiologie

1994-02-01

In a prospective study possible indications for MR arthrography of the shoulder were evaluated. 37 patients were examined before and after intraarticular administration of a 2-mmolar solution of Gd-DTPA. MR arthrography was performed if there was no joint effusion and/or an uncertain finding concerning the rotator cuff or the capsulolabral complex on plain MR images. MR arthrography leads to a better demonstration of labrum pathology in 11/22 patients and to a superior delineation of the capsuloligamentous apparatus in 20/22 cases. In 9/15 patients with impingement lesions MR arthrography allowed a differentiation of severe tendinitis from partial and small full-thickness tears of the rotator cuff. MR arthrography of the shoulder joint enhances the accuracy of MR in case of an uncertain finding on plain MR images. (orig.) [Deutsch] In einer prospektiven Studie sollten Einsatzmoeglichkeiten der MR-Arthrographie bei Erkrankungen des Schultergelenkes herausgearbeitet werden. 37 Patienten wurden sowohl nativ als auch nach intraartikulaerer Gabe einer 2mmolaren Gd-DTPA-Loesung untersucht. Voraussetzungen fuer die KM-Gabe waren ein fehlender Gelenkerguss und/oder ein unklarer Befund des Labrum-Kapsel-Komplexes oder der Rotatorenmanschette in der Nativuntersuchung. Durch die MR-Arthrographie wurde bei 11/22 Patienten eine verbesserte Darstellung der Labrumpathologie erzielt; in 20/22 Faellen ergabe sich eine zuverlaessige Beurteilung der Gelenkkapsel. Bei 9/15 Patienten mit Erkrankungen der Rotatorenmanschette konnten Tendinitiden von partiellen und kleinen kompletten Rotatorenmanschettenrupturen sicher differenziert werden. Die MR-Arthrographie des Schultergelenkes fuehrt bei nicht eindeutigen Befunden in der Nativuntersuchung zu einer verbesserten Treffsicherheit der MR-Diagnostik. (orig.)

Diagnosis and differential diagnosis of hydrocephalus in adults; Diagnostik und Differenzialdiagnostik des Hydrozephalus beim Erwachsenen

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Langner, Soenke; Mensel, Birger; Kuehn, Jens Peter; Kirsch, Michael [Univ. Medicine Greifswald (Germany). Inst. for Diagnostic Radiology and Neuroradiology; Fleck, Steffen; Baldauf, Joerg [Univ. Medicine Greifswald (Germany). Dept. of Neurosurgery

2017-08-15

Hydrocephalus is caused by an imbalance of production and absorption of cerebrospinal fluid (CSF) or obstruction of its pathways, resulting in ventricular dilatation and increased intracranial pressure. Imaging plays a crucial role in the diagnosis, differential diagnosis and planning of treatment. This review article presents the different types of hydrocephalus und their typical imaging appearance, describes imaging techniques, and discusses differential diagnoses of the different forms of hydrocephalus. Imaging plays a central role in the diagnosis of hydrocephalus. While magnetic resonance (MR) imaging is the first-line imaging modality, computed tomography (CT) is often the first-line imaging test in emergency patients.

CT and MR in non-neonatal hypoxic-ischemic encephalopathy: radiological findings with pathophysiological correlations

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Gutierrez, Leonardo Guilhermino; Portela, Luiz Antonio Pezzi [Hospital Alemao Oswaldo Cruz and Hospital do Coracao, Diagnostic Imaging Division, Sao Paulo (Brazil); Rovira, Alex [University Hospital Vall d' Hebron, MR Unit, Department of Radiology, Barcelona (Spain); Costa Leite, Claudia da [Clinics Hospital of the University of Sao Paulo, School of Medicine, Department of Radiology, Sao Paulo (Brazil); Lucato, Leandro Tavares [Hospital Alemao Oswaldo Cruz and Hospital do Coracao, Diagnostic Imaging Division, Sao Paulo (Brazil); Clinics Hospital of the University of Sao Paulo, School of Medicine, Department of Radiology, Sao Paulo (Brazil)

2010-11-15

Non-neonatal hypoxic-ischemic encephalopathy is a clinical condition often related to cardiopulmonary arrest that demands critical management and treatment decisions. Management depends mainly on the degree of neurological impairment and prognostic considerations. Computed tomography (CT) is often used to exclude associated or mimicking pathology. If any, only nonspecific signs such as cerebral edema, sulci effacement, and decreased gray matter (GM)/white matter (WM) differentiation are evident. Pseudosubarachnoid hemorrhage, a GM/WM attenuation ratio <1.18, and inverted GM attenuation are associated with a poor prognosis. Magnetic resonance (MR) imaging is more sensitive than CT in assessing brain damage in hypoxic-ischemic encephalopathy. Some MR findings have similarities to those seen pathologically, based on spatial distribution and time scale, such as lesions distributed in watershed regions and selective injury to GM structures. In the acute phase, lesions are better depicted using diffusion-weighted imaging (DWI) because of the presence of cytotoxic edema, which, on T2-weighted images, only become apparent later in the early subacute phase. In the late subacute phase, postanoxic leukoencephalopathy and contrast enhancement could be observed. In the chronic phase, atrophic changes predominate over tissue signal changes. MR can be useful for estimating prognosis when other tests are inconclusive. Some findings, such as the extent of lesions on DWI and presence of a lactate peak and depleted N-acetyl aspartate peak on MR spectroscopy, seem to have prognostic value. (orig.)

CT and MR in non-neonatal hypoxic-ischemic encephalopathy: radiological findings with pathophysiological correlations

International Nuclear Information System (INIS)

Gutierrez, Leonardo Guilhermino; Portela, Luiz Antonio Pezzi; Rovira, Alex; Costa Leite, Claudia da; Lucato, Leandro Tavares

2010-01-01

Non-neonatal hypoxic-ischemic encephalopathy is a clinical condition often related to cardiopulmonary arrest that demands critical management and treatment decisions. Management depends mainly on the degree of neurological impairment and prognostic considerations. Computed tomography (CT) is often used to exclude associated or mimicking pathology. If any, only nonspecific signs such as cerebral edema, sulci effacement, and decreased gray matter (GM)/white matter (WM) differentiation are evident. Pseudosubarachnoid hemorrhage, a GM/WM attenuation ratio <1.18, and inverted GM attenuation are associated with a poor prognosis. Magnetic resonance (MR) imaging is more sensitive than CT in assessing brain damage in hypoxic-ischemic encephalopathy. Some MR findings have similarities to those seen pathologically, based on spatial distribution and time scale, such as lesions distributed in watershed regions and selective injury to GM structures. In the acute phase, lesions are better depicted using diffusion-weighted imaging (DWI) because of the presence of cytotoxic edema, which, on T2-weighted images, only become apparent later in the early subacute phase. In the late subacute phase, postanoxic leukoencephalopathy and contrast enhancement could be observed. In the chronic phase, atrophic changes predominate over tissue signal changes. MR can be useful for estimating prognosis when other tests are inconclusive. Some findings, such as the extent of lesions on DWI and presence of a lactate peak and depleted N-acetyl aspartate peak on MR spectroscopy, seem to have prognostic value. (orig.)

CT and MR imaging findings of xanthogranulomatous cholecystitis: correlation with pathologic findings

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Shuto, R.; Kiyosue, H.; Komatsu, E.; Matsumoto, S.; Mori, H. [Oita Medical Univ. (Japan). Dept. of Radiology; Kawano, K. [Oita Medical Univ. (Japan). Dept. of First Surgery; Kondo, Y.; Yokoyama, S. [Oita Medical Univ. (Japan). Dept. of First Pathology

2004-03-01

The aim of this study was to evaluate CT and MRI findings in xanthogranulomatous cholecystitis (XGC) and to correlate the imaging findings with various pathologic parameters. The study included 13 patients with histopathologically confirmed XGC. The CT (n=13) and MRI (n=5) obtained in these patients were evaluated retrospectively. On CT, low-attenuation areas in the wall of XGC correlated with foam and inflammatory cells or necrosis and/or abscess in XGC. Areas of iso- to slightly high signal intensity on T2-weighted images, showing slight enhancement at early phase and strong enhancement at last phase on dynamic study, corresponded with areas of abundant xanthogranulomas. Areas with very high signal intensity on T2-weighted images without enhancement corresponded with necrosis and/or abscesses. Luminal surface enhancement (LSE) of gallbladder wall represented preservation of the epithelial layer. The early-enhanced areas of the liver bed on dynamic CT and MR images corresponded with accumulation of inflammatory cells and abundant fibrosis. Our results indicate that CT and MRI findings correlate well with the histopathologic findings of XGC.

MR, CT, and myelographic features of epidural lipomatosis

International Nuclear Information System (INIS)

Quint, D.J.; Boulos, R.S.; Patel, S.C.; Sanders, W.P.; Tiel, R.L.; Washington, J.M.

1987-01-01

Central deposition of fat is a well-known clinical feature of chronically elevated corticosteroid levels. Rarely described is increased extradural fat causing compression of the spinal cord and neurologic deficits. Twelve previously reported and five new cases of epidural lipomatosis are presented. Representative examples of the common myelographic and CT findings in this disorder are shown. In addition, previously undescribed examples of epidural lipomatosis demonstrating (1) the MR findings, (2) no associated myelographic block, (3) lipomatosis in both the thoracic and lumbar regions, and (4) a case in a nonobese patient without known steroid use are presented. The importance of considering this entity in the appropriate clinical setting (chronic exogenous steroid use) even with a normal myelogram is stressed

Shoulder instability syndrome: comparison of CT, arthrography and MR findings

International Nuclear Information System (INIS)

Ortiz, L.; Alcaraz, M.; Preciados, J.L.G.; Garcia Alvarez, A.; Castello, J.

1995-01-01

Currently, the two most reliable explorations for diagnosing the lesions that produce shoulder instability are computerized tomography with arthrography and magnetic resonance following intraarticular injection of gadolinium. Dynamic CT arthrography is considered the best method to assess these lesions; MR is a similar procedure but involves certain drawbacks, among them, its cost. The techniques applied in these explorations are reviewed, as are the anatomy of the different components of this joint and the radiological findings leading to a diagnosis of the pathology underlying its instability. (Author)

Initial Experience of Using Dual-Energy CT with an Iodine Overlay Image for Hand Psoriatic Arthritis: Comparison Study with Contrast-enhanced MR Imaging.

Science.gov (United States)

Fukuda, Takeshi; Umezawa, Yoshinori; Tojo, Shinjiro; Yonenaga, Takenori; Asahina, Akihiko; Nakagawa, Hidemi; Fukuda, Kunihiko

2017-07-01

Purpose To determine the feasibility of dual-energy (DE) computed tomography (CT) with an iodine overlay image (IOI) for evaluation of psoriatic arthritis in the hand. Materials and Methods Approval from the institutional ethics committee and written informed consent from all patients were obtained. This prospective study included 16 patients who had psoriasis with finger joint symptoms from January 2015 to January 2016. Contrast material-enhanced (CE) DE CT and 1.5-T CE magnetic resonance (MR) imaging were performed within 1 month of each other. DE CT was performed with a tube voltage of 80 kV and 140 kV with use of a 0.4-mm tin filter. Images acquired with both modalities were evaluated by two radiologists independently by using a semiquantitative scoring system. Interreader agreement was calculated for each modality: Weighted κ values were calculated for synovitis, flexor tenosynovitis, and extensor peritendonitis, and κ values were calculated for periarticular inflammation. With consensus scores and CE MR images as the reference, the sensitivity and specificity of IOI DE CT for inflammatory lesions were calculated. Statistical analysis of discordant readings was performed by using the McNemar test. Results Interreader agreement for inflammatory lesions was excellent or good (weighted κ = 0.83 and κ = 0.75 in IOI DE CT; weighted κ = 0.81 and κ = 0.87 in CE MR imaging). The sensitivity and specificity of IOI DE CT were 0.78 and 0.87, respectively. Total agreement was 86.3%; however, there were significantly more lesions detected with IOI DE CT than with CE MR imaging alone (134 vs 20 lesions in 1120 evaluated items; P the abnormalities detected with IOI DE CT alone were located in distal interphalangeal joints. Conclusion IOI DE CT is a new imaging modality that may be useful for evaluating psoriatic arthritis in the hand, particularly in the detection of inflammatory lesions in small joints, and may be more useful than CE MR imaging, within the limitation

CT versus MR Techniques in the Detection of Cervical Artery Dissection.

Science.gov (United States)

Hanning, Uta; Sporns, Peter B; Schmiedel, Meilin; Ringelstein, Erich B; Heindel, Walter; Wiendl, Heinz; Niederstadt, Thomas; Dittrich, Ralf

2017-11-01

Spontaneous cervical artery dissection (sCAD) is an important etiology of juvenile stroke. The gold standard for the diagnosis of sCAD is convential angiography. However, magnetic resonance imaging (MRI)/MR angiography (MRA) and computed tomography (CT)/CT angiography (CTA) are frequently used alternatives. New developments such as multislice CT/CTA have enabled routine acquisition of thinner sections with rapid imaging times. The goal of this study was to compare the capability of recent developed 128-slice CT/CTA to MRI/MRA to detect radiologic features of sCAD. Retrospective review of patients with suspected sCAD (n = 188) in a database of our Stroke center (2008-2014), who underwent CT/CTA and MRI/MRA on initial clinical work-up. A control group of 26 patients was added. All Images were evaluated concerning specific and sensitive radiological features for dissection by two experienced neuroradiologists. Imaging features were compared between the two modalities. Forty patients with 43 dissected arteries received both modalities (29 internal carotid arteries [ICAs] and 14 vertebral arteries [VAs]). All CADs were identified in CT/CTA and MRI/MRA. The features intimal flap, stenosis, and lumen irregularity appeared in both modalities. One high-grade stenosis was identified by CT/CTA that was expected occluded on MRI/MRA. Two MRI/MRA-confirmed pseudoaneurysms were missed by CT/CTA. None of the controls evidenced specific imaging signs for dissection. CT/CTA is a reliable and better available alternative to MRI/MRA for diagnosis of sCAD. CT/CTA should be used to complement MRI/MRA in cases where MRI/MRA suggests occlusion. Copyright © 2017 by the American Society of Neuroimaging.

Profiles of intensity loads in physical education classes in Poland Profily intenzivní zátěže v hodinách tělesné výchovy v Polsku

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Michał Bronikowski

2006-02-01

Full Text Available The aim of the research was to compare the health-related effectiveness of various types of physical education lessons on the cardio-respiratory system. The research was carried out in the years 2002 and 2003 in two junior high schools in Poznań. There were four types of classes examined: outdoor athletics, volleyball, basketball and fun games, each type lasting 45 minutes. Heart rates of two randomly selected pupils aged 15–16 were recorded during class, with the use of Polar heart rate monitors. According to the findings of a cross-national study, Polish youth do not have enough moderate-to-vigorous activity on a daily basis (Cabak & Woynarowska, 2004. In our research the most effective in stimulating cardio-respiratory fitness appeared to be outdoor athletics classes in boys and girls, and basketball in boys. Our data support the earlier findings of other studies (Stratton, 1997; Fairclough & Stratton, 2005. Cílem průzkumu bylo srovnání zdravotní účinnosti různých typů hodin tělesné výchovy na kardio-respirační ústrojí. Průzkum byl prováděn v letech 2002 a 2003 na nižším stupni středních škol v Poznani. Zkoumány byly čtyři typy hodin: atletika, volejbal, basketbal a pohybové hry, přičemž každý typ měl trvání 45 minut. V průběhu hodiny byla u dvou náhodně zvolených 15–16letých žáků měřena srdeční frekvence, a to pomocí monitorů srdeční frekvence Polar. Podle výsledků celonárodního výzkumu nemá polská mládež dostatek každodenní střední až intenzivní aktivity (Cabak & Woynarowska, 2004. V našem průzkumu se hodiny atletiky, v případě chlapců a dívek, a basketbalu, v případě chlapců, jevily jako hodiny nejúčinněji stimulující kardio-respirační zdatnost. Naše údaje potvrzují dřívější výsledky jiných průzkumů (Stratton, 1997; Fairclough & Stratton, 2005.

Experimental MR-guided cryotherapy of the brain with almost real-time imaging by radial k-space scanning; Experimentelle MR-gesteuerte Kryotherapie des Gehirns mit nahezu Echtzeitdarstellung durch radiale k-Raum-Abtastung

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Tacke, J.; Schorn, R.; Glowinski, A.; Grosskortenhaus, S.; Adam, G.; Guenther, R.W. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Speetzen, R.; Rau, G. [Helmholtz-Institut fuer Biomedizinische Technik, Aachen (Germany); Rasche, V. [Philips GmbH Forschungslaboratorium, Hamburg (Germany)

1999-02-01

Purpose: To test radial k-space scanning by MR fluoroscopy to guide and control MR-guided interstitial cryotherapy of the healthy pig brain. Methods: After MR tomographic planning of the approach, an MR-compatible experimental cryotherapy probe of 2.7 mm diameter was introduced through a 5 mm burr hole into the right frontal brain of five healthy pigs. The freeze-thaw cycles were imaged using a T{sub 1}-weighted gradient echo sequence with radial k-space scanning in coronal, sagittal, and axial directions. Results: The high temporal resolution of the chosen sequence permits a continuous representation of the freezing process with good image quality and high contrast between ice and unfrozen brain parenchyma. Because of the interactive conception of the sequence the layer plane could be chosen as desired during the measurement. Ice formation was sharply demarcated, spherically configurated, and was free of signals. Its maximum diameter was 13 mm. Conclusions: With use of the novel, interactively controllable gradient echo sequence with radial k-space scanning, guidance of the intervention under fluoroscopic conditions with the advantages of MRT is possible. MR-guided cryotherapy allows a minimally-invasive, precisely dosable focal tissue ablation. (orig.) [Deutsch] Ziel: Erprobung der radialen k-Raum-Abtastung bei der MR-Fluoroskopie zur Steuerung und Kontrolle MR-gesteuerter interstitieller Kryotherapie des gesunden Schweinegehirns. Methoden: Nach MR-tomographischer Planung des Zugangsweges wurde eine MR-kompatible experimentelle Kryotherapiesonde von 2,7 mm Durchmesser ueber ein 5 mm Bohrloch in das rechte Frontalhirn von fuenf gesunden Schweinen eingebracht. Die Frier-/Tauzyklen wurden anhand einer T{sub 1}-gewichteten Gradientenechosequenz mit radialer k-Raum-Abtastung in koronarer, sagittaler und axialer Schichtfuehrung dargestellt. Ergebnisse: Die hohe zeitliche Aufloesung der gewaehlten Sequenz erlaubte eine kontinuierliche Darstellung des Friervorgangs bei

Image analysis of the inner ear with CT and MR imaging

International Nuclear Information System (INIS)

Kumakawa, Kohzoh; Takeda, Hidehiko; Mutoh, Naoko; Miyakawa, Kohichi; Yukawa, Kumiko; Funasaka, Sohtaro.

1992-01-01

Recent progress in magnetic resonance imaging (MRI) has made it possible to obtain detailed images of the inner ear by delineating the lymphatic fluid within the labyrinth. We analyzed CT scans and MR imaging in 70 ears manifesting profound deafness owing to inner ear lesions and compared their detective ability for inner ear lesions. The following results were obtained. CT scan examination showed slight to extensive ossification of the labyrinth in six ears (9%), whereas MRI examination revealed low to absent signal intensity of the inner ear in nine ears (13%). Therefore, it was concluded that MRI is more sensitive in detecting abnormalities of the inner ear than CT scan. MRI provided useful information as to whether the cochlear turn is filled with lymphatic fluid or obstructed. This point was one of the greatest advantages of MRI over CT scan. Abnormal findings in either or both the CT scan and the MRI were detected in suppurative labyrinthitis occurring secondary to chronic otitis media, bacterial meningitis and in inner ear trauma. However, such abnormal findings were not detected in patients with idiopathic progressive sensorineural hearing loss, ototoxity or sudden deafness. These findings should be taken into consideration in pre-operative assessment of cochlear implant candidates. (author)

Direct spondylolisthesis identification and measurement in MR/CT using detectors trained by articulated parameterized spine model

Science.gov (United States)

Cai, Yunliang; Leung, Stephanie; Warrington, James; Pandey, Sachin; Shmuilovich, Olga; Li, Shuo

2017-02-01

The identification of spondylolysis and spondylolisthesis is important in spinal diagnosis, rehabilitation, and surgery planning. Accurate and automatic detection of spinal portion with spondylolisthesis problem will significantly reduce the manual work of physician and provide a more robust evaluation for the spine condition. Most existing automatic identification methods adopted the indirect approach which used vertebrae locations to measure the spondylolisthesis. However, these methods relied heavily on automatic vertebra detection which often suffered from the pool spatial accuracy and the lack of validated pathological training samples. In this study, we present a novel spondylolisthesis detection method which can directly locate the irregular spine portion and output the corresponding grading. The detection is done by a set of learning-based detectors which are discriminatively trained by synthesized spondylolisthesis image samples. To provide sufficient pathological training samples, we used a parameterized spine model to synthesize different types of spondylolysis images from real MR/CT scans. The parameterized model can automatically locate the vertebrae in spine images and estimate their pose orientations, and can inversely alter the vertebrae locations and poses by changing the corresponding parameters. Various training samples can then be generated from only a few spine MR/CT images. The preliminary results suggest great potential for the fast and efficient spondylolisthesis identification and measurement in both MR and CT spine images.

MR-CT registration using a Ni-Ti prostate stent in image-guided radiotherapy of prostate cancer

International Nuclear Information System (INIS)

Korsager, Anne Sofie; Østergaard, Lasse Riis; Carl, Jesper

2013-01-01

Purpose: In image-guided radiotherapy of prostate cancer defining the clinical target volume often relies on magnetic resonance (MR). The task of transferring the clinical target volume from MR to standard planning computed tomography (CT) is not trivial due to prostate mobility. In this paper, an automatic local registration approach is proposed based on a newly developed removable Ni-Ti prostate stent.Methods: The registration uses the voxel similarity measure mutual information in a two-step approach where the pelvic bones are used to establish an initial registration for the local registration.Results: In a phantom study, the accuracy was measured to 0.97 mm and visual inspection showed accurate registration of all 30 data sets. The consistency of the registration was examined where translation and rotation displacements yield a rotation error of 0.41° ± 0.45° and a translation error of 1.67 ± 2.24 mm.Conclusions: This study demonstrated the feasibility for an automatic local MR-CT registration using the prostate stent.

MR-CT registration using a Ni-Ti prostate stent in image-guided radiotherapy of prostate cancer

Energy Technology Data Exchange (ETDEWEB)

Korsager, Anne Sofie; Ostergaard, Lasse Riis [Department of Health Science and Technology, Aalborg University, Aalborg 9220 (Denmark); Carl, Jesper [Department of Medical Physics, Oncology, Aalborg Hospital, Aalborg 9100 (Denmark)

2013-06-15

Purpose: In image-guided radiotherapy of prostate cancer defining the clinical target volume often relies on magnetic resonance (MR). The task of transferring the clinical target volume from MR to standard planning computed tomography (CT) is not trivial due to prostate mobility. In this paper, an automatic local registration approach is proposed based on a newly developed removable Ni-Ti prostate stent.Methods: The registration uses the voxel similarity measure mutual information in a two-step approach where the pelvic bones are used to establish an initial registration for the local registration.Results: In a phantom study, the accuracy was measured to 0.97 mm and visual inspection showed accurate registration of all 30 data sets. The consistency of the registration was examined where translation and rotation displacements yield a rotation error of 0.41 Degree-Sign {+-} 0.45 Degree-Sign and a translation error of 1.67 {+-} 2.24 mm.Conclusions: This study demonstrated the feasibility for an automatic local MR-CT registration using the prostate stent.

MR evaluation of CSF fistulae

International Nuclear Information System (INIS)

Gupta, V.; Goyal, M.; Mishra, N.; Gaikwad, S.; Sharma, A.

1997-01-01

Purpose: To evaluate the role of MR imaging in the localisation of cerebrospinal fluid (CSF) fistulae. Material and Methods: A total of 36 consecutive unselected patients with either clincally proven CSF leakage (n=26) or suspected CSF fistula (n=10) were prospectively evaluated by MR. All MR examinations included fast spin-echo T2-weighted images in the 3 orthogonal planes. Thin-section CT was performed following equivocal or negative MR examination. MR and CT findings were correlated with surgical results in 33 patients. Results: CSF fistula was visualised as a dural-bone defect with hyperintense fluid signal continuous with that in the basal cisterns on T2-weighted images. MR was positive in 26 cases, in 24 of which the fistula was confirmed surgically. In 2 patients the CSF leakage was directly demonstrated on MR. MR sensitivity of 80% compared favourably with the reported 46-81% of CT cisternography (CTC). No significant difference in MR sensitivity in detecting CSF fistula was found between active and inactive leaks. (orig.)

Functional CT imaging: load-dependent visualization of the subchondral mineralization by means of CT osteoabsorptionmetry (CT-OAM); Funktionelle Computertomographie: Beanspruchungsabhaengige Darstellung der subchondralen Mineralisierung mittels CT gestuetzter Osteoabsorptiometrie (CTOAM)

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Linsenmaier, U.; Schlichtenhorst, K.; Pfeifer, K.J.; Reiser, M. [Inst. fuer Klinische Radiologie, Innenstadt, Ludwig-Maximilians-Univ. Muenchen (Germany); Kersting, S.; Putz, R.; Mueller-Gerbl, M. [Anatomische Anstalt, Ludwig-Maximilians-Univ. Muenchen (Germany)

2003-05-01

Purpose: Functional computed tomography for visualization and quantification of subchondral bone mineralization using CT osteoabsorptiometry (CT-OAM). Materials and Methods: Tarsometatarsal (TMT) and metatarsophalangeal (MTP) joints of 46 human hallux valgus (HV) specimens were examined (sagittal 1/1/1 mm) on a single slice CT scanner SCT (Somatom Plus 4, Siemens AG). Subchondral bone pixels were segmented and assigned to 10 density value groups (triangle 100 HU, range 200 - 1200 HU) the pixels using volume rendering technique (VRT). The data analysis considered the severity of HV as determined by the radiographically measured HV-angle (a.p. projection). Results: CT-OAM could generate reproducible densitograms of the distribution pattern of the subchondral bone density for all four joint surfaces (TMT and MTP joints). The bone density localization enables the assignment to different groups, showing a characteristic HV-angle-dependent distribution of the maximum bone mineralization of the load-dependent densitogram (p < 0.001). Conclusion: CT-OAM is a functional CT technique for visualizing and quantifying the distribution of the subchondral bone density, enabling a noninvasive load-dependent assessment of the joint surfaces. Load-dependent densitograms of hallux valgus specimens show a characteristic correlation with an increase of the HV-angle. (orig.) [German] Ziel: Darstellung und Quantifizierung der subchondralen Mineralisierung in Abhaengigkeit von unterschiedlichen Beanspruchungssituationen mittels funktioneller Computertomographie als CT-Osteoabsorptiometrie (CT-OAM). Methode: An 46 humanen Praeparaten mit Hallux valgus (HV) wurden exemplarisch die TMT I (Tarsometatarsal)- und MTP I (Metatarsophalangeal)-Gelenke des ersten Strahles (sagittal 1/1/1 mm) an einem Singleslice Spiral-CT (SCT, Somatom Plus 4, Siemens AG) untersucht. Der subchondrale Knochen wurde segmentiert, den Pixel wurde mittels Volume Rendering Technik (VRT) 10 Graustufenbereiche (D100 HU

Clinical evaluation of PET image quality as a function of acquisition time in a new TOF-PET/MR compared to TOF-PET/CT - initial results

International Nuclear Information System (INIS)

Zeimpekis, Konstantinos; Huellner, Martin; De Galiza Barbosa, Felipe; Ter Voert, Edwin; Davison, Helen; Delso, Gaspar; Veit-Haibach, Patrick

2015-01-01

The recently available integrated PET/MR imaging can offer significant additional advances in clinical imaging. The purpose of this study was to compare the PET performance between a PET/CT scanner and an integrated TOF-PET/MR scanner concerning image quality parameters and quantification in terms of SUV as a function of acquisition time (a surrogate of dose). Five brain and five whole body patients were included in the study. The PET/CT scan was used as a reference and the PET/MR acquisition time was consecutively adjusted, taking into account the decay between the scans in order to expose both systems to the same amount of emitted signal. The acquisition times were then retrospectively reduced to assess the performance of the PET/MRI for lower count rates. Image quality, image sharpness, artifacts and noise were evaluated. SUV measurements were taken in the liver and in white matter to compare quantification. Quantitative evaluation showed good correlation between PET/CT and PET/MR brain SUVs. Liver correlation was lower, with uptake underestimation in PET/MR, partially justified by bio-redistribution. The clinical evaluation showed that PET/MR offers higher image quality and sharpness with lower levels of noise and artefacts compared to PET/CT with reduced acquisition times for whole body scans, while for brain scans there is no significant difference. The PET-component of the TOF-PET/MR showed higher image quality compared to PET/CT as tested with reduced imaging times. However, these results account mainly for body imaging, while no significant difference were found in brain imaging. This overall higher image quality suggests that the acquisition time or injected activity can be reduced by at least 37% on the PET/MR scanner.

Clinical evaluation of PET image quality as a function of acquisition time in a new TOF-PET/MR compared to TOF-PET/CT - initial results

Energy Technology Data Exchange (ETDEWEB)

Zeimpekis, Konstantinos; Huellner, Martin; De Galiza Barbosa, Felipe; Ter Voert, Edwin; Davison, Helen; Delso, Gaspar; Veit-Haibach, Patrick [Nuclear Medicine, University Hospital Zurich (Switzerland)

2015-05-18

The recently available integrated PET/MR imaging can offer significant additional advances in clinical imaging. The purpose of this study was to compare the PET performance between a PET/CT scanner and an integrated TOF-PET/MR scanner concerning image quality parameters and quantification in terms of SUV as a function of acquisition time (a surrogate of dose). Five brain and five whole body patients were included in the study. The PET/CT scan was used as a reference and the PET/MR acquisition time was consecutively adjusted, taking into account the decay between the scans in order to expose both systems to the same amount of emitted signal. The acquisition times were then retrospectively reduced to assess the performance of the PET/MRI for lower count rates. Image quality, image sharpness, artifacts and noise were evaluated. SUV measurements were taken in the liver and in white matter to compare quantification. Quantitative evaluation showed good correlation between PET/CT and PET/MR brain SUVs. Liver correlation was lower, with uptake underestimation in PET/MR, partially justified by bio-redistribution. The clinical evaluation showed that PET/MR offers higher image quality and sharpness with lower levels of noise and artefacts compared to PET/CT with reduced acquisition times for whole body scans, while for brain scans there is no significant difference. The PET-component of the TOF-PET/MR showed higher image quality compared to PET/CT as tested with reduced imaging times. However, these results account mainly for body imaging, while no significant difference were found in brain imaging. This overall higher image quality suggests that the acquisition time or injected activity can be reduced by at least 37% on the PET/MR scanner.

Clinical evaluation of the JPEG2000 compression rate of CT and MR images for long term archiving in PACS

International Nuclear Information System (INIS)

Cha, Soon Joo; Kim, Sung Hwan; Kim, Yong Hoon

2006-01-01

We wanted to evaluate an acceptable compression rate of JPEG2000 for long term archiving of CT and MR images in PACS. Nine CT images and 9 MR images that had small or minimal lesions were randomly selected from the PACS at our institute. All the images are compressed with rates of 5:1, 10:1, 20:1, 40:1 and 80:1 by the JPEG2000 compression protocol. Pairs of original and compressed images were compared by 9 radiologists who were working independently. We designed a JPEG2000 viewing program for comparing two images on one monitor system for performing easy and quick evaluation. All the observers performed the comparison study twice on 5 mega pixel grey scale LCD monitors and 2 mega pixel color LCD monitors, respectively. The PSNR (Peak Signal to Noise Ratio) values were calculated for making quantitative comparisions. On MR and CT, all the images with 5:1 compression images showed no difference from the original images by all 9 observers and only one observer could detect a image difference on one CT image for 10:1 compression on only the 5 mega pixel monitor. For the 20:1 compression rate, clinically significant image deterioration was found in 50% of the images on the 5M pixel monitor study, and in 30% of the images on the 2M pixel monitor. PSNR values larger than 44 dB were calculated for all the compressed images. The clinically acceptable image compression rate for long term archiving by the JPEG2000 compression protocol is 10:1 for MR and CT, and if this is applied to PACS, it would reduce the cost and responsibility of the system

Imaging of sacroiliitis in early seronegative spondylarthropathy. Assessment of abnormalities by MR in comparison with radiography and CT

DEFF Research Database (Denmark)

Puhakka, K Bøcker; Jurik, A G; Egund, N

2003-01-01

. MATERIAL AND METHODS: The SIJs of 41 patients with early SpA (median duration of inflammatory low back pain of 19 months) were evaluated by MR imaging using STIR, T1, T2, and T1 fat saturated (FS) sequences before and after i.v. Gd contrast medium followed by staging of abnormalities. The findings were...... compared with those obtained by CT and radiography. RESULTS: MR and CT had equal efficacy superior to radiography in staging of erosions and osseous sclerosis. Only MR allowed visualization and grading of active inflammatory changes in the subchondral bone and surrounding ligaments in addition to bone......: semicoronal T1 and both semicoronal and semiaxial STIR. If these images are normal, the examination can be finished; otherwise additional semicoronal T1 FS before and after i.v. contrast has to be performed as well as semiaxial post-contrast T1 FS....

Capability of differentiating smokers with normal pulmonary function from COPD patients: a comparison of CT pulmonary volume analysis and MR perfusion imaging

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Fan, Li; Xia, Yi; Guan, Yu; Yu, Hong; Liu, Shi-yuan [Changzheng Hospital of the Second Military Medical University, Department of Radiology, Shanghai (China); Zhang, Tie-feng; Li, Bing [Changzheng Hospital of the Second Military Medical University, Department of Respiration Medicine, Shanghai (China)

2013-05-15

To compare CT volume analysis with MR perfusion imaging in differentiating smokers with normal pulmonary function (controls) from COPD patients. Sixty-two COPD patients and 17 controls were included. The total lung volume (TLV), total emphysema volume (TEV) and emphysema index (EI) were quantified by CT. MR perfusion evaluated positive enhancement integral (PEI), maximum slope of increase (MSI), maximum slope of decrease (MSD), signal enhancement ratio (SER) and signal intensity ratio (R{sub SI}) of perfusion defects to normal lung. There were 19 class I, 17 class II, 14 class III and 12 class IV COPD patients. No differences were observed in TLV, TEV and EI between control and class I COPD. The control was different from class II, III and IV COPD in TEV and EI. The control was different from each class of COPD in R{sub SI,} MSI, PEI and MSD. Differences were found in R{sub SI} between class I and III, I and IV, and II and IV COPD. Amongst controls, MR detected perfusion defects more frequently than CT detected emphysema. Compared with CT, MR perfusion imaging shows higher potential to distinguish controls from mild COPD and appears more sensitive in identifying abnormalities amongst smokers with normal pulmonary function (controls). (orig.)

Capability of differentiating smokers with normal pulmonary function from COPD patients: a comparison of CT pulmonary volume analysis and MR perfusion imaging

International Nuclear Information System (INIS)

Fan, Li; Xia, Yi; Guan, Yu; Yu, Hong; Liu, Shi-yuan; Zhang, Tie-feng; Li, Bing

2013-01-01

To compare CT volume analysis with MR perfusion imaging in differentiating smokers with normal pulmonary function (controls) from COPD patients. Sixty-two COPD patients and 17 controls were included. The total lung volume (TLV), total emphysema volume (TEV) and emphysema index (EI) were quantified by CT. MR perfusion evaluated positive enhancement integral (PEI), maximum slope of increase (MSI), maximum slope of decrease (MSD), signal enhancement ratio (SER) and signal intensity ratio (R SI ) of perfusion defects to normal lung. There were 19 class I, 17 class II, 14 class III and 12 class IV COPD patients. No differences were observed in TLV, TEV and EI between control and class I COPD. The control was different from class II, III and IV COPD in TEV and EI. The control was different from each class of COPD in R SI, MSI, PEI and MSD. Differences were found in R SI between class I and III, I and IV, and II and IV COPD. Amongst controls, MR detected perfusion defects more frequently than CT detected emphysema. Compared with CT, MR perfusion imaging shows higher potential to distinguish controls from mild COPD and appears more sensitive in identifying abnormalities amongst smokers with normal pulmonary function (controls). (orig.)

Recognize and classify pneumoconiosis; Pneumokoniosen erkennen und klassifizieren

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Hering, K.G.; Hofmann-Preiss, K. [Klinikum Westfalen, Knappschaftskrankenhaus, Dortmund (Germany)

2014-12-15

In the year 2012, out of the 10 most frequently recognized occupational diseases 6 were forms of pneumoconiosis. With respect to healthcare and economic aspects, silicosis and asbestos-associated diseases are of foremost importance. The latter are to be found everywhere and are not restricted to large industrial areas. Radiology has a central role in the diagnosis and evaluation of occupational lung disorders. In cases of known exposure mainly to asbestos and quartz, the diagnosis of pneumoconiosis, with few exceptions will be established primarily by the radiological findings. As these disorders are asymptomatic for a long time they are quite often detected as incidental findings in examinations for other reasons. Therefore, radiologists have to be familiar with the pattern of findings of the most frequent forms of pneumoconiosis and the differential diagnoses. For reasons of equal treatment of the insured a quality-based, standardized performance, documentation and evaluation of radiological examinations is required in preventive procedures and evaluations. Above all, a standardized low-dose protocol has to be used in computed tomography (CT) examinations, although individualized concerning the dose, in order to keep radiation exposure as low as possible for the patient. The International Labour Office (ILO) classification for the coding of chest X-rays and the international classification of occupational and environmental respiratory diseases (ICOERD) classification used since 2004 for CT examinations meet the requirements of the insured and the occupational insurance associations as a means of reproducible and comparable data for decision-making. (orig.) [German] Im Jahr 2012 waren 6 der 10 am haeufigsten anerkannten Berufskrankheiten Pneumokoniosen. Gesundheitspolitisch und oekonomisch stehen dabei die Silikose und asbestassoziierte Erkrankungen im Vordergrund. Insbesondere Letztere treten ubiquitaer auf und sind nicht an grosse Industriestandorte gebunden