Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... of which shows a thin slice of the body. The images can then be studied from different angles by ... information please consult the ACR Manual on Contrast Media and its references. top of page What are the limitations of MRI of the Head? High-quality images are assured only if you are able to ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. MRI ...

Magnetic resonance imaging guided reirradiation of recurrent and second primary head and neck cancer

OpenAIRE

Chen, Allen M.; Cao, Minsong; Hsu, Sophia; Lamb, James; Mikaeilian, Argin; Yang, Yingli; Agazaryan, Nzhde; Low, Daniel A.; Steinberg, Michael L.

2017-01-01

Purpose: To report a single-institutional experience using magnetic resonance imaging (MRI) guided radiation therapy for the reirradiation of recurrent and second cancers of the head and neck. Methods and materials: Between October 2014 and August 2016, 13 consecutive patients with recurrent or new primary cancers of the head and neck that occurred in a previously irradiated field were prospectively enrolled in an institutional registry trial to investigate the feasibility and efficacy of ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... and may add approximately 15 minutes to the total exam time. top of page What will I ... the limitations of MRI of the Head? High-quality images are assured only if you are able ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... it may cause some medical devices to malfunction. Most orthopedic implants pose no risk, but you should ... a digital cloud server. Currently, MRI is the most sensitive imaging test of the head (particularly the ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played ... the limitations of MRI of the Head? High-quality images are assured only if you are able ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... for immediate assistance. Manufacturers of intravenous contrast indicate mothers should not breastfeed their babies for 24-48 ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... a computer to produce detailed pictures of the brain and other cranial structures that are clearer and ... sensitive imaging test of the head (particularly the brain) in routine clinical practice. top of page What ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... gadolinium contrast, it may still be possible to use it after appropriate pre-medication. Patient consent will ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... top of page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for ... Imaging (MRI) - Head Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... very early stage by mapping the motion of water molecules in the tissue. This water motion, known as diffusion, is impaired by most ... the limitations of MRI of the Head? High-quality images are assured only if you are able ...

Magnetic resonance imaging of avascular necrosis of the femoral head

Energy Technology Data Exchange (ETDEWEB)

Ozono, Kenji; Takaoka, Kunio [Osaka Univ. (Japan). Faculty of Medicine

1989-07-01

To evaluate the diagnostic value and limitation of magnetic resonance imaging (MRI) in avascular necrosis of the femoral head (ANF), clinical stages and types were examined on MRI scans of 68 femoral heads of 46 ANF patients. Stage 1 patients fell into two groups: (1) stage 1-A group of real ANF in which abnormal findings were observed on both MRI and bone scanning and (2) stage 1-B group of asymptomatic ANF in which MRI detected abnormality that was missed by bone scanning. In these groups, MRI showed inhomogeneous, band, and spotty patterns. Stage 2 or 3 patients tended to have homogeneous or ring-pattern hypointensities on MRI. Histological examination showed that repair reaction at the marginal site of hypointensity was partly responsible for the occurrence of hypointensities. In Stage 4 patients, not only femoral head but also acetabular site was visible as homogeneous hypointensity, which was similar to that in osteoarthritis. Because repair areas, as well as necrotic areas, were frequently visualized as hypointensities in Stages 2 or more, MRI might overestimate necrotic areas. (N.K.).

Magnetic resonance imaging of congenital dislocation of the hip with avascular necrosis of the femoral head

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Nobuhiko; Ikeda, Takeshi; Wada, Ikuo [Nagoya City Univ. (Japan). Faculty of Medicine; and others

1991-04-01

Magnetic resonance imaging (MRI) was performed on 22 patients (24 joints) with congenital dislocation of the hip (CDH) with avascular necrosis. T1 and T2 weighted images were obtained using spin echo techniques. Since positive images of the articular cartilage were obtained, it was possible to clearly image flattening or thickening of the articular cartilage of the femoral head and acetabulum in the coronal and in the axial plane of the T1 weighted image. There was a high intensity region in the femoral head with avascular necrosis in the coronal T2 weighted image. The wideness of the region increased with severity. Much information can be obtained with MRI and it is a useful technique in evaluating the pathology of CDH with avascular necrosis. (author).

Magnetic resonance imaging of congenital dislocation of the hip with avascular necrosis of the femoral head

International Nuclear Information System (INIS)

Hayashi, Nobuhiko; Ikeda, Takeshi; Wada, Ikuo

1991-01-01

Magnetic resonance imaging (MRI) was performed on 22 patients (24 joints) with congenital dislocation of the hip (CDH) with avascular necrosis. T1 and T2 weighted images were obtained using spin echo techniques. Since positive images of the articular cartilage were obtained, it was possible to clearly image flattening or thickening of the articular cartilage of the femoral head and acetabulum in the coronal and in the axial plane of the T1 weighted image. There was a high intensity region in the femoral head with avascular necrosis in the coronal T2 weighted image. The wideness of the region increased with severity. Much information can be obtained with MRI and it is a useful technique in evaluating the pathology of CDH with avascular necrosis. (author)

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... the head uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of the brain and other cranial structures that are clearer and more detailed than other imaging methods. This exam does not use ionizing radiation and may require an injection of a ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... necessary in trauma situations. Although there is no reason to believe that magnetic resonance imaging harms the ...

Imaging of the hip joint. Computed tomography versus magnetic resonance imaging

Science.gov (United States)

Lang, P.; Genant, H. K.; Jergesen, H. E.; Murray, W. R.

1992-01-01

The authors reviewed the applications and limitations of computed tomography (CT) and magnetic resonance (MR) imaging in the assessment of the most common hip disorders. Magnetic resonance imaging is the most sensitive technique in detecting osteonecrosis of the femoral head. Magnetic resonance reflects the histologic changes associated with osteonecrosis very well, which may ultimately help to improve staging. Computed tomography can more accurately identify subchondral fractures than MR imaging and thus remains important for staging. In congenital dysplasia of the hip, the position of the nonossified femoral head in children less than six months of age can only be inferred by indirect signs on CT. Magnetic resonance imaging demonstrates the cartilaginous femoral head directly without ionizing radiation. Computed tomography remains the imaging modality of choice for evaluating fractures of the hip joint. In some patients, MR imaging demonstrates the fracture even when it is not apparent on radiography. In neoplasm, CT provides better assessment of calcification, ossification, and periosteal reaction than MR imaging. Magnetic resonance imaging, however, represents the most accurate imaging modality for evaluating intramedullary and soft-tissue extent of the tumor and identifying involvement of neurovascular bundles. Magnetic resonance imaging can also be used to monitor response to chemotherapy. In osteoarthrosis and rheumatoid arthritis of the hip, both CT and MR provide more detailed assessment of the severity of disease than conventional radiography because of their tomographic nature. Magnetic resonance imaging is unique in evaluating cartilage degeneration and loss, and in demonstrating soft-tissue alterations such as inflammatory synovial proliferation.

Magnetic resonance imaging of avascular necrosis of the femoral head

International Nuclear Information System (INIS)

Thickman, D.; Axel, L.; Kressel, H.Y.; Velchick, M.; Dalinka, M.; Steinberg, M.; Chen, H.; Fallon, M.

1986-01-01

This study investigates the role of magnetic resonance imaging (MR) in identifying avascular necrosis (AVN) of the femoral head and in monitoring its therapy. The detection of AVN, particularly in its early stages, is imperative to give therapeutic intervention the best opportunity for successful management. The results of magnetic resonance imaging are compared with those of the standard diagnostic modalities in evaluation of patients with the lesion. Examinations were performed at 0.12 T with a repetition time (TR) of 143 ms and times to echo (TE's) of 10 or 20 ms. This study represents a retrospective review of 90 hips which were examined in 45 consecutive patients. Of these, 52 hips were biopsied as part of treatment. MR was shown to be sensitive in the detection of AVN. Comparison of MR with radionuclide imaging showed comparable sensitivity and specificity. MR was also noted to be sensitive in the detection of early AVN. Preliminary results suggest that MR can monitor treatment of the affected hip, and may even be able to predict patient response to therapy. Although further work is necessary to determine the role of MR in the evaluation of the patient presenting with hip pain, MR is a sensitive method in detecting AVN and in monitoring its course in patients suspected of having the disease. (orig.)

Magnetic resonance imaging of avascular necrosis of the femoral head

Energy Technology Data Exchange (ETDEWEB)

Thickman, D; Axel, L; Kressel, H Y; Velchick, M; Dalinka, M; Steinberg, M; Chen, H; Fallon, M

1986-02-01

This study investigates the role of magnetic resonance imaging (MR) in identifying avascular necrosis (AVN) of the femoral head and in monitoring its therapy. The detection of AVN, particularly in its early stages, is imperative to give therapeutic intervention the best opportunity for successful management. The results of magnetic resonance imaging are compared with those of the standard diagnostic modalities in evaluation of patients with the lesion. Examinations were performed at 0.12 T with a repetition time (TR) of 143 ms and times to echo (TE's) of 10 or 20 ms. This study represents a retrospective review of 90 hips which were examined in 45 consecutive patients. Of these, 52 hips were biopsied as part of treatment. MR was shown to be sensitive in the detection of AVN. Comparison of MR with radionuclide imaging showed comparable sensitivity and specificity. MR was also noted to be sensitive in the detection of early AVN. Preliminary results suggest that MR can monitor treatment of the affected hip, and may even be able to predict patient response to therapy. Although further work is necessary to determine the role of MR in the evaluation of the patient presenting with hip pain, MR is a sensitive method in detecting AVN and in monitoring its course in patients suspected of having the disease.

Averaged head phantoms from magnetic resonance images of Korean children and young adults

Science.gov (United States)

Han, Miran; Lee, Ae-Kyoung; Choi, Hyung-Do; Jung, Yong Wook; Park, Jin Seo

2018-02-01

Increased use of mobile phones raises concerns about the health risks of electromagnetic radiation. Phantom heads are routinely used for radiofrequency dosimetry simulations, and the purpose of this study was to construct averaged phantom heads for children and young adults. Using magnetic resonance images (MRI), sectioned cadaver images, and a hybrid approach, we initially built template phantoms representing 6-, 9-, 12-, 15-year-old children and young adults. Our subsequent approach revised the template phantoms using 29 averaged items that were identified by averaging the MRI data from 500 children and young adults. In females, the brain size and cranium thickness peaked in the early teens and then decreased. This is contrary to what was observed in males, where brain size and cranium thicknesses either plateaued or grew continuously. The overall shape of brains was spherical in children and became ellipsoidal by adulthood. In this study, we devised a method to build averaged phantom heads by constructing surface and voxel models. The surface model could be used for phantom manipulation, whereas the voxel model could be used for compliance test of specific absorption rate (SAR) for users of mobile phones or other electronic devices.

Magnetic resonance imaging of the central nervous system

International Nuclear Information System (INIS)

Brant-Zawadzki, M.; Norman, D.

1987-01-01

This book presents the papers on technological advancement and diagnostic uses g magnetic resonance imaging. A comparative evaluation with computerized tomography is presented. Topics covered are imaging principles g magnetic resonance;instrumentation of magnetic resonance (MR);pathophysiology;quality and limitations g images;NMR imaging of brain and spinal cord;MR spectroscopy and its applications;neuroanatomy;Congenital malformations of brain and MR imaging;planning g MR imaging of spine and head and neck imaging

Are patient specific meshes required for EIT head imaging?

Science.gov (United States)

Jehl, Markus; Aristovich, Kirill; Faulkner, Mayo; Holder, David

2016-06-01

Head imaging with electrical impedance tomography (EIT) is usually done with time-differential measurements, to reduce time-invariant modelling errors. Previous research suggested that more accurate head models improved image quality, but no thorough analysis has been done on the required accuracy. We propose a novel pipeline for creation of precise head meshes from magnetic resonance imaging and computed tomography scans, which was applied to four different heads. Voltages were simulated on all four heads for perturbations of different magnitude, haemorrhage and ischaemia, in five different positions and for three levels of instrumentation noise. Statistical analysis showed that reconstructions on the correct mesh were on average 25% better than on the other meshes. However, the stroke detection rates were not improved. We conclude that a generic head mesh is sufficient for monitoring patients for secondary strokes following head trauma.

Imaging abusive head trauma: why use both computed tomography and magnetic resonance imaging?

Energy Technology Data Exchange (ETDEWEB)

Vazquez, Elida; Delgado, Ignacio; Sanchez-Montanez, Angel [Hospital Universitario Vall d' Hebron, UAB, Pediatric Radiology Department, Barcelona (Spain); Fabrega, Anna [Hospital Universitario Vall d' Hebron, UAB, Department of Pediatrics, Barcelona (Spain); Cano, Paola [Hospital Universitario Vall d' Hebron, UAB, Pediatric Neurosurgery, Barcelona (Spain); Martin, Nieves [Hospital Universitario Vall d' Hebron, UAB, Pediatric Ophthalmology, Barcelona (Spain)

2014-12-15

Abusive head trauma is the leading cause of death in child abuse cases. The majority of victims are infants younger than 1 year old, with the average age between 3 and 8 months, although these injuries can be seen in children up to 5 years old. Many victims have a history of previous abuse and the diagnosis is frequently delayed. Neuroimaging is often crucial for establishing the diagnosis of abusive head trauma as it detects occult injury in 37% of cases. Several imaging patterns are considered to be particularly associated with abusive head trauma. The presence of subdural hematoma, especially in multiple locations, such as the interhemispheric region, over the convexity and in the posterior fossa, is significantly associated with abusive head trauma. Although CT is the recommended first-line imaging modality for suspected abusive head trauma, early MRI is increasingly used alongside CT because it provides a better estimation of shear injuries, hypoxic-ischemic insult and the timing of lesions. This article presents a review of the use and clinical indications of the most pertinent neuroimaging modalities for the diagnosis of abusive head trauma, emphasizing the newer and more sensitive techniques that may be useful to better characterize the nature and evolution of the injury. (orig.)

Imaging abusive head trauma: why use both computed tomography and magnetic resonance imaging?

International Nuclear Information System (INIS)

Vazquez, Elida; Delgado, Ignacio; Sanchez-Montanez, Angel; Fabrega, Anna; Cano, Paola; Martin, Nieves

2014-01-01

Abusive head trauma is the leading cause of death in child abuse cases. The majority of victims are infants younger than 1 year old, with the average age between 3 and 8 months, although these injuries can be seen in children up to 5 years old. Many victims have a history of previous abuse and the diagnosis is frequently delayed. Neuroimaging is often crucial for establishing the diagnosis of abusive head trauma as it detects occult injury in 37% of cases. Several imaging patterns are considered to be particularly associated with abusive head trauma. The presence of subdural hematoma, especially in multiple locations, such as the interhemispheric region, over the convexity and in the posterior fossa, is significantly associated with abusive head trauma. Although CT is the recommended first-line imaging modality for suspected abusive head trauma, early MRI is increasingly used alongside CT because it provides a better estimation of shear injuries, hypoxic-ischemic insult and the timing of lesions. This article presents a review of the use and clinical indications of the most pertinent neuroimaging modalities for the diagnosis of abusive head trauma, emphasizing the newer and more sensitive techniques that may be useful to better characterize the nature and evolution of the injury. (orig.)

Effectiveness of the magnetic resonance imaging for the therapy of avascular necrosis of the femoral head

International Nuclear Information System (INIS)

Oda, Yoshinao; Katsuki, Ichirou; Ushijima, Masahiro; Tsutsui, Hideki; Sugioka, Youichi

1990-01-01

Recently, some reports demonstrate the usefulness of the magnetic resonance imaging (MRI) for early diagnosis of the avascular necrosis of the femoral head (ANF). In this report we analyzed 64 hips in 40 cases using preoperative plain radiographs, tomography and MRI affected by ANF. And we gained following three conclusions. When rotational osteotomy of the femoral head is to be carried out, two plain views of MRI, parallel and contrary to the axis of the femoral neck, were useful for evaluation of postoperative weight bearing area. In 58 hips with strinct the former two plain views of MRI, atrophy of posterior area of the femoral head was recognized in 54 hips by tomography, and of them abnormal signal in posterior was revealed in 32 hips by MRI. In 28 hips performed anterior rotational osteotomy, atrophy of posterior area of the femoral head was recognized in 26 hips by tomography, and of them abnormal signal in posterior was revealed in 6 hips by MRI. In such cases careful follow-up should be required. (author)

Effectiveness of the magnetic resonance imaging for the therapy of avascular necrosis of the femoral head

Energy Technology Data Exchange (ETDEWEB)

Oda, Yoshinao; Katsuki, Ichirou; Ushijima, Masahiro; Tsutsui, Hideki; Sugioka, Youichi [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

1990-03-01

Recently, some reports demonstrate the usefulness of the magnetic resonance imaging (MRI) for early diagnosis of the avascular necrosis of the femoral head (ANF). In this report we analyzed 64 hips in 40 cases using preoperative plain radiographs, tomography and MRI affected by ANF. And we gained following three conclusions. When rotational osteotomy of the femoral head is to be carried out, two plain views of MRI, parallel and contrary to the axis of the femoral neck, were useful for evaluation of postoperative weight bearing area. In 58 hips with strinct the former two plain views of MRI, atrophy of posterior area of the femoral head was recognized in 54 hips by tomography, and of them abnormal signal in posterior was revealed in 32 hips by MRI. In 28 hips performed anterior rotational osteotomy, atrophy of posterior area of the femoral head was recognized in 26 hips by tomography, and of them abnormal signal in posterior was revealed in 6 hips by MRI. In such cases careful follow-up should be required. (author).

Prospective, blinded trial of whole-body magnetic resonance imaging versus computed tomography positron emission tomography in staging primary and recurrent cancer of the head and neck.

LENUS (Irish Health Repository)

O'Neill, J P

2012-02-01

OBJECTIVES: To compare the use of computed tomography - positron emission tomography and whole-body magnetic resonance imaging for the staging of head and neck cancer. PATIENTS AND METHODS: From January to July 2009, 15 consecutive head and neck cancer patients (11 men and four women; mean age 59 years; age range 19 to 81 years) underwent computed tomography - positron emission tomography and whole-body magnetic resonance imaging for pre-therapeutic evaluation. All scans were staged, as per the American Joint Committee on Cancer tumour-node-metastasis classification, by two blinded consultant radiologists, in two sittings. Diagnoses were confirmed by histopathological examination of endoscopic biopsies, and in some cases whole surgical specimens. RESULTS: Tumour staging showed a 74 per cent concordance, node staging an 80 per cent concordance and metastasis staging a 100 per cent concordance, comparing the two imaging modalities. CONCLUSION: This study found radiological staging discordance between the two imaging modalities. Whole-body magnetic resonance imaging is an emerging staging modality with superior visualisation of metastatic disease, which does not require exposure to ionising radiation.

diagnostic imaging of acute head trauma

International Nuclear Information System (INIS)

Prayer, D.; Rametsteiner, C.

2001-01-01

Computed tomography (CT) is the primary modality of choice for imaging patients with acute head trauma. Lesions of the soft tissues and of the bones can be assessed more precisely than with other imaging modalities. With magnetic resonance imaging (MRI) additional information may be gained especially in subacute and chronic posttraumatic conditions. Urgent indication to perform a CT examination depends on the patient's history and on the mechanism of trauma. Imaging interpretation has been performed in the context of typical pathologic effects of trauma and with respect to potential therapy. (author)

Magnetic resonance imaging after traumatic dislocation of the hip

International Nuclear Information System (INIS)

Takahashi, Kenji; Saegusa, Osamu; Saito, Masahito; Nishikawa, Satoru; Nishisu, Takashi; Kobayashi, Teruhisa; Shimizu, Kou.

1995-01-01

Magnetic resonance (MR) images obtained from 24 patients with traumatic dislocation of the hip was retrospectively studied. Abnormal MR images due to bone contusion appeared in a high frequency in the early phase after dislocation, and most of them normalized within 3 months after injury. Influence of bone contusion was also observed in patients with avascular necrosis of the femoral head, which made the diagnosis of avascular necrosis of the femoral head difficult. Therefore, absence of avascular necrosis of the femoral head is confirmed if normal MR images were obtained, while if there is abnormal images, careful follow-up should be continued paying special attention on the occurrence of avascular necrosis of the femoral head. (S.Y.)

Magnetic resonance imaging after traumatic dislocation of the hip

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Kenji; Saegusa, Osamu; Saito, Masahito; Nishikawa, Satoru; Nishisu, Takashi; Kobayashi, Teruhisa [Narita Red Cross Hospital, Chiba (Japan); Shimizu, Kou

1995-10-01

Magnetic resonance (MR) images obtained from 24 patients with traumatic dislocation of the hip was retrospectively studied. Abnormal MR images due to bone contusion appeared in a high frequency in the early phase after dislocation, and most of them normalized within 3 months after injury. Influence of bone contusion was also observed in patients with avascular necrosis of the femoral head, which made the diagnosis of avascular necrosis of the femoral head difficult. Therefore, absence of avascular necrosis of the femoral head is confirmed if normal MR images were obtained, while if there is abnormal images, careful follow-up should be continued paying special attention on the occurrence of avascular necrosis of the femoral head. (S.Y.).

Evaluation of Effective Parameters on Quality of Magnetic Resonance Imaging-computed Tomography Image Fusion in Head and Neck Tumors for Application in Treatment Planning

Directory of Open Access Journals (Sweden)

Atefeh Shirvani

2017-01-01

Full Text Available Background: In radiation therapy, computed tomography (CT simulation is used for treatment planning to define the location of tumor. Magnetic resonance imaging (MRI-CT image fusion leads to more efficient tumor contouring. This work tried to identify the practical issues for the combination of CT and MRI images in real clinical cases. The effect of various factors is evaluated on image fusion quality. Materials and Methods: In this study, the data of thirty patients with brain tumors were used for image fusion. The effect of several parameters on possibility and quality of image fusion was evaluated. These parameters include angles of the patient's head on the bed, slices thickness, slice gap, and height of the patient's head. Results: According to the results, the first dominating factor on quality of image fusion was the difference slice gap between CT and MRI images (cor = 0.86, P 4 cm and image fusion quality was <25%. Conclusion: The most important problem in image fusion is that MRI images are taken without regard to their use in treatment planning. In general, parameters related to the patient position during MRI imaging should be chosen to be consistent with CT images of the patient in terms of location and angle.

Computed tomography and magnetic resonance imaging findings of peripheral primitive neuroectodermal tumors of the head and neck

International Nuclear Information System (INIS)

Zhang Weidong; Chen Yanfeng; Li Chuanxing; Zhang Liang; Xu Zhibin; Zhang Fujun

2011-01-01

Purpose: We aimed to analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of peripheral primitive neuroectodermal tumor (pPNET) of the head and neck. Methods: Eight patients with pPNET of the head and neck confirmed by histopathological examination were analyzed retrospectively. Results: The average patient age was 8 years. The tumor location in the 8 patients was as follows: maxillofacial region (right, 2; left, 1), left maxillary sinus (1), right masticator space (1), left carotid space (1), right infratemporal fossa (1), and left parotid gland (1). All 5 patients who underwent CT demonstrated ill-defined soft masses and no calcification. Three patients with tumors in the maxillofacial region showed homogeneous small masses and a mild enhancement. The patient with left maxillary sinus tumor showed a heterogeneous mass with patchy, necrotic foci and mild heterogeneous enhancement. The patient with right masticator space tumor showed a heterogeneous mass, and marked heterogeneous enhancement. The T1-weighted images of the patients with right infratemporal fossa, left carotid space, and left parotid gland tumors were isointense. The T2-weighted images were heterogeneous and mildly hyperintense in 2 patients and hyperintense in 1 patient. Heterogeneous intermediate enhancement was demonstrated in 2 patients and mild ring enhancement in 1 patient. Conclusion: The imaging features of pPNET of the head and neck are non-specific. An ill-defined, aggressive mass and variable enhancement on CT and MR images may suggest the diagnosis of pPNET. Peripheral PNET should be included in the differential diagnosis of children and adolescents' regional tumors.

Computed tomography and magnetic resonance imaging findings of peripheral primitive neuroectodermal tumors of the head and neck

Energy Technology Data Exchange (ETDEWEB)

Zhang Weidong [State Key Laboratory of Oncology in South China, Department of Radiology, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510060 (China); Chen Yanfeng [State Key Laboratory of Oncology in South China, Department of Head and Neck Surgery, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510060 (China); Li Chuanxing; Zhang Liang; Xu Zhibin [State Key Laboratory of Oncology in South China, Department of Radiology, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510060 (China); Zhang Fujun, E-mail: drzhangfj@163.com [State Key Laboratory of Oncology in South China, Department of Radiology, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510060 (China)

2011-11-15

Purpose: We aimed to analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of peripheral primitive neuroectodermal tumor (pPNET) of the head and neck. Methods: Eight patients with pPNET of the head and neck confirmed by histopathological examination were analyzed retrospectively. Results: The average patient age was 8 years. The tumor location in the 8 patients was as follows: maxillofacial region (right, 2; left, 1), left maxillary sinus (1), right masticator space (1), left carotid space (1), right infratemporal fossa (1), and left parotid gland (1). All 5 patients who underwent CT demonstrated ill-defined soft masses and no calcification. Three patients with tumors in the maxillofacial region showed homogeneous small masses and a mild enhancement. The patient with left maxillary sinus tumor showed a heterogeneous mass with patchy, necrotic foci and mild heterogeneous enhancement. The patient with right masticator space tumor showed a heterogeneous mass, and marked heterogeneous enhancement. The T1-weighted images of the patients with right infratemporal fossa, left carotid space, and left parotid gland tumors were isointense. The T2-weighted images were heterogeneous and mildly hyperintense in 2 patients and hyperintense in 1 patient. Heterogeneous intermediate enhancement was demonstrated in 2 patients and mild ring enhancement in 1 patient. Conclusion: The imaging features of pPNET of the head and neck are non-specific. An ill-defined, aggressive mass and variable enhancement on CT and MR images may suggest the diagnosis of pPNET. Peripheral PNET should be included in the differential diagnosis of children and adolescents' regional tumors.

A simple rapid process for semi-automated brain extraction from magnetic resonance images of the whole mouse head.

Science.gov (United States)

Delora, Adam; Gonzales, Aaron; Medina, Christopher S; Mitchell, Adam; Mohed, Abdul Faheem; Jacobs, Russell E; Bearer, Elaine L

2016-01-15

Magnetic resonance imaging (MRI) is a well-developed technique in neuroscience. Limitations in applying MRI to rodent models of neuropsychiatric disorders include the large number of animals required to achieve statistical significance, and the paucity of automation tools for the critical early step in processing, brain extraction, which prepares brain images for alignment and voxel-wise statistics. This novel timesaving automation of template-based brain extraction ("skull-stripping") is capable of quickly and reliably extracting the brain from large numbers of whole head images in a single step. The method is simple to install and requires minimal user interaction. This method is equally applicable to different types of MR images. Results were evaluated with Dice and Jacquard similarity indices and compared in 3D surface projections with other stripping approaches. Statistical comparisons demonstrate that individual variation of brain volumes are preserved. A downloadable software package not otherwise available for extraction of brains from whole head images is included here. This software tool increases speed, can be used with an atlas or a template from within the dataset, and produces masks that need little further refinement. Our new automation can be applied to any MR dataset, since the starting point is a template mask generated specifically for that dataset. The method reliably and rapidly extracts brain images from whole head images, rendering them useable for subsequent analytical processing. This software tool will accelerate the exploitation of mouse models for the investigation of human brain disorders by MRI. Copyright © 2015 Elsevier B.V. All rights reserved.

Imaging of head and neck venous malformations

International Nuclear Information System (INIS)

Flis, Christine M.; Connor, Stephen E.

2005-01-01

Venous malformations (VMs) are non proliferative lesions that consist of dysplastic venous channels. The aim of imaging is to characterise the lesion and define its anatomic extent. We will describe the plain film, ultrasound (US) (including colour and duplex Doppler), computed tomography (CT), magnetic resonance imaging (MRI), conventional angiographic and direct phlebographic appearances of venous malformations. They will be illustrated at a number of head and neck locations, including orbit, oral cavity, superficial and deep facial space, supraglottic and intramuscular. An understanding of the classification of such vascular anomalies is required to define the correct therapeutic procedure to employ. Image-guided sclerotherapy alone or in combination with surgery is now the first line treatment option in many cases of head and neck venous malformations, so the radiologist is now an integral part of the multidisciplinary management team. (orig.)

Magnetic resonance imaging: effects of magnetic field strength

International Nuclear Information System (INIS)

Crooks, L.E.; Arakawa, M.; Hoenninger, J.; McCarten, B.; Watts, J.; Kaufman, L.

1984-01-01

Magnetic resonance images of the head, abdomen, and pelvis of normal adult men were obtained using varying magnetic field strength, and measurements of T1 and T2 relaxations and of signal-to-noise (SN) ratios were determined. For any one spin echo sequence, gray/white matter contrast decreases and muscle/fat contrast increases with field. SN levels rise rapidly up to 3.0 kgauss and then change more slowly, actually dropping for muscle. The optimum field for magnetic resonance imaging depends on tissue type, body part, and imaging sequence, so that it does not have a unique value. Magnetic resonance systems that operate in the 3.0-5.0 kgauss range achieve most or all of the gains that can be achieved by higher magnetic fields

Magnetic resonance imaging: Atlas of the head, neck and spine

International Nuclear Information System (INIS)

Mills, C.M.; De Groot, J.; Posin, J.P.

1987-01-01

The purpose of this atlas is to provide the reader with a means to complement existing sources of information and to correlate the superb soft tissue contrast realized in magnetic resonance images with the appropriate anatomic and functional structures. Where appropriate, pathologic examples have been included to complement normal images. In addition, since MRI (magnetic resonance imaging) clearly separates gray from white matter, and thus accurately visualizes the position of functional tracts as they extend from cortex to spinal cord, a separate section on functional neuroanatomy has been provided. Likewise, the improved visualization of vascular structures and associated pathologic processes has led to the inclusion of vascular anatomy and associated perfusion territories. These additions will be of particular use in clinical practice, as precise lesion identification and localization can now be correlated to specific clinical symptomatology

Evaluation of head at risk sign in legg-Calve-Perthes disease by magnetic resonance imaging

International Nuclear Information System (INIS)

Seki, Kazushige; Kaichi, Itsurou; Sugi, Mototsugu; Tanigawa, Yasuhiko

2003-01-01

Twenty-seven hips with Legg-Calve-Perthes disease were studied to evaluate head at risk signs by magnetic resonance imaging (MRI). The mean age at the first presentation was 6 years ranging from 3 years to 10 years, and the mean follow-up period was 48 months, ranging from 23 months to 96 months. There were 25 hips with lateral subluxation, 5 with calcification, 15 with metaphyseal cyst, 9 with Gage's sign, and 7 with horizontal growth plate. Lateral subluxation resulted from enlargement of the articular cartilage on MRI. Calcification existed in the enlarged lateral articular cartilage on MRI. The defect in the lateral part of the epiphysis on the radiographs called Gage's sign showed intermediate intensity on T1-weighted image and high signal intensity on T2-weighted image, suggesting that Gage's sign represents reparation at an early stage. The metaphyseal cyst presented various signal intensity on MRI, and it was thought that metaphyseal cyst involved growth plate influenced prognosis. The growth plates were not horizontal on MRI. (author)

Prospective observer and software-based assessment of magnetic resonance imaging quality in head and neck cancer: Should standard positioning and immobilization be required for radiation therapy applications?

Science.gov (United States)

Ding, Yao; Mohamed, Abdallah S R; Yang, Jinzhong; Colen, Rivka R; Frank, Steven J; Wang, Jihong; Wassal, Eslam Y; Wang, Wenjie; Kantor, Michael E; Balter, Peter A; Rosenthal, David I; Lai, Stephen Y; Hazle, John D; Fuller, Clifton D

2015-01-01

The purpose of this study was to investigate the potential of a head and neck magnetic resonance simulation and immobilization protocol on reducing motion-induced artifacts and improving positional variance for radiation therapy applications. Two groups (group 1, 17 patients; group 2, 14 patients) of patients with head and neck cancer were included under a prospective, institutional review board-approved protocol and signed informed consent. A 3.0-T magnetic resonance imaging (MRI) scanner was used for anatomic and dynamic contrast-enhanced acquisitions with standard diagnostic MRI setup for group 1 and radiation therapy immobilization devices for group 2 patients. The impact of magnetic resonance simulation/immobilization was evaluated qualitatively by 2 observers in terms of motion artifacts and positional reproducibility and quantitatively using 3-dimensional deformable registration to track intrascan maximum motion displacement of voxels inside 7 manually segmented regions of interest. The image quality of group 2 (29 examinations) was significantly better than that of group 1 (50 examinations) as rated by both observers in terms of motion minimization and imaging reproducibility (P quality of head and neck MRI in terms of motion-related artifacts and positional reproducibility was greatly improved by use of radiation therapy immobilization devices. Consequently, immobilization with external and intraoral fixation in MRI examinations is required for radiation therapy application. Copyright © 2015 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

Avascular necrosis of femoral head: findings of contrast-enhanced MR imaging

International Nuclear Information System (INIS)

Shin, Yong Moon; Kang, Heung Sik; Kim, Chu Wan; Kim, Hee Joong; Kim, Young Min

1995-01-01

To evaluate the findings and the role of contrast enhanced magnetic resonance imaging in avascular necrosis of femoral head. Sixteen patients with avascular necorsis of femoral head were examined with MRI. T1-weighted and T2-weighted image and contrast-enhanced T1-weighted images were obtained. Enhancing characteristics of the necrotic area and synovium were determined. Also a change of the disease extent after enhancement was assessed. Twenty seven avascular necrosis of the femoral head including 11 cases of bilateral lesion were detected. Fifteen cases revealed collapse of the femoral head. The portions of the lesion with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images showed contrast enhancement in 15 cases. However, the potions with low signal intensities both on T1 and T2-weighted images showed enhancement in one case. There was no significant change of the disease extent after enhancement. Synovium showed enhancement in 18 cases, and joint effusion was detected in 23 cases. Contrast enhanced MR images may be helpful in predicting histopathologic findings of avascular necrosis of the femoral head, but not useful for evaluating the extent of disease

Avascular necrosis of femoral head: findings of contrast-enhanced MR imaging

Energy Technology Data Exchange (ETDEWEB)

Shin, Yong Moon; Kang, Heung Sik; Kim, Chu Wan; Kim, Hee Joong; Kim, Young Min [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1995-06-15

To evaluate the findings and the role of contrast enhanced magnetic resonance imaging in avascular necrosis of femoral head. Sixteen patients with avascular necorsis of femoral head were examined with MRI. T1-weighted and T2-weighted image and contrast-enhanced T1-weighted images were obtained. Enhancing characteristics of the necrotic area and synovium were determined. Also a change of the disease extent after enhancement was assessed. Twenty seven avascular necrosis of the femoral head including 11 cases of bilateral lesion were detected. Fifteen cases revealed collapse of the femoral head. The portions of the lesion with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images showed contrast enhancement in 15 cases. However, the potions with low signal intensities both on T1 and T2-weighted images showed enhancement in one case. There was no significant change of the disease extent after enhancement. Synovium showed enhancement in 18 cases, and joint effusion was detected in 23 cases. Contrast enhanced MR images may be helpful in predicting histopathologic findings of avascular necrosis of the femoral head, but not useful for evaluating the extent of disease.

Cross-sectional anatomy, computed tomography and magnetic resonance imaging of the head of common dolphin (Delphinus delphis) and striped dolphin (Stenella coeruleoalba).

Science.gov (United States)

Alonso-Farré, J M; Gonzalo-Orden, M; Barreiro-Vázquez, J D; Barreiro-Lois, A; André, M; Morell, M; Llarena-Reino, M; Monreal-Pawlowsky, T; Degollada, E

2015-02-01

Computed tomography (CT) and low-field magnetic resonance imaging (MRI) were used to scan seven by-caught dolphin cadavers, belonging to two species: four common dolphins (Delphinus delphis) and three striped dolphins (Stenella coeruleoalba). CT and MRI were obtained with the animals in ventral recumbency. After the imaging procedures, six dolphins were frozen at -20°C and sliced in the same position they were examined. Not only CT and MRI scans, but also cross sections of the heads were obtained in three body planes: transverse (slices of 1 cm thickness) in three dolphins, sagittal (5 cm thickness) in two dolphins and dorsal (5 cm thickness) in two dolphins. Relevant anatomical structures were identified and labelled on each cross section, obtaining a comprehensive bi-dimensional topographical anatomy guide of the main features of the common and the striped dolphin head. Furthermore, the anatomical cross sections were compared with their corresponding CT and MRI images, allowing an imaging identification of most of the anatomical features. CT scans produced an excellent definition of the bony and air-filled structures, while MRI allowed us to successfully identify most of the soft tissue structures in the dolphin's head. This paper provides a detailed anatomical description of the head structures of common and striped dolphins and compares anatomical cross sections with CT and MRI scans, becoming a reference guide for the interpretation of imaging studies. © 2014 Blackwell Verlag GmbH.

Occult primary tumors of the head and neck: accuracy of thallium 201 single-photon emission computed tomography and computed tomography and/or magnetic resonance imaging

NARCIS (Netherlands)

van Veen, S. A.; Balm, A. J.; Valdés Olmos, R. A.; Hoefnagel, C. A.; Hilgers, F. J.; Tan, I. B.; Pameijer, F. A.

2001-01-01

To determine the accuracy of thallium 201 single-photon emission computed tomography (thallium SPECT) and computed tomography and/or magnetic resonance imaging (CT/MRI) in the detection of occult primary tumors of the head and neck. Study of diagnostic tests. National Cancer Institute, Amsterdam,

IMAGING DIAGNOSIS-MAGNETIC RESONANCE IMAGING FEATURES OF CRANIOMANDIBULAR OSTEOPATHY IN AN AIREDALE TERRIER.

Science.gov (United States)

Matiasovic, Matej; Caine, Abby; Scarpante, Elena; Cherubini, Giunio Bruto

2016-05-01

An Airedale Terrier was presented for evaluation of depression and reluctance to be touched on the head. Magnetic resonance (MR) imaging of the head was performed. The images revealed bone lesions affecting the calvarium at the level of the coronal suture and left mandibular ramus, with focal cortical destruction, expansion, and reactive new bone formation. Skull lesions were hypointense on T1-weighted sequences, hyperintense on T2-weighted sequences, and showed an intense and homogeneous enhancement after gadolinium administration. Reactive new bone formation and periosteal proliferation were confirmed histopathologically. The clinical signs, imaging findings, and histopathological examination were consistent with craniomandibular osteopathy. © 2015 American College of Veterinary Radiology.

Towards Motion-Insensitive Magnetic Resonance Imaging Using Dynamic Field Measurements

DEFF Research Database (Denmark)

Andersen, Mads

motion during scanning and update the MRI scanner in real-time such that the imaging volume follows the head motion (prospective motion correction). In this thesis, prospective motion correction is presented where head motion is determined from signals measured with an electroencephalography (EEG) cap......Magnetic resonance imaging (MRI) of the brain is frequently used for both clinical diagnosis and brain research. This is due to the great versatility of the technique and the excellent ability to distinguish different types of soft tissue. The image quality is, however, heavily degraded when...

Magnetic resonance imaging guided reirradiation of recurrent and second primary head and neck cancer.

Science.gov (United States)

Chen, Allen M; Cao, Minsong; Hsu, Sophia; Lamb, James; Mikaeilian, Argin; Yang, Yingli; Agazaryan, Nzhde; Low, Daniel A; Steinberg, Michael L

2017-01-01

To report a single-institutional experience using magnetic resonance imaging (MRI) guided radiation therapy for the reirradiation of recurrent and second cancers of the head and neck. Between October 2014 and August 2016, 13 consecutive patients with recurrent or new primary cancers of the head and neck that occurred in a previously irradiated field were prospectively enrolled in an institutional registry trial to investigate the feasibility and efficacy of MRI guided radiation therapy using a 0.35-T MRI scanner with a cobalt-60 radiation therapy source called the ViewRay system (ViewRay Inc., Cleveland, OH). Eligibility criteria included biopsy-proven evidence of recurrent or new primary squamous cell carcinoma of the head and neck, measurable disease, and previous radiation to >60 Gy. MRI guided reirradiation was delivered either using intensity modulated radiation therapy with conventional fractionation to a median dose of 66 Gy or stereotactic body radiation therapy (SBRT) using 7 to 8 Gy fractions on nonconsecutive days to a median dose of 40 Gy. Two patients (17%) received concurrent chemotherapy. The 1- and 2-year estimates of in-field control were 72% and 72%, respectively. A total of 227 daily MRI scans were obtained to guide reirradiation. The 2-year estimates of overall survival and progression-free survival were 53% and 59%, respectively. There were no treatment-related fatalities or hospitalizations. Complications included skin desquamation, odynophagia, otitis externa, keratitis and/or conjunctivitis, and 1 case of aspiration pneumonia. Our preliminary findings show that reirradiation with MRI guided radiation therapy results in effective disease control with relatively low morbidity for patients with recurrent and second primary cancers of the head and neck. The superior soft tissue resolution of the MRI scans that were used for planning and delivery has the potential to improve the therapeutic ratio.

Neural network diagnosis of avascular necrosis from magnetic resonance images

Science.gov (United States)

Manduca, Armando; Christy, Paul S.; Ehman, Richard L.

1993-09-01

We have explored the use of artificial neural networks to diagnose avascular necrosis (AVN) of the femoral head from magnetic resonance images. We have developed multi-layer perceptron networks, trained with conjugate gradient optimization, which diagnose AVN from single sagittal images of the femoral head with 100% accuracy on the training data and 97% accuracy on test data. These networks use only the raw image as input (with minimal preprocessing to average the images down to 32 X 32 size and to scale the input data values) and learn to extract their own features for the diagnosis decision. Various experiments with these networks are described.

Molecular imaging of head and neck cancers. Perspectives of PET/MRI

International Nuclear Information System (INIS)

Stumpp, P.; Kahn, T.; Purz, S.; Sabri, O.

2016-01-01

The 18 F-fluorodeoxyglucose positron emission tomography-computed tomography ( 18 F-FDG-PET/CT) procedure is a cornerstone in the diagnostics of head and neck cancers. Several years ago PET-magnetic resonance imaging (PET/MRI) also became available as an alternative hybrid multimodal imaging method. Does PET/MRI have advantages over PET/CT in the diagnostics of head and neck cancers ?The diagnostic accuracy of the standard imaging methods CT, MRI and PET/CT is depicted according to currently available meta-analyses and studies concerning the use of PET/MRI for these indications are summarized. In all studies published up to now PET/MRI did not show superiority regarding the diagnostic accuracy in head and neck cancers; however, there is some evidence that in the future PET/MRI can contribute to tumor characterization and possibly be used to predict tumor response to therapy with the use of multiparametric imaging. Currently, 18 F-FDG-PET/CT is not outperformed by PET/MRI in the diagnostics of head and neck cancers. The additive value of PET/MRI due to the use of multiparametric imaging needs to be investigated in future research. (orig.) [de

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ... Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association top ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... the head (particularly the brain) in routine clinical practice. top of page What are some common uses ... gadolinium contrast material except when absolutely necessary for medical treatment. See the MRI Safety page for more ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... the head (particularly the brain) in routine clinical practice. top of page What are some common uses ... may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... MRI) of the head uses a powerful magnetic field, radio waves and a computer to produce detailed ... there’s a possibility you are pregnant. The magnetic field is not harmful, but it may cause some ...

Role of T2 weighted magnetic resonance image in chronic phase of head injured patients

International Nuclear Information System (INIS)

Uzura, Masahiko; Taguchi, Yoshio; Watanabe, Hiroyuki; Chiba, Syunmei; Matsuzawa, Motoshi

2002-01-01

In neuroimaging studies of head injury, addition of echo planar imaging (EPI) T2-weighted images (WI) to routine MR images has been useful in demonstrating small hemorrhagic lesions as magnetic susceptibility artifacts (MSAs). MSAs are often found in the acute or subacute phases of head injured patients with diffuse axonal injury. We studied MSAs in follow-up MR images of patients with diffuse brain injury and discuss the role of EPI T2-WI in patients with chronic phase of head injured patients. This series consisted of 20 patients with diffuse brain injury diagnosed clinically. Their head CT findings were classified into Diffuse Injury I or II according to the CT classification of Marshall et al. All patients underwent long-term follow-up MR examinations. MR findings in chronic phase were divided into three categories in terms of MSAs: group A, MSAs remaining even after disappearance of small traumatic lesions in both T2-WI and fluid attenuated inversion recovery (FLAIR) images (11 cases); group B, MSA (s) that disappeared in association with disappearance of small traumatic lesions (4 cases); and group C, MSAs that remained but could not be differentiated from non-traumatic lesions such as hemorrhagic lacunae or cavernoma (5 cases). Adding EPI T2-WI to routine MR images can provide useful information in visualizing old traumatic lesions of the brain in patients with diffuse brain injury even if no neuroimaging studies in acute or subacute phase. (author)

Normal feline brain: clinical anatomy using magnetic resonance imaging.

Science.gov (United States)

Mogicato, G; Conchou, F; Layssol-Lamour, C; Raharison, F; Sautet, J

2012-04-01

The purpose of this study was to provide a clinical anatomy atlas of the feline brain using magnetic resonance imaging (MRI). Brains of twelve normal cats were imaged using a 1.5 T magnetic resonance unit and an inversion/recovery sequence (T1). Fourteen relevant MRI sections were chosen in transverse, dorsal, median and sagittal planes. Anatomic structures were identified and labelled using anatomical texts and Nomina Anatomica Veterinaria, sectioned specimen heads, and previously published articles. The MRI sections were stained according to the major embryological and anatomical subdivisions of the brain. The relevant anatomical structures seen on MRI will assist clinicians to better understand MR images and to relate this neuro-anatomy to clinical signs. © 2011 Blackwell Verlag GmbH.

Display of cross sectional anatomy by nuclear magnetic resonance imaging.

Science.gov (United States)

Hinshaw, W S; Andrew, E R; Bottomley, P A; Holland, G N; Moore, W S

1978-04-01

High definition cross-sectional images produced by a new nuclear magnetic resonance (NMR) technique are shown. The images are a series of thin section scans in the coronal plane of the head of a rabbit. The NMR images are derived from the distribution of the density of mobile hydrogen atoms. Various tissue types can be distinguished and a clear registration of gross anatomy is demonstrated. No known hazards are associated with the technique.

Magnetic resonance imaging for radiotherapy planning of brain cancer patients using immobilization and surface coils

Science.gov (United States)

Hanvey, S.; Glegg, M.; Foster, J.

2009-09-01

This study investigated the compatibility of a head and neck immobilization device with magnetic resonance imaging (MRI). The immobilization device is used to position a patient in the same way as when receiving a computed tomography (CT) scan for radiotherapy planning and radiation treatment. The advantage of using immobilization in MR is improved accuracy in CT/MR image registration enabling greater confidence in the delineation of structures. The main practical difficulty in using an immobilization device in MRI is that physical constraints make their use incompatible with head imaging coils. Within this paper we describe a method for MR imaging of the brain which allows the use of head and neck immobilization devices. By a series of image quality tests we obtained the same or better image quality as a multi-channel head coil.

MR imaging of avascular necrosis of the femoral head

Energy Technology Data Exchange (ETDEWEB)

Choi, Eun Wan; Cho, Won Soo; Hong, Hyun Sook; Lee, Hae Kyung; Choi, Deuk Lin; Kim, Ki Jung [Soonchunhyang University Hospital, Seoul (Korea, Republic of)

1993-09-15

We evaluated the magnetic resonance imaging (MRI) findings of femoral heads in 20 normal and 45 abnormal patients. The bone marrow in the healthy adults consisted of a combination of hematopoietic and fatty marrow, which showed age-related dirtribation, that is the component of fatty marrow was increased and the marrow vascularity was decreased with age. Avascular necrosis (AVN) showed a decreased bone marrow signal within an normal appearing femoral head on T1 and T2 -weighted images. In addition, we could see inhomogeneous low signal intensive (31 cases), a ring of low intensive with central normal signal intensity (25 cases), focal low signal intensity (12 case), or a band of low signal intensity (4 cases). MRI findings were abnormal in 10 cases with normal radiographic findings as well as in all the cases with abnormal ones. In conclusion, MRI should be the choice of the imaging modality for the evaluation of early bone marrow changes of AVN.

MR imaging of avascular necrosis of the femoral head

International Nuclear Information System (INIS)

Choi, Eun Wan; Cho, Won Soo; Hong, Hyun Sook; Lee, Hae Kyung; Choi, Deuk Lin; Kim, Ki Jung

1993-01-01

We evaluated the magnetic resonance imaging (MRI) findings of femoral heads in 20 normal and 45 abnormal patients. The bone marrow in the healthy adults consisted of a combination of hematopoietic and fatty marrow, which showed age-related dirtribation, that is the component of fatty marrow was increased and the marrow vascularity was decreased with age. Avascular necrosis (AVN) showed a decreased bone marrow signal within an normal appearing femoral head on T1 and T2 -weighted images. In addition, we could see inhomogeneous low signal intensive (31 cases), a ring of low intensive with central normal signal intensity (25 cases), focal low signal intensity (12 case), or a band of low signal intensity (4 cases). MRI findings were abnormal in 10 cases with normal radiographic findings as well as in all the cases with abnormal ones. In conclusion, MRI should be the choice of the imaging modality for the evaluation of early bone marrow changes of AVN

MRI (Magnetic Resonance Imaging)

Science.gov (United States)

... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Magnetic Resonance Imaging (MRI) is a medical imaging procedure for ...

Effects of breathing a hyperoxic hypercapnic gas mixture on blood oxygenation and vascularity of head-and-neck tumors as measured by magnetic resonance imaging

International Nuclear Information System (INIS)

Rijpkema, Mark; Kaanders, Johannes H.A.M.; Joosten, Frank; Kogel, Albert J. van der; Heerschap, Arend

2002-01-01

Purpose: For head-and-neck tumors, breathing a hyperoxic hypercapnic gas mixture and administration of nicotinamide has been shown to result in a significantly improved tumor response to accelerated radiotherapy (ARCON, Accelerated Radiotherapy with CarbOgen and Nicotinamide). This may be caused by improved tumor oxygenation, possibly mediated by vascular effects. In this study, both blood oxygenation and vascular effects of breathing a hyperoxic hypercapnic gas mixture (98% O 2 +2% CO 2 ) were assessed by magnetic resonance imaging (MRI) in patients with head-and-neck tumors. Methods and Materials: Tumor vascularity and oxygenation were investigated by dynamic gadolinium contrast-enhanced MRI and blood oxygen level dependent (BOLD) MRI, respectively. Eleven patients with primary head-and-neck tumors were each measured twice; with and without breathing the hyperoxic hypercapnic gas mixture. Results: BOLD MR imaging revealed a significant increase of the MRI time constant of transverse magnetization decay (T 2 *) in the tumor during hypercapnic hyperoxygenation, which correlates to a decrease of the deoxyhemoglobin concentration. No changes in overall tumor vascularity were observed, as measured by the gadolinium contrast uptake rate in the tumor. Conclusion: Breathing a hyperoxic hypercapnic gas mixture improves tumor blood oxygenation in patients with head-and-neck tumors, which may contribute to the success of the ARCON therapy

Echo Planar Diffusion-Weighted Imaging: Possibilities and Considerations with 12- and 32-Channel Head Coils

Directory of Open Access Journals (Sweden)

John N Morelli

2012-01-01

Full Text Available Interest in clinical brain magnetic resonance imaging using 32-channel head coils for signal reception continues to increase. The present investigation assesses possibilities for improving diffusion-weighted image quality using a 32-channel in comparison to a conventional 12-channel coil. The utility of single-shot (ss and an approach to readout-segmented (rs echo planar imaging (EPI are examined using both head coils. Substantial image quality improvements are found with rs-EPI. Imaging with a 32-channel head coil allows for implementation of greater parallel imaging acceleration factors or acquisition of scans at a higher resolution. Specifically, higher resolution imaging with rs-EPI can be achieved by increasing the number of readout segments without increasing echo-spacing or echo time to the degree necessary with ss-EPI - a factor resulting in increased susceptibility artifact and reduced signal-to-noise with the latter.

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain ... the web pages found at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | ...

Display of cross sectional anatomy by nuclear magnetic resonance imaging. 1978.

Science.gov (United States)

Hinshaw, W S; Andrew, E R; Bottomley, P A; Holland, G N; Moore, W S

1995-12-01

High definition cross-sectional images produced by a new nuclear magnetic resonance (NMR) technique are shown. The images are a series of thin section scans in the coronal plane of the head of a rabbit. The NMR images are derived from the distribution of the density of mobile hydrogen atoms. Various tissue types can be distinguished and a clear registration of gross anatomy is demonstrated. No known hazards are associated with the technique.

Nonhemorrhagic brain lesions detected by magnetic resonance imaging in closed head injured patients

International Nuclear Information System (INIS)

Kinoshita, Yoshihiro; Hiraide, Atsushi; Yoshioka, Toshiji; Sugimoto, Tadashi; Ichimura, Teruhisa; Saito, Akira; Ohno, Yoshioki.

1990-01-01

This study evaluated the diagnostic usefulness of magnetic resonance imaging (MRI) in 83 closed head injured patients in whom CT failed to detect focal intra or extraaxial hematoma and/or apparent brain contusion. The patients were divided into three groups on the basis of unconsciousness duration: Group 1 comprised 50 patients diagnosed as having classical cerebral concussion; group 2 comprised 19 patients who presented to the hospital with 6-hr unconsciousness and was recovered within a week; and group 3 comprised 14 patients whose unconsciousness persisted for a week or more. There was no CT evidence of abnormal findings for group 1; and intraventricular hemorrhage and subarachnoid hemorrhage were visualized on CT in 26% and 16%, respectively, for group 2 and 71% and 14% for group 3. Intraaxial nonhemorrhagic lesions were detected on T2-weighted MRI. According to high signal intensity, diffuse axonal injury and cortical contusion could be distinguished; i.e., in the former the corpus callosum, basal ganglia, or brain stem showed a high signal intensity, and in the latter the frontal, temporal, or parietal lobe adjacent to the skull showed a low signal intensity. T2-weighted MRI revealed cortical contusion in 6% for group 1, 37% for group 2, and 14% for group 3; and diffuse axonal injury in 42% for group 2 and 79% for group 3. For 62 patients with normal CT findings, diffuse axonal injury was detected in 88%. There was a good correlation between intraventricular hemorrhage on CT and diffuse axonal injury on MRI. In conclusion, T2-weighted MRI was significantly superior to CT in detecting nonhemorrhagic lesions, and it was of great help for predicting neurologic recovery in closed head injured patients without apparent focal lesions on CT. (N.K.)

Magnetic resonance imaging phenotyping of Becker muscular dystrophy.

Science.gov (United States)

Faridian-Aragh, Neda; Wagner, Kathryn R; Leung, Doris G; Carrino, John A

2014-12-01

There is little information on magnetic resonance imaging (MRI) phenotypes of Becker muscular dystrophy (BMD). This study presents the MRI phenotyping of the upper and lower extremities of a large cohort of BMD patients. In this retrospective study, MRI images of 33 BMD subjects were evaluated for severity, distribution, and symmetry of involvement. Teres major, triceps long head, biceps brachii long head, gluteus maximus, gluteus medius, vasti, adductor longus, adductor magnus, semitendinosus, semimembranosus, and biceps femoris muscles showed the highest severity and frequency of involvement. All analyzed muscles had a high frequency of symmetric involvement. There was significant variability of involvement between muscles within some muscle groups, most notably the arm abductors, posterior arm muscles, medial thigh muscles, and lateral hip rotators. This study showed a distinctive pattern of involvement of extremity muscles in BMD subjects. © 2014 Wiley Periodicals, Inc.

Cranial anatomy and detection of ischemic stroke in the cat by nuclear magnetic resonance imaging

International Nuclear Information System (INIS)

Buonanno, F.S.; Pykett, I.L.; Kistler, J.P.; Vielma, J.; Brady, T.J.; Hinshaw, W.S.; Goldman, M.R.; Newhouse, J.H.; Pohost, G.M.

1982-01-01

Proton nuclear magnetic resonance (NMR) images of cat heads were obtained using a small, experimental imaging system. As a prelude to the study of experimental ischemic brain infarction, the normal cat head was imaged for identification of anatomical features. Images of one cat which had undergone ligation of the middle cerebral artery three weeks previously showed brain changes associated with chronic ischemic stroke and compared favorably with findings on computed tomography (CT). The NMR images have millimetric spatial resolution. NMR parameters inherent in the tissues provide intensity variations and are sufficiently sensitive to yield contrast resolution surpassing that of CT

Magnetic resonance imaging of articular cartilage: ex vivo study on normal cartilage correlated with magnetic resonance microscopy

International Nuclear Information System (INIS)

Cova, M.; Frezza, F.; Pozzi-Mucelli, R.S.; Dalla-Palma, L.; Toffanin, R.; Pozzi-Mucelli, M.; Mlynarik, V.; Vittur, F.

1998-01-01

The aims of this study were (a) to compare the MR appearance of normal articular cartilage in ex vivo MR imaging (MRI) and MR microscopy (MRM) images of disarticulated human femoral heads, (b) to evaluate by MRM the topographic variations in articular cartilage of disarticulated human femoral heads, and subsequently, (c) to compare MRM images with histology. Ten disarticulated femoral heads were examined. Magnetic resonance images were obtained using spin-echo (SE) and gradient-echo (GE) sequences. Microimages were acquired on cartilage-bone cylindrical plugs excised from four regions (superior, inferior, anterior, posterior) of one femoral head, using a modified SE sequence. Both MRI and MRM images were obtained before and after a 90 rotation of the specimen, around the axis perpendicular to the examined cartilage surface. Finally, MRM images were correlated with histology. A trilaminar appearance of articular cartilage was observed with MRI and with a greater detail with MRM. A good correlation between MRI and MRM features was demonstrated. Both MRI and MRM showed a loss of the trilaminar cartilage appearance after specimen rotation, with greater evidence on MRM images. Cartilage excised from the four regions of the femoral head showed a different thickness, being thickest in the samples excised from the superior site. The MRM technique confirms the trilaminar MRI appearance of human articular cartilage, showing good correlation with histology. The loss of the trilaminar appearance of articular cartilage induced by specimen rotation suggests that this feature is partially related to the collagen-fiber orientation within the different layers. The MRM technique also shows topographic variations in thickness of human articular cartilage. (orig.)

Pediatric magnetic resonance imaging

International Nuclear Information System (INIS)

Cohen, M.D.

1986-01-01

This book defines the current clinical potential of magnetic resonance imaging and focuses on direct clinical work with pediatric patients. A section dealing with the physics of magnetic resonance imaging provides an introduction to enable clinicians to utilize the machine and interpret the images. Magnetic resonance imaging is presented as an appropriate imaging modality for pediatric patients utilizing no radiation

Magnetic resonance imaging apparatus

International Nuclear Information System (INIS)

Ehnholm, G.J.

1991-01-01

This patent describes an electron spin resonance enhanced magnetic resonance (MR) imaging (ESREMRI) apparatus able to generate a primary magnetic field during periods of nuclear spin transition excitation and magnetic resonance signal detection. This allows the generation of ESREMRI images of a subject. A primary magnetic field of a second and higher value generated during periods of nuclear spin transition excitation and magnetic resonance signal detection can be used to generate conventional MR images of a subject. The ESREMRI and native MR images so generated may be combined, (or superimposed). (author)

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... Imaging (MRI) procedure View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. ...

Nontraumatic femoral head necrosis. Classification of bone scintigraphic findings and diagnostic value of SPECT following planar imaging

Energy Technology Data Exchange (ETDEWEB)

Minoshima, Satoshi; Uchida, Yoshitaka; Anzai, Yoshimi; Uno, Kimiichi; Arimizu, Noboru [Chiba Univ. (Japan). School of Medicine

1994-09-01

This study was conducted to determine bone scintigraphic findings in nontraumatic femoral head avascular necrosis and diagnostic value of SPECT imaging following a conventional planar imaging. Forty-three femoral heads in twenty-six cases with idiopathic femoral head necrosis (n=2), systemic lupus erythematosus (n=22), aplastic anemia (n=1), and renal transplantation (n=1) were studied. The diagnosis for femoral head necrosis was based on magnetic resonance imaging as well as other diagnostic studies in all cases. Scintigraphic findings of planar and SPECT images were classified into six categories: normal (N); cold or decrease (C); partial increase with cold or decrease (PH+C); ring-like increase with a cold center (RH+C); partial increase (PH); diffuse and/or irregular increase (DH). Avascular necrosis was confirmed in twenty-four femoral heads, in which planar and SPECT images showed scintigraphic findings of N (n=3, 2), C (n=1, 3), PH+C (n=2, 8), RH+C (n=2, 3), PH (n=9, 2), and DH (n=7, 6), respectively. Femoral heads without avascular necrosis demonstrated planar and SPECT findings of N (n=16, 12), C (n=0, 6), and DH (n=3, 1), respectively. When considering C, PH+C, and RH+C as diagnostic findings for avascular necrosis, sensitivities of planar and SPECT images were 21% and 58%, and specificities were 100% and 68%, respectively. In nineteen femoral heads with normal planar findings (N), SPECT correctly identified avascular necrosis in two femoral heads and misidentified six normal femoral heads as avascular necrosis. In nineteen femoral heads with nondiagnostic abnormalities (PH, DH), SPECT correctly identified avascular necrosis in seven femoral heads and showed no false positive. Diagnostic planar findings in five femoral heads were concordant with SPECT diagnosis. These results indicate that SPECT imaging is most valuable when planar images show nondiagnostic abnormalities based on the proposed classification of scintigraphic findings. (author).

Nontraumatic femoral head necrosis. Classification of bone scintigraphic findings and diagnostic value of SPECT following planar imaging

International Nuclear Information System (INIS)

Minoshima, Satoshi; Uchida, Yoshitaka; Anzai, Yoshimi; Uno, Kimiichi; Arimizu, Noboru

1994-01-01

This study was conducted to determine bone scintigraphic findings in nontraumatic femoral head avascular necrosis and diagnostic value of SPECT imaging following a conventional planar imaging. Forty-three femoral heads in twenty-six cases with idiopathic femoral head necrosis (n=2), systemic lupus erythematosus (n=22), aplastic anemia (n=1), and renal transplantation (n=1) were studied. The diagnosis for femoral head necrosis was based on magnetic resonance imaging as well as other diagnostic studies in all cases. Scintigraphic findings of planar and SPECT images were classified into six categories: normal (N); cold or decrease (C); partial increase with cold or decrease (PH+C); ring-like increase with a cold center (RH+C); partial increase (PH); diffuse and/or irregular increase (DH). Avascular necrosis was confirmed in twenty-four femoral heads, in which planar and SPECT images showed scintigraphic findings of N (n=3, 2), C (n=1, 3), PH+C (n=2, 8), RH+C (n=2, 3), PH (n=9, 2), and DH (n=7, 6), respectively. Femoral heads without avascular necrosis demonstrated planar and SPECT findings of N (n=16, 12), C (n=0, 6), and DH (n=3, 1), respectively. When considering C, PH+C, and RH+C as diagnostic findings for avascular necrosis, sensitivities of planar and SPECT images were 21% and 58%, and specificities were 100% and 68%, respectively. In nineteen femoral heads with normal planar findings (N), SPECT correctly identified avascular necrosis in two femoral heads and misidentified six normal femoral heads as avascular necrosis. In nineteen femoral heads with nondiagnostic abnormalities (PH, DH), SPECT correctly identified avascular necrosis in seven femoral heads and showed no false positive. Diagnostic planar findings in five femoral heads were concordant with SPECT diagnosis. These results indicate that SPECT imaging is most valuable when planar images show nondiagnostic abnormalities based on the proposed classification of scintigraphic findings. (author)

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... metallic objects. Patient movement can have the same effect. A very irregular heartbeat may affect the quality of images obtained using techniques that time the imaging based on the electrical activity of ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... six weeks) before being safe for MRI examinations. Examples include but are not limited to: artificial heart ... the area to be imaged. Furthermore, the examination takes longer than other imaging modalities (typically x-ray ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... to a CD or uploaded to a digital cloud server. Currently, MRI is the most sensitive imaging ... over time. top of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... Most MRI exams are painless. However, some patients find it uncomfortable to remain still during MR imaging. ... anxious, confused or in severe pain, you may find it difficult to lie still during imaging. A ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... imaging modalities. top of page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation ... To locate a medical imaging or radiation oncology provider in your community, you can search the ACR- ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... are clearer and more detailed than other imaging methods. This exam does not use ionizing radiation and ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... claustrophobia. Newer open MRI units provide very high quality images for many types of exams. Older open MRI units may not provide this same image quality. Certain types of exams cannot be performed using ...

State of the art magnetic resonance imaging

International Nuclear Information System (INIS)

Weissman, J.D.

1987-01-01

In less than a decade Magnetic Resonance Imaging (MRI) has evolved from a laboratory demonstration to a safe and effective technique for clinical diagnosis. This evolutionary process continues. At this time 2-D and 3-D imaging of the head and body is firmly established in clinical use. Surface coil imaging, two-component chemical shift imaging, in-vivo spectroscopy and flow imaging are currently in various stages of development. The present state of the art of MRI is a function of an array of technologies: magnet, Rf coil, Rf pulse amplifier, gradient coil and driver, pulse programmer, A/D converter, computer system architecture, array processors and mass storage (both magnetic and optical). The overall product design is the result of a complex process which balances the advantages and disadvantages of each component for optimal system performance and flexibility. The author discusses the organization of a state-of-the-art MRI system. Several examples of the kinds of system interactions affecting design choices are given. (Auth.)

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... you! Do you have a personal story about radiology? Share your patient story here Images × Image Gallery ... reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of North America ( ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos ... the body and determine the presence of certain diseases. The images can then be examined on a ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... other imaging methods. This exam does not use ionizing radiation and may require an injection of a contrast ... other internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you ... not provide cost information. The costs for specific medical imaging tests, treatments and procedures may vary by geographic ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... you, notify the radiologist or technologist. It is important that you remain perfectly still while the images are being obtained, which is typically only a few seconds to a few minutes at a time. You will know when images are being recorded ...

Clinical value of somatostatin receptor imaging in patients with suspected head and neck paragangliomas

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Matthias; Dietlein, Markus; Weber, Kerstin; Moka, Detlef; Schicha, Harald [Klinik und Poliklinik fuer Nuklearmedizin, Universitaet zu Koeln, Joseph-Stelzmann-Strasse 9, 50924 Koeln (Germany); Fischer, Eva; Michel, Olaf; Stennert, Eberhard [Klinik und Poliklinik fuer Hals-, Nasen- und Ohrenheilkunde, Universitaet zu Koeln, Koeln (Germany)

2002-12-01

Paragangliomas or glomus tumours of the head and neck region are rare somatostatin receptor-expressing neuroendocrine tumours. Precise preoperative diagnosis is of special importance in order to adequately weigh the potential benefit of the operation against the inherent risks of the procedure. In this study, the clinical value of somatostatin receptor imaging was assessed in 19 patients who underwent somatostatin receptor scintigraphy because of known or suspected paraganglioma of the head and neck region. The results were compared with the results of computed tomography and/or magnetic resonance imaging, histology and clinical follow-up. [{sup 111}In-DTPA-D-Phe{sup 1}]-octreotide scintigraphy was performed 4-6 and 24 h after i.v. injection of 140-220 MBq {sup 111}In-octreotide. Whole-body and planar images as well as single-photon emission tomography images were acquired and lesions were graded according to qualitative tracer uptake. Somatostatin receptor imaging was positive in nine patients, identifying paragangliomas for the first time in three patients and recurrent disease in six patients. In one patient, a second, previously unknown paraganglioma site was identified. Negative results were obtained in ten patients. These patients included one suffering from chronic hyperplastic otitis externa, one with granuloma tissue and an organised haematoma, one with an acoustic neuroma, one with an asymmetric internal carotid artery, two with ectasia of the bulbus venae jugularis and one with a jugular vein thrombosis. In two patients with a strong family history of paraganglioma, individual involvement could be excluded. In only one patient did somatostatin receptor imaging and magnetic resonance imaging yield false negative results in respect of recurrent paraganglioma tissue. It is concluded that somatostatin receptor scintigraphy provides important information in patients with suspected paragangliomas of the head and neck region and has a strong impact on further

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... can also provide functional information (fMRI) in selected cases. MR images of the brain and other cranial structures are clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in early diagnosis and evaluation of many conditions, ...

Magnetic resonance imaging of facial muscles

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Farrugia, M.E. [Department of Clinical Neurology, University of Oxford, Radcliffe Infirmary, Oxford (United Kingdom)], E-mail: m.e.farrugia@doctors.org.uk; Bydder, G.M. [Department of Radiology, University of California, San Diego, CA 92103-8226 (United States); Francis, J.M.; Robson, M.D. [OCMR, Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford (United Kingdom)

2007-11-15

Facial and tongue muscles are commonly involved in patients with neuromuscular disorders. However, these muscles are not as easily accessible for biopsy and pathological examination as limb muscles. We have previously investigated myasthenia gravis patients with MuSK antibodies for facial and tongue muscle atrophy using different magnetic resonance imaging sequences, including ultrashort echo time techniques and image analysis tools that allowed us to obtain quantitative assessments of facial muscles. This imaging study had shown that facial muscle measurement is possible and that useful information can be obtained using a quantitative approach. In this paper we aim to review in detail the methods that we applied to our study, to enable clinicians to study these muscles within the domain of neuromuscular disease, oncological or head and neck specialties. Quantitative assessment of the facial musculature may be of value in improving the understanding of pathological processes occurring within facial muscles in certain neuromuscular disorders.

Magnetic resonance imaging of facial muscles

International Nuclear Information System (INIS)

Farrugia, M.E.; Bydder, G.M.; Francis, J.M.; Robson, M.D.

2007-01-01

Facial and tongue muscles are commonly involved in patients with neuromuscular disorders. However, these muscles are not as easily accessible for biopsy and pathological examination as limb muscles. We have previously investigated myasthenia gravis patients with MuSK antibodies for facial and tongue muscle atrophy using different magnetic resonance imaging sequences, including ultrashort echo time techniques and image analysis tools that allowed us to obtain quantitative assessments of facial muscles. This imaging study had shown that facial muscle measurement is possible and that useful information can be obtained using a quantitative approach. In this paper we aim to review in detail the methods that we applied to our study, to enable clinicians to study these muscles within the domain of neuromuscular disease, oncological or head and neck specialties. Quantitative assessment of the facial musculature may be of value in improving the understanding of pathological processes occurring within facial muscles in certain neuromuscular disorders

Children's (Pediatric) Magnetic Resonance Imaging

Science.gov (United States)

... Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) ... limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a noninvasive ...

Common site of subchondral insufficiency fractures of the femoral head based on three-dimensional magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Iwasaki, Kenyu; Yamamoto, Takuaki; Motomura, Goro; Karasuyama, Kazuyuki; Sonoda, Kazuhiko; Kubo, Yusuke; Iwamoto, Yukihide [Kyushu University, Department of Orthopaedic Surgery Graduate School of Medical Sciences, Higashi-ku, Fukuoka (Japan)

2016-01-15

The objective of this study was to investigate the common sites of subchondral insufficiency fractures of the femoral head (SIF) based on three-dimensional (3-D) reconstruction of MR images. In 33 hips of 31 consecutive patients diagnosed with SIF, 3-D reconstruction of the bone, fracture, and acetabular edge was performed using MR images. These 3-D images were used to measure the fractured areas and clarify the positional relationship between the fracture and degree of acetabular coverage. The fractured area in the anterior portion was significantly larger than in the posterior area. In 11 cases, the fractures contacted the acetabular edge and were distributed on the lateral portion. The indices of acetabular coverage (center-edge angle and acetabular head index) in these cases were less than the normal range. In the remaining 22 cases, the fractures were apart from the acetabular edge and distributed on the mediolateral centerline of the femoral head. The majority of these cases had normal acetabular coverage. The common site of SIF is the anterior portion. In addition, two types of SIF are proposed: (1) Lateral type: the contact stress between the acetabular edge and lateral portion of the femoral head causes SIF based on the insufficient acetabular coverage, and (2) Central type: the contact stress between the acetabular surface and the mediolateral center of the femoral head causes SIF independent from the insufficiency of acetabular coverage. These findings may be useful for considering the treatment and prevention of SIF. (orig.)

Children's (Pediatric) Magnetic Resonance Imaging

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Full Text Available ... Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) ... limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a noninvasive ...

Children's (Pediatric) Magnetic Resonance Imaging

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Full Text Available ... News Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging ( ... the limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a ...

An investigation of the effects of sports-related concussion in youth using functional magnetic resonance imaging and the head impact telemetry system.

Science.gov (United States)

Keightley, Michelle; Green, Stephanie; Reed, Nick; Agnihotri, Sabrina; Wilkinson, Amy; Lobaugh, Nancy

2011-01-12

One of the most commonly reported injuries in children who participate in sports is concussion or mild traumatic brain injury (mTBI). Children and youth involved in organized sports such as competitive hockey are nearly six times more likely to suffer a severe concussion compared to children involved in other leisure physical activities. While the most common cognitive sequelae of mTBI appear similar for children and adults, the recovery profile and breadth of consequences in children remains largely unknown, as does the influence of pre-injury characteristics (e.g. gender) and injury details (e.g. magnitude and direction of impact) on long-term outcomes. Competitive sports, such as hockey, allow the rare opportunity to utilize a pre-post design to obtain pre-injury data before concussion occurs on youth characteristics and functioning and to relate this to outcome following injury. Our primary goals are to refine pediatric concussion diagnosis and management based on research evidence that is specific to children and youth. To do this we use new, multi-modal and integrative approaches that will: 1. Evaluate the immediate effects of head trauma in youth. 2. Monitor the resolution of post-concussion symptoms (PCS) and cognitive performance during recovery. 3. Utilize new methods to verify brain injury and recovery. To achieve our goals, we have implemented the Head Impact Telemetry (HIT) System. (Simbex; Lebanon, NH, USA). This system equips commercially available Easton S9 hockey helmets (Easton-Bell Sports; Van Nuys, CA, USA) with single-axis accelerometers designed to measure real-time head accelerations during contact sport participation. By using telemetric technology, the magnitude of acceleration and location of all head impacts during sport participation can be objectively detected and recorded. We also use functional magnetic resonance imaging (fMRI) to localize and assess changes in neural activity specifically in the medial temporal and frontal lobes

Cardiac magnetic resonance imaging

African Journals Online (AJOL)

2011-03-06

Mar 6, 2011 ... Cardiac magnetic resonance imaging. Cardiovascular magnetic resonance imaging is becoming a routine diagnostic technique. BRUCE s sPOTTiswOOdE, PhD. MRC/UCT Medical Imaging Research Unit, University of Cape Town, and Division of Radiology, Stellenbosch University. Bruce Spottiswoode ...

Construction of tomographic head model using sectioned photographic images of cadaver

International Nuclear Information System (INIS)

Lee, Choon Sik; Lee, Jai Ki; Park, Jin Seo; Chung, Min Suk

2004-01-01

Tomographic models are currently the most complete, developed and realistic models of the human anatomy. They have been used to estimate organ doses for diagnostic radiation examination and radiotherapy treatment planning, and radiation protection. The quality of original anatomic images is a key factor to build a quality tomographic model. Computed tomography (CT) and magnetic resonance imaging (MRI) scan, from which most of current tomographic models are constructed, have their inherent shortcomings. In this study, a tomographic model of Korean adult male head was constructed by using serially sectioned photographs of cadaver. The cadaver was embedded, frozen, serially sectioned and photographed by high resolution digital camera at 0.2 mm interval. The contours of organs and tissues in photographs were segmented by several trained anatomists. The 120 segmented images of head at 2mm interval were converted into binary files and ported into Monte Carlo code to perform an example calculation of organ dose. Whole body tomographic model will be constructed by using the procedure developed in this study

Design and Experimental Evaluation of a Non-Invasive Microwave Head Imaging System for Intracranial Haemorrhage Detection.

Directory of Open Access Journals (Sweden)

A T Mobashsher

Full Text Available An intracranial haemorrhage is a life threatening medical emergency, yet only a fraction of the patients receive treatment in time, primarily due to the transport delay in accessing diagnostic equipment in hospitals such as Magnetic Resonance Imaging or Computed Tomography. A mono-static microwave head imaging system that can be carried in an ambulance for the detection and localization of intracranial haemorrhage is presented. The system employs a single ultra-wideband antenna as sensing element to transmit signals in low microwave frequencies towards the head and capture backscattered signals. The compact and low-profile antenna provides stable directional radiation patterns over the operating bandwidth in both near and far-fields. Numerical analysis of the head imaging system with a realistic head model in various situations is performed to realize the scattering mechanism of haemorrhage. A modified delay-and-summation back-projection algorithm, which includes effects of surface waves and a distance-dependent effective permittivity model, is proposed for signal and image post-processing. The efficacy of the automated head imaging system is evaluated using a 3D-printed human head phantom with frequency dispersive dielectric properties including emulated haemorrhages with different sizes located at different depths. Scattered signals are acquired with a compact transceiver in a mono-static circular scanning profile. The reconstructed images demonstrate that the system is capable of detecting haemorrhages as small as 1 cm3. While quantitative analyses reveal that the quality of images gradually degrades with the increase of the haemorrhage's depth due to the reduction of signal penetration inside the head; rigorous statistical analysis suggests that substantial improvement in image quality can be obtained by increasing the data samples collected around the head. The proposed head imaging prototype along with the processing algorithm demonstrates

Quantitative evaluation of susceptibility effects caused by dental materials in head magnetic resonance imaging

Science.gov (United States)

Strocchi, S.; Ghielmi, M.; Basilico, F.; Macchi, A.; Novario, R.; Ferretti, R.; Binaghi, E.

2016-03-01

This work quantitatively evaluates the effects induced by susceptibility characteristics of materials commonly used in dental practice on the quality of head MR images in a clinical 1.5T device. The proposed evaluation procedure measures the image artifacts induced by susceptibility in MR images by providing an index consistent with the global degradation as perceived by the experts. Susceptibility artifacts were evaluated in a near-clinical setup, using a phantom with susceptibility and geometric characteristics similar to that of a human head. We tested different dentist materials, called PAL Keramit, Ti6Al4V-ELI, Keramit NP, ILOR F, Zirconia and used different clinical MR acquisition sequences, such as "classical" SE and fast, gradient, and diffusion sequences. The evaluation is designed as a matching process between reference and artifacts affected images recording the same scene. The extent of the degradation induced by susceptibility is then measured in terms of similarity with the corresponding reference image. The matching process involves a multimodal registration task and the use an adequate similarity index psychophysically validated, based on correlation coefficient. The proposed analyses are integrated within a computer-supported procedure that interactively guides the users in the different phases of the evaluation method. 2-Dimensional and 3-dimensional indexes are used for each material and each acquisition sequence. From these, we drew a ranking of the materials, averaging the results obtained. Zirconia and ILOR F appear to be the best choice from the susceptibility artefacts point of view, followed, in order, by PAL Keramit, Ti6Al4V-ELI and Keramit NP.

Computed tomography and magnetic resonance imaging of mild head injury - is it appropriate to classify patients with glasgow coma scale score of 13 to 15 as 'mild injury'?

International Nuclear Information System (INIS)

Uchino, Y.; Saeki, N.; Yamaura, A.; Okimura, Y.; Tanaka, M.

2001-01-01

Objective. The purpose of this study is to examine the relation between Glasgow coma scale (GCS) score and findings on computed tomography (CT) and magnetic resonance (MR) imaging of patients with mild head injury presenting GCS Scores between 13 and 15. Methods. Data were collected from all consecutive patients with mild head injury who were referred to our hospital between July 1 and October 31, 1999. All patients were recommended to undergo CT and MR imaging examinations. Patients younger than 14 years of age were excluded. Results. Ninety patients were recruited into this study. CT scans were obtained in 88 patients and MR imaging were obtained in 65 patients. Of those 90 patients, 2 patients scored 13 points, 5 scored 14 points and 83 (92.2 %) 15 points. Patients with GCS score of 13 points demonstrated parenchymal lesions an both CT and MR imaging. Those with 14 points revealed absence of parenchymal abnormality an CT, but presence of parenchymal lesions an MR imaging. Patients in advanced age (chi square test, p < 0.0001), and those with amnesia (p = 0005, not significant), although scoring 15 points, revealed a tendency to abnormal intracranial lesions on CT scans. Conclusion. It is doubtful whether patients with GCS score 13 should be included in the mild head injury category, due to obvious brain damage on CT scans. MR imaging should be performed on patients with GCS score 14, since the parenchymal lesions are not clearly demonstrated an CT scans. Even if patients scored GCS 15, patients which amnesia or of advanced age should undergo CT scans at minimum, and MR imaging when available. (author)

Magnetic resonance imaging

International Nuclear Information System (INIS)

Anon.

1988-01-01

Magnetic resonance imaging (MRI) is a new and innovative technique that affords anatomic images in multiple planes and that may provide information about tissue characterization. The magnetic resonance images are obtained by placing the patient or the area of interest within a powerful, highly uniform, static magnetic field. Magnetized protons (hydrogen nuclei) within the patient align like small magnets in this field. Radiofrequency pulses are then used to create an oscillating magnetic field perpendicular to the main field. Magnetic resonance images differ from those produced by x-rays: the latter are associated with absorption of x-ray energy while magnetic resonance images are based on proton density and proton relaxation dynamics. Proton characteristics vary according to the tissue under examination and reflect its physical and chemical properties. To resolve issues regarding safety and efficacy, the Warren Grant Magnuson Clinical Center and the Office of Medical Applications of Research of the National Institutes of Health (NIH) convened a consensus conference about MRI Oct 26 through 28, 1987. At the NIH, the Consensus Development Conference brings together investigators in the biomedical sciences, clinical investigators, practicing physicians, and consumer and special interest groups to make a scientific assessment of technologies, including drugs, devices, and procedures, and to seek agreement on their safety and effectiveness

Numerical studies of radiofrequency of the electromagnetic radiation power absorption in paediatrics undergoing brain magnetic resonance imaging

Directory of Open Access Journals (Sweden)

C. Subaar

2017-07-01

Full Text Available Magnetic resonance imaging current operating frequencies are above 100 kHz which is converted to heat through resistive tissue losses during imaging. The imaging is coupled with a concurring increase in temperature in patients. Magnetic resonance imaging of the brain has seen a rising clinical request during diagnosis and therefore become imperative that its safety issues be assessed. This study modelled Pennes' classical bio-heat equation using Finite Difference Method (FDM approach and with the help of MATLAB programming language, predicted three dimensional steady state temperature distributions in patients during magnetic resonance imaging. Sixty-four paediatric patients' referred for (head brain magnetic resonance imaging scan at 37 Military Hospital and the Diagnostic Center Limited, Ghana, pre-scan and post-scan temperatures were measured at the right tympanic. The numerically steady state temperature distribution during magnetic resonance imaging shows that there is excessive temperature elevation at the skin surface of the patients. The resulting skin heating during magnetic resonance imaging can reach dangerous level which suggests that the ohmic heating of tissue is greatest at the surface and minimal at the center of the patient's brain. Though the experimental results show that patients brain temperature increase after imaging, all measured temperatures were within acceptable safe levels.

Neural network segmentation of magnetic resonance images

International Nuclear Information System (INIS)

Frederick, B.

1990-01-01

Neural networks are well adapted to the task of grouping input patterns into subsets which share some similarity. Moreover, once trained, they can generalize their classification rules to classify new data sets. Sets of pixel intensities from magnetic resonance (MR) images provide a natural input to a neural network; by varying imaging parameters, MR images can reflect various independent physical parameters of tissues in their pixel intensities. A neural net can then be trained to classify physically similar tissue types based on sets of pixel intensities resulting from different imaging studies on the same subject. This paper reports that a neural network classifier for image segmentation was implanted on a Sun 4/60, and was tested on the task of classifying tissues of canine head MR images. Four images of a transaxial slice with different imaging sequences were taken as input to the network (three spin-echo images and an inversion recovery image). The training set consisted of 691 representative samples of gray matter, white matter, cerebrospinal fluid, bone, and muscle preclassified by a neuroscientist. The network was trained using a fast backpropagation algorithm to derive the decision criteria to classify any location in the image by its pixel intensities, and the image was subsequently segmented by the classifier

Diffusion-weighted magnetic resonance imaging of femoral head osteonecrosis in two groups of patients: Legg-Perthes-Calve and Avascular necrosis.

Science.gov (United States)

Ozel, Betul Duran; Ozel, Deniz; Ozkan, Fuat; Halefoglu, Ahmet M

2016-03-01

The aim of this prospective study was to evaluate the value of diffusion-weighted magnetic resonance imaging (DW-MRI) in patients with osteonecrosis. Patients were divided into two subgroups as avascular necrosis (AVN) of femoral head for adult group and Legg-Calvé-Perthes (LCP) patients for children. Seventeen patients with femoral head AVN (mean age 42.3 years) and 17 patients with LCP (mean age 8.2 years) were included in this study. Diagnosis confirmed with clinical and other imaging procedures among the patients complaining hip pain. DW images were obtained using the single-shot echo planar sequence and had b values of 0, 500, 1000 s/mm(2). The apparent diffusion coefficient (ADC) values were measured from ADC maps in epiphysis of patients with AVN, both from metaphysis and epiphysis in patients with LCP, respectively. Mann-Whitney U test was used to compare ADC values. The mean ADC value of femoral heads (1.285 ± 0.204 × 10(-3) mm(2)/s) was increased in patients with AVN when compared to normal bone tissue (0.209 ± 0.214 × 10(-3) mm(2)/s) (p < 0.01). The mean ADC values (×10(-3) mm(2)/s) of both metaphysis (0.852 ± 0.293) and epiphysis (0.843 ± 0.332) were also increased in patients with LCP and differences were statistically significant (p < 0.01). As a result, osteonecrosis shows increased ADC values. But it is a controversial concept that DWI offers a valuable data to conventional MRI or not. However, as there are report states, there is a correlation between the stage of the disease with ADC values in the LCP disease. DWI is a fast, without-contrast administration technique and provides quantitative values additional to conventional MR techniques; we believe DWI may play an additional assistance to the diagnosis and treatment for LCP patients. Multicentric larger group studies may provide additional data to this issue.

Very low field magnetic resonance imaging

International Nuclear Information System (INIS)

Herreros, Quentin

2013-01-01

The aim of this thesis is to perform Magnetic Resonance Imaging at very low field (from 1 mT to 10 mT). A new kind of sensor called 'mixed sensor' has been used to achieve a good detectivity at low frequencies. Combining a superconducting loop and a giant magnetoresistance, those detectors have a competitive equivalent field noise compared to existing devices (Tuned coils, SQUIDs and Atomic Magnetometers). They have been combined with flux transformers to increase the coupling between the sample and the sensor. A complete study has been performed to adapt it to mixed sensors and then maximize the gain. This set has been incorporated in an existing small MRI device to test its robustness in real conditions. In parallel, several MRI sequences (GE, SE, FLASH, EPI,...) have been integrated and adapted to very low field requirements. They have been used to perform in-vivo three dimensional imaging and relaxometry studies on well known products to test their reliability. Finally, a larger setup adapted for full-head imaging has been designed and built to perform images on a larger working volume. (author) [fr

Children's (Pediatric) Magnetic Resonance Imaging

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Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses ... identify and accurately characterize diseases than other imaging methods. This detail makes MRI an invaluable tool in ...

Magnetic resonance imaging

International Nuclear Information System (INIS)

Robertson, Angus

1990-01-01

An assessment is made of the clinical benefits of expensive diagnostic technology, such as the magnetic resonance imaging. It is concluded that to most radiologists, magnetic resonance imaging has a definite place in the diagnostic scenario, especially for demonstrating central nervous system lesions in multiple sclerosis. While it is recognized that medical and financial resources are limited, it is emphasised that the cost to society must be balanced against the patient benefit. 17 refs

Remote auscultatory patient monitoring during magnetic resonance imaging

DEFF Research Database (Denmark)

Henneberg, S; Hök, B; Wiklund, L

1992-01-01

A system for patient monitoring during magnetic resonance imaging (MRI) is described. The system is based on remote auscultation of heart sounds and respiratory sounds using specially developed pickup heads that are positioned on the precordium or at the nostrils and connected to microphones via...... can be simultaneously auscultated both inside and outside the shielded MRI room by infrared transmission through a metal mesh window. Bench tests of the system show that common mode acoustic noise is suppressed by approximately 30 dB in the frequency region of interest (100-1,000 Hz), and that polymer...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site ...

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index ...

Magnetic Resonance Imaging (MRI) -- Head

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F-18 fluoride positron emission tomography/computed tomography in the diagnosis of avascular necrosis of the femoral head: Comparison with magnetic resonance imaging

Science.gov (United States)

Gayana, Shankaramurthy; Bhattacharya, Anish; Sen, Ramesh Kumar; Singh, Paramjeet; Prakash, Mahesh; Mittal, Bhagwant Rai

2016-01-01

Objective: Femoral head avascular necrosis (FHAVN) is one of the increasingly common causes of musculoskeletal disability and poses a major diagnostic and therapeutic challenge. Although radiography, scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI) have been widely used in the diagnosis of FHAVN, positron emission tomography (PET) has recently been evaluated to assess vascularity of the femoral head. In this study, the authors compared F-18 fluoride PET/CT with MRI in the initial diagnosis of FHAVN. Patients and Methods: We prospectively studied 51 consecutive patients with a high clinical suspicion of FHAVN. All patients underwent MRI and F-18 fluoride PET/CT, the time interval between the two scans being 4–10 (mean 8) days. Two nuclear medicine physicians blinded to the MRI report read the PET/CT scans. Clinical assessment was also done. Final diagnoses were made by surgical pathology or clinical and radiologic follow-up. Results: A final diagnosis of avascular necrosis (AVN) was made in 40 patients. MRI was 96.5% sensitive, 100% specific, and 98.03% accurate while PET/CT was 100% sensitive, specific, and accurate in diagnosing FHAVN. The agreement between the two imaging modalities for the diagnosis of AVN was 96.07%. Conclusion: F-18 fluoride PET/CT showed good agreement with MRI in the initial diagnosis of FHAVN and can be better than MRI in detecting early disease. PMID:26917886

F-18 fluoride positron emission tomography/computed tomography in the diagnosis of avascular necrosis of the femoral head: Comparison with magnetic resonance imaging

International Nuclear Information System (INIS)

Gayana, Shankaramurthy; Bhattacharya, Anish; Sen, Ramesh Kumar; Singh, Paramjeet; Prakash, Mahesh; Mittal, Bhagwant Rai

2016-01-01

Femoral head avascular necrosis (FHAVN) is one of the increasingly common causes of musculoskeletal disability and poses a major diagnostic and therapeutic challenge. Although radiography, scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI) have been widely used in the diagnosis of FHAVN, positron emission tomography (PET) has recently been evaluated to assess vascularity of the femoral head. In this study, the authors compared F-18 fluoride PET/CT with MRI in the initial diagnosis of FHAVN. We prospectively studied 51 consecutive patients with a high clinical suspicion of FHAVN. All patients underwent MRI and F-18 fluoride PET/CT, the time interval between the two scans being 4–10 (mean 8) days. Two nuclear medicine physicians blinded to the MRI report read the PET/CT scans. Clinical assessment was also done. Final diagnoses were made by surgical pathology or clinical and radiologic follow-up. A final diagnosis of avascular necrosis (AVN) was made in 40 patients. MRI was 96.5% sensitive, 100% specific, and 98.03% accurate while PET/CT was 100% sensitive, specific, and accurate in diagnosing FHAVN. The agreement between the two imaging modalities for the diagnosis of AVN was 96.07%. F-18 fluoride PET/CT showed good agreement with MRI in the initial diagnosis of FHAVN and can be better than MRI in detecting early disease

Magnetic Resonance Imaging (MRI) -- Head

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Radial head button holing: a cause of irreducible anterior radial head dislocation

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Shin, Su-Mi; Chai, Jee Won; You, Ja Yeon; Park, Jina [Seoul National University Seoul Metropolitan Government Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Bae, Kee Jeong [Seoul National University Seoul Metropolitan Government Boramae Medical Center, Department of Orthopedic Surgery, Seoul (Korea, Republic of)

2016-10-15

''Buttonholing'' of the radial head through the anterior joint capsule is a known cause of irreducible anterior radial head dislocation associated with Monteggia injuries in pediatric patients. To the best of our knowledge, no report has described an injury consisting of buttonholing of the radial head through the annular ligament and a simultaneous radial head fracture in an adolescent. In the present case, the radiographic findings were a radial head fracture with anterior dislocation and lack of the anterior fat pad sign. Magnetic resonance imaging (MRI) clearly demonstrated anterior dislocation of the fractured radial head through the torn annular ligament. The anterior joint capsule and proximal portion of the annular ligament were interposed between the radial head and capitellum, preventing closed reduction of the radial head. Familiarity with this condition and imaging findings will aid clinicians to make a proper diagnosis and fast decision to perform an open reduction. (orig.)

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Resonance Energy Transfer Molecular Imaging Application in Biomedicine

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NIE Da-hong1,2;TANG Gang-hua1,3

2016-11-01

Full Text Available Resonance energy transfer molecular imaging (RETI can markedly improve signal intensity and tissue penetrating capacity of optical imaging, and have huge potential application in the deep-tissue optical imaging in vivo. Resonance energy transfer (RET is an energy transition from the donor to an acceptor that is in close proximity, including non-radiative resonance energy transfer and radiative resonance energy transfer. RETI is an optical imaging technology that is based on RET. RETI mainly contains fluorescence resonance energy transfer imaging (FRETI, bioluminescence resonance energy transfer imaging (BRETI, chemiluminescence resonance energy transfer imaging (CRETI, and radiative resonance energy transfer imaging (RRETI. RETI is the hot field of molecular imaging research and has been widely used in the fields of biology and medicine. This review mainly focuses on RETI principle and application in biomedicine.

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Full Text Available ... provides detailed images of blood vessels in the brain—often without the need for contrast material. See the MRA page for more information. MRI can detect stroke at a very early stage by mapping the motion of water molecules in the tissue. ...

Magnetic resonance imaging - first human images in Australia

International Nuclear Information System (INIS)

Baddeley, H.; Doddrell, D.M.; Brooks, W.M.; Field, J.; Irving, M.; Williams, J.E.

1986-01-01

The use of magnetic resonance imaging, in the demonstration of internal human anatomy and in the diagnosis of disease, has the major advantages that the technique is non-invasive, does not require the use of ionizing radiation and that it can demonstrate neurological and cardiovascular lesions that cannot be diagnosed easily by other imaging methods. The first magnetic resonance images of humans were obtained in Australia in October 1985 on the research instrument of the Queensland Medical Magnetic Resonance Research Centre, which is based at the Mater Hospital in Brisbane

Correlation between internal derangement and osteoarthrosis in the temporomandibular joint using magnetic resonance imaging

International Nuclear Information System (INIS)

Song, Haeng Un; Choi, Sun Young; Koh, Kwang Joon

2002-01-01

To evaluate the relationship between internal derangement and osteoarthrosis in the temporomandibular joint (TMJ) using magnetic resonance imaging (MRI). One hundred and six MR images of TMJs in 53 patients were evaluated. Disc displacements and osseous changes of the TMJs were assessed. Lateral and rotational disc displacements were also evaluated on coronal images. No significant differences in the frequency of osseous changes of the TMJs between disc displacement with reduction and disc displacement without reduction groups were found. The erosion of the condylar head and the sclerosis of the articular eminence were more frequent in the internal derangement group than in the no disc displacement group. The flattening was the most frequently observed osseous change of both the condylar head and articular eminence. The relationship between internal derangement and osteoarthrosis is obscure, but it is thought that both disorders adversely affect each other.

Correlation between internal derangement and osteoarthrosis in the temporomandibular joint using magnetic resonance imaging

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Song, Haeng Un; Choi, Sun Young; Koh, Kwang Joon [School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of)

2002-12-15

To evaluate the relationship between internal derangement and osteoarthrosis in the temporomandibular joint (TMJ) using magnetic resonance imaging (MRI). One hundred and six MR images of TMJs in 53 patients were evaluated. Disc displacements and osseous changes of the TMJs were assessed. Lateral and rotational disc displacements were also evaluated on coronal images. No significant differences in the frequency of osseous changes of the TMJs between disc displacement with reduction and disc displacement without reduction groups were found. The erosion of the condylar head and the sclerosis of the articular eminence were more frequent in the internal derangement group than in the no disc displacement group. The flattening was the most frequently observed osseous change of both the condylar head and articular eminence. The relationship between internal derangement and osteoarthrosis is obscure, but it is thought that both disorders adversely affect each other.

Magnetic Resonance Imaging (MRI) Safety

Science.gov (United States)

... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining ...

A PET/CT-based strategy is a stronger predictor of survival than a standard imaging strategy in patients with head and neck squamous cell carcinoma

DEFF Research Database (Denmark)

Rohde, Max; Nielsen, Anne L; Pareek, Manan

2018-01-01

Purpose: To examine whether tumor staging by upfront (18)F-fluoro-deoxy-glucose-positron emission tomography/computed tomography (PET/CT) leads to improved discrimination of survival, when compared with traditionally used imaging strategies based on chest X-ray + head and neck magnetic resonance...... imaging (CXR/MRI) or chest computed tomography + head and neck MRI (CCT/MRI) in patients with head and neck squamous cell carcinoma (HNSCC). Methods: Blinded prospective cohort study based on paired data. Consecutive patients with histologically verified primary HNSCC were recruited at Odense University...

Relative volume measured with magnetic resonance imaging is an articular collapse predictor in hematological pediatric patients with femoral head osteonecrosis.

Science.gov (United States)

Ippolito, Davide; Masetto, Alessandro; Talei Franzesi, Cammillo; Bonaffini, Pietro A; Casiraghi, Alessandra; Sironi, Sandro

2016-08-28

To assess the potential value of femoral head (FH) volume measurements to predict joint collapse, as compared to articular surface involvement, in post-treatment osteonecrosis (ON) in pediatric patients affected by lymphoproliferative diseases. Considering 114 young patients with lymphoproliferative diseases undergone a lower-limbs magnetic resonance imaging (MRI) examination between November 2006 and August 2012 for a suspected post-treatment ON, we finally considered a total of 13 cases (7 males, mean age 15.2 ± 4.8 years), which developed a FH ON lesions (n = 23). The MRI protocol included coronal short tau inversion recovery and T1-weighted sequences, from the hips to the ankles. During the follow-up (elapsed time: 9.2 ± 2 mo), 13/23 FH articular surface (FHS) developed articular deformity. The first MRI studies with diagnosis of ON were retrospectively analyzed, measuring FH volume (FHV), FHS, ON volume (ONV) and the articular surface involved by ON (ONS). The relative involvement of FHS, in terms of volume [relative volume (RV): ONV/FHV] and articular surface [relative surface (RS): ONS/FHS], was then calculated. By using receiver operating characteristic curve analysis (threshold of 23% of volume involvement), RV predicted articular deformity in 13/13 FHS [sensitivity 100%, specificity 90%, accuracy 95%, positive predictive value (PPV) 93%, negative predictive value (NPV) 100%]. Considering a threshold of 50% of articular involvement, RS predicted articular deformity in 10/13 femoral heads (sensitivity 77%, specificity 100%, accuracy 87%, PPV 100%, NPV 77%). RV might be a more reliable parameter than RS in predicting FH deformity and could represent a potential complementary diagnostic tool in the follow-up of femoral heads ON lesions.

Magnetic Resonance Imaging (MRI) -- Head

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Full Text Available ... navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... the equipment look like? How does the procedure work? How is the ... use to diagnose medical conditions. MRI uses a powerful magnetic field, radio frequency ...

Bone marrow oedema on MR imaging indicates ARCO stage 3 disease in patients with AVN of the femoral head.

Science.gov (United States)

Meier, Reinhard; Kraus, Tobias M; Schaeffeler, Christoph; Torka, Sebastian; Schlitter, Anna Melissa; Specht, Katja; Haller, Bernhard; Waldt, Simone; Rechl, Hans; Rummeny, Ernst J; Woertler, Klaus

2014-09-01

To test the hypothesis that bone marrow oedema (BME) observed on MRI in patients with avascular necrosis (AVN) of the femoral head represents an indicator of subchondral fracture. Thirty-seven symptomatic hips of 27 consecutive patients (53% women, mean age 49.2) with AVN of the femoral head and associated BME on magnetic resonance (MR) imaging were included. MR findings were correlated with computed tomography (CT) of the hip and confirmed by histopathological examination of the resected femoral head. Imaging studies were analysed by two radiologists with use of the ARCO classification. On MR imaging a fracture line could be identified in 19/37 (51%) cases, which were classified as ARCO stage 3 (n = 15) and stage 4 (n = 4). The remaining 18/37 (49%) cases were classified as ARCO stage 2. However, in all 37/37 (100%) cases a subchondral fracture was identified on CT, indicating ARCO stage 3/4 disease. The extent of subchondral fractures and the femoral head collapse was graded higher on CT as compared to MRI (P AVN, BME of the femoral head represents a secondary sign of subchondral fracture and thus indicates ARCO stage 3 disease. BME on MRI in AVN of femoral head indicates a subchondral fracture. BME in AVN of the femoral head represents ARCO stage 3/4 disease. CT identifies subchondral fractures and femoral head collapse better than MR imaging. This knowledge helps to avoid understaging and to trigger adequate treatment.

Magnetic Resonance Imaging of Stroke

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Bouts, Mark. J. R. J.; Wu, O.; Dijkhuizen, R. M.

2017-01-01

Magnetic resonance imaging (MRI) provides a powerful (neuro)imaging modality for the diagnosis and outcome prediction after (acute) stroke. Since MRI allows noninvasive, longitudinal, and three-dimensional assessment of vessel occlusion (with magnetic resonance angiography (MRA)), tissue injury

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Full Text Available ... radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will share the results with you. Follow-up examinations may be necessary. Your doctor will ... exam is requested. Sometimes a follow-up exam is done because a potential ...

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Full Text Available ... types of clips used for brain aneurysms some types of metal coils placed within blood vessels nearly all cardiac defibrillators and pacemakers You ... called MR angiography (MRA) provides detailed images of blood vessels in the ... the opening of certain types of MRI machines. The presence of an implant ...

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Full Text Available ... fitting and has no metal fasteners. Guidelines about eating and drinking before an MRI exam vary with the specific exam and with the imaging facility. Unless you are told otherwise, you may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ...

Magnetic Resonance Imaging. Chapter 15

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Leach, M. O. [The Institute of Cancer Research and The Royal Marsden Hospital, London (United Kingdom)

2014-09-15

In Chapter 14, the principles of nuclear magnetic resonance were presented, along with an introduction to image forming processes. In this chapter, magnetic resonance imaging (MRI) will be reviewed, beginning with the hardware needed and its impact on image quality. The acquisition processes and image reconstruction will be discussed, as well as the artefacts that are possible, with discussion of the important area of safety and bioeffects completing the chapter.

Evaluation of Blalock-Taussig shunts using magnetic resonance imaging

International Nuclear Information System (INIS)

Okajima, Yoshitomo; Tashima, Kazuyuki; Terai, Masaru; Niwa, Koichirou.

1988-01-01

Four patients aged 3 to 18 months (mean 13 months) with a total of five Blalock-Taussig shunts (BT shunts; two were original BT shunts and three were modified BT shunts using GOLASKI grafts) underwent evaluation by ECG-gated magnetic resonance imaging. There were two cases with pulmonary atresia with intact ventricular septum, one with double outlet right ventricle with pulmonary stenosis and one with tetralogy of Fallot with pulmonary atresia who underwent bilateral BT shunts. At the time of study, an auscultory shunt murmur was audible in all patients. The magnetic resonance images were obtained with a Picker International Vista MR with a superconducting magnet operating at 0.5 Tesla. A spin echo sequence (echo time 40 msec) was used. All patients were placed within a 30 cm head coil radio antenna and sedated with chloral hydrate or diazepam. Four of 5 shunts were imaged on both coronal sections and sagittal sections during enddiastole. And there was no signal within the grafts. When the velocity of blood flow is beyond the cutoff velocity, the signal intensity of flowing blood is near background level. So we judged these grafts were patient. Our results showed that MRI was a very useful noninvasive method for evaluation of BT shunts. (author)

Evaluation of Blalock-Taussig shunts using magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Okajima, Yoshitomo; Tashima, Kazuyuki; Terai, Masaru; Niwa, Koichirou.

1988-10-01

Four patients aged 3 to 18 months (mean 13 months) with a total of five Blalock-Taussig shunts (BT shunts; two were original BT shunts and three were modified BT shunts using GOLASKI grafts) underwent evaluation by ECG-gated magnetic resonance imaging. There were two cases with pulmonary atresia with intact ventricular septum, one with double outlet right ventricle with pulmonary stenosis and one with tetralogy of Fallot with pulmonary atresia who underwent bilateral BT shunts. At the time of study, an auscultory shunt murmur was audible in all patients. The magnetic resonance images were obtained with a Picker International Vista MR with a superconducting magnet operating at 0.5 Tesla. A spin echo sequence (echo time 40 msec) was used. All patients were placed within a 30 cm head coil radio antenna and sedated with chloral hydrate or diazepam. Four of 5 shunts were imaged on both coronal sections and sagittal sections during enddiastole. And there was no signal within the grafts. When the velocity of blood flow is beyond the cutoff velocity, the signal intensity of flowing blood is near background level. So we judged these grafts were patient. Our results showed that MRI was a very useful noninvasive method for evaluation of BT shunts.

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses a powerful ... for an MRI exam contains a metal called gadolinium . Gadolinium can be used in patients with iodine ...

Diffusion-Weighted Magnetic Resonance Imaging Early After Chemoradiotherapy to Monitor Treatment Response in Head-and-Neck Squamous Cell Carcinoma

Energy Technology Data Exchange (ETDEWEB)

Vandecaveye, Vincent, E-mail: Vincent.Vandecaveye@uzleuven.be [Department of Radiology, University Hospitals Leuven (Belgium); Dirix, Piet [Department of Radiation Oncology, Leuven Cancer Institute, University Hospitals Leuven (Belgium); De Keyzer, Frederik; Op de Beeck, Katya [Department of Radiology, University Hospitals Leuven (Belgium); Vander Poorten, Vincent [Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals Leuven (Belgium); Hauben, Esther [Department of Pathology, University Hospitals Leuven (Belgium); Lambrecht, Maarten; Nuyts, Sandra [Department of Radiation Oncology, Leuven Cancer Institute, University Hospitals Leuven (Belgium); Hermans, Robert [Department of Radiology, University Hospitals Leuven (Belgium)

2012-03-01

Purpose: To evaluate diffusion-weighted imaging (DWI) for assessment of treatment response in head and neck squamous cell carcinoma (HNSCC) three weeks after the end of chemoradiotherapy (CRT). Methods and Materials: Twenty-nine patients with HNSCC underwent magnetic resonance imaging (MRI) prior to and 3 weeks after CRT, including T{sub 2}-weighted and pre- and postcontrast T{sub 1}-weighted sequences and an echo-planar DWI sequence with six b values (0 to 1,000 s/mm{sup 2}), from which the apparent diffusion coefficient (ADC) was calculated. ADC changes 3 weeks posttreatment compared to baseline ( Increment ADC) between responding and nonresponding primary lesions and adenopathies were correlated with 2 years locoregional control and compared with a Mann-Whitney test. In a blinded manner, the Increment ADC was compared to conventional MRI 3 weeks post-CRT and the routinely implemented CT, on average 3 months post-CRT, which used size-related and morphological criteria. Positive and negative predictive values (PPV and NPV, respectively) were compared between the Increment ADC and anatomical imaging. Results: The Increment ADC of lesions with later tumor recurrence was significantly lower than lesions with complete remission for both primary lesions (-2.3% {+-} 0.3% vs. 80% {+-} 41%; p < 0.0001) and adenopathies (19.9% {+-} 32% vs. 63% {+-} 36%; p = 0.003). The Increment ADC showed a PPV of 89% and an NPV of 100% for primary lesions and a PPV of 70% and an NPV of 96% for adenopathies per neck side. DWI improved PPV and NPV compared to anatomical imaging. Conclusion: DWI with the Increment ADC 3 weeks after concluding CRT for HNSCC allows for early assessment of treatment response.

Strategy for magnetic resonance imaging of the head: results of a semi-empirical model. Part 1

International Nuclear Information System (INIS)

Droege, R.T.; Wiener, S.N.; Rzeszotarski, M.S.

1984-01-01

This paper is an introduction to lesion detection problems of MR. A mathematical model previously developed for normal anatomy has been extended to predict the appearance of any hypothetical lesion in magnetic (MR) images of the head. The model is applied to selected clinical images to demonstrate the loss of lesion visibility attributable to ''crossover'' and ''boundary effect.'' The model is also used to explain the origins of these problems, and to demonstrate that appropriate gray-scale manipulations can remedy these problems

Serial Head and Brain Imaging of 17 Fetuses With Confirmed Zika Virus Infection in Colombia, South America.

Science.gov (United States)

Parra-Saavedra, Miguel; Reefhuis, Jennita; Piraquive, Juan Pablo; Gilboa, Suzanne M; Badell, Martina L; Moore, Cynthia A; Mercado, Marcela; Valencia, Diana; Jamieson, Denise J; Beltran, Mauricio; Sanz-Cortes, Magda; Rivera-Casas, Ana Maria; Yepez, Mayel; Parra, Guido; Ospina Martinez, Martha; Honein, Margaret A

2017-07-01

To evaluate fetal ultrasound and magnetic resonance imaging findings among a series of pregnant women with confirmed Zika virus infection to evaluate the signs of congenital Zika syndrome with respect to timing of infection. We conducted a retrospective case series of pregnant women referred to two perinatal clinics in Barranquilla and Ibagué, Colombia, who had findings consistent with congenital Zika syndrome and Zika virus infection confirmed in maternal, fetal, or neonatal samples. Serial ultrasound measurements, fetal magnetic resonance imaging results, laboratory results, and perinatal outcomes were evaluated. We describe 17 cases of confirmed prenatal maternal Zika virus infection with adverse fetal outcomes. Among the 14 symptomatic women, the median gestational age for maternal Zika virus symptoms was 10 weeks (range 7-14 weeks of gestation). The median time between Zika virus symptom onset and microcephaly (head circumference less than 3 standard deviations below the mean) was 18 weeks (range 15-24 weeks). The earliest fetal head circumference measurement consistent with microcephaly diagnosis was at 24 weeks of gestation. The earliest sign of congenital Zika syndrome was talipes equinovarus, which in two patients was noted first at 19 weeks of gestation. Common findings on fetal magnetic resonance imaging were microcephaly, ventriculomegaly, polymicrogyria, and calcifications. Our analysis suggests a period of at least 15 weeks between maternal Zika virus infection in pregnancy and development of microcephaly and highlights the importance of serial and detailed neuroimaging.

Magnetic Resonance Imaging Appearance of Schwannomas from Head to Toe: A Pictorial Review

Directory of Open Access Journals (Sweden)

Jamie Crist

2017-01-01

Full Text Available Schwannomas are benign soft-tissue tumors that arise from peripheral nerve sheaths throughout the body and are commonly encountered in patients with neurofibromatosis Type 2. The vast majority of schwannomas are benign, with rare cases of malignant transformation reported. In this pictorial review, we discuss the magnetic resonance imaging (MRI appearance of schwannomas by demonstrating a collection of tumors from different parts of the body that exhibit similar MRI characteristics. We review strategies to distinguish schwannomas from malignant soft-tissue tumors while exploring the anatomic and histologic origins of these tumors to discuss how this correlates with their imaging findings. Familiarity with the MRI appearance of schwannomas can help aid in the differential diagnosis of soft-tissue masses, especially in unexpected locations.

Magnetic resonance imaging of the prostate

DEFF Research Database (Denmark)

Iversen, P; Kjaer, L; Thomsen, C

1988-01-01

Magnetic resonance imaging offers new possibilities in investigation of the prostate gland. Current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be useful in the staging of carcinoma of the prostate....

Diagnostic imaging of psoriatic arthritis. Part II: magnetic resonance imaging and ultrasonography

Directory of Open Access Journals (Sweden)

Iwona Sudoł-Szopińska

2016-06-01

Full Text Available Plain radiography reveals specific, yet late changes of advanced psoriatic arthritis. Early inflammatory changes are seen both on magnetic resonance imaging and ultrasound within peripheral joints (arthritis, synovitis, tendons sheaths (tenosynovitis, tendovaginitis and entheses (enthesitis, enthesopathy. In addition, magnetic resonance imaging enables the assessment of inflammatory features in the sacroiliac joints (sacroiliitis, and the spine (spondylitis. In this article, we review current opinions on the diagnostics of some selective, and distinctive features of psoriatic arthritis concerning magnetic resonance imaging and ultrasound and present some hypotheses on psoriatic arthritis etiopathogenesis, which have been studied with the use of magnetic resonance imaging. The following elements of the psoriatic arthritis are discussed: enthesitis, extracapsular inflammation, dactylitis, distal interphalangeal joint and nail disease, and the ability of magnetic resonance imaging to differentiate undifferentiated arthritis, the value of whole-body magnetic resonance imaging and dynamic contrast-enhanced magnetic resonance imaging.

Magnetic resonance imaging the basics

CERN Document Server

Constantinides, Christakis

2014-01-01

Magnetic resonance imaging (MRI) is a rapidly developing field in basic applied science and clinical practice. Research efforts in this area have already been recognized with five Nobel prizes awarded to seven Nobel laureates in the past 70 years. Based on courses taught at The Johns Hopkins University, Magnetic Resonance Imaging: The Basics provides a solid introduction to this powerful technology. The book begins with a general description of the phenomenon of magnetic resonance and a brief summary of Fourier transformations in two dimensions. It examines the fundamental principles of physics for nuclear magnetic resonance (NMR) signal formation and image construction and provides a detailed explanation of the mathematical formulation of MRI. Numerous image quantitative indices are discussed, including (among others) signal, noise, signal-to-noise, contrast, and resolution. The second part of the book examines the hardware and electronics of an MRI scanner and the typical measurements and simulations of m...

Magnetic resonance imaging of the prostate

DEFF Research Database (Denmark)

Iversen, P; Kjaer, L; Thomsen, C

1987-01-01

Magnetic resonance imaging offers new possibilities in the investigation of the prostate. The current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be of value in the staging of carcinoma of the prostate....

Imaging with 11B of intact tissues using magnetic resonance gradient echoes

International Nuclear Information System (INIS)

Richards, T.L.; Bradshaw, K.M.; Freeman, D.M.; Sotak, C.H.; Gavin, P.R.

1988-01-01

Boron neutron capture therapy (BNCT) is a proposed method of treating Glioblastoma Multiforme. BNCT is based on 10 B intake by the tumor and in-situ activation by neutron beam. It is estimated that to have successful BNCT, a 10 B delivery mechanism must deposit 20 ppM or more of 10 B within the tumor. To study and understand this delivery mechanism, 11 B can be used instead of 10 B. The pharmacokinetics of any compound using 11 B will be the same as 10 B. The advantage of using 11 B over 10 B is its greater nuclear magnetic resonance sensitivity for both spectroscopy and imaging. The use of 11 B imaging to detect and quantitate boron uptake non-invasively in animal tumor modes will facilitate continued work with 10 B. Preliminary work has shown that 11 B nuclear magnetic resonance (NMR) spectroscopy (nonlocalized) can detect 11 B in intact mouse tissues and the area under the boron peak correlates with the total boron content (correlation coefficient of 0.997). Once the ability to non-invasively measure the boron compound is established using magnetic resonance imaging (MRI) combined with spectroscopy, we will be able to address the following questions: (1) what is the optimum method of boron administration for maximum tumor selective uptake, (2) at what time is peak tumor boron concentration after infusion, and (3) what is the dose distribution in the head (based on neutron radiation and boron concentration)? The purpose of this study was to test the feasibility of imaging 11 B in intact tissues using magnetic resonance

Multi-modality image reconstruction for dual-head small-animal PET

International Nuclear Information System (INIS)

Huang, Chang-Han; Chou, Cheng-Ying

2015-01-01

The hybrid positron emission tomography/computed tomography (PET/CT) or positron emission tomography/magnetic resonance imaging (PET/MRI) has become routine practice in clinics. The applications of multi-modality imaging can also benefit research advances. Consequently, dedicated small-imaging system like dual-head small-animal PET (DHAPET) that possesses the advantages of high detection sensitivity and high resolution can exploit the structural information from CT or MRI. It should be noted that the special detector arrangement in DHAPET leads to severe data truncation, thereby degrading the image quality. We proposed to take advantage of anatomical priors and total variation (TV) minimization methods to reconstruct PET activity distribution form incomplete measurement data. The objective is to solve the penalized least-squares function consisted of data fidelity term, TV norm and medium root priors. In this work, we employed the splitting-based fast iterative shrinkage/thresholding algorithm to split smooth and non-smooth functions in the convex optimization problems. Our simulations studies validated that the images reconstructed by use of the proposed method can outperform those obtained by use of conventional expectation maximization algorithms or that without considering the anatomical prior information. Additionally, the convergence rate is also accelerated.

Malignant tumors of the nasal cavity: computed tomography and magnetic resonance imaging

International Nuclear Information System (INIS)

Souza, Ricardo Pires de; Paes Junior, Ademar Jose de Oliveira; Gonzalez, Fabio Mota; Cordeiro, Flamarion de Barros; Yamashiro, Ilka; Lenh, Carlos Neutzling; Rapoport, Abrao

2004-01-01

The aim of this study is to evaluate the role of computed tomography and magnetic resonance imaging in the characterization of deep tissue extension of malignant tumors of the nasal cavity. Twelve patients diagnosed with malignant tumors of the nasal cavity were retrospectively evaluated at the Departments of Diagnostic Imaging and Head and Neck Surgery of the 'Complexo Hospitalar Heliopolis', Sao Paulo, Brazil, between 1990 and 2000. All cases were confirmed by histopathologic examination. The results were: extension to the maxillary and ethmoid sinuses was identified in six patients, extension to contralateral nasal cavity, orbit and lamina cribosa in five patients, extension to nasal pharynx and masticator space in two patients, extension to cavernous sinus, anterior/middle cranial fossa, pterygomaxillary fossa, inferior/superior orbital fissure, frontal sinus, contralateral ethmoid sinus, contralateral lamina cribosa, hard palate and pterygopalatine fossa in one patient. Conclusion: It is important to precisely assess the local extension and spread of tumor by computed tomography and magnetic resonance imaging in order to plan the approach to treatment, which will influence the prognosis. (author)

Imaging and histopathological evaluation of a cystlike formation in subchondral insufficiency fracture of the femoral head: A case report and literature review.

Science.gov (United States)

Fukui, Kiyokazu; Kaneuji, Ayumi; Fukushima, Mana; Matsumoto, Tadami

2014-01-01

In the majority of subchondral insufficiency fractures (SIFs) of the femoral head, T1-weighted magnetic resonance imaging shows an irregular, serpiginous, low-intensity band that is convex to the articular surface. We report a case of a cystlike formation in SIF of the femoral head in an elderly woman. A 71-year-old woman reported right hip pain without any history of antecedent trauma. The initial radiograph showed a slight narrowing of the joint space in the right hip. The patient was treated with conservative therapy for 2 months. Radiographs obtained 3 months after the onset of pain showed non-progressive joint-space narrowing. T1-weighted magnetic resonance images obtained 2 months after pain onset revealed a round, cystlike, low-intensity area just beneath the articular cartilage. The patient underwent total hip arthroplasty. Histopathological examination showed fracture callus and granulation tissue in the subchondral area, surrounded by vascular-rich granulation tissue and fibrous tissue, which corresponded to the round, low-intensity band observed on the T1-weighted image. This case was a rare SIF of the femoral head which had a cystlike formation with a low signal intensity on T1-weighted images and a very high signal intensity on STIR sequences in the superolateral portion of the femoral head, surrounded by a pattern of edema in the bone marrow. To our knowledge, no similar cases were cited in the literature. It is important for surgeons to keep in mind that sometimes SIFs of the femoral head can appear as a round cystlike formation. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effect of magnetic resonance imaging on near visual acuity Efecto de la resonancia magnética sobre la agudeza visual cercana

OpenAIRE

José David Paulo Trujillo; Juan Carlos Vergara; Jorge Hernando Donado Gómez; Luz Marina Agudelo; Mercedes Cecilia Molina Betancur; Andrés Ignacio Arbeláez Medina; Carlos Andrés Molina Betancur

2007-01-01

Purpose: To determine the variation of near visual acuity, in patients exposed during short periods to intense magnetic fields in studies of magnetic resonance imaging. Methods: Descriptive study of a case series that included 40 healthy and literate individuals older than 40 years, nine of them men, submitted to a procedure of head and neck magnetic resonance imaging; all of them had near visual acuity better than 20/200 without glasses, and were not under the effects of ansiolytic medicatio...

Rapid magnetic resonance imaging protocol for detecting femoral head avascular necrosis: A case series-it′s utility in the general population in developing countries

Directory of Open Access Journals (Sweden)

M Sanjay Khaladkar

2015-01-01

Full Text Available Introduction: Osteonecrosis of the femoral head is an increasing cause of musculoskeletal disability, common among the younger population, between the third and fifth decade of life, affecting mainly men, thereby requiring prompt diagnosis and early intervention. Aims and Objectives: The aim was to formulate a limited magnetic resonance imaging (MRI examination protocol for detection of avascular necrosis (AVN in clinically suspected cases that can be performed rapidly and will be inexpensive. Materials and Methods: Forty-five patients suspected clinically and or on conventional radiography for AVN of the femoral head were referred for MRI hip. MRI hip was done on 1.5 T Siemens Avanto. Of 45, 36 were detected to have AVN (total 58 hips, whereas 9 did not have AVN on MRI. Initially, coronal T1-weighted image (T1WI sequence was obtained as limited MRI protocol, followed by complete MRI examination. Results: Maximum patients belonged to age group 31-40 (30.5%. 32 (88.88% patients were males and 4 (11.11% were females. Bilateral AVN was detected in 44 (61.1% and unilateral in 14 patients (38.8%. Pre collapsed stage (Stages I and II was detected in 18 hips (31.03%, collapsed stage (Stages III and IV was detected in 40 hips (68.9%. Peripheral low-intensity rim was seen on T1WI in all 58 cases of AVN. Double line sign on T2-weighted image was seen in 33/58 (56.8%. Conclusion: Our study concluded that coronal T1W sequence is an easy, rapid and cost-effective method of detecting unilateral or bilateral AVN.

Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: mvmfonte@uol.com.br; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Radiologia; Reed, Umbertina Conti [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Rosemberg, Sergio [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Dept. de Patologia

2008-11-15

To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes; Reed, Umbertina Conti; Rosemberg, Sergio

2008-01-01

To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

Bone marrow oedema on MR imaging indicates ARCO stage 3 disease in patients with AVN of the femoral head

Energy Technology Data Exchange (ETDEWEB)

Meier, Reinhard; Schaeffeler, Christoph; Waldt, Simone; Rummeny, Ernst J.; Woertler, Klaus [Klinikum rechts der Isar, Technische Universitaet Muenchen, Department of Diagnostic and Interventional Radiology, Munich (Germany); Kraus, Tobias M. [Klinikum rechts der Isar, Technische Universitaet Muenchen, Department of Orthopaedics, Munich (Germany); Berufsgenossenschaftliche Unfallklinik Tuebingen, Department of Trauma and Orthopaedics, Tuebingen (Germany); Torka, Sebastian [Klinikum rechts der Isar, Technische Universitaet Muenchen, Department of Orthopaedics, Munich (Germany); Berufsgenossenschaftliche Unfallklinik Murnau, Department of Trauma and Orthopaedics, Murnau (Germany); Schlitter, Anna Melissa; Specht, Katja [Klinikum rechts der Isar, Technische Universitaet Muenchen, Institute of Pathology, Munich (Germany); Haller, Bernhard [Klinikum rechts der Isar, Technische Universitaet Muenchen, Institute of Medical Statistics and Epidemiology, Munich (Germany); Rechl, Hans [Klinikum rechts der Isar, Technische Universitaet Muenchen, Department of Orthopaedics, Munich (Germany)

2014-09-15

To test the hypothesis that bone marrow oedema (BME) observed on MRI in patients with avascular necrosis (AVN) of the femoral head represents an indicator of subchondral fracture. Thirty-seven symptomatic hips of 27 consecutive patients (53 % women, mean age 49.2) with AVN of the femoral head and associated BME on magnetic resonance (MR) imaging were included. MR findings were correlated with computed tomography (CT) of the hip and confirmed by histopathological examination of the resected femoral head. Imaging studies were analysed by two radiologists with use of the ARCO classification. On MR imaging a fracture line could be identified in 19/37 (51 %) cases, which were classified as ARCO stage 3 (n = 15) and stage 4 (n = 4). The remaining 18/37 (49 %) cases were classified as ARCO stage 2. However, in all 37/37 (100 %) cases a subchondral fracture was identified on CT, indicating ARCO stage 3/4 disease. The extent of subchondral fractures and the femoral head collapse was graded higher on CT as compared to MRI (P < 0.05). Histopathological analysis confirmed bone necrosis and subchondral fractures. In patients with AVN, BME of the femoral head represents a secondary sign of subchondral fracture and thus indicates ARCO stage 3 disease. circle BME on MRI in AVN of femoral head indicates a subchondral fracture. (orig.)

Bone marrow oedema on MR imaging indicates ARCO stage 3 disease in patients with AVN of the femoral head

International Nuclear Information System (INIS)

Meier, Reinhard; Schaeffeler, Christoph; Waldt, Simone; Rummeny, Ernst J.; Woertler, Klaus; Kraus, Tobias M.; Torka, Sebastian; Schlitter, Anna Melissa; Specht, Katja; Haller, Bernhard; Rechl, Hans

2014-01-01

To test the hypothesis that bone marrow oedema (BME) observed on MRI in patients with avascular necrosis (AVN) of the femoral head represents an indicator of subchondral fracture. Thirty-seven symptomatic hips of 27 consecutive patients (53 % women, mean age 49.2) with AVN of the femoral head and associated BME on magnetic resonance (MR) imaging were included. MR findings were correlated with computed tomography (CT) of the hip and confirmed by histopathological examination of the resected femoral head. Imaging studies were analysed by two radiologists with use of the ARCO classification. On MR imaging a fracture line could be identified in 19/37 (51 %) cases, which were classified as ARCO stage 3 (n = 15) and stage 4 (n = 4). The remaining 18/37 (49 %) cases were classified as ARCO stage 2. However, in all 37/37 (100 %) cases a subchondral fracture was identified on CT, indicating ARCO stage 3/4 disease. The extent of subchondral fractures and the femoral head collapse was graded higher on CT as compared to MRI (P < 0.05). Histopathological analysis confirmed bone necrosis and subchondral fractures. In patients with AVN, BME of the femoral head represents a secondary sign of subchondral fracture and thus indicates ARCO stage 3 disease. circle BME on MRI in AVN of femoral head indicates a subchondral fracture. (orig.)

Superresolution Imaging Using Resonant Multiples

KAUST Repository

Guo, Bowen

2017-12-22

A resonant multiple is defined as a multiple reflection that revisits the same subsurface location along coincident reflection raypaths. We show that resonant first-order multiples can be migrated with either Kirchhoff or wave-equation migration methods to give images with approximately twice the spatial resolution compared to post-stack primary-reflection images. A moveout-correction stacking method is proposed to enhance the signal-to-noise ratios (SNRs) of the resonant multiples before superresolution migration. The effectiveness of this procedure is validated by synthetic and field data tests.

Superresolution Imaging Using Resonant Multiples

KAUST Repository

Guo, Bowen; Schuster, Gerard T.

2017-01-01

A resonant multiple is defined as a multiple reflection that revisits the same subsurface location along coincident reflection raypaths. We show that resonant first-order multiples can be migrated with either Kirchhoff or wave-equation migration methods to give images with approximately twice the spatial resolution compared to post-stack primary-reflection images. A moveout-correction stacking method is proposed to enhance the signal-to-noise ratios (SNRs) of the resonant multiples before superresolution migration. The effectiveness of this procedure is validated by synthetic and field data tests.

Traumatic injuries: imaging of head injuries

Energy Technology Data Exchange (ETDEWEB)

Besenski, N. [Croatian Institute for Brain Research, Zagreb (Croatia)

2002-06-01

Due to the forces of acceleration, linear translation, as well as rotational and angular acceleration, the brain undergoes deformation and distortion depending on the site of impact of traumatizing force direction, severity of the traumatizing force, and tissue resistance of the brain. Linear translation of accereration in a closed-head injury can run along the shorter diameter of the skull in latero-lateral direction causing mostly extra-axial lesions (subdural hematoma,epidural hematoma, subarachnoidal hemorrhage) or quite pronounced coup and countercoup contusions. Contusions are considerably less frequently present in medial or paramedial centroaxial blows (fronto-occipital or occipito-frontal). The centroaxial blows produce a different pattern of lesions mostly in the deep structures, causing in some cases a special category of the brain injury, the diffuse axonal injury (DAI). The brain stem can also be damaged, but it is damaged more often in patients who have suffered centroaxial traumatic force direction. Computed tomography and MRI are the most common techniques in patients who have suffered brain injury. Computed tomography is currently the first imaging technique to be used after head injury, in those settings where CT is available. Using CT, scalp, bone, extra-axial hematomas, and parenchymal injury can be demonstrated. Computed tomography is rapid and easily performed also in monitored patients. It is the most relevant imaging procedure for surgical lesions. Computed tomography is a suitable method to follow the dynamics of lesion development giving an insight into the corresponding pathological development of the brain injury. Magnetic resonance imaging is more sensitive for all posttraumatic lesions except skull fractures and subarachnoidal hemorrhage, but scanning time is longer, and the problem with the monitoring of patients outside the MRI field is present. If CT does not demonstrate pathology as can adequately be explained to account for

Traumatic injuries: imaging of head injuries

International Nuclear Information System (INIS)

Besenski, N.

2002-01-01

Due to the forces of acceleration, linear translation, as well as rotational and angular acceleration, the brain undergoes deformation and distortion depending on the site of impact of traumatizing force direction, severity of the traumatizing force, and tissue resistance of the brain. Linear translation of accereration in a closed-head injury can run along the shorter diameter of the skull in latero-lateral direction causing mostly extra-axial lesions (subdural hematoma,epidural hematoma, subarachnoidal hemorrhage) or quite pronounced coup and countercoup contusions. Contusions are considerably less frequently present in medial or paramedial centroaxial blows (fronto-occipital or occipito-frontal). The centroaxial blows produce a different pattern of lesions mostly in the deep structures, causing in some cases a special category of the brain injury, the diffuse axonal injury (DAI). The brain stem can also be damaged, but it is damaged more often in patients who have suffered centroaxial traumatic force direction. Computed tomography and MRI are the most common techniques in patients who have suffered brain injury. Computed tomography is currently the first imaging technique to be used after head injury, in those settings where CT is available. Using CT, scalp, bone, extra-axial hematomas, and parenchymal injury can be demonstrated. Computed tomography is rapid and easily performed also in monitored patients. It is the most relevant imaging procedure for surgical lesions. Computed tomography is a suitable method to follow the dynamics of lesion development giving an insight into the corresponding pathological development of the brain injury. Magnetic resonance imaging is more sensitive for all posttraumatic lesions except skull fractures and subarachnoidal hemorrhage, but scanning time is longer, and the problem with the monitoring of patients outside the MRI field is present. If CT does not demonstrate pathology as can adequately be explained to account for

Artifacts by dental materials on magnetic resonance imaging

International Nuclear Information System (INIS)

Hong, Hyun Sook; Choi, Deuk Lin; Kim, Ki Jung; Suh, Won Hyuck

1992-01-01

Magnetic resonance imaging (MRI) has proved to be a valuable method for evaluation of the head and neck. Unfortunately, metallic devices associated with certain dental fillings and appliances often cause variable artifacts that can obscure normal or pathologic conditions on MR and computed tomography. In this work, we assessed the MR appearance of dental prosthetic materials in vitro and in vivo including precious alloys, nonprecions alloys, resin, amalgam and titanium alloy. For in vivo studies, these materials were placed in healthy volunteer's mouths and then images were assessed. Analysis of the appearance of shape and extent of artifact, and observed influence of these artifacts on the image interpretation at 0.2 Tesla permanent type MR scanner were valuated. Material used as temporary or permanent filling of crowns such as amalgam, precious alloy and, microfilled resin did not cause artifact on the image. The size of the artifact produced by the nonprecious alloys was influenced by the ferromagnetism of the object and the volume prosthesis, and was related to the scanning sequence. Nonprecious alloys produced minimal local signal distortion, where precious alloys, and dental resin had no effect on the MR images in vivo. These results were mainly from a low field strength MR scanner used in this study

Slotted cage resonator for high-field magnetic resonance imaging of rodents

Energy Technology Data Exchange (ETDEWEB)

Marrufo, O; Vasquez, F; Solis, S E; Rodriguez, A O, E-mail: arog@xanum.uam.mx [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico)

2011-04-20

A variation of the high-frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. Circular slots were used instead of cavities to form the coil endplates and it was called the slotted cage resonator coil. The theoretical principles were validated via a coil equivalent circuit and also experimentally with a coil prototype. The radio frequency magnetic field, B1, produced by several coil configurations was numerically simulated using the finite-element approach to investigate their performances. A transceiver coil, 8 cm long and 7.6 cm in diameter, and composed of 4 circular slots with a 15 mm diameter on both endplates, was built to operate at 300 MHz and quadrature driven. Experimental results obtained with the slotted cage resonator coil were presented and showed very good agreement with the theoretical expectations for the resonant frequency as a function of the coil dimensions and slots. A standard birdcage coil was also built for performance comparison purposes. Phantom images were then acquired to compute the signal-to-noise ratio of both coils showing an important improvement of the slotted cage coil over the birdcage coil. The whole-body images of the mouse were also obtained showing high-quality images. Volume resonator coils can be reliably built following the physical principles of the cavity resonator design for high-field magnetic resonance imaging applications of rodents.

MIDA: A Multimodal Imaging-Based Detailed Anatomical Model of the Human Head and Neck.

Directory of Open Access Journals (Sweden)

Maria Ida Iacono

Full Text Available Computational modeling and simulations are increasingly being used to complement experimental testing for analysis of safety and efficacy of medical devices. Multiple voxel- and surface-based whole- and partial-body models have been proposed in the literature, typically with spatial resolution in the range of 1-2 mm and with 10-50 different tissue types resolved. We have developed a multimodal imaging-based detailed anatomical model of the human head and neck, named "MIDA". The model was obtained by integrating three different magnetic resonance imaging (MRI modalities, the parameters of which were tailored to enhance the signals of specific tissues: i structural T1- and T2-weighted MRIs; a specific heavily T2-weighted MRI slab with high nerve contrast optimized to enhance the structures of the ear and eye; ii magnetic resonance angiography (MRA data to image the vasculature, and iii diffusion tensor imaging (DTI to obtain information on anisotropy and fiber orientation. The unique multimodal high-resolution approach allowed resolving 153 structures, including several distinct muscles, bones and skull layers, arteries and veins, nerves, as well as salivary glands. The model offers also a detailed characterization of eyes, ears, and deep brain structures. A special automatic atlas-based segmentation procedure was adopted to include a detailed map of the nuclei of the thalamus and midbrain into the head model. The suitability of the model to simulations involving different numerical methods, discretization approaches, as well as DTI-based tensorial electrical conductivity, was examined in a case-study, in which the electric field was generated by transcranial alternating current stimulation. The voxel- and the surface-based versions of the models are freely available to the scientific community.

MRI in head trauma

International Nuclear Information System (INIS)

Hong, Jin Kyo

1986-01-01

In the diagnosis of head injury, Magnetic Resonance Imaging (MRI), like CT, is an effective method of distinguishing between intracerebral and extracerebral lesions. In our experience of MRI, early hematomas are almost isointense by Saturation Recovery (SR) method, so these must be performed with Spin Echo (SE) method for better visualization of hematomas. Isodense subdural hematomas, which is a diagnostic dilemma on CT images, are clearly seen on MRI. Delayed hematomas or residual parenchymal lesions are better demonstrated on MRI than on CT. Direct cornal, sagittal images and multiplanar facility of MRI provides excellent visualization of the the location and shape of extracerebral collection of hematoma. For the screening of head traumas, SE method is a technique of choice because of its excellent sensitivity within limited time.

MRI in head trauma

Energy Technology Data Exchange (ETDEWEB)

Hong, Jin Kyo [Shin Wha Hospital, Seoul (Korea, Republic of)

1986-02-15

In the diagnosis of head injury, Magnetic Resonance Imaging (MRI), like CT, is an effective method of distinguishing between intracerebral and extracerebral lesions. In our experience of MRI, early hematomas are almost isointense by Saturation Recovery (SR) method, so these must be performed with Spin Echo (SE) method for better visualization of hematomas. Isodense subdural hematomas, which is a diagnostic dilemma on CT images, are clearly seen on MRI. Delayed hematomas or residual parenchymal lesions are better demonstrated on MRI than on CT. Direct cornal, sagittal images and multiplanar facility of MRI provides excellent visualization of the the location and shape of extracerebral collection of hematoma. For the screening of head traumas, SE method is a technique of choice because of its excellent sensitivity within limited time.

Visualization of isolated trigeminal nerve invasion by lymphoma using gadolinium-enhanced magnetic resonance imaging

International Nuclear Information System (INIS)

Manon-Espaillat, R.; Lanska, D.J.; Ruff, R.L.; Cleveland Veteran's Administration Medical Center, OH; Case Western Reserve Univ., Cleveland, OH; Masaryk, T.; University Hospitals of Cleveland, OH; Case Western Reserve Univ., Cleveland, OH

1990-01-01

A 50-year-old man with active histiocytic lymphoma for 12 years developed an isolated right trigeminal neuropathy. Initial evaluation with head computed tomography, X-rays of the skull base, bone scan, and cerebrospinal fluid analysis including cytology were normal. Gadolinium-enhanced magnetic resonance imaging (MRI) showed enlargement of the proximal third of the right trigeminal nerve. Gadolinium-enhanced MRI can be useful for the early demonstration of cranial nerve invasion by lymphoma. (orig.)

Magnetic resonance imaging of the fetal brain.

Science.gov (United States)

Tee, L Mf; Kan, E Yl; Cheung, J Cy; Leung, W C

2016-06-01

This review covers the recent literature on fetal brain magnetic resonance imaging, with emphasis on techniques, advances, common indications, and safety. We conducted a search of MEDLINE for articles published after 2010. The search terms used were "(fetal OR foetal OR fetus OR foetus) AND (MR OR MRI OR [magnetic resonance]) AND (brain OR cerebral)". Consensus statements from major authorities were also included. As a result, 44 relevant articles were included and formed the basis of this review. One major challenge is fetal motion that is largely overcome by ultra-fast sequences. Currently, single-shot fast spin-echo T2-weighted imaging remains the mainstay for motion resistance and anatomical delineation. Recently, a snap-shot inversion recovery sequence has enabled robust T1-weighted images to be obtained, which is previously a challenge for standard gradient-echo acquisitions. Fetal diffusion-weighted imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also being developed. With multiplanar capabilities, superior contrast resolution and field of view, magnetic resonance imaging does not have the limitations of sonography, and can provide additional important information. Common indications include ventriculomegaly, callosum and posterior fossa abnormalities, and twin complications. There are safety concerns about magnetic resonance-induced heating and acoustic damage but current literature showed no conclusive evidence of deleterious fetal effects. The American College of Radiology guideline states that pregnant patients can be accepted to undergo magnetic resonance imaging at any stage of pregnancy if risk-benefit ratio to patients warrants that the study be performed. Magnetic resonance imaging of the fetal brain is a safe and powerful adjunct to sonography in prenatal diagnosis. It can provide additional information that aids clinical management, prognostication, and counselling.

A comparison of clinical symptoms and magnetic resonance images in temporomandibular joint disorders

Energy Technology Data Exchange (ETDEWEB)

Choi, Yong Suk; Hwang, Eui Hwan; Lee, Sang Rae [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

2003-06-15

To determine the relationship between clinical symptoms and magnetic resonance (MR) images in patients presenting with temporomandibular joint (TMJ) disorders. This study was based on 172 joints in 86 patients presenting with TMJ disorders. Joint pain and sound during jaw opening and closing movements were recorded, and the possible relationship between disc positions and bony changes of the condylar head and the articular fossa in MR images in the oblique sagittal planes were examined. Data were analyzed by Chi-square test. There was no statistically significant relationship between clinical symptoms and MR images in the patients with TMJ disorders. In the patient with TMJ disorders, joint pain and sound could not be specific clinical symptoms that are related with MR image findings, and asymptomatic joint did not necessarily imply that the joints are normal according to MR image findings.

Transmission imaging for registration of ictal and interictal single-photon emission tomography, magnetic resonance imaging and electroencephalography

Energy Technology Data Exchange (ETDEWEB)

Sipilae, O. [Epilepsy Unit, Neurology, Hospital for Children and Adolescents, Helsinki University Central Hospital (Finland); Laboratory of Biomedical Engineering, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT (Finland); Nikkinen, P.; Liewendahl, K. [Division of Nuclear Medicine, Laboratory Department, Helsinki University Central Hospital (Finland); Savolainen, S. [Division of Nuclear Medicine, Laboratory Department, Helsinki University Central Hospital (Finland); Department of Radiology, Helsinki University Central Hospital (Finland); Granstroem, M.-L.; Gaily, E. [Epilepsy Unit, Neurology, Hospital for Children and Adolescents, Helsinki University Central Hospital (Finland); Poutanen, V.-P. [Department of Radiology, Helsinki University Central Hospital (Finland); Pohjonen, H. [Technology Development Centre, P.O. Box 69, 00101 Helsinki (Finland)

2000-02-01

A method developed for registration of ictal and interictal single-photon emission tomography (SPET), magnetic resonance imaging (MRI) and electroencephalography (EEG) is described. For SPET studies, technetium-99m ethyl cysteinate dimer (ECD) was injected intravenously while the patient was monitored on video-EEG to document the ictal or interictal state. Imaging was performed using a triple-head gamma camera equipped with a transmission imaging device using a gadolinium-153 source. The images (128 x 128 pixels, voxel size 3.7 x 3.7 x 3.6 mm{sup 3}) were reconstructed using an iterative algorithm and postfiltered with a Wiener filter. The gold-plated silver electrodes on the patient's scalp were utilized as markers for registration of the ictal and interictal SPET images, as these metallic markers were clearly seen on the transmission images. Fitting of the marker sets was based on a non-iterative least squares method. The interictal SPET image was subtracted from the ictal image after scaling. The T1-weighted MPRAGE MR images with voxel size of 1.0 x 1.0 x 1.0 mm{sup 3} were obtained with a 1.5-T scanner. For registration of MR and subtraction SPET images, the external marker set of the ictal SPET study was fitted to the surface of the head segmented from MR images. The SPET registration was tested with a phantom experiment. Registration of ictal and interictal SPET in five patient studies resulted in a 2-mm RMS residual of the marker sets. The estimated RMS error of registration in the final result combining locations of the electrodes, subtraction SPET and MR images was 3-5 mm. In conclusion, transmission imaging can be utilized for an accurate and easily implemented registration procedure for ictal and interictal SPET, MRI and EEG. (orig.)

Magnetic Resonance Imaging (MRI): Brain (For Parents)

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Brain KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Brain What's in this article? What ...

Magnetic resonance imaging (MRI)

OpenAIRE

Takavar A

1993-01-01

Basic physical principles of nuclear magnetic resonance imaging (N.M.R.I), a nonionizing medical imaging technique, are described. Principles of NMRI with other conventional imaging methods, ie, isotope scanning, ultrasonography and radiography have been compared. T1 and T2 and spin density (S.D.) factors and different image construction techniques based on their different combinations is discussed and at the end physical properties of some N.M.R images is mentioned.

Magnetic resonance imaging of the elbow. Part I: Normal anatomy, imaging technique, and osseous abnormalities

International Nuclear Information System (INIS)

Kijowski, Richard; Tuite, Michael; Sanford, Matthew

2004-01-01

Part I of this comprehensive review on magnetic resonance imaging of the elbow discusses normal elbow anatomy and the technical factors involved in obtaining high-quality magnetic resonance images of the elbow. Part I also discusses the role of magnetic resonance imaging in evaluating patients with osseous abnormalities of the elbow. With proper patient positioning and imaging technique, magnetic resonance imaging can yield high-quality multiplanar images which are useful in evaluating the osseous structures of the elbow. Magnetic resonance imaging can detect early osteochondritis dissecans of the capitellum and can be used to evaluate the size, location, stability, and viability of the osteochondritis dissecans fragment. Magnetic resonance imaging can detect early stress injury to the proximal ulna in athletes. Magnetic resonance imaging can detect radiographically occult fractures of the elbow in both children and adults. Magnetic resonance imaging is also useful in children to further evaluate elbow fractures which are detected on plain-film radiographs. (orig.)

Head and Neck Veins of the Mouse. A Magnetic Resonance, Micro Computed Tomography and High Frequency Color Doppler Ultrasound Study.

Directory of Open Access Journals (Sweden)

Marcello Mancini

Full Text Available To characterize the anatomy of the venous outflow of the mouse brain using different imaging techniques. Ten C57/black male mice (age range: 7-8 weeks were imaged with high-frequency Ultrasound, Magnetic Resonance Angiography and ex-vivo Microcomputed tomography of the head and neck. Under general anesthesia, Ultrasound of neck veins was performed with a 20 MHz transducer; head and neck Magnetic Resonance Angiography data were collected on 9.4 T or 7 T scanners, and ex-vivo Microcomputed tomography angiography was obtained by filling the vessels with a radiopaque inert silicone rubber compound. All procedures were approved by the local ethical committee. The dorsal intracranial venous system is quite similar in mice and humans. Instead, the mouse Internal Jugular Veins are tiny vessels receiving the sigmoid sinuses and tributaries from cerebellum, occipital lobe and midbrain, while the majority of the cerebral blood, i.e. from the olfactory bulbs and fronto-parietal lobes, is apparently drained through skull base connections into the External Jugular Vein. Three main intra-extracranial anastomoses, absent in humans, are: 1 the petrosquamous sinus, draining into the posterior facial vein, 2 the veins of the olfactory bulb, draining into the superficial temporal vein through a foramen of the frontal bone 3 the cavernous sinus, draining in the External Jugular Vein through a foramen of the sphenoid bone. The anatomical structure of the mouse cranial venous outflow as depicted by Ultrasound, Microcomputed tomography and Magnetic Resonance Angiography is different from humans, with multiple connections between intra- and extra-cranial veins.

Functional magnetic resonance imaging by visual stimulation

International Nuclear Information System (INIS)

Nishimura, Yukiko; Negoro, Kiyoshi; Morimatsu, Mitsunori; Hashida, Masahiro

1996-01-01

We evaluated functional magnetic resonance images obtained in 8 healthy subjects in response to visual stimulation using a conventional clinical magnetic resonance imaging system with multi-slice spin-echo echo planar imaging. Activation in the visual cortex was clearly demonstrated by the multi-slice experiment with a task-related change in signal intensity. In addition to the primary visual cortex, other areas were also activated by a complicated visual task. Multi-slice spin-echo echo planar imaging offers high temporal resolution and allows the three-dimensional analysis of brain function. Functional magnetic resonance imaging provides a useful noninvasive method of mapping brain function. (author)

Degeneration of pyramidal tract of MRI (magnetic resonance imaging)

International Nuclear Information System (INIS)

Yamagami, Tatsuhito; Harada, Noboru; Gotoh, Yasunobu; Imataka, Kiyoharu; Kinuta, Yuji; Okumura, Teizo; Niijima, Kyo; Taki, Waro; Kikuchi, Haruhiko.

1988-01-01

MRI (magnetic resonance imaging) examinaion was performed on cases of hemiplegia and hemiparesis. These included seven cases of intracerebral hemorrhage, four cases of subarachnoid hemorrhage, one case of cerebral infarct, and two cases of head trauma. The pyramidal tract in the brain stem was studied in five patients with complete hemiplegia and in nine with incomplete hemiparesis. The scanner of the MRI was a resistive type operating at a field of 0.2 Tesla. The inversion recovery (IR) and saturation recovery (SR) techniques were utilized. The pyramidal tract at the level of the midbrain and the pons was recognized as a low intensity area on the T 1 image (IR 1500/43) in the cases of complete hemiplegia. However, it was recognized as a high intensity area on the SR image (SR 1000/60) and the T 2 image (SR 2000/100). No abnormal signal intensity was found in the cases of incomplete hemiparesis. A low intensity area on the T 1 image and a high intensity area on the T 2 image were recognized in the ventral portion of the midbrain and the pons on the affected side. These findings indicate a degeneration of the pyramidal tract at the level of the brain stem in patients with complete hemiplegia. (author)

Magnetic resonance imaging in clinically-definite multiple sclerosis

International Nuclear Information System (INIS)

Noakes, J.B.; Herkes, G.K.; Frith, J.A.

1990-01-01

Forty-two patients with clinically-definite multiple sclerosis were examined by magnetic resonance imaging using a 1.5-T instrument. Magnetic resonance imaging detected an abnormality in 90% of patients. In four patients, no lesions were demonstrated. The number, size and site of the lesions by magnetic resonance imaging were compared with the patients' clinical status and other variables. The Kurtzke disability status scale score increased in patients with corpus callosum atrophy, brainstem and basal ganglia lesions, and correlated with the total number of lesions. No correlation was shown between the findings of magnetic resonance imaging and disease duration, age, sex or pattern-reversal visual-evoked potentials. The variety of magnetic resonance images that could be obtained in patients with clinically-definite multiple sclerosis is highlighted. 24 refs., 8 figs., 1 tab

Magnetic resonance imaging

International Nuclear Information System (INIS)

Sigal, R.

1988-01-01

This book is an introduction to magnetic resonance imaging (MRI). The basic principles for the interpretation of MR images are developed. The book is divided into five chapters: introduction, tissue, parameters, acquisition parameters, contribution to diagnosis, and practical management of an MR examination. Eight exercises allow the reader to test the knowledge he has acquired. Signal localization and MR artefacts are reviewed in an appendix

Magnetic resonance imaging of abnormal shoulder pain following influenza vaccination

Energy Technology Data Exchange (ETDEWEB)

Okur, Gokcan [Etimesgut Military Hospital, Department of Radiology, Ankara (Turkey); Chaney, Kimberly A. [Presence St. Joseph Hospital, Department of Radiology, Elgin, IL (United States); Lomasney, Laurie M. [Loyola University Medical Center, Department of Radiology, Maywood, IL (United States)

2014-09-15

The influenza vaccine is increasingly available to the general public and mandated by many employers in the United States. The prevalence of post-vaccination complications is likely on the rise. Complications are well known to general clinicians, but are under-reported in the imaging literature. We present four cases of post-vaccination shoulder pain with magnetic resonance imaging (MRI) findings. An intrasubstance fluid-like signal in deep muscular and/or tendinous structures was the most common finding on MRI of these four cases. Focal bone marrow signal within the humeral head and inflammatory changes in the subacromial/subdeltoid bursa were also observed. The most likely reason for a humeral intraosseous edema-like signal was presumed injection of vaccine substance directly into osseous structures that might lead to focal osteitis. In the published literature, there is little emphasis on the imaging of local injection site complications accompanying influenza vaccination. We intended to increase familiarity of MRI findings in the setting of prolonged or severe clinical symptoms following influenza vaccination through the imaging findings of these four cases. (orig.)

Magnetic resonance imaging of abnormal shoulder pain following influenza vaccination

International Nuclear Information System (INIS)

Okur, Gokcan; Chaney, Kimberly A.; Lomasney, Laurie M.

2014-01-01

The influenza vaccine is increasingly available to the general public and mandated by many employers in the United States. The prevalence of post-vaccination complications is likely on the rise. Complications are well known to general clinicians, but are under-reported in the imaging literature. We present four cases of post-vaccination shoulder pain with magnetic resonance imaging (MRI) findings. An intrasubstance fluid-like signal in deep muscular and/or tendinous structures was the most common finding on MRI of these four cases. Focal bone marrow signal within the humeral head and inflammatory changes in the subacromial/subdeltoid bursa were also observed. The most likely reason for a humeral intraosseous edema-like signal was presumed injection of vaccine substance directly into osseous structures that might lead to focal osteitis. In the published literature, there is little emphasis on the imaging of local injection site complications accompanying influenza vaccination. We intended to increase familiarity of MRI findings in the setting of prolonged or severe clinical symptoms following influenza vaccination through the imaging findings of these four cases. (orig.)

Magnetic resonance imaging in the diagnosis of pancreatic diseases

International Nuclear Information System (INIS)

Yamaguchi, Taketo; Ebara, Masaaki; Saisho, Hiromitsu

1987-01-01

Fifty patients with various pancreatic diseases and 22 without pancreatic disease were studied by a magnetic resonance imaging (MRI) to compare its diagnostic capability with that by an X-ray CT scan. To differentiate pancreas clearly from the bowel, an iron solution was orally administered as contrast medium, resulting in a usefullness, especially to differentiate the head of the pancreas from the bowel. The head of the pancreas could be identified in 89 % after iron solution but only in 62 % without it. MRI was inferior to CT in terms of visualization of the pancreatic duct and pancreatic stones, but was superior in a visualization of vessels around the pancreas. MRI was considered to be useful for a detection of carcinoma infiltrating to vessels. Pancreatic carcinoma was differentiated from chronic pancreatitis in terms of a local enlargement and disappearance of fat around the pancreas shown on MRI findings. The present results also showed statistically significant differences in T 1 relaxation times among normal pancreas, chronic pancreatitis and pancreatic carcinoma, suggesting a useful marker in the differential diagnosis of pancreatic diseases. (author)

Magnetic resonance imaging (MRI

Directory of Open Access Journals (Sweden)

Takavar A

1993-04-01

Full Text Available Basic physical principles of nuclear magnetic resonance imaging (N.M.R.I, a nonionizing medical imaging technique, are described. Principles of NMRI with other conventional imaging methods, ie, isotope scanning, ultrasonography and radiography have been compared. T1 and T2 and spin density (S.D. factors and different image construction techniques based on their different combinations is discussed and at the end physical properties of some N.M.R images is mentioned.

Correlation of cumulative corticosteroid treatment with magnetic resonance imaging assessment of avascular femoral head necrosis in patients with multiple sclerosis

Directory of Open Access Journals (Sweden)

Nilufer Kale

2010-10-01

Full Text Available Increased risk of osteoporosis, fractures, and avascular necrosis (AVN has been suggested in multiple sclerosis (MS. Patients with MS are often exposed to corticosteroid treatment (CST during the disease course and conflicting reports exist regarding complications of CST. Our study aims to investigate the association between cumulative doses of CST and radiographic evaluation of AVN of the femoral head in MS. Twenty-six MS patients (mean age, 38.4±10 yr were enrolled and prospectively evaluated for AVN by magnetic resonance imaging (MRI. The mean disease duration was 11.5±8.5 years and mean expanded disability status scale (EDSS score was 3±2. The cumulative dosage of CST varied between 20 g and 60 g; patients were grouped into two categories: 1 CST between 20-40 g, 17 (65% patients; 2 CST ≥40 g; 9 (35% patients. The relationship between cumulative CST dosage and MRI diagnosis of AVN was stat­istically insignificant (P>0.9. Clarification of the cumulative effect of CST in the development of AVN is of great importance for future long-term steroid treatment strategies.

A new 3-dimensional head fixation device for brain imaging

International Nuclear Information System (INIS)

Goto, Ryoi; Kawashima, Ryuta; Yoshioka, Seiro; Ono, Shuichi; Ito, Hiroshi; Sato, Kazunori; Akaizawa, Takashi; Koyama, Masamichi; Fukuda, Hiroshi

1995-01-01

We have developed a new head fixation device for studies of brain function. This device was designed to immobilize subject's heads during image scanning and to precisely reproduce the head position for two different imaging modalities such as MRI and PET. The device consists of a plastic frame, a pillow filled with beads of styrene foam, and a face mask of thermoplastic resin which was originally intended for application in radiotherapy. A bridge for biting was incorporated into the mask for stable fixation. The device enables immobilization of subject's heads with good reproducibility of position at the practical level. Our results indicate that this head fixation system is useful for fixation of head during activation studies using PET. (author)

Imaging of juvenile spondyloarthritis. Part II: Ultrasonography and magnetic resonance imaging

Directory of Open Access Journals (Sweden)

Iwona Sudoł-Szopińska

2017-09-01

Full Text Available Juvenile spondyloarthropathies are mainly manifested by symptoms of peripheral arthritis and enthesitis. Early involvement of sacroiliac joints and spine is exceptionally rare in children; this usually happens in adulthood. Conventional radiographs visualize late inflammatory lesions. Early diagnosis is possible with the use of ultrasonography and magnetic resonance imaging. The first part of the article presented classifications and radiographic presentation of juvenile spondyloarthropathies. This part discusses changes seen on ultrasonography and magnetic resonance imaging. In patients with juvenile spondyloarthropathies, these examinations are conducted to diagnose inflammatory lesions in peripheral joints, tendon sheaths, tendons and bursae. Moreover, magnetic resonance also shows subchondral bone marrow edema, which is considered an early sign of inflammation. Ultrasonography and magnetic resonance imaging do not show specific lesions for any rheumatic disease. Nevertheless, they are conducted for early diagnosis, treatment monitoring and identifying complications. This article presents a spectrum of inflammatory changes and discusses the diagnostic value of ultrasonography and magnetic resonance imaging.

Functional Magnetic Resonance Imaging

Science.gov (United States)

Voos, Avery; Pelphrey, Kevin

2013-01-01

Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

Magnetic resonance imaging in children with acute hip pain

Energy Technology Data Exchange (ETDEWEB)

Ranner, G.; Ebner, F.; Fotter, R.; Justich, E. (Graz Univ. (Austria). Radiologische Klinik); Linhart, W. (Graz Univ. (Austria). Kinderklinik)

1989-11-01

45 children presenting with acute hip pain were prospectively evaluated with conventional radiography, radioisotope bone scan, and magnetic resonance imaging (MRI). The final diagnoses were transient synovitis (n=17), septic arthritis (n=2), Legg-Calve-Perthes disease (LCPD, n=13), epiphyseal dysplasia (n=2), other conditions (n=4), and normal findings (n=7). In the work-up MRI provided more morphologic information than other techniques and enlarged the diagnostic possibilities. It was the only imaging technique able to give an early indication of bone marrow involvement in systemic diseases. For the early diagnosis of LCPD, MRI was as sensitive as isotope bone scan and more precise than conventional radiography. In the follow-up of LCPD patients MRI was not able to indicate the start of revascularisation of the necrotic area, which bone scans showed reliably in six patients: But MRI provided excellent evaluation of the position, form and size of the femoral head and the surrounding soft tissues. (orig.).

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... work? Unlike conventional x-ray examinations and computed tomography (CT) scans, MRI does not utilize ionizing radiation. Instead, ... Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's (Pediatric) CT (Computed Tomography) Magnetic Resonance Imaging (MRI) Safety Contrast Materials Children ...

SAR in human head model due to resonant wireless power transfer system.

Science.gov (United States)

Zhang, Chao; Liu, Guoqiang; Li, Yanhong; Song, Xianjin

2016-04-29

Efficient mid-range wireless power transfer between transmitter and the receiver has been achieved based on the magnetic resonant coupling method. The influence of electromagnetic field on the human body due to resonant wireless power transfer system (RWPT) should be taken into account during the design process of the system. To analyze the transfer performance of the RWPT system and the change rules of the specific absorption rate (SAR) in the human head model due to the RWPT system. The circuit-field coupling method for a RWPT system with consideration of the displacement current was presented. The relationship between the spiral coil parameters and transfer performance was studied. The SAR in the human head model was calculated under two different exposure conditions. A system with output power higher than 10 W at 0.2 m distance operating at a frequency of approximately 1 MHz was designed. The FEM simulation results show the peak SAR value is below the safety limit which appeared when the human head model is in front of the transmitter. The simulation results agreed well with the experimental results, which verified the validity of the analysis and design.

76 FR 58281 - Magnetic Resonance Imaging Safety; Public Workshop

Science.gov (United States)

2011-09-20

...] Magnetic Resonance Imaging Safety; Public Workshop AGENCY: Food and Drug Administration, HHS. ACTION... announcing a public workshop entitled: ``Magnetic Resonance Imaging (MRI) Safety Public Workshop.'' The purpose of the public workshop is to discuss factors affecting the safe use of magnetic resonance imaging...

Functional magnetic resonance imaging of the primary motor cortex ...

Indian Academy of Sciences (India)

Unknown

Abbreviations used: BOLD, Blood oxygenation level dependent; CBF, cerebral blood flow; fMRI, functional magnetic resonance imaging; EPI, eco-planar imaging; FOV, field of view; MRI, Magnetic resonance imaging; MRS, magnetic resonance spectroscopy;. PET, position emission tomography; rCBF, regional cerebral ...

Educational paper Abusive Head Trauma Part II: Radiological aspects

NARCIS (Netherlands)

Sieswerda-Hoogendoorn, Tessa; Boos, Stephen; Spivack, Betty; Bilo, Rob A. C.; van Rijn, Rick R.

2012-01-01

Abusive head trauma (AHT) is a relatively common cause of neurotrauma in young children. Radiology plays an important role in establishing a diagnosis and assessing a prognosis. Computed tomography (CT), followed by magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI), is the

Magnetic resonance imaging of infectious myositis

Energy Technology Data Exchange (ETDEWEB)

Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha [The Catholic Univ., College of Medicine, Suwon (Korea, Republic of)

1998-09-01

To describe the findings of magnetic resonance imaging in infectious myositis and to determine their value for differentiation between ruberculous and bacterial myositis. Magnetic resonance images of ten proven cases of infectious myositis (five tuberculous and five bacterial) were retrospectively reviewed in the light of clinical and laboratory findings. On the basis of magnetic resonance images, signal intensity of the mass, the presence or absence of an abscess, signal intensity of the peripheral wall, patterns of contrast enhancement, and associated findings were evaluated. Compared with those of bacterial myositis, the symptoms of tuberculous myositis lasted longer but there were no difinite local inflammatory signs. In three of five cases of bacterial myositis there were specific medical records;trauma in two cases and systemic lupus erythematosus in one. All tuberculous myositis cases involved a single muscle, but bacterial myositis affected multipe muscles in three cases(60%). All but one case showed a mass in the involved muscles. In one bacterial case, there was diffuse swelling in the involved muscle. On T1-weighted images, eight infectious cases showed low signal intensity;two, of the bactrerial type, showed subtle increased signal intensity. all cases demonstrated high signal intensity on t2-weighted images. The signal intensity of peripheral wall was slightly increased on T1-weighted images, but low on T2-weighted. In four cases there was associated cellulitis, and in one case each, adjacent joint effusion and deep vein thrombosis were seen. After gadolinium infusion, peripheral rim enhancement was noted in nine cases and heterogeneous enhancement in one. After magnetic resonance imaging of infectious myositis, the characteristic finding was an abscessed lesion, with the peripheral wall showing high signal intensity on T1-weighted images and low signal intensity on T2 weighted. Although we found it difficult to differentiate bacterial from tuberculous

Magnetic resonance imaging of infectious myositis

International Nuclear Information System (INIS)

Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha

1998-01-01

To describe the findings of magnetic resonance imaging in infectious myositis and to determine their value for differentiation between ruberculous and bacterial myositis. Magnetic resonance images of ten proven cases of infectious myositis (five tuberculous and five bacterial) were retrospectively reviewed in the light of clinical and laboratory findings. On the basis of magnetic resonance images, signal intensity of the mass, the presence or absence of an abscess, signal intensity of the peripheral wall, patterns of contrast enhancement, and associated findings were evaluated. Compared with those of bacterial myositis, the symptoms of tuberculous myositis lasted longer but there were no difinite local inflammatory signs. In three of five cases of bacterial myositis there were specific medical records;trauma in two cases and systemic lupus erythematosus in one. All tuberculous myositis cases involved a single muscle, but bacterial myositis affected multipe muscles in three cases(60%). All but one case showed a mass in the involved muscles. In one bacterial case, there was diffuse swelling in the involved muscle. On T1-weighted images, eight infectious cases showed low signal intensity;two, of the bactrerial type, showed subtle increased signal intensity. all cases demonstrated high signal intensity on t2-weighted images. The signal intensity of peripheral wall was slightly increased on T1-weighted images, but low on T2-weighted. In four cases there was associated cellulitis, and in one case each, adjacent joint effusion and deep vein thrombosis were seen. After gadolinium infusion, peripheral rim enhancement was noted in nine cases and heterogeneous enhancement in one. After magnetic resonance imaging of infectious myositis, the characteristic finding was an abscessed lesion, with the peripheral wall showing high signal intensity on T1-weighted images and low signal intensity on T2 weighted. Although we found it difficult to differentiate bacterial from tuberculous

Musculoskeletal applications of magnetic resonance imaging: Council on Scientific Affairs

International Nuclear Information System (INIS)

Harms, S.E.; Fisher, C.F.; Fulmer, J.M.

1989-01-01

Magnetic resonance imaging provides superior contrast, resolution, and multiplanar imaging capability, allowing excellent definition of soft-tissue and bone marrow abnormalities. For these reasons, magnetic resonance imaging has become a major diagnostic imaging method for the evaluation of many musculoskeletal disorders. The applications of magnetic resonance imaging for musculoskeletal diagnosis are summarized and examples of common clinical situations are given. General guidelines are suggested for the musculoskeletal applications of magnetic resonance imaging

Imaging by magnetic resonance

International Nuclear Information System (INIS)

Duroure, J.F.; Serpolay, H.; Vallens, D.

1995-01-01

Here are described the advanced technology for nuclear magnetic resonance imaging: reduction of acquisition times, and rebuilding times, images quality improvement. The tendency is to open the machines at low and middle field, on a market being at 10% of NMR I sales, with economical, scientifical and ergonomic reasons broadly developed by constructors

Brain redox imaging in the pentylenetetrazole (PTZ)-induced kindling model of epilepsy by using in vivo electron paramagnetic resonance and a nitroxide imaging probe.

Science.gov (United States)

Emoto, Miho C; Yamato, Mayumi; Sato-Akaba, Hideo; Yamada, Ken-ichi; Fujii, Hirotada G

2015-11-03

Much evidence supports the idea that oxidative stress is involved in the pathogenesis of epilepsy, and therapeutic interventions with antioxidants are expected as adjunct antiepileptic therapy. The aims of this study were to non-invasively obtain spatially resolved redox data from control and pentylenetetrazole (PTZ)-induced kindled mouse brains by electron paramagnetic resonance (EPR) imaging and to visualize the brain regions that are sensitive to oxidative damage. After infusion of the redox-sensitive imaging probe 3-methoxycarbonyl-2,2,5,5-tetramethyl-piperidine-1-oxyl (MCP), a series of EPR images of PTZ-induced mouse heads were measured. Based on the pharmacokinetics of the reduction reaction of MCP in the mouse heads, the pixel-based rate constant of its reduction reaction was calculated as an index of redox status in vivo and mapped as a redox map. The obtained redox map showed heterogeneity in the redox status in PTZ-induced mouse brains compared with control. The co-registered image of the redox map and magnetic resonance imaging (MRI) for both control and PTZ-induced mice showed a clear change in the redox status around the hippocampus after PTZ. To examine the role of antioxidants on the brain redox status, the levels of antioxidants were measured in brain tissues of control and PTZ-induced mice. Significantly lower concentrations of glutathione in the hippocampus of PTZ-kindled mice were detected compared with control. From the results of both EPR imaging and the biochemical assay, the hippocampus was found to be susceptible to oxidative damage in the PTZ-induced animal model of epilepsy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Pulse sequences for contrast-enhanced magnetic resonance imaging

International Nuclear Information System (INIS)

Graves, Martin J.

2007-01-01

The theory and application of magnetic resonance imaging (MRI) pulse sequences following the administration of an exogenous contrast agent are discussed. Pulse sequences are categorised according to the contrast agent mechanism: changes in proton density, relaxivity, magnetic susceptibility and resonant frequency shift. Applications in morphological imaging, magnetic resonance angiography, dynamic imaging and cell labelling are described. The importance of optimising the pulse sequence for each application is emphasised

Early magnetic resonance imaging and histologic findings in a model of avascular necrosis of femoral head

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Takuya [Kanazawa Univ. (Japan). School of Medicine

1997-12-01

The present study was performed to examine early MR images and histologic findings using a canine model of avascular necrosis of femoral head (ANFH). The ANFH model was surgically induced. At three days, 1, 2 and 4 weeks after surgery, the proximal femurs were excised. MR images were obtained in 4 dogs at 3 days and 7 dogs at each of the other intervals. Histologic examinations were performed on 7 dogs at each interval. Three days after surgery, MR showed almost no abnormal findings. Histologic changes included edematous bone marrow and bleeding in the bone marrow in some regions. One week after surgery, empty lacunae in trabecular bones and immature fibrous tissues in the bone marrow were seen in some cases, but appositional bone was not yet apparent. In only one case, abnormal MR findings -a ringlike pattern- were seen. Two weeks after surgery, 4 cases showed appositional bones on histology and abnormalities on MR images. Four weeks after surgery, fibrous tissues had matured and appositional bones had increased. Therefore, all 7 cases showed MR imaging abnormalities. Abnormal MR images included a ringlike pattern, and homogeneous and inhomogeneous patterns. These results indicated that MR imaging shows abnormality 2 weeks after surgery at the latest. (author)

Magnetic resonance imaging- physical principles and clinical application

International Nuclear Information System (INIS)

Tavri, Omprakash J.

1996-01-01

The advances in equipment and knowledge related to radiology are occurring at an astonishingly rapid rate. On November 8, 1895, William Conrad Roentgen discovered x-rays. In 1972, Godfrey Hounsfield and George Ambrose introduced computec tomography at a meeting of the British Institute of Radiology. In the same year, Paul Lauterbur published the idea of spatially resolving nuclear magnetic resonance samples, naming it zeugmatography. In 1977, Waldo Hinshaw and co-workers published a magnetic resonance image of a human hand and wrist, and by 1981 several centres were obtaining clinical magnetic resonance (MR) images. In a very short time, magnetic resonance imaging (MRI) has gained acceptance as a clinically useful imaging tool. (author)

Far-field super-resolution imaging of resonant multiples

KAUST Repository

Guo, Bowen

2016-05-20

We demonstrate for the first time that seismic resonant multiples, usually considered as noise, can be used for super-resolution imaging in the far-field region of sources and receivers. Tests with both synthetic data and field data show that resonant multiples can image reflector boundaries with resolutions more than twice the classical resolution limit. Resolution increases with the order of the resonant multiples. This procedure has important applications in earthquake and exploration seismology, radar, sonar, LIDAR (light detection and ranging), and ultrasound imaging, where the multiples can be used to make high-resolution images.

Prenatal diagnosis of conjoined twins by magnetic resonance imaging: report of two cases

International Nuclear Information System (INIS)

Souza, Alex Sandro Rolland de; Medeiros, Cynthia Coelho de; Lins, Glaucia Virginia de Queiroz; Noronha Neto, Carlos; Lima, Marcelo Marques de Souza

2006-01-01

Conjoined twins have a rare prevalence and special curiosity among physicians and the general population. The reported frequency varies from 1:50,000 to 1:200,000 pregnancies. Its early diagnosis becomes very important when we think about pregnancy management, method of delivery and neonatal care. We describe two cases of conjoined twins diagnosed by ultrasound and magnetic resonance during prenatal care with the aim to better studying the fetus anatomy. The first conjoined twins were cephalopagus sharing head, thorax and abdominal wall and with two pelvis and four arms and four legs. The second were thoracopagus, united by thorax and part of abdomen. Magnetic resonance imaging contribution was not important to diagnose conjoined twins. However, it was useful to describe the shared organs, contributing to define fetal outcome. (author)

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... it is useful to bring that to the attention of the technologist or scheduler before the exam. ... patient for magnetic resonance imaging (MRI) exam. View full size with caption Pediatric Content Some imaging tests ...

Venous reflux on contrast-enhanced head and neck magnetic resonance angiography: Analysis of causative factors

Energy Technology Data Exchange (ETDEWEB)

Shin, Dong Jae; Lee, Eun Ja [Dept. of Radiology, Dongguk University Ilsan Hospital, Goyang (Korea, Republic of); Bae, Jong Myon [Dept. of Preventive Medicine, Jeju National University School of Medicine, Jeju (Korea, Republic of)

2016-12-15

The purpose of this study was to analyze the causative factors of venous reflux on contrast-enhanced head and neck magnetic resonance angiography. We retrospectively reviewed 150 patients with right-arm injections and 150 patients with left-arm injections. We included the age, gender, body mass index, history of hypertension, and history of diabetes mellitus in the evaluation of all patients. We measured the shortest width of the left or right brachiocephalic vein (BCV), the diameter of the aortic arch, and the distance between the sternum and vertebral body. The relationship between these factors and the venous reflux was analyzed. In patients with venous reflux, we performed qualitative image scoring for suboptimal images. In patients with venous reflux, the image quality of the left-arm injection group was significantly inferior to the image quality of the right-arm injection group. The mean age and the male-to-female ratio of patients with venous reflux were significantly higher than those of patients without venous reflux. In patients receiving the left-arm injection, the mean shortest width of the left BCV was significantly narrower in patients with venous reflux than in patients without venous reflux. A left-arm injection should be avoided, especially in elderly patients, to acquire an optimal image.

Venous reflux on contrast-enhanced head and neck magnetic resonance angiography: Analysis of causative factors

International Nuclear Information System (INIS)

Shin, Dong Jae; Lee, Eun Ja; Bae, Jong Myon

2016-01-01

The purpose of this study was to analyze the causative factors of venous reflux on contrast-enhanced head and neck magnetic resonance angiography. We retrospectively reviewed 150 patients with right-arm injections and 150 patients with left-arm injections. We included the age, gender, body mass index, history of hypertension, and history of diabetes mellitus in the evaluation of all patients. We measured the shortest width of the left or right brachiocephalic vein (BCV), the diameter of the aortic arch, and the distance between the sternum and vertebral body. The relationship between these factors and the venous reflux was analyzed. In patients with venous reflux, we performed qualitative image scoring for suboptimal images. In patients with venous reflux, the image quality of the left-arm injection group was significantly inferior to the image quality of the right-arm injection group. The mean age and the male-to-female ratio of patients with venous reflux were significantly higher than those of patients without venous reflux. In patients receiving the left-arm injection, the mean shortest width of the left BCV was significantly narrower in patients with venous reflux than in patients without venous reflux. A left-arm injection should be avoided, especially in elderly patients, to acquire an optimal image

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... As the hydrogen atoms return to their usual alignment, they emit different amounts of energy that vary ... story about radiology? Share your patient story here Images × Image Gallery Radiologist prepping patient for magnetic resonance ...

Magnetic Resonance Imaging (MRI): Lumbar Spine (For Parents)

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Lumbar Spine KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Lumbar Spine What's in this article? ...

Role of chelates in magnetic resonance imaging studies

Directory of Open Access Journals (Sweden)

Tripathi Laxmi

2009-01-01

Full Text Available Imaging studies are tests performed with a variety of techniques that produce pictures of the inside of a patient′s body. Magnetic resonance imaging (MRI is an imaging technique based on the principles of nuclear magnetic resonance. MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. Chelates have a wide application in such imaging techniques. Chelates in imaging studies are used alone as radioactive agents or conjugated to monoclonal antibodies or to DNA as radioactive agents. Technetium chelates and gadolinium chelates are being widely used as magnetic resonance contrast media.

Clinical usefulness of a newly-developed head and neck surface coil for MR imaging

International Nuclear Information System (INIS)

Shimada, Morio; Kogure, Takashi; Hayashi, Sanshin

1995-01-01

To obtain correct diagnosis at early stages of cervical lymph node swelling, especially cases with suspected epipharyngeal carcinoma, and cerebral arterial sclerotic diseases, high-quality MR images visualizing the entire head and neck structures and vessels are of crucial importance. When obtaining images of head and neck regions using a head coil, signal intensity (SI) and signal to noise ratio (SNR) of regions below the hypopharynx are weakened. Moreover, when obtaining images of head and neck regions using an anterior neck coil, SI and SNR of upper regions of epipharynx are also weakened. In an attempt to solve these problems, we developed a new head and neck surface coil for MR imaging. With this new coil we were able to obtain better images (153 cases) from regions below the hypopharynx to the upper regions of the epipharynx in the same time as images obtained using the head coil and anterior neck coil. 2D TOF MR angiographic images (11 cases) obtained by the head and neck surface coil are superior to 2D TOF angiographic images obtained by the anterior neck coil. MR images obtained with this improved method are valuable in the evaluation and management of head and neck region disease. (author)

Clinical utility of MR FLAIR imaging for head injuries

Energy Technology Data Exchange (ETDEWEB)

Ashikaga, Ryuichiro [Kinki Univ., Osaka-Sayama, Osaka (Japan). School of Medicine

1996-12-01

To study the utility of fluid attenuated inversion recovery (FLAIR) MR images in the evaluation of traumatic head injury, 56 patients with traumatic head injuries were examined with long TR/TE spin-echo (SE) sequences and FLAIR sequences. In 40 of them, long TR/short TE images were added to those sequences. Careful readings of MR images were done by two well-trained neuroradiologists. The chi-square test was used for statistical evaluation of our results. The relative sensitivities of FLAIR images were significantly better than those of long TR/TE, long TR/short TE images for the detection of diffuse axonal injury (p<0.01), cortical contusion (p<0.01), and subdural hematoma (p<0.01 for long TR/TE, p<0.05 for long TR/short TE). The number of cases of epidural hematoma and brainstem injury was too small for statistical significance to be determined. In 9 patients with corpus callosum injuries. FLAIR images demonstrated the lesions as abnormally high signal intensity in the septum pellucidum and fornix. Only sagittal FLAIR images could definitely discriminate the traumatic lesions of the fornix from the surrounding CSF. In addition, FLAIR images could easily discriminate DAI of the corpus callosum from CSF of the cavum velli interpositi. MR FLAIR images were found to be useful for detecting traumatic head injuries. (author)

Clinical, radiographic, and magnetic resonance imaging findings of gastrocnemius musculotendinopathy in various dog breeds.

Science.gov (United States)

Kaiser, Susanne M; Harms, Oliver; Konar, Martin; Staudacher, Anne; Langer, Anna; Thiel, Cetina; Kramer, Martin; Schaub, Sebastian; von Pückler, Kerstin H

2016-11-23

To describe clinical, radiographic, and magnetic resonance imaging (MRI) findings in 16 dogs diagnosed with gastrocnemius musculotendinopathy. Retrospective evaluation of medical records, radiographs, and MRI results, as well as follow-up completed by telephone questionnaire. Most dogs had chronic hindlimb lameness with no history of trauma or athletic activities. Clinical examination revealed signs of pain on palpation without stifle joint instability. Seven dogs had radiographic signs of osteophyte formation on the lateral fabella. Magnetic resonance imaging revealed T2 hyperintensity and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. Changes were found in the lateral and medial heads of the gastrocnemius. Conservative treatment resulted in return to full function in 11 dogs. Two dogs showed partial restoration of normal function, one dog showed no improvement. Two dogs were lost to follow-up. Gastrocnemius musculotendinopathy is a potential cause of chronic hindlimb lameness in medium to large breed dogs. A history of athletic activity must not necessarily be present. Magnetic resonance imaging shows signal changes and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. A combination of T1 pre- and post-contrast administration and T2 weighted sequences completed by a fat-suppressed sequence in the sagittal plane are well-suited for diagnosis. Conservative treatment generally results in return to normal function.

Magnetic resonance imaging in the evaluation of periosteal reactions

Energy Technology Data Exchange (ETDEWEB)

Nogueira-Barbosa, Marcello Henrique; Trad, Clovis Simao; Muglia, Valdair Francisco; Elias Junior, Jorge; Simao, Marcelo Novelino, E-mail: marcello@fmrp.usp.b [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Centro de Ciencias das Imagens e Fisica Medica; Sa, Jose Luiz de [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas; Oliveira, Rodrigo Cecilio Vieira de [Clinica de Diagnostico por Imagem Tomoson, Aracatuba, SP (Brazil); Engel, Edgard Eduard [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Biomecanica, Medicina e Reabilitacao do Aparelho Locomotor

2010-07-15

The objective of the present essay was to encourage a careful evaluation of periosteal reactions on magnetic resonance images. The initial approach to bone lesions is made by conventional radiography and, based on the imaging findings, periosteal reactions are classified into classical subtypes. Although magnetic resonance imaging is considered as the gold standard for local staging of bone tumors, the utilization of such method in the study of periosteal reactions related to focal bone lesions has been poorly emphasized, with relatively few studies approaching this subject. The literature review revealed a study describing an experimental animal model of osteomyelitis suggesting that magnetic resonance imaging is superior to other imaging methods in the early identification of periosteal reactions. Another study has suggested a good correlation between conventional radiography and magnetic resonance imaging in the identification and classification of periosteal reactions in cases of osteosarcoma. The present essay illustrates cases of periosteal reactions observed at magnetic resonance imaging in correlation with findings of conventional radiography or other imaging methods. (author)

Magnetic resonance imaging in the evaluation of periosteal reactions

International Nuclear Information System (INIS)

Nogueira-Barbosa, Marcello Henrique; Trad, Clovis Simao; Muglia, Valdair Francisco; Elias Junior, Jorge; Simao, Marcelo Novelino; Engel, Edgard Eduard

2010-01-01

The objective of the present essay was to encourage a careful evaluation of periosteal reactions on magnetic resonance images. The initial approach to bone lesions is made by conventional radiography and, based on the imaging findings, periosteal reactions are classified into classical subtypes. Although magnetic resonance imaging is considered as the gold standard for local staging of bone tumors, the utilization of such method in the study of periosteal reactions related to focal bone lesions has been poorly emphasized, with relatively few studies approaching this subject. The literature review revealed a study describing an experimental animal model of osteomyelitis suggesting that magnetic resonance imaging is superior to other imaging methods in the early identification of periosteal reactions. Another study has suggested a good correlation between conventional radiography and magnetic resonance imaging in the identification and classification of periosteal reactions in cases of osteosarcoma. The present essay illustrates cases of periosteal reactions observed at magnetic resonance imaging in correlation with findings of conventional radiography or other imaging methods. (author)

Extending RTM Imaging With a Focus on Head Waves

Science.gov (United States)

Holicki, Max; Drijkoningen, Guy

2016-04-01

Conventional industry seismic imaging predominantly focuses on pre-critical reflections, muting post-critical arrivals in the process. This standard approach neglects a lot of information present in the recorded wave field. This negligence has been partially remedied with the inclusion of head waves in more advanced imaging techniques, like Full Waveform Inversion (FWI). We would like to see post-critical information leave the realm of labour-intensive travel-time picking and tomographic inversion towards full migration to improve subsurface imaging and parameter estimation. We present a novel seismic imaging approach aimed at exploiting post-critical information, using the constant travel path for head-waves between shots. To this end, we propose to generalize conventional Reverse Time Migration (RTM) to scenarios where the sources for the forward and backward propagated wave-fields are not coinciding. RTM functions on the principle that backward propagated receiver data, due to a source at some locations, must overlap with the forward propagated source wave field, from the same source location, at subsurface scatterers. Where the wave-fields overlap in the subsurface there is a peak at the zero-lag cross-correlation, and this peak is used for the imaging. For the inclusion of head waves, we propose to relax the condition of coincident sources. This means that wave-fields, from non-coincident-sources, will not overlap properly in the subsurface anymore. We can make the wave-fields overlap in the subsurface again, by time shifting either the forward or backward propagated wave-fields until the wave-fields overlap. This is the same as imaging at non-zero cross-correlation lags, where the lag is the travel time difference between the two wave-fields for a given event. This allows us to steer which arrivals we would like to use for imaging. In the simplest case we could use Eikonal travel-times to generate our migration image, or we exclusively image the subsurface

Imaging of the head and neck. 2. rev. and enl. ed

Energy Technology Data Exchange (ETDEWEB)

Mafee, M.F.; Valvassori, G.E. [University of Illinois, Chicago, IL (United States); Becker, M. [Geneva University Hospital (Switzerland)

2004-07-01

Remarkable advances in medical diagnostic imaging have been made during the past three decades. The development of new imaging techniques and continuous improvements in the display of digital images have opened new horizons in the study of head and neck anatomy and pathology. The American Society of Head and Neck Radiology (ASHNR) and its European and Asiatic counterparts evolved because of the emerging awareness of the roles that head and neck radiologists play in the diagnosis and management of head and neck, base of the skull, neuro-ophthalmologic and neuro-otologic diseases. This edition continues the tradition of excellence set by the first edition of Valvassori's Head and Neck Imaging (which was also the first textbook in head and neck radiology), and provides a comprehensive review of the most pertinent and up-to-date knowledge in the field of head and neck imaging. The content of this edition has been organized into 12 chapters according to anatomic regions. It now includes new material on the temporomandibular joint, the lacrimal drainage system, dental scanning, fibro-osseous and cartilaginous lesions of the head and neck, MRI sialography, MR interventional technique, and thyroid and parathyroid glands. All chapters have been expanded to address new developments in the field and to stress the importance of imaging anatomy, pathologic correlation, and pertinent clinical data. For each anatomic region, the embryology and anatomy are introduced, followed by congenital and developmental disorders, inflammatory processes, benign and malignant neoplastic diseases, trauma, and postoperative changes. The detailed reference lists in each chapter include key references and are as recent as possible. Care has been taken to include exquisitely reproduced illustrations that provide the maximum of pertinent information. It is our hope that this textbook will be useful to students and physicians in the fields of radiology, otolaryngology, neurootology, rhinology

Imaging of the head and neck. 2. rev. and enl. ed.

International Nuclear Information System (INIS)

Mafee, M.F.; Valvassori, G.E.; Becker, M.

2004-01-01

Remarkable advances in medical diagnostic imaging have been made during the past three decades. The development of new imaging techniques and continuous improvements in the display of digital images have opened new horizons in the study of head and neck anatomy and pathology. The American Society of Head and Neck Radiology (ASHNR) and its European and Asiatic counterparts evolved because of the emerging awareness of the roles that head and neck radiologists play in the diagnosis and management of head and neck, base of the skull, neuro-ophthalmologic and neuro-otologic diseases. This edition continues the tradition of excellence set by the first edition of Valvassori's Head and Neck Imaging (which was also the first textbook in head and neck radiology), and provides a comprehensive review of the most pertinent and up-to-date knowledge in the field of head and neck imaging. The content of this edition has been organized into 12 chapters according to anatomic regions. It now includes new material on the temporomandibular joint, the lacrimal drainage system, dental scanning, fibro-osseous and cartilaginous lesions of the head and neck, MRI sialography, MR interventional technique, and thyroid and parathyroid glands. All chapters have been expanded to address new developments in the field and to stress the importance of imaging anatomy, pathologic correlation, and pertinent clinical data. For each anatomic region, the embryology and anatomy are introduced, followed by congenital and developmental disorders, inflammatory processes, benign and malignant neoplastic diseases, trauma, and postoperative changes. The detailed reference lists in each chapter include key references and are as recent as possible. Care has been taken to include exquisitely reproduced illustrations that provide the maximum of pertinent information. It is our hope that this textbook will be useful to students and physicians in the fields of radiology, otolaryngology, neurootology, rhinology, head

Making the most of the imaging we have: using head MRI to estimate body composition

International Nuclear Information System (INIS)

Lack, C.M.; Lesser, G.J.; Umesi, U.N.; Bowns, J.; Chen, M.Y.; Case, D.; Hightower, R.C.; Johnson, A.J.

2016-01-01

Aim: To investigate the use of clinical head magnetic resonance imaging (MRI) in determining body composition and to evaluate how well it correlates with established measures based on abdominal computed tomography (CT). Materials and methods: Ninety-nine consecutive patients were identified who had undergone both brain MRI and abdominal CT within a 2-week span. Volumes of fat and muscle in the extracranial head were measured utilising several techniques by both abdominal CT and head MRI. Results: MRI-based total fat volumes in the head correlated with CT-based measurements of fat in the abdomen using both single-section (r=0.64, p<0.01) and multisection (r=0.60, p<0.01) techniques. No significant correlation was found between muscle volumes in the abdomen and head. Conclusion: Based on the present results, head MRI-based measures may provide a useful surrogate for CT measurements of abdominal fat, particularly in patients with neurological cancers, as head MRI (and not abdominal CT) is routinely and repeatedly obtained for the purpose of clinical care for these patients. - Highlights: • We compared body composition using brain MRI with previously proven abdominal CT. • Fat and muscle volumes of the extracranial compartment can be measured by MRI. • Muscle volume in the face does not correlate with abdominal muscle volume. • Fat volume in the face can be used as a surrogate for abdominal fat volume.

Children's (Pediatric) Magnetic Resonance Imaging

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Full Text Available ... of which shows a thin slice of the body. The images can then be studied from different angles by ... about radiology? Share your patient story here Images ... Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's ( ...

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. MRI ...

Normal perinatal and paediatric postmortem magnetic resonance imaging appearances

Energy Technology Data Exchange (ETDEWEB)

Arthurs, Owen J. [Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom); UCL Institute of Child Health, London (United Kingdom); Barber, Joy L. [Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom); Taylor, Andrew M. [Cardiorespiratory Division, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom); UCL Institute of Cardiovascular Science, Centre for Cardiovascular Imaging, London (United Kingdom); Sebire, Neil J. [UCL Institute of Child Health, London (United Kingdom); Department of Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom)

2015-04-01

As postmortem imaging becomes more widely used following perinatal and paediatric deaths, the correct interpretation of images becomes imperative, particularly given the increased use of postmortem magnetic resonance imaging. Many pathological processes may have similar appearances in life and following death. A thorough knowledge of normal postmortem changes is therefore required within postmortem magnetic resonance imaging to ensure that these are not mistakenly interpreted as significant pathology. Similarly, some changes that are interpreted as pathological if they occur during life may be artefacts on postmortem magnetic resonance imaging that are of limited significance. This review serves to illustrate briefly those postmortem magnetic resonance imaging changes as part of the normal changes after death in fetuses and children, and highlight imaging findings that may confuse or mislead an observer to identifying pathology where none is present. (orig.)

Nuclear magnetic resonance imaging

International Nuclear Information System (INIS)

Young, I.R.

1984-01-01

In a method of imaging a body in which nuclear magnetic resonance is excited in a region including part of the body, and the free induction decay signal is measured, a known quantity of a material of known nuclear magnetic resonance properties, for example a bag of water, is included in the region so as to enhance the measured free induction decay signal. This then reduces the generation of noise during subsequent processing of the signal. (author)

Avascular necrosis of the femoral head; Chronological change of MR images

Energy Technology Data Exchange (ETDEWEB)

Kokubo, Takeshi; Takatori, Yoshio; Kamogawa, Morihide; Nakamura, Toshitaka; Ninomiya, Setsuo; Yoshikawa, Kohki; Itai, Yuji; Iio, Masahiro; Mitamura, Tadayuki [Tokyo Univ. (Japan). Faculty of Medicine

1990-04-01

T1-weighted MR images of thirty-six hips in 25 patients with avascular necrosis of the femoral head were obtained two to five times during the course of 2 to 26 months. We investigated these MR images in the light of the chronological change and compared them with plain radiographs. MR images changes in 16 femoral head; in general, the abnormal low intensity area in the femoral head reduced in extent and the internal high intensity area became smaller of disappeared. Thirteen femoral heads among them became more flattened on plain radiographs in the same period. It is noted that four different zones are defined in the femoral head after bone necrosis takes place: the dead bone marrow, the dead marrow which still contains fat, the reactive interface and the hyperemic bone marrow. In T1-weighted MR images, the dead bone marrow, the reactive interface and the hyperemic bone marrow are demonstrated as low intensity area, while the dead marrow containing fat may remain high in intensity. On the basis of this knowledge of histopathology and MR images of this disease, we suggest that reduction of the abnormal low intensity area and disappearance of the internal high intensity area on MR images can be regarded as diminution of hyperemia in the living bone marrow and loss of fat in the dead bone marrow, respectively. (author).

TU-F-CAMPUS-I-04: Head-Only Asymmetric Gradient System Evaluation: ACR Image Quality and Acoustic Noise

Energy Technology Data Exchange (ETDEWEB)

Weavers, P; Shu, Y; Tao, S; Bernstein, M [Mayo Clinic, Rochester, Minnesota (United States); Lee, S; Piel, J; Foo, T [GE Global Research, Niskayuna, NY (United States); Mathieu, J-B [GE Healthcare, Florence, SC (Italy)

2015-06-15

Purpose: A high-performance head-only magnetic resonance imaging gradient system with an acquisition volume of 26 cm employing an asymmetric design for the transverse coils has been developed. It is able to reach a magnitude of 85 mT/m at a slew rate of 700 T/m/s, but operated at 80 mT/m and 500 T/m/s for this test. A challenge resulting from this asymmetric design is that the gradient nonlinearly exhibits both odd- and even-ordered terms, and as the full imaging field of view is often used, the nonlinearity is pronounced. The purpose of this work is to show the system can produce clinically useful images after an on-site gradient nonlinearity calibration and correction, and show that acoustic noise levels fall within non-significant risk (NSR) limits for standard clinical pulse sequences. Methods: The head-only gradient system was inserted into a standard 3T wide-bore scanner without acoustic damping. The ACR phantom was scanned in an 8-channel receive-only head coil and the standard American College of Radiology (ACR) MRI quality control (QC) test was performed. Acoustic noise levels were measured for several standard pulse sequences. Results: Images acquired with the head-only gradient system passed all ACR MR image quality tests; Both even and odd-order gradient distortion correction terms were required for the asymmetric gradients to pass. Acoustic noise measurements were within FDA NSR guidelines of 99 dBA (with assumed 20 dBA hearing protection) A-weighted and 140 dB for peak for all but one sequence. Note the gradient system was installed without any shroud or acoustic batting. We expect final system integration to greatly reduce noise experienced by the patient. Conclusion: A high-performance head-only asymmetric gradient system operating at 80 mT/m and 500 T/m/s conforms to FDA acoustic noise limits in all but one case, and passes all the ACR MR image quality control tests. This work was supported in part by the NIH grant 5R01EB010065.

TU-F-CAMPUS-I-04: Head-Only Asymmetric Gradient System Evaluation: ACR Image Quality and Acoustic Noise

International Nuclear Information System (INIS)

Weavers, P; Shu, Y; Tao, S; Bernstein, M; Lee, S; Piel, J; Foo, T; Mathieu, J-B

2015-01-01

Purpose: A high-performance head-only magnetic resonance imaging gradient system with an acquisition volume of 26 cm employing an asymmetric design for the transverse coils has been developed. It is able to reach a magnitude of 85 mT/m at a slew rate of 700 T/m/s, but operated at 80 mT/m and 500 T/m/s for this test. A challenge resulting from this asymmetric design is that the gradient nonlinearly exhibits both odd- and even-ordered terms, and as the full imaging field of view is often used, the nonlinearity is pronounced. The purpose of this work is to show the system can produce clinically useful images after an on-site gradient nonlinearity calibration and correction, and show that acoustic noise levels fall within non-significant risk (NSR) limits for standard clinical pulse sequences. Methods: The head-only gradient system was inserted into a standard 3T wide-bore scanner without acoustic damping. The ACR phantom was scanned in an 8-channel receive-only head coil and the standard American College of Radiology (ACR) MRI quality control (QC) test was performed. Acoustic noise levels were measured for several standard pulse sequences. Results: Images acquired with the head-only gradient system passed all ACR MR image quality tests; Both even and odd-order gradient distortion correction terms were required for the asymmetric gradients to pass. Acoustic noise measurements were within FDA NSR guidelines of 99 dBA (with assumed 20 dBA hearing protection) A-weighted and 140 dB for peak for all but one sequence. Note the gradient system was installed without any shroud or acoustic batting. We expect final system integration to greatly reduce noise experienced by the patient. Conclusion: A high-performance head-only asymmetric gradient system operating at 80 mT/m and 500 T/m/s conforms to FDA acoustic noise limits in all but one case, and passes all the ACR MR image quality control tests. This work was supported in part by the NIH grant 5R01EB010065

Osteochondral lesion of the bilateral femoral heads in a young athletic patient

Energy Technology Data Exchange (ETDEWEB)

Lee, Jung Eun; Ryu, Kyung Nam; Park, Ji Seon; Cho, Yoon Je [Kyung Hee University Hospital, Seoul (Korea, Republic of); Yoon, So Hee; Park, So Young; Jin, Wook [Dept. of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul (Korea, Republic of); Lee, Kyung Ryeol [Dept. of Radiology, Jeju National University Hospital, Jeju (Korea, Republic of)

2014-12-15

Osteochondral lesions of the femoral head are uncommon and few studies have reported their imaging findings. Since joints are at risk of early degeneration after osteochondral damage, timely recognition is important. Osteochondral lesions of femoral head may often be necessary to differentiate from avascular necrosis. Here, we report a case of osteochondral lesions on bilateral femoral heads. This lesion manifested as subchondral cysts in initial radiographs, which led to further evaluation by computed tomography arthrography and magnetic resonance imaging, which revealed overlying cartilage defects.

Principles of magnetic resonance imaging

International Nuclear Information System (INIS)

Mlynarik, V.; Tkac, I.; Srbecky, M.

1995-01-01

The aim of this review is to describe and explain the basic principles of magnetic resonance imaging. The first part of the text is devoted to the phenomenon of magnetic resonance (the interaction of RF magnetic field with the set of magnetic moments in the homogeneous magnetic field) and to relaxation processes. Then, the creation of MR image is described (slice selection, phase and frequency encoding of spatial information). The basic and the most frequently used techniques are explained (spin echo, gradient echo). The way the repetition and echo times influence the image quality and contrast (T1 or T2 weighing) is described. The part with the technical description of the MR equipment is included in the review. The MR imagination examination are compared with X-ray computer tomography technique

Magnetic resonance imaging of breast implants.

Science.gov (United States)

Shah, Mala; Tanna, Neil; Margolies, Laurie

2014-12-01

Silicone breast implants have significantly evolved since their introduction half a century ago, yet implant rupture remains a common and expected complication, especially in patients with earlier-generation implants. Magnetic resonance imaging is the primary modality for assessing the integrity of silicone implants and has excellent sensitivity and specificity, and the Food and Drug Administration currently recommends periodic magnetic resonance imaging screening for silent silicone breast implant rupture. Familiarity with the types of silicone implants and potential complications is essential for the radiologist. Signs of intracapsular rupture include the noose, droplet, subcapsular line, and linguine signs. Signs of extracapsular rupture include herniation of silicone with a capsular defect and extruded silicone material. Specific sequences including water and silicone suppression are essential for distinguishing rupture from other pathologies and artifacts. Magnetic resonance imaging provides valuable information about the integrity of silicone implants and associated complications.

ANATOMICAL STUDY OF CRANIAL NERVE EMERGENCE AND SKULL FORAMINA IN THE HORSE USING MAGNETIC RESONANCE IMAGING AND COMPUTED TOMOGRAPHY.

Science.gov (United States)

Gonçalves, Rita; Malalana, Fernando; McConnell, James Fraser; Maddox, Thomas

2015-01-01

For accurate interpretation of magnetic resonance (MR) images of the equine brain, knowledge of the normal cross-sectional anatomy of the brain and associated structures (such as the cranial nerves) is essential. The purpose of this prospective cadaver study was to describe and compare MRI and computed tomography (CT) anatomy of cranial nerves' origins and associated skull foramina in a sample of five horses. All horses were presented for euthanasia for reasons unrelated to the head. Heads were collected posteuthanasia and T2-weighted MR images were obtained in the transverse, sagittal, and dorsal planes. Thin-slice MR sequences were also acquired using transverse 3D-CISS sequences that allowed mutliplanar reformatting. Transverse thin-slice CT images were acquired and multiplanar reformatting was used to create comparative images. Magnetic resonance imaging consistently allowed visualization of cranial nerves II, V, VII, VIII, and XII in all horses. The cranial nerves III, IV, and VI were identifiable as a group despite difficulties in identification of individual nerves. The group of cranial nerves IX, X, and XI were identified in 4/5 horses although the region where they exited the skull was identified in all cases. The course of nerves II and V could be followed on several slices and the main divisions of cranial nerve V could be distinguished in all cases. In conclusion, CT allowed clear visualization of the skull foramina and occasionally the nerves themselves, facilitating identification of the nerves for comparison with MRI images. © 2015 American College of Veterinary Radiology.

Magnetic resonance imaging of radiation optic neuropathy

International Nuclear Information System (INIS)

Zimmerman, C.F.; Schatz, N.J.; Glaser, J.S.

1990-01-01

Three patients with delayed radiation optic neuropathy after radiation therapy for parasellar neoplasms underwent magnetic resonance imaging. The affected optic nerves and chiasms showed enlargement and focal gadopentetate dimeglumine enhancement. The magnetic resonance imaging technique effectively detected and defined anterior visual pathway changes of radionecrosis and excluded the clinical possibility of visual loss because of tumor recurrence

Advances in otolaryngology-Head and neck surgery. Volume 1

International Nuclear Information System (INIS)

Myers, E.N.; Bluestone, C.D.

1987-01-01

This book consists of 14 sections. The section titles are: The impact of AIDS on otolaryngology--head and neck surgery; The management of sleep apneas and snoring; Antimicrobial agents for infections in the ear, nose, and throat--head and neck; Nasal allergy: Medical and surgical treatment; Uses of computerized tomography and magnetic resonance imaging in temporal bone imaging; Surgical management of otitis media with effusion; middle ear reconstruction: Current status; Cochlear implants: an overview; Diagnosis and management of acute facial paralysis; The use of the laser in head and neck surgery; The management and prevention of subglottic stenosis in infants and children; Management of the mass in the thyroid; Suction-assisted lipectomy of the head and neck area; and Ambulatory surgery

Advances in otolaryngology-Head and neck surgery. Volume 1

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Myers, E.N. (Univ. of Pittsburgh School of Medicine, Pittsburgh, PA (US)); Bluestone, C.D. (Univ. of Pittsburgh, Pittsburgh, PA (US))

1987-01-01

This book consists of 14 sections. The section titles are: The impact of AIDS on otolaryngology--head and neck surgery; The management of sleep apneas and snoring; Antimicrobial agents for infections in the ear, nose, and throat--head and neck; Nasal allergy: Medical and surgical treatment; Uses of computerized tomography and magnetic resonance imaging in temporal bone imaging; Surgical management of otitis media with effusion; middle ear reconstruction: Current status; Cochlear implants: an overview; Diagnosis and management of acute facial paralysis; The use of the laser in head and neck surgery; The management and prevention of subglottic stenosis in infants and children; Management of the mass in the thyroid; Suction-assisted lipectomy of the head and neck area; and Ambulatory surgery.

A Novel Magnetic Resonance Imaging (MRI) Approach for Measuring Weak Electric Currents Inside the Human Brain

DEFF Research Database (Denmark)

Göksu, Cihan

of individual ohmic conductivity values may open up the possibility of creating more realistic and accurate head models, which may ameliorate the simulations and practical use of NIBS techniques. Magnetic resonance current density imaging (MRCDI) and magnetic resonance electrical impedance tomography (MREIT......Knowing the electrical conductivity and current density distribution inside the human brain will be useful in various biomedical applications, i.e. for improving the efficiency of non-invasive brain stimulation (NIBS) techniques, the accuracy of electroencephalography (EEG......) and magnetoencephalography (MEG) source localization, or localization of pathological tissues. For example, the accuracy of electric field simulations for NIBS techniques is currently reduced by assigning inaccurate ohmic conductivity values taken from literature to different brain tissues. Therefore, the knowledge...

Magnetic resonance imaging of the femoral head to detect avascular necrosis in active rheumatoid arthritis treated with methylprednisolone pulse therapy

NARCIS (Netherlands)

van Vugt, R. M.; Sijbrandij, E. S.; Bijlsma, J. W.

1996-01-01

Efficacious management of patients with avascular necrosis of bone (AVN) necessitates the identification of patients with a high risk of collapse of the femoral head. In this prospective study we imaged both hips of 10 patients with active rheumatoid arthritis, who were treated with

Whole-body magnetic resonance angiography for presurgical planning of free-flap head and neck reconstruction

International Nuclear Information System (INIS)

Kramer, Manuel; Nkenke, Emeka; Kikuchi, Keiichi; Schwab, Siegfried A.; Janka, Rolf; Uder, Michael; Lell, Michael

2012-01-01

Objectives: Aim of the study was to evaluate if a whole-body magnetic resonance angiography (MRA) protocol meets the requirements to evaluate the donor and host site target vessels for planning of microvascular head and neck reconstructions. Patients and methods: In 20 patients, scheduled for reconstruction of the mandible with fibular free flaps, contrast-enhanced whole-body MRA was performed prior to surgery. 32-Channel 1.5-T MR angiograms were acquired using a 2-step contrast (gadobutrol) injection scheme to visualize the arterial vasculature from head to feet. Maximum intensity projection and multiplanar reconstruction technique was employed to visualize MRA data. For image evaluation the arterial tree was divided into 51 segments. The presence of artefacts impairing diagnostic quality was noted. Evaluable segments were assessed regarding the presence of stenoses >50% diameter reduction, occlusions or aneurysms. Results: No adverse reactions or complications occurred. Of 1020 vessel segments 1003 (98.3%) were evaluable. 36 stenoses >50%, 50 occlusions and one aneurysm were observed. In 21 of 40 lower limbs relevant atherosclerotic changes were depicted. Conclusion: Whole-body MRA proved to be a suitable three-dimensional, noninvasive, nonionising modality for preoperative evaluation of the entire arterial vasculature.

Analysis of normal and dysplastic glenohumeral morphology at magnetic resonance imaging in children with neonatal brachial plexus palsy

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Bunt, Fabian van de [VU University Medical Center, Amsterdam (Netherlands); Pearl, Michael L.; Lee, Eric K.; Peng, Lauren; Didomenico, Paul [Kaiser Permanente, Los Angeles, CA (United States)

2017-09-15

Glenoid version and percentage of the humeral head anterior to the scapular line are commonly used 2-D measures to assess deformity of the glenohumeral joint of children with neonatal brachial plexus palsy. To assess whether glenoid version and percentage of the humeral head anterior to the scapular line would be altered by standardizing the measurements to the orientation of the scapula. Twenty-one bilateral magnetic resonance imaging (MRI) scans were evaluated by four reviewers. Measurements were performed on the axial image slices and again after applying 3-D reformatting. Three-dimensional reformatting led to intrapatient corrections up to 25 for version and -30% for percentage of the humeral head anterior to the scapular line. The mean difference on the involved side between clinical and anatomical version across all subjects from all reviewers was 2.2 ± 3.9 (range: -4.5 to 11.5 ). The mean difference in the percentage of the humeral head anterior to the scapular line after reformatting was -1.8% (range: -15.9% to 5.2%). Measurements can differ greatly for the same child depending on technical factors of image acquisition and presentation in the clinical setting. With this study, we present a clinically accessible protocol to correct for scapular orientation from MRI data of children with neonatal brachial plexus palsy. (orig.)

Content Based Retrieval System for Magnetic Resonance Images

International Nuclear Information System (INIS)

Trojachanets, Katarina

2010-01-01

The amount of medical images is continuously increasing as a consequence of the constant growth and development of techniques for digital image acquisition. Manual annotation and description of each image is impractical, expensive and time consuming approach. Moreover, it is an imprecise and insufficient way for describing all information stored in medical images. This induces the necessity for developing efficient image storage, annotation and retrieval systems. Content based image retrieval (CBIR) emerges as an efficient approach for digital image retrieval from large databases. It includes two phases. In the first phase, the visual content of the image is analyzed and the feature extraction process is performed. An appropriate descriptor, namely, feature vector is then associated with each image. These descriptors are used in the second phase, i.e. the retrieval process. With the aim to improve the efficiency and precision of the content based image retrieval systems, feature extraction and automatic image annotation techniques are subject of continuous researches and development. Including the classification techniques in the retrieval process enables automatic image annotation in an existing CBIR system. It contributes to more efficient and easier image organization in the system.Applying content based retrieval in the field of magnetic resonance is a big challenge. Magnetic resonance imaging is an image based diagnostic technique which is widely used in medical environment. According to this, the number of magnetic resonance images is enormously growing. Magnetic resonance images provide plentiful medical information, high resolution and specific nature. Thus, the capability of CBIR systems for image retrieval from large database is of great importance for efficient analysis of this kind of images. The aim of this thesis is to propose content based retrieval system architecture for magnetic resonance images. To provide the system efficiency, feature

Optimization of an Image-Based Talking Head System

Directory of Open Access Journals (Sweden)

Kang Liu

2009-01-01

Full Text Available This paper presents an image-based talking head system, which includes two parts: analysis and synthesis. The audiovisual analysis part creates a face model of a recorded human subject, which is composed of a personalized 3D mask as well as a large database of mouth images and their related information. The synthesis part generates natural looking facial animations from phonetic transcripts of text. A critical issue of the synthesis is the unit selection which selects and concatenates these appropriate mouth images from the database such that they match the spoken words of the talking head. Selection is based on lip synchronization and the similarity of consecutive images. The unit selection is refined in this paper, and Pareto optimization is used to train the unit selection. Experimental results of subjective tests show that most people cannot distinguish our facial animations from real videos.

Assessing joint effusion and bone changes of the head of the mandible in MR images of symptomatic patients

Directory of Open Access Journals (Sweden)

Jefferson Xavier de Oliveira

2013-02-01

Full Text Available The aim of the present study was to investigate the relationship between degenerative bone changes of the head of the mandible and the presence of joint effusion (JE. This study was based on sagittal magnetic resonance imaging (MRI reports of 148 temporomandibular joints (TMJs of 74 patients complaining of pain and/or dysfunction in the TMJ area. The mandible heads were surveyed for osteoarthritis characteristics, which were classified as osteophytosis, sclerosis or erosion. The presence of JE was checked whenever high signal intensity was observed in the articular space. The results evidenced the presence of bone changes in 30% of the sample. Osteophytes and erosions were the changes most commonly observed. JE was reported in 10% of TMJs. The results from the statistical tests revealed that bone changes in the head of the mandible are associated with the presence of JE.

Susceptibility weighted imaging depicts retinal hemorrhages in abusive head trauma

Energy Technology Data Exchange (ETDEWEB)

Zuccoli, Giulio [Children' s Hospital of Pittsburgh of UPMC, Department of Pediatric Radiology, Pittsburgh, PA (United States); Children' s Hospital of Pittsburgh of UPMC, Department of Radiology, Pittsburgh, PA (United States); Panigrahy, Ashok; Haldipur, Anshul; Willaman, Dennis [Children' s Hospital of Pittsburgh of UPMC, Department of Pediatric Radiology, Pittsburgh, PA (United States); Squires, Janet; Wolford, Jennifer [Children' s Hospital of Pittsburgh of UPMC, Division of Child Advocacy, Pittsburgh, PA (United States); Sylvester, Christin; Mitchell, Ellen; Lope, Lee Ann [Children' s Hospital of Pittsburgh of UPMC, Eye Center, Pittsburgh, PA (United States); Nischal, Ken K. [Children' s Hospital of Pittsburgh of UPMC, Eye Center, Pittsburgh, PA (United States); Children' s Hospital of Pittsburgh of UPMC, Division of Pediatric Ophthalmology, Strabismus, and Adult Motility, Eye Center, Pittsburgh, PA (United States); Berger, Rachel P. [Children' s Hospital of Pittsburgh of UPMC, Division of Child Advocacy, Pittsburgh, PA (United States); University of Pittsburgh Medical Center, Safar Center for Resuscitation Research, Pittsburgh, PA (United States)

2013-07-15

This study aims to evaluate the capability of magnetic resonance imaging (MRI) susceptibility weighted images (SWI) in depicting retinal hemorrhages (RH) in abusive head trauma (AHT) compared to the gold standard dilated fundus exam (DFE). This is a retrospective, single institution, observational study on 28 patients with suspected AHT, who had a DFE and also underwent brain MRI-SWI as part of routine diagnostic protocol. Main outcome measures involved evaluation of patients to determine whether the RH could be identified on standard and high-resolution SWI sequences. Of the 21 subjects with RH on DFE, 13 (62 %) were identified by using a standard SWI sequence performed as part of brain MRI protocols. Of the 15 patients who also underwent an orbits SWI protocol, 12 (80 %) were positive for RH. None of the seven patients without RH on of DFE had RH on either standard or high-resolution SWI. Compared with DFE, the MRI standard protocol showed a sensitivity of 75 % which increased to 83 % for the orbits SWI protocol. Our study suggests the usefulness of a tailored high-resolution orbits protocol to detect RH in AHT. (orig.)

Susceptibility weighted imaging depicts retinal hemorrhages in abusive head trauma

International Nuclear Information System (INIS)

Zuccoli, Giulio; Panigrahy, Ashok; Haldipur, Anshul; Willaman, Dennis; Squires, Janet; Wolford, Jennifer; Sylvester, Christin; Mitchell, Ellen; Lope, Lee Ann; Nischal, Ken K.; Berger, Rachel P.

2013-01-01

This study aims to evaluate the capability of magnetic resonance imaging (MRI) susceptibility weighted images (SWI) in depicting retinal hemorrhages (RH) in abusive head trauma (AHT) compared to the gold standard dilated fundus exam (DFE). This is a retrospective, single institution, observational study on 28 patients with suspected AHT, who had a DFE and also underwent brain MRI-SWI as part of routine diagnostic protocol. Main outcome measures involved evaluation of patients to determine whether the RH could be identified on standard and high-resolution SWI sequences. Of the 21 subjects with RH on DFE, 13 (62 %) were identified by using a standard SWI sequence performed as part of brain MRI protocols. Of the 15 patients who also underwent an orbits SWI protocol, 12 (80 %) were positive for RH. None of the seven patients without RH on of DFE had RH on either standard or high-resolution SWI. Compared with DFE, the MRI standard protocol showed a sensitivity of 75 % which increased to 83 % for the orbits SWI protocol. Our study suggests the usefulness of a tailored high-resolution orbits protocol to detect RH in AHT. (orig.)

Dental magnetic resonance imaging

International Nuclear Information System (INIS)

Hilgenfeld, Tim; Bendszus, Martin; Haehnel, Stefan

2016-01-01

Growing distribution and utilization of digital volume tomography (DVT) extend the spectrum of clinical dental imaging. Additional diagnostic value, however, comes along with an increasing amount of radiation. In contrast, magnetic resonance imaging is a radiation free imaging technique. Furthermore, it offers a high soft tissue contrast. Morphological and numerical dental anomalies, differentiation of periapical lesions and exclusion of complications of dental diseases are field of applications for dental MRI. In addition, detection of caries and periodontal lesions and injury of inferior alveolar nerve are promising application areas in the future.

Cranial magnetic resonance imaging

International Nuclear Information System (INIS)

Elster, A.D.

1988-01-01

Cranial Magnetic Resonance Imaging is comprehensive, well structured, and well written. The material is current and well referenced. The illustrations are good and complement the text well. The overall quality of publication is above average. The greatest attribute of the book is its readability. The author demonstrates ample skill in making complex subjects, such as MR physics and imaging of cerebral hemorrhage, easy to understand. The book closes with a detailed atlas on the anatomic appearance of the brain on MR images in the axial, coronal, and sagittal planes

Capsular contracture and possible implant rupture: is magnetic resonance imaging useful?

Science.gov (United States)

Paetau, Alyssa A; McLaughlin, Sarah A; McNeil, Rebecca B; Sternberg, Erez; TerKonda, Sarvam P; Waldorf, James C; Perdikis, Galen

2010-03-01

Currently, magnetic resonance imaging is considered the accepted standard to evaluate breast implant integrity. To evaluate its utility in diagnosing ruptured silicone implants in the setting of capsular contracture and to correlate the preoperative assessment of implant integrity with or without magnetic resonance imaging with operative findings, 319 capsulectomies (171 patients with capsular contractures) were retrospectively reviewed. Preoperative magnetic resonance imaging was done on 160 implants, whereas the remaining 159 were evaluated using only physical examination and/or mammography. Postoperative results were analyzed to determine the sensitivity, specificity, and accuracy of preoperative magnetic resonance imaging in comparison with clinical and/or mammography evaluation alone. Although occasionally valuable, overall, preoperative magnetic resonance imaging was no more accurate than clinical evaluation with or without mammography in predicting implant status: magnetic resonance imaging 124 of 160 (78 percent) and clinical 121 of 159 (76 percent; p = 0.77). In the setting of capsular contracture, physical examination with or without mammogram is as accurate as magnetic resonance imaging in determining implant integrity. Although magnetic resonance imaging is a sensitive diagnostic tool, in symptomatic patients with capsular contracture, it cannot be viewed as infallible.

Evaluation of Marrow Perfusion in the Femoral Head by Dynamic Magnetic Resonance Imaging

Science.gov (United States)

Tsukamoto, Hiroshi; Kang, Young S.; Jones, Lynne C.; Cova, Maria; Herold, Christian J.; McVeigh, Elliot; Hungerford, David S.; Zerhouni, Elias A.

2007-01-01

Rationale and Objectives There is a continuing need for a greater sensitivity of magnetic resonance imaging (MRI) in the diagnosis of avascular necrosis (AVN). Previously, it was demonstrated that a dynamic MRI method, with gadolinium-DTPA (Gd-DTPA) enhancement, can detect acute changes not seen on spin-echo images after arterial occlusion in a dog model. Because venous congestion appears to be a more directly relevant hemodynamic abnormality in a majority of clinical AVN cases, the authors extended the dynamic MRI technique to study changes in venous occlusion. Methods Dynamic MRI of the proximal femur was performed in five adult dogs before and after unilateral ligation of common iliac and lateral circumflex veins. Sixteen sequential gradient-recalled pulse sequence (GRASS) images (time resolution = 45 mseconds, echo time = 9 mseconds, flip angle = 65°) were obtained immediately after a bolus intravenous injection of 0.2 mmol/kg of Gd-DTPA. Simultaneous measurements of regional blood flow were made using the radioactive microsphere method. Results After venous ligation, there was a 25% to 45% decrease in the degree of enhancement compared with preligation values on the ligated side. The decrease in cumulative enhancement (integrated over the entire time course) was statistically significant. The occlusion technique was verified by confirming a statistically significant decrease in blood flow determined by the microsphere method. Conclusions Dynamic Gd-DTPA-enhanced fast MRI technique can detect acute changes in bone marrow perfusion due to venous occlusion. This technique may have applications in the early detection of nontraumatic AVN. PMID:1601616

In Vivo Imaging of Nitric Oxide by Magnetic Resonance Imaging Techniques

Directory of Open Access Journals (Sweden)

Rakesh Sharma

2014-01-01

Full Text Available Nitric oxide (NO biosensors are novel tools for real-time bioimaging of tissue oxygen changes and physiological monitoring of tissue vasculature. Nitric oxide behavior further enhances its role in mapping signal transduction at the molecular level. Spectrometric electron paramagnetic resonance (EPR and fluorometric imaging are well known techniques with the potential for in vivo bioimaging of NO. In tissues, NO is a specific target of nitrosyl compounds for chemical reaction, which provides a unique opportunity for application of newly identified NO biosensors. However, the accuracy and sensitivity of NO biosensors still need to be improved. Another potential magnetic resonance technique based on short term NO effects on proton relaxation enhancement is magnetic resonance imaging (MRI, and some NO biosensors may be used as potent imaging contrast agents for measurement of tumor size by MRI combined with fluorescent imaging. The present review provides supporting information regarding the possible use of nitrosyl compounds as NO biosensors in MRI and fluorescent bioimaging showing their measurement limitations and quantitative accuracy. These new approaches open a perspective regarding bioimaging of NO and the in vivo elucidation of NO effects by magnetic resonance techniques.

Manual of head and neck imaging

International Nuclear Information System (INIS)

Raghavan, Prashant; Mukherjee, Sugoto; Jameson, Mark J.; Wintermark, Max

2014-01-01

Easy-to-read short chapters. Tables, checklists, and algorithms to assist in arriving at a quick diagnosis. Clinical pearls that will enable the radiologist to issue a relevant report. One-stop resource when preparing for radiology and otolaryngology exams. Line diagrams to illustrate key concepts. This book is designed as an easily readable manual that will be of great practical value for radiology and otolaryngology residents during their clinical rotations. Key facts on head and neck imaging are presented in short chapters written in an easily readable style. Line drawings are used to illustrate key concepts, and tables, checklists, and algorithms will enable the readers to arrive at a quick diagnosis. In addition, emphasis is placed on clinical pearls that will assist them in preparing suitable reports. The Manual of Head and Neck Imaging is sized to allow residents to read it completely within a matter of days, and it will also serve as an ideal quick reference guide as different clinical situations arise.

Optimization of MR imaging for extracranial head and neck lesions

International Nuclear Information System (INIS)

Dalley, R.W.; Maravilla, K.R.; Cohen, W.

1989-01-01

The authors have used a 1.5T MR imager to study 28 pathologically proven extracranial head and neck lesions. Multiple pulse sequences were performed pre-and/or post-gadolinium, including T1-weighted, short TI inversion-recovery (STIR), spin-density, and T2-weighted sequences. T1-weighted images provided excellent anatomic detail but relatively poor muscle/lesion contrast. Gadolinium often improved lesion visibility; however, discrimination from surrounding fat was impaired. Postcontrast T2-weighted images seemed to provide better lesion conspicuity than did pre-gadolinium images. STIR imaging provided the highest lesion conspicuity in fatty areas. No single sequence was optimal for all head and neck imaging. The authors analyze the advantages and limitations of each sequence and formulate rational imaging protocols based on the primary region of interest

Dynamic changes in the distribution and time course of blood-brain barrier-permeative nitroxides in the mouse head with EPR imaging: visualization of blood flow in a mouse model of ischemia.

Science.gov (United States)

Emoto, Miho C; Sato-Akaba, Hideo; Hirata, Hiroshi; Fujii, Hirotada G

2014-09-01

Electron paramagnetic resonance (EPR) imaging using nitroxides as redox-sensitive probes is a powerful, noninvasive method that can be used under various physiological conditions to visualize changes in redox status that result from oxidative damage. Two blood-brain barrier-permeative nitroxides, 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (HMP) and 3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-yloxy (MCP), have been widely used as redox-sensitive probes in the brains of small animals, but their in vivo distribution and properties have not yet been analyzed in detail. In this study, a custom-made continuous-wave three-dimensional (3D) EPR imager was used to obtain 3D EPR images of mouse heads using MCP or HMP. This EPR imager made it possible to take 3D EPR images reconstructed from data from 181 projections acquired every 60s. Using this improved EPR imager and magnetic resonance imaging, the distribution and reduction time courses of HMP and MCP were examined in mouse heads. EPR images of living mice revealed that HMP and MCP have different distributions and different time courses for entering the brain. Based on the pharmacokinetics of the reduction reactions of HMP and MCP in the mouse head, the half-lives of HMP and MCP were clearly and accurately mapped pixel by pixel. An ischemic mouse model was prepared, and the half-life of MCP was mapped in the mouse head. Compared to the half-life in control mice, the half-life of MCP in the ischemic model mouse brain was significantly increased, suggesting a shift in the redox balance. This in vivo EPR imaging method using BBB-permeative MCP is a useful noninvasive method for assessing changes in the redox status in mouse brains under oxidative stress. Copyright © 2014 Elsevier Inc. All rights reserved.

Magnetic resonance imaging in sudden deafness

International Nuclear Information System (INIS)

Ramos, Hugo Valter Lisboa; Barros, Flavia Alencar; Penido, Norma de Oliveira; Souza, Ana Claudia Valerio de; Yamaoka, Wellington Yugo; Yamashita, Helio

2005-01-01

The etiology of sudden deafness can remain undetermined despite extensive investigation. This study addresses the value of magnetic resonance imaging in the analysis of sudden deafness patients.Study Design: transversal cohort.Material And Method: In a prospective study, 49 patients attended at otolaryngology emergency room of Federal University of Sao Paulo - Escola Paulista de Medicina, from April 2001 to May 2003, were submitted to magnetic resonance imaging.Results: Magnetic Resonance abnormalities were seen in 23 (46.9%) patients and revealed two tumors suggestive of meningioma, three vestibular schwannomas, thirteen microangiopathic changes of the brain and five (21.7%) pathological conditions of the labyrinth.Conclusion: Sudden deafness should be approached as a symptom common to different diseases. The presence of cerebellopontine angle tumors in 10.2% of our cases, among other treatable causes, justifies the recommendation of gadolinium-enhanced magnetic resonance use, not only to study the auditory peripheral pathway, but to study the whole auditory pathway including the brain. (author)

Diagnostic performance of MR imaging in the assessment of subchondral fractures in avascular necrosis of the femoral head

Energy Technology Data Exchange (ETDEWEB)

Yeh, Lee-Ren [E-Da Hospital and I-Shou University, Department of Radiology, Kaohsiung County (China); Chen, Clement K.H.; Pan, Huay-Ben; Yang, Chien-Fang [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung (China); National Yang-Ming University, School of Medicine, Taipei (China); Huang, Yi-Luan [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung (China)

2009-06-15

A prospective study was conducted to determine the accuracy of routine magnetic resonance (MR) imaging in correctly identifying subchondral fracture in avascular necrosis of the femoral head without apparent focal collapse on standard radiographs. Spiral computed tomography (CT) with coronal and sagittal reformations and routine MR imaging with spin-echo T1WI and fat-suppressed spin-echo T2WI coronal, axial, and sagittal images were performed in 28 hips of 25 patients (M/F = 20:5; age 16-76 years) suffering from early-stage avascular necrosis of the femoral head on standard radiographs. The MR images were reviewed by a musculoskeletal radiologist and a general radiologist in blinded fashion. Using CT as the standard of reference, the accuracy of MR imaging in diagnosing subchondral fractures in avascular necrosis was evaluated. When the diagnoses of the two readers were compared with each other, only 16 of the 28 diagnoses (57.5%) agreed. Seventeen of the 28 MR imaging readings (60.7%) made by the musculoskeletal radiologist and 15 of the 28 (53.5%) made by the general radiologist agreed with those of the CT standard. False-positive diagnosis (that is, diagnosis of fracture when no fracture could be seen on CT) was more common than false-negative diagnosis. The accuracy of routine MR imaging in the evaluation of subchondral fracture is not satisfactory. False-positive diagnosis is not uncommon. Interpretation of routine MR imaging readout should be guarded. (orig.)

Diagnostic performance of MR imaging in the assessment of subchondral fractures in avascular necrosis of the femoral head

International Nuclear Information System (INIS)

Yeh, Lee-Ren; Chen, Clement K.H.; Pan, Huay-Ben; Yang, Chien-Fang; Huang, Yi-Luan

2009-01-01

A prospective study was conducted to determine the accuracy of routine magnetic resonance (MR) imaging in correctly identifying subchondral fracture in avascular necrosis of the femoral head without apparent focal collapse on standard radiographs. Spiral computed tomography (CT) with coronal and sagittal reformations and routine MR imaging with spin-echo T1WI and fat-suppressed spin-echo T2WI coronal, axial, and sagittal images were performed in 28 hips of 25 patients (M/F = 20:5; age 16-76 years) suffering from early-stage avascular necrosis of the femoral head on standard radiographs. The MR images were reviewed by a musculoskeletal radiologist and a general radiologist in blinded fashion. Using CT as the standard of reference, the accuracy of MR imaging in diagnosing subchondral fractures in avascular necrosis was evaluated. When the diagnoses of the two readers were compared with each other, only 16 of the 28 diagnoses (57.5%) agreed. Seventeen of the 28 MR imaging readings (60.7%) made by the musculoskeletal radiologist and 15 of the 28 (53.5%) made by the general radiologist agreed with those of the CT standard. False-positive diagnosis (that is, diagnosis of fracture when no fracture could be seen on CT) was more common than false-negative diagnosis. The accuracy of routine MR imaging in the evaluation of subchondral fracture is not satisfactory. False-positive diagnosis is not uncommon. Interpretation of routine MR imaging readout should be guarded. (orig.)

Electron Paramagnetic Resonance Imaging

Indian Academy of Sciences (India)

Twentieth century bore witness to remarkable scientists whohave advanced our understanding of the brain. Among them,EPR (Electron Paramagnetic Resonance) imaging is particularlyuseful in monitoring hypoxic zones in tumors which arehighly resistant to radiation and chemotherapeutic treatment.This first part of the ...

The role of radiology in head and neck tumours in children

Science.gov (United States)

McHugh, Kieran

2010-01-01

Abstract Head and neck malignancy is rare in children. However, distinguishing malignant tumours from the more common and numerous benign causes of neck masses in childhood is crucial as many malignant conditions have an excellent prognosis with appropriate oncological management. Ultrasound, computed tomography and magnetic resonance imaging all have crucial roles in the diagnosis of head and neck malignancy in children and there is an emerging role for positron emission tomography, particularly in the management and follow-up of lymphoma. We describe the imaging appearances of the common malignant tumours arising in the extracranial head and neck in children, focusing on lymphoma, rhabdomyosarcoma and nasopharyngeal carcinoma. The clinical presentation and radiological appearances of benign tumours in the head and neck in children may overlap with those seen in malignant disease. We describe the imaging appearances of juvenile angiofibroma, vascular abnormalities involving the extracranial head and neck and cervical teratomas. Advances in both imaging techniques and cancer staging systems, many of the latter aimed at avoiding over-treatment and treatment-related complications, will lead to an increasingly central role for imaging in childhood head and neck cancer. PMID:20199940

Can magnetic resonance imaging differentiate undifferentiated arthritis?

DEFF Research Database (Denmark)

Østergaard, Mikkel; Duer, Anne; Hørslev-Petersen, K

2005-01-01

A high sensitivity for the detection of inflammatory and destructive changes in inflammatory joint diseases makes magnetic resonance imaging potentially useful for assigning specific diagnoses, such as rheumatoid arthritis and psoriatic arthritis in arthritides, that remain undifferentiated after...... conventional clinical, biochemical and radiographic examinations. With recent data as the starting point, the present paper describes the current knowledge on magnetic resonance imaging in the differential diagnosis of undifferentiated arthritis....

Ultra-Wideband Sensors for Improved Magnetic Resonance Imaging, Cardiovascular Monitoring and Tumour Diagnostics

Directory of Open Access Journals (Sweden)

Frank Seifert

2010-12-01

Full Text Available The specific advantages of ultra-wideband electromagnetic remote sensing (UWB radar make it a particularly attractive technique for biomedical applications. We partially review our activities in utilizing this novel approach for the benefit of high and ultra-high field magnetic resonance imaging (MRI and other applications, e.g., for intensive care medicine and biomedical research. We could show that our approach is beneficial for applications like motion tracking for high resolution brain imaging due to the non-contact acquisition of involuntary head motions with high spatial resolution, navigation for cardiac MRI due to our interpretation of the detected physiological mechanical contraction of the heart muscle and for MR safety, since we have investigated the influence of high static magnetic fields on myocardial mechanics. From our findings we could conclude, that UWB radar can serve as a navigator technique for high and ultra-high field magnetic resonance imaging and can be beneficial preserving the high resolution capability of this imaging modality. Furthermore it can potentially be used to support standard ECG analysis by complementary information where sole ECG analysis fails. Further analytical investigations have proven the feasibility of this method for intracranial displacements detection and the rendition of a tumour’s contrast agent based perfusion dynamic. Beside these analytical approaches we have carried out FDTD simulations of a complex arrangement mimicking the illumination of a human torso model incorporating the geometry of the antennas applied.

Ultra-wideband sensors for improved magnetic resonance imaging, cardiovascular monitoring and tumour diagnostics.

Science.gov (United States)

Thiel, Florian; Kosch, Olaf; Seifert, Frank

2010-01-01

The specific advantages of ultra-wideband electromagnetic remote sensing (UWB radar) make it a particularly attractive technique for biomedical applications. We partially review our activities in utilizing this novel approach for the benefit of high and ultra-high field magnetic resonance imaging (MRI) and other applications, e.g., for intensive care medicine and biomedical research. We could show that our approach is beneficial for applications like motion tracking for high resolution brain imaging due to the non-contact acquisition of involuntary head motions with high spatial resolution, navigation for cardiac MRI due to our interpretation of the detected physiological mechanical contraction of the heart muscle and for MR safety, since we have investigated the influence of high static magnetic fields on myocardial mechanics. From our findings we could conclude, that UWB radar can serve as a navigator technique for high and ultra-high field magnetic resonance imaging and can be beneficial preserving the high resolution capability of this imaging modality. Furthermore it can potentially be used to support standard ECG analysis by complementary information where sole ECG analysis fails. Further analytical investigations have proven the feasibility of this method for intracranial displacements detection and the rendition of a tumour's contrast agent based perfusion dynamic. Beside these analytical approaches we have carried out FDTD simulations of a complex arrangement mimicking the illumination of a human torso model incorporating the geometry of the antennas applied.

[Surface coils for magnetic-resonance images].

Science.gov (United States)

Rodríguez-González, Alfredo Odón; Amador-Baheza, Ricardo; Rojas-Jasso, Rafael; Barrios-Alvarez, Fernando Alejandro

2005-01-01

Since the introduction of magnetic resonance imaging in Mexico, the development of this important medical imaging technology has been almost non-existing in our country. The very first surface coil prototypes for clinical applications in magnetic resonance imaging has been developed at the Center of Research in Medical Imaging and Instrumentation of the Universidad Autónoma Metropolitana Iztapalapa (Metropolitan Autonomous University, Campus Iztapalapa). Two surface coil prototypes were built: a) a circular-shaped coil and b) a square-shaped coil for multiple regions of the body, such as heart, brain, knee, hands, and ankles. These coils were tested on the 1.5T imager of the ABC Hospital-Tacubaya, located in Mexico City. Brain images of healthy volunteers were obtained in different orientations: sagittal, coronal, and axial. Since images showed a good-enough clinical quality for diagnosis, it is fair to say that these coil prototypes can be used in the clinical environment, and with small modifications, they can be made compatible with almost any commercial scanner. This type of development can offer new alternatives for further collaboration between the research centers and the radiology community, in the search of new applications and developments of this imaging technique.

Amygdala Volumetry in Patients with Temporal Lobe Epilepsy and Normal Magnetic Resonance Imaging

International Nuclear Information System (INIS)

Singh, Paramdeep; Kaur, Rupinderjeet; Saggar, Kavita; Singh, Gagandeep; Aggarwal, Simmi

2016-01-01

It has been suggested that the pathophysiology of temporal lobe epilepsy may relate to abnormalities in various brain structures, including the amygdala. Patients with mesial temporal lobe epilepsy (MTLE) without MRI abnormalities (MTLE-NMRI) represent a challenge for diagnosis of the underlying abnormality and for presurgical evaluation. To date, however, only few studies have used quantitative structural Magnetic Resonance Imaging-based techniques to examine amygdalar pathology in these patients. Based on clinical examination, 24-hour video EEG recordings and MRI findings, 50 patients with EEG lateralized TLE and normal structural Magnetic Resonance Imaging results were included in this study. Volumetric magnetic resonance imaging (MRI) studies of the amygdalas and hippocampi were conducted in 50 non-epileptic controls (age 7–79 years) and 50 patients with MTLE with normal MRI on a 1.5-Tesla scanner. Visual assessment and amygdalar volumetry were performed on oblique coronal T2W and T1W MP-RAGE images respectively. The T2 relaxation times were measured using the 16-echo Carr-Purcell-Meiboom-Gill sequence (TE, 22–352). Volumetric data were normalized for variation in head size between individuals. Results were assessed by SSPS statistic program. Individual manual volumetric analysis confirmed statistically significant amygdala enlargement (AE) in eight (16%) patients. Overall, among all patients with AE and a defined epileptic focus, 7 had predominant increased volume ipsilateral to the epileptic focus. The T2 relaxometry demonstrated no hyperintense signal of the amygdala in any patient with significant AE. This paper presented AE in a few patients with TLE and normal MRI. These findings support the hypothesis that there might be a subgroup of patients with MTLE-NMRI in which the enlarged amygdala could be related to the epileptogenic process

Amygdala Volumetry in Patients with Temporal Lobe Epilepsy and Normal Magnetic Resonance Imaging

Science.gov (United States)

Singh, Paramdeep; Kaur, Rupinderjeet; Saggar, Kavita; Singh, Gagandeep; Aggarwal, Simmi

2016-01-01

Summary Background It has been suggested that the pathophysiology of temporal lobe epilepsy may relate to abnormalities in various brain structures, including the amygdala. Patients with mesial temporal lobe epilepsy (MTLE) without MRI abnormalities (MTLE-NMRI) represent a challenge for diagnosis of the underlying abnormality and for presurgical evaluation. To date, however, only few studies have used quantitative structural Magnetic Resonance Imaging-based techniques to examine amygdalar pathology in these patients. Material/Methods Based on clinical examination, 24-hour video EEG recordings and MRI findings, 50 patients with EEG lateralized TLE and normal structural Magnetic Resonance Imaging results were included in this study. Volumetric magnetic resonance imaging (MRI) studies of the amygdalas and hippocampi were conducted in 50 non-epileptic controls (age 7–79 years) and 50 patients with MTLE with normal MRI on a 1.5-Tesla scanner. Visual assessment and amygdalar volumetry were performed on oblique coronal T2W and T1W MP-RAGE images respectively. The T2 relaxation times were measured using the 16-echo Carr-Purcell-Meiboom-Gill sequence (TE, 22–352). Volumetric data were normalized for variation in head size between individuals. Results were assessed by SSPS statistic program. Results Individual manual volumetric analysis confirmed statistically significant amygdala enlargement (AE) in eight (16%) patients. Overall, among all patients with AE and a defined epileptic focus, 7 had predominant increased volume ipsilateral to the epileptic focus. The T2 relaxometry demonstrated no hyperintense signal of the amygdala in any patient with significant AE. Conclusions This paper presented AE in a few patients with TLE and normal MRI. These findings support the hypothesis that there might be a subgroup of patients with MTLE-NMRI in which the enlarged amygdala could be related to the epileptogenic process. PMID:27231493

Magnetic resonance imaging: hazard, risk and safety

International Nuclear Information System (INIS)

Narayan, Pradeep; Suri, S.; Singh, P.

2001-01-01

The hazard and risk associated with magnetic resonance imaging is a matter of concern. In 1982, the Food and Drug Administration (FDA), USA issued guidelines to Hospital's Investigational Review Board (IRBs) in 'Guidelines for Evaluating Electromagnetic Exposure Risks for Trials of Clinical Nuclear Magnetic Resonance (NMR)'. In 1997, the Berufsgenossenschaft (BG), professional association for precision engineering and electronics of Germany, in their preliminary proposal for safety limits extended their concerns on static magnetic field. Owing to both time varying and static magnetic fields applied in Magnetic Resonance Imaging (MRI) this became of immediate concern to user community to assess the potential hazard and risk associated with the NMR system

Magnetic resonance imaging of central nervous system haemorrhage

International Nuclear Information System (INIS)

Silberstein, M.; Hennessy, O.

1993-01-01

The variable magnetic resonance imaging appearances of central nervous system haemorrhage, both intra- and extra-axial, are described. These will vary with the type of image contrast (T1 or T2 weighting), the nature of the imaging sequence (spin-echo or gradient-echo) and the time from onset of haemorrhage. Magnetic resonance imaging is a useful technique for imaging haemorrhage in the central nervous system as it yields temporal information about haematoma development, and it is the only non-invasive means of imaging intraspinal haemorrhage. However, in the imaging of haematomas within 24 h of onset and in subarachnoid haemorrhage computed tomography is the investigation of choice. 13 refs., 6 figs

Magnetic resonance imaging of living systems by remote detection

Science.gov (United States)

Wemmer, David; Pines, Alexander; Bouchard, Louis; Xu, Shoujun; Harel, Elad; Budker, Dmitry; Lowery, Thomas; Ledbetter, Micah

2013-10-29

A novel approach to magnetic resonance imaging is disclosed. Blood flowing through a living system is prepolarized, and then encoded. The polarization can be achieved using permanent or superconducting magnets. The polarization may be carried out upstream of the region to be encoded or at the place of encoding. In the case of an MRI of a brain, polarization of flowing blood can be effected by placing a magnet over a section of the body such as the heart upstream of the head. Alternatively, polarization and encoding can be effected at the same location. Detection occurs at a remote location, using a separate detection device such as an optical atomic magnetometer, or an inductive Faraday coil. The detector may be placed on the surface of the skin next to a blood vessel such as a jugular vein carrying blood away from the encoded region.

Magnetic resonance imaging of chemistry.

Science.gov (United States)

Britton, Melanie M

2010-11-01

Magnetic resonance imaging (MRI) has long been recognized as one of the most important tools in medical diagnosis and research. However, MRI is also well placed to image chemical reactions and processes, determine the concentration of chemical species, and look at how chemistry couples with environmental factors, such as flow and heterogeneous media. This tutorial review will explain how magnetic resonance imaging works, reviewing its application in chemistry and its ability to directly visualise chemical processes. It will give information on what resolution and contrast are possible, and what chemical and physical parameters can be measured. It will provide examples of the use of MRI to study chemical systems, its application in chemical engineering and the identification of contrast agents for non-clinical applications. A number of studies are presented including investigation of chemical conversion and selectivity in fixed-bed reactors, temperature probes for catalyst pellets, ion mobility during tablet dissolution, solvent dynamics and ion transport in Nafion polymers and the formation of chemical waves and patterns.

Quantitative magnetic resonance micro-imaging methods for pharmaceutical research.

Science.gov (United States)

Mantle, M D

2011-09-30

The use of magnetic resonance imaging (MRI) as a tool in pharmaceutical research is now well established and the current literature covers a multitude of different pharmaceutically relevant research areas. This review focuses on the use of quantitative magnetic resonance micro-imaging techniques and how they have been exploited to extract information that is of direct relevance to the pharmaceutical industry. The article is divided into two main areas. The first half outlines the theoretical aspects of magnetic resonance and deals with basic magnetic resonance theory, the effects of nuclear spin-lattice (T(1)), spin-spin (T(2)) relaxation and molecular diffusion upon image quantitation, and discusses the applications of rapid magnetic resonance imaging techniques. In addition to the theory, the review aims to provide some practical guidelines for the pharmaceutical researcher with an interest in MRI as to which MRI pulse sequences/protocols should be used and when. The second half of the article reviews the recent advances and developments that have appeared in the literature concerning the use of quantitative micro-imaging methods to pharmaceutically relevant research. Copyright © 2010 Elsevier B.V. All rights reserved.

The clinical utility of reduced-distortion readout-segmented echo-planar imaging in the head and neck region: initial experience

Energy Technology Data Exchange (ETDEWEB)

Koyasu, Sho; Iima, Mami; Umeoka, Shigeaki; Morisawa, Nobuko; Togashi, Kaori [Kyoto University, Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Sakyo-Ku, Kyoto (Japan); Porter, David A. [Siemens AG, MED MR PLM AW Neurology, Allee am Roethelheimpark 2, Erlangen (Germany); Ito, Juichi [Kyoto University, Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Sakyo-Ku, Kyoto (Japan); Le Bihan, Denis [Kyoto University, Human Brain Research Center, Graduate School of Medicine, Sakyo-Ku, Kyoto (Japan); Neurospin, CEA-Saclay Center, Gif-sur-Yvette Cedex (France)

2014-12-15

To evaluate whether readout-segmented echo-planar imaging (RS-EPI) diffusion weighted image (DWI) can diminish image distortion in the head and neck area, compared with single-shot (SS)-EPI DWI. We conducted phantom and patient studies using 3 T magnetic resonance imaging (MRI) with a 16-channel coil. For the phantom study, we evaluated distortion and signal homogeneity in gel phantoms. For the patient study, 29 consecutive patients with clinically suspicious parotid lesions were prospectively enrolled. RS-EPI and SS-EPI DWI were evaluated by two independent readers for identification of organ/lesion and distortion, using semiquantitative scales and quantitative scores. Apparent diffusion coefficient (ADC) values and contrast-noise ratios of parotid tumours (if present; n = 15) were also compared. The phantom experiments showed that RS-EPI provided less distorted and more homogeneous ADC maps than SS-EPI. In the patient study, RS-EPI was found to provide significantly less distortion in almost all organs/lesions (p < 0.05), according to both semiquantitative scales and quantitative scores. There was no significant difference in ADC values and contrast-noise ratios between the two DWI techniques. The distortion in DWI was significantly reduced with RS-EPI in both phantom and patient studies. The RS-EPI technique provided more homogenous images than SS-EPI, and can potentially offer higher image quality in the head and neck area. (orig.)

Imaging Atherosclerosis with Hybrid Positron Emission Tomography/Magnetic Resonance Imaging

DEFF Research Database (Denmark)

Ripa, Rasmus Sejersten; Kjær, Andreas

2015-01-01

Noninvasive imaging of atherosclerosis could potentially move patient management towards individualized triage, treatment, and followup. The newly introduced combined positron emission tomography (PET) and magnetic resonance imaging (MRI) system could emerge as a key player in this context. Both...

Magnetic resonance imaging of generalised musculo-skeletal diseases

International Nuclear Information System (INIS)

Kaiser, W.A.; Schalke, B.C.G.

1989-01-01

The results presented are drawn from 320 examinations by NMR imaging of patients with various systemic muscle diseases (dystrophies, myositides, metabolic disorders), and are interpreted so as to explain the relevant characteristic distribution patterns of the degenerative processes in the femoral musculature as shown by the NMR images. Four basic patterns are presented according to the criteria homogeneous-heterogeneous and symmetric-asymmetric, and the diseases identified by the differential diagnostic evaluation are discussed. The optimum measuring conditions for magnetic resonance imaging of the musculature are given, and the specific magnetic resonance criteria of myositides, neurogenic myopathies, myofonous dystrophies, c.n. polio, morbus Pompe, familial hypokalemic paralysis, centronuclear mypathy, morbus Duchenne are explained. The significance of NMR imaging with regard to biopsy or therapy planning is discussed, and magnetic resonance examination is recommended to be applied prior to biopsy. (orig.) [de

PET/CT imaging in head and neck tumors

International Nuclear Information System (INIS)

Roedel, R.; Palmedo, H.; Reichmann, K.; Reinhardt, M.J.; Biersack, H.J.; Straehler-Pohl, H.J.; Jaeger, U.

2004-01-01

To evaluate the usefulness of combined PET/CT examinations for detection of malignant tumors and their metastases in head and neck oncology. 51 patients received whole body scans on a dual modality PET/CT system. CT was performed without i.v. contrast. The results were compared concerning the diagnostic impact of native CT scan on FDG-PET images and the additional value of fused imaging. From 153 lesions were 97 classified as malignant on CT and 136 on FDG/PET images, as suspicious for malignancy in 33 on CT and 7 on FDG-PET and as benign in 23 on CT and 10 on FDG-PET. With combined PET/CT all primary and recurrent tumors could be found, the detection rate in patients with unknown primary tumors was 45%. Compared to PET or CT alone the sensitivity, specifity and accuracy could be significantly improved by means of combined PET/CT. Fused PET/CT imaging with [F18]-FDG and native CT-scanning enables accurate diagnosis in 93% of lesions and 90% of patients with head and neck oncology. (orig.) [de

Anatomy and metabolism of the normal human brain studied by magnetic resonance at 1.5 Tesla

International Nuclear Information System (INIS)

Bottomley, P.A.; Hart, H.R. Jr.; Edelstein, W.A.; Schenck, J.F.; Smith, L.S.; Leue, W.M.; Mueller, O.M.; Redington, R.W.

1984-01-01

Proton magnetic resonance (MR) images were obtained of the human head in magnetic fields as high as 1.5 Tesla (T) using slotted resonator high radio-frequency (RF) detection coils. The images showed no RF field penetration problems and exhibited an 11 (+/-1)-fold improvement in signal-to-noise ratio over a .12-T imaging system. The first localized phosphorus 31, carbon 13, and proton MR chemical shift spectra recorded with surface coils from the head and body in the same instrument showed relative concentrations of phosphorus metabolites, triglycerides, and, when correlated with proton images, negligible lipid (-CH 2 -) signal from brain tissue on the time scale of the imaging experiment. Sugar phosphate and phosphodiester concentrations were significantly elevated in the head compared with muscle. This method should allow the combined assessment of anatomy, metabolism, and biochemistry in both the normal and diseased brain

Diffusion and Perfusion Magnetic Resonance Imaging:Fundamentals and Advances

OpenAIRE

Assili, Sanam

2016-01-01

Over the past few decades, magnetic resonance imaging has been utilized as a powerful imaging modality to evaluate the structure and function of various organs in the human body,such as the brain. Additionally, diffusion and perfusion MR imaging have been increasingly used in neurovascular clinical applications. In diffusion-weighted magnetic resonance imaging, the mobility of water molecules is explored in order to obtain information about the microscopic behavior of the tissues. In contrast...

Avascular necrosis of the femoral head: MR imaging with histologic correlation

Energy Technology Data Exchange (ETDEWEB)

Lee, Chae Guk; Cha, Seong Sook; Eun, Choong Ki; Yang, Young Il; Choi, Jang Seok [Pusan Paik Hospital, College of Medicine, Inje University, Busan (Korea, Republic of); Park, Dong Woo [College of Medicine, Hanyang University, Seoul (Korea, Republic of)

1995-07-15

To correlate MR findings with histologic findings in avascular necrosis (AVN) of the femoral head. MR findings was performed with 8 femoral head specimens using T1-and proton density weighted coronal SE sequences, and compared with contact radiography and histologic sections. In each specimen, necrotic zone in the superior portion of femoral head, repair zone located inferior to the necrotic zone, and rim adjacent to normal bone marrow could be defined. Necrotic zone showed high signal intensity on both T1-and proton density-weighted images in 3 cases which were composed of necrotic bone and marrow, and low signal intensity on both sequences in 2 cases which were composed of necrotic bone marrow with amorphous cellular debris. Mixed high and low signal intensities were seen in 3 cases. The repair zone showed low signal intensity on T1-weighted image and high signal intensity on proton density weighted image in 5 cases which were composed of thickened trabecular bone and mesenchymal tissue and also showed intermediate signal intensity on T1-weighted image and high signal intensity on proton density weighted image in 3 cases which were composed of osteoid, chondroid and undifferentiated mesenchymal cells. Rim shown as the low signal intensity on T1 weighted image in all cases was corresponded to viable thickened trabecular bone. MR imaging would be the best modality in the diagnosis of avascular necrosis of femoral head and when used in conjunction with degree and location of signal intensity, the prediction of histologic finding may be possible.

Avascular necrosis of the femoral head: MR imaging with histologic correlation

International Nuclear Information System (INIS)

Lee, Chae Guk; Cha, Seong Sook; Eun, Choong Ki; Yang, Young Il; Choi, Jang Seok; Park, Dong Woo

1995-01-01

To correlate MR findings with histologic findings in avascular necrosis (AVN) of the femoral head. MR findings was performed with 8 femoral head specimens using T1-and proton density weighted coronal SE sequences, and compared with contact radiography and histologic sections. In each specimen, necrotic zone in the superior portion of femoral head, repair zone located inferior to the necrotic zone, and rim adjacent to normal bone marrow could be defined. Necrotic zone showed high signal intensity on both T1-and proton density-weighted images in 3 cases which were composed of necrotic bone and marrow, and low signal intensity on both sequences in 2 cases which were composed of necrotic bone marrow with amorphous cellular debris. Mixed high and low signal intensities were seen in 3 cases. The repair zone showed low signal intensity on T1-weighted image and high signal intensity on proton density weighted image in 5 cases which were composed of thickened trabecular bone and mesenchymal tissue and also showed intermediate signal intensity on T1-weighted image and high signal intensity on proton density weighted image in 3 cases which were composed of osteoid, chondroid and undifferentiated mesenchymal cells. Rim shown as the low signal intensity on T1 weighted image in all cases was corresponded to viable thickened trabecular bone. MR imaging would be the best modality in the diagnosis of avascular necrosis of femoral head and when used in conjunction with degree and location of signal intensity, the prediction of histologic finding may be possible

Seizure Severity Is Correlated With Severity of Hypoxic-Ischemic Injury in Abusive Head Trauma.

Science.gov (United States)

Dingman, Andra L; Stence, Nicholas V; O'Neill, Brent R; Sillau, Stefan H; Chapman, Kevin E

2017-12-12

The objective of this study was to characterize hypoxic-ischemic injury and seizures in abusive head trauma. We performed a retrospective study of 58 children with moderate or severe traumatic brain injury due to abusive head trauma. Continuous electroencephalograms and magnetic resonance images were scored. Electrographic seizures (51.2%) and hypoxic-ischemic injury (77.4%) were common in our cohort. Younger age was associated with electrographic seizures (no seizures: median age 13.5 months, interquartile range five to 25 months, versus seizures: 4.5 months, interquartile range 3 to 9.5 months; P = 0.001). Severity of hypoxic-ischemic injury was also associated with seizures (no seizures: median injury score 1.0, interquartile range 0 to 3, versus seizures: 4.5, interquartile range 3 to 8; P = 0.01), but traumatic injury severity was not associated with seizures (no seizures: mean injury score 3.78 ± 1.68 versus seizures: mean injury score 3.83 ± 0.95, P = 0.89). There was a correlation between hypoxic-ischemic injury severity and seizure burden when controlling for patient age (r s =0.61, P interquartile range 0 to 0.23 on magnetic resonance imaging done within two days versus median restricted diffusion ratio 0.13, interquartile range 0.01 to 0.43 on magnetic resonance imaging done after two days, P = 0.03). Electrographic seizures are common in children with moderate to severe traumatic brain injury from abusive head trauma, and therefore children with suspected abusive head trauma should be monitored with continuous electroencephalogram. Severity of hypoxic-ischemic brain injury is correlated with severity of seizures, and evidence of hypoxic-ischemic injury on magnetic resonance imaging may evolve over time. Therefore children with a high seizure burden should be reimaged to evaluate for evolving hypoxic-ischemic injury. Published by Elsevier Inc.

A Comparative Evaluation of 3 Different Free-Form Deformable Image Registration and Contour Propagation Methods for Head and Neck MRI: The Case of Parotid Changes During Radiotherapy.

Science.gov (United States)

Broggi, Sara; Scalco, Elisa; Belli, Maria Luisa; Logghe, Gerlinde; Verellen, Dirk; Moriconi, Stefano; Chiara, Anna; Palmisano, Anna; Mellone, Renata; Fiorino, Claudio; Rizzo, Giovanna

2017-06-01

To validate and compare the deformable image registration and parotid contour propagation process for head and neck magnetic resonance imaging in patients treated with radiotherapy using 3 different approaches-the commercial MIM, the open-source Elastix software, and an optimized version of it. Twelve patients with head and neck cancer previously treated with radiotherapy were considered. Deformable image registration and parotid contour propagation were evaluated by considering the magnetic resonance images acquired before and after the end of the treatment. Deformable image registration, based on free-form deformation method, and contour propagation available on MIM were compared to Elastix. Two different contour propagation approaches were implemented for Elastix software, a conventional one (DIR_Trx) and an optimized homemade version, based on mesh deformation (DIR_Mesh). The accuracy of these 3 approaches was estimated by comparing propagated to manual contours in terms of average symmetric distance, maximum symmetric distance, Dice similarity coefficient, sensitivity, and inclusiveness. A good agreement was generally found between the manual contours and the propagated ones, without differences among the 3 methods; in few critical cases with complex deformations, DIR_Mesh proved to be more accurate, having the lowest values of average symmetric distance and maximum symmetric distance and the highest value of Dice similarity coefficient, although nonsignificant. The average propagation errors with respect to the reference contours are lower than the voxel diagonal (2 mm), and Dice similarity coefficient is around 0.8 for all 3 methods. The 3 free-form deformation approaches were not significantly different in terms of deformable image registration accuracy and can be safely adopted for the registration and parotid contour propagation during radiotherapy on magnetic resonance imaging. More optimized approaches (as DIR_Mesh) could be preferable for critical

Use of diffusion-weighted imaging (DWI) in PET/MRI for head and neck cancer evaluation

International Nuclear Information System (INIS)

Queiroz, Marcelo A.; Schulthess, Gustav von; Huellner, Martin; Kuhn, Felix; Veit-Haibach, Patrick; Huber, Gerhardt; Meerwein, Christian; Kollias, Spyros

2014-01-01

The purpose of this study was to analyze whether diffusion-weighted imaging (DWI) adds significant information to positron emission tomography/magnetic resonance imaging (PET/MRI) on lesion detection and characterization in head and neck cancers. Seventy patients with different head and neck cancers were enrolled in this prospective study. All patients underwent sequential contrast-enhanced (ce) PET/computed tomography (CT) and cePET/MRI using a tri-modality PET/CT-MR setup either for staging or re-staging. First, the DWI alone was evaluated, followed by the PET/MRI with conventional sequences, and in a third step, the PET/MRI with DWI was evaluated. McNemar's test was used to evaluate differences in the accuracy of PET/MRI with and without DWI compared to the standard of reference. One hundred eighty-eight (188) lesions were found, and of those, 118 (62.8 %) were malignant and 70 (37.2 %) were benign. PET/MRI without DWI had a higher accuracy in detecting malignant lesions than DWI alone (86.8 % vs. 60.6 %, p < 0.001). PET/MRI combined with DWI detected 120 concurrent lesions (89 malignant and 31 benign), PET/MRI alone identified 48 additional lesions (20 malignant and 28 benign), and DWI alone detected 20 different lesions (nine malignant and 11 benign). However, lesions detected on DWI did not change overall staging. SUV maximum and mean were significantly higher in malignant lesions than in benign lesions. DWI parameters between malignant and benign lesions were not statistically different. The use of DWI as part of PET/MRI to evaluate head and neck cancers does not provide remarkable information. Thus, the use of DWI might not be needed in clinical PET/MRI protocols for the staging or restaging of head and neck cancers. (orig.)

Image of а head of law-enforcement body on micro level (empirical experimentation

Directory of Open Access Journals (Sweden)

D. G. Perednya

2016-01-01

Full Text Available The article determines image of the head of law-enforcement body. Subjects and objects of image are described. Inhomogenuity of image is cleared up. Method of examination is shortly micro level described. It is talking about image, which is formed in mind of members of team of law-enforcement body, who are subordinated to object of image. State-of-the-art is illustrated, according to received data. Hypothesis about negative image of the head in mind of subordinates is disproved. It is shown contradiction of images in collective mind and social mind.

Contrast agents in magnetic resonance imaging

International Nuclear Information System (INIS)

Karadjian, V.

1987-01-01

The origine of nuclear magnetic resonance signal is reminded and different ways for contrast enhancement in magnetic resonance imaging are presented, especially, modifications of tissus relaxation times. Investigations have focused on development of agents incorporating either paramagnetic ions or stable free radicals. Pharmacological and toxicological aspects are developed. The diagnostic potential of these substances is illustrated by the example of gadolinium complexes [fr

Magnetic resonance imaging of the abdomen and pelvis

International Nuclear Information System (INIS)

Anon.

1989-01-01

Magnetic resonance imaging (MRI) of the abdomen presents greater inherent difficulties than other anatomic regions. However, new techniques now allow imaging comparable in quality to computed tomography (CT). Magnetic resonance imaging offers the advantages of greater tissue contrast, multiplanar imaging, and lack of ionizing radiation or risk of toxic reactions from iodinated contrast media. Its use remains limited by high cost, limited availability, lack of a bowel contrast agent, and long imaging time, which some patients cannot tolerate. In many areas of abdominal imaging, MRI is now comparable to CT, but because of the greater availability and lesser cost, CT remains the procedure of choice. Magnetic resonance imaging is more accurate for staging neoplasms of the liver, adrenal glands, kidneys, bladder, prostate, uterus, and cervix and may aid in diagnosis of hepatic, adrenal, and uterine masses. In selected patients, especially those in whom CT is inconclusive or those who cannot tolerate iodinated contrast material, MRI can provide valuable information. Development of faster scanning techniques and MRI contrast agents and wider availability will probably increase the usefulness of abdominal MRI. At this time, MRI complements other abdominal imaging procedures. In a small number of patients, however, it can provide unique information in a virtually risk-free manner

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... MRI) exam. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Catheter Angiography Magnetic Resonance, ...

Magnetic resonance imaging of ulnocarpal abutment syndrome

International Nuclear Information System (INIS)

Imaeda, Toshihiko; Nakamura, Ryogo; Shionoya, Kaori; Kato, Hitoshi; Makino, Naoki

1996-01-01

Ulnocarpal abutment syndrome (UAS) is the impingement between lunate and ulnar head. Twenty-two wrists of 19 patients were diagnosed as UAS arthroscopically after having undergone MRI examination. Ten wrists had MRI both before and after ulnar recession arthroplasty. Spin-echo pulse sequences were taken. T1-weighted and T2-weighted images were obtained. On T1-weighted images, the focal signal intensity of the ulnar part of the lunate was decreased in 18 wrists. On T2-weighted images, the focal signal intensity of the ulnar aspect of the lunate were from high to low in 18 wrists. There was focal and abnormal signal intensity of the triquetrum found in 10 wrists and was abnormal signal intensity of the ulnar head in two wrists. After the operation, on the T1-weighted image signal intensity of the lunate shifted from low through slightly low to iso. On the T2-weighted images it shifted from low to high or iso. Focal low signal intensity of the lunate on T1-weighted images is diagnostic of ulnocarpal abutment syndrome. The intensity of the signal from the lunate on T2-weighted images may indicate the severity of the disease. (author)

Magnetic resonance imaging investigation of the bone conduction implant – a pilot study at 1.5 Tesla

Directory of Open Access Journals (Sweden)

Fredén Jansson KJ

2015-10-01

Full Text Available Karl-Johan Fredén Jansson,1 Bo Håkansson,1 Sabine Reinfeldt,1 Cristina Rigato,1 Måns Eeg-Olofsson2 1Department of Signals and Systems, Chalmers University of Technology, 2Deptartment of Otorhinolaryngology Head and Neck Surgery, Sahlgrenska University Hospital, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden Purpose: The objective of this pilot study was to investigate if an active bone conduction implant (BCI used in an ongoing clinical study withstands magnetic resonance imaging (MRI of 1.5 Tesla. In particular, the MRI effects on maximum power output (MPO, total harmonic distortion (THD, and demagnetization were investigated. Implant activation and image artifacts were also evaluated.Methods and materials: One implant was placed on the head of a test person at the position corresponding to the normal position of an implanted BCI and applied with a static pressure using a bandage and scanned in a 1.5 Tesla MRI camera. Scanning was performed both with and without the implant, in three orthogonal planes, and for one spin-echo and one gradient-echo pulse sequence. Implant functionality was verified in-between the scans using an audio processor programmed to generate a sequence of tones when attached to the implant. Objective verification was also carried out by measuring MPO and THD on a skull simulator as well as retention force, before and after MRI.Results: It was found that the exposure of 1.5 Tesla MRI only had a minor effect on the MPO, ie, it decreased over all frequencies with an average of 1.1±2.1 dB. The THD remained unchanged above 300 Hz and was increased only at lower frequencies. The retention magnet was demagnetized by 5%. The maximum image artifacts reached a distance of 9 and 10 cm from the implant in the coronal plane for the spin-echo and the gradient-echo sequence, respectively. The test person reported no MRI induced sound from the implant.Conclusion: This pilot study indicates that the present BCI

MR imaging of solitary fibrous tumors in the head and neck

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Jeong [The Catholic University, Daejeon (Korea, Republic of); Lee, Ho Kyu; Shin, Ji Hoon; Lee, Jeong Hyun [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Seo, Jeong Jin [Chonnam National University Medical School, Kwangju (Korea, Republic of); Kim, Hyung Jim [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Jeong, Ae Kyung [University of Ulsan College of Medicine, Seoul (Korea, Republic of)

2005-09-15

Solitary fibrous tumor (SFT) is a very rare tumor. The purpose of this study is to determine the MR imaging features of SFT in the intracranial and extracranial head and neck regions. We retrospectively reviewed six MR images and two CT images of six histologically proven cases of SFT that occurred in four men and two women, and their ages ranged from 46 to 59 years. These imaging findings were correlated with the microscopic findings of their surgical specimens. Six SFTs arose in the meninges (the petrous ridge and the pituitary fossa), the parotid gland, the parapharyngeal space, the buccal space and the maxillary sinus. On the MR images, SFTs in the intracranial and extracranial head and neck regions were mostly isointense to the muscle on the T1-weighted images, they were hyperintense on the T2-weighted images and they all had intense enhancement. On the T1- and T2-weighted images, hypointense lines were observed within in five SFTs. On the CT images, the SFTs were hypodense to the muscle on the unenhanced images and they were heterogeneously enhanced on the contrast-enhanced images. An exceptional case of pituitary SFT was hypointense on the T2-weighted images and it was hyperdense on the unenhanced CT images, which correlated with the increased collagenous component and the cellular compactness. The imaging features of SFT are nonspecific; however, SFT should be included in the differential diagnosis of masses involving the intracranial and extracranial head and neck regions.

MR imaging of solitary fibrous tumors in the head and neck

International Nuclear Information System (INIS)

Kim, Hyun Jeong; Lee, Ho Kyu; Shin, Ji Hoon; Lee, Jeong Hyun; Seo, Jeong Jin; Kim, Hyung Jim; Jeong, Ae Kyung

2005-01-01

Solitary fibrous tumor (SFT) is a very rare tumor. The purpose of this study is to determine the MR imaging features of SFT in the intracranial and extracranial head and neck regions. We retrospectively reviewed six MR images and two CT images of six histologically proven cases of SFT that occurred in four men and two women, and their ages ranged from 46 to 59 years. These imaging findings were correlated with the microscopic findings of their surgical specimens. Six SFTs arose in the meninges (the petrous ridge and the pituitary fossa), the parotid gland, the parapharyngeal space, the buccal space and the maxillary sinus. On the MR images, SFTs in the intracranial and extracranial head and neck regions were mostly isointense to the muscle on the T1-weighted images, they were hyperintense on the T2-weighted images and they all had intense enhancement. On the T1- and T2-weighted images, hypointense lines were observed within in five SFTs. On the CT images, the SFTs were hypodense to the muscle on the unenhanced images and they were heterogeneously enhanced on the contrast-enhanced images. An exceptional case of pituitary SFT was hypointense on the T2-weighted images and it was hyperdense on the unenhanced CT images, which correlated with the increased collagenous component and the cellular compactness. The imaging features of SFT are nonspecific; however, SFT should be included in the differential diagnosis of masses involving the intracranial and extracranial head and neck regions

Magnetic resonance imaging in the cranio-cervical region

International Nuclear Information System (INIS)

Koschorek, F.; Jensen, H.P.; Terwey, B.

1987-01-01

Since the introduction of nuclear magnetic resonance imaging (NMR) in the neurosurgical and neurological diagnostic this new imaging modality has shown to be of high diagnostic value - especially in disease process of the cranio-vertebral junction. Other imaging moralities such as x-ray CT and myelography are of inferior quality as the images are degraded by bone artifacts and superposition of other structures. NMR can reveal many aspects of the cranio-vertebral region in a single examination without artifacts from surrounding structures. A further improvement of NMR is the introduction of para-magnetic agents, such as gadolinium-DTPA, as it increases the specifity by dynamic magnetic resonance imaging. The authors present a review of their clinical experience

Transcranial radiograph and magnetic resonance imaging in the evaluation of osseous changes of the temporomandibular joint

International Nuclear Information System (INIS)

Cho, Soo Beom; Koh, Kwang Joon

2002-01-01

To evaluate the diagnostic accuracy of transcranial radiographs and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) in the assessment of osseous changes of the condylar head and articular eminence. Osseous changes of the TMJ were evaluated in forty-three patients. Osseous changes of the condylar head and articular eminence were observed in 41 joints and 64 joints, respectively on transcranial radiographs, and 48 joints and 59 joints, respectively on MRI. The flattening, sclerosis, erosion, and osteophyte formation of the condylar heads were observed in 36.6%, 43.9%, 12.2%, and 7.3%, respectively on transcranial radiographs compared with 35.4%, 20.8%, 37.5%, and 6.3%, respectively on MRI. While, the flattening, sclerosis, and erosion of the articular eminences were observed in 26.6%, 67.2%, and 6.2%, respectively on transcranial radiographs compared with 32.2%, 59.3%, and 8.5%, respectively on MRI. There were no statistical differences between transcranial radiographs and MRI scans in the detection of osseous changes of the TMJ. However, MRI scans were superior to the transcranial radiographs in the detection of erosion of the condylar head (p<0.01).

Transcranial radiograph and magnetic resonance imaging in the evaluation of osseous changes of the temporomandibular joint

Energy Technology Data Exchange (ETDEWEB)

Cho, Soo Beom; Koh, Kwang Joon [School of Dentistry, Chonbuk National University, Chonju (Korea, Republic of)

2002-06-15

To evaluate the diagnostic accuracy of transcranial radiographs and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) in the assessment of osseous changes of the condylar head and articular eminence. Osseous changes of the TMJ were evaluated in forty-three patients. Osseous changes of the condylar head and articular eminence were observed in 41 joints and 64 joints, respectively on transcranial radiographs, and 48 joints and 59 joints, respectively on MRI. The flattening, sclerosis, erosion, and osteophyte formation of the condylar heads were observed in 36.6%, 43.9%, 12.2%, and 7.3%, respectively on transcranial radiographs compared with 35.4%, 20.8%, 37.5%, and 6.3%, respectively on MRI. While, the flattening, sclerosis, and erosion of the articular eminences were observed in 26.6%, 67.2%, and 6.2%, respectively on transcranial radiographs compared with 32.2%, 59.3%, and 8.5%, respectively on MRI. There were no statistical differences between transcranial radiographs and MRI scans in the detection of osseous changes of the TMJ. However, MRI scans were superior to the transcranial radiographs in the detection of erosion of the condylar head (p<0.01).

Improving the spatial accuracy in functional magnetic resonance imaging (fMRI) based on the blood oxygenation level dependent (BOLD) effect: benefits from parallel imaging and a 32-channel head array coil at 1.5 Tesla.

Science.gov (United States)

Fellner, C; Doenitz, C; Finkenzeller, T; Jung, E M; Rennert, J; Schlaier, J

2009-01-01

Geometric distortions and low spatial resolution are current limitations in functional magnetic resonance imaging (fMRI). The aim of this study was to evaluate if application of parallel imaging or significant reduction of voxel size in combination with a new 32-channel head array coil can reduce those drawbacks at 1.5 T for a simple hand motor task. Therefore, maximum t-values (tmax) in different regions of activation, time-dependent signal-to-noise ratios (SNR(t)) as well as distortions within the precentral gyrus were evaluated. Comparing fMRI with and without parallel imaging in 17 healthy subjects revealed significantly reduced geometric distortions in anterior-posterior direction. Using parallel imaging, tmax only showed a mild reduction (7-11%) although SNR(t) was significantly diminished (25%). In 7 healthy subjects high-resolution (2 x 2 x 2 mm3) fMRI was compared with standard fMRI (3 x 3 x 3 mm3) in a 32-channel coil and with high-resolution fMRI in a 12-channel coil. The new coil yielded a clear improvement for tmax (21-32%) and SNR(t) (51%) in comparison with the 12-channel coil. Geometric distortions were smaller due to the smaller voxel size. Therefore, the reduction in tmax (8-16%) and SNR(t) (52%) in the high-resolution experiment seems to be tolerable with this coil. In conclusion, parallel imaging is an alternative to reduce geometric distortions in fMRI at 1.5 T. Using a 32-channel coil, reduction of the voxel size might be the preferable way to improve spatial accuracy.

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance ...

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... magnetic resonance imaging (MRI) uses a powerful magnetic field, radio waves and a computer to produce detailed ... problems, medications, recent surgeries and allergies. The magnetic field is not harmful, but it may cause some ...

Subchondral insufficiency fractures of the femoral head

Energy Technology Data Exchange (ETDEWEB)

Davies, M.; Cassar-Pullicino, V.N. [Department of Radiology, Robert Jones and Agnes Hunt Orthopaedic and District Hospital, Oswestry, SY10 7AG, Shropshire (United Kingdom); Darby, A.J. [Department of Pathology, Robert Jones and Agnes Hunt Orthopaedic and District Hospital, Oswestry, SY10 7AG, Shropshire (United Kingdom)

2004-02-01

The aim of this study was to increase awareness of, and to show the variable clinical and radiological features of, subchondral insufficiency fractures of the femoral head. The clinical and radiological findings in 7 patients with subchondral insufficiency fractures of the femoral head were reviewed retrospectively. The diagnosis was confirmed histologically in 4 patients. Radiographs were performed in all patients, MRI in 5 and scintigraphy in 4 patients. Radiographs showed varying degrees of femoral head collapse in 4 patients. In the remaining 3 patients radiographs showed a normal femoral head, regional osteoporosis and focal sclerosis, respectively. Magnetic resonance imaging showed a low-signal band on T1- and T2-weighted images in the subchondral bone adjacent or parallel to the articular surface associated with bone marrow oedema. Scintigraphy showed increased uptake in the femoral head. Insufficiency fractures of the femoral head are easily overlooked or confused with avascular necrosis and, when there is significant joint destruction, osteoarthritis. Unsuspected insufficiency fracture of the femoral head can lead to significant and rapid loss of bone stock in osteoporotic patients waiting for arthroplasty for osteoarthritis. Increased awareness of this condition will hopefully lead to earlier diagnosis and a successful outcome of conservative treatment. (orig.)

Task-oriented lossy compression of magnetic resonance images

Science.gov (United States)

Anderson, Mark C.; Atkins, M. Stella; Vaisey, Jacques

1996-04-01

A new task-oriented image quality metric is used to quantify the effects of distortion introduced into magnetic resonance images by lossy compression. This metric measures the similarity between a radiologist's manual segmentation of pathological features in the original images and the automated segmentations performed on the original and compressed images. The images are compressed using a general wavelet-based lossy image compression technique, embedded zerotree coding, and segmented using a three-dimensional stochastic model-based tissue segmentation algorithm. The performance of the compression system is then enhanced by compressing different regions of the image volume at different bit rates, guided by prior knowledge about the location of important anatomical regions in the image. Application of the new system to magnetic resonance images is shown to produce compression results superior to the conventional methods, both subjectively and with respect to the segmentation similarity metric.

Neurological abnormalities in localized scleroderma of the face and head: a case series study for evaluation of imaging findings and clinical course.

Science.gov (United States)

Lis-Święty, Anna; Brzezińska-Wcisło, Ligia; Arasiewicz, Hubert

2017-09-01

Localized scleroderma (LoS) of the face and head is often associated with neurological manifestations and/or imaging abnormalities in the central nervous system (CNS). We present an analysis of 20 cases of LoS affecting the face and head. The CNS symptoms and/or abnormalities in high-resolution computed tomography (HRCT) and/or magnetic resonance imaging (MRI) were observed in 12 patients (60%). In addition to the mild and unspecific disorders (e.g. headaches), serious neurological complications probably in the course of vasculitis were revealed: epilepsy (in two patients), epilepsy and pyramidal sings (in one patient). Neurological disorders and LoS occurred at the same time (in three patients) or at the course of the disease (nine patients) and no later than 29 years since the onset of the disease. No link between neurological disorders and the LoS clinical morphology, immunological and other laboratory parameters has been established. CNS involvement is not correlated with the clinical course of the facial and head LoS and may occur years after the disease initial symptomatology. Imaging follow-up is not required if there is not any emerging neurological symptom. In some cases, however, both HRCT and MRI are useful for monitoring disease evolution and addressing therapeutic choices.

In Vivo Application of Proton-Electron Double-Resonance Imaging

Science.gov (United States)

Kishimoto, Shun; Krishna, Murali C.; Khramtsov, Valery V.; Utsumi, Hideo

2018-01-01

Abstract Significance: Proton-electron double-resonance imaging (PEDRI) employs electron paramagnetic resonance irradiation with low-field magnetic resonance imaging so that the electron spin polarization is transferred to nearby protons, resulting in higher signals. PEDRI provides information about free radical distribution and, indirectly, about the local microenvironment such as partial pressure of oxygen (pO2), tissue permeability, redox status, and acid-base balance. Recent Advances: Local acid-base balance can be imaged by exploiting the different resonance frequency of radical probes between R and RH+ forms. Redox status can also be imaged by using the loss of radical-related signal after reduction. These methods require optimized radical probes and pulse sequences. Critical Issues: High-power radio frequency irradiation is needed for optimum signal enhancement, which may be harmful to living tissue by unwanted heat deposition. Free radical probes differ depending on the purpose of PEDRI. Some probes are less effective for enhancing signal than others, which can reduce image quality. It is so far not possible to image endogenous radicals by PEDRI because low concentrations and broad line widths of the radicals lead to negligible signal enhancement. Future Directions: PEDRI has similarities with electron paramagnetic resonance imaging (EPRI) because both techniques observe the EPR signal, directly in the case of EPRI and indirectly with PEDRI. PEDRI provides information that is vital to research on homeostasis, development of diseases, or treatment responses in vivo. It is expected that the development of new EPR techniques will give insights into novel PEDRI applications and vice versa. Antioxid. Redox Signal. 28, 1345–1364. PMID:28990406

Tumor Metabolism and Perfusion in Head and Neck Squamous Cell Carcinoma: Pretreatment Multimodality Imaging With 1H Magnetic Resonance Spectroscopy, Dynamic Contrast-Enhanced MRI, and [18F]FDG-PET

International Nuclear Information System (INIS)

Jansen, Jacobus F.A.; Schöder, Heiko; Lee, Nancy Y.; Stambuk, Hilda E.; Wang Ya; Fury, Matthew G.; Patel, Senehal G.; Pfister, David G.; Shah, Jatin P.; Koutcher, Jason A.; Shukla-Dave, Amita

2012-01-01

Purpose: To correlate proton magnetic resonance spectroscopy ( 1 H-MRS), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and 18 F-labeled fluorodeoxyglucose positron emission tomography ([ 18 F]FDG PET) of nodal metastases in patients with head and neck squamous cell carcinoma (HNSCC) for assessment of tumor biology. Additionally, pretreatment multimodality imaging was evaluated for its efficacy in predicting short-term response to treatment. Methods and Materials: Metastatic neck nodes were imaged with 1 H-MRS, DCE-MRI, and [ 18 F]FDG PET in 16 patients with newly diagnosed HNSCC, before treatment. Short-term patient radiological response was evaluated at 3 to 4 months. Correlations among 1 H-MRS (choline concentration relative to water [Cho/W]), DCE-MRI (volume transfer constant [K trans ]; volume fraction of the extravascular extracellular space [v e ]; and redistribution rate constant [k ep ]), and [ 18 F]FDG PET (standard uptake value [SUV] and total lesion glycolysis [TLG]) were calculated using nonparametric Spearman rank correlation. To predict short-term responses, logistic regression analysis was performed. Results: A significant positive correlation was found between Cho/W and TLG (ρ = 0.599; p = 0.031). Cho/W correlated negatively with heterogeneity measures of standard deviation std(v e ) (ρ = −0.691; p = 0.004) and std(k ep ) (ρ = −0.704; p = 0.003). Maximum SUV (SUVmax) values correlated strongly with MRI tumor volume (ρ = 0.643; p = 0.007). Logistic regression indicated that std(K trans ) and SUVmean were significant predictors of short-term response (p 1 H-MRS, DCE-MRI, and [ 18 F]FDG PET is feasible in HNSCC patients with nodal metastases. Additionally, combined DCE-MRI and [ 18 F]FDG PET parameters were predictive of short-term response to treatment.

Waveguide volume probe for magnetic resonance imaging and spectroscopy

DEFF Research Database (Denmark)

2015-01-01

The present disclosure relates to a probe for use within the field of nuclear magnetic resonance, such as magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS)). One embodiment relates to an RF probe for magnetic resonance imaging and/or spectroscopy comprising a conductive...... non-magnetic hollow waveguide having an internal volume and at least one open end, one or more capacitors and at least a first conductive non-magnetic wire, wherein said first conductive wire connects at least one of said one or more capacitors to opposite walls of one open end of the waveguide...

Reducing Field Distortion in Magnetic Resonance Imaging

Science.gov (United States)

Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

2010-01-01

A concept for a magnetic resonance imaging (MRI) system that would utilize a relatively weak magnetic field provides for several design features that differ significantly from the corresponding features of conventional MRI systems. Notable among these features are a magnetic-field configuration that reduces (relative to the conventional configuration) distortion and blurring of the image, the use of a superconducting quantum interference device (SQUID) magnetometer as the detector, and an imaging procedure suited for the unconventional field configuration and sensor. In a typical application of MRI, a radio-frequency pulse is used to excite precession of the magnetic moments of protons in an applied magnetic field, and the decaying precession is detected for a short time following the pulse. The precession occurs at a resonance frequency proportional to the strengths of the magnetic field and the proton magnetic moment. The magnetic field is configured to vary with position in a known way; hence, by virtue of the aforesaid proportionality, the resonance frequency varies with position in a known way. In other words, position is encoded as resonance frequency. MRI using magnetic fields weaker than those of conventional MRI offers several advantages, including cheaper and smaller equipment, greater compatibility with metallic objects, and higher image quality because of low susceptibility distortion and enhanced spin-lattice-relaxation- time contrast. SQUID MRI is being developed into a practical MRI method for applied magnetic flux densities of the order of only 100 T

Titanium in Magnetic Resonance imaging of Head and Neck Area

Czech Academy of Sciences Publication Activity Database

Hubálková, H.; Starčuk, Zenon; Linetskiy, I.; Mazánek, J.; Dostálová, T.

2005-01-01

Roč. 55, Suppl. (2005), s. 56 ISSN 0033-1783. [Annual Conference of the European Prosthodontic Association /29./ and Annual Conference of the Polish Prosthodontic Association /23./ (EPA 2005). 01.09.2005-03.09.2005, Poznan] R&D Projects: GA MZd(CZ) NR8110 Keywords : magnetic resonance * artifacts * titanium * dental materials * dental implants Subject RIV: FS - Medical Facilities ; Equipment

Nuclear magnetic resonance spectroscopy and imaging

International Nuclear Information System (INIS)

Jiang Weiping; Wang Qi; Zhou Xin

2013-01-01

This paper briefly introduces the basic principle of nuclear magnetic resonance (NMR). Protein's structures and functions and dynamics studied by liquid NMR are elaborated; methods for enhancing the resolution of solid state NMR and its applications are discussed; the principle of magnetic resonance imaging (MRI) is interpreted, and applications in different aspects are reviewed. Finally, the progress of NMR is commented. (authors)

Lymphoma of uterine cervix: magnetic resonance imaging findings

Energy Technology Data Exchange (ETDEWEB)

Kanaan, Daniel; Constantino, Carolina Pesce Lamas; Souza, Rodrigo Canellas de, E-mail: daniel.kanaan@hotmail.com [Department of Radiology, Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Parente, Daniella Braz [Instituto D' Or de Pesquisa e Ensino, Rio de Janeiro, RJ (Brazil)

2012-05-15

Lymphoma of the cervix is a rare disease. About 1.0% to 1.5% of extranodal lymphomas originates in the female genital tract. The clinical presentation of this condition is nonspecific and magnetic resonance imaging is important for diagnostic elucidation. The present report describes the case of a 80-year-old patient with lumbar pain, whose magnetic resonance imaging showed a large uterine mass. The final diagnosis was lymphoma. (author)

Nuclear magnetic resonance imaging of the head

International Nuclear Information System (INIS)

Uhlenbrock, D.; Lukas, P.; Sehlen, S.; Weidenmaier, W.; Steiner, G.

1990-01-01

This pocket book is a clearly arranged and amply illustrated textbook presenting practice-oriented information for readers who seek a concise but nevertheless complete introduction to the complex subject: The technical aspects and physical principles are explained, and a catalogue of reference data and principles for image interpretation is given. The specific information refers to the clinical neuroanatomy and neuropathology of the most frequent lesions (intracranial tumors; cerebrovascular, inflammatory and degenerative lesions; hydrocephalus, multiple sclerosis, traumata, post-surgical changes, radiation effects). There also is a chapter discussing neuropediatric lesions. (orig.) With 257 ill. covering 401 figs., 15 tabs [de

Pocket atlas of cranial magnetic resonance imaging

International Nuclear Information System (INIS)

Haughton, V.M.; Daniels, D.L.

1986-01-01

This atlas illustrates normal cerebral anatomy in magnetic resonance images. From their studies in cerebral anatomy utilizing cryomicrotome and other techniques, the authors selected more than 100 high-resolution images that represent the most clinically useful scans

Children's (Pediatric) Magnetic Resonance Imaging

Medline Plus

Full Text Available ... Magnetic Resonance Imaging Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ... links: For the convenience of our users, RadiologyInfo .org provides links to relevant websites. RadiologyInfo.org , ACR ...

Is the spatial distribution of brain lesions associated with closed-head injury predictive of subsequent development of attention-deficit/hyperactivity disorder? Analysis with brain-image database

Science.gov (United States)

Herskovits, E. H.; Megalooikonomou, V.; Davatzikos, C.; Chen, A.; Bryan, R. N.; Gerring, J. P.

1999-01-01

PURPOSE: To determine whether there is an association between the spatial distribution of lesions detected at magnetic resonance (MR) imaging of the brain in children after closed-head injury and the development of secondary attention-deficit/hyperactivity disorder (ADHD). MATERIALS AND METHODS: Data obtained from 76 children without prior history of ADHD were analyzed. MR images were obtained 3 months after closed-head injury. After manual delineation of lesions, images were registered to the Talairach coordinate system. For each subject, registered images and secondary ADHD status were integrated into a brain-image database, which contains depiction (visualization) and statistical analysis software. Using this database, we assessed visually the spatial distributions of lesions and performed statistical analysis of image and clinical variables. RESULTS: Of the 76 children, 15 developed secondary ADHD. Depiction of the data suggested that children who developed secondary ADHD had more lesions in the right putamen than children who did not develop secondary ADHD; this impression was confirmed statistically. After Bonferroni correction, we could not demonstrate significant differences between secondary ADHD status and lesion burdens for the right caudate nucleus or the right globus pallidus. CONCLUSION: Closed-head injury-induced lesions in the right putamen in children are associated with subsequent development of secondary ADHD. Depiction software is useful in guiding statistical analysis of image data.

Parallel magnetic resonance imaging

International Nuclear Information System (INIS)

Larkman, David J; Nunes, Rita G

2007-01-01

Parallel imaging has been the single biggest innovation in magnetic resonance imaging in the last decade. The use of multiple receiver coils to augment the time consuming Fourier encoding has reduced acquisition times significantly. This increase in speed comes at a time when other approaches to acquisition time reduction were reaching engineering and human limits. A brief summary of spatial encoding in MRI is followed by an introduction to the problem parallel imaging is designed to solve. There are a large number of parallel reconstruction algorithms; this article reviews a cross-section, SENSE, SMASH, g-SMASH and GRAPPA, selected to demonstrate the different approaches. Theoretical (the g-factor) and practical (coil design) limits to acquisition speed are reviewed. The practical implementation of parallel imaging is also discussed, in particular coil calibration. How to recognize potential failure modes and their associated artefacts are shown. Well-established applications including angiography, cardiac imaging and applications using echo planar imaging are reviewed and we discuss what makes a good application for parallel imaging. Finally, active research areas where parallel imaging is being used to improve data quality by repairing artefacted images are also reviewed. (invited topical review)

Magnetic resonance imaging findings in patients with Hallervorden-Spatz syndrome

International Nuclear Information System (INIS)

Nomura, Cesar Higa; Lima, Eduardo Carneiro; Cerri, Giovanni Guido; Leite, Claudia da Costa; Rosemberg, Sergio

2003-01-01

The objective of this study was to review the magnetic resonance imaging findings in patients with Hallervorden-Spatz syndrome. We evaluated eight patients with Hallervorden-Spatz syndrome using magnetic resonance imaging. The protocol included at least sagittal and axial T1-weighted images and axial and coronal T2-weighted images. Intravenous gadolinium was administered in a dose of 0.1 mmol/kg. Post-enhanced images were obtained at least in the axial and coronal planes. The results were: all patients presented a bilateral and symmetrical 'tiger-eye signal' on T2-weighted images, corresponding to central hyperintensity and peripheral hypointensity in the globi pallidus. FLAIR and diffusion images showed similar abnormalities. There was no gadolinium enhancement in any of the cases. We concluded that magnetic resonance imaging findings in patients with Hallervorden-Spatz syndrome are very typical and allow the diagnosis of the disease. (author)

Resonant Mode Reduction in Radiofrequency Volume Coils for Ultrahigh Field Magnetic Resonance Imaging

Directory of Open Access Journals (Sweden)

Xiaoliang Zhang

2011-07-01

Full Text Available In a multimodal volume coil, only one mode can generate homogeneous Radiofrequency (RF field for Magnetic Resonance Imaging. The existence of other modes may increase the volume coil design difficulties and potentially decreases coil performance. In this study, we introduce common-mode resonator technique to high and ultrahigh field volume coil designs to reduce the resonant mode while maintain the homogeneity of the RF field. To investigate the design method, the common-mode resonator was realized by using a microstrip line which was split along the central to become a pair of parallel transmission lines within which common-mode currents exist. Eight common-mode resonators were placed equidistantly along the circumference of a low loss dielectric cylinder to form a volume coil. Theoretical analysis and comparison between the 16-strut common-mode volume coil and a conventional 16-strut volume coil in terms of RF field homogeneity and efficiency was performed using Finite-Difference Time-Domain (FDTD method at 298.2 MHz. MR imaging experiments were performed by using a prototype of the common-mode volume coil on a whole body 7 Tesla scanner. FDTD simulation results showed the reduced number of resonant modes of the common-mode volume coil over the conventional volume coil, while the RF field homogeneity of the two type volume coils was kept at the same level. MR imaging of a water phantom and a kiwi fruit showing the feasibility of the proposed method for simplifying the volume coil design is also presented.

Impact of the Parameter Variation on the Image Blurring in 3 T Magnetic Resonance Imaging: A Phantom Study

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Woo; Lee, Sang Hoon; Kim, Nam Kug; Cho, Kyung Sik; Lee, Jin Seong [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

2013-04-15

To evaluate the effects of the key imaging-parameter alterations on the four MR sequences in a phantom study. Magnetic resonance (MR) imaging was performed on a MR phantom with an 8-channel head coil by using a 3 T MR system. The images were obtained in the axial plane on four MR sequences [T1-weighted, T2-weighted, Proton-density, and 3 dimensional (3D) fast spin echo (FSE)] with controlled variations in the following key parameters: 1) echo train length (ETL), 2) repetition time (TR), and 3) echo time (TE). The image blurring was determined by the degree of the gradient angle; i.e., the blurring increased as the gradient angle decreases. The increasing ETL was observed to cause an increase in the image blurring on all pulse sequences with a statistical significance (p = 0.004) on the 3D FSE. Increasing the TR appeared to have no effect except a statistically significant decrease on the T1-weighted images (p = 0.011). Increasing TE showed no effect on the T1-weighted images (p = 0.932); however, it caused an increase of blurring on the proton density images (p = 0.016) as well as the T2-weighted images (p < 0.001), and a decrease on the 3D FSE (p = 0.001). To reduce the image blurring, short ETL and long TE for 3D FSE, long TR for T1-weighted images and short TE for proton-density and T2-weighted images should be applied.

Three-dimensional display of femoral head cartilage thickness maps from MR images

International Nuclear Information System (INIS)

Rubin, R.A.; Dolecki, M.; Rubash, H.E.; Thaete, F.L.; Hernden, J.H.

1990-01-01

This paper reports on the development of methods for three-dimensional display and analysis of the articular cartilage of the hip from MR images. Cadaveric femoral head specimens were images with three-dimensional GRASS MR imaging. Data were analyzed on a SUN workstation with original software, the ANALYZE package from Richard Robb's Biomedical Research Group at the Mayo Clinic, and SUN's Voxvu program. The articular cartilage was isolated by manually segmenting images. An original computer ray tracing method measured the cartilage thickness radially and produced movies of a rotating femoral head, displaying brightness proportional to cartilage thickness

Unusual Presentation of Popliteal Cyst on Magnetic Resonance Imaging

Directory of Open Access Journals (Sweden)

Tsuyoshi Ohishi

2016-01-01

Full Text Available Popliteal cyst commonly presents as an ellipsoid mass with uniform low signal intensity on T1-weighted magnetic resonance images and high signal intensity on T2-weighted images. Here, we describe a popliteal cyst with unusual appearance on magnetic resonance imaging, including heterogeneous intermediate signal intensity on T2-weighted images. Arthroscopic cyst decompression revealed that the cyst was filled with necrotic synovial villi, indicative of rheumatoid arthritis. Arthroscopic enlargement of unidirectional valvular slits with synovectomy was useful for the final diagnosis and treatment.

Free radicals imaged in vivo in the rat by using proton-electron double-resonance imaging

International Nuclear Information System (INIS)

Lurie, D.J.; Nicholson, Ian; Foster, M.A.; Mallard, J.R.

1990-01-01

A new technique called proton-electron double-resonance imaging is described for imaging free radicals in aqueous samples. The method is a combination of proton NMR imaging with nuclear electron double resonance. The results of using this technique to image free radicals in vivo in the rat are presented. Rats were injected intravenously with a nitroxide free radical solution and a series of images was obtained from which the clearance of the free radical through the liver and kidneys could be observed. (author)

Magnetic resonance angiography of the extracranial carotid and vertebral arteries

International Nuclear Information System (INIS)

Akimura, Tatsuo; Saito, Kenichi; Nakayama, Hisato; Kashiwagi, Shiro; Kato, Shoichi; Ito, Haruhide.

1994-01-01

To evaluate the contribution of magnetic resonance angiography (MRA) in the screening study of the extracranial carotid and vertebral arteries using the conventional head and neck coils, 500 consecutive MRAs of the cervical vessels were performed using 1.5 tesla magnetic resonance unit with circularly polarized head coil. The 5 cm-thick imaging plane was placed in coronal fashion including both carotid and vertebral arteries. The imaging sequence was three-dimensional (3D) fast imaging with steady precession (FISP). In 10 patients with failed head coil examination, 10 patients with possible carotid and vertebral diseases and 10 volunteers, the extracranial carotid and vertebral arteries were examined with the Helmholtz neck coil. Both 3D- and 2D-FISP were performed in each case. The imaging plane was placed in oblique sagittal fashion. In 458 out of 500 cases (91.6%), the extracranial carotid and vertebral arteries were successfully depicted using head coil. In 20 patients with high shoulders, the carotid bifurcations were out of range of the head coil. In these cases, carotid bifurcations and the origins of the carotid and vertebral arteries were successfully revealed using a neck coil. To evaluate the stenotic lesions and tortuous vessels, 2D-FISP sequence seemed to be more suitable than 3D-FISP. Compared with conventional angiography, MRA caused overestimation of the degree of stenotic lesions. For screening examination of the extracranial carotid and vertebral arteries, most cases can be evaluated only with the conventional head coil. If depiction of the carotid bifurcation fails and the examination of carotids or vertebrals down to the aortic arch is needed, neck coil examination is required. (author)

Nuclear magnetic resonance imaging

International Nuclear Information System (INIS)

1983-06-01

This report summarises the aspects of nuclear magnetic resonance imaging (NMRI) considered by the National Health Technology Advisory Panel and makes recommendations on its introduction in Australia with particular regard to the need for thorough evaluation of its cost effectiveness. Topics covered are: principles of the technique, equipment required, installation, costs, reliability, performance parameters, clinical indications, training and staff requirements, and safety considerations

Magnetic resonance imaging of vulnerable atherosclerotic plaques: current imaging strategies and molecular imaging probes

NARCIS (Netherlands)

Briley-Saebo, Karen C.; Mulder, Willem J. M.; Mani, Venkatesh; Hyafil, Fabien; Amirbekian, Vardan; Aguinaldo, Juan Gilberto S.; Fisher, Edward A.; Fayad, Zahi A.

2007-01-01

The vulnerability or destabilization of atherosclerotic plaques has been directly linked to plaque composition. Imaging modalities, such as magnetic resonance (MR) imaging, that allow for evaluation of plaque composition at a cellular and molecular level, could further improve the detection of

Nuclear magnetic resonance

International Nuclear Information System (INIS)

Cremin, B.J.

1981-01-01

Recent advances in diagnostic imaging, have been the medical application of nuclear magnetic resonance (NMR). It's been used to study the structure of various compounds in chemistry and physics, and in the mid-1970 to produce images of rabbits and eventually of the human hand and head. The images are produced by making use of the nuclear magnetization of the hydrogen ion, or proton, that is present in biological material to record the density distribution of protons in cellular water and lipids. An exploration of the end-results of complicated free induction decay signals, that have been digitized and frequency-analysed by mathematical computerized techniques to produce an image of tissue density, is given. At present NMR produces images comparable to those of early computed tomography

Structural magnetic resonance imaging in epilepsy

Energy Technology Data Exchange (ETDEWEB)

Deblaere, Karel [Ghent University Hospital, Department of Neuroradiology, Ghent (Belgium); Ghent University Hospital, MR Department - 1K12, Ghent (Belgium); Achten, Eric [Ghent University Hospital, Department of Neuroradiology, Ghent (Belgium)

2008-01-15

Because of its sensitivity and high tissue contrast, magnetic resonance imaging (MRI) is the technique of choice for structural imaging in epilepsy. In this review the effect of using optimised scanning protocols and the use of high field MR systems on detection sensitivity is discussed. Also, the clinical relevance of adequate imaging in patients with focal epilepsy is highlighted. The most frequently encountered MRI findings in epilepsy are reported and their imaging characteristics depicted. Imaging focus will be on the diagnosis of hippocampal sclerosis and malformations of cortical development, two major causes of medically intractable focal epilepsy. (orig.)

Structural magnetic resonance imaging in epilepsy

International Nuclear Information System (INIS)

Deblaere, Karel; Achten, Eric

2008-01-01

Because of its sensitivity and high tissue contrast, magnetic resonance imaging (MRI) is the technique of choice for structural imaging in epilepsy. In this review the effect of using optimised scanning protocols and the use of high field MR systems on detection sensitivity is discussed. Also, the clinical relevance of adequate imaging in patients with focal epilepsy is highlighted. The most frequently encountered MRI findings in epilepsy are reported and their imaging characteristics depicted. Imaging focus will be on the diagnosis of hippocampal sclerosis and malformations of cortical development, two major causes of medically intractable focal epilepsy. (orig.)

Magnetic resonance imaging and image analysis for assessment of HPMC matrix tablets structural evolution in USP Apparatus 4.

Science.gov (United States)

Kulinowski, Piotr; Dorożyński, Przemysław; Młynarczyk, Anna; Węglarz, Władysław P

2011-05-01

The purpose of the study was to present a methodology for the processing of Magnetic Resonance Imaging (MRI) data for the quantification of the dosage form matrix evolution during drug dissolution. The results of the study were verified by comparison with other approaches presented in literature. A commercially available, HPMC-based quetiapine fumarate tablet was studied with a 4.7T MR system. Imaging was performed inside an MRI probe-head coupled with a flow-through cell for 12 h in circulating water. The images were segmented into three regions using threshold-based segmentation algorithms due to trimodal structure of the image intensity histograms. Temporal evolution of dry glassy, swollen glassy and gel regions was monitored. The characteristic features were observed: initial high expansion rate of the swollen glassy and gel layers due to initial water uptake, dry glassy core disappearance and maximum area of swollen glassy region at 4 h, and subsequent gel layer thickness increase at the expense of swollen glassy layer. The temporal evolution of an HPMC-based tablet by means of noninvasive MRI integrated with USP Apparatus 4 was found to be consistent with both the theoretical model based on polymer disentanglement concentration and experimental VIS/FTIR studies.

Meniscal configuration using magnetic resonance imaging; Configuracao meniscal pela ressonancia magnetica

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Arthur da Rocha C.; Turrini, Elisabete; Karoauk, Teresa C.C.; Lederman, Henrique M. [Escola Paulista de Medicina, Sao Paulo, SP (Brazil). Dept. de Diagnostico por Imagem

1997-04-01

The authors present a review of the normal meniscal configuration and correlation with anatomic specimens. The images were obtained by magnetic resonance imaging. The images were obtained by magnetic resonance imaging. The authors emphasize the importance of knowing the relationship between the meniscus and the adjacent anatomic structures. (author) 31 refs., 10 figs., tabs.

Magnetic resonance imaging of the normal equine digit and metacarpophalangeal joint

International Nuclear Information System (INIS)

Park, R.D.; Nelson, T.R.; Hoopes, P.J.

1987-01-01

Magnetic resonance (MR) images were made in sagittal and transverse planes through the metacarpophalangeal joint and digit of a horse. The images accurately depicted gross anatomic structures in the leg. Soft tissue structures were defined as separate entities on the images. Histologic variation in tissues correlated with signal intensity differences on the MR images. Magnetic resonance imaging appears to be a promising imaging modality for evaluating musculoskeletal structures in equine limbs

Magnetic resonance spectroscopy as an imaging method

International Nuclear Information System (INIS)

Bomsdorf, H.; Imme, M.; Jensen, D.; Kunz, D.; Menhardt, W.; Ottenberg, K.; Roeschmann, P.; Schmidt, K.H.; Tschendel, O.; Wieland, J.

1990-01-01

An experimental Magnetic Resonance (MR) system with 4 tesla flux density was set up. For that purpose a data acquisition system and RF coils for resonance frequencies up to 170 MHz were developed. Methods for image guided spectroscopy as well as spectroscopic imaging focussing on the nuclei 1 H and 13 C were developed and tested on volunteers and selected patients. The advantages of the high field strength with respect to spectroscopic studies were demonstrated. Developments of a new fast imaging technique for the acquisition of scout images as well as a method for mapping and displaying the magnetic field inhomogeneity in-vivo represent contributions to the optimisation of the experimental procedure in spectroscopic studies. Investigations on the interaction of RF radiation with the exposed tissue allowed conclusions regarding the applicability of MR methods at high field strengths. Methods for display and processing of multi-dimensional spectroscopic imaging data sets were developed and existing methods for real-time image synthesis were extended. Results achieved in the field of computer aided analysis of MR images comprised new techniques for image background detection, contour detection and automatic image interpretation as well as knowledge bases for textural representation of medical knowledge for diagnosis. (orig.) With 82 refs., 3 tabs., 75 figs [de

Clinical magnetic resonance: imaging and spectroscopy

International Nuclear Information System (INIS)

Andrew, E.R.; Bydder, Graeme; Griffiths, John; Iles, Richard; Styles, Peter

1990-01-01

This book begins with a readable, comprehensive but non-mathematical introduction to the basic underlying principles of magnetic resonance. Further chapters include information on the theory and principles of MRI and MRS, the interpretation of MR images, the clinical applications and scope of MRI and MRS, practical aspects of spectroscopy and magnetic resonance, and also the practical problems associated with the siting, safety and operation of large MRI and MRS equipment. (author)

Functional magnetic resonance imaging to determine hemispheric language dominance prior to carotid endarterectomy.

Science.gov (United States)

Smits, M; Wieberdink, R G; Bakker, S L M; Dippel, D W J

2011-04-01

We describe a left-handed patient with transient aphasia and bilateral carotid stenosis. Computed tomography (CT) arteriography showed a 90% stenosis of the right and 30% stenosis of the left internal carotid artery. Head CT and magnetic resonance imaging (MRI) of the brain showed no recent ischemic changes. As only the symptomatic side would require surgical intervention, and because hemispheric dominance for language in left-handed patients may be either left or right sided, a preoperative assessment of hemispheric dominance was required. We used functional MRI to determine hemispheric dominance for language and hence to establish the indication for carotid endarterectomy surgery. Functional MRI demonstrated right hemispheric dominance for language and right-sided carotid endarterectomy was performed. We propose that the clinical use of functional MRI as a noninvasive imaging technique for the assessment of hemispheric language dominance may be extended to the assessment of hemispheric language dominance prior to carotid endarterectomy. Copyright © 2010 by the American Society of Neuroimaging.

Far-field superresolution by imaging of resonance scattering

KAUST Repository

Schuster, Gerard T.; Huang, Y.

2014-01-01

We show that superresolution imaging in the far-field region of the sources and receivers is theoretically and practically possible if migration of resonant multiples is employed. A resonant multiple is one that bounces back and forth between two

Head and neck imaging with MDCT

International Nuclear Information System (INIS)

Imhof, H.; Czerny, Chr.; Dirisamer, A.

2003-01-01

Multi-slice CT (MDCT) is rapidly becoming the new standard in radiological imaging. Although its advantages in cardiovascular, thoracic and abdominal imaging are evident, the extent of its usefulness for imaging the head and neck has yet to be clarified. Because of the shorter examination time motion artifacts are reduced, phonation-studies are possible. Due to the thin-slicing and nearly isotropic multiplanar reconstruction (MPR) examination in only one plane is necessary, saving both time and radiation exposure. The shorter examination requires the use of higher concentrated contrast medium (400 mg of iodine/ml). The use of such a contrast medium produces a higher degree of contrast enhancement and provides a 5-10% higher contrast between the surrounding normal and pathological tissue, but is more time critical. MPRs are easily done in any plane within seconds and enables also three-dimensional visualization, what helps in the use of minimal invasive therapy, training and teaching and provides a way of handling the hundreds of images acquired during scanning

Contrast-enhanced fat- suppression MR imaging of avascular necrosis of femoral head

Energy Technology Data Exchange (ETDEWEB)

Oh, Tae Kyoung; Shim, Jae Chan; Lee, Ghi Jai; Jeon, Jeong Dong; Bang, Sun Woo; Kim, Ho Kyun [College of Medicine, Inje University, Seoul (Korea, Republic of)

2000-02-01

To evaluate the findings and role of contrast-enhanced fat suppression MR imaging in avascular necrosis (AVN) of the femoral head. In 15 patients with AVN of the femoral head, MR T1-weighted and T2-weighted images and contrast-enhanced fat-suppression T1-weighted images were obtained, and the findings were reviewed. Early and advanced groups were classified on the basis of clinical findings and imaging, and the enhancement pattern was classified as either type I, rim enhancement; type II, surrounding diffuse enhancement; type III, intralesional enhancement; or type IV, II + III. Twenty-four cases of AVN of the femoral head were detected; in nine patients, lesions were bilateral. Eight cases occurred in the early group and 16 in the advanced. All eight in the early group showed the 'double line sign' on T2-weighted images, with a type-I enhancement pattern. In the advanced group, type II (8/16) and type IV (8/16) enhancement patterns were seen. Among the cases showing the type-IV pattern, the intralesional enhancing area showed low signal intensity on T1-weighted images and isosignal intensity on T2-weighted in one case, and low signal intensity on T2-weighted in one case, and low signal intensity on T1-weighted images and high signal intensity on T2-weighted in the other cases. There was no difference in the extent of the disease before and after enhancement. Contrast-enhanced fat-suppression MR images may be helpful in evaluating the extent of AVN of the femoral head and predicting the histopathologic findings of the disease. (author)

Contrast-enhanced fat- suppression MR imaging of avascular necrosis of femoral head

International Nuclear Information System (INIS)

Oh, Tae Kyoung; Shim, Jae Chan; Lee, Ghi Jai; Jeon, Jeong Dong; Bang, Sun Woo; Kim, Ho Kyun

2000-01-01

To evaluate the findings and role of contrast-enhanced fat suppression MR imaging in avascular necrosis (AVN) of the femoral head. In 15 patients with AVN of the femoral head, MR T1-weighted and T2-weighted images and contrast-enhanced fat-suppression T1-weighted images were obtained, and the findings were reviewed. Early and advanced groups were classified on the basis of clinical findings and imaging, and the enhancement pattern was classified as either type I, rim enhancement; type II, surrounding diffuse enhancement; type III, intralesional enhancement; or type IV, II + III. Twenty-four cases of AVN of the femoral head were detected; in nine patients, lesions were bilateral. Eight cases occurred in the early group and 16 in the advanced. All eight in the early group showed the 'double line sign' on T2-weighted images, with a type-I enhancement pattern. In the advanced group, type II (8/16) and type IV (8/16) enhancement patterns were seen. Among the cases showing the type-IV pattern, the intralesional enhancing area showed low signal intensity on T1-weighted images and isosignal intensity on T2-weighted in one case, and low signal intensity on T2-weighted in one case, and low signal intensity on T1-weighted images and high signal intensity on T2-weighted in the other cases. There was no difference in the extent of the disease before and after enhancement. Contrast-enhanced fat-suppression MR images may be helpful in evaluating the extent of AVN of the femoral head and predicting the histopathologic findings of the disease. (author)

Three-dimensional magnetic resonance imaging analysis of hip morphology in the assessment of femoral acetabular impingement

International Nuclear Information System (INIS)

Kavanagh, E.C.; Read, P.; Carty, F.; Zoga, A.C.; Parvizi, J.; Morrison, W.B.

2011-01-01

Aim: To determine a possible association between femoral-acetabular impingement (FAI) volume and the development of labral tear using a three-dimensional (3D) model reconstruction of the acetabulum and the femoral head. Materials and methods: Magnetic resonance arthrography images of the hip in 42 patients with pain and suspected labral tear were acquired using a 1.5 T MRI machine. Using 3D analysis software, outlines of the acetabular cup and femoral head were drawn and 3D reconstruction obtained. To control for differences in patient size, ratios of acetabulum : femoral head volume (AFV) and acetabulum : femoral head surface area (AFA) were used for analysis. The association between volume of acetabulum : femoral head and FAI was investigated using ANOVA analysis. Results: There were 19 men and 23 women with a mean age of 39 years (range 18-78 years). The average AFV was 0.64 (range 0.37-1.05, SD 0.16) and AFA was 0.73 (range 0.36-1.26, SD 0.23). Herniation pit was significantly associated with a small AFV. Conclusion: Femoral neck herniation pits are associated with a low AFV. Gross volume and surface area ratios do not appear to correlate with labral tears or cartilage loss. This technique will enable more advanced analysis of morphological variations associated with FAI.

Prebiopsy magnetic resonance spectroscopy and imaging in the diagnosis of prostate cancer

International Nuclear Information System (INIS)

Kumar, V.; Jagannathan, N.R.; Thulkar, S.; Kumar, R.

2012-01-01

Existing screening investigations for the diagnosis of early prostate cancer lack specificity, resulting in a high negative biopsy rate. There is increasing interest in the use of various magnetic resonance methods for improving the yield of transrectal ultrasound-guided biopsies of the prostate in men suspected to have prostate cancer. We review the existing status of such investigations. A literature search was carried out using the Pubmed database to identify articles related to magnetic resonance methods for diagnosing prostate cancer. References from these articles were also extracted and reviewed. Recent studies have focused on prebiopsy magnetic resonance investigations using conventional magnetic resonance imaging, dynamic contrast enhanced magnetic resonance imaging, diffusion weighted magnetic resonance imaging, magnetization transfer imaging and magnetic resonance spectroscopy of the prostate. This marks a shift from the earlier strategy of carrying out postbiopsy magnetic resonance investigations. Prebiopsy magnetic resonance investigations has been useful in identifying patients who are more likely to have a biopsy positive for malignancy. Prebiopsy magnetic resonance investigations has a potential role in increasing specificity of screening for early prostate cancer. It has a role in the targeting of biopsy sites, avoiding unnecessary biopsies and predicting the outcome of biopsies. (author)

MR-eyetracker: a new method for eye movement recording in functional magnetic resonance imaging.

Science.gov (United States)

Kimmig, H; Greenlee, M W; Huethe, F; Mergner, T

1999-06-01

We present a method for recording saccadic and pursuit eye movements in the magnetic resonance tomograph designed for visual functional magnetic resonance imaging (fMRI) experiments. To reliably classify brain areas as pursuit or saccade related it is important to carefully measure the actual eye movements. For this purpose, infrared light, created outside the scanner by light-emitting diodes (LEDs), is guided via optic fibers into the head coil and onto the eye of the subject. Two additional fiber optical cables pick up the light reflected by the iris. The illuminating and detecting cables are mounted in a plastic eyepiece that is manually lowered to the level of the eye. By means of differential amplification, we obtain a signal that covaries with the horizontal position of the eye. Calibration of eye position within the scanner yields an estimate of eye position with a resolution of 0.2 degrees at a sampling rate of 1000 Hz. Experiments are presented that employ echoplanar imaging with 12 image planes through visual, parietal and frontal cortex while subjects performed saccadic and pursuit eye movements. The distribution of BOLD (blood oxygen level dependent) responses is shown to depend on the type of eye movement performed. Our method yields high temporal and spatial resolution of the horizontal component of eye movements during fMRI scanning. Since the signal is purely optical, there is no interaction between the eye movement signals and the echoplanar images. This reasonably priced eye tracker can be used to control eye position and monitor eye movements during fMRI.

Magnetic resonance imaging in obstetric diagnosis.

Science.gov (United States)

Weinreb, J C; Lowe, T W; Santos-Ramos, R; Cunningham, F G; Parkey, R

1985-01-01

Five patients with abnormal pregnancies were examined with ultrasound (US) and magnetic resonance imaging (MR). Three had a malformed fetus, 1 had a molar pregnancy, and 1 had an ovarian mass. Both maternal and fetal structures were clearly shown, although fetal motion may have resulted in image degradation in some cases. The authors suggest that MR may be useful in obstetric diagnosis.

Magnetic resonance imaging of semicircular canals.

Science.gov (United States)

Sbarbati, A; Leclercq, F; Zancanaro, C; Antonakis, K

1992-01-01

The present paper reports the results of the first investigation of the semicircular canals in a living, small animal by means of high spatial resolution magnetic resonance imaging. This procedure is noninvasive and allows identification of the endolymphatic and perilymphatic spaces yielding a morphology quite consistent with direct anatomical examination. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:1506290

The introduction of clinical magnetic resonance imaging in Australia

International Nuclear Information System (INIS)

Sorby, W.; Baddeley, H.

1986-01-01

Magnetic resonance imaging is a new, but expensive, modality that is being introduced into clinical use in Australia. While it promises increased safety and accuracy in many situations, its precise role when compared with computed tomography and other modalities is not fully established. Therefore, a Government financed evaluation of costs and efficacy of magnetic resonance imaging units in five teaching hospitals is to be conducted over two years (1986-1988). Experience with the introduction of computed tomography to Australia and other nations has revealed difficulties in the evaluation by conventional methods of a diagnostic technology that is improving rapidly; it is to be hoped that a systematic evaluation of the clinical applications of magnetic resonance imaging will be more achievable and useful

Marrow pattern in the proximal femoral metaphysis of patients with osteonecrosis of femoral head and normal subjects: comparison on MR images

International Nuclear Information System (INIS)

Chun, Ho Jong; Park, Jeong Mi; Kim, Jee Young; Lim, Gye Yeon; Yang, Po Song; Kim, Euy Neyong; Kim, Choon Yul; Shinn, Kyung Sub

1996-01-01

To predict early risk of osteonecrosis of the femoral head by comparison of the bone marrow pattern of the proximal femoral metaphysis(PFM) in normal subjects and patients with osteonecrosis of the femoral head on T1-weighted magnetic resonance(MR) images. The authors retrospectively reviewed T1(TR 525/TE 25 msec) weighted coronal MR images of 67 hips with osteonecrosis and 65 normal hips in 39 patients with osteonecrosis of the femoral head and in 27 normal subjects. On the basis of bright signal intensity of fat, the proportion of remaining hematopoietic marrow in PFM was subdivided into 4 grades (0 to 3) by two radiologists. No evidence of remaining hematopoietic marrow was assigned grade 0, and grades 1, 2 and 3 represented scanty, moderate, and prominent hematopoietic marrow, respectively. Grades 0 and 1 were collectively defined as 'predominantly fatty', grades 2 and 3 as 'predominantly hematopoietic'. The frequency of the predominantly fatty marrow in PFM was analyzed in relation to three age groups (<25, 25-50, 50<) and both sexes. The overall frequency of predominantly fatty marrow in PFM was higher in hips with osteonecrosis than in normal hips (p<0.001). Especially in the male population under the age of 50, the frequency was apparently higher in hips with osteonecrosis, compared with normal hips (p<0.0001). However, the male population aged over 50 or female population showed no statistically significant difference in our series. In proximal femoral metaphysis with osteonecrosis of the femoral head, fatty marrow conversion occurs apparently earlier than in normal subject. T1-weighted MR imaging could therefore be useful in predicting early risk of osteonecrosis of the femoral head because of early fatty marrow conversion of the proximal femoral metaphysis

Brain Imaging Using Hyperpolarized 129Xe Magnetic Resonance Imaging.

Science.gov (United States)

Chahal, Simrun; Prete, Braedan R J; Wade, Alanna; Hane, Francis T; Albert, Mitchell S

2018-01-01

Hyperpolarized (HP) 129 Xe magnetic resonance imaging (MRI) is a novel iteration of traditional MRI that relies on detecting the spins of 1 H. Since 129 Xe is a gaseous signal source, it can be used for lung imaging. Additionally, 129 Xe dissolves in the blood stream and can therefore be detectable in the brain parenchyma and vasculature. In this work, we provide detailed information on the protocols that we have developed to image 129 Xe within the brains of both rodents and human subjects. © 2018 Elsevier Inc. All rights reserved.

Magnetic resonance imaging in neuroradiology

International Nuclear Information System (INIS)

Voigt, K.; Lotx, J.W.

1990-01-01

Magnetic resonance imaging (MRI) is now accepted as an effective method of investigating a wide range of disorders, especially of the brain and spine. A short introduction on image contrast in MRI is given and the advantages and disadvantages for the different diseases of the brain is discussed. Excellent soft-tissue contrast, multiplanar imaging capabilities and lack of ionising radiation are conspicuous advantages, and it is now established as the investigation of choice in a large number of clinical conditions, especially when the central nervous system is involved. However, it remains only one of a series of imaging modalities. A confident provisional clinical diagnosis is essential for establishing an imaging protocol and the intention should always be to reach a definitive diagnosis in the least invasive and most cost-effective way. 7 figs., 19 refs

Magnetic Resonance Imaging of Liver Metastasis.

Science.gov (United States)

Karaosmanoglu, Ali Devrim; Onur, Mehmet Ruhi; Ozmen, Mustafa Nasuh; Akata, Deniz; Karcaaltincaba, Musturay

2016-12-01

Liver magnetic resonance imaging (MRI) is becoming the gold standard in liver metastasis detection and treatment response assessment. The most sensitive magnetic resonance sequences are diffusion-weighted images and hepatobiliary phase images after Gd-EOB-DTPA. Peripheral ring enhancement, diffusion restriction, and hypointensity on hepatobiliary phase images are hallmarks of liver metastases. In patients with normal ultrasonography, computed tomography (CT), and positron emission tomography (PET)-CT findings and high clinical suspicion of metastasis, MRI should be performed for diagnosis of unseen metastasis. In melanoma, colon cancer, and neuroendocrine tumor metastases, MRI allows confident diagnosis of treatment-related changes in liver and enables differential diagnosis from primary liver tumors. Focal nodular hyperplasia-like nodules in patients who received platinum-based chemotherapy, hypersteatosis, and focal fat can mimic metastasis. In cancer patients with fatty liver, MRI should be preferred to CT. Although the first-line imaging for metastases is CT, MRI can be used as a problem-solving method. MRI may be used as the first-line method in patients who would undergo curative surgery or metastatectomy. Current limitation of MRI is low sensitivity for metastasis smaller than 3mm. MRI fingerprinting, glucoCEST MRI, and PET-MRI may allow simpler and more sensitive diagnosis of liver metastasis. Copyright © 2016 Elsevier Inc. All rights reserved.

Role of magnetic resonance imaging in entrapment and compressive neuropathy - what, where, and how to see the peripheral nerves on the musculoskeletal magnetic resonance image: part 1. Overview and lower extremity

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Kim, Sungjun [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea); Hanyang University, Kuri Hospital, Department of Diagnostic Radiology, College of Medicine, Kuri City, Kyunggi-do (Korea); Choi, Jin-Young; Huh, Yong-Min; Song, Ho-Taek; Lee, Sung-Ah [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea); Kim, Seung Min [Yonsei University, Department of Neurology, College of Medicine, Seoul (Korea); Suh, Jin-Suck [Yonsei University, Department of Diagnostic Radiology, College of Medicine, Seoul (Korea); Yonsei University, Research Institute of Radiological Science, College of Medicine, Seoul (Korea)

2007-01-15

The diagnosis of nerve entrapment and compressive neuropathy has been traditionally based on the clinical and electrodiagnostic examinations. As a result of improvements in the magnetic resonance (MR) imaging modality, it plays not only a fundamental role in the detection of space-occupying lesions but also a compensatory role in clinically and electrodiagnostically inconclusive cases. Although ultrasound has undergone further development in the past decades and shows high resolution capabilities, it has inherent limitations due to its operator dependency. We review the general concepts that should be known to evaluate the entrapment and compressive neuropathy in MR imaging. We also review the course of normal peripheral nerves, as well as various clinical demonstrations and pathological features of compressed and entrapped nerves in the lower extremities on MR imaging, according to the nerves involved. The common sites of nerve entrapment of the lower extremity are as follows: sciatic nerve around the piriformis muscle; tibial nerve at the popliteal fossa and tarsal tunnel, common peroneal nerve around the fibular neck, and digital nerve near the metatarsal head. Although MR imaging can depict the peripheral nerves in the extremities effectively, radiologists should be familiar with nerve pathways, common sites of nerve compression, and common space-occupying lesions resulting in nerve compression in MR imaging. (orig.)

Role of magnetic resonance imaging in entrapment and compressive neuropathy - what, where, and how to see the peripheral nerves on the musculoskeletal magnetic resonance image: part 1. Overview and lower extremity

International Nuclear Information System (INIS)

Kim, Sungjun; Choi, Jin-Young; Huh, Yong-Min; Song, Ho-Taek; Lee, Sung-Ah; Kim, Seung Min; Suh, Jin-Suck

2007-01-01

The diagnosis of nerve entrapment and compressive neuropathy has been traditionally based on the clinical and electrodiagnostic examinations. As a result of improvements in the magnetic resonance (MR) imaging modality, it plays not only a fundamental role in the detection of space-occupying lesions but also a compensatory role in clinically and electrodiagnostically inconclusive cases. Although ultrasound has undergone further development in the past decades and shows high resolution capabilities, it has inherent limitations due to its operator dependency. We review the general concepts that should be known to evaluate the entrapment and compressive neuropathy in MR imaging. We also review the course of normal peripheral nerves, as well as various clinical demonstrations and pathological features of compressed and entrapped nerves in the lower extremities on MR imaging, according to the nerves involved. The common sites of nerve entrapment of the lower extremity are as follows: sciatic nerve around the piriformis muscle; tibial nerve at the popliteal fossa and tarsal tunnel, common peroneal nerve around the fibular neck, and digital nerve near the metatarsal head. Although MR imaging can depict the peripheral nerves in the extremities effectively, radiologists should be familiar with nerve pathways, common sites of nerve compression, and common space-occupying lesions resulting in nerve compression in MR imaging. (orig.)

Assessment of coronary artery disease with nicorandil stress magnetic resonance imaging

International Nuclear Information System (INIS)

Kawase, Yoshio; Nichimoto, Masaki; Hato, Katsunori; Okajima, Kazue; Yoshikawa, Junichi

2004-01-01

Although dipyridamole and adenosine have been used as vasodilator agents, we believe they are inadequate for vasodilator perfusion magnetic resonance imaging, due to adverse effects (flushing, warmth, headaches, and arrhythmia). Nicorandil, a potassium channel opener, has been reported to increase coronary blood flow and it was associated with fewer adverse effects than adenosine or dipiridamole. We set out to investigate whether the coronary artery stenosis could be assessed by nicorandil stress perfusion magnetic resonance imaging. First-pass contrast-enhanced magnetic resonance images of the left ventricle acquired from 50 patients at rest and during intravenous administration of nicorandil using multi-slice turbo field echo with multi shot echo-planar-imaging. Coronary angiography was performed within 1 week. There was no adverse effects during nicorandil stress in any patients. The overall sensitivity and specificity of magnetic resonance imaging in identifying patients with significant stenosis of at least one coronary artery were 93.9% (31 of 33 patients) and 94.1% (16 of 17 patients), respectively. The sensitivity of magnetic resonance imaging for detecting significant stenosis in the left anterior descending artery was 87.5%; the sensitivity in the left circumflex artery was 80%; the sensitivity in the right coronary artery was 92.3%. Similar sensitivities were observed for all 3 vascular regions, indicating that all myocardial segments were visualized with similar image quality. The present study shows that nicorandil stress perfusion magnetic resonance imaging is a safe, feasible technique for assessing coronary artery stenosis severity in a totally-noninvasive manner. (authors)

Adjunctive role of preoperative liver magnetic resonance imaging for potentially resectable pancreatic cancer.

Science.gov (United States)

Kim, Hyoung Woo; Lee, Jong-Chan; Paik, Kyu-Hyun; Kang, Jingu; Kim, Young Hoon; Yoon, Yoo-Seok; Han, Ho-Seong; Kim, Jaihwan; Hwang, Jin-Hyeok

2017-06-01

The adjunctive role of magnetic resonance imaging of the liver before pancreatic ductal adenocarcinoma has been unclear. We evaluated whether the combination of hepatic magnetic resonance imaging with multidetector computed tomography using a pancreatic protocol (pCT) could help surgeons select appropriate candidates and decrease the risk of early recurrence. We retrospectively enrolled 167 patients in whom complete resection was achieved without grossly visible residual tumor; 102 patients underwent pCT alone (CT group) and 65 underwent both hepatic magnetic resonance imaging and pCT (magnetic resonance imaging group). By adding hepatic magnetic resonance imaging during preoperative evaluation, hepatic metastases were newly discovered in 3 of 58 patients (5%) without hepatic lesions on pCT and 17 of 53 patients (32%) with indeterminate hepatic lesions on pCT. Patients with borderline resectability, a tumor size >3 cm, or preoperative carbohydrate antigen 19-9 level >1,000 U/mL had a greater rate of hepatic metastasis on subsequent hepatic magnetic resonance imaging. Among 167 patients in whom R0/R1 resection was achieved, the median overall survival was 18.2 vs 24.7 months (P = .020) and the disease-free survival was 8.5 vs 10.0 months (P = .016) in the CT and magnetic resonance imaging groups, respectively (median follow-up, 18.3 months). Recurrence developed in 82 (80%) and 43 (66%) patients in the CT and magnetic resonance imaging groups, respectively. The cumulative hepatic recurrence rate was greater in the CT group than in the magnetic resonance imaging group (P magnetic resonance imaging should be considered in patients with potentially resectable pancreatic ductal adenocarcinoma, especially those with high tumor burden. Copyright © 2017 Elsevier Inc. All rights reserved.

Brain-heart interactions: challenges and opportunities with functional magnetic resonance imaging at ultra-high field.

Science.gov (United States)

Chang, Catie; Raven, Erika P; Duyn, Jeff H

2016-05-13

Magnetic resonance imaging (MRI) at ultra-high field (UHF) strengths (7 T and above) offers unique opportunities for studying the human brain with increased spatial resolution, contrast and sensitivity. However, its reliability can be compromised by factors such as head motion, image distortion and non-neural fluctuations of the functional MRI signal. The objective of this review is to provide a critical discussion of the advantages and trade-offs associated with UHF imaging, focusing on the application to studying brain-heart interactions. We describe how UHF MRI may provide contrast and resolution benefits for measuring neural activity of regions involved in the control and mediation of autonomic processes, and in delineating such regions based on anatomical MRI contrast. Limitations arising from confounding signals are discussed, including challenges with distinguishing non-neural physiological effects from the neural signals of interest that reflect cardiorespiratory function. We also consider how recently developed data analysis techniques may be applied to high-field imaging data to uncover novel information about brain-heart interactions. © 2016 The Author(s).

Correlation between baseline femoral neck marrow status and the development of femoral head osteonecrosis in corticosteroid-treated patients: A longitudinal study by MR imaging

International Nuclear Information System (INIS)

Vande Berg, Bruno C.; Gilon, Raphael; Malghem, Jacques; Lecouvet, Frederic; Depresseux, Genevieve; Houssiau, Frederic A.

2006-01-01

Objective: To test the hypothesis that the development of corticosteroid (CS)-associated femoral head osteonecrosis (ON) is influenced by baseline femoral neck marrow status. Patients and methods: The population consisted of 20 untreated patients with a newly diagnosed rheumatic disease in whom a standardized CS regimen was planned. Before CS treatment, baseline femoral neck marrow status was determined by magnetic resonance (MR) imaging on T1-weighted images (proportion of surface area of femoral neck and intertrochanteric area occupied by fatty marrow; index of marrow conversion [IMC]) and on a quantitative MR sequence (bulk T1 values of femoral head and neck). The presence of ON was assessed by coronal T1-weighted MR images of the hips at 6 and 12 months. Results: None of the patients suffered from ON at baseline. Four patients (20%) developed bilateral femoral head ON at 6 months. The mean percentage of fat marrow in the femoral neck before treatment was significantly higher in ON-positive than in ON-negative patients (p = 0.0025). The mean baseline femoral neck IMC value, which parallels the degree of red to yellow marrow conversion, was higher in ON-positive than in ON-negative patients (p = 0.089). The mean baseline bulk T1 value of the femoral neck (but not of the femoral head), which inversely correlates with the amount of fat marrow, was significantly shorter in ON-positive than in ON-negative patients (p = 0.0298). Conclusion: The development of CS-associated femoral head ON is correlated with a high fat content in the proximal femur before CS therapy