Acute spontaneous spinal epidural hematomas.

BACKGROUND AND PURPOSE: Although previous reports have characterized MR imaging features of spinal epidural hematomas (EDH), few cases have been reported during the acute or hyperacute phase within the first 48 hours. Our goal in this investigation was to correlate the MR imaging features of acute (< or =48 hours) spontaneous EDH with clinical management and outcome. METHODS: Eight patients with acute spontaneous EDH (five men and three women; age range, 31-81 years) underwent MR imaging at 1.5 T (T1-weighted, n = 8; T1-weighted after the administration of 0.1 mmol/kg contrast material, n = 6; T2-weighted, n = 8; and T2-weighted, n = 4). The interval from symptom onset to hospital admission ranged from immediate to 5 days. Two neuroradiologists reviewed the MR images for signal characteristics, contrast enhancement, and cord compression. Treatment and clinical outcome were correlated with the imaging findings. RESULTS: The EDH were located in the cervical (n = 3), cervicothoracic (n = 2), thoracolumbar (n = 2), and lumbar (n = 1) regions. On T1-weighted images, the signal intensity of the EDH was isointense to spinal cord in five cases, hyperintense in two cases, and hypointense in one case and did not correlate with time to imaging. Isointensity on T1-weighted images persisted for 5 days in one case. On T2-weighted images, all EDHs were hyperintense with focal, heterogeneous hypointensity. Cord compression was severe in six patients, moderate in one patient, and minimal in one patient. Four cases were treated conservatively with complete resolution or improvement of symptoms within 1 to 3 weeks. CONCLUSION: MR imaging findings were useful in establishing the diagnosis of EDH but did not influence management or predict outcome in this series. Heterogeneous hyperintensity to cord with focal hypointensity on T2-weighted images should suggest the diagnosis of acute spinal EDH. Severity of neurologic impairment had the greatest impact on management and outcome. Nonoperative treatment may be successful in cases with minimal neurologic deficits, despite cord compression revealed by MR imaging.     

Chronic injuries of the spinal cord: assessment with MR imaging

Seventy-six patients with persistent myelopathy secondary to chronic spinal cord injuries underwent examination with magnetic resonance (MR) imaging, the results of which were correlated with neurologic findings. Twenty-one patients received follow-up study during and after the acute stage; 55 patients were examined only at a chronic stage. Spinal cord abnormalities were seen in 48 patients according to five patterns: (a) normal signal intensity on T1- and T2-weighted images (pattern N/N, n = 28), (b) normal signal intensity on T1-weighted and hyperintensity on T2-weighted images (pattern N/Hi, n = 18), (c) hypointensity on T1-weighted and hyperintensity on T2-weighted images (pattern Lo/Hi, n = 17), (d) cord atrophy (n = 5), and (e) longitudinal syrinx formation with hypointensity on T1- and hyperintensity or isointensity on T2-weighted images (n = 8). Patients with pattern N/N had only slight neurologic damage and an excellent prognosis. Patients with pattern N/Hi had mild neurologic impairment, frequently associated with cord compression. Patients with pattern Lo/Hi had the worst prognosis. Atrophy was observed in patients with a long history of myelopathy.     

MRI of musculoskeletal extraspinal tuberculosis

PURPOSE: The aim of this study was to describe the MR findings in extraspinal musculoskeletal tuberculosis (EMT). METHOD: A retrospective review was conducted of the MR findings of 18 patients with microbiologically and/or pathologically proven EMT. All MR studies were performed using T1-and T2-weighted spin echo sequences. T1-weighted spin echo sequences after Gd-DTPA injection were obtained for 12 patients. The MR images were evaluated for abnormalities in joints, bones, and soft tissues, and the results were grouped by anatomic localization, frequency distribution of structures affected, and morphologic patterns of involvement. RESULTS: Isolated soft tissue tuberculosis was found in 10 (55.5%) patients and involvement of more than one structure in 8 (44.4%). Pyomyositis (n = 6) and arthritis with involvement of adjacent soft tissues (n = 7) were the most common forms of presentation. One patient presented with isolated fascial superficial tissue involvement in one leg. Isolated pyomyositis involving one (n = 3) or two (n = 3) muscles was homogeneous in six cases and showed intermediate (n = 6), low (n = 2), or high (n = 1) signal intensity on T1-weighted images and a high and very hyperintense signal on T2-weighted images. The tenosynovitis synovial fluid was homogeneous (n = 1) or heterogeneous with multiple tiny hypointense nodules (n = 1) on T2-weighted images. The subdeltoid bursitis fluid was characterized by homogeneous low signal intensity with a hyperintense rim (n = 2) on T1-weighted images and homogeneous (n = 1) or heterogeneous hyperintense signals with areas of low signal intensity (n = 1) on T2-weighted images. In tuberculous arthritis, the synovial joint fluid (n = 7) showed heterogeneous (n = 4) or homogeneous (n = 3) low signal intensity on T1-weighted images and high or very high signal intensity on T2-weighted images. Where involved, the adjacent muscle(s) (n = 8) were usually hypointense on T1-weighted images and very hyperintense on T2-weighted images. Associated cellulitis was found in arthritis with involvement of neighboring soft tissues (n = 5), pyomyositis (n = 2), and tenosynovitis (n = 1). The images obtained after Gd-DTPA showed peripheral (n = 10) or heterogeneous (n = 1) enhancement or no enhancement (n = 1). CONCLUSION: The MR findings for EMT are variable. Although diagnosis is dependent largely on prior presumption and clinical context, MRI provides valuable guidelines in defining the extent of the lesions to select the appropriate treatment and for follow-up of abnormalities.     

Solitary fibrous tumor of the pleura: MR appearance and enhancement pattern

PURPOSE: The aim of the current study was to characterize the MR appearance of solitary fibrous tumor of the pleura (SFTP). METHOD: Twenty-two consecutive patients with histologically confirmed SFTP were retrospectively evaluated with MRI. RESULTS: Tumors demonstrated low signal intensity (n = 18, 82%), iso signal intensity (n = 2, 9%), and high signal intensity (n = 2, 9%) on T1-weighted images. On T2-weighted images, tumors were observed as low signal intensity (n = 10, 45%), high signal intensity (n = 2, 9%), and mixed signal intensity (n = 10, 45%). Solid component in the proliferation of tumor cells corresponded to low signal intensity in 12 tumors (55%) on T2-weighted images. On gadolinium-enhanced T1-weighted images, inhomogeneous enhancement (n = 18, 82%), nodular enhancement (n = 6, 27%), and homogeneous enhancement (n = 4, 18%) were observed. The enhanced lesion within the tumors had dense tumor tissue and dilated microvessels in the pathologic specimen. CONCLUSION: SFTP shows variable appearance and enhancement pattern on MRI according to morphologic tumor heterogeneity.     

Colorectal mucinous carcinoma: findings on MRI

PURPOSE: The purpose of this work was to define the characteristic MR features of colorectal mucinous carcinomas and to correlate the mucin pool with the signal intensity of this tumor. METHOD: MRI of 12 cases of pathologically proven colorectal carcinoma containing mucin was evaluated. We analyzed the signal intensity of tumor on T1- and T2-weighted MR images and correlated the area of intratumoral high signal intensity on T2-weighted images with the mucinous pool on the pathologic specimens. Two radiologists independently estimated the area of high signal intensity in the tumor on T2-weighted images and one pathologist estimated the amount of mucinous pool in the pathologic specimen. RESULTS: In 9 (75%) of 12 cases, focal or diffuse high signal intensity areas were detected on T2-weighted fast spin echo images. In seven cases in which mucin pools were seen macroscopically, partial (n = 3) or diffuse high signal intensity areas were noted on the T2-weighted images. Among the five cases in which microscopic mucinous pools were detected on the pathologic slides, three cases showed no high signal foci on MR images, and in the remaining two cases, high signal intensity areas were noted as small foci. CONCLUSION: Intratumoral high signal intensity on T2-weighted fast spin echo MR images occurs in mucinous carcinomas and correlates with the mucin pools on pathologic specimens.     

MR appearance of rhinoscleroma.

BACKGROUND AND PURPOSE: We describe the MR imaging appearance of rhinoscleroma, an endemic, chronic, granulomatous disease whose causative agent is Klebsiella rhinoscleromatis. METHODS: The study included 15 patients (nine males and six females; mean age, 25 years; range, 13-36 years) with rhinoscleroma. MR imaging was performed in all patients. The signal intensity of the nasal masses was compared with that of fat, muscle, and CSF on both T1- and T2-weighted images. All cases were proved by histopathologic examination. RESULTS: The nasal masses were bilateral and symmetrical (n = 6), asymmetrical (n = 4), or unilateral (n = 5). They extended through the anterior nares (n = 9) or posterior choana into the nasopharynx (n = 3). They obstructed the ostiomeatal units with retained secretions in the related sinuses (n = 10). On T1-weighted images, rhinoscleroma showed striking (n = 9) or mild (n = 6) high signal intensity relative to muscle and CSF, but less hyperintensity than fat. On T2-weighted images, the nasal masses showed homogeneous high signal intensity (n = 10) or heterogeneous high signal intensity associated with hypointense foci (n = 5). They were hyperintense relative to fat and muscle, but less hyperintense than CSF. CONCLUSION: The hypertrophic stage of rhinoscleroma has characteristic mild to marked high signal intensity on both T1- and T2-weighted MR images.     

MR of the submandibular gland: normal and pathologic states.

PURPOSETo evaluate the MR appearance of normal and pathologic states of the submandibular gland.METHODSMR images of 22 healthy subjects and 21 patients with histopathologically confirmed disorders of the submandibular gland (five pleomorphic adenomas, two hemangiomas, two malignant lymphomas, one adenoid cystic carcinoma, one squamous cell carcinoma, and 10 cases of sialadenitis) were reviewed.RESULTSAll normal submandibular glands showed higher signal intensity than surrounding muscle but lower intensity than fat on T1-weighted and T2-weighted images. Postcontrast images showed moderate enhancement of the gland. All the tumors had lower signal intensity than the normal submandibular gland on T1-weighted images and had intermediate to high (n = 8) or high (n = 3) signal intensity relative to the normal submandibular gland on T2-weighted images. Six of seven benign tumors were well defined, and three of four malignant tumors were poorly defined. In all cases of sialadenitis, the submandibular gland showed diffusely different signal intensities from the normal gland on both T1-weighted and T2-weighted images. Eight cases of chronic sialadenitis showed lower T2-weighted signal intensities than the normal gland, and this can be explained histopathologically by marked fibrosis and cellular infiltration.CONCLUSIONSMR imaging can show the presence, extent, margins, and signal intensity changes of pathologic conditions of the submandibular gland.     

Neuroendocrine tumors of the pancreas: spectrum of appearances on MRI

We reviewed our 8.5 year experience with magnetic resonance imaging (MRI) in the demonstration of neuroendocrine tumors of the pancreas using precontrast fat-suppressed T1-weighted, fat-suppressed T2-weighted, and serial post-gadolinium T1-weighted images, to describe the spectrum of appearances of these tumors. All MR examinations of patients with histologically proven neuroendocrine tumors were retrospectively reviewed. Histological type, tumor location, tumor diameter, signal intensity on precontrast images, enhancement patterns, and presence and appearance of metastases were determined. Twenty-two patients had histologically proved neuroendocrine tumors detected by MRI over the 8.5 year period. Histological types were gastrinoma (n = 8), insulinoma (n = 3), glucagonoma (n = 2), somatostatinoma (n = 1), VIPoma (n = 1), ACTHoma (n = 1), carcinoid (n = 1), and five untyped tumors. Primary tumors ranged in diameter from 1 to 6.2 cm. There was one histopathology-proven false-positive neuroendocrine tumor. The positive predictive value for MRI in the detection of these tumors was 96%. The most common appearance on precontrast images was low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, which was observed in tumors in 18 of 22 patients. Moderate or intense early enhancement of all or portions of the primary tumors was observed in tumors in 19 of 22 patients either as uniform homogeneous, ring, or diffuse heterogeneous enhancement. Enhancement was minimal on these images in the other three patients. Gastrinomas enhanced in a ring pattern in 7 of 8 patients whereas the majority (9 of 11 patients) of noninsulinoma-nongastrinoma and untyped tumors enhanced in a diffuse heterogeneous fashion. Liver metastases were present in 13/22 patients including 3/8 with gastrinoma and 9/11 with noninsulinoma-nongastrinoma tumors. Most neuroendocrine tumors of the pancreas are low signal intensity on fat-suppressed T1-weighted images and moderately high in signal intensity on fat-suppressed T2-weighted images, although variations do exist. Tumors most often enhance in an early moderately intense fashion. Gastrinomas are often different in appearance than other neuroendocrine tumors in that they usually enhance in a ring fashion whereas nongastrinoma-noninsulinoma tumors usually enhance in a heterogeneous fashion.     

High signal intensity lesions of the chest in MR imaging

The majority of pathologic lesions in the lung and mediastinum have relatively long T1 and T2 relaxation times and consequently yield medium to low signal intensity on T1-weighted images. Pulmonary lesions with high signal intensity on T1-weighted images are unusual and raise a special group of diagnostic considerations. In the current study, a mass with a lesion/fat signal intensity ratio of greater than 0.7 on a T1-weighted sequence was considered high signal intensity. The nature of these masses was ganglioneuroma or ganglioneuroblastoma (n = 3), atrial lipoma (lipomatous atrophy of the interatrial septum) (n = 3), pheochromocytoma (n = 2), bronchogenic cyst (n = 2), lymphangioma (n = 1), teratoma (n = 1), and a variety of primary and metastatic tumors of the mediastinum and lung. A single pathologic structure of these lesions was not present, but rather several underlying tissue compositions were noted, including fat, subacute hemorrhage, myxoid material, and cellular composition with high cytoplasmic/nuclear ratio. Thus, high signal intensity lesions of the thorax on T1-weighted images should suggest a number of differential diagnoses.     

Spinal epidural cavernous hemangioma: MR findings

PURPOSE: Cavernous hemangiomas with a spinal epidural location are very uncommon vascular tumors in contrast to those in the vertebral body. The purpose of this study was to describe the radiologic findings, focusing on the MR studies, of spinal epidural cavernous hemangiomas. METHOD: Five pathologically proven cases of spinal epidural cavernous hemangioma were retrospectively reviewed. MR (n = 5) and CT (n = 1) were evaluated. RESULTS: The level was thoracic (n = 4) or lumbosacral (n = 1). The mass was located in the epidural space and showed paravertebral extension in all cases. It showed a lobulated contour in all cases and encircled the spinal cord partially with a larger posterior (n = 3) or anterior (n = 1) component in four cases. In all cases, the mass showed high signal intensity on T2-weighted images and homogeneous, strong enhancement. Adjacent bony erosion (n = 5) and intervertebral neural foraminal widening (n = 4) were common. CONCLUSION: Spinal epidural cavernous hemangioma shows characteristic MR findings of a lobulated contoured epidural mass partially encircling the spinal cord with a larger posterior component in the spinal canal, high signal intensity on T2-weighted images, and homogeneous, strong enhancement.     

阔韧带平滑肌瘤的MR诊断

目的:探讨阔韧带平滑肌瘤的MR表现及诊断价值.方法:回顾性分析13例经手术和病理证实为阔韧带平滑肌瘤的MR表现.结果:13例中肿块位于子宫右侧4例,左侧8例,两侧1例.肿块呈圆形、类圆形10例,不规则形或分叶状3例.肿块大于5 cm占84.6%(11/13).T1WI肿块均呈等或略低信号;T2WI为中等信号,其中11例肿块中见不均匀斑点状、梭条状高信号影,2例见大片状液化坏死灶.注射钆喷替酸葡甲胺(Gd-DTPA)后扫描肿块实质部分明显强化,显示包膜完整,与子宫等周围脏器分界清晰10例,包膜不清,与子宫有粘连且分界不清3例;包膜不强化且显示更清晰.结论:阔韧带平滑肌瘤的MR表现具有一定的特征性:盆腔内、子宫外大而有完整包膜的实性或实性为主的肿块,T1WI呈等或略低信号,T2WI呈中等信号,其内常可见不均匀斑点状、梭条状高信号影,增强扫描肿瘤强化明显.MR具有良好的软组织分辨率、多方位成像的特点,有利于肿瘤结构、成份与包膜显示,对明确诊断有肯定的价值.     

Magnetic resonance imaging of pyomyositis in 43 cases

PURPOSE: To describe the magnetic resonance imaging (MRI) findings in pyomyositis. METHODS AND MATERIALS: Forty-three patients with proven muscle infection (30 males, 13 females) ranging in age from 14 to 86 years (mean 42 years) were studied with MRI. The initial clinical diagnose were soft tissue infection (n=27), neoplasm (n=12), thrombophlebitis (n=3), and lymphedema (n=1). Spin-echo T1- and T2-weighted images were obtained in all cases and STIR sequence in 6. Spin-echo T1-weighted images after Gd-DTPA injection were obtained in 16 cases. The signal intensity findings, the extent of the abnormalities in the soft tissue (muscle, fascial and subcutaneous involvement), the presence of fluid collections, and the involvement of neighbouring bone and joint were reviewed retrospectively. RESULTS: A hyperintense signal on T2-weighted and STIR images were detected in all patients. Fluid collections were seen in 21 cases as localized areas of hypointensity on the T1-weighted images, and highly hyperintense areas on the T2-weighted images. In four patients a rim of high signal intensity was seen around the fluid collection on the T1-weighted images. On contrast-enhanced T1-weighted images there was diffuse enhancement in the patients without fluid collections that was heterogeneous in seven and homogeneous in two. After Gd-DTPA all fluid collections showed a central area without enhancement and a well-defined enhancing peripheral rim. Involvement of adjacent structures included subcutaneous tissue (n=25), bone marrow (n=14), fascial planes (n=15) and joints (n=11). CONCLUSION: MRI is useful in the assessment of pyomyositis and in determining the location and extension. A hyperintense rim on unenhanced T1-weighted images and peripheral enhancement after Gd-DTPA are useful for identifying the number, size, and location of soft-tissue abscesses.     

下肢神经源性肿瘤的MRI表现

目的 评估下肢神经源性肿瘤的MR表现。方法 回顾性分析5例经病理证实的下肢神经源性肿瘤的MR表现，其中4例为神经鞘瘤(3例良性，1例恶性)，1例为恶性神经纤维瘤；肿瘤分别位于小腿(2例)、腘区(1例)、大腿(1例)和股区(1例)。5例均行常规MR扫描，应用T1、T2加权序列作轴面、冠状面和矢状面扫描，2例良性神经鞘瘤应用T1WSE作增强扫描。结果 在T1WI2例良性神经鞘瘤呈等信号强度，1例良性神经鞘瘤、1例恶性神经鞘瘤和1例恶性神经纤维瘤呈不均质的低一中等信号强度。在T2WI5例肿瘤均呈不均质高信号。2例神经鞘瘤可见靶征，表现为瘤体中央为低信号区，其周围为高信号区，于T2WI显示清楚。结论 MRI有利于明确肿瘤的位置和范围，以及外科治疗计划的制定。靶征对周围神经源性肿瘤的诊断是1种有价值的征象。     

滑膜血管瘤的影像学诊断

目的:分析滑膜血管瘤的影像学表现及诊断价值。材料和方法:回顾性分析已确诊12例滑膜血管瘤(男性7例,女性5例),其中膝关节5例、肘关节2例、腕关节2例、髋关节2例、肩关节1例。X线检查8例,CT检查平扫2例,MRI检查5例其中增强4例,血管造影1例。结果:X线平片可以出现静脉石、软组织肿胀、骨质侵蚀、继发骨关节炎表现。CT表现为软组织肿胀及骨质侵蚀,血管造影仅发现膝周少许异常染色血管影。MRI发现局限型(2例)和弥漫型(3例),局限型表现为髌上囊区局限肿块影,T1WI上等低信号影,于T2WI序列表现为高信号;弥漫型2例表现为弥漫性生长可突破关节囊,病灶大部分呈T1WI上等低信号影,T2WI上高信号影,其内含有更低信号细条索影及高信号分隔影。1例含有大量含铁血黄素则T1WI及T2WI上均表现为低信号。结论:X线平片、CT及血管造影对滑膜血管瘤诊断有一定帮助,MRI可明确显示血管瘤特征性脉管及纤维脂肪成分,提高该病术前诊断率。     

Magnetic resonance imaging spectrum of spinal meningioma

PurposeTo evaluate magnetic resonance (MR) imaging findings of spinal meningioma and to determine the radiological subtypes based on the MR imaging findings and their respective clinical features.Material and methodsData for 105 patients with surgically treated and histopathologically diagnosed spinal meningiomas at our hospital between May 1, 2003 and May 1, 2017 were evaluated in this study. Two radiologists reviewed the characteristics of spinal meningiomas on MR images and categorized the spinal meningiomas into subtypes based on MR imaging findings.ResultsMost spinal meningiomas showed higher signal intensity than that of the spinal cord but lower than that of the subcutaneous fat on T2-weighted images (WI). 56 cases (54%) showed adjacent spinal cord signal changes. Meningiomas could be categorized according to MR imaging findings into type A: dural-based tumors with a homogeneous signal intensity and intense contrast enhancement (81 cases, 77%); type B: round or oval-shaped tumors with an internal hypointense portion on T2-weighted images (18 cases, 17%); type C: en plaque tumors (three cases, 3%); and type D: tumors with unusual findings and a heterogeneous appearance (three cases, 3%). All type C patients showed spinal cord signal changes.ConclusionsSpinal meningioma showed slightly high signal intensity rather than high signal intensity on T2-weighted images. Spinal cord signal changes were present in more than half of the cases. Clinical differences were observed among the different MR imaging types.     

MR imaging in radiation myelopathy.

PURPOSE: Using MR imaging, we assessed the signal, size, and enhancing characteristics of the cervical cord in patients in whom radiation myelopathy developed after radiotherapy for nasopharyngeal carcinoma. PATIENTS AND METHODS: Ten patients, 3 men and 7 women, aged from 32 to 77 years, were included. MR imaging was performed 1 to 53 months after clinical manifestations of myelopathy. RESULTS: Two cases showed atrophy of the cervical cord without abnormal signal intensity; in the others, a long segment of the cervical cord demonstrated low signal intensity on T1-weighted images and high signal intensity on T2- or T2*-weighted images. Some of these cases also showed swelling of the cord. Focal enhancement at C1-C2 area after intravenous administration of Gd-DTPA was seen in four cases. CONCLUSIONS: There is a correlation between the time of MR imaging after onset of symptoms and MR findings. When MR scans were obtained more than 3 years after onset of symptoms, atrophy of the cervical cord was noted without abnormal signal intensity. When MR was performed less than 8 months after onset of symptoms, a long segment of the cervical cord demonstrated abnormal signal intensity with or without associated swelling of the cord and focal enhancement.     

胸椎黄韧带骨化性椎管狭窄的MRI和CT对比研究

目的:本文对54例胸椎黄韧带骨化性椎管狭窄患者进行MR和CT对比研究。 材料和方法:男性43例,女性11例,年龄32～78岁。全部患者采用1.0T超导磁共振机,全身CT扫描机,行矢状T_1和T_2W1扫描,T_1W1病变区或/和T_2W1横轴扫描及相似层面的CT横断对照扫描。 结果:54例(108椎间)胸椎黄韧带骨化性椎管狭窄,单椎间发生者14例,多椎间40例(94椎间)。MR主要表现为黄韧带附着区丁T_1W1和T_2W1像增厚的异常低信号影,CT则全部表现为不同程度的骨样密度吸收区。 结论:MR是显示胸椎黄韧带骨化和脊髓受压情况的最佳方法,CT在诊断胸椎黄韧带骨化性椎管狭窄所合并的其他脊柱退行性变方面优于MRI。MRI结合CT平扫为诊断胸椎黄韧带骨化性椎管狭窄的最佳方法。     

MRI and clinical features in amyotrophic lateral sclerosis

MRI of the brain and spinal cord was performed in 21 patients with amyotrophic lateral sclerosis (ALS), 8 normal volunteers and 16 neurological disease controls. High signal was seen in the intracranial corticospinal tract in 16 of the 21 patients on T2-weighted and in 10 on proton density (PD)-weighted images. In one patient, the high signal on T2-weighted images became less marked with progression of the disease. Low signal intensity was seen in the motor cortex in 12 of the 21 patients. High signal in the anterolateral column of the spinal cord on T1 weighted images was seen in 14, and high signal in the lateral corticospinal tract on T2 weighted images was seen in 7 of the 21 patients. The relationship between the abnormal images and upper motor neurone signs remained unclear. High signal intensity was seen in the corticospinal tract in the brain on T2-weighted images in two normal volunteers and four disease controls, and on PD weighted images in three disease controls. Low signal intensity in the motor cortex on T2 weighted images was seen in three normal volunteers and four disease controls. However, high signal intensity was seen in the intracranial corticospinal tract on T1 weighted images in five patients with ALS who showed pronounced upper motor neurone signs including spastic paraparesis, but not in controls. Thus, abnormalities on MRI in the brain and spinal cord should be considered in the diagnosis of ALS, and high signal intensity of the intracranial corticospinal tract on T1-weighted images may reflect the severe pathological changes of the upper motor neurones in ALS. Received: 18 March 1997 Accepted: 2 May 1997     

Relationship between contrast enhancement on fluid-attenuated inversion recovery MR sequences and signal intensity on T2-weighted MR images: visual evaluation of brain tumors

PURPOSE: To investigate the relationship between the degree of contrast enhancement in fluid-attenuated inversion recovery (FLAIR) sequences and tumor signal intensity on T2-weighted images. MATERIALS AND METHODS: A total of 96 patients suspected of having brain tumors were examined by MR imaging, and whenever a brain tumor with an enhancing part larger than the slice thickness was demonstrated on postcontrast T1-weighted images, postcontrast FLAIR images were additionally acquired. The tumor signal intensity on the T2-weighted images was visually classified as follows: equal or lower compared with normal cerebral cortex (group 1), higher than normal cortex (group 2), and as high as cerebrospinal fluid (CSF) (group 3). When a lesion contained several parts with different signal intensities on T2-weighted images, we assessed each part separately. In each group, we visually compared pre- and postcontrast FLAIR images and assessed whether tumor contrast enhancement was present. When contrast enhancement was present on FLAIR sequence, the degree of contrast enhancement in T1-weighted and FLAIR sequences was visually compared. RESULTS: Postcontrast T1-weighted images showed 46 enhancing lesions, including 48 parts, in 31 MR examinations. FLAIR images of the lesion-parts in group 1 (N=18) did not show significant contrast enhancement. In group 2 (N=12), all the parts were enhanced in FLAIR sequences, and three parts were enhanced more clearly in the FLAIR sequences than in the T1-weighted sequences. In group 3 (N=18), all the parts were enhanced equally or more clearly in the FLAIR sequences than in the T1-weighted sequences. CONCLUSION: The signal intensity in FLAIR sequences is largely influenced by both T1 and T2 relaxation time; there is a close relationship between the signal intensity of brain tumors on T2-weighted images and the degree of contrast enhancement on FLAIR sequences. When tumors have higher signal intensity than normal cortex on T2-weighted images, additional postcontrast FLAIR imaging may improve their depiction.     

急性脊髓型减压病的MRI诊断

目的 描述急性脊髓型减压病的MRI表现,提高对该病的认识水平.方法 对5例有明确潜水作业史,且违反减压规定、快速出水后短时内出现完全或不完全性脊髓损害症状,以感觉障碍和大小便失禁为主要临床表现,经临床综合确诊为急性脊髓型减压病的患者的MRI表现进行回顾性分析.结果 5例均见脊髓空泡征及T2 WI弥漫性略高信号,在T1 WI上呈等信号3例,略高信号和略低信号各1例.3例见猫头鹰眼征,2例见多发腔隙性病灶,T2 WI脊髓内条状低信号及T1 WI马尾略高信号各1例.结论 急性脊髓型减压病的MRI表现具有一定特点,结合潜水并违规减压史和临床表现容易作出准确诊断.