Neuro-Behcet''s disease: diffusion MR imaging and proton MR spectroscopy

We herein report the case of a 53-year-old woman with Behcet's disease and an acute T2-hyperintense lesion in left side of the pons. Echo-planar "trace" diffusion MR imaging revealed high signal intensity changes at the lesion site on b = 1000 s/mm(2) images, initially suggesting restricted diffusion. On corresponding apparent diffusion coefficient maps, however, the lesion had high signal intensity and high apparent diffusion coefficient values (1.22 x 10(-3) mm(2)/s), compared with the contralateral normal side of the pons (0.86 x 10(-3) mm(2)/s) and compared with the normal temporal white matter (0.80 x 10(-3) mm(2)/s). This was consistent with the presence of increased diffusion, hence vasogenic edema. Proton MR spectroscopy excluded acute infarction. This particular pattern (high signal intensity on b = 1000 s/mm(2) images in association with high apparent diffusion coefficient values) likely represented the acute inflammatory process associated with disrupted brain-blood barrier in the fulminant form of neuro-Behcet's disease. Follow-up examinations 相似文献   

Craniocervical artery dissection: MR imaging and MR angiographic findings

Dissection of the carotid and vertebral arteries is a not so uncommon cause of stroke and has to be considered as a differential diagnosis especially in younger patients. Therapeutic and prognostic implications are different from those in extracranial atherosclerotic disease. Dissection results from hemorrhage into the vessel wall usually between the layers of the media. Digital subtraction angiography (DSA) depicts the resulting luminal compromise that may reveal some typical, but not specific, findings. The same is true for non-invasive angiographic techniques such as time-of-flight magnetic resonance angiography (MRA) and computed tomography angiography (CTA), which have shown accurate results compared with DSA. The main advantage of these techniques is the direct visualization of the vessel wall confirming the intramural hematoma. This is achieved best with MR imaging due to the high signal of blood degradation products on T1- and T2-weighted images. Therefore, MRI in combination with MRA is presently the method of choice for initial diagnosis and follow-up of craniocervical artery dissection (CCAD). In some questionable cases, CTA is a non-invasive alternative that is independent of flow phenomena. Received: 4 May 1998; Revision received: 8 September 1998; Accepted: 10 November 1998     

Pisotriquetral joint: assessment with MR imaging and MR arthrography

PURPOSE: To evaluate magnetic resonance (MR) imaging and MR arthrographic findings in the pisotriquetral joint (PTJ) and their contribution to assessment of PTJ osteoarthritis. MATERIALS AND METHODS: Images of 22 fresh human cadaveric PTJs were obtained with both conventional and arthrographic MR techniques. The MR appearances of all intraarticular and periarticular structures were analyzed and correlated with anatomic slices. Two readers graded visibility of anatomic structures and severity of joint abnormalities. Differences in the visibility ratings at standard MR imaging and at MR arthrography were calculated. Association between the type of pisiform insertion of ligament or muscle with cartilaginous abnormalities of the PTJ was assessed. The association between cartilaginous lesions and osteoarthritic changes was calculated. RESULTS: The tendon sheath, the fibrous capsule, and cartilaginous surfaces were better visualized at MR arthrography than at MR imaging. Pisohamate and pisometacarpal ligaments were slightly better seen on MR arthrograms. Tendons, muscles, and retinacular structures were well demonstrated at both conventional MR and MR arthrography. Cartilaginous lesions and osteophytes were easily identified and were detected more often in the pisiform bone than in the triquetral bone. Communication of the PTJ with the radiocarpal joint was noted in 18 (82%) of 22 wrists. CONCLUSION: MR imaging and/or MR arthrography allows visualization of all anatomic structures of the PTJ. MR arthrography improves visualization of findings of osteoarthritis.     

MRI和MRA对烟雾病的诊断价值

目的：评价ＭＲＩ和ＭＲ血管成像（ＭＲＡ）在烟雾病中的诊断价值。材料与方法：回顾性分析２３例烟雾病患者的ＭＲＩ和ＭＲＡ资料，ＭＲＡ采用三维时间飞跃法。结果：２３例患者ＭＲＡ图像均有不同程度的颈内动脉分叉处的血管狭窄／闭塞，１８例基底节区异常网状的血管和１４例软脑膜侧支循环血管显示清晰。ＭＲＩ上显示了所有患者的脑实质改变和１５例颈内动脉分叉处的血管狭窄／闭塞改变，所有患者根据其ＭＲ上脑血管的改变均可做出正确的诊断。结论：ＭＲＡ结合ＭＲＩ能对烟雾病患者做出正确的诊断和较准确的分期，同时可用于烟雾病患者的随访检查和术后复查。     

Marchiafava-Bignami disease: longitudinal MR imaging and MR spectroscopy study

A case of Marchiafava-Bignami disease was serially evaluated with MR imaging and MR spectroscopy at 1, 2, 4, and 11 months after the onset of symptoms. The first MR imaging study showed extensive abnormal signal intensity of the corpus callosum without macroscopic changes; a diagnosis of Marchiafava-Bignami disease was made, and vitamin therapy was initiated. Follow-up studies showed progressive reduction of signal intensity abnormalities and residual callosal atrophy. MR spectroscopy revealed progressive reduction of the N-acetylaspartate:creatine ratio, with partial recovery in the last study, and a normalization of the choline:creatine ratio, which was initially slightly increased. Lactate was detectable during the subacute phase and was replaced by lipids after 4 months. This study confirmed the role of MR imaging in diagnosing Marchiafava-Bignami disease and particularly the value of MR spectroscopy in focusing the pathogenesis of the disease, monitoring its evolution and changes related to therapy.     

脂肪肝：MRI影像表现及MRI序列选择

目的：选择评估脂肪肝的MRI序列和认识脂肪肝的MRI影像表现以帮助鉴别诊断,方法：18例脂肪肝病人进行了肝脏平扫和增强MRI,采用屏气同,反相位T1加权梯度回波序列,2D FLASH加脂肪抑制T1WI以及HASTE T2WI。结论：18例肝脂肪变中伴有7例肝癌,2例血管瘤,1例囊肿,5例肝硬化;弥漫型脂肪浸润6例,局灶型脂肪浸润12例,脂肪肝影像表现,T1WI同相位表现为稍高或等信号,反相位或加压脂T1WI呈低信号;T2WI呈稍高或等信号,部分脂肪肝伴脂内肿块在反相位或加压脂TWI上可见低信号肿块周边全周或部分环状高信号带,在增强MRI上无明显强化,有时见少量小血管进入其内,结论：同与反相位MRI能较好鉴别诊断脂肪肝,两者互补,缺一不可,可避免脂肪肝的误诊或汤诊。建议对疑有脂肪肝患者行同,反相位T1加权MRI扫描。     

Subtraction MR Venography Acquired from Time-Resolved Contrast-Enhanced MR Angiography: Comparison with Phase-Contrast MR Venography and Single-Phase Contrast-Enhanced MR Venography

ObjectiveTo evaluate the image characteristics of subtraction magnetic resonance venography (SMRV) from time-resolved contrast-enhanced MR angiography (TRMRA) compared with phase-contrast MR venography (PCMRV) and single-phase contrast-enhanced MR venography (CEMRV).ResultsSingle-phase contrast-enhanced MR venography showed better image quality (median score 4 in both reviewers) than did the other two MRVs (p < 0.001), whereas SMRV (median score 3 in both reviewers) and PCMRV (median score 3 in both reviewers) had similar image quality (p ≥ 0.951). SMRV (median score 0 in both reviewers) suppressed arterial signal better than did the other MRVs (median score 1 in CEMRV, median score 2 in PCMRV, both reviewers) (p < 0.001). The dural sinus score of SMRV (median and interquartile range [IQR] 48, 43-50 for reviewer 1, 47, 43-49 for reviewer 2) was significantly higher than for PCMRV (median and IQR 31, 25-34 for reviewer 1, 30, 23-32 for reviewer 2) (p < 0.01) and did not differ from that of CEMRV (median and IQR 50, 47-52 for reviewer 1, 49, 45-51 for reviewer 2) (p = 0.146 in reviewer 1 and 0.123 in reviewer 2). The SNR and CNR of SMRV (median and IQR 104.5, 83.1-121.2 and 104.1, 74.9-120.5, respectively) were between those of CEMRV (median and IQR 150.3, 111-182.6 and 148.4, 108-178.2) and PCMRV (median and IQR 59.4, 49.2-74.9 and 53.6, 43.8-69.2).ConclusionSubtraction magnetic resonance venography is a promising MRV method, with acceptable image quality and good arterial suppression.     

MR imaging of liposarcomas: correlation of MR features and histology

The magnetic resonance (MR) imaging features of liposarcoma were correlated with histology in 15 patients. The MR findings for liposarcoma were not specific. The six myxoid liposarcomas and two atypical lipomatous tumors, however, had distinctive MR features, i.e., nodular masses of slightly heterogeneous intermediate to high signal intensity (SI), intermingled with high SI septa on T1-weighted images. The T2-weighted images demonstrated the relative reversal of these regional SI characteristics. Additionally, MR correctly identified the presence of fat in all eight cases in which it was pathologically present. The fat in two atypical lipomatous tumors was inseparable on MR from the subcutaneous fat. Magnetic resonance appears useful for preoperative staging and follow-up studies of liposarcomas. It may be helpful in identifying patients with myxoid liposarcoma and atypical lipomatous tumors who have longer survival times.     

Prospective evaluation of pancreatic tumors: accuracy of MR imaging with MR cholangiopancreatography and MR angiography

PURPOSE: To prospectively assess accuracy of magnetic resonance (MR) imaging, MR cholangiopancreatography (MRCP), and MR angiography in patients suspected of having pancreatic tumors. MATERIALS AND METHODS: Sixty-six patients suspected of having pancreatic tumors underwent MR imaging (unenhanced and contrast material-enhanced MR, MRCP, and contrast-enhanced MR angiography). Two blinded readers prospectively analyzed the images by consensus, and results were correlated with surgery, biopsy, or follow-up findings. Results were tabulated in two-by-two tables. RESULTS: MR assessment of pancreatic lesion status (differentiation of benign vs malignant) resulted in 60 correct diagnoses (accuracy, 91%), and six (10%) false diagnoses. Among histologically proved malignant tumors, MR imaging yielded correct diagnoses in 42 of 44 patients (sensitivity, 95%; 95% CI: 85%, 99%), whereas 18 of 22 patients with benign findings were classified correctly. At MR imaging, findings in four patients with chronic pancreatitis were wrongly categorized as malignant tumors (specificity, 82%; 95% CI: 60%, 95%), and in one patient, a distal common bile duct carcinoma was not detected. In no patient with pancreatic adenocarcinoma was this tumor misdiagnosed as benign. In patients with malignant tumors who underwent resection, local-regional tumor growth and vascular infiltration were accurately classified in 89% and 94%, respectively. MR imaging depicted histologically proved synchronous hepatic metastases in 82%. The positive and negative predictive values for cancer nonresectability were 90% and 83%, respectively, and the accuracy, sensitivity, and specificity were 85%, 69%, and 95%, respectively. CONCLUSION: Unenhanced and contrast-enhanced MR imaging with MRCP and MR angiography offers potential as a noninvasive tool for assessment of patients suspected of having pancreatic tumors.     

Pantothenate kinase-associated neurodegeneration: MR imaging,proton MR spectroscopy,and diffusion MR imaging findings

We herein report the case of a 15-year-old male patient with pantothenate kinase-associated neurodegeneration. The classic "eye-of-the-tiger" appearance was initially present on the globus pallidi on T2-weighted MR images and had disappeared by the time of the 10-month follow-up examination. Fluid-attenuated inversion recovery images revealed marked hypointensity in the globus pallidi and dentate nuclei and high signal intensity changes in the deep cerebral white matter. Proton MR spectroscopy revealed markedly decreased N-acetylaspartate in the globus pallidi, associated with decreased N-acetylaspartate and increased myoinositol in the deep cerebral white matter. Diffusion MR images (b=1000 s/mm(2)) were negative (normal appearing) for deep cerebral white matter lesions, whereas apparent diffusion coefficient values were slightly increased (1.08-1.12 x 10(-3) mm(2)/s), compared with the apparent diffusion coefficient values from the normal white matter regions. Apparent diffusion coefficient values in the globus pallidi were lower than those in the unaffected thalamus.     

MR相位对比法和形态体积分析法评价心室功能的比较研究

目的探讨相位对比法MR和形态体积分析法MR成像技术在评价心室功能中的临床应用价值。方法应用相位对比法MR(phasecontrastmagneticresonanceimaging,PCMRI)和形态体积分析法电影MRI(stereologicalcinemagneticresonanceimaging,SCMRI)分别对12例健康成年人和46例心脏病患者进行检查。首先应用SCMRI行心脏左、右室短轴电影成像,分别描记左、右室心内、外膜界面,测出左右心室舒张末期容量(EDV)、收缩末期容量(ESV)、每搏输出量(SV)、射血分数(EF)等指标;再应用PCMRI和流量分析软件分别在主动脉瓣上和肺动脉瓣上水平测得1个心动周期内的前向血流,获得SV值,并将2种方法的测量结果进行比较;同时对正常志愿者与患者组、正常志愿者组左、右两侧心室,以及PCMRI法在主动脉瓣上和肺动脉瓣上水平测得的左右心室SV均值进行比较。结果(1)PCMRI与SCMRI法所测正常志愿者左、右心室的SV相关良好,相关系数分别为090和087,2种方法测得的SV均值差异无统计学意义(P>005)。(2)患者组2种MRI测量方法所得左室SV的相关系数为085,SV均值比较差异无统计学意义(P>005),应用PCMRI法在主动脉瓣上水平测得正常人与患者组的SV均值,差异有统计学意义(P<005)。结论PCMRI与SCMRI法相比,对心室每搏输出量(SV)测量准确,相关性好,重复性高,加     

Biliary obstruction: findings at MR cholangiography and cross-sectional MR imaging.

Twenty-two patients with malignant biliary obstruction and 21 patients with suspected obstruction of biliary-enteric anastomoses were evaluated over a 12-month period with magnetic resonance (MR) cholangiography and cross-sectional MR imaging. In patients with malignant obstruction, MR cholangiography helped accurately determine the status of the biliary ductal system by identifying the exact location and extent of the obstruction and the severity of duct dilatation. In so doing, MR cholangiography helped determine whether percutaneous transhepatic cholangiography with antegrade stent placement or retrograde cholangiography with stent placement constituted the more suitable treatment. Cross-sectional MR imaging was necessary to identify the organ of tumor origin, define the tumor margins, and determine the stage of disease. This information helped evaluate the appropriateness of curative surgical therapy versus palliative drainage procedures. In patients with biliary-enteric anastomoses, MR cholangiography clearly depicted the site of the anastomosis and demonstrated the status of the intrahepatic ducts, thereby helping determine which patients would benefit from undergoing antegrade duct cannulation with a drainage procedure or perhaps balloon dilation. In some of these patients, MR cholangiography was sufficient to help plan therapeutic intervention. MR cholangiography also demonstrates the presence and size of biliary stones and associated findings such as intraductal tumor growth. In addition, MR cholangiography may obviate retrograde cholangiography, which can be technically difficult to perform.     

Acute chest pain: The role of MR imaging and MR angiography

MR imaging (MRI) and MR angiography (MRA) have gained a high level of diagnostic accuracy in cardiovascular disease. MRI in cardiac disease has been established as the non-invasive standard of reference in many pathologies. However, in acute chest pain the situation is somewhat special since many of the patients presenting in the emergency department suffer from potentially life-threatening disease including acute coronary syndrome, pulmonary embolism, and acute aortic syndrome. Those patients need a fast and definitive evaluation under continuous monitoring of vital parameters. Due to those requirements MRI seems to be less suitable compared to X-ray coronary angiography and multislice computed tomography angiography (CTA). However, MRI allows for a comprehensive assessment of all clinically stable patients providing unique information on the cardiovascular system including ischemia, inflammation and function. Furthermore, MRI and MRA are considered the method of choice in patients with contraindications to CTA and for regular follow-up in known aortic disease. This review addresses specific features of MRI and MRA for different cardiovascular conditions presenting with acute chest pain.     

MR泌尿系成像的技术和应用

目的：估价ＭＲ泌尿系成像的技术和应用价值。材料与方法：用重Ｔ２加权快速自旋回波（ＦＳＥ）序列和脂肪抑制技术作ＭＲ泌尿系成像９５例。所有图像均作最大信号强度投影（ＭＩＰ）处理。结果：９５例均清楚显示肾实质和泌尿系集合系统高质量的影像。７１例阳性，２４例阴性。阳性病种包括：肾癌７例，肾囊肿１７例，肾脓肿１例，肾盂癌４例，肾盏血块１例，肾结核７例，输尿管癌６例，输尿管结石３例，狭窄２例，非梗阻性输尿管扩张和膀胱癌各４例，前列腺病３例，以及各种先天异常等１２例。结论：ＭＲ泌尿系成像是一种很可靠的、非侵袭性的检查方法，它不用造影剂，可避免碘副反应。在形态上，它能较好地显示泌尿系的解剖结构，补充了泌尿系影像学检查方法，是技术上的一大进步。     

MR portography: Preliminary comparison with CT portography and conventional MR imaging

Magnetic resonance (MR) imaging with arterial portography (MRAP) was compared with computed tomography with arterial portography (CTAP) and conventional MR imaging for preoperative evaluation of hepatic masses in eight patients (nine studies). Twenty contiguous, 10-mm-thick-section CTAP images were obtained. MR imaging included T1- and T2-weighted spin-echo and fast multiplanar SPGR (spoiled gradient-recalled acquisition in the steady state) techniques. For MRAP, 0.1 mmol/kg gadopentetate dimeglumine was injected into the superior mesenteric artery. Portographic-phase, 8-mm-thick-section, axial SPGR images were first obtained, followed by “systemic phase” SPGR images. Lesions were seen best on the portographic-phase MRAP images and were less conspicuous on the systemic-phase MRAP, CTAP and conventional MR images. Of 19 visualized lesions, 18 were seen with MRAP; however; five subcentimeter lesions seen with MRAP were not seen with conventional MR imaging or CTAP. Systemic recirculation of iodinated contrast material from the bolus and from previous angiography is a potential limitation of CTAP. For both CTAP and MRAP, optimal results are expected if all images are obtained during a single breath hold, within seconds of the onset of contrast agent administration.     

Cervical MR imaging in postural headache: MR signs and pathophysiological implications

BACKGROUND AND PURPOSE: Postural headache most often occurs after lumbar puncture as post-lumbar puncture headache (PLPH) or, rarely, spontaneously as spontaneous intracranial hypotension headache (SIHH). In this prospective study, we used spinal MR imaging to determine the findings that would assist in the diagnosis of PLPH and SIHH and that would further our pathophysiological understanding of postural headache. METHODS: The study group consisted of 15 healthy volunteers and 20 patients with postural headache: nine with SIHH and 11 with PLPH. The craniocervical junction and the cervical spine were studied using T2-weighted fast spin-echo and T1-weighted spin-echo sequences in the axial and sagittal planes. Follow-up studies were performed in 13 patients. RESULTS: Dilatation of the anterior internal vertebral venous plexus was the most constant finding, present in 17 (85%) of 20 patients with postural headache. Spinal hygromas, whose location as subdural or epidural could not be exactly determined, were present in 14 patients (70%). A focal fluid collection was detected in the retrospinal region at the C1-C2 level in six patients with SIHH and in four patients with PLPH (50%). Tonsillar descent was detected in only one patient, and subtentorial hygroma in five patients. No abnormalities were found in the volunteers. CONCLUSION: The MR signs of dilatation of the venous plexus, presence of spinal hygromas, and presence of retrospinal fluid collections can help to establish the diagnosis of intracranial hypotension. They are probably the result of decreased CSF volume, with the retrospinal fluid collections being a transudate from the venous plexus rather than frank extravasation. Resolution of these signs parallels resolution of the headache.