Jugular venous thrombosis: MR imaging

Magnetic resonance (MR) imaging of jugular venous thrombosis was investigated in three patients who had symptoms suggestive of this condition; the diagnosis was later confirmed by computed tomography, by venography, and clinically. Bright intraluminal signal intensity was seen throughout the course of the affected jugular vein on MR images in all three patients, in sharp contrast to the lack of signal from the corresponding site in the uninvolved venous system. Temporal changes in signal intensity from the acute to subacute stage of thrombosis were evaluated for one patient. A relative increase in signal intensity for the subacute phase was believed to be related to a decrease in the T1 relaxation time. MR may be the imaging modality of choice in the investigation of venous thrombosis.     

Retrograde flow in the left inferior petrosal sinus and blood steal of the cavernous sinus associated with central vein stenosis: MR angiographic findings

BACKGROUND AND PURPOSE: We attempted to identify the cause of abnormal venous flow seen during arterial MR angiography in the inferior petrosal sinus by use of in three female patients (aged 51, 48, and 70 years, respectively). METHODS: Arterial 3D time-of-flight MR angiography was performed with a tilted optimized nonsaturating excitation pulse sequence (TR/TE, 31/7; flip angle, 20 degrees; section thickness, 65 mm; effective thickness, 1 mm; number of sections, 1 to 2); no magnetization transfer pulse sequence was used. Contrast-enhanced 3D MR angiography of the neck was performed with a 3D fast low-angle shot pulse sequence (TR/TE, 4.6/1.8; flip angle, 40 to 45 degrees; section thickness, 80 mm; intersection gap, 1.5 mm; acquisition matrix, 180 x 256; acquisition time, 27 s) on a system with a whole-body coil. RESULTS: In all three patients, 3D time-of-flight MR angiography revealed abnormal vascular signal originating from the left cavernous sinus, continuing through the inferior petrosal sinus, and ending in the proximal internal jugular vein at the jugular bulb level. Abnormal vascular signal at the jugular bulb, sluggish flow and flow-related enhancement in the left internal jugular vein, and signal void in the contralateral jugular vein were noted. Contrast-enhanced delayed-phase MR angiography showed stenosis in the left brachiocephalic vein in all patients. CONCLUSION: High signal intensity noted at the inferior petrosal sinus resulted from retrograde flow. Retrograde flow was due to blood stealing from the internal jugular vein toward the cavernous sinus because of venous stenosis in the brachiocephalic vein.     

Dural sinus thrombosis: study using intermediate field strength MR imaging

The magnetic resonance (MR) images of six patients with thrombosis of a dural sinus were reviewed. The diagnosis had been verified by computed tomographic scans in three patients and arteriograms in two; in the sixth patient, only MR imaging was used to confirm the clinical syndrome. In all patients, high-intensity signal was seen from the thrombus within the affected dural sinus on all echoes. This persistent signal intensity allowed intravascular clot to be distinguished from normal causes of increased signal such as flow-related enhancement (entry phenomenon) and even-echo rephasing. MR imaging demonstrated the cause of the thrombosis in three patients: two were secondary to adjacent tumors, and one was secondary to unsuspected mastoiditis. Complications such as infarction were also demonstrated. Using MR imaging, one can easily and safely diagnose thrombosis of a dural sinus. MR should be the imaging method of choice in patients suspected of having thrombosis of a dural sinus.     

Postpartum superior sagittal,left transverse sinus and right internal jugular vein thrombosis with left parietal infarct: A case report

Cerebral venous sinus thrombosis is a rarely occurring condition. Pregnancy and postpartum are both known risk factors for cerebral venous sinus thrombosis. Early detection and treatment are critical, as CVST can be potentially life-threatening. Here, we present a case of a patient who developed left transverse and superior sagittal sinus thrombosis 15 days after normal vaginal delivery. The patient presented to the emergency department with complaints of irritability and an altered state of consciousness for two days. The patient also developed seizures extending from the lower limb to the upper body. Laboratory investigations revealed abnormalities in the complete blood count report and urine complete examination. The patient''s coagulation profile was totally abnormal, indicating a presence of a thrombus. All the other diagnostic techniques, including Electrocardiogram, Carotid Doppler Scan, and Ultrasound abdomen, revealed no findings. However, Magnetic resonance venography + Magnetic resonance imaging showed partial superior sagittal sinus thrombosis in the anterior and upper parietal regions, right internal jugular vein thrombosis, and left transverse thrombosis with associated left parietal infarcts. The presence of thrombosis in sinuses and jugular vein resulted in seizures, altered state of consciousness, and other associated symptoms. The patient was treated with sodium valproate, heparin, and other medications accordingly. The above-mentioned case was unique due to the involvement of unusual sinuses (transverse sinus) as previous studies have only reported cases of thrombus presence in the superior sagittal sinus. This case study will discuss patient diagnosis and management with Heparin and Diazepam to stop altered state of consciousness and seizures in females.     

Dural sinus thrombosis

Summary Magnetic resonance imaging has been reported to have advantages over conventional angiography in the diagnosis of dural sinus thrombosis. A case report is presented describing the application of MR techniques including MR angiography, to diagnose and monitor therapy for dural sinus thrombosis.     

Rhinocerebral mucormycosis: MR manifestations

Magnetic resonance (MR) examinations of three patients with rhinocerebral mucormycosis are reviewed. The clinical course is outlined and the MR characteristics are analyzed in light of the known pathology. The major MR findings include sinus and orbital disease followed by deep facial extension. Involvement of basal portions of the hemispheres, brain stem, and hypothalamus occurred rapidly following ipsilateral facial or orbital invasion in all three cases. Regions of intracerebral inflammation were hyperintense compared with normal parenchyma on T2-weighted and proton density-weighted images. Septic cavernous sinus and internal carotid artery thrombosis was diagnosed by MR in one case. Magnetic resonance demonstrated partial resolution of intracerebral abnormalities that accompanied clinical improvement in the one surviving patient.     

Venous thrombosis: clinical and experimental MR imaging

Five venous thrombi were induced in the external jugular veins of three laboratory dogs, and were repeatedly imaged over 3 weeks using a 0.35-T magnetic resonance (MR) imager. MR magnitude and phase images, T1 and T2 relaxation times, venography, and histologic sections of these thrombi were evaluated to determine the changes in appearance on MR images with time. Venous thrombi appeared hyperintense compared with muscle on both relatively T1- and T2-weighted spin-echo sequences regardless of the age of the clot. Organization of the thrombus beyond 1 week was manifested as increased prominence of flow signal void in and around the clot. Distinction between intraluminal thrombus and flow-related artifacts was aided by phase image reconstruction. Nineteen venous thrombi locations in 13 patients revealed an MR appearance similar to that of the experimental animal model. Three patients (six thrombi locations) had serial examinations over 4 weeks. No significant change in thrombus signal characteristics was noted with time. It is concluded that MR imaging at 0.35 T cannot be used to predict the age of thrombus (up to 3 weeks) but may be helpful in following its resolution.     

MR findings in rhinocerebral mucormycosis

A case of rhinocerebral mucormycosis evaluated by magnetic resonance (MR) imaging is presented, with inflammatory changes in the paranasal sinuses and orbit. Extension of the infection into the cavernous sinus, with cavernous sinus thrombosis and internal carotid artery narrowing, was well demonstrated on pre- and postgadolinium MR images. Infarctions in the anterior choroidal artery distribution suggested intracranial invasion of basal arteries, and watershed distribution infarctions attested to the tenuousness of flow through a narrowed cavernous carotid artery. Magnetic resonance effectively demonstrated the wide array of findings possible in rhinoorbitocerebral mucormycosis.     

Cerebral MR venography in children: comparison of 2D time-of-flight and gadolinium-enhanced 3D gradient-echo techniques

PURPOSE: To prospectively compare two-dimensional (2D) time-of-flight cerebral magnetic resonance (MR) venography with gadolinium-enhanced three-dimensional (3D) gradient-echo cerebral MR venography in children. MATERIALS AND METHODS: This investigation had investigational review board approval and was Health Insurance Portability and Accountability Act compliant; parental informed consent was obtained. Thirty-seven patients (20 boys, 17 girls) who ranged in age from 4 days to 15 years underwent 2D and 3D MR venography. Two pediatric neuroradiologists compared the visibility of the superior sagittal, straight, transverse, and sigmoid sinuses and the internal jugular veins on images obtained with the two sequences. RESULTS: In 17 (46%) of the 37 patients, the sequences were equivalent in terms of their depiction of venous anatomy. In 19 (51%) of the 37 patients, 3D MR venography was superior to 2D MR venography. Suboptimal enhancement of veins occurred in one (3%) patient at 3D MR venography. Venous anomalies suggested at 2D MR venography but not present at 3D MR venography included flow gaps in the nondominant transverse sinuses of four patients, unilateral transverse sinus atresia in eight, and a narrowed superior sagittal sinus in two. Two-dimensional MR venography results failed to reveal a persistent falcine sinus associated with straight sinus atresia in one patient and suggested transverse sinus thrombosis in two patients in whom 3D MR venography results were normal. Additionally, the extent of dural thrombosis was overestimated at 2D MR venography in one patient. As compared with 3D MR venography, 2D MR venography failed to reveal sigmoid sinus stenosis in one patient and poorly depicted posterior fossa dural sinus anatomy in two patients with dural arteriovenous fistula. CONCLUSION: Three-dimensional MR venography is often superior to 2D MR venography in the delineation of major cerebral venous structures in children. Most of the artifactual loss of vascular signal seen with the use of 2D MR venography occurred in nondominant transverse sinuses.     

Gadolinium-enhanced MR angiography

Experience in three patients (one each with meningioma, pineal tumor, and prominent jugular bulb) illustrates that magnetic resonance (MR) angiography can benefit from the administration of gadolinium diethylenetriaminepentaacetic acid. Data were acquired with a three-dimensional velocity-compensated (fast imaging with steady-state precession) sequence. MR angiograms were obtained with a ray projection algorithm by using maximum intensity values. Portions of the vascular anatomy--particularly venous structures and smaller arteries--were better portrayed on the postcontrast than on the precontrast angiograms. Enhancing lesions were also seen on the projection images. Enhancement of dura and extracranial tissues (sinus and nasal mucosa) can obscure vascular detail.     

MRI联合磁共振静脉成像诊断脑静脉窦血栓形成的价值

目的:探讨MRI及磁共振静脉成像(MRV)对脑静脉窦血栓形成的诊断价值.方法:回顾性分析37例DSA确诊脑静脉窦血栓形成患者的临床资料及影像表现.37例中有30例行常规MRI检查,29例行MRV(2D TOF)检查.结果:30例常规MRI检查中28例静脉窦有异常信号,其中26例MRI表现为静脉窦T1WI、T2WI高信号,2例T1WI等信号、T2WI低信号,并部分伴有脑组织梗死、出血.29例MRV检查均发现静脉窦充盈缺损或中断.结论:MRI与MRV结合对诊断脑静脉窦血栓形成具有高度敏感性,是诊断静脉窦血栓形成的首选检查方法.     

Deep venous thrombosis evaluation with limited-flip-angle, gradient- refocused MR imaging: preliminary experience

Sixteen patients (17 lower extremities) were prospectively examined with venography and limited-flip-angle, gradient-refocused magnetic resonance (MR) imaging for the presence or absence of deep venous thrombosis. Thrombosed vessels showed decreased-to-absent signal intensity, while patent vessels had high signal intensity. In 16 of 17 extremities, MR images allowed accurate detection and localization of the thrombi found with venography. In the remaining extremity, MR imaging allowed correct identification of thrombus in the iliac and femoral veins but incorrectly demonstrated clot in the calf and popliteal veins. MR imaging with limited-flip-angle, gradient-refocused pulse sequences appears to be a sensitive, noninvasive means of detecting deep venous thrombosis.     

MR imaging of portal venous thrombosis: correlation with CT and sonography

Fourteen patients with portal venous thrombosis (PVT) diagnosed by CT and/or sonography were studied with MR. Three of the 14 had portal hypertension. The MR findings were compared with those of eight patients with portal hypertension, but without CT or sonographic evidence of PVT. MR imaging showed portal venous thrombosis in all 14 PVT cases. Intraluminal thrombi of less than 5 weeks duration appeared markedly hyperintense relative to liver and muscle on both T1- and T2-weighted images. Older thrombi appeared hyperintense relative to liver and muscle in eight of 11 cases, but only on T2-weighted images. MR showed thrombi in 11% more portal vessels than did CT (MR = 30, CT = 27) and in 28% more vessels than did sonography (MR = 32, sonography = 25). MR also showed 24% more collateral vessels than did CT (MR = 31, CT = 25) and 50% more vessels than did sonography (MR = 33, sonography = 22). Third-echo images (echo time = 96 msec, repetition time = 1500-2150 msec) verified the presence of venous thrombi in 28 (93%) of 30 PVT vessels, and they differentiated flow-related intravascular signal from true thrombi in six (17%) of 36 portal hypertension vessels. We conclude that MR is a valuable tool for imaging portal vein thrombosis. MR is a good substitute for CT and can be more informative than sonography.     

颅内静脉窦血栓形成的早期MRI诊断及病理基础

目的:研究颅内静脉窦血栓形成(CVST)的MR表现及其病理基础,旨在提高早期诊断水平.方法:回顾分析经临床和影像学方法确诊的11例CVST患者.MR检查技术包括平扫、增强扫描及MRV;其中4例行CT平扫检查;3例行DSA检查.结果:11例CVST累及上矢状窦5例,横窦1例,乙状窦1例,直窦1例,上矢状窦及横窦及乙状窦联合受累2例,横窦及乙状窦联合受累1例.CVST的直接征象:急性期血栓3例,T1 WI呈等信号或等高混杂信号,T2 WI呈低信号,周围可见稍高信号的环,为增厚的硬膜;亚急性期血栓8例,T1 WI及T2 WI均以高信号为主.增强扫描受累静脉窦可见空"三角"征或"充盈缺损"征.MRV可显示受累静脉窦不显影或者充盈缺损形成.CVST的继发脑损害包括脑肿胀、出血及梗死等.结论:磁共振检查对CVST的早期诊断具有重要价值.对于T2 WI呈低信号的急性期血栓,应仔细观察围是否有较高信号的环形改变,进一步行增强扫描结合MRV检查可作出早期准确的诊断.     

Central thrombi in pulmonary arterial hypertension detected by MR imaging

Differentiation of thrombi from slow flow in the pulmonary arteries, sometimes observed in the presence of pulmonary arterial hypertension, can be equivocal. Magnetic resonance (MR) imaging was performed in a patient with chronic pulmonary thromboembolism and pulmonary arterial hypertension using an electrocardiographically gated technique that allowed visualization of the pulmonary arteries at the end of diastole and multiple times during systole. These images were compared with those of a patient with primary pulmonary hypertension and those of healthy subjects. Thrombi were discrete structures, seen throughout the cardiac cycle on both the first and second spin-echo images, and decreased in signal intensity on the second image. Slow flow increased in signal intensity and changed in structure during the cardiac cycle and was seen best on the second image. MR may play an important role in excluding large central thrombi as the cause of pulmonary arterial hypertension. It is a noninvasive method for defining pulmonary arterial wall thickness and for direct visualization of chronic pulmonary thrombus.     

Diagnosis of femoropopliteal venous thrombosis with MR imaging: a comparison of four MR pulse sequences

In a prospective study, MR images were evaluated in seven patients with femoropopliteal venous thrombosis with symptoms of less than 5 days duration. T1-weighted (600/25 [TR/TE]), intermediate (2000/30), and T2-weighted (2000/100) spin-echo series and a gradient-recalled acquisition in the steady state (GRASS) series were compared. Using venography as the standard for diagnosis, we found GRASS to be the most sensitive of the MR techniques, showing thrombi in all patients. It provided good contrast between the low-intensity thrombus and high-intensity flowing blood and also between thrombus and intermediate- or high-intensity perivascular tissues. The T1-weighted series was the least sensitive technique. All thrombi showed heterogeneity in the transaxial image with differences in signal between the peripheral and central regions. A higher intensity signal in the center than in the periphery at some level of the thrombus was found in six of seven T2-weighted or GRASS images. Heterogeneity in the signal intensity was more frequent in distal portions of thrombi, whereas the most proximal extent was homogeneous in appearance in six of seven cases. The heterogeneous appearance may be related to the greater age of the distal thrombus, because deep venous thrombi are known to begin in the calf and extend proximally over time. We conclude, on the basis of our experience with a small number of patients, that the GRASS MR technique is more sensitive for detecting acute deep venous thrombosis than T1-weighted, intermediate, and T2-weighted MR images.     

MR imaging of cardiac thrombi

This retrospective study of 10 magnetic resonance (MR) examinations in patients with cardiac thrombi (eight in left ventricle and two in right atrium) was performed to assess the ability of MR for demonstrating cardiac thrombi and describe the appearance of cardiac thrombi using the spin echo technique. Cardiac thrombi usually had higher signal intensity than the normal myocardium on MR imaging, especially on the second echo (TE of 56 or 60 ms) image. Differentiation between cardiac thrombus and intracardiac signal resulting from slowly flowing blood was possible based on different signal intensity changes using various techniques. In conclusion, MI imaging constitutes another noninvasive modality for the detection of cardiac thrombus. Further work is needed to determine its accuracy compared with that of two-dimensional echocardiography.     

Magnetic resonance imaging of the jugular foramen

The jugular foramen in normal volunteers was studied with 1.5 T magnetic resonance (MR) systems in 3-mm-thick head- and surface-coil images. Anatomic sections through cadaver heads were correlated with the MR images to identify the jugular bulb and the course of cranial nerves IX-XI. Sagittal images were more useful than coronal or axial to show the course of these nerves through the skull base. MR demonstrates the anatomic relations of the jugular foramen (except its osseous margins) such that its primary use in evaluating this region can be anticipated.     

Emergency MR imaging of the central nervous system

Magnetic resonance (MR) of the central nervous system has few, but important indications for use in the acute setting. This report reviews the few true current clinical indications for emergency MR imaging, including ruling out spinal cord compression, vascular dissection or dural venous sinus thrombosis. Possible indications for emergency MR, including evaluation of acute stroke symptomatology, potential meningoencephalitis or vasculitis, are also presented. Future applications for MR, including MR angiography in the setting of acute subarachnoid hemorrhage and spectroscopy in acute ischemia, are mentioned.     

Detection of aortic arch thrombus using MR imaging

Three patients with peripheral embolization and negative echocardiographic examinations were studied with MR imaging. Magnetic resonance imaging detected aortic arch thrombi in the absence of aortic aneurysm, dissection, or ulcerated plaques. By combining spin echo and cine MR sequences, MR enabled us to characterize and contrast intravascular mural thrombi reliably without application of contrast media. Thus we are assisted in the identification of patients at risk for embolization from an often overlooked source: the thoracic aorta.