Preoperative evaluation of carotid artery stenosis: comparison of contrast-enhanced MR angiography and duplex sonography with digital subtraction angiography

BACKGROUND AND PURPOSE: Contrast-enhanced MR angiography and extracranial color-coded duplex sonography are noninvasive, preoperative imaging modalities for evaluation of carotid artery stenosis. Innovative techniques and improvements in image quality require frequent reassessment of accuracy, reliability, and diagnostic value compared with those of digital subtraction angiography (DSA). We evaluated contrast-enhanced MR angiography and duplex sonography compared with DSA for detection of high-grade carotid artery stenoses. METHODS: Four readers, blinded to clinical symptoms and the outcome of other studies, independently evaluated stenoses on contrast-enhanced MR angiograms in 71 vessels of 39 symptomatic patients. Duplex sonography was also performed in all vessels. The severity of stenosis was defined according to North American Symptomatic Carotid Endarterectomy Trial criteria (0-29%, 30-69%, 70-99%, 100%). Results of both modalities were compared with the corresponding DSA findings. RESULTS: Contrast-enhanced MR angiography had a sensitivity and specificity of 94.9% and 79.1%, respectively, for the identification of carotid artery stenoses of 70% or greater. Sensitivity and specificity of duplex sonography were 92.9% and 81.9%, respectively. Combining data from both tests revealed a sensitivity and specificity of 100% and 81.4%, respectively, for concordant results (80% of vessels). CONCLUSION: Concordant results of contrast-enhanced MR angiography and duplex sonography increase the diagnostic sensitivity to 100%. The reliability of MR angiography is comparable to that of DSA. The combination of contrast-enhanced MR angiography and duplex sonography might be preferable over DSA for preoperative evaluation in most patients, thus reducing the risk of perioperative morbidity and improving the overall outcome.     

Non-invasive vascular imaging of peripheral vessels

The purpose of this review is to describe recent advances in non-invasive vascular imaging techniques and to discuss their current clinical applications for imaging of peripheral vessels. Principles for applying ultrasound, CT angiography (CTA), and magnetic resonance angiography (MRA) for non-invasive imaging of peripheral arteries and veins are presented. Clinical applications are reviewed for different vascular diseases, therapy planning, and follow-up studies. Conventional Doppler and color duplex sonography are the most cost-effective procedures to detect or rule out peripheral arterial occlusive disease (PAOD) and to provide specific recommendations for therapy. In the near future, contrast-enhanced MRA (CE MRA) with additional axial two-dimensional time-of-flight studies to search for non-anatomic runoff will replace diagnostic intra-arterial digital subtraction angiography (DSA) for planning of reconstructive surgery with acquisition slabs displaying projections similar to intra-arterial DSA. Color duplex sonography should also be the first non-invasive technique applied for the detection of peripheral aneurysms. Preoperative or preinterventional therapy planning of aneurysms may be performed by CTA or CE MRA. Compression ultrasound is the imaging procedure of choice in deep venous thrombosis (DVT). In the preoperative assessment of venous incompetence, color duplex sonography is the imaging technique which is sufficient in most cases. Received: 5 March 1998; Accepted: 16 March 1998     

MR imaging findings of intracranial dural arteriovenous fistulas: relations with venous drainage patterns

BACKGROUND AND PURPOSE: Venous drainage patterns are a major determinant of clinical outcome in intracranial dural arteriovenous fistula (DAVF) patients. In this study, we sought to identify MR imaging finding differences between DAVF types classified on the basis of venous drainage patterns. METHODS: Twenty-seven patients diagnosed as having DAVFs by conventional angiography were included. Medical records (n = 27), and MR imaging (n = 27) and MR angiography (MRA; n = 11) findings were retrospectively reviewed. MR imaging findings included flow void cluster, engorged ophthalmic vein/proptosis, white matter hyperintensity, intracranial hemorrhage, dilated leptomeningeal or medullary vessels, venous pouch, and leptomeningeal or medullary vascular enhancements. MRA findings included identifiable fistula, venous flow-related enhancement, and prominent extracranial vessels. Patients' presentations and MR imaging findings were compared among angiographic type I, II, and III cases (according to Borden's classification), and MRA findings were compared between cases with and without retrograde leptomeningeal venous drainage (RLVD). RESULTS: Patient presentations were aggressive in one (13%) of the type I cases, 5 (50%) of the type II cases, and 8 (100%) of the type III cases (P = .002). Aggressive presentations included hemorrhage, focal neurologic deficits, seizures, intracranial hypertension, and an altered mental status. MR images showed significantly higher frequencies of dilated leptomeningeal or medullary vessels in a higher type [0 in type I, 5 (42%) in type II, and 7 (100%) in type III], and of leptomeningeal or medullary vascular enhancements [0 in type I, 4 (33%) in type II, and 7 (100%) in type III]. By using MRA, fistulas were identified only in cases with RLVD (5 [83%]). Venous flow-related enhancement was present in 10 cases (91%). A sole false-negative case on MRA, as compared with conventional angiography, resulted from nonvisualization of the slow venous flow (8%). No false-positive fistula was found at the other intracranial sites in all cases. Overall, MRA assessment for DAVF was adequate for both fistula and venous flow-related enhancement in 10 cases (91%) and inadequate in a remaining case because of the fistular location out of field. CONCLUSION: MR imaging demonstration of leptomeningeal or medullary vascular dilation and enhancements may be associated with features that are considered predictors of a poor outcome and indicates a need for urgent therapy in intracranial dural AVF patients. MRA is a complementary tool for the identification of dural AVF with venous flow-related enhancement.     

3D-TOF MRA及SWI对脑血管畸形的对照研究

目的:通过分析脑动静脉畸形和海绵状血管瘤的的3D-TOF MRA及SWI磁共振表现,探讨3D-TOF MRA及SWI对脑血管畸形的诊断价值。方法:对我院收治的44例血管畸形进行高场磁共振成像,并加扫3D-TOF MRA及SWI序列,其中26例海绵状血管瘤、18例动静脉畸形。通过分析SW I和3D-TOF-MRA技术对脑血管畸形的显示情况,比较二者对脑血管畸形的检出率以及细微特征的鉴别能力等。结果:3D-TOF MRA可以清晰显示动静脉畸形的部位、大小、输入动脉的来源、输出静脉的去向等;海绵状血管瘤MRA检查均未见异常供血动脉,病灶内无异常流空信号。SWI可清晰显示海绵状血管瘤,病灶的数目及范围较常规序列增大;SWI只能显示动静脉畸形迂曲的小静脉,但不能直观显示畸形血管团的全貌及输入动脉等粗大血管的情况。结论:3D-TOF MRA技术对于AVM之类高流速低阻力的血管畸形的显示具有独特的价值,而SWI技术则对于海绵状血管瘤等小血管或低流速的血管畸形的显示具有明显的优势。     

Application of transcranial Doppler sonography in children with acute neurologic events due to primary cerebral and West Nile vasculitis

We describe the use of serial transcranial Doppler studies to evaluate neurovascular disease in three girls presenting with acute stroke due to primary cerebral vasculitis (n = 2) and West Nile vasculitis (n = 1). Correlation of abnormal findings on transcranial Doppler sonography was compared with those of MR angiography and conventional angiography in each child. All three girls had left middle cerebral artery infarcts on MR imaging, with an abnormal left middle cerebral artery detected by MR angiography, conventional angiography, and transcranial Doppler sonography in each child. In all three cases, findings of the transcranial Doppler sonography, MR imaging, and catheter angiography were concordant.     

Real-time interactive duplex MR measurements: application in neurovascular imaging

OBJECTIVE: Real-time interactive duplex MR imaging is a new phase-contrast MR imaging technique that enables the quantification and display of flow velocities in real time without the need for cardiac gating. We investigated the feasibility and reliability of the technique to assess hemodynamic information both in vitro and in vivo in the carotid arteries and in the venous sinuses. SUBJECTS AND METHODS: Real-time interactive duplex MR measurements (TR/TE, 53/27; flip angle, 90 degrees; encoding velocity, 100 or 150 cm/sec) were performed in vitro with a steady-flow phantom and in 10 healthy volunteers in whom common and internal carotid artery velocities were measured. In eight volunteers, velocity measurements were also performed in the superior sagittal sinus during both normal breathing and hyperventilation. Time-velocity plots were analyzed qualitatively and quantitatively and compared with findings from conventional segmented k-space phase-contrast MR imaging and Doppler sonography. RESULTS: Velocity determinations for real-time duplex MR and conventional phase-contrast MR imaging showed an in vitro correlation of 0.99 and an in vivo correlation of 0.83 (carotid arteries) and 0.76 (venous sinus). Velocity measurements in the carotid arteries with real-time MR imaging were significantly lower than those obtained with conventional phase-contrast MR (averaged, 7.8%; p = 0.003) or sonography (23.7%, p < 0.001), likely because of volume averaging. Small but significant velocity changes occurring in the venous sinus during hyperventilation were reliably identified with both MR techniques. CONCLUSION: Real-time interactive duplex MR imaging can be effectively applied in neurovascular imaging to obtain hemodynamic information.     

46例脑动静脉畸形的MRI和MRA分析

目的：探讨MRI和MRA检查在脑AVM临床诊断中的价值。方法：46例脑动静脉畸形作了常规MRI和MR血管造影,MRI采用SET1、T2加权成像,MRA采用三维时飞跃法。结果：MRI准确显示了46例AVM的瘤巢,11例可见亚急性出血灶,5例可见含铁血黄素沉积,23例病灶区组织软化或萎缩,4例有占位效应。3D-TOF RMA显示41例AVM供血动脉、23例引流静脉。5例加做增强3D-TOF及6例加做2D-TOF后,引流静脉显示明显改善。结论：MRI和MRA结合应用能对脑血管畸形作出较准确的诊断,为临床治疗提供所需的基本信息并对治疗效果作出客观的评价。     

MRA对脑动脉炎的诊断价值(附9例报告)

目的 评价磁共振血管成像（MRA）对脑动脉炎的诊断价值。方法 回顾性分析9例经临床证实为脑动脉炎患的MRA表现，并与MRI表现对照。结果 9例患的所有病灶均局限于一侧大脑半球或小脑半球，形态多呈圆形，斑片状。病灶在T1WI像呈低、等信号，在W2WI像呈稍高、高信号。MRI表现主要为梗塞灶、出血灶、脑炎和脑膜炎的炎症性病灶。MRA更加清晰显示近端脑动脉不规则狭窄或截断，远端脑动脉缺如，两侧血管分布不对称。结论 MRA是一种切实可行的血管成像技术，它不仅可提高脑动脉炎的诊断准确性，而且有助于评估其预后。     

MRI and color-coded duplex sonography: diagnosis of partial priapism

A case of partial priapism is reported diagnosed by contrast-enhanced MR imaging and color-coded duplex sonography. Follow-up examinations after 4 weeks and 3 months were performed. According to the results of color-coded duplex sonography and MRI, a partial priapism with development from the subacute stage to a fibrous residuum after spontaneous lysis was diagnosed. There are only very few cases of partial priapism reported in the literature and this is the first case report that demonstrates diagnosis and follow-up both by color-coded duplex sonography and contrast-enhanced MR imaging.     

Preoperative assessment of breast cancer: sonography versus MR imaging

OBJECTIVE: The purposes of our study were to compare the diagnostic value of whole-breast sonography and MR imaging as adjunctive techniques to mammography and to determine whether MR imaging should be used routinely in the preoperative assessment of patients with suspected breast cancer. SUBJECTS AND METHODS:. One hundred four women (age range, 34-84 years; mean age, 60 years) with findings highly suggestive of malignancy in the breast were examined with mammography, sonography, and dynamic MR imaging before undergoing surgery. All visualized suspicious lesions were correlated histologically. The diagnostic relevance of sonographic and MR imaging findings was compared with the diagnostic value of the findings of clinical examination and mammography alone. RESULTS:. Twenty-seven tumors showed multifocal or multicentric invasive growth at pathology. Of these 27, 48% were correctly diagnosed via mammography alone; 63%, via the combination of mammography and sonography; and 81%, via MR imaging. Nine of the index tumors were invisible on mammography but were detected on sonography. Use of sonography benefited 13 patients and produced two studies with false-positive findings. Use of MR imaging benefited seven patients and produced eight studies with false-positive findings. In summary, 93% of all patients gained no advantage from MR imaging. Relevant additional findings were significantly more frequent in patients with dense breasts. CONCLUSION: Although MR imaging is most sensitive for the detection of small tumors, routine preoperative MR imaging appears to be unnecessary for most patients if a combination of mammography and whole-breast sonography is used. Additional MR imaging can be restricted to problematic cases in women with dense breast parenchyma.     

MR imaging and angiography of primary CNS vasculitis of childhood

BACKGROUND AND PURPOSE: Primary angiitis of the central nervous system of childhood (cPACNS) is a rare and ill-defined disease. In the absence of a brain biopsy, the diagnosis is based on typical clinical and imaging abnormalities. The aim of this study was to analyze systematically the MR imaging and MR angiographic (MRA) abnormalities in a large cohort of children with cPACNS. METHODS: We analyzed the MR imaging features of a single pediatric center cohort of 45 cPACNS patients. MR imaging studies were performed for all patients, and both MR imaging and MRA were performed for 42 patients, who formed the cohort for review of the presence and correlation of lesions. Proportions were calculated by using the Fisher exact test, and agreement between MR imaging and MRA was calculated by using the McNemar test. The sensitivity of each diagnostic technique was established. RESULTS: The most-common pattern of parenchymal abnormality was multifocal, unilateral involvement, each in 42/45 patients (93%). The lateral lenticulostriate artery terrritory was affected in 56% of cases, with involvement of a supratentorial deep gray matter structure in 91%. No infratentorial lesion occurred in the absence of supratentorial abnormality. MRA was normal in 12/42 patients (28.6%). Among the abnormal studies, stenosis was detected on MRA in 83% and was "benign" in appearance in 73% of patients and "aggressive" in 16.7%. Involvement was proximal in 83% and distal in 27% of patients. Multiple ipsilateral lesions were seen in 63%. MR imaging was abnormal in every patient where MRA was abnormal. With the assumption of MR imaging as the gold standard, the sensitivity of MRA was 72%. The agreement between MR imaging and MRA for abnormality was significant (P = .04). CONCLUSION: We have illustrated the MR imaging and MRA appearances of cPACNS in the largest cohort to date. Both parenchymal and vascular lesions were predominantly proximal, unilateral, and multifocal within the anterior circulation. There was good agreement between MR imaging and MRA for lesion location. MR imaging findings were abnormal in all cases at diagnosis, and this remains the most sensitive technique to the detection of vasculitis.     

MR findings of spontaneous intracranial hypotension

Purpose:
To present the MR features of spontaneous intracranial hypotension (SIH) and to discuss the correlation of MR features with clinical manifestations. Material and Methods:
Between 1997 and 2000, 15 patients with SIH underwent brain MR investigation. Lumbar puncture for the measurement of cerebrospinal fluid (CSF) pressure was performed in 6 patients. Follow-up MR was obtained in 8 patients after the clinical symptoms had improved. We analyzed the MR findings of SIH, and discuss them in relation to CSF pressure and clinical manifestations. Results:
Fourteen of the 15 patients with SIH had abnormal MR findings. The imaging findings included: diffuse pachymeningeal enhancement in 13 patients; descent of the brain in 6 patients; and subdural effusion/hematoma in 2 patients. Low CSF pressure was shown at lumbar puncture in 5 out of 6 patients. Follow-up MR examination in the symptoms-relieved status demonstrated a recovery of the abnormal MR findings in 6 of 8 patients. Conclusion:
Our data revealed that MR is sensitive in diagnosing SIH. The presence of characteristic clinical manifestations and MR features are virtually diagnostic for SIH syndrome. Invasive lumbar puncture is thus reserved for the equivocal cases.     

小儿缺血性脑血管病的MRI及MRA诊断

目的 评价磁共振成像（MRI）及磁共振血管成像（MRA）对小儿缺血性脑血管病的诊断价值。方法 回顾性分析了42例小儿缺血性脑血管病患，年龄1.2-14岁，平均7.5岁，全部病例均以急性起病的运动，语言障碍为主要症状来诊，采用轴位T1，T2加权像，部分病例加做冠状位或矢状位成像，其中31例进行了时间飞跃（TOF）法MR血管成像。结果 本组共发现脑缺血8例，脑梗塞34例（其中腔隙梗塞22例，大面积梗塞12例），单支颅内动脉狭窄6例。多支动脉狭窄4例；单支动脉闭塞3例。多支动脉闭塞2例；MOYAMOYA病9例（其中3例可见脑底异常血管网）。4例图像上有运动伪影，但能达到诊断要求，全部病例中，MRI表现典型，能单独确诊36例，占85.7%，MRI与MRA相结合能确诊40例，达95.2%，其余2例仅用MRI及MRA不能明确诊断，需结合临床资料及经随访证实。结论 MRI结合MRA是小儿缺血性脑血管病的理想检查方法，可准确显示脑动脉的狭窄，闭塞性病变及其继发的脑缺血，梗塞病灶，对定性诊断具有重要价值。     

Prenatal diagnosis and postnatal follow-up of pericallosal lipoma: report of seven new cases

BACKGROUND AND PURPOSE: Pericallosal lipomas are rare tumors. Few reports have included their imaging characteristics. Furthermore, little is known about their evolutive course. Our purpose was to describe the imaging features of seven cases of pericallosal lipoma diagnosed in utero and followed up after birth. METHODS: We reviewed seven cases of pericallosal lipoma diagnosed by obstetric sonography (n = 7) and examined by fetal MR imaging (n = 5). Analysis of the complementary findings provided by fetal MR imaging was conducted. All findings were correlated with the postnatal imaging and clinical findings. RESULTS: Obstetric sonography easily showed the pericallosal lipoma in all seven patients. In one, however, it was misinterpreted as intracranial hemorrhage. The morphology and integrity of the underlying corpus callosum were less easy to assess by using sonography. Fetal MR imaging confirmed the fatty content and location of the lesion in all five cases. It showed the choroidal extension in two patients and the type of associated callosal anomaly in another patient better than did sonography. In two patients, the lipoma grew, as revealed by subsequent postnatal MR imaging. The results of the neurologic examinations remained normal for the five surviving patients at a mean follow-up of 3 years (1 month-9 years). CONCLUSION: Obstetric sonography is able to easily show pericallosal lipoma. Fetal MR imaging may be useful to characterize the lipomatous nature and the extension of the lipoma and the status of the corpus callosum. Long-term follow-up is necessary to understand the clinical consequences of such lesions.     

Ultrafast MR imaging of the fetus

OBJECTIVE: We examined the capability of ultrafast single-shot fast spin-echo imaging to assess different fetal organ systems compared with prenatal sonography, using autopsy or postpartum imaging as a standard of reference. SUBJECTS AND METHODS: Thirty women with complicated pregnancies (mean age of gestation, 190 +/- 54 days) underwent T2-weighted ultrafast MR imaging. MR images were analyzed with regard to diagnostic confidence in assessing abnormalities of fetal organ systems, and data were correlated with postpartum findings or necropsy. Results were compared with those of prenatal sonography. RESULTS: Using receiver operating characteristic curve analysis, diagnostic confidence of MR imaging was best for assessing the brain (area under the curve [Az] = 0.96) and spinal canal (Az = 1.0), uteroplacental unit (Az = 0.93), and lungs (Az = 0.91). Results for the heart (Az = 0.63) and extremities (Az = 0.77) were significantly lower than that of other organs (p < 0.001). Diagnostic accuracy increased with gestational age. No statistically significant difference between sonography and MR imaging was found for the detection of abnormality in any organ system. In three fetuses, MR imaging was superior to sonography in characterizing cerebral abnormalities. MR imaging was inferior to sonography in characterizing abnormalities of the heart and extremities. CONCLUSION: Our results indicate that ultrafast MR imaging can be used for in vivo fetal imaging, especially in assessing cerebral abnormalities. However, MR imaging should be restricted to situations in which sonographic findings are ambiguous or impaired.     

High-grade stenoses of the internal carotid artery: comparison of high-resolution contrast enhanced 3D MRA, duplex sonography and power Doppler imaging

PURPOSE: The objective of this study was to determine the agreement and diagnostic accuracy of high-resolution contrast enhanced magnetic resonance angiography (MRA) with integrated parallel acquisition techniques (iPAT), color coded duplex ultrasound (CCDS) and power Doppler ultrasound (PD) in the assessment of high-grade stenoses of the internal carotid artery (ICA). METHODS: Forty-four patients with 52 known or suspected stenoses of the internal carotid artery (ICA) were included in this prospective study. High-resolution MRA scans with a spatial resolution of 0.9 mm x 0.7 mm x 0.9 mm were acquired with an iPAT acceleration factor of 2 on a 1.5T MR system (Sonata Maestro Class, Siemens Medical Solutions, Erlangen, Germany) with a head, neck and body coil. For the 3D-CE MRA a fast spoiled gradient echo sequence (FLASH) was used. To compensate for the inherent signal loss with parallel imaging, a 1M contrast agent (gadobutrol, Gadovist, Schering, Berlin, Germany) was used. Stenoses were quantified by two readers in consensus in cross-sectional area measurements and graded according to the NASCET criteria. Using color coded duplex ultrasound (CCDS) and power Doppler (PD; Logiq 9, GE), the stenoses were also graded by two readers in consensus according to the NASCET criteria from intra- and post-stenotic diameter measurements. The results of MRA, CCDS and PD were compared to intraoperative findings or to follow-up examinations. RESULTS: High-resolution MRA allowed an excellent grading of vascular stenoses. In 70-90% degrees of stenosis there was an underestimation of the degree of stenosis in MRA as well as in CCDS. However, there was an overestimation of 90% stenoses in both MRA and CCDS. Pseudoocclusions with a lumen of less than one millimeter were occasionally rated as a complete occlusion in MRA. CONCLUSION: A combination of MRA and duplex sonography seems reasonable for the accurate grading of stenoses and determination of distal stenoses downstream. However, the accuracy of duplex ultrasound depends on the examiner's experience.     

Measurements before endovascular repair of abdominal aortic aneurysms. MR imaging with MRA vs. angiography and CT

Purpose:
1) To compare measurements obtained with MR imaging (MRI)/contrast-enhanced MR angiography (CE MRA) with measurements obtained with angiography (DSA) and CT, for stent-graft sizing of abdominal aortic aneurysms (AAA). 2) To compare MRA measurements obtained with the two post processing techniques MIP (maximum intensity projection) and VRT (3D volume rendering technique). Material and Methods:
The prospective study included 20 consecutive patients with AAA identified by DSA and CT as suitable for endovascular repair. For the study, MRI/CE MRA was performed. Five measurement variables for stent-graft sizing were chosen. Comparisons were made between MRI/CE MRA, DSA and CT, and between observers. Comparisons were also made between MIP and VRT. Results:
Significantly shorter lengths were obtained with MRA-MIP than with DSA. Three out of six diameter measurements were significantly smaller on MRI/CE MRA than on DSA and CT. No significant differences were found between the observers. One diameter measurement was significantly smaller on MIP than on VRT, while the other measurements showed no significant differences. Conclusion:
The length measurements obtained with MRA-MIP were probably more correct than those with DSA. For more reliable diameter measurements with CE MRA, improvements of the technique, including VRT reconstructions and a standardized determination of the vessel boundaries, are needed.     

Mid-term follow-up after percutaneous hydrodynamic thrombectomy in lower limb ischemia: initial experience with two-dimensional MR imaging and three-dimensional MR angiography

PURPOSE: To assess noninvasively mid-term patency, reocclusion, and mid-term changes of the arterial wall after percutaneous hydrodynamic thrombectomy in patients with acute lower limb ischemia using magnetic resonance (MR) imaging/MR angiography (MRA). MATERIALS AND METHODS: Arterial wall and luminal changes were evaluated in 16 patients (10 men, six women; mean age, 70 years), with a minimum follow-up of 12 months after percutaneous thrombectomy with a hydrodynamic catheter for acute lower limb ischemia (embolic, n = 5; thrombotic, n = 11). Adjunctive PTA was performed in 44%. The mean follow-up was 23 months +/- 7.6 (range, 12-33 months). MR imaging and MRA were performed on a 1.0 T system using an extremity coil and two-dimensional (2D) time-of-flight, turbo spin echo, 2D gradient echo, and contrast enhanced three-dimensional (3D) gradient echo sequences. RESULTS: In one patient, a complete reocclusion was noted and, in two patients, a hemodynamically insignificant restenosis (< or = 50%) was identified with MR imaging. This was in accordance with color flow duplex sonography, physical examination, ankle/brachial index measurements, and the treadmill test. The MR morphometry documented an increase of the entire vessel area from 48.9 mm2 +/- 3.3 (control segments) to 55.5 mm2 +/- 2.8 at the treated segments (+13.3%; P < .05). The vessel wall area increased from 31.7 mm2 +/- 1.8 to 39.4 mm2 +/- 2.3 (+24.4%; P < .05). The mean area stenosis grade was 12%. CONCLUSION: MR imaging with use of morphometric analysis is a possible tool to noninvasively determine the mid-term patency and restenosis/reocclusion and remodeling process after percutaneous thrombectomy and other interventional procedures.     

MR imaging and MR angiography in preoperative evaluation of intracranial meningiomas

A group of 41 patients with intracranial meningiomas were examined by MR imaging (MRI) and MR angiography (MRA) to assess the. clinical value of MRA in the preoperative evaluation of these patients. The results of MRA were compared with the results of intraarterial cerebral catheter X-ray angiography (XRA; n = 19) and with the operative findings (n = 41 ): Our results showed a good correlation between MRA and XRA/surgery in demonstrating the relationship between the tumor and adjacent venous and arterial structures. Use of MRA was also helpful in demonstrating the degree of intrinsic tumor vascularity. It also supplied important information for operative planning Adjunct XRA was mandatory if detailed information about tumor-feeding vessels was requested by the neurosurgeon, especially in highly vascularized angiomatous meningiomas and in meningiomas suspected of tumor feeding by vessels of the internal carotid artery. Correspondence to: A. Goldmann     

Fast MR imaging of fetal CNS anomalies in utero

BACKGROUND AND PURPOSE: Although sonography is the primary imaging technique for evaluating the developing fetus, significant limitations exist in the sonographic prenatal diagnosis of many brain disorders. Fast MR imaging is increasingly being used to determine the underlying cause of nonspecific fetal CNS abnormalities detected sonographically and to confirm or provide further support for such anomalies. Our goal was to determine the value of MR imaging in establishing the diagnosis of fetal CNS anomalies, to ascertain how this information might be used for patient counseling, and to assess its impact on pregnancy management. METHODS: We prospectively performed MR examinations of 73 fetuses (66 pregnancies) with suspected CNS abnormalities and compared these with available fetal sonograms, postnatal images, and clinical examinations. Retrospectively, the impact on patient counseling and pregnancy management was analyzed. RESULTS: Images of diagnostic quality were routinely obtained with in utero MR imaging, which was particularly valuable in detecting heterotopia, callosal anomalies, and posterior fossa malformations, and for providing excellent anatomic information. We believe that 24 (46%) of 52 clinical cases were managed differently from the way they would have been on the basis of sonographic findings alone. In every case, the referring physicians thought that MR imaging provided a measure of confidence that was not previously available and that was valuable for counseling patients and for making more informed decisions. CONCLUSION: Sonography is the leading technique for fetal assessment and provides reliable, inexpensive diagnostic images. Fast MR imaging is an important adjunctive tool for prenatal imaging in those instances in which a complex anomaly is suspected by sonography, when fetal surgery is contemplated, or when a definitive diagnosis cannot be determined.