Performance Of Magnetic Resonance Angiography Research Articles

Takayasu arteritis: Prevalence and clinical presentation in Switzerland.

ObjectiveTakayasu arteritis (TAK) is a rare immune-mediated vasculitis of the aorta and its branches. Aims were to calculate prevalence and incidence in Switzerland, to assess disease activity and performance of MR-Angiography (MRA).Methods31 patients were recorded in a database, 27 were followed prospectively up to 3 years. Prevalence was calculated based on data of the national statistical bureau. Disease activity was defined using the revised EULAR criteria. MRA depicted stenotic changes and aortic wall enhancement.ResultsA disease prevalence of 14.5/1.000.000 inhabitants and an incidence of 0.3/1.000.000 per year was calculated. Aortic wall enhancement was found in 10 patients while in clinical and serological remission. EULAR criteria missed 5 patients with disease activity with isolated elevations of ESR/CRP. Arterial stenosis did not change over time in 5 cases, it improved in 2 and increased in 7. At follow-up 16 patients were treated with tocilizumab, 11/16 in monotherapy, 5 patients were treatment-free, 25/27 stayed in remission.ConclusionIn addition to prevalence and incidence, our data show that MRA qualifies to detect subclinical disease activity, but, on the other hand, that EULAR criteria may miss disease activity in case of isolated elevation of ESR/CRP.

Comparative Performance of Magnetic Resonance Angiography and Digital Subtraction Angiography in Vessel Involvement of Pediatric Moyamoya Disease

Background: Recently, magnetic resonance angiography (MRA) has been widely used for the detection of moyamoya disease (MMD). However, the diagnostic performance of MRA in the detection of the affected artery in MMD remains unclear. Objectives: To assess the diagnostic performance of MRA in detecting internal carotid artery (ICA), anterior cerebral artery (ACA), middle cerebral artery (MCA) or posterior cerebral artery (PCA) involvement (including stenosis and occlusion) compared with digital subtraction angiography (DSA) in pediatric MMD. Patients and Methods: Fifty-eight pediatric patients diagnosed with MMD by MRA and DSA within one week from September 2010 to September 2011 were evaluated. Results: Among 261 vessels of occlusion demonstrated by MRA, 48 vessels of stenosis were confirmed by DSA. There was a similar detection rate of vascular lesions by MRA and DSA in ICA, ACA and PCA. More lesions in MCA were detected as occlusion by MRA than DSA. MRA was more sensitive and accurate in diagnosing vascular lesions, including ICA, ACA and MCA, while it was most specific and lowest sensitive was found in diagnosing PCA. In addition, MRA was moderate to highly consistent with DSA in diagnosing MCA and PCA. Conclusion: MRA had an important diagnostic value in the detection of the affected ICA, ACA, MCA and PCA with DSA as the gold standard, but with an overestimated evaluation of stenosis severity in pediatric MMD.

Methods and time schedule for follow-up of intracranial aneurysms treated with endovascular embolization: a systematic review

Background and purposeTo review the diagnostic value of angiographic methods and the optimal timetable for follow-up imaging of patients after endovascular treatment of intracranial aneurysms. Material and methodsA comprehensive computer-aided search for relevant primary papers was performed using the MEDLINE, PubMed, Embase, and Cochrane Collaboration database from January 1991 to March 2011. Original papers were included that reported either diagnostic value of angiographic modalities for follow-up vs. digital subtracted angiography (DSA) or comparison of aneurysm occlusion rate in delayed vs. early follow-up. ResultsThe systematic review identified 35 relevant studies: 3 on the diagnostic value of three-dimensional (3D) DSA, 30 on the performance of magnetic resonance angiography (MRA), and 3 on time schedules for follow-up. 3D DSA had sensitivity of 100%, and specificity of 58.3-94.7%. Magnetic resonance angiography had sensitivity of 28.4-100%, and specificity of 50.0-100%. The proportion of aneurysms that recanalized between the early follow-up examination at 6 months and the delayed imaging at 1.5-6.0 years was 0-2.5%. ConclusionsMagnetic resonance angiography seems to be the best imaging method for the follow-up. In selected cases, when invasive angiography is necessary, 3D DSA should be considered to improve the diagnostic accuracy. Most patients who present with stable and adequate aneurysm occlusion at 6 months after coiling may not require further follow-up.

Unilateral Venous Thalamic Infarction in a Child Mimicking a Thalamic Tumor

Unilateral thalamic infarction is a rare condition in adults. This is a case report of a young child presenting with left-sided hemiparesis of sudden onset due to an unilateral venous thalamic infarction. This was attributed to an asymmetric thrombosis of the cerebral internal veins, a partial thrombosis of the vein of Galen and straight sinus. Magnetic resonance imaging resulted primarily in the differential diagnosis of a cerebral tumor or an intracerebral abscess, leading to stereotactic puncture. Subsequent magnetic resonance venography facilitated the correct diagnosis. Heparin-induced thrombocytopenia necessitated anticoagulation treatment with hirudin and later, warfarin. The patient made a complete recovery. We conclude that unclear unilateral thalamic lesions might be symptomatic of a cerebral deep venous thrombosis and might mimic a thalamic tumor. In uncertain cases, we suggest rapid performance of magnetic resonance angiography.

MR angiography in the follow-up of intracranial aneurysms treated with Guglielmi detachable coils: systematic review and meta-analysis

The aim of this study was to systematically review published data on the diagnostic performance of magnetic resonance angiography (MRA) compared with digital subtraction angiography as reference standard in the follow-up of intracranial aneurysms treated with Guglielmi detachable coils. A systematic search for relevant studies was performed of the PubMed/MEDLINE and Embase databases. Two reviewers independently assessed the methodological quality of each study. A meta-analysis of the reported sensitivity and specificity of each study was performed. The inclusion criteria were met by 16 studies. The studies had moderate methodological quality. Pooled sensitivity and specificity of non-enhanced time-of-flight MRA (TOF-MRA) for the detection of residual flow (within the aneurysmal neck and/or coil mesh) were 83.3% (95% CI 70.3-91.3%) and 90.6% (95% CI 80.4-95.8%), respectively. Pooled sensitivity and specificity of contrast-enhanced MRA (CE-MRA) for the detection of residual flow were 86.8% (95% CI 71.4-94.5%) and 91.9% (95% CI 79.8-97.0%), respectively. All pooled estimates were subject to heterogeneity. There were no statistically significant differences in pooled sensitivity and specificity between TOF-MRA and CE-MRA. The results of this study suggest that both TOF-MRA and CE-MRA achieve a moderate to high diagnostic performance. However, the findings should be interpreted with caution because the included studies were of moderate methodological quality and all pooled estimates were subject to heterogeneity. More well-designed studies are required to confirm the current results and MRA at higher field strength (>1.5 T) needs to be further explored.

Performance of magnetic resonance angiography in suspected acute pulmonary embolism

Pulmonary embolism (PE) is a common and potentially fatal disorder. Non-specific findings make the clinical diagnosis of PE difficult. To assess the diagnostic value and inter-observer agreement of magnetic resonance angiography (MRA) in a cohort of patients with suspected PE, we conducted a prospective clinical study. MRA was compared for sensitivity and specificity to a diagnostic strategy including clinical probability, D-dimer testing, spiral CT, ultrasound leg compression and pulmonary angiography. A total of 89 patients with clinically suspected PE were included: the clinical probability of PE was intermediate or high in 78, and low in the remaining 11. All patients underwent monoor multi-slice spiral CT and MRA with gadolinium injection (both within 24 hours of entry to the study). Anticoagulation was withheld in patients concerned about the strategy. All subjects were followed up for 3 months. MRA was read independently by two experienced teams of radiologists: one local and one from another university centre. Spiral CT was positive in 62 of 63 cases of confirmed PE. No patient with negative CT findings was positive ultrasonographically. Only one patient with a negative CT (and negative ultrasound) had a recurrent thromboembolic event. The first team diagnosed PE with MRA in 47 cases, with a sensitivity of 71% and a specificity of 92%; the second team obtained the diagnosis in 23 cases, with a sensitivity of 31% and a specificity of 85%. Inter-observer agreement between MRA reading was low: Kappa = 0.16 (-0.01 to 0.33); p = 0.07. In conclusion, compared with a non-invasive strategy based on spiral CT, the diagnostic value of MRA is limited by poor inter-observer agreement.

MR contrast media for cardiovascular imaging

MR contrast media improve the diagnostic capability of MRI and MRA. They are used in the discrimination of viable and non-viable myocardium, transmural and non-transmural infarction, occlusive and reperfused infarction and for measurement of myocardial perfusion. Currently, clinical studies are almost completely restricted to the use of extracellular non-specific MR contrast media (i. e., Gd-DTPA, Gd-DTPA,-BMA, Gd-BOPTA, Gd-D03A). However, the feasibility of using intravascular, necrosis specific or intracellular MR contrast media or endogeneous substrates as specific MR contrast media in cardiovascular imaging has been demonstrated in experimental and a few clinical studies. Intravascular contrast media (i. e., MS-325 or NC100150 Injection) allow assessment of microvascular integrity and performance of MR angiography. Necrosis specific contrast media (i. e., Gadophrin-2) have been used for sizing the extent of infarcted myocardium while intracellular contrast media (i. e., Mn-DPDP) delineate viable myocardium. Endogenous contrast media (i. e., Deoxyhemoglobin, Na (+) or K (+)) have been tested for detecting the alterations in concentrations of these ions in infarcted myocardium and for perfusion measurements. Furthermore, intravascular MR contrast media may be useful for MRA and MRI guided cardiovascular interventions.

Use of magnetic resonance angiography to select candidates with recently symptomatic carotid stenosis for surgery: systematic review

Objective: To determine if sufficient evidence exists to support the use of magnetic resonance angiography as a means of selecting patients with recently symptomatic high grade carotid stenosis for surgery.Design:...