Usefulness Of MR Angiography Research Articles

Usefulness of Silent MRA for Evaluation of Aneurysm after Stent-Assisted Coil Embolization.

ObjectiveTo determine the usefulness of Silent MR angiography (MRA) for evaluating intracranial aneurysms treated with stent-assisted coil embolization.Materials and MethodsNinety-nine patients (101 aneurysms) treated with stent-assisted coil embolization (Neuroform atlas, 71 cases; Enterprise, 17; LVIS Jr, 9; and Solitaire AB, 4 cases) underwent time-of-flight (TOF) MRA and Silent MRA in the same session using a 3T MRI system within 24 hours of embolization. Two radiologists independently interpreted both MRA images retrospectively and rated the image quality using a 5-point Likert scale. The image quality and diagnostic accuracy of the two modalities in the detection of aneurysm occlusion were further compared based on the stent design and the site of aneurysm.ResultsThe average image quality scores of the Silent MRA and TOF MRA were 4.38 ± 0.83 and 2.78 ± 1.04, respectively (p < 0.001), with an almost perfect interobserver agreement. Silent MRA had a significantly higher image quality score than TOF MRA at the distal internal carotid artery (n = 57, 4.25 ± 0.91 vs. 3.05 ± 1.16, p < 0.001), middle cerebral artery (n = 21, 4.57 ± 0.75 vs. 2.19 ± 0.68, p < 0.001), anterior cerebral artery (n = 13, 4.54 ± 0.66 vs. 2.46 ± 0.66, p < 0.001), and posterior circulation artery (n = 10, 4.50 ± 0.71 vs. 2.90 ± 0.74, p = 0.013). Silent MRA had superior image quality score to TOF MRA in the stented arteries when using Neuroform atlas (4.66 ± 0.53 vs. 3.21 ± 0.84, p < 0.001), Enterprise (3.29 ± 1.59 vs. 1.59 ± 0.51, p = 0.003), LVIS Jr (4.33 ± 1.89 vs. 1.89 ± 0.78, p = 0.033), and Solitaire AB stents (4.00 ± 2.25 vs. 2.25 ± 0.96, p = 0.356). The interpretation of the status of aneurysm occlusion exhibited significantly higher sensitivity with Silent MRA than with TOF MRA when using the Neuroform Atlas stent (96.4% vs. 14.3%, respectively, p < 0.001) and LVIS Jr stent (100% vs. 20%, respectively, p = 0.046).ConclusionSilent MRA can be useful to evaluate aneurysms treated with stent-assisted coil embolization, regardless of the aneurysm location and type of stent used.

Usefulness of MRA‐DWI mismatch in neuroendovascular therapy for acute cerebral infarction

This study evaluated the usefulness of MR angiography (MRA)-diffusion-weighted imaging (DWI) mismatch in neuroendovascular therapy over 3 h after onset of acute cerebral infarction. The subjects were 14 cases (age, 73 ± 8.4 years) who had an anterior circulation deficit on DWI/MRA on arrival and underwent neuroendovascular therapy over 3 h after onset. MRA-DWI mismatch (MDM) (+) was defined as 'major artery lesion (+) and diffusion-weighted image-Alberta Stroke Program Early CT Score (DWI-ASPECTS) ≥6'; MDM (-) was defined as 'major artery lesion (+) and DWI-ASPECTS <6'. Reperfusion was achieved in nine of 14 patients (64%) undergoing neuroendovascular therapy. Within the reperfusion group, in the five MDM (+) patients and the four MDM (-) patients, the outcome was a favorable clinical response in the MDM (+) group. The modified Rankin Scale (mRS) scores after 90 days were 0-2 in 3 (60%) and 3-6 in 2 (40%) of the MDM (+) group patients and 0-2 in 0 (0%) and 3-6 in 4 (100%) of the MDM (-) group patients. In the MDM (+) group, a good outcome was achieved. However, the number of cases was small, so this was not a significant difference. Within the non-reperfusion group, in the three MDM (+) patients and the two MDM (-) patients, the mRS scores after 90 days were 0-2 in 1 (33%) and 3-6 in 2 (67%) of the MDM (+) group patients and 0-2 in 0 (0%) and 3-6 in 2 (100%) of the MDM (-) group patients. In both groups, the outcome was poor. With neuroendovascular therapy, a good outcome with reperfusion was achieved in the MDM (+) group compared to the MDM (-) group. This suggests that the presence or absence of MDM may be useful in determining prognosis after reperfusion.

Preoperative evaluation of pulmonary artery morphology and pulmonary circulation in neonates with pulmonary atresia--usefulness of MR angiography in clinical routine.

BackgroundTo explore the role of contrast-enhanced magnetic resonance angiography (CE-MRA) in clinical routine for evaluating neonates with pulmonary atresia (PA) and to describe their pulmonary artery morphology and blood supply.CE-MRA studies of 15 neonates with PA (12 female; median weight: 2900 g) were retrospectively evaluated by two radiologists in consensus. Each study was judged to be either diagnostic or non-diagnostic depending on the potential to evaluate pulmonary artery morphology and pulmonary blood supply. In those cases where surgery or conventional angiocardiography was performed results were compared.ResultsCE-MRA was considered diagnostic in 87%. Pulmonary artery morphology was classified as "confluent with (n = 1) and without (n = 1) main pulmonary artery", "non-confluent" (n = 6) or "absent" (n = 7). Source of pulmonary blood supply was "a persistent arterial duct" (n = 12), "a direct" (n = 22) or "indirect (n = 9) aortopulmonary collateral artery (APCA)" or "an APCA from the ascending aorta" (n = 2). In no patient were there any additional findings at surgery or conventional angiocardiography which would have changed the therapeutic or surgical approach.ConclusionsCE-MRA is a useful diagnostic tool for the preoperative evaluation of the morphology of pulmonary arteries and blood supply in neonates with PA. In most cases diagnostic cardiac catheterization can be avoided.

Hibernoma: a case report demonstrating usefulness of MR angiography in characterizing the tumor

Hibernoma is a rare, benign soft-tissue tumor composed of brown fat. In the past, there has been an extensive discussion of the CT attenuation and MRI signal characteristics of hibernomas. However, recent reports have focused upon the tumor vascularity of hibernomas. We describe the only case in the literature which utilizes state of the art contrast enhanced MR angiography to clearly characterize the surface and intratumoral vessels to help confirm the diagnosis of a hibernoma and aid in the preoperative planning.

Idiopathic infantile arterial calcification: imaging evaluation and the usefulness of MR angiography

Idiopathic infantile arterial calcification (IIAC) is a rare condition characterized by extensive calcification and stenosis of large and medium-size arteries. The etiology of the disease is unknown. However, the inheritance pattern has been shown to be autosomal recessive. The clinical presentation is variable, including cardiac failure (most common clinical finding), hypertension, and respiratory failure. Plain radiography, sonography and MRI can aid in the diagnosis. We present a case in which contrast-enhanced MR angiography with breath-hold and cardiac gating techniques allowed complete evaluation of the extent of this disease.

Usefulness of MR angiography in cases of central vertigo

Objective: Syndromal vertigo is defined as a combination of vestibular function disturbance and cranial nerve or cerebral function disturbance. The purpose of this study was to provide simplified MRA criteria for identifying morbidity and to analyze the relationship between imaging findings and clinical manifestations. Methods: Thirty-three individuals with symptoms of syndromal vertigo and vertebrobasilar territory disease were examined by equilibriometry, MR imaging (MRI), and MRA. Results: Twenty-five VA or BA abnormalities (75.8%) were found, and eight combined VA and BA abnormalities (24.2%) were found. Conclusion: MRA is advantageous over conventional angiography for a less invasive method. MRA can reveal abnormalities even in cases of “solo-vertigo” with no observed neurologic abnormalities. In our series, abnormalities were confirmed by MRA even in cases with no concomitant such as hypertension, coronary heart disease, or diabetes mellitus, which are regarded as latent risk factors for stroke.

Usefulness of MR angiography in cases of central vertigo

Objective: Syndromal vertigo is defined as a combination of vestibular function disturbance and cranial nerve or cerebral function disturbance. There is evidence that MR angiography (MRA), providing angiogram-like images of the intracranial and extracranial arterial flow, could replace invasive methods for diagnosing central vertigo. The purpose of this study was to provide simplified MRA criteria for identifying morbidity and to analyze the relation between imaging findings and clinical manifestations. Methods: Thirty-three individuals with symptoms of syndromal vertigo and vertebrobasilar territory disease were examined by equilibriometry, MR imaging (MRI) and MRA. Results: Under MRA, vertebral artery (VA) stenosis was more common than VA occlusion (23 vs. nine cases, respectively). A basilar artery (BA) deviation was found in eight cases (24.2%). Twenty-five VA or BA abnormalities (75.8%) were found, and eight combined VA and BA abnormalities (24.2%) were found. Conclusion: We emphasize three points as follows. MRA is advantageous over conventional angiography for less invasive method. MRA can reveal abnormalities even in cases of ‘solo-vertigo’ with no observed neurologic abnormalities. In our series, abnormalities were confirmed by MRA even in cases with no concomitant such as hypertension, coronary heart disease, or diabetes mellitus, which are regarded as latent risk factors for stroke.

MR angiography of moyamoya disease before and after encephaloduroarteriosynangiosis.

Our purpose was to evaluate the usefulness of MR angiography in revealing moyamoya disease before and after encephaloduroarteriosynangiosis. Twenty-six patients (51 hemispheres) with angiographically confirmed moyamoya disease who underwent encephaloduroarteriosynangiosis were included in the study. Findings on preoperative MR angiography were compared with those on conventional angiography. Postoperative neurologic status was categorized as poor, fair, good, or excellent. Postoperative MR angiography was examined for the appearance of the superficial temporal artery, changes in moyamoya vessels, and transdural collateral vessels into the middle cerebral artery territory. Preoperative MR angiography revealed moyamoya disease in all patients (diagnostic accuracy, 100%). MR angiography correctly depicted the degree of internal carotid artery stenosis in 37 arteries (73%), moyamoya vessels in 33 hemispheres (65%), and the degree of stenosis in the middle, anterior, and posterior cerebral arteries in 125 (82%) of 153 arteries. After surgery, 39 hemispheres showed an excellent outcome, eight showed a good outcome, two a fair outcome, and two a poor outcome. On postoperative MR angiography, vascular supply to the middle cerebral artery territory via transdural collateral vessels increased in 28 hemispheres (55%) and decreased in four (8%). The size of the superficial temporal artery increased in 41 (80%) of 51 hemispheres. The extent of moyamoya vessels decreased in 27 hemispheres (53%) after surgery. MR angiography can show the changes in the superficial temporal artery and development of transdural collateral vessels after encephaloduroarteriosynangiosis. Because MR angiography is noninvasive, it is valuable for evaluating postoperative changes.

Usefulness of MR angiography in detection of persistent trigeminal arteries.

To examine the usefulness of magnetic resonance angiography (MRA) in detection of persistent trigeminal arteries (PTA). 3D-time-of-flight (TOF)-MRA images obtained from 1100 patients (798 males and 302 females aged 6-75 years with a mean of 55 years) at our and related institutions were examined retrospectively for PTA. The course of the PTA was classified into the posteromedial type and posterolateral type. Charts of the patients were also examined retrospectively for clinical symptoms related to PTA. PTA was observed in 5 (0.45%) of the 1100 patients, and no aneurysm or arteriovenous malformation was noted in any of these 5 patients. PTA was the posteromedial type in 2 and posterolateral type in 3. PTA was possibly related with clinical symptoms in only 1 patient with oculomotor paresis. MRA is useful for non-invasive screening for PTA.

Angio-RM dei tronchi sovraortici

Several studies have been published on the usefulness of MR angiography of carotid bifurcations and epiaortic vessels. Almost all of them were carried out with the Time-of-Flight technique, most of them using the 2D acquisition modality. These studies claim a good overall sensitivity and specificity by comparison to digital subtraction angiography, Doppler ultrasound or both in the demonstration of carotid clinically relevant stenosis, with a slight overestimation of the degree of stenosis, especially in the moderate and severe groups. Unlike Doppler ultrasound, distal cervical and proximal intracranial arteries can be relatively well evaluated by MR angiography. Nevertheless, MR angiography also has limitations, among the best known, difficult visualization of the origin of neck arteries, inaccurate depiction of vessel morphology in case of complex flow and unreliable quantification of the degree of stenosis have to be mentioned. To get the most of the diagnostic potential of MR angiography, imaging strategies and technical considerations have to be adapted to the morphological and hemodynamic particularities of the different segments of the supraaortic arterial structures.

Contrast-enhanced MR angiography.

Despite many optimizations, the current limitations of plain MR angiography include: saturation that impairs the visualization of veins and arteries with slow flow and spin-dephasing signal voids in locations with turbulent flow. Recently, the use of contrast agents has been proposed to cope with these remaining problems. Because of induced shortening of the T1 of the blood, saturation in the blood vessels is overcome. As a result, arteries and veins are visualized with the same signal intensity, which makes the technique less flow-dependent. In combination with short T1-weighted acquisitions, today CE MRA can be obtained while the patient is holding his breath. This last approach is most promising for abdominal applications since the respiratory motion can be frozen. As these acquisitions also use very short echo times, spin dephasing can be reduced. In conclusion, the use of contrast agents has greatly increased the clinical usefulness of MR angiography.

Usefulness of MR Angiography in Patients with Non-Traumatic Intracranial Hemorrhagic DiseasesI

Usefulness of MR Angiography in Patients with Non-Traumatic Intracranial Hemorrhagic DiseasesI

Selective MR angiography and intracranial collateral blood flow.

This study evaluates the usefulness of MR angiography (MRA) in analyzing the individual collateral flow dynamics and anatomy of the circle of Willis in patients with high-grade extracranial carotid stenosis or occlusion. Selective MRA of the carotid or vertebrobasilar territory was performed by means of presaturation of up to three of the brain-supplying arteries at the level of the middle or lower neck (angled presaturation slabs). Results obtained with selective and nonselective arterial MRA in 45 consecutive patients were compared with findings at transcranial Doppler ultrasonography and intraarterial angiography, the latter serving as the "gold standard." Sensitivity of selective MRA in detecting intracranial collateral circulation via the anterior and posterior communicating artery was 95 and 97%, respectively; sensitivity in depicting extracranial to intracranial transorbital flow was lower (67%). Nonselective arterial MRA was 100% sensitive in detecting a nonfilling of the horizontal (A1) segment of the anterior cerebral artery and in identifying an origin of the posterior cerebral artery from the intracranial carotid artery. Visibility of the posterior communicating artery at MRA predicted for pathological collateral flow via this vessel in all cases. We conclude that selective and nonselective MRA of the cerebral arteries as used here is the most powerful noninvasive method to demonstrate collateral circulation via the basal communicating arteries and to identify hemodynamically relevant anatomic variants of the circle of Willis.

Posttraumatic carotid artery dissection in children: evaluation with MR angiography.

Dissection of the cervical portion of the carotid artery is a rare event in children that usually occurs after blunt injury to the neck. Symptoms and signs of stroke may develop days to years after injury, leading to delays in therapy [i , 2]. Early reports have shown the usefulness of MR angiography in the evaluation of carotid artery disease in adults [3, 4]. As this technique is noninvasive and can be performed in conjunction with routine MR imaging, it is potentially useful in examining children suspected of having carotid artery dissection. We describe two cases that demonstrate the use of MR angiogmaphy in the examination of children with carotid artery dissection.

The Usefulness of MRAngiography in Head and Neck Surgery

The Usefulness of MRAngiography in Head and Neck Surgery