Magnetic Resonance Angiography In Evaluation Research Articles

Quality assurance for magnetic resonance angiography of the chest in patients suspected of pulmonary embolism during iodinated contrast shortage in the emergency department setting.

COVID-19 lockdowns resulted in a global shortage of iodinated contrast media. Therefore, alternative imaging protocols were devised to evaluate patients arriving to the emergency department (ED) with suspicion of pulmonary embolism (PE). This quality assurance (QA) aims to compare diagnostic potential between alternative magnetic resonance angiography (MRA) protocol over the gold standard computed tomography angiography (CTA) by evaluating MRA imaging quality, scanner type/imaging sequence, and any risk of misdiagnosis in patients with symptoms of PE. This retrospective study compromised of 55 patients who arrived to ED and underwent MRA of the chest for suspicion of PE during the months of May to June 2022. Data regarding their chief complaints, imaging sequence, and MRA results were collected. Two fellowship-trained faculty radiologists reviewed the MRA scans of the patients and scored the quality using a Likert scale. Two patients were positive for PE and 53 patients showed negative results. Regarding the scan quality issues, motion was noted in 80% of the 55 studies that we reviewed. Significant associations (P < 0.009) between Likert scale scores and initial complaint category were found. The characteristic symptoms associated with suspicion of PE, namely, shortness of breath, chest pain, and cough were distributed among the 1 and 2 categories, reflecting the most optimal vessel opacification scores. We found no risk of misdiagnosis after reviewing the electronic medical record for follow-up appointments within 6 months of ED visit. Patients were screened for PE with MRA as an alternative imaging tool during times of contrast shortage. Further, evaluation of MRA with CTA, side by side, in a larger patient population is required to increase the validity of our QA study.

Evaluation of Patients with Vertigo by Cranial Magnetic Resonance Imaging (MRI)

Background: Vertigo is a symptom that neurologists and otologists are confronted with. Magnetic resonance image (MRI) is used for imaging. Objective: To determine the diagnostic yield of MRI in patients with vertigo and to Identify the most common causes. Patients and Methods: This observational study involved 110 vertigo complaining patients attending the MRI unit of Rizgary teaching hospital examined by 0.2 Tesla MRI between June 2007 and September 2008.Collected variables divided into Group 1 (normal MRI) and Group 2 (abnormal MRI) analysed and compared. Results: Group 1= (70%) and Group 2=(30%), abnormal MRI findings in male patients was (59.6%), in female (40.4%,) the commonest abnormalities were cerebellopontine angle (CPA) space occupying lesions (SOL) (9.2%), cerebellar SOL (7.4%), 4th ventricle SOL (7.4%) and deep white matter ischemia (7.4%), most of patients with vascular problems were more than 50 years. In (35.4%) of patients, vertigo was less than one month duration, (50%) of which had abnormal MRI findings. Out of seven patients with normal MRI, 5 patients showed vascular lesion on magnetic resonance angiography (MRA). Conclusion: MRI remains important diagnostic tool for evaluation of vertigo and MRA is necessary when vascular origin is suspected.

Role of Magnetic Resonance Angiography in Evaluation of Brain Pathologies

Background: MR angiography is the latest technique for the evaluation of cerebrovascular diseases. It is now used commonly for the evaluation of brain pathologies. The advantage is it is a non-invasive method of brain vasculature. The present study aimed to evaluate the role of Magnetic Resonance Angiography in the detection of brain pathologies and to study the Role of Magnetic Resonance Angiography in Cerebral Arteriovenous Malformations, Aneurysms, and Cerebral infarctions. Methods: Data for the study was collected from patients with clinically suspected cerebral lesions or from patients, in whom previous images depicted cerebral lesions, undergoing MRA for evaluation of cerebral lesions Patients underwent MR imaging including TOF Magnetic resonance angiography according to the set protocols after obtaining informed consent. All these patients had undergone detailed clinical evaluation by the referring neurosurgery unit. Results: In this study, a total of n=32 cases were included out of which n=6(18.75%) were AVM, n=10(31.25%) were Aneurysms, and n=16(50%) were cases of infarcts. Of the total n=16 infarct cases n=8(50%) were found in the middle cerebral artery (MCA) n=4(25%) in ACOM and n=2 in PCOM, as well as Internal carotid artery (ICA). Of the MCA cases n=5(62.5%) were right-sided and n=3(37.5%) were left-sided. Conclusion: MRA is now in routine use as a non-invasive tool for imaging the cerebralvasculature. In cerebrovascular disease, it is the investigation of choice forpatients who are suspected/ increased risk of having unruptured intracranial aneurysms, and intracranial vascular disease associated with acute infarction ,intracranial dissection of the carotid and/or vertebral arteries, and follow up cases of Cerebral AVMs.

Evaluation of magnetic resonance angiography as a possible alternative to rotational angiography or computed tomography angiography for assessing cerebrovascular computational fluid dynamics.

The aim of this study was to conduct a flow experiment using a cerebrovascular phantom and investigate whether magnetic resonance angiography (MRA) could replace three-dimensional rotational angiography (RA) and computed tomography angiography (CTA) to construct vascular models for computational fluid dynamics (CFD). We performed MRA and 3D cine phase-contrast (PC) MR imaging with a silicone cerebrovascular phantom of an internal carotid artery-posterior communicating artery aneurysm with blood-mimicking fluid, and controlled flow with a flowmeter. We also obtained RA and CTA data for the phantom. Four analysts constructed vascular models based on the three different modalities. These 12 constructed models used flow information based on 3D cine PC MR imaging for CFD. We compared RA-, CTA-, MRA-based CFD results using the micro-CT-based CFD result as the criterion standard to investigate whether MRA-based CFD was not inferior to RA- or CTA-based CFD. We also analyzed the inter-analyst variability. Wall shear stress (WSS) distributions and streamlines of RA- or MRA-based CFD and those of micro-CT-based CFD were similar, but the vascular models and WSS values were different. Accuracy in measurements of blood vessel diameter, cross-sectional maximum velocity, and spatially averaged WSS was the highest for RA-based CFD, followed by MRA-based and CTA-based CFD using micro-CT-based CFD result as the reference. Except maximum velocity from CTA, all other parameters had good inter-analyst agreement using different modalities. The results demonstrated that non-invasive MRA can be used for cerebrovascular CFD models with good inter-analyst agreements.

Clinical Features and Treatment Strategy of Vertebral Artery Injury Associated with Cervical Spine Trauma

Vertebral artery injury(VAI)associated with cervical spine trauma has the potential to cause catastrophic vertebrobasilar stroke. However, there are no well-defined treatment recommendations for VAI. The purpose of this study was to identify an effective treatment strategy for VAI following cervical spine trauma. Ninety-seven patients with blunt cervical spine trauma were treated at Hyogo Prefectural Kakogawa Medical Center between January 2013 and September 2017. Of these patients, 49 underwent computed tomographic angiography or magnetic resonance angiography for evaluation of the vertebral artery. Eighteen patients(36.7%)had a diagnosis of VAI. We retrospectively analyzed the clinical features, treatment, and outcomes in these 18 patients. Seven patients(38.9%)had bilateral VAI, 16(88.9%)had cervical dislocation, and 2(11.1%)had transverse process fractures extending into the transverse foramen. Surgical reduction was performed in 14 patients. Five patients with either bilateral or unilateral occlusion underwent parent artery occlusion before reduction. There were no complications after this procedure. Two patients with bilateral VAI had a stroke before treatment. There were no infarctions in the distribution of the vertebrobasilar artery after intervention. The perioperative stroke rate was relatively good, and almost all Glasgow Outcome Scale scores were related to the degree of spinal cord injury. Aggressive screening for VAI is important in patients with cervical spine trauma in order to ensure adequate treatment. Although the treatment strategy described here could yield good results, it may require modification according to the needs of the individual patient.

Magnetic resonance angiography in evaluation of acute intracranial steno-occlusive arterial disease

ObjectivesAssessment of the diagnostic usefulness of MRA in evaluation of patients with acute intra cranial steno-occlusive arterial disease. Patients and methods84 patients with acute intracranial steno-occlusive arterial disease were subjected to the following brain MRI protocol: Axials DWI, T1WI, T2WI, FLAIR, T2∗ Gradient Echo Imaging and 3D TOF MRA. ResultsEighty four patients (M/F=49/35) aged between 28 and 86years. MRA findings of arterial segments correlated with location of the ischemic lesions described by different MRI sequences including the DWI in all cases (100%). MRA of the intracranial vessels revealed 60 arterial segments with occlusions/absent flow. Occlusions were most common in MCAs (n=45) followed by PCAs (n=9). 31 arterial segments with stenosis were seen, and they were mainly affecting arterial territories of PCAs (n=16). Atheromatous plaques were identified at the Lt. ICA in 3 cases and in Rt. ICA in 2 cases, absent A1 segment of Rt. ACA (n=12), absent A1 segment of Lt. ACA (n=2), dominant Rt. VA (n=6), dominant Lt. VA (n=4) and Dolichoectasia of BA (n=4). ConclusionsMRA provides early detailed diagnosis of occlusive intracranial arterial disease through detection of exact site of arterial affection.

Time-resolved magnetic resonance angiography (MRA) at 3.0 Tesla for evaluation of hemodynamic characteristics of vascular malformations: description of distinct subgroups.

Quantitative evaluation of hemodynamic characteristics of arteriovenous and venous malformations using time-resolved magnetic resonance angiography (MRA) at 3.0 Tesla. Time-resolved MRA with interleaved stochastic trajectories (TWIST) at 3.0 Tesla was studied in 83 consecutive patients with venous malformations (VM) and arteriovenous malformations (AVM). Enhancement characteristics were calculated as percentage increase of signal intensity above baseline over time. Maximum percentage signal intensity increase (signalmax), time intervals between onset of arterial enhancement and lesion enhancement (tonset), and time intervals between beginning of lesion enhancement and maximum percentage of lesion enhancement (tmax) were analyzed. All AVMs showed a high-flow hemodynamic pattern. Two significantly different (p < 0.001) types of venous malformations emerged: VMs with arteriovenous fistulas (AVF) (median signalmax 737%, IQR [interquartile range] = 511 - 1182%; median tonset 5s, IQR = 5 - 10s; median tmax 35s, IQR = 26 - 40s) and without AVFs (median signalmax 284%, IQR = 177-432%; median tonset 23s, IQR = 15 - 30s; median tmax 60s, IQR = 55 - 75s). Quantitative evaluation of time-resolved MRA at 3.0 Tesla provides hemodynamic characterization of vascular malformations. VMs can be subclassified into two hemodynamic subgroups due to presence or absence of AVFs. • Time-resolved MRA at 3.0 Tesla provides quantitative hemodynamic characterization of vascular malformations. • Malformations significantly differ in time courses of enhancement and signal intensity increase. • AVMs show a distinctive high-flow hemodynamic pattern. • Two significantly different types of VMs emerged: VMs with and without AVFs.

Magnetic resonance angiography evaluation of the bone tunnel and graft following ACL reconstruction with a hamstring tendon autograft.

In this study, magnetic resonance angiography (MRA) was performed in the early phase after anterior cruciate ligament (ACL) reconstruction to analyse the changes in nutrient blood vessels and blood flow to the femoral and tibial tunnels and the intraosseous tendon grafts. The subjects were 30 patients who underwent single-bundle ACL reconstruction with an autogenous hamstring tendon. MRA was performed at 2, 3, and 6 months postoperatively (n = 10 at each time point). The mean overall signal-to-noise ratios (SNRs) in the tunnel regions and in the region of the tendon graft were compared in each femur and tibia. Blood vessels from arteries reached the femoral and tibial tunnels 2 months postoperatively. The tunnel walls showed high signal intensity, while the intraosseous tendon grafts had lower intensity. SNRs showed significant differences between the femoral and tibial tunnels overall and the intraosseous tendon grafts. At 3 and 6 months postoperatively, the signal intensity of the tunnel walls was decreased significantly, while that of the intraosseous tendon grafts was also decreased, but not significantly. At these times, the SNRs of the femoral and tibial tunnels did not differ significantly, both overall and in the region of the intraosseous tendon grafts. Revascularization around the femoral and tibial tunnels occurred at 2 months postoperatively, with blood flow subsequently decreasing over time until 6 months. This revascularization may be involved in bone tendon healing and maturation of the tendon graft within the bone tunnels. Evaluations of revascularization by MRA may show the maturation stage of the graft and guide medical rehabilitation. IV.

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Feraheme-Enhanced Magnetic Resonance Angiography Evaluation of DIEP Flap Vasculature

Feraheme-Enhanced Magnetic Resonance Angiography Evaluation of DIEP Flap Vasculature

Magnetic resonance angiography in reversible cerebral vasoconstriction syndromes

To investigate the evolution and clinical significance of vasoconstriction on magnetic resonance angiography (MRA) in patients with reversible cerebral vasoconstriction syndromes (RCVS). Patients with RCVS were recruited and followed up with MRA examinations until normalization of vasoconstriction or for 6 months. The vasoconstriction severity of the major cerebral arterial segments (M1, M2, A1, A2, P1, P2, and basilar artery) was scored on a 5-point scale: 0 (0-<10%), 1 (10-<25%), 2 (25-<50%), 3 (50-<75%), and 4 (> or =75%). Subjects with at least 1 segment with a vasoconstriction score > or =2 were eligible for the study. Initial mean scores of single or combined arterial segments were used to predict ischemic complications. Seventy-seven patients with RCVS (8 men/69 women; average age 47.7 +/- 11.6 years) finished the study with a total of 225 MRAs performed. The mean number of arterial segments involved was 5.3 +/- 3.0 in the initial MRA. Vasoconstriction scores reached their maximum 16.3 +/- 10.2 days after headache onset, close to the average timing of headache resolution (16.7 +/- 8.6 days). Vasoconstriction evolved in a parallel trend among different arterial segments. Seven (9.1%) patients developed posterior reversible encephalopathy syndromes (PRES). Six (7.8%) patients had ischemic stroke. A logistic regression model demonstrated that the M1-P2 combined score was associated with highest risk of PRES (odds ratio [OR], 11.6, p = 0.005) and ischemic stroke (OR, 3.4; p = 0.026). MRA evaluation in patients with RCVS is valid. Vasoconstriction was pervasive and outlasted headache resolution. Vasoconstrictions in M1 and P2 are important determinants for PRES and ischemic stroke.

Clinical Role of Non-Contrast Magnetic Resonance Angiography for Evaluation of Renal Artery Stenosis

The association between a gadolinium-based contrast material and nephrogenic systemic fibrosis has been discussed. The purpose of our study was to evaluate whether non-contrast enhanced magnetic resonance angiography (MRA) might provide sufficient information of renal artery stenosis. The non-contrast MRA of 26 patients with hypertension was retrospectively reviewed in the present study. The significant renal artery stenosis was visually evaluated by comparing non-contrast MRA with computed tomography or conventional angiographic finding. Difference of the intensities between the proximal and distal aorta was quantitatively evaluated. The sensitivity, specificity, positive predictive value and negative predictive value of non-contrast MRA in the evaluation of the renal artery stenosis was 78%, 91%, 64% and 96%, respectively. The distal abdominal aorta showed less signal intensity than the proximal aorta by 16.9+/-12.2%. Non-contrast MRA is a non-invasive and effective method that allows evaluation of the renal artery stenosis.

A multi-center, comparative, phase 3 study to determine the efficacy of gadofosveset-enhanced magnetic resonance angiography for evaluation of renal artery disease

PurposeTo determine prospectively the safety and efficacy of the blood-pool contrast agent gadofosveset trisodium in renal artery magnetic resonance angiography (MRA). Materials and methodsGadofosveset (0.03mmol/kg) was administered to adult patients with known or suspected renal arterial disease in a multi-center phase 3 single dose study. The drug binds reversibly to albumin, prolonging the blood residence time, and allowing collection of images in the first-pass and steady-state phases. The combination of these images was compared to non-contrast MRA, using catheter X-ray angiography (XRA) as the standard of reference (SOR). All MRA images were collected at 1.5T in one imaging session for direct comparison, and XRA within 30 days. Sensitivity, specificity, and accuracy for diagnosing significant disease (stenosis ≥50%) were calculated for MRA using three independent blinded readers. Patient safety was monitored for 72–96h. ResultsA total of 145 patients at 18 centers were enrolled and received gadofosveset; the 127 with complete efficacy data entered the primary efficacy analysis. Gadofosveset-enhanced MRA led to significant improvement (p<0.01) in sensitivity (+25%, +26%, +42%), specificity (+23%, +25%, +29%), and accuracy (+23%, +28%, +29%) over non-enhanced MRA for the three readers. The rate of uninterpretable examinations decreased from 30% to less than 2%. There were no serious adverse events, and the most common adverse events were nausea, pruritis, and headache (8% each). No significant trends in clinical chemistry parameters, nor significant changes in serum creatinine, were found following administration of gadofosveset. ConclusionIn patients with known or suspected renal arterial disease, multi-phase gadofosveset-enhanced MRA significantly improves sensitivity, specificity, and accuracy versus non-enhanced MRA. Gadofosveset was safe and well tolerated in this patient population.

The Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) Trial

Transcranial Doppler ultrasound (TCD) and magnetic resonance angiography (MRA) can identify intracranial atherosclerosis but have not been rigorously validated against the gold standard, catheter angiography. The WASID trial (Warfarin Aspirin Symptomatic Intracranial Disease) required performance of angiography to verify the presence of intracranial stenosis, allowing for prospective evaluation of TCD and MRA. The aims of Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) trial were to define abnormalities on TCD/MRA to see how well they identify 50 to 99% intracranial stenosis of large proximal arteries on catheter angiography. SONIA standardized the performance and interpretation of TCD, MRA, and angiography. Study-wide cutpoints defining positive TCD/MRA were used. Hard copy TCD/MRA were centrally read, blind to the results of angiography. SONIA enrolled 407 patients at 46 sites in the United States. For prospectively tested noninvasive test cutpoints, positive predictive values (PPVs) and negative predictive values (NPVs) were TCD, PPV 36% (95% CI: 27 to 46); NPV, 86% (95% CI: 81 to 89); MRA, PPV 59% (95% CI: 54 to 65); NPV, 91% (95% CI: 89 to 93). For cutpoints modified to maximize PPV, they were TCD, PPV 50% (95% CI: 36 to 64), NPV 85% (95% CI: 81 to 88); MRA PPV 66% (95% CI: 58 to 73), NPV 87% (95% CI: 85 to 89). For each test, a characteristic performance curve showing how the predictive values vary with a changing test cutpoint was obtained. Both transcranial Doppler ultrasound and magnetic resonance angiography noninvasively identify 50 to 99% intracranial large vessel stenoses with substantial negative predictive value. The Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis trial methods allow transcranial Doppler ultrasound and magnetic resonance angiography to reliably exclude the presence of intracranial stenosis. Abnormal findings on transcranial Doppler ultrasound or magnetic resonance angiography require a confirmatory test such as angiography to reliably identify stenosis.

3 T Contrast-Enhanced Magnetic Resonance Angiography for Evaluation of the Intracranial Arteries

We sought to prospectively evaluate the image quality and visualization of the intracranial arteries using high spatial resolution contrast-enhanced magnetic resonance angiography (CE-MRA) at 3 T and to perform intraindividual comparison with time-of-flight (TOF) MRA and multislice CT angiography (CTA). Twelve patients (5 men, 7 women, 37-71 years of age) with suspected cerebrovascular disease prospectively underwent MRA and CTA. MRA was performed on a 3 T MR system, including both 3-dimensional (3D) TOF (Voxel dimension: 0.6 x 0.5 x 0.9 mm in 5 minutes and 40 seconds) and 3D CE-MRA (voxel dimension: 0.7 x 0.7 x 0.8 mm in 20 seconds, using parallel acquisition with an acceleration factor of 4). CTA images were acquired on a 16-slice CT scanner (voxel dimension: 0.35 x 0.35 x 0.8 mm in 17 seconds). The image quality and visualization of up to 26 intracranial arterial segments in each study was evaluated by 2 experienced radiologists. The arterial diameter for selective intracranial arteries was measured independently on each of the 3 studies, and statistical analysis and comparative correlation was performed. A total of 312 arterial segments were examined by CE-MRA, TOF-MRA, and CTA. The majority of intracranial arteries (87%) were visualized with diagnostic image quality on CE-MRA with a significant correlation to TOF (R values = 0.84; 95% confidence interval 0.79-0.86, P < 0.0001), and to CTA (R values = 0.74; 95% confidence interavl 0.68-0.78, P < 0.001). The image quality for small intracranial arteries, including the anterior-inferior cerebellar artery, the posterior communicating artery, and the M3 branch of the middle cerebral artery, was significantly lower on CE-MRA compared with TOF and CTA (P < 0.03). There was a significant correlation for the dimensional measurements of arterial diameters at CE-MRA with TOF (r = 0.88, 95% confidence interval 0.81-0.93), and CTA (r = 0.83, 95% confidence interval 0.73-0.90). The described 3 T CE-MRA protocol, spanning from the cervical to the intracranial vessels, visualized and characterized the majority of intracranial arteries with image quality comparable with that obtained using TOF-MRA and CTA. Further clinical studies are required to establish the accuracy of the technique in a broader clinical setting.

Magnetic resonance (MR) imaging and MR angiography for evaluation and follow-up of hepatic artery banding in patients with hepatic involvement of hereditary hemorrhagic telangiectasia

We describe findings obtained by magnetic resonance angiography (MRA) and magnetic resonance imaging (MRI) for evaluation and follow-up after hepatic artery banding in patients with hepatic involvement of hereditary hemorrhagic telangiectasia (HHT). Abdominal MRA and liver MRI were performed in three patients with HHT as clinically defined by Curacao criteria. One patient underwent MRA and MRI twice for preinterventional evaluation and follow-up, one patient for preinterventional evaluation, and one patient for postinterventional evaluation. Hepatic vascular involvement of the disease and postinterventional vascular anatomy were evaluated by two radiologists by consensus. Hepatic vascular involvement with perfusion disorders and arteriosystemic shunts was found in all three patients. MRA and MRI allowed diagnostic characterization of hepatic vascular disease (three of three), preinterventional evaluation of complex vascular anatomy and variants (two of two), and postinterventional follow-up of hepatic artery banding (two of two). In preinterventional evaluation and postinterventional follow-up, MRA and MRI allows characterization of complex hepatic vascular alterations of HHT and, hence, is an alternative to other imaging modalities in the diagnosis, clinical decision making, and follow-up of HHT.

MR Angiography Compared to Conventional Selective Angiography in Acute Stroke

Accuracy of intracranial magnetic resonance angiography (MRA) and reliability of interpretation are not well established compared to conventional selective catheter angiography. The purpose of this study was to determine the accuracy of MRA in evaluation of intracranial vessels in acute stroke and transient ischemic attack (TIA) patients Twenty-nine patients (seven females, 22 males; median age 53) with acute stroke or TIA were enrolled into the study. All patients underwent both MRA using a 3 T clinical magnet and conventional angiography within 48 hours. Median time between MRA and angiography was 263 minutes. Conventional angiography preceded MRA in 15 cases. Fourteen patients received thrombolysis during MRA or angiography. National Institutes of Health Stroke Scale scores were obtained prior to the MR exam. One neuroradiologist rated all conventional angiograms, which were used as gold standard. Five observers, blinded to conventional angiography results and all clinical information except symptom side, rated the MR angiograms. Kappa statistics were used to assess reliability; contingency tables were used to assess accuracy of non-enhanced and enhanced MRA. Two hundred and fifty two intracranial vessels were assessed. Agreement between raters was good for both non-enhanced (kappa = 0.50) and gadolinium-enhanced (kappa = 0.46) images. There were a total of 26 vessels occluded by DSA. Overall, the non-enhanced MRA showed sensitivity of 84.2% (95% CI 60.4-96.6) and specificity of 84.6% (95% CI 78.6-89.4). The enhanced MRA showed sensitivity of 69.2 (95% CI 38.6-90.9) and specificity of 73.6 (95% CI 65.5-80.7). Magnetic resonance angiography is a good non-invasive screening tool for assessing intracranial vessel status in acute ischemic stroke. Angiography remains the gold standard for definitive assessment of the intracranial circulation.

Magnetic resonance angiography evaluation of external carotid artery tributaries in moyamoya disease

Background and Purpose High-resolution magnetic resonance (MR) image has been introduced to diagnose and follow-up moyamoya disease and visualized moyamoya vessels and internal carotid artery stenosis. This study was performed to assess the utility of MR angiography (MRA) for the evaluation of anastomotic channels through the external carotid artery (ECA) in moyamoya disease patients. Methods Twenty patients with moyamoya disease were reviewed. The cortical anastomosis and superficial temporal artery (STA), middle meningeal artery, and deep temporal artery by MRA were evaluated and were compared with those by digital subtraction angiography if obtained. Fifteen patients (24 hemispheres) underwent bypass surgery, including encephaloduroarteriosynangiosis in 14 hemispheres and STA–middle cerebral artery anastomosis with encephalomyosinangiosis in 10 hemispheres. Five patients did not undergo any surgery. Results MRA could show these vessels and the patency of anastomosis formed by the surgery and also showed naturally formed anastomosis and ECA tributaries in the patients who did not undergo any surgery. Conclusion MRA provides useful information for follow-up evaluation on the development of the ECA system in moyamoya disease.

Magnetic resonance angiographic localization of the artery of Adamkiewicz for spinal cord blood supply

Background The purpose of this study was to determine whether the artery of Adamkiewicz (ARM) can be detected by magnetic resonance angiography and to determine the usefulness of preoperative magnetic resonance angiography evaluation of the ARM. Methods Between April 2000 and December 2003, 120 patients underwent magnetic resonance angiography for detection of the ARM. The morphology of the anterior spinal artery at the ARM junction, as revealed by magnetic resonance angiography, in 99 patients in whom ARM was preoperatively detected was classified into the following three types: noncontinuation of the anterior spinal artery above the ARM junction (type A), continuation of the anterior spinal artery above and below the ARM junction (type B), and noncontinuation of the anterior spinal artery below the ARM junction (type C). Results The ARMs were detected in 99 (83%) of 120 patients, and from a total of 110 ARMs 105 (95%) originated from intercostal arteries branching from the left side and 94 (86%) originated between Th9 and Th11. Two ARMs were found in 11 (11%) of 99 patients in whom ARMs were detected. In 107 patients, who underwent magnetic resonance angiography to reveal the morphology of the anterior spinal artery at the ARM junction, the patterns of the anterior spinal artery were type A in 59 patients (55%), type B in 21 patients (20%), type C in 3 patients (3%) and not classified in 24 patients (22%). No spinal cord injury occurred in patients in whom the ARM had been preoperatively detected. Conclusions Preoperative detection of the ARM is possible by magnetic resonance angiography and is very useful for reducing the incidence of ischemic injury of the spinal cord.

Magnetic resonance angiography for preoperative evaluation of potential kidney donors 1

Background Careful evaluation of the renovascular anatomy for living kidney donors is essential to optimize donor and recipient outcomes. Arteriography has been the standard for delineating the renovascular anatomy. However, this procedure is invasive. Magnetic resonance angiography (MRA) is an attractive, noninvasive alternative. The aim of this study was to evaluate the accuracy of MRA in potential living kidney donors. Methods A retrospective comparison of the preoperative MRA results with the intraoperative anatomy was performed in 189 living kidney donors. Results MRA interpretations correctly identified the vascular anatomy of the donor kidneys in 173 donors (91.5%). In the remaining 16 patients (8.5%), the MRA interpretation was inaccurate. In 10 patients, the MRA reported fewer arteries than the number encountered during the donor operation, whereas in six patients MRA reported more arteries than what found during operation. In seven patients, MRA supplied additional important anatomical information, including kidney size disparity, the presence of nephrolithiasis, the presence of a renal cyst, and renal artery stenosis. All kidneys were successfully transplanted. The misinterpretation of the MRA did not adversely affect the recipient outcome. Conclusion The noninvasive MRA evaluation of donor renovascular anatomy is an acceptable substitute for traditional angiography.