Magnetic Resonance Digital Subtraction Angiography Research Articles

MR Selective Flow-Tracking Cartography: A Postprocessing Procedure Applied to Four-dimensional Flow MR Imaging for Complete Characterization of Cranial Dural Arteriovenous Fistulas

Purpose To assess the feasibility of a selective flow-tracking cartographic procedure applied to four-dimensional (4D) flow imaging and to demonstrate its usefulness in the characterization of dural arteriovenous fistulas (DAVFs). Materials and Methods Institutional review board approval was obtained, and all patients provided written informed consent. Eight patients (nine DAVFs) underwent 3.0-T magnetic resonance (MR) imaging and digital subtraction angiography (DSA). Imaging examinations were performed within 24 hours of each other. 4D flow MR imaging was performed by using a 4D radial phase-contrast vastly undersampled isotropic projection reconstruction pulse sequence with an isotropic spatial resolution of 0.86 mm (5 minutes 35 seconds). Two radiologists independently reviewed images from MR flow-tracking cartography and reported the location of arterial feeder vessels and the venous drainage type and classified DAVFs according to the risk of rupture (Cognard classification). These results were compared with those at DSA. Quadratic weighted κ statistics with their 95% confidence intervals (CIs) were used to test intermodality agreement in the identification of arterial feeder vessels, draining veins, and Cognard classification. Results Interreader agreement for shunt location on MR images was perfect (κ = 1), with good-to-excellent interreader agreement for arterial feeder vessel identification (κ = 0.97; 95% CI = 0.92, 1.0), and matched in all cases with shunt location defined at DSA. There was good-to-excellent agreement between MR cartography and DSA in the definition of the main feeding arteries (κ = 0.92; 95% CI = 0.83, 1.0), presence of retrograde flow in dural sinuses (κ = 1), presence of retrograde cortical venous drainage (κ = 1), presence of venous ectasia (κ = 1), and final Cognard classification of DAVFs (κ = 1, standard error = 0.35). Conclusion MR selective flow-tracking cartography enabled the noninvasive characterization of cranial DAVFs. © RSNA, 2013 Online supplemental material is available for this article.

Treatment of Giant and Large Fusiform Middle Cerebral Artery Aneurysms With Excision and Interposition Radial Artery Graft in a 4-Year-Old Child

We report an unusual case of complex giant and large fusiform aneurysms not amenable for clipping or coiling in a 4-year-old child managed with aneurysm resection and radial artery interposition graft. A 4-year-old child presented with repeated severe headache and vomiting. Computed tomography, magnetic resonance imaging, and magnetic resonance angiography and digital subtraction angiography showed a giant fusiform aneurysm on the right middle cerebral artery (MCA). Because of the complex shape, endovascular treatment or clip reconstruction was not possible, and a bypass procedure was planned. Right frontotemporal craniotomy and orbitotomy was performed. Two aneurysms involving the M1 segment of the MCA were found in line, 1 giant, and the other large in size. The aneurysms were resected and treated with short radial artery interposition graft, which was narrower than the proximal or distal MCA. The child recovered normally, and the bypass was patent after 1 year. Large fusiform MCA aneurysms may be difficult to treat, but there are treatment options that include a bypass procedure. Resection and short interposition radial artery graft is an excellent but rare treatment option in a very young child. This was a very successful treatment in this child.

A single-site retrospective study of pediatric arterial ischemic stroke etiology, clinical presentation, and radiologic features

Background Stroke occurs upon obstruction of cerebral blood circulation and is clinically characterized by sudden onset symptoms. Advanced age is the main risk factor of stroke, but cases of pediatric stroke have been rarely reported. This study aimed to determine the etiology, clinical presentation, and radiologic features of neurological deficit for pediatric arterial ischemic stroke (PAIS). Methods The medical records of 42 PAIS patients (age range: 9 months to 13 years) treated at Wuhan Children's Hospital between July 2007 and January 2011 were retrospectively reviewed. Infarction location was first determined by craniocerebral computed tomography and magnetic resonance (MR) imaging. The stenotic or occluded main cerebral arteries and/or branches were determined by MR angiography and digital subtraction angiography. Results The majority of the 42 PAIS cases (66.7%, n=28) were ≤3 years old (vs. >3 years old: 33.3%, n=14; P<0.05), but the male: female ratio was similar in both groups (P>0.05). The most frequently reported signs and symptoms for both age groups were limited physical activity followed by convulsions and delirium, but convulsions were more prevalent in children ≤3 years-old. Children>3 years-old mainly experienced the limited physical activity symptoms, including hemiparalysis, aphasia, and ataxia. For all 42 cases, the most frequent etiologies were infections (38.1%, n=16), iron deficiency anemia (16.7%, n=7), and moyamoya syndrome (11.9%, n=5). The predominant infarcts among all cases were middle cerebral artery (63.6%, n=21) and basal ganglia (64.3%, n=27). Conclusions PAIS occurs more frequently in younger children and this group most frequently presents with convulsion as the initial symptom. The overall etiologies of PAIS may be different from those of adult stroke and the involved regions may be distinguishing features of PAIS or its different forms, but more research is required.

TOAST classification of isolated pontine infarction

Background Through the analysis of various imaging and angiography data, including computed tomography angiography (CTA), magnetic resonance angiography (MRA) and digital subtraction angiography (DSA), this article aims to understand the relation between pontine infarction and posterior circulation lesions, classify different types of causes of isolated pontine infarction, and compare the clinical characteristics of different classification methods. Methods Eighty-five cases with first-onset isolated pontine infarction were selected. On the basis of imaging examinations, they were divided into the following categories: vertebrobasilar large-artery disease (VLAD); basal artery branch disease (BABD); small artery disease (SAD); type of other reasons and type of uncertain causes. According to Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification standard, all patients were divided into the following categories: large artery atherosclerosis (LAA), small artery occlusion (SAO), cardiac embolism (CE), stroke of other determined etiology (SOE), stroke of undetermined etiology (SUE). Results According to imaging classification, BABD was the most common type, accounting for 50.59% (43/85); SAD accounted for 28.23% (24/85); VLAD accounted for 14.12% (12/85); type of uncertain causes accounted for 7.06% (6/85); type of other reasons was not found. Based on the TOAST classification, SAO was the most common type, accounting for 67.06% (57/85); LAA accounted for 30.59% (26/85); SUE accounted for 2.35% (2/85); CE and SOE were not found. Conclusion Based on the TOAST classification, small artery occlusion is the most common etiology of isolated pontine infarction. It is favorable for formulating specific treatment to make TOAST classification based on a variety of imaging data.

Abstract WP231: Detection of Intramural Hematoma by Susceptibility Weighted Image in Vertebral Artery Dissection

Objectives The radiologic diagnosis of vertebral artery dissection (VAD) depends on the characteristic intraluminal findings on angiographic study although the pathology of VAD is intramural hematoma. We aimed to know whether ‘intramural hematoma sign (IHS)’ on susceptibility weighted image (SWI) in vertebral artery is specific for VAD. Methods We retrospectively analyzed SWI and phase map images of the consecutive patients with ischemic stroke in the vertebral artery territory from August 2009 to July 2012. We divided the patients into 2 groups; VAD related stroke and atherosclerotic stroke. Diagnostic criteria of VAD related stroke were (a) presence of posterior neck pain or occipital headache and (b) features of VAD at computed tomography angiography or contrast enhanced magnetic resonance angiography or digital subtraction angiography. Angiographic evidence of VAD which is subdivided into three groups: aneurysmal dilatation without stenosis, pearl-and string, and steno-occlusive without aneurysmal dilatation. IHS was considered positive if the patient had (a) eccentric hypointense signal lesion in vertebro-basilar artery on SWI and (b) this signal should be hyperintense on phase map suggesting blood products other than calcification. An experienced neuroradiologist blinded to clinical information was asked to judge the presence of IHS. For statistical analysis, two by two contingency tables by Fisher’s exact test were performed. Results Among the 137 patients with ischemic stroke in the vertebral artery territory, SWI and phase map images were available in 47 patients who were included for our analysis. Among them, 14 patients were diagnosed as an ischemic stroke due to VAD and 33 patients had no VAD (atherosclerotic stroke). Compared to atherosclerotic stroke patients, patients with VAD-related stroke had more headache (64% vs 15%, P=0.016). Among the 14 patients with VAD-related stroke, IHS was detected in 9 cases while only 2 of 33 patients with atherosclerotic stroke showed IHS (sensitivity 64% and specificity 94%). In Fisher’s exact test analysis, the IHS was significantly associated with VAD (p < 0.001). Conclusion The intramural hematoma sign on SWI was significantly associated with vertebral artery dissection.

Comparison of contrast‐enhanced multi‐station MR angiography and digital subtraction angiography of the lower extremity arterial disease

To compare diagnostic accuracy of multi-station, high-spatial resolution contrast-enhanced MR angiography (CE-MRA) of the lower extremities with digital subtraction angiography (DSA) as the reference standard in patients with symptomatic peripheral arterial occlusive disease. Of 485 consecutive patients undergoing a run-off CE-MRA, 152 patients (86 male, 66 female; mean age, 71.6 years) with suspected peripheral arterial occlusive disease were included into our Institutional Review Board approved study. All patients underwent MRA and DSA of the lower extremities within 30 days. MRA was performed at 1.5 Tesla with a single bolus of 0.1 mmol/kg body weight of gadobutrol administered at a rate of 2.0 mL/s at three stations. Two readers evaluated the MRA images independently for stenosis grade and image quality. Sensitivity and specificity were derived. Sensitivity and specificity ranged from 73% to 93% and 64% to 89% and were highest in the thigh area. Both readers showed comparable results. Evaluation of good and better quality MRAs resulted in a considerable improvement in diagnostic accuracy. Contrast-enhanced MRA demonstrates good sensitivity and specificity in the investigation of the vasculature of the lower extremities. While a minor investigator experience dependence remains, it is standardizable and shows good inter-observer agreement. Our results confirm that the administration of Gadobutrol at a standard dose of 0.1 mmol/kg for contrast-enhanced runoff MRA is able to detect hemodynamically relevant stenoses. Use of contrast-enhanced MRA as an alternative to intra-arterial DSA in the evaluation and therapeutic planning of patients with suspected peripheral arterial occlusive disease is well justified.

Zerebrale Gefäßdiagnostik – Bildgebung

Imaging of the cerebral vasculature relies mostly on computed tomography angiography (CTA), magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). Although DSA is still the gold standard, many questions can be answered with CTA and/or MRA thanks to recent technological advances. The following article describes the advantages and disadvantages of these techniques with regard to different questions. Basic principles regarding the different techniques are explained.

Peripheral Arterial Occlusive Disease: 3.0-T versus 1.5-T MR Angiography Compared with Digital Subtraction Angiography

To prospectively evaluate the diagnostic accuracy of 3-T versus 1.5-T contrast material-enhanced (CE) magnetic resonance (MR) angiography with high spatial resolution in patients who have peripheral arterial occlusive disease, with conventional digital subtraction angiography (DSA) serving as the reference standard. Institutional review board approval and written informed consent were obtained. DSA and standardized single-injection, three-station, moving-table CE MR angiography, with similar acquisition protocols and contrast agent doses at 3 T and 1.5 T, were consecutively performed in 19 patients (13 men and six women; mean age ± standard deviation, 67 years ± 9). Stenosis was scored visually in 500 arterial segments (97.5% of all available) in consensus by two radiologists in a blinded manner (the radiologists were unaware of the field strength and prior DSA and MR angiographic results and used randomized analysis order). Contrast-to-noise ratio was determined in the vascular tree of both legs. Statistical significance in stenosis scoring was evaluated by using generalized estimating equations. Contrast-to-noise differences were evaluated with paired t tests. Agreement between MR angiography and DSA was evaluated by using Fleiss-Cohen κ statistics. Both 3-T and 1.5-T CE MR angiography showed similar excellent agreement with DSA regarding stenosis classification (κ = 0.96 and 0.93, respectively). All sensitivity and specificity values exceeded 90%. Mean contrast-to-noise ratio was 3.0-4.2 times higher at 3 T than at 1.5 T. Standardized single-injection, three-station, moving-table 3-T CE MR angiography is reliable for classification of stenosis in patients suspected of having peripheral arterial occlusive disease, and diagnostic performance was similar to that seen with 1.5-T MR angiography. There was a significantly increased contrast-to-noise ratio for identical contrast agent dose at 3-T MR angiography.

Causes and counter measures of reoperation for biliary diseases

The reoperation for biliary diseases is usually unplanned, and the major reasons leading to this situation include:(1) The initial operation was performed under emergency situation and radical procedure could not be carried out.(2) The surgical procedure was inadequate.( 3 ) The operator was unqualified for the operation. In order to avoid repeated operations,the following principles must be obeyed strictly.Firstly,once the initial operation was failed,the patients must be transferred to large medical center and the reoperation must be performed by hepatobiliary specialists.Secondly,the operator must realize that most of the patients were in poor condition because of the previous operation,and they needed careful evaluation of organ function and adequate supportive treatment before reoperation.Thirdly,various measures must be taken to avoid unplanned operation and ensure the successful implement of radical operation at a time:( 1 ) Operator must learn all the details of previous operation,which include operation procedure,findings during operation and postoperative complications.( 2 ) Cholangiogram of the whole biliary tree is important for surgical planning,ultrasonography,computed tomography (CT),endoscopic retrograde cholangiopancreatography,magnetic resonance cholangiopancreatography, percutaneous transhepatic cholangiography (PTC),or PTC-CT should be performed solely or comprehensively to determine the nature and location of lesions.For bile duct injury,additional examination including CT angiography,magnetic resonance angiography or digital subtraction angiography is necessary to ascertain the accompanied vessel injury.(3) Making individual surgical procedure according to patien's condition and distribution of lesions. Key words: Biliary surgery; Reoperation; Counter measure

Multichannel fenestration of the petrous and cavernous segments of the internal carotid artery associated with two small carotid canals

A fenestration is defined as a division of the arterial lumen into distinctly separate channels, each with its own endothelial and muscularis layers, while the adventitia may be shared. Duplication, by contrast, is defined as two distinct arteries with separate origins and no distal arterial convergence. Fenestrations can range from a small focus of divided tissue to long segment duplications. They are the result of partial failure of fusion of paired primitive embryologic vessels or incomplete obliteration of different anastomosis in a primitive vascular network [1]. Fenestration, or duplication, of the internal carotid artery (ICA) is considered as an extremely rare anatomic variant. The prescens of greater than two channels in a long segment of the ICA has not been previously described. We report a case of multichannel fenestrations of the petrous and cavernous segments of the ICA associated with two small carotid canals. A 58-year-old man with no remarkable medical history was admitted to the Department of Neurology for transient ischemic attack involving the right upper extremity. At admission, his general and neurologic examinations were normal. Brain CT findings were unremarkable expect for narrow right carotid canal (Fig. 1). The inferior part of the carotid canal was divided by a bony septum into two smaller canals. CT angiography revealed hypoplastic cervical segment of the right ICA and multiple vessels in the petrous canal, and parasellar area converging to the intradural paraclinoid segment of the ICA (Fig. 2). Digital subtraction angiography (DSA) was performed. Right carotid angiogram (Fig. 3a, b) demonstrated small caliber of ICA, including the first (cervical) and second (ascending petrous) segment. Distally, four tortuous vessels with a diameter of 1–2 mm were found along the course of the third (horizontal intrapetrous), fourth (ascending intrapetrous and in foramen lacerum) and fifth (horizontal segment of the carotid siphon) segments. These vessels converged to the sixth (clinoid) segment. The seventh (supraclinoid) segment of ICA and medial cerebral artery were normal. There was hypoplasia of the A1 segment of the anterior cerebral artery. Selective right external carotid artery showed no abnormalities. Angiograms of the left carotid and both vertebral arteries were normal. Our case describes developmental abnormalities of the petrous and cavernous portion of the ICA, consisted of four channel fenestrations associated with two small carotid canals. Fenestration or segmental duplication of the petrous and the cavernous segment of the ICA is considered an extremely rare anatomic variant. To the best of our knowledge, this is the first report of long-segment multichannel fenestration involving petrous and cavernous segments of the ICA. There is only one case of multichannel fenestrations of the petrous segment of the ICA reported by Mangla and Teitelbaum [2]. They described the shortsegment division of the petrous segment into four channels on DSA. The fenestration was approximately 1-cm long. Uchino et al. [3] have published the only case of intracavernous fenestration diagnosed by MR angiography and DSA. They described duplicate arterial lumens just proximal to the supraclinoid segment. Fenestrations in the supraclinoid and cervical segments are more common. D. Stojanov P. Bosnjakovic D. Benedeto-Stojanov S. Petrovic Faculty of Medicine, University of Nis, Nis, Serbia

Magnetization spoiling in radial FLASH contrast‐enhanced MR digital subtraction angiography

To increase the in-plane spatial resolution and image update rates of 2D magnetic resonance (MR) digital subtraction angiography (DSA) pulse sequences to 0.57 × 0.57 mm and 6 frames/sec, respectively, for intracranial vascular disease applications by developing a radial FLASH protocol and to characterize a new artifact, not previously described in the literature, which arises in the presence of such pulse sequences. The pulse sequence was optimized and artifacts were characterized using simulation and phantom studies. With Institutional Review Board (IRB) approval, the pulse sequence was used to acquire time-resolved images from healthy human volunteers and patients with x-ray DSA-confirmed intracranial vascular disease. Artifacts were shown to derive from inhomogeneous spoiling due to the nature of radial waveforms. Gradient spoiling strategies were proposed to eliminate the observed artifact by balancing gradient moments across TR intervals. The resulting radial 2D MR DSA sequence (2.6 sec temporal footprint, 6 frames/sec with sliding window factor 16, 0.57 × 0.57 mm in-plane) demonstrated small vessel detail and corroborated x-ray DSA findings in intracranial vascular imaging studies. Appropriate gradient spoiling in radial 2D MR DSA pulse sequences improves intracranial vascular depiction by eliminating circular banding artifacts. The proposed pulse sequence may provide a useful addition to clinically applied 2D MR DSA scans.

Validation of hyperintense middle cerebral artery sign in acute ischemic stroke: Comparison between magnetic resonance imaging and angiography.

We performed a retrospective analysis of non-contrast computed tomography (CT) scans, immediately subsequent magnetic resonance imaging (MRI), and cerebral angiography data from 30 consecutive patients with acute ischemic stroke within 6 hours after symptom onset. Results showed that eleven patients developed subsequent hemorrhagic transformation at follow-up. A hyperintense middle cerebral artery sign on MRI was found in six hemorrhagic patients, all of who had acute thrombosis formation on magnetic resonance angiography and digital subtraction angiography. No patients in the non-hemorrhagic group had hyperintense middle cerebral artery sign on MRI. The sensitivity, specificity, and positive predictive values of the hyperintense middle cerebral artery sign on MRI T1-weighted image for subsequent hemorrhagic transformation were 54.5%, 100%, and 100% respectively. Hyperdense middle cerebral artery sign on non-contrast CT was observed in nine patients, five of who developed hemorrhagic transformation. These data suggest that hyperintense middle cerebral artery sign on MRI T1-weighted image is a highly specific and moderately sensitive indicator of subsequent hemorrhagic transformation in patients after acute ischemic stroke, and its specificity is superior to CT.

Our Experience with Carotid Body Paragangliomas

Carotid body paragangliomas (CBP) are rare neoplasms arising from the small chemoreceptor organ in the adventitia of the common carotid bifurcation. The aim of this study is to present the diagnostic process, performed treatment and obtained results in patients with carotid body paragangliomas of the Department of Otolaryngology of Istanbul Education and Research Hospital between March 1997 and November 2008. Retrospective analysis was carried out, based on the medical documentation of 5 patients with carotid body paragangliomas (3 women and 2 men), age range 44 to 68 years with a mean of 59.6 years. Four of the patients were diagnosed and treated with Shamblin type II tumor, one of the patients with type I. Physical examination, radiological evaluation, method of the treatment and post-treatment complications were studied. The most common and single symptom was nonspecific neck mass. Preoperative diagnostic evaluation consisted of a color duplex ultrasonography, computerized tomography with contrast enhancement, magnetic resonance imaging and digital subtraction angiography. In all patients with Shamblin type I and II, blunt dissection of the tumor was conducted smoothly in the subadventitial plane. Postoperative vagus nerve and hypoglossal nerve deficit were reported in one case. Carotid body paraganglioma excision has higher risk of cranial nerve paresis and carotid artery injury, so it requires careful handling and good surgical skills to ensure complete removal.

Posterior-draining dural carotid cavernous fistulae: a possible cause of computed tomographic angiography negative isolated third nerve palsy.

Computed tomographic angiography (CTA) is a well-established non-invasive investigation for this neurological presentation to exclude intracranial aneurysms. However, dural arteriovenous fistulae with anterograde venous drainage only can be missed by CTA. Here we reported two patients with painful complete third nerve palsy and dural carotid cavernous fistulae with anterograde venous drainage only missed by CTA. The natural history and management option are discussed. In patients with persistent symptoms or without vasculopathic risk factors, magnetic resonance angiography (MRA) or digital subtraction angiography (DSA) should be considered to exclude the diagnosis.

Utility of time-resolved three-dimensional magnetic resonance digital subtraction angiography without contrast material for assessment of intracranial dural arterio-venous fistula

Intracranial dural arteriovenous fistula (DAVF) is an arteriovenous shunting disease of the dura. Magnetic resonance angiography (MRA) is expected to be a safer alternative method in evaluation of DAVF, compared with invasive intra-arterial digital subtraction angiography (IADSA). To evaluate the diagnostic use of time-spatial labeling inversion pulse (Time-SLIP) three-dimensional (3D) magnetic resonance digital subtraction angiography (MRDSA) without contrast material in six patients with DAVF. Images for 3D time-of-flight MRA, which has been a valuable tool for the diagnosis of DAVF but provide little or less hemodynamic information, and Time-SLIP 3D MRDSA, were acquired for each patient. The presence, side, and grade of the disease were evaluated according to IADSA. In all patients, the presence and side of the DAVF were correctly identified by both 3D time-of-flight MRA and Time-SLIP 3D MRDSA. Cortical reflux present in a patient with a grade 2b DAVF was not detected by Time-SLIP 3D MRDSA, when compared with IADSA findings. Time-SLIP 3D MRDSA provides hemodynamic information without contrast material and is a useful complementary tool for diagnosis of DAVF.

Managements of vagal paragangliomas: a report of 11 cases

To study the clinical characters, diagnosis, surgical outcomes and treatment strategies of vagal paraganglioma (VP). A retrospective review was performed on 11 patients with VP confirmed by surgery and pathology between January 2000 and July 2010. Although the combined application of ultrasonography, enhanced computed tomography (CT), magnetic resonance imaging (MRI) and digital subtraction angiography (DSA), the preoperative diagnostic accuracy rate was only 27.2%. All patients were managed by surgical resection (one malignant case with postoperative radiotherapy). All patients either had or developed a vagal palsy and additional cranial nerve or sympathetic nerve deficits were sustained in 8 patients after operation. With a median follow-up time of 41 months (range: 4 - 132 months), one case lost and the others survived without local recurrence or distant metastasis. VP are rare and liable to misdiagnose. For increasing the preoperative diagnosis rate of VP, the combined application of imaging tests is important and clinicians and radiologists should also enhance the awareness of this disease. Postoperative complications including nerve injury are inevitable and individual treatment is required.

Evaluation of Peripheral Arterial Disease with Nonenhanced Quiescent-Interval Single-Shot MR Angiography

To assess the diagnostic performance of quiescent-interval single-shot (QISS) magnetic resonance (MR) angiography, a nonenhanced two-dimensional electrocardiographically gated single-shot balanced steady-state free precession examination for the evaluation of symptomatic chronic lower limb ischemia. For this prospective institutional review board-approved, HIPAA-compliant study, the institutional review board waived the requirement for informed patient consent. The QISS nonenhanced MR angiography technique was evaluated in a two-center trial involving 53 patients referred for lower extremity MR angiography for suspected or known chronic peripheral arterial disease (PAD), with contrast material-enhanced MR angiography serving as the noninvasive reference standard. The accuracy of stenosis assessments performed with the nonenhanced MR angiography sequence was evaluated relative to the reference standard. Per-segment, per-region, and per-limb sensitivities and specificities were calculated, and assessments were considered correct only if they were in exact agreement with the reference standard-derived assessments. Generalized estimating equation (GEE) modeling with use of an unstructured binomial logit analysis was used to account for clustering of multiple measurements per case. The sensitivity and specificity of QISS MR angiography for the determination of nonsignificant (<50%) versus significant (50%-100%) stenosis were compared with the sensitivity and specificity of the reference standard. The diagnostic performance of nonenhanced MR angiography was found to be nearly equivalent to the diagnostic performances of contrast-enhanced MR angiography and digital subtraction angiography. Non-GEE segment-based analysis revealed that for the two reviewers, nonenhanced MR angiography had sensitivities of 89.7% (436 of 486 segments) and 87.0% (423 of 486 segments) and specificities of 96.5% (994 of 1030 segments) and 94.6% (973 of 1028 segments). QISS nonenhanced MR angiography offers an alternative to currently used imaging tests for symptomatic chronic lower limb ischemia, for which the administration of iodinated or gadolinium-based contrast agents is contraindicated.

Unenhanced ECG-gated fast spin-echo MR digital subtraction angiography (MRDSA) using short echo-spacing three-dimensional sequence of femoral arteries: Initial experience

To compare the image qualities of unenhanced electrocardiographically (ECG)-gated fast spin-echo magnetic resonance digital subtraction angiography (MRDSA) using a short echo-spacing three-dimensional (3D) sequence, known as sampling perfection with application-optimized contrasts using different flip angle evolutions (SPACE), and the conventional half-Fourier single-shot turbo spin-echo (HASTE) sequence. Unenhanced ECG-gated MRDSA using SPACE and HASTE of the femoral arteries were prospectively acquired in 13 healthy volunteers at 1.5 Tesla (T) MRI. Sequential frontal maximum-intensity-projection images produced by subtracting each of 10 systolic images from a diastolic image were evaluated quantitatively using paired t-test and qualitatively by two blinded radiologists using the Mann-Whitney U-test. Quantitatively, relative contrast against the background, contour sharpness index, and slope of the sequential signal changes of the superficial femoral artery of MRDSA using SPACE were significantly better than those of HASTE (P = 0.005, P = 0.001, and P < 0.0001, respectively). Qualitatively, the overall subjective image quality and sequential appearance changes of MRDSA using SPACE were significantly better than those of HASTE (P < 0.0001 and P < 0.0001, respectively). Unenhanced ECG-gated fast spin-echo MRDSA using SPACE produces increments in signal intensity, which reflect arterial pulse wave transmission, more clearly than the conventional HASTE sequence.

ECG-Triggered Non-Contrast-Enhanced MR Angiography (TRANCE) versus Digital Subtraction Angiography (DSA) in patients with peripheral arterial occlusive disease of the lower extremities

To prospectively determine the diagnostic value of electrocardiography-triggered non-contrast-enhanced magnetic resonance angiography (TRANCE) of the lower extremities including the feet versus DSA. All 43 patients with symptomatic peripheral arterial occlusive disease (PAOD) underwent TRANCE before DSA. Quality of MRA vessel depiction was rated by two independent radiologists on a 3-point scale. Arterial segments were graded for stenoses using a 4-point scale (grade 1: no stenosis; grade 2: moderate stenosis; grade 3: severe stenosis; grade 4: occlusion). Findings were compared with those of DSA. In the 731 vessel segments analysed, intra-arterial DSA revealed 283 stenoses: 33.6% moderate, 16.6% severe and 49.8% occlusions. TRANCE yielded a mean sensitivity, specificity, positive and negative predictive value and diagnostic accuracy to detect severe stenoses or occlusions of 95.6%, 97.4%, 87.2%, 99.2%, 97.1% for the thigh segments and 95.2%, 87.5%, 83.2%, 96.6%, 90.5% for the calf segments. Excellent overall image quality was observed for TRANCE in 91.4% versus 95.7% (DSA) for the thigh and in 60.7% versus 91.0% for the calves, while diagnostic quality of the pedal arteries was rated as insufficient. TRANCE achieves high diagnostic accuracy in the thigh and calf regions, whereas the pedal arteries showed limited quality.

Endovaskuläre Therapieoptionen der aneurysmatischen Subarachnoidalblutung

Aneurysmal subarachnoid hemorrhaging (ASH) is a severe condition with an acute symptomatic, often with a difficult course and accompanied by many complications. Aneurysms can be detected using computed tomography (CT), magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). Possible therapy options for ASH are surgical clipping and endovascular treatment using platinum coils. The surgical approach is an effective and safe method for avoiding recurrent bleeding.So-called Guglielmi detachable coils, with which aneurysms can be successfully embolized, have been available since 1991. Initially only a few different sizes of platinum coils were available but now complex forms of platinum coils with different lengths and rigidness are available so that many forms of aneurysm can be treated. Broad-based aneurysms, which could previously only be treated by surgery, can now be treated by the so-called balloon remodeling technique or stent-assisted coiling, whereby a balloon or stent is placed in the parent vessel to act as a scaffold for the coil. The results of the ISAT study demonstrated that a better outcome for patients could be achieved by endovascular treatment of aneurysms than by neurosurgical clipping of ruptured aneurysms. For this reason the first option should be endovascular treatment when possible. Asymptomatic aneurysms are being observed increasingly more often and primary treatment should be endovascular when possible. The somewhat higher re-bleeding rate for endovascular treatment could not diminish the better results of the ISAT study even during the 5-year follow-up.