Digital Subtraction Angiography For Detection Research Articles

Comparison of 3D-Computed Tomographic Angiography with Digital Subtraction Angiography for Detection of aneurysms among Spontaneous Subarachnoid Haemorrhagic Patients

Background: Detection of aneurysms among spontaneous subarachnoid haemorrhagic patients is a crucial issue for management.
 Objectives: The purpose of the present study was to compare the findings of 3D-computed tomographic angiography with digital subtraction angiography for detection of aneurysms among spontaneous subarachnoid haemorrhagic patients.
 Methodology: This comparative cross-sectional study was carried out in the Department of Neurosurgery and Cath Lab of Dhaka Medical College Hospital (DMCH), Dhaka, Bangladesh in collaboration with private diagnostic centre from September 2013 to February 2015 for a period of six (06) months. Adult patients diagnosed as a case of spontaneous SAH based on clinical features and confirmed by plain CT evidence of subarachnoid blood were included as study cases. Then both CTA and DSA were done in order to detect the cause of bleeding and make a treatment planning. All spiral CTAs were performed on a helical CT-Scan. Four vessels DSA were performed via a femoral approach in DMCH Cath Lab.
 Result: A total number of 37 patients presented with spontaneous subarachnoid haemorrhage were recruited for this study. CT Angiogram revealed aneurysm in 30(81.08%) patients. AVM found in 02(05.41%) patients and in 5(13.51%) patients CTA was negative for any abnormality. DSA of 37 patients revealed aneurysm in 32(86.49%) patients, AVM in 02(05.41%) patients and negative findings in 03(8.11%) patients. In CT Angiogram 25(67.57%) patients had single aneurysm. In DSA, 27(72.97%) patients had single aneurysm. The mean of the size of the aneurysms in CTA and DSA were in 6.70±3.04 mm and 6.75±2.94 mm (p>0.05). The mean of the neck width of the aneurysms in CTA and DSA were 3.86±2.06 mm and 3.41±1.67 mm (p>0.05). All aneurysm detected in CTA were also revealed in DSA.
 Conclusion: In conclusion the size, neck width and the location of aneurysm are detected in CTA and DSA equally without any statistical significant difference.
 Journal of National Institute of Neurosciences Bangladesh, July 2022;8(2):121-125

In Reply: Commentary: Value of 3-Dimensional Digital Subtraction Angiography for Detection and Classification of Intracranial Aneurysm Remnants After Clipping.

In Reply: Commentary: Value of 3-Dimensional Digital Subtraction Angiography for Detection and Classification of Intracranial Aneurysm Remnants After Clipping.

Value of 3-Dimensional Digital Subtraction Angiography for Detection and Classification of Intracranial Aneurysm Remnants After Clipping.

BACKGROUNDThe current gold standard for evaluation of the surgical result after intracranial aneurysm (IA) clipping is two-dimensional (2D) digital subtraction angiography (DSA). While there is growing evidence that postoperative 3D-DSA is superior to 2D-DSA, there is a lack of data on intraoperative comparison.OBJECTIVETo compare the diagnostic yield of detection of IA remnants in intra- and postoperative 3D-DSA, categorize the remnants based on 3D-DSA findings, and examine associations between missed 2D-DSA remnants and IA characteristics.METHODSWe evaluated 232 clipped IAs that were examined with intraoperative or postoperative 3D-DSA. Variables analyzed included patient demographics, IA and remnant distinguishing characteristics, and 2D- and 3D-DSA findings. Maximal IA remnant size detected by 3D-DSA was measured using a 3-point scale of 2-mm increments.RESULTSAlthough 3D-DSA detected all clipped IA remnants, 2D-DSA missed 30.4% (7 of 23) and 38.9% (14 of 36) clipped IA remnants in intraoperative and postoperative imaging, respectively (95% CI: 30 [ 12, 49] %; P-value .023 and 39 [23, 55] %; P-value = <.001), and more often missed grade 1 (< 2 mm) clipped remnants (odds ratio [95% CI]: 4.3 [1.6, 12.7], P-value .005).CONCLUSIONCompared with 2D-DSA, 3D-DSA achieves a better diagnostic yield in the evaluation of clipped IA. Our proposed method to grade 3D-DSA remnants proved to be simple and practical. Especially small IA remnants have a high risk to be missed in 2D-DSA. We advocate routine use of either intraoperative or postoperative 3D-DSA as a baseline for lifelong follow-up of clipped IA.

The value of three-dimensional digital subtraction angiography for detection and classification of intracranial aneurysm remnants after clipping

The value of three-dimensional digital subtraction angiography for detection and classification of intracranial aneurysm remnants after clipping

Virtual reality adds value to analysis of aneurysms post-flow diversion, coiling, and clipping

Purpose: The purpose of this study was to measure sensitivity of virtual reality (VR) in detecting biomarkers of neurovascular remodeling suboptimally evaluated in digital subtraction angiography (DSA) of treated unruptured, intracranial aneurysms. Methods: The sensitivity of virtual reality and digital subtraction angiography in detection of neurovascular biomarkers in aneurysms treated with flow diversion, coiling, and clipping were evaluated. Validated grading scales were integrated into a standardized rating platform. The respective novel and conceptual measures of minimal imaging important difference (MIID) and number needed to image (NNI) were calculated for each biomarker. Results: In flow diversion, coiling, and clipping, minimal imaging important difference and number needed to image were associated with virtual reality in detection of abnormal biomarkers, with the exception of stasis phase associated with digital subtraction angiography. Number needed to image was associated with flow diversion stent stenosis (RR: 7.00, 95% CI 0.37 to 131.97; OR: 7.46, 95% CI 0.38 to 148.49). Minimal imaging important difference was greatest in residual aneurysm filling (25%±66, 95% CI) in flow diversion and Meyer score in coiling (42.5%±17.69, 95% CI) and clipping (22.2%±13.58, 95% CI). Regression models demonstrated minimal imaging important difference and number needed to image shared a significant correlation (R20.99, 95% CI, p&lt;0.001). Conclusion: Virtual reality adds value to digital subtraction angiography in evaluation of aneurysms treated with flow diversion, coiling, and clipping. Larger, prospective studies are warranted to increase statistical power and validate clinical significance.

Role of digital subtraction angiography in detection of intracranial aneurysms compared with computed tomographic angiography

Objective To evaluate the role of digital subtraction angiography (DSA) in the detection of intracranial aneurysms among patients with spontaneous subarachnoid hemorrhage (SAH) compared with computed tomographic angiography (CTA) in a single center, Sri Lanka. Methods A total of 123 patients clinically and CT proven SAH were evaluated with CT angiography and DSA with a median interval of 3 days. The sensitivity, specificity and accuracy of CT angiography in detecting aneurysms were analyzed compared to DSA on a per-patient, per-size, per-site and per morphological basis. All data were analyzed using SPSS analytical package (version 18). Ethical approval for the study was from the institutional ethical review board. Results Among 123 patients with clinically and CT proven SAH, 51 (41.5%) patients showed aneurysms on CT angiography. 72 were negative for aneurysms in CTA. In 13 out of 72 (18%) CTA negative patients subsequent DSA demonstrated aneurysms. Number of CTA negative but DSA positive aneurysm were 15 as two of the patients had two aneurysms each. Four CTA detected aneurysms could not be appreciated in the subsequent DSAs. Aneurysms (47)detected by both CT angiography and DSA were more than 6mm in size (56.7%) , sacculartype (96.5%) and were located in the anterior circulation system (92.4%). Most CTA negative aneurysms detected by DSA were less than 6mm in size (80%), saccular type (60%) and were located in anterior (53.8%) and posterior (46.7%) circulation system. The sensitivity, specificity, positive predictive value and negative predictive value of CT angiography compared to DSA per patient basis were 78.3%, 93.7%, 92.2% and 81.9% respectively. CT angiography has a low sensitivity to detect aneurysms less than 6mm size (65.7%%), in posterior circulation (36.4%) and other morphological types (0%) compared to aneurysms more than 6mm size (90.9%), in anterior circulation (85.9%) and saccular type (85.5%). Conclusion Digital subtraction angiography (DSA) has a significant role in detecting intracranial aneurysms which are less than 6mm in size, are located in posterior circulation system and of non-saccular morphological type.

Diagnostic accuracy of computed tomography angiography in detection of post traumatic renal vascular injury

ObjectivesTo evaluate accuracy of computed tomography angiography (CTA) in evaluation of post traumatic renal vascular injury. Patients and methods38 patients were presented with post traumatic intermittent or persistent hematuria. Renal CTA and digital subtraction angiography (DSA) were done for all patients. ResultsCTA demonstrated pseudoaneurysm (PA) in 30 patients (78.9%) and no vascular lesions in 8 patient (21.1%). CTA had 86.11% sensitivity and 50% specificity in detection of post traumatic renal pseudoaneurysms, CTA missed diagnosis of renal arteriovenous fistula (RAVF) in 10 patients which discovered later by DSA. ConclusionCTA with MIP as non invasive technique widely replaced renal DSA in detection of posttraumatic renal pseudoaneurysm. Renal DSA is still best modality in detection of RAVF and also has the upper hand in planning of selective renal artery embolization for the management of persistent or delayed hemorrhage from renal vessels.

Perimesencephalic Hemorrhage: Yield of Single versus Multiple DSA Examinations-A Single-Center Study and Meta-Analysis.

Purpose To quantify the rate of detection of aneurysms at follow-up digital subtraction angiography (DSA) after initial DSA with results negative for aneurysms in subjects with perimesencephalic (PM) nonaneurysmal subarachnoid hemorrhage. Materials and Methods This single-center retrospective study and meta-analysis was approved by the institutional review board. At a single institution from 2000 to 2013, 252 consecutive patients with subarachnoid hemorrhage at computed tomography (CT) and two DSA examinations negative for aneurysm within 10 days were evaluated for inclusion in the study, and 131 met CT criteria for PM nonaneurysmal subarachnoid hemorrhage (53 women; mean age, 53 years [range, 33-88 years]). DS angiographic reports were reviewed for causative abnormalities. Three reviewers searched MEDLINE and electronic databases for studies that reported detection of aneurysm in subjects with PM hemorrhage who had undergone multiple DSA examinations. Main inclusion criteria were PM hemorrhage at CT per van Gijn classification, head CT performed within 72 hours of symptom onset, initial DS angiographic results negative for aneurysm, and two DSA examinations within 10 days. Studies with fewer than 25 subjects were excluded. Methodology was assessed by using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The summary rate of aneurysm detection for subsequent DSA was calculated by using a fixed-effects model. Results Six studies with 298 subjects and a single-institution study with 131 subjects were included. No aneurysms were seen at follow-up DSA in the single-center study (0.0%). Three aneurysms were detected at follow-up DSA in three of six studies from the literature (one of 29 [3.4%], one of 65 [1.5%], and one of 34 [2.9%] patients). Two occurred in cases that likely preceded the use of the current DSA technique. The summary aneurysm detection rate at subsequent DSA was 1.6% (95% confidence interval: 0.7%, 3.8%; range of individual study detection rate: 0.0%-3.4%). Conclusion In patients with PM nonaneurysmal subarachnoid hemorrhage and initial DSA negative for aneurysms, the yield of follow-up DSA for detection of causative aneurysms is very low. © RSNA, 2016 Online supplemental material is available for this article.

Diagnostic yield and accuracy of CT angiography, MR angiography, and digital subtraction angiography for detection of macrovascular causes of intracerebral haemorrhage: prospective, multicentre cohort study

Study question What are the diagnostic yield and accuracy of early computed tomography (CT) angiography followed by magnetic resonance imaging/angiography (MRI/MRA) and digital subtraction angiography (DSA) in patients with non-traumatic...

Digital Subtraction Angiography Versus RealTime Fluoroscopy for Detection of Intravascular Penetration Prior to Epidural Steroid Injections: Meta-Analysis of Prospective Studies

Background: Neurological injury is a rare but devastating complication of epidural steroid injections (ESIs) generally thought to arise from neurovascular compromise. The use of real-time fluoroscopy (RTF) with contrast media is the most common preventative measure taken to avoid intravascular penetration. In 2002, it was proposed that digital subtraction angiography (DSA) might be more useful than RTF. Since then, several prospective studies have advocated for its use. Objectives: As DSA is not currently a “gold standard,” a meta-analysis was performed to compare the efficacy of DSA versus RTF for detection of intravascular penetration during ESI. Study Design: Meta-analysis of prospective observational studies. Methods: A targeted Pubmed search was conducted, yielding 49 reports and 4 manuscripts, which were analyzed using Review Manager Software (Rev Man 5.2). Inclusion/exclusion criteria: peer-reviewed prospective reports comparing the sensitivity of DSA to RTF in the same individuals without change in needle position between comparative imaging. Pooled estimate of odds ratios with 95% confidence interval using a random effect model was applied. Results: There were a total of 188 intravascular events from 1,290 ESIs performed. RTF was able to detect 148 events with DSA detecting an additional 40 events missed by RTF. No major neurological complications were reported. DSA had a statistically significant favorable odds ratio over RTF for detection of intravascular penetration during ESI (OR = 1.32 [1.05 – 1.67]; P = 0.02). Limitations: Although the major methodological aspects of each study assessed in this metaanalysis were quite similar, there were small differences in needle gauge and the selection of secondary outcome measures. Despite attempts to minimize it, concern for operator bias also exists. Conclusions: DSA had a 32% improvement (OR = 1.32) for detection of intravascular penetration with ESI when compared to RTF. Although this supports advocacy for use of DSA, it also suggests that there is a greater than 30% “missed-events” rate for detection of vascular penetration when using RTF for ESI, which does not correlate with the generally reported cumulative rates of complications (1%). This discrepancy suggests that factors other than vascular events also play a role in complications. Nonetheless, given the evidence, we advocate for the increased use of DSA over RTF for transformational ESIs. Key words: Digital subtraction angiography, real-time fluoroscopy, epidural steroid injection, complications, outcomes, pain imaging, chronic pain, intravascular injection, meta-analysis

A comparative study of computed Tomographic Angiography and digital subtraction Angiography in evaluation of Aneurysmal Subarachnoid Haemorrhage

Context: The aim of the study was to retrospectively analyze the performance of Computed Tomographic Angiography (CTA) in detecting, localizing and sizing intracranial aneurysms in patients of aneurysmal subarachnoid haemorrhage using Digital Subtraction Angiography (DSA) as standard. Methods: The study was carried out from December 2009 to November 2010 in the Dept. of Neurology of Dhaka Medical College Hospital, Dhaka. Among 81 patients of SAH admitted in the above mentioned period, 30 were enrolled in the study as they met the inclusion criteria. Patient’s age range was 26 to 70 years; male female ratio was 1.5: 1. All the study patients underwent both DSA and CTA examinations. The findings of both procedures were recorded and compared. Results: A total of 30 aneurysms in 30 patients were identified on DSA. Among 10 small sized aneurysms (&lt;4 mm) detected by DSA, CTA incorrectly diagnosed 2 and overlooked 2 aneurysms. Out of 14 medium sized (5- 12 mm) identified on DSA, CTA missed 2 aneurysms. But CTA correctly diagnosed all 6 large (e”13 mm) aneurysms. The overall sensitivity of CTA was 60% for small, 85.7% for medium and 100% for large aneurysm. Regarding identification of aneurysmal sites, CTA correctly localized 22 (73.4%), incorrectly localized 4 (13.3%) and missed 4 (13.3%) cases. Sensitivity of CTA in identification of aneurysmal site was 73.3%. Conclusion: CTA is less sensitive than DSA in detecting small and medium sized aneurysms. However it correlated perfectly with DSA in detection of large aneurysms. The performance of CTA in identification of aneurysmal site is also lesser than DSA. So, DSA remains the standard technique for evaluation of aneurysmal SAH. DOI: http://dx.doi.org/10.3329/jdmc.v22i2.21542 J Dhaka Medical College, Vol. 22, No.2, October, 2013, Page 195-200

Comparison of 64 Dedector Cranial CT Angiography with Intra-Arterial DSA For Detection of Intracranial Aneurysms

The purpose of our study was to compare findings of 64 detector cranial computed tomographic angiography (CTA) and convention al digital subtraction angiography (DSA) mainly in patients with acute subarachnoid hemorrhage (SAH) headache and diplopia. Between March 2007 and May 2009, 65 consecutive patients were admitted with clinical symptoms and signs of intracranial aneurysm. 44 of 67 detected aneurysms were confirmed during surgery or endovascular embolization. DSA was performed in the 3 days after CTA. CT angiograms and conventional angiographies were studied by two radiologists, who performed aneurysm detection and characterisation of morphological features. Using CTA and DSA, we detected 67 aneurysms in 50 patients. 15 patients did not have any aneurysms in both DSA and CTA. There was no difference between the two modalities in the number of the detected aneurysms. But two aneurysms were falsely located before surgery with CTA. They were located in posterior communicating artery (PcoA) but, had been thought to be located at the internal carotid artery supraclinoid segment at CTA. CTA has an equal sensitivity as DSA in the detection of intracranial aneurysms. It has 100% detection rate in anterior communicating artery and middle cerebral artery bifurcation aneurysms, but aneurysms at some locations, like the ones at PcoA, were hard to detect with CTA. DSA preserves its diagnostic value for detection of posterior circulation aneurysms.

Comparison of high-resolution MRI with CT angiography and digital subtraction angiography for the evaluation of middle cerebral artery atherosclerotic steno-occlusive disease

Intracranial atherosclerotic disease is increasingly recognized as a major stroke subtype worldwide. Current diagnostic evaluation of atherosclerotic disease of the middle cerebral artery (MCA) relies on detection of stenoses with luminographic imaging studies that do not directly visualize plaque unlike high-resolution MRI. This retrospective study seeks to evaluate the accuracy of high-resolution MRI vessel wall imaging, computed tomographic angiography (CTA) and digital subtraction angiography (DSA) in measuring the degree of stenosis within the MCA. 28 recently symptomatic patients with MCA territory symptoms underwent preliminary imaging with CTA followed by high-resolution MRI at 3-Tesla and definitive imaging with DSA for detection of M1 territory steno-occlusive lesions. Measurements of MCA segments on MRI and CTA were compared with reference to DSA values. Sensitivity and specificity of high-resolution MRI vessel wall imaging, CTA using maximum intensity projection (MIP) and CTA using volume rendering (VR) for the detection of stenosis > 50 % and occlusion were 80.0 and 53.6 %, 72.2 and 72.7 %, and 77.8 and 18.2 %, respectively. MRI-derived values correlated better with DSA (Spearman R = 0.68, p < 0.01) than CTA MIP and VR (Spearman R = 0.45, 0.22; p = 0.02, 0.24, respectively). High-resolution MRI of the MCA is capable of accurately measuring the degree of stenosis and is more sensitive than CTA in a sample of high-risk, symptomatic patients. This study, combined with previous reports, supports the potential of morphological MRI to measure intracranial atherosclerotic plaque non-invasively.

Diagnostic Accuracy of Computed Tomographic Angiography for Blunt Cerebrovascular Injury Detection in Trauma Patients

To compare the diagnostic accuracy of computed tomographic angiography (CTA) with digital subtraction angiography (DSA) for blunt cerebrovascular injury (BCVI) detection in trauma patients. Controversy exists as to whether the diagnostic performance of CTA compares favorably with the reference-standard, DSA. We searched electronic databases (1950 to May 22, 2012), article bibliographies, conference proceedings (2008-2011), and clinical trial registries for studies comparing the accuracy of CTA with DSA for BCVI detection in trauma patients. Pooled estimates of sensitivity, specificity, and positive and negative likelihood ratios were calculated using bivariate random effects models. Eight studies that examined 5704 carotid or vertebral arteries in 1426 trauma patients met inclusion criteria. The pooled sensitivity and specificity for BCVI detection with CTA versus DSA was 66% (95% CI, 49%-79%; I = 80.4%) and 97% (95% CI, 91%-99%; I = 94.6%), respectively. Corresponding pooled positive and negative likelihood ratios were 20.0 (95% CI, 6.9-58.4; I = 87.7%) and 0.35 (95% CI, 0.22-0.56; I = 74.9%), respectively. Although pooled sensitivity varied with the number of available CT slices, the training of interpreting radiologists, and in a pattern suggestive of differences in diagnostic threshold for judging CTA positivity, it remained 80% or less among studies that used scanners with 16 or more slices per rotation and where the CTA was read by neuroradiologists. Existing evidence suggests that the diagnostic performance of CTA varies considerably across studies, likely due to an implicit variation in diagnostic threshold across trauma centers. Moreover, although CTA appears to lack sensitivity to adequately rule out BCVI, it may be useful to rule in BCVI among trauma patients with a high pretest probability of injury.

How Accurate Is CT Angiography in Evaluating Intracranial Atherosclerotic Disease?

Digital subtraction angiography (DSA) is regarded as the gold standard in assessing degree of stenosis in intracranial vessels. However, it is invasive and can only be carried out at specialized centers. We sought to compare CT angiography (CTA) to DSA for detection and measurement of stenosis in large intracranial arteries. We identified all subjects admitted with ischemic stroke or transient ischemic attack and with CTA and DSA studies of good quality completed within 30 days of each other between April 2000 and May 2006 at a single medical center. Two readers blinded to clinical information reviewed each CTA and DSA independently. Each reader located and measured stenosis of 15 prespecified large intracranial arterial segments per study at the same level of magnification. These stenotic lesions were most likely atherosclerotic in etiology. All measurements were made with Wiha digiMax 6" digital calipers. The degree of stenosis was calculated using the published method for the Warfarin-Aspirin Symptomatic Intracranial Disease study. All disagreements of greater than 10% were reviewed by a third reader who decided between the 2 prior measurements. Segments were excluded from analyses if they were judged to be congenitally hypoplastic or seen only through collaterals or cross-filling. Intraclass correlation, sensitivity, and specificity were calculated using DSA as the reference standard. Forty-one pairs of CTA and DSAs from 41 patients were reviewed. CTAs were completed within 28 days before 13 days after DSA, with a median of 1 day. A total of 475 pairs of major intracranial arterial segment were analyzed. Intraclass correlation between degree of stenosis based on CTA and DSA for all segments was 0.98 (P=0.001). CTA detected large arterial occlusion with 100% sensitivity and specificity. For detection of >or=50% stenosis, CTA had 97.1% sensitivity and 99.5% specificity. To detect all lesions >or=50% as determined by DSA, the cut off point on CTA appeared to be at >or=30%, with a false-positive rate of 2.4%. Compared to DSA, CTA has high sensitivity and specificity for detecting >or=50% stenosis of large intracranial arterial segments. CTA is minimally invasive and may be a useful screening tool for intracranial arterial disease and occlusion.

Follow up of coiled intracranial aneurysms with standard resolution and higher resolution magnetic resonance angiography

Time-of-flight magnetic resonance angiography is a non-invasive alternative to digital subtraction angiography (DSA) for follow up of coiled intracranial aneurysms. Standard cranial MRA protocols are a compromise between spatial resolution and imaging time. This study compares a standard resolution MRA protocol with a protocol at higher spatial resolution MRA (HR-MRA) in 21 follow-up occasions in 17 coiled aneurysms in 15 patients. Images were reviewed for presence of residual or recurrent aneurysm and compared with DSA as the gold standard. Aneurysm flow signal on standard resolution MRA differed significantly from HR-MRA in 6/21 cases (P = 0.02) and DSA in 6/21 cases (P = 0.02). HR-MRA had 100% concordance with DSA (P = 1.0). In this study, three-dimensional time-of-flight magnetic resonance angiography carried out at standard resolution is inadequate for follow up of coiled intracranial aneurysms. HR-MRA is comparable to DSA for detection of aneurysm recurrence.

Supraaortic Arteries: Contrast-enhanced MR Angiography at 3.0 T—Highly Accelerated Parallel Acquisition for Improved Spatial Resolution over an Extended Field of View

To prospectively use 3.0-T breath-hold high-spatial-resolution contrast material-enhanced magnetic resonance (MR) angiography with highly accelerated parallel acquisition to image the supraaortic arteries of patients suspected of having arterial occlusive disease. Institutional review board approval and written informed consent were obtained for this HIPAA-compliant study. Eighty patients (44 men, 36 women; age range, 44-90 years) underwent contrast-enhanced MR angiography of the head and neck at 3.0 T with an eight-channel neurovascular array coil. By applying a generalized autocalibrating partially parallel acquisition algorithm with an acceleration factor of four, high-spatial-resolution (0.7 x 0.7 x 0.9 mm = 0.44-mm(3) voxels) three-dimensional contrast-enhanced MR angiography was performed during a 20-second breath hold. Two neuroradiologists evaluated vascular image quality and arterial stenoses. Interobserver variability was tested with the kappa coefficient. Quantitation of stenosis at MR angiography was compared with that at digital subtraction angiography (DSA) (n = 13) and computed tomographic (CT) angiography (n = 12) with Spearman rank correlation coefficient (R(s)). Arterial stenoses were detected with contrast-enhanced MR angiography in 208 (reader 1) and 218 (reader 2) segments, with excellent interobserver agreement (kappa = 0.80). There was a significant correlation between contrast-enhanced MR angiography and CT angiography (R(s) = 0.95, reader 1; R(s) = 0.87, reader 2) and between contrast-enhanced MR angiography and DSA (R(s) = 0.94, reader 1; R(s) = 0.92, reader 2) for the degree of stenosis. Sensitivity and specificity of contrast-enhanced MR angiography for detection of arterial stenoses greater than 50% were 94% and 98% for reader 1 and 100% and 98% for reader 2, with DSA as the standard of reference. Vascular image quality was sufficient for diagnosis or excellent for 97% of arterial segments evaluated. By using highly accelerated parallel acquisition, the described 3.0-T contrast-enhanced MR angiographic protocol enabled visualization and characterization of the majority of supraaortic arteries, with diagnostic or excellent image quality (97% of arterial segments) and diagnostic values comparable with those obtained by using CT angiography and DSA for detection of arterial stenoses.

Comparison of Intraarterial MR Angiography at 3.0 T with X-ray Digital Subtraction Angiography for Detection of Renal Artery Stenosis in Swine

To compare the accuracy of catheter-directed intraarterial (IA) magnetic resonance (MR) angiography at 3.0 T with that of x-ray digital subtraction angiography (DSA) for the measurement of renal artery stenosis (RAS) in swine. Unilateral hemodynamically significant RAS (>50%) was induced surgically in six pigs with use of reverse cable ties. One to two weeks after surgery, each pig underwent x-ray DSA and MR angiography before and after percutaneous transluminal balloon angioplasty (PTA). X-ray DSA was performed before and after PTA of RAS by injection of iodinated contrast agent through a 5-F multiple-side hole angiographic catheter placed in the abdominal aorta under fluoroscopic guidance. MR angiography of RAS was performed before and after PTA of RAS on a 3.0-T clinical MR imager with use of gadolinium-based contrast agent. MR angiography and DSA images were analyzed with the full width at half maximum method. Percent stenosis measurements between x-ray DSA and MR angiography were compared with a paired t test and were correlated with linear regression and Bland Altman analysis (alpha = 0.05). Six cases of RAS were induced and imaged successfully with DSA and MR angiography techniques before and after PTA. On x-ray DSA, median stenoses was 64% (95% CI 57%-80%) before PTA and 20% (95% CI 5%-32%) after PTA. Corresponding MR angiography median stenosis measurement was 69% (95% CI 58%-80%) before PTA and 26% (95% CI 16%-36%) after PTA. A paired t test comparison did not show a difference between DSA and MR angiography (P = .16). RAS measurements on MR angiography correlated closely (P < .01) with DSA measurements (r(2) = 0.92). In swine, the accuracy of catheter-directed IA MR angiography with use of a clinical 3.0-T MR imaging unit for the measurement of RAS was similar to that of conventional x-ray DSA.

Inflow Stenoses in Dysfunctional Hemodialysis Access Fistulae and Grafts

The aim of the study is to prospectively determine the incidence of inflow stenoses in dysfunctional hemodialysis access arteriovenous fistulae (AVFs) and grafts (AVGs). Contrast-enhanced magnetic resonance angiography (CE-MRA) was performed of 66 dysfunctional AVFs and 35 AVGs in 56 men and 45 women (mean age, 62 years; age range, 31 to 86 years). Complete inflow (from the subclavian artery), shunt region, and complete outflow (including subclavian vein) were shown at CE-MRA. In addition to standard digital subtraction angiography (DSA) of the shunt region and outflow, DSA of the complete inflow was obtained through access catheterization of all cases in which CE-MRA showed an inflow stenosis. Vascular stenosis is defined as greater than 50% decrease in luminal diameter compared with an uninvolved vascular segment located adjacent to the stenosis. Endovascular intervention of stenoses was performed in connection with DSA. CE-MRA showed 19 arterial stenoses in 14 patients (14%). DSA confirmed 18 of these lesions in 13 patients and showed no additional inflow lesions. Of the 13 patients, 7 patients had arterial stenoses only and 6 patients had accompanying stenoses in the shunt region and/or outflow. Referral criteria for the 13 patients to undergo access evaluation had been decreased flow rates (9 patients), steal symptoms (2 patients), and insufficient access maturation (2 patients). Access flow of the 9 patients with a low-flow access improved from 477 +/- 74 mL/min to 825 +/- 199 mL/min after angioplasty. One patient with steal symptoms became symptom free after angioplasty. Endovascular intervention in 3 patients proved to be unsuccessful. Inflow stenoses are not uncommon in dysfunctional hemodialysis access shunts. We suggest that radiological evaluation comprise assessment of the complete arterial inflow.

Comparison of computerized tomography angiography and digital subtraction angiography in ruptured cerebral aneurysm surgery

Objective: The aim of the present study was to review the efficacy of 16‐row multislice computerized tomography angiography (CTA) in ruptured cerebral aneurysm surgery by comparison with conventional digital subtraction angiography (DSA).Methods: A systemic review of patients suffering from ruptured cerebral aneurysm was performed. We report the results obtained during the 19‐month period from April 2003 to October 2004. In total, 32 patients had undergone aneurysm surgeries, in which 11 patients had both DSA and CTA performed.Results: Among the 11 patients with both DSA and CTA performed, two aneurysms were missed in DSA in two patients. The sensitivity and specificity of CTA were 100%. The correlation of CTA with DSA in operative findings was 100%. Our CTA could detect the aneurysm size down to 2 mm in diameter.Conclusion: The diagnostic accuracy of 16‐row multislice CTA is promising and it compares well with DSA for detection and evaluation of ruptured cerebral aneurysms. It is safe and effective to establish treatment decision on the basis of CTA alone in the majority of cases.