SEARCH · PubMed Health

Results for “Angiography, Digital Subtraction”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

PubMed2001

Surgical anatomy of the cerebral arteries in patients with subarachnoid hemorrhage: comparison of computerized tomography angiography and digital subtraction angiography.

OBJECT: The purpose of this study was to compare computerized tomography (CT) angiography and digital subtraction (DS) angiography studies in patients with subarachnoid hemorrhage (SAH) to assess their vascular anatomy relevant to cerebral aneurysm surgery. METHODS: From a prospective series of 100 patients with SAH, the authors selected 73 patients whose CT angiography studies were of adequate quality and in whom DS angiography of both carotid arteries had been performed. Eleven patients with no DS angiographic studies of the vertebrobasilar artery were only evaluated for the anterior half of the circle of Willis. Anterior communicating arteries (ACoAs), both precommunicating anterior cerebral arteries (A1 segments), both posterior communicating arteries (PCoAs), and both precommunicating posterior cerebral arteries (P1 segments) were assessed on CT angiography and DS angiography by two independent observers. CONCLUSIONS: Computerized tomography angiography compares well with DS angiography for visualizing normal-sized arteries, and is superior for visualizing ACoAs and hypoplastic A1 and P, segments. Important preoperative aspects such as dominant A1 segments and PCoAs are equally well seen using either modality. Neither method enabled the authors to visualize more than 50% of PCoAs. Use of CT angiography can provide the required preoperative anatomical information for aneurysm surgery in most patients with SAH.

Adult↗

PubMed2004

[Grading of carotid artery stenosis using high resolution dynamic magnetic resonance angiography in comparison to intraarterial digital subtraction angiography. Are stenoses over 70% reliably detectable?].

PURPOSES: Evaluation of high resolution dynamic magnetic resonance angiography (ceMRA) in detection and graduation of carotid artery stenosis in comparison to intraarterial digital subtraction angiography. MATERIALS AND METHODS: Magnetic resonance angiography and intraarterial digital subtraction angiography was performed in 65 patients with suspected carotid artery stenosis by ultrasound examination. Detection and graduation of carotid artery stenosis by magnetic resonance angiography were compared to those of intraarterial digital subtraction angiography after stenosis grading according to NASCET criteria. RESULTS: All magnetic resonance angiographies were of excellent quality, with 46 stenoses type I and II and 12 stenoses type III NASCET correctly identified and classified by magnetic resonance angiography. Overestimation was found in 4 cases and underestimation in 2 cases. Both modalities detected 13 occlusions. Sensitivity and specificity of ceMRA were 92%. The positive predictive value was 86% and the negative predictive value 96%. CONCLUSION: High resolution dynamic magnetic resonance angiography is suitable in detecting and classifying carotid artery stenoses over 70% with high sensitivity and specificity in comparison to intraarterial digital subtraction angiography. Intraarterial digital subtraction angiography should only be performed in critical cases.

Aged↗

PubMed2005

Stenosis detection in failing hemodialysis access fistulas and grafts: comparison of color Doppler ultrasonography, contrast-enhanced magnetic resonance angiography, and digital subtraction angiography.

OBJECTIVE: Several imaging modalities are available for the evaluation of dysfunctional hemodialysis shunts. Color Doppler ultrasonography (CDUS) and digital subtraction angiography (DSA) are most widely used for the detection of access stenoses, and contrast-enhanced magnetic resonance angiography (CE-MRA) of shunts has recently been introduced. To date, no study has compared the value of these three modalities for stenosis detection in dysfunctional shunts. We prospectively compared CDUS and CE-MRA with DSA for the detection of significant (> or = 50%) stenoses in failing dialysis accesses, and we determined whether the interventionalist would benefit from CDUS performed before DSA and endovascular intervention. METHODS: CDUS, CE-MRA, and DSA were performed of 49 dysfunctional hemodialysis arteriovenous fistulas and 32 grafts. The vascular tree of the accesses was divided into three to eight segments depending on the access type (arteriovenous fistula or arteriovenous graft) and the length of venous outflow. CDUS was performed and assessed by a vascular technician, whereas CE-MRA and DSA were interpreted by two magnetic resonance radiologists and two interventional radiologists, respectively. All readers were blinded to information from each other and from other studies. DSA was used as reference standard for stenosis detection. RESULTS: DSA detected 111 significant (> or = 50%) stenoses in 433 vascular segments. Sensitivity and specificity of CDUS for the detection of significant stenosed vessel segments were 91% (95% CI, 84%-95%) and 97% (95% CI, 94%-98%), respectively. We found a positive predictive value of 91% (95% CI, 84%-95%) and a negative predictive value of 97% (95% CI, 94%-98%). The sensitivity, specificity, positive predictive value, and negative predictive value of MRA were 96% (95% CI, 90%-98%), 98% (95% CI, 96%-99%), 94% (95% CI, 88%-97%), and 98% (95% CI, 96%-99%), respectively. CDUS and CE-MRA depicted respectively three and four significant stenoses in six nondiagnostic DSA segments. The interventionalist would have chosen an alternative cannulation site in 38% of patients if the CDUS results had been available. CONCLUSIONS: We suggest that CDUS be used as initial imaging modality of dysfunctional shunts, but complete access should be depicted at DSA and angioplasty to detect all significant stenoses eligible for intervention. CE-MRA should be considered only if DSA is inconclusive.

Adult↗

PubMed2004

Multidetector CT angiography versus digital subtraction angiography for aortoiliac length measurements prior to endovascular AAA repair.

PURPOSE: To assess observer variation between calibrated-catheter digital subtraction angiography (DSA) and software-enhanced multidetector computed tomography angiography (CTA) in measuring vessel length prior to endovascular aortic aneurysm repair (EVAR). METHODS: Thirty patients (25 men; mean age 65 years, range 61-85) scheduled for EVAR underwent CTA in 4x2-mm collimation using advanced vessel analysis software. CTA measurements were performed twice by 2 blinded readers in random order with at least a 4-week interval between readings. Nine patients were found unsuitable for endovascular repair after the CTA, so DSA was performed in 21 patients for morphometric evaluation of the abdominal aorta and the iliac arteries. The following segments were measured: H1 (aneurysm neck), H2 (lower renal artery to distal aspect of the aneurysm), H3 (lower renal artery to aortic bifurcation), and H4a/H4b (lower renal artery to iliac bifurcations). Length measurements on DSA were made by (1) following the catheter path in the aortic lumen and (2) dividing tortuous vessel anatomy into segments and measuring each segment along an idealized centerline. Addition of the various segments allowed comparison with data obtained from CTA measurements. RESULTS: CTA was performed with good intraobserver agreement for all length parameters except H3 in reader 2 (p<0.05). While good interobserver agreement was demonstrated for CTA over long aortoiliac distances (H4a, H4b), higher interobserver agreement was obtained with DSA for shorter segments (H1, H2). Considerable differences were observed between CTA and DSA for the lengths H2 and H4b. CONCLUSIONS: CTA produces better intra and interobserver correlations in measuring vessel length than DSA. It has the potential to replace DSA as an imaging method before EVAR.

Aged↗

PubMed2005

Multi-detector row CT angiography in the assessment of carotid artery disease in symptomatic patients: comparison with rotational angiography and digital subtraction angiography.

BACKGROUND AND PURPOSE: Compared with the single-detector technique, multi-detector row CT angiography permits larger anatomic coverage that includes both the epiaortic and entire carotid circulations. We evaluated the accuracy of multi-detector row CT angiography by using multiplanar reformation (MPR) for measuring carotid artery diameters compared with that of rotational angiography. We also evaluated the diagnostic performance of CT angiography compared with digital subtraction angiography (DSA). METHODS: In 35 patients, CT angiograms of 70 carotid arteries were compared with DSA images, and CT angiograms of 33 carotid arteries were compared with rotational angiograms. CT angiographic interpretation was performed first interactively at a workstation. Diameter measurements of normal and stenosed carotid arteries were performed on cross-sectional and oblique sagittal MPRs. Degree of stenosis was calculated per North American Symptomatic Carotid Endarterectomy Trial criteria independently by two observers for each technique. RESULTS: Degree of stenosis was slightly underestimated with CT angiography, with mean differences (+/- SD) per observer of 6.9 +/- 17.6% and 10.7 +/- 16.1% for cross-sectional and 2.8 +/- 19.2% and 9.1 +/- 16.8% for oblique sagittal MPRs compared with rotational angiography. CT angiography was somewhat inaccurate for measuring the absolute minimal diameter of high-grade stenoses. On symptomatic sides (n = 35), interactive CT angiographic interpretation combined with MPR measurements for lesions with a visual estimate of 50% or greater stenosis achieved a sensitivity of 95% (20/21) and specificity of 93% (13/14) in the detection of carotid stenosis (>/= 50%) verified with DSA. CONCLUSION: Regardless of slight underestimation of carotid stenosis with CT angiography compared with rotational angiography, diagnostic performance of CT angiography with interactive interpretation proved to be good. Also, the method is highly sensitive for detection of carotid artery stenosis, indicating the suitability of CT angiography as a screening method for symptomatic patients. For hemodynamically significant stenoses revealed by CT angiographic screening, conventional angiography still seems to be necessary.

Aged↗

PubMed2004

Comparison of contrast-enhanced magnetic resonance angiography and digital subtraction angiography in patients with chronic critical ischemia and tissue loss.

RATIONALE AND OBJECTIVES: To compare the ability of intra-arterial digital subtraction angiography (IA-DSA) and total runoff contrast-enhanced magnetic resonance angiography (CE-MRA) to demonstrate peripheral arterial anatomy, specifically in patients with chronic critical ischemia and tissue loss. MATERIALS AND METHODS: Twenty-three consecutive patients with chronic critical ischemia and tissue loss underwent CE-MRA and IA-DSA within 2 days. Two teams, consisting of an interventional radiologist and vascular surgeon who were blinded to each other's results, determined the number of named arteries (21 segments) and the presence of >/=50% stenosis or occlusion. RESULTS: Compared with IA-DSA, both teams detected significantly more arterial segments with CE-MRA, both above and below the knee (team 1: above knee 7.0 versus 5.2, P = 0.002, and below knee 8.5 versus 5.4, P < 0.001; team 2: above knee 7.1 versus 5.4, P = 0.004, and below knee 8.3 versus 5.9, P < 0.001). Interobserver agreement between the 2 teams with regard to presence of arteries and the presence of stenoses and/or occlusions yielded kappa values of 0.76 (95% confidence interval 0.71-0.81) for IA-DSA and 0.73 (95% confidence interval 0.66-0.80) for CE-MRA. Treatment was changed based on the CE-MRA findings in 8/23 (35%) patients. CONCLUSIONS: In the present study CE-MRA detected more patent arteries than IA-DSA in patients with chronic critical ischemia and tissue loss. CE-MRA can modify the choice of therapeutic strategy in these patients.

Aged↗

PubMed2005

Computed tomography angiography versus digital subtraction angiography in vascular mapping for planning of microsurgical reconstruction of the mandible.

The aim of this work was to compare the potential of computed tomography angiography (CTA) with that of digital subtraction angiography (DSA) in vascular mapping of the external carotid artery (ECA) branches for planning of microvascular reconstructions of the mandible with osteomyocutaneous flaps. In 15 patients CTA and DSA were performed prior to surgery. Selective common carotid angiograms were acquired in two projection for both sides of the neck. Sixteen-slice spiral computed tomography was performed with a dual-phase protocol, using the arterial phase images for 3D CTA reconstruction. Thin-slab maximum intensity projections and volume rendering were employed for postprocessing of CTA data. The detectability of the different ECA branches in CTA and DSA was evaluated by two examiners. No statistically significant differences between CTA and DSA (p=0.097) were found for identifying branches relevant for microsurgery. DSA was superior to CTA if more peripheral ECA branches were included (P=0.030). CTA proved to be a promising alternative to DSA in vascular mapping for planning of microvascular reconstruction of the mandible.

Angiography, Digital Subtraction↗

PubMed2003

Comparison of computed tomographic angiography with digital subtraction angiography in the diagnosis of cerebral aneurysms: a meta-analysis.

OBJECTIVE: To compare a novel diagnostic radiological technique, computed tomographic angiography (CTA), with the standard method, namely digital subtraction angiography (DSA), in the diagnosis of cerebral aneurysms. METHODS: A comprehensive search of the world literature on CTA was performed. Articles that reported on prospective comparisons of CTA and DSA in the evaluation of patients suspected of harboring cerebral aneurysms were selected for data extraction. Suitable statistical methods were applied to the extracted data for meta-analysis. RESULTS: Twenty-one references met the criteria for use in the meta-analysis. Unweighted calculations based on data for 1251 patients resulted in a sensitivity of 0.933 (93.3%; range, 75.4-100%) and a specificity of 0.878 (87.8%; range, 0-100%). When the studies were weighted for the number of patients in each study, the sensitivity decreased slightly, to 0.927 (92.7%), and the specificity decreased more substantially, to 0.772 (77.2%). CONCLUSION: On the basis of this meta-analysis, DSA remains the standard method. However, many who use CTA have reported it to be as good as or better than DSA in the diagnosis and treatment of cerebral aneurysms, as well as being of less risk and discomfort to their patients and easier and less expensive to perform.

Angiography, Digital Subtraction↗

PubMed2000

Imaging of aortoiliac arterial disease. Duplex ultrasound and MR angiography versus digital subtraction angiography.

PURPOSE: To evaluate and compare the diagnostic accuracy of duplex ultrasound (US) and MR angiography (MRA) at 1.0 T in aortoiliac arterial disease using digital subtraction angiography (DSA) as the reference standard. In addition, a comparison of the 2D time-of-flight (TOF) and 3D contrast-enhanced MRA (CE MRA) techniques was performed. MATERIAL AND METHODS: Prospectively, 39 patients with symptoms of lower-extremity arterial occlusive disease were examined using US, TOF MRA, CE MRA and DSA. Significant lesions (stenosis > or =50%) and occlusions were evaluated blindly for each method. RESULTS: For all segments, the sensitivity for US, TOF MRA and CE MRA with regard to significant lesions was 0.72, 0.81 and 0.81, respectively, and the specificity for each was 0.97, 0.91 and 0.92, respectively. For significant lesions above the inguinal ligament the corresponding sensitivity was 0.84, 0.89 and 0.94 and the specificity 0.93, 0.82 and 0.73, respectively. The specificity was higher when the two MRA methods were combined. TOF MRA overgraded 7 segments as occluded. In most cases, the length of the occlusions was correctly determined on CE MRA, overestimated on TOF MRA and uncertain on US. CONCLUSION: Neither US nor MRA were sufficiently accurate to fully replace angiography. MRA was preferable to US as a non-invasive test when vascular intervention was contemplated. Although CE MRA was superior to TOF MRA, the most accurate results were achieved when the two methods were combined.

Aged↗

PubMed1999

Comparison of treatment plans for lower extremity arterial occlusive disease made with electrocardiography-triggered two-dimensional time-of-flight magnetic resonance angiography and digital subtraction angiography.

BACKGROUND: The purpose of the study was to determine whether preoperative treatment plans for patients with lower extremity ischemia can be made with electrocardiography (EKG)-triggered two-dimensional (2D) time-of-flight (TOF) magnetic resonance angiography (MRA) as accurately as digital subtraction angiography (DSA). METHODS: Forty patients were prospectively evaluated with the combination of EKG-triggered 2D TOF MRA, DSA, and pulse volume recordings. Blinded reviewers graded arterial segments for disease severity. Accuracy of separate MRA- and DSA-based treatment plans was compared with the procedures performed based on all available information. RESULTS: There was an 86% exact match between MRA- and DSA-based plans (92% MRA and 94% DSA accuracy). The MRA-based plan accurately predicted 90% of suprainguinal and 95% of infrainguinal procedures, whereas the DSA-based plan accurately predicted 100% of suprainguinal and 85% of infrainguinal procedures. Two-year primary patency was 83% for all procedures. Radiologists' review of disease severity resulted in a mean exact correlation between studies of 81% (kappa = 0.64). The agreement between radiologists interpreting the MRA was 84% (kappa = 0.7) compared with 82% (kappa = 0.66) for the DSA. CONCLUSIONS: MRA- and DSA-based preoperative management plans were of comparable efficacy. Significant interobserver variability was seen with the interpretations of both preoperative studies. EKG-triggered 2D TOF MRA can be used to plan arterial reconstructions; however, all patients require arterial pressure measurements prior to suprainguinal repair and confirmatory intraoperative angiography during infrainguinal revascularization.

Aged↗

PubMed2006

Multislice computed tomographic angiography versus digital subtraction angiography in the follow-up of nitinol stents in the superficial femoral artery.

PURPOSE: To compare quantitative and qualitative parameters obtained from digital subtraction angiography (DSA) with multislice computed tomographic angiography (MSCTA) in the follow-up of superficial femoral artery (SFA) stents. METHODS: Thirteen patients who had SMART stents implanted in the SFA were examined systematically with DSA and MSCTA (16-row scanner) at 6 months. Quantitative analysis and morphological assessment were performed on DSA images by an independent core laboratory, while the MSCTA images were analyzed by 2 radiologists in consensus. DSA measurements included stent length, minimal lumen diameter and reference diameter at mid stent and 5 mm either side of the stent, and percentage of stenosis. For MSCTA images, lumen area and the minimum, maximum, and mean diameters were also recorded. The images were analyzed qualitatively for diameter stenosis (<50%, 50% to 70%, 71% to 99%, and occlusion), bends, fractures, and calcifications. RESULTS: There were no statistical differences between lengths of stented segments, diameter measurements, or percentages of stenosis from DSA and MSCTA images. The Bland-Altman method showed good agreement between the 2 methods of measurement. MSCTA detected in-stent proliferation with a diameter stenosis <50% in all 13 cases diagnosed on DSA (there was no stenosis >50%). There were no bends or stent fractures on either set of images. The agreement between DSA and MSCTA for the presence and grading of calcifications was moderate (kappa=0.5). CONCLUSION: MSCTA provided quantitative and qualitative data comparable with DSA in the analysis of SFA nitinol stents.

Aged↗

PubMed1999

Computed tomographic angiography versus digital subtraction angiography for the diagnosis and early treatment of ruptured intracranial aneurysms.

OBJECTIVE: Computed tomographic angiography (CTA) is a rapid and minimally invasive method of detecting intracranial aneurysms. We wished to determine whether CTA could replace digital subtraction angiography (DSA) in the diagnosis and operative planning of ruptured cerebral aneurysms. METHODS: In a prospective study, patients with subarachnoid hemorrhage diagnosed by plain computed tomography underwent CTA, DSA, or both. Computed tomographic scans and CTA studies were first reviewed by the treating surgeon, along with a neuroradiologist, and a decision to proceed to DSA or directly to surgery was made on the basis of the type and quality of information provided by CTA. All patients underwent postoperative DSA. RESULTS: A total of 173 patients were studied. In 24 patients, both CTA and DSA were negative for a source of subarachnoid hemorrhage. Twelve patients underwent DSA without prior CTA because a technologist capable of performing CTA was not available when the patient was evaluated. Nine patients in poor neurological condition underwent CTA, and all tested positive for aneurysms but died without surgical intervention. Of the 126 patients who underwent CTA and surgery, 65 (52%) also required preoperative DSA. The decision to proceed to DSA after CTA was influenced by aneurysm location; posterior communicating artery (62%) and posterior circulation locations (67-75%) more commonly proceeded to DSA than middle cerebral artery aneurysms (34%; 0.025 > P > 0.01). The sensitivity and specificity of CTA for the detection of all aneurysms, ruptured and unruptured, in the group of patients who underwent both types of angiograms preoperatively were 84 and 100%, respectively. In the group of 61 patients in whom aneurysm surgery was performed on the basis of CTA results alone, the sensitivity and specificity for the detection of all aneurysms, as compared with postoperative DSA, were 90 and 100%, respectively. Missed aneurysms (n = 24) were always small (<4 mm) and were usually found in patients with multiple aneurysms in whom the larger, ruptured aneurysm was identified by CTA. In one patient, the aneurysm missed by preoperative CTA would have resulted in a different operation if detected preoperatively. CONCLUSION: It is possible to proceed to ruptured aneurysm repair entirely on the basis of good-quality CTA studies that demonstrate an aneurysm consistent with the pattern of bleeding observed on plain computed tomography (48% of the patients in this series and most common middle cerebral artery aneurysms). However, detection of small unruptured aneurysms in patients with multiple lesions remains a problem.

Adult↗

PubMed1991

Left ventricular dual-energy digital subtraction angiography: a motion immune digital subtraction technique.

Digital subtraction angiography (DSA) allows quantitative analysis of ventricular function via densitometric and parametric imaging techniques. However, DSA is limited by the artifacts in temporal subtraction images that result from patient and cardiac motion. Dual-energy subtraction imaging is insensitive to motion. This study evaluated the initial application of dual-energy subtraction in cardiac patients. The image quality of dual-energy subtraction left ventriculograms obtained from a pulmonary artery injection of contrast was assessed in 13 patients, ranging in weight from 54 to 100 kg. The dual-energy images were compared with left ventricular images obtained using standard left ventricular injection cine angiography. End-systolic and end-diastolic ventricular volumes calculated from the cine (C) and dual-energy (DE) images using the Area-Length method were compared. The resulting regression line was DE = 0.98 C+ 7.0 ml, and the r value was 0.987. Dual-energy subtraction provided good left ventricular visualization, free from misregistration artifacts, even during patient motion.

Adult↗

PubMed1985

A comparison of angiography, intravenous digital subtraction angiography and duplex ultrasound in the diagnosis of carotid artery atherosclerosis.

Duplex ultrasonography and intravenous digital subtraction angiography (IV-DSA) were used as the initial diagnostic studies in 124 patients referred for evaluation of neurological disorders possibly related to carotid bifurcation disease in the neck. Conventional angiograms were subsequently performed in 29 patients. Diagnostic images were obtained in 100% of the angiograms, 94% of the duplex ultrasonograms and 89% of the IV-DSA studies. Using the angiogram as the reference standard for plaque detection, duplex ultrasonography had a sensitivity of 0.93 and specificity of 0.83. Doppler velocity ratio alone was used to detect all patients with angiographically demonstrated disease but demonstrated a specificity of only 0.35. IV-DSA showed a sensitivity of 0.93 and specificity of 0.91. IV-DSA and duplex ultrasonography agreed in the assessment of degree stenosis in over 90% of cases and we conclude that these two modalities have approximately the same sensitivity and specificity for detecting atherosclerotic disease at the carotid bifurcations.

Adult↗

PubMed2005

Patient with Leriche's syndrome and concomitant superior mesenteric aneurysm: evaluation with contrast-enhanced three-dimensional magnetic resonance angiography, computed tomography angiography and digital subtraction angiography.

Conventional angiography is regarded as the gold standard in vascular imaging but it is invasive, and difficulty may be encountered in the evaluation of aortic occlusion disease. Superior mesenteric artery aneurysm is an uncommon disease, which can result in life-threatening haemorrhage after rupture. With the rapid development of computed tomography angiography (CTA) and magnetic resonance angiography (MRA), high-quality images of the vascular system can be obtained in a non-invasive manner. We report a case of Leriche's syndrome with concomitant superior mesenteric aneurysm using contrast-enhanced 3-D CTA and MRA, with digital subtraction angiography correlation.

Aneurysm↗

PubMed2005

Stenosis detection with MR angiography and digital subtraction angiography in dysfunctional hemodialysis access fistulas and grafts.

PURPOSE: To prospectively assess three-dimensional contrast material-enhanced magnetic resonance (MR) angiography for stenosis depiction in malfunctioning hemodialysis arteriovenous fistulas (AVFs) and grafts (AVGs), as compared with digital subtraction angiography (DSA). MATERIALS AND METHODS: Ethical review board approval and written informed consent were obtained. MR angiography and DSA were performed in 51 dysfunctional hemodialysis fistulas and grafts in 48 consecutive patients. Vascular tree of accesses was divided into between three and eight segments depending on access type (AVF or AVG) and length of venous outflow. Images obtained with MR and DSA were interpreted by two MR radiologists and two interventional radiologists, respectively, who were blinded to information from each other and other studies. DSA was reference standard for stenosis detection. Sensitivity, specificity, and predictive values with 95% confidence intervals (CIs) of contrast-enhanced MR in detection of vascular segments containing hemodynamically significant (> or =50%) stenosis were calculated. Linear-weighted kappa statistic was calculated for contrast-enhanced MR and DSA to determine interobserver agreement regarding stenosis detection. RESULTS: A total of 282 vascular segments were evaluated. Contrast-enhanced MR depicted three false-positive stenoses and all but two of 70 significant stenoses depicted with DSA. Sensitivity, specificity, and positive and negative predictive values of MR in detection of vessel segments with significant stenoses were 97% (95% CI: 90%, 99%), 99% (95% CI: 96%, 100%), 96% (95% CI: 88%, 99%), and 99% (95% CI: 97%, 100%), respectively. MR demonstrated significant stenosis in four of five nondiagnostic DSA segments, whereas DSA showed no significant stenosis in four nondiagnostic MR segments. Linear-weighted kappa statistic for interobserver agreement regarding stenosis detection was 0.92 (95% CI: 0.89, 0.95) for MR and 0.95 (95% CI: 0.92, 0.97) for DSA. CONCLUSION: MR angiography depicts stenoses in dysfunctional hemodialysis accesses but has limited clinical value as result of current inability to perform MR-guided access interventions after stenosis detection. MR of dysfunctional access should be considered only if nondiagnostic vascular segment is present at DSA.

Adult↗

PubMed1997

Comparison of two-dimensional time-of-flight dynamic magnetic resonance angiography with digital subtraction angiography in popliteal artery entrapment syndrome.

OBJECTIVE: To assess dynamic magnetic resonance angiography (MRA) as an alternative to catheter angiography in patients with popliteal artery entrapment syndrome (PAES). PATIENTS AND METHODS: Nine patients with surgically proven PAES underwent provocation digital subtraction angiography (DSA) and 2-dimensional time-of-flight dynamic MRA of the popliteal fossae (total of 17 limbs). Eight normal volunteers also underwent dynamic MRA (total of 16 limbs). Two observers blinded to the surgical findings and the results of DSA independently evaluated the 33 limbs of the 17 subjects on the basis of maximum-intensity projection images and transverse MRA source images. The degree of stenosis was graded and compared with that indicated by DSA. RESULTS: Among the 17 limbs of patients with surgically proven PAES, dynamic MRA suggested the correct diagnosis in 13 (76%) by indicating stenosis greater than 50%. Dynamic MRA indicated stenosis of 1% to 50% for 4 (25%) of the 16 normal limbs and no stenosis in the other 12 normal limbs (i.e., no false positive results). CONCLUSION: Catheter angiography is not necessary if dynamic MRA indicates stenosis of greater than 50% in patients with clinical suspicion of PAES, but is recommended if dynamic MRA indicates stenosis of 1% to 50%.

Adolescent↗

PubMed2003

Contrast material-enhanced, moving-table MR angiography versus digital subtraction angiography for surveillance of peripheral arterial bypass grafts.

PURPOSE: To assess the accuracy of moving-table MR angiography (MRA) in the evaluation of peripheral bypass grafts. MATERIALS AND METHODS: There were 39 patients who had had peripheral bypass graft surgery and then subsequently underwent digital subtraction angiography (DSA) and contrast material-enhanced MRA, which was performed with moving-table software on a 1.0-T system before and during administration of 40 mL gadolinium. For evaluation, every bypass graft was divided into three parts and every leg into 14 segments. Disease severity was scored in four categories (0%-29%, 30%-69%, 70%-99%, 100%). Results were compared with those of the DSA. A total of 147 bypass graft segments and 938 vessel segments were classified. RESULTS: In 132 of the assessable 147 bypass segments, disease gradings with both methods were congruent; however, 13 stenoses were misinterpreted by MRA for one grade and two additional lesions by two grades, leading to an accuracy in precise stenoses detection of 89.9%. The sensitivity and specificity values in the detection of bypass graft stenoses >69% (grade 3 + 4 lesions) reached 90.0% and 98.3%, respectively. In 821 of 938 vessel segments the accuracy of MRA in stenoses detection reached 87.5%. The sensitivity and specificity values in the detection of grade 3 + 4 lesions were 95.6% and 94.0% for the native vessels, respectively. CONCLUSION: Moving-table MRA was as accurate in assessing bypass grafts as it was for the native arteries and showed a great accuracy in stenosis detection compared with DSA. Therefore, MRA is a promising modality for bypass graft surveillance and might be a noninvasive alternative to DSA in this regard.

Aged↗