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At least 361 records · Page 20Linked to original sources

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↗

PubMedDate not supplied

Comparison of two-dimensional MR digital subtraction angiography of the lower extremity with x-ray angiography.

PURPOSE: To perform a preliminary evaluation of the diagnostic accuracy of contrast-enhanced, two-dimensional (2D) magnetic resonance (MR) digital subtraction angiography (DSA) of the lower extremity by comparison with x-ray angiography (XRA). MATERIALS AND METHODS: Forty lower extremities in 22 patients were imaged at multiple levels with both XRA and 2D MR DSA. Images were retrospectively analyzed by three radiologists in a randomized blinded manner. Seventeen vascular segments were graded as an insignificant lesion, a significant lesion, or as an occlusion. With the use of segments well depicted with XRA as the gold standard, the sensitivity, specificity, and accuracy of 2D MR DSA, as compared with XRA, were evaluated. The McNemar-Stuart-Maxwell test was performed to determine the significance of any differences found. RESULTS: Three hundred eighty-three arterial segments were evaluated with both techniques. Three hundred one segments were well depicted with XRA. There was no significant difference between 2D MR DSA and XRA for assessing the degree of occlusive disease in these 301 segments (.25 < P < .5). The sensitivity, specificity, and diagnostic accuracy of 2D MR DSA were found to be 90%, 98%, and 93%, respectively. CONCLUSION: Two-dimensional MR DSA is an accurate method for assessing arterial lesions in the lower extremity.

Adult↗

PubMed2001

Volume coronary angiography using targeted scans (VCATS): a new strategy in MR coronary angiography.

The aim of this study was to explore the clinical possibilities of a new strategy for magnetic resonance imaging of the coronary arteries. Thirteen patients were studied by volume coronary angiography using targeted scans (VCATS) to visualize the major coronary arteries in a series of breath-holds. The proximal coronary arteries were clearly seen in 92% and the mid segments in 50-70% of the patients. VCATS was able to visualize a total vessel length of the left main (LM) (mean: 9.4+/-3.4 mm), of the left anterior descending (LAD) 69+/-20 mm, of the right coronary artery (RCA) 90+/-33 mm and of the left circumflex (LCX) 41+/-18 mm. There was a reasonable correlation between the VCATS and conventional coronary angiography (CAG) for vessel diameter (r = 0.71), with a slight overestimation of 0.7 mm by VCATS. There were nine significant stenoses present of which six were correctly detected, three were missed and one false positive was present. VCATS is fast strategy for visualizing the major coronary artery branches and has the potential to detect significant stenoses in these branches.

Coronary Angiography↗

PubMed2000

Gadolinium-enhanced magnetic resonance angiography, digital subtraction angiography and duplex of the iliac arteries compared with intra-arterial pressure gradient measurements.

PURPOSE: to compare gadolinium-enhanced magnetic resonance angiography (Gd-MRA), digital subtraction angiography (DSA) and duplex of the iliac arteries with intra-arterial pressure gradient measurement as the reference method. MATERIALS AND METHODS: Gd-MRA, DSA and duplex examinations of the iliac arteries were performed in 30 patients (60 arteries) with lower-limb arterial occlusive disease. In 29 arteries, pressure measurements were made (n=25) or the artery was found to be occluded on catheterisation (n=4). An aortofemoral peak systolic pressure gradient of 20 mmHg or more was regarded as haemodynamically significant. Stenoses with a diameter reduction of 50% or more on MRA or DSA, or an increase in peak systolic velocity greater than 150% (duplex) were considered significant. MRA examinations were evaluated by means of maximum intensity projections (MRA-MIP) and using source images and curved multiplanar reconstruction (MRA-MPR). RESULTS: the sensitivity (specificity) for a significant iliac artery stenosis were 81% (75%) for MRA-MIP, 76% (75%) for MRA-MPR, 86% (88%) for DSA, and 72% (88%) for duplex. CONCLUSION: with intra-arterial pressure measurements as the reference method, similar results were achieved with Gd-MRA, DSA and duplex concerning the detection of haemodynamically significant iliac artery stenoses. The use of source images and multiplanar reconstructions resulted in higher accuracy for the detection of occlusions.

Aged↗

PubMed2002

Pedal artery imaging--a comparison of selective digital subtraction angiography, contrast enhanced magnetic resonance angiography and duplex ultrasound.

OBJECTIVE: to evaluate selective digital subtraction angiography (DSA), contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (duplex) in preoperative pedal artery imaging. MATERIAL AND METHODS: DSA, CE-MRA and duplex were studied prospectively in 37 patients suffering from critical leg ischaemia. Two radiologists independently reviewed both the CE-MRA and DSA images. The pedal vessels were scored on a scale from 0 to III (0=vessel not visualised, I=vessel faintly visualised, II=stenosis >50%, III=vessel without relevant stenosis). Duplex ultrasound was performed by an angiologist blind to both the DSA and MRA findings and the pedal arteries were scored 0-III according to their diameter. Each examiner named the pedal artery best suitable for bypass surgery. Agreement in artery assessment was expressed as kappa values. Patency of the bypass at 30 days was used as validation of the artery's suitability as the run-off vessel. RESULTS: interobserver agreement for DSA (weighted Kappa 0.63, CI 0.53-0.73 and CE-MRA (weighted kappa 0.60, CI 0.5-0.7) was moderate to substantial. CE-MRA depicted significantly more vascular segments than DSA (p congruent with 0.0001).In the prediction of the distal outflow vessel duplex and CE-MRA proved to be superior to DSA. CONCLUSION: because of the moderate inter-observer agreement it may be questionable to regard selective DSA as gold standard imaging procedure in preoperative pedal artery imaging. CE-MRA and duplex are very helpful in assessing the pedal artery morphology and should be used if selective DSA does not sufficiently depict the pedal vasculature.

Aged↗

PubMed2000

Comparative performance of magnetic resonance angiography and conventional angiography in moyamoya disease.

Patients with moyamoya disease verified by conventional cerebral angiography (CCA) were evaluated by means of magnetic resonance angiography (MRA), in order to clarify its advantages and limitations in comparison with CCA. This retrospective study was carried out in 13 hemispheres of seven patients with moyamoya disease (including one atypical patient). In MRA, magnetisation transfer contrast (MTC) and maximal intensity projection (MIP) techniques were used. A good correspondence between MRA and CCA was noted in 11 hemispheres (86.4%) on evaluating stenotic lesions and overestimation in the remaining 2. Underestimation of moyamoya vessels in MRA was noted in 3 hemispheres, since well developed moyamoya vessels were detectable, while poorly developed ones were not. No difference between MRA and CCA findings was found in 10 hemispheres (76.9%). MRA tends to overestimate the stenosis and underestimate moyamoya vessels. These characteristics may lead to wrong classification in the angiographic grade of patients with early and advanced stages and should be taken into consideration in interpreting MRA images of moyamoya disease (compatible rate of grade between MRA and CCA; 84.6%). In conclusion MRA with MTC and MIP techniques offers an acceptable quality of assessment of stenotic lesions and moyamoya vessels. MRA is a useful follow up method at present and in the near future it may replace CCA as the initial diagnostic tool.

Adult↗

PubMed2002

Treatment of ruptured anterior circulation aneurysm based on computerized tomography angiography: surgical results and indications for additional digital subtraction angiography.

The purpose of this study is to determine whether or to what extent computerized tomography angiography (CTA) can replace digital subtraction angiography (DSA) for ruptured anterior circulation cerebral aneurysms. We reviewed our patients in two different periods and evaluated in what cases we should perform additional DSA. In the first period, both CTA and DSA were routinely performed except on patients that were suitable for emergent surgery with CTA only. In the second period, only CTA was performed routinely as a preoperative workup and if further information was necessary, additional DSA was performed. A total of 106 (52 in the first period and 54 in the second period) patients were included. Characteristics of the patients and outcome at three months were similar in the two periods. In the second period, ten patients underwent additional DSA. Our results suggest that most of cases with ruptured anterior circulation aneurysms can be successfully treated on the basis of CTA alone.

Adult↗

PubMed2004

[Comparison of contrast-enhanced MR angiography of the aortoiliac vessels using a 1.0 molar contrast agent at 1.0 T with intra-arterial digital subtraction angiography].

PURPOSE: To evaluate the diagnostic accuracy of contrast-enhanced MR angiography (CE-MRA) using a 1.0 molar contrast agent at 1.0 T for the diagnosis of abdominal aortic aneurysms and stenoses of renal or iliac arteries in comparison to intraarterial digital subtraction angiography (DSA). MATERIALS AND METHODS: A total of 19 patients with the suspicion of abdominal aortic aneurysm or stenosis of renal or iliac arteries were examined with CE-MRA at 1.0 T. Intra-arterial DSA served as reference in all cases. After test bolus tracking, 10 or 8 ml of the 1.0 molar contrast agent Gadobutrol corresponding to a dose of 0.1 - 0.15 mmol/kg bw were injected and imaging performed using a FLASH-3D sequence. To evaluate the interobserver-variability, the blinded images were analyzed by two radiologists. Besides the rating of overall image quality on a 4-point-scale, the images were evaluated for aneurysms and arteriosclerotic lesions with a stenosis of < 50 % or > 50 % or occlusion. RESULTS: A total of 144 segments were analyzed. The mean value of the CE-MRA image quality was 3.4 on a 4-point-scale. The sensitivity of CE-MRA in depicting relevant pathological findings was 96 % and the specificity 99 %. The positive predictive value was 96 % and the negative predictive value 99 %. Inter-observer variability was low with a kappa value of 0.82. CONCLUSION: CE-MRA using a 1.0 molar contrast agent at 1.0 T enables an excellent diagnosis or exclusion of pathologies of the aortoiliac vessels.

Adult↗

PubMed1996

[3-D-TONE magnetic resonance angiography in the detection of intracranial aneurysms compared with digital subtraction angiography. A prospective study].

PURPOSE: To evaluate the efficiency and accuracy of the optimized 3-D-MT-TONE-magnetic resonance angiography (MRA) with that of intraarterial digital subtraction angiography (DSA) in the detection of intracranial aneurysms. MATERIAL AND METHODS: From March 1994 to March 1995 30 patients with 38 aneurysms were prospectively subjected to MRA as well as to DSA. Respiratory insufficient patients were excluded from MRA. RESULTS: The aneurysm size ranged from 3-50 mm with an average size of 9 mm. Correct diagnosis was done in 33 aneurysms (86.8%) in 26 of the patients. In 4 patients (13.3%) with 5 aneurysms, the blinded readers made an incorrect diagnosis due to degradation of image quality. One (2.6%) aneurysm was falsely described via MRA as well as via DSA. The sensitivity was 86.8%. In the control group of 30 patients three aneurysms were found, therefore the specificity was 90% and we could calculate a positive predictive value of 97.1%, a negative predictive value of 84.4% and a correct diagnosis of 90.1%. CONCLUSION: Our results show that MT-TONE-MRA is a useful non-invasive technique with improved vascular detail and vascular background for detection of intracranial aneurysm. Further technical improvements are necessary for better visualisation of pathological findings in the carotid siphon, where only 60% of the aneurysms could be clearly detected.

Adult↗

PubMed2001

Noninvasive investigation for renal artery stenosis: contrast-enhanced magnetic resonance angiography and color Doppler sonography as compared to digital subtraction angiography.

INTRODUCTION: The question about the most appropriate non-invasive method for detecting a renal artery stenosis (RAS) when comparing contrast enhanced magnetic resonance angiography (MRA) and color Doppler sonography (CDS) is still under discussion. Therefore we conducted a prospective study in order to evaluate both methods as compared to digital subtraction angiography (DSA). PATIENTS/METHODS: Thirtysix consecutive patients (53,9 +/- 13,7 years) with suspected RAS were investigated. MRA was performed using gadolinium for contrast enhancement. CDS was performed using a 2.5 and 3,5 MHz transducer. A peak systolic velocity (Vmax) >200 cm/sec within renal arteries and/or a side to side difference of the resistive index (RI) of >0,05 were used to discriminate stenosis. A diameter reduction of > or = 60% by DSA was considered a stenosis relevant to the patient. RESULTS: Sixty-eight main renal arteries and 9 accessory vessels were detected by DSA. Twenty main and 3 accessory arteries were found to be stenosed > or = 60%, while 4 main and 1 accessory artery presented with occlusion. MRA detected 70 renal vessels (65 main and 5 accessory arteries). Twenty-one stenosed arteries and 4 occluded vessels were correctly diagnosed by MRA. With CDS 68 renal vessels (62 main and 6 accessory arteries) could be visual- ized out of which 21 stenoses were diagnosed because of increased Vmax and 6 stenoses were detected because of a side to side difference of RI. For main renal arteries sensitivities and specificities were 96% and 86% for MRA and 96% and 89% for CDS. CONCLUSIONS: MRA and CDS are both comparable methods for detection of a renal artery stenosis > or = 60%. Despite several limitations, CDS can at the moment still be favored as a screening method.

Adult↗

PubMed2002

Evaluation of arterial bypass grafts of the pelvic and lower extremities with gadolinium-enhanced magnetic resonance angiography: comparison with digital subtraction angiography.

RATIONALE AND OBJECTIVES: The aim of this study was to compare contrast-enhanced magnetic resonance angiography (CE MRA) with digital subtraction angiography (DSA) in the assessment of patency and stenoses in bypass grafts. METHODS: Fifteen patients were examined with both CE MRA and DSA. Fifteen bypass grafts were evaluated by four readers for potential stenosis in five locations. The stenoses were classified in five types: 1 (0% to 24% stenosis), 2 (25% to 49%), 3 (50% to 74%), 4 (75% to 99%), and 5 (occlusion). RESULTS: Using both techniques, 70 of 75 evaluated locations (93.3%) were classified identically. This included six stenoses < 50% and six stenoses > 50%, respectively. Four of five overestimations of stenoses were scaled in DSA as stenoses type 1. One stenosis was categorized as type 3 in DSA. Sensitivity for CE MRA for detecting stenoses >or= 25% was 100% and the specificity 90%. Interobserver agreement for all evaluations was 0.77 (Spearman rank correlation test). CONCLUSION: In the assessment of low-grade stenosis in bypass grafts, CE MRA overestimates stenoses slightly but yields good results in comparison with DSA.

Angiography, Digital Subtraction↗

PubMed2002

Time-resolved contrast-enhanced magnetic resonance angiography of the carotid arteries: diagnostic accuracy and inter-observer variability compared with selective catheter angiography.

RATIONALE AND OBJECTIVES: To assess the diagnostic accuracy and interobserver variability of contrast-enhanced magnetic resonance angiography (CE-MRA) in a time-resolved technique compared with digital subtraction angiography (x-ray DSA) in patients with suspected stenoses of the internal carotid artery. MATERIALS AND METHODS: A total of 43 patients were enrolled in this prospective study. All patients underwent selective x-ray DSA involving a total of 84 carotid arteries. CE-MRA was performed in a time-resolved technique with a fast gradient-echo sequence on a 1.5 T MR scanner: TR 3.8 milliseconds, TE 1.49 milliseconds. Four consecutive measurements, each a duration of 10 seconds, were performed with omission of measuring bolus transit time. Four independent radiologists scored the degree of stenosis. The interobserver variability was calculated for CE-MRA and x-ray DSA. RESULTS: In the 43 cases, at least one MRA measurement showed arterial contrast without venous degradation. Compared with x-ray DSA the mean sensitivity and specificity for grading stenosis > or = 70% were 98% and 86%, respectively. The interobserver agreement was substantial with no significant difference between CE-MRA (kappa value 0.794) and x-ray DSA (kappa value 0.786). CONCLUSIONS: The short acquisition time of a fast CE-MRA sequence allows a selective visualization of the internal carotid arteries without degradation from venous enhancement. It is a reliable method with a good interobserver agreement.

Adult↗

PubMedDate not supplied

Agreement of multislice CT angiography and MR angiography in assessing the degree of carotid artery stenosis in consideration of different methods of postprocessing.

OBJECTIVE: We investigated the agreement of multislice computed tomography angiography (CTA) and magnetic resonance angiography (MRA) in the quantitative measurement of carotid artery stenosis. The dependency of the agreement of the chosen postprocessing procedures was also investigated. METHODS: Fifty consecutive symptomatic patients were included in this study. In all patients, a CTA was performed with a 16-slice CT scanner. Within 30 days, the extracranial vessels were examined using a combined time-of-flight and contrast-enhanced MRA. The CT data sets were used to calculate the degree of stenosis according to the North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial, and Common Carotid methods by means of the 1-mm thick, transverse raw data (RD), a sagittal maximum-intensity projection reconstruction, and sagittal multiplanar reconstruction. In addition, a semiautomated analysis was done using a specialized postprocessing software. For all combinations of postprocessing procedures and methods of calculating the degree of stenosis, the correlation coefficient and the agreement based on Bland/Altman plots were calculated. RESULTS: Eleven of the 100 primarily included carotid arteries could not be evaluated. The correlation coefficients for all combinations were comparable and lied in the interval between 0.932 and 0.787. The best correlation was found for the combination of RD/sagittal multiplanar reconstruction and ECST method. The evaluation of the agreement gave a systematic overestimation of CTA between 1.9% and 10.7% with a 95% confidence interval between +/-26.7% and +/-43.3%. With the semiautomated postprocessing software, additional 33 vessels could not be evaluated. The agreement of the calculated degrees of stenoses was worse than that of the planar procedures. CONCLUSIONS: CTA and MRA had a feasible agreement in measuring the degree of stenosis of the carotid arteries. The best result could be obtained for the evaluation of the RD and the NASCET method. In this case one has to take into account a systematic overestimation of CTA of 1.9%. The combination with an additional reconstructive postprocessing procedure did not improve the result but might be useful for the radiologist to identify the location of the closest narrowing.

Angiography↗

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↗

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↗

PubMed2003

Gadolinium-enhanced three-dimensional magnetic resonance angiography versus conventional digital subtraction angiography: which modality is superior in evaluating living kidney donors?

This study evaluates the correlation of magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) with the operative vessel findings in living kidney donors. The intraoperative vessel findings of 52 living renal donors were compared with the preoperative diagnoses of each imaging technique. Sixty-seven arteries were found during explantation. Forty kidneys showed a single arterial blood supply, and 12 kidneys showed a multiple arterial blood supply. No advantage of either imaging method was found for arterial imaging. There were 55 veins identified during organ harvesting. MRA could not determine the venous system in one donor (1.9%) and failed to detect one small pole vein in another. DSA did not yield a venous diagnosis in seven patients (13.5%) and yielded misdiagnoses in four patients. The correct diagnosis of renal donor veins differed significantly in favor of MRA (kappa 0.79 vs. 0.45; P=0.008). MRA is superior to DSA in assessing the renal vasculature in living kidney donors.

Angiography↗

PubMed2005

Contrast-enhanced three-dimensional fast-spoiled gradient magnetic resonance angiography of the renal arteries for potential living renal transplant donors: a comparative study with digital subtraction angiography.

Preoperative assessment of the arterial anatomy of prospective renal donors is essential. Various non-invasive techniques are used for such evaluation. We conducted this study using contrast-enhanced 3-D fast-spoiled gradient (CE 3-D FSPGR) magnetic resonance angiography (MRA) on a 1.0 Tesla magnet, for preoperative definition of the renal arteries. Forty-five preoperative living renal donors underwent CE 3-D FSPGR MRA of the renal vessels and the results were compared with conventional digital subtraction angiography (DSA). The renal vascular anatomy, both normal and with variations, was satisfactorily defined in all 45 cases with CE 3-D FSPGR MRA. Fifteen cases showed an accessory or aberrant arterial supply. A small aneurysm was shown in one case. All cases compared well with conventional DSA. Our study revealed that CE 3-D FSPGR MRA on a lower field strength magnet is accurate in defining the renal vascular anatomy and its variations.

Aneurysm↗

PubMed2004

Comparison of ultrasonography, CT angiography, and digital subtraction angiography in severe carotid stenoses.

Digital subtraction angiography (DSA) is considered to be the 'gold standard' for confirmation of severe (70-99%) stenoses of internal carotid arteries (ICAs). However, it is associated with a risk of complications. The aim of this study was to assess the accuracy of ultrasonography (US), computed tomographic angiography (CTA), and their combined use for the detection and quantification of severe carotid stenoses, when compared with DSA. Severe ICA stenoses were diagnosed by US in a set of 29 patients. All patients also underwent CTA and DSA. Sensitivity, specificity, positive (PPV), negative predictive values (NPV), and Pearson's correlation coefficient were used in the evaluation of the percentage of stenosis results. Homogeneity chi2 test was applied when assessing statistical significance. Severe stenosis was diagnosed in 34 ICAs. Two ICAs with uninterpretable CTA finding were excluded. The number of ICAs with stenoses 70-99%/<70%- US 32/0; CTA 29/3; US + CTA 29/3; DSA 24/8. Pearson's correlation coefficient - US 0.601; CTA 0.725; US + CTA 0.773. Sensitivity/specificity/PPV/NPV - US 1.0/0.75/0.75/xxx; CTA 1.0/0.844/0.828/1.0; US + CTA 1.0/0.844/0.828/1.0. Homogeneity chi2 test results - US, P = 0.002; CTA, P = 0.098; US + CTAG, P = 0.098. US in combination with CTA can be used for relatively secure diagnostics of severe ICA stenoses. Thus, invasive DSA can be avoided in a substantial number of patients.

Angiography, Digital Subtraction↗