SEARCH · PubMed Health

Results for “Angiography”

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 127 records · Page 7Linked to original sources

PubMed2001

Carotid artery: elliptic centric contrast-enhanced MR angiography compared with conventional angiography.

PURPOSE: To determine the accuracy of elliptic centric contrast material-enhanced magnetic resonance (MR) angiography by using conventional angiography as the reference standard. MATERIALS AND METHODS: Fifty patients were examined prospectively with contrast-enhanced MR angiography and conventional angiography. The two examinations were performed within 1 week of each other. Two patients underwent conventional angiography of only one carotid artery, which yielded 98 arteries for comparison. RESULTS: With conventional angiography as the reference standard and by using a 70% threshold for internal carotid arterial diameter stenosis, maximum intensity projection (MIP) images had a sensitivity of 93.3%, specificity of 85.1%, and accuracy of 87.6%, whereas reformatted transverse source images had a sensitivity of 83.3%, specificity of 97.0%, and accuracy of 92.8%. Interobserver variability for conventional angiograms was 0.97, for MIP images was 0.91, and for source images was 0.90. The contrast-enhanced MR angiographic technique had a sensitivity of 88.9% and specificity of 58.1% for the presence of irregularity and/or ulceration. All 50 examinations were triggered appropriately so that minimal or no venous signal intensity was depicted. CONCLUSION: Contrast-enhanced elliptic centric three-dimensional MR angiography offers high-spatial-resolution, venous-suppressed images of the carotid arteries that appear to be adequate to replace conventional angiography in most patients examined prior to carotid endarterectomy.

Aged↗

PubMed2000

Diabetes and peripheral arterial occlusive disease: prospective comparison of contrast-enhanced three-dimensional MR angiography with conventional digital subtraction angiography.

OBJECTIVE: The purpose of this study was to compare contrast-enhanced three-dimensional MR angiography with conventional digital subtraction angiography (DSA) for identifying and evaluating arteries of the distal calf and foot in diabetic patients with severe arterial occlusive disease who will undergo distal bypass surgery. SUBJECTS AND METHODS: Twenty-four feet of 24 consecutive patients with diabetes and limb-threatening lower extremity ischemia were prospectively imaged using an ultrafast three-dimensional fast low-angle shot sequence on a 1.5-T MR scanner. All patients also underwent DSA of the diseased extremity within 5 days. Images were interpreted in a randomized manner by two observers in conference. Each lower extremity was divided into seven potential arterial segments. Image analysis included the detection of patent, stenosed, or occluded vessel segments. A vascular surgeon formulated treatment plans on the basis of findings from DSA and then formulated treatment plans on the basis of findings from both DSA and MR angiography. RESULTS: MR angiography was significantly better than DSA in revealing peripheral runoff vessels (p < 0.001). In nine (38%) of the 24 patients, MR angiography showed patent pedal vessels suitable for distal bypass grafting that were not revealed by DSA. Because of the results of MR angiography, treatment plans changed in seven of the nine patients in whom patent vessels were subsequently used as target vessels for distal pedal bypass grafts. CONCLUSION: Contrast-enhanced three-dimensional MR angiography is superior to DSA in revealing patent vessel segments of the foot in diabetic patients with severe arterial occlusive disease. Contrast-enhanced three-dimensional MR angiography should be part of the diagnostic algorithm for patients in whom pedal bypass grafting is a therapeutic option.

Aged↗

PubMed2001

Surveillance of peripheral arterial bypass grafts with three-dimensional MR angiography: comparison with digital subtraction angiography.

OBJECTIVE: The purpose of this study was to use contrast-enhanced three-dimensional MR angiography to assess the patency of peripheral arterial bypass grafts of the lower extremity. SUBJECTS AND METHODS: The study included 39 patients with 45 lower limb grafts. Twenty-eight were saphenous vein grafts, 13 were expanded polytetrafluoroethylene, and two were Dacron grafts. Digital subtraction angiography correlation was available for 30 patients (31 grafts). MR angiography was performed on a 1.5-T system with a multichannel quadrature phased array peripheral vascular coil. The scanning delay was determined with a test bolus technique, using half-time to maximum signal intensity in the graft. Arterial imaging was accomplished with two three-dimensional MR angiography acquisitions with gadopentetate dimeglumine administered using an automated injector. The pelvic and femoral arteries were imaged, the MR table was repositioned, and the lower limb arteries were imaged. The three-dimensional MR angiography sequence used the following parameters: TR/TE, 5.2/1.5 msec; inversion time, 28 msec; flip angle, 30 degrees. The proximal anastomosis, graft, and distal anastomosis were characterized as normal, stenosed, occluded, or ectatic or aneurysmatic. RESULTS: Sensitivity and specificity values for MR angiography regarding the assessment of grafts were 100% for 87 evaluable segments for which digital subtraction angiography correlation was available: stenosis (n = 10), occlusions (n = 9), ectasia or aneurysms (n = 8). Six segments could not be assessed because of the presence of intravascular stents or metallic clips. CONCLUSION: Contrast-enhanced three-dimensional MR angiography is well suited for the characterization of arterial grafts, for planning subsequent vascular interventions, and for excluding further lesions.

Aged↗

PubMed2002

Contrast-enhanced 3D MR angiography of the carotid artery: comparison with conventional digital subtraction angiography.

BACKGROUND AND PURPOSE: Since 1996, several preliminary studies have shown the usefulness of contrast material-enhanced MR angiography for imaging supraaortic vessels. The aim of this study was to compare the accuracy of contrast-enhanced 3D MR angiography with that of digital subtraction angiography (DSA) in the evaluation of carotid artery stenosis. METHODS: A blinded comparison of first-pass contrast-enhanced MR angiography with conventional DSA was performed in 120 patients (240 arteries). MR angiography was performed with a 1.5-T magnet with gradient overdrive equipment, by using a coronal radiofrequency-spoiled 3D fast low-angle-shot sequence after the intravenous injection of gadodiamide. The guidelines of the North American Symptomatic Carotid Endarterectomy Trial for measuring stenosis of the internal carotid artery were applied on maximum intensity projection (MIP) images and conventional catheter angiograms. RESULTS: Grading of stenoses on MR angiograms agreed with grading of stenoses on DSA images in 89% of arteries. In the severe stenosis group (70-99%), agreement was 93%. All internal carotid occlusions (n = 28) and seven of nine pseudo-occlusions were accurately detected with contrast-enhanced MR angiography. The correlation between MR angiography and DSA for determination of minimal, moderate, and severe stenoses and occlusion was statistically significant (r = 0.91, P<.001). CONCLUSIONS: This investigation with a large number of patients confirms that contrast-enhanced MR angiography could become a diagnostic alternative to DSA in the treatment of patients with carotid artery disease.

Adolescent↗

PubMed2004

Evaluation of carotid artery stenosis: contrast-enhanced magnetic resonance angiography compared with conventional digital subtraction angiography.

OBJECTIVE: To compare retrospectively high-resolution contrast-enhanced magnetic resonance angiography with centric k-space filling and digital subtraction angiography in the assessment of degree of carotid artery stenosis. METHODS: Two neuroradiologists independently evaluated 14 carotid arteries (in 7 patients), and the degree of carotid stenosis determined was compared to calculate interobserver reliability. Thirty-six carotid arteries (in 18 patients) were then assessed with both contrast-enhanced magnetic resonance angiography and digital subtraction angiography. The degree of stenosis was determined by consensus, and the findings of the 2 modalities were compared. RESULTS: Close interobserver agreement was found with an intraclass correlation coefficient of 0.98 (95% confidence interval 0.95-0.99). Sensitivity of 86% and specificity of 91% were found for contrast-enhanced magnetic resonance angiography detection of surgically significant carotid stenosis compared with digital subtraction angiography. The Spearman rank correlation test also found a significant correlation (R(s) = 0.90, p < 0.001) in the comparison of the classifications of degree of carotid artery stenosis. CONCLUSION: Contrast-enhanced magnetic resonance angiography shows excellent correlation with digital subtraction angiography for the evaluation of carotid artery disease and has the potential to replace it in the assessment of degree of carotid artery stenosis.

Angiography, Digital Subtraction↗

PubMed2006

Comparison of radiation doses from multislice computed tomography coronary angiography and conventional diagnostic angiography.

OBJECTIVES: The aim of this study was to quantify and compare effective doses from conventional angiography and multislice computed tomography (MSCT) coronary angiography using a 16-slice scanner. BACKGROUND: Multislice computed tomography is now a viable modality for cardiac imaging. However, for any diagnostic use of ionizing radiation, the risk to the patient must be considered and justified. METHODS: Multislice computed tomography angiography and conventional angiography were used to assess 180 patients with suspected coronary artery disease. Estimates of effective dose were derived from exposure data recorded for each patient examination. For each modality, a comparable calculation technique was used, based on Monte Carlo modeling of the standard Cristy phantom. RESULTS: In a subset of 91 directly comparable patients the mean effective dose for MSCT coronary angiography was 14.7 mSv (SD 2.2) and that for conventional angiography was 5.6 mSv (SD 3.6). A significant difference in effective dose was seen between the two protocols. CONCLUSIONS: The mean effective dose for MSCT coronary angiography was significantly higher than that for conventional angiography. As MSCT cardiac scanners become increasingly available, operators must be aware of the radiation dose and the factors that affect it.

Coronary Angiography↗

PubMed1993

A preliminary report comparing magnetic resonance coronary angiography with conventional angiography.

BACKGROUND: The ability to assess the patency of coronary arteries by noninvasive means would represent an important advance. We have developed a magnetic resonance imaging (MRI) coronary angiographic technique that permits the display of areas of abnormal coronary blood flow. We have compared this method with conventional contrast angiography for the identification of coronary-artery stenoses. METHODS: MRI coronary angiography was performed with an electrocardiographically gated sequence in 39 subjects, 33 to 84 years of age, who were scheduled for elective cardiac catheterization with coronary angiography. Sequential overlapping transverse and oblique sections were acquired during periods of breath-holding and were displayed as cine loops for analysis. MRI and conventional angiographic data were compared in a blinded manner. The four major epicardial coronary arteries were classified by MRI coronary angiography as being normal (or having only minimal irregularities) or as having disease that was moderately severe to severe. RESULTS: The sensitivity and specificity of MRI coronary angiography, as compared with conventional angiography, for correctly identifying individual vessels with > or = 50 percent angiographic stenoses were 90 percent and 92 percent, respectively. The corresponding positive and negative predictive values were 0.85 and 0.95, respectively. The sensitivity and specificity of the technique were 100 percent and 100 percent, respectively, for the left main coronary artery, 87 percent and 92 percent for the left anterior descending coronary artery, 71 percent and 90 percent for the left circumflex coronary artery, and 100 percent and 78 percent for the right coronary artery. CONCLUSIONS: MRI coronary angiography provides a new approach to evaluating the patency of coronary arteries. These preliminary data suggest that this technique may provide a noninvasive means of evaluating patients with known or suspected coronary artery disease. At its current stage of development, this procedure may be most helpful for excluding clinically important stenoses in patients referred for diagnostic contrast angiography.

Adult↗

PubMed1994

Evaluation of cerebral aneurysms with helical CT: correlation with conventional angiography and MR angiography.

PURPOSE: To evaluate detection of intracranial aneurysms with helical computed tomography (CT) and compare the results with those of conventional angiography and magnetic resonance (MR) angiography. MATERIALS AND METHODS: Twenty-one patients with 30 intracranial aneurysms were studied with helical CT and conventional angiography; 17 of the patients (24 aneurysms) also underwent MR angiography. RESULTS: All aneurysms 3 mm or larger in greatest dimension were seen with helical CT and MR angiography; no aneurysms smaller than 3 mm were apparent with either modality. Of the 21 aneurysms demonstrated with both helical CT and MR angiography, 11 were seen equally well with both techniques; six were seen better with helical CT owing to flow-related or motion artifact at MR angiography, and four were seen better with MR angiography because calcium partially obscured them at helical CT. CONCLUSION: Helical CT is a promising noninvasive method of imaging the intracranial vasculature and is comparable with standard MR angiographic techniques in demonstrating aneurysms.

Cerebral Angiography↗

PubMed1993

Cervical carotid MR angiography with multiple overlapping thin-slab acquisition: comparison with conventional angiography.

OBJECTIVE: Multiple overlapping thin-slab acquisition (MOTSA) is a hybrid time-of-flight MR angiography technique that combines the advantages of two- and three-dimensional methods. A venetian blind-like artifact, resulting from variations in signal intensity at slab boundaries, is a potentially significant disadvantage. The objective of this study was to determine the accuracy of MOTSA MR angiography for the measurement of stenosis and to evaluate the effectiveness of modifications to reduce the venetian blind artifact. SUBJECTS AND METHODS: Fifty-one consecutive patients undergoing conventional and MR angiography of the carotid arteries for suspected atherosclerotic disease were studied. Methods established in the North American Symptomatic Carotid Endarterectomy Trial (NASCET) were used to measure stenosis. Measurements from the conventional angiograms were compared with those from the MR angiograms. Modifications of the MR angiographic technique that were instituted after the initial 26 patients to reduce the venetian blind artifact included new acquisition parameters and the use of a postprocessing algorithm. RESULTS: After modification, highly significant improvements in Spearman ranked correlation coefficients were observed for MR angiography interobserver comparison (.573 to .974, p < .001) and comparison of conventional and MR angiography (.774 to .949, p < .001). A corresponding reduction was observed in the standard deviation of the difference measurement for percent stenosis for both interobserver (34.5% to 11.7%, p < .001) and intertechnique (22.6% to 12.6%, p < .001) comparisons. In the postmodification group, the interobserver correlation coefficients for conventional and MR angiography were not significantly different (.969 vs .974). The areas under the receiver-operating-characteristic curves used to predict surgically significant disease for the premodification and postmodification groups were 0.79 and 0.98, respectively, for observer A and 0.85 and 0.95, respectively, for observer B. CONCLUSION: Improved acquisition parameters and postprocessing significantly reduce the severity of the venetian blind artifact and increase the accuracy of MOTSA MR angiography in the measurement of percent stenosis. With these improvements, MOTSA MR angiography shows promise for noninvasive evaluation of stenosis of the carotid arteries.

Artifacts↗

PubMed1994

Dynamic contrast-enhanced MR angiography of pulmonary embolism: comparison with pulmonary angiography.

OBJECTIVE: Subsecond contrast-enhanced MR angiography, which is not a flow-based technique and does not require cardiac gating or breath-holding, provides multiplanar, rapid, dynamic visualization of the pulmonary arteries. Accordingly, we evaluated the use of this technique in the diagnosis of thrombi in both the proximal and peripheral portions of the pulmonary arteries. Digital subtraction angiography was used as the gold standard for the diagnosis. SUBJECTS AND METHODS: Twenty-three consecutive patients with suspected pulmonary embolism were included in the study. All patients had intraarterial digital subtraction angiography, which showed emboli in 12 patients (13 proximal and six peripheral emboli). MR angiography was done within 24 hr of digital subtraction angiography. Subsecond contrast-enhanced MR angiograms were obtained in the long axis of each pulmonary artery after a unique injection of contrast medium (0.1 mmol/kg) in an antecubital vein. Fifteen dynamic frames of each pulmonary artery were alternately obtained in less than 1 min. MR angiograms were interpreted by two observers who had no knowledge of the findings on digital subtraction angiography. A diagnosis of pulmonary emboli was made when MR angiograms showed a constant intraluminal filling defect or an abrupt vascular cutoff. RESULTS: All thrombi in the proximal branches of the pulmonary arteries were visualized on MR angiograms (n = 13), whereas none of the thrombi in the distal part of the pulmonary arteries were seen (n = 6). In the 11 patients in whom no pulmonary emboli were shown by digital subtraction angiography, findings on MR angiograms were normal (sensitivity, 0.7; specificity, 1.0). CONCLUSION: Our results suggest that dynamic contrast-enhanced MR angiography is an accurate method for detecting emboli in the proximal portions of the pulmonary arteries but is of no value in detecting peripheral emboli.

Angiography, Digital Subtraction↗

PubMed2002

[Surgical management of anterior communicating artery aneurysms based on computed tomographic angiography with three-dimensional reconstruction and without preoperative angiography].

OBJECTIVE: To demonstrate the usefulness of threedimensional computed tomographic angiography (CT- 3D-angiography) in the microsurgical management of aneurysms of the anterior communicating artery (AComA). MATERIALS AND METHODS: A total of 28 consecutive patients with ruptured aneurysms of the AComA diagnosed by means of CT-3D-angiography and without preoperative angiography were operated on. The findings of the CT-3D-angiography, microsurgical exploration and clínical data were evaluated. RESULTS: There were no false positive findings nor false negative findings in the diagnosis of the AComA aneurysms. The global sensibility of the examination was 87.9%. The CT-3D-angiography study shows a left A1 segment dominance in 53.6% of cases, a right A1 dominance in 14.3% of cases and both A1 segments of the same diameter in 32.1%. Aneurysms growing on the traject of the AComA were associated with both A1 segments of the similar diameter and an AComA traject pararell to the transverse plane. Aneurysms implanted on the A1-A2 junction were associated with a dominant homolateral A1 segment and an oblique AComA traject. Microsurgical management of the lesions was done a mean of 3.7 days after bleeding. CONCLUSION: The study of patients with acute subarachnoid hemorrhage with CT-3D-angiography allows a reliable diagnosis of AComA aneurysms. The examination gives some anatomical data that allow the study of the hemodinamic changes involved in the development of the aneurysms. Moreover, provides usefull information for the microsurgical clipping. CT-3D-angiography allows to improve some health indicators but its impact in the final result of the patients needs more clinical data.

Adult↗

PubMedDate not supplied

Diagnosis of carotid artery stenosis: comparison of 2DFT time-of-flight MR angiography with contrast angiography in 50 patients.

Fifty patients underwent 2DFT time-of-flight MR angiography and intraarterial contrast angiography for evaluation of possible carotid atherosclerotic disease. The MR angiography technique employed contiguous axial flow-sensitive (short TR/TE) slices that were reformatted and postprocessed by using a maximum-intensity projection algorithm to provide 16 angiographic views of the carotid arteries. Both studies were independently reviewed by two observers in a blinded manner. Carotid arteries were categorized as normal, mildly stenotic, moderately stenotic, severely stenotic, or occluded. For the 94 carotid arteries available for review, one observer reported a 70% agreement between the two techniques and the second observer reported a 56% agreement (p = .0001). The best correlation was in the severely stenotic category and the worst was in the occluded category. Agreement between observers was 67% for MR angiography and 72% for contrast angiography, which was similar to that between the two techniques. Although not all carotid atherosclerotic disease was visualized equally well, 2DFT time-of-flight MR angiography had a good overall correlation with the "gold standard" of intraarterial contrast angiography, supporting its use as a screening technique. While further improvements are needed, use of MR angiography as the primary diagnostic tool for many patients with suspected carotid stenosis should continue to increase.

Aged↗

PubMed1999

Evaluation of cerebral aneurysms with high-resolution MR angiography using a section-interpolation technique: correlation with digital subtraction angiography.

BACKGROUND AND PURPOSE: The objective was to evaluate the results of high-resolution, fast-speed, section-interpolation MR angiography and digital subtraction angiography (DSA), thereby examining the potential use of a primary noninvasive screening test for intracranial aneurysms. METHODS: The images were obtained in 39 cerebral aneurysmal lesions from 30 patients with a time-of-flight MR angiographic technique using a 1.5-T superconducting MR system. The total image volume was divided into four slabs, with 48 partitions each. To save time, only 24 phase-encoded steps were measured and interpolated to 48. The parameters used included 30/6.4 (TR/TE), a flip angle of 25 degrees , a 160x512 matrix, a field of view of 150x200, 7 minutes 42 seconds of scan time, an effective thickness of 0.7 mm, and an entire thickness of 102.2 mm. Maximum intensity projection was used for the image analysis, and a multiplanar reconstruction technique was used for patients with intracranial aneurysms. RESULTS: Among 39 intracranial aneurysmal lesions in 30 patients, 21 were ruptured and 18 were unruptured. Twelve lesions were less than 2 mm in size, 12 were 3 to 5 mm, 12 were 6 to 9 mm, and three were larger than 10 mm. At initial examinations, 38 of 39 aneurysmal lesions were detected by both MR angiography and DSA, with 97% sensitivity. In confirming aneurysms in neck and parent vessels, multiplanar reconstruction was successful in detecting all 39 aneurysms, whereas MR angiography was successful in detecting 27 (69%) and DSA was successful in detecting 32 (82%) of the lesions. CONCLUSION: High-resolution MR angiography with a section-interpolation technique showed equal results to those of DSA for the detection of intracranial aneurysms and may be used as a primary noninvasive screening test. In the evaluation of aneurysms in neck and parent vessels, the concurrent use of MR angiography and multiplanar reconstruction was far superior to the use of either MR angiography or DSA alone.

Adult↗

PubMed2003

Preoperative evaluation of hilar cholangiocarcinoma with contrast-enhanced three-dimensional fast imaging with steady-state precession magnetic resonance angiography: comparison with intraarterial digital subtraction angiography.

We sought to evaluate the image quality of double-dose, contrast-enhanced 3D fast imaging with steady-state precession (FISP) magnetic resonance (MR) angiography in patients with hilar cholangiocarcinoma, and to compare its efficacy with intraarterial digital subtraction angiography (DSA). Thirty-six patients were studied to determine the visibility of the hepatic artery and portal vein with contrast-enhanced MR angiography. Determination of hepatic arterial and/or portal invasion from cholangiocarcinoma was compared between MR angiography and DSA as well. 0.2 mmol/kg gadolinium chelates were administrated at a rate of 4 ml/s. The hepatic artery was diagnostically visible in 28 patients (78%); the portal vein, in 34 patients (94%). The sensitivities, specificities, and accuracies in distinguishing arterial invasion, were 58%, 93%, and 89%, respectively, with MR angiography; 75%, 99%, and 96%, respectively, with DSA. In distinguishing portal venous invasion, these were 78%, 91%, and 89%, respectively, with MR angiography; 78%, 92%, and 90%, respectively, with DSA. There were no significant differences between imaging methods ( p >.05); however, DSA was superior in specificity regarding hepatic arterial invasion ( p =.0143). The data presented here indicate that noninvasive contrast-enhanced 3D FISP MR angiography has the potential to replace DSA in the preoperative evaluation of hilar cholangiocarcinoma.

Adult↗

PubMed2002

Comparison of contrast-enhanced magnetic resonance angiography and conventional pulmonary angiography for the diagnosis of pulmonary embolism: a prospective study.

BACKGROUND: Diagnostic strategies for pulmonary embolism are complex and consist of non-invasive diagnostic tests done to avoid conventional pulmonary angiography as much as possible. We aimed to assess the diagnostic accuracy of magnetic resonance angiography (MRA) for the diagnosis of pulmonary embolism, using conventional pulmonary angiography as a reference method. METHODS: In a prospective study, we enrolled 141 patients with suspected pulmonary embolism and an abnormal perfusion scan. Patients underwent MRA before conventional pulmonary angiography. Two reviewers, masked with respect to the results of conventional pulmonary angiography, assessed MRA images independently. Statistical analyses used chi(2) and 95% CI. FINDINGS: MRA was contraindicated in 13 patients (9%), and images were not interpretable in eight (6%). MRA was done in two patients in whom conventional pulmonary angiography was contraindicated. Thus, MRA and conventional pulmonary angiography results were available in 118 patients (84%). Prevalence of pulmonary embolism was 30%. Images were read independently in 115 patients, and agreement obtained in 105 (91%), kappa=0.75. MRA identified 27 of 35 patients with proven pulmonary embolism (sensitivity 77%, 95% CI 61-90). Sensitivity of MRA for isolated subsegmental, segmental, and central or lobar pulmonary embolism was 40%, 84%, and 100%, respectively (p<0.01 for isolated subsegmental vs segmental or larger pulmonary embolism). However, subgroups contained small numbers. MRA identified pulmonary embolism in two patients with normal angiogram (98%, 92-100). INTERPRETATION: MRA is sensitive and specific for segmental or larger pulmonary embolism. Results are similar to those obtained with helical computed tomography, but MRA has safer contrast agents and does not involve ionising radiation. MRA could become part of the diagnostic strategy for pulmonary embolism.

Adolescent↗

PubMed1995

[CT angiography in carotid stenosis. Diagnostic value compared to color-coded duplex ultrasonography and MR angiography].

PURPOSE: To evaluate the accuracy of different diagnostic methods for the visualization of the carotid arteries and their pathological changes in order to avoid invasive angiography whenever surgery was considered. MATERIAL AND METHODS: 24 patients with clinically suspected stenosis or occlusion of the carotid arteries were prospectively examined via CT angiography. MR angiography and colour-coded duplex sonography (ccds) to evaluate the degree of stenosis and the extent of calcification. RESULTS: In 36 cases stenoses of different extent could be documented with CT angiography, 33 cases were found using colour-coded duplex sonography and MRA. Sonography could not prove mild stenoses (< 30%), and in two patients with sonographically suspected total occlusion vessel perfusion was documented via CT angiography. MR angiography led to a overestimation in patients with high-grade stenosis compared to the degree of stenosis obtained via ccds and CTA. With regard to the diagnosis of calcification MIP, reconstructions after CT examination showed best correlation to the plain CT slices referring to length (94.6%) and thickness (89.2%). CONCLUSION: CTA with MIP reconstructions is an excellent screening method and, in combination with ccds, CT angiography may replace DSA before surgery or intervention.

Aged↗

PubMed1996

Angiographic detection of gastrointestinal bleeding. An experimental comparison of conventional screen-film angiography and digital subtraction angiography.

RATIONALE AND OBJECTIVES: The authors experimentally assess and compare the detection limit of gastrointestinal bleeding in digital subtraction angiography (DSA) and conventional screen-film angiography. MATERIALS AND METHODS: Arterial blood flow was simulated using a tube model in which bleeding was imitated by exudation of liquid containing contrast material. Gut peristalsis was imitated using silicone tubes filled with air and liquid. Images were acquired by DSA and conventional screen-film angiography. The iodine concentration was increased in increments from 1 mg I/mL, with and without simulated peristalsis, and with both free and circumscribed extravasation of contrast material. RESULTS: The detection limit for free extravasation in DSA was 1 mg I/mL without peristalsis and 60 mg I/mL with peristalsis. The corresponding figures for circumscribed extravasation were 1 mg I/mL and 34 mg I/mL. The detection limit for free extravasation in screen-film angiography was 172 mg I/mL both with and without simulated peristalsis. Circumscribed extravasation was detected at 9 mg I/mL without peristalsis and 7 mg I/mL with peristalsis. CONCLUSION: Digital subtraction angiography is the more sensitive angiographic technique for detection of gastrointestinal bleeding and is superior to conventional screen-film angiography, provided that it is performed with adequate parasym-pathicolysis and suspended respiration. Only when these requirements cannot be achieved is screen-film angiography advantageous.

Angiography↗

PubMed2005

3-D magnetic resonance angiography versus conventional angiography in peripheral arterial disease: pilot study.

BACKGROUND: Angiography is usually performed as the preoperative road map for those requiring revascularization for lower extremity peripheral arterial disease (PAD). The alternative investigations are ultrasound, 3-D magnetic resonance angiography (3-D MRA) and computed tomography angiography. This pilot study aimed to assess whether 3-D MRA could replace the gold standard angiography in preoperative planning. METHODS: Eight patients considered for aortoiliac or infrainguinal arterial bypass surgery were recruited. All underwent both imaging modalities within 7 days. A vascular surgeon and a radiologist each reported on the images from both the 3-D MRA and the angiography, with blinding to patient details and each others reports. Comparisons were made between the reports for the angiographic and the 3-D MRA images, and between the reports of the vascular surgeon and the radiologist. RESULTS: Compared to the gold standard angiogram, 3-D MRA had a sensitivity of 77% and specificity of 94% in detecting occlusion, and a sensitivity of 72% and specificity of 90% in differentiating high grade (>50%) versus low grade (<50%) stenoses. There was an overall concordance of 78% between the two investigations with a range of 62% in the peroneal artery to 94% in the aorta. 3-D MRA showed flow in 23% of cases where conventional angiography showed no flow. CONCLUSIONS: In the present pilot study, 3-D MRA had reasonable concordance with the gold standard angiography, depending on the level of the lesion. At times it showed vessel flow where occlusion was shown on conventional angiogram. 3-D MRA in peripheral vascular disease is challenging the gold standard, but is inconsistent at present.

Aged↗