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At least 271 records · Page 15Linked to original sources

PubMed2000

Quantification of carotid stenoses using 3D morphometer, CT angiography and conventional angiography.

BACKGROUND: The aim of this study is to compare the performances of 3D morphometer (M3D) regarding the quantification of extracranial carotid stenoses with selective 2D conventional angiography (reference technique) and spiral CT scan. METHODS: It is a prospective study, including 15 patients (mean age 75) presenting a symptomatic carotid lesion detected via duplex Doppler to be operated. Patients had to hold their breath for 20 seconds. Twenty-nine carotid bifurcations were studied by means of M3D and 2D conventional angiography (15 patients). Only 10 patients (19 bifurcations) underwent a CT scan. The measures were performed on a visual display unit by measuring the pixels as per the NASCET technique. Diameters (MIP technique) and surfaces (reformated axial slices) were measured. RESULTS: With MIP technique, a good correlation was found 20 times in 29 (69%) (overestimation: n=8/29) between M3D and angiography, but only in 9 of 19 cases (47%) between CT scan and angiography. Unlike with M3D, the slices re-oriented with CT scan gave better correlations: 15 times in 19 (79%). With the CT scan, the measures were impossible 8 times on MIP technique, and twice on reformated slices for calcified tight stenoses. Therefore, the quantification by means of spiral CT scan is easier by planimetry on slices. CONCLUSIONS: The reliability of these 3D explorations regarding quantification remains uncertain. The use of a morphometer, provided that technical adaptations are made, could replace selective sequences in multiple incidences that become accessible in the post-treatment period, with an acquisition field larger than the one of the CT scan.

Aged↗

PubMed2004

[Non-invasive coronary angiography with 16 multidetector-row spiral computed tomography: a comparative study with invasive coronary angiography].

INTRODUCTION AND OBJECTIVES: Non-invasive coronary artery angiography by 16 multidetector-row spiral computed tomography is a novel diagnostic tool whose reliability is still unclear. The aim of our study was to compare this technique with invasive coronary angiography. PATIENTS AND METHOD: A total of 31 selected patients were examined with both angiographic methods. Non-invasive studies were performed with a helical computer tomography system (Toshiba Aquilion 16-slices). A contrast agent was injected into a peripheral vein, and cross-sectional images were reconstructed with a slice thickness of 0.5 mm or 1.0 mm. Findings from both techniques were analyzed according to a predetermined segmented anatomical model of the coronary artery. The detection and relevance of coronary artery lesions were evaluated, and lesions with a reduction in diameter of more than 50% were considered significant. RESULTS: Non-invasive coronary angiography yielded an appropriate assessment in 88.4% of the coronary artery segments. The reasons that prevented correct segment evaluation were extensive coronary calcifications, inappropriate breath-hold, motion artefacts and small vessel size. Sensitivity and specificity for the detection of significant coronary lesions with the non-invasive method were 75% and 91%, respectively. Sensitivity and specificity for individual coronary artery segments were as follows: proximal, 89% and 93%; medial, 87% and 90%; distal, 50% and 90%; and secondary branches, 62% and 92%. CONCLUSIONS: Non-invasive coronary artery angiography with 16 multidetector-row computed tomography is a powerful diagnostic tool, especially for the evaluation of the proximal and medial segments of the major coronary arteries.

Adult↗

PubMed2005

Computed tomographic coronary angiography: an alternative to invasive coronary angiography.

Over the past decade, enormous progress has been made in the technology of computed tomography (CT) imaging. Substantial improvements in spatial resolution, temporal resolution, hardware and software now permit imaging of the entire coronary artery tree within a single breath-hold. Several studies have demonstrated a high sensitivity and specificity for the detection of significant coronary artery stenoses. In addition to imaging of the native coronary arteries, CT angiography may also be used to assess arterial and venous bypass grafts, and to detect the presence and composition of atherosclerotic plaque. Because CT angiography images are acquired with electrocardiogram gating, the data sets permit the assessment of left ventricular function (ejection fraction and regional wall motion), left ventricular volumes and, potentially, myocardial perfusion at no extra cost. The practical advantages of CT angiography (in regard to safety and cost) along with its future anticipated advancements make it an attractive alternative to diagnostic coronary angiography.

Coronary Angiography↗

PubMed1986

[Angiography and digital subtraction angiography].

In pediatrics angiography is a method that is used relatively rarely. During the last few years the introduction of nonionic contrast media has led to considerable progress in the field of conventional angiography since these contrast media are tolerated much better than the ionic ones. Also in the field of catheter techniques the introduction of new catheters has led to considerable progress. The new catheters are characterized by very thin walls and wide lumina which allow a high flow of contrast media. Their use in children has considerably reduced local complications at the puncture site. The introduction of digital subtraction techniques on the one hand made intravenous angiography in pediatric patients possible and on the other hand led to considerable reduction of contrast media as compared to conventional angiography. Motion artifacts, however, cause problems. In interventional radiology, as far as blood vessels are concerned, technical possibilities are the same for children as for adults. Dilatations of blood vessels are the main indications. For embolizations the indications are mainly tumor embolizations and bleeding embolizations.

Adolescent↗

PubMed1995

Carotid bifurcation stenosis: a comparative study between MR angiography and duplex scanning with respect to digital subtraction angiography.

PURPOSE: This study compared sensitivity, specificity and diagnostic accuracy of Echoduplex and Magnetic Resonance Angiography (MRA) in the evaluation of carotid bifurcation stenosis. MATERIAL AND METHODS: Twenty-five patients with clinical signs suggestive for cerebrovascular insufficiency (CVI) were studied with Duplex scan, MRA and Digital Subtraction angiography (DSA). Gold standard was the angiographic examination. RESULTS: on equal value of sensitivity (80.5%), MRA showed 96% specificity versus 81% of Duplex scan, 89.4% diagnostic accuracy versus 80.9% for Duplex scan. As for stenosis over 31%, the value of sensitivity did not change i.e., 80.5%; MRA showed 100% specificity versus 97.1% for Duplex, 91.2% diagnostic accuracy versus 89.1% respectively. These values compared by the test for categorial analysis and correspondence analysis (p < 0.05) did not indicate any statistically significant difference. DISCUSSION: on the basis of our experience and as shown by current literature [2, 12] we can state that both MR-angiography and Duplex scan fail in quantifying correctly carotid stenosis with consequent over- and underestimation [3, 4]. However, they can be considered effective diagnostic procedures in a screening program [12, 16]; they are accurate, safe and accepted by the population. CONCLUSIONS: on the basis of the cost in planning the screening of a population at risk for CVI, Duplex scanning is still to be considered the elective procedure.

Adult↗

PubMed1982

[Vertebral angiography of cerebellar astrocytoma-tumor stain, tumor circulation, CT and angiography in diagnosis (author's transl)].

Twelve cases of cerebellar astrocytoma experienced in the Department of Neurosurgery, Hokkaido University School of Medicine were examined primarily for tumor stain and pathological tumor circulation by angiography. In addition, comparison on neuroradiological findings between cerebellar astrocytoma and hemispheric supratentorial astrocytoma (low-grade) was carried out, and neuroradiological differential diagnosis of cerebellar astrocytoma and cerebellar hemangioblastoma was discussed on the basis of the present results and those which were already reported by other investigations and the authors. The results are as follows: 1) Tumor stain was observed in only one case. A tumor was demonstrated as an avascular mass in the remaining 12 cases. 2) Demonstration of cerebellar astrocytoma as hypovascular or avascular masses was related to their low-grade malignancy in histology and cystic nature in gross appearance, as already pointed out. Furthermore, the present study suggested that mural nodules of cystic lesions should have certain weight and sizes so that they could be demonstrated as tumor stain. 3) Abnormal findings concerning tumor circulation were mostly limited to the cases with tumor stain. Early filling veins were not found in any case. Neither feeding artery nor draining vein was clearly identified in some cases. In addition, the abnormal vessels lacked hypertrophic and tortuous changes. 4) In the supratentorial region, five of the 12 low-grade astrocytoma exhibited abnormal tumor stain and tumor circulation by cerebral angiogram and we think that supratentorial and posterior fossa astrocytoma must usually exhibit different pathological tumor circulation by cerebral angiogram, since each group has distinctive clinical and biological characteristics. 5) CT was performed in 7 of 13 cases. It appeared to be more useful than cerebral angiography in the morphological diagnosis Especially in cystic tumors, CT produced minute information concerning peritumoral edema, enhancement of margin of cystic astrocytoma after intravenous contrast medium, and marginal enhancement with layering in the dependent part of the cyst. 6) Neuroradiological different diagnosis of cerebellar astrocytoma and cerebellar hemangioblastoma by CT was difficult in our cases of cystic tumors. However, both tumors were differentiated from each other with ease by tumor stain and tumor circulation in cerebral angiography, since cerebellar astrocytoma was lacking in abnormal vessels, whereas cerebellar hemangioblastoma was marked by many abnormal vessels. Thus, we concluded that cerebral angiography is superior to CT in differential diagnosis between cerebellar astrocytoma and cerebellar hemangioblastoma.

Astrocytoma↗

PubMed1995

Transcranial color-coded duplex sonography, magnetic resonance angiography, and computed tomography angiography: methods, applications, advantages, and limitations.

Transcranial color-coded duplex sonography (TCCD), magnetic resonance angiography (MRA), and computed tomography angiography (CTA) are novel noninvasive or minimally invasive techniques for the study of the intracranial circulation. TCCD is relatively inexpensive and permits bedside examination. It improves the accuracy and reliability of conventional transcranial Doppler studies. The main limitation of TCCD are the ultrasonic windows. They restrict the area of insonation to the major cerebral arteries and the proximal part of its branches, lower the spatial resolution, and may prevent transtemporal insonation. Using MRA, both large and small intracranial arteries and veins can be imaged by selecting the appropriate imaging parameters. MRA provides morphologic information about the cerebral vessels, relying on blood flow as the physical basis for generating contrast between stationary tissues and moving spins. MRA is highly sensitive for the detection of occlusive disease in large intracranial arteries. However, with bright blood techniques the degree of stenosis tends to be exaggerated. Flow direction, eg, in collaterals, can be determined by selective or phase-contrast MRA. Perfusion imaging techniques provide information about blood flow at the capillary level. Diffusion imaging depicts molecular motion. TCCD and MRA used in combination or alone may eliminate the need for intra-arterial digital subtraction angiography (DSA) in most patients studied for occlusive cerebrovascular disease. DSA may be reserved for those patients where there is disagreement among the noninvasive techniques, and for the diagnosis of cerebral aneurysms and arteriovenous malformations. CTA relies on spiral CT technology and intravenous contrast injection. To date, intracranial use has been predominantly for the diagnosis of aneurysms. The role of CTA for the detection of nonaneurysmal intracranial vascular disease has yet to be established.

Adult↗

PubMed2006

Coronary CT angiography and MR angiography of Kawasaki disease.

Although the incidence of coronary artery aneurysms has diminished in patients with Kawasaki disease, coronary artery involvement is still regarded as a major complication of the disease, significantly affecting morbidity and mortality. Recent technical advances in coronary CT angiography (CTA) and MR angiography (MRA) have led to the possibility of using these two imaging methods as minimally invasive alternatives to the more invasive diagnostic catheter angiography in evaluating coronary artery abnormalities, such as aneurysm, stenosis, and occlusion. In this article, we describe imaging techniques and findings of coronary CTA and MRA in Kawasaki disease.

Adolescent↗

PubMed2003

Contrast-enhanced MR angiography vs intra-arterial digital subtraction angiography for carotid imaging: activity-based cost analysis.

The aim of this study was to compare the costs of performing contrast-enhanced MR angiography (CE MRA) with intra-arterial digital subtraction angiography (DSA) for the evaluation of carotid atherosclerotic disease. Activity-based cost analysis was used to identify the costs of performing each procedure. The variable direct costs of performing CE MRA and DSA were determined in 20 patients by using detailed time and motion studies. All personnel directly involved in the cases were tracked to the nearest minute and all consumable items used were recorded. Moreover, procedure times were prospectively recorded for an additional 80 patients who underwent both DSA and CE MRA. The variable direct costs of bed usage in the angiography day-case unit, all direct fixed costs as well as indirect costs were assessed from hospital and departmental accounting records. Total costs for each procedure were calculated and compared using Wilcoxon signed-rank sum test. Mean aggregate costs were Euro 721 for DSA and Euro 306 for CE MRA, resulting in potential savings of Euro 415 per patient (p<0.0001). On average, a DSA procedure thus cost approximately 2.4 (95% confidence intervals: 2.2-2.6) times more than CE MRA to our medical institution. Sensitivity analyses confirmed the robustness of our conclusions across wide ranges of plausible values for various parameters. Assuming equal diagnostic performance, institutions may have substantial cost savings if CE MRA is used instead of DSA for carotid imaging.

Aged↗

PubMed1999

Comparison of digital subtraction angiography with gadolinium-enhanced magnetic resonance angiography in the diagnosis of renal artery stenosis.

Renal artery stenosis (RAS) is a treatable cause of hypertension and renal failure for which no ideal screening technique is currently available. We evaluated the use of dynamic gadolinium-enhanced magnetic resonance angiography (MRA) for the diagnosis of RAS. Sixty-two patients with secondary hypertension were enrolled in the study. All patients had conventional renal angiography and gadolinium enhanced MRA. The sequence used was a 3D FMP SPGR sequence with the following parameters (TR: 26 ms, TE: 6.9 ms, flip angle 40 degrees, field of view 36 x 36 cm, matrix 246 x 256, 1 excitation). Gadolinium 0.3 mmol/kg was administered and 60 1. 5-mm-thick partitions were obtained over a duration of 3.5 min. The MRA images were then compared with conventional digital subtraction angiography (DSA) images. Conventional DSA demonstrated 138 renal arteries, whereas gadolinium-enhanced MRA demonstrated 129 (93 %). Twenty-one renal artery stenoses and four occluded arteries were seen at conventional DSA. Gadolinium-enhanced MRA had a sensitivity of 88 %, specificity of 98 %, accuracy of 96 %, positive predictive value of 92 % and negative predictive value of 97 % when compared with conventional DSA. Gadolinium-enhanced MRA is an accurate technique for identifying patients with RAS. It is less sensitive in picking up accessory renal arteries.

Angiography, Digital Subtraction↗

PubMed1998

Determination of 60% or greater carotid stenosis: a prospective comparison of magnetic resonance angiography and duplex ultrasound with conventional angiography.

The morbidity and cost of conventional angiography (CA) have focused recent efforts in cerebrovascular imaging upon the exclusive use of noninvasive techniques. Our purpose was to prospectively evaluate carotid magnetic resonance angiography (MRA) and to compare its accuracy with color-flow duplex (CFD). Fifty patients were prospectively evaluated with CA and MRA after clinical and CFD findings indicated the need for carotid angiography. CFD measurements of peak systolic velocity (PSV) and end-diastolic velocity (EDV) were made. MRA results were categorized as 0%-39%, 40%-59%, 60%-79%, or 80%-99% stenosis or occluded. Determination of percent carotid stenosis by CA was made as in the North American Symptomatic Carotid Endarterectomy Trial (NASCET). Using receiver operating characteristic (ROC) curves, the probability of correctly predicting a > or =60% stenosis using various CFD thresholds and MRA was assessed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in determining > or =60% stenosis were estimated. For MRA the sensitivity was 85% (95% Confidence Interval [CI] = 69%-94%), specificity 70% (CI = 56%-81 %), PPV 68% (CI = 53%-80%), and NPV 86% (CI = 72%-94%). For CFD the sensitivity was 89% (CI = 74%-96%), specificity 93% (CI = 82%-98%), PPV 89% (CI = 74%-96%), and NPV 93% (CI = 82%-98%). When MRA and CFD results were concordant (n = 64), the sensitivity was 100% (CI = 89%-100%), specificity 95% (CI = 81%-99%), PPV 94% (CI = 77%-99%), and the NPV was 100% (CI = 92%-100%). The area under the ROC curve for CFD was 95%, compared to 83% for MRA (p = 0.0005). We conclude that the low specificity of MRA precludes its use as the definitive imaging modality for carotid stenosis. The 93% specificity of CFD alone warrants its consideration as a definitive carotid imaging study. By ROC curve analysis, CFD offers superior accuracy to MRA. Our data support noninvasive preoperative carotid imaging for detecting a threshold stenosis of > or =60% whether CFD is used alone, or in combination with the selective use of MRA.

Aged↗

PubMed1995

Diagnostic performance of digital subtraction angiography (DSA) and magnetic resonance angiography (MRA): preliminary results in vascular occlusive disease of the abdominal and lower-extremity arteries.

Fifty-nine patients with occlusive disease of the aorto-iliac and femoro-popliteal arteries were investigated prospectively by intravenous (IV) or intraarterial (IA) digital subtraction angiography (DSA) and magnetic resonance angiography (MRA). This was accomplished using a two-dimensional (2D) Inflow- (59 patients) and a 2D Phase Contrast- (RSE--rapid sequential excitation) sequence (29 patients). The spectrum of pathology included stenoses < 50%, stenoses 50-89%, stenoses 90-99%, occlusions, aneurysms and status following reconstructive surgery. MRA- and DSA-examinations were evaluated by four radiologists. The diagnoses were made by consent decisions of a radiologist and a vascular surgeon based on clinical and radiological findings. Diagnostic performance of IA-DSA was superior to all other imaging modalities. Vascular delineation of 2D Inflow-MRA was comparable to that of IV-DSA. The image quality of RSE-MRA was not adequate for diagnosis. In conclusion, 2D Inflow-MRA is a promising method for evaluating abdominal and peripheral arteriosclerotic disease. Interpretation of MR-angiograms, however, requires profound knowledge of MRA-techniques, X-ray angiography and hemodynamics.

Adult↗

PubMed2001

Comparison of three-dimensional contrast-enhanced magnetic resonance angiography and axial radiographic angiography for diagnosing congenital stenoses in small pulmonary arteries.

Accuracy of 3-dimensional contrast-enhanced magnetic resonance angiography (MRA) in diagnosing morphology of the branch pulmonary artery (PA) was evaluated in 73 patients (aged 7.2 +/- 6.4 years [mean +/- SD]) with various congenital heart diseases. The presence or absence of localized stenosis of branch PAs, PA diameter, and Nakata's PA index were determined on MRA and axial radiographic angiography, and the results were compared. Sensitivity, specificity, and overall accuracy in detecting branch PA stenoses were 92.7%, 96.2%, and 95.2%, respectively. Correlations between axial radiographic angiography and MRA were excellent in measuring PA diameter (r = 0.956, SEE = 1.49 mm, n = 139) as well as PA index (r = 0.839, SEE = 48.9, n = 37); both p < 0.0001. Bland-Altman plots showed a mean difference +/- SD for PA diameter of 0.17 +/- 1.51 mm and for PA index of 8.5 +/- 50.1. When the main right and left PAs were taken as the first generation, the most distal branches visible on MRA were the 4.7 +/- 0.7 generation with breath-holding (n = 23) and the 3.7 +/- 0.5 without breath-holding (n = 50), respectively (p < 0.0001). Both intra- and interobserver variabilities of MRA measurements were few (9.5 +/- 11.6% and 13.5 +/- 15.0%, respectively, n = 139). In conclusion, 3-dimensional contrast-enhanced MRA enables us to document branch PA morphology clearly in infants and adult patients with congenital cardiovascular defects.

Adolescent↗

PubMed1997

Directed proximal magnetic resonance coronary angiography compared with conventional contrast coronary angiography.

Magnetic resonance coronary angiography in 36 patients with proximal 1-vessel disease within 1 week of contrast coronary angiography was performed and the time required to complete the study was 13.4 +/- 4.2 min 13.2 +/- 8.1 minutes for the right and left coronary arteries, respectively. The sensitivity, specificity, positive and negative predictive values, and accuracy of magnetic resonance coronary angiography were 100% for right cronary artery disease, and 83%, 98%, 94%, 94%, and 94%, respectively, for left coronary artery disease.

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↗

PubMed1996

Comparison of magnetic resonance angiography with conventional angiography in the detection of intracranial aneurysms in patients presenting with subarachnoid haemorrhage.

Thirty-nine patients admitted with proven subarachnoid haemorrhage were imaged both with 3-D time of flight (TOF) magnetic resonance angiography (MRA) and conventional angiography. As the definitive examination, catheter angiography demonstrated 37 aneurysms; ten patients had no aneurysm, the remaining 29 patients had 37 aneurysms. We found the sensitivity of 3-D TOF MRA for the detection of aneurysms to be 81% and specificity to be 100% when the reporting radiologist inspects not only the MIP reconstructions but also the MRA source data and the axial spin-echo images. The investigation is less accurate if all the available imaging data is not considered.

Adult↗

PubMedDate not supplied

Occlusive arterial disease of abdominal aorta and lower extremities: comparison of helical CT angiography with transcatheter angiography.

The purpose of this study was to evaluate helical CT angiography in the assessment of occlusive arterial disease of abdominal aorta and the lower extremities. Sixteen patients underwent both transcatheter angiography and helical CT. Helical CT was inconclusive in 6.2% of segments whereas angiography was inconclusive in 5%. The overall sensitivity of helical CT was 91% and specificity 93%. Segmental analysis found a sensitivity of 43% in infrapopliteal arteries, and a specificity of 86%.

Aged↗

PubMed1993

Three dimensional time-of-flight magnetic resonance angiography in carotid artery surgery: a comparison with digital subtraction angiography.

Three dimensional time-of-flight magnetic resonance angiography (MRA) and intra-arterial digital subtraction angiography (DSA), considered the gold-standard technique, were compared for pre- and postoperative evaluation of the carotid bifurcation. Images of suitable quality of 194 bifurcations were available with both techniques. Percentage stenosis was graded into 5 groups: A = 0-29%, B = 30-59%, C = 60-89%, D = 90-99%, E = 100% (occlusion). Preoperative MRA (126 bifurcations) overgraded the stenosis in 14 cases and undergraded it in 11. The two techniques agreed in 101 cases and the extent of misgrading was never more than one category. Regression analysis showed a good correlation between the two methods. Severe ulceration was better identified by DSA. As far as the surgical indication was concerned, MRA had a sensitivity of 92.6% and a specificity of 98.3%. In 68 operated cases, postoperative MRA and intraoperative completion angiography showed a satisfactory endarterectomy with no residual stenosis in any of the cases. In conclusion, MRA seems an accurate modality for imaging of carotid bifurcations. Significant limitations still exist for an adequate demonstration of intracranial circulation.

Adult↗