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PubMed2003

Follow-up of intracranial aneurysms treated with detachable coils: comparison of plain radiographs, 3D time-of-flight MRA and digital subtraction angiography.

All patients with aneurysms treated with Guglielmi detachable coils (GDC) are undergo angiography to assess long-term stability of aneurysm exclusion or to show recurrence of the aneurysm sac, which may require further treatment. We prospectively compared the plain-film appearance of the coil-mass, 3D time-of-flight MR angiography (TOF MRA) and digital subtraction angiography (DSA) for the detection of aneurysm recanalisation during follow-up. We studied 60 patients with 74 intracranial aneurysms treated with Guglielmi detachable coils. We used the unsubtracted image of the angiograms performed at the completion of any embolisation procedure and at follow-up as the plain radiographs. Recanalisation was considered if loosening, compaction or reorientation of the coil mass was apparent. TOF MRA was performed to assess the presence and size of a neck remnant. DSA was regarded as the definitive investigation. Comparison of the techniques showed good agreement as regards aneurysm recanalisation. MRA was more accurate than plain radiography and could replace DSA for long term follow- up. The initial follow-up examination should, however, include both modalities. In cases of contraindications or limitations to MRA, the interval between follow-up angiographic examinations could be increased if there is no change in the plain-film coil-mass appearances.

Adult↗
PubMed1993

[Duplex ultrasonography in the study of carotid and vertebral artery stenosis (comparison with intra-arterial digitalized subtraction angiography)].

A prospective comparison was completed between duplex sonography and intraarterial digitalized subtraction angiography of the carotid and vertebral arteries. The sensitivity, specificity and overall accuracy of the duplex ultrasound were evaluated. In 85 patients 169 sides were investigated. The vessels were divided into normal, 1-24%, 25-49%, 50-74%, 75-99% stenosis and occlusion categories. For stenoses of less than 50% in the proximal internal carotid artery, sensitivity and specificity were excellent (95 and 92%), for lesions causing more than 50% stenosis were 87 and 95%, respectively. The overall accuracy for 0-99% stenosis was 93% and for total occlusions increased to 99%. Sensitivity was lesser (49-54%), but the specificity (92-96%) and overall accuracy (85-86%) were good for the evaluation of common and proximal external carotid artery. Our results indicate that duplex scanning is a valuable technique for measurement of patency and direction of blood flow in the vertebral arteries. The conventional duplex ultrasound can be regarded as an accurate, relatively cheap, and nonevasive screening method for stenoses and occlusions of cervical carotid and vertebral arteries of patients with ischaemic cerebrovascular disease.

Adult↗
PubMed1992

Magnetic resonance angiography of intracranial aneurysms: comparison with intra-arterial digital subtraction angiography.

Magnetic resonance angiography (MRA) with flow rephased gradient-echo sequences is a new non-invasive method for vascular imaging. We compared MRA and intra-arterial digital subtraction angiography in 18 patients with intracranial aneurysms to test whether MRA presently provides an alternative to cerebral angiography for the diagnosis of these anomalies. MRA showed 19 of the 22 aneurysms detected (86.4%). However, problems, especially with turbulent or slow flow, resulted in 6 studies (27.3%) with limited and 2 with questionable demonstration of an aneurysm, and 1 false negative study. At present, MRA is definitely inferior to angiography for the demonstration of intracranial aneurysms, due to its lower resolution and other limitations.

Adult↗
PubMed2005

Three-dimensional fusion digital subtraction angiography: new reconstruction algorithm for simultaneous three-dimensional rendering of osseous and vascular information obtained during rotational angiography.

This report describes three-dimensional (3D) fusion digital subtraction angiography (FDSA), a new algorithm for rotational angiography that combines reconstructions of the blood vessels and the osseous frame in a single 3D representation. 3D-FDSA is based on separate reconstructions of the mask and contrast sequences of the rotational acquisition. The two independent 3D data sets (3D-bone and 3D-digital subtraction angiography [DSA]) are fused in a single 3D representation. The algorithm uses a modification of the Feldkamp method that compensates for signal intensity inhomogeneity inherent to the reconstruction of nonsubtracted rotational acquisitions. By separately reconstructing the osseous and vascular information obtained from the rotational angiogram, 3D-FDSA provides optimal angiographic resolution and precise topographic analysis even when the studied vascular tree is in the immediate vicinity of bone.

Algorithms↗
PubMed1987

[Intravenous digital subtraction angiography].

Thanks to its high contrast resolution, intravenous digital subtraction angiography (IV-DSA) makes it possible to examine the arteries after injection of contrast media into a peripheral arm vein. IV-DSA is indicated in patients with clinical suspicion of arterial stenosis, occlusion, aneurysm or anomaly (ascending and descending aorta, aortic arch and its great vessels, and the renal, iliac, femoral and popliteal arteries). In many such patients, IV-DSA successfully replaces intraarterial catheter angiography. The advantages of IV-DSA (with a peripheral injection technique) as compared to conventional angiography, include its non-invasive character, a lower complication rate and less discomfort for the patient. The disadvantages of IV-DSA include poorer image quality due to lower concentration of contrast media in the vessels, reduced spatial resolution and the need for larger volumes of contrast media. The indication for conventional angiography is an inconclusive intravenous study due to motion artifacts and/or poor resolution.

Analog-Digital Conversion↗
PubMedDate not supplied

Digital subtraction angiography in potential live-kidney donors: a study of 1000 cases.

Intravenous digital subtraction angiography (IV-DSA) combined with excretory urography (IVU) were utilized to study the renal anatomy of 1000 potential live-kidney donors. In the entire series, 712 donors (71.2%) had bilateral single renal arteries, whereas 255 (25.5%) had unilateral multiple, 26 (2.6%) had bilateral multiple, and 7 (0.7%) had unilateral hypoplastic or absent renal arteries determined by IV-DSA. Major renal abnormalities that might be potentially significant for safe renal donation were detected in 76 donors (7.6%) by combined IV-DSA and IVU studies. In 10% of the potential donors, intraarterial digital subtraction angiography (IA-DSA) was required because of the equivocal results of IV-DSA. Of the 1000 potential donors, 700 underwent nephrectomy and the number of renal arteries at nephrectomy was compared with both IV-DSA and IA-DSA reports. Analysis of data revealed a sensitivity of 96% vs 95%, a specificity of 57% vs 75% and an overall accuracy 93% vs 90% for IV-DSA and IA-DSA, respectively, both IV-DSA and IA-DSA were accurate enough in identification of single renal arteries. However, the accuracy of IA-DSA was better than that of IV-DSA in visualization of double (84% vs 64%) and triple (66% vs 33%) renal arteries. It is concluded that IV-DSA combined with IVU is an effective technique for the evaluation of potential kidney donors. In cases where IV-DSA is equivocal, we recommend confirming IA-DSA.

Adult↗
PubMed1989

[Visualization of the renal venous system by renal arteriography with digital subtraction angiography].

The purpose of this study was to obtain vivid and precise images of intrarenal venous branching using DSA for renal arteriography. The type of system used was an ADAC DPS-4100C with 70-80 kVp, and 320 mA, 25-50 msec at 6 frames/sec. The duration was 10 sec and the matrix size was 512 X 512. In order to retain clear subtracted images of intrarenal venous branching with minimal noise the three frames were selected on the time-density curve of DSA: 1) a frame on which renal arteries disappear (frame X), 2) the frame with highest renal venous density value as (frame Y), 3) the difference of the nephrogram density between X and Y frames in which only the density of the nephrogram decreases (frame Z). The mask image is the image subtracted by the equation of the weighted averaging method on X and Z frame and is subtracted from the image of Y frame in the final step. By this method, 40 kidneys in 36 patients were studied, and the intrarenal venous branches up to the interlobar vein was clearly demonstrated in 28 of these cases (70%). This method is useful to estimate the extent of intrarenal lesions and detect abnormal renal blood flow compared with conventional temporal subtraction method.

Angiography, Digital Subtraction↗
PubMedDate not supplied

[Digital subtraction angiography with carbon dioxide in severe arterial ischemia and allergy to iodinated compounds].

When in some selected patients, a direct arterial surgery (DAS) procedure or an endoluminal surgery (ES) are required for a chronic arterial ischemia (III or IV degrees), and an arteriography with contrast is absolutely contraindicated (because of severe renal failure without hemodialysis program or a severe congestive heart failure or a hyperthyroidism or a seriously demonstrated hypersensibility against the contrast agents); an angiography by digital subtraction with carbon dioxide (DIVAS-CO2) is indicated. This technique provides good quality images with minimal risks for the patient and an adequate study for ulterior treatment. We report a case of a 67-years-old woman, with diabetes-II, ischemic cardiopathy, arterial hypertension and a demonstrated hypersensibility against the iodide compounds. The patient was admitted because of a chronic ischemia (IV degree) with ischemic ulcerations on some fingers from the left foot. High doses of analgesic drugs were needed. Because the hypersensibility against the iodide compounds, an angiography with CO2 was carried out. The good quality images provided by this technique showed the factibility of a revascularization.

Aged↗
PubMed1989

Internal densitometric gating for digital subtraction angiography.

Motion artifacts create a severe problem in digital subtraction angiography (DSA) studies. Periodic motion can be eliminated by "gating," matching a precontrast mask with a postcontrast image at the same phase position in the cycle. Electrocardiogram (EKG) signals are used in cardiac DSA for this purpose. An alternate method relies on the generation of a density-time curve dependent on the attenuation changes of anatomical motion. A densitometric window placed at an appropriate location records the variation, from which individual images are tagged with phase position information encoded as delay time. Results are similar to the EKG gating method for cardiac DSA when using an appropriate window location. Periodic motion caused by superimposed respiration can be suppressed by tracking diaphragm or other object attenuation changes with the same algorithms. Using these techniques permits the nonarbitrary matching of mask and contrast images without physiologic monitoring. The techniques are straightforward and relatively easy to implement on systems designed for rapid digital imaging.

Angiography↗
PubMedDate not supplied

Routine use of three-dimensional contrast-enhanced moving-table MR angiography in patients with peripheral arterial occlusive disease: comparison with selective digital subtraction angiography.

PURPOSE: To compare the diagnostic accuracy of contrast-enhanced (CE) three-dimensional (3D) moving-table magnetic resonance (MR) angiography with that of selective digital subtraction angiography (DSA) for routine clinical investigation in patients with peripheral arterial occlusive disease. METHODS: Thirty-eight patients underwent CE 3D moving-table MR angiography of the pelvic and peripheral arteries. A commercially available large-field-of-view adapter and a dedicated peripheral vascular phased-array coil were used. MR angiograms were evaluated for grade of arterial stenosis, diagnostic quality, and presence of artifacts. MR imaging results for each patient were compared with those of selective DSA. RESULTS: Two hundred and twenty-six arterial segments in 38 patients were evaluated by both selective DSA and MR angiography. No complications related to MR angiography were observed. There was agreement in stenosis classification in 204 (90.3%) segments; MR angiography overgraded 16 (7%) segments and undergraded 6 (2.7%) segments. Compared with selective DSA, MR angiography provided high sensitivity and specificity and excellent interobserver agreement for detection of severe stenosis (97% and 95%, kappa = 0.9 +/- 0.03) and moderate stenosis (96.5% and 94.3%, kappa = 0.9 +/- 0.03). CONCLUSION: Compared with selective DSA, moving-table MR angiography proved to be an accurate, noninvasive method for evaluation of peripheral arterial occlusive disease and may thus serve as an alternative to DSA in clinical routine.

Aged↗
PubMed1993

Imaging of dialysis access: a review of 67 failing fistulas investigated by intravenous digital subtraction angiography.

We have reviewed 67 failing haemodialysis fistulas imaged by intravenous digital subtraction angiography (IVDSA). Peripheral venous injection of non-ionic contrast was used in all examinations. No complications relating to peripheral injection, contrast dose or fluid load were experienced. Image quality was poor, owing to inadequate vascular opacification, in 1/67. Image quality was excellent (53/67), or good (13/67) in the remaining 66. 56/66 of these examinations were diagnostic. Diagnoses included abnormalities of feeding arteries, anastomoses, draining veins, and central veins. Multiple abnormalities were demonstrated in 10/56 examinations. Conventional arm venography was performed in addition to IVDSA in five cases where venous images were inadequate owing to anastomotic obstruction (3/5) or poor opacification (2/5). 5/66 examinations were non-diagnostic owing to failure to image the central veins where no cause for fistula failure had been demonstrated. A further 5/66 examinations were non-diagnostic owing to failure to obtain oblique projections of the shunt where vascular details was obscured by overlapping vessels. The authors recommended routine imaging of the dialysis shunt in two planes and central venous imaging in all cases. This would have resulted in reduction of the failure rate from 16% to 1.5% in this series. IVDSA using a peripheral injection technique is simple, free from complications, and provides good quality images of both arterial and venous components of the fistula. Images of vessels not directly involved in fistula formation are routinely obtained and aid the planning of fistula revision.

Angiography, Digital Subtraction↗
PubMed1990

Nonselective preoperative digital subtraction angiography of internal mammary arteries.

In preparation for coronary bypass surgery, digital subtraction angiography (DSA) was used to assess the caliber of the left and right internal mammary arteries and to exclude stenoses of their feeding arteries. In 100 patients (86 males, mean age 56 +/- 9 years) DSA was performed with a Siemens Digitron 2 device. A frontal projection was used in 18 patients, and a 10-20 degree right anterior oblique projection was used in 82 patients. The flow was 10 to 25 ml/sec; 20 ml was injected in 45 patients, 30 ml in 41, 40 ml in 5, 50 ml in 8, and 60 ml in 1 patient. Judged on the proximal third, visualization of the left and the right internal mammary artery was good in 80 and 72, fair in 17 and 20, and bad in 3 and 8 arteries, respectively. The diameter (mm) was 2.7 +/- 0.4 (range 1.8-3.4) and 2.7 +/- 0.3 (range 2.0-3.5), and visible length (cm) was 8 +/- 5 (range 1-24) and 9 +/- 4 (range 2-22) for the two arteries, respectively. The 10-20 degree right anterior oblique view separated the left internal mammary artery better from the descending aorta than the frontal view. In more pronounced right anterior oblique views the ascending aorta interfered with the right internal mammary artery. The quality was not different with 20 ml or 30 ml injections. The feeding arteries could not be assessed in 4 patients. One left subclavian artery was found occluded at the orifice. Incidentally, 2 distal right subclavian stenoses and 2 carotid stenoses were detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography, Digital Subtraction↗
PubMed1999

Contrast-enhanced MR angiography (CE MRA) in the study of the carotid stenosis: comparison with digital subtraction angiography (DSA).

PURPOSE: To determine sensitivity, specificity and diagnostic accuracy of contrast-enhanced magnetic resonance angiography (CE MRA) compared to digital subtraction angiography (DSA) in the study of carotid stenosis. METHODS AND MATERIAL: We studied 23 patients with suspected cerebro-vascular insufficiency by carotid stenosis. Diagnostic examinations by means of CE MRA and DSA were carried out within 24 hours of each other. A 1.5 T superconductive magnet (Signa-General Electric) was used for CE MRA. This technique was performed using a fast spoiled gradient echo recalled (SPGR) sequence acquired in coronal plane 13 sec after injection of contrast medium. Imaging parameters were: TR/TE/FA 8 msec/1 msec/60 degrees, matrix 256 x 128, 1 excitation, FOV 18 x 13 cm, 28 slices per slab, slice thickness of 1 mm, acquisition time of 32 sec. The post-processing was performed using maximum intensity projection (MIP) and targeted MIP. For DSA examinations a Politron 1000 VR unit (Siemens) was used. RESULTS: In the identification and quantification of lesions, CE MRA showed values of 100%. In particular, in comparison to DSA, CE MRA was accurate in diagnosing all true negative and positive cases. The location of stenosis evaluated with CE MRA agreed in all cases with DSA. CONCLUSION: In our experience CE MRA proved to be a very valuable technique in diagnosing carotid stenosis, showing the same diagnostic accuracy as DSA. In this way CE MRA appears to be a substantial alternative technique to conventional MRA and other non-invasive diagnostic methods.

Aged↗
PubMed1999

Interobserver variability in the interpretation of renal digital subtraction angiography.

OBJECTIVE: Our purpose was to analyze interobserver variability in the interpretation of renal digital subtraction angiography and to describe the main factors associated with observer discrepancies. MATERIALS AND METHODS: Forty-nine cases of unilateral atheromatous renal artery stenosis of more than 60% were quantified first by local investigators in a multicenter study and then by five other radiologists. Differences between radiologists for the minimum diameter (Dmin), the reference diameter (Dref), and the percentage of stenosis of the renal arteries were analyzed. Interpretations by the local investigators were then compared with the gold standard, defined as the mean for the five radiologists. RESULTS: The average SD for estimation of all renal artery stenoses by all radiologists was 7% for stenosis percentage, 0.5 mm for Dmin, and 0.7 mm for Dref. Main discrepancies occurred more frequently in cases of weakly opacified renal artery stenosis and poststenotic dilatation. The observations of local investigators disagreed by more than two SDs (14%) with the gold standard for 11 of 49 cases (22%). CONCLUSION: The accuracy of digital subtraction angiography in renal artery interpretations is poor because of variations in evaluating both Dmin and Dref. Precise and reproducible methods for quantification of renal artery stenosis are required.

Adult↗
PubMedDate not supplied

Nonlinear geometric warping of the mask image: a new method for reducing misregistration artifacts in digital subtraction angiography.

PURPOSE: Misregistration artifact is the major cause of image degradation in digital subtraction angiography (DSA). The purpose of this study was to evaluate the efficacy of a newly developed nonlinear geometric warping method to reduce misregistration artifact in DSA. METHODS: The processing of the images was carried out on a workstation with a fully automatic computerized program. After making differential images with a lapracian filter, 49 regions of interest (ROIs) were set in the image to be processed. Each ROI of the live image scanned the corresponding ROI of the mask image searching for the best position to match itself. Each pixel of the mask image was shifted individually following the data calculated from the shifts of the ROIs. Five radiologists compared the images produced by the conventional parallel shift technique and those processed with this new method in 16 series of cerebral DSA. RESULTS: In 14 of 16 series (88%), more radiologists judged the images processed with the new method to be better in quality. Small arteries near the skull base and veins of low density were clearly visualized in the images processed by the new method. CONCLUSION: This newly proposed method could be a simple and practical way to automatically reduce misregistration artifacts in DSA.

Angiography, Digital Subtraction↗
PubMed2002

Gadolinium-enhanced digital subtraction angiography of hemodialysis fistulas: a diagnostic and therapeutic approach.

OBJECTIVE: The aim of our study was to evaluate the feasibility, safety, and potential role of the contrast agent gadoterate meglumine for digital subtraction angiography as a single diagnostic procedure or before percutaneous transluminal angioplasty of malfunctioning native dialysis fistulas. MATERIALS AND METHODS: Over a 20-month period, 23 patients (15 women, eight men) with an age range of 42-87 years (mean, 63 years) having end-stage renal insufficiency and with recent hemodialysis fistula surgical placement underwent gadoterate-enhanced digital subtraction angiography with a digital 1024 x 1024 matrix. Opacification was performed on the forearm, arm, and chest with the patient in the supine position using an injection (retrograde, n = 14; anterograde, n = 8; arterial, n = 1) of gadoterate meglumine into the perianastomotic fistula segment at a rate of 3 mL/sec for a total volume ranging from 24 to 32 mL. Percutaneous transluminal angioplasty was performed in three patients and required an additional 8 mL per procedure. Examinations were compared using a 3-step confidence scale and a two-radiologist agreement (Cohen's kappa statistic) for diagnostic and opacification quality. Tolerability was evaluated on the basis of serum creatinine levels and the development of complications. RESULTS: No impairment of renal function was found in the 15 patients who were not treated with hemodialysis. Serum creatinine level change varied from -11.9% to 11.6%. All studies were of diagnostic quality. The presence of stenosis (n = 14) or thrombosis (n = 3) in arteriovenous fistulas was shown with good interobserver agreement (kappa = 0.71-0.80) in relation to opacification quality (kappa = 0.59-0.84). No pain, neurologic complications, or allergiclike reactions occurred. Three percutaneous transluminal angioplasty procedures (brachiocephalic, n = 2; radiocephalic, n = 1) were successfully performed. CONCLUSION: Gadoterate-enhanced digital subtraction angiography is an effective and safe method to assess causes of malfunction of hemodialysis fistulas. It can also be used to plan and perform percutaneous transluminal angioplasty.

Adult↗
PubMed2005

Modified magnetic resonance angiography of the liver using sensitivity encoding in comparison with digital subtraction angiography and CT arterial portography.

BACKGROUND: Over 355 patients have received orthotopic liver transplantation (OLT) at this hospital since 1993. Preoperative imaging studies of both hepatic vessels and parenchyma in these recipients bettered surgical planning or even precluded the necessity of surgery. Here we report our preliminary results of modified magnetic resonance angiography (MRA) using sensitivity encoding (SENSE) through comparative study with conventional digital subtraction angiography (DSA) and CT arterial portography (CTAP). METHODS: Sixteen patients with suspected liver diseases were included in the study. All of them received both dynamic MRI of the liver using SENSE and digital DSA with CTAP within a two-week interval. The four-phase MRA was reconstructed from source images of the coronal dynamic study. The arterial phase of the modified MRA was compared with DSA in the evaluation of hepatic arteries and the portal phase compared with CT portography reconstructed from source images of CTAP. In dynamic study of the liver, a fixed dose (20 ml) of contrast medium and scan timing were used. RESULTS: The main branches and variations of the hepatic arterial system were well shown on the modified MRA, although the marginal branches of hepatic arteries were of poor quality. The figures of portal veins on MRA were as clear as or superior to those of CTAP. In addition, the suprarenal inferior vena cava (IVC) was well demonstrated on MRA and/or non contrast-enhanced coronal balanced fast-field echo (b-FFE) scan sequence in most cases. MRI detected most parenchymal lesions of the liver and hemodynamics of these lesions could be evaluated on source images of the modified MRA. MRI/MRA also serendipitously revealed several extrahepatic disease entities or variations that were not found on DSA/CTAP. CONCLUSIONS: The modified MRA using SENSE is a cost-effective modality of examination for the demonstration of the whole hepatic vascular system. Combined with MRI, it has the potential as a one-stop imaging modality in the preoperative evaluation in fields such as OLT.

Aged↗