Digital substraction angiography in the evaluation of intracranial and extracranial vascular disease

Digital subtraction angiography (DSA) is a method of visualizing the vessels of the body with the intravenous injection of contrast material. Improvements in computers, television systems, and image intensifiers have contributed to the increased image quality of DSA. With DSA, the vessels such as the carotid bifurcations and the intracranial vasculature can be visualized with a 2–3% concentration of contrast material, while with conventional angiography, the concentration of contrast in vessels is 40–50%. Using IV DSA, visualization of the carotid bifurcations is of good or excellent quality 85% of the time. In a high percentage of these cases, IV DSA replaces conventional angiography, although for imaging of the intracranial vessels, IV DSA is not as good as conventional angiography. In most tumor patients, however, conventional intracranial angiography is not needed because IV DSA combined with computed tomography gives sufficient information.     

Intraarterial digital subtraction angiography: A comparative view

Intraarterial digital subtraction angiography (IA DSA) was performed in 122 patients undergoing a variety of diagnostic and interventional angiographic procedures. Owing to the increased contrast resolution of DSA, diluted contrast material in concentrations of from 12-19% could be employed, thereby significantly reducing contrast material doses compared to doses used with conventional film-screen angiography or intravenous DSA. Patient discomfort was convincingly reduced due to the injection of dilute contrast material. Subtracted digital images could be viewed immediately on a cathode ray tube (CRT) resulting in faster procedures with less catheter time. Savings in film costs relative to conventional angiography were also achieved.     

Peripheral vascular disease: prospective study of intraarterial digital subtraction angiography using a 9-inch intensifier

A prospective randomized study was undertaken to evaluate the role of intraarterial digital subtraction angiography (IADSA) in the study of peripheral vascular disease. Patients underwent either conventional film-based angiography alone, digital subtraction angiography (DSA) alone, or a combined study. With a 9-inch image intensifier, DSA alone resulted in cost savings of film and contrast material but required a significantly longer examination period than the other groups and an increased iodine dose per examination. When the images were analyzed by a radiologist and a vascular surgeon, the DSA studies provided less detail in the aortoiliac region than the other techniques but had advantages in demonstrating the runoff vessels. IADSA examination should not replace conventional arteriography in patients with peripheral vascular disease but has a useful complementary role.     

Intravenous digital subtraction angiography: peripheral versus central injection of contrast material

Central and peripheral intravenous injections of contrast material for digital subtraction angiography were compared in 30 patients. With 40 ml of contrast material, visualization of the carotid bifurcations was as good with the peripheral as with the central injection. A more consistently high-quality examination of the small intracranial vessels was obtained with the central injection.     

Comparison of intravenous digital subtraction angiography to conventional aortography in patients with abdominal aortic aneurysm

Evaluation of intravenous digital subtraction angiography (IV DSA) in patients with abdominal aortic aneurysm was performed by obtaining catheter aortograms immediately before DSA studies in ten patients. Diagnostic images were obtained in nine of ten digital subtraction examinations. Although repeat injections were necessary in six DSA and three conventional aortography cases for adequate imaging of both cephalad and caudal extension of the aneurysm, average contrast dose was 53 cc (62 cc in standard catheter studies). Renal artery stenosis was diagnosed by DSA in two of three vessels, multiple renal arteries were demonstrated by both modalities in two cases. Digital subtraction and conventional aortographic findings were proved at surgery. Intravenous DSA was shown to be useful in the preoperative evaluation of patients with abdominal aortic aneurysm. This work was supported in part by U.S. Public Health Service Grant No. HL07334.     

Digital subtraction angiography of the extremities using table translation

Digital subtraction angiography (DSA) of the extremities has been performed with both intravenous and intraarterial injections of contrast material. Intravenous studies are usually site specific and are limited by contrast material load; a complete intraarterial study with multiple injections of contrast material may be time consuming. A feasibility study to evaluate a DSA technique that would allow table translation and imaging of two contiguous regions following a single injection of contrast material--bolus-chase DSA--was performed. Forty-five examinations were performed, 13 intravenously and 32 intraarterially. Twelve intravenous and 16 intraarterial DSA examinations were totally satisfactory. Inadequate studies were predominantly caused by slow arterial clearance of contrast material in the distal calf and by operator error. Compared with conventional DSA, anatomic studies of lower-extremity vessels could be obtained faster and with lower contrast material loads using bolus-chase DSA.     

Digital intraarterial subtraction technique of the extracerebral vascular system

We report the results from intraarterial digital subtraction angiography (IA DSA) of the extracerebral vessels with aortic arch injection of contrast medium via femoro-arterial puncture, instead of the more widely used intravenous digital subtraction angiography (IV DSA). Intraarterial DSA is performed using a lower contrast dose and rate, making this study less invasive and costly than the conventional arteriographic study of the aortic arch. Intraarterial DSA provides better resolution than IV DSA. The diagnostic accuracy is almost equivalent to conventional angiography and is largely superior to photographic subtraction angiography with intravenous injection of contrast media.     

Digital subtraction angiography for leg venography.

Venography was performed in 25 legs of 17 patients using digital subtraction angiography (DSA). Reliable diagnoses of deep vein thrombosis or patency were made in the majority of these cases. There were no complications. Multiple injections of contrast material were required to image the entire leg; however, the total quantity of iodine necessary for each leg averaged 9 g, significantly less than with conventional techniques. The preferred method consisted of injecting 15 ml of 100 mg iodine/ml contrast material followed by 15 ml of heparinized saline. DSA proved a safe and useful means of evaluating veins of the leg.     

二氧化碳数字减影血管造影技术现状及临床应用

目的：评价二氧化碳数字减影血管造影技术（ＣＯ２－ＤＳＡ）在临床上的应用和效果。材料和方法：对８５例患者行ＣＯ２－ＤＳＡ，包括肝、肾、脾、肠系膜上动脉造造影７５例，腹主及四肢动脉造影３例直接门静脉造影６例，肝静脉造影１例。采用与气体造影相适应注射方法、投照条件及后处理方法以取得较好困难，同时行碘剂造影对照。结果：ＣＯ２－ＤＳＡ可较好显示靶血管的主干及１、２级分支，且可引导介入插管，尽管对细微结构对照     

Tomographic digital subtraction angiography: initial clinical studies using tomosynthesis. Work in progress

We have developed a method for acquiring multiple tomographic subtraction images using a rapid, repetitive, circular tomographic motion. The method combines the principles of digital subtraction angiography (DSA) and electronic tomosynthesis. Fifteen patients were examined with the technique using single intravenous bolus injections of contrast material. The image sequence obtained during each injection was first processed with a nontomographic mask subtraction, and the result was then compared with the tomographic DSA scans synthesized from the same sequence. The effective section thickness was approximately 0.5 cm, with each section being 0.5-1.0 cm apart. Twelve of the intravenous DSA scans provided the necessary diagnostic or clinically useful information. Two of the three nondiagnostic scans were caused by avoidable technical reasons. In eight cases, the tomographic DSA scans were superior in quality to the nontomographic scans, exhibited significantly less artifact from patient motion and overlying bowel gas, and were effective in separating overlapping vessels. Tomosynthesis permits multiple electronic imaging of the area of interest without reinjection of contrast material and appears to be more informative than nontomographic intravenous DSA imaging.     

Nonselective digital subtraction angiography. Compact contrast material bolus for improved image quality

Digital subtraction angiography (DSA) examinations of major aortic branch vessels traditionally have been performed with aortic injections of dilute contrast material (70-150 mg I/mL) over approximately 2 seconds. This study examines a technique employing rapid boluses of undiluted contrast material (282-300 mg I/mL) in small volumes and compares the quality of the images to those obtained using conventional methods. Twenty intra-aortic DSA angiograms of the renal arteries were performed in 10 patients. In each patient, both compact bolus and conventional injections were performed. Injections of 12 or 15 mL of diatrizoate meglumine-60% at 30 mL/second (duration = 0.4 or 0.5 seconds) were compared with injections of 24 or 30 mL of diatrizoate meglumine-30% at 12 mL/second (duration = 2 seconds). Aside from injection technique and image projection, no other variables were altered, and the iodine loads were the same for the two injections in each patient. The images were paired and rated by four radiologists without knowledge of the technical parameters. The radiologists overwhelmingly preferred the images corresponding to the compact bolus technique (Chi-square analysis P less than .001). Visualization of the main renal arteries and the intrarenal branches was improved (P less than .001 for both). A reduction in misregistration artifact is suggested but not statistically significant. We conclude that image quality in nonselective, intra-arterial DSA can be improved without an increase in iodine dosage by the rapid administration of undiluted contrast material in small volumes.     

DSA in acute gastrointestinal hemorrhage: clinical and in vitro studies

Selective intraarterial digital subtraction angiography (DSA) was used to examine 37 patients with acute gastrointestinal (GI) tract bleeding. Conventional screen-film angiography was used as an adjunct to DSA when a larger field of view was needed (five patients) and when bowel motion prevented the acquisition of adequate image quality with DSA (two patients). Conventional angiography was also performed in all cases in which there were negative DSA examinations. DSA reduced the mean examination time considerably (20% reduction overall), especially for cases involving embolization therapy (35% reduction). DSA was especially valuable in the upper GI tract, where it was used to rapidly locate and/or assist in the embolization of bleeding sites in 19 of 20 patients with positive angiograms. There were 12 true-negative DSA examinations and one false-negative examination due to the limited field of view (9 inches [22.9 cm]). Bowel and respiratory motion were not important problems in the upper GI tract. In the lower GI tract, the usefulness of DSA was severely limited by the small field of view and the misregistration artifact caused by bowel motion. In an in vitro study, DSA and conventional angiography were compared as to their ability to depict several rates of extravasation of contrast material in a model of GI bleeding. DSA tended to be more sensitive for the detection of simulated extravasation (P less than .07).     

Intraarterial digital subtraction angiography in diagnostic arteriography

Intraarterial digital subtraction angiography (DSA) was performed in 133 diagnostic arteriographic procedures during a 10-month period. The increased contrast resolution of DSA permitted the use of a dilute (15%) contrast material. A significant reduction in contrast material dose compared with conventional film-screen arteriography and intravenous DSA was thus achieved. This was especially advantageous in patients with diminished renal function. The dilute contrast material also resulted in less patient discomfort. Subtracted images were available immediately on cathode ray tube display, resulting in faster procedures, and a considerable saving in film cost compared with conventional arteriography. It is concluded that intraarterial DSA is a useful technique that may replace conventional film-screen arteriography in many applications.     

Intravenous digital subtraction angiography in patients with Aorto-arteritis (Takayasu's)

Aorto-arteritis is one of the commonest vascular diseases in China as well as in Japan and other parts of Asia. The results of digital subtraction angiography (DSA) in 50 patients with aortoarteritis are reported, and the merits and demerits of intravenous (IV) DSA in the diagnosis of this entity are evaluated. Among the 51 studies performed on 50 patients, IV DSA was used in 48, intraarterial (IA) DSA in 3, and good-to-excellent visualization was obtained in 96% of patients. Aorto-arteritis of varying severity and involving the thoraco-abdominal aorta, the iliac arteries, and other major branches was clearly demonstrated by IV DSA. IV DSA, as compared to our previous experience with conventional arteriography in this entity, may be substituted for conventional arteriography in most patients. A large dose of contrast media needed for a complete study is a major deficiency of IV DSA, and it also has limitations for showing the intrarenal arterial branches.     

Computer processed fluoroscopic images for digital intravenous renal angiography

We investigated intravenous digital angiography using computer processed fluoroscopic images. Computer processed fluoroscopy (CPF) was compared to conventional digital subtraction angiography (DSA) in 39 patients referred for renal vessel evaluation. For assessment of CPF the anterior-posterior images were compared with the corresponding digital subtraction angiograms. 79% percent of DSA and 71% of CPF studies were diagnostic. Peripheral injection of contrast medium caused deterioration of CPF images. Skin dose measurements were obtained in 24 patients. The median dose for DSA was 8.2 rad, compared to 1.1 rad for CPF. It is concluded that sophisticated algorithms should be investigated for digital angiography, so that high image quality can be achieved with a reduced radiation exposure.     

Utility of CT angiography and MR angiography for the follow-up of experimental aneurysms treated with stents or Guglielmi detachable coils

BACKGROUND AND PURPOSE: Previous studies have depicted arterial and aneurysmal anatomy with three-dimensional time-of-flight (3D-TOF) MR angiography before and after treatment with Guglielmi detachable coils (GDCs) and with CT angiography before and after treatment with stents and stent-grafts. We investigated the ability of time-resolved contrast-enhanced 3D MR angiography (3D MR digital subtraction angiography [DSA]) to accurately depict the anatomy of experimental lateral aneurysms before and after treatment with GDCs and a variety of stents or stent-grafts, and compared these findings with 3D-TOF MR angiography without and with contrast enhancement and CT angiography. METHODS: Two nitinol stents, two nitinol-polytetrafluoroethylene (PTFE) stent-grafts, and two stainless steel stents were deployed in three dogs with experimental carotid aneurysms. In a fourth animal, one of three aneurysms was completely occluded with GDCs. The other two aneurysms were loosely packed to ensure persistence of some residual aneurysmal lumen. Cut-film angiography, CT angiography, 3D-TOF MR angiography without and with contrast enhancement, and 3D MR DSA were performed in all dogs before and 3 weeks after treatment. RESULTS: 3D MR DSA was superior to conventional 3D-TOF MR angiography without and with contrast enhancement in accurately depicting experimental lateral aneurysms and superior to CT angiography in depicting aneurysms treated by GDCs. 3D MR DSA and CT angiography were comparable in depicting vessels treated with nitinol stents and stent-grafts, whereas CT angiography was superior for showing vessels treated by stainless steel stents. CONCLUSION: We recommend further development and clinical evaluation of 3D MR DSA for imaging cerebral aneurysms before and after treatment with GDCs. 3D MR DSA or CT angiography may be useful for evaluating vessels containing nitinol stents or nitinol-PTFE stent-grafts, whereas CT angiography should be used for follow-up of vessels treated by stainless steel stents.     

Helical CT angiography: dynamic cerebrovascular imaging in children

BACKGROUND AND PURPOSE: The purpose of this study was to assess the feasibility of helical CT cerebrovascular imaging (CTCVI) in children and to make initial comparisons with MR angiography and digital subtraction angiography (DSA). METHODS: Twenty-six patients, ages 3 days to 17 years, were examined with CTCVI. Patients were scanned with 1-mm collimation and 2:1 pitch 30 seconds after the initiation of a hand injection of 2 mL/kg nonionic contrast material (320 mg/dL iodine) with a maximum dose that did not exceed 80 mL (minimum volume, 5 mL in a 2.5-kg infant). Reconstructions were done using maximum intensity projection and integral rendering algorithms. Four patients had CTCVI, MR angiography, and DSA (42 vessels studied) and nine patients had CTCVI and DSA (136 vessels studied). Scores of 1 (not present) to 3 (present in continuity to the first bifurcation) were assigned independently by two radiologists to 32 vessels in each correlated case for each available technique. RESULTS: There were no technical failures. CTCVI depicted 18 thrombosed dural sinuses, three vascular malformations, one intracranial aneurysm, and four tumors. Ninety-five percent of the vessels seen with DSA were also seen with CTCVI. CTCVI identified all vessels seen on MR angiography. CONCLUSION: Helical CTCVI is an effective technique for assessing the intracranial circulation in children. In this initial comparison, CTCVI showed more vascular detail than MR angiography, and had fewer technical limitations.     

New diagnostic modalities in the diagnosis of primary and recurrent giant-cell tumors of bone

Computed tomography (CT) and/or digital subtraction angiography (DSA) were performed on four patients with primary or recurrent giant-cell tumor of bone. In three cases presented, the tumor was examined with CT and had a precontrast attenuation value of about +50 to +65 HU with unequivocal nonhomogeneous contrast enhancement. In both cases in which DSA was used, contrast-medium enhancement could be recorded by DSA that had definitely not been seen with conventional angiography. It is suggested that in the future CT and DSA may replace conventional angiography in the diagnostic workup of giant-cell tumors.     

Limb muscle compression: an alternative technique for intravenous digital subtraction angiography

A simple, muscle-compression technique to introduce a bolus of contrast medium from hand or foot injections for intravenous digital subtraction angiography (DSA) is described. Fifty millilitres of the non-ionic contrast medium iopamidol 300 was used for each projection. In 18 out of the 20 examinations an acceptably diagnostic arteriogram was obtained. It is suggested that the compression technique is a useful alternative for intravenous DSA when conventional venous access is impossible.     

旋转DSA技术及COMPAS功能在血管造影中的应用

目的探讨旋转DSA及COMPAS技术在血管造影中的应用。方法使用GE数字减影机对疑有血管病变的30例进行常规正侧位检查,而后选择合适的技术参数,对18例进行旋转DSA检查。结果18例患者病变血管位置清晰可见。12例脑血管造影中,11例避开了对比剂血管影的重叠,1例显示不佳;6例肝、肾动脉造影均清晰显示狭窄位置。结论旋转DSA技术及COMPAS功能能显示大多数特殊复杂病变血管并能辅助定位,是常规DSA的重要补充,对病变的诊断及治疗有很大价值。