Intracranial vascular stenosis and occlusion: comparison of 3D time-of-flight and 3D phase-contrast MR angiography

We compared the value of 3D time-of-flight (TOF) and phase-contrast (PC) MR angiography (MRA) for detection and grading of intracranial vascular steno-occlusive disease. Unenhanced 3D-TOF MRA and 3D-PC MRA (30–60 cm/s velocity encoding) were performed at the level of the circle of Willis in 18 patients, mean age 56 ± 10 years. Postprocessed images using a maximum-intensity projection reconstruction with multiple targetted projections were analysed. A total of 126 vessels was assessed by PC MRA and 143 by TOF MRA, with digital subtraction angiography (DSA) in 15 patients and/or transcranial Doppler sonography (TCD) in 18 as a standard. Two blinded readers reviewed the MRA, DSA and TCD examinations retrospectively. On DSA and/or TCD the two observers found 32 and 28 steno-occlusive lesions. 3D-TOF MRA was more sensitive than 3D-PC MRA (87 % and 86 % vs. 65 % and 60 %) and had a higher negative predictive value (96 % vs. 89 %). Correct grading of stenoses was achieved in 78 % by 3D-TOF and 65 % by 3D-PC MRA. Received: 24 September 1997 Accepted: 27 February 1998     

Three-dimensional reconstructed rotational digital subtraction angiography in planning treatment of intracranial aneurysms

We evaluated three-dimensional (3D) reconstructions of 200 ° rotational digital subtraction angiography (DSA) images for their contributions to improving the safety of endovascular embolization of intracranial aneurysms. Standard DSA and 200 ° rotational DSA were performed in 40 adult patients (aged 21–77 years) with 45 intracranial aneurysms. Information obtainable from standard DSA and 3D-DSA images about aneurysm shape and size was compared. In 40 (89 %) of the 45 aneurysms 3D-DSA gave additional information about the anatomy of the aneurysm. In 17 (43 %) of these cases aneurysm anatomy could be visualized better on 3D-DSA than on standard DSA images. In three cases only 3D-DSA images showed blood vessels originating from the aneurysm. Reconstructed 3D images were also helpful in visualizing partially clipped aneurysms. On maximum-intensity projection images it was even possible to depict previously embolized aneurysms. Blood vessels originating from the aneurysm are visible on 3D-DSA images, and even previously clipped aneurysms can be visualized well. Rotational DSA with 3D reconstruction is a helpful tool in the assessment of intracranial aneurysms. Received: 7 September 1999; Revised: 26 November 1999; Accepted: 26 November 1999     

Three-dimensional (volume) gradient-echo imaging of the carotid bifurcation: preliminary clinical experience

This study was designed to test the accuracy of magnetic resonance (MR) imaging with a FLASH (fast low-angle shot) 40 degrees volume pulse sequence by comparing it with intraarterial digital subtraction angiography (DSA) in patients with suspected carotid artery stenoses. Fifteen patients referred for evaluation of anterior circulation in cerebrovascular disease composed the pilot group. Twelve patients underwent correlative intraarterial DSA examinations. The FLASH volume sequence, with an echo time of 7.7 seconds, produced high-signal-intensity vascular images for 28 of 30 bifurcations. Of the 24 carotid bifurcations studied with DSA, 22 were depicted with MR angiography. Among the depicted bifurcations, 21 showed good correlation with the DSA images. These included four of four normal bifurcations, three of three with mild stenosis, four of four with moderate stenosis, eight of nine with severe stenosis, and two of two with occlusions. With respect to ulceration, three of four MR angiographic studies showed good correlation with DSA images. This preliminary experience indicates that the method is reproducible and capable of delineating carotid lesions in patients and that it can be performed in conjunction with conventional spin-echo imaging of the brain with only a small increase in patient examination time.     

MRI减影和MR DSA的临床应用

目的评价减影技术用于MRI和MRA的临床意义.材料和方法对65例各部位病灶作T1WIMR增强前后的数字减影,以及27例次各部位病灶作MRDSA.由三位主治医师分别观察和分析减影的效果.结果92例次MRI减影和MRDSA中,减影成功者88例次(95%).三位主治医师的观察结果一致.42例T1WI平扫显示为高信号或为含高信号区域的病灶,其中25例(60%)减影前不能判断有否增强或(和)难以明确增强区域的大小;减影后,全部病灶均能作出明确的判断.27例次MRDSA中24例(90%)在观察细小血管方面明确优于未作减影的MRA.结论MRI减影方便易行而颇有用处.对T1WI高信号病灶的增强与否和增强区域大小的判断帮助很大.MRDSA对细小血管的显示和判断有否肿瘤染色是一种十分重要的技术.     

Digital subtraction angiography in extremity trauma

Digital subtraction angiography (DSA) may have considerable impact on the work-up of patients who have suffered blunt or penetrating trauma. The angiographic evaluation of vascular injuries (e.g., arteriovenous fistulae, pseudoaneurysms, hemorrhage) can be accomplished rapidly and with minimal catheter use and manipulation, which is particularly important for those critically ill patients who have significant immobility because of multiple fractures. We retrospectively reviewed the digital subtraction angiograms in 50 consecutive cases of extremity trauma. The quality of the images in 44 of these permitted a confident diagnosis, the accuracy of which was confirmed by surgical or clinical follow-up. One false-positive and three false-negative examinations for small muscle bleeders were discovered, but none of these was considered clinically significant. DSA reduces the time required to perform the procedure, the amount of contrast material injected, patient discomfort, and film cost. Its major disadvantage is the limited field size of the image intensifier.     

Ureteropelvic junction obstruction: use of helical CT for preoperative assessment--comparison with intraarterial angiography

PURPOSE: To evaluate helical computed tomography (CT) in the preoperative assessment of crossing arteries in kidneys with ureteropelvic junction (UPJ) obstruction and to compare the results with those obtained by means of angiography. MATERIALS AND METHODS: Forty-one consecutive patients with symptomatic UPJ obstruction in 42 obstructed kidneys underwent renal helical CT and renal intraarterial digital subtraction angiography (DSA; flush aortography and bilateral selective renal injections). The helical CT and DSA images were interpreted in a blinded manner by two readers, and the results were compared. RESULTS: DSA showed 126 renal arteries in the 41 patients; 56% of patients had supernumerary renal arteries. Helical CT depicted 121 (96%) of these 126 renal arteries prospectively. Retrospectively, 124 (98%) renal arteries were visible on CT images. Twelve (29%) of the 42 kidneys with UPJ obstruction had identifiable arteries crossing the UPJ on DSA images. If DSA is used as the standard of reference, CT angiography was 100% sensitive and 96.6% specific for depicting these crossing arteries. CONCLUSION: Renal helical CT seems suitable to replace intraarterial DSA in the preoperative assessment of crossing arteries in kidneys with UPJ obstruction.     

Breath-hold 3D gadolinium-enhanced subtraction MRA in the detection of transplant renal artery stenosis.

AIMS: The purpose of this study was to assess the value of breath-hold 3D gadolinium-enhanced subtraction magnetic resonance angiography (GD-MRA) in the detection of transplant renal artery stenosis (TRAS). PATIENTS AND METHODS: Seven patients with suspected post-transplant renal artery stenosis were studied. GD-MRA was performed at 1.5T with a 3D fast spoiled gradient recalled echo (FSPGR) pulse sequence. Before injection of contrast medium, the 3D pulse sequence was performed to obtain a set of non-contrast images for subtraction purposes. Dynamic 3D imaging was performed simultaneously with the bolus injection of 40 ml of gadopentetate dimeglumine. Angiographic images were reconstructed using the Advantage Window workstation (version 2.0 GE Medical Systems) and subtraction was made with the pre-contrast image data. Any signal intensity cut-off or narrowing of more than 50% was regarded as significant stenosis. Ultrasound Doppler (USD) study was performed with both colour and spectral studies. Peak systolic velocity (PSV) of greater than 2.0 m/s and acceleration time (AT) greater than 120ms was regarded as positive for TRAS. These were then compared with the digital subtraction angiography (DSA) as the gold standard. RESULTS: A total of nine examinations performed in seven patients were included in the analysis. MRA correlated with the DSA findings in eight examinations, with one false negative. USG correlated with DSA in six examinations, with two false negative and one false positive case. CONCLUSION: In our opinion, GD-MRA is a promising and non-invasive technique in the detection of TRAS.     

Evaluation of vascular rings with digital subtraction angiography

Seven patients with vascular rings were evaluated over a 2-year period with intravenous digital subtraction angiography (DSA), which was compared with screen-film aortography or cineangiography. The seven patients were also evaluated with barium esophagography. Six of the seven DSA images were totally diagnostic and one study was only partly diagnostic. Six of the seven vascular anomalies were confirmed surgically. DSA is suggested as an alternative to arteriography in evaluating patients with suspected vascular rings.     

Fundamental study of DSA images using gadolinium contrast agent

Most contrast agents used in digital subtraction angiography (DSA) are non-ionic iodinated contrast agents, which can cause severe side effects in patients with contraindications for iodine or allergic reactions to iodine. Therefore, DSA examinations using carbon dioxide gas or examinations done by magnetic resonance imaging (MRI) and ultrasound (US) were carried out in these patients. However, none of these examinations provided images as clear as those of DSA with an iodinated contrast agent. We experienced DSA examination using a gadolinium contrast agent in a patient contraindicated for iodine. The patient had undergone MRI examination with a gadolinium contrast agent previously without side effects. The characteristics of gadolinium and the iodinated contrast agent were compared, and the DSA images obtained clinically using these media were also evaluated. The signal-to-noise (SN) ratio of the gadolinium contrast agent was the highest at tube voltages of 70 to 80 kilovolts and improved slightly when the image intensifier (I.I.) entrance dose was greater than 300 microR (77.4 nC/kg). The dilution ratios of five iodinated contrast agents showed the same S/N value as the undiluted gadolinium contrast agent. Clinically, the images obtained showed a slight decrease in contrast but provided the data necessary to make a diagnosis and made it possible to obtain IVR without any side effects. DSA examinations using a gadolinium contrast agent have some benefit with low risk and are thought to be useful for patients contraindicated for iodine.     

Three-dimensional angiography using rotational digital subtraction angiography: usefulness in transarterial embolization of hepatic tumors

Purpose: To assess the usefulness of three-dimensional (3D) angiography using rotational digital subtraction angiography (DSA) in transarterial embolization of hepatic tumors.

Material and Methods: Thirty-one 3D angiographies were conducted using rotational DSA during abdominal angiography for transarterial embolization of hepatic tumors. The quality of visualization of the tumor and feeder arteries as imaged by 3D angiography versus DSA anterioposterior (AP) images was compared.

Results: 3D rotational angiography provided excellent 3D visualization of the vascular structures of the hepatic artery, and was especially useful in patients with overlapping tumors on DSA AP images and in patients with complex vascular anatomies. Compared to DSA AP images, however, tumor stains could not be detected on 3D-A, but could be detected on DSA in four patients (13%). In 9 patients, feeding arteries could not be detected on 3D-A, but could be detected on DSA (29%).

Conclusion: 3D rotational angiography alone may not be suitable for pre-procedural mapping in transarterial embolization of hepatic tumors, but may be of value when information supplementary to DSA AP images is needed.     

Percutaneous transluminal angioplasty of the renal arteries: intravenous digital subtraction angiography for follow-up

A group of 50 consecutive patients who had undergone successful renal angioplasty two or more years previously was studied by video digital subtraction angiography (DSA). Thirty additional patients were studied by both DSA and conventional catheter arteriography. Among the 30 patients, DSA findings agreed with the arteriographic findings in 87% of the examinations: 92% of the postangioplasty patients had satisfactory DSA examinations. Using DSA two years after angioplasty, we were able to determine a restenosis rate of 22.5% among patients with atherosclerosis and of 0% among patients who had fibromuscular disease. DSA provides a useful method to follow-up renal angioplasty, and it is well accepted by patients.     

A comparison of bolus chasing and static digital subtraction arteriography in peripheral vascular disease

The purpose of this study was to compare the techniques of bolus chasing angiography (BCA) and digital subtraction angiography (DSA). 75 patients with symptomatic atherosclerotic peripheral vascular disease were randomly assigned to have their lower limbs examined by BCA or DSA. Dose-area product (DAP), time of examination and dose of contrast medium were measured. Staff doses were measured with personal electronic dosemeters. Image quality was assessed from the laser printed images. DSA produced better images of vessels below the inguinal ligament, particularly the crural vessels (1/76 vs 17/74 non-diagnostic examinations, p < 0.00001) but at a higher DAP (median 53.8 Gy cm2 vs 18.9 Gy cm2, p < 0.01). Contrast medium dose was higher with BCA (29.8 gI2 vs 25.3 gI2, p < 0.01). Staff doses per unit patient dose were 2.3-3.3 times higher with BCA than DSA. Because of the poor long-term prognosis of patients with peripheral vascular disease, the improved image quality obtained by DSA justifies the increased radiation dose.     

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.     

数字化摄影技术在非血管性介入术中的应用价值

目的　探讨数字化摄影技术在非血管性介入术中的应用价值及其特点。方法　搜集 2 0 4例次非血管性介入造影片 ,其中利用DSA组 12 6例次 ,数字化胃肠组 (CF) 78例次。根据其造影显影情况 ,图像质量 ,按两组进行观察、分析、评估、统计。结果　非血管性介入成像中 ,被检部位管腔充盈满意。管壁显示清楚者 ,DSA组有 10 4例次 ,占本组的 82 %。CF组有 6 6例次 ,占 85 %。对DSA组与CF组进行 χ2 检验 ,χ2 =7.32 6× 10 -4 (P >0 .0 5 )。结论　数字化摄影技术在非血管性介入术中与DSA有类似的图像清晰度。同时 ,在非血管性介入术中不需要快速的大量的连续摄影 ,利用数字化技术 ,用CF机作非血管造影 ,有一定的优越性     

An algorithm for correction of distortion in stereotaxic digital subtraction angiography

An algorithm for correction of the geometrical distortion in digital subtraction angiography (DSA) images was developed. Originally invented for 3D X-ray angiography, the algorithm was implemented in a computer program designed to fulfil the specific needs of stereotaxic DSA. The algorithm is based on transformation of an image of a grid from a distorted image back into its original pattern. The same transformation is then applied pixel-by-pixel to the angiographic images, which are acquired in direct conjunction with the grid image, without moving the gantry. The algorithm was tested in phantom studies and in the clinical situation with seven patients in ten examinations. Comparisons were made between co-ordinate determinations made on conventional full-size cut film and those performed on uncorrected and corrected DSA images, using 30- and 23-cm fields of view. With our method of measurement we could not show any remaining geometric distortion in the corrected DSA images. This distortion correction can, if properly applied, be used for high-precision stereotaxic DSA. Received: 16 September 1995 Accepted: 5 January 1996     

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.     

MR digital subtraction angiography of cerebral arteriovenous malformations

BACKGROUND AND PURPOSE: Although phase-contrast MR angiography provides some information regarding hemodynamics of cerebral arteriovenous malformations (AVMs), most conventional MR angiographic techniques have not been helpful in this respect. We attempted to determine the value of MR digital subtraction angiography (DSA) in assessing AVM hemodynamics. METHODS: We developed an MR DSA technique by combining rapid thick-section T1-weighted imaging with a bolus injection of contrast material. The temporal resolution was 0.56 to 0.61 seconds per scan. MR DSA images obtained from 14 patients with AVMs were reviewed. Anatomic depiction of each component of the AVM was rated using a four-point grading scale (excellent = 3, good = 2, fair = 1, poor = 0) to compare conventional vs MR angiograms. RESULTS: We were able to obtain serial images in which passage of contrast material was evident within the AVM, although the sequence we used allowed images to be obtained in only one projection. The average score for feeders, nidi, and drainers was 1.6, 2.4, and 2.3, respectively, with an overall average of 2.1. CONCLUSION: The spatial resolution of our technique may fall below the level needed for identification of small vascular components of an AVM. Additionally, the limited slab may restrict application of the technique to assessment of large or very small AVMs. MR DSA, however, can show the hemodynamics of AVMs and may serve as a supplement to conventional MR imaging in the diagnosis of cerebral AVMs.     

CO2—DSA的临床应用研究

目的：探索二氧化碳气体作为血管造影剂的临床应用效果。材料方法：对１６例患者行二氧化碳数字减影血管造影（ＣＯ２－ＤＳＡ）。其中肝动脉造影８例，腹主动脉造影１例，股动脉造影２例，直接门静脉造影３例，肾静脉造影２例，并与同一患者碘剂造影比较。结果：在８例肝肿瘤中，ＣＯ２－ＤＳＡ显示肝动脉－门静脉瘘（ＡＰＦ）６例（６／８），而碘剂显示１例（１／８）。ＣＯ２－ＤＳＡ显示肝内小动脉分支及肿瘤染色不如碘造影剂。但腹主动脉造影、股动脉造影和直接门静脉造影图像较满意，且副作用小。结论：ＣＯ２是一种安全的血管造影剂。ＣＯ２－ＤＳＡ可得到准确、有价值的血管图像，且危险性小。它是显示肝ＡＰＦ的可靠方法     

Detection of intracranial aneurysms with 64 channel multidetector row computed tomography: comparison with digital subtraction angiography

PURPOSE: To compare the contribution of 64 channel multidetector row computed tomography angiography (64MDCT-angiography) with digital subtraction angiography (DSA) in the detection of intracranial aneurysms. METHODS AND MATERIALS: Twenty-nine patients (10 males and 19 females, age: 40-84 years; average: 61.9 years) with clinical and imaging findings strongly suggesting the presence of subaracnoid hemorrhage underwent 64MDCT-angiography and DSA with a short interval between the two examinations (less than 12 h-5 days). CT parameters were: 64 mm x 0.5 mm collimation, pitch-0.828 and helical pitch-53. DSA were performed with standard technique (four vessel catheterization) and multiple projections. Axial CT scans as well as maximum intensity projection, volume rendering and multiplanar reformations and angiographic views were independently reviewed by four readers (two for 64MDCT-angiography and two for DSA). Consensus was reached for discordant cases. DSA was considered as the standard of reference. RESULTS: In 29 patients, 28 aneurysms were found (14 patients had 1 aneurysm, 4 patients had 2 aneurysms and 2 patients had 3 aneurysms; in 9 patients no aneurysm were found). 64MDCT-angiography detected 26/28 aneurysms. No false-positive sites were recognized. The sensitivity, specificity, positive and negative predictive values and diagnostic accuracy were, respectively, 92.8, 100, 100, 99.4 and 99.5%. CONCLUSIONS: 64MDCT-angiography is helpful in detecting intracranial aneurysms with results similar to those of DSA but with less discomfort and risks for the patients and can be considered for the first line imaging technique. Conventional angiography is still needed in doubtful cases or negative MDCT-angiography associated with a strong clinical suspect.     

Comparison of intra-arterial digital subtraction angiography and conventional filming in peripheral vascular disease

We studied a series of 114 patients with ischemic peripheral vascular disease angiographically by conventional film-screen (CF) and by intra-arterial digital subtraction (DSA) techniques. The quality of films and images was evaluated at four anatomic levels. We reached the following conclusions: a) in most patients a DSA study will suffice for diagnosis; b) an ability to see arteries was related to the film or image quality; c) in the pelvis, although most studies were of excellent quality, more CF than DSA were of excellent quality; d) in the thigh, both CF and DSA studies were mostly of excellent quality; e) in the leg and foot, more DSA than CF studies were of excellent quality; f) patients preferred DSA to CF studies; g) physician acceptance of DSA was mixed; and h) good patient hydration can reduce the potential renal complications of the larger contrast loads used in CF studies.