Conventional Digital Subtraction Angiography Research Articles

Single‐dose time‐resolved contrast enhanced hybrid MR angiography in diagnosis of peripheral arterial disease: Compared with digital subtraction angiography

To prospectively study the diagnostic performance of hybrid single-dose contrast-enhanced MRA of peripheral arterial disease (PAD), with digital subtraction angiography (DSA) as the reference standard. Hybrid MRA, combining time resolved imaging of contrast kinetics and two-station bolus-chase sequences, of lower limb was performed in 31 PAD patients (21 men, 10 women; mean age, 72 years) with two separate gadobenate dimeglumine (8 mL) injections in each sequence. Two independent blinded readers analyzed the vascular stenosis (32 segments in each limb). Sensitivity, specificity, and accuracy in all vascular segments and segments below popliteal artery were calculated. Interobserver agreements on MRA and intermodality agreements between MRA and DSA were calculated by using k statistics. Sensitivity, specificity, and accuracy of the hybrid MRA with regard to hemodynamically significant stenosis in all vascular segments were 92%, 97%, and 95% for reader 1, and 90%, 92%, and 92%, for reader 2, respectively. The interobsever agreements on MRA were good (k = 0.77-0.74) for all-grade stenosis, and excellent (k = 0.82-0.81) for hemadynamically significant stenosis. The intermodality agreements are good to excellent (k = 0.73-0.94). Single-dose hybrid MRA is a safe and reliable noninvasive alternative to conventional DSA in the assessment of PAD patients.

64-Slice MDCT Angiography of Upper Extremity in Assessment of Native Hemodialysis Access

To compare multidetector row computed tomographic (MDCT) angiography with conventional digital subtraction angiography (DSA) in the evaluation of vascular access stenoses in hemodialysis patients. Twenty-one consecutive patients were imaged with MDCT angiography and subsequent DSA. The superficial vein of leg was used as the route for intravenous administration. The vascular stenosis was assessed in not significant (<50% stenosis), moderate stenosis (50%-74% stenosis), severe stenosis (75%-99%), and total occlusion (100%). The accuracy, sensitivity, specificity, positive, and negative predictive values were calculated for significant vascular stenosis using DSA as the standard reference. The sensitivity and specificity of MDCT angiography for the detection of significant hemodialysis vascular access were 100% (95% CI, 89.3%-100%) and 94.8% (95% CI, 89.1%-97.6%), respectively. The positive and negative predictive values were 84.2% (95% CI, 68.1%-93.4%) and 100% (95% CI, 95.8%-100%), respectively. The accuracy of MDCT angiography for detection of significant stenoses was 95.9% (95% CI, 91.4%-97.0%). MDCT angiography provides excellent correlation in vascular stenosis as compared with DSA in hemodialysis access. Complete assessment of entire vascular segments could be performing with MDCT angiography in planning before endovascular intervention or surgical correction.

Rezidivierende intrazerebrale Blutungen bei jüngeren Erwachsenen – Erst operative Exstirpation beweist Kavernome als Ursache

Wir diskutieren das therapeutische Vorgehen bei spontanen intrazerebralen Blutungen mit initial unklarer Ursache, bei denen kurzfristig signifikante Nachblutungen auftreten. Die Darstellung basiert auf 2 Fallberichten und einer kurzen Literaturübersicht. In beiden Fällen handelte es sich um junge Erwachsene mit initial leichtgradiger Klinik, bei denen eine singuläre supratentorielle intrazerebrale Blutung vorlag. Die Diagnostik einschließlich kranieller Magnetresonanztomografie (cMRT) und digitaler Subtraktionsangiografie (DSA) ergab jeweils keine Blutungsursache. Bei initial leichtgradiger Klinik wurde zunächst konservativ behandelt. Doch es kam innerhalb weniger Wochen zu Rezidivblutungen mit klinischer Verschlechterung, sodass in beiden Fällen nach erneuter Risikoabwägung operativ therapiert wurde. Intraoperativ und histopathologisch fand sich als Blutungsursache in beiden Fällen ein Kavernom. Anhand unserer beiden Fälle diskutieren wir das entsprechende diagnostische und therapeutische Problem.

Usefulness of C-Arm Cone-Beam Computed Tomography in Endovascular Treatment of Traumatic Carotid Cavernous Fistulas

Detailed information about the anatomy of traumatic carotid cavernous fistula (CCF) is required for determining the appropriate treatment strategy. We report the usefulness of C-arm cone-beam computed tomography (CBCT) for visualizing traumatic CCF during endovascular treatment. A 63-year-old woman presented with right pulsating tinnitus 1 week after a bicycle accident. Right internal carotid angiography demonstrated a right CCF but failed to visualize its precise location because the cavernous portion of the right internal carotid artery (ICA) was hidden by early filling of the cavernous sinus during both conventional digital subtraction angiography (DSA) and 3-dimensional digital angiography. C-arm CBCT, performed with a flat-panel detector mounted in a C-arm angiographic system, clearly depicted the tear in the medial wall of the C4 segment of the right ICA. Transarterial embolization with coils achieved complete occlusion of the CCF, and the patient's symptoms resolved immediately after the procedure. C-arm CBCT is useful to visualize the communication between the ICA and cavernous sinus and helps to determine the treatment strategy for traumatic CCFs.

2D Rotational Angiography for Fast and Standardized Evaluation of Peripheral and Visceral Artery Stenoses

To investigate the value of rotational digital subtraction angiography (rDSA) for evaluation of peripheral and visceral artery stenoses compared to conventional digital subtraction angiography (cDSA). A phantom study was performed comparing the radiation dose of cDSA with two projections and rDSA by means of the 2D Dynavision technique (Siemens Medical Solutions, Forchheim, Germany). Subsequently, 33 consecutive patients (18 women, 15 men; mean±SD age 67±15 years) were examined by both techniques. In total, 63 vessel segments were analyzed by two observers with respect to stenoses, image contrast, and vessel sharpness. Radiation dose was significantly lower with rDSA. cDSA and rDSA revealed 21 and 24 flow-relevant stenotic lesions and vessel occlusions (70-100%), respectively. The same stenosis grade was assessed in 45 segments. By means of rDSA, 10 lesions were judged to have a higher and 8 lesions a lower stenosis grade compared to cDSA. rDSA yielded additive information regarding the vessel anatomy and pathology in 29 segments. However, a tendency toward better image quality and sharper vessel visualization was seen with cDSA. rDSA allows for multiprojection assessment of peripheral and visceral arteries and provides additional clinically relevant information after a single bolus of contrast medium. At the same time, radiation dose can be significantly reduced compared to cDSA.

Imaging of angiogenesis: from morphology to molecules and from bench to bedside

Angiogenesis is one of the hallmarks of cancer and is increasingly in the focus of oncological research. Judah Folkman first articulated the importance of angiogenesis for tumor growth in 1971 [1]. He stated that the growth of solid tumors remains restricted to 2–3 mm in diameter until the onset of angiogenesis. Although this hypothesis first was strongly criticized, angiogenesis soon became one of the most important fields of research in oncology. Up to now, subsequent investigations have identified more than 20 angiogenic growth factors, their receptors and signal transduction pathways. Moreover, endogenous angiogenesis inhibitors have been discovered, and the cellular and molecular characterization of the angiogenic phenotype in human cancers has been achieved [2, 3]. Although the results of the first clinical trials using angiogenesis inhibitors in oncology were disappointing, encouraging results have been achieved in the past few years with the vascular endothelial growth factor (VEGF) antibody Avastin® in combination with standard cytotoxic chemotherapy. This combined antiangiogenic-cytotoxic therapy has been proven to be successful first in metastasized colorectal cancer, and subsequently also in breast cancer and non-small cell lung cancer [4–7]. This success of targeted antiangiogenic therapy will spur the demand for imaging modalities for assessment of the angiogenic cascade, which is the topic of this supplement “Imaging of Angiogenesis.” Imaging of angiogenic activity might on the one hand help in the process of developing novel antiangiogenic drugs in the preclinical setting. Moreover, in the clinical setting, imaging of angiogenesis might be useful for assessment of the optimum dose of new antiangiogenic agents and for early response evaluation. Up to now, clinical trials with conventional cytotoxic chemotherapeutic agents have mainly used morphological imaging to provide indices of therapeutic response, mostly computed tomography (CT) or magnetic resonance imaging (MRI). Bidimensional measurements of the maximum tumor extension are mainly used to estimate changes in response to the investigational therapy as compared with a baseline measure. Through standardization of these measurements by introducing the RECIST criteria in the year 2000, considerable progress has been achieved [8]. However, as antiangiogenic agents lead to a stop of tumor progression rather than to tumor shrinkage, the approach of measuring tumor response by a reduction of tumor size is not applicable and might take months or years to become apparent. Therefore, there is great interest in identifying reliable biomarkers of early tumor response to non-cytotoxic drugs [9]. Imaging techniques could potentially be used as such a biomarker and could provide an early indicator of effectiveness at a functional or molecular level. Concerning morphological imaging of the vasculature, conventional X-ray angiography and digital subtraction angiography (DSA) are widely used in the clinical arena; however, they do not allow for assessment of the microvasculature and thus are not commonly used for response evaluation of antiangiogenic therapies. More promising is the assessment of changes in hemodynamic parameters such as blood flow, blood volume, or vessel permeability. They may be effective biomarkers for response evaluation, because antiangiogenic therapies are designed to affect the abnormal blood vessels found in tumors. Current clinical trials employ various imaging techniques for this purpose, mostly dynamic contrast-enhanced MRI (DCE MRI), and less often ultrasound, PET (especially with [15O] water), and dynamic contrast-enhanced CT (DCE CT) [10]. In the future, targeting specific molecular markers of angiogenesis might also be used for response assessment of antiangiogenic therapies like the VEGF pathway or cell surface markers like the integrin αvβ3.

Intracranial arterial dissections in ischemic stroke assessed by 3D rotational angiography

BackgroundDissections involving intracranial arteries are sometimes difficult to assess using conventional digital subtraction angiography (DSA). We evaluated the value of three-dimensional rotational angiography (3D-RA) for the assessment of intracranial arterial dissections (ICADs). MethodsThe subjects were 39 patients (26 males, 13 females; average age 50±15years) who were diagnosed as having ICADs and who underwent both DSA and 3D-RA in our hospital between April 1999 and March 2005. We retrospectively compared 3D-RA images to conventional DSA images in a blinded manner with respect to double lumen sign, pearl and string sign, string sign, and aneurysmal dilatation. On the basis of the caliber size of the artery affected by dissections, we divided patients into two groups: smaller artery group (S group) and larger artery group (L group). ResultsThe detection rate of double lumen sign with 3D-RA (79%) was significantly higher than with conventional DSA (18%; P<0.001). Reliable findings of arterial dissections (double lumen sign and/or pearl and string sign) were observed more often with 3D-RA (90%) than with conventional DSA (36%; P<0.001). In S group, the double lumen sign was detected only with 3D-RA. Conclusions3D-RA allows increased conspicuity of ICADs findings with conventional DSA, especially in smaller-caliber intracranial arteries.

E-038 Utility of Dyna CT in the evaluation and management of cranial and skull base arteriovenous fistulas

IntroductionIntracranial dural arteriovenous fistulas (dAVFs) are comprised of pathologic, dural based shunts and account for 10–15% of all intracranial arteriovenous malformations. These lesions have complex anatomy that is best studied...

Three dimensional CT angiography versus digital subtraction angiography in the detection of intracranial aneurysms in subarachnoid hemorrhage

IntroductionRuptured intracranial aneurysms are responsible for over 90% of cases of spontaneous subarachnoid hemorrhage (SAH). Conventional digital subtraction angiography (DSA) remains the gold standard for diagnosing the source of SAH....

Evaluation of the vessels of the lower leg before microsurgical fibular transfer. Part II: magnetic resonance angiography for standard preoperative assessment

The peroneal artery is the dominant supply of the osteomyocutaneous fibular flap. It has been shown that there can be anatomical variants that could jeopardise the blood supply to the lower limb during harvest of the flap. To avoid postoperative ischaemia of the lower leg, preoperative evaluation of adequate collateral perfusion is essential. We investigated whether magnetic resonance angiography (MRA) accurately shows anatomical variants and pathological stenoses of the vessels of the lower leg and whether it can replace conventional invasive techniques. Conventional digital subtraction angiography (DSA) was used in a prospective study of 15 patients, and contrast-enhanced MRA postoperatively. Arteries were evaluated by three radiologists for: size of vessel at the trifurcation; hypoplastic or missing vessels; appreciable stenosis or vascular occlusion, or both; atherosclerotic malformations; and overall vascular topography. High resolution MRA enabled a reliable judgement to be made of the vessels of the lower leg. MRA definitively detected hypoplastic vessels, stenoses, occlusion, or atherosclerotic changes of the vessels, and enabled both accurate assessment of the quality of vessels and the preferred site for the harvest of the flap. As it is a low risk procedure, it can be done in the outpatient department with no risk of radiation. It can easily replace conventional DSA.

Application of multislice computed tomographic angiography in diagnosis and treatment of intracranial aneurysms

Objectives The aim of the study is to assess the clinical value of 16-row multislice computed tomographic angiography (CTA) for detection and treatment of intracranial aneurysms. Patients and methods Between January 2005 and October 2008, 388 patients were included and successively underwent 16-slice CTA for suspected intracranial aneurysms. Three neuroradiologists independently reviewed CTA and DSA images. The combined interpretations of digital subtraction angiography (DSA) and surgical findings were considered as the ultimate reference standard against which the diagnostic accuracy of CTA and DSA were compared. Results The reference standard revealed 287 aneurysms in 256 patients. There was no statistically significant difference in accuracy between 16-slice CTA and conventional DSA. The sensitivity, specificity, and accuracy of 16-slice CTA in detecting all aneurysms were 98.3, 97.0, and 97.9%, respectively, on a per-aneurysm basis. The sensitivity of 16-slice CTA was 90.0% for reader 1 and 93.3% for reader 2 for less than 3 mm aneurysms. One hundred eighty-nine aneurysms were deemed amenable to endovascular therapy on the basis of CTA images, 98% of whom (185) were successfully treated with this method. Forty-eight aneurysms were considered candidates for surgical treatment, and all aneurysms were deemed completely occluded during surgical clipping. Sixteen-slice CTA images provided important preoperative information, which could assist the endovascular and surgical therapy of aneurysms. Conclusions Sixteen-slice CTA is a highly accurate imaging examination of the first line imaging technique for the detection of intracranial aneurysms, and it can provide sufficient diagnostic information in guiding the surgical and endovascular therapy of aneurysms.

Feasibility of magnetic resonance angiography (MRA) follow-up as the primary imaging modality after coiling of intracranial aneurysms

Digital subtraction angiography (DSA) is still regarded as the gold standard for detecting residual flow in treated aneurysms. Recent reports have also shown excellent results from magnetic resonance angiography (MRA) imaging. This is an important observation, since DSA is associated with a risk of medical complications, is time consuming, and is more expensive. To determine whether MRA could replace conventional DSA and serve as the primary postinterventional imaging modality in patients with coiled intracranial aneurysms. We studied a prospectively enrolled cohort of 190 patients treated endovascularly for a first-ruptured and/or unruptured intracranial aneurysm between January 2004 and December 2008. The imaging protocol included a 1.5T time-of-flight (TOF) MRA and a DSA at 3 months (on the same day) and, depending on comparability, a 1.5T TOF-MRA or DSA 1 year after treatment. All images were evaluated by a multidisciplinary panel. In 141/190 patients, both an MRA and DSA were performed after 3-month follow-up. In 2/141 patients (1.4%), (small) neck remnants gave false-negative MRA results. In one patient (0.7%), this led to additional neurosurgical clipping of the aneurysm. In 25/141 patients, future follow-up (>3 months) consisted of DSA because of various reasons. In 24/25 of these patients, primary MRA images alone would invariably have led to additional DSA imaging. The present study shows that 1.5T TOF-MRA is a feasible primary follow-up modality after coiling of intracranial aneurysms. Given our data, we now suggest that, in every patient with a coiled intracranial aneurysm, the first follow-up, 3 months after coiling, should be an MRA study. Only when this MRA is inconclusive (e.g., because of coil artifacts), or in the case of suspicion of recanalization, should DSA be performed additionally.

Utility of C-arm CT in Patients with Hepatocellular Carcinoma undergoing Transhepatic Arterial Chemoembolization

To evaluate the utility of C-arm computed tomography (CT) on treatment algorithms in patients undergoing transhepatic arterial chemoembolization for hepatocellular carcinoma (HCC). From March 2008 to July 2008, 84 consecutive patients with HCC underwent 100 consecutive transhepatic arterial chemoembolizations with iodized oil. Unenhanced and iodinated contrast medium-enhanced C-arm CT with planar and three-dimensional imaging were performed in addition to conventional digital subtraction angiography (DSA) in all patients. The effect on diagnosis and treatment was determined by testing the hypotheses that C-arm CT, in comparison to DSA, provides (a) improved lesion detection, (b) expedient identification and mapping of arterial supply to a tumor, (c) improved characterization of a lesion to allow confident differentiation of HCC from pseudolesions such as arterioportal shunts, and (d) an improved evaluation of treatment completeness. The effect of C-arm CT was analyzed on the basis of information provided with C-arm CT that was not provided or readily apparent at DSA. C-arm CT was technically successful in 93 of the 100 procedures (93%). C-arm CT provided information not apparent or discernible at DSA in 30 of the 84 patients (36%) and resulted in a change in diagnosis, treatment planning, or treatment delivery in 24 (28%). The additional information included, amongst others, visualization of additional or angiographically occult tumors in 13 of the 84 patients (15%) and identification of incomplete treatment in six (7.1%). C-arm CT is a useful collaborative tool in patients undergoing transhepatic arterial chemoembolization and can affect patient care in more than one-fourth of patients.

3D rotational angiography with volume rendering: The utility in the detection of intracranial aneurysms

The advent of three-dimensional (3D) rotational angiography (3D DSA) challenged the role of digital subtraction angiography (DSA) as a "gold standard" in the diagnosis of intracranial aneurysms. In this study, we report our experiences in diagnosing intracranial aneurysms by using 3D DSA with volume rendering (VR) technique, particularly focusing on its role in depicting additional aneurysms missed by 2D DSA. One hundred and thirty-eight consecutive patients with known or suspected aneurysms (54 men, 84 women; median age, 55 years; age range, 18-83 years) underwent both conventional DSA and 3D DSA with VR examination simultaneously. The images of 2D DSA or 3D DSA with VR were evaluated by two observers independently for the presence of aneurysms. Then additional aneurysms were decided and depicted. 3D DSA with VR showed 146 aneurysms in 123 (89.1%) of 138 patients and no aneurysms in 15 patients. 2D DSA showed 115 aneurysms in 110 of 137 patients, with one aneurysm in 106 patients each, 2 in 3 patients each and 3 in 1 patient. After reaching a consensus, there were 31 additional aneurysms detected by 3D DSA with VR. 30 aneurysms were <3 mm in maximum diameter with 3 aneurysms ruptured. These additional aneurysms were located in internal carotid artery (ICA, n = 28, 90.32%), anterior cerebral artery (ACA, n = 3, 9.68%). No additional aneurysms were found in either middle cerebral artery (MCA) or vertebrobasilar and posterior cerebral artery (PCA) systems. 3D DSA, especially VR images, not only clearly reveals aneurysms and aneurysmal morphology, but also detects additional aneurysms missed by 2D DSA, especially small aneurysms less than 3 mm.

The valency of Magnetic resonance angiography (MRA) in patients with metal implants in the clinical routine

Introduction Magnetic resonance angiography (MRA) has shown a diagnostic accuracy, which is comparable to conventional digital subtraction angiography (DSA) regarding the highgrade stenosis. The advantage of MRA is the minimal invasiveness, resulting in an increasing employment in clinical routine. However, the image quality of MRA can be hampered by artifacts due to metal implants of joints and bones after surgery.

Benefits of Clipping Surgery Based on Three-Dimensional Computed Tomography Angiography

The recent development of three-dimensional computed tomography (3D-CT) angiography with multi detector row CT (MDCT) improves cerebral artery imaging due to faster scanning at thinner collimation over a large scanning volume. Aneurysm clipping was performed using only 3D-CT angiography created by MDCT with 16 detector arrays (16-MDCT angiography), in place of digital subtraction angiography (DSA) to evaluate the suitability of 16-MDCT angiography for preoperative examination before aneurysm clipping, and identify the essential points when making 3D images. Thirty-two patients with subarachnoid hemorrhage (SAH) identified by initial CT or with non-ruptured aneurysm were entered in this study. Twenty-six SAH patients underwent 3D-CT angiography, and aneurysms were treated by clipping (n = 25) or coil embolization (n = 4). One patient with no aneurysm depicted by 3D-CT angiography underwent conventional DSA twice subsequently. The sensitivity of 16-MDCT angiography to depict aneurysms in patients with SAH, and time between admission and entering the operating room were evaluated, and compared with those under the former protocol using DSA. The sensitivity of 16-MDCT angiography for aneurysm detection was 100%. Shapes of all aneurysms depicted by 3D-CT angiography were validated intra-operatively. The mean operation waiting time was 2.8 hours, with the shortest time being 1.5 hours. Re-bleeding occurred in one of the 20 patients. We conclude that shorter preoperative waiting time decreased the incidence of premature re-bleeding, resulting in better outcomes. We highly recommend that the surgeon sets the threshold value, and rotates the 3D image to establish better surgical orientation.

High-Resolution Steady State Magnetic Resonance Angiography of the Carotid Arteries: Are Intravascular Agents Necessary?

To prospectively evaluate the potential of gadobenate dimeglumine for high-resolution steady-state (SS) contrast-enhanced magnetic resonance angiography (CE-MRA) of the carotid arteries as an adjunct to conventional first-pass (FP) MRA, with computed tomography angiography (CTA) and digital subtraction angiography (DSA) as reference. Institutional ethics committee approval and written informed consent were obtained. Forty consecutive patients underwent conventional FP MRA with 15 mL gadobenate dimeglumine, using a conventional 3D FLASH sequence (14 sec acquisition time). Immediately afterward, SS images were obtained using a high resolution coronal 3D FLASH sequence (240 sec acquisition time). All patients also underwent CTA and conventional DSA within 8 +/- 3 days. Three experienced radiologists assessed FP and SS image quality and calculated sensitivity, specificity, accuracy, and predictive values for stenosis grade and length, plaque morphology, and tandem lesions using DSA as reference. Detected stenoses were quantified and compared (Spearman rank correlation coefficient, [R(s)]; McNemar test) with DSA and CTA findings. Inter-read variability was assessed using kappa (kappa) statistics. The impact of SS acquisitions on diagnostic confidence and patient management was assessed. MRA FP and SS image quality was excellent in 63 (78.8%) and 46 (57.5%) vessels, adequate in 11 (13.8%) and 20 (25.0%) vessels, and poor in 6 (7.5%) and 14 (17.5%) vessels, respectively. Area under the curve analysis revealed no significant differences between MRA FP, MRA FP + SS, and CTA for the grading of stenoses (P = 0.838; accuracy values of 97.4%, 97.4%, and 98.7%, respectively). Greater accuracy (P < 0.001) was noted for FP + SS images over FP images alone for the assessment of plaque morphology (96.1% for FP + SS images vs. 83.3% for FP). Increased diagnostic confidence was noted for 49 (61.3%) vessels because of additional SS images whereas an impact on final diagnosis was noted in 8 (10%) cases. Good correlation was noted between SS image quality and impact on final diagnosis (R(s) = 0.7; P < 0.0001). SS imaging of the carotid arteries is feasible with gadobenate dimeglumine. The increased spatial resolution attainable allows improved evaluation of stenoses and plaque irregularity, yielding comparable diagnostic performance to that of CTA and DSA.

Three-dimensional C-arm Cone-beam CT: Applications in the Interventional Suite

C-arm cone-beam computed tomography (CT) with a flat-panel detector represents the next generation of imaging technology available in the interventional radiology suite and is predicted to be the platform for many of the three-dimensional (3D) roadmapping and navigational tools that will emerge in parallel with its integration. The combination of current and unappreciated capabilities may be the foundation on which improvements in both safety and effectiveness of complex vascular and nonvascular interventional procedures become possible. These improvements include multiplanar soft tissue imaging, enhanced pretreatment target lesion roadmapping and guidance, and the ability for immediate multiplanar posttreatment assessment. These key features alone may translate to a reduction in the use of iodinated contrast media, a decrease in the radiation dose to the patient and operator, and an increase in the therapeutic index (increase in safety-vs-benefit ratio). In routine practice, imaging information obtained with C-arm cone-beam CT provides a subjective level of confidence factor to the operator that has not yet been thoroughly quantified.

Lessons from the Diagnosis and Treatment of Spontaneous Vertebral Arterial Dissection

A 36-year-old man presented a sudden left occipital headache and right limb weakness after tooth-brushing. Conventional catheter digital subtraction angiography (DSA) showed a left VA occlusion at the crotch of the posterior inferior cerebellar artery. Four days later, the patient got worse. The angiogram showed the left vertebral artery had reopened and the basilar trunk occluded above the AICA. He died two days later and autopsy demonstrated a dissection of the basilar arteries. Based on the autopsy data from the patient in this study, we suggest that the BA dissection might be due to left VA dissection, and placing a stent on the juncture between the uninjured VA and the basilar trunk might be an effective method to prevent fatal BA occlusion.

Subtraction CT angiography for evaluation of intracranial aneurysms: comparison with conventional CT angiography

The purpose of our study was to compare the diagnostic performance of subtraction computed tomography angiography (CTA) with conventional nonsubtracted CTA and digital subtraction angiography (DSA) for the detection of intracranial aneurysms. A total of 76 patients underwent both subtraction CTA and conventional CTA for the detection and therapy planning of suspected intracranial aneurysms. Subtraction and conventional CTA images were independently assessed by two readers in a blinded manner. The possibility of endovascular treatment or surgical clipping was also assessed based on information provided by CT angiograms alone. In 64 patients, 75 aneurysms were present on DSA. On a per-aneurysm basis, the sensitivity of subtraction CTA was 98.6% for reader 1, and 100% for reader 2. However, sensitivity of conventional CTA was 94.6% for reader 1, and 93.3% for reader 2. Therapeutic decisions could be made regarding 63 patients based on information provided by subtraction CTA images. However, conventional CTA provided sufficient information to make this decision for 55 patients. Conventional CTA has limited sensitivity in detecting very small aneurysms as well as aneurysms adjacent to bone. Subtraction CTA performed on a 64-row multidetector CT is an accurate and promising diagnostic tool that seems to be equivalent to 2D DSA for the detection and pretreatment planning of intracranial aneurysms.