Prospective Study of Polytetrafluoroethylene-Covered Microplugs and Detachable Coils for Embolization of Pulmonary Arteriovenous Malformations: Technical Results, Procedure Times, and Costs.

PURPOSE: To determine time to occlusion and procedure costs of embolization of pulmonary arteriovenous malformations (PAVMs) using a polytetrafluoroethylene-covered microplug compared with embolization using detachable coils. MATERIALS AND METHODS: In this prospective study, 37 patients (mean age, 39.1 years [SD ± 17.6]) with 82 PAVMs underwent embolization with microplug or detachable coils between April 2019 and January 2023. Technical success, procedure time intervals, and costs were analyzed. RESULTS: In 37 patients, 82 PAVMs and 101 feeding arteries were successfully treated (microplug, 64; microplug + another device, 5; detachable coils alone, 32). Time from embolic device inserted into the catheter to device deployed and time to occlusion differed significantly between microplug and detachable coil cohorts (P < .0001 for both). Embolization with ≥1 microplug had a significantly shorter occlusion time than embolization with detachable coils (median, 10.0 minutes saved per feeding artery) (P < .0001). Compared with detachable coil embolization, microplug embolization saved a median of 9.0 minutes per feeding artery (P < .0001) and reduced room cost by a median of $429 per feeding artery (P < .0001). Device costs per feeding artery did not differ significantly between microplug ($2,790) and detachable coil embolization ($3,147) (P = .87). CONCLUSIONS: Compared with coils, microplugs had an equally high technical success rate but significant time to occlusion and room costs savings per feeding artery. Total room cost and device cost together did not differ significantly between microplugs and coils. Microplugs may be considered technically effective and at least cost-neutral for PAVM embolization where clinically appropriate.

Hemodynamic Assessment of a Large Pulmonary Arteriovenous Malformation in a Neonate: Case Report and Review of Literature.

Herein we report the case of a neonate with a prenatally diagnosed large pulmonary arteriovenous malformation, managed with minimally invasive hemodynamic monitoring in our Neonatal Intensive Care Unit. The combination of Near-Infrared Spectroscopy and Pressure Recording Analytical Method could guide neonatal management of critical cases of vascular anomalies: immediate data are offered to clinicians, from which therapeutic decisions such as timing of surgical resection are made to achieve a positive outcome. We also systemically collected and summarized information on patients' characteristics of previous cases reported in literature to data, and we compared them to our case.

Assessment of pulmonary arteriovenous malformation with ultra-short echo time magnetic resonance imaging.

PURPOSE: The purpose of this study was to evaluate the diagnostic performance of ultra-short echo time magnetic resonance imaging (UTE MRI) in the assessment of pulmonary arteriovenous malformation (PAVM). METHODS: Eighteen consecutive patients (mean [± standard deviation] age, 48.6 ± 16.8 years) with 46 untreated PAVMs who underwent and thin-section computed tomography (CT) and UTE MRI with a 1.5-Tesla and 3-Tesla unit were retrospectively assessed. Two radiologists evaluated the diagnostic capabilities of UTE MRI for the detection and classification of PAVMs with reference to CT. Sensitivity, specificity, and kappa statistics were calculated with reference to CT. We also compared the differences in PAVM measurements between CT and MRI. RESULTS: The sensitivity and specificity of UTE-MRI for the detection of PAVMs were 89.1% and 100%, respectively, for reader 1 and 87.0% and 100%, respectively, for reader 2. In the classification of PAVMs, inter-modality agreement in reader 1 and 2 were both substantial (κ = 0.78 and 0.69, respectively). The measurements of the PAVM feeding artery and sac on CT and MRI were strongly correlated in both readers 1 and 2 (R2 = 0.981 and 0.983, respectively). Both readers 1 and 2 slightly underestimated the diameter of the PAVM feeding artery and sac on UTE MRI (p < 0.001). CONCLUSION: This study indicates that UTE MRI is a feasible and promising modality for noninvasive assessment of PAVMs.

Brain Iron Assessment after Ferumoxytol-enhanced MRI in Children and Young Adults with Arteriovenous Malformations: A Case-Control Study.

Background Iron oxide nanoparticles are an alternative contrast agent for MRI. Gadolinium deposition has raised safety concerns, but it is unknown whether ferumoxytol administration also deposits in the brain. Purpose To investigate whether there are signal intensity changes in the brain at multiecho gradient imaging following ferumoxytol exposure in children and young adults. Materials and Methods This retrospective case-control study included children and young adults, matched for age and sex, with brain arteriovenous malformations who received at least one dose of ferumoxytol from January 2014 to January 2018. In participants who underwent at least two brain MRI examinations (subgroup), the first and last available examinations were analyzed. Regions of interests were placed around deep gray structures on quantitative susceptibility mapping and R2* images. Mean susceptibility and R2* values of regions of interests were recorded. Measurements were assessed by linear regression analyses: a between-group comparison of ferumoxytol-exposed and unexposed participants and a within-group (subgroup) comparison before and after exposure. Results Seventeen participants (mean age ± standard deviation, 13 years ± 5; nine male) were in the ferumoxytol-exposed (case) group, 21 (mean age, 14 years ± 5; 11 male) were in the control group, and nine (mean age, 12 years ± 6; four male) were in the subgroup. The mean number of ferumoxytol administrations was 2 ± 1 (range, one to four). Mean susceptibility (in parts per million [ppm]) and R2* (in inverse seconds [sec-1]) values of the dentate (case participants: 0.06 ppm ± 0.04 and 23.87 sec-1 ± 4.13; control participants: 0.02 ppm ± 0.03 and 21.7 sec-1 ± 5.26), substantia nigrae (case participants: 0.08 ppm ± 0.06 and 27.46 sec-1 ± 5.58; control participants: 0.04 ppm ± 0.05 and 24.96 sec-1 ± 5.3), globus pallidi (case participants: 0.14 ppm ± 0.05 and 30.75 sec-1 ± 5.14; control participants: 0.08 ppm ± 0.07 and 28.82 sec-1 ± 6.62), putamina (case participants: 0.03 ppm ± 0.02 and 20.63 sec-1 ± 2.44; control participants: 0.02 ppm ± 0.02 and 19.65 sec-1 ± 3.6), caudate (case participants: -0.1 ppm ± 0.04 and 18.21 sec-1 ± 3.1; control participants: -0.06 ppm ± 0.05 and 18.83 sec-1 ± 3.32), and thalami (case participants: 0 ppm ± 0.03 and 16.49 sec-1 ± 3.6; control participants: 0.02 ppm ± 0.02 and 18.38 sec-1 ± 2.09) did not differ between groups (susceptibility, P = .21; R2*, P = .24). For the subgroup, the mean interval between the first and last ferumoxytol administration was 14 months ± 8 (range, 1-25 months). Mean susceptibility and R2* values of the dentate (first MRI: 0.06 ppm ± 0.05 and 25.78 sec-1 ± 5.9; last MRI: 0.06 ppm ± 0.02 and 25.55 sec-1 ± 4.71), substantia nigrae (first MRI: 0.06 ppm ± 0.06 and 28.26 sec-1 ± 9.56; last MRI: 0.07 ppm ± 0.06 and 25.65 sec-1 ± 6.37), globus pallidi (first MRI: 0.13 ppm ± 0.07 and 27.53 sec-1 ± 8.88; last MRI: 0.14 ppm ± 0.06 and 29.78 sec-1 ± 6.54), putamina (first MRI: 0.03 ppm ± 0.03 and 19.78 sec-1 ± 3.51; last MRI: 0.03 ppm ± 0.02 and 19.73 sec-1 ± 3.01), caudate (first MRI: -0.09 ppm ± 0.05 and 21.38 sec-1 ± 4.72; last MRI: -0.1 ppm ± 0.05 and 18.75 sec-1 ± 2.68), and thalami (first MRI: 0.01 ppm ± 0.02 and 17.65 sec-1 ± 5.16; last MRI: 0 ppm ± 0.02 and 15.32 sec-1 ± 2.49) did not differ between the first and last MRI examinations (susceptibility, P = .95; R2*, P = .54). Conclusion No overall significant differences were found in susceptibility and R2* values of deep gray structures to suggest retained iron in the brain between ferumoxytol-exposed and unexposed children and young adults with arteriovenous malformations and in those exposed to ferumoxytol over time. © RSNA, 2020.

Is there added value in obtaining cervical spine MRI in the assessment of nontraumatic angiographically negative subarachnoid hemorrhage? A retrospective study and meta-analysis of the literature.

OBJECTIVE Diagnostic algorithms for nontraumatic angiographically negative subarachnoid hemorrhage (AN-SAH) vary, and the optimal method remains subject to debate. This study assessed the added value of cervical spine MRI in identifying a cause for nontraumatic AN-SAH. METHODS Consecutive patients 18 years of age or older who presented with nontraumatic SAH between February 1, 2009, and October 31, 2014, with negative cerebrovascular catheter angiography and subsequent cervical MRI were studied. Patients with intraparenchymal, subdural, or epidural hemorrhage; recent trauma; or known vascular malformations were excluded. All cervical MR images were reviewed by two blinded neuroradiologists. The diagnostic yield of cervical MRI was calculated. A literature review was conducted to identify studies reporting the diagnostic yield of cervical MRI in patients with AN-SAH. The weighted pooled estimate of diagnostic yield of cervical MRI was calculated. RESULTS For all 240 patients (mean age 53 years, 48% male), catheter angiography was performed within 4 days after admission (median 12 hours, interquartile range [IQR] 10 hours). Cervical MRI was performed within 19 days of admission (median 24 hours, IQR 10 hours). In a single patient, cervical MRI identified a source for SAH (cervical vascular malformation). Meta-analysis of 7 studies comprising 538 patients with AN-SAH produced a pooled estimate of 1.3% (95% confidence interval 0.5%-2.5%) for diagnostic yield of cervical MRI. No statistically significant between-study heterogeneity or publication bias was identified. CONCLUSIONS Cervical MRI following AN-SAH, in the absence of findings to suggest spinal etiology, has a very low diagnostic yield and is not routinely necessary.

Jaw Immobilization for Gamma Knife Surgery in Patients with Mandibular Lesions: A Newly, Innovative Approach.

BACKGROUND: The purpose of our report is to describe an innovative system used for mandibular immobilization during Gamma Knife surgery (GKS) procedures. It is based on an approach originally developed in Marseille in extracranial lesions, close to or involving the mandible, which may imply a certain degree of movement during the therapeutic image acquisitions and/or GKS treatment. METHODS: The maxillofacial surgeon applied bone titanium self-tapping monocortical screws (4; 2 mm diameter, 10 mm length) between roots of the teeth in the fixed gingiva (upper and lower maxillae) the day before GKS (local anesthesia, 5-10 min time). Two rubber bands were sufficient for the desired tension required to undergo GKS. We further proceeded with application of the Leksell stereotactic G frame and carried out the usual GKS procedure. RESULTS: The mean follow-up period was 2.3 years (range 0.6-3). Three patients have been treated with this approach: 2 cases with extracranial trigeminal schwannomas involving the mandibular branch, with decrease in tumor size on MR follow-up; 1 case with residual paracondylian mandibular arteriovenous malformation following partial embolization, completely obliterated at 7 months (digital subtraction angiography programmed 1 year after treatment). CONCLUSIONS: Jaw immobilization appears to be a quick, minimally invasive, safe and accurate adjunctive technique to enhance GKS targeting precision.

Cost-Effectiveness Analysis of Percutaneous Sclerotherapy for Venous Malformations.

PURPOSE: To assess cost-effectiveness of sclerotherapy for venous malformations (VMs) to improve patient quality of life (QOL). MATERIALS AND METHODS: This prospective study enrolled 28 patients with symptomatic VMs who underwent sclerotherapy. EuroQol-5 Dimension (EQ-5D) and Short-Form 36 (SF-36) Health Survey were used to measure health-related QOL. Questionnaires were collected before and 1, 3, 6, and 12 months after sclerotherapy. Quality-adjusted life years (QALYs) were calculated using EQ-5D score as a measure of health utility. Medical costs obtained from the hospital accounting system and other costs of staff, drugs, materials, and angiographic equipment were calculated for each procedure. Cost-effectiveness was analyzed using incremental cost-effectiveness ratio (ICER) as the medical cost/gain of QALYs. RESULTS: Median EQ-5D scores improved from 0.768 (range, 0.705-1) to 1 (range, 0.768-1) after 6 months (P = .023) and 1 (range, 0.768-1) after 12 months (P = .063). The gain of QALYs at 12 months was 0.043. The mean medical cost was ¥281,228 ($2,337). The pain group (baseline bodily pain scale of SF-36 score < 70) showed greater improvement in median EQ-5D score, from 0.705 (range, 0.661-0.768) to 0.768 (range, 0.705-1) after 6 months (P = .041) and 0.768 (range, 0.768-1) after 12 months (P = .049). ICER at 12 months was ¥6,600,483 ($54,840) in the overall group and decreased to ¥3,998,113 ($33,218) in the pain group, < ¥6,000,000 ($49,850), threshold for acceptance of a public health benefit in Japan, even accounting for 50% increase in costs. CONCLUSIONS: Sclerotherapy was cost-effective for improving QOL for symptomatic VMs, especially for patients with moderate to severe pain.

Pancreatic involvement in hereditary hemorrhagic telangiectasia: assessment with multidetector helical CT.

PURPOSE: To evaluate and describe pancreatic involvement by using multidetector computed tomography (CT) in patients with a diagnosis of hereditary hemorrhagic telangiectasia (HHT). MATERIALS AND METHODS: Institutional review board approval was obtained, and all patients provided informed consent. Across 12 months, all consecutive adult patients with a confirmed diagnosis of HHT referred to our pluridisciplinary HHT center for evaluation were enrolled prospectively in the study and underwent contrast material-enhanced multidetector CT of the abdomen. Pancreatic telangiectases and arteriovenous fistulas were noted, and their characteristics were described. Genetic mutation was also investigated. RESULTS: Thirty-five patients (19 women, 16 men; mean age, 48.4 years) were included. All patients were asymptomatic. A genetic mutation was identified in 28 (80%) patients, including endoglin in 16 (57%), activin type-II-like receptor kinase 1 (ALK1) in 11 (39%), and SMAD4 in one (4%). Eleven (31%) patients exhibited pancreatic involvement. Fifty-four percent of patients with ALK1 mutation had pancreatic involvement. Twenty-three pancreatic telangiectases were identified during the arterial phase in nine patients. Seven pancreatic arteriovenous malformations (AVMs) were identified in four patients. CONCLUSION: Pancreatic involvement commonly is found in patients with HHT (31% in our study), mainly in patients with ALK1 mutation; pancreatic telangiectases or AVMs are only diagnosed duringthe arterial phase at multidetector CT.

Three-dimensional CT angiography for the diagnosis and assessment of arteriovenous malformations in the oral and maxillofacial region.

OBJECTIVE: The purpose of this study was to evaluate the diagnostic performance of three-dimensional computed tomography angiography (3D-CTA) for arteriovenous malformations (AVMs) in the oral and maxillofacial region. MATERIALS AND METHODS: Sixty four-slice spiral CT angiography of oral or maxillofacial region was performed in 8 patients with surgically proven arteriovenous malformations. The morphologic features, size, location, boundary, and feeding and draining vessels of lesions were reviewed. RESULTS: AVMs in 5 patients were located in the soft tissues and 3 were in the mandible. CTA of all cases showed tangles of disorganized vessels with well-defined borders. The feeding and draining vessels were enlarged and tortuous. Four patients had bone involvement. CONCLUSION: Sixty four-slice spiral CTA can accurately demonstrate the morphological characteristics of AVMs.

Arteriovenous malformation of the pancreas: assessment of clinical and multislice CT features.

BACKGROUND: This study was undertaken to analyze the clinical and CT features of arteriovenous malformation (AVM) of the pancreas. METHODS: Seven lesions in six consecutive patients (one woman and five men, mean age 51 years) with AVM of the pancreas who underwent multiphase contrast-enhanced CT with 0.5 or 1-mm collimation were retrospectively studied. CT images were evaluated and correlated with angiographic findings by two radiologists. RESULTS: In four patients, the lesions were incidental findings. Two patients presented with abdominal pain and gastrointestinal bleeding, respectively. Serum amylase levels were within normal limits in all patients. The mean size of the lesions was 32.1 mm (3.0-97.3 mm). Conglomeration of strong nodular stains and early enhancement of the portal venous system were observed for all the lesions. The diagnosis of AVM of the pancreas was retrospectively established for all lesions, but was prospectively established for four lesions. The feeding arteries of all lesions were depicted, showing agreement with those observed by angiography performed for four lesions. One lesion showed pseudocyst formation, haziness around the lesion, and strong enhancement of the duodenal wall. CONCLUSION: Multiphase CT examination using multislice CT is useful for diagnosis of AVM of the pancreas, including identification of the feeding arteries.

Advanced management of arteriovenous shunting malformation with transarterial lung perfusion scintigraphy for follow-up assessment.

AIM: The clinical assessment of arteriovenous malformations (AVMs), including treatment response (surgical and/or embolosclerotherapy), has traditionally been done by arteriography, mainly by looking for residual lesions. However, arteriography is disadvantaged as it is an expensive invasive test with high morbidity and provides only limited anatomical information at the qualitative level. Here, transarterial lung perfusion scintigraphy (TLPS), which was developed as a less invasive test for the physiologic assessment of the arteriovenous shunting status of AVM lesions located in the lower extremities, was evaluated for its ability to replace traditional arteriography as a means of following-up treatment results. METHODS: The shunting volume of radioisotope-tagged macro-aggregated albumin injected into the arterial system of the affected limb was counted by TLPS before and after AVM treatment, as a quantitative measure of treatment response. The findings obtained were compared with a matching duplex scan, whole body blood pool scintigraphy (WBBPS) findings, and arteriographic findings. RESULTS: Twenty-one TLPS tests were performed as follow-up assessments on 15 patients with AVM in the extremity, who underwent multistaged embolo/sclerotherapy alone or combined with surgical therapy. These 21 TLPS findings, including 6 interim TLPS results (average 16 months follow-up), provided quantitative measurements of lesion reductions as percentile ratios versus the baseline pretreatment values. Matching posttreatment duplex scan (14 out of 17 sets) and WBBPS (12 out of 15 sets) findings confirmed the posttreatment TLPS assessment. RESULTS: In addition, all 12 available arteriographic studies confirmed the matching TLPS findings. CONCLUSIONS: TLPS can provide accurate information on shunting volume reduction, occurring in response to various treatments during or after the completion of therapy. TLPS, therefore, may be able to replace arteriography, and provide a reliable means of follow-up assessment for the determination of the future treatment strategy.

Observer agreement in the angiographic assessment of arteriovenous malformations of the brain.

PURPOSE: We aimed to determine intraobserver and interobserver agreement in the characterization of brain arteriovenous malformation (AVM) angioarchitecture on intra-arterial digital subtraction angiograms. METHODS: Five experienced interventional neuroradiologists independently reviewed 40 anonymized angiograms obtained at the time of first-ever AVM diagnosis. The allocation of the films to observers was balanced for AVM size and complexity. Every observer was compared with himself and all the others by distributing the films in 2 batches 3 months apart. The observers used standard forms to collect both quantitative and categorized qualitative angiographic data. To measure agreement we used the kappa statistic (kappa) for nominal data, weighted kappa for ordinal and discrete interval data, and Bland & Altman analysis for continuous data. RESULTS: Intraobserver agreement was generally moderate to substantial, with 95% confidence intervals ranging from fair to almost perfect. However, for every characteristic, interobserver agreement was less than intraobserver agreement. Interobserver agreement was generally slight to moderate, with 95% confidence intervals ranging from less than chance to almost perfect. CONCLUSION: This study demonstrates the need for robust and generalizeable definitions of AVM angioarchitecture and methods of nidus size measurement-with proof of good intraobserver and interobserver agreement-for future efforts to understand the prognosis and best treatment of AVMs.

[Morphologic and functional assessment of vascular abnormalities of the pulmonary vasculature by breath-hold MR techniques]. / Morphologische und funktionelle Evaluation pulmonaler Gefässanomalien mittels schneller MR-Techniken.

PURPOSE: To evaluate breath-hold MR techniques for morphologic and functional assessment of vascular abnormalities of the pulmonary vasculature. PATIENTS AND METHODS: 13 patients aged 11 to 60 years with different vascular abnormalities of the pulmonary vasculature (5 patients with 16 arteriovenous malformations, 8 patients with partial anomalous pulmonary venous return) underwent MR imaging at 1.5 T. For morphological assessment, a contrast-enhanced 3D MR angiography (ce-MRA) was performed after a timing run. Segmented cine- and velocity-encoded GRE sequences were used for delineation of associated cardiac septal defects and for determination of systemic left-to-right or intrapulmonary shunt volumes. Selective intra arterial digital subtraction angiography, cardiac catheterization, and the intraoperative situs served as reference standards. RESULTS: Ce-MRA allowed for detection of all vascular abnormalities and for anatomic characterization of 14/16 arteriovenous malformations. Flow measurements in the feeding arteries allowed for determination of intrapulmonary shunt volumes in 4/5 patients. Flow measurements performed in the pulmonary arteries and the ascending aorta enabled determination of systemic left-to-right shunting in patients with anomalous pulmonary venous return. Cine-sequences clearly depicted associated cardiac septal defects. CONCLUSION: Breath-hold MR techniques allow for morphological and functional characterization of vascular anomalies of the pulmonary vasculature. Therefore, they are the non-invasive method of choice for planning further treatment.

Transvenous hemodynamic assessment of arteriovenous malformations and fistulas. Preliminary clinical experience in Doppler guidewire monitoring of embolotherapy.

BACKGROUND AND PURPOSE: Transvenous monitoring of blood flow through intracranial vascular malformations was performed with an intravascular Doppler guidewire to assess hemodynamic changes during endovascular embolotherapy. METHODS: Flow velocity was assessed in the intracranial venous sinuses of two patients with arteriovenous malformations and seven patients with dural arteriovenous fistulas. In all cases, the Doppler guidewire was positioned in the dural sinuses coaxially through a 2.1F microcatheter. The Doppler guidewire was then advanced to the site of arteriovenous shunting for sampling of venous average peak velocity (APV) and pulsatility index. In two cases, simultaneous feeding artery flow velocity was monitored by transcranial color-coded duplex sonography. RESULTS: Before embolotherapy, the flow pattern in the venous sinuses was pulsatile, with a mean (+/-SD) APV of 39.0 +/- 22.5 cm/s. Total or near-total embolization was achieved in six of the nine cases. After embolization, the flow pattern became less pulsatile and the APV was reduced to a mean of 21.2 +/- 14.6 cm/s (P = .0123, one-tailed paired t test). The pulsatility index was used to calculate the maximum minus the minimum peak velocity (MxPV-MnPV). This was reduced from an average of 27.0 +/- 8.7 cm/s to 13.5 +/- 8.3 cm/s after treatment (P = .0456). A parallel reduction in APV of the feeding arteries was observed with embolization. CONCLUSIONS: Preliminary clinical experience indicates that transvenous assessment of two parameters, APV and MxPV-MnPV, is useful in the hemodynamic evaluation of intracranial arteriovenous shunts. This valuable hemodynamic information may be used for objective and quantitative monitoring during embolotherapy of intracranial vascular malformations.

Transvenous hemodynamic assessment of experimental arteriovenous malformations. Doppler guidewire monitoring of embolotherapy in a swine model.

BACKGROUND AND PURPOSE: A Doppler guidewire was used to monitor progressive changes in draining vein flow parameters during experimental embolotherapy in a swine arteriovenous malformation (AVM) model. METHODS: A microcatheter was positioned superselectively in the main arterial feeder and main draining vein in each of 10 AVM models in swine. With use of the Doppler guidewire, preembolization arterial and venous average peak velocities (APVs) and pulsatility indices were recorded. The device was left in the draining vein during transarterial particulate (in 8 swine) or liquid adhesive (in 2 swine) embolization, and continuous transvenous flow during and after treatment was monitored. Periembolization Doppler flow parameters were correlated qualitatively with angiographic changes in the nidus. RESULTS: Preembolization draining vein flow was pulsatile, with a mean APV of 38.9 +/- 13.7 cm/s. After embolization, this changed significantly to a less pulsatile or nonpulsatile pattern, with a lower mean APV of 9.2 +/- 4.9 cm/s (P = .0001). A novel expression, the maximum minus the minimum peak velocity (MxPV-MnPV), was used in evaluating the transvenous Doppler spectra. This was reduced significantly after embolization from a mean of 11.1 +/- 3.5 cm/s to 6.7 +/- 2.5 cm/s (P = .0025). Objective periembolization hemodynamic changes were detected in the draining veins earlier than the visually subjective angiographic changes within the nidus. CONCLUSIONS: Transvenous Doppler guidewire assessment of two parameters, APV and MxPV-MnPV, is useful in the hemodynamic evaluation of experimental arteriovenous shunting and may be used for future objective and quantitative monitoring during endovascular AVM embolotherapy.

Hemodynamic assessment of vascular malformations by angio CT with generation of functional transit time images.

We performed a CT dynamic study during the first pass of an intravenously injected bolus of a iodinated contrast medium, followed by generation of the regional arm-brain circulation time (rABCT) image, in 11 patients with vascular malformations. All lesions could be detected as changes of rABCT, and the comparison with values of normal arteries and veins allowed the deduction of the hemodynamic conditions of the lesions. Seven cases showed evidence of altered distribution of rABCT in the corresponding brain hemisphere, suggesting a perfusion reserve impairment.

Assessment of major venous anomalies by computerized tomography.

Congenital anomalies of major venous structures are not common but their identification and relative position, particularly in relation to an abdominal aortic aneurysm, are of significant value in planning and conducting aortic operations. Computed tomography (CT) has become a common method of preoperative evaluation of aortic disease. Its reliability in providing accurate information regarding aneurysmal size, configuration, and extension, as well as the presence of intraluminal thrombus and involvement of the renal and iliac arteries, has been demonstrated. Simultaneous visualization of the major adjacent venous structures with the use of contrast enhancement is obtained, but anatomic variants can be overlooked because they are commonly subtle and considered incidental. The preoperative diagnosis of these venous abnormalities is significant to the vascular surgeon. Such information can be accurately and reliably acquired with the present CT techniques without the need for further diagnostic studies.

Complications of spinal cord arteriography: prospective assessment of risk for diagnostic procedures.

A prospective study was done of complications associated with 134 consecutive diagnostic spinal cord arteriograms in 96 patients (63 men and 33 women aged 17-78 years). Patients were examined for either arteriovenous malformation (n = 88) or tumor (n = 8), as indicated by myelography. Among the complications, 11 (8.2%) were local, five (3.7%) were systemic nonneurologic, and three (2.2%) were neurologic (two were associated with full recovery in less than 24 hours, and one was associated with full recovery in less than 1 week). No specific clinical or technical factors were significantly associated with the development of neurologic complications. Details of the clinical profile, angiographic technique, and pathologic findings for each patient were recorded and analyzed with respect to the potential risk for arteriographic complications. Diagnostic spinal cord arteriography had an acceptable risk within the range of other neuroangiographic diagnostic procedures.