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PubMed1996

Value of repeat-angiography in cases of unexplained subarachnoid hemorrhage (SAH).

PURPOSE: To investigate the rate of false negative initial cerebral angiography in spontaneous SAH and to ascertain why aneurysms remain undetected. Furthermore to validate CCT in predicting the presence and site of an angiographically missed aneurysm. METHODS: Forty-two patients with spontaneous SAH were investigated, in whom initial cerebral angiography did not reveal any bleeding cause. Repeat-angiography was performed in all patients 5 to 55 days (mean 15 days) after the bleeding event. All patients underwent CCT scans within 48h after the ictus. RESULTS: In 8 of 42 patients (19%) repeat-angiography revealed an aneurysm missed on initial angiography. The aneurysms were located on the AcomA (n = 2), the MCA (n = 2), the ACA (n = 1), the PICA (n = 2) and the junction of ICA and PcomA (n = 1). Presumable reasons for missing an aneurysm were spasms detected in four of eight cases on initial angiography and thrombosis of the aneurysm found in two cases at surgery. In two cases, multiple additional views just revealed the aneurysm appearing different in size and shape on repeat-angiography. CCT blood distribution pattern in four cases indicated presence and site of an aneurysm, while blood distribution was non-specific in the other four cases. CONCLUSION: Repeat-angiography plays an important role in defining the site of an initially occult aneurysm and should be performed in all cases of unexplained SAH. It is of particular importance if vasospasm has compromised the initial angiogram or if one part of the vascular tree is not optimally seen.

Adult↗
PubMed2003

Detection of submucosal gastric fundal varices with multi-detector row CT angiography.

BACKGROUND AND AIM: The diagnosis of submucosal fundal varices is challenging. Currently, endoscopy and endoscopic ultrasound (EUS) are considered most useful for this purpose. The aim of this study was to evaluate if multi-detector row CT (MDCT) angiography contributes to the diagnosis of submucosal fundal varices. PATIENTS AND METHODS: Twenty two patients with endoscopically suspected fundal varices were prospectively included in the study. All patients underwent EUS and MDCT angiography. Levels of agreement between EUS and MDCT angiography for the detection of submucosal and perigastric fundal varices were evaluated by three blinded independent readers. In addition, variceal size and location, as well as afferent and efferent vessels of the submucosal varices, were determined. RESULTS: Good or excellent image quality of MDCT angiography was obtained in 21/22 patients (95%). Based on EUS, submucosal varices were detected in 16 of 22 patients (73%) and perigastric varices in 22/22 patients (100%). Using MDCT angiography, the presence of submucosal varices was confirmed in all of these 16 patients by all three readers. Perigastric varices were also confirmed in all 22 patients by all three readers. In addition, all three readers noted the presence of a submucosal varix in an additional patient which was not detected on initial EUS. MDCT angiography showed an excellent interobserver reliability with regard to variceal diameter (kappa=0.90) and variceal location (kappa=0.94). Based on MDCT angiography, afferent and efferent vessels of submucosal varices included the left gastric vein in 11 (65%), the posterior/short gastric veins in 15 (88%), gastrorenal shunts in 10 (59%), the left inferior phrenic vein in six (35%), and the left pericardiophrenic vein in six (35%) of 17 patients. CONCLUSIONS: MDCT angiography is equivalent to EUS in terms of detection and characterisation of fundal varices, in particular with regard to the distinction between submucosal and perigastric fundal varices.

Adult↗
PubMed2005

Thromboembolic disease detection at indirect CT venography versus CT pulmonary angiography.

PURPOSE: To assess the incremental increase in thromboembolic disease detection at indirect computed tomographic (CT) venography versus CT pulmonary angiography and to determine the importance of scan interval for indirect CT venography on the basis of thrombus length. MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was not required. The study included 1590 consecutive patients undergoing CT pulmonary angiography for the suspicion of pulmonary embolism. Two minutes after completion of pulmonary angiography, a contiguous indirect CT venography was performed from the iliac crest to the popliteal fossa. The presence of pulmonary embolism or deep venous thrombosis (DVT) was recorded for all patients. The lengths of all deep venous thrombi found in the first 378 consecutive patients were recorded. RESULTS: Pulmonary embolism was detected in 243 (15%) of 1590 patients at CT pulmonary angiography, and DVT was detected in 148 (9%) patients at indirect CT venography. Among 148 patients with DVT, pulmonary embolism was detected in 100 patients at CT pulmonary angiography. Thus, the addition of indirect CT venography to CT pulmonary angiography resulted in a 20% incremental increase in thromboembolic disease detection compared with that at CT pulmonary angiography alone (99% confidence interval: 17%, 23%). Among the 378 patients, DVT was present in 33 patients at indirect CT venography. Two (6%) of 33 patients had clots measuring 2 cm or less, six (18%) had clots measuring 3-4 cm, and 25 (76%) had clots measuring more than 4 cm in length. CONCLUSION: The addition of indirect CT venography to CT pulmonary angiography incrementally increases the detection rate of thromboembolic disease by 20%. Performance of indirect CT venography by using contiguous section intervals, with a section width of 1 cm, is recommended to accurately detect DVT.

Adolescent↗
PubMed1992

Small hepatocellular carcinoma: diagnosis with US angiography with intraarterial CO2 microbubbles.

Ultrasonographic (US) angiography enhanced with intraarterial CO2 microbubbles, a contrast material used in US imaging, was performed of 103 histologically proved hepatocellular carcinomas (HCCs) smaller than 3 cm in diameter in 95 patients. The detection rate for hypervascular HCC with US angiography was compared with the rate of detection with conventional angiography, digital subtraction angiography (DSA), and computed tomography (CT) after intraarterial injection of iodized oil. Sensitivity in detection of hypervascular HCCs with US angiography was 86% (89 of 103 HCCs), compared with 63% (44 of 70 HCCs) detected with conventional angiography, 70% (23 of 33 HCCs) with DSA, and 82% (75 of 91 HCCs) with CT with iodized oil. US angiography depicted small hypervascular HCCs, especially those less than 1 cm in diameter, and helped clarify vascularity as isovascular or hypovascular in angiographically undetectable HCCs. Findings at US angiography assisted the choice of a therapeutic strategy for treatment of HCC, such as transarterial therapy, percutaneous ethanol injection therapy, or resection.

Angiography, Digital Subtraction↗
PubMed1998

Vascular complications of liver transplantation: evaluation with gadolinium-enhanced MR angiography.

PURPOSE: To evaluate use of gadolinium-enhanced magnetic resonance (MR) angiography in detection of vascular complications of liver transplantation. MATERIALS AND METHODS: Thirteen liver transplant recipients suspected to have vascular complications were evaluated with gadolinium-enhanced MR angiography by using a three-dimensional spoiled gradient-echo breath-hold technique during the arterial and venous phases of a high-dose (42 mL) bolus injection of gadolinium contrast material. Conventional angiography (n = 11) and surgery (n = 3) were used as the standard of reference. The transplant hepatic artery, celiac trunk, superior mesenteric artery, portal vein, superior mesenteric vein, splenic vein, hepatic veins, and inferior vena cava (IVC) were evaluated for thrombosis or stenosis by two radiologists. RESULTS: Ten vascular complications were identified with conventional angiography or surgery: transplant hepatic artery thrombosis (n = 3) or stenosis (n = 3), portal vein stenosis (n = 1) or occlusion (n = 2), and suprahepatic IVC stenosis (n = 1). All 10 complications were correctly diagnosed with MR angiography. There was agreement between results of MR angiography and conventional angiography or surgery in 58 of 62 vessels evaluated (94%). There was minor disagreement in four vessels (6%). CONCLUSION: Three-dimensional gadolinium-enhanced MR angiography may have the potential to enable accurate diagnosis of vascular complications of liver transplantation.

Adolescent↗
PubMed1998

Patency of coronary bypass grafts: assessment with breath-hold contrast-enhanced MR angiography--value of a non-electrocardiographically triggered technique.

PURPOSE: To determine the value of non-electrocardiographically triggered contrast material-enhanced magnetic resonance (MR) angiography in assessing the patency of venous and internal thoracic artery (ITA) grafts after coronary bypass surgery. MATERIALS AND METHODS: Twenty-seven patients with 76 coronary bypass grafts (48 venous, 28 ITA) were examined 26.5 months +/- 5.8 after surgery with MR angiography and conventional angiography. MR angiography was performed with a three-dimensional gradient-echo sequence after automated injection of contrast material; contrast agent administration was based on measurement of the individual transit time of the agent. Results of MR angiography were interpreted by two independent observers and compared with results of conventional angiography. RESULTS: The independent interpretations of the MR angiograms agreed with the results of conventional angiography in 96% and 91% of the grafts. After a final consensus reading, sensitivity was 95% for all grafts, 94% for venous grafts, and 96% for ITA grafts. Specificity was 85% for venous grafts and 67% for ITA grafts. Positive predictive value was 95% for all grafts, 94% for venous grafts, and 96% for ITA grafts. CONCLUSION: Non-electrocardiographically triggered contrast-enhanced MR angiography allows reliable assessment of the patency of venous and arterial coronary bypass grafts.

Adult↗
PubMed1999

Intracranial aneurysms: detection with three-dimensional CT angiography with volume rendering--comparison with conventional angiographic and surgical findings.

PURPOSE: To assess the diagnostic accuracy of three-dimensional (3D) computed tomographic (CT) angiography for intracranial aneurysms. MATERIALS AND METHODS: The 3D CT angiograms obtained in 49 patients with or without intracranial aneurysms were evaluated by four blinded observers. Results were compared with findings at conventional angiography or surgery. A volume-rendering method was used, and 13 images obtained in different directions were reviewed in each study. The diameter of aneurysms was divided into four sizes: large, greater than 13 mm; medium, 5-12 mm; small, 3-4 mm; and very small, less than 3 mm. Results were also evaluated by means of receiver operating characteristic analysis. RESULTS: At conventional angiography, 47 aneurysms, including 14 less than 3 mm, were depicted in 35 patients. The mean sensitivity of CT angiography for very small aneurysms was 64%; small, 83%; medium, 95%; and large, 100%. Some very small aneurysms that were not depicted at conventional angiography were depicted at CT angiography, and one was proved at surgery. CONCLUSION: CT angiography has good sensitivity for depiction of intracranial aneurysms 3 mm or larger and relatively good sensitivity for aneurysms less than 3 mm. CT angiography may be a noninvasive technique for detection of asymptomatic unruptured or ruptured aneurysms.

Adult↗
PubMed2003

Safety of limited supplemental iodinated contrast administration in azotemic patients undergoing CO2 angiography.

PURPOSE: To determine if limited doses of iodinated contrast significantly worsen the underlying renal insufficiency that had warranted the use of CO(2) for diagnostic angiography. METHODS: The records of 122 consecutive patients who had undergone CO(2) angiography for peripheral vascular disease at our institution over a 5-year period were reviewed. The volume and type of iodinated contrast and the volume of CO(2) administered were recorded. Serum creatinine measurements obtained before angiography and from 2 to 3 days after angiography were recorded. RESULTS: One hundred patients had pre-angiography and post-angiography creatinine levels available for analysis (51 CO(2) only, 49 CO(2) with iodinated contrast). The average pretreatment creatinine level was 2.8+/-1.5 mg/dL (range 1.8-6.6) for the CO(2) only group and 3.0+/-1.4 mg/dL (range 1.8-8.2) for the CO(2) plus iodinated contrast group (p=0.46). After angiography, the mean change in creatinine was +0.17+/-0.87 mg/dL for the CO(2) only group and +0.03+/-0.98 mg/dL in the CO(2) plus contrast group (p=0.27). Complications included 1 patient with a failing renal transplant who received iodinated contrast and ultimately required return to hemodialysis. A second patient had a transient 1-mg/dL rise of creatinine but did not require dialysis. CONCLUSIONS: This study supports the relative safety of CO(2) angiography with the limited used of iodinated contrast supplementation for diagnostic studies or interventions in azotemic patients with peripheral vascular disease.

Angiography↗
PubMed2002

Three-dimensional computed tomographic angiography with low loads of contrast agent in acute subarachnoid hemorrhage.

In the pre-operative evaluation of aneurysmal subarachnoid hemorrhage (SAH), three-dimensional computed tomographic angiography (3D-CTA) is very helpful. However, it is usually difficult to perform 3D-CTA following four-vessel cerebral angiography in the setting of acute SAH because of high loads of contrast agent. The present report is designed to enable 3D-CTA following catheter angiography for surgical planning. Fourteen consecutive patients with acute SAH underwent four-vessel cerebral angiography. After identification of the aneurysm, all patients were moved to the CT room next to the angiography room under catheterization. Contrast agent (10 ml) was diluted with 40 ml of heparinized saline. This diluted contrast agent was then injected through intra-arterial catheter for 3D-CTA. 3D-CTA with diluted contrast agent which was injected through intra-arterial catheter revealed sufficiently clear images. In addition, this method could provide anatomical information that was not readily available from catheter angiography. 3D-CTA with additional low dose of contrast agent can immediately follow four-vessel cerebral angiography in the setting of acute SAH. No complications were noted throughout the procedures. It has been our experience that the imaging modality in combination with not only catheter angiography but also 3D-CTA is advantageous in case of acute SAH and provides better detail for surgical planning.

Acute Disease↗
PubMed1995

Body magnetic resonance angiography and its effect on the use of alternative imaging--experience in 1026 patients.

Time-of-flight magnetic resonance (MR) angiography has been described for numerous applications but the number of patients described in published reports is usually relatively small. There is little information concerning the general utility of MR angiography in the body, outside the cranial circulation, or its effect on use of other imaging studies. Utilization of two-dimensional (2D) time-of-flight MR angiography over a 3 year period was reviewed to determine its accuracy and impact on other imaging modalities. Cranial and cardiac studies were excluded. Correlation was made with alternative imaging and surgical findings. Between January 1990 and December 1992 2D time-of-flight MR angiography was used to examine 1026 patients. MR angiography was used most frequently to examine the venous system. There was a slight reduction in the use of alternative imaging with two exceptions. When chest MR venography was performed, alternative imaging was completely abolished. Also, contrast portal venography was virtually eliminated. Five errors (0.2% of total MR angiography examinations) were recorded. Time-of-flight MR angiography, especially MR venography, is accurate and can replace contrast venography for abdominal and thoracic applications. Cost and limited availability means that other imaging, usually ultrasound, often precedes MR angiography.

False Negative Reactions↗
PubMed1998

CT angiography in vascular intervention for steno-occlusive diseases: role of multiplanar reconstruction and source images.

The aim of this study was to assess the efficacy of CT angiography for steno-occlusive diseases before and after interventional procedures, focusing on the role of multiplanar reconstruction (MPR) and source images. 17 patients with 20 steno-occlusive lesions underwent CT angiography before and after interventional procedures. For each lesion, the percentage stenosis obtained on CT angiography was compared with that on conventional angiography. In addition, MPR and source images were evaluated for the presence of wall thickening and calcification before interventional procedures, and the presence of dissection and luminal shape after interventional procedures. These findings were compared with those of conventional angiography. Although the percentage stenosis depicted on CT angiography correlated well with that on conventional angiography, MPR and source images clearly demonstrated the effect of intervention and the residual stenosis. MPR and source images clearly depicted wall thickening, wall calcification, the presence of dissection and the luminal shape. CT angiography provides useful information before intervention, while MPR and source images are of value in evaluating arterial wall abnormalities and morphological changes associated with interventional procedures.

Adult↗
PubMed1982

Digital subtraction angiography of the intracranial vascular system: comparative study in 55 patients.

Intracranial vessels were examined in 55 patients with both conventional selective catheterization and intravenous digital subtraction angiography using a prototype digital subtraction unit. In 65% of the patients, the digital subtraction angiogram was diagnostic, but the overall quality was inferior to conventional selective angiography. In 22%, the digital subtraction angiogram provided diagnostic information, but there was a significant chance of misinterpreting the results of the study. In 13% of cases, the subtraction angiogram was not diagnostic. As now developed, digital subtraction angiography can replace conventional cerebral angiography for preoperative evaluation of the juxtasellar carotid artery prior to transphenoidal surgery because the large intracerebral vessels are consistently well visualized with digital subtraction. The dural sinuses are better visualized with digital subtraction than with conventional angiography because with digital subtraction all the vessels of the brain are opacified, whereas with conventional angiography, there is a mixture of opacified and unopacified blood in the sinuses. Combined with computed tomography, digital subtraction angiography can replace conventional angiography for determining the preoperative extent and vascularity of tumors. It can be used for postoperative evaluation of aneurysms, arteriovenous malformations, extracranial to intracranial bypasses, and after the embolization of vascular lesions.

Adult↗
PubMed1994

Screening patients for renal artery stenosis: value of three-dimensional time-of-flight MR angiography.

OBJECTIVE: The purpose of this study was to determine the value of three-dimensional time-of-flight MR angiography in screening patients for the presence of renal artery stenoses. SUBJECTS AND METHODS: Fifty-three patients who were thought to have renovascular hypertension on clinical grounds were prospectively examined with three-dimensional time-of-flight MR angiography. IV digital subtraction angiograms and duplex sonograms were available for all patients. For 21 patients in whom IV angiograms were of high quality and showed the renal arteries to be normal, as confirmed with duplex sonograms, intraarterial digital subtraction angiograms were not obtained for MR correlation. In the other 32 patients, intraarterial angiograms of the abdominal aorta were obtained. MR angiograms were interpreted independently by two radiologists who were unaware of the findings on angiography and duplex sonography. Our preliminary clinical experience suggested that a signal loss in the renal arteries on maximum-intensity-projection MR angiograms indicated a potential stenosis and that the degree of stenosis could not be measured accurately with MR angiography. The search for stenoses was focused on the proximal and middle parts of the vessel, as far as 3 cm from the origin of the vessel. We used intraarterial angiography to measure and grade renal artery stenoses. On intraarterial angiograms, stenoses that involved more than 50% of the vessel's section were considered significant (n = 24) and stenoses that involved 50% or less of the section were considered insignificant (n = 7). These 31 stenoses were found in 26 of the 32 patients who had intraarterial digital subtraction angiography. RESULTS: All 24 significant stenoses appeared as a cutoff of signal intensity on MR angiograms. Results were false-positive in 20 cases: in eight cases, arteries were of small diameter; in seven cases, the stenoses were insignificant; in two cases, the acquisition volume was incorrectly positioned; in two cases, there was a sharp angle in the proximal part of the renal artery; and in one case, no explanation was found. MR angiography had a sensitivity of 100% for detecting stenoses in the proximal 3 cm of the renal artery; stenoses more than 3 cm from the origin of the arteries could not be detected reliably. CONCLUSION: Our results suggest that three-dimensional time-of-flight MR angiography is a simple method for detecting stenoses of the proximal portion of the main renal arteries. However, more work is needed before widespread clinical use of such a technique is feasible.

Angiography, Digital Subtraction↗
PubMed1995

Evaluation of the portal venous system before liver transplantation: value of phase-contrast MR angiography.

OBJECTIVE: The purpose of this study was to assess the accuracy of phase-contrast MR angiography with gadolinium in evaluating the patency and blood flow direction of the portal venous system; the presence, extent, and type of varices; and the patency of surgical decompressive shunts in patients before liver transplantation. This information is essential in management and care of patients with chronic liver disease and portal hypertension and those who are candidates for liver transplantation. SUBJECTS AND METHODS: Twenty-four patients with portal venous hypertension were evaluated with phase-contrast MR angiography. Two patients had surgical splenorenal shunts and one had a mesocaval shunt. Phase-contrast angiograms were acquired as a series of two-dimensional sequential coronal sections during breath-holding and after IV administration of gadopentetate dimeglumine. Correlative findings from color flow Doppler sonography, contrast-enhanced CT scanning, and conventional angiography were available in 23, 20, and 10 patients, respectively, and were used as standards. The images from each technique were analyzed independently for patency of and flow direction in the portal vein, splenic vein, superior mesenteric vein, and surgically created shunts, and for detection, distribution, and extent of five variceal groups. RESULTS: Findings from phase-contrast MR angiography completely agreed with those of sonography, CT scanning, and conventional angiography. The main portal vein was patent in 18 patients, stenosed in one, partially thrombosed in one, and occluded in four. Phase-contrast MR angiography correctly showed hepatofugal flow in three patients and hepatopetal flow in 17 patients. Both the splenic and superior mesenteric veins were patent in 20, partially thrombosed in one, and occluded in three cases. Phase-contrast MR angiograms showed 85% of the variceal groups, and MR rating of variceal size was not significantly different from that of CT rating. Phase-contrast MR angiography correctly showed the patency of all three surgical decompressive shunts. CONCLUSION: Phase-contrast MR angiography is accurate for evaluating the patency and flow direction of the portal venous system, detecting and determining the distribution and extent of varices, and assessing the patency of surgically created shunts. Therefore, it is a reliable and noninvasive technique that can provide crucial information in the preoperative workup of liver transplant recipients.

Adult↗
PubMed1995

Primary bone tumors: value of MR angiography for preoperative planning and monitoring response to chemotherapy.

OBJECTIVE: The purposes of our study were to investigate the use of MR angiography with two- (2D) and three-dimensional (3D) displays in evaluating vascular morphology of musculoskeletal neoplasms for preoperative planning of limb-salvage surgery and to assess the use of MR angiography for monitoring changes in neovascularity and evaluating response to chemotherapy. SUBJECTS AND METHODS: We used MR angiography (2D time-of-flight) to study 13 patients with primary bone tumors (nine osteogenic sarcomas, two Ewing's sarcomas, and two primary lymphomas of bone) at the time of initial presentation. Eight patients (all of whom had osteogenic sarcoma) also underwent MR angiography following chemotherapy before limb-salvage surgery. Two-dimensional maximum intensity projections were obtained. Three-dimensional reconstructions of vascular structures were created from the angiographic source images and were displayed simultaneously with 3D reconstructions of tumor and normal bone generated from conventional MR images. RESULTS: Two-dimensional maximum intensity projections were useful for evaluating small vessel neovascularity; 3D displays demonstrated spatial relationships of tumor, feeder vessels, and normal vascular structures. Tumor encroachment onto or encasement of normal vascular structures was shown in four patients on 2D maximum intensity projections and on 3D displays. The eight patients with osteogenic sarcoma who had follow-up imaging showed marked neovascularity prior to chemotherapy. Five patients responded to chemotherapy (> or = 90% tumor necrosis at histology); MR angiography showed marked reduction in tumor neovascularity in these patients. Three patients did not respond to chemotherapy; MR angiography showed unchanged neovascularity in one and increased neovascularity in two of these patients. CONCLUSION: MR angiography provides good visualization of peripheral vascular branches and tumor neovascularity in patients with primary bone tumors. MR angiography demonstrates encroachment onto and encasement of major vessels by the tumor mass and appears to be useful for assessing response to chemotherapy in osteogenic sarcoma and possibly other primary bone tumors by detecting treatment-induced changes in tumor neovascularity.

Adolescent↗
PubMed1996

MR angiography for mapping potential central venous access sites in patients with advanced venous occlusive disease.

OBJECTIVE: Patients who depend on long-term central venous catheter support frequently develop thrombi in central veins. An accurate, noninvasive technique is needed to find patent central veins for future access. We evaluated the suitability of MR angiography for this use. SUBJECTS AND METHODS: Using five healthy volunteers and 19 patients who had malfunctioning central venous catheters and a history of central venous occlusive disease, we tested the ability of MR angiography to assess central vein status. Three radiologists experienced in MR angiography blindly interpreted both source images and three-dimensional reconstructed images. RESULTS: In the volunteers, MR angiography provided diagnostic-quality images of the internal and external jugular, innominate, subclavian, axillary, femoral, and iliac veins, and of the superior and inferior venae cavae. Interobserver interpretations did not vary. In the patients, MR angiography of venous patency was confirmed by venography in 27 segments, by sonography n 32 segments, and by attempted line placement in 21 placements. Images were diagnostically adequate in 206 of 216 segments (95%). For detection of occlusion, sensitivity was 97% and specificity was 94%. MR angiography predicted 100% of successful line placements and 80% of failures. Interobserver interpretations varied by 44%. MR angiography directly influenced therapy in 19 of 21 studies. CONCLUSION: We conclude that MR angiography provides risk-free, thorough, relatively accurate, and clinically useful assessment of most available central venous access sites, although interpretation may prove difficult in patients with extensive occlusions because of complex collateral drainage patterns.

Adolescent↗
PubMed1999

MR angiography as a screening tool for intracranial aneurysms: feasibility, test characteristics, and interobserver agreement.

OBJECTIVE: MR angiography may be an appropriate tool to screen for unruptured intracranial aneurysms. Feasibility, test characteristics, and interobserver agreement in evaluation of MR angiograms were assessed by members of the MARS (Magnetic resonance Angiography in Relatives of patients with Subarachnoid hemorrhage) Study Group. SUBJECTS AND METHODS: We screened 626 first-degree relatives of a consecutive series of 193 patients with subarachnoid hemorrhage examined at two institutions. We used MR imaging and MR angiography (three-dimensional time-of-flight imaging at both institutions and additional three-dimensional phase-contrast imaging at one institution). Three observers independently assessed the MR angiograms. Conventional angiography was performed in relatives with possible or definite aneurysms on MR angiography and was considered the standard of reference. RESULTS: Thirty-three aneurysms were found in 25 (4%; 95% confidence interval [CI], 3-6%) of 626 relatives. Thirteen (8%) of 169 relatives who refused screening had MR-related reasons; an additional six persons could not be screened because of contraindications for MR imaging (pregnancy, n = 1; claustrophobia, n = 5). The positive predictive value of MR angiography was 100% (95% CI, 79-100%) for "definite" aneurysms and 58% (95% CI, 28-85%) for "possible" aneurysms. Sensitivity of MR angiography was estimated at 83% (95% CI, 65-94%) and specificity at 97% (95% CI, 94-98%). Interobserver agreement in the evaluation of MR angiograms was poor (kappa < .30), probably because different diagnostic strategies used by individual observers resulted in different use of the assessment category "possible aneurysm." CONCLUSION: MR angiography is a feasible screening tool for detection of intracranial aneurysms. Positive predictive value, sensitivity, and specificity are acceptable when at least two neuroradiologists independently assess MR angiograms.

Adult↗
PubMed2000

Pulmonary embolism revealed on helical CT angiography: comparison with ventilation-perfusion radionuclide lung scanning.

OBJECTIVE: We compared helical CT angiography and ventilation-perfusion radionuclide lung scanning as initial tests in the diagnosis of acute pulmonary embolism. SUBJECTS AND METHODS: Two hundred sixteen consecutive patients who were clinically suspected of having acute pulmonary embolism underwent helical CT angiography, ventilation-perfusion radionuclide lung scanning, and Doppler sonography of the veins of the legs. On the basis of concordance of the results for ventilation-perfusion radionuclide lung scanning and helical CT angiography and on the degree of clinical suspicion, certain patients underwent pulmonary angiography. Patients without pulmonary embolism at initial evaluation in whom no treatment was instituted were followed up for at least 3 months to determine the potential recurrence of thromboembolic disease. RESULTS: Of the 216 patients, 37 (17%) were excluded because of insufficient data to assess the initial event. Final diagnosis for the 179 remaining patients was pulmonary embolism in 68 (37.9%) and no pulmonary embolism in 111 (62.0%), based on pulmonary angiography in 23 patients (12.8%) and concordant imaging findings and outcome in the remaining patients. Statistically significant differences (p < 0.05) were found between sensitivity, specificity, positive predictive value, and negative predictive value for helical CT angiography and ventilation-perfusion radionuclide lung scanning (94.1% versus 80.8%; 93.6% versus 73.8%; 95.5% versus 82%; and 96.2% versus 75.9%, respectively). Interobserver agreement was excellent for helical CT angiography (kappa = 0.72) and moderate for ventilation-perfusion radionuclide lung scanning (kappa = 0.22). CONCLUSION: Helical CT angiography could replace ventilation-perfusion radionuclide lung scanning as the initial test for screening patients who are clinically suspected of having pulmonary embolism.

Acute Disease↗