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At least 19 recordsLinked to original sources
PubMed2006

Computed tomography angiography and computed tomography perfusion in ischemic stroke: A step-by-step approach to image acquisition and three-dimensional postprocessing.

Recent technical advances in both image acquisition and postprocessing have enabled computed tomography angiography (CTA) with computed tomography perfusion to become front-line tools for acute stroke evaluation in many institutions. This article provides a step-by-step approach to utilizing these technologies, particularly in the rapid triage of appropriate stroke patients to reperfusion therapies. The specific contrast injection, image acquisition, and 3D postprocessing protocols for high-quality CTA, currently in use at our institution, are delineated. An important point of emphasis is how preliminary angiographic and cerebral perfusion observations can be made immediately at the scanner to expedite emergent therapy. Also explored is the manner in which a dedicated 3D lab can support a high clinical volume, including a large percentage of emergent studies. An accurate yet time-efficient approach for the neuroradiologist to integrate 3D interpretation with CTA source data review is offered. Several important imaging and interpretive pitfalls in stroke CTA are illustrated.

Angiography↗
PubMed2005

Patient with Leriche's syndrome and concomitant superior mesenteric aneurysm: evaluation with contrast-enhanced three-dimensional magnetic resonance angiography, computed tomography angiography and digital subtraction angiography.

Conventional angiography is regarded as the gold standard in vascular imaging but it is invasive, and difficulty may be encountered in the evaluation of aortic occlusion disease. Superior mesenteric artery aneurysm is an uncommon disease, which can result in life-threatening haemorrhage after rupture. With the rapid development of computed tomography angiography (CTA) and magnetic resonance angiography (MRA), high-quality images of the vascular system can be obtained in a non-invasive manner. We report a case of Leriche's syndrome with concomitant superior mesenteric aneurysm using contrast-enhanced 3-D CTA and MRA, with digital subtraction angiography correlation.

Aneurysm↗
PubMed1996

Variability of magnetic resonance angiography and computed tomography angiography in grading middle cerebral artery stenosis.

BACKGROUND AND PURPOSE: Magnetic resonance angiography and computed tomography angiography are new, noninvasive methods to provide images of the cerebral vasculature. The reliability of magnetic resonance angiography and computed tomography angiography when used to grade middle cerebral artery stenosis remains to be established. We sought to study the interobserver and intraobserver variabilities of magnetic resonance angiography and computed tomography angiography in grading middle cerebral artery stenosis. METHODS: A total of 50 middle cerebral arteries in 25 patients were studied with magnetic resonance angiography and computed tomography angiography. All patients had a history of ischemic stroke. The films were read independently by two observers on separate occasions. Films were shown again to the same observer 4 weeks after the first reading. The degree of middle cerebral artery stenosis was categorized into four grades: normal/mild, moderate, severe, and occluded. The interobserver and intraobserver variabilities were calculated by the kappa statistic method. RESULTS: Interobserver variability for grading middle cerebral artery stenosis was good (kappa = 0.78) for magnetic resonance angiography and moderate (kappa = 0.51) for computed tomography angiography. There was perfect agreement between two observers in 86% of the vessels shown in magnetic resonance angiography and in 76% of the vessels shown in computed tomography angiography. Intraobserver variability for both imaging methods was good, with the kappa value in the range of 0.70 to 0.76. CONCLUSIONS: Our results suggest that according to our protocol, magnetic resonance angiography is more reliable than computed tomography angiography in grading middle cerebral artery stenosis.

Adult↗
PubMed1996

Computed tomography angiography.

Spiral computed tomography angiography is a relatively new noninvasive technique capable of rapid imaging of the carotid artery. Computed tomography angiography usually is performed in a 30-second scan time and images iodinated contrast as it fills the vascular lumen. Studies comparing computed tomography angiography with conventional angiography show sensitivities and specificities that rival any of the other noninvasive imaging techniques for the detection of carotid artery stenosis and occlusion.

Angiography↗
PubMed1995

Transcranial color-coded duplex sonography, magnetic resonance angiography, and computed tomography angiography: methods, applications, advantages, and limitations.

Transcranial color-coded duplex sonography (TCCD), magnetic resonance angiography (MRA), and computed tomography angiography (CTA) are novel noninvasive or minimally invasive techniques for the study of the intracranial circulation. TCCD is relatively inexpensive and permits bedside examination. It improves the accuracy and reliability of conventional transcranial Doppler studies. The main limitation of TCCD are the ultrasonic windows. They restrict the area of insonation to the major cerebral arteries and the proximal part of its branches, lower the spatial resolution, and may prevent transtemporal insonation. Using MRA, both large and small intracranial arteries and veins can be imaged by selecting the appropriate imaging parameters. MRA provides morphologic information about the cerebral vessels, relying on blood flow as the physical basis for generating contrast between stationary tissues and moving spins. MRA is highly sensitive for the detection of occlusive disease in large intracranial arteries. However, with bright blood techniques the degree of stenosis tends to be exaggerated. Flow direction, eg, in collaterals, can be determined by selective or phase-contrast MRA. Perfusion imaging techniques provide information about blood flow at the capillary level. Diffusion imaging depicts molecular motion. TCCD and MRA used in combination or alone may eliminate the need for intra-arterial digital subtraction angiography (DSA) in most patients studied for occlusive cerebrovascular disease. DSA may be reserved for those patients where there is disagreement among the noninvasive techniques, and for the diagnosis of cerebral aneurysms and arteriovenous malformations. CTA relies on spiral CT technology and intravenous contrast injection. To date, intracranial use has been predominantly for the diagnosis of aneurysms. The role of CTA for the detection of nonaneurysmal intracranial vascular disease has yet to be established.

Adult↗
PubMedDate not supplied

Evaluation of the hepatic artery in potential donors for living donor liver transplantation by computed tomography angiography using multidetector-row computed tomography: comparison of volume rendering and maximum intensity projection techniques.

PURPOSE: To compare the volume rendering (VR) and maximum intensity projection (MIP) computed tomography angiography (CTA) techniques using multidetector-row CT for hepatic artery evaluation of potential donors for living donor liver transplantation (LDLT). METHOD: Over a 9-month period, CTA using multidetector-row CT and conventional angiography was performed in 62 consecutive potential donors for LDLT. Acquisition of arterial phase scans was initiated within 5 seconds after reaching enhancement of the descending aorta up to 70 HU as measured by a bolus-tracking technique (collimation = 1.25 mm, table speed = 7.5 mm, reconstruction interval = 0.625 mm). Postprocessing was performed on a commercially available workstation. Computed tomography angiography images of the hepatic artery were made using the VR and MIP techniques. A total of 10 to 30 images of various planes were generated to reveal the origins and branching patterns of hepatic arteries. With a 2-week interval, two reviewers separately evaluated CTA using VR and MIP techniques, specifically evaluating anatomic variations and hepatic arterial conspicuity. The results of conventional angiography were considered to represent the gold standard. The difference in postprocessing time between the two techniques was statistically analyzed by the Student t test, and the differences in arterial conspicuity and in the identified number of the hepatic artery to segment IV of the liver were analyzed by the chi2 test. RESULTS: Two CT examinations (3%) were technically inadequate for generating CTA because of respiratory motion artifact. The average times for postprocessing of VR and MIP images were 8.1 +/- 3.8 minutes and 5.0 +/- 0.7 minutes, respectively. Variations of hepatic arterial anatomy were present in 19 patients (32%) on conventional angiography. In 8 patients (13%), there was discrepancy in the variations of hepatic arterial anatomy between the two techniques: MIP was correct in 7 patients, and VR was correct in 1 patient. The dominant artery supplying segment IV was identified in 51 patients (85%) with MIP and in 39 patients (65%) with VR. There was no significant difference in conspicuity of the hepatic arteries using either the MIP or VR technique. CONCLUSION: In CTA techniques using multidetector-row CT, MIP is superior to VR for the hepatic arterial evaluation of potential LDLT donors in terms of depicting anatomic variations and postprocessing time.

Adolescent↗
PubMed2004

Multislice computed tomography angiography of the abdominal arteries: comparison between computed tomography angiography and digital subtraction angiography findings in 52 cases.

Since the introduction of multislice CT scanners, CT angiography (CTA) has become a powerful tool for imaging the vascular system. We compare conventional angiography to CTA in the diagnosis of morphological changes in the abdominal aorta and its branches. A retrospective analysis of 52 patients who underwent both multislice CT angiography (MSCTA) and digital subtraction angiography before surgical treatment is presented. All CT examinations were performed after administration of 100 mL contrast medium with a collimation of 4 x 1 mm and a pitch of 7. A standardized evaluation of the axial, multiplanar and 3D reconstructions was performed by two experienced radiologists. Stenoses were classified as high-grade and low-grade, and aneurysms, occlusions and arteriosclerosis were evaluated. The CTA findings were compared with conventional angiography. All aneurysms, occlusions, stenoses and calcifications were diagnosed correctly by CTA in axial and multiplanar projections (sensitivity 1.0; specificity 1.0). The degree of stenosis was overestimated in three cases when using axial projections. Three-dimensional volume-rendered CTA showed a sensitivity of 0.91 for aneurysms, 0.82 for stenoses, 0.75 for occlusions and 0.77 for calcifications. The specificity was 1.0 in all cases. Multislice CT angiography seems to be similar to conventional digital subtraction angiography for abdominal vessels if multiplanar projections are used.

Aged↗
PubMed2000

Subepicranial varix mimicking sinus pericranii: usefulness of three-dimensional computed tomography angiography and bone window computed tomography--case report.

A 16-year-old female presented with a rare case of subepicranial varix in the left temporal area manifesting as a soft mass in the left temporal area when she laid down in the left lateral position. Bulging of the mass was observed when intracranial venous pressure was raised by the Valsalva maneuver, the left lateral position, or the prone position. Bone window computed tomography (CT) revealed a tiny hole, 1 mm in diameter, in the outer bone table. Three-dimensional CT (3D-CT) angiography clearly visualized a mass with a diameter of approximately 10 mm connected to the diploic vein. The mass was totally resected by operation. Venous bleeding was observed from the tiny hole. Histological examination revealed a venous lesion mimicking sinus pericranii and containing endothelial cells. No communication with the intracranial venous sinuses was identified, so the diagnosis was subepicranial varix. Radiological examination by direct injection of contrast medium is usually performed to identify subepicranial varix, but 3D-CT angiography is a non-invasive preoperative examination that can visualize this small venous lesion. Adjustment of the CT acquisition conditions may allow 3D-CT angiography to identify sinus pericranii in the future.

Adolescent↗
PubMed2006

Atherosclerotic plaque characterization by multidetector row computed tomography angiography.

Multidetector row computed tomography angiography (MDCTA) is seen as a potential alternative to current imaging methods for the assessment of vessel anatomy and atherosclerotic plaque composition/morphology in a great variety of arterial beds. Recent advances represented by the increase in gantry speed to <500 ms per rotation and in the number of detector rows from 4 to 64, in addition to the decrease in slice thickness to submillimetric levels, brought significant improvement in diagnostic accuracy by coronary MDCTA. In general, it has a good correlation with both intravascular ultrasound (IVUS) and histopathology for discrimination between soft, intermediate, and calcified plaques. Plaque area and volume tend to be underestimated by 12-detector row MDCTA and overestimated by 16-detector row MDCTA, but the number of patients studied so far is relatively small. However, it seems that 64-detector row MDCTA can measure plaque area and volume with greater accuracy. Plaque remodeling is overestimated in small vessels by 12-detector row MDCTA, whereas 16- and 64-detector row MDCTA show a good correlation with IVUS. Although still under development, the potential of MDCTA to characterize atherosclerotic plaque composition as well as to precisely determine plaque area, volume, and remodeling in the future is quite promising.

Angiography↗
PubMed2004

Gadolinium-enhanced computed tomography angiography in multi-detector row computed tomography: initial observations.

RATIONALE AND OBJECTIVES: The feasibility of using gadolinium contrast medium for computed tomography angiography (CTA) in multi-detector row computed tomography and the effect of contrast medium dilution was investigated. MATERIALS AND METHODS: Three pigs were each scanned in multiple sessions with injections of non-dilute and dilute contrast medium at a dose of 0.3 mmol/kg body weight. Non-spiral dynamic scanning at a fixed mid-abdominal aortic level and thoracoabdominal CTA were performed. RESULTS: The magnitude of peak aortic enhancement was not significantly different between dilute and non-dilute contrast medium injections (P = .88), but the former showed earlier enhancement (mean of 2.3 seconds sooner, P < .01) than the latter. CT angiography with gadolinium contrast medium showed much lower enhancement than iodine contrast medium, but small vessels were readily identifiable. CONCLUSION: Gadolinium contrast medium combined with multi-detector row computed tomography may provide clinically useful CTA. Dilution of contrast medium shortens the enhancement time but has little effect on the magnitude.

Angiography↗
PubMed2006

An unusual renal vascular anomaly: common origin of arteries to the lower poles demonstrated by a computed tomography angiography using 16-slice multidetector computed tomography.

Arterial connection between the left and right kidneys is extremely rare. Only eight cases of such anomalous conditions have been reported in the world literature and all were confirmed by invasive angiography or dissection. We report a patient with this vascular anomaly clearly demonstrated by 16-slice multidetector computed tomography.

Angiography↗
PubMedDate not supplied

Cervical radiculopathy caused by vertebral artery loop formation: multislice computed tomography angiography findings.

Vertebral artery tortuosity and loop formation are rare causes of cervical radiculopathy. The criterion standard for the detection of vertebral artery loop formation is digital subtraction angiography. Computed tomography (CT) and magnetic resonance imaging provide good accuracy in the evaluation of vertebral arteries. A case of vertebral artery loop formation is reported. The diagnosis was confirmed by 16-row multisection CT angiography findings of vertebral artery loop formation.

Adult↗
PubMed2006

3 T contrast-enhanced magnetic resonance angiography for evaluation of the intracranial arteries: comparison with time-of-flight magnetic resonance angiography and multislice computed tomography angiography.

PURPOSE: We sought to prospectively evaluate the image quality and visualization of the intracranial arteries using high spatial resolution contrast-enhanced magnetic resonance angiography (CE-MRA) at 3 T and to perform intraindividual comparison with time-of-flight (TOF) MRA and multislice CT angiography (CTA). MATERIALS AND METHODS: Twelve patients (5 men, 7 women, 37-71 years of age) with suspected cerebrovascular disease prospectively underwent MRA and CTA. MRA was performed on a 3 T MR system, including both 3-dimensional (3D) TOF (Voxel dimension: 0.6 x 0.5 x 0.9 mm in 5 minutes and 40 seconds) and 3D CE-MRA (voxel dimension: 0.7 x 0.7 x 0.8 mm in 20 seconds, using parallel acquisition with an acceleration factor of 4). CTA images were acquired on a 16-slice CT scanner (voxel dimension: 0.35 x 0.35 x 0.8 mm in 17 seconds). The image quality and visualization of up to 26 intracranial arterial segments in each study was evaluated by 2 experienced radiologists. The arterial diameter for selective intracranial arteries was measured independently on each of the 3 studies, and statistical analysis and comparative correlation was performed. RESULTS: A total of 312 arterial segments were examined by CE-MRA, TOF-MRA, and CTA. The majority of intracranial arteries (87%) were visualized with diagnostic image quality on CE-MRA with a significant correlation to TOF (R values = 0.84; 95% confidence interval 0.79-0.86, P < 0.0001), and to CTA (R values = 0.74; 95% confidence interavl 0.68-0.78, P < 0.001). The image quality for small intracranial arteries, including the anterior-inferior cerebellar artery, the posterior communicating artery, and the M3 branch of the middle cerebral artery, was significantly lower on CE-MRA compared with TOF and CTA (P < 0.03). There was a significant correlation for the dimensional measurements of arterial diameters at CE-MRA with TOF (r = 0.88, 95% confidence interval 0.81-0.93), and CTA (r = 0.83, 95% confidence interval 0.73-0.90). CONCLUSION: The described 3 T CE-MRA protocol, spanning from the cervical to the intracranial vessels, visualized and characterized the majority of intracranial arteries with image quality comparable with that obtained using TOF-MRA and CTA. Further clinical studies are required to establish the accuracy of the technique in a broader clinical setting.

Adult↗
PubMed1984

Diagnosis of cavernous haemangiomas by computed tomography and angiography.

Computed tomography and angiographical findings of cavernous haemangiomas of the brain are reported on the basis of six cases of the authors, and a review of the literature. Computed tomography showed well demarcated, round densities with tiny calcifications, and mild contrast enhancement (0-25 HU), with no mass effect and with open sulci round the lesion. The angiographical findings were normal except in one patient with an early draining vein and in another with a late draining vein; consequently an injection of at least 10 to 15 ml of contrast medium, and a prolonged angiographical series are recommended. According to the literature, capillary blush may also be seen in angiography. If both CT and angiography are used the diagnosis is definitive, and a neoplasm can be excluded. In five of our patients the diagnosis was verified surgically and histologically, while the sixth patient was not operated on because the frontoparietal lesion was near the motor region. In most cases, surgical removal is easy and successful.

Adult↗
PubMed1992

[The magnetic resonance of small hepatocarcinoma. A comparison with echography, computed tomography, digital angiography and computed tomography with lipiodol].

Diagnostic techniques as a whole and periodic ultrasonography (US) in particular frequently allows tumors < 3 cm (small hepatocellular carcinomas) to be detected in patients suffering from liver cirrhosis. Multifocal diseases are a major limitation to surgery. Recently, MR imaging has shown its capabilities in the diagnosis of small hepatocellular carcinomas. In our study the diagnostic value of MR imaging was compared with that of US, of pre- and post-contrast CT, of digital angiography and of CT after lipiodol injection (Lipiodol CT). The morphologic and signal intensity MR features of small hepatocellular carcinomas were investigated. Fifteen cirrhotic patients with 31 nodules of hepatocellular carcinoma < 3 cm were examined. All patients were studied with US, MR imaging, angiography and Lipiodol CT; 12/15 patients underwent CT. Histologic confirmation was obtained in 12 nodules (2 at surgery and 10 by means of percutaneous biopsy); in the extant 19 cases the diagnosis was made by combining US, CT, MR, angiographic and lipiodol-CT findings; in 9 tumors < 1 cm Lipiodol retention one month after angiography was considered as diagnostic. MR imaging detected 21/31 nodules (63%), US 22/31 (66.6%), CT 12/24 (50%), angiography 24/31 (74%), lipiodol CT 29/31 (92.5%). Mc Nemar test showed no difference in sensitivity between MR imaging and CT, MR and angiography, MR and US, lipiodol CT and angiography; however, the differences between the detection rates of MR imaging and Lipiodol CT and CT and lipiodol CT and US were statistically significant (p < 0.05). The difference in sensitivity between the detection rates of lipiodol CT and US was just above the threshold value which is usually considered significant (p = 0.065). One false positive was observed on US and none with MR, CT, angiography and lipiodol CT. On Se T1-weighted images 18 nodules were hyperintense, 2 isointense and 2 hypointense; on proton-density images 14 nodules were hyperintense, 7 isointense and none hypointense. On SE T2-weighted images 18 nodules were hyperintense, 3 isointense and none hypointense. A pseudocapsule was seen in 10/17 nodules (58%), especially on T1-weighted images. Accuracy and limitations of each technique and morphologic and signal intensity MR findings of small hepatocellular carcinoma are discussed. We believe that US is still the best diagnostic technique for the screening of hepatocellular carcinomas in cirrhotic livers.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed2004

Multidetector computed tomography angiography of the abdomen.

Multidetector computed tomography (MDCT) angiography has provided excellent opportunities for advancement of computed tomography (CT) technology and clinical applications. It has a wide range of applications in the abdomen including vascular pathologies either occlusive or aneurysmal; enables the radiologist to produce vascular mapping that clearly show tumor invasion of vasculature and the relationship of vessels to mass lesions. MDCTA can be used in preoperative planning for hepatic resection, preoperative evaluation and planning for liver transplantation. MDCTA can also provide extremely valuable information in the evaluation of ischemic bowel disease, active Crohn disease, the extent and location of collateral vessels in cirrhosis.

Angiography↗