Radiographic techniques for balloon-occlusion pulmonary angiography.

Pulmonary angiography was performed in 125 patients with suspected pulmonary embolism. Standard angiographic techniques were combined with balloon occlusion of pulmonary arterial branches using a double lumen catheter and contrast material injection distal to the occlusion. Vessel opacification was fluoroscopically monitored and images obtained with either a conventional cut-film camera, a spot-film camera, or cineangiography. Balloon-occlusion angiography improved image quality and contributed substantially to the radiographic diagnosis of pulmonary embolism in most patients. The technique is useful in patients too ill to undergo conventional angiography and may be performed at the bedside.     

Spiral CT angiography of renal arteries: comparison with angiography

A prospective study was carried out to determine the accuracy of spiral CT angiography (CTA) in the detection of renal artery stenosis (RAS). Eighty-two patients with arterial hypertension underwent CTA and digital subtraction angiography (DSA) to exclude RAS. For CTA a contrast medium bolus of 100–150 ml (flow rate 3 ml/s) was injected. A 24 or 40 s CTA was started at the origin of the superior mesenteric artery after a delay time determined by test bolus injection (collimation = 2 mm, pitch = 1/1.5). For stenosis detection transverse images supported by maximum intensity projections (MIP) or multiplanar reconstruction projections were used. Of 197 renal arteries examined (including 33 accessory arteries), 34 RAS were visualized using DSA. With CTA, one hemodynamic RAS was missed and one additional hemodynamic RAS was found. Sensitivity/specificity was calculated to be 94 %/98 %. For hemodynamically relevant RAS (> 50 %) the sensitivity/specificity was 96 %/99 %. CTA additionally depicted five adrenal masses. The high accuracy rate of RAS detection thus allows the use of CTA as a screening method in patients with arterial hypertension to exclude a renovascular cause. Received: 23 June 1997; Revision received: 6 January 1998; Accepted: 29 April 1998     

Improved vascular opacification in cerebral computed tomography angiography with 80 kVp

PURPOSE: We sought to intraindividually compare computed tomography angiographies (CTAs) acquired at 80 kVp and 120 kVp with respect to vessel contrast, noise level, and radiation dose. MATERIAL AND METHODS: CTA was performed on a single-slice CT scanner using tube voltages of 80 kVp and 120 kVp in 29 patients with arteriovenous malformations. Mean Hounsfield Units (HU) were evaluated for different vessels and brain parenchyma. To determine contrast-to-noise ratios (CNRs), noise levels were estimated from phantom measurements. RESULTS: The calculated effective dose to male/female patients was 0.4/0.5 mSv for 80 kVp and 0.7/0.8 mSv for 120 kVp. CT density in blood vessels was between 297 and 458 HU for 80 kVp and 152 and 229 HU for 120 kVp (P<0.0001). Despite an increased noise level in the low-voltage images, the CNR was 26-59% higher at 80 kVp than at 120 kVp (P<0.05). CONCLUSION: The use of a reduced tube potential leads to improved CNR in CTA of the cerebral vasculature and a markedly reduced radiation exposure to patients.     

Selective angiography of the external and internal carotid arteries in the diagnosis of supra-tentorial meningiomas

Summary From a study of 85 supratentorial meningiomas, the Authors draw the following conclusions: 1. Angiography of the internal carotid is the examination of choice in anterior fossa meningiomas supplied by branches of the ophthalmic artery. — 2. Angiography of the external carotid is very valuable in meningiomas of the convexity. — 3. An area of newly-formed pathological vessels on the external carotid angiography is indicative, however not pathognomonic, of a meningioma.

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Selektive Angiographie der Arteria carotis externa und Arteria carotis interna bei supratentoriellen Meningeomen

Zusammenfassung Die Verfasser berichten über die arteriographischen Untersuchungsbefunde von 85 supratentoriellen Meningeomen. Sie kommen zu dem Ergebnis, daß bei den Meningeomen der vorderen Schädelgrube eine selektive Angiographie der A. carotis interna durchgeführt werden sollte. Bei Meningeomen der Konvexität muß eine Angiographie der A. carotis externa erfolgen, da in einem Teil der Fälle nur dadurch eine Gefäßanfärbung des Tumors erreicht werden kann. Es wird darauf hingewiesen, daß es jedoch auch Gliome gibt, die von der A. carotis externa mit Blut versorgt werden. In diesen Fällen hat der Tumor eine enge Verbindung zur Dura.

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Le diagnostic des méningiomes sustentoriels par l'angiographie sélective des artères carotides externe et interne

Résumé 1. L'angiographie sélective de l'artère carotide interne est déterminante lorsqu'il s'agit de méningiomes de la fosse antérieure, alimentés par les branches méningées de l'artère ophtalmique. — 2. L'angiographie carotidienne externe est très utile pour le diagnostic des méningiomes de la convexité. — 3. Le diagnostic de méningiome n'est certain que lorsqu'il y a des modifications typiques des branches méningées.

     

Intracranial aneurysmal rupture and ventricular opacification during carotid angiography

A case of intra-angiography rupture of an aneurysm, a rarity, is reported. It was confirmed by CT Scan and autopsy. The aneurysm ruptured despite taking all precautions recommended in the literature. This complication may be reduced by the use of non-ionic contrast media and slow flow rate injections.     

颅内动脉CTA的前瞻性研究

目的：评价和研讨CTA对脑动脉的显示能力及扫描技术。材料和方法：脑MIP—CTA检查正常的患者50例。将CTA对颅内主要动脉的显示率与柳氏测得的MRA的类似数据进行比较。结果：对较粗大的动脉分支，CTA和MRA均显示良好。CTA对细小动脉分支的显示不及粗大动脉，差别较大。对前交通动脉的显示率，CTA明显高于MRA。CTA最佳延迟扫描时间的个体差异较大。结论：CTA能高质量地显示脑动脉，是评价脑血管状况，对脑血管疾病进行诊断和筛选的好方法。选择恰当的扫描参数很重要。CTA前有必要行小剂量试验。     

Carotid arteries: evaluation with low-field-strength MR angiography.

Magnetic resonance (MR) angiography of neck vessels was performed with a 0.2-T permanent magnet by using a two-dimensional, time-of-flight technique. Thirty-one patients were included in the study. The imaging parameters used included a repetition time of 60 msec, an echo time of 10 msec, a 90 degrees flip angle, and a 192 x 256 matrix; 40-50 sequential two-dimensional sections were acquired through the neck. Stenosis was graded on a scale of 1-5. Correlation of digital and MR angiography was made in the clinically nonrelevant cases (stenoses of grades 1 and 2), with overestimation to grade 3 in six cases. Two grade 3 stenoses were overestimated as grade 4. Severe stenoses were correctly characterized in all but one case, which was underestimated because of a segmental short extension of the stenotic lesion. Obstructions were found in two cases. Areas with a lack of signal were observed in four patients with severe stenosis and in two with tortuous arteries. Correct diagnosis, however, was achieved with analysis of the maximum intensity projection animation display. Low-field-strength MR angiography has the same clinical value as that performed with high field strengths.     

MR angiography of the renal arteries

During, the past decade. MRA has evolved from an cxperimental technique into the modality of choice for the noninvasive evaluation of renovascular disease. The recent widespread application of MRA for these indications has been driven primarily by the advent of 3D contrast-enhanced MRA. which provides a fast, reliable technique for imaging large vascular territories and generates images, after postprocessing, similar in appearance to digital subtraction angiography. The cross-sectional volumetric nature of contrast-enhanced MRA affords some advantages over conventional catheter angiography. Although 3D contrast-enhanced MRA forms the backbone of vascular MR studies, several adjunctive sequences are employed to maximize the diagnostic yield of the examination. For example. flow-dependant imaging is used to complement the morphologic images of contrast-enhanced MRA by providing hemodynamic information. As such, MRA is unique among noninvasive imaging modalities in that it offers a comprehensive evaluation of anatomy and function. The availability and reliability of MRA extend renal artery screening to a wider spectrum of patients. Current applications of renal MRA range from detection of renal artery stenosis to evaluation for renal transplant donors.     

Fibromuscular dysplasia of renal arteries: comparison of intravenous digital subtraction angiography with conventional angiography

Intravenous digital subtraction angiography (IV-DSA) was compared with conventional arteriography (CA) in 14 patients with fibromuscular dysplasia (FMD) of at least one renal artery. IV-DSA identified 29 of the 34 renal arteries detected by CA. A diagnostic quality IV-DSA examination was obtained in 23 of 29 renal arteries (78%). In adequately imaged renal arteries, IV-DSA correctly identified 12 of 20 FMD renal arteries, misdiagnosed 8 FMD renal arteries as normal and correctly identified 3 normal renal arteries. These poor results, due to poor spatial resolution and subtraction artifacts inherent in the IV-DSA system, warrant careful interpretation of negative examinations and further evaluation of high risk patients.     

Non-invasive evaluation of the visceral arteries with magnetic resonance angiography

Traditionally, there have been only a few indications for imaging of the visceral arteries. With improvements in treatment of many mesenteric vascular disorders, it has become more important to establish a diagnosis early in the course of the disease. With the advent of ultrasound, computed tomography and magnetic resonance imaging non-invasive imaging of the visceral arteries became possible, although all these modalities were limited in scope for demonstration of mesenteric pathology. The advent of high-quality mesenteric MR arteriography and venography, which allows comprehensive evaluation of both visceral artery anatomy and function, has led to a huge increase in the number of studies directed at the mesenteric arteries in many departments.