Detection of pulmonary nodules at spiral CT: comparison of maximum intensity projection sliding slabs and single-image reporting.

The aim of this study was to compare numbers of pulmonary nodules detected with maximum intensity projections using a slab thickness of 15 mm (MIP 15) and 30 mm (MIP 30) with single image (SI) presentation of chest CT scans. Two readers reviewed MIP 15, MIP 30, and SI presentations of 10-mm (n = 8) and 5-mm collimation (n = 10) helical CT scans and recorded size, location, and diagnostic confidence (definite, probable) of pulmonary nodules. Readers 1 and 2 recorded more nodules with MIP 15 than with SI: 10-mm collimation, 77/64 and 60/56; 5-mm collimation, 64/60 and 40/36; and more "definite" nodules (10-mm collimation: 68/57 and 51/42; 5-mm collimation: 43/36 and 34/30). MIP 15 also detected more nodules than MIP 30 at 10-mm collimation: 77/72 and 60/50; with no major differences at 5-mm collimation: 64/66 and 40/38; and more "definite" nodules (10-mm collimation: 68/58 and 51/36; 5-mm collimation: 43/39 and 34/29). There were only minor differences between SI and MIP 30. Reading time and image number per study were reduced with MIP presentations by a factor of 1.4-5.3. There were no significant differences in the number of nodules detected with SI, MIP 15, and MIP 30, but MIP presentation reduced reporting time and filming cost when compared with SI reporting. For detection of nodules MIP 15 was slightly superior to MIP 30.

Spiral CT of pulmonary nodules: interobserver variation in assessment of lesion size.

The aim of this study was to assess interobserver variability in size determination of pulmonary nodules at spiral CT. Twenty-three patients with known pulmonary nodules (diameter 2-40 mm, mean diameter 7 mm) underwent spiral chest CT (collimation 5 mm, pitch 1). Images were reconstructed at 3- and 5-mm intervals (RI). Hard copies were analyzed by two radiologists who recorded every nodule with regard to location, diagnostic confidence ("definite," "probable") and nodule size in increments of 1 mm with specific attention to correct classification into one of three size classes (< or = 5 mm, 6-10 mm, > 10 mm). Interobserver variability was determined with Pearson's correlation coefficient and kappa measure. Of a total of 286 nodules, 103 nodules were found accordingly by both readers at 3 mm RI, and 96 at 5 mm RI. There was a good correlation of measurements (in millimeters) between both readers (Pearson's correlation coefficient: 0.89-0.95). Interobserver variability in categories was good at both reconstruction intervals (kappa: 0.61 at 3 mm, 0.74 at 5 mm RI) and very good (0.81) at 5 mm RI when uncertain nodules were excluded. Spiral CT allows reproducible size determination of pulmonary nodules as shown by good interobserver agreement in exact size measurement and categorization into three size classes.

Detection of pulmonary nodules with overlapping vs non-overlapping image reconstruction at spiral CT.

The aim of this study was to analyze whether overlapping image reconstruction increases numbers of pulmonary nodules detected at helical CT. Forty-eight helical CT scans (21 with a slice thickness of 10 mm; 27 with a slice thickness of 5 mm) of patients with known pulmonary nodules were reconstructed both with overlapping and non-overlapping image reconstruction. Two readers recorded number and size of pulmonary nodules as well as diagnostic confidence. With overlapping image reconstruction each reader diagnosed more pulmonary nodules (slice thickness 10 mm: +24.0 and +26.7%, both p < 0.01; slice thickness 5 mm: +9.5 and +11.9%, both not significant) and more "definite" nodules (slice thickness 10 mm: +20.3%, p < 0.05, and +30.8%, p < 0.005; slice thickness 5 mm: +18.0 and +17.0%, both p < 0.05). Nodules diagnosed with overlapping image reconstruction only were almost exclusively smaller than the slice thickness. The increase in number of nodules detected was not associated with a decrease in diagnostic confidence. Overlapping image reconstruction improves detection of pulmonary nodules smaller than the slice thickness at spiral CT.

Metabolic characterization of AIDS dementia complex by spectroscopic imaging.

Prospective proton chemical shift imaging (CSI) of the brain was performed in 30 HIV- 1-seropositive patients and 11 healthy controls. Significant (P < 0.05) reductions in the N-acetyl-L-aspartate (NAA)/total creatine (Cr), and NAA/total choline (Cho) ratios and significant increases in Cho/Cr occurred in patients with 1) AIDS-defining diagnoses; 2) <200 CD4 lymphocyte counts/microl; 3) neurological evidence for an AIDS dementia complex (ADC); 4) magnetic resonance imaging (MRI) signs of cerebral atrophy. The basal ganglia and the insula were affected to approximately the same extent and without indications of spatial variations within these areas. Reduced NAA seems to indicate progressive neuronal injury or loss due to productive HIV infection in the brain and its clinical picture ADC. Spectroscopic abnormalities were, however, also observed in neurologically normal HIV patients or those with normal MRI results. Proton CSI may therefore serve as an early quantitative marker of central nervous system involvement in AIDS.

Helical CT of pulmonary nodules in patients with extrathoracic malignancy: CT-surgical correlation.

OBJECTIVE: Our aim was to assess the sensitivity of helical CT for revealing pulmonary nodules. Thoracotomy with palpation of the deflated lung, resection, and histologic examination of palpable nodules was used as the gold standard. SUBJECTS AND METHODS: Thirteen patients underwent helical CT (slice thickness, 5 mm; reconstruction intervals, 3 mm and 5 mm; interpreted by two independent observers). Subsequently, patients underwent unilateral (n = 6) or bilateral (n = 7) surgical exploration, and CT-surgical correlation of 20 lungs was performed. RESULTS: Ninety nodules were resected (61 were smaller than 6 mm; 13 were 6-10 mm; 11 were larger than 10 mm; in five nodules, the size was not recorded at surgery). Sixty-nine nodules were located in the pulmonary parenchyma and 21 in the visceral pleura. Of the 90 lesions, 43 (48%) were found on histology to represent metastases. For lesions detected by at least one observer, the sensitivity of helical CT was 69% for intrapulmonary nodules smaller than 6 mm, 95% for intrapulmonary nodules larger than or equal to 6 mm, and 100% for histologically proven intrapulmonary metastases larger than or equal to 6 mm. For lesions smaller than or equal to 10 mm, sensitivity was better using a reconstruction interval of 3 mm rather than of 5 mm. CONCLUSION: In this study, the sensitivity of helical CT exceeded the sensitivity of conventional CT in previous reports. However, because of limitations in the detection of intrapulmonary nodules smaller than 6 mm and of pleural lesions, complete surgical exploration should remain the procedure of choice in patients undergoing pulmonary metastasectomy. Preoperative helical CT should be used to guide the surgeon to lesions that are difficult to palpate.

Intracranial vascular stenosis and occlusion: comparison of 3D time-of-flight and 3D phase-contrast MR angiography.

We compared the value of 3D time-of-flight (TOF) and phase-contrast (PC) MR angiography (MRA) for detection and grading of intracranial vascular steno-occlusive disease. Unenhanced 3D-TOF MRA and 3D-PC MRA (30-60 cm/s velocity encoding) were performed at the level of the circle of Willis in 18 patients, mean age 56 +/- 10 years. Postprocessed images using a maximum-intensity projection reconstruction with multiple targetted projections were analysed. A total of 126 vessels was assessed by PC MRA and 143 by TOF MRA, with digital subtraction angiography (DSA) in 15 patients and/or transcranial Doppler sonography (TCD) in 18 as a standard. Two blinded readers reviewed the MRA, DSA and TCD examinations retrospectively. On DSA and/or TCD the two observers found 32 and 28 steno-occlusive lesions. 3D-TOF MRA was more sensitive than 3D-PC MRA (87% and 86% vs. 65% and 60%) and had a higher negative predictive value (96% vs. 89%). Correct grading of stenoses was achieved in 78 % by 3D-TOF and 65% by 3D-PC MRA.

Breath-hold gadolinium-enhanced MR angiography of the major vessels at 1.0 T: dose-response findings and angiographic correlation.

PURPOSE: To find the appropriate contrast agent dose for gadolinium-enhanced magnetic resonance (MR) angiography by using individual measurement of contrast agent transit times in a randomized study. MATERIALS AND METHODS: A total of 34 patients with disease of the aorta or its major branches or both were randomly assigned to receive a dose of 0.1, 0.2, or 0.3 mmol of gadopentetate dimeglumine per kilogram of body weight. Initially, contrast agent transit times were measured with use of a turbo fast-low-angle-shot sequence. Subsequently, a three-dimensional fast imaging with steady-state precession sequence (7.3-msec repetition time, 2.8-msec echo time) was used for breath-hold MR angiography. Gadopentetate dimeglumine was injected with an MR-compatible power injector. Efficacy was evaluated by measurement of vessel enhancement and by clinical correlation of MR angiograms with x-ray angiograms. RESULTS: Evaluation of contrast agent transit time was possible in all patients with the test doses, which provided contrast-enhanced MR angiograms of constant quality. Neither vessel enhancement nor diagnostic information was significantly different across the these study groups. CONCLUSION: The clinical gadolinium dose of 0.1 mmol/kg is sufficient for diagnostic assessment of the aorta and its major branches at contrast-enhanced MR angiography. High-dose studies appear not to be required for these large vessels.

[The color Doppler-guided compression therapy of pseudoaneurysms. The authors' own experiences and a review of the literature]. / Farb-Doppler-gesteuerte Kompressionstherapie von Pseudoaneurysmen. Eigene Erfahrungen und Literaturübersicht.

PURPOSE: The common use of interventional angiographic techniques and the sensitive detection of this vascular complication by ultrasound are major factors contributing to the increasing incidence of femoral artery pseudoaneurysms. ultrasound-guided compression repair of femoral artery pseudoaneurysms was prospectively evaluated. MATERIAL AND METHODS: 11 femoral artery pseudoaneurysms were detected in 10 patients who ranged from 45 to 79 years of age. In one patient two ipsilateral pseudoaneurysms occurred. All patients were considered to be candidates for ultrasound-guided compression repair. RESULTS: Successful compression repair was achieved in 9 of 11 pseudoaneurysms (82%) with a mean diameter of 2.2 +/- 1.0 cm. In two recurrent lesions (22%) definitive thrombosis required a second treatment. Compression was maintained between 10 and 40 minutes (mean 22 +/- 11 minutes). No complications have been observed. CONCLUSIONS: Ultrasound-guided compression repair provides an efficient, noninvasive and safe treatment of femoral artery pseudoaneurysms. More than 80% of pseudoaneurysms can be occluded successfully. In recurrent lesions a second attempt is valuable.

[The value of 3-phase spiral CT and magnetic resonance tomography in preoperative diagnosis of pancreatic carcinoma]. / Die Wertigkeit der 3-Phasen-Spiral-CT und der Magnetresonanztomographie in der präoperativen Diagnostik des Pankreaskarzinoms.

UNLABELLED: The purpose of this study was to assess the role of spiral computed tomography (SCT) and magnetic resonance imaging (MRI) in the preoperative work-up of patients with pancreatic carcinoma, regarding local resectability and vascular involvement. METHODS AND MATERIALS: A total of 28 patients (19 men and 9 women; mean age 58 years) with known or highly suspected carcinoma of the pancreas were included in this study. All patients prospectively underwent MRI ( +/- gadolinium-DTPA ) and SCT (3-phase examination) as preoperative diagnostic imaging studies, and laparotomy was carried out within 7 days, irrespective of the MRI or SCT findings. SCT and MR studies were reviewed independently by two radiologists, without knowing the results of the surgical exploration. Standardized image analysis was correlated with findings at laparatomy. RESULTS: Laparotomy identified 10 patients to be suitable for surgical resection and 18 pancreatic carcinomas to be unresectable. In 17 of 18 non-resectable carcinomas MRI and SCT were able to obtain correct information about unresectability (sensitivity 94%), in 7 (MRI), resp. 8 (SCT) carcinomas were correctly considered to be resectable (sensitivity 70% of MRI and 80% for SCT). The presence of vascular involvement was depicted by SCT with a sensitivity of 82-100% and 62-100% by MRI. The specificity varied between 85-100% for SCT and 77-100% for MRI. CONCLUSION: Both MRI and SCT are good techniques for the preoperative work-up of pancreatic carcinomas in order to obtain a correct assessment of local resectability.

[Pulmonary varicose veins. Case report and review of the literature]. / Pulmonalvenenvarikose. Fallbeschreibung und Literaturübersicht.

Pulmonary varicosis is a rare, presumably congenital localized dilatation of a pulmonary vein which is often associated with cardiac disease. We describe a case featuring enlargement of a pulmonary varix after mitral valve replacement, caused by mitral regurgitation, and discuss diagnostic possibilities, differential diagnosis and various development of this vascular malformation. A detailed review of the literature is given.