Differentiation of alveolitis and pulmonary fibrosis in rabbits with magnetic resonance imaging after intrabronchial administration of bleomycin.

RATIONALE AND OBJECTIVES: The authors investigate the ability of magnetic resonance imaging to differentiate alveolitis and pulmonary fibrosis by correlating magnetic resonance and pathologic findings. METHODS: Lung damage was induced in 52 rabbits by instillation of 5 mL bleomycin sulfate (10 mg/kg) into a lower-lobe bronchus using a balloon catheter. Magnetic resonance examinations were performed in a group of 7 animals 3 hours after the initial damage, and in groups of 8 animals 24 hours and 8, 14, 30, and 80 days after the initial damage. Control animals were examined 3 hours (n = 5), 24 hours, and 8 days (n = 3 for each), respectively, after the instillation of 5 mL 0.9% sodium chloride. Magnetic resonance imaging at 1.5 T included conventional T1-weighted sequences before and after injection of gadolinium-DTPA (0.1 mmol/kg), and T2-weighted fast spin echo sequences. The signal intensity and contrast enhancement of injured lung were evaluated and compared with the contralateral healthy lung and with the lungs of control animals. All animals were killed immediately after the magnetic resonance examination, and the lungs were removed and fixed before sectioning and staining. RESULTS: There was good correlation between signal intensity and contrast enhancement with magnetic resonance imaging and histologic examination. The early phase of acute alveolitis showed lesions with high signal intensity on both T1- and T2-weighted images and marked contrast enhancement after gadolinium-DTPA administration, whereas in the late fibrotic stage the lesions displayed significantly lower signal intensity and contrast enhancement. CONCLUSION: Magnetic resonance imaging can differentiate between alveolitis and fibrosis by means of signal intensity and contrast enhancement after gadolinium-DTPA administration.

Pulmonary nodules: detection with low-dose vs conventional-dose spiral CT.

The purpose of the study was the evaluation of low-dose spiral CT in the detection and assessment of contours of pulmonary nodules. In a prospective investigation 71 consecutive chest CT examinations were acquired both at 30 and 200 mA. Films were interpreted independently by two radiologists. According to the size, nodules were divided into four categories: 10 mm; nodule shape was registered. With both protocols, 240 nodules were detected. The correlation coefficient for both methods was 0.89. Discrepancies were found most frequently in nodules near to pulmonary vessels. Nodule size estimation did not differ more than one size category. Eight spiculated nodules were identified by both techniques. Low-dose spiral CT of the chest has a high sensitivity in the detection of pulmonary nodules. If clinical circumstances require dose minimization, low-dose spiral CT may be advocated as an alternative screening method to conventional dose spiral CT.

[Comparison of radiological procedures in preoperative assessment of anchorage strength of spinal implants]. / Vergleich radiologischer Verfahren zur präoperativen Beurteilung der Verankerungsfestigkeit von Wirbelsäulenimplantaten.

PURPOSE: To compare three techniques with regards to their ability to estimate pull out strength of spinal fusion hardware. MATERIAL AND METHODS: VDS-screw fixation strength in 50 human cadaveric vertebral bodies was approximated by means of pull out force measurement. Bone quality was assessed by Dual X-ray Absorptiometry (DXA). Quantitative Computed Tomography (QCT) and T2*-relaxation time. For each of these techniques, correlation with axial pull out force strength was investigated. RESULTS: Highest correlation was found for cancellous bone density measured by QCT (r = 0.72; p < 0.001). Immediately followed by DXA (r = 0.70; p < 0.001), which involves all bone components. Inverted T2*-relaxation time (r = 0.55; p < 0.001) and cortical bone density (QCT) correlated just slightly with pull-out force strength. CONCLUSIONS: Absorptiometrical techniques like QCT and DXA are most appropriate to estimate VDS-screw fixation strength preoperatively.

Non invasive evaluation of the inflammatory activity in sarcoidosis with high-resolution computed tomography.

PURPOSE: The value of high resolution computed tomography (HR-CT) in the recognition of pathologic changes of the lung parenchyma, especially in the diagnosis of sarcoidosis, is well established. The importance of these findings in regard to the inflammatory activity is not sufficiently documented, also because a direct histologic correlation is seldom possible. METHOD: In a prospective study twenty-one patients with suspected or known sarcoidosis were evaluated. The diagnostic work up comprised the clinical examination, lung function tests, the radiological evaluation, including GH-CT, and bronchoscopy for bronchoalveolar lavage (BAL) and transbronchial biopsy. RESULTS: The comparison of the HR-CT findings, like pathologic appearance of the bronchovascular bundle and intraparenchymal nodules, with serologic and BAL-parameters yielded high correlation coefficients with the total cell count in BAL and sIL-2R, and moderate correlations with the lavage lymphocyte count and the activity markers, like T4/T8 ratio, IL-2R and HLA-DR expression. CONCLUSION: As a non invasive method, HR-CT depicts pathologic findings of the lung parenchyma which are associated with the inflammatory activity of sarcoidosis.

[CT angiography in arterial occlusive disease: comparison of 3 rendering techniques]. / CT-Angiographie bei arterieller Verschlusskrankheit: Vergleich von 3 Rekonstruktionsverfahren.

PURPOSE: To evaluate different rendering techniques of CT data for the assessment of long vessel segments in peripheral vascular occlusive disease. MATERIAL AND METHODS: 40 CT angiograms (aortoiliac: n = 20, leg arteries: n = 20) were viewed using three different rendering techniques: 1, maximum intensity projection (MIP); 2, volume rendering (VR); 3, shaded surface display (SSD). CT angiograms were obtained in 6 or 8 projections. Axial cross-section images were analysed using an interactive cine mode. Intraarterial DSA was the standard in all cases. RESULTS: The sensitivities for the diagnosis of occlusive disease were 100% (cross-section images), 94% (MIP), 91% (VR) and 93% (SSD). The specificities were 100%, 99%, 99% and 99%, respectively. For the accurate grading of high-grade (> 75%) stenoses, the sensitivities were 85% (cross-section images), 62% (MIP), 44% (VR) and 35% (SSD). Specificity was 99% for all techniques. CONCLUSIONS: CTA is accurate in occlusive disease. Interactive viewing of cross-section images is the most accurate technique. MIP is superior to VR in the imaging of high-grade stenoses because contrast-to-noise ratio is high and thresholding is not necessary.

Prospective comparison of CT angiography of the legs with intraarterial digital subtraction angiography.

OBJECTIVE: The aim of this study was to determine the accuracy of CT angiography (CTA) with a single spiral acquisition for the diagnosis of arterial stenoses and occlusion in patients with peripheral vascular occlusive disease. SUBJECTS AND METHODS: In a prospective study, intraarterial digital subtraction angiography and i.v. CTA from the groin to the lower calves were performed on 50 patients with vascular occlusive disease. Maximum-intensity-projection images in multiple views were produced. The accuracy of CTA with and without analysis of the axial scans was determined with digital subtraction angiography as the standard. RESULTS: The sensitivities of CTA were 100% for the diagnosis of femoral artery occlusion, 100% for the detection of popliteal artery (including tibial-peroneal arterial trunk) occlusion, and 94% for the detection of tibial artery occlusion. The specificities were 100%, 99%, and 98%, respectively. When maximum-intensity-projection images were interpreted without axial scans, sensitivities were 98%, 85%, and 92% and specificities were 100%, 99%, and 97%, respectively. For the accurate grading of high-grade (75-99%) stenoses of the superficial femoral artery and the popliteal artery (including tibial-peroneal arterial trunk), the sensitivities of CTA were 88% and 73% and the specificities were 94% and 100%, respectively. When maximum-intensity-projection images alone were used, the sensitivities for the correct grading of high-grade stenoses were 58% and 36% and the specificities were 99% and 100%, respectively. CONCLUSION: CTA from the groin to the lower calves is feasible, and the short examination time is a significantly advantage over the time required for other noninvasive techniques. CTA is particularly accurate in the depiction of femoral artery occlusions. Maximum-intensity-projection images are useful, but analysis of axial scans is more accurate for the grading of arterial stenoses. The results of CTA are encouraging enough to warrant further studies. A CTA protocol covering the pelvic and pedal vessels remains to be established and evaluated.

[CT and MRI in malignant peripheral neuroectodermal tumors]. / CT und MRT bei malignen peripheren neuroektodermalen Tumoren.

To evaluate the diagnostic accuracy of CT and MRI in the diagnosis of malignant peripheral neuroectodermal tumors (MPNT), the imaging data of nine patients with immunehistochemically proven MPNT were retrospectively analyzed. The average age was 24 years (ranging from 5 to 63 years). MRI and CT of all patients showed large tumors with direct infiltration of the surrounding structures. Intratumoral calcifications were not identified. All tumors showed equal to less high signal intensity in T1- and high signal intensity in T2-weighted images. Because of its high soft-tissue contrast, MRI is the most capable imaging modality in the diagnosis and therapy-monitoring in these tumors.

[Osseous manifestations of Bourneville-Pringle disease]. / Ossäre Manifestationen des M. Bourneville-Pringle.

Tuberous sclerosis (Bourneville-Osseous Manifestations of Bourneville-Pringle's Disease) is a rare disease characterised by the clinical traid of epilepsy, mental retardation and adenoma sebaceum. In addition of this triad a number of patients shows other visceral, neurocutaneus or osseous manifestations. We describe the radiological findings of two patients with typical skeletal changes.

Malignant peripheral neuroectodermal tumors in urology.

During the past few years, a new tumor type has emerged in the pediatric and adolescent group of cancer patients, which has been designated malignant peripheral neuroectodermal tumor (MPNT). This tumor has some clinical and pathological signs in common with either soft-tissue sarcomas or classic Ewing's sarcoma, but is defined as a distinct entity because of its immunohistological characteristics. The tumor expresses neuronal markers, but the pattern varies: chromogranin, neuron-specific enolase, synaptophysin, protein S-100 and others. MPNT can occur in the urogenital region. The differential diagnosis on clinical grounds must include Ewing's and soft tissue sarcomas, and also Wilms' tumor and its variants. MPNT are often wide spread in the urogenital region when first diagnosed. Response to radiotherapy and combination chemotherapy is limited. Radical surgery is not always possible. The prognosis therefore remains rather poor at this time. A selection of MPNT patients is presented to demonstrate the various problems associated with this diagnosis. MRI and CT of all patients showed large tumors with direct infiltration of the surrounding structures. MRI is the best imaging modality for diagnosis and therapy monitoring in these tumors, because of its high soft-tissue contrast.