The purpose of this study was to describe the 3He MRI findings of normal pulmonary ventilation in healthy volunteers and to evaluate abnormalities in patients with different lung diseases. Hyperpolarized 3He gas (300 ml, 3 x 10(5) Pa, polarized to 35-45% by optical pumping, provided in special glass cells) was inhaled by 8 healthy volunteers and 10 patients with different lung diseases. Imaging was performed with a three-dimensional fast low-angle shot (FLASH) sequence (TR = 11.8 msec; TE = 5 msec; transmitter amplitude, 5-8 V; corresponding flip angle, < 5 degrees) in a single breath-hold (22-42 seconds). Clinical and radiological examinations were available for correlation. The studies were performed successfully in eight of eight volunteers and in 8 of 10 patients. The lung parenchyma of volunteers with normal ventilatory function exhibited rather homogeneous intermediate to high signal, whereas patients with chronic obstructive lung disease or bronchiectasis presented with severe signal inhomogeneities with patchy or wedge-shaped defects. The mass effect of bronchogenic carcinoma, chronic empyema, lymphadenopathy, or pleural effusion caused large signal defects, representing the lesion and adjacent hypoventilation, the extent of which had not been presumed from chest x-ray or CT. 3He MRI is a promising new modality for the assessment of pulmonary ventilation and its abnormalities. Additional studies are needed to determine its potential clinical role.

Adult↗

PubMedDate not supplied

CT after enucleation of renal cell carcinoma.

Computed tomography (CT) was performed in 28 patients 2 weeks to 120 months after enucleation of renal cell carcinoma. The postoperative defect could be exactly localized in all patients. A wedge-shaped (N = 11) or concave (N = 9) morphology was typical. No dependence between morphology of the defect and localization or size of the tumor or the operative technique was observed. The defects were smaller (1.9 cm) than the original prominent tumors (3.6 cm). Defect size was dependent on the operative technique: closure by suture of the renal capsule in smaller defects or by fat flap in larger ones. Postoperative hematomas or delayed perfusion in the adjacent parenchyma were seen in five patients. Tumor recurrence was correctly diagnosed in one patient.

Carcinoma, Renal Cell↗

PubMedDate not supplied

[Congenitally corrected transposition of the great vessels throughout ventricular inversion (author's transl)].

Congenitally corrected transposition of the great vessels is a cardiac anomaly in which the pulmonary artery and the aorta are transposed in relation to one another but in which the flow of blood is maintained in the physiologic direction. In this condition there is a concomitant inversion of the ventricular chambers. 8 patients--5 adults and 3 children--with this condition have been reviewed with special attention to clinical symptoms and electrocardiographic and roent-genologic features. The anomaly is of importance because it is much more common than formerly believed. Frequently associated cardiac defects are correctable by surgical procedures. Therefore a preoperatively firmly established disgnosis is necessary by angiocardiography and heart catheterization.

Adolescent↗

PubMedDate not supplied

Percutaneous penile venoablation for treatment of impotence.

Percutaneous penile venoablation with sclerosing agents and coils was performed in 58 patients. Of 104 ablations attempted, 44 of 51 (86%) transpenile, and 46 of 53 (86.7%) retrograde interventions were technically successful. In 40 patients (69%) erectile function improved (intercourse was possible in 21 without additional measures). Initially improved erectile function deteriorated in 24 patients during follow-up (in an average of 6 months); in 15 of these, intercourse was still possible with injection of vasoactive drugs. In 7 patients, repeat venoablation improved erectile function again. Hot contrast medium was slightly superior to sodium morrhuate as a sclerosing agent. In successfully treated patients, the average decrease in venous leakage was 30 ml/min vs 13 ml/min in treatment failures, with considerable overlap between both groups. Only minor complications were observed. We conclude that percutaneous penile venoablation is technically feasible, and safe. Whether the procedure will have a definite role in the treatment of venogenic impotence, however, still has to be determined.

Embolization, Therapeutic↗

PubMedDate not supplied

Molecular properties of reconstituted cytochrome c oxidase: new evidence supports vectorial proton translocation.

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Animals↗

PubMedDate not supplied

Tissue characterization of benign brain tumors: use of NMR-tissue parameters.

To evaluate the potentials of NMR tissue parameters for tissue characterization we investigated 68 patients with benign brain tumors. Tissue parameters were accurately measured by a recently developed interlaced triple sequence. Each individual tumor was characterized by a set of three numbers (relaxation times T1 and T2 and proton density Rho). Different tumors exhibited significant overlaps of the three tissue parameters. Therefore a reliable prediction of the histological diagnosis based on the quantitative analysis of tissue parameters alone was not possible. T2-prolongation correlated well with water content and "regressive changes" in meningiomas and neuromas.

Adenoma↗

PubMedDate not supplied

Transrenal ureteral occlusion: results and problems.

PURPOSE: The effectiveness of transrenal ureteral occlusion was evaluated. PATIENTS AND METHODS: Transrenal ureteral occlusions were performed in 83 ureters of 76 patients. Thirty-one ureters were occluded with use of tissue adhesive, which was secured in place with Gianturco coils in 21. Fifty-two ureters were occluded by means of silicone-filled, detachable latex balloons. Average follow-up was 3.6 months (range, 1 week to 38 months) for patients treated with the tissue adhesive and 7.9 months (range, 1 week to 61 months) for patients treated with the detachable balloons. RESULTS: Seventeen (55%) of the 31 ureters occluded with tissue adhesive and 36 (69%) of the 52 ureters occluded with detachable balloons were permanently sealed after a single procedure. In 30 ureters, the occlusion procedure had to be repeated. The average duration of temporarily effective occlusions was 2.5 weeks when tissue adhesive was used and 19.5 weeks with detachable balloons. Complications were observed in 10 (7%) of 138 interventions. Only four of these were considered significant: two perforations occurred at the ureteropelvic junction, septicemia was seen after one procedure, and damage to a small intrarenal artery necessitated selective embolization in one patient. CONCLUSIONS: In selected patients, transrenal ureteral occlusion can effectively and safely interrupt urinary flow toward the bladder. Detachable balloons were superior to tissue adhesive as an occluding agent.

Aged↗

PubMedDate not supplied

Spiral CT of bronchial arteries in chronic thromboembolism.

OBJECTIVE: Computed tomography study of bronchial artery anatomy and evaluation of dilatation and tortuousity as indicators for pulmonary hypertension and surgical risk in patients with chronic thromboembolism were performed. MATERIALS AND METHODS: We retrospectively reviewed contrast-enhanced, thin section spiral CT scans of 39 patients undergoing pulmonary thromboendarterectomy. Findings were compared with mean pulmonary artery (PA) pressure in all, postoperative mortality in 33, and postoperative CT in 5 patients. Twenty patients without pulmonary hypertension served as controls. RESULTS: In the pulmonary hypertension group, 50 bronchial arteries were observed in 30 of 39 patients. Their prevalence was significantly higher than in the control group (p < 0.0001). Their proximal diameter measured > or = 1.5 mm in 20 patients (51%); a tortuous course was found in 14 (36%). The correlation between total bronchial artery diameter and mean PA pressure was poor (r = 0.2). Patients with dilated bronchial arteries had a significantly lower risk for postoperative death than patients without (p < 0.05); positive predictive value was 100% and confidence interval 0.79-1.0. Despite normal postoperative PA pressures, bronchial arteries were still visible on follow-up studies. CONCLUSION: The CT depiction of bronchial arteries, dilatation, and tortuousity provides indicators for chronic thromboembolic pulmonary hypertension. Its degree cannot be estimated. Dilated bronchial arteries are a significant predictor for survival of pulmonary thromboendarterectomy.

Adolescent↗

PubMedDate not supplied

Angiogenesis and fibroblast proliferation precede formation of recurrent tumors after radiation therapy in nude mice.

Recently, the combination of ionizing radiation with inhibitors of angiogenesis has been reported to improve tumor eradication compared to treatment with irradiation alone. However, the mechanisms of this effect have not been defined. For this purpose [corrected] we established a non-small cell lung cancer model in nude mice. Tumor vascularization was visualized in vivo by MRI using gadolinium-DTPA as contrast agent. Further, cryosections were produced as close as possible to the MRI slice positions. Since we were interested in examining the formation of a recurrent tumor, irradiation was performed with a single fraction of 4 Gy. This dose caused a partial remission followed by recurrent tumor growth 25 to 35 days after therapy. The process of partial remission as well as formation of the recurrent tumor was examined in 28 nude mice analysing the following parameters: (i) contrast agent enhancement using high-resolution MRI, (ii) proliferation of tumor cells and fibroblasts using Ki-67 immunohistochemistry and (iii) formation of microvessels using CD31 immunohistochemistry. The latter analyses led to differentiation of three stages. Stage 1 (day 1 to day 15 after irradiation) was characterized by increasing areas of dead cell mass in hematoxylin-eosin-stained slides that corresponded to a decrease in tumor cell proliferation as well as contrast agent enhancement in MRI. The percentage of Ki-67-positive tumor cells decreased from initially 45.1% +/- 6.0% (mean +/- standard deviation) to 1.4% +/- 1.2% (mean +/- standard deviation) on day 15. Stage 2 (day 6 to day 20 after irradiation; overlapping with stage 1) was characterized by proliferation of fibroblasts leading to formation of fibrotic septae with abundant microvessels. Already during late stage 2, MRI identified new contrast agent enhancing areas. Stage 3 (day 20 to day 40 after irradiation) was characterized by new tumor cell proliferation. Interestingly, tumor cells almost exclusively proliferated in the direct neighbourhood of the fibrotic septae that had been formed in stage 2. Obviously, proliferation of fibroblasts and blood vessels was a condition prior to formation of recurrent tumor tissue. Thus, our results are in contrast with the view that tumors or recurrent tumors begin as avascular masses that later induce neovascularization. With respect to clinical practice, our results suggest that: (i) adjuvant anti-angiogenic therapy should not be limited to the day of irradiation but should cover a critical period until day 5 to day 20 after radiotherapy, (ii) adjuvant therapy should also include inhibition of fibroblast proliferation and (iii) MRI can identify a recurrent tumor 10 to 15 days before occurrence of new tumor growth.

Animals↗

PubMedDate not supplied

MR imaging in Aicardi syndrome.

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Agenesis of Corpus Callosum↗

PubMedDate not supplied

[Abnormalities of the brain in childhood in nuclear magnetic tomography].

25 of about 300 infants and children, who had been examined by magnetic resonance imaging since 1984, had a congenital malformation of the brain. Cystic malformations (e.g. arachnoid cysts) were the most frequent lesion. Other findings were: Arnold-Chiari malformation, septo-optic dysplasia, Dandy-Walker syndrome, agenesis of the corpus callosum, migration disorders. The multiplanar slice orientation and the good tissue contrast in magnetic resonance imaging supplied a clear diagnosis in all cases. Compared with other imaging modalities (CT, ultrasonography) the depiction of the morphology was superior in MR imaging in most cases.

Agenesis of Corpus Callosum↗