[Multiplanar angulated 2D reconstruction. A new CT technique for imaging the facial nerve canal]. / Multiplanar angulierte 2D-Rekonstruktion. Eine neue CT-Technik zur Darstellung des Fazialiskanals.

For imaging the facial canal in its tympanic and mastoid segments, a new technique was developed with high-resolution computed tomography (HRCT). This method is based on comparative anatomical studies and makes it possible to depict the course of the facial canal, especially in malformations of the middle ear and in cases of fractures, tumors and cholesteatomas. A longitudinal scan of the petrous part of the temporal bone is obtained by reconstruction based on primary axial CT-standards. In these longitudinal scans the facial canal is shown both in its tympanic and mastoidal segment. For longitudinal reconstruction the scan is orientated through the anterior margin of the carotid canal and petrous pyramid. For evaluating the facial canal in this study, the lateral semicircular canal and stylomastoid foramen are sure landmarks. The sensitivity for evaluating the tympanic segment of the facial canal is 100%. This new technique should be applied in cases in which the exact course of the facial canal must be known preoperatively.

Imaging of the facial canal by means of multiplanar angulated 2-D-high-resolution CT-reconstruction.

The facial canal containing the intratemporal portion of the facial nerve is very important for the otologist and radiologist concerning fractures and other lesions of the temporal bone. Axial and/or coronal standards are sufficient for imaging of the labyrinthine and the mastoidal segment of the facial canal. The sensitivity of visualization (sensitivity = number of identified structures per number of examinations) of the tympanic segment, however, is low and particularly the pyramidal segment (elbow, posterior knee) is not visualized in these standards. Based on anatomical considerations a new plain for imaging both the tympanic and mastoidal segment in continuity was obtained. The pyramido-longitudinal plain is achieved by a twice angulated 2-D-reconstruction based on axial high-resolution CT-scans.

Cervical cancer: serial MR imaging before and after primary radiation therapy--a 2-year follow-up study.

Serial magnetic resonance imaging studies were performed in 28 patients undergoing primary radiation therapy for invasive cervical cancer. T2-weighted spin-echo pulse sequences with long repetition times (2,500 msec) and echo times (30-100 msec) were used at a field strength of 1.5 T. Eighteen tumors responded promptly to radiation therapy with a volume reduction and significant decrease of signal intensity in the early posttreatment phase (1-3 months) and with total tumor regression at 1-6 months (immediate responders). At 6 months seven tumors were visible as residual tumors with declining signal intensity; all seven of these tumors had resolved at 9 months (delayed responders). Thus, a delayed response with residual tumor at 6 months was still compatible with subsequent clinical cure. The tumors showed progression and no marked change in signal intensity (nonresponders). Primary tumors with a volume of more than 50 cm3 were more likely to have no or delayed response. An early (2-3 months) and significant decrease in the signal intensity and volume of a tumor indicates a favorable response. Large primary tumors may show a delayed response.

MR-imaging with Gd-DTPA in carcinomas of tongue, oro- and hypopharynx.

High-field MRI was performed in a series of 24 patients with squamous cell carcinomas of the tongue, oro- and hypopharynx. The value of contrast enhanced T1-weighted images in tumor staging was established prospectively. Non-contrast T1-weighted images did not provide sufficient tumor-delineation. Marked contrast enhancement produced by Gd-DTPA was observed in all carcinomas and in normal pharyngeal mucosa. In tumors of the tongue and upper pharynx clinical examination and ultrasound were equally sensitive as post-contrast MRI; in tumors of the lower pharynx the true tumor extension could be better assessed by contrast-enhanced MRI.

[Value of magnetic resonance tomography after primary irradiation of carcinoma of the cervix uteri: evaluation of therapeutic success and follow-up]. / Stellenwert der Magnetresonanztomographie beim primär bestrahlten Karzinom der Cervix uteri: Therapieerfolgsbeurteilung und Nachsorge.

This study investigates the reliability of magnet resonance imaging in the evaluation of response to therapy and in follow-up after primary irradiation (RTX) of uterine cervical carcinomas in 25 patients (follow-up eleven to 39 months). Most of the tumors showed six months after RTX a significant reduction of volume and signal intensity in T2 weighted images. 20/25 (80%) showed a total tumor regression, 5/25 (20%) had a residual tumor (all of them had a primary tumor volume higher than 50 ccm). Four patients got a recurrent tumor in follow-up. Residual and recurrent tumors showed like the primary in heavily T2 weighted images significant higher signal intensity than fibrosis. Therefore posttreatment fibrosis is distinguishable from residual or recurrent neoplasm. Early radiation fibrosis (less than 6 months after RTX) showed higher signal intensity than fibrosis in later stages. This fact may be the cause of false positive results in searching for residual tumor within the first six months after RTX. Our results indicate that magnet resonance imaging is a reliable method to evaluate tumor response after radiation treatment and to detect recurrent neoplasm. The results of a greater patient population over a longer period of follow-up will be presented in future.

Obstructive jaundice: use of expandable metal endoprosthesis for biliary drainage. Work in progress.

Expandable metal endoprostheses were implanted transhepatically in 61 patients with obstructive jaundice. Fifty-three patients had malignant and eight had benign obstructions. Because of the small diameter of the compressed stent (7 F), primary implantation of the stent without a previous catheter drainage was preferred. Postprocedural complications occurred in three patients (5%) (biliary pleuritis, peritonitis, hepatic artery aneurysm). The 30-day mortality rate was 8.2%. Reocclusions were observed in six of the patients with malignant obstructions (11%) (observation period, 1-10 months; mean, 4.5 months) and in two of the patients with benign stenoses (25%) (observation period, 3-21 months; mean, 9 months). The higher reocclusion rate of benign obstructions must be interpreted with care because of the small number of patients. From their preliminary experience, the authors conclude that expandable metal endoprostheses offer patency rates equal to those of plastic stents. The implantation trauma is reduced due to the small 7-F introducing catheter system.

Diminished response to furosemide in I-123 Hippuran renal studies of renovascular hypertension caused by unilateral renal artery stenosis.

Dynamic I-123 Hippuran renal studies to measure furosemide response (FR) were performed in three groups of patients: 1) 57 patients with renovascular hypertension due to a poststenotic, ischemic kidney; 2) 23 patients with essential hypertension; and 3) 50 nonhypertensive patients with healthy kidneys (control group). FR was observed as renal parenchymal tracer washout within 10 minutes after the injection of 40 mg of furosemide. The retention index (RI) took into consideration the renal parenchymal tracer content before and 10 minutes after furosemide injection. In the control group, the FR was greater than 50% and the RI was less than 20. Patients with essential hypertension revealed no differences in the amounts of FR and RI compared with the control group. In renovascular hypertension, the FR was diminished and the RI was raised significantly. The values of FR and RI showed a good correlation to the degree of the renal artery stenosis before and after percutaneous transluminal angioplasty. It is concluded that the stimulation of diuresis with furosemide and its quantification represent an important additional step in the evaluation of dynamic I-123 Hippuran studies to detect renal ischemia.

[MR study of bone marrow changes of the spine following radiotherapy]. / MR-Untersuchung von Knochenmarksveränderungen in der Wirbelsäule nach Strahlentherapie.

MR examinations of bone marrow variations in the spine after radiotherapy were performed on 24 patients in the thoracic and lumbar vertebral column. The actinically affected bone marrow showed a characteristic increase of signal intensity in T1-weighted sequences in the sagittal plane, due to conversion of red marrow to fatty marrow. The dose in the well-defined radiation areas was between 28 and 70 Gray (Gy). The lowest dose, applied to the bone-marrow bordering on the defined radiation areas, where we still could find an increase of signal intensity, was below 2.6 to 5 Gy. MR imaging was performed between 6 and 9 month after radiotherapy.

Computed tomographic diagnosis of left superior vena cava and absence of the azygos vein: case report.

The radiologic findings on plain chest films and contrast-enhanced computed tomography (CCT) of the thorax in a case of isolated persistence of the left superior vena cava associated with absence of the right azygos vein are described. Chest x-rays allowed a presumptive diagnosis of the vascular anomaly. Confirmation of this anomaly was achieved by CT.

[Staging of cervix cancer using MRT]. / Staging des Kollumkarzinoms mit MRT.

In a prospective study the results of FIGO staging and MR staging in uterine cervical carcinoma were compared with the findings of stepwise serial examination of en-bloc-resected specimens in 28 patients. Overall accuracy of MR staging was 59% compared to 41% in FIGO staging. Sensitivity in assessing parametrial tumour extension was 85% in MRI and 64% in clinical examination. Specificity was 74% in MRI and 69% in physical examination. Accuracy in parametrial tumour extension was 67 per cent in FIGO-Classification and 80 per cent in MRI.

MR findings in methotrexate-induced CNS abnormalities.

MR of the brain was performed in eight patients (mean age, 14.9 years) with osteogenic sarcoma during or after IV treatment with high-dose methotrexate. MR detected brain abnormalities in four patients, three of whom had concomitant neurologic dysfunction. Pathologic findings demonstrated on MR were (1) chronic brain edema, demonstrable over a period of 3-14 months (proved by autopsy in one patient); (2) multifocal white matter necrosis; and (3) deep brain atrophy. MR appears to be valuable in the detection of abnormalities induced by treatment with high-dose methotrexate.

MR findings in methotrexate-induced CNS abnormalities.

MR of the brain was performed in eight patients (mean age, 14.9 years) with osteogenic sarcoma during or after IV treatment with high-dose methotrexate. MR detected brain abnormalities in four patients, three of whom had concomitant neurologic dysfunction. Pathologic findings demonstrated on MR were (1) chronic brain edema, demonstrable over a period of 3-14 months (proved by autopsy in one patient); (2) multifocal white matter necrosis; and (3) deep brain atrophy. MR appears to be valuable in the detection of abnormalities induced by treatment with high-dose methotrexate.

Magnetic resonance imaging in clinical cervical cancer: pretherapeutic tumour volumetry.

MRI can define the spread, size, and volume of clinical cervical cancers. Appropriate pulse sequences and slice thicknesses are necessary. Twenty-five patients underwent MRI tumour volumetry before radical hysterectomy. The volume obtained by MRI was compared with that obtained from the histological giant sections; the volumes agreed at a statistically significant correlation coefficient of 0.983. The volumes obtained by MRI of 13 unfixed surgical specimens correlated with their histological volumes with a statistically significant coefficient of 0.894. Tumour volumes were compared with the respective clinical stages. Clinical stage did not correlate with tumour volume. Three very large tumours were in clinical Stage Ib. Tumour size is a major prognostic factor, can be measured easily, and, as the basis for classification, is superior to FIGO staging. MRI can measure tumour volume before treatment.