[The present status of the radiologic diagnosis of acute pulmonary failure]

Acute pulmonary failure is a very serious cause of respiratory failure and can occur in association with a multitude of disease. Radiological diagnosis occupies a central position in intensive-care monitoring. X-ray film of the thorax is performed not only for detecting any complications, but mainly for noninvasive and semiquantitative determination of the extravascular pulmonary fluid and hence of the fluid balance, although it is imperative to take into account any influence that associated disease and therapy measures. Other methods such as MR or methods of nuclear medicine have not acquired substantial importance in respect of diagnosing and monitoring acute pulmonary failure.

[Magnetic resonance tomography studies with contrast media in post-discotomy syndrome]

The syndrome encompassing failed back-surgery is a relatively uniform combination of complaints caused by a variety of pathological changes in the lumbar spine, alone or in various combinations. The MRI's capability of detecting these factors is described. MRI can detect recurrent disc herniations and separate them from intradural and/or extradural scar formation. With further experience, MRI might also be able to assess instability of the lumbar spine motion segments. MRI is not very helpful in detecting neural lesions or facette syndromes. For this kind of pathology, advances in diagnosis will depend on the further improvement of neuro- and electrophysiological tests. The same applies to the diagnosis of cases of spinal stenosis. The size of the spinal canal can be measured by MRI as well as by other modalities. These results just point out the risk of disease - not the disease itself.

Angiomyolipoma of the kidney. Comparison between magnetic resonance imaging, computed tomography, and ultrasonography for diagnosis

In six patients with angiomyolipoma of the kidney, five showed a typical pattern in T1, proton and T2 weighted images, with magnetic resonance imaging (MRI). Angiomyolipoma is recognized by its characteristic fatty tissue components, which result in high signal intensity in T1 and proton weighted images and a low signal in T2 weighted images. Five of the patients were also examined with ultrasonography (US); in four of these, the tumor could be recognized by its echodense pattern. Computed tomography (CT) was slightly less sensitive; three out of six examinations failed to produce a definite diagnosis. Instead of the typical low attenuation values of fat, Hounsfield units similar to either muscle or kidney tissue were observed in these 3 cases. In conclusion, the specific diagnosis of angiomyolipoma depends on the amount of fatty tissue present at MRI, CT, and sonography.

[Follow-up of combined radiotherapy and chemotherapy of advanced bladder cancer using magnetic resonance tomography. Initial results]

A combination of cis-platinum and radiotherapy was applied in five patients with advanced bladder carcinomas. The patients were examined by nuclear magnetic resonance imaging prior to and following therapy. Corresponding to cell-kinetic considerations regarding tissues with slow cell turnover, a maximum therapy effect is shown about nine months after the end of local therapy. Smaller control intervals are recommended in case of bladder carcinomas with lymph node metastases. Due to the possibility of multiple slice imaging, the nuclear magnetic resonance technique is particularly suited for the monitoring of bladder carcinomas. Sagittal and coronary slices show a better image of tumoral extension at the roof and floor of the bladder than axial computed tomography. Lymph node metastases are represented relatively late by both methods.

[31-P-spectroscopy as a method for studying biochemical changes in skin tumors: exemplified by malignant melanoma and squamous cell carcinoma]

We report on the basic principles concerning in vivo P-31 MR spectroscopy and give a short review of the corresponding studies on skin tumors described in the literature. Malignant melanoma and squamous cell carcinoma are both characterized by high concentrations of phosphomonoester and phosphodiester. By means of the P-31 spectroscopy technique, we are able to detect changes regarding the tumor metabolism as a response to chemotherapy, irradiation, or biological immune modifiers (e.g. interferon).

[Importance of contrast medium administration in determining the age of traumatic renal hemorrhage by NMR tomography--experimental results]

In eleven Han-Wistar rats, experimental renal haematomas were produced and scanned by magnetic resonance tomography at two hours to 21 days. Bleeding during the first three or four days showed prolongation of T1 and T2 relaxation times. On subsequent days there was shortening of the T1 and T2 times. Gadolinium DTPA produced a marked effect in the second to fourth day following the trauma, if the examination was carried out 90 to 120 minutes after the administration of contrast medium. Gadolinium can be used in determining the age and clarifying the differential diagnosis of an bleeding if there is clinical support.

[Spin-echo sequences and rapid image sequences in a comparison of spinal diseases]

Rapid image sequences of the spine were compared with proton and T2-weighted spin-echo sequences in 30 patients concerning their diagnostic value and image contrast. The rapid series was carried out with an angle of rotation of 30%, TR of 21 and TE of 12 msec., the spin-echo sequences with a TR/TE of 2,000/20/80 msec. The quality and contrast of the rapid series was markedly inferior to the spin-echo sequences; this was particularly marked for demonstrating disc and bone degeneration. At present, the routine use of rapid sequences cannot be recommended as a substitute for spine-echo examinations.

MR imaging in multiple sclerosis: comparison with clinical, CSF, and visual evoked potential findings

MR examinations of 136 patients with multiple sclerosis (MS) were evaluated to correlate the results with clinical, CSF, and visual evoked potential (VEP) findings. In addition, 22 of the 136 patients were studied several times during a 5-month follow-up period. It was demonstrated that MR is superior to CSF and VEP findings in establishing cerebral alterations in MS. A relationship between the results of CSF and VEP examinations and the MR results could not be detected. Negative CSF and VEP results corresponded to positive MR imaging and vice versa. In our series, five negative MR results were obtained in patients with clinically proved MS. The extent of alterations shown up by MR corresponds to the duration of the disease; in particular, more confluent abnormalities in the periventricular region were found in patients with long-standing disease. More plaques were found in patients with a primary relapsing/remitting course of the disease than with the primary chronic progressive form. The clinical course and the grade of disability did not correspond to differences in MR imaging. Follow-up demonstrated that most lesions remain unchanged (72-79%); increases and decreases in the size of the plaques seem to depend on the clinical course. These results suggest that MR is the most sensitive technique for establishing the diagnosis of MS.

Magnetic resonance imaging in evaluating focal liver lesions

We report the results of magnetic resonance imaging (MRI) of the liver in 46 patients with various previously confirmed focal lesions. A characteristic signal pattern was found in hemangiomas (n = 11), with marked signal hyperintensity on T2 and proton weighted images as compared to normal liver tissue. Cysts (n = 7) also showed marked hyperintensity on T2 images, but could easily be differentiated by a lesser intensity on proton weighted images and signal hypointensity on T1 weighted images. Primary liver tumors (n = 4), metastatic liver disease (n = 18), focal nodular hyperplasia (n = 5), and liver adenoma (n = 1) revealed a weak signal hyperintensity on T2 images, with varying signals in T1 and proton weighted modalities. These data combined with other recent communications in the literature indicate that MRI is a promising diagnostic technique in the detection of focal liver lesions and that it may offer a high degree of specificity in the diagnosis of hepatic hemangiomas and benign cysts.

[NMR tomographic studies in experimental renal vein ligation]

Experimental ligation of the renal veins in rats indicate highly significant and characteristic changes within two hours, consisting of significant prolongation of T2 relaxation time in the cortex and T2 shortening in the medulla. In addition, there is a considerable increase in the size of the kidney, due to swelling of the cortex. T2 prolongation of the cortex is most marked between 30 hours and two to four days after ligation of the vein. In the following weeks there is a return to normal. T2 of the medulla at two to three weeks after ligation shows highly significant reduction compared with the normal side and, at this time, the size of the experimental kidney is significantly less than the opposite kidney. These results indicate that magnetic resonance tomography is a highly sensitive method for the early demonstration of renal vein thrombosis.

[Nuclear spin tomography and computerized tomography in malignant hypernephroma]

Forty patients with histologically confirmed hypernephromas were examined by MR and CT. As regards T-staging, MR had an accuracy of 97% and CT of 91%; for N-staging, MR had an accuracy of 85% and CT of 91% and, with regard to infiltration of the renal vein, MR was correct in 88% of cases and CT in 81%. MR was most accurate in the pre-operative assessment of tumour spread, demonstrating caval involvement in 100% and lymph node metastases in 97%. On the other hand, infiltration of the renal pelvis could be assessed in only 65% of cases; in 27% the assessment was not possible and in 8% one could not be certain. CT proved to be at its best for staging of lymph nodes, but in 15% it was not possible to identify infiltration of the renal vein. MR was not greatly superior to CT in the preoperative diagnosis and staging of hypernephromas.

[Significance of nuclear magnetic tomography in the diagnosis of lumbar disk displacements]

In a prospective study we determined the validity of MRI (Magnetic Resonance Imaging) in lumbar disc herniations. MRI and CT were compared in 34 patients who underwent operation and 8 patients who underwent discography and intradiscal injection. By this study we determined the validity of CT and MRI being more than 90%.