Calculated T1 and T2 MR images and 31P MR spectra in rabbit thigh V2 carcinoma to monitor the effect of steroid administration.

T1 and T2 proton relaxation times in six rabbit thigh V2 carcinomas were obtained from regions of interest on calculated MR images at 2.35 tesla before and after steroid administration. Mean T1 and T2 values of viable tumor tissue decreased after steroid administration, consistent with decreased tissue water content. After steroid withdrawal, T1 and T2 values returned toward baseline. Relaxation times of peritumoral muscle tissue and normal contralateral thigh muscle essentially remained unchanged. In a separate experiment, six rabbit thigh V2 carcinomas were monitored before and after steroids by 31P spectroscopy using a surface coil. No substantial steroid-related changes were recognizable. A fall of the ratio of phosphocreatine to inorganic phosphate and a signal increase from phosphomonoester and phosphodiester compounds were observed during various stages of tumor growth. Analysis of 31P spectra changes and sequential measurements of relaxation times may prove valuable for assessment of tumor growth and therapeutic response in diagnostic oncology.

Variability of cardiomyocyte DNA content, ploidy level and nuclear number in mammalian hearts.

DNA content, ploidy level, cell size and nuclear number were investigated in 54 mammalian hearts from nine species. DNA content was determined biochemically and ploidy level of cells was studied by the means of Feulgen cytophotometry. Nuclear number was calculated by a new method, while cell size was determined by using ocular micrometry. In most mammals diploid cell nuclei predominate. Higher ploidy levels were found in the human and the pig hearts. The total amount of DNA correlated with the myocardial weight. Eight million heart muscle cell nuclei were found in mice (myocardial weight 160 mg), and 2600 million heart muscle cell nuclei in the human heart (myocardial weight 210 g), but in the hearts of horses up to 35000 million heart muscle cell nuclei (myocardial weight 3.4 kg) were found. The number of heart muscle and connective tissue cell nuclei was correlated with myocardial weight. The ratio of connective tissue cell nuclei to heart muscle cell nuclei was between 2:1 and 3:1. In cardiac growth this ratio shifted towards connective tissue cell nuclei. Increased heart weight corresponds to an increase in cell size. Diameter between 11 microns and 18 microns may be an optimum for heart muscle cells of mammals.

Hemangioblastomas of the central nervous system. A 10-year study with special reference to von Hippel-Lindau syndrome.

The findings of a 10-year study (1976 to 1986) conducted in southwest Germany on hemangioblastomas (HBL's) of the central nervous system (CNS) are presented. During that period, 47 HBL's were diagnosed and surgically removed in 44 patients, with a good postoperative survival rate and prognosis. The majority (83%) of these tumors were located in the cerebellum. By thorough clinical examination of the patients and careful evaluation of their family background, it was found that 23% of the HBL patients were afflicted with von Hippel-Lindau syndrome. In addition to the CNS tumors, 14 neoplastic or similar lesions were detected in other tissues. These included angiomatosis of the retinae, pheochromocytomas, pancreatic cysts, renal cysts, and renal carcinoma. The diagnosis of von Hippel-Lindau syndrome was thus established in seven families. The authors suggest the need for a screening program for patients with HBL of the CNS which is designed to confirm or exclude ocular or visceral lesions associated with von Hippel-Lindau syndrome.

Clinical applications and methodological developments of the RARE technique.

The RARE technique is an extremely useful tool for clinical diagnosis, since it delivers images comparable to those produced by X-ray myelography and X-ray urography. Contrary to these methods, RARE does not use the application of contrast agents. A low-flip-angle variant called FLARE (fast low angle refocused echo imaging) makes this technique accessible for high-field systems.

Fast and exact flow measurements with the fast Fourier flow technique.

The fast Fourier flow technique offers a convenient way for extremely exact flow measurements. In combination with ECG gating, arterial flow can be studied. The total acquisition time for a single measurement is about 10 s, an ECG-gated cine sequence can be acquired in about 4 min. Fast Fourier flow can, therefore, be easily combined with a conventional imaging examination.

Measurement of CSF flow using an interferrographic MR technique based on the rare-fast imaging sequence.

A fast MR sequence based on the RARE-myelographic technique allows the determination of cerebrospinal fluid (CSF) flow with a flow sensitivity below 1 mm/sec. The method averages flow over the ECG cycle and consequently measures net flow rather than ECG-dependent flow variations. The noninvasivity of this technique and the very short acquisition time of about 5 sec make this sequence a very useful diagnostic tool for a variety of CSF-flow dependent disorders like the determination of different types of hydrocephalus, the control of shunt operations and the assessment of communication pathways between CSF and cysts.

Morphologic development of human shock lung.

In the initial phase of shock, edema spreads throughout the alveolar interstitium even before injury occurs in the alveolar epithelium and endothelium. The endothelium and the epithelium are damaged only subsequently, causing reduction in the average barrier thickness of the epithelium and the endothelium. A point of irreversibility is reached by the end of the first week. While early cell regeneration may be observed within the alveolar endothelium and epithelium, proliferation of fibroblasts and fibrosis of the alveolar wall occur in addition to edema which spreads within the interstitium. This widening of the gas exchange barrier may be considered as the anatomic substrate of respiratory insufficiency induced by shock. This enlargement continues up to the moment when thickening of the alveoli impedes satisfactory functioning of the lung, and, as consequence, threatens the life of the patient.

[RARE-MR myelography in routine clinical practice. Experience with 175 cases]. / RARE-MR-Myelographie in der klinischen Routine. Erfahrung mit 175 Fällen.

In 1984 Henning, Nauerth, Friedburg and Ratzel described a new MRI data acquisition technique called RARE (Rapid Acquisition with Relaxation Enhancement). Several clinical applications have been published. A modification developed in the meantime, called "RARE hydrography", yields T2-weighted aqueous fluid specific images within a few seconds. As a nontomographic rapid approach to MR-myelography ("RARE-myelography") this technique is routinely applied at the beginning of all examinations of the spine. On the basis of 175 cases current potentials and limitations are discussed. Future applications of 3D-RARE myelography are mentioned.

[Pathology of the craniocervical junction as shown by magnetic resonance tomography. 68 cases]. / Pathologie des kraniozervikalen Ubergangs in der magnetischen Resonanztomographie. 68 Fälle.

In cases of a suspected lesion at the level of the cranio-cervical junction, MR should be considered as the imaging technique of choice. Tumours, inflammation and degenerative processes can be reliably demonstrated and diagnosed. Administration of contrast media, for example, gadolinium-DTPA, is necessary in selected cases only. Comparing "examination time" of x-ray myelography and high resolution x-ray CT with MR, one can well tolerate the long "acquisition" of MR images.

[Angiographic problems in angiomyolipoma of the kidney report on 3 cases (author's transl)]. / Angiograhische Probleme beim Angiomyolipom (AML) der Niere. Bericht über drei eigene Beobacntungen.

3 cases of unilateral angiomyolipoma of the kidney are presented. Angiography was unsuccessful in diagnosing angiomyolipoma in these cases observed by us. The diagnostic problems of the angiomyolipoma are discussed on the basis of histologic and angiographic findings. No patient showed simultaneously tuberous sclerosis.

[Thin-layer NMR-imaging with a new T2-weighted 3-D-procedure]. / Dünnschicht-NMR-Imaging mit einem neuen T2-gewichteten 3-D-Verfahren.

Presentation of first experience with a new 3-dimensional data acquisition method. The new method yields sets of 120 continuous images of the head and brain in all 3 dimensions (slice thickness and spatial resolution both being 1.7 mm.) with a data acquisition time of 15 minutes. Depending on pulse sequences T1- or T2-images are available. Advantages and disadvantages are discussed.

[Traction injuries of the brachial plexus: radiologic diagnosis using myelo-CT and MR]. / Traktionsverletzungen des Plexus brachialis: radiologische Diagnostik mit Myelo-CT und MR.

The exact radiographic localisation of supraganglionic lesions of the brachial plexus provides important information for the prognosis and clinical management of these injuries. The authors report on the results of enhanced CT scanning and MRI of the cervical spine in five patients with surgically proven root avulsions caused by traction injuries. All lesions were correctly diagnosed by enhanced CT scanning. MRI, by comparison, identified only about 70% of the neural lesions.

[Malignant fibrous histiocytoma of soft tissue. Pathology and radiology of an unusual sarcoma]. / Malignes fibröses histiozytom der Weichteile. Pathologie und Radiologic eines eigenartigen Sarkoms.

Four cases of malignant fibrous histiocytomas are reported. An attempt is made to determine some characteristic roentgenologic features of this disease. There is no pathognomonic radiologic sign; however, angiographic documentation of hypervascularization together with neovascularity and absorption values of about 35 HE in computed tomography suggest a predominantly fibrous sarcoma. Differential diagnosis on abscess formation, tumours of the fat tissue and primary vascular neoplasms should be performed and these conditions ruled out if not applicable.

[MR of the urinary tract in pregnancy]. / MR der Harnwege in der Schwangerschaft.

A report on the application of standard 2D-FT MR combined with RARE-MR-Urography in a pregnant woman with right sided abdominal pain, dilated upper urinary tract and possible stone or inflammatory disease. This technique visualised the complete obstructed ureter in relation to the surrounding organs (uterus, vessels), allows precise diagnosis of the cause of the obstruction and avoids ionising radiation.

[Monitoring studies of survivors of shock lung (ARDS). Correlation of radiology and lung function]. / Verlaufsbeobachtungen bei überlebter Schocklunge (ARDS). Korrelation von Radiologie und Lungenfunktion.

21 patients, who survived acute respiratory insufficiency following shock, are examined for residual pulmonary lesions. Retrospectively various parameters (f.e. blood gaz, radiological alterations) are analysed and correlated with results of a follow-up study (pulmonary function, chest films). Significant impairment of pulmonary functions could not be documented in a single patient. Roentgenologic late sequelae are seen only in two patients, which had a minor impairment of pulmonary function.

Inflammatory and traumatic lesions of the knee and ankle: comparison of 0.23 T and 2 T MRI.

Fifty-six patients with traumatic and 117 patients with inflammatory lesions of the knee and ankle were examined with a 2 T (69 examinations) or 0.23 T (104 examinations) MR system. The quality of all images was assessed by the consensus of three radiologists on a scale of diagnostic (3+, 2+) and nondiagnostic (1+) image quality. More than 90% of images from both systems were diagnostic. However, the proportion of 3+ quality images was significantly higher (p less than 0.001) at the magnetic field strength of 2 T (81% = 56/69 versus 49% = 51/104 at 0.23 T). Motion artifacts were the main cause of reduced image quality independent of field strength. In patients with traumatic and inflammatory diseases of the knee and ankle, high field imaging at 2 T provided better image quality than low field imaging at 0.23 T.

[Initial clinical experiences with RARE-MR urography]. / Erste klinische Erfahrungen mit der RARE-MR-Urographie.

Potentials and limitations of a new, facultative non-tomographic Fast-Imaging sequence "RARE-MR-Urography" are presented. Its results in urological diseases are discussed on the basis of a pilot study of 35 patients. The images (4 s-32 s acquisition time) are extremely T2-weighted and display unbounded free water (urine). They reveal valuable information, not available with ultrasound or conventional radiology without application of contrast agents in the presence of urine retention. S/N problems reduce the accuracy of this method if the urinary tract contains only small amounts of urine.

[Clinical benefit of compensation of motion artefacts in contrast media enhanced MRI mammography]. / Klinischer Nutzen der Kompensation von Bewegungsartefakten in der kontrastmittelgestützten MRT-Mammographie.

This article discusses the diagnostic benefit of methods for the compensation of motion artefacts in dynamic MRT-Mammography with a contrast agent. Our algorithms for motion compensation perform a locally rigid registration of cubic sub-volumes and a locally affine deformation of tetrahedral sub-volumes from a Delaunay-Triangulation. Within an extensive clinical study, these fast, automatic, and robust algorithms have been applied to 64 MRT-Mammography datasets from the radiological practice of Dr. Friedburg. The comparison of corrected datasets with original data and the statistical evaluation of results show a significantly improved quality of difference images, particularly at the presence of large motion artefacts.