[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.

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.

Pancreatic lesions in the von Hippel-Lindau syndrome.

Common manifestations of the von Hippel-Lindau syndrome, an autosomally dominant inherited cancer-prone disorder, include retinal angiomatosis, hemangioblastoma of the central nervous system, renal cysts, renal cancer, pheochromocytoma, and epididymal cystadenoma. Multiple cysts and microcystic (serous) cystadenomas of the pancreas have also been reported occasionally in patients afflicted with this syndrome. In the large Freiburg study of the von Hippel-Lindau syndrome composed of 66 affected individuals, pancreatic lesions were systematically studied. Fifty-five living individuals were examined by abdominal ultrasound imaging. Abnormal findings were confirmed by computed tomographic scan and/or magnetic resonance imaging. For an additional 11 decreased patients autopsy data were available. Cystic lesions of the pancreas were found in 10 patients (15%). One of these patients presented with multiple pancreatic cysts as the only manifestation of the syndrome. In one patient, a malignant islet-cell tumor was found at autopsy. Because multiple pancreatic cysts did not cause major clinical symptoms and because follow-up examinations over an average period of 5 years did not show significant progression of the lesions, it is concluded that these patients usually do not require surgical treatment. Abdominal ultrasound screening is recommended for patients at risk as a tool to identify potential von Hippel-Lindau syndrome gene carriers with pancreatic manifestations. In all patients with multiple pancreatic cysts, the von Hippel-Lindau syndrome should be included in the differential diagnosis.

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.

[Attempt at staging articular changes in rheumatoid arthritis using magnetic resonance tomography exemplified by the wrist joint]. / Versuch der Stadieneinteilung artikulärer Veränderungen bei der rheumatoiden Arthritis mittels Magnetresonanz-Tomographie am Beispiel des Handgelenkes.

Sixty-four examinations of the wrist in patients with rheumatoid arthritis by magnetic resonance imaging using a 0.23 TESLA magnet showed a great sensitivity in detecting proliferative partly exudative or destructive synovialitis, as is common in rheumatoid arthritis. In accordance to the Larsen system for grading rheumatoid arthritis lesions by conventional x-ray, we establish a clinically relevant magnetic resonance grading system which is able to diversify the stages of destruction and inflammative activity in rheumatoid arthritis.

Side-effects of extracorporeal piezoelectric shock wave lithotripsy (EPL).

In the Department of Urology, University of Freiburg, West Germany extracorporeal piezoelectric shock wave lithotripsy (EPL) has been used in the treatment of urinary and biliary stones since November 1987. The first 85 treatments (in 71 patients) for renal stones were evaluated with regard to complications and side effects. There was no need for any anesthesia. Urinary obstruction was observed in 12% of the cases. Aside from the urinary obstruction and urosepsis (2%) no serious complications were seen. Endourological auxiliary measures were applied in 32% (27% prophylactically). The temporary glomerular damage which appeared in some patients vanished within 6 days after treatment. Because of possible asymptomatic ureteral obstruction a close follow up by ultrasound is recommended. EPL was found to be a useful method of treatment for renal calculi with few side effects.

Rheumatoid arthritis lesions of the wrist examined by rapid gradient-echo magnetic resonance imaging.

Alterations of magnetic resonance imaging (MRI) relaxation time and intensity can be helpful in the diagnosis of rheumatoid arthritis (RA) lesions like synovial infiltration, local inflammation and exudation. Fast low angle shot magnetic resonance imaging (FLASH-MRI) is a rapid method showing anatomy and inflammatory pathology of the examined joint comparable to late spin echo T2 images. The following study presents our results of FLASH-MRI wrist examinations of 15 patients suffering from RA according the ARA criteria and 10 healthy volunteers compared to T1 and T2 weighted MR-images and conventional X-rays.

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.

[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.

The importance of the voxel size in clinical 1H spectroscopy of the human brain.

It is demonstrated that it is possible to acquire two volume selective 1H NMR spectra of human brain in vivo, consisting of voxels of 1.5 X 1.5 X 1.5 cm3, within 14 min with a good S/N ratio. This is mainly achieved by the application of a PRESS sequence generating a spin-echo of the VOI at 135 ms in conjunction with the STABLE technique by which two spectra can be recorded in an interlaced mode. The Bo homogeneity over such small voxels is considerably higher than over larger voxels. With these methodological improvements it is possible to observe morphological heterogeneity of tumors. The results indicate that spectral changes seem to correlate with the metabolic state of the tumor rather than the tumor type. Additionally the spectrum of a patient with multiple sclerosis suggests that even differentiation between tumors and other lesions might not be possible.

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.

[The Cruveilhier-von Baumgarten syndrome. Presentation of radiologic findings based on a case]. / Das Cruveilhier-von-Baumgarten-Syndrom. Demonstration der radiologischen Befunde anhand eines Fallbeispiels.

Marked portosystemic venous anastomosis of the parumbilical veins is referred to as the Cruveilhier-Baumgarten syndrome. Opening of these vessels has been described mainly in the sonographic literature. In this case report CT and MR findings are presented, which have been confirmed by angiography. This paper is intended to draw the radiologist's attention to dilatation of the parumbilical veins, which is a highly specific sign of portal hypertension resulting from intrahepatic blockage.

[Predictive value of magnetic resonance tomography in comparison with sonography and computed tomography in the diagnosis of focal liver lesions]. / Aussagekraft der Kernspintomographie im Vergleich zu Sonographie und Computertomographie in der Diagnostik fokaler Leberläsionen.

Ultrasonography and computed tomography are widely used for the diagnosis of focal lesions of the liver. However, the possibilities for tumor characterization and determination of potential malignancy are limited in many cases. Evaluation by magnetic resonance imaging shows a good correlation of relaxation time with the amount of stroma as a proportion of the total cell content of a lesion. This allows differentiation for a number of lesions. Thus, the combination of ultrasonography and magnetic resonance imaging could provide the ideal diagnostic procedure in many cases.

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.

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.

Quantitative flow measurement with the fast Fourier flow technique.

The fast Fourier flow method of magnetic resonance (MR) imaging offers a fast and efficient way of measuring quantitative flow for velocities within the range from several millimeters per second to more than 1 m/sec. When fast Fourier flow imaging is used in combination with echocardiographic gating, arterial flow can be determined and velocity versus time profiles can be generated. Because of the high spatial resolution, down to 0.3 mm, detailed examination of flow profiles is possible even in smaller vessels. The method works equally well on a low-field-strength system operating at 0.23 T and on a high-field-strength system with 4.7-T field strength. Since the experiment is very fast, with acquisition times ranging from 4 seconds for a single-section experiment to about 4 minutes for the electrocardiographically gated variant, it can easily be combined with a conventional MR imaging examination.