PubMed Health⌕ Search

Biomedical subjects

C Frahm

Publications and source records attributed to C Frahm.

28 records · Page 2Linked to original sources
PubMed1996

[Technique of MRT-guided core biopsy in the abdomen using an open low-field scanner: feasibility and initial clinical results].

PURPOSE: Due to high soft-tissue contrast and multiplanar imaging capabilities MRI is an interesting modality to perform image-guided biopsies. We checked on the feasibility of MR-guided core biopsies of abdominal masses with an open low-field scanner (0.2 Tesla; vertical field axis). METHODS: 9 patients underwent MR-guided biopsies of abdominal target lesions (6 focal liver lesions, two adrenal masses, one pelvic mass). Different MR-compatible core biopsy instruments were used (needle diameters 14G-18G). MR scans during the procedures were obtained applying T1-weighted gradient echo sequences suitable for breath-hold imaging. RESULTS: In each case, needle guidance was reliable, so that the biopsy instrument could be positioned correctly. Multiplanar imaging capabilities enabled even angled approaches to upper abdominal masses to be realized safely. The combination of magnet design and table design offered suitable access to the patient. CONCLUSION: Using an open low-field scanner, MR-guided core biopsies of abdominal masses are practicable.

Abdomen↗
PubMed1996

[A technic of MRT-guided abdominal drainage with an open low-field magnet. Its feasibility and the initial results].

PURPOSE: To test the practicality of MRT-aided drainage using an open low-field magnet and to report on the early clinical results. METHODS: So far seven patients have been treated (four subphrenic abscesses, two psoas abscesses and one pancreatic pseudocyst). The planning of the approach and catheter insertion were carried out under MRT control (Magnetom Open, 0.2 T). Subsequent treatment was controlled by CT and fluoroscopy. Initial puncture was carried out with a non-magnetic 18 gauge Chiba needle. The drainage catheter was introduced by Seldinger's technique in six cases and with a trocar in one patient. RESULTS: In all seven patients drainage could be started successfully. The design of the magnet and coils permitted adequate accessibility of the patient. There were no problems in visualising the puncture needle. Controlling the position of the catheter by MRT was, however, difficult. CONCLUSION: The first two steps in abscess drainage (planning the approach and inserting the catheter) can be carried out under MRT control. For further catheter control and observing the course of the disease we presently prefer CT or fluoroscopy.

Abdomen↗
PubMed1996

[Anti-inflammatory and analgesic actions of of long-chain phenyl substituted alpha-aminoketones].

The investigated phenyl substituted alpha-amino ketones have anti-inflammatory and analgesic activities as could be shown in animal models (rats and mice). The effectiveness depends on the length of the alkyl chain. After i.p. application the most active amino ketones are ten times more effective than acetyl salicylic acid, but the activity did not reach that of indomethacin. The effective analgesic dose is ten times lower than that for anti-inflammatory action. Including the results of the toxicity the analgesic efficiency of the amino ketones could be lead to substances with high analgesic activity. After oral administration only in high doses anti-inflammatory and analgesic effectivities were found. The structural analog keto group instead of the ester or amid group leads not to the expected increase in p.o. effectivity.

Analgesics↗
PubMed1995

[The von Hippel-Lindau syndrome. Its differential diagnosis from cystic kidneys in adulthood].

A 51-year-old patient with severe back pain had undergone resection of a benign cerebellar tumour when aged 15 years. In addition, polycystic kidney disease was diagnosed 24 years ago, bilateral phaeochromocytoma 2 years ago, and for 4 months before the present admission he had been on haemodialysis. The family history indicated autosomal dominant inheritance of the polycystic renal disease. His general condition was found to have deteriorated, he had pain on pressure over the upper thoracic and lower lumbar vertebrae, and the kidneys were enlarged on palpation. There were increased concentrations of calcium (3.01 mmol/l), parathormone (2.0 ng/l), carcinoembryonic antigen (13.5 micrograms/l) and TPA (69 U/l). Computed tomography demonstrated cystic and solid parts of much enlarged kidneys. Biopsy revealed a poorly differentiated clear-cell renal carcinoma. Further information concerning the previously removed brain tumour showed this to have been an haemangioblastoma of the cerebellar tonsils indicating the diagnosis of v. Hippel-Lindau disease. Nine other family members had been affected, but none had the full-blown picture of the disease. The patient died 3 weeks later from the rapidly advancing tumour. Autopsy showed the bilateral renal carcinoma, bilateral phaeochromocytoma and metastases to the sternum, femurs, vertebrae and liver.

Adrenal Gland Neoplasms↗
PubMed1995

[A new laser puncture guidance device for CT- and MRT-guided punctures of the trunk].

A stereotactic device was developed to facilitate CT- or MR-guided punctures of the body. The correct needle angulation is checked by the reflection of fan-shaped red and green laser beams upon the needle. Due to its principle of function and design the device has considerable advantages: The puncture angle can be controlled in three dimensions. The freedom of movement within the operation area will not be affected. The device does not have to be permanently installed and can be employed in MRI at any field strength. Furthermore, all kinds of puncture instruments can be used.

Biopsy, Needle↗
PubMed1995

[Digital picture archiving, processing and communication in diagnostic imaging with a Siemens Network (SIENET): initial results].

The concept of Picture Archiving and Communication System (PACS) in digital imaging offers substantial advantages: better data security, faster access to archived images, simultaneous availability of images at different sites, minimal space demand for archive medium, retrospective image post-processing opportunities and lower costs resulting from reduced film consumption and length of stay. However, practical experiences concerning reliability and efficiency of real PAC networks in radiological departments have to be made yet in order to improve network structure, software design and hardware performance. The ongoing stepwise installation and test of a Siemens PACS (SIENET) at the Department of Radiology at the Medical University of Lübeck will support the introduction of PACS concept into radiological practice.

Computer Communication Networks↗
PubMed1994

[Densitometry in suspected preclinical osteoporosis: quantitative computerized tomography versus dual energy roentgen absorptiometry].

The bone mineral density of 85 patients with suspicion of a preclinical osteoporosis was measured at the lumbar spine by using quantitative computed tomography (QCT) in single-energy technique (SEQCT) and dual-energy technique (DEQCT) as well as by using dual-energy X-ray absorptiometry (DEXA). Additionally, the bone density of 63 of these patients was measured at the left femoral neck using DEXA. DEQCT und DEXA of the lumbar spine showed only a moderate correlation (R = 0.75) and differed considerably concerning the classification of the patients as normals or individuals with a mineral deficit when compared with age-matched normals (relative mineral deficit). The DEXA proved to be susceptible to degenerative alterations of the lumbar spine. Because of the extremely low dose of radiation and the good reproducibility the DEXA could nevertheless be recommended as a method for the long-time progress control especially for younger patients. SEQCT and DEQCT showed a very strong correlation (R = 0.98). The SEQCT with its lower dose of radiation should be sufficient for a long-time progress control and in many cases also for the initial diagnostics. Significant but only moderate correlations were found between the bone density at the femoral neck and the DEXA or DEQCT results (R = 0.68 respectively R = 0.63) for the lumbar spine, so that the linear regression did not render any useable approximations. Sufficiently exact information about the mineralization status of a certain skeletal site can only be obtained by direct measurement.

Absorptiometry, Photon↗
PubMedDate not supplied

MR-guided placement of a temporary vena cava filter: technique and feasibility.

The purpose of this paper was to investigate the feasibility of MR-guided insertion of a temporary vena cava filter on an open low-field imager. In vivo procedures were performed on four anesthetized pigs using a common nonferromagnetic temporary vena cava filter and a special prototype guidewire developed for vascular interventions guided by low-field MRI. Breath-hold spoiled gradient-echo sequences (fast low-angle shot [FLASH]) with flow compensation were used for position monitoring of the passively visualized intravascular devices. Using the described technique and equipment, all steps of the procedure were feasible in the MR unit. Practicability of the procedure seems to be sufficient for clinical purposes but was inferior compared to the conventional technique of filter placement.

Animals↗
PubMedDate not supplied

Visualization of magnetic resonance-compatible needles at 1.5 and 0.2 Tesla.

PURPOSE: For two types of passively visualizable magnetic resonance (MR)-compatible needles, the size of susceptibility artifacts was investigated at 0.2 and 1.5 Tesla (T) and assessed regarding their suitability for needle visualization. METHODS: Phantom trials were performed using T1-weighted spin echo (SE), turbospin echo (TSE) and gradient echo (GE) sequences and different angles beta between the needles and the main magnetic field (B0). RESULTS: Depending on the needle angle beta and the applied pulse sequence, we found artifact diameters of 0-9.7 mm employing SE, of 1.7-9.4 mm employing TSE, and of 1.4-20.6 mm employing GE at 1.5 T. At 0.2 T, we found artifact diameters of 0-5.7 mm employing SE, of 0-6.3 mm employing TSE, and of 0-11.3 mm employing GE. CONCLUSION: Comparing artifact sizes at 1. 5 T and 0.2 T, low field strength is superior for passive visualization of the needles tested-especially if GE imaging is performed.

Artifacts↗