Biomedical subjects

T Bauermann

Publications and source records attributed to T Bauermann.

3 recordsLinked to original sources

PubMed1996

Improved resolution of magnetic resonance microscopy in examination of skin tumors.

Magnetic resonance imaging has become increasingly important for visualization and tissue differentiation of internal organs. Because of limited resolution, investigation of skin has been of little diagnostic value so far. We combined a homogeneous magnetic field of 9.4 T, as used in magnetic resonance spectroscopy, with gradient fields of 11.7 G/cm and an imaging unit to obtain a voxel resolution of 40 x 40 x 300 microm(3). With this magnetic resonance microscopy unit, we studied normal skin, 12 nevocellular nevi, 20 basal cell carcinomas, 8 melanomas, and 8 seborrheic keratoses after excision in vitro. The specimens were visualized in spin-echo images. The proton relaxation times T1 and T2 were determined for the different skin layers and tumor tissues. Interpretation of the spin-echo images was based on comparison with the correlating histology. Epidermis, dermis, subcutaneous tissue, and hair follicle complexes could be distinguished. Stratum corneum and hairs emitted no signal. All tumors presented as distinct, signal-rich, homogeneous structures within the dark, signal-poor dermis. Their shape corresponded to their outline in the histologic sections. Buds of superficial basal cell carcinomas could be resolved. The proton relaxation times T1 and T2 were significantly different among all skin layers and tumors. Our results demonstrate that with sufficient resolution, differentiation of skin tumors is possible using magnetic resonance imaging.

Adult↗

PubMed1993

Changes of soft-tissue water examined with magnetic resonance and electrical impedance tomography: an in vivo experiment.

The purpose of this study was the examination of short-term changes in soft-tissue water under in vivo conditions. In 12 healthy volunteers the water distribution of a selected slice of the lower limb was examined after change of position and rapid infusion of 0.9% saline solution. Two methods were used for data acquisition: magnetic resonance imaging (MRI) (Repetition Time (TR) = 1600 msec, Inversion Time (TI) = 300 msec, Echo Time (TE) = 22 msec) and electrical impedance tomography (EIT). In orthostatic equilibrium all 12 volunteers demonstrated changes of MR signal intensity and resistivity in the range of 12% and 7%, respectively. After infusion, mean changes of signal intensity and resistivity were 7% and 4%, respectively. The overall correlation of MRI and EIT was -0.96 (p < 0.001). Results indicate that inversion recovery sequences are a sensitive method of detecting in vivo changes of water distribution in selected areas of the body.

Adult↗

PubMedDate not supplied

MR relaxometry: estimating overhydration in renal failure.

An MR method is described for estimating overhydration in patients suffering from renal failure. In 29 healthy volunteers, the fat content of a selected slice of the lower limb was correlated to the overall T1-relaxation time (r = -0.97, p < 0.000001). When compared with the normal T1 of the voluntary group, delta T1 was calculated having regard to the individual fat content in 74 MR studies of 22 overhydrated patients. MR results were correlated with the difference between clinically estimated dry and the actual body weight (r = 0.6, p < 0.000001). In an intraindividual follow-up (11 studies) MRI was shown to provide good correlation to the actual body weight (r = 0.9, p < 0.0005) and fluid balance (r = 0.87, p < 0.001).

Adipose Tissue↗