Fifty children between 3 months postnatal and 16 years of age were examined by means of a 1.5 T superconductive magnet, run at 0.35 and 1.0 T. The myelination was studied qualitatively and quantitatively (relaxation times, proton densities, image contrast). With increasing age, a decrease of T1 and proton density of white matter was found, which was complete at one year of age. In regions with a slow progression of myelination, gray/white matter contrast showed an increase up to the end of the first decade. Pathological white matter maturation was diagnosed either as an abnormal transformation of myelin (characterized by abnormal relaxation values), or as a deficient or delayed myelin formation (in comparison with age-matched controls).

The knees of 20 patients with evidence of meniscal tears were examined via high-resolution computed tomography (HRCT); 10 of these were studied by MRI. The HRCT study was performed directly after double-contrast arthrography (AG). For comparison with HRCT, slice orientation for MRI examination was in transverse view; gradient echo sequences using the FISP technique were applied instead of spin echo sequences. All results were correlated to the arthroscopy (AS) findings. In 95% of the cases AG and AS results agreed, HRCT/AS in 85% and MRI/AS in 70%. In certain cases HRCT provided additional information which influenced appropriate surgical treatment. MRI is a noninvasive nonionising method but gives a less exact documentation of the lesion than AG and HRCT. The gradient echo mode is superior to the SE mode in respect of outlining meniscal structures, at least in transverse view.

The signal characteristics of 14 shockwave-treated and 14 solid control tumors were studied before and after injection of Gd-DTPA in an animal model. T1-weighted images of shockwave-treated tumors documented no significant signal intensity increase after contrast media injection in comparison with the untreated control tumors. The reduction of perfusion in shockwave-treated tumors can be documented in vivo by the signal intensity changes of the tumors after contrast media injection.

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