Contrast-enhanced MRI Examinations Research Articles

MR tomographic monitoring of prostate carcinoma after cryotherapy: initial results

To assess the morphological changes in the prostate gland and adjacent tissue after cryosurgery by high resolution MRI in patients with histological proven prostatic carcinoma. 15 patients (mean age 66 years) with histologically proven prostate carcinoma underwent T2- and contrast-enhanced T1-weighted high-resolution MRI examinations with fat suppression. Follow-up MRI with an identical imaging protocol were performed at different time intervals (24-72 h, 2-6, 12, 26-52 weeks). Mean prostate volume had decreased by 30% in all patients 12-52 weeks after cryosurgery. After cryosurgery, zonal differentiation was lost in all patients with abnormalities in the periprostatic tissue in all patients, and rectal wall thickening in 47% of patients. Cryosurgery-induced changes in the prostate could not be differentiated from tumour recurrence. High resolution MRI allows precise recognition of intraprostatic and adjacent tissue alterations after cryosurgery of prostatic carcinoma. However, reliable detection of tumour recurrence was impossible due to cryosurgically induced signal changes.

High-resolution MRI of pancreatic masses with a new circularly polarized body phased-array coil.

A total of 18 patients with clinical suspicion of a pancreatic tumor underwent dynamic contrast-enhanced CT and MRI examinations. A fat-suppressed T1-weighted 2D fast-low-angle-shot (FLASH) sequence and a T2-weighted spin-echo (SE) sequence were applied in a transverse orientation using a circularly polarized (CP) body phased-array coil. The FLASH sequence was repeated after Gd-DTPA administration. The highest spatial resolution was 1.37 x 1.37 x 3.00 mm3. In two cases a half Fourier single-shot turbo-SE sequence (HASTE) was additionally applied. In a comparison between CT and MRI, pancreatic masses could be demonstrated and characterized with excellent image quality. The fat-saturated 2D FLASH sequence yielded the highest contrast-to-noise ratios after Gd-DTPA administration between pancreas and inflammatory or neoplastic lesion. One non-contour deforming carcinoma could be detected only with MRI and was only retrospectively visible on CT with an element of uncertainty. Magnetic resonance imaging using a CP body phased-array coil and fat-suppressed T1- and T2-weighted FLASH, SE, and turbo-SE sequences offers diagnostic possibilities in improved imaging of the pancreas.

Intracranial meningiomas

Fifty patients with intracranial meningiomas underwent plain and contrast-enhanced examinations with CT and MRI. Each of the MR studies consisted of three plain (T1, proton density and T2-weighted) and a post-contrast series (0.1 mmol Gd-DTPA/kg body weight). All techniques (plain CT, plain MRI, contrast-enhanced CT, contrast-enhanced MRI) proved to be highly efficient as regards tumour detection: depending on the technique, an intracranial lesion was demonstrated in 47-50 cases. The image contrast was assessed as good or excellent in 21 cases having plain CT and in 33 cases having plain MRI, but in 46 and 50 of the contrast-enhanced CT and MRI studies respectively. Adequate tumour delineation was achieved in 18 cases with plain CT, in 35 cases with plain MRI and in 46 and 50 cases of the contrast-enhanced CT and MRI examinations. The contrast-enhanced studies proved to be superior to the plain CT and MRI studies as regards image contrast and tumor delineation. Because of the methodological advantages of the MRI technique, contrast-enhanced MRI was judged to be slightly superior to contrast-enhanced CT.