Correlation between choline level and Gd-DTPA enhancement in patients with brain metastases of mammary carcinoma

Single voxel 1HH double spin-echo MR spectroscopy was used to examine 15 cases of brain metastasis of mammary carcinoma (18 lesions) in relation to Gd-DTPA enhanced MR imaging. For lesions larger than 50% of MRS voxel size, there was significant correlation between Gd-DTPA-enhanced MRI signal and MRS-detected signal of choline (Cho) containing compounds (r = 0.86, P < 0.01; n = 8). The observed loss of correlation when including the smaller lesions was overcome by correcting for partial volume effects (r = 0.69, P < 0.002; n = 18). Metastasis spectra showed increased Cho compared with control spectra, except for those lesions showing detectable lactate (Lact) signal. The detection of Lact in four of the larger lesions coincided with comparatively low levels of creatine (Cr) and Cho and heterogeneous Gd-DTPA enhancement (ring-enhancement). It was concluded that in brain metastases of mammary carcinoma Lact represents a product of ischemia preceding/during tissue decay resulting in central necrosis, rather than tumor specific metabolism resulting in increas

Sequential MR imaging of denervated and reinnervated skeletal muscle as correlated to functional outcome

Purpose: To prospectively assess the short inversion time inversionrecovery (STIR) magnetic resonance (MR) signal intensity changes of denervated and reinnervated skeletal muscle over time in clinical patients. Materials and Methods: This study was approved by the institutional review board, and informed consent was obtained from all patients. Twenty-three patients with complete traumatic transection of the median or ulnar nerve in the forearm were prospectively followed for 12 months after surgical nerve repair. STIR MR images of selected intrinsic hand muscles were obtained 1, 3, 6, 9, and 12 months after nerve repair, and signal intensities of denervated and reinnervated muscles were measured semiquantitatively. After 12 months, hand function was assessed. Signal intensity ratios were correlated to functional outcome with analysis of variance. Results: Of the 23 patients, 10 had good function recovery, while 13 had poor recovery. For the group with good function recovery, mean signal intensity ratios of 1.267 ± 0.060 (standard deviation), 1.357 ± 0.116, 1.297 ± 0.111, 1.205 ± 0.096, and 1.086 ± 0.104 were found at 1-, 3-, 6-, 9-, and 12-month follow-up, respectively. In the group with poor recovery, mean signal intensity ratios of 1.299 ± 0.056, 1.377 ± 0.094, 1.419 ± 0.117, 1.398 ± 0.111, and 1.342 ± 0.095 were found at 1-, 3-, 6-, 9-, and 12-month follow-up, respectively. Comparison of the group with poor function recovery and the group with good function recovery showed significant differences at 6-, 9-, and 12-month follow-up (P = .035, P = .001, and P < .001, respectively), with normalizing signal intensities in the group with good function recovery and sustained high signal intensity in the group with poor function recovery. Conclusion: STIR MR imaging can be used to differentiate between denervated and reinnervated muscles for at least 12 months after nerve transection

Hydrogen magnetic resonance spectroscopy follow-up after radiation therapy of human brain cancer: Unexpected inverse correlation between the changes in tumor choline level

RATIONALE AND OBJECTIVES The anatomic and metabolic changes in human brain tumors treated by radiation therapy were compared using gadolinium–enhanced magnetic resonance imaging and hydrogen (1H) magnetic resonance spectroscopy. The study was intended to assess the potential of 1H magnetic resonance spectroscopy in monitoring response to therapy. METHODS Thirteen cases of brain cancer treated by radiation therapy were examined by 1H magnetic resonance spectroscopy and gadolinium–enhanced T1–weighted magnetic resonance imaging and reexamined at 2–month intervals. RESULTS Follow–up after radiation therapy showed changes in post–gadolinium magnetic resonance imaging contrast that are inversely correlated with the changes in choline level (r = –0.69, P 1H magnetic resonance spectroscopy to discriminate enhancing brain tumors with a high content of vital tumor cells (high choline) from tumors, combining decreased cell density with increased interstitial space (low choline)