MR-visible brain water content in human acute stroke

Quantification of metabolite concentrations by proton magnetic resonance spectroscopy (H-1-MRS) in the human brain using water as an internal standard is based on the assumption that water content does not change significantly in pathologic brain tissue. To test this, we used H-1-MRS to estimate brain water content during the course of cerebral infarction. Measurements were performed serially in the acute, subacute, and chronic phase of infarction. Fourteen patients with acute cerebral infarction were examined as well as 9 healthy controls. To correlate with regional cerebral blood flow (rCBF) SPECT-scanning using Tc-99m-HMPAO as flow tracer was performed in the patients. Mean water content (SD) in the infarct area was 37.7 (5.1); 41.8 (4.8); 35.2 (5.4); and 39.3 (5.1) mol [kg wet weight](-1) at 0-3; 4-7; 8-21; and >180 days after stroke, respectively. Water content increased between Day 0-3 and Day 4-7 (p = 0.034) and decreased from Day 0-3 to Day 8-21 (p = 0.028). Water content at Day 4-7 was significantly higher than in controls (p less than or equal to 0.05). At the same time intervals, mean rCBF (SD) was 76 (23); 94 (31); 106 (35); and 64 (26)%, respectively. There was a significant increase in rCBF from Day 0-3 to Day 4-7 (p = 0.050) and from Day 0-3 to Day 8-21 (p = 0.028). No correlation between rCBF and water content was found. Water content in ischemic brain tissue increased significantly between Day 4-7 after stroke. This should be considered when performing quantitative H-1-MRS using water as an internal standard in stroke patients. (C) 1999 Elsevier Science Inc.