DYNAMIC GD-DTPA-ENHANCED MR-IMAGING OF THE KIDNEY - COMPARISON BETWEEN T1-WEIGHTED AND T2(ASTERISK)-WEIGHTED SEQUENCES

Objective: To determine whether T1- or T2-weighted sequences are more informative and practical in dynamic Gd-DTPA-enhanced MR imaging for the evaluation of renal blood flow and function. Materials and Methods : Dynamic Gd-DTPA-enhanced MR imaging of the kidney was performed in 7 patients by either T1-weighted TurboFLBSH (TR/TE/TI/FA = 9/4/27/8) or T2-weighted FLASH (TR/TE/FA = 32/22/10) sequences for comparison of the enhancement pattern. None of the subjects had a suspicion of renal dysfunction from laboratory data, and the absence of renal artery ste nosis was confirmed by conventional angiography. Results: During the e arly phase, the marked signal increase in T1-weighted imaging in the r enal cortex corresponded to a similar marked decrease in signal intens ity in T2-weighted imaging. During the middle and late phases, the me dulla was dramatically decreased in intensity on the T2-weighted imag ing resulting in a good contrast between the cortex and medulla. Concl usion: Both sequences may provide almost similar information about the renal cortical blood flow. However, T2-weighted dynamic MR imaging m ay be more informative than T1-weighted dynamic MR imaging about the c oncentrating ability in the renal medulla. A high concentration of Gd- DTPA in the tubular structure was suspected to cause a dramatic decrea se in intensity in the medulla in T2-weighted imaging.