Dynamic Gd-DTPA-enhanced MR imaging of the kidney: comparison between T1- and T2-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 TurboFLASH (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 stenosis was confirmed by conventional angiography.

RESULTS

During the early phase, the marked signal increase in T1-weighted imaging in the renal cortex corresponded to a similar marked decrease in signal intensity in T2-weighted imaging. During the middle and late phases, the medulla was dramatically decreased in intensity on the T2-weighted imaging resulting in a good contrast between the cortex and medulla.

CONCLUSION

Both sequences may provide almost similar information about the renal cortical blood flow. However, T2-weighted dynamic MR imaging may be more informative than T1-weighted dynamic MR imaging about the concentrating ability in the renal medulla. A high concentration of Gd-DTPA in the tubular structure was suspected to cause a dramatic decrease in intensity in the medulla in T2-weighted imaging.