Evaluation of renal first pass blood flow with a functional image technique in hypertensive patients

The renal circulation of patients with essential hypertension and renovascular hypertension was evaluated using ^99mTc-DTPA. The first renal peak count (the first C_max; FC_max), time phase distribution (the first T_max; FT_max), and blood velocity (the FC_max/FT_max) were calculated by digital imaging. This yields a visual image of the renal circulation. We consider that the increase in the renal first pass blood flow in patients with essential hypertension is best observed pixel by pixel. The FC_max and FC_max/FT_max images before and after treatment by percutaneous transluminal renal angioplasty in patients with renovascular hypertension clearly show its therapeutic effect. The FI technique, therefore, has the advantage that it can be performed at the same time as the conventional routine examinations of renal function. This makes it very useful clinically.