閉塞性腎疾患に対する99mTc-DTPA利尿レノグラム, 99mTC -DMSAレノシンチによる評価

Abstract

種々の原因による閉塞性腎疾患48例51腎に対し, IVP, 99mTc-DTPA利尿レノグラム, 99mTc-DMSAレノシンチグラフィーを施行した.1)利尿レノグラムのパターンが1→3a→3b→4となるに従い, 水腎臓症の程度は高度になった(P<0.005).利尿レノグラムのパターンは尿流障害の程度を示す良い指標であると考えた.2)水腎症の程度が高度になるに従い, 99mTc-DMSA腎摂取率は低下したが有意ではなかった.3)利尿レノグラムのパターンと99mTc-DMSA腎摂取率との関係では2a型は有意に腎摂取率は低かった.3aと3b型をあわせた3型の腎摂取率は1型に比し有意に低かったが, 3a, 3b間には有意差を認めなかった.4)O'Reillyの2型は基本的には低下した腎機能を示すものであり, 2a型は高度の腎機能障害を有するに対し, 2b型は疝痛発作後にみられるもので可逆性の機能障害である可能性が高い

99mTc-DMSA and diuretic 99mTc-DTPA renoscintigraphy were performed on 51 kidneys suspected of obstructive nephropathy based on excretory urography to evaluate the residual renal function and the degree of urinary flow impairment respectively. We classified the response to diuretics into 6 patterns: I. normal, IIa. severely damaged renal function, IIb. slow RI excretion without urinary tract visualization (pattern II had no response to furosemide), IIIa. rapid elimination of tracer from the obstructed upper tract, IIIb. slow elimination, and IV. gradual tracer accumulation in the pelvicalyceal system with fairly well preserved renal function but no response. Hydronephrosis varied according to pattern type, in the ascending order of I, IIIa, IIIb and IV (p less than 0.05). Degree of hydronephrosis was inversely related to 99mTc-DMSA uptake, but without statistical significance. 99mTc-DMSA uptake was lower for pattern III as a whole (IIIa + (IIIb) than for pattern I (p less than 0.005), but there was no difference between IIIa and IIIb. Pattern IIa exhibited a significantly lower uptake than any of the other groups. (p less than 0.005) In contrast to previous views, we believe that pattern IIIa indicates a mild obstruction of urinary flow and impaired renal function. Consequently, assessment of obstructive nephropathy should not be based only on urodynamic study but also on differential renal function test.