Zengoro Onouchi

Delayed contrast enhancement in acute focal bacterial nephritis: CT features.

Computed tomography was performed in seven patients with acute pyelonephritis 6 h after the administration of contrast medium. Four patients revealed patchy wedge-shaped areas of contrast enhancement. The scans immediately after contrast medium administration showed decreased attenuation in these wedge-shaped areas. These results suggest that CT performed hours after contrast medium administration may reveal delayed enhancement in a significant number of patients with acute pyelonephritis.

Sex differences in acquired cystic disease of the kidney on long-term dialysis.

Acquired cystic disease of the kidney in chronic glomerulonephritic patients who had been on hemodialysis more than 3 years (4.5 +/- 1.2 years at the base line examination), were followed for 3.6 +/- 0.5 years (at the follow-up examination) by computed tomography (CT scan). The renal volume in the 25 male patients was significantly greater at the follow-up examination than at the base line examination. On the other hand, the renal volume in the 12 female patients was similar on both examinations. The enlargement of kidney volume more than twofold during the follow-up was seen in 9 of 25 male and none of 12 female patients. The grade of cystic transformation was increased in male patients during the follow-up period. These results indicate that sex-related endogenous substances might play a role in the pathogenesis of acquired cystic disease.

Renal cortex visualization and analysis of dynamic CT curves of the kidney.

Renal cortex visualization and dynamic renal computed tomography (CT) were carried out by bolus injection of contrast medium. In vivo renal cortex visualization showed that renal cortex volume and cortex thickness are both inversely correlated with age. The percentage volumes of cortex and columns of Bertin are correlated inversely in non renal-failure subjects. Percentage volumes of cortex tend toward low values in renal failure and status after renal transplantation. In analyzing dynamic renal CT curves, the corticomedullary junction time is a good index of mild impairment of renal function.

Evidence for Patchy Renal Vasoconstriction in Man: Observation by CT Scan

We report the first demonstration of patchy vasoconstriction of the kidney in man, together with temporary impairment of renal function. Observations were made by computerized tomography (CT scan). Such vasoconstriction might occur during the mild form or the recovery phase of acute renal failure.

Dynamic computed tomography in acute renal failure: analysis of time-density curve.

An analysis of dynamic CT curves in 12 patients with acute renal failure was performed. An oliguric patient who demonstrates corticomedullary differentiation on CT images will develop diuresis within 4 days. A corti-coaortic junction time of more than 180 s associated with no differentiation between cortex and medulla is associated with prolonged oligoanuria. Impending diuresis is heralded by a corticoaortic junction time of less than 180 s. These preliminary results suggest that an analysis of dynamic CT curves in acute renal failure can predict the time of appearance of the diuretic stage.

Persistent wedge-shaped contrast enhancement of the kidney

A case with a single wedge-shaped high-density area of the kidney that persists after urography was observed by CT scan. This might be an aberrant form of acute renal failure with multiple wedge-shaped contrast enhancement.

Changes of the hepatic CT absorption value in hemodialysis patients

The effect of hemodialysis on the CT absorption value of the liver was examined in 14 hemodialysis patients. In the high ultrafiltration group [10 patients with a weight loss of −1.7 to −3.5 (2.9 ± 0.6) kg], the hepatic CT absorption value increased from 49.6 ± 7.0 to 58.7 ± 8.7 Hounsfield units (p < 0.001) during hemodialysis. The increase in hepatic CT absorption value during dialysis correlated with the weight loss (p < 0.001, r = 0.798). A 5.3% body weight loss by ultrafiltration resulted in an 18.5% increase in the CT absorption value of the liver. This study suggests that one should be careful in making an early diagnosis of hepatic disease, especially hemosiderosis, in hemodialysis patients based on the hepatic CT absorption value because it is affected by hemodialysis.