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Heterogeneity of renal cortical circulation in hypertension assessed by dynamic computed tomography
S Kojima1, Y Yoshitomi, M Yano
1Department of Clinical Research, Tohsei National Hospital, Shizuoka, Japan. kojima@fuji-mt.or.jp
Insights
Heterogeneity in renal cortical circulation, measured by dynamic computed tomography (CT), is significantly increased in hypertensive patients. This finding suggests a potential new indicator for early detection of renal circulatory issues.
Area of Science:
- Nephrology
- Radiology
- Cardiovascular Science
Background:
- Renal cortical circulation heterogeneity is a potential indicator of kidney health.
- Dynamic computed tomography (CT) offers a method to visualize and quantify this heterogeneity.
Purpose of the Study:
- To assess renal cortical circulation heterogeneity using dynamic CT.
- To investigate the relationship between this heterogeneity and hypertension.
Main Methods:
- Dynamic CT was performed on 125 patients.
- The coefficient of variation of CT numbers in the renal cortex was calculated as an index of heterogeneity.
- Patients were categorized into hypertensive and normotensive groups.
Main Results:
- Hypertensive patients (n=48) showed significantly greater heterogeneity (P < .001) than normotensive subjects (n=77).
- The heterogeneity index correlated positively with patient age and renal surface irregularity.
- A significant relationship was observed between heterogeneity and serum creatinine levels (r = 0.367, P < .0001).
Conclusions:
- Increased renal cortical circulation heterogeneity is associated with hypertension.
- This parameter may serve as a sensitive indicator for early renal circulatory deterioration and is linked to aging.
Abstract:
The aim of this study was to assess the grade of heterogeneous disturbance in the renal cortical circulation using dynamic computed tomography and to investigate the relationship between the heterogeneity of renal cortical circulation and hypertension. We studied 125 patients who underwent dynamic computed tomography (CT) for various abdominal diseases and had no serious hemodynamic abnormalities. In dynamic computed tomography under appropriate conditions, each pixel (image element), less than 1 mm2, has a CT number that is in proportion to the concentration of contrast media, which reflects the blood volume in the pixel. The image was constructed at the hilus level about 50 s after the start of a continuous infusion of contrast medium. The mean and standard deviation were calculated from the CT numbers in the renal cortex. The coefficient of variation, ie, the standard deviation divided by the mean value, was used as the index of the heterogeneity of renal cortical circulation. The coefficient of variation was significantly (P < .001) greater in the hypertensive patients (n = 48, 0.174 +/- 0.006 [mean +/- SE]) than in normotensive subjects (n = 77, 0.140 +/- 0.004). The coefficient increased in parallel with the patient's age and with the grade of renal surface irregularity. In the patients whose serum creatinine levels were normal, this parameter also had a significant relationship (r = 0.367, P < .0001) with serum creatinine. These results suggest that the heterogeneity of renal cortical circulation is increased in hypertension and is also associated with aging. This parameter may become a sensitive indicator to detect slight deterioration in the renal cortical circulation.