title: Use of contrast-enhanced computed tomography to measure clearance per unit renal volume: a novel measurement of renal function and fractional vascular volume.
abstract: The iodinated contrast agents used for computed tomography (CT) have pharmacokinetics similar to inulin and can measure physiological indices, such as clearance per unit renal volume (alpha/V) and fractional vascular volume (fvv). Clinical experience with these techniques is, however, scanty, and the present study explored their potential in subjects with and without renal dysfunction. In a series of subjects, a single slice of kidney was scanned sequentially after the bolus injection of contrast material. Time-attenuation curves were constructed, and alpha/V and fvv were calculated using a Patlak graphic analysis. In the first part of the study, 50 normal kidneys in 35 subjects (aged 21 to 75 years) were studied. In the second stage, alpha/V was compared with glomerular filtration rate (GFR) measurements in 24 patients with diabetes (aged 28 to 84 years) with or without renal dysfunction. In normal kidneys, alpha/V averaged 0.49 +/- 0.11 mL/min/mL and fvv averaged 35% +/- 12%. These values agree with literature data obtained using other techniques. A negative correlation was seen between age and alpha/V (r = 0.66; P < 0.0001), but not fvv. In patients with diabetes, a strong correlation was observed between renal clearance values, calculated from CT and corrected for renal volume, and GFR (r = 0.87; P < 0.0001). Dynamic CT can provide quantitative renal physiological information on a regional basis noninvasively.
authors: Department of Imaging, National Defense Medical College, Saitama, Japan. yoshita@xa2.so-net.or.jp
authors: Y
authors: Y
authors: Tsushima
authors: M J
authors: MJ
authors: Blomley
authors: S
authors: S
authors: Kusano
authors: K
authors: K
authors: Endo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003404:Creatinine / Q000378:metabolism; D003920:Diabetes Mellitus / Q000000981:diagnostic imaging / Q000503:physiopathology; D003928:Diabetic Nephropathies / Q000000981:diagnostic imaging / Q000503:physiopathology; D005919:Glomerular Filtration Rate; D006801:Humans; D007455:Iodine; D007668:Kidney / Q000000981:diagnostic imaging; D007674:Kidney Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D007677:Kidney Function Tests / Q000379:methods*; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007455:Iodine; D003404:Creatinine