Measurement of renal perfusion and blood flow with fast computed tomography.

Fast computed tomography (CT) is one of the few methods available to measure cortical and medullary renal blood flow (RBF) directly. Because these measurements are complicated by passage of the contrast medium into extravascular compartments, we used the residual opacity following the vascular blush as an index to account for extravascular iohexol. Kidneys of anesthetized dogs were examined in situ by fast CT following intra-aortic injections of iohexol. Perfusion was analyzed during a control period and three subsequent periods in which RBF was reduced by 10%, 30%, and 50%. Cortical microvascular distribution volume changed from 19.7 +/- 2.8% to 19.8 +/- 1.7%, 15.3 +/- 1.2%, and 9.9 +/- 1.7%, respectively, without significant alterations in cortical mean transit time. Microvascular distribution volume was divided by mean transit time to determine tissue perfusion. Cortical perfusion changed from 3.8 +/- 0.7 to 3.9 +/- 0.6, 3.1 +/- 0.5, and 2.2 +/- 0.5 mL.min-1.mL tissue-1. Total cortical blood flow (cortical perfusion multiplied by cortical volume) decreased from 164 +/- 32 to 159 +/- 31, 117 +/- 20, and 86 +/- 22 mL/min, respectively. Medullary microvascular distribution volume, mean transit time, perfusion, and total blood flow remained unchanged. Fast CT-determined total RBFs (cortex plus medulla) were similar to simultaneous electromagnetic flow measurements. These results indicate that renal regional perfusion is more dependent on the microvascular distribution volume than mean transit time and that variations in renal tissue perfusion with reduction of RBF are more apparent in the cortex than in the medulla.

[1]  E. Ritman,et al.  Intrarenal distribution of blood flow: evolution of a new approach to measurement. , 1984, Kidney international.

[2]  M Intaglietta,et al.  Capillary flow velocity measurements in vivo and in situ by television methods. , 1975, Microvascular research.

[3]  M. Lipton,et al.  Measurement of renal blood flow by cine computed tomography. , 1987, Kidney international.

[4]  M. Bell,et al.  The effect of a low-osmolar radiographic contrast medium on in vivo and postmortem renal size. , 1991, Investigative radiology.

[5]  C J Lumsden,et al.  Vascular exchange in the kidney. Regional characterization by multiple indicator tomography. , 1993, Circulation research.

[6]  C. Goresky,et al.  Capillary Exchange Modeling: Barrier-Limited and Flow-Limited Distribution , 1970, Circulation research.

[7]  R. Roman,et al.  Pressure‐Diuresis in Volume‐Expanded Rats Cortical and Medullary Hemodynamics , 1988, Hypertension.

[8]  M. Lipton,et al.  Attenuation Changes of the Normal and Ischemic Canine Kidney , 1985, Acta radiologica: diagnosis.

[9]  R. Roman,et al.  Laser-Doppler determination of papillary blood flow in young and adult rats. , 1986, The American journal of physiology.

[10]  Y. Abe.  Pressure‐Dependent Heterogeneity of Renal Cortical Blood Flow in Dogs , 1970, Circulation research.

[11]  F. Klocke,et al.  First‐Pass Entry of Nonionic Contrast Agent Into the Myocardial Extravascular Space: Effects on Radiographic Estimates of Transit Time and Blood Volume , 1991, Circulation.

[12]  R. Bowman,et al.  Measurement of renal cortical and medullary blood flow by laser-Doppler spectroscopy in the rat. , 1979, The American journal of physiology.

[13]  M. Bentley,et al.  Intrarenal mechanisms that regulate sodium excretion in relationship to changes in blood pressure. , 1989, Mayo Clinic proceedings.

[14]  J. H. Kinsey,et al.  Some Imaging Characteristics of the Dynamic Spatial Reconstructor X-Ray Scanner System , 1983 .

[15]  R A Karwoski,et al.  Estimation of tissue volume from serial tomographic sections. A statistical random marking method. , 1988, Investigative radiology.

[16]  A. Nygren,et al.  Effects of intravenous contrast media on cortical and medullary blood flow in the rat kidney. , 1988, Investigative radiology.

[17]  M. Brown,et al.  Effect of captopril on renal function in hypertensive dogs with unilateral renal artery stenosis, studied with radionuclide dynamic scintigraphy. , 1990, American journal of hypertension.

[18]  N. Mullani,et al.  First-pass measurements of regional blood flow with external detectors. , 1983, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[19]  R. Robb.  X-ray computed tomography: from basic principles to applications. , 1982, Annual review of biophysics and bioengineering.

[20]  R. Roman,et al.  Relationship between renal perfusion pressure and blood flow in different regions of the kidney. , 1993, The American journal of physiology.

[21]  U. Erikson,et al.  Regional renal function measured by videodensitometry. , 1981, Scandinavian journal of urology and nephrology.

[22]  E. Ritman,et al.  In Vivo Relation of Intramyocardial Blood Volume to Myocardial Perfusion: Evidence Supporting Microvascular Site for Autoregulation , 1992, Circulation.

[23]  M. Lipton,et al.  Cine‐CT Measurement of Cortical Renal Blood Flow , 1987, Journal of computer assisted tomography.

[24]  H. G. Swann,et al.  Relation of kidney size to blood pressure. , 1971, The American journal of physiology.

[25]  E. Hoffman,et al.  Three-dimensional canine renovascular structure and circulation visualized in situ with the dynamic spatial reconstructor. , 1988, The American journal of anatomy.

[26]  C. Starmer,et al.  Indicator Transit Time Considered as a Gamma Variate , 1964, Circulation research.

[27]  M. Fiksen-Olsen,et al.  Role of prostaglandins in the cortical distribution of renal blood flow following reductions in renal perfusion pressure. , 1987, Prostaglandins.

[28]  J. Hall.  Regulation of glomerular filtration rate and sodium excretion by angiotensin II. , 1986, Federation proceedings.

[29]  K. Hayakawa,et al.  Effects of contrast media on renal function and subcellular morphology in the dog. , 1986, Investigative radiology.

[30]  Erik L. Ritman,et al.  Dynamic spatial reconstructor: a high-speed, stop-action, 3-D, digital radiographic imager of moving internal organs and blood , 1991, Optics & Photonics.

[31]  C. Zurth.  Mechanism of renal excretion of various X-ray contrast materials in rabbits. , 1984, Investigative radiology.

[32]  B. Gewertz,et al.  Measurement of renal blood flow. , 1982, The Journal of surgical research.

[33]  F. Kiil,et al.  Determinants of renal cortical volume. , 1971, The American journal of physiology.

[34]  E L Ritman,et al.  Myocardial blood flow estimated by synchronous, multislice, high-speed computed tomography. , 1989, IEEE transactions on medical imaging.

[35]  P. Nilsson-ehle,et al.  Plasma clearance of a new contrast agent, iohexol: a method for the assessment of glomerular filtration rate. , 1984, The Journal of laboratory and clinical medicine.

[36]  R A Robb,et al.  Three‐Dimensional Spatial, Density, and Temporal Resolution of the Dynamic Spatial Reconstructor , 1982, Journal of computer assisted tomography.

[37]  M. Bell,et al.  Quantitation of the in vivo kidney volume with cine computed tomography. , 1990, Investigative radiology.

[38]  P. Probst,et al.  Experimental acute renal artery stenosis. Dynamic CT and renal perfusion. , 1984, Investigative radiology.

[39]  D. Hay,et al.  Ultrastructure of the developing vascular system in the puppy kidney , 1981, The Anatomical record.

[40]  M. Lipton,et al.  Cine-Computed Tomographic Assessment of Regional Renal Blood Flow , 1990, Acta radiologica.