Glomerular filtration rate with MDCT Dr Laurent Juillard, MD, PhD Département de Néphrologie, H. E. Herriot Inserm ERI 22, Université de Lyon. Lyon, France
Outline Functional parameter definition Tools : EBCT Spiral CT MDCT Modeling methods Gamma variate Patlak Experimental data
The challenge of renal functional evaluation
Renal Functional Imaging MRI CT SCAN / EBCT MDCT Non invasive evaluation PET Split renal function Absolute quantification
Renal Functional parameters Tissue Injury CT, MR MR BOLD PET CT, MR Blood Flow Perfusion Oxygen content Oxydative metabolism GFR CT, PET REDUCTION Glomerular Filtration Rate
Electron Beam Computed-Tomography MDCT Gamma variate :»Glomerular filtration rate»renal blood flow»renal perfusion
Electron Beam Computed-Tomography EBCT cardiac and renal functional imaging Cortical and medulla volume Regional blood flow, tissue perfusion Glomerular filtration rate Split renal function Few evaluation in humans Breath control
EBCT: Principles High temporal resolution Good spatial resolution Multi slices
Krier et al AJP, 2001
EBCT: gamma variate INJECTION VVC : 0,5 ml/kg, 15 ml/s Krier et al AJP, 2001
METHODS Densité Corticale (HU) Cortical density (HU) 120 100 80 60 40 20 0 Renal blood flow Glomerular filtration rate Intratubular concentration Index 0 50 100 150 200 250 Time (s) Temps (s) Data Vasculaire Proximal Distal Total INJECTION VVC : 0,5 ml/kg, 15 ml/s
Krier et al AJP, 2001
Chade et al Circulation, 2001
Chade et al Circulation, 2001
PATIENTS Hypertension Unilateral RAS with FMD MR or Conventional angiography «Hemodynamically significant» US
Results: Regional Volumes Regional volume (cm3) Volume Régional (cm3) 45 40 35 30 25 20 15 10 5 0 * Sténose Stenosis Contra-lateral Kidney Contralateral Rein Cortex Medulla
250 200 150 100 50 0 Results: Blood Flow Cortex Medulla * Sténose Contra-lateral Rein Stenosis Kidney Contralateral Regional Blood Flow (ml/min) Débit Sanguin Rénal Régional (ml/min)
5 4 3 2 1 0 Results: Perfusion Cortex Medulla Sténose Contra-lateral Rein Stenosis Kidney Contralateral Regional perfusion Perfusion Régionale (ml/min/g) (ml/min/g)
Results: GFR Glomerular Flow Rate (ml/min) DFG (ml/min) 35 30 25 20 15 10 5 0 Stenosis Sténose Kidney Contro-lateral Rein Contralateral 1 2
Pelaez et al NDT, 2005
Pelaez et al NDT, 2005
MDCT : Principles Vs EBCT Identical parameters
Cortical TDC MDCT EBCT Daghini et al, Radiology, 2007
MDCT EBCT Medulla TDC Daghini et al, Radiology, 2007
Daghini et al, Radiology, 2007
Daghini et al, Radiology, 2007
14 patients with ARAS 14 patients with EH MRI BOLD for oxygen content MDCT study Gloviczki et al, Hypertension 2010
GFR?? Gloviczki et al, Hypertension 2010
Spiral CT Scanner Patlak : Glomerular filtration rate
Tsushima et al, AJKD 99
Tsushima et al, AJKD 99
Tsushima et al, AJR 01
Tsushima et al, AJR 01
Hackstein et al, Radiology 05
Hackstein et al, Radiology 05
Hackstein et al, Radiology 05
Patlak GFR Correlation between GFR Patlak and Creatinine clairance EDTA scintigraphy BUT ROI cortex AND medulla No comparaison with reference method Tsushima, AJKD, 1999 Dawson, Invest Radiol, 1993 Miles, Br J Radiol, 1999 Tsushima, AJKD, 1999 Hackstein, Eur Radiol, 2001
Daghini et al, Radiology, 2007 PATLAK
PATLAK r=0.12 PATLAK modified r=0.75 Daghini et al, Radiology, 2007 Gamma Variate r=0.79
PATLAK modified -29+/- 12 PATLAK Gamma Variate -12+/-10 Daghini et al, Radiology, 2007
Summary CT Most powerful method GFR, RBF, Perfusion, ICT, Volume But Remain invasive Contrast media toxicity
Validation of Renal Perfusion and Glomerular Filtration Rate measurement with MDCT and low rate CM Injection. Sandrine LEMOINE, Laurent JUILLARD
Aim Validation of the measurement of Cortical perfusion Glomerular filtration rate using MDCT With a low rate CM injection (3mL/s) and using a peripheral vein injection Using the gamma variate modeling Using fluorescent microspheres as a reference for RBF and Inulin clearance for GFR
Materiel et Methods Images dynamiques sur 144 secondes au niveau d une coupe du porc n 6 après injection de dopamine. Une image toute les secondes les 30 premières secondes puis une image toutes les 6 secondes
Materiel et Methods Régions d intérêt tracée manuellement
Materiel et Methods Vascular = Perfusion Proximal peak = GFR Gamma variate
Materiel et Methods 10 pigs Protocole: Dopamine 10 µg/kg/min Dopamine + SSI 10 µg/kg/min Angiotensine II (500ng/kg/min) MS 1 = Perf 1 MDCT: PERF 1 GFR 1 MS 2 = Perf 2 MDCT: PERF 2 GFR 2 MS 3 =Perf 3 MDCT: PERF 3 GFR 3 Sacrifice DFG 1 Urine + blood DFG 2 Urine + blood DFG 3 Urine + blood
Results Perfusion * NS NS * NS Perfusion scanner Perfusion microsphères NS Dopamine Dopamine + SSI Angiotensine II
Results Perfusion 6 5 P e r f u s i o n M D C T (m L.m in.-1.g -1 ) 4 3 2 1 y = 0,8421x + 0,2496 p<0.0001 R 2 = 0,8758 R = 0,93 0 0 1 2 3 4 5 6 Perfusion Microspheres Corrélation entre les mesures de perfusion (ml.min.-1.g-1) avec le scanner et avec les microsphères.
Results Perfusion Perfusion MDCT-MS 5 4 3 2 1 0-1 -2-3 -4-5 0,2 +/- 0,3 ml/min 0 1 2 3 4 5 6 Mean (ml/min/g)
Results GFR gamma variate GFR inuline (ml/min) 160 140 120 100 80 60 40 20 R 2 = 0,0006 0 0 10 20 30 40 50 60 GFR MDCT (ml/min) Corrélation entre les mesures de DFG mesurée avec la clairance de l inuline et avec le scanner.
Results GFR Patlak GFR Inulin (ml/min) 60 50 40 30 20 10 y = 0,4844x + 13,186 R 2 = 0,4192 0 0 20 40 60 80 Corrélation entre les mesures de DFG mesurée avec la clairance de l inuline et avec le scanner. GFR Patlak (ml/min)
Conclusion Most powerful functional imaging modality for quantitative assessment of renal performance Limits : CM toxicity and high rate injection for gamma variate Low rate injection : compartmental modeling to be tested for GFR