Precursor of renal scarring: Cortical perfusion change or Cortical defect or Photon defect

Transcription

1 Usefulness of Intravoxel Incoherent Motion (IVIM) MR Imaging to Evaluate Cortical Defects in the first episode of Upper Urinary Tract Infections: Can IVIM DWI Replace the DMSA Scintigraphy? Poster No.: C-0952 Congress: ECR 2014 Type: Scientific Exhibit Authors: C. H. Lee, Y. S. Park, J. Lee, J. W. Choi, K. A. Kim, C. M. Park; Seoul/KR Keywords: Comparative studies, MR-Diffusion/Perfusion, MR, Pediatric, Kidney, Infection DOI: /ecr2014/C-0952 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 15

2 Aims and objectives INTRODUCTION Acute febrile urinary tract infection (UTI) Common in pediatrics Upper UTI with Vesicoureteral reflux # "renal scarring" # HTN, glomerular sclerosis, Chronic renal failure Precursor of renal scarring: Cortical perfusion change or Cortical defect or Photon defect Early detection of renal scarring # antibiotic prophylaxis # reversibly decrease the incidence of cortical perfusion change Fig. 1: DMSA scintigraphy demonstrated a photon defect. Page 2 of 15

3 Cortical Defect: Focal decrease of renal perfusion due to edema # Venous compression and intravascular granulocyte aggregation # Arteriolar and venous occlusion # identified as photon defect or perfusion defect Modality for detection of Cortical defect: US, CT, MRI, DMSA Current SOR: DMSA N Engl J Med 2003;348(3):195 Page 3 of 15

4 Fig. 2: DMSA scintigraphy demonstrated a photon defect. Page 4 of 15

5 Imaging Modalities for Cortical defect CE-CT: Radiation, CM CE-MRI: CM DMSA: Radiation Patients First Safety First Children First & Our Hope IVIM-DWI Apparent diffusion coefficient (ADC) Variable combinations of diffusion and perfusion effects, depending on the acquisition parameters Concept of IVIM (Intravoxel incoherent motion) True molecular diffusion (D): Largely depends on the cell density Pseudo-diffusion or perfusion (D*) Incoherent motion of water molecules by capillary networks Depends on tumor vascularity Le Bihan et al. Radiology 1988,168:497 Sigmund EE et al. Radiology 2012,263:758 Page 5 of 15

6 Fig. 3: 6 month-old boy with Acute febrile upper UTI (A) Coronal T2, (B) DMSA scintigraphy, (C) Axial ADC, (D,E) color-coded ADC map show a low signal defect (arrow) in the lower pole of the left kidney. Wedge-shaped photon defect-like lesion on the ADC postulated that IVIM DWI might evaluate the cortical scar change PURPOSE To compare the predictive value of IVIM DWI MRI with DMSA for the evaluation of acute febrile upper UTI in pediatric patients. To evaluate Diffusion parameters (ADC, D, D*, F) in both defect and nondefect renal tissue in upper UTI patients Page 6 of 15

7 Methods and materials Subject Retrospective study Period: June 2011 ~ Jan 2012 Search Keywords: "Acute Pyelonephritis (APN)", "Febrile UTI", "DMSA", "MRI", "Pediatrics", "DWI", and "Kidney" Diagnosis Criteria of acute febrile UTI Positive urine culture Leukocytosis Fever CRP: higher than 15 mg/l ESR: faster than 20 mm/h Table 1 Page 7 of 15

8 MRI: 3.0-T unit (Magnetom Trio a Trim; Siemens) 3. Coronal HASTE: TR/TE / ms; FA150º; matrix ; 3 mm ST Axial Blade T2 WI: TR/TE eff 3080/113 ms; FA 140 ; six evenly spaced rotating "blades" of ETL 35; 93.3% k-space coverage; 60% intersection gap; FOV mm; matrix ; voxel size mm; receiver bandwidth 363 Hz/pixel; one signal average; acquisition time of 1 min 34 sec Precontrast Radial GRE T1 WI: TR/TE, 3.6/42ms; FA, 10 ; ST, 3.0 mm; gap, 20%; mean number of slices, 80 ± 156; range, slices; FOV, 380 mm; matrix size, ; acquisition time, 1 min 24 seconds Diffusion weighted single shot EPI (DWI ): Axial/Coronal TR/TE, 3420/57; flip angle, 90º; matrix size, ; slice thickness, 4/3.5mm; no gap; Ac Time, 3 min 36 sec b-value = 0, 25, 50, 75, 100, 200, 500 and 800 s/mm2 Free breathing Intravoxel incoherent motion (IVIM)-DWI Calculated by software based on the prototype IVIM post-processing tool (Siemens) and MATLAB (Mathworks, USA). Sb/S0 = (1 - f) exp(-bd) + f exp[-b(d + D*)] Using fully bi-exponential non-linear curve fitting b, diffusion gradient strength; S0, signal intensity without a diffusion gradient; Sb, signal intensity at a given b value D : pure diffusion coefficient D*: perfusion-related incoherent microcirculation F : microvascular volume fraction SEDATION Chloral hydrate (50mg/kg) : orally for sedation, 30 minutes prior to MR During imaging, the attending pediatric physician monitored the infant, and vital sings were monitored continuously DMSA A dose of 5 MBq/kg Gamma camera (300 General Electric, Infinia, USA) using a low energy high-resolution collimator and a pixel dimension of 3-8 mm Page 8 of 15

9 3. 4. An experienced senior radiologist with 25 years of experience Acute photon defect: if at least one area of decreased focal or diffuse cortical uptake of DMSA was noted, with the renal outline preserved. MR Image Analysis Detection of cortical defect : presence of low SI axial & coronal ADC map # comparing DMSA Quantitative measurement of diffusion parameters 3. ROIs on both defect and non-defect areas Mean value of ADC, D, D*, f Three times on average Fig. 4 Statistical Analysis Diagnostic Sensitivity / Specificity: cross tab Page 9 of 15

10 Agreement btw IVIM DWI and DMSA, calculating kappa coefficient & McNemar test To compare the IVIM parameters btw the defect and non-defect groups: Mann-Whitney U test SPSS (version 20.0, Chicago, IL, USA) Results RESULTS Table 2: Comparison of IVIM DWI with Tc-99m DMSA Scintigraphy Sensitivity 93.3%, Specificity 100%, PPV 100%, NPV 96.5% Strength of agreement between IVIM DWI and DMSA findings: very good (K0 94.8%, p < 0.05) Page 10 of 15

11 Table 3: Diffusion parameters in the defect and non-defect groups Data are means ± standard deviations. NS = not significant. Fig. 5: CASE 6 month-old boy with Acute febrile upper UTI Axial ADC, color-coded ADC map, and coronal ADC show a low signal defect in the lower pole of the left Page 11 of 15

12 kidney. DMSA scintigraphy demonstrated a photon defect in the same area. After low-dose antibiotic treatment, the low signal defect decreased on the 6-month follow up ADC axial & coronal maps. The photon defect also decreased in follow-up DMSA scintigraphy. Fig. 6: CASE 4 month-old girl with Acute febrile upper UTI Coronal ADC and D maps show focal low signal intensity in the upper pole of the left kidney with mean values of 038 and (x 10-3 mm2/sec), respectively. D* and f maps show heterogeneous hypointensity (mean, 12 x 10-3 mm2/sec, mean = 0.102, respectively). Logarithmic plot of biexponential signal decay (fitted curve in red) and calculated IVIM parameters (D, D*, and f) in the defect area. DMSA scintigraphy demonstrated a photon defect in the same area. After low-dose antibiotic treatment, the previous low-signal defect disappeared on the 6-month follow-up ADC map. The photon defect was not detected in follow-up DMSA scintigraphy. Page 12 of 15

13 Fig. 7: CASE 3. 2 month-old boy with Acute febrile upper UTI ADC and D maps show multifocal low-signal intensities in both kidneys with mean values of and (x 10-3 mm2/sec) in the large defect of right kidney, respectively. D* and f maps show heterogeneous hypointensity (mean, 37.7 x 10-3 mm2/sec, mean = 0.147, respectively). DMSA scintigraphy demonstrated a photon defect in the same areas. LIMITATIONS Limited number of patients Retrospective study No other modality for standard of reference Not use a breath hold technique for DWI Conclusion Page 13 of 15

14 CONCLUSION IVIM 3. Safety: Radiation-free, CM free High sensitivity and specificity Quantitative evaluation for the defect ADC and D (pure diffusion) were significantly lower in the defect area than the non-defect area IVIM-DWI MRI might be used as the initial imaging modality for the evaluation of the cortical defect in pediatric upper UTI patients. Personal information References Majd M, Rushton HG, Jantausch B, Wiedermann BL. Relationship among vesicoureteral reflux, P-fimbriated Escherichia coli, and acute pyelonephritis in children with febrile urinary tract infection. J Pediatr 1991;119(4): American academy of pediatrics. Committee on quality improvement. Subcommittee on Urinary Tract Infection. Practice parameter: the diagnosis, treatment, and evaluation of the initial urinary tract infection in febrile infants and young children. Pediatrics 1999;103: Hoberman A, Charron M, Hickey RW, Baskin M, Kearney DH, Wald ER. Imaging studies after a first febrile urinary tract infection in young children. N Engl J Med 2003;348(3): Inoue T, Kozawa E, Okada H, et al. Noninvasive evaluation of kidney hypoxia and fibrosis using magnetic resonance imaging. J Am Soc Nephrol 2011;22(8): Majd M, Nussbaum Blask AR, Markle BM, et al. Acute pyelonephritis: comparison of diagnosis with 99mTc-DMSA, SPECT, spiral CT, MR imaging, and power Doppler US in an experimental pig model. Radiology 2001;218(1): Lavocat MP, Granjon D, Allard D, Gay C, Freycon MT, Dubois F. Imaging of pyelonephritis. Pediatr Radiol 1997;27(2): Page 14 of 15

15 7. Kovanlikaya A, Okkay N, Cakmakci H, Ozdogan O, Degirmenci B, Kavukcu S. Comparison of MRI and renal cortical scintigraphy findings in childhood acute pyelonephritis: preliminary experience. Eur J Radiol 2004;49(1): Thoeny HC, De Keyzer F, Oyen RH, Peeters RR. Diffusion-weighted MR imaging of kidneys in healthy volunteers and patients with parenchymal diseases: initial experience. Radiology 2005;235(3): Togao O, Doi S, Kuro-o M, Masaki T, Yorioka N, Takahashi M. Assessment of renal fibrosis with diffusion-weighted MR imaging: study with murine model of unilateral ureteral obstruction. Radiology 2010;255(3): Xu X, Fang W, Ling H, Chai W, Chen K. Diffusion-weighted MR imaging of kidneys in patients with chronic kidney disease: initial study. Eur Radiol 2010;20(4): Le Bihan D, Breton E, Lallemand D, Aubin ML, Vignaud J, Laval-Jeantet M. Separation of diffusion and perfusion in intravoxel incoherent motion MR imaging. Radiology 1988;168: Sigmund EE, Vivier PH, Sui D, et al. Intravoxel incoherent motion and diffusiontensor imaging in renal tissue under hydration and furosemide flow challenges. Radiology 2012;263(3): Rheinheimer S, Stieltjes B, Schneider F, et al. Investigation of renal lesions by diffusion-weighted magnetic resonance imaging applying intravoxel incoherent motionderived parameters--initial experience. Eur J Radiol 2012;81(3):e Piepsz A, Blaufox MD, Gordon I, et al. Consensus on renal cortical scintigraphy in children with urinary tract infection. Scientific Committee of Radionuclides in Nephrourology. Semin Nucl Med 1999;29(2): Page 15 of 15