jksr Journal of the Korean Society of Radiology J Korean Soc Radiol 1738-2637 2288-2928 The Korean Society of Radiology 10.3348/jksr.2017.76.5.337 jksr-76-337 Original Article Analysis of the Effects of Different Iodine Concentrations on the Characterization of Small Renal Lesions Detected by Multidetector Computed Tomography Scan: A Pilot Study LeeHak JongMD 1 2 3 4 KimSang YounMD 1 2 3 5 6 ChoJeong YeonMD 1 2 3 5 6 HwangSung IlMD 1 2 3 4 MoonMin HoanMD 1 2 3 7 KimSeung HyupMD ∗ 1 2 3 5 6 Department of Radiology, Seoul National University College of Medicine, Seoul, Korea Kidney Research Institute, Seoul National University College of Medicine, Seoul, Korea Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea Clinical Research Institute, Seoul National University Hospital, Seoul, Korea Department of Radiology, Seoul National University Hospital, Seoul, Korea Department of Radiology, SMG-SNU Boramae Medical Center, Seoul, Korea Corresponding author: Seung Hyup Kim, MD Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea. Tel. 82-2-2072-2987 Fax. 82-2-743-6385 E-mail: kimshrad@snu.ac.kr 12017 712017 765 337345 28032016 31052016 01102016 Copyright © 2017 The Korean Society of Radiology 2017 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Purpose

Our objective was to compare the effects of different iodine concentrations on characterizing small renal lesions.

 Materials and Methods

Thirty-eight patients were enrolled in this study. All patients underwent an initial CT scan using 370 mgI/mL iodinated contrast media. Patients were then randomized into two groups for a followup CT. Group A (n = 19) received 250 mgI/mL iodinated contrast media, and group B (n = 19) received 300 mgI/mL contrast media. The mean Hounsfield units (HU values) of small renal lesions with a maximum size of less than 2 cm were calculated. Signal to noise ratios (SNR values) were likewise evaluated. Three uroradiologists assessed the lesion's conspicuity and the diagnostic influence of the artifact's proximity to the adjacent renal parenchyma.

 Results

In group A, there were significant differences between the HU values of renal lesions and those of the adjacent renal parenchyma between the initial and followup CT. Conversely, in group B, there was no significant difference. Moreover, SNR values showed no statistically significant difference between both groups. Regarding lesion conspicuity, only one reader identified a significant difference (p = 0.032) in group A; whereas in group B, there was no statistical difference. The artifact's proximity to the adjacent renal parenchyma did not appear to have any diagnostic influence on differ-entiating the two (p < 0.05).

 Conclusion

In evaluating small renal lesions, 300 mgI/mL instead of 370 mgI/mL contrast media can be used; however, it is important to note that the use of 250 mgI/ mL contrast media may reveal different results from that of 370 mgI/mL contrast media.

 Index terms Multidetector Computed Tomography Contrast Media Kidney Iodine Diagnostic Imaging REFERENCES Rengo M Caruso D De Cecco CN Lucchesi P Bellini D Ma-ceroni MM High concentration (400 mgI/mL) versus low concentration (320 mgI/mL) iodinated contrast media in multi detector computed tomography of the liver: a randomized, single centre, noninferiority study Eur J Radiol 20128130963101 Rengo M Bellini D De Cecco CN Osimani M Vecchietti F Caruso D The optimal contrast media policy in CT of the liver. Part II: clinical protocols Acta Radiol 201152 473480 Laghi A Multidetector CT (64 slices) of the liver: examination techniques Eur Radiol 200717675683 Marchianò A Spreafico C Lanocita R Frigerio L Di Tolla G Patelli G Does iodine concentration affect the diagnostic efficacy of biphasic spiral CT in patients with hepatocellular carcinoma? Abdom Imaging 200530274280 Kondo H Kanematsu M Goshima S Tomita Y Kim MJ Moriyama N Body size indexes for optimizing iodine dose for aortic and hepatic enhancement at multidetector CT: comparison of total body weight, lean body weight, and blood volume Radiology 2010254163169 Kondo H Kanematsu M Goshima S Watanabe H Onozuka M Moriyama N Aortic and hepatic enhancement at multidetector CT: evaluation of optimal iodine dose deter-mined by lean body weight Eur J Radiol 201180e273e277 Yanaga Y Awai K Nakaura T Namimoto T Oda S Funama Y Optimal contrast dose for depiction of hypervas-cular hepatocellular carcinoma at dynamic CT using 64-MDCT AJR Am J Roentgenol 200819010031009 Fleischmann D Multiple detector-row CT angiography of the renal and mesenteric vessels Eur J Radiol 200345 Suppl 1S79S87 Johnson PT Fishman EK IV contrast selection for MDCT: current thoughts and practice AJR Am J Roentgenol 2006186 406415 Loewe C Becker CR Berletti R Cametti CA Caudron J Cou-dyzer W 64-Slice CT angiography of the abdominal aorta and abdominal arteries: comparison of the diagnostic efficacy of iobitridol 350 mgI/mL versus iomeprol 400 mgI/mL in a prospective, randomised, double-blind multi-centre trial Eur Radiol 201020572583 Katzberg RW Barrett BJ Risk of iodinated contrast material–induced nephropathy with intravenous administration Radiology 2007243622628 Thomsen HS Morcos SK Barrett BJ Contrast-induced ne-phropathy: the wheel has turned 360 degrees Acta Radiol 200849646657 Nyman U Almén T Aspelin P Hellström M Kristiansson M Sterner G Contrast-medium-Induced nephropathy corre-lated to the ratio between dose in gram iodine and esti-mated GFR in mL/min Acta Radiol 200546830842 Lim A O'Neil B Heilbrun ME Dechet C Lowrance WT The contemporary role of renal mass biopsy in the management of small renal tumors Front Oncol 2012 2106 Lee CT Katz J Shi W Thaler HT Reuter VE Russo P Surgical management of renal tumors 4 cm. Or less in a contemporary cohort J Urol 2000163730736 Nguyen MM Gill IS Ellison LM The evolving presentation of renal carcinoma in the United States: trends from the surveillance, epidemiology, and end results program J Urol 20061766 Pt 123972400 discussion 2400 Alasker A Williams SK Ghavamian R Small renal mass: to treat or not to treat Curr Urol Rep 2013141318 Sandstede JJ Kaupert C Roth A Jenett M Harz C Hahn D Comparison of different iodine concentrations for multidetector row computed tomography angiography of segmen-tal renal arteries Eur Radiol 20051512111214 Sandstede JJ Werner A Kaupert C Roth A Jenett M Harz C A prospective study comparing different iodine concentrations for triphasic multidetector row CT of the upper abdomen Eur J Radiol 2006609599 Kaufman L Kramer DM Crooks LE Ortendahl DA Measur-ing signal-to-noise ratios in MR imaging Radiology 1989 173265267 Firbank MJ Coulthard A Harrison RM Williams ED A comparison of two methods for measuring the signal to noise ratio on MR images Phys Med Biol 199944N261N264 Magnotta VA Friedman L FIRST BIRN Measurement of signal-to-noise and contrast-to-noise in the fBIRN multicenter imaging study J Digit Imaging 200619140147 Setty BN Sahani DV Ouellette-Piazzo K Hahn PF Shepard JA Comparison of enhancement, image quality, cost, and adverse reactions using 2 different contrast medium concentrations for routine chest CT on 16-slice MDCT J Comput Assist Tomogr 200630818822 Holalkere NS Matthes K Kalva SP Brugge WR Sahani DV 64-slice multidetector row CT angiography of the abdomen: comparison of low versus high concentration iodinated contrast media in a porcine model Br J Radiol 2011 84221228 Kundel HL Polansky M Measurement of observer agree-ment Radiology 2003228303308 Bae KT Optimization of contrast enhancement in thoracic MDCT Radiol Clin North Am 201048929 Schoellnast H Brader P Oberdabernig B Pisail B Deut-schmann HA Fritz GA High-concentration contrast media in multiphasic abdominal multidetector-row computed tomography: effect of increased iodine flow rate on parenchymal and vascular enhancement J Comput Assist Tomogr 200529582587 Berland LL Lee JY Comparison of contrast media injection rates and volumes for hepatic dynamic incremented computed tomography Invest Radiol 198823918922 Chambers TP Baron RL Lush RM Hepatic CT enhancement. Part I. Alterations in the volume of contrast material within the same patients Radiology 1994193513517 Dean PB Violante MR Mahoney JA Hepatic CT contrast enhancement: effect of dose, duration of infusion, and time elapsed following infusion Invest Radiol 198015158161 Heiken JP Brink JA McClennan BL Sagel SS Crowe TM Gaines MV Dynamic incremental CT: effect of volume and concentration of contrast material and patient weight on hepatic enhancement Radiology 1995195353357 Heiken JP Brink JA McClennan BL Sagel SS Forman HP DiCroce J Dynamic contrast-enhanced CT of the liver: comparison of contrast medium injection rates and uniphasic and biphasic injection protocols Radiology 1993187327331 Ramgren B Björkman-Burtscher IM Holtås S Siemund R CT angiography of intracranial arterial vessels: impact of tube voltage and contrast media concentration on image quality Acta Radiol 201253929934 Bagrodia A Darwish OM Rapoport Y Margulis V Risk pre-diction in the management of small renal masses Curr Opin Urol 201222347352 Gill IS Aron M Gervais DA Jewett MA Clinical practice. Small renal mass N Engl J Med 2010362624634 Volpe A Panzarella T Rendon RA Haider MA Kondylis FI Jewett MA The natural history of incidentally detected small renal masses Cancer 2004100738745 Figures and Tables

Flow chart demonstrating the included patients. 38 patients underwent CT examination after injection of 370 mgI/mL contrast media. Subsequently, for the followup CT, the patients were randomized into two groups. Group A (n = 19) underwent their followup CT after injection of 250 mgI/mL contrast media, and group B (n = 19) underwent CT examination after injection of 300 mgI/mL contrast media.

Small renal lesion of a 54-year-old male patient; imaged using 370 mgI/mL (A) and 250 mgI/mL contrast medium (B). A. The HU of the small renal lesion, imaged with 370 mgI/mL of contrast medium, was 50. B. The HU of the same lesion, imaged with 250 mgI/mL of contrast medium, was 18.1. There was a significant difference in the HUs of the small renal lesions in group A. HU = Hounsfield unit

A small renal lesion of a 41-year-old male patient; imaged using 370 mgI/mL (A) and 300 mgI/mL of contrast medium (B). A. The HU of the small renal lesion, imaged with 370 mgI/mL of contrast medium, was 5.0. B. The HU of the same lesion, imaged with 300 mgI/mL of contrast medium, was 7.0. There was no significant difference in the HUs of the small renal lesions in group B. HU = Hounsfield unit

Mean and SD of Each Small Renal Lesions and Surrounding Tissues

Contrast Medium Group A (n = 30) Group B (n = 13)
370 mgI/mL 250 mgI/mL 370 mgI/mL 300 mgI/mL
Renal lesion HU        
 Mean 44.9 32.3 32.6 31.8
 SD 26.0 24.4 28.6 28.1
 p-value 0.002   0.552  
Surrounding parenchyma HU        
 Mean 197.6 160.5 190.6 187.8
 SD 29.9 24.8 34.2 28.6
 p-value < 0.001   0.279  
Signal to noise        
 Mean 34.4 29.0 26.6 32.1
 SD 16.6 15.3 12.0 20.4
 p-value 0.144   0.382  

HU = Hounsfield unit, SD = standard deviation

Qualitative Evaluation of Lesion Conspicuity in Both Groups

  Group A (n = 30) (370 mgI/mL vs. 250 mgI/mL) Group B (n = 13) (370 mgI/mL vs. 300 mgI/mL)
Lesion Conspicuity p-Value Average Weighted Kappa (370 mgI/mL)∗ Average Weighted Kappa (250 mgI/mL)∗ p-Value Average Weighted Kappa (370 mgI/mL)∗ Average Weighted Kappa ICC (300 mgI/mL)∗
Reader 1 0.573 0.362 0.345 0.132 0.333 0.495
Reader 2 0.224     0.086    
Reader 3 0.032     0.380    

Average weighted kappa: average weighted kappa value for reader 1 versus 2, reader 2 versus 3, and reader 1 versus 3.

Influence of the Artifact to Adjacent Parenchyma

  Group A (n = 19) (370 mgI/mL vs. 250 mgI/mL) Group B (n = 19) (370 mgI/mL vs. 300 mgI/mL)
370 mgI/mL 250 mgI/mL p-Value 370 mgI/mL 300 mgI/mL p-Value
Yes No Yes No Yes No Yes No
Reader 1 0 19 0 19 1.000 2 17 4 15 0.301
Reader 2 0 19 1 18 0.317 0 19 0 19 1.000
Reader 3 1 18 0 19 0.317 1 18 1 18 1.000
Proportion of agreements (%) 94.7 94.7   89.5 78.9