An Interactive Teaching Website for Tc-99m MAG3 Diuretic Renography (https://MAG3renography.net)

Introduction: The majority of the estimated 590,000 radionuclide renal scans performed annually in the United States are conducted at sites that perform fewer than 3 studies per week. Due to the relative infrequency of renal studies, some trainees may fail to acquire the expertise needed for a competent interpretation, a problem shared by radiologists whose nuclear medicine training was limited to 3-4 months. Limited training and experience may lead to incorrect scan interpretation, discourage use of the procedure, and negatively impact patient care.

To address this problem, we developed software (RENEX) to assist in the interpretation of Tc-99m MAG3 diuretic renal scans [1-3]. RENEX is a heuristic or rule based decision support system that uses quantitative data derived from the renogram to determine the status of a potentially obstructed kidney (obstructed, indeterminate, or not obstructed). RENEX provides the justification (rules) for its interpretation and specifies a level of confidence [1,4].

RENEX has a diagnostic accuracy comprable to that of experts and greater diagnostic accuracy than that of nuclear medicine residents with one year of training; the diagnostic accuracy of these experienced residents improved when they reinterpreted the cases with access to RENEX [5]. RENEX also outperformed a second set of experienced nuclear medicine residents and diagnostic accuracy again improved with access to RENEX [6]. Following exposure to RENEX, these residents interpreted a new set of cases and had better agreement with experts than that obtained on the initial set [6].

Methods: We designed a website to supplement resident and physician exposure to Tc-99m MAG3 diuretic studies and make the teaching components of RENEX more broadly available.

Results: The website is organized into a Home Page, Introduction Pages, a Case Review Page, RENEX and Expert Interpretation Pages. The Introduction Pages provide a sample study accompanied by an explanation of relevant renogram parameters, links to references and a description of RENEX. The user scores each kidney on the Case Review Page as obstructed, indeterminate, or not obstructed using a numerical scoring system. The RENEX Interpretation (score) and justification becomes available to the user after the kidneys in the assigned cases have been scored. After reviewing the scores and justification by RENEX, users are asked to re- score each kidney. They may re-enter their original scores or modify their initial scores based on input from RENEX. Once the cases re-scored, the user is given access to the scores and comments of 3 experienced readers

Conclusions: This interactive web based format allows users to gain additional experience and supplement their diagnostic acumen by comparing their interpretations with the interpretations and rationale provided by RENEX and experts.

Garcia EV, et al. RENEX: An expert system for the interpretation of 99m Tc- MAG3 scans to detect renal obstruction. J Nucl Med 2006; 47:320 Taylor A, et al. Diagnostic performance of an expert system for interpretation of Tc-99m MAG3 scans in suspected obstruction. J Nucl Med 2008; 49:216 Taylor AT, Garcia EV. Computer-assisted diagnosis in renal nuclear medicine: Rationale, methodology and interpretative criteria for diuretic renography. Semin Nucl Med 2014;44:146 Garcia EV, et al. A software engine to justify the conclusions of an expert system for detecting renal obstruction on Tc-99m MAG3 scans. J Nucl Med 2007; 48:463 Taylor AT, et al: Tc-99m MAG3 diuretic renography: Impact of a decision support system (iRENEX) on resident interpretations. (abstract) J Nucl Med 2013, 54:171P. Taylor A, et al. Can RENEX teach residents better diagnostic skills? (abstract) J Nucl Med. 2016: 57:540.

Acknowldegements: This work was supported by grants from the US National Institute of Biomedical Imaging and Bioengineering, and the National Institute of Diabetes and Digestive and Kidney Diseases, R01EB008838 and RO1DK108070-01A1.