Kanako Kunishima Kumamaru MD, PhD, Presenter: Nothing to Disclose

Elizabeth George MD, Abstract Co-Author: Nothing to Disclose

Ayaz Aghayev MD, Abstract Co-Author: Nothing to Disclose

Sachin Shyamsunder Saboo FRCR, MD, Abstract Co-Author: Nothing to Disclose

Ashish Rajendra Khandelwal MD, Abstract Co-Author: Nothing to Disclose

Frank John Rybicki MD, PhD, Abstract Co-Author: Research Grant, Toshiba Corporation

German Gonzalez PhD, Abstract Co-Author: Nothing to Disclose

Daniel Jimenez-Carretero MSc, Abstract Co-Author: Nothing to Disclose

Maria J. Ledesma-Carbayo PhD, Abstract Co-Author: Nothing to Disclose

Sara Rodriguez-Lopez, Abstract Co-Author: Nothing to Disclose

Raul San Jose Estepar PhD, Abstract Co-Author: Nothing to Disclose

Tianrun Cai MD, Abstract Co-Author: Nothing to Disclose

Amir Imanzadeh MD, Abstract Co-Author: Nothing to Disclose

Rani S. Sewatkar MBBS, Abstract Co-Author: Nothing to Disclose

Zoha Hussain, Abstract Co-Author: Nothing to Disclose

The CT-derived right to left ventricular (RV/LV) diameter ratio predicts prognosis in patients with acute pulmonary embolism (PE). We developed and retrospectively demonstrated that a new software package to automatically calculate the RV/LV diameter ratio on axial CT Pulmonary Angiography (CTPA) images has high prognostic value. The purpose of this study was to prospectively test the performance and usability of the software using reference standard manual clinical measurements.

This HIPAA-compliant IRB-approved study prospectively included 115 CTPA studies positive for acute PE. Each study underwent 4 measurements: 1) completely automated RV/LV diameter ratio from the software; 2 & 3) semi-automatic calculation via manual adjustment of the automated measurement by two reads from blinded, independent radiologists; 4) manually RV/LV diameter measurement. The radiologists in measurements 2 & 3 documented reasons for adjustment of software output data. The time was recorded for all measurements. Correlation and Bland-Altman plots were used to compare the different measurement techniques.

At least one radiologist considered manual adjustment necessary for all 115 automated RV/LV measurements for the following reasons: detection of wrong chamber (5.2%), ventricular edge adjustment (82.6%), wrong diameter orientation (71.3%) or the wrong orientation of the caliper (24.3%). The mean difference in the RV/LV diameter ratio between manual and automatic measurement was 0.067 (1.09±.25 vs.1.03±.35), and was improved by manual adjustments (0.045 and 0.022). Adjustments by the radiologists also improved the correlation with the manual measurements (Pearson’s r= from 0.675 to 0.872 and 0.887). The mean time required for manual adjustment of the fully automated data (37±20 seconds) was significantly (p<0.001) shorter than the time for the complete manual measurements (100±23 seconds). 

Manual adjustments of the automatically generated CT-derived RV/LV diameter ratios in patients with acute PE produced reliable values with a 64% reduction in the time required for calculation when compared to clinical manual measurements. 

Previously validated software that automatically calculates the CT- RV/LV diameter ratio enables accurate measurements for clinical reporting after an average input of 37 seconds by the radiologist.

Kumamaru, K, George, E, Aghayev, A, Saboo, S, Khandelwal, A, Rybicki, F, Gonzalez, G, Jimenez-Carretero, D, Ledesma-Carbayo, M, Rodriguez-Lopez, S, San Jose Estepar, R, Cai, T, Imanzadeh, A, Sewatkar, R, Hussain, Z, Prospective Evaluation of Automated Ventricular Diameter Ratio Computation Software for Positive CT Pulmonary Angiography.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14002677.html