Use of Multiphase CT Protocols in 18 Countries: Appropriateness and Radiation Doses

Abstract

Purpose: To assess the frequency, appropriateness, and radiation doses associated with multiphase computed tomography (CT) protocols for routine chest and abdomen–pelvis examinations in 18 countries. Materials and Methods: In collaboration with the International Atomic Energy Agency, multi-institutional data on clinical indications, number of scan phases, scan parameters, and radiation dose descriptors (CT dose–index volume; dose–length product [DLP]) were collected for routine chest (n = 1706 patients) and abdomen–pelvis (n = 426 patients) CT from 18 institutions in Asia, Africa, and Europe. Two radiologists scored the need for each phase based on clinical indications (1 = not indicated, 2 = probably indicated, 3 = indicated). We surveyed 11 institutions for their practice regarding single-phase and multiphase CT examinations. Data were analyzed with the Student t test. Results: Most institutions use multiphase protocols for routine chest (10/18 institutions) and routine abdomen–pelvis (10/11 institutions that supplied data for abdomen–pelvis) CT examinations. Most institutions (10/11) do not modify scan parameters between different scan phases. Respective total DLP for 1-, 2-, and 3-phase routine chest CT was 272, 518, and 820 mGy·cm, respectively. Corresponding values for 1- to 5-phase routine abdomen–pelvis CT were 400, 726, 1218, 1214, and 1458 mGy cm, respectively. For multiphase CT protocols, there were no differences in scan parameters and radiation doses between different phases for either chest or abdomen–pelvis CT ( P = 0.40-0.99). Multiphase CT examinations were unnecessary in 100% of routine chest CT and in 63% of routine abdomen–pelvis CT examinations. Conclusions: Multiphase scan protocols for the routine chest and abdomen–pelvis CT examinations are unnecessary, and their use increases radiation dose.

Managing Radiation Dose from Chest CT in Patients with COVID-19

“…It must be noted that multi-phase CT examinations, especially in routine chest CT, are reported to be unnecessary for most clinical indications. From the study of data on clinical indications recorded for multi-phase CT collected for 1706 patients from 11 institutions in 18 countries, other authors found that 100% of routine chest CT and 63% of routine abdomen-pelvis CT examinations were unnecessary ( 2 ). Karla et al noted that most publications on chest CT in COVID-19 pneumonia without complication report a single-phase, non-contrast chest CT and there is little use of contrast CT images from multi-phase scans because the clinical findings in COVID-19 pneumonia are mostly restricted to lungs ( 3 ).…”

Artificial intelligence in image reconstruction: The change is here

“…Even with the same clinical indication, large body habitus, or longer scan length of a clinically indicated body region can increase radiation dose. Another factor linked to clinical indications is imaging with multiple scan phases or for lesions that require better spatial resolution, both of which can compromise the extent to which radiation dose can be reduced [9,[29][30][31][32].…”

Higher patient doses through X-ray imaging procedures

“…Per exam, dose in CT has varied from about a mSv to about 15 mSv. Recent studies have shown that with the use of multiphase CT imaging and recurrent imaging, much higher doses are being received by some patients [11,12], as discussed later. Also, the use of CT for performing interventions has led to as much as 100 mSv in a single procedure [13].…”