Diagnostic and Interventional Radiology
Abdominal Imaging - Original Article

Multi-parametric MRI of rectal cancer – repeatability of quantitative data: a feasibility study

1.

Department of Radiology, Koç University School of Medicine, İstanbul, Turkey

2.

Department of General Surgery, Koç University School of Medicine, İstanbul, Turkey

Diagn Interv Radiol 2020; 1: -
Read: 342 Published: 24 October 2019

PURPOSE: In this study we aimed to analyze the repeatibility of quantitative multiparametric rectal MRI parameters with different measurement techniques.

METHODS: All the magnetic resonance imaging (MRI) examinations were performed with 3 Tesla MRI system. In addition to routine sequences for rectal cancer imaging protocol, small FOV DWI and perfusion sequences were acquired in each patient. ADC is used for diffusion analysis and ktrans is used for perfusion analysis. These parameters were measured by three different methods twice by one radiologist for intraobserver, and seperately by three radiologists for interobserver variability analysis. ADC was measured by three different techniques; the lowest value, the value where there is maximum wall thickness and with free hand technique. Ktrans was measured by three different techniques, at the slice where there is maximum wall thickness, with free hand ROI and at the dark red spot with maximum value.

RESULTS: A total of 30 patients, with biopsy proven rectal adenocarcinoma were included in the study. The mean value of the lowest ADC was measured as 721.31±147.18 mm2/s and 718.96±135.71 mm2/s by the first radiologist. The mean value of the ADC measured on the slice with maximum wall thickness was measured as 829.90±144.24 mm2/s and 829.48±149.23 mm2/s by the first observer. The mean of the ADC value measured by free hand ROI on the slice where there is maximum wall thickness was 846.56±136.31 mm2/s for the first and 848.23±144.15 mm2/s for the second measurement. The mean of the ktrans value on the slice with maximum wall thickness was measured as 0.219±0.080 and 0.214±0.074 by the first radiologist. The mean of the ktrans measured by free hand ROI technique (including as much tumoral tissue as possible) was 0.208±0.074 and 0.207±0.069, by the first observer. The mean of the ktrans measured from the dark red foci was 0.308±0.109 as the first measurement and 0.311±0.105 as the second measurement by the first observer. Intraobserver agreement was very good among diffusion and perfusion parameters obtained with three different measurement techniques.

Interobserver agreement was very good, except one of the measurement techniques. As far as interobserver variability is considered, only one of the parameters differed significantly. That parameter was the ADC value measured on the slice with maximum wall thickness.

CONCLUSION: Multiparametric MRI of rectum, using ADC as the diffusion and ktrans as the perfusion parameter is a repeatable technique. This technique may have the potential in prediction and evaluation of neoadjuvant treatment response. New studies with larger patient groups are needed to validate the role of multiparametric MRI.

EISSN 1305-3612