Role of diffusion-weighted MRI in diagnosis and post therapeutic follow-up of colorectal cancer

Abstract

Background The colorectal cancer (CRC) is one of the deadliest cancers in the world. Local tumor stage, vascular or lymphatic invasion, and tumor grade are essential for accurate management. The main imaging modality for initial assessment and therapeutic response evaluation of CRC is magnetic resonance imaging (MRI). The purpose of this prospective study was to illustrate the role of diffusion-weighted MRI (DWI) and apparent diffusion coefficient (ADC) value in initial assessment and grading of colorectal carcinoma as well as evaluation of its response to chemotherapy or combined chemoradiation. Results Restricted diffusion in DWI was found in 37 out of 40 patients with sensitivity of about 92.5%. In the studied group, the median ADC value was 1.21 (min 0.80, max 1.31) and the average ADC value was 1.14 ± 0.161. The mean ADC value in poorly differentiated tumors was 0.979 × 10−3mm2/s. The mean ADC value in moderately differentiated tumors was 1.112 × 10−3mm2/s. The mean ADC value in well-differentiated tumors was 1.273 × 10−3mm2/s. The sensitivity, specificity, PPV, NPV, and accuracy were higher with addition of DWI and ADC value to conventional MRI reaching 100%, 80%, 83.3%, 100%, and 90%, respectively. Conclusion Adding DW imaging with ADC value to conventional MRI yields better diagnostic accuracy than using conventional MR imaging alone in detection, correlation with tumor histologic grade, initial staging, and response evaluation to neoadjuvant chemoradiotherapy in patients with locally advanced colorectal cancer.

Diffusion-Weighted MRI as a Quantitative Imaging Biomarker in Colon Tumors

“…This is in agreement with a study on rectal polyps [21]. Other rectal MRI studies have shown similar results [15,22,23], but the literature is scarce on colonic tumors. We found…”

“…This is in agreement with a study on rectal polyps [21]. Other rectal MRI studies have shown similar results [15,22,23], but the literature is scarce on colonic tumors. We found no statistical difference in mADC values between N0 and N+ groups, and pT1-pT2 and pT3-pT4 groups.…”

“…In rectal cancer, DWI is used in follow-up to differentiate between scar tissue and residual cancer tissue after neoadjuvant therapy [ 14 , 15 , 16 , 17 ]. DWI is currently recommended by the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) to be used only qualitatively and not quantitatively, because of a lack of standardization between different MRI systems and imaging protocols [ 5 ].…”

Magnetic Fields and Cancer: Epidemiology, Cellular Biology, and Theranostics

“…Pelvic MRI is used for the local of T and N staging of rectal cancer and has the advantage of improved patient comfort [542], improved reproducibility and accuracy [543], reduced care costs [544], and for completeness and better understanding of related pelvic anatomy [545][546][547]. The use of DWI with ADC value in addition to conventional MRI yields better diagnostic accuracy than using conventional MRI alone in detection, correlation with tumor histologic grade, and the initial staging in patients with locally advanced colorectal cancer [548,549]; however, DW-MRI is inferior to [F-18]-FDG-PET for the detection of primary lesions but superior for the detection of lymph node metastases [550]. MRI shows moderate sensitivity and good specificity for the detection of extramural venous invasion (EMVI) in colorectal cancer [551,552], while 3D colorectal MRI gives better and accurate segmentation results than 3D fully convolutional neural networks alone [553].…”