Diffusion-weighted MRI improves response assessment after definitive radiotherapy in patients with NSCLC

Abstract

Background Computed tomography (CT) is the standard procedure for follow-up of non-small-cell lung cancer (NSCLC) after radiochemotherapy. CT has difficulties differentiating between tumor, atelectasis and radiation induced lung toxicity (RILT). Diffusion-weighted imaging (DWI) may enable a more accurate detection of vital tumor tissue. The aim of this study was to determine the diagnostic value of MRI versus CT in the follow-up of NSCLC. Methods Twelve patients with NSCLC stages I-III scheduled for radiochemotherapy were enrolled in this prospective study. CT with i.v. contrast agent and non enhanced MRI were performed before and 3, 6 and 12 months after treatment. Standardized ROIs were used to determine the apparent diffusion weighted coefficient (ADC) within the tumor. Tumor size was assessed by the longest longitudinal diameter (LD) and tumor volume on DWI and CT. RILT was assessed on a 4-point-score in breath-triggered T2-TSE and CT. Results There was no significant difference regarding LD and tumor volume between MRI and CT (p ≥ 0.6221, respectively p ≥ 0.25). Evaluation of RILT showed a very high correlation between MRI and CT at 3 (r = 0.8750) and 12 months (r = 0.903). Assessment of the ADC values suggested that patients with a good tumor response have higher ADC values than non-responders. Conclusions DWI is equivalent to CT for tumor volume determination in patients with NSCLC during follow up. The extent of RILT can be reliably determined by MRI. DWI could become a beneficial method to assess tumor response more accurately. ADC values may be useful as a prognostic marker.

MR-guided radiotherapy in node-positive non-small cell lung cancer and severely limited pulmonary reserve: a report proposing a new clinical pathway for the management of high-risk patients

“…Importantly, online MRgRT enables real-time tumour monitoring during treatment and motion management by means of gating/tracking strategies thus eliminating the need for larger margins or internal target volume (ITV) concepts to account for tumour mobility. To further unlock new capabilities of this novel technology, functional imaging including diffusion-weighted imaging facilitates response assessment during and after primary treatment [ 12 ]. Therefore, promoting adaptive and dose-escalation strategies based on biological response similar to concepts employed with PET imaging [ 13 , 14 ].…”

Elaboration of Multiparametric MRI‐Based Radiomics Signature for the Preoperative Quantitative Identification of the Histological Grade in Patients With Non‐Small‐Cell Lung Cancer

“…22 The continuous technical development in MRI with fast imaging techniques, resulting in protocols with scan times between 15 and 30 minutes, 23 has made chest MRI an interesting alternative to CT. 19,24 In addition, MRI can provide additional functional sequences compared to CT, especially DWI. From the latest research, tumor volume measurement can be done by DWI yielding similar results to CT. 25 Only a few studies have explored the preoperative differentiation of NSCLC histological grades based on dual-energy CT and ADC in recent years. 9,26 These tests have limitations, including CT ionizing radiation problems and overlap of ADC values.…”

“…In addition, MRI can provide additional functional sequences compared to CT, especially DWI. From the latest research, tumor volume measurement can be done by DWI yielding similar results to CT 25 . Only a few studies have explored the preoperative differentiation of NSCLC histological grades based on dual‐energy CT and ADC in recent years 9,26 .…”

CT Combined with Multiparameter MRI in Differentiating Pathological Subtypes of Non‐Small‐Cell Lung Cancer before Surgery

“…Besides, a very small number of patients cannot complete an MRI examination due to claustrophobic syndrome or ferromagnetic objects in the body that cannot be removed. At present, it has been stated that DW-MRI plays an equivalent role to CT in detecting tumor volume in NSCLC patients after chemotherapy and can even reliably determine the range of radiation-induced lung toxicity [ 26 ]. Gkogkozotou et al [ 22 ] have found that the combination of PET/CT and brain MRI is beneficial to accurately classifying the stages of NSCLC and reduce avoidable thoracotomy.…”