Meta-analysis of diffusion-weighted imaging for predicting locoregional failure of chemoradiotherapy in patients with head and neck squamous cell carcinoma

Integration of quantitative imaging biomarkers in clinical trials for MR-guided radiotherapy: Conceptual guidance for multicentre studies from the MR-Linac Consortium Imaging Biomarker Working Group

Quantitative imaging biomarkers (QIBs) derived from MRI techniques have the potential to be used for the personalised treatment of cancer patients. However, large-scale data are missing to validate their added value in clinical practice. Integrated MRI-guided radiotherapy (MRIgRT) systems, such as hybrid MRI-linear accelerators, have the unique advantage that MR images can be acquired during every treatment session. This means that high-frequency imaging of QIBs becomes feasible with reduced patient burden, logistical challenges, and costs compared to extra scan sessions. A wealth of valuable data will be collected before and during treatment, creating new opportunities to advance QIB research at large. The aim of this paper is to present a roadmap towards the clinical use of QIBs on MRIgRT systems. The most important need is to gather and understand how the QIBs collected during MRIgRT correlate with clinical outcomes. As the integrated MRI scanner differs from traditional MRI scanners, technical validation is an important aspect of this roadmap. We propose to integrate technical validation with clinical trials by the addition of a quality assurance procedure at the start of a trial, the acquisition of in vivo test-retest data to assess the repeatability, as well as a comparison between QIBs from MRIgRT systems and diagnostic MRI systems to assess the reproducibility. These data can be collected with limited extra time for the patient. With integration of technical validation in clinical trials, the results of these trials derived on MRIgRT systems will also be applicable for measurements on other MRI systems.

MRI Posttreatment Surveillance for Head and Neck Squamous Cell Carcinoma: Proposed MR NI-RADS Criteria

BACKGROUND AND PURPOSE

The current Neck Imaging Reporting and Data System (NI-RADS) criteria were designed for contrast-enhanced CT with or without PET. Prior studies have revealed the capability of DWI and T2 signal intensity in distinguishing locoregional tumor residual and recurrence from posttreatment benign findings in head and neck cancers. We aimed to propose MR imaging NI-RADS criteria by adding diffusion criteria and T2 signal intensity to the American College of Radiology NI-RADS template.

MATERIALS AND METHODS

This retrospective study included 69 patients with head and neck squamous cell carcinoma (HNSCC) who underwent posttreatment contrast-enhanced MRI imaging surveillance using a 1.5T scanner. The scans were interpreted by 2 neuroradiologists. Image analysis assessed the primary tumor site using the current American College of Radiology NI-RADS morphologic lexicon (mainly designed for contrast-enhanced CT with or without PET). NI-RADS rescoring was then performed based on our proposed criteria using T2 signal and diffusion features. The reference standard was a defined set of criteria, including clinical and imaging follow-up and pathologic assessment.

RESULTS

Imaging assessment of treated HNSCC at the primary tumor site using T2 signal intensity and diffusion features as modifying rules to NI-RADS showed higher sensitivity, specificity, positive predictive value, negative predictive value, and accuracy (92.3%, 90.7%, 85.7%, 95.1%, and 91.3%, respectively) compared with the current NI-RADS lexicon alone (84.6%, 81.4%, 73.3%, 89.8%, and 82.6%, respectively).

CONCLUSIONS

The addition of diffusion features and T2 signal to the American College of Radiology NI-RADS criteria for the primary tumor site enhances the specificity, sensitivity, positive predictive value, negative predictive value, and NI-RADS accuracy.

Impact of a dedicated radiologist as a member of the head and neck tumour board: a single-institution experience

The aim of this study was to quantify the impact of radiologic image review performed by experienced radiologists in a multidisciplinary team (MDT) for head and neck cancers (HNCs). We performed a retrospective review of cases discussed at MDT meetings from April 2014 to March 2017 for which radiologic review was required. All changes in the former radiologic report were collected and classified as follows: 1) modifications of radiological reports (patients for whom the treatment strategy had not been defined at the moment of MDT meeting) and 2) modifications in treatment strategy (patients for whom treatment strategy had previously been defined and subsequently modified according to the outcome of radiologic revision). The latter subgroup was further categorised as “major changes” and as “minor changes”. A total of 540 cases were retrieved. Imaging review was required at the time of tumour diagnosis in 310 (57.4%) cases. Most patients (69%) had advanced stage tumours (III and IV). In 262 (48%) cases, no change of the initial radiologic report was made. In a total of 144 (27%) cases, the available imaging was not considered sufficient for a final indication to treatment and further imaging was required. In the remaining 134 (25%) cases, radiologic review led to a modification of either tumour staging (55%) or treatment strategy (45%). Specifically, major and minor modifications were applied in 44 (13%) and 17 (11%) of the cases considered, respectively. Among 134 patients for whom the radiologic review led to stage/treatment modification, follow-up was available for 118. In all but one patient, we could confirm the original reports were correctly modified per MDT discussion results. Our data strongly support the importance of including an experienced radiologist as a core member of the MDT for HNCs.