Improvement in male pelvis magnetic resonance image contouring following radiologist-delivered training.

INTRODUCTION: The magnetic resonance linear accelerator (MRL) combines both magnetic resonance imaging and a linear accelerator, allowing for daily treatment adaptation. This study aimed to assess the impact of radiologist-delivered training in magnetic resonance (MR) contouring of relevant structures within the male pelvis. METHODS: Two radiation oncologists, two radiation oncology registrars and seven radiation therapists completed contouring on 10 male pelvis MR datasets both pre- and post-training. A 2-hour MR anatomy training session was delivered by a radiologist, who also provided the 'gold standard' contours. The pre- and post-training contours were compared against the gold standard with Dice similarity coefficient (DSC) and Hausdorff distances calculated; and the pre- and post-confidence scores and timing were compared. RESULTS: The improvement in DSC were significant in prostate, rectum and seminal vesicles, with a post-training median DSC of 0.87 ± 0.06, 0.92 ± 0.04 and 0.80 ± 0.14, respectively. The median Hausdorff improved with a median of 1.46 ± 0.78 mm, 0.52 ± 0.32 mm and 1.11 ± 0.86 mm for prostate, rectum and seminal vesicles, respectively. Bladder concordance was high both pre- and post-training. Urethra contours improved post-training, however, remained difficult to contour with a median post-DSC of 0.51 ± 0.24. Overall, confidence scoring improved (P < 0.001) and timing decreased by an average of 4.4 ± 16.4 min post-training. CONCLUSION: Radiologist-delivered training improved concordance of male pelvis contouring on MR datasets. Further work is required in the identification of urethra on MRs. These findings are of importance in the MRL adaptive workflow.

Delineation uncertainties of tumour volumes on MRI of head and neck cancer patients.

Background: During the last decade, radiotherapy using MR Linac has gone from research to clinical implementation for different cancer locations. For head and neck cancer (HNC), target delineation based only on MR images is not yet standard, and the utilisation of MRI instead of PET/CT in radiotherapy planning is not well established. We aimed to analyse the inter-observer variation (IOV) in delineating GTV (gross tumour volume) on MR images only for patients with HNC. Material/methods: 32 HNC patients from two independent departments were included. Four clinical oncologists from Denmark and four radiation oncologists from Australia had independently contoured primary tumour GTVs (GTV-T) and nodal GTVs (GTV-N) on T2-weighted MR images obtained at the time of treatment planning. Observers were provided with sets of images, delineation guidelines and patient synopsis. Simultaneous truth and performance level estimation (STAPLE) reference volumes were generated for each structure using all observer contours. The IOV was assessed using the DICE Similarity Coefficient (DSC) and mean absolute surface distance (MASD). Results: 32 GTV-Ts and 68 GTV-Ns were contoured per observer. The median MASD for GTV-Ts and GTV-Ns across all patients was 0.17 cm (range 0.08-0.39 cm) and 0.07 cm (range 0.04-0.33 cm), respectively. Median DSC relative to a STAPLE volume for GTV-Ts and GTV-Ns across all patients were 0.73 and 0.76, respectively. A significant correlation was seen between median DSCs and median volumes of GTV-Ts (Spearman correlation coefficient 0.76, p < 0.001) and of GTV-Ns (Spearman correlation coefficient 0.55, p < 0.001). Conclusion: Contouring GTVs in patients with HNC on MRI showed that the median IOV for GTV-T and GTV-N was below 2 mm, based on observes from two separate radiation departments. However, there are still specific regions in tumours that are difficult to resolve as either malignant tissue or oedema that potentially could be improved by further training in MR-only delineation.

Evaluating diffusion-weighted magnetic resonance imaging for target volume delineation in head and neck radiotherapy.

INTRODUCTION: Inter-observer variability (IOV) in target volume delineation is a source of error in head and neck radiotherapy. Diffusion-weighted imaging (DWI) has been shown to be useful in detecting recurrent head and neck cancer. This study aims to determine whether DWI improves target volume delineation and IOV. METHODS: Four radiation oncologists delineated the gross tumour volume (GTV) for ten head and neck cancer patients. Delineation was performed on CT alone as well as fused image sets which incorporated fluorodeoxyglucose (FDG)-positron emission tomography (PET) and magnetic resonance imaging (MRI) in the form of CT/PET, CT/PET/T2W and CT/PET/T2W/DWI image sets. Analysis of the variability of contour volumes was completed by comparison to the simultaneous truth and performance level estimation (STAPLE) volumes. The DICE Similarity Coefficient (DSC) and other IOV metrics for each observer's contour were compared to the STAPLE for each patient and image dataset. A DWI usability scoresheet for delineation was completed. RESULTS: The CT/PET/T2W/DWI mean GTV volume of 13.37 (10.35-16.39)cm3 was shown to be different to the mean GTV of 10.92 (8.32-13.51)cm3 when using CT alone (P < 0.001). The GTV DSC amongst observers for CT alone was 0.72 (0.65-0.79), CT/PET was 0.73 (0.67-0.80), CT/PET/T2W was 0.71 (0.64-0.77) and CT/PET/T2W/DWI was 0.69 (0.61-0.75). CONCLUSION: Mean GTVs with the addition of DWI had slightly larger volumes compared to standard CT and CT/PET volumes. DWI may add supplemental visual information for GTV delineation while having a small impact on IOV, therefore potentially improving target volume delineation.

Multiparametric magnetic resonance imaging in mucosal primary head and neck cancer: a prospective imaging biomarker study.

BACKGROUND: Radical radiotherapy, with or without concomitant chemotherapy forms the mainstay of organ preservation approaches in mucosal primary head and neck cancer. Despite technical advances in cancer imaging and radiotherapy administration, a significant proportion of patients fail to achieve a complete response to treatment. For those patients who do achieve a complete response, acute and late toxicities remain a cause of morbidity. A critical need therefore exists for imaging biomarkers which are capable of informing patient selection for both treatment intensification and de-escalation strategies. METHODS/DESIGN: A prospective imaging study has been initiated, aiming to recruit patients undergoing radical radiotherapy (RT) or chemoradiotherapy (CRT) for mucosal primary head and neck cancer (MPHNC). Eligible patients are imaged using FDG-PET/CT before treatment, at the end of week 3 of treatment and 12 weeks after treatment completion according to local imaging policy. Functional MRI using diffusion weighted (DWI), blood oxygen level-dependent (BOLD) and dynamic contrast enhanced (DCE) sequences is carried out prior to, during and following treatment. Information regarding treatment outcomes will be collected, as well as physician-scored and patient-reported toxicity. DISCUSSION: The primary objective is to determine the correlation of functional MRI sequences with tumour response as determined by FDG-PET/CT and clinical findings at 12 weeks post-treatment and with local control at 12 months post-treatment. Secondary objectives include prospective correlation of functional MRI and PET imaging with disease-free survival and overall survival, defining the optimal time points for functional MRI assessment of treatment response, and determining the sensitivity and specificity of functional MRI sequences for assessment of potential residual disease following treatment. If the study is able to successfully characterise tumours based on their functional MRI scan characteristics, this would pave the way for further studies refining treatment approaches based on prognostic and predictive imaging data. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12616000534482 (26 April 2016).

Intensity-modulated radiotherapy in the treatment of locoregionally advanced head and neck cancer: implementation and outcomes in a New Zealand community hospital.

INTRODUCTION: Intensity-modulated radiotherapy (IMRT) has become the standard of care for squamous cell cancer of the head and neck (HNSCC). This report presents early outcomes of IMRT with concomitant chemotherapy in a community setting in New Zealand. METHODS: Forty-eight patients with stage III and IV advanced HNSCC received definitive treatment with IMRT. A dose of 66 Gy in 30 fractions was delivered over 6 weeks with 3-weekly concurrent cisplatin after a single induction cycle of cisplatin and 5-fluorouracil. Acute toxicity, locoregional control (LRC), disease-free survival and overall survival (OS) outcomes were analysed. RESULTS: Follow-up ranged from 2 to 82 months (median 34 months). Acute grade 2 toxicity was observed in 27 patients and grade 3 toxicity in 19 patients. No patients experienced grade 4 toxicity and there were no treatment-related deaths. Locoregional failures occurred in six patients and distant metastatic disease occurred in five patients. Actuarial estimates of 3-year LRC, disease-free survival and OS were 87.3%, 74.4% and 73.7% respectively. CONCLUSION: Definitive treatment of stage III and IV cancer of the head and neck with IMRT and concurrent chemotherapy was achievable in the community setting. Acute toxicities were manageable and 3-year outcomes were comparable to other published series.

The association between homocysteine and myocardial infarction is independent of age, sex, blood pressure, cholesterol, smoking and markers of inflammation: the Glasgow Myocardial Infarction Study.

UNLABELLED: Homocysteine is associated with both myocardial infarction and arterial wall inflammation. To establish whether homocysteine is associated with myocardial infarction after adjusting for age, sex, the major cardiovascular risk factors and inflammatory risk predictors (fibrinogen, C-reactive protein and interleukin-6). A case-control study, using 364 myocardial infarction cases drawn from the north Glasgow MONICA study, 3-9 months after their event, and 383 controls drawn from the general population of the same geographical area. The odds ratio for myocardial infarction increased progressively across the four quarters of the homocysteine distribution, after adjusting for only age and sex or for the full adjustment (age, sex, smoking, systolic blood pressure, total cholesterol, fibrinogen, C-reactive protein and interleukin-6). The odds ratios produced by the two adjustments were similar. Comparing the top quarter with the bottom quarter of homocysteine, the odds ratio was 2.21 (95% confidence interval: 1.30-3.76) after the full adjustment. The odds ratio for a 5 micromol/l increase in homocysteine was 1.12 (95% confidence interval: 1.01-1.24) after the full adjustment. CONCLUSION: This study suggests that homocysteine has an effect on cardiovascular risk over and above that of inflammatory markers and the major cardiovascular risk factors.