Multi-parametric magnetic resonance imaging assessment of whole tumour heterogeneity for chemoradiotherapy response prediction in rectal cancer.

BACKGROUND AND PURPOSE: Prediction of chemoradiotherapy response (CRT) in locally advanced rectal cancer would enable stratification of management. The purpose was to prospectively evaluate multi-parametric magnetic resonance imaging (MRI) assessment of tumour heterogeneity combining diffusion weighted imaging (DWI) and dynamic contrast enhanced (DCE) MRI for the prediction of CRT response in locally advanced rectal cancer. MATERIALS AND METHODS: Patients with Stage II or III rectal adenocarcinoma undergoing neoadjuvant CRT and surgery underwent MRI (DWI and DCE) before, during (week 3), and after CRT (1 week before surgery). Patients with histopathology tumour regression grade (TRG) 0-1 were classified as responders, and TRG 2-3 were classified as non-responders. A whole tumour voxel-wise technique was used to produce apparent diffusion coefficient (ADC) and Ktrans (Tofts model) histograms derived from DWI and DCE-MRI, respectively. Logistic regression was used to predict response status for ADC and Ktrans quantiles. RESULTS: Thirty-three patients were included in this analysis; 16 responders, and 17 non-responders. On heterogeneity analysis, odds of being a responder were significantly higher after CRT (before surgery) for higher ADC 75th (p = 0.049) and ADC 90th (p = 0.034) percentile values. The Ktrans quantiles were lower in non-responders than responders before and during CRT, and higher after CRT although no significant association with response status was observed (p ≥ 0.10). CONCLUSIONS: DWI-MRI after CRT (before surgery) incorporating a histogram analysis of whole tumour heterogeneity was predictive of CRT response in patients with locally advanced rectal cancer. DCE-MRI did not add value in response prediction. CLINICAL TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR) number ACTRN12616001690448.

Dural metastasis demonstrated on Tc-99m MDP bone scintigraphy in staging workup for a patient with breast cancer.

An 80-year-old woman with multifocal invasive lobular carcinoma of the right breast treated 6 years previously with mastectomy, locoregional radiotherapy, and tamoxifen was referred for a bone scan to investigate generalized arthralgias. The patient reported right-sided headaches, blurred vision, and dizziness in the previous 3 months. The bone scan revealed a large area of unusual and abnormal Tc-99m methylene diphosphonate (MDP) uptake in the right frontoparietal skull region. CT and MRI of the brain were performed to evaluate the possibility of cerebral metastases. The CT revealed extensive abnormal thickening and enhancement of the dura in the right frontoparietal region. No calcification of the dura or bony destruction of the overlying skull was evident on CT. MRI similarly revealed extensive thickening and irregularity of the dura. The usual causes of increased skull Tc-99m MDP uptake on bone scanning such as skull metastases and dural calcification were not evident on CT or MRI.

Renal scintigraphy unraveled the diagnostic dilemma of antenatal hydronephrotic solitary kidney-crossed renal ectopia.

On antenatal ultrasound assessment, an apparently solitary hydronephrotic kidney was identified, confirmed on postnatal ultrasound examination. More detailed postnatal investigations revealed the diagnosis of crossed renal ectopia.