Tumour heterogeneity in non-small cell lung carcinoma assessed by CT texture analysis: a potential marker of survival.

PURPOSE: To establish the potential for tumour heterogeneity in non-small cell lung cancer (NSCLC) as assessed by CT texture analysis (CTTA) to provide an independent marker of survival for patients with NSCLC. MATERIALS AND METHODS: Tumour heterogeneity was assessed by CTTA of unenhanced images of primary pulmonary lesions from 54 patients undergoing (18)F-fluorodeoxyglucose (FDG) PET-CT for staging of NSCLC. CTTA comprised image filtration to extract fine, medium and coarse features with quantification of the distribution of pixel values (uniformity) within the filtered images. Receiver operating characteristics identified thresholds for PET and CTTA parameters that were related to patient survival using Kaplan-Meier analysis. RESULTS: The median (range) survival was 29.5 (1-38) months. 24, 10, 14 and 6 patients had tumour stages I, II, III and IV respectively. PET stage and tumour heterogeneity assessed by CTTA were significant independent predictors of survival (PET stage: Odds ratio 3.85, 95% confidence limits 0.9-8.09, P = 0.002; CTTA: Odds ratio 56.4, 95% confidence limits 4.79-666, p = 0.001). SUV was not a significantly associated with survival. CONCLUSION: Assessment of tumour heterogeneity by CTTA of non-contrast enhanced images has the potential for to provide a novel, independent predictor of survival for patients with NSCLC. KEY POINTS: Computed tomography is a routine staging procedure in non-small cell lung cancer. CT texture analysis (CTTA) can quantify heterogeneity within these lung tumours. CTTA seems to offer a novel independent predictor of survival for NSCLC. CTTA could contribute to disease risk-stratification for patients with NSCLC.

Clinical evaluation of a phalangeal bone mineral density assessment system.

Because osteoporosis is common and usually managed in primary care, there is a requirement for cheap and convenient methods of measuring bone mineral density (BMD). AccuDEXA (Lone Oak Medical Technologies, Doylestown, PA) is a tabletop dual-energy X-ray absorptiometry (DXA) device that performs BMD measurements of the hand in the middle phalanges of the third finger. The aims of this study were to (1) evaluate the use of AccuDEXA in UK women; (2) investigate the concordance between AccuDEXA T-scores and DXA T-scores for central (spine and hip) sites; (3) investigate the comparative response of AccuDEXA measurements to clinical risk factors for osteoporosis. Measurements of phalangeal and central BMD were performed in 620 women referred by their family doctors for bone densitometry (group 1) and 159 healthy female volunteers (group 2). For 65 women in group 2, aged 39 yr or younger, the mean Z-scores for AccuDEXA and the central sites calculated from US reference ranges were consistent with the expected value of 0, whereas for the 62 group 2 women, aged 50 yr or older, the mean Z-scores for AccuDEXA and the central sites were in the range 0.4-0.7 and were statistically significantly different from 0. In both group 1 and group 2, the AccuDEXA T-scores in older and younger women were systematically higher than those in the central sites by up to 1 unit. Of the 157 women aged 50 yr or older, with osteoporosis, based on their central DXA results, only 34 (22%) had an AccuDEXA T-score less than or equal to -2.5, whereas 76 (48%) had osteopenia and 47 (30%) were normal based on their AccuDEXA T-scores. When assessed by the effect of clinical risk factors on Z-scores, both AccuDEXA and central BMD were affected to a similar extent. We conclude that the conventional World Health Organisation T-score criteria for the diagnosis of osteoporosis should not be applied to AccuDEXA measurements in UK women. Clinical risk factors for low BMD were found to affect AccuDEXA measurements to a similar extent as central BMD measurements. AccuDEXA measurements could, therefore, provide an alternative method for identifying individuals with low bone mass, provided care is taken in interpreting T-scores, perhaps, through the use of device-specific thresholds.