Non-linear image blending improves visualization of head and neck primary squamous cell carcinoma compared to linear blending in dual-energy CT.

AIM: To compare non-linear and linear image-blending post-processing techniques in dual-energy CT (DECT) of primary head and neck squamous cell carcinoma (SCC) regarding subjective and objective image quality. MATERIALS AND METHODS: Head and neck DECT studies from 69 patients (48 male, 21 female; mean age 62.3 years) were retrospectively evaluated. All tumour lesions were histologically confirmed SCC. Linearly blended 80/140 kVp images series with varying weighting factors of 0.3 (M_0.3), 0.6 and 0.8 were compared with non-linearly blended images. Attenuation of tumour lesion, various soft-tissue structures, the internal jugular vein, and image noise were measured, tumour signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Overall image quality, delineation of tumour lesion, image sharpness, and noise level were rated individually by three radiologists using five-point Likert scales. Interobserver agreement was calculated using intraclass correlation coefficient (ICC). RESULTS: Enhancement of tumour lesions (non-linear, 137.5 ± 20.1 HU; M_0.3, 92.7 ± 14.4 HU; M_0.6, 110 ± 15.4 HU; M_0.8, 123 ± 18.2 HU), CNR (non-linear, 12 ± 8; M_0.3, 4 ± 4.7; M_0.6, 7.5 ± 5.5; M_0.8, 8 ± 5.5), subjective overall image quality and tumour delineation were significantly increased (all p < 0.001) with the non-linear blending technique compared to all investigated linear blending weighting factors. Overall interobserver agreement was substantial (ICC 0.70; 95% CI: 0.66-0.73). CONCLUSION: Post-processing of DECT using a non-linear blending technique provides improved objective and subjective image quality of head and neck SCC compared to linearly blended images series.

Skin response using NIH consensus criteria vs Hopkins scale in a phase II study for steroid-refractory chronic GVHD.

One of the obstacles to chronic GVHD research is the lack of standardized response criteria. The National Institute of Health (NIH) has recommended response criteria at a Consensus Conference. These need to be validated. We recently completed and reported a trial of pentostatin in treating steroid-refractory chronic GVHD. During the trial, we prospectively collected percent body-surface-area (BSA) involvement of rash, superficial sclerosis and deep sclerosis. Here, we compare cutaneous responses using the NIH scale and the Hopkins scale. The two scales produced similar overall response rates but different domain response rates. There was 80% agreement in overall response at the final treatment evaluation, but only a 64% agreement for fasciitis/non-moveable sclerosis. There was more disparity in the measurement of sclerosis than in that of erythema, which highlights the difficulty of quantifying sclerosis. For sclerosis, the Hopkins scale, which used skin softening, was more predictive of early response as compared with the NIH scale, which focused on percent BSA. Early assessment of skin softening may be important if trying to detect the activity of a particular agent in chronic GVHD. Further validation of the NIH scale is ongoing, which should produce a clinically useful and predictive scale.