Multidetector Computed Tomography Perfusion in Head and Neck Squamous Cell Carcinomas: Evaluation of a Dose Reduction Strategy

Abstract

Background Computed tomography perfusion (CTp), a useful technique in oncology, is not widely utilized due to the high radiation dose delivered from it. It involves scanning the region of interest every second for 50 seconds following intravenous contrast administration. Doubling sampling interval (SI) to 2 seconds will half the radiation dose, but may impact its effectiveness, which needs to be evaluated. Objectives To evaluate a dose reduction strategy in CTp by determining agreement between standard dose (SD) CTp (acquisition with SI 1 second) and low-dose CTp techniques with SI of 2 seconds (achieved either by reconstruction only or true low-dose acquisition). Materials and methods This cross-sectional study was conducted on histopathology-proven head and neck squamous cell carcinoma (HNSCC) patients who underwent CTp on 64 slice multidetector CT. A total of 56 patients had SD and 24 patients underwent true low dose (LD) acquisition. SD data were also reconstructed at SI 2 seconds to obtain a dataset simulating low dose (low-dose reconstruction [LDr]). Paired t-test was applied to compare CTp in SD and LDr groups and the Bland–Altman plot drawn to calculate 95% confidence limit of agreement. The Kolmogorov–Smirnov test compared CTp parameters for LDr and LD groups. Results There was no statistical difference in CTp parameters (except blood flow in malignant) in SD and LDr groups for both malignant and normal tissues. CTp of malignant tissue was not statistically different in LDr and LD groups but the radiation dose was half in the LD group. Conclusion Reduction of radiation dose to half achieved by doubling the SI does not affect the CTp parameters significantly. So LD acquisitions will increase the use of CTp in HNSCC.

Insight on common forms of cutaneous head and neck carcinoma (Review)

“…In severe radiation dermatitis (grades III or IV), the epidermis is infiltrated with neutrophils and there are high rates of apoptosis in the deeper layers (43). The standard administration of radiation involves successive doses and it frequently prevents tissue healing due to cellular repopulation, even if the patient takes a few days to break during cures of daily fractionated therapy, thereby compromising the result (44). The general management of radiation dermatitis includes washing once or twice a day with pH-5 soap, moisturizing shaving to prevent folliculitis, debridement and checking for systemic inflammation (45).…”