Rhett Thomson, Utah Valley University
Health
Previous studies have shown high-frequency (HF) ultrasound may be sufficiently sensitive to detect and differentiate between both the histopathology and molecular subtypes of breast cancer. The goal of this study was to test the boundaries of HF ultrasonic testing methods. The parameter of interest was the effect of formalin fixation on tissue samples. Formalin has been found to stiffen tissues. Since ultrasound is sensitive to histological properties such as stiffness and adhesion factors, stiffening caused by fixation may compromise the results of the HF ultrasound analysis. This study monitored potential changes to HF measurements caused by tissue fixation. The fixation solution used was 10% neutral buffered formalin. The same formalin solution is used by hospitals after breast conserving surgery (BCS) to prepare and preserve excised tissue specimens for pathology. If no change in HF ultrasound analysis is detected in tissue samples before or after fixation, prepared tissue specimens from BCS patients may be used as viable samples for HF ultrasonic testing. Twenty tissue samples were used in this study. All samples were excised from the cortex, medulla, or ureter of a fresh cow kidney. Samples were tested with HF ultrasound. Testing conditions and procedures were identical to previous breast cancer tests. HF ultrasonic testing was completed at the zero hour mark and then repeated at five successive time intervals during fixation. Data collected from each sample was compared across all time intervals to detect any changes caused by fixation. Analysis of the data showed no significant changes in HF readings before, during, or after fixation up to 17 hours. Any variations observed were within experimental error. These findings demonstrate that formalin fixation does not affect the accuracy of HF ultrasonic testing techniques on bovine tissue samples. To reinforce the findings, this study will be repeated using different types of tissues.