Banca de DEFESA: NITHAELA ALVES BENNEMANN

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : NITHAELA ALVES BENNEMANN
DATE: 23/03/2026
TIME: 14:00
LOCAL: REMOTA
TITLE:

BODY COMPOSITION ASSESSMENT USING COMPUTED TOMOGRAPHY: CLINICAL FINDINGS AND THE ROLE OF IMAGE ACQUISITION PARAMETERS

KEY WORDS:

body composition, computed tomography, slice thickness, radiodensity, skeletal muscle, adipose tissue, colorectal cancer.

PAGES: 56
BIG AREA: Ciências da Saúde
AREA: Nutrição
SUMMARY:

Introduction: Computed tomography (CT) is considered a reference method for assessing body composition (BC). Despite its accuracy, technical parameters related to CT image acquisition are not widely discussed, which may hinder methodological standardization. Slice thickness is one of the parameters that may influence BC measurements. Patients with colorectal cancer (CRC) often present alterations in BC that are associated with poorer clinical outcomes. However, many studies analyze colon and rectal cancers together, regardless of staging, which may affect assessment and treatment strategies. Objective: This study aimed to evaluate BC using CT by investigating the impact of different CT slice thicknesses on BC measurements and by identifying BC differences in patients with CRC. Methods: Two cross-sectional studies were conducted. Study 1, derived from a retrospective multicenter cohort, evaluated CT-derived BC in patients with CRC treated at six oncology centers in Brazil, comparing BC variables according to tumor site (colon or rectum) and the presence or absence of metastases. Study 2 assessed the impact of different CT slice thicknesses on BC measurements in young and healthy individuals. Images were acquired at the third lumbar vertebra (L3) and reconstructed at different slice thicknesses (0.6, 1.25, 2.5, 5, and 10 mm). In both studies, BC was analyzed at the L3 level, including quantification of skeletal muscle area, intermuscular adipose tissue, visceral adipose tissue, and subcutaneous adipose tissue, as well as tissue radiodensity. Tissue analysis was performed using the semi-automatic mode of SliceOmatic® software (TomoVision). Statistical analyses included comparative tests and generalized linear models adjusted for potential confounders in Study 1, and repeated-measures ANOVA with Tukey’s post-hoc test to evaluate differences between slice thicknesses in Study 2. Results: In Study 1, 635 individuals were evaluated (mean age 61.8 ± 12.4 years; 50.2% female). Most participants had rectal cancer as the primary tumor site (51.0%), and 23.6% presented metastatic disease. The first regression model showed that tumor site and the presence of metastases were independent factors influencing skeletal muscle (SM), skeletal muscle index (SMI), and visceral adipose tissue (VAT) variability (all p < 0.05). The second model, adjusted for BMI, indicated tumor site as the main factor associated with SMI variation (adjusted R² = 0.50; p < 0.001), with colon tumors inversely viii associated with SM (standardized β −2.15 [−3.3; −0.9]; p < 0.001). A third model including all confounders identified through directed acyclic graphs confirmed the independence of this association. In Study 2, a total of 550 slices from 110 individuals were analyzed (56.4% female). Differences in radiodensity were observed between slice thicknesses for intermuscular and visceral adipose tissue (IMAT and VAT in HU) and for IMAT area (cm²). The most relevant differences occurred between thinner slices (0.6 and 1.25 mm) and the thickest slice (10 mm), with adjusted p-values < 0.001. No significant differences were found in skeletal muscle area across slice thicknesses. These results were consistent in analyses stratified by sex and BMI. Conclusion: The findings of this work demonstrate that CT-based BC assessment has both clinical and methodological relevance. Significant variations in BC among patients with CRC were associated with tumor location and the presence of metastases, highlighting the importance of considering these factors in clinical decision-making. Additionally, CT slice thickness may influence radiodensity measurements of adipose compartments, reinforcing the need for greater standardization of CT acquisition and analysis protocols to optimize the use of CT in BC assessment in clinical and research settings.

COMMITTEE MEMBERS:
Externo à Instituição - MIRKO SALOMÓN ALVA SÁNCHEZ - UFCSPA
Presidente - 1879430 - ANA PAULA TRUSSARDI FAYH
Externo à Instituição - NILIAN CARLA SILVA SOUZA - INCA