Volume analyzer synapse vincent 3d image analysis system

Skeletal muscle area was measured retrospectively on CT scans performed before chemotherapy and at initial routine CT scan up to 3 months after chemotherapy, at the level of the third lumbar vertebra (L3) in the inferior direction, with the patient in the supine position. Briefly, we measured pixels using a window width of −30 to 150 HU to delineate the muscle compartments and to compute their cross-sectional areas in cm² using the Volume Analyzer Synapse Vincent 3D image analysis system (Fujifilm Medical, Tokyo, Japan) (S1 Fig). The cross-sectional area of muscle (cm²) at the L3 level computed from each image was normalized by the square of the height (m²) to obtain the skeletal muscle index (cm²/m²). The rate of skeletal muscle change (%) between pre-treatment CT scan and first routine CT scan after chemotherapy was calculated. All measurements and calculations were performed independently by two trained examiners (Y.M. and Y. S.) who were blinded to the clinical outcomes at the time of quantification. Lin’s concordance correlation coefficient was 0.940 (95% confidence interval [CI], 0.922–0.954) (S1 Table).

Skeletal muscle area was measured retrospectively using images from CT performed before surgery at the third lumbar vertebra level in the inferior direction, with the patient in the supine position. We briefly measured the number of pixels using a window width of –30 to 150 HU to delineate muscle compartments and compute their cross‐sectional areas in cm² using the Volume Analyzer Synapse Vincent 3D image analysis system (Fujifilm Medical, Tokyo, Japan). The cross‐sectional area of the muscle (cm²) at the L3 level computed from each image was normalized by the square of the height (m²) to obtain the skeletal muscle index (SMI; cm²/m²).¹⁶, ¹⁷ We divided the patients into quartiles according to the SMI using a sex‐specific categorical variable (Q1 [males: 29.3–43.5, n = 38; females: 25.0–37.3, n = 26], Q2 [males: 43.6–50.3, n = 38; females: 37.3–41.8, n = 27], Q3 [males: 50.5–56.6, n = 38; females: 41.9–45.9, n = 26], and Q4 [males: 57.0–85.0, n = 37; females: 46.0–56.2, n = 26]). We defined the lowest SMI (Q1) as a sarcopenia condition.

CT scans at the level of the umbilicus that were taken a month prior to treatment initiation of PLD were used to calculate visceral adipose tissue area (VATA) and subcutaneous adipose tissue area (SATA) by the Volume Analyzer SYNAPSE VINCENT 3D image analysis system (FUJIFILM Medical). Tissue Hounsfield unit thresholds were set as follows: −190 to −30 for subcutaneous adipose tissue and −150 to −50 for visceral adipose tissue.²⁴ We estimated the visceral to subcutaneous adipose tissue area ratio (VSR), an indicator of intra‐abdominal visceral adipose tissue accumulation.²⁵, ²⁶ Body mass index (BMI) was also measured by dividing weight (in kilograms) by the square of height (in meters) immediately prior to the initiation of PLD treatment.