Effect of laterality, gender, age and body mass index on the fat fraction of salivary glands in healthy volunteers: assessed using iterative decomposition of water and fat with echo asymmetry and least-squares estimation method

Objective Iterative decomposition of water and fat with echo asymmetry and least-squares estimation-iron quantification (IDEAL-IQ) is a noninvasive and objective method used to quantitatively measure fat content. Although this technique has been used in the entire abdomen, IDEAL-IQ findings in the sacroiliac joint (SIJ) have rarely been reported. This preclinical study was performed to quantify the amount of fat in the SIJ in healthy volunteers by IDEAL-IQ. Methods From April to November 2017, 60 healthy volunteers with low back pain were included in this retrospective study. The participants were allocated into groups by age (15–30, 31–50, and ≥51 years), sex (male and female), and body mass index (BMI) (<18.5, 18.5–23.9, and ≥24.0 kg/m2). The iliac-side (Fi) and sacral-side (Fs) fat fractions were obtained in all groups. Two- and three-factor multivariate analyses were performed to analyze the effects of sex, age, and BMI on the Fi and Fs. Results The interaction among sex, age, and BMI had no statistically significant effect on the dependent variable. Both Fi and Fs were significantly influenced by age. Fs was significantly influenced by sex. Conclusion The IDEAL-IQ sequence can be used to quantitatively assess the SIJ fat content in healthy volunteers.

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Assessment of bone marrow fat fractions in the mandibular condyle head using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) method

PLoS ONE ◽

10.1371/journal.pone.0246596 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246596

Author(s):

Kug Jin Jeon ◽

Chena Lee ◽

Yoon Joo Choi ◽

Sang-Sun Han

Keyword(s):

Bone Marrow ◽

Least Squares ◽

Temporomandibular Joint ◽

Mandibular Condyle ◽

Least Squares Estimation ◽

Control Group ◽

Dixon Method ◽

Iterative Decomposition ◽

Iq Method ◽

Decomposition Of Water

The prevalence of temporomandibular joint disorder (TMD) is gradually increasing, and magnetic resonance imaging (MRI) is becoming increasingly common as a modality used to diagnose TMD. Edema and osteonecrosis in the bone marrow of the mandibular condyle have been considered to be precursors of osteoarthritis, but these changes are not evaluated accurately and quantitatively on routine MRI. The iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) method, as a cutting-edge MRI technique, can separate fat and water using three asymmetric echo times and the three-point Dixon method. The purpose of this study was to analyze the quantitative fat fraction (FF) in the mandibular condyle head using the IDEAL-IQ method. Seventy-nine people who underwent MRI using IDEAL-IQ were investigated and divided into 1) the control group, without TMD symptoms, and 2) the TMD group, with unilateral temporomandibular joint (TMJ) pain. In both groups, the FF of the condyle head in the TMJ was analyzed by two oral and maxillofacial radiologists. In the TMD group, 29 people underwent cone-beam computed tomography (CBCT) and the presence or absence of bony changes in the condylar head was evaluated. The FF measurements of the condyle head using IDEAL-IQ showed excellent inter-observer and intra-observer agreement. The average FF of the TMD group was significantly lower than that of the control group (p < 0.05). In the TMD group, the average FF values of joints with pain and joints with bony changes were significantly lower than those of joints without pain or bony changes, respectively (p < 0.05). The FF using IDEAL-IQ in the TMJ can be helpful for the quantitative diagnosis of TMD.

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