BACKGROUND: Osteoporosis (OP) is a common chronic metabolic bone disease characterized by decreased bone mineral content and microstructural damage, leading to increased fracture risk. Traditional methods for measuring bone density have limitations in accurately distinguishing vertebral bodies and are influenced by vertebral degeneration and surrounding tissues. Therefore, novel methods are needed to quantitatively assess changes in bone density and improve the accurate diagnosis of OP.
METHODS: This study aimed to explore the applicative value of the iterative decomposition of water and fat with echo asymmetry and least-squares estimation-iron (IDEAL-IQ) sequence combined with intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for the diagnosis of osteoporosis. Data from 135 patients undergoing dual-energy X-ray absorptiometry (DXA), IDEAL-IQ, and IVIM-DWI were prospectively collected and analyzed. Various parameters obtained from IVIM-DWI and IDEAL-IQ sequences were compared, and their diagnostic efficacy was evaluated.
RESULTS: Statistically significant differences were observed among the three groups for FF, R2*, f, D, DDC values, and BMD values. FF and f values exhibited negative correlations with BMD values, with r=-0.313 and - 0.274, respectively, while R2*, D, and DDC values showed positive correlations with BMD values, with r = 0.327, 0.532, and 0.390, respectively. Among these parameters, D demonstrated the highest diagnostic efficacy for osteoporosis (AUC = 0.826), followed by FF (AUC = 0.713). D* exhibited the lowest diagnostic performance for distinguishing the osteoporosis group from the other two groups. Only D showed a significant difference between genders. The AUCs for IDEAL-IQ, IVIM-DWI, and their combination were 0.74, 0.89, and 0.90, respectively.
CONCLUSIONS: IDEAL-IQ combined with IVIM-DWI provides valuable information for the diagnosis of osteoporosis and offers evidence for clinical decisions. The superior diagnostic performance of IVIM-DWI, particularly the D value, suggests its potential as a more sensitive and accurate method for diagnosing osteoporosis compared to IDEAL-IQ. These findings underscore the importance of integrating advanced imaging techniques into clinical practice for improved osteoporosis management and highlight the need for further research to explore the full clinical implications of these imaging modalities.

Aim  Osteoporosis is a common metabolic bone disease accounting for low back pain (LBP). It is diagnosed by dual-energy X-ray absorptiometry (DXA). Magnetic resonance imaging (MRI), a routine investigation for LBP, is also sensitive to detect fat fraction (FF) of the vertebral body that increases with increasing age. This study aimed to correlate vertebral marrow FF using MRI and bone mineral density (BMD). Material and Methods  Patients presenting with low backache and suspected osteoporosis were included. All patients underwent an MRI of lumbosacral spine and DXA. Patients were categorized into an osteoporotic and a nonosteoporotic group based on the T-score obtained from DXA. \"T-scores\" of < -2.5 on BMD were considered as osteoporotic spine. T-score of > -2.5 was considered as nonosteoporotic. The FF obtained from the DIXON sequence of MRI was correlated between the two groups. Result  Thirty-one patients were included with a mean age of 54.26 ± 11.6 years. Sixteen patients were osteoporotic based on the defined criteria in the methods. The mean vertebral marrow FF was significantly higher in the osteoporotic patients (64.98 ± 8.8%) compared with the nonosteoporotic (45.18 ± 13.2%) ( p  = 0.001). The mean FF of the vertebra having fracture (69.19 ± 7.73%) was significantly higher than that of patients without fracture (57.96 ± 5.75%) ( p  = 0.03). Taking a cutoff value of vertebral marrow FF of 54.85, the sensitivity and specificity of diagnosing osteoporosis were 93 and 80%, respectively, with a confidence interval of 95%. The area under the curve was 0.925. Conclusion  Increased vertebral marrow FF is noted in the osteoporotic spine. FF has an inverse correlation with the T-score obtained from BMD. MRI with FF measurement can provide indirect evidence of osteoporosis, which can be done under one roof, especially in young patients where we need to avoid ionizing radiation.

Severe sarcopenia may result in severe disability. Early diagnosis is currently the key to enhancing the treatment of sarcopenia, and there is an urgent need for a highly sensitive and dependable tool to evaluate the course of early sarcopenia in clinical practice. This study aims to investigate longitudinally the early diagnosability of magnetic resonance imaging (MRI)-based fat infiltration and blood flow perfusion technology in sarcopenia progression.
48 Sprague-Dawley rats were randomly assigned into six groups that were based on different periods of dexamethasone (DEX) injection (0, 2, 4, 6, 8, 10 days). Multimodal MRI was scanned to assess muscle mass. Grip strength and swimming exhaustion time of rats were measured to assess muscle strength and function. Immunofluorescence staining for CD31 was employed to assess skeletal muscle capillary formation, and western blot was used to detect vascular endothelial growth factor-A (VEGF-A) and muscle ring finger-1 (MuRF-1) protein expression. Subsequently, we analyzed the correlation between imaging and histopathologic parameters. A receiver operating characteristic (ROC) analysis was conducted to assess the effectiveness of quantitative MRI parameters for discriminating diagnosis in both pre- and post-modeling of DEX-induced sarcopenic rats.
Significant differences were found in PDFF, R2* and T2 values on day 2 of DEX-induction compared to the control group, occurring prior to the MRI-CSA values and limb grip strength on day 6 of induction and swimming exhaustion time on day 8 of induction. There is a strong correlation between MRI-CSA with HE-CSA values (r = 0.67; p < 0.001), oil red O (ORO) area with PDFF (r = 0.67; p < 0.001), microvascular density (MVD) (r = -0.79; p < 0.001) and VEGF-A (r = -0.73; p < 0.001) with R2*, MuRF-1 with MRI-CSA (r = -0.82; p < 0.001). The AUC of PDFF, R2*, and T2 values used for modeling evaluation are 0.81, 0.93, and 0.98, respectively.
Imaging parameters PDFF, R2*, and T2 can be used to sensitively evaluate early pathological changes in sarcopenia. The successful construction of a sarcopenia rat model can be assessed when PDFF exceeds 1.25, R2* exceeds 53.85, and T2 exceeds 33.88.

UNASSIGNED: This study aimed to analyze the quantitative fat fraction (FF) of the parotid gland in menopausal females with xerostomia using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) method.
UNASSIGNED: A total 138 parotid glands of 69 menopausal females were enrolled in our study and participants were divided into normal group and xerostomia group. The xerostomia group was divided into those with or without Sjögren\'s syndrome. Participants underwent IDEAL-IQ sequences of MRI and the stimulated salivary flow test (s-SFR). The unpaired t-test was used to compare the FFs between the normal and xerostomia groups and between the subgroups with and without Sjögren\'s syndrome. The correlation between FF and s-SFR was analyzed by Pearson\'s correlation.
UNASSIGNED: Excellent intra- and interobserver agreement during the measurement of FFs by IDEAL-IQ method (ICC>0.99, respectively). FF value in the xerostomia group was statistically significantly higher than the value in the normal group (p < 0.05). Within the xerostomia group, the average FF value of females with Sjögren\'s syndrome was higher than that of females without Sjögren\'s syndrome. However, the difference was not statistically significant (p > 0.05). Within the xerostomia group, FF value correlated negatively with s-SFR (p < 0.05).
UNASSIGNED: The FF of the parotid gland was higher in the xerostomia group than in the normal group and FF value and s-SFR showed a negative correlation. Analyses of the FF using IDEAL-IQ in menopausal females can be helpful for the quantitative diagnosis of xerostomia.

OBJECTIVE: This study investigated the correlation of liver fat content (LFC) with metabolic characteristics and its association with chronic complications in type 2 diabetes mellitus (T2DM) patients.
METHODS: Eighty-one prospectively enrolled T2DM patients were divided into non-alcoholic fatty liver disease (NAFLD) group and the non-NAFLD group according to the presence of NAFL complications. LFC was determined by MRI IDEAL-IQ Sequence, and patients were divided into 4 groups according to LFC by quartile method. Basic information, metabolic indexes, and occurrence of chronic complications in different groups were analyzed and compared.
RESULTS: BMI, SBP, DBP, TG, ALT, AST, GGT, UA, HbA1c, FCP, 2 h CP, HOMA-IR, and HOMA-IS in the NAFLD group were significantly higher than the non-NAFLD group (P < 0.05). The incidences of chronic complications in the NAFLD group were higher than in the non-NAFLD group but not statistically significant (P > 0.05). BMI, SBP, DBP, TC, TG, ALT, AST, FCP, 2 h CP, HOMA-IR, and HOMA-IS showed significant differences between the patients with different LFC, and these indexes were significantly higher in patients with higher LFC than those with lower LFC (P < 0.05). Moreover, diabetes duration, TC, HOMA-IR, and LFC were the risk factors for ASCVD complications, while diabetes duration, TG, and LDL-C were risk factors for DN complications. Also, diabetes duration and SBP were risk factors for both DR and DPN complications in T2DM patients (P < 0.05).
CONCLUSIONS: LFC is positively correlated with the severity of the systemic metabolic disorder and chronic complications in T2DM patients.

OBJECTIVE: To evaluate the performance of a chemical shift-encoded sequence called IDEAL-IQ for detecting sacroiliac joint (SIJ) erosions and fat metaplasia compared to T1-weighted fast spin echo (T1 FSE) using qualitative and quantitative analysis.
METHODS: Thirty-four patients with suspicion of sacroiliitis who underwent both MRI and CT were included. Each SIJ was divided into four quadrants for analysis. For qualitative analysis, the diagnostic performance of IDEAL-IQ and T1 FSE for erosions were compared by the McNemar test, using CT as the gold standard. Cochran\'s Q and McNemar tests were used to determine differences in structural changes detected by different imaging methods. For quantitative analysis, two-sample t test and receiver operating characteristic (ROC) analysis were used for the analysis of histogram parameters of proton density fat fraction (PDFF).
RESULTS: Diagnostic sensitivity and accuracy of IDEAL-IQ were greater than T1 FSE for erosions (all P < 0.05). IDEAL-IQ and CT detected more erosions than T1 FSE (all P < 0.05). IDEAL-IQ did not statistically significantly differ from T1 FSE for the detection of fat metaplasia (P = 0.678). All histogram parameters were different between groups with and without fat metaplasia (all P < 0.05) and could distinguish the two groups (all P < 0.05). PDFF75th was the most effective histogram parameter.
CONCLUSIONS: IDEAL-IQ detects SIJ erosions with better accuracy than T1 FSE and is similar to T1 FSE for detection of fat metaplasia, enabling further quantitative analysis of the latter via histogram analysis.

UNASSIGNED: Chronic kidney disease (CKD) has a significant negative impact on bone health. Bone marrow is an essential component of bone, mainly composed of trabecular bone and fat. The IDEAL-IQ sequence of MRI allows indirect quantification of trabecular bone mass by R2* and direct quantification of bone marrow fat content by FF map, respectively.
UNASSIGNED: Our objective was to explore the association of CKD severity with bone marrow using IDEAL-IQ and whether mineral and bone metabolism markers alter this association.
UNASSIGNED: We recruited 68 CKD patients in this cross-sectional research (15 with CKD stages 3-4, 26 with stage 5, and 27 with stage 5d). All patients underwent lumbar spine IDEAL-IQ, BMD, and several bone metabolism markers (iPTH, 25-(OH)-VitD, calcium and phosphorus). Multiple linear regression analysis was used to examine the association of CKD severity with MRI measurements (R2* and FF).
UNASSIGNED: More severe CKD was associated with a higher R2* value [CKD 5d versus 3-4: 30.077 s-1 (95% CI: 12.937, 47.217), P for trend < 0.001], and this association was attenuated when iPTH was introduced [CKD 5d versus 3-4: 19.660 s-1 (95% CI: 0.205, 39.114), P for trend = 0.042]. Furthermore, iPTH had an association with R2* value [iPTH (pg/mL): 0.033 s-1 (95% CI: 0.001, 0.064), P = 0.041]. Besides, FF was mainly affected by age and BMI, but not CKD.
UNASSIGNED: The bone marrow R2* value measured by IDEAL-IQ sequence is associated with CKD severity and iPTH. The R2* of IDEAL-IQ has the potential to reflect lumbar bone changes in patients with CKD.

OBJECTIVE: To investigate the accuracy of using multi-material decomposition (MMD) algorithm in dual-energy spectral computed tomography (CT) for quantifying fat fraction (FF) in the presence of iron.
METHODS: Nine tubes with various proportions of fat and iron were prepared. FF were divided into three levels (10%, 20%, and 30%), recorded as references (FFref ). Iron concentrations (in mg/100 g) were divided into three ranges (25.25-25.97, 50.38-51.55 and 75.57-77.72). The nine-tube phantom underwent dual-energy CT and MR. CT attenuation was measured and FF were determined using MMD in CT (FFCT ) and Iterative Decomposition of water and fat with Echo Asymmetry and Least squares estimation (IDEAL-IQ) in MR (FFMR ) for each tube. Statistical analyses used were: Spearman rank correlation for correlations between FFref and CT attenuation, FFCT , and FFMR ; one-way ANOVA, and one-sample t-test for the differences between FFCT and FFref and between FFMR and FFref . A multivariate linear regression model was established to analyze the differences between the corresponding values with different iron concentrations under the same FFref .
RESULTS: Fat fraction on CT (FFCT) and FFMR were positively correlated with FFref (all p < 0.001), while the CT attenuation was negatively correlated with FFref in the three iron concentration ranges. For a given FFref , FFCT decreased and FFMR increased as the iron concentration increased. The mean difference between FFCT and FFref over the nine tube measurements was 0.25 ± 2.45%, 5.7% lower the 5.98 ± 3.33% value between FFMR and FFref (F = 310.017, p < 0.01).
CONCLUSIONS: The phantom results indicate that MMD in dual-energy CT can directly quantify volumetric FF and is less affected by iron concentration than MR IDEAL-IQ method.

Skeletal muscle mass measurement is the most important element for diagnosing sarcopenia. MRI has an excellent soft-tissue contrast, which can non-invasively assess abdominal skeletal muscle area (SMA) as well as CT. This study aimed to assess the validity and reliability of abdominal SMA measurement by comparing CT and MRI based on the fat image of IDEAL-IQ sequence at the lumbar level mid-L3.
CT and MRI images of 32 patients diagnosed with various kidney diseases were used to analyze intra-observer variability among abdominal SMA measurements. This was done to evaluate the correlation of SMA between CT and fat images of MRI. SMA images were segmented using Materialise Mimics software before quantification. Interobserver reliability and validation of measurements was evaluated by two independent investigators. Abdominal SMA reproducibility and correlation between CT and MRI were then assessed using the intraclass correlation coefficient (ICC), coefficient of variation (CV), Bland-Altman plot, and Pearson\'s correlation coefficient respectively.
The interobserver reliability of MRI was excellent. The CV value was 2.82% while the ICC values ranged between 0.996 and 0.999. Validity was high (CV was 1.7% and ICC ranged between 0.986 and 0.996) for measurements by MRI and CT. Bland Altman analysis revealed an average difference of 2.2% between MRI and CT. The Pearson\'s correlation coefficient was 0.995 (p < 0.0001). This result revealed that there was a strong correlation between the two technologies.
MRI exhibited good interobserver reliability and excellent agreement with CT for quantification of abdominal SMA.

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.
CONCLUSIONS: The IDEAL-IQ sequence can be used to quantitatively assess the SIJ fat content in healthy volunteers.