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Introduction: Dynamic susceptibility contrast (DSC) perfusion weighted (PW)-MRI can aid in differentiating treatment related abnormalities (TRA) from tumor progression (TP) in post-treatment glioma patients. Common methods, like the 'hot spot', or visual approach suffer from oversimplification and subjectivity. Using perfusion of the complete lesion potentially offers an objective and accurate alternative. This study aims to compare the diagnostic value and assess the subjectivity of these techniques. Methods: 50 Glioma patients with enhancing lesions post-surgery and chemo-radiotherapy were retrospectively included. Outcome was determined by clinical/radiological follow-up or biopsy. Imaging analysis used the 'hot spot', volume of interest (VOI) and visual approach. Diagnostic accuracy was compared using receiving operator characteristics (ROC) curves for the VOI and 'hot spot' approach, visual assessment was analysed with contingency tables. Inter-operator agreement was determined with Cohens kappa and intra-class coefficient (ICC). Results: 29 Patients suffered from TP, 21 had TRA. The visual assessment showed poor to substantial inter-operator agreement (κ = -0.72 – 0.68). Reliability of the 'hot spot' placement was excellent (ICC = 0.89), while reference placement was variable (ICC = 0.54). The area under the ROC (AUROC) of the mean- and maximum relative cerebral blood volume (rCBV) (VOI-analysis) were 0.82 and 0.72, while the rCBV-ratio ('hot spot' analysis) was 0.69. The VOI-analysis had a more balanced sensitivity and specificity compared to visual assessment. Conclusions: VOI analysis of DSC PW-MRI data holds greater diagnostic accuracy in single-moment differentiation of TP and TRA than 'hot spot' or visual analysis. This study underlines the subjectivity of visual placement and assessment. [ABSTRACT FROM AUTHOR]

Volumes of interest (VOI) are commonly assigned to image stacks generated from micro-computed tomography to specify areas for bone quantification. However, the size of the VOI can impact the values obtained for trabecular bone parameters. This study aims to investigate the effect of VOI size by applying VOIs of four different diameters (10%, 15%, 20% and 30% of the antero-posterior width). Ten juvenile right distal femora were included, aged from pre-natal to three years. Smaller VOIs were placed within the largest VOI, with multiple locations used for the same VOI size. The observed parameters included bone volume fraction (BV/TV), trabecular bone thickness (Tb.Th), separation (Tb.Sp), number (Tb.N), degree of anisotropy by mean intercept length (DA.MIL) and star volume distribution (DA.SVD). Statistically significant differences between VOI sizes were found for Tb.Sp, Tb.N, DA.MIL and DA.SVD. A possible effect of localized variation was found due to significantly different values for Tb.Th between VOI locations. The effect related to VOI geometry was reflected by DA.MIL and DA.SVD as no significant difference was found between locations. The minimum diametric strut quantity (DSQ, diameter multiplied by Tb.N) of 4 can be implied based on the zero DA.SVD value found in particular VOIs. [ABSTRACT FROM AUTHOR]

This paper explores a technique for visually/diagnostically lossless coding in the wavelet domain to effectively compress the three-dimensional medical image data. The quantisation module based on Just Noticeable Distortion (JND) for wavelets guarantees the visual quality in the reconstructed data. This method has been further extended to present the Volume of Interest (VOI) based technique that enables to preserve the quality of the diagnostically significant VOI region. The proposed method tested on several datasets outperforms the state-of-the-art methods. Apart from the conventional quality metric, Human Visual System (HVS) based quality metrics are also used to evaluate the visual quality of the reconstructed image. A subjective and objective evaluation carried out for VOI based coder shows that the quality-compression needs of the medical community are well addressed. [ABSTRACT FROM AUTHOR]

Objective To assess the prediction value of a nomogram model constructed by gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI signatures combined with the mean T1 relaxation time of tumor and the peritumor dual-region for microvascular invasion of hepatocellular carcinoma.Methods Seventy-two patients with solitary hepatocellular carcinoma (HCC) underwent preoperative Gd-EOB-DTPA-enhanced MRI and curative liver resection in our hospital from January 2019 to September 2022.The patients were divided to two groups with (MVI+, 23) and without (MVI-, 49) microvascular invasion (MVI).The clinical information and MRI were retrospectively analyzed.Multivariate logistic analyses were used to screen out independent risk factors that could predict MVI.Two models were constructed with (T1 model) or without (no T1 model) inclusion of T1 relaxation time and their diagnostic efficacy was evaluated using a subject operating curve, calibration curve and decision curve.Net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were used to evaluate the differences between models and to select the optimal model to construct a nomogram.Results There was significant difference between the MVI-and MVI+groups in tumor margin (P＜0.001), tumor capsule (P=0.010), mosaic architecture (P=0.015), peritumoral enhancement in the arterial phase (P=0.018), peritumoral hypointensity in the hepatobiliary phase (P＜0.001), preoperative alpha-fetoprotein (P=0.003), tumor size (P＜0.001), T1 P+tumor (P=0.001), T1 E+tumor (P=0.009), T1 P+10 mm (P=0.014), T1 P+tumor+10 mm (P＜0.001), T1 E+tumor+10 mm (P=0.001), T1 P+tumor+20 mm (P=0.001), T1 E+tumor+20 mm (P=0.002) and T1D%tumor+20 mm (P=0.035).Multivariate logistic regression analysis showed that tumor margin (P=0.005;OR=10.391), peritumoral enhancement in the arterial phase (P=0.020;OR=7.729), peritumoral hypointensity in the hepatobiliary phase (P=0.003;OR=12.891) and T1 P+tumor+10 mm (P=0.026;OR=1.006)were independent risk factors for the occurrence of MVI in hepatocellular carcinoma.The areas under the ROC curves were 0.906 (0.840-0.973) for the no T1 model and 0.928 (0.873-0.984) for the T1 model.The calibration curve showed that the predicted probability was in good agreement with the MVI+/MVI-probability of the pathological results.The decision curve analysis displayed a more satisfactory net benefit rate of T1 model than that of no T1 model.The T1 model increased NRI by 0.4366 and IDI by 0.0689 compared to the no T1 model.Conclusion Gd-EOB-DTPA-enhanced MRI can be used to predict HCC MVI effectively.The combination of T1 P+tumor+10 mmin the nomogram model further improves the predictive efficacy of hepatocellular carcinoma MVI. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this retrospective study was to evaluate the relationship between bone mineral density (BMD), as assessed with dual-energy x-ray absorptiometry (DEXA), and Hounsfield units (HU) measured in volumes of interest (VOIs) and regions of interest (ROIs) on lumbar spine CT., Methods: A retrospective analysis was performed on data of lumbar vertebrae obtained from patients who underwent both DEXA and lumbar spine CT scan within a 6-month period. Vertebrae with a history of compression fracture, infectious spondylitis, cement reinforcement, or lumbar surgery were excluded. HU measurements were performed in the VOI and ROI (midaxial, midcoronal, and midsagittal sections) with CT, whereas BMD was assessed with DEXA. Statistical analyses, including correlation assessments and receiver operating characteristic (ROC) curve analyses, were performed., Results: This analysis included 712 lumbar vertebrae, with a median patient age of 72.0 years. BMD values and HU measurements in the VOI increased sequentially from L1 to L4, whereas HU values in the ROI did not show a consistent pattern. HU values in the VOI consistently showed a stronger correlation with BMD than those in the ROI. ROC analysis revealed patient-level cutoff values for the diagnosis of osteoporosis at different lumbar vertebral levels with high sensitivity and specificity, as well as an excellent area under the curve., Conclusions: This is the first study to introduce a novel approach using the HU value in the VOI to assess bone health at the lumbar spine. There is a strong correlation between the HU value in the VOI and BMD, and the HU value in the VOI can be used to predict osteoporosis.