Comparison of 3T diffusion-weighted MRI and 18F-FDG PET/CT in musculoskeletal tumours: quantitative analysis of apparent diffusion coefficients and standardized uptake values

The expression of Ki-67 and Glypican -3 in hepatocellular carcinoma was evaluated by comparing DWI and 18F-FDG PET/CT

Objective

The value of DWI and 18F-FDG PET/CT in evaluating the expression of Ki-67 and GPC-3 in HCC was compared.

Materials and methods

Ninety-four patients with primary HCC confirmed by pathology were retrospectively divided into high- and low-Ki-67-expression groups and positive- and negative- GPC-3 groups. The ADC and SUVmax values of the lesions in both groups were measured. ROC curves were used to evaluate the identification efficiency of parameters with significant differences for each group of lesions, and AUCwas calculated. The combined ADC and SUVmax values were analyzed by binary logistic regression. The Delong test was used to compare the AUC values of the combined and single parameters. Pearson (in line with normal distribution) or Spearman (in line with abnormal distribution) correlation analysis was used to analyze the correlation.

Results

The ADC value of the high-Ki-67-expression group was lower than that of the low-Ki-67-expression group (P<0.05), and the SUVmax value of the high-expression group was higher than that of the low-expression group (P<0.05). The ADC value of the positive-GPC-3 group was lower than that of the negative group (P<0.0.tive group (P<0.05). The combined ADC and SUVmax values in the GPC-3 group were better than those of a single parameter (P<0.05). There was a strong negative correlation between the SUVmax value and ADC value in the Ki-67 group (R=-0.578, P<0.001) and a weak negative correlation between the SUVmax value and ADC value in the GPC-3 group (R=-0.279, P=0.006). The SUVmax value was strongly positively correlated with the Ki-67 expression index (R=0.733, P<0.001), while the ADC value was strongly negatively correlated with the Ki-67 expression index (R=-0.687, P<0.001).

Conclusion

DWI and 18F-FDG PET/CT can be used to evaluate the expression of Ki-67 and GPC-3 in HCC, and there is a certain correlation between the ADC value and SUVmax. Combined DWI and 18F-FDG PET/CT is superior to a single technique in evaluating the expression of GPC-3 in HCC patients. However, the combined model did not benefit the Ki-67 group.

The role of 18F-FDG PET/CT in diagnosis and treatment evaluation for ocular adnexal mucosa-associated lymphoid tissue lymphoma

OBJECTIVE

The purpose of this study is to evaluate the value of fluorine-18-fludeoxyglucose positron emission tomography (¹⁸F-FDG PET)/CT in the diagnosis and treatment evaluation of ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphoma.

METHODS

70 patients with OAML who received radiotherapy were recruited in our study. All the patients had the ¹⁸F-FDG PET/CT examination before the treatment. We retrospectively reviewed the medical records, pathological reports, laboratory results, and imaging features of all patients. The associations between ¹⁸F-FDG PET/CT parameters and Epstein-Barr virus antibodies, treatment response, MRI data, and Ki-67 expression were investigated.

RESULTS

The PET/CT scan indicated that 80% (56/70) of the patients showed orbital FDG avidity. The median level of maximum standardized uptake value (SUVmax) of the lesions was 4.65 ± 3.00 (range:1.2-13.5). 92.0% (46/50) of the mass-forming lesions showed ¹⁸F-FDG avidity, while only 50.0% (10/20) of the non-massive lesions had ¹⁸F-FDG avidity (χ² = 13.23, p=0.01). The SUVmax in orbit, conjunctiva, and lacrimal gland lymphoma were 5.6, 2.9, and 3.7, respectively. A significant difference was identified of SUVmax among the three locations' lymphoma using one-way ANOVA analysis (F = 5.039, p = 0.01). After completion of radiotherapy, the complete remission rate was achieved in 30.8% (4/13) of the patients without ¹⁸F-FDG avidity, and 70.4% (38/54) in cases with ¹⁸F-FDG avidity (χ² = 5.43, p = 0.02). The correlation between high Ki-67 score and ¹⁸F-FDG avidity was confirmed (χ² = 3.916, p = 0.048); however, no significant correlation was found between the SUVmax and Ki-67 score of the lesions (p = 0.971). Three patients (3/70, 4.3%) were upregulated the stage via PET/CT.

CONCLUSION

¹⁸F-FDG PET/CT had some potential values in the diagnosis and assessment of treatment response in patients with OAML.

ADVANCES IN KNOWLEDGE

The value of ¹⁸F-FDG PET/CT for patients with OAML.

Volumetric histograms-based analysis of apparent diffusion coefficients and standard uptake values for the assessment of pediatric sarcoma at staging: preliminary results of a PET/MRI study

PURPOSE

To assess the relationship between apparent diffusion coefficients (ADC) and standard uptake values (SUV) of pediatric sarcomas at staging by using volumetric histograms analyses.

METHODS

Children with histologically proven sarcoma, referring to our tertiary center for a whole-body ¹⁸F-FDG PET/MRI for staging and including diffusion weighted imaging in the MRI protocol were investigated. Firstly, turbo inversion recovery magnitude (TIRM) and PET images were resliced and resampled according to the ADC maps. Regions of interests were drawn along tumor margins on TIRM images and then copied on PET and ADC datasets. Pixel-based SUVs and ADCs were collected from the entire volume of each lesion. Mean, median, skewness, and kurtosis of SUVs and ADCs values were computed, and the Pearson correlation coefficient was then applied (for the entire population and for histological subgroups with more than five patients).

RESULTS

Thirteen patients met the inclusion criteria (six females; mean age 8.31 ± 6.03 years). Histology revealed nine rhabdomyosarcomas, three Ewing sarcomas, and one chondroblastic osteosarcoma. A significant negative correlation between ADCs' and SUVs' mean (r_mean = - 0.501, P < 0.001), median (r_median = - 0.519, P < 0,001), and skewness (r_skewness = - 0.550, P < 0.001) emerged for the entire population and for rhabdomyosarcomas (r_mean = - 0.541, P = 0.001, r_median = - 0.597, P < 0.001, r_skewness = - 0.568, P < 0.001), whereas a significant positive correlation was found for kurtosis (r_kurtosis = 0.346, P < 0.001, and r_kurtosis = 0.348, P < 0.001 for the entire population and for rhabdomyosarcomas, respectively).

CONCLUSION

Our preliminary results demonstrate that, using volumetric histograms, simultaneously collected SUVs and ADCs are dependent biomarkers in pediatric FDG-avid sarcomas. Further studies, on a larger population, are necessary to confirm this evidence and assess its clinical implications.

Does the SUVmax of FDG-PET/CT Correlate with the ADC Values of DWI in Musculoskeletal Malignancies?

Purpose

To evaluate the correlation of maximum standardized uptake values (SUV_max) of ¹⁸F-Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) with the apparent diffusion coefficient (ADC) of diffusion weighted imaging (DWI) in musculoskeletal malignancies.

Methods

Institutional ethics committee approved this retrospective study. Twenty-seven patients (mean age: 44.85 ± 24.07; 17 men and 10 women) with a total of 29 musculoskeletal tumors underwent both FDG-PET/CT and DWI between January 2017 and March 2020. Region-of-interest (ROI)-based maximal standardized uptake values (SUV_max) of the tumors were measured on FDG-PET/CT images. Two radiologists measured lesions' mean and minimum apparent diffusion coefficient (ADC_mean and ADC_min) using five distinct ROIs on DWI images. Pearson correlation analysis was used to assess the correlation between SUV_max and ADC values.

Results

There were 18 soft tissue tumors (62.1%) and 11 bone tumors (37.9%) with a mean maximum diameter of 9.4 ± 6.2 cm. The mean SUV_max, ADC_mean and ADC_min of the whole lesions were 12.93 ± 9.63, 0.85 ± 0.28 × 10^-3mm²/s and 0.61 ± 0.27 × 10^-3mm²/s, respectively. SUV_max had a weak correlation with tumor maximum diameter (r = 0.378, p = 0.043), whereas ADC_mean and ADC_min had none. There was strong inverse correlation between SUV_max and both ADC_mean (r = -0.616, p < 0.001) and ADC_min (r = -0.638, p < 0.001).

Conclusion

In musculoskeletal tumors, quantitative markers of FDG uptake and diffusion restriction strongly correlate.