The utility of 2-[18F]FDG-PET/CT maximum SUV versus CT attenuation for directing bone biopsies.

OBJECTIVES: This study aimed to compare the accuracy of PET/CT parameters with CT parameters for directing bone biopsies. METHODS: The study was an IRB-approved retrospective study of 388 patients who underwent both 2-[18F] FDG PET/CT and CT within 6 weeks before a bone biopsy. Age, sex, cancer type, lesion length, SUVmax, tumor to liver (T/L) ratio, CT attenuation, difference in CT attenuation between the lesion and normal bone (delta CT attenuation), and the absolute delta CT attenuation were used as predictors. T tests and chi-squared tests were used to compare variables. DeLong's test was used to compare receiver operator characteristic (ROC) curves. RESULTS: We reviewed the data from 388 patients. Of these, 295 patients had bone lesion biopsies, and 93 patients had bone marrow aspirations/biopsies. Biopsies of larger bone lesions (p = 0.033) and bone lesions with higher SUVmax (p = 0.005) were more likely to show malignancy. For bone lesions, the ROC curve for the SUVmax (AUC = 0.6827) was better than the ROC curves for delta CT attenuation (AUC = 0.5766, p = 0.032) and absolute delta CT attenuation (AUC = 0.5491, p = 0.006), but not significantly better than the ROC curves for CT attenuation (AUC = 0.5894, p = 0.061) and T/L ratio (AUC = 0.6778, p = 0.774). A threshold SUVmax of 5.25 had an accuracy of 0.713, sensitivity of 0.766, and specificity of 0.549 to predict malignancy in bone lesion biopsies. None of these variables predicted malignancy in bone marrow biopsies (p > 0.05 for all). CONCLUSIONS: Metabolic 2-[18F]FDG PET/CT parameters have more clinical impact for planning bone biopsies as compared to CT parameters. KEY POINTS: • The 2-[18F]FDG PET/CT measurement (SUVmax) has more clinical impact for planning bone biopsies as compared to CT measurements. • Neither the change in CT attenuation of the lesion relative to normal bone nor the absolute value of this change was a significant predictor of malignancy. • 2-[18F]FDG PET/CT may have clinical benefit and an additional role in directing bone biopsies.

Utility of absolute apparent diffusion coefficient and chemical-shift imaging versus CT attenuation for predicting malignancy from percutaneous bone biopsies.

INTRODUCTION: Bone lesions are sometimes detected on computed tomography studies, and biopsies are performed to evaluate whether these are malignant. The aim of the study is to evaluate whether chemical-shift imaging (CSI) and diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) are more informative than the CT attenuation for predicting malignancy. METHODS: Retrospective analysis of 86 patients who underwent both diagnostic CT, CSI MRI and DWI MRI within 6 weeks prior to bone biopsy at a tertiary care academic institution between 01/01/2010 and 03/01/2020. The CT attenuation, signal intensity on in-phase sequences (SIIP), signal intensity on out-of-phase sequences (SIOP), signal intensity ratio (SIR = SIOP/SIIP) and the apparent diffusion coefficient (ADC) of the lesions over the region of the biopsy tract were measured. RESULTS: A threshold CT attenuation of 157 Hounsfield Units (HU) had a sensitivity of 47.7%, specificity of 83.3% and area under the curve (AUC) of 0.59. A threshold ADC of 793 × 10-6 mm2 /s had a sensitivity of 75.8%, specificity of 85.7% and AUC of 0.83 to predict whether a bone biopsy would detect malignancy. A threshold SIR of 0.949 had a sensitivity of 77.8%, specificity of 77.8% and AUC of 0.81 to predict whether a bone biopsy would detect malignancy. ADC (P = 0.029) and SIR (P = 0.009) were significantly better than CT attenuation. There was no predictive difference between SIR and ADC (P = 0.742). CONCLUSIONS: The CT attenuation of a lesion is a poor predictor of malignancy in bone lesions. CSI and DWI are significantly better for predicting malignancy.

A Statistical Approach Regarding the Diagnosis of Osteoporosis and Osteopenia From DXA: Are We Underdiagnosing Osteoporosis?

Osteoporosis and osteopenia are diagnosed most commonly by evaluating the lowest T-score of BMD measurements, typically taken at three sites: the L1-L4 lumbar spine, femoral neck, and total hip. This study aimed to evaluate the effect of using all three BMD measurements and multivariate statistical theory to evaluate how the diagnoses of osteoporosis and osteopenia change in simulation studies and in real data. First, it was found that the T-scores from these three BMD measurements rarely give concordant diagnoses using the same World Health Organization (WHO) and International Society for Clinical Densitometry (ISCD) guidelines, so that the diagnosis strongly depends on the BMD sites measured. Next, strong correlations were found between the BMD measurements at different sites within the same person, which resulted in increased congruence/concordance between the diagnoses obtained from the BMD T-scores. Multivariate statistical theory was used to show that the joint distribution of the BMD T-scores at different sites follows a multivariate t distribution and found that the marginal distribution of any BMD T-score follows a univariate t distribution. Confidence ellipsoids were derived that are equivalent to the univariate WHO/ISCD thresholds for osteoporosis (T-score ≤-2.5) and osteopenia (-2.5 < T-score <-1). The study found that more patients are diagnosed with osteoporosis using the multivariate version of the WHO/ISCD guidelines rather than the current WHO/ISCD guidelines in both real data and simulation studies. Diagnoses of osteoporosis using the statistics derived method were also associated with higher FRAX (fracture risk assessment tool) probabilities of major osteoporotic (p = 0.001) and hip fractures (p = 2.2 × 10-6). In conclusion, this study shows that considering all three BMD T-scores is potentially more informative than using the single lowest BMD T-score. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Association between tears of the posterior root of the medial meniscus and far posterior femoral condyle osteoarthritis.

PURPOSE: We aimed to evaluate whether tears of the posterior horn of the medial meniscus root ligament (PHMM RL) are associated with osteoarthritis of the far posterior femoral condyles (FPFC). METHODS: Retrospective review of 1158 patients who underwent arthroscopy identified 49 patients with confirmed tears of the medial meniscus posterior root ligament attachment. Preoperative magnetic resonance imaging (MRI) studies were reviewed to identify advanced osteoarthritis involving the medial and lateral FPFC. Control patients (n=48) had no meniscal tears confirmed by arthroscopy. Cases and controls were age- and sex-matched exactly 1:1. One case patient was excluded since there was no age- and sex-matched control available. The International Cartilage Research Society (ICRS) MRI cartilage grade was recorded for the medial and lateral FPFC. Associations were evaluated using univariate and multivariable conditional logistic regression analyses. RESULTS: There were 48 case and 48 control patients (10 men in each group, 20.8%) with median age 53 years (range, 21-67). Medial FPFC ICRS Grade 2 or higher lesions were present in 34 (70.8%) of case patients and 16 (33.3%) of control patients. Lateral FPFC ICRS Grade 2 or higher lesions were present in 24 (50%) of case patients and 14 (28.2%) of control patients. Increased body mass index (BMI) was associated with PHMM RL tears (OR=1.11, 95% CI [1.01, 1.22], P = 0.020). MRI was 81.2% (39/48) sensitive and 91.2% (44/48) specific for detection of PHMM RL tears. PHMM RL tears were associated with Grade 2 or higher medial FPFC osteoarthritis (OR=10.00, 95% CI (2.34, 42.78), P < 0.001). This association remained after adjusting for BMI (OR=11.79, 95% CI [2.46, 56.53], P = 0.002). There was also an association between PHMM RL tears and lateral FPFC osteoarthritis, which persisted after adjusting for BMI (OR =3.00, 95% CI [1.07, 8.37], P = 0.036). CONCLUSION: PHMM RL tears are associated with advanced osteoarthritis of the FPFC. Radiologists identifying FPFC osteoarthritis should look carefully for PHMM RL tears.