Concordance between fine-needle aspiration and core biopsies for osseous lesions by lesion imaging appearance and CT attenuation. Radiol Med. 2018;123:254-259. [PMID: 29249078 DOI: 10.1007/s11547-017-0841-8]

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, SUV_max, 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 SUV_max (p = 0.005) were more likely to show malignancy. For bone lesions, the ROC curve for the SUV_max (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 SUV_max 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.

Fine-needle aspiration biopsy for the diagnosis of bone and soft tissue lesions: a systematic review and meta-analysis

INTRODUCTION

The workup of musculoskeletal (MSK) lesions utilizes a range of diagnostic tests including incisional biopsy, core needle biopsy, and fine-needle aspiration (FNA). FNA is the most cost-effective and least invasive biopsy method, but variation in its reported diagnostic performance has constrained its use for MSK lesions. Herein, we undertake a meta-analysis to clarify the diagnostic performance of FNA for bone and soft tissue lesions.

MATERIALS AND METHODS

A systematic search was run in MEDLINE, EMBASE, and CINAHL. Included studies were aggregated for pooled estimates of adequacy, accuracy, and sensitivity/specificity for all MSK lesions as well as bone and soft tissue independently. Analysis of heterogeneity and risk of bias were assessed across studies. Covariate subgroup analyses were attempted to investigate potential influences on diagnostic accuracy.

RESULTS

Twenty-five articles met inclusion criteria, representing 4604 FNAs. Adequacy was 92.3% (range: 59.2%-98.0%, S = 9.4%), and sensitivity/specificity for the nature (malignant or benign) of the lesion was 95.6% (95% CI: 94.5%-96.5%) and 96.9% (95% CI: 95.9%-97.7%). FNA was 75.8% accurate (range: 42.5%-99.3%, S = 17.3%) for definitive diagnosis. FNA provides higher accuracy for benign versus malignant nature in bone lesions but achieves a definitive diagnosis more frequently in soft tissue lesions.

CONCLUSIONS

The results of this meta-analysis support the expanded use of FNA in the diagnostic workup of bone and soft tissue lesions, particularly in light of a sensitivity and specificity comparable to incisional and core needle biopsy.

Predictors of positive bone cultures from CT-guided bone biopsies performed for suspected osteomyelitis

INTRODUCTION

Bone biopsies are often used to direct antibiotic choice in patients with suspected osteomyelitis. The aim of this study was to identify the best predictors of positive bone biopsy cultures.

METHODS

A retrospective review of 845 patients who underwent computed tomography (CT)-guided non-spine bone biopsies at a tertiary academic healthcare institution. Thirty-seven patients (4.4%) had biopsies performed for suspected osteomyelitis. Laboratory markers, as well as imaging features, were measured. t-Tests and Fisher's exact tests were used to compare clinical and demographic variables between patients with positive bone cultures and patients with negative bone cultures. Multivariable logistic regression was used to identify the best predictors of bone culture positivity.

RESULTS

All patients had negative blood cultures; however, only eight patients (21.6%) had positive bone cultures, with Staphyloccocus the most common organism. Multivariable logistic regression analysis showed that an open wound (OR = 14.00, 95% CI (1.74, 112.4), p = 0.013) and any fluid aspirated at the time of biopsy (OR = 10.50, 95% CI (1.21, 91.01), p = 0.033) were the best predictors of bone culture positivity. The area under the curve (AUC) for this multivariable model was 0.784 with sensitivity and specificity of 0.778 and 0.778, respectively. Interestingly, and contrary to popular belief, open wounds with exposed bone did not always yield positive bone cultures, and when cultures were positive, were not polymicrobial.

CONCLUSIONS

Aspiration of fluid at the time of biopsy and the presence of an open wound are the best predictors of positive bone cultures.

Positron emission tomography/computed tomography imaging appearance of benign and classic “do not touch” osseous lesions

BACKGROUND

Classic “do not touch” and benign osseous lesions are sometimes detected on ¹⁸-F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) studies. These lesions are often referred for biopsy because the physician interpreting the PET/CT may not be familiar with the spectrum of ¹⁸F-FDG uptake patterns that these lesions display.

AIM

To show that “do not touch” and benign osseous lesions can have increased ¹⁸F-FDG uptake above blood-pool on PET/CT; therefore, the CT appearance of these lesions should dictate management rather than the standardized uptake values (SUV).

METHODS

This retrospective study evaluated 287 independent patients with 287 classic “do not touch” (benign cystic lesions, insufficiency fractures, bone islands, bone infarcts) or benign osseous lesions (hemangiomas, enchondromas, osteochondromas, fibrous dysplasia, Paget’s disease, osteomyelitis) who underwent ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) at a tertiary academic healthcare institution between 01/01/2006 and 12/1/2018. The maximum and mean SUV, and the ratio of the maximum SUV to mean blood pool were calculated. Pearson’s correlations between lesion size and maximum SUV were calculated.

RESULTS

The ranges of the maximum SUV were as follows: For hemangiomas (0.95-2.99), bone infarcts (0.37-3.44), bone islands (0.26-3.29), enchondromas (0.46-2.69), fibrous dysplasia (0.78-18.63), osteochondromas (1.11-2.56), Paget’s disease of bone (0.93-5.65), insufficiency fractures (1.06-12.97) and for osteomyelitis (2.57-12.64). The range of the maximum SUV was lowest for osteochondromas (maximum SUV 2.56) and was highest for fibrous dysplasia (maximum SUV of 18.63). There was at least one lesion that demonstrated greater ¹⁸F-FDG avidity than the blood pool amongst each lesion type, with the highest maximum SUV ranging from 9.34 times blood pool mean (osteomyelitis) to 1.42 times blood pool mean (hemangiomas). There was no correlation between the maximum SUV and the lesion size except for enchondromas. Larger enchondromas had higher maximum SUV (r = 0.36, P = 0.02).

CONCLUSION

The classic “do not touch” lesions and classic benign lesions can be ¹⁸F-FDG avid. The CT appearance of these lesions should dictate clinical management rather than the maximum SUV.