Analysis of nondiagnostic results after image-guided needle biopsies of musculoskeletal lesions

Inferring malignancy grade of soft tissue sarcomas from magnetic resonance imaging features: A systematic review

PURPOSE

Systematic reviews on the grading of STS using MRI are lacking. This review analyses the role of different MRI features in inferring the histological grade of STS.

MATERIALS AND METHODS

A systematic review was conducted and is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The electronic databases of PubMed/MEDLINE were systematically searched for literature addressing the correlation of MRI findings in soft tissue sarcoma with tumor grade. As keywords "MRI", "magnetic resonance imaging", "sarcoma", "grade", "grading", and "FNCLCC" have been selected.

RESULTS

14 studies have been included in this systematic review. Tumor size (p = 0.015 (51 patients) to p = 0.81 (36 patients)), tumor margin (p < 0.001 (95 patients) to 0.93 (36 patients)), necrosis (p = 0.004 (50 patients) to p = 0.65 (95 patients)), peritumoral edema (p = 0.002 (130 patients) to p = 0.337 (40 patients)), contrast enhancement (p < 0.01 (50 patients) to 0.019 (51 patients)) and polycyclic/multilobulated tumor configuration (p = 0.008 (71 patients)) were significantly associated with STS malignancy grade in most of the included studies. Heterogeneity in T2w images (p = 0.003 (130 patients) to 0.202 (40 patients)), signal intensity in T1w images/ hemorrhage (p = 0.02 (130 patients) to 0.5 (31 patients)), peritumoral contrast enhancement (p < 0.001 (95 patients) to 0.253 (51 patients)) and tumoral diffusion restriction (p = 0.01 (51 patients) to 0.53 (52 patients)) were regarded as significantly associated with FNCLCC grade in some of the studies which investigated these features. Most other MRI features were not significant.

CONCLUSION

Several MRI features, such as tumor size, necrosis, peritumoral edema, peritumoral contrast enhancement, intratumoral contrast enhancement, and polycyclic/multilobulated tumor configuration may indicate the malignancy grade of STS. However, further studies are needed to gain consensus.

Ultrasound-guided core needle biopsy combined with immunohistochemistry and molecular testing improve the diagnostic accuracy of bone metastases from follicular thyroid carcinoma, two case reports and analyses

Key Clinical Message

Ultrasound-guided core needle biopsy combined with immunohistochemistry and molecular testing could improve the diagnostic accuracy of bone metastases from follicular thyroid carcinoma, help to predict distant metastasis and prognosis.

Abstract

Metastatic thyroid follicular carcinoma presenting initially with bone lesion is uncommon, its prime symptom is gradual onset, localized pain. Patient with bone metastasis who were diagnosed before thyroidectomy had a higher rate of mortality, clinician should be cautious in eliciting the clinical history and this insidious symptom in middle age group, carry out further examination. We are presenting two case reports of a follicular thyroid carcinoma with bone metastasis, ultrasound-guided core needle biopsy combined with immunohistochemistry (IHC) were carried out by our clinical team to determine the source and nature of the tumor, relevant literature was reviewed, molecular testing was discussed, we believe core needle biopsy combined with IHC and molecular testing improve the diagnostic accuracy of bone metastases from follicular thyroid carcinoma.

Diagnostic efficacy of image-guided core needle biopsy of suspected malignant osseous lesions: a retrospective cohort study from a single academic institution

OBJECTIVES

To evaluate diagnostic yield and accuracy of image-guided core needle biopsy (ICNB) of suspected malignant osseous lesions in a large cohort of adults, evaluate what factors influence these measures, and offer technical recommendations to optimize yield.

METHODS

A retrospective analysis of 2321 ICNBs performed from 2010 to 2021 was completed. The diagnostic yield and accuracy of the biopsies as well as a series of patient, lesion-related, and technical factors were retrospectively analyzed. Multivariate statistical analysis was performed to evaluate what factors were associated with yield and accuracy. Different cutoff values of total core length and core number were then tested to determine threshold values in relation to increased diagnostic yield.

RESULTS

Diagnostic yield was 98.2% (2279/2321) and accuracy was 97.6% (120/123). Increased total core length (odds ratio [OR] = 2.34, 95% confidence interval [CI] (1.41-3.90), p = 0.001), core number (OR = 1.51, 95% CI (1.06-2.16), p = 0.02) and presence of primary malignancy (OR = 2.81, 95% CI (1.40-5.62), p = 0.004) were associated with improved yield. Lesion location in an extremity (OR = 0.27, 95% CI (0.11-0.68), p = 0.006) and using fluoroscopic imaging guidance (OR = 0.33, 95% CI (0.12-0.90), p = 0.03) were associated with lower yield. Cutoff thresholds in relation to increased diagnostic yield were found to be 20 mm total core length (marginal OR = 4.16, 95% CI = (2.09-9.03), p < 0.001), and three total cores obtained (marginal OR = 2.78, 95% CI (1.34-6.54), p = 0.005). None of the analyzed factors influenced diagnostic accuracy.

CONCLUSIONS

ICNB has a high rate of diagnostic yield and accuracy. Several factors influence diagnostic yield; 20 mm core length and three total cores optimize yield.

CLINICAL RELEVANCE STATEMENT

Image-guided core needle biopsy of suspected malignant osseous lesions is a safe procedure with a very high rate of diagnostic yield and accuracy. Obtaining 20 mm total core length and three total cores optimizes diagnostic yield.

KEY POINTS

• In a retrospective cohort study, image-guided core needle biopsy of suspected osseous malignant lesions in adults was found to have very high rates of diagnostic yield and accuracy. • Increased total core length and core number of biopsies were each associated with increased diagnostic yield, and these relationships reached thresholds at 20 mm total core length and three total cores obtained. • The presence of a known primary malignancy was also associated with increased yield while using fluoroscopic imaging guidance and lesion location in an extremity were associated with decreased yield.

Diagnostic yield and concordance of image-guided biopsy in musculoskeletal lesions

OBJECTIVE

Image-guided biopsy is well-established in the diagnosis of musculoskeletal lesions. While several studies have demonstrated a high diagnostic yield in image-guided biopsy, there are no current guidelines around procedural factors such as number of cores. Furthermore, there have been mixed results regarding which lesions are more favourable to a diagnostic biopsy. We wanted to evaluate diagnostic yield and concordance for image-guided biopsies for musculoskeletal lesions. The null hypothesis was that there are no controllable factors that contribute to positive yield.

MATERIALS AND METHODS

Retrospective review of consecutive patients who underwent image-guided biopsy at a large teaching hospital for musculoskeletal lesions discussed at the sarcoma multi-disciplinary meeting. The formal biopsy histology report was evaluated, and biopsies were considered diagnostic or non-diagnostic. In those that had subsequent surgery (by wide excision or open biopsy), final and initial histology was compared and biopsies were considered concordant or not. Overall diagnostic yield and concordance were calculated. Statistical analysis was performed with Stata 13.0 (StataCorp).

RESULTS

Over the 14-year period, 429 biopsies were included. Diagnostic yield was 85% and concordance was 100%. No cases of malignant lesions were initially called benign on biopsy. One biopsy had a complication (0.2%). Factors associated with higher diagnostic yield included soft tissue versus bone lesions, three or more cores and longer total specimen length. Factors that were not associated included core size, use of FNA cytology, gender, age, benign versus malignant, anatomic location and lesion appearance.

CONCLUSION

The null hypothesis is rejected. The main predictor of diagnostic biopsy was total specimen length, independent of number of cores taken. Three or more cores and longer cores are optimal, though these factors are influenced by lesion biology and not always able to be controlled.

Prediction of histopathologic grades of myxofibrosarcoma with radiomics based on magnetic resonance imaging

PURPOSE

To develop a radiomics-based model from preoperative magnetic resonance imaging (MRI) for predicting the histopathological grades of myxofibrosarcoma.

METHODS

This retrospective study included 54 patients. The tumors were classified into high-grade and low-grade myxofibrosarcoma. The tumor size, signal intensity heterogeneity, margin, and surrounding tissue were evaluated on MRI. Using the least absolute shrinkage and selection operator (LASSO) algorithms, 1037 radiomics features were obtained from fat-suppressed T2-weighted images (T2WI), and a radiomics signature was established. Using multivariable logistic regression analysis, three models were built to predict the histopathologic grade of myxofibrosarcoma. A radiomics nomogram represents the integrative model. The three models' performance was evaluated using the receiver operating characteristics (ROC) and calibration curves.

RESULTS

The high-grade myxofibrosarcoma had greater depth (P = 0.027), more frequent heterogeneous signal intensity at T2WI (P = 0.015), and tail sign (P = 0.014) than the low-grade tumor. The area under curve (AUC) of these conventional MRI features models was 0.648, 0.656, and 0.668, respectively. Seven radiomic features were selected by LASSO to construct the radiomics signature model, with an AUC of 0.791. The AUC of the integrative model based on radiomics signature and conventional MRI features was 0.875. The integrative model's calibration curve and insignificant Hosmer-Lemeshow test statistic (P = 0.606) revealed good calibration.

CONCLUSION

An integrative model using radiomics signature and three conventional MRI features can preoperatively predict low- or high-grade myxofibrosarcoma.

Percutaneous CT-Guided Bone Biopsies: Indications, Feasibility and Diagnostic Yield in the Different Skeletal Sites-From the Skull to the Toe

CT-guided bone biopsies are currently the diagnostic tool of choice for histopathological (and microbiological) diagnoses of skeletal lesions. Several research works have well-demonstrated their safety and feasibility in almost all skeletal regions. This comprehensive review article aims at summarizing the general concepts in regard to bone biopsy procedures, current clinical indications, the feasibility and the diagnostic yield in different skeletal sites, particularly in the most delicate and difficult-to-reach ones. The choice of the correct imaging guidance and factors affecting the diagnostic rate, as well as possible complications, will also be discussed. Since the diagnostic yield, technical difficulties, and complications risk of a CT-guided bone biopsy significantly vary depending on the different skeletal sites, subdivided analyses of different anatomical sites are provided. The information included in the current review article may be useful for clinicians assisting patients with possible bone neoplasms, as well as radiologists involved in the imaging diagnoses of skeletal lesions and/or in performing bone biopsies.

The management of non-diagnostic soft tissue tumour biopsies using a multi-disciplinary team approach: A 10-year retrospective review at a specialist sarcoma unit

Non-Diagnostic (ND) biopsies are occasionally encountered during the investigation of soft tissue sarcoma. We performed a retrospective review of all ND soft tissue biopsies discussed at our regional Multi-Disciplinary Team (MDT) meeting between 2004 & 2014 with the aim of establishing the incidence of ND biopsies, identifying predictive factors for repeat biopsies and evaluating the effectiveness of MDT decisions. We identified 80 ND out of 3233 biopsies. Diagnostic Yield (DY) was 97.5%, 76.0% and 77.8% for the first, second and third successive biopsy respectively. With an MDT approach utilising radiological and clinical information, the diagnostic success rate achieved was 98.5%, 82.0% and 77.8% for the first, second and third biopsies respectively. Malignant tumours (sarcoma & carcinoma) were 19 times more likely to undergo an increasing number of biopsies compared to benign lesions (p < 0.01), while repeat biopsies were less useful for suspected benign lesion. Although a repeat biopsy was only performed in 63% of cases, there were no patients originally diagnosed with a benign lesion that re-presented with the same lesion subsequently being malignant throughout the study period. Our study shows that a specialist MDT approach leads to high diagnostic rates and is a safe and effective method of preventing unnecessary, repeat biopsies where the initial biopsy is ND.

Image-Guided Percutaneous Needle Biopsy for Benign and Malignant Bone Tumors: Systematic Review and Meta-Analysis

PURPOSE

To compare the diagnostic yield and accuracy of both image-guided core-needle biopsy (CNB) and fine-needle biopsy and evaluate the benefit of performing fine-needle biopsy in addition to CNB in patients with suspected benign and malignant bone tumors.

MATERIALS AND METHODS

A systematic search was performed on March 10, 2021, to determine whether fine-needle aspiration (FNA) plays any role when performed alone or in combination with CNB. The included studies were aggregated for the pooled estimates of diagnostic yield and histologic accuracy of image-guided percutaneous needle biopsy of bone tumors. Twenty-nine studies published between 1996 and 2021 were included.

RESULTS

When all patients with bone tumors were included, the rates of diagnostic yield and accuracy of FNA and CNB were 88.5% and 82.5% and 91.4% and 92.7%, respectively; the rates of both the methods combined were 96.5% and 94.1%, respectively; and for the lytic subgroup, the rates of diagnostic yield and accuracy of CNB and both the methods combined were 94.3% and 100% and 98.9% and 90.4%, respectively. A P value of <.05 was considered statistically significant.

CONCLUSION

The present meta-analysis showed that core biopsy alone outperformed fine-needle biopsy alone in all categories of benign and malignant tumors. Additionally, the diagnostic yield was improved when FNA was used in addition to CNB for lytic bone lesions.

Epithelioid Vascular Lesions: The Differential Diagnosis and Approach in Cytology and Small Biopsies

Vascular neoplasms are rare tumors with a multitude of clinical presentations and behavior, which make accurate identification and subclassification challenging on limited small biopsies. Within the spectrum of these lesions, the ones with epithelioid morphology, such as epithelioid hemangioendothelioma and epithelioid angiosarcoma, are particularly challenging given the morphologic overlap with nonvascular lesions and the limited cells due to hemodilution on sampling. Herein, we review the differential diagnosis of epithelioid vascular neoplasms, with a focus on the cytomorphology, differential diagnoses, and ancillary studies that pathologists should be aware of when evaluating small biopsies and aspirates, including novel translocations, and associated monoclonal immunohistochemistry antibodies, that can help in the diagnosis of some of these tumors. Awareness of these morphologic and ancillary study findings in these rare tumors will hopefully allow pathologists to recognize and render-specific diagnoses on limited samples of these challenging lesions.

Soft tissue sarcoma: intravoxel incoherent motion and diffusion kurtosis imaging parameters correlate with the histological grade and Ki-67 expression

BACKGROUND

Accurate prediction of the histological grade and Ki-67 expression of soft tissue sarcoma (STS) before surgery is essential for the subsequent diagnosis, treatment, and prognostic evaluation of patients.

PURPOSE

To evaluate intravoxel incoherent motion (IVIM) and diffusion kurtosis imaging (DKI) in predicting the histological grade and Ki-67 expression of STS.

MATERIAL AND METHODS

A total of 40 patients underwent 3-T MRI, including conventional sequences; IVIM and DKI parameters were obtained. All patients were divided into a low-grade (grade 1 and grade 2) group and a high-grade (grade 3) group through pathological analysis. Ki-67 expression of each lesion was calculated. Chi-square test, independent sample t-test, Mann-Whitney U test, Pearson, Spearman, and receiver operating characteristic curve analysis were performed.

RESULTS

There were 17 patients in the low-grade group and 23 in the high-grade group. Ki-67 expression was in the range of 10%-80%. D value was inversely correlated with Ki-67 expression. MK value showed a moderate positive correlation with Ki-67 expression. Regarding histological grading, only the peritumoral enhancement was statistically different between low- and high-grade STS on conventional MRI (P=0.024). The high-grade group had significantly higher MK value and lower D and MD value than the low-grade group. MK value showed the best diagnostic performance. The combination of MK and MD yielded the highest specificity (88.24%), and the combination of D, MK, and MD yielded the best area under the curve value (0.841) and sensitivity (95.65%).

CONCLUSION

IVIM and DKI parameters were correlated with Ki-67 expression and could help differentiate between low- and high-grade STS.

Analysis of Factors Potentially Influencing Diagnostic Yield Among Computed Tomography-Guided Biopsies for Bone Lesions

OBJECTIVE

This study aimed to investigate patient-specific, lesion-related, and technical factors that potentially influence diagnostic yield of computed tomography (CT)-guided biopsies of bone lesions.

METHODS

Computed tomography-guided bone lesion biopsies performed over a 2-year period were retrospectively reviewed, including image review and electronic medical records for pathology reports and clinical follow-up. Lesions were tabulated by prebiopsy CT and magnetic resonance imaging features. Patients with nondiagnostic biopsies were assessed for presumptive clinical diagnosis and management.

RESULTS

Nondiagnostic pathology results were obtained in 31 of 156 cases (19.87%), among which diagnoses were confirmed by other tissue sampling in 9; clinical follow-up of up to 2 years yielded no diagnosis in 10 and presumptive diagnoses in 12. The nondiagnostic biopsy rate of long bone lesions was higher than that of other bone lesions (odds ratio, 3.46; 95% confidence interval, 1.32-9.09). There were no significant differences in patient American Society of Anesthesiologists class, mean body mass index, sedation method, number of cores, or needle gauge between diagnostic and nondiagnostic biopsy cohorts. Diagnostic yield was not significantly different between occult, lytic, or sclerotic lesions. There was no difference in diagnostic yield regarding presence of cortical break, gadolinium enhancement, or lesion depth. Magnetic resonance imaging was obtained before biopsy in significantly more nondiagnostic cases compared with diagnostic cases (P = 0.027).

CONCLUSIONS

Computed tomography-guided biopsies had a nondiagnostic rate of 19.87%, and lesions in the long bones of the extremities were disproportionately common among this group. There was no significant association between biopsy results and several patient-specific, lesion-related, and technical factors.

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part II: Joint Pathologies, Pediatric Applications, and Guided Procedures

The second part of the Guidelines and Recommendations for Musculoskeletal Ultrasound (MSUS), produced under the auspices of EFSUMB, following the same methodology as for Part 1, provides information and recommendations on the use of this imaging modality for joint pathology, pediatric applications, and musculoskeletal ultrasound-guided procedures. Clinical application, practical points, limitations, and artifacts are described and discussed for every joint or procedure. The document is intended to guide clinical users in their daily practice.

A Multidisciplinary Team Approach Is Highly Effective in the Management of Nondiagnostic Bone Tumour Biopsies: A 10-Year Retrospective Review at a Specialist Sarcoma Unit

Nondiagnostic (ND) biopsies are frequently encountered during the investigation of bone tumours and can lead to treatment delay. We performed a retrospective review of all ND bone tumour biopsies discussed at our regional MDT meeting between 2004 and 2014 with the aim of establishing the incidence of ND biopsies, identifying any factors that could predict the requirement for repeat biopsies, and evaluating the effectiveness of multidisciplinary team (MDT) decisions. We identified 98 ND out of 4949 biopsies. Diagnostic yield (DY) was 98%, 76%, and 40% for the first, second, and third successive biopsy, respectively. With an MDT approach utilising radiological and clinical information, the diagnostic success rate achieved was 99%, 85%, and 80% for the first, second, and third biopsies, respectively. Although a repeat biopsy was only performed in 34% of cases, there were no patients originally diagnosed with a benign lesion that re-presented with the same lesion subsequently being malignant throughout the study period. Malignant primary bone tumours (p < 0.01) and malignant secondary tumours (p=0.02) were more likely to undergo repeat biopsy compared to benign and infective lesions. Upper limb (p=0.04) and lower limb (p=0.03) were more likely than pelvic and spinal tumours to undergo a repeat biopsy. Tumours of haematological origin frequently required multiple biopsies. Our study demonstrated that a specialist MDT approach leads to high diagnostic rates and is a safe and effective method of preventing unnecessary, repeat biopsies where the initial biopsy is ND.

Image-guided core needle biopsy for musculoskeletal lesions

BACKGROUND

Image-guided percutaneous core needle biopsy (CNB) has been an important diagnostic procedure for musculoskeletal lesions. Here we surveyed the variety of diagnostic strategies available and assessed the clinical usefulness and limitations of image-guided CNB carried out by a multidisciplinary team comprising specialists in various fields.

METHODS

We conducted a retrospective study of 284 image-guided CNBs among 1899 consecutive biopsy procedures carried out at our institution for musculoskeletal tumorous conditions, focusing on their effectiveness including diagnostic accuracy and utility for classification of specimens according to malignant potential and histological subtype as well as their correlation with biopsy routes.

RESULTS

Among the 284 studied biopsies, 252 (88.7%) were considered clinically "effective". The sensitivity for detection of malignancy was 94.0% (110/117) and the specificity was 95.3% (41/43). The diagnostic accuracy for detection of malignancy was 94.4% (151/160) and that for histological subtype was 92.3% (48/52). The clinical effectiveness of the procedure was correlated with the complexity of the biopsy route (P = 0.015); the trans-pedicular, trans-retroperitoneal and trans-sciatic foramen approaches tended to yield ineffective results. Repeat biopsy did not have a significant impact on the effectiveness of image-guided CNB (P = 0.536).

CONCLUSIONS

The diagnostic accuracy rates of image-guided CNB performed at multidisciplinary sarcoma units were usable even for patients who have variety of diagnostic biopsy procedures. It is important to establish and implement diagnostic strategies based on an understanding that complicated routes, especially for spine and pelvic lesions, may be associated with ineffectiveness and/or complications.

Sarcomas of the extremities and the pelvis: comparing local recurrence after incisional and after core-needle biopsy

Background

The degree of contamination of healthy tissue with tumor cells during a biopsy in bone or soft tissue sarcomas is clearly dependant on the type of biopsy. Some studies have confirmed a clinically relevant contamination of the biopsy tract after incisional biopsies, as opposed to core-needle biopsies. The aim of our prospective study was to evaluate the risk of local recurrence depending on the biopsy type in extremity and pelvis sarcomas.

Methods

We included 162 patients with a minimum follow-up of 6 months after wide resection of extremity sarcomas. All diagnostic and therapeutic procedures were performed at a single, dedicated sarcoma center. The excision of the biopsy tract after an incisional biopsy was performed as a standard with all tumor resections. All patients received their follow-up after the conclusion of therapy at our center by means of regional MRI studies and, at a minimum, CT of the thorax to rule out pulmonary metastatic disease. The aim of the study was the evaluation of the influence of the biopsy type and of several other clinical factors on the rate of local recurrence and on the time of local recurrence-free survival.

Results

One hundred sixty-two patients with bone or soft tissue tumors of the extremities and the pelvis underwent either an incisional or a core-needle biopsy of their tumor, with 70 sarcomas (43.2%) being located in the bone. 84.6% of all biopsies were performed as core-needle biopsies. The median follow-up time was 55.6 months, and 22 patients (13.6%) developed a local recurrence after a median time of 22.4 months. There were no significant differences between incisional and core-needle biopsy regarding the risk of local recurrence in our subgroup analysis with differentiation by kind of tissue, grading of the sarcoma, and perioperative multimodal therapy.

Conclusions

In a large and homogenous cohort of extremity and pelvic sarcomas, we did not find significant differences between the groups of incisional and core-needle biopsy regarding the risk of local recurrence. The excision of the biopsy tract after incisional biopsy in the context of the definitive tumor resection seems to be the decisive factor for this result.

What morphological MRI features enable differentiation of low-grade from high-grade soft tissue sarcoma?

Objective:

To assess the diagnostic performance of morphological MRI features separately and in combination for distinguishing low- from high-grade soft tissue sarcoma (STS).

Methods and materials:

We retrospectively analysed pre-treatment MRI examinations with T1, T2 with and without fat suppression (FS) and contrast-enhanced T1 obtained in 64 patients with STS categorized histologically as low (n = 21) versus high grade (n = 43). Two musculoskeletal radiologists blinded to histology evaluated MRI features. Diagnostic performance was calculated for each reader and for MRI features showing significant association with histology (p < 0.05). Logistic regression analysis was performed to develop a diagnostic model to identify high-grade STS.

Results:

Among all evaluated MRI features, only six features had adequate interobserver reproducibility (kappa>0.5). Multivariate logistic regression analysis revealed a significant association with tumour grade for lesion heterogeneity on FS images, intratumoural enhancement≥51% of tumour volume and peritumoural enhancement for both readers (p < 0.05). For both readers, the presence of each of the three features yielded odds ratios for high grade versus low grade from 4.4 to 9.1 (p < 0.05). The sum of the positive features for each reader independent of reader expertise yielded areas under the curve (AUCs) > 0.8. The presence of ≥2 positive features indicated a high risk for high-grade sarcoma, whereas ≤1 positive feature indicated a low-to-moderate risk

Conclusion:

A diagnostic MRI score based on tumour heterogeneity, intratumoural and peritumoural enhancement enables identification of lesions that are likely to be high-grade as opposed to low-grade STS.

Advances in knowledge:

Tumour heterogeneity in Fat Suppression sequence, intratumoural and peritumoural enhancement is identified as signs of high-grade sarcoma.

Concepts in Musculoskeletal Bone and Soft Tissue Biopsy

Imaging-guided needle biopsy of musculoskeletal lesions is a high-yield and low-risk procedure that can be used for definitive characterization of indeterminate bone and soft tissue lesions. Familiarity with the preprocedural, technical, and postprocedural steps is vital for the appropriate management of these cases. Biopsy request triage requires an awareness of definitively benign conditions and other tumor mimics. A complete clinical, laboratory, and imaging work-up is essential for procedural planning and determining pathologic concordance. Consultation with an orthopaedic oncologist is a requisite step to ensure maximizing biopsy yield and to avoid interference with any future limb-sparing surgical intervention. Knowledge of the equipment, pertinent medications, and appropriate biopsy technique can minimize the risk of periprocedural complications. Finally, the radiologist may be required to discuss the concordance of histopathology with preprocedure imaging, perform repeat image-guided biopsy, and carefully interpret sarcoma surveillance imaging examinations.

Percutaneous Image-guided Needle Biopsy of Musculoskeletal Tumors: Technical Tips

With recent advances in imaging technology, the frequency of detecting musculoskeletal lesions has also increased. Percutaneous image-guided needle biopsy is occasionally required for the diagnosis of such lesions. Moreover, in the era of personalized cancer care, chances in histopathological diagnosis and the importance of histopathological diagnosis by percutaneous needle biopsy are increasing. However, as percutaneous needle biopsy is not a common procedure for musculoskeletal lesions, careful planning and the application of adequate techniques such as hydrodissection and the trans-osseous approach are occasionally required. In this review, we have summarized the indications and techniques for percutaneous image-guided needle biopsy for musculoskeletal lesions, including lymphatic lesions.

An Update in Imaging Evaluation of Histopathological Grade of Soft Tissue Sarcomas Using Structural and Quantitative Imaging and Radiomics

Over the past two decades, considerable efforts have been made to develop non-invasive methods for determining tumor grade or surrogates for predicting the biological behavior, aiding early treatment decisions, and providing prognostic information. The development of new imaging tools, such as diffusion-weighted imaging, diffusion kurtosis imaging, perfusion imaging, and magnetic resonance spectroscopy have provided leverage in the diagnosis of soft tissue sarcomas. Artificial intelligence is a new technology used to study and simulate human thinking and abilities, which can extract and analyze advanced and quantitative image features from medical images with high throughput for an in-depth characterization of the spatial heterogeneity of tumor tissues. This article reviews the current imaging modalities used to predict the histopathological grade of soft tissue sarcomas and highlights the advantages and limitations of each modality. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 2.

Percutaneous Core Needle Biopsy Can Efficiently and Safely Diagnose Most Primary Bone Tumors

A biopsy is a prerequisite for the diagnosis and evaluation of musculoskeletal tumors. It is considered that surgical biopsy provides a more reliable diagnosis because it can obtain more tumor material for pathological analysis. However, it is often associated with a significant complication rate. Imaging-guided percutaneous core needle biopsy (PCNB) is now widely used as an alternative to surgical biopsy; it appears to be minimally invasive, possibly with lower complication rates. This study evaluates the diagnostic yield of the preferred use of PCNB in a referral center, its accuracy, and its complication rate. The data relating to the biopsy and the histological analysis were extracted from the database of a bone tumor reference center where PCNB of bone tumors was discussed as a first-line option. 196 bone tumors were biopsied percutaneously between 2016 and 2020. They were located in the axial skeleton in 21.4% (42) of cases, in the lower limb in 58.7% (115), and in the upper limb in 19.9% (39) cases. We obtained a diagnosis yield of 84.7% and a diagnosis accuracy of 91.7%. The overall complication rate of the percutaneous biopsies observed was 1.0% (n = 2), consisting of two hematomas. PCNB performed in a referral center is a safe, precise procedure, with a very low complication rate, and which avoids the need for first-line open surgical biopsy. The consultation between pathologist, radiologist, and clinician in an expert reference center makes this technique an effective choice as a first-line diagnosis tool.

Adjunct diagnostic strategies in improving diagnostic yields in image-guided biopsies of musculoskeletal neoplasms-A cost-effectiveness analysis

BACKGROUND

Routine use of adjunct intraprocedural fresh frozen biopsy (FFP) or point-of-care (POC) cytology at the time of image-guided biopsy can improve diagnostic tissue yields for musculoskeletal neoplasms, but these are associated with increased costs.

OBJECTIVE

This study aimed to ascertain the most cost-effective adjunctive test for image-guided biopsies of musculoskeletal neoplasms.

METHODS

This expected value cost-effectiveness microsimulation compared the payoffs of cost (2020 United States dollars) and effectiveness (quality-adjusted life, in days) on each of the competing strategies. A literature review and institutional data were used to ascertain probabilities, diagnostic yields, utility values, and direct medical costs associated with each strategy. Payer and societal perspectives are presented. One- and two-way sensitivity analyses evaluated model uncertainties.

RESULTS

The total cost and effectiveness for each of the strategies were $1248.98, $1414.09, $1980.53, and 80.31, 79.74, 79.69 days for the use of FFP, permanent pathology only, and POC cytology, respectively. The use of FFP dominated the competing strategies. Sensitivity analyses revealed FFP as the most cost-effective across all clinically plausible values.

CONCLUSIONS

Adjunct FFP is most cost-effective in improving the diagnostic yield of image-guided biopsies for musculoskeletal neoplasms. These findings are robust to sensitivity analyses using clinically plausible probabilities.

Radiology-pathology correlation for bone and soft tissue tumors or tumor-like masses: single institutional experience after implementation of a weekly conference

OBJECTIVES

To determine the frequency of non-diagnostic and discordant results from bone and soft tissue biopsies performed at our institution over a 3-year period and to investigate whether implementation of a weekly musculoskeletal radiology-pathology correlation conference decreased the time to appropriate patient management in cases of discordance.

METHODS

Consecutive image-guided core needle biopsy results obtained over a 12 month period of time were reviewed in a retrospective fashion. Following implementation of the correlation conference, subsequent consecutive image-guided core needle biopsy results obtained over a 26 month period of time were reviewed in a prospective fashion. For non-diagnostic and discordant cases, the time in days from date of availability of the biopsy result to date of documentation of a specific follow-up action plan was recorded.

RESULTS

Diagnostic yield was 96.5% and 94.9% for the retrospective and prospective periods, respectively. There were four discordant results in the retrospective cohort (1.7%) and seven discordant results in the prospective cohort (2.1%). Following implementation of the weekly correlation conference, there was significant decrease (p < 0.05) in median time from a discordant biopsy result to follow-up action plan. There were no unnecessary surgeries, litigation, or other unfavorable consequences in either cohort.

CONCLUSION

Image-guided core needle biopsies of bone and soft tissue provide high diagnostic yield, often with specific diagnoses. The statistically significant decrease in number of days to follow-up action plan for discordant results suggests radiology-pathology review has a positive impact on patient care. Subjective benefits from communication and educational standpoints are also noteworthy.

Relative Sensitivity of Core-Needle Biopsy and Incisional Biopsy in the Diagnosis of Musculoskeletal Sarcomas

BACKGROUND

There is no evidence as to the diagnostic value of the two most frequently used methods of biopsies in sarcomas: Incisional or core needle biopsy. The aim of our study was to evaluate the diagnostic sensitivity of the incisional and the core needle biopsy techniques in the diagnosis of bone and soft tissue sarcomas.

METHODS

We included 417 patients with a definitive diagnosis of bone or soft tissue sarcoma in whom a total of 472 biopsies had been performed. We correlated the results of the biopsies with the result of the definitive histopathological examination of the resected tumor. Dignity, entity, and grading (whenever possible) of the tissue samples were evaluated.

RESULTS

A total of 258 biopsies (55%) were performed in order to diagnose a soft tissue tumor and 351 biopsies (74.4%) were core needle biopsies. The number of repeat core needle biopsies, necessitated because of inconclusive histopathological results, was significantly higher (50 vs. 5; p = 0.003). We observed no significant difference regarding dignity, entity, and grading between the 2 different types of biopsies. Only with regards to the determination of dignity and entity of chondroid tumors, incisional biopsy was superior with statistical significance (p = 0.024).

CONCLUSIONS

This study represents the largest study on biopsies for bone and soft tissue sarcomas. Based only on our results, we are unable to favor one method of biopsy and found high accuracy with both methods. Considering the potential complications, the added oncological risks of incisional biopsies and the ready availability of core needle biopsies, the latter, in our assessment, represents a valid and favourable method for bone and soft tissue sarcomas.

Percutaneous image-guided sternal biopsy: a cross-institutional retrospective review of diagnostic yield and safety in 50 cases

OBJECTIVE

Image-guided sternal biopsy may be technically daunting given the immediately subjacent critical structures. There is a paucity of literature describing technique, safety, and efficacy. This study aims to quantify the diagnostic yield and safety of image-guided sternal biopsies. Secondary aims include (1) describing the preferred approach/technique and (2) identifying imaging features and disease entities associated with higher and lower diagnostic yields.

MATERIALS AND METHODS

A retrospective review of 50 image-guided sternal biopsies performed at two quaternary care centers from 2000 to 2019 was performed. Recorded lesion-related variables included as follows: location, density, extraosseous extension, and size. Recorded variables from electronic medical records included as follows: patient demographics, histologic or microbiological diagnosis, and complications. Recorded technique-related variables included as follows: needle obliquity, type, and gauge; biopsy core number and length; and modality.

RESULTS

Of the 50 biopsies, 88.0% resulted in a definitive histologic diagnosis. Six biopsies were non-diagnostic. The majority of biopsies were performed under computed tomography (88.0%), followed by ultrasound (12.0%). Tumor was the most common biopsy indication (90.0%), followed by infection (10.0%). Of the diagnostic biopsies indicated for tumor, 88.9% were malignant. Seventy-four percent of the lesions were predominantly lytic. Fifty percent of lesions had extraosseous extension. Lesion locations were as follows: manubrium (48.0%), sternal body (48.0%), and sternomanubrial joint (4.0%). No minor or major, acute, or delayed procedure-related complications were encountered.

CONCLUSION

Image-guided sternal biopsy is an efficacious and safe method of obtaining a definitive histologic diagnosis regardless of lesion-specific features or location.

Pearls and Pitfalls for Soft-Tissue and Bone Biopsies: A Cross-Institutional Review

Management of soft-tissue and bone neoplasms depends on a definitive histologic diagnosis. Percutaneous image-guided biopsy of bone and soft-tissue tumors is a cost-effective and accurate method to obtain a histopathologic diagnosis. Biopsy requests must be approached thoughtfully to avoid numerous potential pitfalls. Hasty biopsy planning places the patient at increased risk for misdiagnosis, delayed therapy, repeated invasive procedures, and substantial morbidity. Biopsy planning begins with a thorough review of the relevant clinical history and pertinent imaging. The biopsy route must be planned in concert with the referring orthopedic oncologist to preserve limb-sparing options. Carefully selecting the most appropriate imaging modality to guide the biopsy increases the chances of reaching a definitive diagnosis. It is also critical to identify and target with expertise the part of the lesion that is most likely to yield an accurate diagnosis. Percutaneous biopsy is a safe procedure, and familiarity with preprocedural laboratory testing parameters, anticoagulation guidelines, and commonly used sedation medications minimizes the risk of complications while ensuring patient comfort. Nondiagnostic biopsy results are not infrequent and may still have value in guiding patient treatment. Awareness of the imaging manifestations of tumor recurrence is also important. The aim of this article is to provide a comprehensive review of pertinent preprocedural, periprocedural, and postprocedural considerations for bone and soft-tissue musculoskeletal biopsies.The online slide presentation from the RSNA Annual Meeting is available for this article.^©RSNA, 2020.

Configuration of soft-tissue sarcoma on MRI correlates with grade of malignancy

Background

The aim of the study was to assess whether the configuration of primary soft-tissue sarcoma (STS) on MRI correlates with the grade of malignancy.

Patients and methods

71 patients with histologically proven STS were included. Primary STS were examined for configuration, borders, and volume on MRI. The tumors were divided into high-grade (G3), intermediate-grade (G2) and low-grade (G1) STS according to the grading system of the French Federation of Cancer Centers Sarcoma Group (FNCLCC).

Results

30 high-grade, 22 intermediate-grade and 19 low-grade primary STS lesions were identified. High- and intermediate-grade (G3/2) STS significantly most often appeared as polycyclic/multilobulated tumors (p < 0.001 and p = 0.002, respectively). Low-grade (G1) STS mainly showed an ovoid/nodular or streaky configuration (p = 0.008), and well-defined borders. The appearance of high-, intermediate- and low-grade STS with an ovoid/nodular configuration were mainly the same on MRI. All streaky G3/2 sarcoma and 17 of 20 patients with polycyclic/multilobulated G3 sarcoma showed infiltrative borders. High-grade streaky and polycyclic/multilobulated STS are larger in volume, compared to intermediate- and low-grade STS.

Conclusions

Configuration of STS on MRI can indicate the grade of malignancy. Higher-grade (G2/3) STS most often show a polycyclic/multilobulated configuration, while low-grade STS are mainly ovoid/nodular or streaky. Infiltrative behavior might suggest higher-grade STS in streaky and polycyclic/multilobulated STS.

Percutaneous Imaging-Guided versus Open Musculoskeletal Biopsy: Concepts and Controversies

Bone and soft tissue tumors are a largely heterogeneous group of tumors. Biopsy of musculoskeletal (MSK) tumors is sometimes a challenging procedure. Although the open biopsy is still considered the gold standard for the biopsy of MSK lesions, core needle biopsy can replace it in most cases, with similar accuracy and a low complication rate. The biopsy should be performed in a tertiary sarcoma center where the multidisciplinary team consists of at minimum a tumor surgeon, an MSK pathologist, and an MSK radiologist who can assess all steps of the procedure. Several factors can influence the success of the biopsy including the lesion characteristics, the equipment, and the method used for the procedure. This review highlights some of the important aspects regarding the biopsy of the MSK tumors, with special attention to imaging a guided core needle biopsy and highlighting some of the recent advancements and controversies in the field.

Diagnostic accuracies of intraoperative frozen section and permanent section examinations for histological grades during open biopsy of bone tumors

BACKGROUND

A histological diagnosis obtained from an intraoperative frozen section (FS) during biopsy confirms the adequacy of tumor tissue in the specimen. However, some cases show a discrepancy among the intraoperative FS diagnosis, permanent section (PS) diagnosis of the biopsy specimen, and the final diagnosis of the excised tumor specimen. In this study, we retrospectively investigated the diagnostic accuracy of the FS and PS for different types of bone tumors.

METHODS

This study included 377 patients with 411 bone tumors who underwent tumor excision after an open biopsy with intraoperative FS diagnosis. FS, PS, and final diagnoses of the patients were classified into benign tumors/tumor-like lesions, intermediate malignancies, and malignant tumors. To assess diagnostic accuracy, the histological grades in FS and PS diagnoses were compared with those in the final diagnoses.

RESULTS

The overall diagnostic accuracies of FS and PS were 93% and 97%, respectively. The accuracy of FS and PS for histological grade was 84% and 93% for chondrogenic tumors, 90% and 96% for osteogenic tumors, 97% and 98% for osteoclastic giant cell-rich tumors, 100% and 100% for tumors of undefined neoplastic nature, and 95% and 99% for other bone tumors, respectively.

CONCLUSION

These data suggest that surgical planning based on PS diagnosis is recommended for chondrogenic and osteogenic tumors.

Soft tissue sarcoma: can dynamic contrast-enhanced (DCE) MRI be used to predict the histological grade?

OBJECTIVE

To determine if dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters reflect histological grade of soft tissue sarcoma (STS) MATERIALS AND METHODS: The medical records of 50 patients diagnosed with pathologically confirmed STS were retrospectively reviewed. Each STS was assessed with conventional contrast-enhanced MRI and DCE-MRI using a 3.0-T MRI system. The conventional MRI characteristics of low-grade (grade 1) and high-grade (grade 2 and grade 3) tumors were analyzed. Semi-quantitative parameters, including iAUC and TTP, and quantitative parameters, including K^trans, K_ep, and V_e, were derived from DCE-MRI. The diagnostic performances and optimal thresholds of various combinations of DCE-MRI parameters for predicting histological grades of STS were investigated using receiver operator characteristic (ROC) curves.

RESULTS

On conventional MRI, high-grade STSs were significantly larger (≥ 5 cm) and more likely to show a heterogeneous signal intensity on T₂WI (> 75%), peritumoral hyperintensity on T₂WI, or tumor necrosis (> 50%) compared with low-grade STS. On DCE-MRI, iAUC, TTP, K^trans, and K_ep were significant predictors of STS histological grade. K^trans had a high diagnostic value for differentiating between high-grade and low-grade STSs. The combination of iAUC, TTP, and K^trans yielded a higher AUC value (0.841) than the other models.

CONCLUSION

High-grade STSs were usually larger than low-grade STSs, had unclear boundaries, a heterogeneous signal intensity on T2-weighted image (T₂WI), and extensive necrosis. On DCE-MRI, iAUC, TTP, K^trans, and K_ep could differentiate between high-grade and low-grade STSs. The combination of iAUC, TTP, and K^trans had a high diagnostic performance for differentiating between STS histological grades.

Managing NON-DIAGNOSTIC biopsies in musculoskeletal tumours in a specialist centre: Deciding on the algorithm

INTRODUCTION

Core needle biopsy is an effective method of obtaining tissue diagnosis. However, a diagnostic dilemma arises when lesional tissue is non-diagnostic which obviates considering radiological guided re-biopsy (RB) or an open surgical biopsy but the question raised is which serves as a better diagnostic tool.

PATIENT AND METHODS

We retrospectively reviewed data from a prospectively collected database of 4516 core needle biopsies performed in our specialist musculoskeletal tumour centre over a 6-year period. Our aim was to evaluate the management of non-diagnostic biopsies (NDB) and establish a safe and accurate diagnostic strategy in the presence of a NDB.

RESULTS

Two hundred fifteen (4.8%) NDB cases with complete follow-up were identified. Of these 157 (73%) were treated definitively on the basis of imaging and 58 (27%) had a RB, 48 (83%) of which led to a positive histological diagnosis. The remaining 10 were again non-diagnostic giving a total of 167 patients being treated definitively without a tissue diagnosis. The sensitivity and specificity for multidisciplinary team (MDT) assessment as a diagnostic tool was 0.75 and 0.88 respectively while that for RB was 0.91 and 0.9.

CONCLUSION

Re-biopsy after first non-diagnostic core needle biopsy offers high sensitivity and specificity, especially in the presence of malignancy. In the absence of tissue diagnosis, however, MDT assessment is also highly accurate and a safe strategy in managing this complex group of patients.

LEVEL OF EVIDENCE

Diagnostic Level III.

Multidisciplinary approach for repeat musculoskeletal lesion biopsy after nondiagnostic initial sampling: A 10-year single-center experience

BACKGROUND AND OBJECTIVES

Success rates for initial image-guided biopsy of musculoskeletal (MSK) lesions have been well documented; evidence regarding success rates for repeat biopsy following initially nondiagnostic (ND) image-guided biopsy of MSK lesions is more limited. This study evaluates the outcomes of repeat computerized tomography-guided MSK biopsies following ND biopsies using a multidisciplinary approach.

MATERIALS AND METHODS

Electronic medical record search covering a 10-year period identified patients that received two or more biopsies for an MSK tumor or tumor-like process. The decision for initial and repeat image-guided biopsy of each lesion was made following multidisciplinary MSK tumor board review. Lesion location, histopathology results, size of biopsy needle when available, and change in technique between biopsy attempts was documented.

RESULTS

Repeat biopsy rate was 1.6%. 23 patients with repeat MSK biopsy were identified. A total of 17 of 23 (74%) repeat biopsy attempts were diagnostic. A total of 22 of 23 (96%) repeat biopsy attempts were clinically useful. Diagnostic repeat biopsies were described as employing one or more of five technical differences compared to the first biopsy attempt, the most common being improved targeting of the lesion itself.

CONCLUSIONS

A multidisciplinary approach may yield improved repeat-biopsy rates and clinical utility of repeat MSK biopsies compared to prior reports.

Tumor grade in soft-tissue sarcoma: Prediction with magnetic resonance imaging texture analysis

To determine the value of 3T magnetic resonance imaging (MRI) texture analysis in differentiating high- from low-grade soft-tissue sarcoma.Forty-two patients with soft-tissue sarcomas who underwent 3T MRI were analyzed. Qualitative and texture analysis were performed on T1-, T2- and fat-suppressed contrast-enhanced (CE) T1-weighted images. Various features of qualitative and texture analysis were compared between high- and low-grade sarcoma. Areas under the receiver operating characteristic curves (AUC) were calculated for texture features. Multivariate logistic regression analysis was used to analyze the value of qualitative and texture analysis.There were 11 low- and 31 high-grade sarcomas. Among qualitative features, signal intensity on T1-weighted images, tumor margin on T2-weighted images, tumor margin on fat-suppressed CE T1-weighted images and peritumoral enhancement were significantly different between high- and low-grade sarcomas. Among texture features, T2 mean, T1 SD, CE T1 skewness, CE T1 mean, CE T1 difference variance and CE T1 contrast were significantly different between high- and low-grade sarcomas. The AUCs of the above texture features were > 0.7: T2 mean, .710 (95% confidence interval [CI] .543-.876); CE T1 mean, .768 (.590-.947); T1 SD, .730 (.554-.906); CE T1 skewness, .751 (.586-.916); CE T1 difference variance, .721 (.536-.907); and CE T1 contrast, .727 (.530-.924). The multivariate logistic regression model of both qualitative and texture features had numerically higher AUC than those of only qualitative or texture features.Texture analysis at 3T MRI may provide additional diagnostic value to the qualitative MRI imaging features for the differentiation of high- and low-grade sarcomas.

Role of fine needle aspiration cytology in the diagnosis of soft tissue tumours

Fine needle aspiration cytology (FNAC) is a widely accepted safe, simple and rapid diagnostic procedure used in the examination of neoplastic and non-neoplastic lesions of various locations. Since its introduction, FNAC has developed into an effective diagnostic tool practiced in a large majority of medical centres evaluating and treating oncological patients. The role of FNAC has been limited in the examination of primary soft tissue lesions, however, as many physicians working in this area recommended against using FNAC. An increasing use of minimally invasive diagnostic procedures in the last decade has resulted in a better acceptance of FNAC as a first-line approach or as a complementary tool to core needle biopsy in the diagnosis of musculoskeletal lesions. This review discusses the role and value of FNAC in the evaluation and treatment of soft tissue tumours based on the experience gathered over the course of 48 years at the Sarcoma Center in Lund, Sweden. FNAC reports most often provide diagnostic information allowing the initiation of treatment or, when definitive diagnosis cannot be rendered from a cytological examination, guiding the continued diagnostic investigation. The main advantages of soft tissue FNAC are good sensitivity and specificity, low morbidity, speed of diagnosis, and low cost/benefit ratio. The most important disadvantages stem from limited experience in cytological diagnosis of soft tissue tumours and a lack of standardised and uniform reporting system for soft tissue FNAC.

Impact of the COVID-19 pandemic on patients suffering from musculoskeletal tumours

BACKGROUND

The aim of the current study was to evaluate the impact of the coronavirus disease (COVID-19) pandemic on musculoskeletal tumor service by conducting an online survey of physicians.

METHODS

The survey was conducted among the members of the ISOLS (International Society of Limb Salvage) and the EMSOS (European Musculo-Skeletal Oncology Society). The survey consisted of 20 questions (single, multiple-response, ranked): origin and surgical experience of the participant (four questions), potential disruption of healthcare (12 questions), and influence of the COVID-19 pandemic on the particular physician (four questions). A matrix with four different response options was created for the particular surgical procedures).

RESULTS

One hundred forty-nine physicians from five continents completed the survey. Of the respondents, 20.1% and 20.7% stated that surgery for life-threatening sarcomas were stopped or delayed, respectively. Even when the malignancy was expected to involve infiltration of a neurovascular bundle or fracture of a bone, still 13.8% and 14.7% of the respondents, respectively, stated that surgery was not performed. In cases of pending fractures of bone tumors, 37.5 to 46.2% of operations were canceled.

CONCLUSION

The SARS-CoV-2 pandemic caused a significant reduction in healthcare (surgery, radiotherapy, chemotherapy) for malignancies of the musculoskeletal system. Delaying or stopping these treatments is life-threatening or can cause severe morbidity, pain, and loss of function. Although the coronavirus disease causes severe medical complications, serious collateral damage including death due to delayed or untreated sarcomas should be avoided.

Lipomatous Soft Tissue Masses: Challenging the Paradigm of Routine Preoperative Biopsy

BACKGROUND

Lipomatous masses are the most common soft tissue tumors. While the majority are benign lipomas, it is important to identify those masses that are malignant prior to excision. Current guidelines recommend core needle biopsy (CNB) for all lipomatous masses larger than 3-5 cm. The objective of this study was to determine if routine preoperative CNB based on mass size is necessary, or if radiographic features can guide the need for CNB.

MATERIALS AND METHODS

Patients who underwent excision of extremity or truncal lipomatous masses at a single institution from October 2014 to July 2017 were retrospectively reviewed. By protocol, preoperative imaging was routinely obtained for all masses larger than 5 cm. High-risk radiographic features (intramuscular location, septations, nonfat nodules, heterogeneity, and ill-defined margins) and surgical pathology were evaluated to determine patients most likely to benefit from preoperative CNB.

RESULTS

Of 178 patients, 2 (1.1%) had malignant tumors on surgical pathology. All masses smaller than 5 cm were benign and, if imaging was obtained, had two or fewer high-risk radiographic features. Both of the patients with malignant tumors had masses larger than 5 cm, preoperative imaging that showed at least four high-risk radiographic features, and underwent CNB prior to excision.

CONCLUSIONS

The overall rate of malignancy is very low. The results of this study suggest that lipomatous masses smaller than 5 cm without concerning clinical characteristics do not require preoperative imaging or CNB. Conversely, lipomatous masses larger than 5 cm should undergo routine MRI with subsequent CNB if multiple high-risk radiographic features are present.

Risk Factors for Diagnostic Failure of Ultrasound-Guided Core Needle Biopsy of Soft-Tissue Tumors Based on World Health Organization Classification Category and Biologic Potential

OBJECTIVE. The purpose of this study is to evaluate the diagnostic outcome of ultrasound (US)-guided core needle biopsy (CNB) of soft-tissue tumors and to assess the factors associated with significant diagnostic failure. MATERIALS AND METHODS. We performed a retrospective analysis of biopsy specimens obtained from patients with soft-tissue tumors of the extremities and superficial trunk who underwent both US-guided CNB and surgical resection. In accordance with the World Health Organization classification, biopsy results and findings from final histologic analysis of the surgically resected specimen (hereafter known as final histologic findings) were categorized in terms of biologic potential as benign, intermediate (locally aggressive), intermediate (rarely metastasizing), or malignant. Biopsy results were considered to show a significant diagnostic failure if they resulted in incorrect classification of biologic potential compared with final histologic findings, if results were indeterminate, or if nondiagnostic specimens were obtained. World Health Organization classification categories and the biologic potential of the tumors according to final histologic findings were assessed to identify any relationship with diagnostic failure of CNB, as were other tumor- and patient-related factors. RESULTS. Significant diagnostic failure was seen for 40 of 303 biopsies (13.20%). Multivariate analysis showed a significant association between diagnostic failure and adipocytic tumors (odds ratio [OR], 9.686; p = 0.037) or vascular tumors (OR, 40.115; p = 0.005); intermediate (rarely metastasizing) biologic potential (OR, 12.279; p = 0.001), or malignant biologic potential (OR, 5.668; p < 0.001); and discordance between radiologic and final histologic findings or indeterminacy of biologic potential (OR, 2.500; p = 0.034). CONCLUSION. The World Health Organization classification categories (adipocytic or vascular), biologic potential (intermediate [rarely metastasizing] or malignant), and discordance between radiologic and final histologic findings or indeterminacy of biologic potential were found to be independent risk factors for significant diagnostic failure of CNB of soft-tissue tumors.

PET/CT-guided versus CT-guided percutaneous core biopsies in the diagnosis of bone tumors and tumor-like lesions: which is the better choice?

OBJECTIVE

The present study aimed to evaluate the diagnostic performance and safety of PET/CT-guided percutaneous core bone biopsy and to compare the PET/CT-guided method to conventional CT-guided percutaneous core biopsies to diagnose Chinese patients with bone tumors and tumor-like lesions.

METHODS

Data for 97 patients with bone tumors and tumor-like lesions diagnosed by percutaneous core bone biopsy from February 2013 to November 2018 were retrospectively analyzed. The study included 42 cases in the PET/CT group and 55 cases in the CT alone group. The diagnostic performance, cost and complications associated with the intervention were compared between the two groups. All patients were eventually confirmed to have bone tumors and tumor-like lesions according to surgical pathology findings.

RESULTS

There were no significant differences in patient characteristics (P > 0.05). For the patients in the PET/CT group, the overall diagnostic yield of the initial biopsies and the diagnostic accuracy derived from the surgically proven cases were both 97.62%, which was significantly higher than the values in the CT group during the same period (P < 0.05). No major biopsy-related complications (e.g., serious bleeding or tumor dissemination) occurred before, during, or after the intervention. Therefore, no significant difference was observed between the two groups with regard to the complication rate (P > 0.05).

CONCLUSION

Compared with CT-guided percutaneous bone biopsy, PET/CT-guided percutaneous bone biopsy is an effective and safe alternative with high diagnostic performance in the evaluation of hypermetabolic bone lesions to diagnose bone tumors and tumor-like lesions.

Radiomics and Machine Learning With Multiparametric Preoperative MRI May Accurately Predict the Histopathological Grades of Soft Tissue Sarcomas

BACKGROUND

Preoperative prediction of the grade of soft tissue sarcomas (STSs) is important because of its effect on treatment planning.

PURPOSE

To assess the value of radiomics features in distinguishing histological grades of STSs.

STUDY TYPE

Retrospective.

POPULATION

In all, 113 patients with pathology-confirmed low-grade (grade I), intermediate-grade (grade II), or high-grade (grade III) soft tissue sarcoma were collected.

FIELD STRENGTH/SEQUENCE

The 3.0T axial T₁ -weighted imaging (T₁ WI) with 550 msec repetition time (TR); 18 msec echo time (TE), 312 × 312 matrix, fat-suppressed fast spin-echo T₂ WI with 4291 msec TR, 85 msec TE, 312 × 312 matrix.

ASSESSMENT

Multiple machine-learning methods were trained to establish classification models for predicting STS grades. Eighty STS patients (18 low-grade [grade I]; 62 high-grade [grades II-III]) were enrolled in the primary set and we tested the model with a validation set with 33 patients (7 low-grade, 26 high-grade).

STATISTICAL TESTS

1) Student's t-tests were applied for continuous variables and the χ² test were applied for categorical variables between low-grade STS and high-grade STS groups. 2) For feature subset selection, either no subset selection or recursive feature elimination was performed. This technology was combined with random forest and support vector machine-learning methods. Finally, to overcome the disparity in the frequencies of the STS grades, each machine-learning model was trained i) without subsampling, ii) with the synthetic minority oversampling technique, and iii) with random oversampling examples, for a total of 12 combinations of machine-learning algorithms that were assessed, trained, and tested in the validation cohort.

RESULTS

The best classification model for the prediction of STS grade was a combination of features selected by recursive feature elimination and random forest classification algorithms with a synthetic minority oversampling technique, which had an area under the curve of 0.9615 (95% confidence interval 0.8944-1.0) in the validation set.

DATA CONCLUSION

Radiomics feature-based machine-learning methods are useful for distinguishing STS grades.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:791-797.

Soft Tissue Sarcomas: Preoperative Predictive Histopathological Grading Based on Radiomics of MRI

RATIONALE AND OBJECTIVES

The purpose of this study is to develop a radiomics model for predicting the histopathological grades of soft tissue sarcomas preoperatively through magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Thirty-five patients who were pathologically diagnosed with soft tissue sarcomas and their histological grades were recruited. All patients had undergone MRI before surgery on a 3.0T MRI scanner. Radiomics features were extracted from fat-suppressed T2-weighted imaging. We used the least absolute shrinkage and selection operator (LASSO) regression method to select features. Then three machine learning classification methods, including random forests, k-nearest neighbor, and support vector machine algorithm were trained using the 5-fold cross validation strategy to separate the soft tissue sarcomas with low- and high-histopathological grades.

RESULTS

The radiomics features were significantly associated with the histopathological grades. Quantitative imaging features (n = 1049) were extracted from fat-suppressed T2-weighted imaging, and five features were selected to construct the radiomics model. The model that used support vector machine classification method achieved the best performance among the three methods, with areas under the receiver operating characteristic curves Area Under Curve (AUC) values of 0.92 ± 0.07, accuracy of 0.88.

CONCLUSION

Good accuracy and AUC could be obtained using only five radiomic features. Therefore, we proposed that three-dimensional imaging features from fat-suppressed T2-weighted imaging could be used as candidate biomarkers for preoperative prediction of histopathological grades of soft tissue sarcomas noninvasively.

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.

Value of CT-guided percutaneous needle biopsy of bone in the diagnosis of lymphomas based on PET/CT results

Background

To evaluate the value of CT-guided percutaneous needle biopsy of bone in the diagnosis of lymphomas based on PET/CT results.

Methods

A retrospective analysis of the records of all patients with percutaneous bone biopsies based on PET/CT results and a final diagnosis of lymphoma between January 2012 and August 2017 was performed. Thirty-one patients were included in this study. The success and complication rates were assessed.

Results

The mean age of the 31 patients was 46.6 ± 21.2 years, and there were 16 men and 15 women. A definite diagnosis and accurate histological subtype were obtained in 26 patients, for a success rate of 84%. The most common subtype was diffuse large B cell lymphoma (n = 18). The remaining subtypes included three cases of marginal-zone lymphoma, two cases of follicular lymphoma, one case of Hodgkin’s lymphoma, one case of peripheral T cell lymphoma, and one case of B cell lymphoblastic lymphoma. No serious complications occurred in any of the patients.

Conclusions

CT-guided needle biopsy based on PET/CT results is a reliable means of diagnosing and classifying lymphomas.

The diagnostic significance of repeat ultrasound-guided biopsy of musculoskeletal soft-tissue lesions with initially inconclusive biopsy results

INTRODUCTION

To determine the diagnostic yield of repeat ultrasound (US)-guided biopsy of musculoskeletal soft-tissue lesions with initially inconclusive biopsy results, and to explore predictive factors for success of repeat biopsy.

MATERIALS AND METHODS

This retrospective study included 42 patients who underwent a repeat (second) US-guided biopsy session to target a musculoskeletal soft-tissue lesion because an initial US-guided biopsy session provided inconclusive results. Both biopsy sessions were performed in a tertiary referral center for soft-tissue sarcomas.

RESULTS

The diagnostic yield of repeat US-guided biopsy was 47.6%. Malignant nature of the lesion (P = 0.031), sharp lesion borders on US (P = 0.011), and good to very good lesion visibility on US (P = 0.017) were significantly associated with a diagnostic repeat US-guided biopsy. There was also a trend towards significance (P = 0.073) for a higher number of biopsy passes through the lesion. Other patient characteristics (age and gender), magnetic resonance imaging features (lesion homogeneity on T1-weighted, T2-weighted, and gadolinium chelate enhanced sequences, borders, enhancement pattern, depth and size), US features (lesion appearance, vascular flow, and depth), biopsy-related factors (days between initial and repeat US-guided biopsy, needle diameter, maximum length of acquired samples), and operator-related factors (same or different radiologists/pathologists for initial and repeat biopsies), were not associated with the diagnostic success of the repeat US-guided biopsy.

CONCLUSIONS

Repeat US-guided biopsy of a musculoskeletal soft-tissue lesion with initially inconclusive biopsy results can be useful to establish a final diagnosis. Lesion features on US (borders and visibility) may be used to prospectively determine the utility of a repeat US-guided biopsy.

Bone and Soft-Tissue Biopsies: What You Need to Know

Percutaneous, image-guided musculoskeletal biopsy, due to its minimal invasive nature, when compared with open surgical biopsy, is a safe and effective technique which is widely used in many institutions as the primary method to acquire tissue and bone samples. Indications include histopathologic and molecular assessment of a musculoskeletal lesion, exclusion of malignancy in a bone/vertebral fracture, examination of bone marrow, and infection investigation. Preprocedural workup should include both imaging (for lesion assessment and staging) and laboratory (including coagulation tests and platelet count) studies. In selected cases, antibiotic prophylaxis should be administered before the biopsy. Core needle biopsy of musculoskeletal lesions has a diagnostic accuracy that ranges from 66 to 98% with higher diagnostic yield for lytic, large-size, malignant lesions and when multiple and long specimens are obtained. Reported complication rates range between 0 and 10% and usually do not exceed 5%, with a suggested threshold of 2%. The purpose of this review article is to illustrate the technical aspects, the indications, and the methodology of percutaneous image-guided bone biopsy that will assist the interventional radiologist to perform these minimal invasive techniques.

Percutaneous CT-guided sternal biopsy: factors affecting the diagnostic yield

Background Sternal lesions are occasionally seen in clinical practice and their diagnosis can be important, especially for oncologic patients. However, percutaneous computed tomography (CT)-guided biopsy of sternal lesions is rarely performed. Purpose To assess the diagnostic yield of percutaneous CT-guided sternal biopsies and to analyze the factors that affect diagnostic yield. Material and Methods A retrospective review of 34 patients who underwent CT-guided sternal biopsy was carried out at a single institution. Pre-biopsy CT density, location, penetration length of biopsy needle, number of biopsy attempts, angle of needle approach, final diagnosis, and operator experience level were recorded. A biopsy was considered as diagnostic if it provided a confident pathologic result. All variables were compared using Chi-square tests. Results Twenty-two of the 34 (64.7%) biopsy procedures yielded a diagnostic sample and 12 (35.3%) were non-diagnostic. Eight participants in the non-diagnostic group were clinically diagnosed with inflammatory arthritis of the manubriosternal or costosternal joints. Longer penetration distance of the tumor by the biopsy needle showed higher diagnostic yield ( P = 0.031). Osteoblastic lesions ( P < 0.001), lesions in the manubriosternal joint ( P = 0.018) and approaches using more obtuse angles ( P = 0.009) were associated with significantly lower diagnostic yields. Malignancy in the final diagnosis led to a higher diagnostic yield than benign lesions ( P < 0.001). Conclusion CT-guided percutaneous sternal biopsy has a relatively lower diagnostic yield. However, acute angle of needle approach may help increase biopsy success rate. Osteoblastic lesions and lesions in the manubriosternal joint tend to have lower diagnostic yield.