Benign Bone Conditions That May Be FDG-avid and Mimic Malignancy

Enchondroma on Bone Scan and PSMA PET/CT in a Patient With Prostate cancer

ABSTRACT

A 54-year-old man with Gleason 9 prostate cancer with reported nodal and skeletal metastases was referred to us. Outside hospital reports described abnormal left proximal humerus activity on bone scan concerning for metastasis; however, concurrent PSMA PET/CT did not show activity in this lesion. Further review of the PET/CT images revealed characteristic features of enchondroma in the left humeral lesion.

Disseminated Mycobacterium kansasii infection due to surgical site infection following allogeneic hematopoietic stem cell transplantation: A case report and literature review

This report details a rare case of surgical site infection (SSI) caused by Mycobacterium kansasii following allogeneic hematopoietic stem cell transplantation (allo-HSCT) in a 53-year-old patient with IgA-κ type multiple myeloma. After undergoing multiple chemotherapy regimens and two stem cell transplants, the patient developed an SSI 31 months post-transplantation, manifesting as an intracranial abscess at the site of a previous craniotomy. M. kansasii was isolated from the drainage fluid, marking this instance as a unique case in the literature of NTM infection post-allo-HSCT with such a delayed onset. The patient's treatment included targeted antimicrobial therapy based on susceptibility testing, resulting in eventual resolution of the infection, although the patient later succumbed to multiple myeloma relapse. This case underscores the critical need to consider NTM infections in the differential diagnosis of persistent fevers and SSIs in immunocompromised patients, particularly those with chronic graft-versus-host disease. It highlights the importance of early diagnostic and therapeutic interventions to manage these infections effectively. This report contributes to the limited but growing body of literature on NTM infections post-allo-HSCT and emphasizes the need for vigilance in monitoring postoperative patients, especially those with prolonged immunosuppression.

FDG-Avid Periprosthetic Particle Disease Mimicking Osteosarcoma Recurrence

ABSTRACT

A 24-year-old man with a history of osteosarcoma presented with swelling in his right thigh for more than 1 year. 18 F-FDG PET/CT demonstrated increased FDG uptake in multiple juxtacortical masses around the prosthesis, which highly suggested the possibility of osteosarcoma recurrence. A biopsy was performed, and the pathology confirmed the diagnosis of particle disease. The current case indicates that particle disease should be considered when interpreting the PET/CT images with high FDG uptake around the prosthesis.

Value of subspecialist second opinion reads of 18 F-FDG PET-CT examinations for patients with breast cancer

OBJECTIVES

Determine if subspecialist second opinion review alters reporting of malignancy on 18 F-FDG PET/CT for patients with breast cancer.

METHODS

This IRB-approved retrospective study compared 248 s opinion reads of 18 F-FDG PET/CT exams performed for patients with breast cancer against the original outside institution reports. Subspecialist reviews documented if malignant findings on the outside report were believed to be malignant and noted additional malignant findings not described on the outside report. Reference standard for malignancy or benignity was determined by pathology or follow-up imaging.

RESULTS

Of 248 cases, 27 (11%) had discrepancies in the presence or absence of extra-axillary nodal or distant metastases. Of these 27, 14 (52%) had biopsy or imaging follow-up as a reference standard for malignancy/benignity. In cases with reference standard proof, the subspecialist second opinion review was correct in 13/14 (93%) of cases. This included eleven cases that the original report called malignant, but the subspecialist review called benign and subsequently proven to be benign; as well as two metastases called on subspecialist review, but not on the original report, and subsequently biopsy proven to be metastases. In one case, the second opinion read called a suspicious lesion that was biopsy proven to be benign.

CONCLUSION

Subspecialist review improves the accuracy of diagnosis for the presence or absence of malignancy on FDG PET/CT examinations in patients with breast cancer. This demonstrates the value of performing second opinion reads of 18 F-FDG PET/CT studies in patients with breast cancer, particularly by subspecialist second opinion review reducing false positive reads.

Brown tumors in nuclear medicine: a systematic review

Brown tumors (BT) are abnormal bone-repair processes and a consequence of hyperparathyroidism. The diagnosis of these lytic lesions in nuclear medicine, while a challenge, is not so rare, because functional imaging is used both in the management of cancer and hyperparathyroidism. The main objective of this review is to summarize the knowledge and the evidence concerning BT and the different imaging modalities in nuclear medicine. A systematic review was performed in Embase, PubMed and Google Scholar from 2005 to 2022. We included articles describing BT in the following imaging modalities: [¹⁸F]-fluorodeoxyglucose PET/CT, [¹⁸F]-fluorocholine or [¹¹C]-fluorocholine PET/CT, [^99mTc]-Sestamibi scintigraphy, bone scan, [¹⁸F]-sodium fluoride PET/CT, [⁶⁸Ga]-FAPI PET/CT; [⁶⁸Ga]-DOTATATE PET/CT; [¹¹C]-methionine PET/CT. For each modality, appearance, avidity for radiotracer, available quantitative parameters and imaging evolution after parathyroidectomy were collected and analyzed. Fifty-two articles were included for a total of 392 BT lesions. If the diagnosis of BT is evoked on a known lesion, performing a [¹⁸F]-fluorocholine PET/CT imaging seems the most appropriate. In [¹⁸F]-fluorodeoxyglucose, [¹⁸F]-fluorocholine, [¹⁸F]-sodium fluoride PET/CT and bone scan, BT can mimic metastatic disease. BT uptakes appear reversible after parathyroidectomy, with a more or less rapid decrease depending on the imaging modality used.

Detection of Bone Metastases by 68Ga-DOTA-SSAs and 18F-FDG PET/CT: A Two-Center Head-to-Head Study of Gastroenteropancreatic Neuroendocrine Neoplasms

Purpose

This study aimed to assess the efficacy of dual-tracer [⁶⁸Ga-DOTA-somatostatin receptor analogs (SSAs) and ¹⁸F-fluorodeoxyglucose (FDG)] positron emission tomography/computed tomography (PET/CT) imaging for detecting bone metastases (BMs) in patients with gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs).

Methods

We retrospectively enrolled 74 GEP-NEN patients with BMs from two centers, who underwent dual-tracer PET/CT from January 2014 to March 2021. We compared and analyzed effectiveness of the dual PET/CT imaging techniques on the BMs, based on ¹⁸F-FDG and ⁶⁸Ga-DOTA-SSAs. Specifically, we analyzed the imaging results using χ ² tests for classification variables, paired-sample tests for number of BMs, Wilcoxon's signed rank test for number of lesions, and the Kruskal-Wallis test for standard uptake value (SUV) ratio comparison. The correlation of dual-tracer SUVmax with Ki-67 index was analyzed by Spearman's correlation coefficient.

Results

The detection efficiencies of dual-tracer PET/CT imaging in patients with different pathologies showed discordant for detecting liver metastases and BMs in group neuroendocrine tumor (NET) G3, ⁶⁸Ga-DOTA-SSAs was better at detecting BMs for NET G3 (P=0.049 for SUV_T/B and P=0.026 for the number of metastatic lesions). In addition, statistical significance was found among osteogenesis group, osteolysis group, and the no-change group (for bone SUV_T/B value detected by ¹⁸F-FDG and Ki-67 index, osteogenesis group < osteolysis group; for bone SUV_T/B detected by ⁶⁸Ga-DOTA-SSAs, osteogenesis group > the no-change group). What is more, liver and bone SUVmax and Ki-67 index were positively correlated in ¹⁸F-FDG imaging (P < 0.001 for liver; P=0.002 for bone), and negatively correlated in ⁶⁸Ga-DOTA-SSAs imaging (P < 0.001 for liver; P=0.039 for bone).

Conclusions

⁶⁸Ga-DOTA-SSAs was superior to ¹⁸F-FDG for detecting BMs in NET G1/G2 (well and moderately differentiated NETs), as well as in NET G3 (poorly differentiated NETs). Relatively good differentiation was observed in the osteogenesis group. In addition, dual-tracer PET/CT imaging results were observably correlated with tumor differentiation.

FDG PET/CT and Bone Scintigraphy in Desmoplastic Fibroma of the Bone

ABSTRACT

Desmoplastic fibroma is a very rare benign bone tumor with local aggressiveness. We describe imaging findings in 2 cases with desmoplastic fibroma of the bone. One case had a desmoplastic fibroma in the right distal femur, showing bone destruction with sclerotic margins and inhomogeneous FDG uptake. The other case had a desmoplastic fibroma in the left ninth rib, showing progressive peripheral enhancement and increased 99m Tc-MDP uptake.

Common Skeletal Neoplasms and Nonneoplastic Lesions at 18F-FDG PET/CT

Numerous primary and metastatic osseous lesions and incidental osseous findings are encountered at fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) PET/CT. These lesions show varying degrees of FDG uptake. Malignancies are generally more FDG avid than are benign lesions, but many exceptions exist. Although aggressive lesions tend to be more FDG avid than nonaggressive lesions, this concept holds true particularly for lesions of the same histologic subtype. In addition, some benign osseous processes such as Paget disease have variable degrees of FDG avidity on the basis of disease metabolic activity. This creates a diagnostic dilemma for radiologists and clinicians, especially in patients with known malignancies, and can result in unnecessary diagnostic imaging or interventions for incidental osseous lesions. Evaluation of morphologic CT characteristics of osseous lesions at FDG PET/CT can be a valuable adjunct to metabolic analysis to further characterize lesions, enhance diagnostic and staging accuracy, and avoid unnecessary invasive biopsy procedures. The authors review the common primary and metastatic bone lesions at FDG PET/CT, with an emphasis on morphologic CT assessment of lesions to help narrow the differential diagnosis. Imaging manifestations of common incidental nonneoplastic bone lesions at FDG PET/CT are discussed to provide information on differentiation of these lesions from osseous neoplasms. The guidelines of the National Comprehensive Cancer Network (NCCN) for common primary osseous malignancies are also summarized. Online supplemental material is available for this article. ^©RSNA, 2021.

Measuring Heterogeneity in 18F-Fluorodeoxyglucose Positron Emission Tomography Images for Classifying Metastatic and Benign Bone Lesions in Patients with Cervical Cancer

Purpose

Heterogeneity assessment can be applied for medical imaging analysis. Here, we evaluated first-order and texture analysis (TA) metrics in 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) imaging for classification of metastatic and benign bone lesions in patients with cervical cancer.

Methods

The data of 18F-FDG PET studies performed on a specific PET/CT system from 2016 to 2018 in patients with cervical cancer were retrieved. The data of bone lesions extracted from studies over 2016–2017 and 2018 were used as training and validation datasets, respectively. Metastatic bone lesions were identified in each dataset, with an equal number of benign bone lesions selected. Cuboid volume of interest (VOI) consisting of 3 × 3 × 5 reconstructed voxels was applied for first-order metrics, and cubic VOI consisting of smaller voxels with trilinear interpolation of standardized uptake value (SUV) was adopted for TA metrics. First-order metrics included the maximum SUV (SUVmax) of lesions and the mean voxel SUV and its standard deviation (SUVsd), skewness, and kurtosis in VOI. In total, 4464 TA metrics based on 62 texture features were evaluated. Logistic regression was used for classification with area under the receiver operating characteristic curve (AUC) as the performance measure.

Results

From the training and validation datasets, 98 and 42 metastatic bone lesions were identified, respectively. SUVsd demonstrated higher performance than did SUVmax in both the training (AUC .798 vs .732, P = .001) and validation (AUC .786 vs .684, P < .001) datasets. Top-performing TA metrics demonstrated significantly higher performance in the training dataset, but not in the validation dataset.

Conclusion

A simple first-order measure of heterogeneity, SUVsd, was found to be superior to SUVmax for the classification of metastatic and benign bone lesions. Multiple hypothesis testing can result in false-positive findings in TA with multiple features and parameters; careful validation is required.

Bone Marrow Activation After Chemotherapy Presenting as Diffuse Skeletal Uptake on 18F-Fluorocholine PET/CT

ABSTRACT

Diffuse 18F-FDG skeletal uptake due to chemotherapy-induced bone marrow activation is well documented, whereas it has never been reported with 18F-fluorocholine. We described a patient with pelvic recurrence of prostate cancer at 18F-fluorocholine PET/CT. A second PET/CT after docetaxel showed minimal residual activity in pelvis, but it revealed diffuse, intense 18F-fluorocholine skeletal uptake. Considering biochemical and metabolic response and absence of morphologically suspected bone lesions, skeletal hyperactivity was interpreted as chemotherapy-related bone marrow rebound rather than diffuse metastatic involvement, as confirmed by its resolution after treatment ended. The occurrence of such 18F-fluorocholine pattern should be considered to avoid imaging misinterpretation.

Significant Improvement After Surgery for a Symptomatic Osteoblastoma in a Patient with Camurati-Engelmann Disease: Case Report and Literature Review

Camurati-Engelmann disease (CED) is a rare, progressive diaphyseal dysplasia characterized as diaphyseal hyperostosis and sclerosis of the long bones. Corticosteroids, bisphosphonates, and losartan have been reported to be effective systemic medications used to reduce CED symptoms. There are no reports of osteoblastoma in patients with CED, and osteoblastoma in the distal radius is rare. We present a patient diagnosed with CED, based on radiological and histological examinations, at 11 years old. At 22 years old, she experienced severe pain in her right forearm and was treated with bisphosphonate, losartan, and prednisolone; however, the pain continued. An expansive and sclerotic lesion at the distal radius was observed on radiography. A follow-up plain radiograph indicated that the lesion was growing. Fluorodeoxyglucose positron emission tomography revealed solitary, intense radiotracer uptake, and a biopsy and surgical resection were performed due to suspected malignancy. Pathologic analysis showed anastomosing bony trabeculae rimmed by osteoblasts observed in a loose fibrovascular stroma. The lesion was diagnosed as an osteoblastoma. Following bone excision and artificial bone grafting, the patient's severe pain almost completely disappeared. At final follow-up, no evidence of osteoblastoma recurrence was noted. To our knowledge, this is the first case report of osteoblastoma arising in a patient with CED. Bone excision and artificial bone grafting may be a treatment option for local symptomatic osteoblastoma in patients with CED.

An international expert opinion statement on the utility of PET/MR for imaging of skeletal metastases

BACKGROUND

MR is an important imaging modality for evaluating musculoskeletal malignancies owing to its high soft tissue contrast and its ability to acquire multiparametric information. PET provides quantitative molecular and physiologic information and is a critical tool in the diagnosis and staging of several malignancies. PET/MR, which can take advantage of its constituent modalities, is uniquely suited for evaluating skeletal metastases. We reviewed the current evidence of PET/MR in assessing for skeletal metastases and provided recommendations for its use.

METHODS

We searched for the peer reviewed literature related to the usage of PET/MR in the settings of osseous metastases. In addition, expert opinions, practices, and protocols of major research institutions performing research on PET/MR of skeletal metastases were considered.

RESULTS

Peer-reviewed published literature was included. Nuclear medicine and radiology experts, including those from 13 major PET/MR centers, shared the gained expertise on PET/MR use for evaluating skeletal metastases and contributed to a consensus expert opinion statement. [18F]-FDG and non [18F]-FDG PET/MR may provide key advantages over PET/CT in the evaluation for osseous metastases in several primary malignancies.

CONCLUSION

PET/MR should be considered for staging of malignancies where there is a high likelihood of osseous metastatic disease based on the characteristics of the primary malignancy, hight clinical suspicious and in case, where the presence of osseous metastases will have an impact on patient management. Appropriate choice of tumor-specific radiopharmaceuticals, as well as stringent adherence to PET and MR protocols, should be employed.

Team Approach: Evaluation and Management of Low-Grade Cartilaginous Lesions

» Assessment of chondral lesions begins with a clinical evaluation and radiographs. » Longitudinal follow-up with serial radiographs is appropriate in cases without evidence of aggressive radiographic features. » Concerning radiographic features include periosteal reaction, soft-tissue extension, cortical destruction, endosteal scalloping of greater than two-thirds of the native cortex, larger lesion size (≥5 cm), and location in the axial skeleton. » Biomarkers such as IMP3, SOX4, microRNA, and periostin may be used as an adjunct in histologic assessment to help differentiate benign enchondroma from a low-grade chondrosarcoma. » Advanced-imaging studies, such as computed tomography (CT), bone scans, magnetic resonance imaging (MRI), dynamic contrast-enhanced MRI, and fluorodeoxyglucose positron emission tomography (FDG-PET), may be considered for borderline cases. » Aggressive or concerning radiographic features should prompt evaluation with advanced imaging or referral to an orthopaedic oncologist.

18F-fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of spinal giant cell tumors

OBJECTIVE

To investigate the value of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in the evaluation of spinal giant cell tumors (GCTs).

MATERIALS AND METHODS

The PET/CT and clinical data of 16 patients with spinal GCTs were reviewed. The maximal standardized uptake value (SUVmax), longest diameter, and CT features of spinal GCTs were analyzed. The value of PET/CT and MRI in displaying the recurrent lesions was compared. PET Response Criteria in Solid Tumors were adopted to evaluate the response to radiotherapy.

RESULTS

Data from 7 males and 9 females (median age 32.5 years) were analyzed. Eight patients had primary GCTs with a median SUVmax of 11.91 and a median length of 4.42 cm. Eight patients had relapsed GCTs with a median SUVmax of 10.34 and a median length of 6.23 cm. There was no statistical difference between the SUVmax of primary and relapsed GCTs. The SUVmax did not correlate with length. In 8 relapsed patients, 4 lesions invaded the vertebral canal, but 2 of which were not displayed on MRI. Metal prostheses showed extremely low signal intensity on MRI, even in the 3 cases with increased intra-prosthetic ¹⁸F-FDG concentration. Five relapsed patients with subsequent radiotherapy had a repeat PET/CT. A complete, partial, and stable metabolic response was observed in 1, 3, and 1 patient, respectively.

CONCLUSIONS

Both the primary and recurrent spinal GCTs avidly accumulate ¹⁸F-FDG. For recurrent GCTs, PET/CT may provide incremental value in the assessment of the vertebral canal and intra-prosthetic involvement and the response to radiotherapy.

Elevated 68Ga-DOTATATE Activity in Fibrous Cortical Defect

FDG PET/CT was performed for staging in a 15-year-old adolescent girl with cholangiocarcinoma, which showed only mild activity in the tumor but more impressive FDG activity in right femoral fibrous cortical defect without any other hypermetabolic lesions elsewhere. Pathological examination of the resected cholangiocarcinoma revealed significant neuroendocrine differentiation, which lead to subsequent Ga-DOTATATE PET/CT study. Unexpectedly, the same femoral fibrous cortical defect also had increased Ga-DOTATATE activity.

The minimally invasive endoscopic technique for the treatment of symptomatic benign bone lesions: Preliminary results from a retrospective study

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Symptomatic benign bone lesions may cause pain and refractory limp. Conventional open surgery usually involves high risks of complications, which may greatly compromise the overall efficacy of surgery in the long term.

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This single-institution retrospective study of 34 patients with symptomatic benign bone lesions. All surgical procedures were performed under endoscopic guidance for direct visualization followed by complete curettage of tumor tissue.

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Patients reported significant improvements in pain, quality of life and functional recovery without complications or need for secondary interventions.

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Study limitations included a relatively small population of Chinese patients and the lack of a comparative surgical or other minimally invasive techniques.

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The procedure described may be a valuable alternative to open surgery for symptomatic benign bone lesions.

Objective

The present study aimed to evaluate the short-term clinical feasibility and efficacy of the minimally invasive endoscopic technique (MIET) for the treatment of symptomatic benign bone lesions.

Materials and methods

This single-institution retrospective study investigated 34 patients with symptomatic benign bone lesions from December 2015 to June 2017. Patients involved in this study presented with definite indications for surgical intervention. All procedures were performed under endoscopic guidance for direct visualization followed by complete curettage of tumor tissue. There were 19 males and 15 females, with a mean age of 33.3 ± 12.7 years (range, 17–68 years). The lesions were located in the upper extremities (20, 58.8%), lower extremities (9, 26.5%) and pelvis (5, 14.7%). Primary outcomes were measured before and after intervention using the visual analog scale (VAS), the Musculoskeletal Tumor Society (MSTS) stage and the 36-item Short-Form Health Survey (SF-36) scoring system.

Results

Of the 34 patients included in this study, all completed follow-up examinations, with a mean follow-up duration of 22.4 ± 7.6 months (range, 13–35 months). Significantly improved VAS, MSTS and SF-36 scores were observed at 3 months after the initial treatment (P < 0.001), suggesting enhanced pain relief and improved functional recovery and quality of life following surgery. All procedures were technically successful, with the exception of 3 cases (8.8%) manifesting access site numbness; these patients recovered within the follow-up period through symptomatic treatment alone. Only 2 patients (5.9%; one osteoblastoma and one enchondroma) experienced local recurrence and underwent standard open curettage within the follow-up period. All patients showed functional stability without any major complications.

Conclusion

The MIET is an effective and safe alternative treatment for symptomatic benign bone lesions. The short-term efficacy of MIET was favorable and associated with improved pain palliation, quality of life and functional recovery.

The Spectrum of Rib Neoplasms in Adults: A Practical Approach and Multimodal Imaging Review

OBJECTIVE. Adult neoplasms of the ribs are a heterogeneous group consisting of both benign and aggressive entities. Rib neoplasms have a variety of overlapping imaging features, with much of the imaging data disjointed across the musculoskeletal, thoracic, and oncologic imaging literature. Arrival at accurate diagnosis can therefore be quite challenging. This article consolidates this information and introduces the reader to an algorithmic approach to rib lesion evaluation based on imaging. CONCLUSION. Rib neoplasms are a diverse group of benign and malignant entities, which often makes determining an accurate diagnosis challenging. Evaluation requires a multipronged approach that incorporates radiographic imaging features, nonradiographic imaging findings, lesion location, and clinical data.

The value of prebiopsy FDG-PET/CT in discriminating malignant from benign vertebral bone lesions in a predominantly oncologic population

PURPOSE

To determine the value of prebiopsy ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET)/computed tomography (CT) in discriminating malignant from benign vertebral bone lesions.

MATERIALS AND METHODS

This retrospective study included 53 patients with 55 vertebral bone lesions that underwent FDG-PET/CT before CT-guided biopsy. Pathologic examination of the biopsy sample and a minimum follow-up of 1 year were used as reference standard.

RESULTS

Sensitivity, specificity, positive predictive value, and negative predictive value of visual FDG-PET analysis (with lesion FDG uptake higher than liver FDG uptake as threshold for malignancy) in discriminating malignant from benign vertebral bone lesions were 91.3% (42/46), 22.2% (2/9), 85.7% (42/49), and 33.3% (2/6), respectively. The semiquantitative FDG-PET metrics SUV_max and SUV_peak achieved areas under the receiver operating characteristics curve of 0.630 and 0.671, respectively. Malignant lesions demonstrated bone lysis more frequently than benign lesions (60.9% (28/46) vs. 22.2% (2/9)), and this difference was nearly significant (P = 0.064). All other clinical and conventional imaging characteristics (including patient age, gender, previous diagnosis of malignancy, bone pain, weight loss, any CT abnormality, sclerosis, cortical destruction, bone marrow replacement, associated extraosseous soft tissue mass, and accompanying vertebral height loss, multiple bone lesions on FDG-PET/CT, and suspicious extraosseous lesions on FDG-PET/CT) were not significantly different (P = 0.143 to 1.000).

CONCLUSION

FDG-PET/CT may steer the diagnosis (particularly thanks to a relatively high PPV and value of semiquantitative measurements), but cannot always classify vertebral bone lesions as malignant or benign with sufficient certainty. In these cases, biopsy and/or follow-up remain necessary to establish a final diagnosis.

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.