[18F]Fluoride Positron-Emission Tomography (PET) and [18F]FDG PET for Assessment of Osteomyelitis of the Jaw in Comparison to Computed Tomography (CT) and Magnetic Resonance Imaging (MRI): A Prospective PET/CT and PET/MRI Pilot Study

The usefulness of different imaging modalities in mandibular osteonecrosis and osteomyelitis diagnosis

To examine the CT-imaging features of subjects with bacterial osteomyelitis (OM), osteoradionecrosis (ORN), and medication-related osteonecrosis of the jaw (MRONJ) with histopathological confirmation, and to examine the diagnostic efficacy of panoramic radiography and MRI in detecting these disease features. 150 cases with preoperative CT data were selected: 61 bacterial OM, 19 ORN, and 70 MRONJ. 143 cases underwent panoramic X-ray examination, and 47 underwent MRI. The assessment criteria for imaging findings included: (1) bone resorption, (2) osteosclerosis, (3) clarity of the mandibular canal, (4) periosteal reactions, (5) cortical bone perforation, (6) sequestrum, and (7) pathological fractures. CT was considered the gold standard for assessing these features. Compared with CT, all panoramic radiographs were detectable for diagnostic features of the disease. Bone resorption was detected in 123 cases (sensitivity 91.1%), and osteosclerosis was detected in 131 cases (sensitivity 98.5%). With panoramic radiography, most changes to clarity of the mandibular canal and pathological fractures were detected (sensitivities of 87.8% and 68.8%, respectively). However, the sensitivities for detection of periosteal reactions, cortical bone perforation and sequestration were low (19.6%, 17.8% and 19.4%, respectively). Sensitivity of MRI for detecting periosteal reactions, cortical bone perforation, sequestration, and pathological fractures (27.3%, 73.5%, 35.7%, and 60.0%, respectively) was equivalent or superior to panoramic imaging. MR-specific characteristics of bone marrow edema were depicted on almost all examinations. Panoramic radiography may be adequate for identifying bone resorption and osteosclerosis. However, MRI provides more value than panoramic radiography in detecting periosteal reactions, cortical bone perforation, sequestration, and bone marrow edema.

Positron Emission Tomography-Magnetic Resonance Imaging, a New Hybrid Imaging Modality for Dentomaxillofacial Malignancies-A Systematic Review

Background/Objectives: Emerging hybrid imaging modalities, like Positron Emission Tomography/Computed Tomography (PET/CT) and Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI), are useful for assessing head and neck cancer (HNC) and its prognosis during follow-up. PET/MRI systems enable simultaneous PET and MRI scans within a single session. These combined PET/MRI scanners merge MRI's better soft tissue contrast and the molecular metabolic information offered by PET. Aim: To review scientific articles on the use of hybrid PET/MRI techniques in diagnosing dentomaxillofacial malignancies. Method: The available literature on the use of PET/MRI for the diagnosis of dentomaxillofacial malignancies in four online databases (Scopus, PubMed, Web of Science, and the Cochrane Library) was searched. Eligible for this review were original full-text articles on PET/MRI imaging, published between January 2010 and November 2024, based on experimental or clinical research involving humans. Results: Out of the 783 articles retrieved, only twelve articles were included in this systematic review. Nearly half of the articles (5 out of 12) concluded that PET/MRI is superior to PET, MRI, and PET/CT imaging in relation to defining malignancies' size. Six articles found no statistically significant results and the diagnostic accuracy presented was similar in PET/MRI versus MRI and PET/CT images. Regarding the overall risk of bias, most articles had a moderate risk. Conclusions: The use of PET/MRI in HNC cases provides a more accurate diagnosis regarding dimensions of the tumor and thus a more accurate surgical approach if needed. Further prospective studies on a larger cohort of patients are required to obtain more accurate results on the application of hybrid PET/MRI.

Validation of quantitative [18F]NaF PET uptake parameters in bone diseases: a systematic review

PURPOSE

[18F]NaF PET has become an increasingly important tool in clinical practice toward understanding and evaluating diseases and conditions in which bone metabolism is disrupted. Full kinetic analysis using nonlinear regression (NLR) with a two-tissue compartment model to determine the net rate of influx (Ki) of [18F]NaF is considered the gold standard for quantification of [18F]NaF uptake. However, dynamic scanning often is impractical in a clinical setting, leading to the development of simplified semi-quantitative parameters. This systematic review investigated which uptake parameters have been used to evaluate bone disorders and how they have been validated to measure disease activity.

METHODS

A literature search (in PubMed, Embase.com, and Clarivate Analytics/Web of Science Core Collection) was performed up to 28th November 2023, in collaboration with an information specialist. Each database was searched for relevant literature regarding the use of [18F]NAF PET/CT to measure disease activity in bone-related disorders. The main aim was to explore whether the reported semi-quantitative uptake values were validated against full kinetic analysis. A second aim was to investigate whether the chosen uptake parameter correlated with a disease-specific outcome or marker, validating its use as a clinical outcome or disease marker.

RESULTS

The initial search included 1636 articles leading to 92 studies spanning 29 different bone-related conditions in which [18F]NaF PET was used to quantify [18F]NaF uptake. In 12 bone-related disorders, kinetic analysis was performed and compared with simplified uptake parameters. SUVmean (standardized uptake value) and SUVmax were used most frequently, though normalization of these values varied greatly between studies. In some disorders, various studies were performed evaluating [18F]NaF uptake as a marker of bone metabolism, but unfortunately, not all studies used this same approach, making it difficult to compare results between those studies.

CONCLUSION

When using [18F]NaF PET to evaluate disease activity or treatment response in various bone-related disorders, it is essential to detail scanning protocols and analytical procedures. The most accurate outcome parameter can only be obtained through kinetic analysis and is better suited for research. Simplified uptake parameters are better suited for routine clinical practice and repeated measurements.

Bone Tumors of the Jaw - the "Blind Spot" for Radiologists Experienced with Tumors? - Part II

Primary bone tumours of the jaw are rare tumoral entities and do substantially differ from other bone tumours of the human body with respect of their frequently encountered unusual radiological appearances. The reason for that may be confined to the co-existence of two closely neighbored but different anatomical structures (i.e., tooth-forming apparatus and jaw bones with adjacent gingiva) and some tumour pathologies which are nearly excusively encountered in the jaw bones only (e.g., ameloblastoma, ossifying fibroma, ghost cell carcinoma).This paper would like to highlight some basic principles of the diagnostic approach and possibilities of radiological differentiation of such tumour-suspicious changes within the gnathic system are elucidated and discussed.The paper presented here is substantially based on the most recent classification of odontogenic and maxillofacial tumours (5th edition, 2022) which serves as a scaffold for the selection of typical tumour entities. Due to the educational character of this paper, only important jaw tumours worth mentioning and their characteristics are subject to be extracted from the literature and further discussed.The main focus was put onto both the description of radiological tumoral appearance and the rational selection of a radiological diagnostic work-up. In order to better visualize this difficult field of tumour entities, much attention has been paid on a comprehensive pictorial essay.For radiologists, it is their foremast task to detect, describe, and to classify bone tumours of the jaw when they are found intentionally or accidentally, resp. A close co-operation with their clinical partners is of upmost importance to gain information about patient´s history and clinical presentation. It is readily reasonable that radiologists are mostly able to provide only a suggestion of the presented tumour entity but this expert opinion would be very helpful to further narrow down the list of potential differential diagnoses (e.g., differentiation of a cyst vs. solid tumour osteolysis, identification of jaw osteomyelitis vs. tumoral infiltration, recognizing of secondary tumour involvement of the jaw). · primary bone tumours of the jaw are very rare, moreover difficult to differentiate radiologically, and do need therefore histological proof;. · profound knowledge about tumour characteristics (location within the jaw, relationship to the tooth, bony destructive pattern) may allow a rough orientation and classification;. · matrix-forming tumours and dysplasias of the jaw facilitates their radiological differentiation and classification;. · in contrary, osteolyses should be thoroughly scrutinized for the more frequent gnathic cysts in differentiation of rather rare solid primary tumours;. · an interdisciplinary round-table discussion amongst well-experienced maxillofacial surgeons and specialized radiologists may be appropriate to avoid severe misinterpretations.. · Grieser T, Hirsch E, Tödtmann N. Tumours of the jaw bones - Part II. Fortschr Röntgenstr 2024; DOI 10.1055/a-2416-1282.

Positron Emission Tomography-Computed Tomography and Magnetic Resonance Imaging Assessments in a Mouse Model of Implant-Related Bone and Joint Staphylococcus aureus Infection

Osteomyelitis is an infection of the bone, associated with an inflammatory process. Imaging plays an important role in establishing the diagnosis and the most appropriate patient management. However, data are lacking regarding the use of preclinical molecular imaging techniques to assess osteomyelitis progression in experimental models. This study aimed to compare structural and molecular imaging to assess disease progression in a mouse model of implant-related bone and joint infections caused by Staphylococcus aureus. In SWISS mice, the right femur was implanted with a resorbable filament impregnated with S. aureus (infected group, n = 10) or sterile culture medium (uninfected group, n = 6). Eight animals (5 infected, 3 uninfected) were analyzed with magnetic resonance imaging (MRI) at 1, 2, and 3 weeks postintervention, and 8 mice were analyzed with [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)-computed tomography (CT) at 48 h and at 1, 2, and 3 weeks postintervention. In infected animals, CT showed bone lesion progression, mainly in the distal epiphysis, although some uninfected animals presented evident bone sequestra at 3 weeks. MRI showed a lesion in the articular area that persisted for 3 weeks in infected animals. This lesion was smaller and less evident in the uninfected group. At 48 h postintervention, FDG-PET showed higher joint uptake in the infected group than in the uninfected group (P = 0.025). Over time, the difference between groups increased. These results indicate that FDG-PET imaging was much more sensitive than MRI and CT for differentiating between infection and inflammation at early stages. FDG-PET clearly distinguished between infection and postsurgical bone healing (in uninfected animals) from 48 h to 3 weeks after implantation. IMPORTANCE Our results encourage future investigations on the utility of the model for testing different therapeutic procedures for osteomyelitis.