The validity of SPECT/CT in diagnosis of condylar hyperplasia

Diagnostic accuracy of bone SPECT and SPECT/CT imaging in the diagnosis of unilateral condylar hyperplasia: A systematic review and meta-analysis

Imaging with bone scans plays an important role in the diagnostic path of patients with unilateral condylar hyperactivity or unilateral condylar hyperplasia (UCH). The aim of this study is to perform a systematic review of the diagnostic performance of the bone SPECT and SPECT/CT scan for the diagnosis of UCH. PubMed, SCOPUS and EMBASE were searched electronically to identify diagnostic accuracy studies that assessed the diagnostic value of bone SPECT and SPECT/CT for the diagnosis of UCH, Meta-analyses were performed with Metadisc 1.4 and 2.0. A total of 14 studies, with a total number of 887 patients, were included in the qualitative analysis and 11 studies qualified for meta-analyses. The pooled sensitivity and specificity for the SPECT scan were 0.814 (95 % CI: 0.639-0.915) and 0.774 (95 % CI: 0.655-0.861), for the SPECT/CT scan these were 0.818 (95 % CI: 0.749-0.874) and 0.901 (95 % CI: 0.840-0.945). The summary receiver operating characteristics of the SPECT scan showed an area under the curve of 0.847 (95 % CI: 0.722-0.972) and that of the SPECT/CT scan was 0.928 (95 % CI: 0.876-0.980). CONCLUSION: Both bone SPECT scan and SPECT/CT scan provide a high diagnostic accuracy for UCH. The added value of the SPECT/CT scan is questionable and given the potential disadvantages of the SPECT/CT scan, including the increased radiation dose and costs, the diagnostic modality of first choice in patients with UCH should be a SPECT scan.

Unilateral Condylar Hyperplasia With Active Bony Overgrowth: A Case Report

Condylar hyperplasia (CH) is an overgrowth disorder of the temporomandibular joint bones caused by growth center overactivity of the mandibular condyle. Although the disorder is mostly idiopathic, several etiologies have been proposed. CH presents as progressive facial asymmetry with functional abnormalities. A combination of clinical, histopathological, and radiological findings is crucial to determine the diagnosis. Several diagnostic algorithms have been described in the literature. Management of CH is variable and depends on the growth of the bone. Here, we present the case of a 36-year-old female who presented with progressive facial asymmetry which was diagnosed as unilateral CH with active bony overgrowth.

SPECT/CT Correlation in the Diagnosis of Unilateral Condilar Hyperplasia

Objective: To evaluate the correlation between metabolic bone activity measured by single photon emission computed tomography (SPECT) and the anatomic condylar characteristics acquired by computed tomography (CT), in patients with unilateral condylar hyperplasia (UCH). Method and Materials/Patients: Observational, descriptive study in a group of 71 patients with clinical diagnosis of UCH and indication of SPECT/CT. Bone SPECT images obtained in a gamma-camera GE Infina and processed in a station Xeleris 3 with the program Volumetrix MI Evolution for bone. CT images acquired in a PET/CT Biograph mcT20 equipment (Siemens) processed in a station Osirix V 7.5.1 (Pixmeo, Bomex, Switzerland). Results: The sample included 24 men (33.8%) and 47 women (66.2%). Active state UCH was detected in 40 (56.3%) cases (over 55% uptake in the affected condyle) and 38 (53.5%) presented mandibular deviation to the right side. No significant differences related to sex, age, or mandibular deviation side were found. Mandibular deviation was the only morphologic feature related to active/inactive UCH (p = 0.003). The likelihood of active CH was significantly higher in patients with mandibular deviation higher than 6 mm compared with <6 mm (odds ratio (OR): 3.51, confidence interval (CI) 95%: 1.27–9.72). Conclusion: There is a significant correlation between the magnitude of mandibular deviation quantified on CT and metabolic findings obtained by SPECT in patients with UCH. The risk of active UCH is 3.5 times higher in patients with a mandibular deviation ≥6 mm.

Utility of Single-Photon Emission Computed Tomography/Computed Tomography in Suspected Unilateral Condylar Hyperplasia: A Histopathologic Validation Study

PURPOSE

The purpose of this study is to evaluate the utility of hybrid single-photon emission computed tomography (SPECT) and computed tomography (CT) with technetium-99m methylene diphosphonate in patients with suspected active unilateral condylar hyperplasia (UCH) using histopathology as the reference standard.

METHODS

Twenty-four patients with suspected active UCH prospectively underwent technetium-99m methylene diphosphonate planar bone scintigraphy with SPECT/CT of the mandible. Qualitative and quantitative readings for growth activity were performed by 3 nuclear medicine physicians and the final diagnosis was derived from postoperative histopathological examination. Readings were reported as positive, equivocal, or negative. Total, maximum, and mean counts were recorded for each condyle on SPECT/CT images. The uptake of the index (suspected) condyle was expressed as a count ratio (R_total, R_mean, R_max), a percentage uptake (P_total, P_mean, P_max), background-corrected counts (B_total, B_mean, B_max), as well as CT-based condylar diameters (R_CT,P_CT) relative to the contralateral condyle.

RESULTS

Interobserver agreement was 0.79 and 0.83 for planar bone scintigraphy and SPECT/CT, respectively, with a total of 5 and 1 equivocal readings from the respective modalities. Surgery was performed in 22 patients; all of them had pathologically proven UCH. SPECT/CT was slightly more sensitive than planar bone scintigraphy (91 vs 78%) with identical specificity (96%). R_total, R_mean, P_total, and P_mean demonstrated area under the curve between 84% and 86%. Metrics based on CT diameters and background-corrected counts were not associated with UCH diagnosis.

CONCLUSIONS

Quantitative approaches based on total or mean count ratio or relative count percentage were equally predictive for UCH diagnosis; however, they were slightly less sensitive compared with qualitative technetium-99m methylene diphosphonate SPECT/CT evaluation. SPECT/CT evaluation has the potential to decrease the equivocal readings.