Diagnostic Accuracy of CBCT with Different Voxel Sizes and Intraoral Digital Radiography for Detection of Periapical Bone Lesions: An Ex-Vivo Study.

OBJECTIVES: This study sought to assess the diagnostic accuracy of cone beam computed tomography (CBCT) with different voxel sizes and intraoral digital radiography with photostimulable phosphor (PSP) plate for detection of periapical (PA) bone lesions. MATERIALS AND METHODS: In this ex vivo diagnostic study, one-millimeter defects were created in the alveolar sockets of 15 bone blocks, each with two posterior teeth. A no-defect control group was also included. Digital PA radiographs with PSP plates and CBCT scans with 200, 250 and 300µ voxel sizes were obtained. Four observers evaluated the possibility of lesion detection using a 5-point scale. Sensitivity, specificity, positive predictive value (PPV) and negative predicative value (NPV) were analyzed using one-way ANOVA and Tamhane's post hoc test. Kappa and weighted kappa statistics were applied to assess intraobserver and interobserver agreements. RESULTS: Cochrane Q test showed no significant difference between PSP and CBCT imaging modalities in terms of kappa and weighted kappa statistics (P=0.675). The complete sensitivity and complete NPV for 200 and 250 µ voxel sizes were higher than those of 300 µ voxel size and digital radiography (P<0.001). No significant difference was noted in other parameters among other imaging modalities (P=0.403). CONCLUSIONS: The results showed that high-resolution CBCT scans had higher diagnostic accuracy than PSP digital radiography for detection of artificially created PA bone lesions. Voxel size (field of view) must be taken into account to minimize patient radiation dose.

Internal carotid artery stenosis presenting as ipsilateral posterior cerebral artery ischaemic stroke: a lesson to be learnt.

A 71-year-old lady presented with a symptomatic left cerebral occipital lobe infarct. With a history of paroxysmal atrial fibrillation a cardioembolic source was initially postulated. Prior significant bleeding while anticoagulated precluded warfarin therapy. Further investigations revealed a critical left internal carotid stenosis with a persistent fetal origin of the left posterior cerebral artery. She was successfully treated surgically and suffered no further ischaemic events. Physicians encountering posterior circulation stroke should be aware of this potentially treatable important diagnosis.