Radiological evaluation of maxillary sinusitis and temporal bone structures

Background: In the field of otorhinolaryngology, the paranasal sinuses and the middle and inner ear present a clinical challenge. Radiological methods offer a stable foundation for diagnostics and preoperative decisions in this context. While many studies have explored the prevalence of maxillary sinusitis of dental origin (MSDO), the use of MSDO detected on cone beam computed tomography (CBCT) scans, rather than conventional computed tomography (CT), is a relatively new approach to detect MSDO. CBCT, with its higher ability to assess bony details, is becoming a valuable tool in detecting MSDO. Photon-counting Computed Tomography (PCCT), a cutting-edge diagnostic imaging method, enables radiological examinations with high spatial resolution at a low radiation dose compared with conventional CT. However, the question of how much the dose can be reduced while maintaining still diagnostic value in radiological examinations remains unanswered. Aims: This thesis aimed to further develop the use of radiology in the ear, nose and throat (ENT) medical field, which could impact how we interpret radiological findings to obtain useful clinical information. The objectives for this thesis were as follows: 1) to investigate the proportion of MSDO among patients with suspected sinusitis referred for radiological examination; 2) to compare the symptomatology of MSDO with sinusitis due to upper respiratory tract infection (URTI); 3) to develop a modular anthropomorphic phantom that could be used to evaluate the performance of radiological techniques in detecting pathology in the temporal bone (TB) region; and 4) to investigate whether the diagnostic quality of TB imaging is maintained even at significantly lower radiation doses using PCCT compared to conventional energy integrated computed tomography (EICT). Material and methods: Paper I was a retrospective study in which our research team reviewed 303 CBCT sinus examinations and analysed the data to determine the prevalence of MSDO among patients with suspected sinusitis who had been referred for radiological examination.A retrospective study was conducted in Paper II, in which the medical records from 61 patients with maxillary sinusitis confirmed via CBCT were thoroughly reviewed. Two independent observers reviewed all cases; when the observers disagreed, the examinations were re-reviewed to reach a consensus, ensuring the reliability of the findings. For comparison, the patients were divided into MSDO and URTI sinusiti