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To develop a modular anthropomorphic phantom to evaluate the performance of radiological techniques for detecting pathologies in the temporal bone region. A phantom was constructed using a human skull, temporal bone specimen, and 3D-printed contour of a human skull. The human skull was embedded in tissue-equivalent plastic, with a cavity to hold the plastic jars containing the exchangeable freshly frozen human temporal bones. Subsequently, stepwise introduction and examination of different clinicopathological scenarios were conducted. Radiological images were nearly identical to those acquired from patients using computed tomography (CT) and cone beam computed tomography (CBCT). The radiological attenuation of polyurethane plastic (PUR) and alginate were similar to those of the soft tissues of living human patients. The mean Hounsfield unit values of the CT slices representing tissue at the brain and temporal bone level were 184 and 171 in the phantom and patient groups, respectively. The modular phantom developed in this study can evaluate radiological techniques and diagnostic possibilities without exposing patients to radiation. To our knowledge, no such modular phantom has been reported in the literature or made available commercially.

Background: The value of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for TN staging in head and neck cancer (HNC) has been proven in numerous studies. A few studies have investigated the value of FDG-PET/magnetic resonance imaging (MRI) in the staging of HNC; the combined results indicate potential for FDG-PET/MRI, but the scientific evidence remains weak.

Purpose: To compare performance of FDG-PET/CT and FDG-PET/MRI for locoregional staging in patients with oropharyngeal carcinomas.

Material and Methods: Two radiologists independently of each other retrospectively reviewed primary pre-therapeutic FDG-PET/CT and FDG-PET/MRI examinations from 40 individuals with oropharyngeal carcinomas. TN stage and primary tumor size were noted. The results were compared between observers and modalities and against TN stage set at a multidisciplinary conference.

Results: For nodal staging, PET/MRI had slightly higher specificity and accuracy than PET/CT for the most experienced observer. Both methods demonstrated excellent sensitivity (≥ 0.97 and 1.00, respectively), as well as high negative predictive values (≥ 0.95 and 1.00, respectively). No significant differences were found for tumor staging or measurement of maximum tumor diameter. There was a weak agreement (κ = 0.35–0.49) between PET/CT and PET/MRI for T and N stages for both observers. Inter-observer agreement was higher for PET/MRI than for PET/CT, both for tumor staging (κ = 0.57 vs. 0.35) and nodal staging (κ = 0.69 vs. 0.55). The agreement between observers was comparable to the agreement between methods.

Conclusion: PET/MRI may be a viable alternative to PET/CT for locoregional staging (TN staging) and assessment of maximal tumor diameter in oropharyngeal squamous cell cancer.

Background: Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has been proven to be a good method to detect distant spread of head and neck cancer (HNC). However, most prior studies are based on Asian populations and may not be directly transferable to western populations.

Purpose: To investigate the frequency and distribution of distant metastases and synchronous malignancies detected by PET/CT in HNC in a northern Swedish population.

Material and Methods: All primary whole-body FDG-PET/CT examinations performed on the suspicion of HNC (n = 524 patients) between 1 January 2013 and 31 December 2016 at Umeå University Hospital in Sweden were retrospectively reviewed . After the exclusion of 189 examinations without evidence of primary HNC, 335 examinations were analyzed.

Results: Distant metastases were detected in 10 (3%) patients, all with advanced primary tumors corresponding to TNM stage 3–4, most frequently in salivary gland adenocarcinoma, where 50% of patients had distant spread. Four patients had metastases below the diaphragm, representing 20% of the salivary gland malignancies. In the remaining six patients, metastases were supraphrenic, of which all but one were identified by CT alone. Synchronous malignancies were discovered in 14 (4.2%) patients, of which five were below the diaphragm.

Conclusion: The overall frequency of distant spread and synchronous malignancy in primary HNC was generally low. However, the risk for distant metastases below the diaphragm was relatively higher in salivary gland adenocarcinoma, supporting whole-body FDG-PET/CT in the primary diagnostic work-up in these patients.

Objectives: To compare the symptomatology of patients with maxillary sinusitis of dental origin (MSDO) with sinusitis due to upper respiratory tract infection (URTI) with a special focus on time to correct diagnosis. To define the accuracy of cone beam computed tomography (CBCT) in detecting the dental origin of the sinusitis.

Methods: Retrospective review of the otolaryngology specialist care, primary health care and dental health care medical records of patients with maxillary sinusitis who has been referred for radiology. All patients were examined by CBCT, which has a better resolution regarding bony structures than low-dose computed tomography. To the best of our knowledge there is no previous study on this topic based on CBCT as diagnostic method.

Results: Sixty-one patients were included in the study; of these, 25 had MSDO and 36 had URTI sinusitis. The MSDO patients more frequently reported foul odour and foul taste than patients with URTI sinusitis. The URTI sinusitis patients more frequently reported symptoms such as facial pain, facial congestion and cold-related symptoms. Both the time from the onset of symptoms to the first medical visit and the subsequent time to a correct diagnosis were significantly longer in the MSDO group. The accuracy of CBCT for detecting dental pathology as the underlying cause of sinusitis was 97%.

Conclusion: The present study verifies that maxillary sinusitis of dental origin differs from viral-induced rhinosinusitis concerning symptomatology and clinical findings. Certain findings and symptoms could serve as valuable indicators of an underlying dental pathology, because although MSDO is well known, the present study shows that these patients are often misdiagnosed and the correct diagnose and treatment is often delayed several months. Consequently, better assessment is important. The suspicion of MSDO should be raised for patients with unilateral sinusitis presenting little pain, foul odour or foul taste and a long time course. These patients should be referred for radiology, preferably CBCT, to rule out odontogenic cause. CBCT is easy to perform for sinusitis examinations and has advances to common CT, especially regarding detection of pathology in bony structures as the periapical area. Because of this CBCT is a reliable tool in order to detect maxillary sinusitis of dental origin.

Aim: To gain insight into the decision processes of dentists when requesting a cone beam computed tomography (CBCT) examination in endodontic settings.

Methodology: Fourteen dentists (eight female) 33-58 years of age (mean = 44) practising in Sweden were interviewed. Ten of the dentists were specialists in Endodontics. The absolute inclusion criterion was experience of referring patients for CBCT for endodontic reasons. The included dentists comprised a strategically selected diverse sample in terms of gender, age, work experience, educational background, location of practice, service affiliation and accessibility to CBCT. Data were obtained through semistructured interviews exposing the context of their last three self-reported referrals. Dentists were encouraged to describe their experiences of the circumstances in their own words, aided by the interviewer's open-ended questions. The interviews were audio-recorded and transcribed verbatim. The text was analysed by qualitative content analysis.

Results: The manifest content was organized into three categories that were defined as visualization as a desire, facilitating tough decisions and allocating responsibility.

Conclusion: An overall theme (covering the latent content) was identified: A balance between clinical common sense and a 'better safe than sorry' attitude guides the use of CBCT in endodontic settings. Informants had high clinical standards, knowledge concerning radiation risks and good sense, which could compensate for their lack of knowledge of guidelines. The national radiation regulatory system was perceived to work as a slightly porous gatekeeper for over-usage.

Objectives: This study sought to investigate the proportion of patients with suspected sinusitis referred for radiological examination who have radiologically verified sinusitis of odontogenic origin and to describe this type of sinusitis. Study Design: This investigation is a retrospective study. Methods: A total of 303 sinus examinations involving cone beam computed tomography (CBCT) performed at Sunderby Hospital, Lulea, Sweden in 2012 were independently reviewed by two radiologists. The number of cases of maxillary sinusitis and the correlation between maxillary sinusitis and odontogenic infections were determined. Results: Overall, 24% of the verified cases of sinusitis were odontogenic. An odontogenic origin was identified in 40% of unilateral maxillary sinusitis cases but only 6% of bilateral maxillary sinusitis cases (p=0.0015). Forty-nine out of 54 patients with periapical destruction had adjacent mucosal swelling in the maxillary sinus, but only 15 of these patients satisfied the criteria for sinusitis. Conclusion: The present study confirms the close relationship between odontogenic infections and unilateral maxillary sinusitis.

Aim To determine whether the outcome of cone beam computed tomography (CBCT) examinations performed in accordance with the European Commission guidelines in a clinical setting has an impact on choosing diagnoses in endodontics. Methodology A prospective observational study was conducted. Fifty-three consecutive patients (81 teeth) from two different endodontic specialist clinics in Sweden were followed. After performing a thorough clinical examination (based on the history, clinical findings, and diagnostic tests such as intra-oral radiography), the examiner wrote down a preliminary diagnosis before CBCT examination. After the CBCT examination, a new diagnosis was made by the same examiner. Both the pre- and the post-CBCT examination diagnoses were plotted according to patients and teeth. The CBCT examinations were performed using similar equipment and protocols that were standardized amongst the clinics. Results The diagnoses were changed for at least one tooth in 22 patients (41%); overall, the diagnoses were changed for 28 teeth (35%). Conclusion CBCT has a substantial impact on diagnostic thinking in endodontics when used in accordance with the European Commission guidelines.

Objectives: The aim was to assess to what extent cone beam CT (CBCT) used in accordance with current European Commission guidelines in a normal clinical setting has an impact on therapeutic decisions in a population referred for endodontic problems.

Methods: The study includes data of consecutively examined patients collected from October 2011 to December 2012. From 2 different endodontic specialist clinics, 57 patients were referred for a CBCT examination using criteria in accordance with current European guidelines. The CBCT examinations were performed using similar equipment and standardized among clinics. After a thorough clinical examination, but before CBCT, the examiner made a preliminary therapy plan which was recorded. After the CBCT examination, the same examiner made a new therapy plan. Therapy plans both before and after the CBCT examination were plotted for 53 patients and 81 teeth. As four patients had incomplete protocols, they were not included in the final analysis.

Results: 4% of the patients referred to endodontic clinics during the study period were examined with CBCT. The most frequent reason for referral to CBCT examination was to differentiate pathology from normal anatomy, this was the case in 24 patients (45% of the cases). The primary outcome was therapy plan changes that could be attributed to CBCT examination. There were changes in 28 patients (53%).

Conclusions: CBCT has a significant impact on therapeutic decision efficacy in endodontics when used in concordance with the current European Commission guidelines.