Objective:   This study aimed to evaluate the changes in upper airway (UA) dimensions in growing patients with Pierre-Robin sequence (PRS). Methods: The subjects were 23 PRS patients who had not undergone growth modification therapy or surgical intervention. Their lateral cephalograms were obtained longitudinally at mean ages of 8.81 (T0) and 14.05 (T1). Patients were categorized based on their SNB value at T0 (Criteria: –2 SD): Group-1 (very retrusive mandible, n = 13) and Group-2 (moderately retrusive mandible, n = 10). Skeletal and UA variables at T0 and T1, as well as ∆T0-T1, were statistically analyzed. Results: At T0, Group-1 exhibited more retrusive maxilla and mandible (SNA, P < 0.01; SNB, P < 0.001), a more hyperdivergent pattern (facial height ratio, P < 0.05), and a more posteriorly positioned hyoid bone (H-PTV, P < 0.05), while Group-1 showed larger UA spaces (superior pharyngeal airway space [SPAS] and inferior pharyngeal airway space, all P < 0.05) than Group 2, which might indicate the existence of a compensatory response to maintain the UA patency.At T1, Group-1 maintained significantly retrusive maxilla and mandible (SNA and SNB, all P < 0.01), exhibited a less anteriorly positioned tongue (TT-PTV, P < 0.05), and displayed a more obtuse soft palate angle (SPA, P < 0.05) than Group-2.Between T0 and T1, Group-1 demonstrated significant increases in the hyoid symphysis distance (∆H-RGN, P < 0.001), tongue length (∆TGL, P < 0.01), and pharyngeal UA spaces (∆SPAS and ∆PNS-ad2, all P < 0.001). Conclusions Even in growing PRS patients with severe mandibular retrusion, the UA dimensions increased due to forward growth of the mandible, repositioning of tongue and hyoid bone, and existence of compensatory mechanism.

Objective: Using finite element method (FEM) analysis of a clear aligner (CA), this study aimed to investigate the effects of varying the edentulous space on canine distal bodily movement during space closure following maxillary first premolar extraction. Methods: FEM analysis was used to simulate distal canine bodily movement following maxillary first premolar extraction using CAs. Four CA designs for edentulous spaces were compared: no-pontic, full-pontic, halfpontic, and beam. Three-dimensional models of the tooth components and CA were created. The target was set at a 0.25-mm distal canine movement. Long-term tooth movement was simulated using an iterative calculation method. Results: All the groups initially showed crown displacement, distal tipping, and distal rotation.Over time, the movement patterns differed in relation to the design. The no-pontic design exhibited the greatest displacement and tipping. The beam design exhibited the largest initial displacement but showed the lowest displacement and tipping thereafter. Full- and half-pontic designs yielded intermediate results. Significant force reduction was observed immediately after CA application, and was followed by a gradual decrease. The mean tooth-movement achievement rate was approximately 76.7%. Conclusions The edentulous space design of the CA substantially affected tooth-movement behavior. An iterative simulation is necessary to evaluate longterm tooth-movement patterns. The beam design demonstrated optimal suitability for bodily movement with minimal tipping. For optimal results, additional setup or overcorrection may be necessary.

Objectives: To assess the trends and disparities in the utilization of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) in Korea between 2018 and 2022, with a focus on disease classification, patient demographics, and regional distribution. Methods: This national surveillance retrospective study uses data from the Health Insurance Review and Assessment Service (HIRA) database, which includes all FDG PET/CT examinations conducted in Korea from 2018 to 2022. Disease classifications, cancer types, age groups, gender, and geographic regions were analyzed using descriptive statistics. Utilization rates per 100,000 population were calculated for regional comparisons. Results: FDG PET/CT utilization increased by 25.4%, from 174,885 examinations in 2018 to 219,377 in 2022. Older age groups (60 years and above) accounted for the majority of examinations, with males undergoing more examinations than females. Oncology remained the primary indication, with lung, colorectal, and non-Hodgkin lymphoma leading in examination numbers. The number of examinations performed on patients aged 60 and above increased at a higher rate compared to those under 60. Significant geographic disparities were found, with Seoul reporting the highest utilization rate (1,114.3 examinations per 100,000 population), while Gyeongbuk exhibited much lower rate (26.2 examinations per 100,000 population). Conclusions This study highlights the growing utilization of FDG PET/CT in Korea, particularly among older adults, with significant gender differences in cancer types. The findings also reveal disparities in FDG PET/CT utilization across regions, indicating varying access to advanced imaging technology.

Purpose: 11C-Methionine PET/CT is a promising method for detecting parathyroid lesions in patients with primary hyperparathyroidism (PHPT). We aimed to determine the diagnostic ability and correlation of digital 11C-Methionine PET/CT for parathyroid lesions in patients with PHPT, particularly in cases where standard imaging methods yielded inconclusive results. Methods: This retrospective analysis was conducted on patients diagnosed with PHPT who underwent digital 11C-Methionine PET/CT imaging because of ambiguous results on standard imaging work-up ( 99m Tc-MIBI parathyroid scan and/or neck ultrasonography). Quantitative 11C-Methionine PET/CT parameters, including maximum standardized uptake value (SUVmax), mean SUV (SUVmean), peak SUV (SUVpeak), parathyroid methionine volume (PMV), and whole methionine uptake(WMU: PMV multiplied by SUVmean) were calculated with various thresholds, and their correlations with biochemical andpathologic parameters were investigated. Results: This study included 22 consecutive patients (10 men and 12 women) with a median age of 64.0 years. The lesion detection rate and sensitivity of digital 11C-Methionine PET/CT were 81.8% (18/22) and 100.0% (18/18), respectively.Quantitative analysis revealed that serum PTH (r = 0.490, P = 0.039) and serum calcium (r = 0.583, P = 0.011) were signifi-cantly correlated with PMV50%. Conclusion Digital 11C-Methionine PET/CT offers good performance in the detection of parathyroid lesions in PHPT patients with inconclusive standard imaging work-up. The volume parameter of PMV50% significantly correlated biochemi-cal parameters and can serve as a complementary diagnostic tool.

Ectopic thyroid is thyroid tissue found in places other than the anterolateral aspect of the second to fourth tracheal ring. Mediastinal ectopic thyroid is rare and only few cases have been reported. The authors experienced a case of 41-year-old female patient with an anterior neck mass. The patient had mild chest discomfort when breathing with no other symptoms. Imaging studies suggested tumor of thymic tissue origin and surgical excision was done. The mass was successfully removed and histopathologically determined to be thyroid tissue. We hereby report with a review of literature a case of ectopic thyroid found in the mediastinum, which was successfully removed by transcervical incision.

Objectives: To assess the trends and disparities in the utilization of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG PET/CT) in Korea between 2018 and 2022, with a focus on disease classification, patient demographics, and regional distribution. Methods: This national surveillance retrospective study uses data from the Health Insurance Review and Assessment Service (HIRA) database, which includes all FDG PET/CT examinations conducted in Korea from 2018 to 2022. Disease classifications, cancer types, age groups, gender, and geographic regions were analyzed using descriptive statistics. Utilization rates per 100,000 population were calculated for regional comparisons. Results: FDG PET/CT utilization increased by 25.4%, from 174,885 examinations in 2018 to 219,377 in 2022. Older age groups (60 years and above) accounted for the majority of examinations, with males undergoing more examinations than females. Oncology remained the primary indication, with lung, colorectal, and non-Hodgkin lymphoma leading in examination numbers. The number of examinations performed on patients aged 60 and above increased at a higher rate compared to those under 60. Significant geographic disparities were found, with Seoul reporting the highest utilization rate (1,114.3 examinations per 100,000 population), while Gyeongbuk exhibited much lower rate (26.2 examinations per 100,000 population). Conclusions This study highlights the growing utilization of FDG PET/CT in Korea, particularly among older adults, with significant gender differences in cancer types. The findings also reveal disparities in FDG PET/CT utilization across regions, indicating varying access to advanced imaging technology.

Purpose: 11C-Methionine PET/CT is a promising method for detecting parathyroid lesions in patients with primary hyperparathyroidism (PHPT). We aimed to determine the diagnostic ability and correlation of digital 11C-Methionine PET/CT for parathyroid lesions in patients with PHPT, particularly in cases where standard imaging methods yielded inconclusive results. Methods: This retrospective analysis was conducted on patients diagnosed with PHPT who underwent digital 11C-Methionine PET/CT imaging because of ambiguous results on standard imaging work-up ( 99m Tc-MIBI parathyroid scan and/or neck ultrasonography). Quantitative 11C-Methionine PET/CT parameters, including maximum standardized uptake value (SUVmax), mean SUV (SUVmean), peak SUV (SUVpeak), parathyroid methionine volume (PMV), and whole methionine uptake(WMU: PMV multiplied by SUVmean) were calculated with various thresholds, and their correlations with biochemical andpathologic parameters were investigated. Results: This study included 22 consecutive patients (10 men and 12 women) with a median age of 64.0 years. The lesion detection rate and sensitivity of digital 11C-Methionine PET/CT were 81.8% (18/22) and 100.0% (18/18), respectively.Quantitative analysis revealed that serum PTH (r = 0.490, P = 0.039) and serum calcium (r = 0.583, P = 0.011) were signifi-cantly correlated with PMV50%. Conclusion Digital 11C-Methionine PET/CT offers good performance in the detection of parathyroid lesions in PHPT patients with inconclusive standard imaging work-up. The volume parameter of PMV50% significantly correlated biochemi-cal parameters and can serve as a complementary diagnostic tool.

Ectopic thyroid is thyroid tissue found in places other than the anterolateral aspect of the second to fourth tracheal ring. Mediastinal ectopic thyroid is rare and only few cases have been reported. The authors experienced a case of 41-year-old female patient with an anterior neck mass. The patient had mild chest discomfort when breathing with no other symptoms. Imaging studies suggested tumor of thymic tissue origin and surgical excision was done. The mass was successfully removed and histopathologically determined to be thyroid tissue. We hereby report with a review of literature a case of ectopic thyroid found in the mediastinum, which was successfully removed by transcervical incision.

Objective:   This study aimed to evaluate the changes in upper airway (UA) dimensions in growing patients with Pierre-Robin sequence (PRS). Methods: The subjects were 23 PRS patients who had not undergone growth modification therapy or surgical intervention. Their lateral cephalograms were obtained longitudinally at mean ages of 8.81 (T0) and 14.05 (T1). Patients were categorized based on their SNB value at T0 (Criteria: –2 SD): Group-1 (very retrusive mandible, n = 13) and Group-2 (moderately retrusive mandible, n = 10). Skeletal and UA variables at T0 and T1, as well as ∆T0-T1, were statistically analyzed. Results: At T0, Group-1 exhibited more retrusive maxilla and mandible (SNA, P < 0.01; SNB, P < 0.001), a more hyperdivergent pattern (facial height ratio, P < 0.05), and a more posteriorly positioned hyoid bone (H-PTV, P < 0.05), while Group-1 showed larger UA spaces (superior pharyngeal airway space [SPAS] and inferior pharyngeal airway space, all P < 0.05) than Group 2, which might indicate the existence of a compensatory response to maintain the UA patency.At T1, Group-1 maintained significantly retrusive maxilla and mandible (SNA and SNB, all P < 0.01), exhibited a less anteriorly positioned tongue (TT-PTV, P < 0.05), and displayed a more obtuse soft palate angle (SPA, P < 0.05) than Group-2.Between T0 and T1, Group-1 demonstrated significant increases in the hyoid symphysis distance (∆H-RGN, P < 0.001), tongue length (∆TGL, P < 0.01), and pharyngeal UA spaces (∆SPAS and ∆PNS-ad2, all P < 0.001). Conclusions Even in growing PRS patients with severe mandibular retrusion, the UA dimensions increased due to forward growth of the mandible, repositioning of tongue and hyoid bone, and existence of compensatory mechanism.

Objective: Using finite element method (FEM) analysis of a clear aligner (CA), this study aimed to investigate the effects of varying the edentulous space on canine distal bodily movement during space closure following maxillary first premolar extraction. Methods: FEM analysis was used to simulate distal canine bodily movement following maxillary first premolar extraction using CAs. Four CA designs for edentulous spaces were compared: no-pontic, full-pontic, halfpontic, and beam. Three-dimensional models of the tooth components and CA were created. The target was set at a 0.25-mm distal canine movement. Long-term tooth movement was simulated using an iterative calculation method. Results: All the groups initially showed crown displacement, distal tipping, and distal rotation.Over time, the movement patterns differed in relation to the design. The no-pontic design exhibited the greatest displacement and tipping. The beam design exhibited the largest initial displacement but showed the lowest displacement and tipping thereafter. Full- and half-pontic designs yielded intermediate results. Significant force reduction was observed immediately after CA application, and was followed by a gradual decrease. The mean tooth-movement achievement rate was approximately 76.7%. Conclusions The edentulous space design of the CA substantially affected tooth-movement behavior. An iterative simulation is necessary to evaluate longterm tooth-movement patterns. The beam design demonstrated optimal suitability for bodily movement with minimal tipping. For optimal results, additional setup or overcorrection may be necessary.