Background/Objectives: Studies attempting to predict the development of severe respiratory failure in patients with a COVID-19 infection using machine learning algorithms have yielded different results due to differences in variable selection. We aimed to predict the development of severe respiratory failure, defined as the need for high-flow oxygen support, continuous positive airway pressure, or mechanical ventilation, in patients with COVID-19, using machine learning algorithms to identify the most important variables in achieving this prediction. Methods: This retrospective, cross-sectional study included COVID-19 patients with mild respiratory failure (mostly receiving oxygen through a mask or nasal cannula). We used XGBoost, support vector machines, multi-layer perceptron, k-nearest neighbor, random forests, decision trees, logistic regression, and naïve Bayes methods to accurately predict severe respiratory failure in these patients. Results: A total of 320 patients (62.1% male; average age, 54.67 ± 15.82 years) were included in this study. During the follow-ups of these cases, 114 patients (35.6%) required high-level oxygen support, 67 (20.9%) required intensive care unit admission, and 43 (13.4%) died. The machine learning algorithms with the highest accuracy values were XGBoost, support vector machines, k-nearest neighbor, logistic regression, and multi-layer perceptron (0.7395, 0.7395, 0.7291, 0.7187, and 0.75, respectively). The method that obtained the highest ROC-AUC value was logistic regression (ROC-AUC = 0.7274). The best predictors of severe respiratory failure were a low lymphocyte count, a high computed tomography score in the right and left upper lung zones, an elevated neutrophil count, a small decrease in CRP levels on the third day of admission, a high Charlson comorbidity index score, and a high serum procalcitonin level. Conclusions: The development of severe respiratory failure in patients with COVID-19 could be successfully predicted using machine learning methods, especially logistic regression, and the best predictors of severe respiratory failure were the lymphocyte count and the degree of upper lung zone involvement.

Objective: Symmetrical bilateral lower extremity edema (BLEE) needs to be treated effectively. Finding the cause of this condition increases the success of treatment. Fluid increase in the interstitial space (FIIS) is always present as a cause or a result. Subcutaneously administered nanocolloid is transported by uptake by lymphatic pre-collectors, and this uptake takes place in the interstitium. We aimed to evaluate the interstitium with labeled nanocolloid and contribute to the differential diagnosis in cases with BLEE. Methods: Our retrospective study included 74 female patients who underwent lymphoscintigraphy for bilateral lower extremity edema. Technetium 99m (Tc-99m) albumin colloid (nanocolloid), a marked colloidal suspension, was applied subcutaneously to two different areas on the dorsum of both feet with a 26 gauge needle The dose volume administered intradermally is approximately 0.2-0.3 ml, and each injector has 22-25MBq of activity. Siemens E-Cam dual-headed SPECT gamma camera was used for imaging. Dynamic and scanning images were taken with a high-resolution parallel hole collimator. Ankle images were re-evaluated by two nuclear medicine specialists, independent of physical examination and scintigraphy findings. Results: 74 female patients with bilateral lower extremity edema were divided into two groups based on physical examination and lymphoscintigraphy findings. There were 40 and 34 patients in Groups I and II, respectively. In the physical examination, patients in Group I were evaluated as lymphedema, and patients in Group II were evaluated as lipedema. The main lymphatic channel (MLC) was not observed in any of the patients in Group I in the early images, and the MLC was observed at a low level in the late imaging in 12 patients. The sensitivity of the presence of distal collateral flows (DCF) in the presence of significant MLC in early imaging in demonstrating increased fluid in the interstitial space (FIIS) was calculated as 80%, specificity as 80%, PPV 80%, and NPV 84%. Conclusion: While MLC is present in early images, concomitant DCF occurs in cases of lipoedema. The transport of increased lymph fluid production in this group of patients can be covered by the existing MLC. Although MLC is evident, the presence of significant DCF supports the presence of lipedema. It can be used as an important parameter in the diagnosis in early cases where physical examination findings are not evident.

Objective: We aimed to evaluate the effectiveness of high-dose and low-dose use of radioactive material in intraoperative gamma probe application methods in patients diagnosed with primary hyperparathyroidism and planned for surgery. Methods: 47 patients with primary hyperparathyroidism underwent minimally-invasive parathyroid surgery (MIS) after preoperative imaging studies consisting of ultrasonography (USG) and sestamibi parathyroid scintigraphy (SPS) showed a possible primary parathyroid lesion (PPL). All patients received Tc-99 sestamibi on day-of-surgery imaging (DOSI) to help with the localization of a primary parathyroid lesion (PPL) via both DOSI and intraoperative gamma probe (IGP). Patients in Group I were administered 20-25 mCi Tc-99m sestamibi (methoxy isobutyl isonitrile) and images were obtained at the 20th and 120th minutes. Patients in Group II were administered 8-10 mCi doses and images were obtained at the 20th and 40th minutes. Two nuclear medicine specialists independently evaluated the images. Lesions in the localizations determined by DOSI and IGP were compared with the histopathological results of these lesions. Results: 47 patients, 35 females, and 12 males were included in the study. The mean age of 28 patients in the first group given the high dose was 54 (41-60), and the mean age was 48 (42-57) in the second group given the low dose (p=0.011). In the group given low-dose radioactive material during intraoperative gamma probe application, the observer's sensitivity, specificity, positive, and negative predictive values for finding pathology were 61.1, 100, 100, and 12.5, respectively. In the group given high-dose radioactive material, the same values were 90.9, 33.3, 50, and 83.3, respectively. While the success of MIS increases with the use of DOSI and IGP in large lesions, the success decreases with the prolongation of the accumulation time of the given dose. Conclusions: In the intraoperative gamma probe technique used in primary hyperparathyroidism patients, the method used with low-dose radioactive material has lower sensitivity but higher specificity in estimating the post-operative pathology compared to the high-dose technique.

Objective: The presence of gastroparesis in patients with dyspepsia can be evaluated by gastric emptying scintigraphy. We aimed to evaluate gastroparesis with optimal solid gastric emptying scintigraphy and suboptimal liquid gastric emptying scintigraphy in euthyroid goiter patients with dyspepsia. Methods: We included 67 patients diagnosed with euthyroid goiter with dyspepsia complaints. The patients did not use any medication and did not have any other chronic diseases. Solid and liquid gastric emptying scintigraphy was performed on all patients. In our retrospective study; the images were reevaluated. The region of interest was plotted on the area compatible with the stomach and timeactivity curves were obtained. The correlation of solid and liquid gastric emptying test results was evaluated. Results: Twelve (18%) of the patients were male and the mean age of the patients was 64 (49-75). There is a correlation between solid and liquid gastric emptying scintigraphy (p< 0.0005, r: 0.0880). Solid gastric emptying time was prolonged in 27 patients (40%). Liquid gastric emptying was prolonged in 23 patients (34%). Solid gastric emptying was also prolonged in all patients with prolonged liquid gastric emptying. Conclusion: According to the results of the optimal gastric emptying test performed with radio-labeled solid food. The rate of gastroparesis was low in our patient group with dyspepsia complaints. However, there is a correlation between the optimal test and suboptimal gastric emptying test results in our patient group. Liquid gastric emptying scintigraphy may be preferred in specific patient groups in case of suspected gastroparesis because of its easy application and short duration.

Objective: This study aims to evaluate the perfusion in the affected brain lobes with radionuclide imaging in patients with dementia and to contribute to the literature by determining the relationship between the degree of dementia. Methods: In this retrospective study, 44 adult patients were included. The mean age of the patients was 73 (57-87). Twenty-three (52.3%) of these were female. All patients underwent mini-mental state test, neurological examinations and radionuclide brain perfusion imaging. The areas of interest of the frontal, parietal, temporal, and occipital lobes and the cerebellum were drawn, respectively, and the cerebellum ratios of the relevant lobes were compared. In this way, brain perfusion index values of lobes were obtained. Results: Brain perfusion in group 1 was higher than in other groups. Groups were also compared in pairs. There was no significant difference in perfusion values in the occipital lobe. There was a significant difference in perfusion between groups 1 and 2 in lobes other than the occipital lobe. This was also the case for Groups 1 and 3. When group 2 with early dementia symptoms, and group 3 with moderate dementia were compared, there was a significant difference between the perfusion values of only the right and left frontal lobes. Conclusion: Early diagnosis is very important in progressive dementia. Clinical tests are successfully applied to categorize patients. Evaluation of brain perfusion and metabolism with functional radionuclide imaging is significant in guiding the treatment and evaluating the success of the treatment.