Survey on chest CT findings in COVID-19 patients in Okinawa, Japan: differences between the delta and omicron variants.

To investigate the frequency of pneumonia and chest computed tomography (CT) findings in patients with coronavirus disease 2019 (COVID-19) during the fifth Delta variant-predominant and sixth Omicron variant-predominant waves of the COVID-19 pandemic in Okinawa, Japan. A survey on chest CT examinations for patients with COVID-19 was conducted byhospitals with board-certified radiologists who provided treatment for COVID-19 pneumonia in Okinawa Prefecture. Data from 11 facilities were investigated. Indications for chest CT; number of COVID-19 patients undergoing chest CT; number of patients with late-onset pneumonia, tracheal intubation, and number of deaths; and COVID-19 Reporting and Data System classifications of initial chest CT scans were compared by the chi-squared test between the two pandemic waves (Delta vs. Omicron variants). A total of 1944 CT scans were performed during the fifth wave, and 1178 were performed during the sixth wave. CT implementation rates, which were the number of patients with COVID-19 undergoing CT examinations divided by the total number of COVID-19 cases in Okinawa Prefecture during the waves, were 7.1% for the fifth wave and 2.1% for the sixth wave. The rates of tracheal intubation and mortality were higher in the fifth wave. Differences between the distributions of the CO-RADS classifications were statistically significant for the fifth and sixth waves (p < 0.0001). In the fifth wave, CO-RADS 5 (typical of COVID-19) was most common (65%); in the sixth wave, CO-RADS 1 (no findings of pneumonia) was most common (50%). The finding of "typical for other infection but not COVID-19" was more frequent in the sixth than in the fifth wave (13.6% vs. 1.9%, respectively). The frequencies of pneumonia and typical CT findings were higher in the fifth Delta variant-predominant wave, and nontypical CT findings were more frequent in the sixth Omicron variant-predominant wave of the COVID-19 pandemic in Okinawa, Japan.

Chronic thromboembolic pulmonary hypertension is associated with a loss of total lung volume on computed tomography.

BACKGROUND: Although lung volumes are usually normal in individuals with chronic thromboembolic pulmonary hypertension (CTEPH), approximately 20%-29% of patients exhibit a restrictive pattern on pulmonary function testing. AIM: To quantify longitudinal changes in lung volume and cardiac cross-sectional area (CSA) in patients with CTEPH. METHODS: In a retrospective cohort study of patients seen in our hospital between January 2012 and December 2019, we evaluated 15 patients with CTEPH who had chest computed tomography (CT) performed at baseline and after at least 6 mo of therapy. We matched the CTEPH cohort with 45 control patients by age, sex, and observation period. CT-based lung volumes and maximum cardiac CSAs were measured and compared using the Wilcoxon signed-rank test and the Mann-Whitney u test. RESULTS: Total, right lung, and right lower lobe volumes were significantly reduced in the CTEPH cohort at follow-up vs baseline (total, P = 0.004; right lung, P = 0.003; right lower lobe; P = 0.01). In the CTEPH group, the reduction in lung volume and cardiac CSA was significantly greater than the corresponding changes in the control group (total, P = 0.01; right lung, P = 0.007; right lower lobe, P = 0.01; CSA, P = 0.0002). There was a negative correlation between lung volume change and cardiac CSA change in the control group but not in the CTEPH cohort. CONCLUSION: After at least 6 mo of treatment, CT showed an unexpected loss of total lung volume in patients with CTEPH that may reflect continued parenchymal remodeling.

Factors associated with bone thickness: Comparison of the cranium and humerus.

Cortical bone thickness is important for the mechanical function of bone. Ontogeny, aging, sex, body size, hormone levels, diet, behavior, and genetics potentially cause variations in postcranial cortical robusticity. However, the factors associated with cranial cortical robusticity remain poorly understood. Few studies have examined cortical robusticity in both cranial and postcranial bones jointly. In the present study, we used computed tomography (CT) images to measure cortical bone thicknesses in the cranial vault and humeral diaphysis. This study clearly showed that females have a greater cranial vault thickness and greater age-related increase in cranial vault thickness than males. We found an age-related increase in the full thickness of the temporal cranial vault and the width of the humeral diaphysis, as well as an age-related decrease in the cortical thickness of the frontal cranial vault and the cortical thickness of the humeral diaphysis, suggesting that the mechanisms of bone modeling in cranial and long bones are similar. A positive correlation between cortical indices in the cranial vault and humeral diaphysis also suggested that common factors affect cortical robusticity. We also examined the association of polymorphisms in the WNT16 and TNFSF11 genes with bone thickness. However, no significant associations were observed. The present study provides fundamental knowledge about similarities and differences in the mechanisms of bone modeling between cranial and postcranial bones.

Radiomics analysis for differentiating of cervical lymphadenopathy between cancer of unknown primary and malignant lymphoma on unenhanced computed tomography.

To investigate the usefulness of texture analysis to discriminate between cervical lymph node (LN) metastasis from cancer of unknown primary (CUP) and cervical LN involvement of malignant lymphoma (ML) on unenhanced computed tomography (CT). Cervical LN metastases in 17 patients with CUP and cervical LN involvement in 17 patients with ML were assessed by 18F-FDG PET/CT. The texture features were obtained in the total cross-sectional area (CSA) of the targeted LN, following the contour of the largest cervical LN on unenhanced CT. Values for the max standardized uptake value (SUVmax) and the mean SUV value (SUVmean), and 34 texture features were compared using a Mann-Whitney U test. The diagnostic accuracy and area under the curve (AUC) of the combination of the texture features were evaluated by support vector machine (SVM) with nested cross-validation. The SUVmax and SUVmean did not differ significantly between cervical LN metastases from CUP and cervical LN involvement from ML. However, significant differences of 9 texture features of the total CSA were observed (p = 0.001 - 0.05). The best AUC value of 0.851 for the texture feature of the total CSA were obtained from the correlation in the gray-level co-occurrence matrix features. SVM had the best AUC and diagnostic accuracy of 0.930 and 84.8%. Radiomics analysis appears to be useful for differentiating cervical LN metastasis from CUP and cervical LN involvement of ML on unenhanced CT.

Proposal of a novel protocol using estimated cardiac index fractional dose to improve aortic contrast enhancement for early-phase dynamic CT.

ABSTRACT: Maximum aortic computed tomography value (CTV) is difficult to control because of variations in cardiac function and patient physique. Therefore, to improve early-phase aortic enhancement on dynamic computed tomography (CT), we developed an estimated cardiac index fractional dose (eciFD). The eciFD protocol is a novel and original protocol for administering fractional dose (FD), representing the amount of iodine per unit body weight per injection duration, based on cardiac index (cardiac output divided by body surface area) as estimated by age in early-phase dynamic CT. At the time of administration, by selecting FD based on the patient's age and selecting a parameter that can achieve this FD, an aortic CTV ≥300 HU (ACTV≥300) can be obtained. This study aimed to investigate aortic enhancement on CT angiography using the eciFD protocol.This retrospective study investigated 291 consecutive patients who underwent dynamic CT from neck to abdomen after recommendation of the eciFD protocol at our institution. We compared early-phase aortic CTV distributions by scan delay between an eciFD group (eciFD applied, n = 135) and a non-eciFD group (eciFD not applied, n = 80). The effect of eciFD on early-phase ACTV≥300 was evaluated using logistic regression analysis adjusted for several potentially meaningful clinical confounders related to aortic CTV, namely male sex, heart rate ≤80 beats/min, estimated glomerular filtration rate ≤40 mL/min, use of eciFD, bolus tracking (BT), history of myocardial infarction, and order from the emergency center.The eciFD protocol was a significant factor for early-phase ACTV≥300 after adjusting for several confounders (odds ratio 3.03; 95% confidence intervals 1.59-5.77; P = .001). No interaction was seen between BT and eciFD protocol (p for interaction = 0.76). In terms of CTV distribution, with both a fixed scan delay time and BT, the eciFD group showed a high aortic CTV. The combination of eciFD protocol with BT provided a particularly high percentage of patients with ACTV≥300 (86.4%).The eciFD protocol was useful for improving aortic contrast enhancement. These findings need to be validated in a randomized controlled study.

Efficacy of Pre-operative 18F-FDG PET/CT in Prognostic Prediction in Patients With Renal Cell Carcinoma.

Background/Aim: This study analyzed the parameters provided by preoperative 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for prognostic prediction of renal cell carcinoma (RCC). Patients and Methods: FDG-PET/CT data from 66 clear cell RCC and 19 non-clear cell RCC cases between January 2015 and October 2018 were reviewed retrospectively. We compared the two groups according to recurrence/metastasis to determine prognosis-influencing factors. Multivariate Cox hazard regression models were constructed to evaluate factors potentially predicting disease-free survival (DFS) after adjustment for confounders. DFS was then compared between groups. Results: Standardized uptake values (SUV) of the PET/CT scan were independent predictors of prognosis after adjusting for confounders. RCC cases were divided into two groups by optimal cut-off values. Differences between DFS percentages in high and low SUV groups were significant. Similar results were obtained in clear cell RCC groups. Conclusion: Increased SUV of the PET/CT scan are significant predictors of worse prognoses in patients with surgically resected RCC.

Therapeutic efficacy of selective intraarterial chemoradiotherapy with docetaxel and nedaplatin for human papilloma virus-negative oropharyngeal cancer.

OBJECTIVE: Human papilloma virus-negative oropharyngeal cancer has not achieved satisfactory outcomes compared with those of human papilloma virus-positive oropharyngeal cancer. This study evaluated the therapeutic efficacy of selective intraarterial chemoradiotherapy with the docetaxel and nedaplatin regimen for human papilloma virus-negative oropharyngeal cancer. METHODS: Twenty-two consecutive patients with human papilloma virus-negative oropharyngeal cancer who had undergone selective intraarterial chemoradiotherapy were retrospectively analyzed. The primary tumor and whole neck were irradiated (50 Gy). Subsequently, the primary site and metastatic lymph nodes were boosted by 20 Gy. The intraarterial chemotherapy regimen comprised a combination of nedaplatin (80 mg/m2) and docetaxel (60 mg/m2), which was initially administered at the start of radiotherapy and was given every 4 weeks for three sessions. Each intraarterial dose of an anticancer agent was determined according to the percentage of the tumor volume supplied by the target artery to the total tumor volume, which was intraoperatively measured via cone-beam computed tomography. The outcome measures were locoregional control, disease-free survival, and overall survival rates and adverse events. Statistical analyses were performed using the Kaplan-Meier method. RESULTS: The median follow-up period was 59 (range, 15-103) months. The T stage was T1/T2 in 5 patients (23%), T3 in 5 patients (23%), and T4 in 12 patients (54%). Cervical lymph node metastasis was staged as ≥N2c in 7 (32%) patients. Complete response was achieved in all patients at the first imaging examination after intraarterial chemoradiotherapy. The 5-year locoregional control, disease-free survival, and overall survival rates were 96% (95% confidence interval, 0.72-0.99), 91% (95% confidence interval, 0.68-0.98), and 100% (95% confidence interval, not available), respectively. Regarding serious acute adverse events, grade 4 laryngeal edema and leukopenia were observed in 1 (5%) and 11 patients (50%), respectively. No other serious acute adverse events were observed. CONCLUSION: Selective intraarterial chemoradiotherapy with docetaxel and nedaplatin has the potential to achieve favorable locoregional control, disease-free survival, and overall survival rates in human papilloma virus-negative oropharyngeal cancer.

Therapeutic efficacy of selective intra-arterial chemoradiotherapy with docetaxel and nedaplatin for fixed bulky nodal disease in head and neck cancer of unknown primary.

PURPOSE: Fixed bulky nodal disease in patients with head and neck cancer of unknown primary (HNCUP) remains difficult to treat. This retrospective study evaluated the therapeutic efficacy of selective intra-arterial chemoradiotherapy with docetaxel and nedaplatin for fixed bulky nodal disease in HNCUP. METHODS: Data from seven consecutive patients with fixed bulky nodal disease in HNCUP who had undergone selective intra-arterial chemoradiotherapy were analyzed. Whole pharyngeal mucosa and all bilateral nodal areas were irradiated (total dose 50 Gy), and bulky nodal lesions were provided an additional 20 Gy. Intra-arterial chemotherapy used a combination of nedaplatin (80 mg/m2) and docetaxel (60 mg/m2). Outcome measures were local control, disease-free survival, overall survival, and adverse events. Statistical analyses were performed using the Kaplan-Meier method. RESULTS: Median follow-up period was 24 months (range 9-64). All patients had extracapsular extension (N3b) on imaging and clinical findings. Symptoms due to bulky disease were neck discomfort (100%), tumor bleeding (43%), tracheal obstruction (14%), and carotid sinus syndrome (28%). Median value for maximum diameter of cervical disease was 84 mm (range 70-107), and 3-year local control, disease-free survival, and overall survival rates were 100, 54, and 64%, respectively. Symptoms due to bulky disease disappeared in all patients after intra-arterial chemoradiotherapy. Grade 4 leukopenia occurred in two patients (28%) as an acute adverse event. No other serious acute adverse events were observed. CONCLUSION: Selective intra-arterial chemoradiotherapy with docetaxel and nedaplatin can potentially achieve both favorable local control and survival in in HNCUP with fixed bulky nodal disease.

Kerley A-lines represent thickened septal plates between lung segments in patients with lymphangitic carcinomatosis: confirmation using 3D-CT lung segmentation analysis.

PURPOSE: Kerley A-lines are generally apparent in patients with pulmonary edema or lymphangitic carcinomatosis. There are two main thoughts regarding the etiology of Kerley A-lines, but no general agreement. Specifically, the lines are caused by thickened interlobular septa or dilated anastomotic lymphatics. Our purpose was to determine the anatomic structure represented as Kerley A-lines using 3D-CT lung segmentation analysis. MATERIALS AND METHODS: We reviewed 139 charts of patients with lymphangitic carcinomatosis of the lung who had CT and X-ray exams with a maximum interval of 7 days. The presence of Kerley A-lines on X-ray was assessed by a radiologist. The A-lines on X-ray were defined as follows: dense; fine (< 1 mm thick); ≥ 2 cm in length, radiating from the hilum; no bifurcation; and not adjacent to the pleura. For cases with Kerley A-lines on X-ray, three radiologists agreed that the lines on CT corresponded with Kerley A-lines. The incidence of A-lines and the characteristics of the lines were investigated. The septal lines between lung segments were identified using a 3D-CT lung segmentation analysis workstation. The percentage of agreement between the A-lines on CT and lung segmental lines was assessed. RESULTS: On chest X-ray, 37 Kerley A-lines (right, 16; left, 21) were identified in the 22 cases (16%). Of these, 4 lungs with 12 lines were excluded from analysis due to technical reasons. Nineteen of the 25 lines (76%) corresponded to the septal lines on CT. Of these, 11 lines matched with automatically segmented lines (intersegmental septa, 4; intersubsegmental septa, 7) by the workstation. Two lines (8%) represented fissures. Four lines corresponded to the bronchial wall/artery (3 lines, 12%) or vein (1 line, 4%). CONCLUSION: Kerley A-lines primarily represented thickened and continued interlobular septal lines that corresponded to the septa between lung segments and subsegments.

Patterns of recurrence after low-dose postoperative radiotherapy for head and neck squamous cell carcinoma.

BACKGROUND: Postoperative chemoradiotherapy is recommended for patients with head and neck squamous cell carcinoma with positive margins or extracapsular extension at high risk of recurrence. However, high-dose radiotherapy in the head and neck region often causes severe acute and late radiation-related adversities. In our institution, the radiation dose has been relatively lower than that used in Western countries to reduce radiation-related toxicities. Therefore, in this study, we examined the treatment outcomes of low-dose postoperative chemoradiotherapy. METHODS: The outcomes of 90 consecutive head and neck squamous cell carcinoma patients who received postoperative radiotherapy between June 2009 and December 2016 were retrospectively analyzed. All patients received postoperative three-dimensional conformal radiotherapy with or without concurrent systemic chemotherapy. The median patient age was 65 years. Concurrent chemoradiotherapy was administered at a total dose of 50.4 Gy in 28 fractions (daily fraction, 1.8 Gy). High-risk patients received 10.8 Gy of boost irradiation in six fractions. For radiotherapy alone, the irradiation dose was up to 54 Gy in 30 fractions and 64.8 Gy in 36 fractions for high-risk patients to increase the treatment intensity. RESULTS: The median follow-up period was 40.5 months. The 3-year locoregional control and overall survival rates were 67.5% and 82.7%, respectively. A significantly higher proportion of patients with oral cavity carcinoma experienced locoregional failure (p = 0.004). The acute adverse events were mild, and the only late adverse event was grade 3 dysphagia (n = 3). CONCLUSION: This study suggests that de-escalation of the postoperative radiation dose can potentially reduce the severe adverse events of irradiation in patients while ensuring its effectiveness. In patients with oral cavity carcinoma, it might be necessary to increase the radiation dose.

Computed tomography findings, temporal course, and clinical relevance of subpleural pulmonary interstitial emphysema in patients with pneumomediastinum.

BACKGROUND: Subpleural pulmonary interstitial emphysema is defined as the air in the subpleural portion of the lung, and the clinical relevance is not well understood. PURPOSE: to evaluate the frequency, temporal course, risk factors, and clinical significance of subpleural pulmonary interstitial emphysema (PIE) in patients with pneumomediastinum resulting from ruptured alveoli and other causes. MATERIAL AND METHODS: This was a retrospective study of 130 patients with pneumomediastinum on CT between January 2009 and December 2019 at 2 hospitals. Patients were divided into 3 groups as follows: spontaneous pneumomediastinum (n = 101), pneumomediastinum due to blunt trauma (n = 16), and pneumomediastinum due to another known cause (n = 13). The frequencies of radiographic features (subpleural PIE, peribronchovascular PIE, pneumothorax, pulmonary fibrosis, and emphysematous changes) between the 3 groups were compared by the χ2 or Kruskal-Wallis test. Odds ratios were calculated to evaluate candidate risk factors for subpleural and peribronchovascular PIE. RESULTS: Subpleural PIE was observed in 0%, 15.8%, and 31.3% of patients with pneumomediastinum due to another cause, spontaneous mediastinum, and blunt trauma, respectively. In most patients, subpleural PIE resolved spontaneously (85.7% within 8 days). Two patients with pulmonary fibrosis showed recurrent subpleural PIE on follow-up. Young age showed increased risk for subpleural PIE (odds ratio [OR] 0.9, 95% confidence interval [CI] 0-0.99). CONCLUSION: Subpleural PIE was only detected in patients with pneumomediastinum due to ruptured alveoli and resolved spontaneously and rapidly. Subpleural PIE may be one route the air from ruptured alveoli to the mediastinum.

Chemoembolization for Symptomatic Metastatic Epidural Spinal Cord Compression Refractory to Re-radiotherapy.

PURPOSE: To evaluate the efficacy of chemoembolization for inoperable metastatic epidural spinal cord compression (MESCC) refractory to re-radiotherapy. METHODS: Nineteen consecutive patients with recurrent MESCC after re-radiotherapy who had undergone chemoembolization were retrospectively analyzed. Outcome measures were pain relief rate, neurological improvement rate, objective response rate, and adverse events. MESCC degree classification was assessed using Bilsky grades. Pain assessment was performed using Numerical Rating Scale, and neurological function was evaluated using the Frankel classification. RESULTS: The median follow-up period was 7 (range 2-44) months. All participants had MESCC grade 2 or higher and had severe pain. Fifteen patients (79%) had neurological deficits, and ten had Frankel classification C and five had D. Symptoms were relieved in almost all patients the day following chemoembolization. Pain relief was achieved in 18 of 19 (95%) patients; the median decrease in Numerical Rating Scale score was 8 (range 0-10; p < 0.001). Neurological improvement was achieved in 11 of 15 patients (73%); the median increase in Frankel classification was 1 (range 0-2; p = 0.006). Ten of 19 (53%) patients showed a reduction in MESCC; the median decrease in Bilsky grade was 1 (range 0-2; p = 0.005). There was no correlation between the change in Bilsky grade and pain relief (p = 0.421). However, the decrease in Bilsky grade significantly improved neurological symptoms (p = 0.01). No serious adverse events occurred. CONCLUSION: Chemoembolization may be a useful palliative treatment modality for MESCC refractory to re-radiotherapy. LEVEL OF EVIDENCE: Level 3b, Follow up Study.

Circulation derived from 4D flow MRI correlates with right ventricular dysfunction in patients with tetralogy of Fallot.

We used 4D-flow MRI to investigate circulation, an area integral of vorticity, in the main pulmonary artery (MPA) as a new hemodynamic parameter for assessing patients with a repaired Tetralogy of Fallot (TOF). We evaluated the relationship between circulation, right ventricular (RV) function and the pulmonary regurgitant fraction (PRF). Twenty patients with a repaired TOF underwent cardiac MRI. Flow-sensitive 3D-gradient sequences were used to obtain 4D-flow images. Vortex formation in the MPA was visualized, with short-axis and longitudinal vorticities calculated by software specialized for 4D flow. The RV indexed end-diastolic/end-systolic volumes (RVEDVi/RVESVi) and RV ejection fraction (RVEF) were measured by cine MRI. The PR fraction (PRF) and MPA area were measured by 2D phase-contrast MRI. Spearman ρ values were determined to assess the relationships between circulation, RV function, and PRF. Vortex formation in the MPA occurred in 15 of 20 patients (75%). The longitudinal circulation (11.7 ± 5.1 m2/s) was correlated with the RVEF (ρ = - 0.85, p = 0.0002), RVEDVi (ρ = 0.62, p = 0.03), and RVESVi (ρ = 0.76, p = 0.003) after adjusting for the MPA size. The short-axis circulation (9.4 ± 3.4 m2/s) in the proximal MPA was positively correlated with the MPA area (ρ = 0.61, p = 0.004). The relationships between the PRF and circulation or RV function were not significant. Increased longitudinal circulation in the MPA, as demonstrated by circulation analysis using 4D flow MRI, was related to RV dysfunction in patients with a repaired TOF.

Nodal-based radiomics analysis for identifying cervical lymph node metastasis at levels I and II in patients with oral squamous cell carcinoma using contrast-enhanced computed tomography.

OBJECTIVE: Discriminating metastatic from benign cervical lymph nodes (LNs) in oral squamous cell carcinoma (OSCC) patients using pretreatment computed tomography (CT) has been controversial. This study aimed to investigate whether CT-based texture analysis with machine learning can accurately identify cervical lymph node metastasis in OSCC patients. METHODS: Twenty-three patients (with 201 cervical LNs [150 benign, 51 metastatic] at levels I-V) who underwent preoperative contrast-enhanced CT and subsequent cervical neck dissection were enrolled. Histopathologically proven LNs were randomly divided into the training cohort (70%; n = 141, at levels I-V) and validation cohort (30%; n = 60, at level I/II). Twenty-five texture features and the nodal size of targeted LNs were analyzed on the CT scans. The nodal-based sensitivities, specificities, diagnostic accuracy rates, and the area under the curves (AUCs) of the receiver operating characteristic curves of combined features using a support vector machine (SVM) at levels I/II, I, and II were evaluated and compared with two radiologists and a dentist (readers). RESULTS: In the validation cohort, the AUCs (0.820 at level I/II, 0.820 at level I, and 0.930 at level II, respectively) of the radiomics approach were superior to three readers (0.798-0.816, 0.773-0.798, and 0.825-0.865, respectively). The best models were more specific at levels I/II and I and accurate at each level than each of the readers (p < .05). CONCLUSIONS: Machine learning-based analysis with contrast-enhanced CT can be used to noninvasively differentiate between benign and metastatic cervical LNs in OSCC patients. KEY POINTS: • The best algorithm in the validation cohort can noninvasively differentiate between benign and metastatic cervical LNs at levels I/II, I, and II. • The AUCs of the model at each level were superior to those of multireaders. • Significant differences in the specificities at level I/II and I and diagnostic accuracy rates at each level between the model and multireaders were found.

Unenhanced CT texture analysis with machine learning for differentiating between nasopharyngeal cancer and nasopharyngeal malignant lymphoma.

Differentiating between nasopharyngeal cancer and nasopharyngeal malignant lymphoma (ML) remains challenging on cross-sectional images. The aim of this study is to investigate the usefulness of texture features on unenhanced CT for differentiating between nasopharyngeal cancer and nasopharyngeal ML. Thirty patients with nasopharyngeal tumors, including 17 nasopharyngeal cancers and 13 nasopharyngeal MLs, were underwent 18F-FDG PET/CT. All nasopharyngeal cancers and 7 of 13 nasopharyngeal MLs were confirmed by endoscopic biopsy. On unenhanced CT, 34 texture features were analyzed following lesion segmentation in the maximum area of the target lesion. The Mann-Whitney U test and areas under the curve (AUCs) were used for analysis and to compare the maximum standardized uptake values (SUV)max, SUVmean, and 34 texture features. A support vector machine (SVM) was constructed to evaluate the diagnostic accuracy and AUCs of combinations of texture features, with 50 repetitions of 5-fold cross-validation. Differences between the SUVmax and SUVmean for nasopharyngeal cancers and nasopharyngeal MLs were not significant. Significant differences of texture features were seen, as follows: 1 histogram feature (p = 0.038), 3 gray-level co-occurrence matrix features (p < 0.05), and 1 neighborhood gray-level different matrix feature (NGLDM) (p = 0.003). Coarseness in NGLDM provided the highest diagnostic accuracy and largest AUC of 76.7% and 0.82, respectively. SVM evaluation of the combined texture features obtained the highest accuracy of 81.3%, with an AUC of 0.80. Combined texture features can provide useful information for discriminating between nasopharyngeal cancer and nasopharyngeal ML on unenhanced CT.

Deep Learning for the Preoperative Diagnosis of Metastatic Cervical Lymph Nodes on Contrast-Enhanced Computed ToMography in Patients with Oral Squamous Cell Carcinoma.

We investigated the value of deep learning (DL) in differentiating between benign and metastatic cervical lymph nodes (LNs) using pretreatment contrast-enhanced computed tomography (CT). This retrospective study analyzed 86 metastatic and 234 benign (non-metastatic) cervical LNs at levels I-V in 39 patients with oral squamous cell carcinoma (OSCC) who underwent preoperative CT and neck dissection. LNs were randomly divided into training (70%), validation (10%), and test (20%) sets. For the validation and test sets, cervical LNs at levels I-II were evaluated. Convolutional neural network analysis was performed using Xception architecture. Two radiologists evaluated the possibility of metastasis to cervical LNs using a 4-point scale. The area under the curve of the DL model and the radiologists' assessments were calculated and compared at levels I-II, I, and II. In the test set, the area under the curves at levels I-II (0.898) and II (0.967) were significantly higher than those of each reader (both, p < 0.05). DL analysis of pretreatment contrast-enhanced CT can help classify cervical LNs in patients with OSCC with better diagnostic performance than radiologists' assessments alone. DL may be a valuable diagnostic tool for differentiating between benign and metastatic cervical LNs.

Different indocyanine green fluorescence patterns of two skin metastases of hypopharyngeal squamous carcinoma: A case report.

BACKGROUND: Skin metastasis from primary squamous cell carcinoma of the head and neck is rare . These metastatic lesions are usually detected by physical examination, ultrasound imaging, computed tomography, and positron emission tomography.. Recently, indocyanine green fluorescence angiography (ICG-FA) has been used to discover superficial tumors. However, the optimum timing of ICG injection and fluorescence patterns of skin tumors in ICG-FA are still unknown. CASE PRESENTATION: We encountered a 60-year-old man with hypopharyngeal squamous cell carcinoma. The patient underwent concurrent chemotherapy, radiotherapy, and surgery. However, following these treatments, the patient developed two nodules in the skin of the right upper limb. Thus, the patient underwent ICG-FA. The two skin metastatic nodules showed different fluorescence patterns. One lesion showed high fluorescence intensity during ICG-FA. However, the fluorescence intensity of a small part of the other lesion exceeded that of the surrounding tissue only for a short time. CONCLUSION: We suggest that ICG-FA is effective for detecting skin metastases, and with further studies on the various fluorescence patterns of skin tumors, this technique will become more efficient.

Predictive factors of posttreatment fracture by definitive radiotherapy for uterine cervical cancer.

PURPOSE: Fractures are known to shorten life expectancy and worsen the quality of life. The risk of fractures after radiation therapy in cervical cancer patients is known to be multifactorial. In this study, we examined risk factors for fractures in cervical cancer patients, especially by evaluating bone densities and DVH parameters for fractured bones. MATERIALS AND METHODS: For 42 patients, clinical characteristics, pretreatment CT bone densities, and radiation dose were compared between patients with and without fractures. RESULTS: Posttreatment fractures occurred in 25 bones among ten patients. Pretreatment CT bone densities were significantly lower in patients with fractures (P < 0.05-0.01 across sites, except for the ilium and the ischium). Although DVH parameters were also significantly associated with fractures in univariate analysis, only CT densities were significantly associated with fractures in multivariate analysis. CONCLUSION: Pretreatment CT densities of spinal and pelvic bones, which may reflect osteoporosis, have a significant impact on the risk for posttreatment fractures.

A National Survey on Safety Management at MR Imaging Facilities in Japan.

PURPOSE: To investigate safety management at Japanese facilities performing human MRI studies. METHODS: All Japanese facilities performing human MRI studies were invited to participate in a comprehensive survey that evaluated their MRI safety management. The survey used a questionnaire prepared with the cooperation of the Safety Committee of the Japanese Society for Magnetic Resonance in Medicine. The survey addressed items pertaining to the overall MRI safety management, questions on the occurrence of incidents, and questions specific to facility and MRI scanner or examination. The survey covered the period from October 2017 to September 2018. Automated machine learning was used to identify factors associated with major incidents. RESULTS: Of 5914 facilities, 2015 (34%) responded to the questionnaire. There was a wide variation in the rate of compliance with MRI safety management items among the participating facilities. Among the facilities responding to this questionnaire, 5% reported major incidents and 27% reported minor incidents related to MRI studies. Most major incidents involved the administration of contrast agents. The most influential factor in major incidents was the total number of MRI studies performed at the facility; this number was significantly correlated with the risk of major incidents (P < 0.0001). CONCLUSION: There were large variations in the safety standards applied at Japanese facilities performing clinical MRI studies. The total number of MRI studies performed at a facility affected the number of major incidents.