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.

Partial Anomalous Pulmonary Venous Connection Coexisting with Lung Cancer: A Case Report and Review of Relevant Cases from the Literature.

A 45-year-old man had an abnormal shadow in the right lung field on an annual screening chest X-ray. He was diagnosed with Stage IA (cT1bN0M0) lung cancer. Initially, we did not notice an anomalous vein on non-contrast computed tomography. However, we found that the right upper lobe bronchus branched from the lateral wall of the right main bronchial orifice, above the level of the common right upper lobe bronchus. Therefore, the bronchus was thought to be a tracheal bronchus. We carefully reevaluated the patient using three-dimensional computed tomography angiography. This technique showed that the anomalous right superior pulmonary vein drained into the azygos vein along the superior vena cava. These findings confirmed a partial anomalous pulmonary venous connection of the right upper lobe. We performed video-assisted thoracoscopic right upper lobectomy and mediastinal lymph node dissection for definitive treatment for lung cancer and partial anomalous pulmonary venous connection. No hemodynamic problems occurred in the postoperative course.

Giant pedunclated lipoma of the esophagus: A case report.

INTRODUCTION: Although Esophageal lipoma is extremely rare and pathologically benign, surgical excision of the lipoma is recommended when symptomatic or uncertain biological behavior. In general, some of the esophageal lipoma has a stalk. The pedunclated non-invasive tumor can be removed by stalk ligation, which is either endoscopic or surgical approache. Therefore, the preoperative evaluation is essential. We herein present a case of a huge esophageal lipoma. CASE REPORT: A 82-year-old man, with a wet cough and dyspnea for 6 months, who had the huge mass that almost completely occupied the esophageal lumen, was referred to our institution for the treatment.We diagnosed the mass as non-invasive tumor that has a stalk at the close to the esophageal orifice, by the CT image using air injection into esophageal lumen. We performed excision of the pedunclated huge mobile mass by esophagotomy via right thoracic approach with use of endoloop. Pathological examination showed a lipoma. CONCLUSION: In conclusion, an adequate preoperative evaluation to identify the correct origin of the stalk is mandatory for a successful treatment. In order to do the adequate preoperative evaluation and successful surgery, our diagnostic method of CT image can be effective.

Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner.

PURPOSE: The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. MATERIALS AND METHODS: This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner. RESULTS: The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P < .0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P < .0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary vessels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures. CONCLUSION: Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners.

Kurtosis and skewness assessments of solid lung nodule density histograms: differentiating malignant from benign nodules on CT.

PURPOSE: The purpose of our study was to assess pulmonary nodule characteristics using density histogram kurtosis and skewness and to distinguish malignant from benign nodules. MATERIALS AND METHODS: Ninety-three lung nodules on CT were analyzed, including 72 malignant and 21 benign nodules. They were completely solid or solid with limited ground-glass opacity. Based on their CT characteristics, nodules were categorized into type A, homogeneous nodules with uniform internal structures and clear margins, and type B, inhomogeneous nodules with heterogeneous structures or uneven margins. Kurtosis and skewness were calculated from density histograms to compare type A and B nodules and malignant and benign nodules. Receiver-operating characteristic (ROC) curves were generated to assess kurtosis and skewness for discriminating between different nodule types. RESULTS: Type A nodules (n = 35) had greater kurtosis and reduced skewness (p < 0.001) compared to type B nodules (n = 58). Malignant tumor kurtosis was greater than that of benign nodules (type A, p < 0.05; type B, p = 0.001). Type B malignant tumors had reduced skewness compared to benign nodules (p < 0.05). ROC curves provided relatively high values for the area under the curve (0.71-0.83). CONCLUSION: Kurtosis and skewness assessments of density histograms may be useful for differentiating malignant from benign nodules.

CT findings of a displaced left upper division bronchus in adults: its importance for performing safe left pulmonary surgery.

PURPOSE: The aim of this study was to describe the CT findings of a displaced left upper division bronchus (DLUDB) in adults. MATERIALS AND METHODS: Ten patients with DLUDB were identified. The following CT features were assessed: origin of the DLUDB; distance between the origin of the DLUDB and the origin of the left upper lobe (LUL) bronchus; height of the origin of the DLUDB against the left pulmonary artery (LPA); difference of the main bronchial length; ventilated segment; course of the left pulmonary artery against the DLUDB; and presence of an accessory fissure or other anomalies. RESULTS: DLUDB arose from the posterolateral or lateral aspect of the left main bronchus immediately proximal to the origin of the LUL bronchus. It tended to course along the posterior wall of the LPA and to ventilate the apicoposterior segment with or without the anterior segment. The LPA passed between the displaced bronchus and the lingular bronchus. The origin of the DLUDB was located lower than the inferior wall of the proximal LPA in 6 patients. The accessory fissure between the associated segment and remaining part of the LUL and right tracheal bronchus coexisted in 7 and 3 patients respectively. CONCLUSION: DLUDB has characteristic findings on CT. Radiologists should be aware of this entity and inform the surgeon as it can prevent serious complications in a patient who may undergo lobectomy of the left lung.

Measurement of focal ground-glass opacity diameters on CT images: interobserver agreement in regard to identifying increases in the size of ground-glass opacities.

PURPOSE: To evaluate interobserver agreement in regard to measurements of focal ground-glass opacities (GGO) diameters on computed tomography (CT) images to identify increases in the size of GGOs. MATERIALS AND METHODS: Approval by the institutional review board and informed consent by the patients were obtained. Ten GGOs (mean size, 10.4 mm; range, 6.5-15 mm), one each in 10 patients (mean age, 65.9 years; range, 58-78 years), were used to make the diameter measurements. Eleven radiologists independently measured the diameters of the GGOs on a total of 40 thin-section CT images (the first [n = 10], the second [n = 10], and the third [n = 10] follow-up CT examinations and remeasurement of the first [n = 10] follow-up CT examinations) without comparing time-lapse CT images. Interobserver agreement was assessed by means of Bland-Altman plots. RESULTS: The smallest range of the 95% limits of interobserver agreement between the members of the 55 pairs of the 11 radiologists in regard to maximal diameter was -1.14 to 1.72 mm, and the largest range was -7.7 to 1.7 mm. The mean value of the lower limit of the 95% limits of agreement was -3.1 ± 1.4 mm, and the mean value of their upper limit was 2.5 ± 1.1 mm. CONCLUSION: When measurements are made by any two radiologists, an increase in the length of the maximal diameter of more than 1.72 mm would be necessary in order to be able to state that the maximal diameter of a particular GGO had actually increased.

Bronchial diverticula detected by multidetector-row computed tomography: incidence and clinical features.

PURPOSE: Our aim was to investigate the incidence and characteristics of bronchial diverticula using multidetector-row computed tomography (MDCT) and to evaluate their association with smoking status. MATERIALS AND METHODS: Two radiologists retrospectively reviewed MDCT scans obtained between December 2007 and February 2008 with a 4-row or a 64-row MDCT scanner for 1122 consecutive patients. Bronchial diverticula were assessed for incidence, locations, and sizes. Smoking history, including the Brinkman Index, was recorded from clinical records. Statistical analysis used χ or t tests to evaluate associations between patients' clinical information (age, sex, or smoking history) and the presence of bronchial diverticula. RESULTS: A total of 401 bronchial diverticula were found in 242 (21.6%) patients (mean, 1.65; mode, 1 per patient). Most diverticula were 1 or 2 mm in size. Bronchial diverticula were most frequently detected in the subcarinal region. Of these 242 patients with diverticula, 142 (58.7%) were male and had a higher prevalence than women (P<0.01). No significant difference in age was found between the groups with and without bronchial diverticula. Although bronchial diverticula were also observed in lifelong nonsmokers, the group with bronchial diverticula had a higher percentage of smokers than the group without bronchial diverticula (P=0.01). The Brinkman Index for the group with bronchial diverticula was significantly higher than for the group without diverticula (P<0.01). CONCLUSIONS: Bronchial diverticula are frequently observed on chest MDCT scans and are associated with cigarette smoking.

Subcarinal air cysts: multidetector computed tomographic findings.

OBJECTIVE: The purpose of this study was to assess the computed tomographic (CT) features of subcarinal air cysts, which may be related to bronchial diverticula. METHOD: Seven patients with subcarinal air cysts were retrospectively identified. The following CT features were assessed: location, size, and marginal characteristics of subcarinal air cysts; number, location, and size of communication between the air cyst and bronchi if present; presence of bronchial diverticula in any other location; presence of the pulmonary lesion; and interval change of subcarinal air cysts on follow-up CT. RESULTS: The air cysts were located inferior or inferoposterior to the carina. The subcarinal air cysts typically had a lobulated margin and demonstrated ductlike communications between the air cyst and bronchi. Ductlike communications arose from the posterointerior aspect of the proximal side of main bronchi and were either solitary or multiple. The larger subcarinal air cysts tended to be multiloculated. CONCLUSIONS: Subcarinal air cysts may be considered as part of a spectrum of conditions, which include bronchial diverticula and right paratracheal air cysts. Because of their predictable location and appearance, they should be easily distinguished from pathologic lesions such as pneumomediastinum.

Addison's disease due to tuberculosis that required differentiation from SIADH.

A 77-year-old man was admitted to our hospital complaining of general fatigue. Serum sodium was 116 mEq/l and serum antidiuretic hormone (ADH) was elevated. Radiologic examination revealed nodules in the brain as well as in both adrenal glands. Based on the findings of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), we had considered that the cause of the hyponatremia was syndrome of inappropriate secretion of antidiuretic hormone (SIADH) due to active extrapulmonary tuberculosis. Against our expectations, the patient's condition got worse just after he began antituberculous therapy; we finally diagnosed Addison's disease by additional hormonal tests. His condition recovered immediately with the administration of high-dose hydrocortisone, and the tuberculous lesions became smaller with antituberculous medications. Although tuberculous Addison's disease has been decreasing markedly in recent years, we have to consider the possibility of adrenal insufficiency when hyponatremia is observed in patients with active tuberculosis or those having a past history of tuberculosis.

Simultaneous occurrence of partial anomalous pulmonary venous return and major bronchial anomaly: computed tomography findings in 5 adult patients.

OBJECTIVE: The objective of this study was to describe the computed tomography (CT) findings of 5 adult patients with a combination of partial anomalous pulmonary venous return (PAPVR) and major bronchial anomaly. METHODS: A computerized search of the radiological database records of 4886 consecutive patients who underwent chest CT from April 2005 to May 2007 described 2 patients with a combination of PAPVR and tracheal bronchus (TB). Three additional patients with a combination of PAPVR and TB or accessory cardiac bronchus (ACB) were obtained by reviewing the CT images of the patients initially diagnosed as having PAPVR, TB, or ACB at our institution during the same period. The CT findings of these 5 patients were analyzed. RESULTS: Four patients had a combination of right PAPVR and right TB, and 1 patient had a combination of left PAPVR and ACB. These combinations were found in 42% (5/12) of patients with PAPVR, 16% (4/25) of patients with TB, and 14% (1/7) of patients with ACB. In 4 patients with a combination of right PAPVR and right TB, the anomalous vein was draining the right upper lobe and draining into either the posterior aspect of the superior vena cava (SVC) or the terminal portion of the azygos arch. The origin of the TB was the trachea in 1 patient and the carina in 2 patients. Two distinct TBs presented in 1 patient; the first TB was from the lower trachea, and the second was from the right main bronchus. The right upper lobe affected by PAPVR included the territory ventilated by the TB in all 4 patients. CONCLUSION: A combination of right PAPVR draining to the superior vena cava or azygos arch and right TB is most common. The possibility that the PAPVR and a major bronchial anomaly might coexist in 1 patient should be considered whenever either of them is encountered on CT.

[A case of long-term survival of postoperative brain metastasis of small cell lung cancer effectively treated with chemotherapy, whole brain radiotherapy and stereotactic radiosurgery].

A 63-year-old woman underwent right upper lobectomy for small cell carcinoma. She received a total of 2 courses of carboplatin and etoposide infusion as adjuvant therapy. One year after the operation, because of elevated serum Pro GRP levels and a metastatic brain tumor revealed by CT, 4 courses of IP therapy (irinotecan 60 mg/m(2), day 1, 8, 15 and cisplatin 60 mg/m(2), day 1, every 4 weeks) and whole brain radiotherapy (2 Gy f, 5 f/week, total 40 Gy) were given. A complete response was obtained, but a tumor relapse occurred ten months after the last chemotherapy. We then performed a stereotactic radiosurgery (marginal dose: 22 Gy, maximum dose 44 Gy), and one month later MRI showed the tumor had shrunk markedly. FDG-PET showed no intensive uptake, suggesting that there was no remaining viable tumor. No severe side effects were observed during these treatments. Currently, the patient has been alive with good performance status and no signs of relapse.

[Advance of diagnostic imaging in lung cancer].

The rapid development of CT scanning and the advent of multislice CT have led to its increasing use in the evaluation of lung cancer. The widespread use of CT for the screening of lung cancer has resulted in the detection of many early-stage lung cancers. Recently, (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) systems have become an extremely useful tool in evaluating the primary tumors, regional lymph nodes, and distant metastasis in patients with lung cancer. Moreover, the latest MRI and CAD (Computer-Aided Diagnosis) systems have been introduced in actual clinical practice. This review focuses on the current imaging techniques used to evaluate patients with lung cancer.

Pulmonary dirofilariasis: computed tomography findings and correlation with pathologic features.

OBJECTIVE: The purpose of this study was to describe the computed tomography (CT) and pathologic features of 5 nodules of pulmonary dirofilariasis in 4 patients. METHODS: Four patients with 5 nodules of pathologically confirmed pulmonary dirofilariasis who under went CT were enrolled, and the imaging interpretations were retrospectively compared with the histopathologic characteristics. RESULTS: Three of the 4 patients had a solitary nodule, and the remaining patient had 2 nodules. All the nodules were distributed in the right lower lobe and were attached to the pleura. They were all round or oval in shape and ranged in size from 11 to 22 mm in largest diameter (mean=17 mm). On thinner section CT, the nodules had a well-defined smooth margin with or without a shallow notch; they were connected to the arterial branch and, occasionally, to the venous branch. On contrast-enhanced CT, all the nodules contained a homogeneous low-attenuation area, which corresponded to areas of coagulative necrosis on histopathologic examination. CONCLUSION: Although the CT findings of a pulmonary dirofilariasis nodule are nonspecific, awareness of the findings on contrast-enhanced CT and the pathologic appearance of this rare benign condition may facilitate its differentiation from a malignant nodule.

Risk factor of radiation pneumonitis: assessment with velocity-encoded cine magnetic resonance imaging of pulmonary artery.

OBJECTIVE: The aim of this study was to investigate whether the pulmonary arterial flow obtained as a function of time from velocity-encoded cine (VEC) magnetic resonance (MR) imaging can be used to predict radiation pneumonitis. METHODS: Before receiving radical radiotherapy, 19 patients with primary lung cancer and 21 with primary esophageal cancer underwent VEC MR imaging to determine their pulmonary arterial flow. The right and left pulmonary arterial flow profiles were digitized, and from these data, acceleration time, maximal change in flow rate during ejection, acceleration volume, and the ratio of maximal change in flow rate during ejection to acceleration volume were measured. The statistical significance of differences in pulmonary arterial flows before irradiation between patients who developed and did not develop RP greater than grade 1 was determined. RESULTS: Radiation pneumonitis occurred in 5 patients with lung cancer and in 4 with esophageal cancer. The acceleration time (P < 0.001), acceleration volume (P < 0.02), and ratio of the maximal change in flow rate during ejection to acceleration volume (P < 0.002) in patients with and without RP were significantly different. The sensitivity, specificity, and accuracy of using 111 milliseconds as the cutoff value (which was the mean acceleration time in the RP group) to predict RP were 58%, 88%, and 83%, respectively. CONCLUSIONS: Pulmonary hypertension detected by VEC MR imaging can be a risk factor for development of RP in candidates for pulmonary irradiation.

CT findings of surgically resected large cell neuroendocrine carcinoma of the lung in 38 patients.

OBJECTIVE: We sought to assess the CT features of surgically resected large cell neuroendocrine carcinoma of the lung. MATERIALS AND METHODS: The cases of all patients who underwent surgical resection for primary lung cancer in a single institution from 1993 to 2000 and who received an initial diagnosis of poorly differentiated non-small cell lung carcinoma, small cell carcinoma, carcinoid tumor, and large cell neuroendocrine carcinoma were histologically reviewed. The findings for 43 patients were histologically reclassified and confirmed as large cell neuroendocrine carcinoma. The CT scans available for 38 patients were evaluated by two observers. RESULTS: In the 38 patients, six central tumors and 32 peripheral tumors, with diameters ranging from 12 to 92 mm (mean +/- SD, 32 +/- 19 mm), were identified. None of the tumors had air bronchograms or calcification in the mass or nodule. Of the 19 patients with thin-section CT scans, 14 (74%) showed the tumor-lung interface as well defined and five (26%) showed the interface to be ill defined. Lobulation was identified on 15 scans (79%) and spiculation was evident on six scans (32%). On contrast-enhanced CT scans, inhomogeneously enhanced tumors appeared to be larger (51 +/- 18 mm) than homogeneously enhanced tumors (25 +/- 10 mm; p < 0.001). At histopathologic examination, gross necrosis was noted in 20 of 28 patients who had undergone contrast-enhanced CT, and the cause of inhomogeneous enhancement on CT scans was determined to be intratumoral necrosis. Multiple microscopic necroses were present in all 28 patients. CONCLUSION: Large cell neuroendocrine carcinoma usually appears as a well-defined and lobulated tumor with no air bronchograms or calcification. The inhomogeneous enhancement (caused by necrosis) seen in large cell neuroendocrine carcinomas with large diameters is not necessarily apparent in small-diameter (< 33 mm) large cell neuroendocrine carcinomas, even if the tumor contains necrosis.

Intrapulmonary lymph nodes: thin-section CT features of 19 nodules.

PURPOSE: The purpose of this study was to describe the thin-section CT features of intrapulmonary lymph nodes that accompanied primary or metastatic lung tumors. METHOD: A retrospective analysis of thin-section CT features was performed on 19 nodules in 16 patients with pathologically confirmed intrapulmonary lymph nodes that accompanied primary or metastatic lung tumors. RESULTS: Of the 16 patients, 13 had a solitary nodule and 3 had two nodules. All nodules were distributed in the middle lobe, lingula, or lower lobe. On thin-section CT images, the nodule was located abutting the visceral pleura (n = 10) or within 8 mm of the visceral pleura (n = 9). The thin-section CT findings showed that most of the nodules were well circumscribed (n = 18), homogeneous (n = 19), ovoid (n = 10), or round (n = 9) and smaller than 12 mm in maximal diameter. The surrounding lung field was normal (n = 16). CONCLUSION: Intrapulmonary lymph nodes are subpleural in the lower lung field. On thin-section CT, they are well circumscribed, homogeneous, round or ovoid, and smaller than 12 mm in maximal diameter. In the differential diagnosis of subpleural nodules located in the lower lung field, it should be kept in mind that they may be intrapulmonary lymph nodes even though the patient has malignancy.