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 × 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm × 16 or 0.5 mm × 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 ves sels 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

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

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

Abstract 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

Comparison of Scores for U-HRCT and 16-row C-HRCT Findings.

<p>§: Score was rounded to the first decimal place.</p><p>U-HRCT: ultra-high-resolution CT, C-HRCT: conventional high-resolution CT.</p

CT-pathologic correlation of an adenocarcinoma in situ.

<p>The patient was a 58-year-old female with adenocarcinoma in situ (size, 18 x 16 mm; pT1aN0M0, stage IA). The part-solid nodule was located in segment 6 of the right lower lobe. (A) Loupe view of the pathology specimen (Scale: 1 cm) (H & E, original magnification x1.25). (B) Multiplanar reconstruction (MPR) image from the ultra-high-resolution CT (U-HRCT) data corresponding to the pathology specimen. (C) MPR image from the conventional high-resolution CT (C-HRCT) data corresponding to the pathology specimen. U-HRCT image (Fig B) clearly depicting the solid component (§) immediately adjacent to the bronchial wall (¶) and low-attenuation areas, indicated by a white arrowhead and a white star, in the GGO component of the part-solid nodule. Collapse of the alveolar spaces (§) in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137165#pone.0137165.g005" target="_blank">Fig 5A</a> corresponds to the solid component (§) of the part-solid nodule on the U-HRCT and C-HRCT images (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137165#pone.0137165.g005" target="_blank">Fig 5B and 5C</a>), and the nlarged bronchiole (black arrowhead) and enlarged alveolar air spaces (black stars) in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137165#pone.0137165.g005" target="_blank">Fig 5A</a> correspond to the low-attenuation areas (white arrowhead and white star) in the GGO component of the part-solid nodule on the U-HRCT and C-HRCT images (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137165#pone.0137165.g005" target="_blank">Fig 5B and 5C</a>). The lepidic component indicated by the black dots in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137165#pone.0137165.g005" target="_blank">Fig 5A</a> corresponds to the GGO component (black dot) of the part-solid nodule on the U-HRCT and C-HRCT images (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137165#pone.0137165.g005" target="_blank">Fig 5B and 5C</a>). (D) Maximum intensity projection (MIP) image (2 cm thick) of the pulmonary vessels obtained from the U-HRCT data. (E) MIP image (4 cm thick) of the pulmonary vessels obtained from the C-HRCT data. Fine pulmonary vessels are depicted on the MIP image reconstructed from the U-HRCT data (black arrows). The size of the fine pulmonary vessels, as indicated by the black arrows (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137165#pone.0137165.g005" target="_blank">Fig 5D</a>), was 0.2 mm. The black star in each MIP image indicates the part-solid nodule of the adenocarcinoma in situ. (F) 3D curved-MPR image of the pulmonary bronchi from the U-HRCT data. (G) 3D curved-MPR image of the pulmonary bronchi from the C-HRCT data. U-HRCT image (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137165#pone.0137165.g005" target="_blank">Fig 5F</a>) clearly depicting the part-solid opacity (black arrowhead) immediately adjacent to the bronchial wall (white star) with traction bronchiectasis caused by the collapse of the alveoli in the tumor. A: pulmonary artery. V: pulmonary vein.</p

Example of CT images for the observer test.

<p>(A) An example of an ultra-high-resolution CT image with different colored dots and annotations used for the observer test. The X and Y coordinates of each dot are shown in parentheses. The image shows a lepidic-predominant invasive adenocarcinoma with a tumor size of 1.2 x 0.9 x 0.9 cm located in segment 2 of the right upper lobe in a 73-year-old man. The blue dot indicates the edge of a solid nodule. The green dot indicates a cavity. The yellow dot indicates pleural indentation of the interlobar fissure. The white dot indicates a fissure between the right upper lobe and the right lower lobe. The red dot indicates the margin of the pulmonary vessel. The purple dot indicates the edge of a bronchiole. The gray dot indicates an interlobular septum. (B) Ultra-high-resolution CT image in which the dots and annotations are hidden.</p

Appearance and geometry of channel direction of the prototype ultra-high-resolution CT scanner.

<p>(A) External appearance of the prototype ultra-high-resolution CT scanner. The bore size was 72 cm in diameter. (B) Image showing the directions of the slices and the channels of the CT detector. (C) Geometry of channel direction of the prototype ultra-high-resolution CT scanner. The maximal field of view was 250 mm and number of the channels was 896. (D) Geometry of channel direction of the conventional high-resolution CT scanner. The maximal field of view was 500 mm and number of the channels was 896. U-HRCT: ultra-high-resolution CT, C-HRCT: conventional high-resolution CT.</p