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.

[Endovascular Repair of Infected Thoracic Aortic Aneurysm whose Shape Changed during Treatment of Infection].

We report a successful case of infected thoracic aortic aneurysm treated by endovascular repair. An 82-year-old woman, presenting with intermittent back pain and low-grade fever, was transferred with the diagnosis of infected thoracic aortic aneurysm. High inflammatory reaction and a thickened aortic wall around the aneurysm confirmed the diagnosis. We performed infection control first because enhanced computed tomography (CT) scanning revealed aneurysm was a low-density mass, which denied aortic pseudoaneurysm or rupture. After administration of broad-spectrum antibiotics, low-grade fever was relieved and inflammatory reactions were decreased. CT performed on the 11th hospital day showed the low-density mass was decreased in size. However, CT performed on the 35th hospital day revealed penetrating atherosclerotic ulcer( PAU) into the low-density mass, which was consistent with saccular aortic aneurysm. The patient underwent thoracic endovascular aortic repair( TEVAR). Postoperative course was uneventful and she was discharged on 22nd postoperative day. Oral administration of antibiotics was continued for 6 months after discharge. Eight months after TEVAR, CT revealed disappearance of the aneurysm. The patient showed no recurrence of infection at 5 years of follow-up.