por John R. Fischer
, Senior Reporter | October 13, 2020
A group of Italian researchers have found remnants of SARS-CoV-2, the virus that causes COVID-19, within the internal components of a CT scanner used to perform a high volume of exams of patients diagnosed with the disease.
The team at the University of Genoa in Genoa, Italy found ribonucleic acid (RNA) from the disease in the inward airflow filter of their CT system. They assert, however, that the discovery is a positive one.
"Our findings clearly show the resilience of SARS-CoV-2 RNA and should prompt caution when the CT gantry is opened for maintenance," Dr. João Matos of the University of Genoa told HCB News. "But at the same time, the results are encouraging since all other internal CT components were free of SARS-CoV-2 RNA. The filter could have been a barrier to virus dissemination. Based on these data, we can hypothesize that the air expelled by the machine was free of SARS-CoV-2 RNA and probably did not end up contaminating the whole CT suite."
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No viral RNA was detected in the dust of the internal case and particularly on the outflow fan system (propeller and grid), the researchers reported, meaning the absence of contamination in both the internal components of the CT gantry and the CT suite room.
The presence of the viral RNA came from a test to see if their 16-slice scanner, a GE Healthcare LightSpeed, could be contaminated. The researchers scanned 180 consecutive patients with the virus over a 26-day period and then opened the gantry to sample the gantry case, inward airflow filter, gantry motor, X-ray tube, outflow fan, fan grid, detectors, and the X-ray tube filter. All samples were analyzed with reverse transcription polymerase chain reaction (RT-PCR) to detect SARS-CoV-2 RNA. They also assessed the samples for the presence of bacterial and fungal agents.
Surface disinfection was performed on the gantry, table, and floor under the table following each procedure with 62–71% ethanol or 0.1% sodium hypochlorite. Passive air exchange was performed for 30–60 minutes, and after each eight-hour shift, the whole CT suite was cleaned with an intermediate-level commercially available disinfectant with bleach. The internal CT components were never cleaned before the sampling procedures.
"We encourage providers to perform sampling of internal components to understand if their CT scan could be a focus of SARS-CoV-2 RNA dissemination," said Matos. "This is especially meaningful in CT scanners imaging a large number of COVID-19 patients in short periods."
Infection control has become a popular topic among clinicians following the outbreak of the virus, with many institutions implementing policies to sanitize equipment before and after each examination. Some, however, are not following correct protocols, as evidenced by a recent letter sent by the Medical Imaging & Technology Alliance (MITA) to the FDA, of reports of inappropriate cleaning agents and disinfectants being used on medical imaging devices
amid the COVID-19 pandemic.
It is important that providers remember that the level of cleaning, the efficacy, methods and process differ, based on the medical device being cleaned
, what its use is, what materials it is made of, and guidelines put out by the CDC and other organizations.
The findings from the study at the University of Genoa were published in European Radiology Experimental