Chest CT Diagnosis of COVID-19: Accuracy using CO-RADS and CT-Involvement Scoring.

OBJECTIVES: Both Reporting and Data System (CO-RADS) and CT-involvement scores (CTIS) have been proposed for evaluation of COVID-19 on chest CT. The purpose of this single-center, retrospective study was to evaluate both scoring systems to diagnose COVID-19 infection in a high-prevalence area. MATERIALS AND METHODS: Chest CT datasets (n = 200) and available reverse transcription polymerase chain reaction (RT-PCR) on nasopharyngeal swab were included. CT scans were assigned to four 'imaging groups' after scoring for both CO-RADS and CTIS. Diagnostic accuracy of chest CT was calculated respectively using RT-PCR and clinical diagnosis as gold standards: False-negatives and false-positives of chest CT regarding RT-PCR were studied in more depth using the medical files. RESULTS: The 'imaging group' including CO-RADS 4/5 scores reached the highest diagnostic values for COVID-19 considering either the initial RT-PCR or the final clinical diagnosis as the standard of reference: accuracies of 172/200 (86%) to 181/200 (90.5%), sensitivities of 60/80 (88.2%) to 70/79 (88.6%), specificities of 112/132 (84.9%) to 111/121 (91.7%), negative predictive values (NPV) of 112/120 (93.3%) to 111/120 (92.5%), respectively. False-negative CTs regarding RT-PCR were mainly explained by imaging very early in the disease course (5 out of 8 cases) or COVID-19 infection with no/minor respiratory symptoms (3 out of 8 cases). CONCLUSION: Assessing chest CT using CO-RADS is a valuable diagnostic approach for COVID-19 infection in a high-prevalence area, with a higher accuracy than CTIS.

National audit on the appropriateness of CT and MRI examinations in Luxembourg.

OBJECTIVES: In Luxembourg, the frequency of CT and MRI examinations per inhabitant is among the highest in Europe. A national audit was conducted to evaluate the appropriateness of CT and MRI examinations according to the national referral guidelines for medical imaging. METHODS: Three hundred and eighty-eight CT and 330 MRI requests corresponding to already performed examinations were provided by all radiology departments in Luxembourg. Four external radiologists evaluated the clinical elements for justification present in each request. They consensually assessed the appropriateness of each requested examination with regard to the national referral guidelines and their clinical experience. RESULTS: The appropriateness rate (AR) was higher for MRI requests than for CT requests (79% vs. 61%; p < 0.001). AR was higher for requests referred by medical specialists rather than by general practitioners, both for CT requests (70% vs. 37%; p < 0.001) and MRI requests (83% vs. 64%; p = 0.002). For CT, AR was higher when the requests concerned paediatric rather than adult patients (82% vs. 58%; p < 0.001), when the radiology departments were equipped with both CT and MRI units rather than with only CT units (65% vs. 47%, p = 0.004) and when the requests concerned head-neck (79%), chest (77%) and chest-abdominal-pelvic (81%) areas rather than spinal (28%), extremity (51%) and abdominal-pelvic (63%) areas (p < 0.001). CONCLUSIONS: The appropriateness of CT and MRI in Luxembourg is not satisfactory and collective efforts to improve should be continued. The focus should be on general practitioners and on spinal CT examinations.

Junctional zone thickness in young nulliparous women according to menstrual cycle and hormonal contraception use.

This prospective study aims to determine the optimal menstrual phase and uterine location to detect the thickest junctional zone by magnetic resonance imaging (MRI). Healthy nulliparous women were subdivided according to their use of hormonal contraception. Each women was investigated three times during their menstrual cycle. Eighteen nulliparous non-users and 29 nulliparous users of hormonal contraception (mean age 26.4 and 25.8 years, respectively) underwent a pelvic MRI (1.5T) examination during the follicular, ovulatory and luteal phase. The junctional zone thickness was measured at six locations in the uterine wall. A significantly thinner junctional zone was observed at the anterior and posterior wall of the midcorpus (P = 0.01 and P = 0.004 respectively) and fundus (P = 0.009 and P = 0.023 respectively), in the contraception users compared with the non-users. No differences in junctional zone thickness were noticed between the menstrual phases and the uterine wall locations. The ratio of junctional zone versus total myometrial thickness was also different between both groups and between the assessed uterine locations. To conclude, any phase in the menstrual cycle and location within the uterine wall was validated to determine the junctional zone thickness on MRI, although the fundal location is preferred.