Ultrasound Evaluation for Extremity Deep Vein Thrombus in COVID-19-Positive Patients: Exam Positivity Rate and Association With D-Dimer Level.

OBJECTIVES: Determine the rate of positive extremity ultrasound exams for DVT in patients with COVID-19 and assess for differences in laboratory values in patients with and without DVT, which could be used as a surrogate to decide the need for further evaluation with ultrasound. METHODS: Retrospective case control study with 1:2 matching of cases (COVID-19+ patients) to controls (COVID-19- patients) based on age, gender, and race. Laboratory values assessed were serum D-dimer, fibrinogen, prothrombin time, international normalized ratio, and C-reactive protein. Demographic variables, comorbidities, and clinical variables including final disposition were also evaluated. P-values for categorical variables were calculated with the chi-square test or Fisher's exact test. P-values for continuous variables were compared with the use of a two-tailed unpaired t-test. RESULTS: The rate of extremity ultrasound exams positive for DVT were similar in patients with (14.7%) and without (19.3%) COVID-19 (P = .423). No significant difference was observed in laboratory values including the D-dimer level in COVID-19 patients without (mean 9523.9 ng/mL (range 339 to >60,000)) or with DVT (mean 13,663.7 ng/mL (range 1193->60,000)) (P = .475). No differences were found in demographic variabilities or co-morbidities among COVID-19 patients with and without extremity DVT. CONCLUSIONS: We found no statistically significant difference in rate of positive DVT studies between COVID-19+ and COVID-19- patients. D-dimer levels are elevated, in some cases markedly, in COVID-19 patients with and without DVTs and therefore these data do not support their use as a surrogate when assessing the need for ultrasound evaluation.

Detection of Cortical and Deep Gray Matter Lesions in Multiple Sclerosis Using DIR and FLAIR at 3T.

BACKGROUND AND PURPOSE: The comparative detection rates of deep gray matter (GM) multiple sclerosis (MS) lesions using double inversion recovery (DIR) and fluid-attenuated inversion-recovery (FLAIR) on 3T MR imaging remain unknown. We aimed to assess the detectability of cortical and deep GM MS lesions using DIR and FLAIR on 3T clinical exams and evaluate the relationship between deep GM lesions and brain atrophy. METHODS: One hundred fifty consecutive MS patients underwent routine brain MRI that included 3D DIR and 2D T2 FLAIR on the same 3T scanner. Three neuroradiologists independently reviewed all exams for cortical and deep GM lesions. Statistical parametric mapping (SPM) and FMRIB software library (FSL)-FIRST pipelines were used to determine normalized whole brain and deep GM volumes. RESULTS: A total of 65 cortical and 98 deep lesions were detected on DIR versus 24 and 20, respectively, on FLAIR. Among all 150 patients, the number and percentage of patients with GM lesions on DIR and FLAIR were as follows: cortical 43 (28.7%) versus 24 (16.0%) (P < .001), thalamus 47 (31.3%) versus 20 (13.3%) (P < .001), putamen 10 (6.7%) versus 3 (2.0%) (P = .02), globus pallidus 9 (6.0%) versus 3 (1.3%) (P = .02), and caudate 5 (3.3%) versus 1 (0.7%) (P = .125). Presence of deep GM lesions weakly correlated with deep GM volume fractions. CONCLUSION: Deep GM MS lesions can be detected using routine clinical brain MRI including DIR and FLAIR at 3T. Future studies to optimize these sequences may improve the detection rates of cortical and deep GM lesions. The presence of GM lesions showed weak correlation with GM atrophy.