Prevalence of phalangeal bone marrow edema on MRI before and during the COVID-19 pandemic and correlation with chilblain skin lesions

Abstract

Objective: The purpose of this study is to establish the prevalence bone marrow edema of the phalanges of the feet and hands before and during the COVID-19 pandemic on MRI studies and correlate with clinically chilblain skin lesions and epidemiological data.

Methods: This observational retrospective study. In patients with confirmed bone marrow edema of the phalanges, epidemiological data and clinical findings were collected, including the history of current or remote COVID-19 infection and vaccination status. The two-proportion test was used to compare the frequency of bone marrow edema in the phalanges before and during the pandemic, and the comparison between the categories variables was performed using the one-proportion test.

Results: Of the total of 7215 patients, only 20 presented isolated bone marrow edema of the digits in MRI studies; 2 (0.05%) were found two years before the pandemic's beginning, and 18 (0.64%) after the pandemic's onset, demonstrating an increase of 13-fold in this period. 16 were women with a mean age of 40.3 years and 4 were men with a mean age of 53.5 years. The most frequently reported clinical symptoms by the patients were pain (85.0%), and erythema of the skin (45.0%). Of the 18 patients found after the pandemic's onset, only 27.8% had COVID-19 infections confirmed by RT-PCR before the imaging study, and all cases were mild.

Conclusion: This study demonstrated a significant increase in the prevalence of bone marrow edema of the phalanges after the onset of the COVID-19 pandemic, particularly in middle-aged and younger women.

Keywords: COVID-19; COVID-toes; Chilblains; MRI.

Fig. 1

21-year-old woman with clinical diagnosis of chilblains at bilateral feet (A and B). FS T2-weighted MRI sequences show bone marrow edema pattern of the phalanges of the feet (arrows—C and E), with low signal intensity on T1-weighted MRI sequences (dotted arrows—D)

Fig. 2

34-year-old woman with pain and swelling in the hands. The baseline MRI study (A and B) shows low signal intensity on a T1-weighted sequence (A) and bone marrow edema pattern on a FS T2-weighted sequence (B). The patient reported improvement of initial clinical symptoms, however, MRI performed after 10 months follow-up (C and D) showed increased bone marrow edema pattern of the phalanges in both T1-weighted (C) and FS T2-weighted (D) sequences

Fig. 3

24-year-old female with ankle pain after a sprain. Incidental finding of bone marrow edema in the hallux distal phalanx in axial, sagittal and coronal FS T2-weighted sequences (arrows – B, C and D). Note normal signal intensity of hallux distal phalanx in T1-weighted sequence (A)

Fig. 4

55-year-old male with hand pain and swelling after COVID-19 infection. FS T2-weighted coronal (B), sagittal (C and D) and axial (E) MRI sequences show bone marrow edema of phalanges (arrows), and normal signal intensity in T1-weighted sequences (A)

Fig. 5

43-year-old female with foot pain, swelling and erythema. Axial T1-weighted (A), FS T2 weighted (B) and FS T1-weighted post-contrast (C) MRI sequences show bone marrow and soft tissue edema of the distal phalanx of the second digit, along with mild post-contrast enhancement of both the bone marrow and peripheral soft tissue (arrows)