Cardiac MRI Findings of Myocarditis After COVID-19 mRNA 
Vaccination in Adolescents
Lydia Chelala, MD1, Jean Jeudy, MD2, Rydhwana Hossain, MD2, Geoffrey Rosenthal, MD2, Nicholas Pietris, MD2,  
Charles S. White, MD2

C a r d i o t h o r a c i c   I m a g i n g   ·   O r i g i n a l   R e s e a r c h

Keywords

COVID-19, MRI, myocarditis, vaccination

Submitted: Sep 15, 2021
Revision requested: Sep 24, 2021
Revision received: Oct 8, 2021
Accepted: Oct 17, 2021
First published online: Oct 27, 2021

The authors declare that they have no 
disclosures relevant to the subject matter of 
this article.

BACKGROUND. A possible association has been reported between COVID-19 mes-

senger RNA (mRNA) vaccination and myocarditis.

OBJECTIVE. The purpose of our study was to describe cardiac MRI findings in pa-

tients with myocarditis after COVID-19 mRNA vaccination.

METHODS. This retrospective study included patients without known prior SARS-
CoV-2 infection who underwent cardiac MRI between May 14, 2021, and June 14, 2021, 
for suspected myocarditis within 2 weeks of COVID-19 mRNA vaccination. Information 
regarding  clinical  presentation,  hospital  course,  and  events  after  hospital  discharge 
were recorded. A cardiothoracic imaging fellow and cardiothoracic radiologist reviewed 
cardiac MRI examinations in consensus. Data were summarized descriptively.

RESULTS. Of 52 patients without known prior SARS-CoV-2 infection who underwent 
cardiac MRI during the study period, five underwent MRI for suspected myocarditis after 
recent COVID-19 mRNA vaccination. All five patients were male patients ranging in age 
from 16 to 19 years (mean, 17.2 ± 1.0 [SD] years) who presented within 4 days of receiving 
the second dose of a COVID-19 mRNA vaccine. Troponin levels were elevated in all pa-
tients (mean peak troponin I value, 6.82 ± 4.13 ng/mL). Alternate possible causes of myo-
carditis were deemed clinically unlikely on the basis of medical history, physical exam-
ination findings, myocarditis viral panel, and toxicology screening. Cardiac MRI findings 
were consistent with myocarditis in all five patients on the basis of the Lake Louise crite-
ria, including early gadolinium enhancement and late gadolinium enhancement (LGE) in 
all patients and corresponding myocardial edema in four patients. All five patients had 
a favorable hospital course and were discharged from the hospital in stable condition 
with improved or resolved symptoms after hospitalization (mean length of hospital stay, 
4.8 days). Two patients underwent repeat cardiac MRI that showed persistent, although 
decreased, LGE. Three patients reported mild intermittent self-resolving chest pain after 
hospital discharge, and two patients had no recurrent symptoms after discharge.

CONCLUSION. In this small case series, all patients with myocarditis after COVID-19 
vaccination were male adolescents and had a favorable initial clinical course. All patients 
showed cardiac MRI findings typical of myocarditis from other causes. LGE persisted in 
two patients who underwent repeat MRI. These observations do not establish causality.
CLINICAL  IMPACT.  Radiologists  should  be  aware  of  a  possible  association  of 
COVID-19 mRNA vaccination and myocarditis and recognize the role of cardiac MRI in 
the assessment of suspected myocarditis after COVID-19 vaccination.

COVID-19 has been associated with more than 170 million confirmed cases and more 
than 3.7 million deaths worldwide since its initial recognition [1]. As national and global 
responses have sought to contain the spread of COVID-19, significant resources have been 
applied to the development of a safe and effective vaccine [2, 3]. Within 1 year of release of 
the SARS-CoV-2 genome, two messenger RNA (mRNA) vaccines were approved for emer-
gency use in several countries [4]. Advancements in vaccine development over the past 
decades—most  notably,  the  advent  of  mRNA  vaccination—fostered  this  achievement. 
Compared with conventional vaccines (i.e., vaccines involving live attenuated and inac-
tivated pathogens), the new mRNA vaccines facilitate rapid development and large-scale 
deployment, serving as an attractive alternative in the setting of a global emergency [5]. 

1Department of Diagnostic Radiology, University of Chicago Medicine, 5841 S Maryland  Ave, Chicago, IL 60637. 
Address correspondence to L. Chelala (LChelala@radiology.bsd.uchicago.edu).

2Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Medical Center, 22 S Greene St, 
Baltimore, MD 21201.

www.ajronline.org | 651

Chelala et al.
MRI of Patients With Myocarditis After COVID-19 Vaccination

Chelala L, Jeudy J, Hossain R, Rosenthal G, Pietris N, White 
CS
Cardiothoracic Imaging

Original Research

doi.org/10.2214/AJR.21.26853

AJR 2022; 218:651–658

ISSN-L 0361–803X/22/2184–651 

© American Roentgen Ray Society

AJR:218, April 2022 

 
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C h e l a l a   e t   a l .

More than 6 billion doses of mRNA vaccine had been admin-
istered globally as of October 10, 2021 [1], and health authorities 
have closely monitored vaccine safety. As vaccination rates con-
tinue to rise, rare side effects have been reported. For example, 
concern for a possible association between COVID-19 mRNA vac-
cination and myocarditis in young individuals was first raised by 
researchers in Israel [6–9]. Subsequently, in the United States oc-
currences of myopericarditis in adolescents and young adults af-
ter COVID-19 mRNA vaccination have also been reported by the 
Vaccine Adverse Event Reporting System (VAERS) [6–8, 10]. This 
possible  association  warrants  further  investigation,  particularly 
given the expansion on May 10, 2021, of the emergency approval 
of the BNT162b2 mRNA COVID-19 vaccine (Pfizer-BioNTech; here-
after referred to as the Pfizer-BioNTech vaccine) by the U.S. FDA 
to include adolescents 12–15 years old. Thus, the aim of this study 
was to describe cardiac MRI findings in patients with myocarditis 
after COVID-19 mRNA vaccination.

Methods
Patients

The institutional board review granted an exemption after re-
view  of  this  single-institution  HIPAA-compliant  retrospective 
study.  The  requirement  for  informed  consent  was  waived.  The 
records  of  all  patients  who  underwent  cardiac  MRI  at  our  insti-
tution between May 14, 2021, and June 14, 2021, were reviewed 
to identify those who underwent the examination because of a 
clinical suspicion for myocarditis. Patients were then excluded if 
they had a known history of SARS-CoV-2 infection or if they had 
not undergone COVID-19 vaccination within 2 weeks before MRI. 
The  remaining  patients  formed  the  study  sample,  representing 
patients who underwent cardiac MRI for suspected myocarditis 
in the setting of recent COVID-19 vaccination. 

A  cardiothoracic  imaging  fellow  (L.C.)  reviewed  the  electronic 
medical records (EMRs) to identify included patients’ demograph-
ic characteristics, medical history, results of biochemical laborato-
ry testing, ECG results, and findings from echocardiography, which 
were recorded in a secure database (Table 1). This investigator also 
recorded  information  regarding  patients’  hospital  course,  condi-
tion at hospital discharge, and clinical events (including recurrent 
symptoms and follow-up cardiac imaging) after discharge.

Cardiac MRI Acquisition and Interpretation

All cardiac MRI examinations were performed using a 1.5-T mag-
net (Magnetom Sola, Siemens Healthcare). The protocol included 
the  following  sequences:  axial  and  multiplanar  cine  precontrast 
SSFP,  T1-  and  T2-weighted  spectral  adiabatic  inversion  recovery 
(SPAIR), perfusion imaging, early postcontrast short-axis SSFP, time 
inversion  scout,  and  multiplanar  T1-weighted  inversion  recovery 
segmented  breath-hold  late  gadolinium  enhancement  (LGE)  im-
aging. The LGE imaging was performed using IV administration of 
gadobenate dimeglumine. T1 and T2 parametric imaging was ac-
quired at the discretion of the protocoling radiologist. For the scan-
ner that performs cardiac MRI at our institution (University of Mary-
land Medical Center), normal reference native T1 parametric values 
were determined to be less than 1100 milliseconds, and normal T2 
parametric values were determined to be less than 55 milliseconds.
The  images  from  the  cardiac  MRI  examinations  were  retro-
spectively reviewed in consensus by the previously noted cardio-

HIGHLIGHTS

Key Finding
	„ This retrospective case series identified five patients who 
underwent cardiac MRI for suspected myocarditis after 
COVID-19 mRNA vaccination. All patients were male 
adolescents and had a favorable initial clinical course. All 
patients showed cardiac MRI findings typical of 
myocarditis of other causes. LGE persisted in two patients 
who underwent repeat MRI.

Importance
	„ Radiologists should recognize the possible association of 
COVID-19 mRNA vaccination and myocarditis and the 
role of cardiac MRI in this clinical context.

thoracic imaging fellow (L.C.) and by a cardiothoracic radiologist 
with  5  years  of  experience  (R.H.);  independent  interpretations 
were not performed given the very small sample size. The read-
ers  initially  compared  cardiac  functional  assessment  between 
MRI  and  echocardiography.  The  readers  then  assessed  for  in-
dividual  findings  associated  with  the  diagnosis  of  myocarditis 
based on the updated 2018 Lake Louise criteria (LLC), which in-
corporate a combination of T1- and T2-based criteria [11]. The T1-
based criteria encompassed the presence of early gadolinium en-
hancement  (EGE),  presence  of  LGE,  and  increased  T1  relaxation 
times. The T2-based criteria encompassed the presence of focal 
myocardial  edema,  increased  myocardial  T2  signal  intensity  ra-
tios, and increased T2 relaxation times. 

The readers also recorded the presence of a pericardial effusion 
and  of  pericardial  enhancement.  A  pericardial  effusion  with  the 
pericardial  fluid  width  measuring  less  than  4  mm  was  character-
ized as trace, and a pericardial effusion with the pericardial fluid 
width measuring 4–5 mm was characterized as small [12]. In addi-
tion, the readers evaluated the lung parenchyma and pleura for ab-
normalities on the axial SSFP sequence. Finally, the readers deter-
mined if the cardiac MRI examination was overall consistent with 
a diagnosis of myocarditis in consideration of the LLC. In patients 
who underwent a follow-up cardiac MRI examination after hospi-
tal discharge, the two investigators reviewed the follow-up MRI in 
a similar fashion. Imaging findings were summarized descriptively.

Results
Patient Demographics and Clinical Presentation

During the study period, 52 patients underwent cardiac MRI. Of 
these patients, 41 were excluded because of the following indica-
tions for MRI other than myocarditis: familial cardiomyopathy (n = 
1), personal history of congenital heart disease (n = 5), cardiomy-
opathy (n = 31), and valvular disease (n = 4). The remaining 11 pa-
tients were referred for cardiac MRI because of a clinical suspicion 
for myocarditis based on the presence of chest pain or discomfort, 
elevated troponin values, and possible ECG abnormality. Of these 
11  patients  with  suspected  myocarditis,  four  were  excluded  be-
cause  of  a  known  history  of  SARS-CoV-2  infection  and  two  were 
excluded because they had not received a COVID-19 vaccine with-
in the 2 weeks before MRI. The remaining five patients formed the 
study sample.

652 

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mRNA COVID-19 vaccine manufacturer

Pfizer-BioNTecha

Pfizer-BioNTecha

Pfizer-BioNTecha

Modernab

Pfizer-BioNTecha

M R I   o f   P a t i e n t s   W i t h   M y o c a r d i t i s   A f t e r   C O V I D -19   V a c c i n a t i o n

The demographic characteristics, clinical information, and im-
aging findings for the five included patients are summarized in 
Table 1. All five patients were male. Patient age ranged from 16 
to 19 years (mean age, 17.2 ± [SD] 1.0 years). All patients were re-
ferred  to  our  institution  after  presenting  to  an  outside  hospital 
with acute chest pain. All patients reported the onset of symp-
toms within 4 days of receiving the second dose of a COVID-19 
mRNA  vaccine.  Four  patients  received  the  Pfizer-BioNTech  vac-
cine, and one patient received the mRNA-1273 COVID-19 vaccine 
(Moderna; hereafter referred to as the Moderna vaccine). No pa-
tient had known contact with a patient positive for SARS-CoV-2 

infection. The SARS-CoV-2 nasal polymerase chain reaction (PCR) 
test was negative in all five patients. No patient reported signifi-
cant cardiovascular risk factors or a history of previous cardiovas-
cular events. Medications included ergocalciferol in one patient 
and buspirone and desvenlafaxine in one patient.

Initial Clinical Workup

ECG performed at presentation was normal in three patients. 
Diffuse ST segment elevation was present in one patient, and si-
nus bradycardia was present in one patient. Troponin levels were 
elevated  at  initial  presentation  in  all  patients.  Mean  initial  and 

TABLE 1:  Patient Demographics, Clinical Presentation, Biochemical Laboratory Findings, and 

Characteristic

Patient A

Patient B

Patient C

Patient D

Patient E

Imaging Findings

Demographics

Age (y)

Sex

Clinical presentation and laboratory results

No. of vaccine doses received

Interval between vaccine dose and clinical 

symptoms (d)

ECG findings

Peak troponin I value (ng/mL)

CRP value (mg/dL)

Myocarditis panel

Toxicology screening

Hospitalization length of stay (d)

Echocardiography findings

Interval between vaccination and MRI (d)

Biventricular size

Biventricular function

Additional findings

Cardiac MRI findings

LVEF (%)

RVEF (%)

LVEDV/BSA (mL/m2)

RVEDV/BSA (mL/m2)

Early gadolinium enhancement

Late gadolinium enhancement

Myocardial edema

Pericardial effusion

16

Male

2

4

9

1.38

0.16

8

57

53

85

86

Yes

Yes

Yes

Small

17

Male

2

4

4

4.81

1.70

Negative

Negative

5

56

54

86

86

Yes

Yes

Yes

Trace

Normal

Normal

Diffuse ST elevation

Normal

Sinus bradycardia

Negative

Not performed

IgG EBV antibodies

Negative

Negative

Not performed

Normal

Normal

Normal

Normal

Normal

Normal

Normal

LVEF, 40–45%; global 
LV hypokinesis

Normal

Normal

None

Ectasia of RCA and LAD Hyperechoic septum

None

None

17

Male

2

3

3

4.91

18.00

5

60

58

71

69

Yes

Yes

No

Trace

19

Male

2

3

3

10.00

4.12

Negative

Marijuana

6

46

50

91

74

Yes

Yes

Yes

Trace

17

Male

2

4

3

1.38

1.40

5

62

55

62

79

Yes

Yes

Yes

Small

Distribution of enhancementc

4, 6, and 12

4, 5, 10, and 11

5, 6, and 12

5, 6, 11, 12, and 16

5, 6, 11, 12, and 13

Note—mRNA = messenger RNA, CRP = C-reactive protein, EBV = Epstein-Barr virus, LVEF = left ventricular ejection fraction, LV = left ventricle, RCA = right coronary 
artery, LAD = left anterior descending artery, RVEF = right ventricular ejection fraction, LVEDV = left ventricular end-diastolic volume, BSA = body surface area, RVEDV = 
right ventricular end-diastolic volume.
aManufacturer of the BNT162b2 mRNA COVID-19 vaccine.
bManufacturer of the mRNA-1273 COVID-19 vaccine.
cReported using the 17-segment American Heart Association model.

AJR:218, April 2022 

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C h e l a l a   e t   a l .

A

D

G

J

B

E

H

C

F

I

Fig. 1—T1-based criteria for myocarditis on cardiac MRI in patients who recently received COVID-19 
messenger RNA vaccination. 
A–E, Compared with precontrast SSFP sequence (not shown), early gadolinium enhancement (EGE) (arrow) is 
observed on early postcontrast short-axis SSFP images in 16-year-old boy (A), 17-year-old boy (B), 17-year-old 
boy (C), and 19-year-old man (D) and on early postcontrast short-axis perfusion image in 17-year-old boy (E). 
Patients in A–E correspond with patients A–E in Table 1, respectively.
F–J, Late gadolinium enhancement (LGE) (arrows) is also present in all five patients: F, G, H, I, and J show 
same patients as shown in A, B, C, D, and E, respectively. EGE and LGE predominantly affect subepicardium 
of inferior, inferolateral, or anterolateral walls. EGE extends beyond confines of LGE in patient shown in A and 
F and patient shown in B and G. Basilar left ventricle (LV) involvement is present in patient shown in A and 
F, patient shown in B and G, and patient shown in C and H. Midcavity LV involvement is present in patient 
shown in D and I and patient shown in E and J. 

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M R I   o f   P a t i e n t s   W i t h   M y o c a r d i t i s   A f t e r   C O V I D -19   V a c c i n a t i o n

peak troponin I (TnI) levels measured 5.88 ± 4.26 ng/mL (n = 4 pa-
tients) and 6.82 ± 4.13 ng/mL (n = 5), respectively (normal, < 0.04 
ng/mL). Mean initial and peak troponin T (TnT) levels measured 
0.33 ± 0.13 ng/mL (n = 2 patients) and 0.65 ± 0.02 ng/mL (n = 2), 
respectively (normal, < 0.14 ng/mL). The B-type natriuretic pep-
tide (BNP) value was normal in the four patients who underwent 
BNP testing (mean BNP value in these four patients, 206.5 ± 206.7 
pg/mL). The C-reactive protein level was elevated in four patients 
(mean value in these four patients, 5.1 ± 6.6 mg/dL) and was nor-
mal in one patient. 

A myocarditis viral panel excluded an acute viral infection in 
four patients. One patient had prior Epstein-Barr virus infection, 
as shown by positive IgG titers. Toxicology screening in three pa-
tients  was  negative  aside  from  marijuana  positivity  in  one  pa-
tient, which was deemed unlikely to be the cause of that patient’s 
presentation. Other potential major causes of myocarditis, aside 
from  the  recent  vaccination,  were  deemed  clinically  unlikely  in 
all patients on the basis of the absence of a significant medical 
history, a lack of contributory findings on physical examination, 
negative PCR result for SARS-CoV-2, and negative myocarditis vi-
ral panel. No patient underwent endomyocardial biopsy.

Echocardiography

All five patients underwent echocardiography because of clinical-
ly suspected myocarditis. Echocardiography was performed a mean 

of 5.0 ± 0.9 days after the second vaccine dose (range, 4–6 days). On 
echocardiography,  the  left  ventricular  ejection  fraction  (LVEF)  was 
mildly to moderately decreased and associated with global hypoki-
nesis in one patient and was normal in the remaining four patients. 
Biventricular size and right ventricular ejection fraction (RVEF) were 
normal in all patients. No patient exhibited segmental wall motion 
abnormalities. Ectasia of the right coronary artery and left anterior 
descending artery was identified in one patient.

Cardiac MRI

Cardiac MRI was performed a mean of 5.8 ± 1.2 days after the 
second  vaccine  dose  (range,  5–8  days),  within  0.5  ±  1.5  days  of 
the  TnI  peak  (range,  from  2  days  before  to  2  days  after  the  TnI 
peak), and 1.3 ± 0.5 days after the TnT peak (range, 1–2 days after 
the TnT peak). Functional assessment on cardiac MRI was concor-
dant  with  echocardiography  in  all  patients.  Specifically,  cardiac 
MRI showed a mildly decreased LVEF of 46% and global hypoki-
nesis in one patient and a normal functional assessment in four 
patients. Cardiac MRI showed no segmental wall motion abnor-
malities in any patient. 

Cardiac MRI showed both EGE and LGE in all five patients. The 
LGE  images  showed  purely  subepicardial  enhancement  in  four 
patients  and  mid-to-subepicardial  enhancement  in  one  patient 
(Fig. 1). All patients showed involvement of the inferior, inferolat-
eral, or anterolateral walls. All patients showed basilar and mid-

A

D

C

Fig. 2—Qualitative and quantitative T2-based 
criteria for myocarditis on cardiac MRI in patients 
who recently received COVID-19 messenger RNA 
vaccination. 
A and B, Qualitative criterion was focal myocardial 
edema (arrow) and is shown on four-chamber 
precontrast SSFP images in 16-year-old boy (A) and 
17-year-old boy (B). 
C, Quantitative criteria included T2 parametric 
mapping and quantification of myocardial signal 
intensity ratios. Focal subepicardial edema of basilar 
left ventricular inferior wall (arrow) is shown on 
source image from T2 mapping in 17-year-old boy.
D, Increased myocardial signal intensity ratio of 
3.0 at mid cavity is shown in 19-year-old man. AR = 
surface area, AV = average.
E, Qualitative focal myocardial edema (arrow) is 
also shown on short-axis precontrast SSFP image 
in 17-year-old boy. Patients in A–E correspond with 
patients A–E in Table 1, respectively.

B

E

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C h e l a l a   e t   a l .

cavity  involvement;  two  patients  showed  apical  involvement. 
T1 and T2 parametric imaging was performed in three patients. 
Two of these patients showed elevated segmental T1 relaxation 
times; one of these two patients showed segmental T2 relaxation 
times that were near the upper limit of normal, and one exhibit-
ed elevated segmental T2 relaxation times. Segmental T1 and T2 
relaxation times were normal in the remaining patient. In four pa-
tients, qualitative assessment of T2-weighted sequences showed 
focal myocardial hyperintensity suggestive of edema that corre-
sponded with areas of EGE and LGE on postcontrast imaging (Fig. 
2). The myocardial T2 signal intensity ratio was increased (> 1.8) 
in all five patients. Three patients exhibited a trace pericardial ef-
fusion, and two patients exhibited a small pericardial effusion. No 
patient showed pericardial enhancement or lung parenchymal or 
pleural abnormalities on cardiac MRI. Based on the LLC, the cardi-
ac MRI examinations were consistent with a diagnosis of myocar-
ditis in all five patients.

Hospital Course, Condition at Hospital 
Discharge, and Clinical Events After Discharge

Of the five patients, one experienced nonsustained ventricular 
tachycardia on day 2 of hospitalization. No other patient experi-
enced a major clinical event during or after hospital admission. 
All  five  patients  showed  persistent  decreases  in  troponin  levels 
and  improvement  or  resolution  of  chest  pain,  and  all  were  dis-
charged from the hospital in stable condition. The mean hospi-
talization length of stay was 4.8 days (range, 3–9 days). One pa-
tient  was  discharged  without  any  medications  prescribed.  The 
patient with left ventricular systolic dysfunction on imaging was 
prescribed at hospital discharge colchicine and metoprolol. One 
patient was prescribed at discharge an NSAID for pain control. An 
additional patient was prescribed at discharge 81 mg of aspirin 
daily. The remaining patient was prescribed at discharge 25 mg 
of metoprolol extended release daily.

The  mean  length  of  clinical  follow-up  after  hospital  discharge 
based on availability of records at the time of last EMR review was 95 
days (range, 92–104 days). During the follow-up period, two patients 
underwent repeat cardiac MRI. In both patients, the repeat cardiac 
MRI  showed  stable  biventricular  size  and  function;  persistent,  but 
decreased, LGE that was similar in distribution to the initial MRI; and 
an absence of new areas of abnormality. In the patient with right cor-
onary artery ectasia on echocardiography, this finding was shown to 
have resolved on follow-up echocardiography. 

Three patients reported mild intermittent self-resolving chest 
pain after hospital discharge. In the first of the three patients, the 
recurrent symptoms occurred after discontinuation of the NSAID 
that had been prescribed at discharge. In the second patient, the 
recurrent symptoms resulted in an emergency department visit. 
In the third patient, symptoms consisted of mild, self-resolved in-
termittent chest pain. The two remaining patients had no recur-
rent symptoms after discharge. One of these two asymptomatic 
patients had persistent LGE on follow-up cardiac MRI.

Discussion

A possible causal association between COVID-19 mRNA vacci-
nation and myocarditis has been reported [6, 9]. In this series of 
five patients, we describe the cardiac MRI findings of myocardi-
tis in the setting of recent COVID-19 mRNA vaccination. The ob-

served findings are typical of other forms of myocarditis, such as 
viral or idiopathic myocarditis. All patients showed EGE and LGE 
on cardiac MRI. The LGE was predominantly subepicardial and in-
volved  the  inferior,  inferolateral,  or  anterolateral  walls  in  all  pa-
tients.  Focal  myocardial  edema  in  the  areas  of  enhancement 
was  observed  in  four  patients.  All  patients  also  showed  basilar 
involvement.  Two  of  three  patients  who  underwent  parametric 
mapping  showed  concordant  elevated  T1  relaxation  times  and 
either elevated T2 relaxation times or T2 relaxation times at the 
top end of the normal range, supporting the diagnosis.

Myocarditis after COVID-19 vaccination is uncommon [9]. How-
ever,  its  prevalence  may  be  underestimated  because  of  the  re-
liance  on  symptoms  for  suspecting  the  diagnosis.  A  study  in 
young  athletes  with  confirmed  SARS-CoV-2  infection  showed 
that a substantial proportion of individuals had subclinical myo-
carditis  on  screening  cardiac  MRI  [13].  Subclinical  myocarditis 
may also be possible after COVID-19 vaccination. Indeed, one pa-
tient in the present sample had persistent LGE on follow-up MRI 
when asymptomatic. To better understand a possible association 
between  COVID-19  vaccination  and  myocarditis,  the  CDC  has 
encouraged further investigation of myocarditis after COVID-19 
mRNA vaccination [14].

In  prior  reports,  patients  with  possible  myocarditis  after 
COVID-19 mRNA vaccination have been predominantly male and 
16–24 years old, have most commonly presented within 1 week 
of  the  second  vaccine  dose,  and  have  had  mild  disease  course 
[9, 10]. However, the findings on cardiac MRI have not been well 
reported. To our knowledge, this report is the first to further de-
scribe  the  results  of  short-term  follow-up  in  these  patients,  in-
cluding findings on repeat cardiac MRI. 

Consistent  with  prior  reports,  the  patients  in  our  series  were 
young male patients who presented within days after receiving 
the second dose of COVID-19 mRNA vaccine. Patients had a favor-
able hospital course and were discharged in stable condition. On 
short-term follow-up after hospital discharge, three patients re-
ported mild intermittent self-resolving chest pain, prompting an 
emergency department visit in one patient. In two patients, per-
sistent albeit decreased subepicardial LGE was found on repeat 
cardiac MRI, appearing in a distribution similar to that seen on the 
initial MRI examination.

The pathophysiology of myocarditis in the setting of COVID-19 
is believed to in part relate to the cardiotropism of the SARS-CoV-2 
spike  protein  [15].  This  protein  is  theorized  to  use  the  angioten-
sin-converting enzyme 2 receptors of cardiomyocytes for cell en-
try.  Both  the  Moderna  and  Pfizer-BioNTech  vaccines  use  mRNA 
sequences that encode the spike protein [4, 15]. If causality is es-
tablished between the vaccines and myocarditis, the spike protein 
could potentially serve as a therapeutic target. However, myocar-
ditis has also been described after other antiviral vaccines [16]. Cor-
onary ectasia, as noted on echocardiography in one patient in this 
series,  resembles  descriptions  of  multisystem  inflammatory  syn-
drome in children (MIS-C) that has been reported in pediatric pa-
tients with COVID-19 [17]. This finding of ectasia resolved on fol-
low-up  echocardiography,  and  the  finding’s  clinical  significance 
is unclear. Nonetheless, the observation raises the possibility that 
myocarditis after vaccination relates to transient coronary chang-
es. The male sex of all five patients also suggests a possible func-
tional response to the vaccine that relates to a sex-linked gene.

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M R I   o f   P a t i e n t s   W i t h   M y o c a r d i t i s   A f t e r   C O V I D -19   V a c c i n a t i o n

This study has limitations. The presented data are descriptive 
and based on the retrospective assessment of only five patients. 
Additionally, the reported findings may be observed in myocar-
ditis  due  to  other  causes.  Comparison  was  not  performed  with 
a control group of patients with myocarditis in other settings to 
determine the findings’ specificity for myocarditis after COVID-19 
vaccination.  Further,  all  patients  underwent  cardiac  MRI  due  to 
clinical  suspicion  for  myocarditis.  Thus,  the  sample  represents 
a  high-risk  group,  which  may  have  introduced  a  selection  bias 
that contributed to the high frequency of abnormalities on car-
diac  MRI.  Milder  imaging  findings  may  have  been  observed  in 
patients  with  subclinical  presentations.  Finally,  although  oth-
er causes of myocarditis were excluded in all patients, it was not 
possible to provide definitely that the myocarditis in the five pa-
tients was caused by the COVID-19 vaccination.

In conclusion, we present cardiac MRI findings in five patients 
with myocarditis in the setting of recent COVID-19 mRNA vacci-
nation. All patients were male adolescents without known prior 
SARS-CoV-2 infection who presented within 4 days after the sec-
ond vaccine dose, and all patients had a favorable initial clinical 
course. All patients showed cardiac MRI findings typical of find-
ings of myocarditis of other causes, including LGE in all five pa-
tients  and  corresponding  myocardial  edema  in  four  patients. 
Short-term  follow-up  cardiac  MRI  in  two  patients  showed  per-
sistent,  albeit  decreased,  LGE.  Additional  investigation  is  war-
ranted to establish causality. Nonetheless, radiologists should be 
aware of the possible association and recognize the role of cardi-
ac MRI in the assessment of patients with suspected myocarditis 
after COVID-19 vaccination.

References
  1.  Johns Hopkins University of Medicine website. COVID-19 dashboard by the 
Center for Systems Science and Engineering (CSSE) at Johns Hopkins Uni-
versity  (JHU).  coronavirus.jhu.edu/map.html.  Published  2021.  Accessed 
September 2, 2021

  2.  Lancet  Commission  on  COVID-19  Vaccines  and  Therapeutics  Task  Force 
Members. Operation Warp Speed: implications for global vaccine security. 
Lancet Glob Health 2021; 9:e1017–e1021

  3.  Sharma O, Sultan AA, Ding H, Triggle CR. A review of the progress and chal-
lenges  of  developing  a  vaccine  for  COVID-19.  Front  Immunol  2020; 
11:585354

  4.  Ball P. The lightning-fast quest for COVID vaccines—and what it means for 

other diseases. Nature 2021; 589:16–18

  5.  Pardi N, Hogan MJ, Porter FW, Weissman D. mRNA vaccines: a new era in 

vaccinology. Nat Rev Drug Discov 2018; 17:261–279

  6.  Marshall M, Ferguson ID, Lewis P, et al. Symptomatic acute myocarditis in 
seven adolescents following Pfizer-BioNTech COVID-19 vaccination. Pedi-
atrics 2021; 148:e2021052478

  7.  Garcia JB, Ortega PP, Fernández JAB, León AC, Burgos LR, Dorta EC. Acute 
myocarditis  after  administration  of  the  BNT162b2  vaccine  against 
COVID-19. [in Spanish] Rev Esp Cardiol 2021; 74:812–814

  8.  Albert  E,  Aurigemma  G,  Saucedo  J,  Gerson  DS.  Myocarditis  following 

COVID-19 vaccination. Radiol Case Rep 2021; 16:2142–2145

  9.  Ministry  of  Health  website.  Surveillance  of  myocarditis  (inflammation  of 
the heart muscle) cases between December 2020 and May 2021 (includ-
ing). www.gov.il/en/departments/news/01062021-03. Published February 
6, 2021. Accessed July 6, 2021

 10.  CDC website. Myocarditis and pericarditis following mRNA COVID-19 vac-
cination.  www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myocarditis.
html. Published November 12, 2021. Accessed September 10, 2021

 11.  Ferreira VM, Schulz-Menger J, Holmvang G, et al. Cardiovascular magnetic 
resonance in nonischemic myocardial inflammation: expert recommenda-
tions. J Am Coll Cardiol 2018; 72:3158–3176

 12.  Bogaert J, Francone M. Cardiovascular magnetic resonance in pericardial 

diseases. J Cardiovasc Magn Reson 2009; 11:14

 13.  Daniels CJ, Rajpal S, Greenshields JT, et al.; Big Ten COVID-19 Cardiac Regis-
try Investigators. Prevalence of clinical and subclinical myocarditis in com-
petitive athletes with recent SARS-CoV-2 infection: results from the Big Ten 
COVID-19 Cardiac Registry. JAMA Cardiol 2021; 6:1078–1087

 14.  CDC website. Investigating long-term effects of myocarditis: how CDC is 
investigating myocarditis health effects after COVID-19 vaccination. www.
cdc.gov/coronavirus/2019-ncov/vaccines/safety/myo-outcomes.html.  Pub-
lished August 20, 2021. Accessed August 30, 2021

 15.  Siripanthong B, Nazarian S, Muser D, et al. Recognizing COVID-19-related 
myocarditis: the possible pathophysiology and proposed guideline for di-
agnosis and management. Heart Rhythm 2020; 17:1463–1471

 16.  Engler RJ, Nelson MR, Collins LC Jr, et al. A prospective study of the inci-
dence of myocarditis/pericarditis and new onset cardiac symptoms follow-
ing smallpox and influenza vaccination. PLoS One 2015; 10:e0118283

 17.  Matsubara D, Kauffman HL, Wang Y, et al. Echocardiographic findings in 
pediatric multisystem inflammatory syndrome associated with COVID-19 
in the United States. J Am Coll Cardiol 2020; 76:1947–1961

(Editorial Comment starts on next page)

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C h e l a l a   e t   a l .

Editorial Comment: Cardiac MRI as a Fundamental Tool in the Evaluation of Suspected Myocarditis After COVID-19 
mRNA Vaccination in Young Patients

In  this  study,  the  authors  investigate  the  relationship  between 
COVID-19  messenger  RNA  (mRNA)  vaccination  and  myocarditis  in 
young patients and describe the condition’s key clinical and diag-
nostic  elements.  This  work  could  have  a  major  impact  on  clinical 
practice  by  providing  additional  insights  into  this  emerging  clini-
cal condition, which might be misdiagnosed given its lack of clear 
symptoms. When assessing patients with suspected myocarditis af-
ter COVID-19 mRNA vaccination, referring clinicians and radiologists 
should consider the specific imaging features described in this study.
In particular, the article presents cardiac MRI as a leading tool 
for detecting features that help establish the diagnosis and guide 
appropriate clinical management. In the study, patients typically 
presented within 4 days after the second dose of the vaccine. As 
commonly  observed  in  other  forms  of  myocarditis,  cardiac  MRI 
techniques,  including  T1  and  T2  parametric  mapping  and  se-
quences for evaluation of myocardial edema and late gadolinium 
enhancement, served as useful methods for disease detection.

As all of the reported cases occurred in male patients, the au-
thors  advance  the  hypothesis  of  an  association  between  vac-
cine  response  and  sex-linked  genes.  Moreover,  given  that  the 

Pfizer-BioNTech  and  Moderna  vaccines  (BNT162b2  and  mRNA-
1273, respectively) use mRNA sequences that encode for the vi-
ral spike protein, the authors suggest that myocardial tropism in 
vaccine-related myocarditis might result from the action of this 
protein.  This  relation  may  help  guide  the  development  of  new 
therapeutic targets.

This series reports a small number of patients. Larger series, po-
tentially  obtained  by  combining  data  across  institutions,  could 
help identify differences between vaccine-related myocarditis and 
viral myocarditis. An additional helpful follow-up study would be 
to systematically evaluate patients for whom there was not a high 
suspicion for myocarditis to reduce this study’s selection bias.

Gloria Caredda, MD
Azienda Ospedaliero Universitaria 
Cagliari, Italy
careddagloria@gmail.com

The author declares that there are no disclosures relevant to the subject matter of this 
article.

doi.org/10.2214/AJR.21.27026

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