A 54-year-old male presented to the emergency department with acute chest pain and breathlessness. Electrocardiogram showed ST elevation in anterior leads and bedside echocardiography showed severe left ventricular systolic dysfunction. Blood investigations showed elevated cardiac biomarkers. However, coronary angiogram revealed normal coronary arteries which excluded coronary artery disease. The patient was tested negative for COVID-19 infection. A clinical diagnosis of acute myocarditis was made. Cardiac Magnetic resonance imaging (MRI) revealed perimyocardial early and late gadolinium enhancement with edema in multiple regions including the septum, which were consistent with acute myocarditis. He was then referred for 68Ga-DOTANOC to look for active inflammatory process. 68Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) [Figure 1a-c, d2] revealed diffuse heterogeneously increased radiotracer uptake in the entire left ventricular myocardium. 99mTc-Sestamibi myocardial perfusion imaging [Figure 1 d1] showed a small perfusion defect in distal inferior wall. The patient was managed symptomatically and was started on oral corticosteroid therapy. The patient improved symptomatically.
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Figure 1: Axial CT (a), PET (b), and fused PET/CT (c) images showed diffuse heterogeneously increased tracer uptake in the entire left ventricular myocardium. Conventional slices of short axis (left panel), vertical long axis (middle panel), and horizontal long axis (right panel) showed a small perfusion defect in distal inferior wall on 99mTc-MIBI perfusion study (d1) and diffuse radiotracer uptake in the left ventricular myocardium on 68Ga-DOTANOC PET (d2). PET: Positron emission tomography, CT: Computed tomography
Inflammatory cells shows somatostatin receptor (SSTR) expression, most commonly SSTR type 2.[1] SSTR imaging in myocardial inflammation has been reported previously in few cases. Baghel et al.[2] showed mild diffuse heterogeneous 68Ga-DOTANOC uptake in the left ventricular myocardium in a case of myocarditis. Amini et al.[3] performed 99mTc-Octreotide SPECT/CT in a patient with myocarditis, revealing diffuse tracer uptake in the left ventricular myocardium. Lapa et al.[4] compared SSTR PET/CT with MRI for the detection of myocardial inflammation, which showed a close spatial relationship between macrophage concentration and structural changes. Imaging has been tried with 99mTc-depreotide also, which also revealed diffuse tracer uptake in myocarditis.[5]
SSTR imaging can act as a surrogate marker of active inflammation, especially in cases where endomyocardial biopsy is difficult. Other advantages of SSTR imaging include, but not limited to, decide site of biopsy, assessing response to therapy and prognostication.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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