title: Serial FDG-PET scans help to identify steroid resistance in cardiac sarcoidosis.
abstract: BACKGROUND
  Cardiac sarcoidosis (CS) is increasingly being recognized. Immunosuppression with corticosteroids is the mainstay of therapy. But the optimal dose of steroids and how to assess response to therapy is not known. Prognosis is poor if these patients are untreated or undertreated. Fluorine-18-flurodeoxyglucose positron emission computed tomography (18FDG-PET CT) is a sensitive tool in diagnosing CS. It correlates closely with the level of granulomatous inflammation and can be used to monitor response to therapy.
  
  
  METHODS
  We identified 15 patients (6 women; mean age, 42.9±12.5years) based on histopathological diagnosis. All had a baseline and follow-up fasting18FDG-PET CT scans before and after steroid therapy. Non-responders were defined as those in whom ventricular arrhythmias, symptoms of HF and left ventricular systolic function and/or ventricular arrhythmias did not improve or worsened despite steroid therapy. FDG uptake of involved myocardium and lymph nodes (LN) was compared in clinical responders and non-responders on follow-up.
  
  
  RESULTS
  Of the 15 patients, 4 were clinical non-responders to steroid therapy. Follow-up18FDG-PET CT was performed at 125.8±54.2days after the initiation of steroid therapy. Myocardial maximum standardized uptake of FDG (SUVmax) value decreased significantly in responders (p=0.004) while there was an increase in non-responders (p<0.05) on follow-up. Number of left ventricle (LV) segments with FDG uptake significantly decreased in responders (p=0.007), and on increasing trend in non-responders (p=0.465). Heterogeneous FDG uptake on baseline PET scan, increase in intensity as well as area of myocardial inflammation on follow-up PET scan was associated with poor clinical outcome despite steroid therapy.
  
  
  CONCLUSIONS
  Serial18FDG-PET CT scans can be used to monitor steroid therapy in active CS. Increase in PET uptake after steroid therapy correlates with poor clinical outcome. Repeat PET scan may help to predict steroid-resistant CS and the need for up-titration of immunosuppressive therapy among poor responders to initial therapy.
authors.affiliation: Department of Cardiac Electrophysiology, CARE Hospitals, Hyderabad, India.
authors.forename: Abhijeet B
authors.initials: AB
authors.lastname: Shelke
authors.affiliation: Department of Nuclear Medicine, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, India.
authors.forename: Hrushikesh U
authors.initials: HU
authors.lastname: Aurangabadkar
authors.affiliation: UCLA Cardiac Arrhythmia Center, Ronald Reagan UCLA Medical Center, Los Angeles, CA, United States.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Bradfield
authors.affiliation: Department of Nuclear Medicine, Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, India.
authors.forename: Zakir
authors.initials: Z
authors.lastname: Ali
authors.affiliation: UCLA Cardiac Arrhythmia Center, Ronald Reagan UCLA Medical Center, Los Angeles, CA, United States.
authors.forename: K Shiv
authors.initials: KS
authors.lastname: Kumar
authors.affiliation: Department of Cardiac Electrophysiology, CARE Hospitals, Hyderabad, India. Electronic address: calambur1@gmail.com.
authors.forename: Calambur
authors.initials: C
authors.lastname: Narasimhan
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D000328:Adult; D009202:Cardiomyopathies / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D015331:Cohort Studies; D004351:Drug Resistance; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D019275:Radiopharmaceuticals; D012507:Sarcoidosis / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D000305:Adrenal Cortex Hormones; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Cardiac sarcoidosis; Management of sarcoidosis; PET scan; Steroid resistance; Ventricular arrhythmias