title: Pericardial abscess occurring after tuberculous pericarditis: image morphology on computed tomography and magnetic resonance imaging.
abstract: OBJECTIVE
  To study the image morphology on computed tomography (CT) and magnetic resonance imaging (MRI) of pericardial abscess, an uncommon complication of tuberculous pericarditis.
  
  
  METHODS
  In a 9-year period, 120 patients with clinical and imaging features of constrictive pericarditis were retrospectively reviewed. Of them, 13 patients (age range, 1-51 years; seven females, six males), who had a pericardial mass on echocardiography, and were subjected to CT (11 patients) and MRI (7 patients), were included as subjects of the present study. Five patients underwent both the investigations. The intra-lesional morphology, location, extent, mass effect on adjacent cardiac chambers, secondary effects on the atria and venae cavae, and pericardial thickness were studied. Histopathological confirmation of tubercular infection was available in nine patients. In the remaining four patients, the diagnosis was based on typical extra-cardiac manifestations of tuberculosis.
  
  
  RESULTS
  A total of 15 abscesses were detected. CT showed a lesion with a hypodense core and an enhancing rim in all patients. On spin-echo T1-weighted MRI, 57% of the paients had a lesion with a hyperintense core, suggesting an exudative process. Seventy-one percent of patients showed a lesion with a hyperintense core on T2-weighted MRI, while one lesion was hypointense. Post-gadolinium MRI was performed in two patients and showed an enhancing rim in both, with enhancing septa in one. The predominant site of involvement was in the right atrioventricular (AV) groove (77%). Localized tamponade, suggested by the presence of mass effect on an adjacent cardiac chamber, was noted in nine (69%) cases, with proximal atrial dilatation in 78% of them. Four other patients (31%) had atrial dilatation without a localized mass effect.
  
  
  CONCLUSIONS
  Pericardial abscess is an uncommon complication of constrictive pericarditis. Tuberculosis was responsible for abscess formation in all cases in this study. The majority of the lesions are located in the right AV groove with imaging features suggestive of localized tamponade. The presence of a hypointense core on T2-weighted MRI may suggest a tubercular aetiology.
authors.affiliation: Department of Cardiovascular Radiology, Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi 110029, India.
authors.forename: G S
authors.initials: GS
authors.lastname: Gulati
authors.forename: S
authors.initials: S
authors.lastname: Sharma
mesh_terms: D000038:Abscess / Q000175:diagnosis* / Q000209:etiology; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010495:Pericarditis, Tuberculous / Q000150:complications / Q000175:diagnosis*; D010496:Pericardium; D014057:Tomography, X-Ray Computed / Q000379:methods