title: The apparent inversion time for optimal delayed enhancement magnetic resonance imaging differs between the right and left ventricles.
abstract: BACKGROUND
  Delayed post-contrast magnetic resonance (MR) imaging involves suppression of signal from myocardium using inversion times (TI) between 150-225 ms, when the myocardium appears dark and fibrotic scar appears bright. We noticed that at a TI optimized for signal suppression of the left ventricle (LV), the right ventricle (RV) appeared brighter.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the TI for signal suppression in RV compared to LV, and to try and identify the cause of this observation. Methods. We studied 31 patients (ages ranged from 17-79 years, 11 females) who had an MR scan on a 1.5 T GE scanner. Delayed post-contrast short-axis images were obtained 20 minutes after injection of 0.2 mmol/kg of intravenous gadolinium chelate. TI optimization was performed by acquiring a range of TI times within a single breath hold, in increments of 25 msec. The TI time that resulted in lowest signal for the RV arid LV was recorded.
  
  
  RESULTS
  With the imaging sequence employed, the TI leading to LV signal suppression ranged from 150-225 ms. At the TI that resulted in LV signal suppression, the corrected signal from the RV was significantly higher as compared to the LV (29 +/- 13 au vs. 15 +/- 8 au, p < 0.001). The findings were similar using only the body coil. The TI required to suppress the RV was usually < or =150 msec. The observation persisted before and after gadolinium infusion.
  
  
  CONCLUSIONS
  The TI for myocardial signal suppression appears to be different between LV and RV. Potential mechanisms include partial volume averaging with fat or blood pool (related to increased trabeculation) in the RV. Alternatively, increased blood pool signal (within Thebesian veins or arterioluminal communications) in RV compared to LV leads to altered TI times due to similar partial volume effects.
authors.affiliation: Division of Cardiology, Johns Hopkins University, Baltimore, Maryland 21287, USA.
authors.forename: Milind Y
authors.initials: MY
authors.lastname: Desai
authors.forename: Sandeep
authors.initials: S
authors.lastname: Gupta
authors.forename: Chandra
authors.initials: C
authors.lastname: Bomma
authors.forename: Harikrishna
authors.initials: H
authors.lastname: Tandri
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Foo
authors.forename: Joao A C
authors.initials: JA
authors.lastname: Lima
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002614:Chelating Agents; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged
chemical_list: D002614:Chelating Agents; D003287:Contrast Media; D019786:Gadolinium DTPA