title: Coronary MR imaging: effect of timing and dose of isosorbide dinitrate administration.
abstract: OBJECTIVE
  To quantify the effect of sublingual isosorbide dinitrate (ISDN) administration on coronary magnetic resonance (MR) imaging.
  
  
  METHODS
  Written informed consent was obtained from all participants, and the HIPAA-compliant protocol was approved by the Institutional Review Board. Coronary MR imaging was performed at 1.5 T before and after administration of ISDN (2.5 or 5 mg) in 25 healthy adult volunteers (mean age, 23 years +/- 4; nine men, 16 women) with three-dimensional targeted (n = 20, randomized into four groups) or whole-heart (n = 5) acquisitions with gradient-recalled echo (GRE) or balanced steady-state free precession (SSFP) sequences. Image quality was assessed by two cardiologists on a four-point scale. Signal-to-noise ratio (SNR), vessel diameter, and vessel sharpness were characterized. A linear mixed-effects model was used for data analysis. A P value of less than .05 was considered to indicate a significant difference.
  
  
  RESULTS
  The maximum SNR enhancement with 5 mg of ISDN (GRE: 22.0% +/- 10.7%; SSFP: 20.1% +/- 6.0%) was similar (P > .05) to that with 2.5 mg (GRE: 21.9% +/- 5.4%; SSFP: 19.1% +/- 3.0%). However, the time to maximum SNR enhancement for the 5-mg dose (15.5 minutes +/- 6.0) was earlier (P < .01) than that for 2.5 mg (23.5 minutes +/- 6.7). The increase in vessel diameter with 5 mg of ISDN was greater than that with 2.5 mg (P < .05 for both GRE and SSFP sequences). The coronary images were sharper after ISDN administration (P < .03). Subjective image quality score significantly improved after ISDN administration for GRE images (P < .05 for both doses) but was similar for SSFP images (P = .24 for 2.5 mg; P = .27 for 5 mg). Whole-heart coronary SNR was improved about 10% after ISDN administration (P < .05).
  
  
  CONCLUSIONS
  Sublingual ISDN improves coronary MR imaging SNR. Practitioners need to consider the dose and temporal effects of ISDN when performing coronary MR imaging.
authors.affiliation: Cardiovascular Division, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Hu
authors.forename: Michael L
authors.initials: ML
authors.lastname: Chuang
authors.forename: Long H
authors.initials: LH
authors.lastname: Ngo
authors.forename: Christian T
authors.initials: CT
authors.lastname: Stoeck
authors.forename: Dana C
authors.initials: DC
authors.lastname: Peters
authors.forename: Kraig V
authors.initials: KV
authors.lastname: Kissinger
authors.forename: Beth
authors.initials: B
authors.lastname: Goddu
authors.forename: Lois A
authors.initials: LA
authors.lastname: Goepfert
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Manning
authors.forename: Reza
authors.initials: R
authors.lastname: Nezafat
mesh_terms: D000286:Administration, Sublingual; D003331:Coronary Vessels / Q000033:anatomy & histology*; D005260:Female; D006321:Heart / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007548:Isosorbide Dinitrate / Q000008:administration & dosage*; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D014665:Vasodilator Agents / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D014665:Vasodilator Agents; D007548:Isosorbide Dinitrate