Flattening of the interventricular septum (D-shaped left ventricle) in addition to high right ventricular tracer uptake and increased right ventricular volume found on gated SPECT studies strongly correlates with right ventricular overload.
BACKGROUND
Flattening of the interventricular septum (D-shaped left ventricle) detected during echocardiographic examination is correlated with significant right ventricular (RV) overload. There are no reports of this finding with cardiac gated single photon emission computed tomography (SPECT) imaging. We report an observational study correlating this finding with the presence of RV overload.


RESULTS
Retrospectively, we compared 8 cases with flattening of the interventricular septum on cardiac gated SPECT imaging for which echocardiographic correlations and clinical data were available regarding the presence of RV overload. All patients but 1 had pulmonary hypertension ranging from 42 to 52 mm Hg measured by echocardiographic Doppler studies. All patients but 1 had reasons for RV overload (chronic obstructive pulmonary disease in 3, history of atrial septal defect in 3, pulmonary embolism in 1, and obstructive sleep apnea in 1). Septal flattening present on gated SPECT images was seen in 50% of the cases by echocardiography. Other signs of RV overload (RV enlargement, RV hypertrophy) were observed by echocardiography in 5 patients and by the gated SPECT in 7 patients.


CONCLUSIONS
The presence of interventricular septal flattening on gated SPECT studies correlates with RV overload and should be routinely assessed during interpretation of gated SPECT studies.
Movahed
Mohammad Reza
MR
Department of Medicine, Division of Cardiology, University of California-Irvine Medical Center, 101 The City Drive, Orange, CA 92868-4048, USA. mmovahed@uci.edu
Hepner
Absalom
A
Lizotte
Paul
P
Milne
Norah
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006346:Heart Septum / Q000000981:diagnostic imaging* / Q000378:metabolism; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014463:Ultrasonography; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging* / Q000378:metabolism
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin