Paradoxical septal motion is commonly described in patients with pulmonary hypertension and right ventricular pressure overload during echocardiographic examinations, but rarely reported during myocardial perfusion studies.
Purpose: Our study aimed at documentation of septal flattening during rest gated SPECT imaging with echocardiographic confirmation of pulmonary hypertension or right ventricular overload. Methods: The study included 68 patients [35 males, 33 females], mean age 49+11 years with echocardiographic proven pulmonary hypertension. All patients were subjected to conventional echocardiography and rest gated SPECT perfusion scanning following injection of 555 MBq Tc-99m tetrofosmin using triple head general purpose large field scintillation gamma camera.
Results: The study population divided into 2 groups; group A: patients showed septal flattening in gated SPECT [56 patients; 82%] and
group B: patients did not show septal flattening [12 patients; 18%]. Septal flattening in gated SPECT significantly correlated with pulmonary artery pressure (85.7+16.4 mmHg for group A
Corresponding Author:
Shahenda Salem, MD.Associate professor of Nuclear Medicine Cairo University, Cairo, Egypt. Email: afssalem@yahoo.com compared to 50+12.5 mmHg for group B, P<0.001), pulmonary artery diameter (37+0.6 mm for group A compared to 21+0.4 mm for group B, P<0.02), LV diastolic volume (156.4+24 ml for group A compared to 111 +12.5 ml for group B, P<0.004) and RV tracer uptake. There was no significant correlation between septal flattening and septal thickness (0.92+0.16 cm for group A compared to 0.81 +0.17 cm for group B, P<0.3) or LV ejection fraction (60+6 % for group A compared to 58+9 % for group B, P<0.2).
Conclusion: Flattening of the interventricular septum [D-shape left ventricle] in gated SPECT imaging correlated with echocardiographic finding of septal flattening and associated with right ventricular overload. The shape of the interventricular septum and the term of septal flattening, if present, should be routinely reported during interpretation of gated SPECT studies similar to echocardiographic descriptions in patients with suspected right ventricular overload.