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Technetium-99m sestamibi cavity/myocardium count ratio in the detection of left ventricular hypertrophy
Gulay Durmus Altun1, Osman Akdemir, Funda Ustun
1Trakya University, Faculty of Medicine, Department of Nuclear Medicine, Edirne, Turkey. gdurmusaltun@trakya.edu.tr
Insights
The cavity-to-myocardium (c/m) ratio on technetium-99m sestamibi images can help differentiate left ventricular hypertrophy (LVH) from normal geometry. This ratio shows potential for diagnosing LVH in patients without myocardial ischemia.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Left ventricular hypertrophy (LVH) is a significant risk factor for cardiovascular mortality and morbidity.
- Accurate differentiation of LVH from normal cardiac geometry is crucial for patient management.
Purpose of the Study:
- To evaluate the utility of the technetium-99m (99mTc) sestamibi cavity-to-myocardium (c/m) count ratio in distinguishing LVH from normal left ventricular geometry.
- To assess if the c/m ratio can differentiate between concentric and eccentric patterns of LVH.
Main Methods:
- Retrospective analysis of 72 patients, including 32 hypertensive patients with normal 99mTc sestamibi SPECT and echocardiography.
- Categorization of patients into four groups: normal geometry (n=47), concentric remodeling (n=3), eccentric LVH (n=13), and concentric LVH (n=9).
- Calculation of the c/m ratio from midventricular short-axis slices of dipyridamole-stress 99mTc sestamibi images.
Main Results:
- LVH was identified in 22 of 32 hypertensive patients.
- The c/m ratio was significantly lower in patients with LVH compared to those with normal geometry (0.05 ± 0.02 vs. 0.17 ± 0.08, p=0.001).
- A c/m ratio cutoff of <0.124 demonstrated 86% sensitivity, 64% specificity, and 68% accuracy for LVH detection. The c/m ratio correlated negatively with LV mass index, septal width, posterior wall thickness, and relative wall thickness.
Conclusions:
- The c/m ratio derived from 99mTc sestamibi images is a promising index for differentiating LVH from normal geometry in patients without myocardial ischemia.
- While both concentric and eccentric LVH showed reduced c/m ratios compared to normal geometry, the c/m ratio did not significantly differentiate between the two LVH patterns.
Background And Hypothesis:
Left ventricular hypertrophy (LVH) is an independent risk factor for cardiovascular mortality and morbidity. This study was designed to assess whether technetium-99m (99mTc) sestamibi cavity-to-myocardium count (c/m) ratio would differentiate LVH from normal geometry, and discriminate between the two patterns-concentric and eccentric--of LVH.
Methods:
In all, 72 patients including 32 hypertensive patients with both normal 99mTc sestamibi single-photon emission computed tomography imaging and good-quality echocardiographic recordings were studied retrospectively. Four different patterns of left ventricular (LV) geometry were defined: normal (n = 47), concentric remodeling (n = 3), eccentric LVH (n = 13), and concentric LVH (n = 9).
Results:
Left ventricular hypertrophy was detected in 22 of 32 hypertensive patients. The c/m ratio calculated on midventricular short-axis slices of dipyridamole-stress 99mTc sestamibi images was significantly decreased in patients with LVH compared with subjects with normal geometry (0.05 +/- 0.02 vs. 0.17 +/- 0.08, p = 0.001). A c/m ratio of <0.124 yielded a sensitivity of 86%, a specificity of 64%, and an overall diagnostic accuracy of 68% for detecting LVH. Negative correlations of c/m ratio were found to LV mass-index (r = -0.44, p = 0.004), septal width (r = -0.42, p = 0.008), posterior wall thickness (r = -0.39, p = 0.001), and relative wall thickness (r = -0.40, p = 0.001). Multiple linear regression analysis revealed that LV mass index was the single independent predictor of c/m ratio. Although both groups with concentric and eccentric LVH had a significantly lower mean c/m ratio than those with normal geometry (p = 0.01 and p = 0.01, respectively), no significant difference of c/m ratio was found between the two patterns of LVH.
Conclusion:
A new index, c/m ratio on 99mTc sestamibi images, has a potential to discriminate between LVH and normal geometry in subjects free of myocardial ischemia.