SPECT-CT in Differentiating Metastatic and Degenerative Lesions of the Spine

@#Introduction: The purpose of this study was to determine the usefulness of SPECT-CT in differentiating metastatic and degenerative disease of the spine. Methods: Twenty-eight patients aged 50 years and above diagnosed with various cancers were referred for whole body (WB) planar bone scintigraphy. Those with a maximum three foci of tracer uptake in the spine were selected for the study. SPECT-CT of these areas of uptake was performed and the lesions were classified as degenerative, indeterminate or metastasis. A repeat study (WB planar bone scintigraphy and SPECT-CT) was performed between 3 to 12 months later. These areas of uptake were reassessed and compared with the first WB planar bone scintigraphy and SPECT-CT. The second SPECT-CT was used as the standard for the diagnosis. Results: Thirty-seven lesions in 28 patients were assessed. The sensitivity of the first WB planar bone scintigraphy, second WB planar bone scintigraphy and first SPECT-CT is 75%, 62.5% and 75% respectively. The specificity of the first WB planar bone scintigraphy, second WB planar bone scintigraphy and first SPECT-CT is 86%, 93%, 90% respectively. There was 2.7% of ‘indeterminate lesion’ in the first WB planar bone scintigraphy, 5.4% in the second WB planar bone scintigraphy, and 5.4% in the first SPECT-CT. The indeterminate lesions were resolved in the second SPECT-CT. Conclusion: SPECT- CT is useful in differentiating degenerative disease from metastatic lesions in the spine.

Diffusion Tensor Imaging of Leukoaraiosis, Normal Appearing Brain Tissue, and Normal Brain Tissue

Diffusion Tensor Imaging (DTI) is an advanced magnetic resonance imaging (MRI) technique. DTI provides quantitative information at microstuructural level via its parameter indices e.g. mean diffusivity (MD) and fractional anisotropy (FA). It also allows for visualization of neuron fibres through a specific technique called fibre tractography. Leukoaraiosis is an asymptomatic pathological condition of the brain white matter which appears hyperintense on T2-weighted MRI images. Association of leukoaraiosis with age and ischemic heart disease have been previously reported. The objective of this study is to compare MD and FA values measured in various areas of the brain white matter (WM), grey matter (GM), and cerebrospinal fluid (CSF) in humans using DTI. 30 subjects with leukoaraiosis and 12 subjects without leukoaraiosis underwent brain scan using GE 1.5 Tesla MRI system. Region of interests were located in the CSF and various WM and GM areas. Comparison of MD and FA values was made between leukoaraiosis tissue (LA) and normal appearing brain tissue (NABT) measured within the same leukoaraiosis subjects, and with normal brain tissue (CONTROL) of healthy control subjects. LA demonstrated a significantly higher MD and lower FA compared to NABT and CONTROL in frontal and occipital WM areas. No differences were observed in MD in any brain region between NABT and CONTROL. Whereas no differences were observed in FA between NABT and CONTROL except in the occipital WM. Fibre tractography showed 31.7% to 56.1% lesser fibre tracts in LA subjects compared to CONTROL subjects. Significant differences were found between pathological tissue compared to normal appearing brain tissue and normal brain tissue. Fibre tractography exposed reduced number of neural fibres in leukoaraiosis subjects as compared to normal subjects.

Clinical Determinants of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Differentiated Thyroid Cancer Patients with Elevated Thyroglobulin and Negative 131Iodine Whole Body Scans after 131Iodine Therapy

Background: A cross-sectional prospective study has been conducted on differentiated thyroid cancer (DTC) patients using negative 131Iodine (131I) whole body scans and elevated thyroglobulin (Tg) levels. The main objective of this research was to determine the prevalence of the conversion of differentiated to dedifferentiated thyroid cancer patients during follow up at the Hospital Kuala Lumpur. It has been demonstrated that fluorodeoxyglucose (FDG) uptake is inversely proportional to the iodine concentration and to differentiation of the cells. Methodology: Thirty-five patients with histologically proven DTC that have undergone total or near total thyroidectomy, and post 131I radioactive iodine ablation therapy, were selected and prospectively analysed. The patients also had to show at least one negative whole body scan and Tg levels of 10 μg/L and above. The results of the FDG-Positron Emission Tomography/Computed Tomography (PET/CT) were then studied to determine the association and the predictors influencing the outcome by using univariable and multivariable analyses. Results: Out of the thirty-five patients, 60% of them (twenty-one) showed positive results and 40% (fourteen) showed negative. Age, gender, and type of histopathology (HPE) showed significant associations with the positive results of the FDG-PET/CT. The results also showed no correlations observed between the Tg levels and standardised uptake value (SUV)max in the DTC patients with positive disease findings in the FDG-PET/CT. The predictor for this study was age. Conclusion: The prevalence of the conversion of differentiated to dedifferentiated thyroid cancer among patients with negative 131I and elevated Tg was 60%, with age as the predictor. DTC patients aged 45 year-old and older were seven times more likely to have positive results of FDG-PET/CT imaging.