1,721,359 research outputs found

    Fusion imaging in nuclear medicine - Applications of dual-modality systems in oncology

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    Medical imaging has become of the utmost importance in evaluating patients with cancer. Single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are accurate methods for detecting cancer and related metabolic abnormalities, but they often do not provide the anatomical landmarks needed to precisely localize lesions. Magnetic resonance imaging (MRI) and computed tomography (CT) scan, on the other hand, offer excellent anatomic detail but are less sensitive because they do not provide functional detail. Fusion imaging combines functional studies with morphological ones, so overcoming the drawbacks of both modalities. Software-based fusion of independently performed scintigraphic and radiological images has proven time consuming and impractical for routine use. Recently, dual-modality integrated imaging systems (SPECT/CT and PET/CT) have been developed: the acquired images are coregistered by means of the hardware in the same session. These new devices can be particularly useful for tumour imaging. The anatomical images provide precise localization and allow the exclusion of disease in sites of physiologic tracers' accumulation for SPECT and PET findings. Hybrid imaging in oncological applications has been very encouraging, indicating that these systems are suited for routine use in clinical practice. In fact, fused images provide additional information that improves diagnostic accuracy and impacts on patient management

    The value of semi-quantitative analysis of 123I-FP-CIT SPECT in evaluating patients with parkinson's disease

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    123I-FP-CIT SPECT binding to striatal dopamine transporter (DAT) is markedly reduced in patients with Parkinson's disease (PD) and it may also help in identifyng pre-symptomatic nigrostriatal dysfunction in subjects at risk. This study used semi-quantitative analysis of 123I-FP-CIT SPECT to evaluate the possibility of a more extensive and earlier diagnosis of dopaminergic damage. We used qualitative visual assessment and semi-quantitative measures of striatal DAT binding using 123I-FP-CIT SPECT in 154 patients with suspected PD. A control group comprised 18 people age-matched to the PD group whose follow-up disclosed essential tremor. Abnormal striatal 123I-FP-CIT uptake was evident in 134 out of 154 patients (87%). Qualitative visual assessment showed striatal dopaminergic 123I-FP-CIT uptake was significantly reduced in 60.4% (controlateral putamen to the symptoms), in 31.3% (caudate nucleus) and in 8.3% (ipsolateral basal ganglia to the symptoms). Semi-quantitative analysis showed the following results: 32.8%, 50.7% and 16.5% respectively. We compared these two assessments and their correlation with PD clinical progression. At 24 month follow-up, patients with greater dopaminergic damage at semiquantitative analysis showed a more severe motor disability. Our findings indicate that 123-FP-CIT SPECT with semiquantitative analysis can offer a more accurate characterization of the dopaminergic damage in patients with suspected Parkinson's disease

    Combined morphological, [1H]-MR spectroscopic and contrast-enhanced imaging of human prostate cancer with a 3-Tesla scanner: preliminary experience

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    Purpose. The objective of this study was to explore the feasibility of combined morphological magnetic resonance imaging (MRI), [H-1]magnetic resonance spectroscopic imagine, (MRSI) and quantitative dynamic contrast-enhanced MRI (DCE-MRI) of human prostate cancer at 3 Tesla using a pelvic phased-array coil. Materials and methods. MRI, MRSI and DCE-MRI with a 3-Tesla whole-body scanner were. performed in 30 patients with biopsy-proven prostate cancer before radical prostatectoray. High-resolution T2-weighted turbo spin echo (TSE) images were evaluated for visualisation of the peripheral zone, central gland, visibility of the cancer lesion, prostatic capsule delineation and overall image quality according to a five-point scale. Relative levels of the prostate metabolites citrate, choline and creatine were determined in cancer and in the normal peripheral zone (PZ) and central gland (CG). Spectra were also evaluated for the separation of the signal of citrate, choline and creatine and suppression of lipid and water signals. Time-intensity curves were obtained for prostatic cancer and healthy PZ and CG from DCE-MRI. Finally, time of arrival, time to peak, maximum enhancement and wash-in rate in cancer, normal PZ and CG were calculated. Results. The high signal-to-noise ratio (SNR) at 3 Tesla provided T2-weighted TSE images with excellent anatomical detail (in-plane voxel size of 0.22x0.22 mm) and good T2 contrast. The increased spectral resolution was sufficient to separate the choline and creatine resonances and allow delineation of the four peaks of citrate resonance. The (choline + creatine)/citrate ratio was elevated in cancer in comparison with PZ and CG (p<0.001). Dynamic contrast-enhanced images showed good temporal resolution. All parameters obtained from DCE-MRI showed a statistically significant (P<0.05) difference between cancer tissue and normal PZ and CG. Wash-in rate and (choline+creatine)/citrate ratio were significantly correlated (r=0.713, P=0.001) in PZ cancer, whereas the correlation was not significant (r=0.617, P=0.06) in CG and in PZ (r=0.530, P=0.08). Conclusions. It is possible to perform MRI of prostate cancer at 3 Tesla using a pelvic phased-array coil with high spatial, temporal and spectral resolution. The combination of vascular information from DCE-MRI and metabolic data from MRSI has excellent potential for improved accuracy in delineating and staging prostate carcinoma. These results suggest that high magnetic field strengths offer the possibility of studying prostate cancer without use of an endorectal coil
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