Visualisation of sodium-iodide symporter.
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Adenocarcinoma, Mucinous↗
Biomedical subjects
Ignasi Carrio
Publications and source records attributed to Ignasi Carrio.
Improved quantification in 123I cardiac SPECT imaging with deconvolution of septal penetration.
OBJECTIVES: (123)I is becoming an important radionuclide for cardiac imaging. Multiple, low-abundance, high-energy photons associated with (123)I imaging can cause septal penetration in the collimators and degrade quantification of the (123)I cardiac uptake. This study presents a method for the deconvolution of septal penetration (DSP) for improving quantification in (123)I cardiac single photon emission computed tomography (SPECT). METHODS: Distance-dependent point spread functions were measured for low-energy high-resolution collimators on a dual-head SPECT system. The measured point spread functions were used in two-dimensional (2-D) and three-dimensional (3-D) models of the collimator response, respectively. 2-D DSP and 3-D DSP were then developed and implemented using iterative reconstruction. A cardiac torso phantom with an internal calibration source was designed with various heart-to-calibration ratios (HCRs) simulating different levels of a patient's uptake. SPECT acquisitions of the phantom were performed using optimized acquisition and processing parameters for (123)I cardiac SPECT. HCRs were calculated using planar projection and tomographic reconstructions. The paired t-test and regression analysis were used to compare the HCRs given by different calculation methods. RESULTS: SPECT produced more accurate HCRs than planar imaging. The slopes of the regression lines for SPECT using filtered back-projection were statistically significantly higher than those for planar imaging (0.2118 +/- 0.0297 vs. 0.0819 +/- 0.0070, P = 0.0001). 2-D DSP and 3-D DSP yielded similar HCRs that were close to the true HCR. The slopes of the regression lines for 2-D DSP and 3-D DSP were 0.9203 +/- 0.0523 and 0.9101 +/- 0.0304, respectively. The DSP HCRs were significantly more accurate than those calculated without DSP (P < 0.0001). CONCLUSION: DSP significantly improves quantification in (123)I cardiac SPECT imaging. 2-D DSP with its less computational burden shows promise for implementation in clinical practice so as to allow the use of the widely available low-energy, high-resolution collimators for quantitative I cardiac SPECT imaging.
Algorithms↗
Role of noninvasive antimyosin imaging in infants and children with clinically suspected myocarditis.
UNLABELLED: Endomyocardial biopsy is an invasive procedure, often performed on children for the diagnosis of myocarditis, and is not without risk. Therefore, a noninvasive test of adequate diagnostic accuracy is highly desirable. We evaluated the role of antimyosin scintigraphy in infants and children with clinically suspected myocarditis. METHODS: Forty patients (age range, 2 mo to 14 y) with suspected myocarditis underwent (111)In-antimyosin scintigraphy. All patients were clinically followed for 29 +/- 17 mo; 21 patients underwent serial antimyosin scans (3.8 +/- 1.7 per patient). The antimyosin uptake was assessed by heart-to-lung ratio (HLR). The scan results were compared with endomyocardial biopsy results in 22 patients. RESULTS: Thirty-five of the 40 patients showed abnormal antimyosin findings; 17 patients showed intense myocardial antimyosin uptake (HLR > 2). The HLR was higher in patients presenting within the first 2 mo of illness (2.09 +/- 0.43 vs. 1.74 +/- 0.34, P = 0.01). Of 22 patients with endomyocardial biopsy, 17 demonstrated myocarditis. All 9 patients who had an HLR > 2 and underwent endomyocardial biopsy had histologic evidence of myocarditis. Of the remaining 13 patients with HLR < 2, 8 had biopsy-verified myocarditis (62%). The intensity of antimyosin uptake was the major determinant of survival in children, with a relative risk of 18 (confidence interval, 1.34-242; P = 0.027). High antimyosin uptake (HLR > 2) seen within 2 mo of the onset of symptoms was associated with a higher mortality rate. The survivors with an HLR > 2 and those with an HLR < 2 showed a high likelihood of complete functional recovery. Furthermore, the patients with serial antimyosin scans having persistently positive findings showed a poor clinical outcome. CONCLUSION: Intense myocardial uptake of antimyosin antibody is a reliable indicator of myocarditis in infants and children. Severe myocardial damage detected in the early phase of disease is associated with a higher mortality rate. The persistence of antimyosin uptake is associated with poor clinical outcomes.
Adolescent↗
Optimized acquisition and processing protocols for I-123 cardiac SPECT imaging.
BACKGROUND: Deconvolution of septal penetration (DSP) has been developed to improve quantification so as to allow the use of low-energy high-resolution collimators for iodine 123 cardiac single photon emission computed tomography (SPECT) imaging. The purpose of this study is to optimize its acquisition and processing protocols. METHODS AND RESULTS: Planar images of a 9-compartment phantom loaded with variable radioactive concentrations were acquired to derive optimal scatter compensation scaling factors for 20% and 15% photopeak energy window configurations, respectively. A cardiac phantom, loaded with high and low heart-to-calibration ratios (HCRs), respectively, was imaged with both configurations. Repeated acquisitions were done for medium-energy all-purpose collimators for comparison. Critical frequencies for Butterworth filtering were optimized by use of defect contrast and normal short-axis uniformity as selection indices. HCRs were calculated with planar projection and different reconstruction methods, respectively, and then compared with the true HCRs. SPECT produced more accurate HCRs than planar imaging. With the optimized parameters for scatter compensation and filtering, the 2 energy window configurations yielded similar results. Iterative reconstructions with DSP yielded more accurate HCRs than other reconstructions without DSP. CONCLUSION: The optimized protocols based on DSP show promise that quantification of I-123 cardiac SPECT imaging can be achieved with the widely available low-energy high-resolution collimators.
Algorithms↗