Current Issue : October - December Volume : 2013 Issue Number : 4 Articles : 5 Articles
Background: The heart is subject to structural and functional changes with advancing age. However, the\r\nmagnitude of cardiac age-dependent transformation has not been conclusively elucidated.\r\nMethods: This retrospective cardiac magnetic resonance (CMR) study included 183 subjects with normal structural\r\nand functional ventricular values. End systolic volume (ESV), end diastolic volume (EDV), and ejection fraction (EF)\r\nwere obtained from the left and the right ventricle in breath-hold cine CMR. Patients were classified into four age\r\ngroups (20ââ?¬â??29, 30ââ?¬â??49, 50ââ?¬â??69, and =70 years) and cardiac measurements were compared using Pearsonââ?¬â?¢s rank\r\ncorrelation over the four different groups.\r\nResults: With advanced age a slight but significant decrease in ESV (r=-0.41 for both ventricles, P<0.001) and EDV\r\n(r=-0.39 for left ventricle, r=-0.35 for right ventricle, P<0.001) were observed associated with a significant increase\r\nin left (r=0.28, P<0.001) and right (r=0.27, P<0.01) ventricular EF reaching a maximal increase in EF of +8.4%\r\n(P<0.001) for the left and +6.1% (P<0.01) for the right ventricle in the oldest compared to the youngest patient\r\ngroup. Left ventricular myocardial mass significantly decreased over the four different age groups (P<0.05).\r\nConclusions: The aging process is associated with significant changes in left and right ventricular EF, ESV and EDV\r\nin subjects with no cardiac functional and structural abnormalities. These findings underline the importance of\r\nusing age adapted values as standard of reference when evaluating CMR studies....
Background: Magnetic resonance imaging (MRI) studies typically employ either a single expert or multiple readers\r\nin collaboration to evaluate (read) the image results. However, no study has examined whether evaluations from\r\nmultiple readers provide more reliable results than a single reader. We examined whether consistency in image\r\ninterpretation by a single expert might be equal to the consistency of combined readings, defined as independent\r\ninterpretations by two readers, where cases of disagreement were reconciled by consensus.\r\nMethods: One expert neuroradiologist and one trained radiology resident independently evaluated 102 MRIs of the\r\nupper neck. The signal intensities of the alar and transverse ligaments were scored 0, 1, 2, or 3. Disagreements were\r\nresolved by consensus. They repeated the grading process after 3ââ?¬â??8 months (second evaluation). We used kappa\r\nstatistics and intraclass correlation coefficients (ICCs) to assess agreement between the initial and second\r\nevaluations for each radiologist and for combined determinations. Disagreements on score prevalence were\r\nevaluated with McNemarââ?¬â?¢s test.\r\nResults: Higher consistency between the initial and second evaluations was obtained with the combined readings\r\nthan with individual readings for signal intensity scores of ligaments on both the right and left sides of the spine.\r\nThe weighted kappa ranges were 0.65-0.71 vs. 0.48-0.62 for combined vs. individual scoring, respectively. The\r\ncombined scores also showed better agreement between evaluations than individual scores for the presence of\r\ngrade 2ââ?¬â??3 signal intensities on any side in a given subject (unweighted kappa 0.69-0.74 vs. 0.52-0.63, respectively).\r\nDisagreement between the initial and second evaluations on the prevalence of grades 2ââ?¬â??3 was less marked for\r\ncombined scores than for individual scores (P = 0.039 vs. P = 0.004, respectively). ICCs indicated a more reliable\r\nsum score per patient for combined scores (0.74) and both readersââ?¬â?¢ average scores (0.78) than for individual scores\r\n(0.55-0.69).\r\nConclusions: This study was the first to provide empirical support for the principle that an additional reader can\r\nimprove the reproducibility of MRI interpretations compared to one expert alone. Furthermore, even a moderately\r\nexperienced second reader improved the reliability compared to a single expert reader. The implications of this for\r\nclinical work require further study....
Background: This paper presents a method that registers MRIs acquired in prone position, with surface topography\r\n(TP) and X-ray reconstructions acquired in standing position, in order to obtain a 3D representation of a human torso\r\nincorporating the external surface, bone structures, and soft tissues.\r\nMethods: TP and X-ray data are registered using landmarks. Bone structures are used to register each MRI slice using\r\nan articulated model, and the soft tissue is confined to the volume delimited by the trunk and bone surfaces using a\r\nconstrained thin-plate spline.\r\nResults: The method is tested on 3 pre-surgical patients with scoliosis and shows a significant improvement,\r\nqualitatively and using the Dice similarity coefficient, in fitting the MRI into the standing patient model when\r\ncompared to rigid and articulated model registration. The determinant of the Jacobian of the registration deformation\r\nshows higher variations in the deformation in areas closer to the surface of the torso.\r\nConclusions: The novel, resulting 3D full torso model can provide a more complete representation of patient\r\ngeometry to be incorporated in surgical simulators under development that aim at predicting the effect of scoliosis\r\nsurgery on the external appearance of the patient�s torso....
Background: Radiofrequency ablation (RFA) is one of the most promising non-surgical treatments for hepatic\r\ntumors. The assessment of the therapeutic efficacy of RFA is usually obtained by visual comparison of pre- and\r\npost-treatment CT images, but no numerical quantification is performed.\r\nMethods: In this work, a novel method aiming at providing a more objective tool for the evaluation of RFA\r\ncoverage is described. Image registration and segmentation techniques were applied to enable the visualization of\r\nthe tumor and the corresponding post-RFA necrosis in the same framework. In addition, a set of numerical indexes\r\ndescribing tumor/necrosis overlap and their mutual position were computed.\r\nResults: After validation of segmentation step, the method was applied on a dataset composed by 10 tumors,\r\nsuspected not to be completed treated. Numerical indexes showed that only two tumors were totally treated and\r\nthe percentage of a residual tumor was in the range of 5.12%-35.92%.\r\nConclusions: This work represents a first attempt to obtain a quantitative tool aimed to assess the accuracy of RFA\r\ntreatment. The possibility to visualize the tumor and the correspondent post-RFA necrosis in the same framework\r\nand the definition of some synthetic numerical indexes could help clinicians in ameliorating RFA treatment....
Background: Cardiac involvement in sarcoidosis is associated with a poor prognosis. In patients with right sided\r\nheart failure, differentiating between cor-pulmonale, or cardiac sarcoidosis has important implications to\r\nmanagement.\r\nCase presentation: We present the case of a patient with severe but stable pulmonary sarcoidosis and new onset\r\nright sided heart failure despite only mild elevations of pulmonary artery pressure. CMR demonstration of extensive\r\nright ventricular fibrosis with associated dilatation and hypokinesis was a key finding for prognosis and\r\nmanagement of the patient.\r\nConclusion: Cardiac magnetic resonance (CMR) is the preferred investigation in the diagnosis of cardiac sarcoidosis,\r\nallowing assessment of myocardial inflammation and fibrosis, as well as function, in a manner not matched by\r\nother technologies....
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