Current Issue : April - June Volume : 2014 Issue Number : 2 Articles : 6 Articles
Background: Correct characterization of focal solid hepatic lesions has always been a challenge and is of great\r\ndiagnostic and therapeutic relevance. The purpose of this study was to determine the added value of hepatobiliary\r\nphase images in Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) for differentiating focal solid\r\nhepatic lesions.\r\nMethods: In this retrospective trial 84 consecutive patients underwent Gd-EOB-DTPA-enhanced MR examinations.\r\nMRI was conducted for 64 patients with malignant focal hepatic lesions (34 hepatocellular carcinoma (HCC),\r\n30 metastases) and for 20 patients with benign hepatic lesions (14 focal nodular hyperplasia (FNH), 3 adenoma,\r\n3 hemangioma). Five radiologists independently reviewed three sets of MR images by means of a 5-point\r\nconfidence scale from score 1 (definitely benign) to score 5 (definitely malignant): set 1: unenhanced images; set 2:\r\nunenhanced and Gd-EOB-DTPA-enhanced dynamic images; set 3: hepatobiliary phase images in addition to set 2.\r\nAccuracy was assessed by the alternative free-response receiver operating characteristic curve (Az) and the index\r\nof diagnostic performance was calculated.\r\nResults: Diagnostic accuracy was significantly improved by the addition of Gd-EOB-DTPA-enhanced dynamic\r\nimages: Az in set 1 was 0.708 and 0.833 in set 2 (P = 0.0002). The addition of hepatobiliary phase images\r\nincreased the Az value to 0.941 in set 3 (set 3 vs set 2, P < 0.0001; set 3 vs set 1, P < 0.0001). The index of diagnostic\r\nperformance was lowest in set 1 (45%), improved in set 2 (71%), and highest in set 3 (94%).\r\nConclusions: Hepatobiliary phase images obtained after Gd-EOB-DTPA-enhanced dynamic MRI improve the\r\ndifferentiation of focal solid hepatic lesions....
Background: Diagnostic performance in breast screening programs may be influenced by the prior probability of\r\ndisease. Since breast cancer incidence is roughly half a percent in the general population there is a large probability\r\nthat the screening exam will be normal. That factor may contribute to false negatives. Screening programs typically\r\nexhibit about 83% sensitivity and 91% specificity. This investigation was undertaken to determine if a system could\r\nbe developed to pre-sort screening-images into normal and suspicious bins based on their likelihood to contain\r\ndisease. Wavelets were investigated as a method to parse the image data, potentially removing confounding\r\ninformation. The development of a classification system based on features extracted from wavelet transformed\r\nmammograms is reported.\r\nMethods: In the multi-step procedure images were processed using 2D discrete wavelet transforms to create a set\r\nof maps at different size scales. Next, statistical features were computed from each map, and a subset of these\r\nfeatures was the input for a concerted-effort set of na�¯ve Bayesian classifiers. The classifier network was constructed\r\nto calculate the probability that the parent mammography image contained an abnormality. The abnormalities\r\nwere not identified, nor were they regionalized.\r\nThe algorithm was tested on two publicly available databases: the Digital Database for Screening Mammography\r\n(DDSM) and the Mammographic Images Analysis Societyâ��s database (MIAS). These databases contain\r\nradiologist-verified images and feature common abnormalities including: spiculations, masses, geometric\r\ndeformations and fibroid tissues.\r\nResults: The classifier-network designs tested achieved sensitivities and specificities sufficient to be potentially\r\nuseful in a clinical setting. This first series of tests identified networks with 100% sensitivity and up to 79%\r\nspecificity for abnormalities. This performance significantly exceeds the mean sensitivity reported in literature\r\nfor the unaided human expert.\r\nConclusions: Classifiers based on wavelet-derived features proved to be highly sensitive to a range of pathologies,\r\nas a result Type II errors were nearly eliminated. Pre-sorting the images changed the prior probability in the\r\nsorted database from 37% to 74%....
Background: Chronic Achilles tendinosis is a common problem. When evaluating and comparing different\r\ntherapies there is a need for reliable imaging methods. Our aim was to evaluate if chronic Achilles tendinosis\r\naffects the dynamic contrast-enhancement in the tendon and its surroundings and if short-term eccentric\r\ncalf-muscle training normalizes the dynamic contrast-enhancement.\r\nMethods: 20 patients with chronic Achilles tendinopathy were included. Median duration of symptoms was\r\n31 months (range 6 to 120 months). Both Achilles tendons were examined with dynamic contrast enhanced MRI\r\nbefore and after a 12- week exercise programme of eccentric calf-muscle training. The dynamic MRI was evaluated\r\nin tendon, vessel and in fat ventrally of tendon. Area under the curve (AUC), time to peak of signal, signal increase\r\nper second (SI/s) and increase in signal between start and peak as a percentage (SI%) was calculated. Pain and\r\nperformance were evaluated using a questionnaire.\r\nResults: In the fat ventrally of the tendon, dynamic contrast enhancement was significantly higher in the\r\nsymptomatic leg compared to the contralateral non-symptomatic leg before but not after treatment. Despite\r\ndecreased pain and improved performance there was no significant change of dynamic contrast enhancement in\r\nsymptomatic tendons after treatment.\r\nConclusion: In Achilles tendinosis there is an increased contrast enhancement in the fat ventrally of the tendon.\r\nThe lack of correlation with symptoms and the lack of significant changes in tendon contrast enhancement\r\nparameters do however indicate that dynamic enhanced MRI is currently not a useful method to evaluate chronic\r\nAchilles tendinosis....
Background: Concerns have been raised regarding growth in advanced diagnostic imaging use. This study evaluated\r\ntrends in national outpatient MRI/CT utilization rates during 2000-2009 and factors associated with utilization.\r\nMethods: This retrospective database analysis used data on all respondents in the nationally representative U.S. Medical\r\nExpenditure Panel Survey (MEPS) during 2000-2009. Visits involving advanced diagnostic imaging were identified based\r\non self-reported use of MRI or CT tests at emergency departments, office-based medical providers, and outpatient\r\ndepartments. The imaging utilization rate was defined as the number of outpatient visits with MRI/CT per 1,000\r\nperson-years. Results were weighted to create nationally representative estimates at the person-year level for each year\r\nand the pooled 10-year period. A multivariate logistic regression was estimated to identify predictors of imaging use.\r\nResults: A total of 319,246 person-years were included in the analysis. MRI/CT utilization rates increased from 64.3 to\r\n109.1 per 1,000 person years from 2000 to 2009, with older persons, females and Medicare enrollees having higher rates\r\nof use. Growth in imaging slowed in recent years; the average annual decline in the imaging growth rate was larger than\r\nthat for all outpatient services (4.7% vs. 0.9%). The percentage of respondents with MRI/CT use (6.7% during 2000-2009)\r\nalso increased at a slower rate in later years and declined during 2007-2009. The average number of MRI/CT visits among\r\nimaging users was steady at about 1.5 visits during 2000-2009. Age, female gender, White race, HMO participation, and\r\nall payer types (vs. uninsured) were significant predictors of imaging use. Compared to 2005, years 2000-2003\r\nwere associated with a significantly lower likelihood of imaging use, while years 2004-2009 were not significantly\r\nassociated, suggesting a slow-down in later years.\r\nConclusions: Growth in advanced imaging utilization appears to have slowed in recent years, a finding of potential\r\ninterest to policy-makers and payers....
Background: No study relating the changes obtained in the architecture of erector spinae (ES) muscle were\r\nregistered with ultrasound and different intensities of muscle contraction recorded by surface EMG\r\n(electromyography) on the ES muscle was found. The aim of this study was analyse the relationship in the response\r\nof the ES muscle during isometric moderate and light lumbar isometric extension considering architecture and\r\nfunctional muscle variables.\r\nMethods: Cross-sectional study. 46 subjects (52% men) with a group mean age of 30.4 (Ã?±7.78). The participants\r\ndeveloped isometric lumbar extension while performing moderate and low isometric trunk and hip extension in a\r\nsitting position with hips flexed 90 degrees and the lumbar spine in neutral position. During these measurements,\r\nelectromyography recordings and ultrasound images were taken bilaterally. Bilaterally pennation angle, muscle\r\nthickness, torque and muscle activation were measured. This study was developed at the human movement\r\nanalysis laboratory of the Health Science Faculty of the University of Malaga (Spain).\r\nResults: Strong and moderate correlations were found at moderate and low intensities contraction between the\r\nvariable of the same intensity, with correlation values ranging from 0.726 (Torque Moderate ââ?¬â?? EMG Left Moderate)\r\nto 0.923 (Angle Left Light ââ?¬â?? Angle Right Light) (p < 0.001). This correlation is observed between the variables that\r\ndescribe the same intensity of contraction, showing a poor correlation between variables of different intensities.\r\nConclusion: There is a strong relationship between architecture and function variables of ES muscle when describe\r\nan isometric lumbar extension at light or moderate intensity....
Background: Sentinel node biopsy often results in the identification and removal of multiple nodes as sentinel\r\nnodes, although most of these nodes could be non-sentinel nodes. This study investigated whether computed\r\ntomography-lymphography (CT-LG) can distinguish sentinel nodes from non-sentinel nodes and whether sentinel\r\nnodes identified by CT-LG can accurately stage the axilla in patients with breast cancer.\r\nMethods: This study included 184 patients with breast cancer and clinically negative nodes. Contrast agent was\r\ninjected interstitially. The location of sentinel nodes was marked on the skin surface using a CT laser light navigator\r\nsystem. Lymph nodes located just under the marks were first removed as sentinel nodes. Then, all dyed nodes or\r\nall hot nodes were removed.\r\nResults: The mean number of sentinel nodes identified by CT-LG was significantly lower than that of dyed and/or\r\nhot nodes removed (1.1 vs 1.8, p <0.0001). Twenty-three (12.5%) patients had =2 sentinel nodes identified by CT-LG\r\nremoved, whereas 94 (51.1%) of patients had =2 dyed and/or hot nodes removed (p <0.0001). Pathological\r\nevaluation demonstrated that 47 (25.5%) of 184 patients had metastasis to at least one node. All 47 patients\r\ndemonstrated metastases to at least one of the sentinel nodes identified by CT-LG.\r\nConclusions: CT-LG can distinguish sentinel nodes from non-sentinel nodes, and sentinel nodes identified by\r\nCT-LG can accurately stage the axilla in patients with breast cancer. Successful identification of sentinel nodes using\r\nCT-LG may facilitate image-based diagnosis of metastasis, possibly leading to the omission of sentinel node biopsy....
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