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At least 793 records · Page 44Linked to original sources
PubMed1990

The effect of accuracy constraints on three-dimensional movement kinematics.

The kinematics of three-dimensional arm movements were recorded during a task in which subjects were required to place a peg in a hole. The accuracy constraint was varied by using holes of different diameters. If the diameter of the hole was large relative to the diameter of the peg, the tangential velocity profile of hand trajectories was relatively symmetric and bell-shaped, but it became increasingly asymmetric as the diameter of the hole was reduced. Peak tangential velocity decreased, overall movement duration increased and the proportion of the movement spent in deceleration increased systematically. The shape of the accelerative phase of the velocity profile showed little dependence on hole diameter, but the decelerative phase became increasingly irregular as the hole diameter was reduced. This irregularity was attributed to submovements corresponding to small changes in the direction of the hand path. On the other hand, deliberately slowing the movement in the absence of a strict accuracy constraint induced a change in the velocity profile which produced irregularity in both the accelerative and decelerative phases of the movement. The results of our experiments are consistent with the idea that movements requiring extreme accuracy and other slow movements are composed of a series of submovements. In the case of movements requiring accuracy these submovements may represent corrective actions that are taken throughout the course of the movement.

Adult↗
PubMed1989

The effect of patient-to-patient variability on the accuracy of predictive assays of tumor response to radiotherapy: a theoretical evaluation.

Mathematical modeling was used to investigate the relative accuracy that might be expected from predictive assays of tumor response to radiotherapy based on one of the following four tumor characteristics: intrinsic tumor-cell radiosensitivity, doubling time of the clonogenic tumor cells, number of clonogens in the tumor at the start of treatment, and extent of hypoxia in the tumor. In particular, the influence of inter-tumor heterogeneity on predictive accuracy was investigated. Wide patient-to-patient variability in a tumor characteristic contributing to treatment response adds to the accuracy of a predictive assay based on that characteristic, but variability from patient to patient in factors influencing response, but not measured by the assay, has a confounding effect and reduces predictive accuracy. The results of this theoretical study suggest that predictive assays based on intrinsic tumor-cell radiosensitivity are much more likely to be correlated with clinical outcome than are assays based on clonogen doubling time, hypoxic fraction, or clonogen number, since individual differences in tumor radiosensitivity can seriously confound assays based on the other factors. It is concluded that it may be necessary to correct for individual differences in intrinsic radiosensitivity before predictive assays based on other tumor characteristics, such as potential doubling time, might have any detectable clinical significance.

Colony-Forming Units Assay↗
PubMedDate not supplied

The relative accuracy and reliability of histological aging methods.

Histological aging methods of Kerley and of Ahlqvist and Damsten were applied to bone samples from thirteen individuals of known age at death. Relative accuracy and reliability were determined for six of Kerley's predicting formulas for the femur, fibula and tibia, and his profile method, Ahlqvist and Damsten's femoral predicting formulas, and age determined by averaging ages predicted by Kerley's six formulas. Averaging age estimates by Kerley's six formulas (mean regression) was found to produce the overall greatest accuracy and reliability. Dividing the sample into two age groups (13 - 51 and 60 - 102 years) altered the results only slightly. Kerley's femoral intact osteon formula produced the greatest accuracy for individuals in the younger age category, while his fibular osteon fragment formula was most accurate for older ages. Mean regression produced the greatest reliability for all age classes. Based upon both accuracy and reliability, averaging age predictions by Kerley's regression formulas appears to be the method of choice for broad application of histological aging.

Adolescent↗
PubMed1996

Accuracy of biplane and multiplane transesophageal echocardiography in diagnosis of typical acute aortic dissection and intramural hematoma.

OBJECTIVES: The purpose of this study was to evaluate the diagnostic accuracy of biplane and multiplane transesophageal echocardiography in patients with suspected aortic dissection, including intramural hematoma. BACKGROUND: Transesophageal echocardiography is a useful technique for rapid bedside evaluation of patients with suspected acute aortic dissection. The sensitivity of transesophageal echocardiography is high, but the diagnostic accuracy of biplane and multiplane transesophageal echocardiography for dissection and intramural hematoma is less well defined. METHODS: We studied 112 consecutive patients at a major referral center who had undergone biplane or multiplane transesophageal echocardiography to identify aortic dissection. The presence, absence and type of aortic dissection (type A or B, typical dissection or intramural hematoma) were confirmed by operation or autopsy in 60 patients and by other imaging techniques in all. The accuracy of transesophageal echocardiography for ancillary findings of aortic dissection (intimal flap, fenestration and thrombosis) was assessed in the 60 patients with available surgical data. RESULTS: Of the 112 patients, aortic dissection was present in 49 (44%); 10 of these had intramural hematoma (5 with and 5 without involvement of the ascending aorta). Of the remaining 63 patients without dissection, 33 (29%) had aortic aneurysm and 30 (27%) had neither dissection nor aneurysm. The overall sensitivity and specificity of transesophageal echocardiography for the presence of dissection were 98% and 95%, respectively. The specificity for type A and type B dissection was 97% and 99%, respectively. The sensitivity and specificity for intramural hematoma was 90% and 99%, respectively. The accuracy of transesophageal echocardiography for diagnosis of acute significant aortic regurgitation and pericardial tamponade was 100%. CONCLUSIONS: Biplane and multiplane transesophageal echocardiography are highly accurate for prospective identification of the presence and site of aortic dissection, its ancillary findings and major complications in a large series of patients with varied aortic pathology. Intramural hematoma carries a high complication rate and should be treated identically with aortic dissection.

Acute Disease↗
PubMed1994

Diagnostic accuracy of predicting coronary artery disease related to patients' characteristics.

Patients' demographic and clinical characteristics may affect diagnostic accuracy of cardiologists. We asked a group of experienced cardiologists from three institutions to estimate the pretest probability of coronary artery disease in 257 patients referred for diagnostic coronary angiography and with no history of previous myocardial infarction nor valvular heart disease. Physicians pretest estimates were compared with the diagnostic findings of coronary angiography. We tested the influence of five variables on the accuracy of the pretest estimates: age, sex, chest pain characteristics, rest electrocardiogram and electrocardiographic exercise test result. Cardiologists tended to overestimate the presence of coronary artery disease and this tendency was particularly remarkable in the group of patients showing a negative exercise test. Pretest diagnostic accuracy was 0.72 when the test result was negative and 0.85 when the test result was positive (95% confidence interval of the difference 0.03 to 0.23; p < 0.001). The diagnosis of coronary artery disease was also more accurate for male than for female patients (0.81 vs 0.70; 95% confidence interval of the difference 0.02 to 0.21; p < 0.02). Characteristics of chest pain, age and rest electrocardiogram did not affect the level of pretest diagnostic accuracy. Cardiologists should be cognizant of correctly interpreting a negative exercise test and the clinical data of female patients; in both cases, they should move circumspect of the diagnosis of coronary artery disease.

Age Factors↗
PubMed1994

Relative accuracy and reproducibility of regional MRI brain volumes for point-counting methods.

Volumetric magnetic resonance imaging (MRI) methods for the measurement of various neuroanatomical regions are of great interest in studies of neuropsychiatric disorders. Both manual and semiautomated methods have been developed. Manual methods include tracing and point counting. Point counting methods are widely used in post-mortem and microscopy studies. Point counting has been well validated for these purposes. In this article, we report in a series of separate studies the accuracy and reproducibility of point-counting methods. Absolute accuracy was evaluated with a spherical phantom. Accuracy and time efficiency were subsequently assessed with an anatomically realistic phantom and various size grids. The point-counting method was also compared to a tracing method. Finally, the reproducibility of the point-counting method for the caudate and putamen was evaluated on four subjects in a test-retest experiment. These studies provide an estimate of the accuracy and time efficiency of point-counting methods. The test-retest reliability was also high for both caudate and putamen. Findings suggest that point counting is a reliable and efficient method for estimating volumes.

Brain↗
PubMed2005

Accuracy of computed tomography attenuation values in the characterization of pleural fluid: an ROC study.

RATIONALE AND OBJECTIVES: To assess the accuracy of computed tomography (CT) in characterizing pleural fluid based on attenuation values. MATERIALS AND METHODS: Protocol was approved by the local institutional review board and informed consent was waived. We retrospectively analyzed 145 pleural effusions of 145 patients (mean/standard deviation age: 60.7/15.9 years; 69 females) who underwent CT of the thorax and diagnostic thoracentesis within 7 days of each other. Effusions were classified as transudates or exudates using laboratory markers based on Light's criteria. The mean Hounsfield units (HU) of an effusion was determined by a region of interest on the three slices with the greatest anteroposterior diameter. A receiver operating characteristic curve was constructed to determine threshold values for classification on the basis of mean HU and to examine overall accuracy, using the area under the curve (A(z)). RESULTS: Of the 101 exudates and 44 transudates, the mean attenuation of exudates (17.1 HU/standard deviation 4.4) was significantly higher than transudates (12.5 HU/6.3), (P < .001). There was a modest but significant positive relationship between mean HU and laboratory markers, with the strongest relationship with pleural/serum protein (r = 0.57, P < .001) and total pleural protein (r = 0.56, P < .001). The overall accuracy of attenuation values for identifying exudates was moderate, Az = 0.775, standard error = 0.039, with the largest limitation being the overlap with transudates in the 10-20 HU range, which constituted 66% (90/145) of the total effusions measured. CONCLUSION: Although the mean attenuation of exudates is significantly higher than transudates, the clinical use of CT numbers to characterize pleural fluid is not recommended, as their accuracy is only moderate. Moreover, there is a notable overlap in attenuation values between transudates and exudates for a majority of effusions.

Adolescent↗
PubMed2006

Interrater reliability in assessing quality of diagnostic accuracy studies using the QUADAS tool. A preliminary assessment.

RATIONALE AND OBJECTIVES: Quality Assessment of Diagnostic Accuracy Studies (QUADAS) is a new tool to measure the methodological quality of diagnostic accuracy studies in systematic reviews. We used data from a systematic review of magnetic resonance spectroscopy (MRS) in the characterization of suspected brain tumors to provide a preliminary evaluation of the inter-rater reliability of QUADAS. MATERIALS AND METHODS: A structured literature search identified 19 diagnostic accuracy studies. These publications were distributed randomly to primary and secondary reviewers for dual independent assessment. Reviewers recorded methodological quality by using QUADAS on a custom-designed spreadsheet. We calculated correlation, percentage of agreement, and kappa statistic to assess inter-rater reliability. RESULTS: Most studies in our review were judged to have used an accurate reference standard. Conversely, the MRS literature frequently failed to specify the length of time between index and reference tests or that the clinicians were unaware of the index test findings when reporting the reference standard. There was good correlation (rho = 0.78) between reviewers in assessment of the overall number of quality criteria met. However, mean agreement for individual QUADAS questions was only fair (kappa = 0.22) and ranged from no agreement beyond chance (kappa < 0) to moderate agreement (kappa = 0.58). CONCLUSION: Inter-rater reliability in our study was relatively low. Nevertheless, we believe that QUADAS potentially is a useful tool for highlighting the strengths and weaknesses of existing diagnostic accuracy studies. Low reliability suggests that different reviewers will reach different conclusions if QUADAS is used to exclude "low-quality" articles from meta-analyses. We discuss methods for improving the validity and reliability of QUADAS.

Brain Neoplasms↗
PubMed2006

Documentation and coding of ED patient encounters: an evaluation of the accuracy of an electronic medical record.

OBJECTIVE: The aim of the study was to describe a paper-based, template-driven and an electronic medical record used for capturing emergency care clinical information and to compare the accuracy of these documentation systems for coding patient encounters using the American Medical Association Current Procedural Terminology-2004 (AMA CPT-2004) evaluation and management codes intended for provider reimbursement. METHODS: A retrospective, cross-sectional study of 4-consecutive-day samples of ED patient encounter records from 2 similar community hospitals was done. For clinical documentation, hospital A uses an electronic medical record, whereas hospital B uses a paper-based template-driven record. Using a simple analytic model, expert coders A and B, respectively, coded the records from hospitals A and B for completeness. First, power analysis determined the acceptability of the patient record sample sizes (1 - beta = .90 at 1% significance level), and the frequency of AMA CPT-2004 primary evaluation and management codes 99281 through 99285 was calculated. Second, the completeness discrepancy rates for hospitals A and B were compared to determine the accuracy of both the paper-based, template-driven record and the electronic medical record in documenting and representing the clinical encounter. Third, interrater reliability between expert coders A and B was calculated to assess the level of agreement between each expert coder in determining the completeness discrepancy rates between hospitals A and B. Finally, the frequency of primary evaluation and management codes was analyzed to determine if there was a statistically significant difference between the paper-based, template-driven record and the electronic medical record representation of the clinical information, and if that difference could be attributable to the differing clinical documentation systems used in hospitals A and B. RESULTS: First, descriptive display demonstrated a difference in the frequency of the primary evaluation and management codes 99283 and 99284 within hospital A (expert coder A assessment, 36.1% vs 39.1%; expert coder B assessment, 36.6% vs 38.7%) and hospital B (expert coder A assessment, 47.8% vs 21.9%; expert coder B assessment, 48.6% vs 21.4%) was noted with the median, primary evaluation, and management code for hospital A of 99284 and the median, primary evaluation, and management code for hospital B of 99283. Second, Fisher exact test compared the completeness discrepancy rates between hospitals A and B as assessed by each expert coder and demonstrated no statistically significant difference in the completeness discrepancy rates (accuracy) between the paper-based, template-driven record and the electronic medical record documentation and coding system when assessed by either expert coder A (P = .370) or expert coder B (P = .819). Third, interrater reliability between expert coders A and B was evaluated using Cohen's kappa statistic. When evaluated both individually and jointly with respect to hospitals A and B, expert coders A and B had a good strength of agreement in their assessments of the accuracy of the documentation and coding system for hospital A (kappa = 0.6200) and hospital B (kappa = 0.6906) as well as for both hospitals evaluated together (kappa = 0.6616). Finally, interhospital differences in the frequency of primary evaluation and management codes were evaluated using Pearson chi(2) test with 3 df. The results for expert coder A (chi(2) = 47.4160; P < .001) and expert coder B (chi(2) = 46.5946; P < .001) recognize that there is a statistically significant degree of difference between hospitals A and B in the frequency distribution of primary evaluation and management codes, probably because of the dispersion of codes 99283 and 99284. CONCLUSIONS: A keystroke-driven, electronic medical record that resides on a knowledge platform that incorporates a clinical structured terminology, administrative coding schemata, AMA CPT-2004 codes and uses object-oriented, open-ended, branching chain clinical algorithms that "force" physician documentation of the clinical elements provides an equally accurate capture and representation of ED clinical encounter data as a paper-based, template-driven documentation system both in terms of the presence or absence of both the medically necessary, discrete data elements and the textual documentation-dependent, medical decision-making elements.

Chi-Square Distribution↗
PubMed2006

The diagnostic accuracy of 64-slice computed tomography coronary angiography compared with stress nuclear imaging in emergency department low-risk chest pain patients.

STUDY OBJECTIVE: We compared the accuracy of multidetector computed tomography (CT) coronary angiography with stress nuclear imaging for the detection of an acute coronary syndrome or 30-day major adverse cardiac events in low-risk chest pain patients. METHODS: This was a prospective study of the diagnostic accuracy of myocardial perfusion imaging and multidetector CT in low-risk chest pain patients. The target condition was an acute coronary syndrome (confirmed >70% coronary stenosis on coronary artery catheterization) or major adverse cardiac events within 30 days. Patients were low risk by Reilly/Goldman criteria and had negative serial ECGs and cardiac markers. All had both rest/stress sestamibi nuclear imaging and multidetector CT. Patients with abnormal stress nuclear imaging results (reversible perfusion defects) or multidetector CT results (stenosis >50% or calcium score >400) were considered for cardiac catheterization, and those with discordant results had a greater than 30-day reevaluation (including ECG) by a cardiologist. All were followed up for evidence of major adverse cardiac events within 30 days by review of hospital records and structured telephone interview. Primary outcomes were the accuracy of multidetector CT and myocardial perfusion imaging for the detection of an acute coronary syndrome and 30-day major adverse cardiac events. RESULTS: Of the 92 patients, 7 (8%) were excluded because of uninterpretable multidetector CT scans. Of the remaining 85 study patients (49+/-11 years, 53% men), 7 (8%) were found to have the target condition, with all having significant coronary stenosis (88%+/-9%) and none having myocardial infarction or major adverse cardiac events during 30 days. Stress nuclear imaging results were negative in 72 (85%) patients, and multidetector CT results were negative in 73 (86%) patients. The sensitivity of stress nuclear imaging was 71% (95% confidence interval [CI] 36% to 92%), and multidetector CT was 86% (95% CI 49% to 97%), and the specificity was 90% (95% CI 81% to 95%) and 92% (95% CI 84% to 96%), respectively. The negative predictive value of stress nuclear imaging and multidetector CT was 97% (95% CI 90% to 99%) and 99% (95% CI 93% to 100%), respectively, and the positive predictive value was 38% (95% CI 18% to 64%) and 50% (95% CI 25% to 75%), respectively. CONCLUSION: The accuracy of multidetector CT is at least as good as that of stress nuclear imaging for the detection and exclusion of an acute coronary syndrome in low-risk chest pain patients.

Adult↗
PubMed2004

Recency affects reporting accuracy of children's dietary recalls.

PURPOSE: This study evaluated the effect of recency on accuracy of fourth-graders' dietary reports. METHODS: Each of 60 randomly selected children was observed eating school meals (breakfast, lunch) and interviewed to obtain a 24-hour dietary recall using one of six conditions generated by crossing two target periods (previous day, prior 24 hours) with three interview times (morning, afternoon, evening), with 10 children (5 males) per condition. Accuracy of the school meal portions of each recall was assessed by comparing reports to observations. Rates for omissions (items observed but not reported) and intrusions (items reported but not observed) were calculated to determine accuracy for reporting items. A measure of total inaccuracy combined errors for reporting items and amounts. RESULTS: Using the prior 24 hours as the target period yielded better performance than did using the previous day: Omission rates were lower by about one-third, intrusion rates by about one-half, and total inaccuracy by about one-third (all p's<0.01). A marginally significant interaction of target period by interview time was found for omission rate (p=0.08), but not for intrusion rate (p=0.15) or for total inaccuracy (p=0.47). CONCLUSIONS: This provides evidence that recency influences children's recall accuracy and demonstrates the importance of an awareness of principles of memory when designing what are essentially memory tests for epidemiologic studies.

Child↗
PubMed2006

Influence of amino acid properties for discriminating outer membrane proteins at better accuracy.

Discriminating outer membrane proteins (OMPs) from other folding types of globular and membrane proteins is an important task both for identifying outer membrane proteins from genomic sequences and for the successful prediction of their secondary and tertiary structures. In this work, we have analyzed the influence of physico-chemical, energetic and conformational properties of amino acid residues for discriminating outer membrane proteins using different machine learning algorithms, such as, Bayes rules, Logistic functions, Neural networks, Support vector machines, Decision trees, etc. We observed that most of the properties have discriminated the OMPs with similar accuracy. The neural network method with the property, free energy change could discriminate the OMPs from other folding types of globular and membrane proteins at the 5-fold cross-validation accuracy of 94.4% in a dataset of 1,088 proteins, which is better than that obtained with amino acid composition. The accuracy of discriminating globular proteins is 94.3% and that of transmembrane helical (TMH) proteins is 91.8%. Further, the neural network method is tested with globular proteins belonging to 30 major folding types and it could successfully exclude 99.4% of the considered 1612 non-redundant proteins. These accuracy levels are comparable to or better than other methods in the literature. We suggest that this method could be effectively used to discriminate OMPs and for detecting OMPs in genomic sequences.

Algorithms↗
PubMed2005

Quantification of long chain polyunsaturated fatty acids by gas chromatography. Evaluation of factors affecting accuracy.

The accurate and reproducible analysis of long-chain polyunsaturated fatty acids (PUFA) is of growing importance. Especially for labeling purposes, clear guidelines are needed in order to achieve optimum accuracy. Since calibration standards cannot be used for method validation due to the instability of PUFAs, there is no direct way to check for the absence of systematic errors. In this study the sources of error that weaken the accuracy were evaluated using theoretical considerations and calibration standards with corrected composition. It was demonstrated that the key role for optimum accuracy lies in the optimization of the split injection system. Even when following the instructions outlined in the official methods of the American Oil Chemist's Society (AOCS), systematic errors of more than 7% can arise. Clear guidelines regarding system calibration and selection of appropriate internal standards (IS) can improve precision and accuracy significantly.

Chromatography, Gas↗
PubMed2006

Diagnostic accuracy of portal-phase CT and MRI with mangafodipir trisodium in detecting liver metastases from colorectal carcinoma.

AIM: To compare the diagnostic accuracy of single section spiral computed tomography (CT) and magnetic resonance imaging (MRI) with tissue-specific contrast agent mangafodipir trisodium (MnDPDP) in the detection of colorectal liver metastases. MATERIAL AND METHODS: One hundred and twenty-five consecutive patients undergoing surgery for primary and/or metastatic disease were evaluated using CT (5 mm collimation and reconstruction interval, pitch 2), two-dimensional fast spoiled gradient echo (2D FSPGR) T1 and single shot fast-spin echo (SSFSE) T2 weighted breath-hold MRI sequences, performed before and after intravenous administration of MnDPDP. The reference standards were intraoperative ultrasound and histology. RESULTS: The per-patient accuracy of CT was 72.8 versus 78.4% for unenhanced MRI (p = 0.071) and 82.4% for MnDPDP-enhanced MRI (p = 0.005). MnDPDP-enhanced MRI appeared to be more accurate than unenhanced MRI but this was not significant (p = 0.059). The sensitivity of CT was 48.4% versus 58.1% for unenhanced MRI (p = 0.083) and 66.1% for MnDPDP-enhanced MRI (p = 0.004). The difference in specificity between procedures was not significant. The per-lesion sensitivity was 71.7, 74.9 and 82.7% for CT, unenhanced MRI, and MnDPDP-enhanced MRI, respectively; the positive predictive value of the procedures was respectively 84.0, 96.0 and 95.8%. MnDPDP-enhanced MRI provided a high level diagnostic confidence in 92.5% of the cases versus 82.5% for both unenhanced MRI and CT. The kappa value for inter-observer variability was >0.75 for all procedures. CONCLUSIONS: The diagnostic accuracy and sensitivity of MnDPDP-enhanced MRI is significantly higher than single section spiral CT in the detection of colorectal cancer liver metastases; no significant difference in diagnostic accuracy was observed between unenhanced MRI and MnDPDP-enhanced MRI.

Adult↗
PubMed2004

Accuracy of coronary artery anatomy using two-dimensional echocardiography in d-transposition of great arteries using a two-reviewer method.

We evaluated echocardiographic accuracy for defining coronary artery course in d-transposition of great arteries and the impact of a 2-reviewer method on this accuracy. The echocardiogram reports of 108 patients with d-transposition of great arteries were reviewed for coronary anatomy and compared with the operative report. In method 1, from January 1995 to December 1997, a single reader performed the echocardiogram. In method 2, from January 1998 to December 2000, 2 readers scanned individually and a consensus diagnosis was made. Comparing methods 1 and 2, the sensitivity of the echocardiogram to detect variants in coronary anatomy was 68% versus 86%, and negative predictive value was 72% versus 91%. Using a 2-reviewer method improved the accuracy of echocardiographic diagnosis of coronary anatomy with d-transposition of great arteries, aiding in risk assessment and treatment of the patient preoperatively. This study also illustrates that echocardiographic accuracy may be lower in an institution with a surgical volume more representative of the usual pediatric cardiothoracic surgical center.

Coronary Vessels↗
PubMed2006

Accuracy, reproducibility, and comparability of Doppler tissue imaging by two high-end ultrasound systems.

INTRODUCTION: Doppler tissue imaging is a new technology for quantitative evaluation of myocardial motion and contractility, and is available in several ultrasound systems. This study evaluates the comparability, accuracy, and reproducibility of measurements of velocity, strain rate, and strain by two high-end ultrasound systems. METHODS: Accuracy was assessed by imaging a tissue-mimicking gelatin phantom, and the comparability of measurements in the right ventricular free wall and interventricular septum was assessed in 20 healthy participants. Reproducibility was evaluated by repeated recordings in vitro and in a random subset of patients. RESULTS: In vitro, a high degree of accuracy was found in both systems, with one system measuring slightly lower values than the reference values (mean difference 0.35 +/- 0.18 cm/s, P < .001). Values higher than the reference values were measured by both systems for strain and strain rate. In vivo, no systematic differences in measured velocities, strain rate, and strain were found; however, wide limits of agreement were seen for strain and strain rate. Measurements of tissue velocity, strain, and strain rate were well reproducible, nevertheless wide variation was found in both systems (coefficient of variation = 9%-19%). CONCLUSION: For clinical purposes, both systems have sufficient accuracy for measurements of tissue velocity. The variation in measurements of strain rate and strain by Doppler tissue imaging should be taken into account when designing studies using this new technology. Approaches to potentially reduce this variation should be addressed in future studies.

Echocardiography, Doppler↗
PubMed2005

Accuracy of thin section magnetic resonance using phased-array pelvic coil in predicting the T-staging of rectal cancer.

Magnetic resonance (MR) imaging may contribute to staging rectal cancer and inform the decision regarding administration of pre-operative radiotherapy. The accuracy of MR has been debated. The aim of the present study was to determine the accuracy of thin section T2-weighted MR images in rectal cancer patients. MR results were compared with histological assessment of resection specimens. Over a 2-year period, 42 patients were studied. Histological staging was pT2 n = 13, pT3 n = 25 and pT4 n = 4. MR diagnostic accuracy was 74%. MR sensitivity and specificity was 62% and 79% for pT2 lesions, 84% and 59% for pT3 lesions and 50% and 76% for pT4 lesions. Estimation of tumour penetration by thin section MR imaging of rectal cancers using pelvic phased-array coil has moderate diagnostic accuracy. The limitations of MR should be acknowledged when selecting rectal cancer patients for pre-operative radiotherapy.

Adenocarcinoma↗
PubMed2005

Do technical parameters affect the diagnostic accuracy of virtual bronchoscopy in patients with suspected airways stenosis?

PURPOSE: Virtual bronchoscopy has gained popularity over the past decade as an alternative investigation to conventional bronchoscopy in the diagnosis, grading and monitoring of airway disease. The effect of technical parameters on diagnostic outcome from virtual bronchoscopy has not been determined. This meta-analysis aims to estimate accuracy of virtual compared to conventional bronchoscopy in patients with suspected airway stenosis, and evaluate the influence of technical parameters. MATERIALS AND METHODS: A MEDLINE search was used to identify relevant published studies. The primary endpoint was the "correct diagnosis" of stenotic lesions on virtual compared to conventional bronchoscopy. Secondary endpoints included the effects of the technical parameters (pitch, collimation, reconstruction interval, rendering method, and scanner type), and date of publication on the diagnostic accuracy of virtual bronchoscopy. RESULTS: Thirteen studies containing 454 patients were identified. Meta-analysis showed good overall diagnostic performance with 85% calculated pooled sensitivity (95% CI 77-91%), 87% specificity (95% CI 81-92%) and area under the curve (AUC) of 0.947. Subgroups included collimation of 3mm or more (AUC 0.948), pitch of 1 (AUC 0.955), surface rendering technique (AUC 0.935), and reconstruction interval of more than 1.25 mm (AUC 0.914). There was no significant difference in accuracy accounting for publication date, scanner type or any of the above variables. Weighted regression analysis confirmed none of these variables could significantly account for study heterogeneity. CONCLUSION: Virtual bronchoscopy performs well in the investigation of patients with suspected airway stenosis. Overall sensitivity and specificity and diagnostic odds ratio for diagnosis of airway stenosis were high. The effects of pitch, collimation, reconstruction interval, rendering technique, scanner type, and publication date on diagnostic accuracy were not significant.

Airway Obstruction↗