http://www.biomedcentral.com/bmcmedimaging/ The most accessed research articles published by BMC Medical Imaging 2009-11-19T00:00:00Z This is an RSS newsfeed from BioMed Central It is intended to be used with an RSS reader. For more information about RSS newsfeeds from BioMed Central, visit http://www.biomedcentral.com/info/about/rss/ Background: Magnetic resonance cholangiopancreatography (MRCP) is an alternative to diagnostic endoscopic retrograde cholangiopancreatography (ERCP) for investigating biliary obstruction. The use of MRCP, a non-invasive procedure, may prevent the use of unnecessary invasive procedures. The aim of the study was to compare the findings of MRCP with those of ERCP by the computation of accuracy statistics. Methods: Thirteen electronic bibliographic databases, covering biomedical, science, health economics and grey literature were searched. A systematic review of studies comparing MRCP to diagnostic ERCP in patients with suspected biliary obstruction was conducted. Sensitivity, specificity, likelihood ratios, acceptability and adverse events were reported. Results: 25 studies were identified reporting several conditions including choledocholithiasis (18 studies), malignancy (four studies), obstruction (three studies), stricture (two studies) and dilatation (five studies). Three of the 18 studies reporting choledocholithiasis were excluded from the analysis due to lack of data, or differences in study design. The sensitivity for the 15 studies of choledocholithiasis ranged from 0.50 to 1.00 while specificity ranged from 0.83 to 1.00. The positive likelihood ratio ranged: from 5.44–47.72 and the negative likelihood ratio for the 15 studies ranged from 0.00–0.51. Significant heterogeneity was found across the 15 studies so the sensitivities and specificities were summarised by a Receiver Operating Characteristic (ROC) curve. For malignancy, sensitivity ranged from 0.81 to 0.94 and specificity from 0.92 to 1.00. Positive likelihood ratios ranged from 10.12 to 43 and negative likelihood ratios ranged from 0.15 to 0.21, although these estimates were less reliable. Conclusion: MRCP is a comparable diagnostic investigation in comparison to ERCP for diagnosing biliary obstruction. http://www.biomedcentral.com/1471-2342/6/9 Eva Kaltenthaler Stephen Walters Jim Chilcott Anthony Blakeborough Yolanda Bravo Vergel Steven Thomas BMC Medical Imaging 2006, 6:9 2006-08-14T00:00:00Z doi:10.1186/1471-2342-6-9 BMC Medical Imaging 1471-2342 6 9 2006-08-14T00:00:00Z XML Background: Transient ischemic attack (TIA) patients are at high vascular risk. We assessed the value of extracranial (ECD) and transcranial (TCD) Doppler and duplex ultrasonography to predict clinical outcome after TIA. Methods: 176 consecutive TIA patients admitted to the Stroke Unit were recruited in the study. All patients received diffusion-weighted imaging, standardized ECD and TCD. At a median follow-up of 27 months, new vascular events were recorded. Results: 22 (13.8%) patients experienced an ischemic stroke or TIA, 5 (3.1%) a myocardial infarction or acute coronary syndrome, and 5 (3.1%) underwent arterial revascularization. ECD revealed extracranial ≥ 50% stenosis or occlusions in 34 (19.3%) patients, TCD showed intracranial stenosis in 15 (9.2%) and collateral flow patterns due to extracranial stenosis in 5 (3.1%) cases. Multivariate analysis identified these abnormal ECD and TCD findings as predictors of new cerebral ischemic events (ECD: hazard ratio (HR) 4.30, 95% confidence interval (CI) 1.75 to 10.57, P = 0.01; TCD: HR 4.73, 95% CI 1.86 to 12.04, P = 0.01). Abnormal TCD findings were also predictive of cardiovascular ischemic events (HR 18.51, 95% CI 3.49 to 98.24, P = 0.001). Conclusion: TIA patients with abnormal TCD findings are at high risk to develop further cerebral and cardiovascular ischemic events. http://www.biomedcentral.com/1471-2342/9/13 Katrin Holzer Suwad Sadikovic Lorena Esposito Angelina Bockelbrink Dirk Sander Bernhard Hemmer Holger Poppert BMC Medical Imaging 2009, 9:13 2009-07-30T00:00:00Z doi:10.1186/1471-2342-9-13 BMC Medical Imaging 1471-2342 9 13 2009-07-30T00:00:00Z XML Background: Normal aging involves a decline in cognitive function that has been shown to correlate with volumetric change in the hippocampus, and with genetic variability in the APOE-gene. In the present study we utilize 3D MR imaging, genetic analysis and assessment of verbal memory function to investigate relationships between these factors in a sample of 170 healthy volunteers (age range 46–77 years). Methods: Brain morphometric analysis was performed with the automated segmentation work-flow implemented in FreeSurfer. Genetic analysis of the APOE genotype was determined with polymerase chain reaction (PCR) on DNA from whole-blood. All individuals were subjected to extensive neuropsychological testing, including the California Verbal Learning Test-II (CVLT). To obtain robust and easily interpretable relationships between explanatory variables and verbal memory function we applied the recent method of conditional inference trees in addition to scatterplot matrices and simple pairwise linear least-squares regression analysis. Results: APOE genotype had no significant impact on the CVLT results (scores on long delay free recall, CVLT-LD) or the ICV-normalized hippocampal volumes. Hippocampal volumes were found to decrease with age and a right-larger-than-left hippocampal asymmetry was also found. These findings are in accordance with previous studies. CVLT-LD score was shown to correlate with hippocampal volume. Multivariate conditional inference analysis showed that gender and left hippocampal volume largely dominated predictive values for CVLT-LD scores in our sample. Left hippocampal volume dominated predictive values for females but not for males. APOE genotype did not alter the model significantly, and age was only partly influencing the results. Conclusion: Gender and left hippocampal volumes are main predictors for verbal memory function in normal aging. APOE genotype did not affect the results in any part of our analysis. http://www.biomedcentral.com/1471-2342/9/17 Martin Ystad Astri Lundervold Eike Wehling Thomas Espeseth Helge Rootwelt Lars Tjelta Westlye Martin Andersson Steinunn Adolfsdottir Jonn Terje Geitung Anders Fjell Ivar Reinvang Arvid Lundervold BMC Medical Imaging 2009, 9:17 2009-08-22T00:00:00Z doi:10.1186/1471-2342-9-17 BMC Medical Imaging 1471-2342 9 17 2009-08-22T00:00:00Z XML Background: Computed Tomography (CT) has become a widely used supplement to medico legal autopsies at several forensic institutes. Amongst other things, it has proven to be very valuable in visualising fractures of the cranium. Also CT scan data are being used to create head models for biomechanical trauma analysis by Finite Element Analysis. If CT scan data are to be used for creating individual head models for retrograde trauma analysis in the future we need to ascertain how well cranial fractures are captured by CT scan. The purpose of this study was to compare the diagnostic agreement between CT and autopsy regarding cranial fractures and especially the precision with which cranial fractures are recorded. Methods: The autopsy fracture diagnosis was compared to the diagnosis of two CT readings (reconstructed with Multiplanar and Maximum Intensity Projection reconstructions) by registering the fractures on schematic drawings. The extent of the fractures was quantified by merging 3-dimensional datasets from both the autopsy as input by 3D digitizer tracing and CT scan. Results: The results showed a good diagnostic agreement regarding fractures localised in the posterior fossa, while the fracture diagnosis in the medial and anterior fossa was difficult at the first CT scan reading. The fracture diagnosis improved during the second CT scan reading. Thus using two different CT reconstructions improved diagnosis in the medial fossa and at the impact points in the cranial vault. However, fracture diagnosis in the anterior and medial fossa and of hairline fractures in general still remained difficult. Conclusion: The study showed that the forensically important fracture systems to a large extent were diagnosed on CT images using Multiplanar and Maximum Intensity Projection reconstructions. Difficulties remained in the minute diagnosis of hairline fractures. These inconsistencies need to be resolved in order to use CT scan data of victims for individual head modelling and trauma analysis. http://www.biomedcentral.com/1471-2342/9/18 Christina Jacobsen Birthe Bech Niels Lynnerup BMC Medical Imaging 2009, 9:18 2009-10-16T00:00:00Z doi:10.1186/1471-2342-9-18 BMC Medical Imaging 1471-2342 9 18 2009-10-16T00:00:00Z XML Background: An important aspect in functional imaging research employing magnetic resonance imaging (MRI) is how participants perceive the MRI scanning itself. For instance, the knowledge of how (un)comfortable MRI scanning is perceived may help institutional review boards (IRBs) or ethics committees to decide on the approval of a study, or researchers to design their experiments. Methods: We provide empirical data from our lab gained from 70 neurologically healthy mainly student subjects and from 22 mainly elderly patients suffering from motor deficits after brain damage. All participants took part in various basic research fMRI studies using a 3T MRI scanner. Directly after the scanning, all participants completed a questionnaire assessing their experience with the fMRI procedure. Results: 87.2% of the healthy subjects and 77.3% of the patients rated the MRI procedure as acceptable to comfortable. In healthy subjects, males found the procedure more comfortable, while the opposite was true for patients. 12.1% of healthy subjects considered scanning durations between 30 and 60 min as too long, while no patient considered their 30 min scanning interval as too long. 93.4% of the healthy subjects would like to participate in an fMRI study again, with a significantly lower rate for the subjects who considered the scanning as too long. Further factors, such as inclusion of a diffusion tensor imaging (DTI) scan, age, and study duration had no effect on the questionnaire responses. Of the few negative comments, the main issues were noise, the restriction to keep still for the whole time, and occasional feelings of dizziness. Conclusion: MRI scanning in the basic research setting is an acceptable procedure for elderly and patient participants as well as young healthy subjects. http://www.biomedcentral.com/1471-2342/9/14 Andre Szameitat Shan Shen Annette Sterr BMC Medical Imaging 2009, 9:14 2009-07-31T00:00:00Z doi:10.1186/1471-2342-9-14 BMC Medical Imaging 1471-2342 9 14 2009-07-31T00:00:00Z XML Background: The work presented here investigates parallel imaging applied to T1-weighted high resolution imaging for use in longitudinal volumetric clinical studies involving Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI) patients. This was in an effort to shorten acquisition times to minimise the risk of motion artefacts caused by patient discomfort and disorientation. The principle question is, "Can parallel imaging be used to acquire images at 1.5 T of sufficient quality to allow volumetric analysis of patient brains?" Methods: Optimisation studies were performed on a young healthy volunteer and the selected protocol (including the use of two different parallel imaging acceleration factors) was then tested on a cohort of 15 elderly volunteers including MCI and AD patients. In addition to automatic brain segmentation, hippocampus volumes were manually outlined and measured in all patients. The 15 patients were scanned on a second occasion approximately one week later using the same protocol and evaluated in the same manner to test repeatability of measurement using images acquired with the GRAPPA parallel imaging technique applied to the MPRAGE sequence. Results: Intraclass correlation tests show that almost perfect agreement between repeated measurements of both segmented brain parenchyma fraction and regional measurement of hippocampi. The protocol is suitable for both global and regional volumetric measurement dementia patients. Conclusion: In summary, these results indicate that parallel imaging can be used without detrimental effect to brain tissue segmentation and volumetric measurement and should be considered for both clinical and research studies where longitudinal measurements of brain tissue volumes are of interest. http://www.biomedcentral.com/1471-2342/9/15 Terri Lindholm Lisa Botes Eva-Lena Engman Anders Frank Tomas Jonsson Leif Svensson Per Julin BMC Medical Imaging 2009, 9:15 2009-08-03T00:00:00Z doi:10.1186/1471-2342-9-15 BMC Medical Imaging 1471-2342 9 15 2009-08-03T00:00:00Z XML ObjectiveTo study the effect of fasting on the technical success of abdominal ultrasound examination. Methods: In a randomized, prospective study, 150 patients for abdominal ultrasound were divided into two groups of 75 patients each with instructions to fast for six hours or have normal breakfast respectively.ResultThe technical success of the abdominal ultrasound performed by radiologists blinded to the instruction did not differ significantly between the groups. Conclusion: It appears that routine fasting before abdominal ultrasound is not necessary. http://www.biomedcentral.com/1471-2342/3/1 Tariq Sinan Hans Leven Mehraj Sheikh BMC Medical Imaging 2003, 3:1 2003-07-22T00:00:00Z doi:10.1186/1471-2342-3-1 BMC Medical Imaging 1471-2342 3 1 2003-07-22T00:00:00Z XML Background: Confocal microscopy has become an important option for examining tissues in vivo as a diagnostic tool and a quality control tool for tissue-engineered constructs. Collagen is one of the primary determinants of biomechanical stability. Since collagen is also the primary scattering element in skin and other soft tissues, we hypothesized that laser-optical imaging methods, particularly confocal scattered-light scanning, would allow us to quantify scattering intensity and determine collagen content in biological layers. Methods: We built a fully automated confocal scattered-light scanner to examine how light scatters in Intralipid, a common tissue phantom, and three-dimensional collagen gels. Intralipid with 0.5%, 1.0%, 1.5%, and 2.0% concentration was filled between precisely spaced glass coverslips. Collagen gels at collagen concentrations from 0.30mg/mL to 3.30mg/mL were prepared, and all samples underwent A-mode scanning with multiple averaged scans. In Intralipid samples, light reflected from the upper fluid-glass interface was measured. In collagen gels, average scattering intensity inside the actual gel was measured. In both cases, intensity was correlated with concentration. Results: By measuring light attenuation at interface reflections of various thicknesses using our device, we were able to determine that the scattering coefficient at 660nm of Intralipid at increasing concentrations in water to be 39 cm-1 for each percent increase of Intralipid. We were also able to measure the amount of scattering of various concentrations of collagen in gels directly using backscattered light. The results show a highly linear relationship with an increase of 8.2 arbitrary units in backscattering intensity for every 1mg increase of collagen within a 1mL gel volume. Conclusion: The confocal scattered-light scanner allows to accurately quantify scattering in Intralipid and collagen gels. Furthermore, a linear relationship between collagen concentration and intensity was found. Confocal scattered-light scanning therefore promises to allow imaging of collagen content in soft tissue layers. http://www.biomedcentral.com/1471-2342/9/19 Jeffrey LaCroix Mark Haidekker BMC Medical Imaging 2009, 9:19 2009-11-19T00:00:00Z doi:10.1186/1471-2342-9-19 BMC Medical Imaging 1471-2342 9 19 2009-11-19T00:00:00Z PDF Background: Abdominal tuberculosis (TB) is endemic in the developing world and is reemerging in the West. Since computed tomography (CT) has the ability to demonstrate changes in the peritonium, mesentry, lymphnodes, bowel and solid organs and is being increasingly used for primary evaluation of abdominal conditions, it is important to be familiar with the CT features of the disease. Methods: CT findings were retrospectively analysed in 49 patients with proved abdominal TB. Patients with genitourinary TB and with AIDS/HIV were not included in the study. Results: Peritoneal involvement was the most common feature (77.5%) with ascites (wet peritonitis) seen in more than half the cases (55.2%). The rest showed peritoneal, mesenteric or omental thickening or mass formation but no ascites (dry peritonitis). Other findings included lymphadenopathy (46.9% mainly of diffuse nature, bowel wall thickening (38%) and solid organ involvement (20.4%). Conclusions: CT reliably demonstrates the entire range of findings which need interpretation in the light of clinical and laboratory data. http://www.biomedcentral.com/1471-2342/2/3 Tariq Sinan Mehraj Sheikh Salwa Ramadan Sukhpal Sahwney Abdullah Behbehani BMC Medical Imaging 2002, 2:3 2002-11-12T00:00:00Z doi:10.1186/1471-2342-2-3 BMC Medical Imaging 1471-2342 2 3 2002-11-12T00:00:00Z XML Background: It is of great clinical importance to exclude myocardial infarction in patients with suspected coronary artery disease who do not have stress-induced ischemia. The diagnostic use of myocardial perfusion single-photon emission computed tomography (SPECT) in this situation is sometimes complicated by attenuation artifacts that mimic myocardial infarction. Imaging in the prone position has been suggested as a method to overcome this problem. Methods: In this study, 52 patients without known prior infarction and no stress-induced ischemia on SPECT imaging were examined in both supine and prone position. The results were compared with cardiac magnetic resonance imaging (CMR) with delayed-enhancement technique to confirm or exclude myocardial infarction. Results: There were 63 defects in supine-position images, 37 of which disappeared in the prone position. None of the 37 defects were associated with myocardial infarction by CMR, indicating that all of them represented attenuation artifacts. Of the remaining 26 defects that did not disappear on prone imaging, myocardial infarction was confirmed by CMR in 2; the remaining 24 had no sign of ischemic infarction but 2 had other kinds of myocardial injuries. In 3 patients, SPECT failed to detect small scars identified by CMR. Conclusion: Perfusion defects in the supine position that disappeared in the prone position were caused by attenuation, not myocardial infarction. Hence, imaging in the prone position can help to rule out ischemic heart disease for some patients admitted for SPECT with suspected but not documented ischemic heart disease. This would indicate a better prognosis and prevent unnecessary further investigations and treatment. http://www.biomedcentral.com/1471-2342/9/16 Bo Heden Eva Persson Marcus Carlsson Olle Pahlm Hakan Arheden BMC Medical Imaging 2009, 9:16 2009-08-10T00:00:00Z doi:10.1186/1471-2342-9-16 BMC Medical Imaging 1471-2342 9 16 2009-08-10T00:00:00Z XML