An obvious example demonstrating these differences is shown in Fig. Observer 1 tended to take the shortest path from the margin of the RV septal surface to the epicardial surface whereas Observer 2 tended to follow the contour of the endocardial surface of the RV.
In the example shown in Fig. It is likely that a detailed protocol would attenuate these differences. Clot in the LV cavity a3i was excluded by Observer 1 but not by Observer 2. Images from one heart showing differences in Virtual dissection by observer 1 a and Observer 2 b and physical dissection c. Images were chosen to illustrate points made in the text rather than to represent average differences.
Selections made by Observer 1 are labelled a 1, a 2 etc. Selections made by Observer 2 are labelled b 1, b 2 etc. Photographs of the physically dissected heart are shown in the right panel labelled c. Panel a1 shows the region selected as being the left ventricle LV by Observer 1 blue shaded area and Panel b1 shows the region selected as being the LV by Observer 2 green shaded area.
The area selected as being LV by Observer 1 panel a 2 was greater than the area selected as LV by Observer 2 panel b 2. Panels a 3 and b 3 show the three-dimensional structure of the heart with the unselected surfaces in brown and the selected areas in blue Observer1, a 3 or green Observer 2, b 3.
Observer 1 and 2 show close agreement in removal of supra ventricular structures. The surface attributed to right ventricular free wall by Observer 1 is less than the surface attributed to right ventricular free wall by Observer 2.
Photographs of cut surface of LV and base of heart c 1 , cut surface of LV and apex of heart c 2 and the LV with cut surfaces apposed and the right ventricle removed exposing the septal surface of the RV c 3. Imprecision in physical dissection is apparent in the ragged edges where the RV free wall was removed. The errors that arise from inaccuracy in Physical Dissection per se Fig. Scatter plot comparing repeated measurements of mass of a dissected left ventricle on an analytical balance.
The line of equality solid line and the plotted regression equation dashed line are virtually superimposed. Difference between independent measurements on an analytical balance of LV tissue mass from a single physical dissection of the LV.
Note this analytical error is likely a small part of the error associated with dissection of the heart for direct measurement of LV mass. We have demonstrated that Virtual Dissection of X-ray micro-CT scans of iodine stained mouse hearts to determine LV size can replace physical dissection and weighing.
Micro-CT is one of a number of new tomographic techniques that have revolutionised the study of embryogenesis by permitting the viewing and analysis of complex 3-dimensional structures that previously been studied by analysis of serial 2-dimensional histological sections 14 , 15 , Virtual dissection of micro-CT, 3-dimensional images provides non-destructive measurement of left-ventricular tissue volume allowing both secondary uses and repeated measurements neither of which are possible with physical dissection.
This non-destructive method lends itself to the assessment of repeatability that is not possible with physical dissection, provides a permanent record of the three-dimensional relationship of cardiac structures that others have used to identify cardiac defects 14 , 15 and permits the use of cardiac tissue for other purposes.
The micro-CT scanning protocol with iodine staining used here offers a simple, quick and inexpensive method to phenotype cardiovascular and other soft tissue structures in laboratory mice. Micro-CT has previously been widely used to study birth defects 2 , 16 , 19 where its ability to provide a three-dimensional representation at very high resolution is unrivalled. Micro-CT can resolve structures that are much too small to be checked by physical dissection and weighing Measuring LV mass is the traditional method of assessing left ventricular hypertrophy in large animals but it poses some problems when applied to very small mouse hearts.
Removal of great vessels, atria and free wall of the right ventricle is time-consuming and difficult to complete accurately because of the small size of the organs. Thus, Ghanem et al. Quantification of these errors is difficult as the method is destructive and cannot be repeated on the same heart.
The limits of determination of volume by micro-CT is readily quantified 20 and the repeatability in practical applications can be measured. Micro-CT scanning compares very well with existing methods for determining LV mass. Only a study by Dawson et al. Farber et al. Moreover, our qualitative analysis suggests reproducibility could be improved by developing a more detailed protocol.
Better repeatability and accuracy might also be achieved by using fully automated methods, for example by the implementation of Deep Learning for LV segmentation In the best of the in vivo animal studies Dawson et al. As an alternative to weighing, Ghanem et al. Micro CT scanning is conceptually similar to this approach of serial sections with computerised 3D reconstruction.
Micro-CT scan has several advantages over histomorphometry, considered the reference standard for analysis of cardiac development 17 , including being non-destructive to tissue, having short image acquisition time and high resolution.
However, micro-CT scan has limitations such as radiation and need for use of a contrast agent to visualise soft tissues. Iodine enhances contrast by diffusion through tissue layers and binding to glycogen within muscle cells 25 , 26 and increasing X-ray absorption.
High resolution CT can provide information content comparable to that of conventional histological sectioning and staining 19 with the additional benefit of providing 3-dimensional information.
In conclusion, results obtained through the micro-CT scan and iodine staining provided high-quality morphological information at the micrometre scale. The ability to study fixed tissue that is more easily transported than live animals allows collaboration more easily with colleagues at distant locations to study unique collections of mice.
The clear advantages of micro-CT scan images over histology include a less tedious sample preparation protocol, and less time-consuming without the need for sectioning samples which could impose risks of tissue destruction and artefacts. Moreover, data obtained by the micro-CT scan enables 3D visualisation of slices in multiple imaging planes. We have confirmed that analysis of micro-CT scan data can provide accurate measurements of cardiac chamber mass.
This enables investigators to use an efficient and reliable method to assess cardiac structures of larger quantity in a shorter time period without destruction of tissues. Tissue collection was performed after euthanasia under isoflurane anaesthesia. Formalin-fixed hearts were then immersed in ethanol in order to remove formalin from heart tissue.
Following this stage, hearts were submerged in the 1. Stained hearts then were imaged at 72 h. Samples were washed in absolute ethanol and then placed on the CT scanner. The tissue specimen is placed on a stationary loading dock of the scanner, positioning it between the rotating system of X-ray source and detector.
The scanning time was pre-set at 3 min with the field of view FOV 10 mm in diameter, and the chosen mode of fine quality. The semi-automated edge-based segmentation technique 29 was used in Drishti Paint, a function of Drishti, in order to separate the LV from the rest of the heart. Using Drishti Paint, left ventricular boundaries were manually delineated in 10—15 CT scan slices.
Afterwards, Drishti Paint would collate the tagged slices and in-between slices to create a segregated left ventricle from the whole heart. The result was manually adjusted to ensure accurate definition of the cardiac contours. To standardise LV volume measurement between samples, multiple parameters were followed to minimise inter-sample measurement errors. The left ventricle was defined from the aortic ring at the base to the left ventricular apex. Interventricular septum and mitral valve papillary muscles were also included as part of the LV volume.
The right ventricular RV free wall was excluded. Virtual Dissection was performed independently by two observers. LV mass was calculated from the product of ventricular muscle volume calculated by Drishti and specific gravity of heart muscle, estimated from the average of the directly measured weights and the average of the estimated volumes of all left ventricles.
The LV was dissected from the rest of the mouse cardiac structure under magnification and the mass of the dissected LV was measured using a high-performance analytical balance, Shimadzu AUWD paying careful attention to the operating environment as described in the manual. Three sets of measurements were made on different days and the median value was used for comparison. Conceptually, there are two sources of error in Physical Left Ventricular Dissection. The larger error is likely to be the mechanical dissection of a small organ manually under a dissecting microscope.
Unfortunately, the destructive nature of this approach renders impossible the assessment of repeatability. The smaller error is likely to be the measurement error which was assessed by comparing the first two of three determinations of mass. The principal methods employed were those described by Bland and Altman to quantify agreement between two methods of measurement 30 , Prior exploratory analysis included graphing the data in scatter plots and regression analysis Differences between paired values were plotted against their mean.
The mean difference indicates the presence or absence of bias between the 2 measurements. When it appeared possible that either the mean difference or variability of the differences increased as the magnitude of the measurement increased we elected to plot the percentage difference 30 against the mean of the 2 measurements rather than log transforming the values, as initially recommended 31 , because we believed that percentages were more likely to be intuitively comprehended by the reader than logarithms and their antilogarithms.
Moreover, expressing the level of agreement as a percentage permits comparison with assessments made in larger hearts, for example, human hearts. Data and material used for this manuscript are stored in our research office and are available on request.
Hoang, K. LV mass as a predictor of CVD events in older adults with and without metabolic syndrome and diabetes. Imaging 8 , — Article Google Scholar. Lieb, W. The natural history of left ventricular geometry in the community: clinical correlates and prognostic significance of change in LV geometric pattern.
Imaging 7 , — Tsao, C. Left ventricular structure and risk of cardiovascular events: a framingham heart study cardiac magnetic resonance study. Heart Assoc. Celebi, A. Current cardiac imaging techniques for detection of left ventricular mass. Ultrasound 8 , 19 Katz, J. Part 1 provides an accessible introduction to reproducible research, a basic reproducible research project template, and a synthesis of lessons learned from across the thirty-one case studies. Parts 2 and 3 focus on the case studies themselves.
The Practice of Reproducible Research is an invaluable resource for students and researchers who wish to better understand the practice of data-intensive sciences and learn how to make their own research more reproducible. Stark, and Philip B. Books Journals. Disciplines Sciences Physical Science. Roessler PP, et al. Anatomic dissection of the anterolateral ligament ALL in paired fresh-frozen cadaveric knee joints.
Arch Orthop Trauma Surg. Correlation of magnetic resonance imaging with knee anterolateral ligament anatomy: a cadaveric study. Radiographic landmarks for locating the femoral origin and tibial insertion of the knee anterolateral ligament.
Study of the anterolateral ligament of the knee in formalin-embedded cadavers. Acta Ortop Bras. Parker M, Smith HF. Anatomical variation in the anterolateral ligament of the knee and a new dissection technique for embalmed cadaveric specimens. Anat Sci Int. The anterolateral ligament of the knee: an inconsistent finding in pediatric cadaveric specimens. J Pediatr Orthop. The anterolateral ligament in a Japanese population: study on prevalence and morphology.
J Orthop Sci. Sabzevari S, et al. Anatomic and histological investigation of the anterolateral capsular complex in the fetal knee. Download references. You can also search for this author in PubMed Google Scholar. All authors read and approved the final manuscript. Correspondence to Diego Ariel de Lima. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Reprints and Permissions. Ariel de Lima, D. Anterolateral ligament of the knee: a step-by-step dissection. BMC Musculoskelet Disord 20, Download citation. Received : 29 May Accepted : 18 March Published : 04 April Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article.
Provided by the Springer Nature SharedIt content-sharing initiative. Skip to main content. Search all BMC articles Search. Download PDF. Abstract Background The number of studies and clinical interest in the anterolateral ligament of the knee ALL has grown in recent years. Methods Twenty knees from frozen adult cadavers, with no preference for sex or age, were included in the study.
Background Since the studies conducted by Vicent et al [ 1 ], Claes et al [ 2 ]. Full size image. All the cadavers were dissected using the same technique in order to determine ALL incidence.
Results Additional file 1: Video S1 The initial dissection consisted of ample exposure of the iliotibial band ITB after the skin and subcutaneous cell tissue were removed from the anterolateral surface of the knee. Lateral collateral ligament isolation. Discussion Clinical and anatomic studies on the ALL have increased significantly in recent years.
References 1. Article Google Scholar 2. Article Google Scholar 3. Article Google Scholar 4. Article Google Scholar 5. Article Google Scholar 6. Article Google Scholar 7. Article Google Scholar 8. Article Google Scholar 9. Article Google Scholar
0コメント