title: Determination of the left ventricular long-axis orientation from a single short-axis MR image: relation to BMI and age.
abstract: Accurate determination of imaging planes in relation to the left ventricular (LV) long-axis orientation is important for anatomical and functional evaluation as well as for serial comparisons with cardiac magnetic resonance (CMR) imaging. Therefore, a fast and reliable method to test the accuracy of CMR imaging for measuring the orientation of the LV long-axis was developed and validated. In addition, the relationship between LV long-axis orientation and body mass index (BMI), gender and age was assessed. Two approaches were used, a long-axis approach (based on a manually defined vector) and a short-axis approach (based on a calculated vector). The concordance between the two approaches was assessed in 72 healthy volunteers. The accuracy and precision of MR imaging for measuring three-dimensional orientations were tested using a LV phantom. The mean difference between the long- and short-axis approaches for measuring the LV long-axis orientation in the study population was 0 +/- 3 degrees, 0 +/- 2 degrees, and -1 +/- 3 degrees in the frontal, transverse and sagittal plane, respectively. BMI and age were shown to influence LV long-axis orientation, especially in the frontal and sagittal planes. A significant difference in LV long-axis orientation in the frontal and sagittal planes was found between genders. The correlation coefficient between MR-measured phantom orientation and true phantom orientation was >0.98 in all three orthogonal planes. These observations suggest that a single LV short-axis MR image can be used for measuring LV long-axis orientation in patients with no cardiac disease.
authors.affiliation: Department of Clinical Physiology, Lund University Hospital, S-221 85 Lund, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Engblom
authors.forename: Erik
authors.initials: E
authors.lastname: Hedström
authors.forename: John
authors.initials: J
authors.lastname: Palmer
authors.forename: Galen S
authors.initials: GS
authors.lastname: Wagner
authors.forename: Håkan
authors.initials: H
authors.lastname: Arheden
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000886:Anthropometry / Q000379:methods*; D015992:Body Mass Index; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D013223:Statistics as Topic; D016276:Ventricular Function