+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

Iron-oxide-enhanced magnetic resonance imaging of atherosclerotic plaques: postmortem analysis of accuracy, inter-observer agreement, and pitfalls

Iron-oxide-enhanced magnetic resonance imaging of atherosclerotic plaques: postmortem analysis of accuracy, inter-observer agreement, and pitfalls

Investigative Radiology 37(7): 405-411

INTRODUCTION: Contrast-enhanced magnetic resonance (MR) imaging using ultra small superparamagnetic iron oxide (USPIO) particles is a new noninvasive modality for imaging inflammatory atherosclerotic plaques. We determined the accuracy, interobserver agreement, and potential sources of error of this technique by means of postmortem MR imaging of aortic preparations. MATERIAL AND METHODS: Anesthetized atherosclerotic Watanabe heritable hyperlipidemic (WHHL) rabbits were studied after administration of different dosages of intravenous USPIO (DDM 43/34, IDF Berlin, Germany) and different postcontrast time intervals. A (n=5) received 0 mumol Fe/kg. B (n=5) received 50 mumol Fe/kg, 8-hour postcontrast interval. C (n=5) received 50 mumol, 24 hours. D received 200 mumol, 48 hours. The aortas were removed and 3-mm segments prepared for postmortem examination by MR imaging using a T2-weighted gradient-echo sequence (TR/TE/FA; 41 milliseconds/11 milliseconds/15degree), radiography (mammography), and histology (iron staining). USPIO accumulation was defined as the presence of 20 iron-positive cells per microscopic view (X100 magnification). Two independent readers analyzed the MR images and rated their confidence level for a positive MRI finding, defined as a focal signal loss, on a 5-point scale. The results were evaluated by receiver-operator characteristic (ROC) analysis. RESULTS: Of a total of 621 vessel segments technically acceptable for evaluation, 534 were histologically negative and 87 positive. Accuracy, expressed as the area under the ROC curve, was 0.85 for reader 1 and 0.88 for reader 2. Interobserver agreement was 0.67. False-positive findings were established by at least one reader for 121 of the 621 segments, false-negative findings for only 15 segments. Calcifications and mural thrombi were identified as potential sources of error of the method. CONCLUSION: Postmortem USPIO-enhanced MR imaging of atherosclerotic plaques showed a high accuracy and good interobserver agreement in the animal model used here. Further optimization of the method should aim at reducing the rather high percentage of false-positive results.

(PDF emailed within 1 workday: $29.90)

Accession: 010885547

Download citation: RISBibTeXText

PMID: 12068163

Related references

Magnetic resonance imaging of atherosclerotic plaques using superparamagnetic iron oxide particles. Journal of Magnetic Resonance Imaging 14(4): 355-361, 2001

Ultrasmall superparamagnetic iron oxide-enhanced magnetic resonance angiography combined with inflammatory factors for detecting atherosclerotic plaques in rabbits. Nan Fang Yi Ke Da Xue Xue Bao 34(9): 1324-1328, 2015

Accumulation of ultrasmall superparamagnetic particles of iron oxide in human atherosclerotic plaques can be detected by in vivo magnetic resonance imaging. Circulation 107(19): 2453-2458, 2003

Magnetic Resonance Imaging (MRI) of the TMJ: Influence on therapy and inter-observer agreement of two radiologists. Rofo 174(11): 1415-1421, 2002

Superparamagnetic iron oxide binding and uptake as imaged by magnetic resonance is mediated by the integrin receptor Mac-1 (CD11b/CD18): implications on imaging of atherosclerotic plaques. Atherosclerosis 193(1): 102-111, 2006

Magnetic resonance enteroclysis in the diagnosis of small-intestinal Crohn's disease: diagnostic accuracy and inter- and intra-observer agreement. Acta Radiologica 47(10): 1008-1016, 2006

Detection of small hepatocellular carcinoma: can gadoxetic acid-enhanced magnetic resonance imaging replace combining gadopentetate dimeglumine-enhanced and superparamagnetic iron oxide-enhanced magnetic resonance imaging?. Investigative Radiology 45(11): 740-746, 2011

Inter-observer agreement in the identification of the two bundles of the anterior cruciate ligament using magnetic resonance imaging. Surgical and Radiologic Anatomy 30(7): 557-562, 2008

Inter-observer agreement and diagnostic accuracy of myocardial perfusion reserve quantification by cardiovascular magnetic resonance at 3 Tesla in comparison to quantitative coronary angiography. Journal of Cardiovascular Magnetic Resonance 15: 25-25, 2013

Accuracy, intermethod agreement, and inter-reviewer agreement for use of magnetic resonance imaging and myelography in small-breed dogs with naturally occurring first-time intervertebral disk extrusion. Journal of the American Veterinary Medical Association 240(8): 969-977, 2012

Comparison of the inflammatory burden of truly asymptomatic carotid atheroma with atherosclerotic plaques contralateral to symptomatic carotid stenosis: an ultra small superparamagnetic iron oxide enhanced magnetic resonance study. Journal of Neurology, Neurosurgery, and Psychiatry 78(12): 1337-1343, 2007

Inter-Observer Agreement on Diffusion-Weighted Magnetic Resonance Imaging Interpretation for Diagnosis of Acute Ischemic Stroke Among Emergency Physicians. Turkish Journal of Emergency Medicine 15(2): 64-68, 2016

Inter- and intra-observer reproducibility of 3.0 T high-resolution magnetic resonance imaging for evaluating atherosclerotic stenosis in the middle cerebral artery. Nan Fang Yi Ke Da Xue Xue Bao 34(10): 1402-1407, 2015

Lipid-rich atherosclerotic plaques detected by gadofluorine-enhanced in vivo magnetic resonance imaging. Circulation 109(23): 2890-2896, 2004

Gadofosveset-enhanced magnetic resonance imaging of human carotid atherosclerotic plaques: a proof-of-concept study. Investigative Radiology 45(5): 275-281, 2010