Imaging modalities for detecting arthropathy

A Q&A with Andrea Doria (Canada)

 “Health professionals can make better use of anatomic imaging techniques that are already available in our hospitals and participate in the clinical translation of new functional imaging techniques,” says Dr. Andrea Doria, of the Department of Medical Imaging, University of Toronto and the Hospital for Sick Children (Canada). These new approaches will lead to earlier, more effective detection of changes in hemophilic joints and constitute the future state-of-the-art diagnostic techniques for assessing
hemophilic arthropathy, she says.

Q: Where does imaging fit the diagnostic picture for hemophilia?
A: “Although the diagnosis of hemophilia is mainly based on clinical and laboratory tests, imaging has an important role in confirming the diagnosis, detecting minimal changes in affected joints, and evaluating the status of the joints over the course of treatment and prophylaxis.

“At the moment, X-rays remain the most widely used diagnostic imaging tool for assessing hemophilic arthropathy, but both magnetic resonance (MRI) and ultrasound imaging provide appealing advantages in detecting early changes in hemophilic joints. With the development of standardized protocols for data acquisition and interpretation of images, these two modalities should become more widely used in day-by-day clinical practice at hemophilia clinics around the world.”

Q: What other new techniques are on the horizon?
A: “In the future, anatomic and functional imaging techniques may merge towards providing a personalized diagnostic approach to hemophilic patients. Upon completion of clinical validation, novel functional imaging techniques such as blood oxygen level-dependent MRI, ultrasmall superparamagnetic iron-oxide contrast-enhanced MRI, T1 and T2 mapping, ultrasound biomicroscopy, and positron emission tomography, among others, should be included in the imaging arsenal for diagnosis of very early abnormalities in hemophilic joints.”

Q: How can new imaging options improve hemophilia care?
A: “The use of ultrasound and MRI in clinical practice may allow the recognition of subclinical bleeds in hemophilic joints. We cannot get this information with conventional radiography or clinical examination, and it’s extremely important for management decisions in terms of prophylaxis.

“The eventual fusion of anatomic and functional imaging in clinical practice will certainly lead to tremendous improvements in the early diagnosis and treatment of hemophilic patients. However, the translation of these new techniques into clinical practice will require a long validation process. So it will be at least a decade before it’s realistic to think of them as part of the routine diagnostic arsenal for hemophilic arthropathy.”

Q: What are some of the challenges with these new modalities?
A: “MRI is very sensitive for the detection of early soft tissue and cartilage changes in hemophilic joints. Nevertheless, the gradient-echo technique that is most sensitive for the depiction of these changes has a susceptibility-weighted artifact that obscures underlying joint changes. This artifact occurs because the presence of certain blood degradation products in the joint (hemosiderin) causes ‘blooming’ that shows up as black spots. In severe cases with a large amount of hemosiderin in the joint, most of the joint is obscured by the susceptibility artifact from the MRI, making it more difficult to accurately diagnose pathology.”

Q: Are there aspects of your research that are particularly pertinent to the treatment of children with hemophilia?
A: “Many hemophilic patients start bleeding into their joints before reaching two years of age. As a pediatric radiologist, I am particularly cautious about using sedation in children under seven who undergo MRIs. Over the last few years, my research group at Sick Kids has worked in collaboration with international centres to develop, validate, and disseminate the results of non-invasive measurement tools and imaging techniques, such as ultrasound, that do not require sedation in younger hemophilic patients.”

Dr. Doria’s plenary was delivered at the XXIX International Congress of the World Federation of Hemophilia, Buenos Aires, Argentina, July 10-14, 2010. Her state of the art paper, published in a special supplement of the WFH’s official journal Haemophilia, is available here.

Last Updated September 2010