MRI - Childhood Lymphona
Development of MRI for whole-body assessment of disease as an alternative to conventional methods utilizing ionising radiation.
Overview:
Lymphoma is staged using the Ann Arbor classification which relies upon a combination of clinical symptoms and accurate assessment of extent of lymph node involvement. Conventional staging procedures include biopsies, radiography, computed tomography (CT) and ultrasound. CT has been the gold standard of staging lymphoma but provides only structural information. Although CT has excellent spatial resolution, disease is only assessed based on size criteria, with lymph nodes less than 1 cm considered as not involved. Positron Emission Tomography (PET) using 18FDG adds information on the metabolic activity of the involved nodes and has increasingly been incorporated into the staging investigations in lymphoma patients. This functional information can also be particularly useful in determining response to therapy. Both CT and PET use ionising radiation and it is known that exposure to even small doses of ionising radiation is associated with a risk of development of second cancers. With disease having to be restaged at several intervals during a treatment regimen a substantial cumulative dose of radiation can be imparted to the patient as a result of the imaging investigations. The effect of this radiation exposure is of greater concern in the setting of childhood lymphoma where the relatively longer lifespan of a child allows more time for a consequential development of malignancy to manifest. Imaging techniques that allow accurate staging of disease whilst reducing exposure to ionising radiation would be of great benefit in this population. Magnetic resonance imaging with its ability to provide both accurate anatomical images and a variety of functional imaging contrasts using non-ionising radiation has the potential to perform the role of the ‘ideal’ imaging modality.
This study will compare anatomical and functional information obtained using MRI with that obtained with the current standard conventional imaging techniques of PET and CT in children and adolescents with lymphoma. MRI will be performed in addition to the routine PET and CT investigations at initial staging and restaging following chemotherapy. The ability of MRI to monitor and assess patient response to chemotherapy will be determined.
Primary Study Aims:
- Compare whole body MRI to anatomical CT and functional PET imaging in childhood lymphoma preceding chemotherapy treatment.
- Correlate functional MR imaging at time of diagnosis (diffusion, perfusion and oxygenation dependent contrast images) with PET/CT data of active tumour tissue.
- Investigate whether functional MRI changes during chemotherapy treatment can predict ultimate clinical response after a full course of treatment.
Secondary Study Aims:
- Compare MRI, CT and PET/CT characteristics of imaging classified abnormal lymph nodes with histology obtained by routine diagnostic biopsy.
- Investigate the change in imaging findings during treatment for different histologically classified disease types.