Introduction
Extranodal disease
Modality | Advantages | Technical limitations | Diagnostic limitations | Reported sensitivity/specificity for staging Hodgkin lymphoma |
---|---|---|---|---|
Whole-body MRIa | - No ionizing radiation exposure - High spatial resolution - Excellent soft-tissue contrast - Advanced techniques (e.g., diffusion-weighted imaging) for better tissue characterization - Whole-body imaging | - Long examination time (young children often need sedation/anaesthesia) - No standard imaging protocols (e.g., variation in the included body areas or sequences used) - Motion artefacts (respirational/cardiac) - No criteria available for use in response assessment | - Involvement of nodal disease still based on size criteria - Difficult to distinguish malignant and benign disease on diffusion-weighted imaging (e.g., lymph nodes) | 91%/99% |
CT | - Widely available - Fast - Whole-body imaging | - Exposure to ionizing radiation - Inability to differentiate between active disease and residual mass - Use of intravenous contrast agents | - Involvement of nodal disease based on size criteria | 87.5%/85.6% |
FDG-PET | - High diagnostic accuracy - Detection of metabolic activity - Whole-body imaging | - Exposure to ionizing radiation - Low spatial resolution, unable to detect small lesions - Extensive patient preparation time - Long examination time | - Both malignant and infectious disease are FDG-avid | FDG-PET/CT: 100%/90.7% FDG-PET/MRI: 85.7%/100% |
Ultrasound | - No exposure to ionizing radiation - Noninvasive - Fast - Patient friendly - Widely available | - Chance of not depicting the whole organ - Not suitable for whole-body imaging | - Diffuse disease is hard to detect - Inter-observer variation | N/A |
Whole-body MRI | CT | FDG-PET | Ultrasound | |
---|---|---|---|---|
Bone marrow | - Focal hypointensity on T1-weighted images and hyperintensity on T2-weighted images compared to muscle - Restricted diffusion on diffusion-weighted imaging | - N/A | - More than 2 PET positive lesions in skeleton (irrespective of positivity in CT or MRI) - FDG uptake bone marrow should be above FDG uptake in liver | - N/A |
Bone | - Lytic/sclerotic appearance of the cortical bone | |||
Liver | - Hyperintense focus (less hyperintense than liquor) discrete from lymph node mass on T2-weighted image - Restricted diffusion on diffusion-weighted imaging | - Hypoattenuating nodules | - Focal PET positive lesions (confirmed by CT, MRI or US) | - One or more solid hypoechoic masses |
Pleura | - Nodal lesion in pleura or chest wall - With or without pleural effusiona | - Pleural plaques or nodules | - PET positive pleural nodules | - N/A |
Lung | - At least one intrapulmonary nodule >1 cm, not attached to lymph node mass - Or more than two nodules >2 mm and <10 mm within the lungs - Restricted diffusion on diffusion-weighted imaging | - Mass or mass-like consolidation - Parenchymal nodules - Peribronchial thickening - Alveolar/interstitial infiltrates | - PET positive nodules/masses | - N/A |
Spleen | - Discrete nodules - With or without enlargement - No restricted diffusion on diffusion-weighted imaging | - Hypoattenuating nodules | - Focal PET positive lesions | - One or more focal hypoechoic abnormalities (irrespective of PET result) |
E-lesion | - Disease infiltration per continuum from a lymph node mass into extralymphatic structures or organs |