Search

Hodgkin lymphomas (HL) and non-Hodgkin lymphomas (NHL) are clonal lymphoproliferative diseases that can present with different clinical manifestations that may be difficult to diagnose (Evans & Hancock, 2003; Re et al, 2005). The Ann Summary An accurate initial staging of patients with non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) is critical for the selection of an appropriate treatment. Computed tomography (CT) remains the standard imaging technique, although it is based on anatomic criteria. Positron emission tomography (PET) with 2-deoxy-2-(fluorine-18)fluoro-d-glucose (FDG) provides useful functional information but requires anatomical correlation to localise lesions accurately. We have prospectively compared the accuracy of combined PET/CT with that of CT and PET alone at initial staging in lymphoma patients. Forty-seven newly diagnosed patients were evaluated. PET/CT was superior compared with CT and PET in nodal evaluation and detection of extranodal disease. Using a staging algorithm with PET/CT resulted in the disease stage being increased in 11 of 47 patients (10 NHL and 1 HL) (McNemar test P ¼ 0AE012). Therefore, a different treatment strategy based on PET/CT findings was suggested for seven patients (14AE8%). PET/CT markedly improves accuracy in the diagnostic work-up of patients with lymphoma.

PET/CT combines functional and morphologic data and increases diagnostic accuracy in a variety of malignancies. This study prospectively compares the agreement between contrast-enhanced full-dose PET/CT and unenhanced low-dose PET/CT in lesion detection and initial staging of Hodgkin's disease and non-Hodgkin's lymphoma.Forty-seven biopsy-proven lymphoma patients underwent a 18F-FDG PET/CT study that included unenhanced low-dose CT and enhanced full-dose CT for initial staging. Patients who had undergone previous diagnostic CT for initial staging were excluded. For every patient, each modality of PET/CT images was evaluated by either of 2 pairs of readers, with each pair comprising 1 experienced radiologist and 1 experienced nuclear physician. While evaluating one of the 2 types of PET/CT, the readers were unaware of the results of the other type. Lesion detection, number of sites affected in each anatomic region, and disease stage were assessed. Agreement between techniques was determined by the kappa-statistic, and discordances were studied by the McNemar test. Clinical, analytic, histopathologic, diagnostic CT, and PET data; data from other imaging techniques; and follow-up data constituted the reference standard.For region-based analysis, no significant differences were found between unenhanced low-dose PET/CT and contrast-enhanced full-dose PET/CT, although full-dose PET/CT showed fewer indeterminate findings and a higher number of extranodal sites affected than did low-dose PET/CT. Agreement between the 2 types of PET/CT was almost perfect for disease stage (kappa = 0.92; P0.001).Our study showed a good correlation between unenhanced low-dose PET/CT and contrast-enhanced full-dose PET/CT for lymph node and extranodal disease in lymphomas, suggesting that unenhanced low-dose PET/CT might suffice in most patients as the only imaging technique for the initial staging of lymphomas, reserving diagnostic CT for selected cases.

The incidence of Hodgkin's disease (HD) and Non-Hodgkin's lymphoma (NHL) is around 8% of all malignancies. Fortunately, HD and NHL are among the few malignancies that are potentially curable with current existing treatment modalities, even in advanced or recurrent disease. Accurate staging, early therapy monitoring, and posttreatment evaluation of lymphomas are important for optimum management of these patients. We reviewed the imaging findings of patients with histologically proved lymphoma who underwent staging positron emission tomography/computed tomography (PET/CT), early monitoring therapy PET/CT (after 3 cycles of chemotherapy), and posttreatment PET/CT. PET/CT imaging findings are shown. Utility of PET/CT in recognizing false-positive and false-negative cases of CT and PET alone is addressed. Pitfalls and diagnostic difficulties are analyzed. PET/CT is a new imaging technology that improves the evaluation of lymphoma. This review will help the reader to better understand the imaging findings and applications of PET/CT in the management of lymphoma.