Computerised tomography in the staging of Hodgkin's disease and non-Hodgkin's lymphoma

An uncommon clinical presentation of retroperitoneal non-Hodgkin lymphoma successfully treated with chemotherapy: A case report

We report the case of a patient affected by an extra-nodal non-Hodgkin lymphoma presenting as a unique, large retroperitoneal mass with an unusual clinical presentation mimicking gastric peptic or neoplastic disease. The patient was successfully treated with a first generation therapy, CHOP modified regimen (cyclophosphamide 600 mg/m² intravenously on d 1, epirubicin 55 mg/m² intravenously on d 1, vincristine 1.2 mg/m² intravenously on d 1, prednisone 60 mg/m² on d 1-5), and a complete response was achieved. The (18)F-fluorodeoxyglucose positron emission tomography was used to assess the therapy outcome. A brief review of literature is provided.

67Ga-SPECT/CT with a hybrid system in the clinical management of lymphoma

PURPOSE

The purpose of this study was to investigate the added value of co-registered fusion imaging using a hybrid system in patients with lymphoma.

METHODS

Twenty-four lymphoma patients underwent (67)Ga-SPECT/CT using a hybrid tomograph consisting of a dual-head, variable-angle gamma camera and a low-dose X-ray tube. Results were compared with those of SPECT alone.

RESULTS

Forty-five lesions were identified by SPECT alone, while 49 were detected by SPECT/CT. Forty out of the 45 lesions observed on SPECT were confirmed as lymphoma, but five were due to other causes (thoracic aorta blood pool activity, sialoadenitis in the submandibular gland, bowel activity, rib fracture and bone marrow activation due to radiotherapy). SPECT/CT identified nine more neoplastic lesions compared with SPECT alone: four areas of radiopharmaceutical accumulation were observed in para-aortic lymph nodes, three in the spleen, one in the liver and one in para-iliac lymph nodes. In five cases, SPECT/CT provided additional anatomical information over SPECT alone. In four patients, four large areas of (67)Ga uptake (one mediastinal, two supraclavicular and one para-aortic) were better characterised; in one subject uptake was localised in the seventh thoracic vertebra only by SPECT/CT. Hybrid imaging provided additional data in 13 patients (54.2%), thus inducing oncologists to reconsider the therapeutic approach in eight subjects (33.2%): unnecessary treatment was avoided in four (16.6%) while therapy was altered in another four (16.6%).

CONCLUSION

SPECT/CT hybrid system is able to provide information not obtained by SPECT alone. It allows the anatomical localisation of lymphoma and physiological radiopharmaceutical uptake, facilitates the diagnosis of tumours located in the abdomen (subdiaphragmatic lesions) and provides information that may cause a change in therapeutic strategy.

Clinical applications of fluorodeoxyglucose-positron emission tomography in the management of malignant melanoma

PURPOSE OF REVIEW

Malignant melanoma is the seventh most common newly diagnosed cancer among Americans. In most cases, melanoma is curable by means of surgical excision if diagnosed in early stages of the disease. The prognosis is linked directly to the initial stage at the time of diagnosis. Early diagnosis and accurate disease staging is important for appropriate treatment planning. This review focuses on clinical applications of positron emission tomography (PET) using F-fluorodeoxyglucose (FDG) in the management of patients with malignant melanoma.

RECENT FINDINGS

Many investigators have studied the role of FDG-PET in the management of malignant melanoma. PET has been shown to have a strong role in detection of metastatic disease. FDG-PET can highlight metastases at unusual sites that are easily missed with conventional imaging modalities. It is more sensitive than computed tomography (CT) for detection of metastatic lesions in skin, lymph nodes, and abdomen. Despite the overall superiority of FDG-PET in the detection of melanoma metastases, it has limitations in detection of early-stage disease (stage I-II), small lung nodules, and brain metastases. Most of the false-negative FDG-PET results are due to micrometastases and lesions small than 10 mm. False-positive FDG-PET results are due to postsurgical inflammation, other inflammatory lesions, and some benign tumors.

SUMMARY

FDG-PET is a metabolic, noninvasive imaging modality for detecting distant metastatic and recurrent melanoma. FDG-PET is of limited use in patients with early-stage disease and cannot replace sentinel node biopsy, which is much more sensitive in detecting microscopic lymph node metastases.

Fluorodeoxyglucose-PET in the management of malignant melanoma

FDG-PET is of limited use in patients with early-stage disease without nodal or distant metastases (stage I-II), because sentinel node biopsy is much more sensitive in detecting microscopic lymph node metastases. Because of the high tumor-to-background ratio, FDG-PET can highlight metastases at unusual sites that are easily missed with conventional imaging modalities. PET has been shown to have a strong role in detecting metastatic disease. FDG-PET is more sensitive than CT for detecting metastatic lesions in skin, lymph nodes, and abdomen, but CT is equivalent to or more sensitive than FDG-PET for detecting small pulmonary lesions. FDG-PET identifies the location and number of metastatic lesions in stage III and IV disease and therefore is important for surgical planning. Most of the false-negative FDG-PET results are caused by micrometastases and lesion smaller than 10 mm. Postsurgical inflammation, other inflammatory lesions, and some benign tumors cause some false-positive FDG-PET results.

Utility of fluorodeoxyglucose-PET imaging in the management of patients with Hodgkin's and non-Hodgkin's lymphomas

FDG-PET imaging has a number of advantages in the management of patients with lymphoma. PET shows a functional metabolic status and gives quantitative information. In addition, PET provides whole-body images that give a comprehensive assessment of disease extent during the staging and followup. Based on the present literature, FDG-PET is at least equivalent to CT for the initial staging of lymphomas. The impact of new technologies of combined PET/CT and fast-scanning CT with contrast has yet to be evaluated in the management of lymphoma patients, however. At this point, FDG-PET and CT must be considered as giving complementary staging information. FDG-PET also has high diagnostic accuracy for restaging lymphoma after initial treatment. FDG-PET has shown high accuracy in the early prediction of response to chemotherapy and in the evaluation of residual masses after chemotherapy or radiation therapy. Therefore, PET is likely to play a major role in tailoring the intensity of the treatment to the individual patient. A pretreatment FDG-PET study is essential for accurate assessment of residual masses and early monitoring of response to the treatment. In addition, a baseline PET scan will help detect relapse or residual disease, because relapse occurs most often in the region of previous disease.