Comparison of the diagnostic accuracy of whole-body MRI and whole-body CT in stage III/IV malignant melanoma.

BACKGROUND: Malignant melanoma (MM) is dramatically increasing in light-skinned populations worldwide. Staging and regular follow-up examinations are essential. The purpose of this study was to compare the diagnostic accuracy of whole-body MRI with the standard diagnostic algorithm (whole-body CT and brain MRI) in patients with stage III/IV MM. PATIENTS AND METHODS: A group of 50 consecutively admitted patients with stage III/IV MM were included in the study. Whole-body CT and brain MRI scans were performed. Additionally, all patients underwent a whole-body MRI (1.5 Tesla Magnetom Avanto, Siemens Healthcare Sector, Erlangen). The findings were compared on a lesion-by-lesion basis as part of clinical routine follow-up. RESULTS: 33 patients received a follow-up CT and were evaluated. Overall, 824 lesions were detected. The sensitivity of whole-body MRI was observer-dependent. MRI was slightly less sensitive than CT according to the findings of the two most experienced observers (73.4 % vs. 78.2 %, p = 0.0744). CT was significantly more sensitive in the detection of small (1-5 mm) pulmonary nodules (2.9 % vs. 66.9 %, p < 0.0001). Yet overall, MRI was significantly more specific than CT (83.4 % vs. 50.4 %, p < 0.0001). CONCLUSIONS: Whole-body MRI in compliance with standard requirements for the observers (high level of experience) should be considered as an appropriate alternative to CT without ionizing radiation, particularly for young patients with advanced MM.

Can the radiation dose to CT-enlarged but FDG-PET-negative inguinal lymph nodes in anal cancer be reduced?

PURPOSE: To investigate whether a dose reduction to CT-enlarged but FDG-PET-negative (([(18)F]-fluoro-2-deoxy-D-glucose positron emission tomography) inguinal lymph nodes in radiochemotherapy of anal cancer is safe. PATIENTS AND METHODS: 39 sequential patients with anal cancer (mean age 59 years [range: 37-86 years], median follow-up 26 months [range: 3-51 months]) receiving pretherapeutic FDG-PET were included. All patients were treated with combined radiochemotherapy including elective radiation of the inguinal lymph nodes with 36 Gy. In case of involvement (FDG-PET positivity defined as normalized SUV [standard uptake value] above Delta > 2.5 higher than blood pool), radiation dose was increased up to 50-54 Gy. Planning CT and PET results were compared for detectability and localization of lymph nodes. In addition, local control and freedom from metastases were analyzed regarding the lymph node status as determined by FDG-PET. RESULTS: In the planning CTs, a total of 162 inguinal lymph nodes were detected with 16 in nine patients being suspicious. Only three of these lymph nodes in three patients were PET-positive receiving 50.4-54 Gy, whereas all other patients only received elective inguinal nodal irradiation. No recurrence in inguinal lymph nodes occurred, especially not in patients with CT-enlarged inguinal lymph nodes and elective irradiation only. Patients with PET-positive nodal disease had a higher risk of developing distant metastases (p = 0.045). CONCLUSION: Reduction of the irradiation dose to CT-enlarged but PET-negative inguinal lymph nodes in anal cancer seems not to result in increased failure rates.

Comparison of whole-body MR imaging and conventional X-ray examination in patients with multiple myeloma and implications for therapy.

Skeletal X-ray survey is the established method of diagnosis in patients with multiple myeloma; however, whole-body magnetic resonance imaging (wb-MRI) has become an important additional tool. The aim of this study was to compare the different patterns of infiltration on conventional X-ray examinations (X-ray survey) with findings from wb-MRI to subsequently determine the influence of wb-MRI on therapy changes. In 60 patients with a mean age of 65.1 +/- 11.7 years, wb-MRI examinations were correlated with a recent X-ray survey. The results were independently assessed by two radiologists and the patterns of infiltration were described in both modalities. Subsequently, the disease was staged according to Salmon and Durie and Salmon and Durie PLUS. Additionally, the influence of MRI on potential changes in therapy was assessed using a three-range Likert-type scale. In all, 480 skeletal regions were compared. In 183 skeletal regions, an increased degree of infiltration was identified on wb-MRI. Significant differences (p < 0.05) between the modalities could be found in the thorax, spine, pelvis, and both lower extremities. Based on wb-MRI, tumor stage was upgraded in 19 of the 60 patients using the Durie and Salmon PLUS classification. In ten out of these 19 patients (42%), the wb-MRI result was essential for making the decision to initiate further therapy due to the degree of infiltration, extramedullary tumor extension, and/or further risk of fracture. Whole-body MRI provides a more detailed assessment of the pattern of bone marrow infiltration and strongly influences therapeutic strategies.