To determine the feasibility of diffusion-weighted MRI (DWI) in the evaluation of the early chemotherapeutic response in patients with aggressive non-Hodgkin's lymphoma (NHL), eight patients with histologically proven diffuse large B-cell lymphoma were imaged by MRI, including DWI, and positron emission tomography/computed tomography (PET/CT) before treatment (E1), and after 1 week (E2) and two cycles (E3) of chemotherapy. In all patients, whole-body screening using T(1) - and T(2) -weighted images in the coronal plane was performed. To quantitatively evaluate the chemotherapeutic response, axial images including DWI were acquired. Apparent diffusion coefficient (ADC) maps were reconstructed, and the ADC value of the tumor was measured. In addition, the tumor volume was estimated on axial T(2) -weighted images. The maximum standardized uptake value (SUV(max) ) and active tumor volume were measured on fused PET/CT images. Lymphomas showed high signal intensity on DW images and low signal intensity on ADC maps, except for necrotic foci. The mean pre-therapy ADC was 0.71 × 10(-3) mm(2) /s; it increased by 77% at E2 (p < 0.05) and 24% more at E3 (insignificant); the total increase was 106% (p < 0.05). The mean tumor volume by MRI was 276 mL at baseline; it decreased by 58% at E2 (p < 0.05) and 65% more at E3 (p < 0.05), giving a total decrease of 84% (p < 0.05). All the imaged pre-therapy tumors were strongly positive on PET/CT, with a mean SUV(max) of 20. The SUV(max) decreased by 60% at E2 (p < 0.05) and 59% more at E3 (p < 0.05), giving a total decrease of 83% (p < 0.05). The active tumor burden decreased by 66% at E2 (p < 0.05). At baseline, both central and peripheral tumor ADC values correlated inversely with SUV(max) (p < 0.05), and also correlated inversely with active tumor burden on PET/CT and with tumor volume on MRI at E2 (p < 0.05). In conclusion, the results of DWI in combination with whole-body MRI were comparable with those of integrated PET/CT.

The combined intraoperative injection technique with radioisotope and blue dye is fast enough to identify the ovarian sentinel node(s). The stained nodes were consistently located on a certain lymphatic area. The sentinel node concept for the early ovarian cancer deserves more attention.

In patients with ovarian tumor(s), the detection of sentinel nodes is feasible. They are located in different anatomic areas both ipsilaterally and contralaterally, although most of them are found in the para-aortic region. The reliability of the sentinel node concept should be evaluated in the framework of a multicenter trial.

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ObjectivesTo investigate the correlations between functional imaging markers derived from positron emission tomography/computed tomography (PET/CT) and diffusion-weighted magnetic resonance imaging (DWI) in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). Further to compare the usefulness of these tumor markers in differentiating diagnosis of the two common types of Non-Hodgkin's lymphoma (NHL).Materials and MethodsThirty-four consecutive pre-therapy adult patients with proven NHL (23 DLBCL and 11 FL) underwent PET/CT and MRI examinations and laboratory tests. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and metabolic tumor burden (MTB) were determined from the PET/CT images. DWI was performed in addition to conventional MRI sequences using two b values (0 and 800 s/mm2). The minimum and mean apparent diffusion coefficient (ADCmin and ADCmean) were measured on the parametric ADC maps.ResultsThe SUVmax correlated inversely with the ADCmin (r = −0.35, p<0.05). The ADCmin, ADCmean, serum thymidine kinase (TK), Beta 2-microglobulin (B2m), lactate dehydrogenase (LD), and C-reactive protein (CRP) correlated with both whole-body MTV and whole-body MTB (p<0.05 or 0.01). The SUVmax, TK, LD, and CRP were significantly higher in the DLBCL group than in the FL group. Receiver operating characteristic curve analysis showed that they were reasonable predictors in differentiating DLBCL from FL.ConclusionsThe functional imaging markers determined from PET/CT and DWI are associated, and the SUVmax is superior to the ADCmin in differentiating DLBCL from FL. All the measured serum markers are associated with functional imaging markers. Serum LD, TK, and CRP are useful in differentiating DLBCL from FL.

Standardized uptake value (SUV) is a marker of tumor glucose metabolism detected by [18F]-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT). The maximum SUV of the whole-body (BmSUV(max)) reflects the tumor aggressiveness in non-Hodgkin lymphoma. To evaluate the correlation between SUV(max) at biopsy site (BxSUV(max)) and proliferation potential of tumor cells in untreated diffuse large B-cell lymphoma (DLBCL), fifteen pre-therapy PET/CT scans in patients with histologically proven DLBCL were retrospectively analyzed together with Ki-67 proliferation index. The BmSUV(max) and BxSUV(max) were evaluated from the fused PET/CT images. Ki-67 proliferation index was measured in the biopsy specimens using an immunohistochemical technique in archival paraffin-embedded sections. The BmSUV(max) was significantly higher than the BxSUV(max) (mean 19.6 vs.16.6, p < 0.01). The BxSUV(max) correlated with the Ki-67 proliferation index (r = 0.7, p < 0.01), but no correlation was detected between the BmSUV(max) and the Ki-67 proliferation index. The results indicate that tumor proliferation potential might be predicted in vivo by FDG-PET/CT images. Thus, PET/CT is useful to guide biopsy by selecting sites with the BmSUV(max) when clinically appropriate.

Standard chemotherapy causes rapid decrease of both tumor metabolic activity and volume as early as 1 week, which continues to decline during therapy. Both volumetric MRI and PET/CT are valuable tools for early treatment response evaluation of aggressive NHL.

SUVmax is more accurate to detect tumor aggressiveness than biopsy in DLBCL, since BmSUVmax represents the most aggressive tumor of the patient. Interim PET/CT as early as one week after R-CHOP therapy predicts response. Thus, it could be used as a tool for guidance of risk stratification in DLBCL.