Non-Hodgkin lymphoma response evaluation with MRI texture classification

<p>Abstract</p> <p>Background</p> <p>To show magnetic resonance imaging (MRI) texture appearance change in non-Hodgkin lymphoma (NHL) during treatment with response controlled by quantitative volume analysis.</p> <p>Methods</p> <p>A total of 19 patients having NHL with an evaluable lymphoma lesion were scanned at three imaging timepoints with 1.5T device during clinical treatment evaluation. Texture characteristics of images were analyzed and classified with MaZda application and statistical tests.</p> <p>Results</p> <p>NHL tissue MRI texture imaged before treatment and under chemotherapy was classified within several subgroups, showing best discrimination with 96% correct classification in non-linear discriminant analysis of T2-weighted images.</p> <p>Texture parameters of MRI data were successfully tested with statistical tests to assess the impact of the separability of the parameters in evaluating chemotherapy response in lymphoma tissue.</p> <p>Conclusion</p> <p>Texture characteristics of MRI data were classified successfully; this proved texture analysis to be potential quantitative means of representing lymphoma tissue changes during chemotherapy response monitoring.</p

Correlations between Functional Imaging Markers Derived from PET/CT and Diffusion-Weighted MRI in Diffuse Large B-Cell Lymphoma and Follicular Lymphoma

Objectives To 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 Methods Thirty-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. Results The 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. Conclusions The 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.Public Library of Science open acces

Scatter plots showing the correlations between the SUV_max and ADC_min, (a), and between the SUV_sum and ADC_mean (b) in 34 patients with DLBCL or FL.

<p>The SUV_max correlated inversely with the ADC_min (r = −0.35, p<0.05) (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084999#pone-0084999-g003" target="_blank">Figure 3a</a>), and the SUV_sum correlated inversely with the ADC_mean (r = −0.42, p<0.05) (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084999#pone-0084999-g003" target="_blank">Figure 3b</a>) in all cases.</p

Comparison of PET/CT and DWI indexes and serum biomarkers in the DLBCL and FL groups.

<p>Comparison between the DLBCL and FL groups.</p

Demographic characteristics, tumor pathology, and clinical staging of 34 patients with DLBCL or FL.

<p>IPI (International Prognostic Index) was used for the evaluation of DLBCL. IPI 1: low risk; IPI 2: low-intermediate risk; IPI 3: high-intermediate risk; IPI 4: high risk. * FLIPI (Follicular Lymphoma International Prognostic Index) was used for FL. FLIPI 0–1: low risk; FLIPI 2: intermediate risk; FLIPI≥3: high risk.</p

Correlations (Spearman's rho) between clinical stage, IPI, or functional imaging markers and serum markers in 34 patients with DLBCL or FL.

<p>p<0.05 and</p><p>p<0.01.</p

Diffusion-weighted MRI and PET/CT images showing the abdominal region tumor in a 76- year old male patient with diffuse large B-cell lymphoma.

<p>(a) B0 image. (b) Diffusion-weighted image with b value 800 s/mm² showed the hyperintensity tumor, but it was not able to depict diffuse spleen involvement. (c) The corresponding ADC map showed the hypointensity tumor with ADC_min 0.34×10⁻³ mm²/s and ADC_mean 0.68×10⁻³ mm²/s. (d) Axial CT image. (e) FDG-PET image. (f) The fused PET/CT image showed the active tumor and spleen involvement with SUV_max 23.9.</p

Scatter plots showing the correlations between the ADC_min and the MTV_wb or MTB_wb in 34 patients with DLBCL or FL.

<p>The ADC_min correlated inversely with the MTV_wb (r = −0.54, p<0.01) (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084999#pone-0084999-g004" target="_blank">Figure 4a</a>), and it also correlated inversely with the MTB_wb (r = −0.47, p<0.01) (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084999#pone-0084999-g004" target="_blank">Figure 4b</a>) in all cases.</p

Early interim PET/CT predicts post-treatment response in diffuse large B-cell lymphoma

<div><p></p><p><b>Background.</b>¹⁸F-FDG-PET/CT has been widely used in the staging of malignant lymphomas, and accepted as a tool for response assessment. Among PET parameters, the most frequently studied is maximal standardized uptake value (SUVmax). Metabolic tumor burden (MTB) is a parameter in which both metabolic tumor volume (MTV) and tumor activity are integrated. Here, we analyzed the prognostic value of SUVmax, SUVsum (sum of the SUVmax), whole-body MTV (MTVwb) and MTBwb from baseline and interim PET/CT in patients with diffuse large B-cell lymphoma (DLBCL).</p><p><b>Material and methods.</b> Twenty-nine patients with histologically proven DLBCL were imaged by PET/CT before treatment (Exam I), and one week after the first dose of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) therapy (Exam II). Biopsy specimens were examined by an expert hematopathologist, the Ki-67 proliferation index (PI) was estimated for each biopsy site from the MIB-1 stained sections. The response evaluation was performed after chemotherapy completion (6–8 cycles).</p><p><b>Results</b>. All patients had one or more visualized lymphomatous lesions on ¹⁸F-FDG-PET/CT. The SUVmax of the whole-body (BmSUVmax) was higher than the SUVmax at biopsy site (BxSUVmax) (mean: 20.1 vs. 17.3, p < 0.01). The PI correlated with the BxSUVmax (p < 0.05). One week after chemotherapy, SUVmax, SUVsum, MTVwb, and MTBwb decreased significantly (p < 0.01, respectively), SUVsum, MTVwb and MTBwb at Exam II correlated with chemotherapy response at treatment completion (p < 0.05, respectively).</p><p><b>Conclusion</b>. 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.</p></div