Receiver operating characteristic curve analysis of SUV_max, serum TK, LD, and CRP in 34 patients with DLBCL or FL.

<p>The area under the ROC curve (AUC) was 0.796, 0.763, 0.787, or 0.787 for the SUV_max, serum TK, LD, or CRP; respectively. When the SUV_max≥10.5 was used as a cut-off value to differentiate DLBCL from FL, yielded sensitivity 87% and specificity 55%. When a TK cut-off value of ≥10.5 (U/l) or a LD cut-off value of ≥200.5 (U/l) was used to differentiate DLBCL from FL, yielded sensitivity 83% and specificity 64% to detect a DLBCL. When a CRP cut-off value of ≥1.85 (mg/l) was used to differentiate DLBCL from FL, yielded sensitivity 87% and specificity 64% to detect a DLBCL.</p

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

<p>The ADC_mean correlated inversely the MTV_wb (r = −0.43, p<0.05) (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084999#pone-0084999-g005" target="_blank">Figure 5a</a>), and it also correlated inversely with the MTB_wb (r = −0.35, p<0.05) (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084999#pone-0084999-g005" target="_blank">Figure 5b</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

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

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 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