Early Treatment Response Evaluation in Patients with Diffuse Large B-Cell Lymphoma—A Pilot Study Comparing Volumetric MRI and PET/CT

Prognostic Significance Of Sequential 18f-fdg Pet/Ct During Frontline Treatment Of Peripheral T Cell Lymphomas

BACKGROUND/AIMS

The prognostic significance of 18F-fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography (PET/CT) in peripheral T-cell lymphomas (PTCLs) are controversial. We explored the prognostic impact of sequential 18F-FDG PET/CT during frontline chemotherapy of patients with PTCLs.

METHODS

In total, 143 patients with newly diagnosed PTCLs were included. Sequential 18F-FDG PET/CTs were performed at the time of diagnosis, during chemotherapy, and at the end of chemotherapy. The baseline total metabolic tumor volume (TMTV) was calculated using the the standard uptake value with a threshold method of 2.5.

RESULTS

A baseline TMTV of 457.0 cm3 was used to categorize patients into high and low TMTV groups. Patients with a requirehigh TMTV had shorter progression-free survival (PFS) and overall survival (OS) than those with a low TMTV (PFS, 9.8 vs. 26.5 mo, p = 0.043; OS, 18.9 vs. 71.2 mo, p = 0.004). The interim 18F-FDG PET/CT response score was recorded as 1, 2-3, and 4-5 according to the Deauville criteria. The PFS and OS showed significant differences according to the interim 18F-FDG PET/CT response score (PFS, 120.7 vs. 34.1 vs. 5.1 mo, p < 0.001; OS, not reached vs. 61.1 mo vs. 12.1 mo, p < 0.001).

CONCLUSION

The interim PET/CT response based on visual assessment predicts disease progression and survival outcome in PTCLs. A high baseline TMTV is associated with a poor response to anthracycline-based chemotherapy in PTCLs. However, TMTV was not an independent predictor for PFS in the multivariate analysis.

The Association Between Liver and Tumor [18F]FDG Uptake in Patients with Diffuse Large B Cell Lymphoma During Chemotherapy

PURPOSE

The aim of this study was to explore the association between liver, mediastinum and tumor 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) uptake during chemotherapy in diffuse large B cell lymphoma (DLBCL).

PROCEDURES

Nineteen patients with proven DLBCL underwent positron emission tomography (PET)/X-ray computed tomography scan at baseline, 1 week and 2 cycles after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) therapy, and again after chemotherapy completion. The mean and maximal standardized uptake value (SUVmean and SUVmax) of the liver and mediastinum were measured and correlated with the tumor SUVmax, SUVsum, whole-body metabolic tumor volume (MTVwb), and total lesion glycolysis (TLG).

RESULTS

At baseline, both the liver and mediastinum SUVmean and SUVmax correlated inversely with the tumor MTVwb or TLG (p < 0.01 or 0.001). The liver SUVmean and SUVmax increased significantly after 1 week of R-CHOP therapy and remained at the high level until chemotherapy completion. The mediastinum SUVmean and SUVmax remained stable during chemotherapy. The tumor SUVmax, SUVsum, MTVwb, and TLG decreased significantly after 1 week of R-CHOP therapy. The change of the liver SUVmean correlated inversely with the change of tumor MTVwb and TLG after 1 week of chemotherapy (p < 0.05, respectively). The intersubject variability of liver and mediastinum [¹⁸F]FDG uptake ranged from 11 to 26 %.

CONCLUSIONS

The liver [¹⁸F]FDG uptake increased significantly after R-CHOP therapy. One of the possible reasons is the distribution of a greater fraction of the tracer to healthy tissues rather than tumor after effective chemotherapy. The variability of the liver [¹⁸F]FDG uptake during chemotherapy might affect the visual analysis of the interim PET scan and this needs to be confirmed in future studies with a large patient cohort. In addition, the intersubject variability of the liver and mediastinum [¹⁸F]FDG uptake should be considered.

Predictive Efficacy of Interim Positron Emission Tomography/Computed Tomography (PET/CT) for the Treatment of Aggressive Lymphoma

The prognostic value of whole-body positron emission tomography/computed tomography (PET/CT) with ¹⁸F-fluoro-2-deoxy-D-glucose (FDG) shortly after the onset of induction chemotherapy or mid treatment could help to predict long-term clinical outcomes in patients with Hodgkin's or Non-Hodgkin's lymphoma. However, FDG is not a tumor-specific substance, and it may accumulate to the point of being detected in a variety of benign conditions or at physiologic anatomical sites, which may give rise to false-positive interpretation. In an attempt to standardize the reporting criteria for interim PET/CT, the First International Workshop on Interim PET in Lymphoma suggested visual response criteria with the Deauville five-point scale, and the standardized uptake value (SUV) has been investigated in comparison with this visual system. A quantitative approach using the measurement of maximal SUV (SUVmax) or the reduction rate of SUVmax (ΔSUVmax) might be more appropriate in early-response PET/CT for reducing false-positive rates or for decreasing interobserver variability in interpretation. In this review, the predictive efficacy of PET/CT is discussed for the treatment of aggressive lymphoma, especially in terms of an interim PET/CT-based prognostic model.

Prognostic significance of interim PET/CT based on visual, SUV-based, and MTV-based assessment in the treatment of peripheral T-cell lymphoma

Backgrounds

The role of interim PET/CT in peripheral T-cell lymphoma (PTCL) is less identified compared to other subtype of lymphoma. This study prospectively investigated the prognostic accuracy of sequential interim PET/CT using visual and quantitative assessment to determine whether it provided prognostic information for the treatment of PTCL.

Methods

Sixty-three patients with newly diagnosed PTCL were enrolled, and 59 patients underwent interim PET/CT after three or four courses of induction treatment. The response of interim PET/CT was assessed by three parameters: the Deauville five-point scale (5-PS), ΔSUVmax, and ΔMTV2.5.

Results

Over a median follow up of 40.3 months, each assessment of interim PET/CT using the 5-PS, ΔSUVmax, and ΔMTV2.5 had predictive value for progression-free survival. To increase the predictive accuracy of interim PET/CT, we divided patients into three groups according to the sum of scores for three adverse responses based on the visual, SUV-based and MTV-based assessment: favorable, intermediate, and poor responder. The clinical outcome of patients in the favorable group was significantly superior to patients in the poor or intermediate group.

Conclusion

Visual, quantitative SUV-based, and MTV-based assessment in interim PET/CT are valuable for early treatment response assessment in patients with PTCL, and the combined approach using the three parameters was more efficient in discriminating between patients with different survival outcomes compared with single-parameter assessment.

Trial registration

NCT01470066.

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

BACKGROUND

(18)F-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).

MATERIAL AND METHODS

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).

RESULTS

All patients had one or more visualized lymphomatous lesions on (18)F-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).

CONCLUSION

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.

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 (SUV_max), 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 (ADC_min and ADC_mean) were measured on the parametric ADC maps.

Results

The SUV_max correlated inversely with the ADC_min (r = −0.35, p<0.05). The ADC_min, ADC_mean, 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 SUV_max, 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 SUV_max is superior to the ADC_min 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.

Comparison of different MRI sequences in lesion detection and early response evaluation of diffuse large B-cell lymphoma--a whole-body MRI and diffusion-weighted imaging study

To compare different MRI sequences for the detection of lesions and the evaluation of response to chemotherapy in patients with diffuse large B-cell lymphoma (DLBCL), 18 patients with histology-confirmed DLBCL underwent 3-T MRI scanning prior to and 1 week after chemotherapy. The MRI sequences included T1-weighted pre- and post-contrast, T2 -weighted with and without fat suppression, and a single-shot echo-planar diffusion-weighted imaging (DWI) with two b values (0 and 800 s/mm(2)). Conventional MRI sequence comparisons were performed using the contrast ratio between tumor and normal vertebral body instead of signal intensity. The apparent diffusion coefficient (ADC) of the tumor was measured directly on the parametric ADC map. The tumor volume was used as a reference for the evaluation of chemotherapy response. The mean tumor volume was 374 mL at baseline, and decreased by 65% 1 week after chemotherapy (p < 0.01). The T2 -weighted image with fat suppression showed a significantly higher contrast ratio compared with images from all other conventional MRI sequences, both before and after treatment (p < 0.01, respectively). The contrast ratio of the T2 -weighted image with fat suppression decreased significantly (p < 0.01), and that of the T1 -weighted pre-contrast image increased significantly (p < 0.01), after treatment. However, there was no correlation between the change in contrast ratio and tumor volume. The mean ADC value was 0.68 × 10(-3) mm(2)/s at baseline; it increased by 89% after chemotherapy (p < 0.001), and the change in ADC value correlated with the change in tumor volume (r = 0.66, p < 0.01). The baseline ADC value also correlated inversely with the percentage change in ADC after treatment (r = -0.62, p < 0.01). In conclusion, this study indicates that T2-weighted imaging with fat suppression is the best conventional sequence for the detection of lesions and evaluation of the efficacy of chemotherapy in DLBCL. DWI with ADC mapping is an imaging modality with both diagnostic and prognostic value that could complement conventional MRI.

Interim PET/CT-based prognostic model for the treatment of diffuse large B cell lymphoma in the post-rituximab era

The prognostic accuracy of interim (18)F-fluoro-2-dexoy-D-glucose positron emission tomography/computerized tomography (PET/CT) using three different methods of response assessments during rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone chemotherapy was investigated in 186 patients with newly diagnosed diffuse large B cell lymphoma (DLBCL). The response of interim PET/CT was assessed based on a combined evaluation of the Deauville five-point scale (5-PS), the rates of reduction in the maximal standardized uptake value (ΔSUVmax), and the rates of reduction in the metabolic tumor volume (ΔMTV2.5). Positivity on the 5-PS, the optimal cutoff of ΔSUVmax, or the optimal cutoff of ΔMTV2.5 could each predict disease progression. Over a median follow-up of 22.8 months, the assessment of responses based on the 5-PS, ΔSUVmax, and ΔMTV2.5 had prognostic value for progression-free survival. When patients were allocated a score of 0 to 3 depending on the presence of an inadequate response by visual, ΔSUVmax, or ΔMTV2.5, the outcomes of patients with a score of 0 were significantly superior to those with a score of 1, 2, or 3. The interim PET/CT response based on visual, SUV-based, and MTV-based assessment had significant negative predictive value for disease progression and a high potential for predicting outcomes of patients with DLBCL.

Clinical significance of standardized uptake value and maximum tumor diameter in patients with primary extranodal diffuse large B cell lymphoma

Background

Maximum standardized uptake value (SUVmax) and maximum tumor diameter (MTD) have been shown to reflect survival outcome in diffuse large B cell lymphoma (DLBCL). However, applying these values to primary extranodal DLBCL is difficult because they are separate nosological entities with differences in genetic origin. We therefore decided to evaluate whether SUVmax and MTD on 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (18-FDG) positron emission tomography (PET) would affect the survival outcome in primary extranodal DLBCL.

Methods

From October 2005 to November 2010, 76 primary extranodal DLBCL patients receiving R-CHOP therapy were analyzed. All patients had undergone an initial 18-FDG PET/CT and conventional computed tomography (CT) of the neck, chest, abdomen, and pelvis for staging. Median follow-up period was 35 months.

Results

The SUVmax and MTD cut-off values were 11.0 and 7.5 cm, respectively. SUVmax≥11.0 predicted a short progression free survival (PFS, P=0.002) and overall survival (OS, P=0.002). MTD≥7.5 cm was associated with poor PFS (P=0.003) and OS (P=0.003). High International Prognostic Index (IPI) was also associated with the survival outcome (PFS, P=0.046; OS, P=0.030). Multivariate analysis revealed that SUVmax≥11.0 (PFS, hazard ratio [HR]=10.813, P=0.024; OS, HR=6.312, P=0.015); MTD≥7.5 cm (PFS, HR=5.631, P=0.008; OS, HR=4.072, P=0.008); and high IPI (PFS, P=0.027; OS, P=0.046) were independent prognostic factors.

Conclusion

It appears that both MTD and SUVmax can be independent prognostic factors in primary extranodal DLBCL.

18F-FDG metabolic tumor volume and total glycolytic activity of oral cavity and oropharyngeal squamous cell cancer: adding value to clinical staging

(18)F-FDG metabolic tumor volume (MTV) and total glycolytic activity (TGA) have been proposed as potential prognostic imaging markers for patient outcome in human solid tumors. The purpose of this study was to establish whether MTV and TGA add prognostic information to clinical staging in patients with oral and oropharyngeal squamous cell carcinomas (SCCs).

METHODS

The Institutional Review Board approved this Health Insurance Portability and Accountability Act-compliant single-institution retrospective study. Forty-five patients with histologically proven oral or oropharyngeal SCC underwent PET/CT for initial cancer staging and were included in the study. MTV was measured using a gradient-based method (PET Edge) and fixed-threshold methods at 38%, 50%, and 60% of maximum standardized uptake value (SUV). The TGA is defined as MTV × mean SUV. Bland-Altman analysis was used to establish the reliability of the methods of segmentation. Outcome endpoints were overall survival (OS) and progression-free survival. Cox proportional hazards univariate and multivariate regression analyses were performed.

RESULTS

In Cox regression models, MTV and TGA were the only factors significantly associated with survival outcome after adjusting for all other covariates including American Joint Committee on Cancer (AJCC) stage, with hazards ratio of 1.06 (95% confidence interval, 1.01-1.10; P = 0.006) and 1.00 (95% confidence interval, 1.00-1.01; P = 0.02). The model fit was significantly better when MTV was added to AJCC stage in model I (χ(2) value change, 1.16-6.71; P = 0.01) and when TGA was added to AJCC stage in model II (χ(2) value change, 1.16-4.37; P = 0.04). The median cutoff point of 7.7 mL for primary tumor MTV was predictive of time to OS (log rank P = 0.04). The median cutoff point of 55 g for PET Edge primary tumor TGA was predictive of time to OS (log rank P = 0.08), though the result was not statistically significant.

CONCLUSION

Gradient-based segmentations of primary tumor MTV and TGA are potential (18)F-FDG markers for time to survival in patients with oral and oropharyngeal SCC and may provide prognostic information in addition to AJCC stage. These exploratory imaging markers need validation in larger cohort studies.

Role of [18F]-FDG-PET/MDCT in evaluating early response in patients with Hodgkin's lymphoma

PURPOSE

The authors evaluated the prognostic role of 18-fluoro-fluorodeoxyglucose positron emission tomography/multidetector computed tomography ([(18)F]-FDG PET/MDCT) in treating patients with Hodgkin's lymphoma (HL).

MATERIALS AND METHODS

We retrospectively evaluated 132 patients with HL studied with PET/MDCT before the start of chemotherapy (CTX) for staging purposes and again after two CTX cycles with [doxorubicin (Adriblastin), bleomycin, vinblastine, dacarbazine (ABVD_] (interim PET/MDCT), at least 30 days after the end of the last CTX cycle and/or 3 months after the end of radiotherapy, if delivered (final PET-MDCT).

RESULTS

Interim PET-MDCT was negative in 104/132 patients (79%), and their final PET-MDCT showed complete remission in 102/104 (98%) of cases, with disease recurrence/persistence in two (2%). In the remaining 28 (21%) patients, interim PET-MDCT revealed an early response in 68% of cases and chemoresistance with disease progression in 32% of cases; in these 28 patients, final PET-MDCT showed a lack of response to treatment in 43% of cases (43%) and complete remission in 57% of cases. Statistical analysis of these data showed that interim PET-MDCT had a negative predictive value of 98% and a positive predictive value of 42%, with values of sensitivity, specificity and diagnostic accuracy of 85.7%, 86.4% and 86.4%, respectively.

CONCLUSIONS

Interim PET-MDCT has a reliable prognostic role in diagnosis and treatment of patients with HL, as it helps predict which patients are more likely to achieve a complete response at the end of treatment. PET/MDCT may also lead to a change in treatment, with reduced treatment-related toxic effects and significantly reduced total costs.

Glucose metabolism correlated with cellular proliferation in diffuse large B-cell lymphoma

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.

Diffusion-weighted MRI in early chemotherapy response evaluation of patients with diffuse large B-cell lymphoma--a pilot study: comparison with 2-deoxy-2-fluoro- D-glucose-positron emission tomography/computed tomography

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.

Clinical significance of metabolic tumor volume by PET/CT in stages II and III of diffuse large B cell lymphoma without extranodal site involvement

The objective of this study was to investigate whether metabolic tumor volume (MTV) by positron emission tomography (PET) can be a potential prognostic tool when compared with Ann Arbor stage, in stages II and III nodal diffuse large B cell lymphoma (DLBCL). We evaluated 169 patients with nodal stages II and III DLBCL who underwent measurements with PET prior to rituximab combined with cyclophosphamide, adriamycin, vincristine, and prednisone (R-CHOP). Cutoff point of MTV was measured using the receiver operating characteristic (ROC) curve. During a median period of 36 months, stage II was 59.2% and III was 40.8%. Using the ROC curve, the MTV of 220 cm³ was the cutoff value. The low MTV group (<220 cm³) had longer progression-free survival (PFS) and overall survival (OS), compared with the high MTV group (≥220 cm³) (p < 0.001, p < 0.001). Stage II patients had longer survival than those in stage III (PFS, p = 0.011; OS, p = 0.001). The high MTV group had lower PFS and OS patterns, regardless of stage, compared with the low MTV group (p < 0.001, p < 0.001). Multivariate analysis revealed an association of the high MTV group with lower PFS and OS (PFS, hazard ratio (HR) = 5.300, p < 0.001; OS, HR = 7.009, p < 0.001), but not stage III (PFS, p = 0.187; OS, p = 0.054). Assessment of MTV by PET had more potential predictive power than Ann Arbor stage in the patients that received R-CHOP.

No correlation between glucose metabolism and apparent diffusion coefficient in diffuse large B-cell lymphoma: a PET/CT and DW-MRI study

PURPOSE

Both positron emission tomography/computed tomography (PET/CT) and diffusion-weighted magnetic resonance imaging (DW-MRI) are oncologic feasible techniques for evaluating the malignancy of tumors. Standardized uptake value (SUV) is a marker of tumor glucose metabolism detected by PET/CT. Apparent diffusion coefficient (ADC) measured by DWI can provide information about tissue cellularity. The aim of the study was to evaluate the correlation between SUV and ADC in untreated diffuse large B-cell lymphoma (DLBCL).

MATERIALS AND METHODS

Fifteen pre-therapy patients with histologically proven DLBCL underwent PET/CT and DWI examinations within two days. Tumor glucose metabolism was evaluated by the maximum and mean SUV (SUV(max) and SUV(mean)) on the PET/CT images. The mean ADC value was measured directly on the parametric ADC maps.

RESULTS

In total, 28 lymphoma lesions with best match PET/CT and DWI were identified and evaluated. The mean SUV(max) and SUV(mean) were 16.8 and 11.1, respectively; the mean ADC was 0.74 × 10(-3)mm(2)/s. There was no correlation between the mean ADC and the SUV(max) or SUV(mean).

CONCLUSION

SUV determined from PET/CT and ADC value measured from DWI are different indices for the diagnosis of tumor malignancy, they may provide complimentary functional information of tumor tissue.