Preoperative PET/CT standardized FDG uptake values of pelvic lymph nodes as a significant prognostic factor in patients with endometrial cancer

Purpose

Using integrated PET/CT, we evaluated the prognostic relevance of preoperative pelvic lymph node (LN) ¹⁸F-FDG uptake in endometrioid endometrial cancer.

Methods

We retrospectively reviewed patients with pathologically proven endometrial cancer who underwent preoperative ¹⁸F-FDG PET/CT scans to evaluate the prognostic significance of PET/CT parameters and other clinicopathological variables. We used Cox proportional hazards regression to examine the relationship between recurrence and the maximum standardized uptake value (SUV_max) in pelvic LNs (SUV_LN) on FDG PET/CT.

Results

Clinical data, treatment modalities and results were reviewed in 70 eligible patients. The median postsurgical follow-up was 29 months (range 6 to 95 months). Receiver-operating characteristic analysis identified the significant SUV_LN cut-off value as 15. The SUV_LN correlated with FIGO stage (P?<?0.001), LN metastasis (P?<?0.001), lymphovascular space invasion (P?<?0.001), SUV_tumour (P?=?0.001), metastatic LN size (P?=?0.004), primary tumour size (P?=?0.012), tumour grade (P?=?0.015) and depth of tumour invasion (P?=?0.035). Regression analysis showed a statistically significant association between recurrence and SUV_LN (P?=?0.002). Recurrence differed significantly (P?<?0.001) between patients with SUV_LN >15 and those with SUV_LN ≤15.

Conclusion

Preoperative pelvic LN FDG uptake exhibited a strong significant association with recurrence of endometrioid endometrial cancer.     

PET/CT studies of multiple myeloma using 18 F-FDG and 18 F-NaF: comparison of distribution patterns and tracers’ pharmacokinetics

Objective

The aim of this prospective study is to evaluate the combined use of fluorine-18 fluorodeoxyglucose (¹⁸?F-FDG) and fluorine-18 sodium fluoride (¹⁸?F-NaF) PET/CT in the skeletal assessment of patients with multiple myeloma (MM) and to compare the efficacy of these two PET tracers regarding detection of myeloma-indicative osseous lesions.

Patients and methods

The study includes 60 patients with multiple myeloma (MM) diagnosed according to standard criteria. All patients underwent dynamic (dPET/CT) scanning of the pelvis as well as whole body PET/CT studies with both tracers. The interval between the two exams was one day. Sites of focal increased ¹⁸?F-FDG uptake were considered as highly suspicious of myelomatous involvement. The lesions detected on the ¹⁸?F-NaF PET/CT scans were then correlated with those detected on ¹⁸?F-FDG PET/CT, which served as a reference. Moreover, the ¹⁸?F-FDG PET/CT results were also correlated with the low-dose CT findings. The evaluation of dPET/CT studies was based on qualitative evaluation, SUV calculation, and quantitative analysis based on a 2-tissue compartment model and a non-compartmental approach.

Results

Whole body ¹⁸?F-FDG PET/CT revealed approximately 343 focal lesions while ¹⁸?F-NaF PET/CT revealed 135 MM-indicative lesions (39 % correlation). CT demonstrated 150 lesions that correlated with those in ¹⁸?F-FDG PET/CT (44 % correlation). Six patients demonstrated a diffuse pattern of disease with ¹⁸?F-FDG, while 15 of them had a mixed (diffuse and focal) pattern of skeletal ¹⁸?F-FDG uptake. A high number of degenerative, traumatic and arthritic disease lesions were detected with ¹⁸?F-NaF PET/CT. In three patients with multiple focal ¹⁸?F-FDG-uptake, ¹⁸?F-NaF PET/CT failed to demonstrate any bone lesion. The dPET/CT scanning of the pelvic area with ¹⁸?F-FDG and ¹⁸?F-NaF revealed 77 and 24 MM-indicative lesions, respectively. Kinetic analysis of ¹⁸?F-FDG revealed the following mean values: SUV_aver?=?5.1, k₁?=?0.37 (1/min), k₃?=?0.10 (1/min), V_B?=?0.06, influx?=?0.04 (1/min), FD?=?1.28; the respective values for ¹⁸?F-NaF were SUV_average?=?10.7, k₁?=?0.25 (1/min), k₃?=?0.34 (1/min), V_B?=?0.02, influx?=?0.10 (1/min), FD?=?1.37. Apart from the correlation between V_B of ¹⁸?F-FDG and k₁ of ¹⁸?F-NaF (r?=?0.54), no other significant correlation was observed between the two tracers’ kinetic parameters. We found a significant correlation between FD and SUV_average (r?=?0.93), FD and SUV_max (r?=?0.80), FD and influx ( r?=?0.85), as well as between influx and SUV_average (r?=?0.74) for ¹⁸?F-FDG. In ¹⁸?F-NaF we observed the most significant correlations between FD and SUV_average (r?=?0.97), FD and SUV_max (r?=?0.87), and between influx and k₁ (r?=?0.72).

Conclusion

The combined use of ¹⁸?F-FDG PET/CT and ¹⁸?F-NaF PET/CT provides different molecular information regarding the biological processes that take place in a MM osseous lesion. ¹⁸?F-FDG PET/CT proved to be a more specific biomarker than ¹⁸?F-NaF PET/CT in multiple myeloma skeletal assessment.     

11C-Acetate as a new biomarker for PET/CT in patients with multiple myeloma: initial staging and postinduction response assessment

Purpose

We investigated the potential value of ¹¹C-acetate (ACT) PET/CT in characterizing multiple myeloma (MM) compared with ¹⁸F-FDG PET/CT. Bone marrow histological and whole-body (WB) MRI findings served as the reference standards.

Methods

In this prospective study, 15 untreated MM patients (10 men and 5 women, age range 48?69 years) underwent dual-tracer ¹¹C-ACT and ¹⁸F-FDG PET/CT and WB MRI for pretreatment staging, and 13 of them had repeated examinations after induction therapy. Diffuse and focal bone marrow uptake was assessed by visual and quantitative analyses, including measurement of the maximum standardized uptake value (SUV_max). Between-group differences and correlations were assessed with the Mann-Whitney U test and the Pearson test.

Results

At staging, all 15 patients had diffuse myeloma involvement upon bone marrow examination with 30–90 % of plasma cell infiltrates. Diffuse infiltration was detected in all of them (100 %) using ¹¹C-ACT with a positive correlation between bone marrow uptake values and percentages of plasma cell infiltrates (r = +0.63, p?=?0.01). In contrast, a diagnosis of diffuse infiltration could be established using ¹⁸F-FDG in only six patients (40 %). Focal lesions were shown in 13 patients on both ¹¹C-ACT PET/CT and WB MRI, and in 10 patients on ¹⁸F-FDG PET/CT. Focal lesions demonstrated ¹¹C-ACT uptake with a mean SUV_max of 11.4 ± 3.3 (range 4.6?19.6, n?=?59), which was significantly higher than the ¹⁸F-FDG uptake (mean SUV_max 6.6 ± 3.1, range 2.3?13.7, n?=?29; p?<?0.0001). After treatment, the diffuse bone marrow ¹¹C-ACT uptake showed a mean SUV_max reduction of 66 % in patients with at least a very good partial response versus 34 % in those with at most a partial response only (p?=?0.01).

Conclusion

PET/CT using ¹¹C-ACT as a biomarker showed a higher detection rate for both diffuse and focal myeloma lesions at diagnosis than using ¹⁸F-FDG, and may be valuable for response assessment.     

Correlation of breast cancer subtypes,based on estrogen receptor,progesterone receptor,and HER2, with functional imaging parameters from 68Ga-RGD PET/CT and 18F-FDG PET/CT

Purpose

Imaging biomarkers from functional imaging modalities were assessed as potential surrogate markers of disease status. Specifically, in this prospective study, we investigated the relationships between functional imaging parameters and histological prognostic factors and breast cancer subtypes.

Methods

In total, 43 patients with large or locally advanced invasive ductal carcinoma (IDC) were analyzed (47.6?±?7.5 years old). ⁶⁸Ga-Labeled arginine-glycine-aspartic acid (RGD) and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) were performed. The maximum and average standardized uptake values (SUV_max and SUV_avg) from RGD PET/CT and SUV_max and SUV_avg from FDG PET/CT were the imaging parameters used. For histological prognostic factors, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression was identified using immunohistochemistry (IHC) or fluorescent in situ hybridization (FISH). Four breast cancer subtypes, based on ER/PR and HER2 expression (ER/PR+,Her2?, ER/PR+,Her2+, ER/PR?,Her2+, and ER/PR?,Her2?), were considered.

Results

Quantitative FDG PET parameters were significantly higher in the ER-negative group (15.88?±?8.73 vs 10.48?±?6.01, p?=?0.02 for SUV_max; 9.40?±?5.19 vs 5.92?±?4.09, p?=?0.02 for SUV_avg) and the PR-negative group (8.37?±?4.94 vs 4.79?±?3.93, p?=?0.03 for SUV_avg). Quantitative RGD PET parameters were significantly higher in the HER2-positive group (2.42?±?0.59 vs 2.90?±?0.75, p?=?0.04 for SUV_max; 1.60?±?0.38 vs 1.95?±?0.53, p?=?0.04 for SUV_avg) and showed a significant positive correlation with the HER2/CEP17 ratio (r?=?0.38, p?=?0.03 for SUV_max and r?=?0.46, p?<?0.01 for SUV_avg). FDG PET parameters showed significantly higher values in the ER/PR?,Her2? subgroup versus the ER/PR+,Her2? or ER/PR+,Her2+ subgroups, while RGD PET parameters showed significantly lower values in the ER/PR?,Her2? subgroup versus the other subgroups. There was no correlation between FDG and RGD PET parameters in the overall group. Only the ER/PR?,Her2? subgroup showed a significant positive correlation between FDG and RGD PET parameters (r?=?0.59, p?=?0.03 for SUV_max).

Conclusion

⁶⁸Ga-RGD and ¹⁸F-FDG PET/CT are promising functional imaging modalities for predicting biomarkers and molecular phenotypes in breast cancer patients.     

Preoperative PET/CT FDG standardized uptake value of pelvic lymph nodes as a significant prognostic factor in patients with uterine cervical cancer

Purpose

Using integrated PET/CT, we evaluated the prognostic relevance in uterine cervical cancer of preoperative pelvic lymph node (LN) [¹⁸F]FDG uptake.

Methods

Patients with FIGO stage IB to IIA uterine cervical cancer were imaged with FDG PET/CT before radical surgery. We used Cox proportional hazards regression to examine the relationship between recurrence and the FDG maximum standardized uptake value (SUV_max) in the pelvic LN (SUV_LN) on PET/CT.

Results

Clinical data, treatment modalities, and results in 130 eligible patients were reviewed. The median postsurgical follow-up was 34 months (range 6 to 109 months). Receiver operating characteristic analysis identified SUV_LN 2.36 as the most significant cut-off value for predicting recurrence. SUV_LN was correlated with SUV_tumour (P?=?0.002), primary tumour size (P?=?0.004), and parametrial invasion (P?=?0.013). Univariate analyses showed significant associations between recurrence and SUV_LN (P?=?0.001), SUV_tumour (P?=?0.007), pelvic LN metastasis (P?=?0.002), parametrial invasion (P?<?0.001), primary tumour size (P?=?0.007), suspected LN metastasis on MRI (P?=?0.024), and FIGO stage (P?=?0.026). Multivariate analysis identified SUV_LN (P?=?0.013, hazard ratio, HR, 4.447, 95 % confidence interval, CI, 1.379 – 14.343) and parametrial invasion (P?=?0.013, HR 6.728, 95 % CI 1.497 – 30.235) as independent risk factors for recurrence. Patients with SUV_LN ≥2.36 and SUV_LN <2.36 differed significantly in terms of recurrence (HR 15.20, P?<?0.001).

Conclusion

Preoperative pelvic LN FDG uptake showed a strong significant association with uterine cervical cancer recurrence.     

Factors affecting intrapatient liver and mediastinal blood pool 18F-FDG standardized uptake value changes during ABVD chemotherapy in Hodgkin’s lymphoma

Purpose

The aim of our study was to assess the intrapatient variability of 2-deoxy-2-(¹⁸F)-fluoro-D-glucose (¹⁸F-FDG) uptake in the liver and in the mediastinum among patients with Hodgkin’s lymphoma (HL) treated with doxorubicin (Adriamycin), bleomycin, vinblastine and dacarbazine (ABVD) chemotherapy (CHT).

Methods

The study included 68 patients (30 men, 38 women; mean age 32?±?11 years) with biopsy-proven HL. According to Ann Arbor criteria, 6 were stage I, 34 were stage II, 12 were stage 3 and 16 were stage 4. All of them underwent a baseline (PET0) and an interim (PET2) ¹⁸F-FDG whole-body positron emission tomography (PET)/CT. All patients were treated after PET0 with two ABVD cycles for 2 months that ended 15?±?5 days prior to the PET2 examination. All patients were further evaluated 15?±?6 days after four additional ABVD cycles (PET6). None of the patients presented a serum glucose level higher than 107 mg/dl. The mean and maximum standardized uptake values (SUV) of the liver and mediastinum were calculated using the same standard protocol for PET0, PET2 and PET6, respectively. Data were examined by means of the Wilcoxon matched pairs test and linear regression analysis.

Results

The main results of our study were an increased liver SUV_mean in PET2 (1.76?±?0.35) as compared with that of PET0 (1.57?±?0.31; p?<?0.0001) and PET6 (1.69?±?0.28; p?=?0.0407). The same results were obtained when considering liver SUV_max in PET2 (3.13?±?0.67) as compared with that of PET0 (2.82?±?0.64; p?<?0.0001) and PET6 (2.96?±?0.52; p?=?0.0105). No significant differences were obtained when comparing mediastinum SUV_mean and SUV_max in PET0, PET2 and PET6 (p?>?0.05). Another finding is a relationship in PET0 between liver SUV_mean and SUV_max with the stage, which was lower in those patients with advanced disease (r ²?=?0.1456 and p?=?0.0013 for SUV_mean and r ²?=?0.1277 and p?=?0.0028 for SUV_max).

Conclusion

The results of our study suggest that liver ¹⁸F-FDG uptake is variable in patients with HL during the CHT treatment and the disease course and should be considered carefully when used to define the response to therapy in the interim PET in HL.     

Prognostic value of 18F-FDG PET/CT in patients with soft tissue sarcoma: comparisons between metabolic parameters

Objectives

To investigate the relationship between volume-based PET parameters and prognosis in patients with soft tissue sarcoma (STS).

Methods

We retrospectively reviewed 55 patients with pathologically proven STS who underwent pretreatment with ¹⁸?F-Fluorodeoxyglucose (¹⁸F-FDG) PET/CT. The maximum standardized uptake value (SUV_max), average SUV (SUV_avg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of primary tumors were measured using a threshold SUV as liver activity for determining the boundary of tumors. Univariate and multivariate survival analyses for overall survival were performed according to the metabolic parameters and other clinical variables.

Results

Cancer-related death occurred in 19 of 55 patients (35 %) during the follow-up period (29?±?23 months). On univariate analysis, AJCC stage (stage IV vs. I-III, hazard ratio (HR)?=?2.837, p?=?0.028), necrosis (G2 vs. G0-G1, HR?=?3.890, p?=?0.004), SUV_max (1 unit - increase, HR?=?1.146, p?=?0.008), SUV_avg (1 unit - increase, HR?=?1.469, p?=?0.032) and treatment modality (non-surgical therapy vs. surgery, HR?=?4.467, p?=?0.002) were significant predictors for overall survival. On multivariate analyses, SUV_max (HR?=?1.274, p?=?0.015), treatment modality (HR?=?3.353, p?=?0.019) and necrosis (HR?=?5.985, p?=?0.006) were identified as significant independent prognostic factors associated with decreased overall survival.

Conclusions

The SUV_max of the primary tumor is a significant independent metabolic prognostic factor for overall survival in patients with STS. Volume-based PET parameters may not add prognostic information outside of the SUV_max.     

18F-FDG uptake as a prognostic variable in primary differentiated thyroid cancer incidentally detected by PET/CT: a multicentre study

Purpose

Our aim was to investigate the association between ¹⁸F-fluorodeoxyglucose (FDG) uptake and event-free survival in patients in whom a differentiated thyroid cancer (DTC) was detected by ¹⁸F-FDG positron emission tomography (PET)/CT.

Methods

Among 884 focal ¹⁸F-FDG PET thyroid incidentalomas referred to our 4 Nuclear Medicine Departments, we investigated 54 patients in whom a DTC was confirmed and a clinical follow-up was available. The ratio between maximum standardized uptake value (SUV_max) of DTC and SUV_mean of the liver (SUV ratio) was recorded for each scan. All patients underwent total thyroidectomy and ¹³¹I remnant ablation. After a median follow-up of 39 months we assessed the outcome. The association between disease persistence/progression, ¹⁸F-FDG uptake and other risk factors (T, N, M and histological subtype) was evaluated through univariate and multivariate analyses.

Results

Of the 54 patients, 39 achieved complete remission. The remaining 15 showed persistence/progression of disease. High ¹⁸F-FDG uptake, i.e. SUV ratio ≥3, showed a low positive predictive value (48 %). Low ¹⁸F-FDG uptake (SUV ratio?<?3) displayed a high negative predictive value (93 %). The median of SUV ratios in T1–T2 (2.2), in M0 (2.7) and in non-virulent subtypes (2.7) were significantly lower (p?<?0.03) than in T3–T4 (5.0), M1 (7.3) and virulent subtypes (6.0). Kaplan-Maier analysis showed a significant association between high ¹⁸F-FDG uptake and disease persistence/progression (p?=?0.001). When we adjusted risk estimates by using a multivariate Cox model, only T (p?=?0.05) remained independently associated with disease persistence/progression.

Conclusion

An intense ¹⁸F-FDG uptake of the primary DTC is associated with persistence/progression of disease. However, when all other prognostic factors have been taken into account, ¹⁸F-FDG uptake does not add further prognostic information.     

Evaluation of intratumoural heterogeneity on 18F-FDG PET/CT for characterization of peripheral nerve sheath tumours in neurofibromatosis type 1

Purpose

The aim of the study was to evaluate the potential usefulness of intratumoural tracer uptake heterogeneity on ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT as compared to a cut-off maximum standardized uptake value (SUV_max) for characterization of peripheral nerve sheath tumours (PNSTs) in neurofibromatosis type 1 (NF1).

Methods

Fifty patients suffering from NF1 were examined by ¹⁸F-FDG PET/CT. Intralesional tracer uptake was analysed qualitatively and semi-quantitatively by measuring the mean and maximum SUV. Uptake heterogeneity was graded qualitatively using a three-point scale and semi-quantitatively by calculating an SUV-based heterogeneity index (HI_SUV). Cohen’s κ was used to determine inter- and intra-rater agreement. Histopathological evaluation and clinical as well as radiological follow-up examinations served as the reference standards.

Results

A highly significant correlation between the degree of intratumoural uptake heterogeneity on ¹⁸F-FDG PET and malignant transformation of PNSTs was observed (p?<?0.0001). Semi-quantitative HI_SUV was significantly higher in malignant PNSTs (MPNSTs) than in benign tumours (p?=?0.0002). Both intralesional heterogeneity and SUV_max could be used to identify malignant tumours with a sensitivity of 100 %. Cohen’s κ was 0.86 for inter-rater agreement and 0.88 for intra-rater agreement on heterogeneity.

Conclusion

MPNSTs in patients with NF1 demonstrate considerable intratumoural uptake heterogeneity on ¹⁸F-FDG PET/CT. Assessment of tumour heterogeneity is highly reproducible. Both tumour heterogeneity and a cut-off SUV_max may be used to sensitively identify malignant PNSTs, but the specificity is higher for the latter. A combination of both methods leads to a non-significant improvement in diagnostic performance.     

The role of early 18F-FDG PET/CT in prediction of progression-free survival after 90Y radioembolization: comparison with RECIST and tumour density criteria

Purpose

This study evaluated the ability of ¹⁸F-FDG PET/CT imaging to predict early response to ⁹⁰Y-radioembolization in comparison with contrast-enhanced CT (CECT) using RECIST and lesion density (Choi) criteria. Progression-free survival (PFS) in patients with liver metastases at 2?years and decline in tumour markers were the primary end-points of the study.

Methods

A total of 121 liver lesions were evaluated in 25 patients (14 men, 11 women) with liver-dominant metastatic colorectal cancer who underwent ¹⁸F-FDG PET/CT and CECT before and 6–8?weeks after treatment. Changes in SUV_max, tumour density measured in terms of Hounsfield units and the sum of the longest diameters (LD) were calculated for the target liver lesions in each patient. The patient responses to treatment were categorized using EORTC PET criteria, tumour density criteria (Hounsfield units) and RECIST, and were correlated with the responses of tumour markers and 2-year PFS using Kaplan-Meier plots and the log-rank test for comparison. Multivariate proportional hazards (Cox) regression analysis was performed to assess the effect of relevant prognostic factors on PFS.

Results

Using ¹⁸F-FDG PET/CT response criteria, 15 patients had a partial response (PR) and 10 patients had stable disease (SD), while using RECIST only 2 patients had a PR and 23 had SD. Two patients had a PR, 21 SD and 2 progressive disease using tumour density criteria. The mean changes in SUV_max, sum of the LDs and tumour density after treatment were 2.9?±?2.6, 7.3?±?14.4?mm and 1.9?±?13.18?HU, respectively. Patients who had a PR on ¹⁸F-FDG PET/CT had a mean decrease of 44.5?% in SUV_max compared to those with SD who had a decrease of only 10.3?%. The decreases in SUV_max and sum of the LDs were significant (p?p?p?>?0.1065). The responses on the ¹⁸F-FDG PET/CT studies were highly correlated with the responses of tumour markers (p?p?=?0.01 for CEA and p?=?0.02 for Ca19-9), while the responses on the CECT studies using both RECIST and tumour density criteria were not significantly correlated with the responses of tumour markers. The responses on ¹⁸F-FDG PET/CT studies also significantly predicted PFS (the median PFS in those with a PR was 12.0?months and in those with SD was 5?months, p?18F-FDG PET/CT studies and decreases in SUV_max of ≤2.0 were the strongest predictors of PFS.

Conclusion

Early response assessment to ⁹⁰Y-radioembolization using ¹⁸F-FDG PET/CT is superior to RECIST and tumour density, demonstrating a correlation with tumour markers and significantly predicting PFS in patients with liver metastases. This could enable early response-adapted treatment strategies to be employed.     

Anatomical and functional volume concordance between FDG PET,and T2 and diffusion-weighted MRI for cervical cancer: a hybrid PET/MR study

Purpose

To evaluate the concordance among ¹⁸F-FDG PET imaging, MR T2-weighted (T2-W) imaging and apparent diffusion coefficient (ADC) maps with diffusion-weighted (DW) imaging in cervical cancer using hybrid whole-body PET/MR.

Methods

This study prospectively included 35 patients with cervical cancer who underwent pretreatment ¹⁸F-FDG PET/MR imaging. ¹⁸F-FDG PET and MR images were fused using standard software. The percent of the maximum standardized uptake values (SUV_max) was used to contour tumours on PET images, and volumes were calculated automatically. Tumour volumes measured on T2-W and DW images were calculated with standard techniques of tumour area multiplied by the slice profile. Parametric statistics were used for data analysis.

Results

FDG PET tumour volumes calculated using SUV_max (14.30?±?4.70) and T2-W imaging volume (33.81?±?27.32 cm³) were similar (P?>?0.05) at 35 % and 40 % of SUV_max (32.91?±?18.90 cm³ and 27.56?±?17.19 cm³ respectively) and significantly correlated (P?<?0.001; r?=?0.735 and 0.766). The mean DW volume was 30.48?±?22.41 cm³. DW volumes were not significantly different from FDG PET volumes at either 35 % SUV_max or 40 % SUV_max or from T2-W imaging volumes (P?>?0.05). PET subvolumes with increasing SUV_max cut-off percentage showed an inverse change in mean ADC values on DW imaging (P?<?0.001, ANOVA).

Conclusion

Hybrid PET/MR showed strong volume concordance between FDG PET, and T2-W and DW imaging in cervical cancer. Cut-off at 35 % or 40 % of SUV_max is recommended for ¹⁸F-FDG PET/MR SUV-based tumour volume estimation. The linear tumour subvolume concordance between FDG PET and DW imaging demonstrates individual regional concordance of metabolic activity and cell density.     

Evaluation of the PET component of simultaneous [18F]choline PET/MRI in prostate cancer: comparison with [18F]choline PET/CT

Purpose

The aim of this study was to evaluate the positron emission tomography (PET) component of [¹⁸F]choline PET/MRI and compare it with the PET component of [¹⁸F]choline PET/CT in patients with histologically proven prostate cancer and suspected recurrent prostate cancer.

Methods

Thirty-six patients were examined with simultaneous [¹⁸F]choline PET/MRI following combined [¹⁸F]choline PET/CT. Fifty-eight PET-positive lesions in PET/CT and PET/MRI were evaluated by measuring the maximum and mean standardized uptake values (SUV_max and SUV_mean) using volume of interest (VOI) analysis. A scoring system was applied to determine the quality of the PET images of both PET/CT and PET/MRI. Agreement between PET/CT and PET/MRI regarding SUV_max and SUV_mean was tested using Pearson’s product-moment correlation and Bland-Altman analysis.

Results

All PET-positive lesions that were visible on PET/CT were also detectable on PET/MRI. The quality of the PET images was comparable in both groups. Median SUV_max and SUV_mean of all lesions were significantly lower in PET/MRI than in PET/CT (5.2 vs 6.1, p?<?0.05 and 2.0 vs 2.6, p?<?0.001, respectively). Pearson’s product-moment correlation indicated highly significant correlations between SUV_max of PET/CT and PET/MRI (R?=?0.86, p?<?0.001) as well as between SUV_mean of PET/CT and PET/MRI (R?=?0.81, p?<?0.001). Bland-Altman analysis revealed lower and upper limits of agreement of ?2.77 to 3.64 between SUV_max of PET/CT vs PET/MRI and ?1.12 to +2.23 between SUV_mean of PET/CT vs PET/MRI.

Conclusion

PET image quality of PET/MRI was comparable to that of PET/CT. A highly significant correlation between SUV_max and SUV_mean was found. Both SUV_max and SUV_mean were significantly lower in [¹⁸F]choline PET/MRI than in [¹⁸F]choline PET/CT. Differences of SUV_max and SUV_mean might be caused by different techniques of attenuation correction. Furthermore, differences in biodistribution and biokinetics of [¹⁸F]choline between the subsequent examinations and in the respective organ systems have to be taken into account.     

Prognostic value of pretreatment 18F-FDG PET/CT and human papillomavirus type 16 testing in locally advanced oropharyngeal squamous cell carcinoma

Purpose

Human papillomavirus type 16 (HPV-16) positivity is associated with favourable survival in oropharyngeal squamous cell carcinoma (OPSCC). We report here a study of the prognostic significance of ¹⁸F-FDG PET/CT functional parameters and HPV-16 infection in OPSCC patients.

Methods

We retrospectively analysed 60 patients with stage III or IV OPSCC who had had a pretherapy ¹⁸F-FDG PET/CT scan and had completed concurrent chemoradiotherapy (n?=?58) or curative radiotherapy (n?=?2). All patients were followed up for ≥24?months or until death. We determined total lesion glycolysis (TLG) and the maximal standardized uptake values (SUV_max) of the primary tumour and neck lymph nodes from the pretherapy ¹⁸F-FDG PET/CT scan. Optimal cut-offs of the ¹⁸F-FDG PET/CT parameters were obtained by receiver operating characteristic (ROC) curve analyses. Pretherapy tumour biopsies were studied by polymerase chain reaction to determine HPV infection status.

Results

The pretherapy tumour biopsies were positive for HPV-16 in 12 patients (20.0?%). Cox regression analyses revealed HPV-16 positivity and tumour TLG >135.3?g to be independently associated with overall survival (p?=?0.027 and 0.011, respectively). However, only tumour TLG >135.3?g was independently associated with progression-free survival, disease-free survival and locoregional control (p?=?0.011, 0.001 and 0.034, respectively). A scoring system was formulated to define distinct overall survival groups using tumour TLG and HPV-16 status. Patients positive for HPV-16 and with tumour TLG ≤135.3?g experienced better survival than those with tumour TLG >135.3?g and no HPV infection (p?=?0.001).

Conclusion

Tumour TLG was an independent predictor of survival in patients with locally advanced OPSCC. A scoring system was developed and may serve as a risk stratification strategy for guiding therapy.     

Standardized added metabolic activity (SAM) IN 18F-FDG PET assessment of treatment response in colorectal liver metastases

Purpose

Standardized added metabolic activity (SAM) is a PET parameter for assessing the total metabolic load of malignant processes, avoiding partial volume effects and lesion segmentation. The potential role of this parameter in the assessment of response to chemotherapy and bevacizumab was tested in patients with metastatic colorectal cancer with potentially resectable liver metastases (mCRC).

Methods

¹⁸F-FDG PET/CT was performed in 18 mCRC patients with liver metastases before treatment and after five cycles of FOLFOX/FOLFIRI and bevacizumab. Of the 18 patients, 16 subsequently underwent resection of liver metastases. Baseline and follow-up SUV_max, and SAM as well as reduction in SUV_max (?SUV_max) and SAM (?SAM) of all liver metastases were correlated with morphological response, and progression-free and overall survival (PFS and OS).

Results

A significant reduction in metabolic activity of the liver metastases was seen after chemotherapy with a median ?SUV_max of 25.3 % and ?SAM of 94.5 % (p?=?0.033 and 0.003). Median baseline SUV_max and SAM values were significantly different between morphological responders and nonresponders (3.8 vs. 7.2, p?=?0.021; and 34 vs. 211, p?=?0.002, respectively), but neither baseline PET parameters nor morphological response was correlated with PFS or OS. Follow-up SUV_max and SAM as well as ?SAM were found to be prognostic factors. The median PFS and OS in the patient group with a high follow-up SUV_max were 10.4 months and 32 months, compared to a median PFS of 14.7 months and a median OS which had not been reached in the group with a low follow-up SUV_max (p?=?0.01 and 0.003, respectively). The patient group with a high follow-up SAM and a low ?SAM had a median PFS and OS of 9.4 months and 32 months, whereas the other group had a median PFS of 14.7 months and a median OS which had not been reached (p?=?0.002 for both PFS and OS).

Conclusion

¹⁸F-FDG PET imaging is a useful tool to assess treatment response and predict clinical outcome in patients with mCRC who undergo chemotherapy before liver metastasectomy. Follow-up SUV_max, follow-up SAM and ?SAM were found to be significant prognostic factors for PFS and OS.     

Prognostic value of preoperative intratumoral FDG uptake heterogeneity in patients with epithelial ovarian cancer

Objectives

To investigate the prognostic value of intratumoral FDG uptake heterogeneity (IFH) derived from PET/CT in patients with epithelial ovarian cancer (EOC).

Methods

We retrospectively reviewed patients with pathologically proven epithelial ovarian cancer who underwent preoperative ¹⁸F-FDG PET/CT scans. PET/CT parameters such as maximum and average standardized uptake values (SUV_max and SUV_avg), sum of all metabolic tumour volume (MTV), cumulative total lesion glycolysis (TLG) and IFH were assessed. Regression analyses were used to identify clinicopathological and imaging variables associated with disease-free survival (DFS).

Results

Clinicopathological data were reviewed for 61 eligible patients. The median duration of DFS was 13 months (range, 6–26 months), and 18 (29.5 %) patients experienced recurrence. High IFH values were associated with tumour recurrence (P?=?0.005, hazard ratio 4.504, 95 % CI 1.572–12.902). The Kaplan-Meier survival graphs showed that DFS significantly differed in groups categorized based on IFH (P?=?0.002, log-rank test). Moreover, there were significant differences in DFS (P?=?0.009) and IFH (P?=?0.040) between patients with and without recurrence.

Conclusions

Preoperative IFH measured by ¹⁸F-FDG PET/CT was significantly associated with EOC recurrence. FDG-based heterogeneity could be a useful and potential predicator of EOC recurrence before treatment.

Key Points

? Preoperative IFH was significantly associated with recurrence of EOC ? Disease-free survival significantly differed in groups categorized by IFH ? FDG-based heterogeneity could be a potential predicator of EOC recurrence before treatment

     

Inverse Prognostic Relationships of <Superscript>18</Superscript>F-FDG PET/CT Metabolic Parameters in Patients with Distal Bile Duct Cancer Undergoing Curative Surgery

Purpose

As there were few previous studies with a small number of subjects, the purpose of this was to evaluate the prognostic significance of ¹⁸F-FDG PET/CT in patients with distal bile duct cancer undergoing curative surgery.

Methods

The study included 40 patients (M/F?=?24:16; age 68.0?±?8.0 years) who underwent preoperative ¹⁸F-FDG PET/CT followed by curative surgical resection. The participant’s age, sex, Eastern Cooperative Oncology Group performance-status score, baseline serum CA 19-9 level, stage, pathologic T and N stages, tumor size, tumor grade, tumor growth pattern, R0 resection, and adjuvant therapy were included as clinicopathological variables for predicting overall survival. The PET variables were maximum standardized uptake value (SUV_max), average SUV (SUV_avg), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the tumor. The Kaplan-Meyer method and Cox proportional hazards model were used for the survival analysis.

Results

A total of 15 of 40 patients (37.5%) died during the follow-up period. In univariate analysis, low SUV_max (≤?2.7, p?=?0.0005) and low SUV_avg (≤?2.6, p?=?0.0034) were significant predictors of poor overall survival. In multivariate analyses, only low SUV_max (HR?=?6.7016, 95% CI 1.9961–22.4993, p?=?0.0047) was an independent prognostic factor associated with poor overall survival.

Conclusion

The SUV_max of the primary tumor measured by ¹⁸F-FDG PET/CT was an independent significant prognostic factor for overall survival in patients with distal bile duct cancer. However, different results from a previous study warrant further large sample-sized study.

     

Diagnostic accuracy of 18F-FDG PET/CT for detection of suspected recurrence in patients with oesophageal carcinoma

Purpose

To evaluate the role of ¹⁸F-FDG PET/CT in the detection of recurrence in patients with oesophageal carcinoma, suspected clinically or following conventional investigations.

Methods

This was a retrospective study. Data from 180 patients (age 56.3?±?10.4 years; 126 men, 54 women) with histopathologically proven oesophageal carcinoma (squamous cell 115, adenocarcinoma 59, neuroendocrine carcinoma 4, small cell 1, poorly differentiated 1) who had undergone 227 ¹⁸F-FDG PET/CT studies for suspected recurrence were analysed. Recurrence was suspected clinically or following conventional investigations. PET/CT images were revaluated by two nuclear medicine physicians in consensus. Findings were grouped into local, nodal and distant recurrence. Results were compared to those from contrast-enhanced (CE) CT when available (109 patients). Clinical/imaging follow-up (minimum 6 months) with histopathology (when available) was taken as the reference standard.

Results

Of the 227 ¹⁸F-FDG PET/CT studies,166 were positive and 61 were negative for recurrent disease. PET/CT showed local recurrence in 134, nodal recurrence in 115 and distant recurrence in 47, with more than one site of recurrence in 34. The PET/CT findings were true-positive in 153 studies, true-negative in 54, false-positive in 13 and false-negative in 7. The sensitivity of ¹⁸F-FDG PET/CT was 96 %, the specificity was 81 %, the positive and negative predictive values were 92 % and 89 %, respectively, and the accuracy was 91 %. PET/CT showed similar accuracy in patients with squamous cell carcinoma and in those with adenocarcinoma (P?=?0.181).¹⁸F-FDG PET/CT was more specific than CECT (67 % vs. 21 %; P?<?0.0001). PET/CT was superior to CECT for the detection of nodal recurrence (P?<?0.0001), but not local recurrence (P?=?0.093) or distant metastases (P?=?0.441).

Conclusion

¹⁸F-FDG PET/CT shows high accuracy in the detection of suspected recurrence in patients with oesophageal carcinoma. It is more specific than and is superior to CECT in the detection of nodal recurrence.     

Detection of internal mammary lymph node metastasis with 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with stage III breast cancer

Purpose

The present study assessed the positive predictive value (PPV) of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for the detection of internal mammary node (IMN) metastasis in patients with clinical stage III breast cancer.

Methods

Patients who were diagnosed with clinical stage III breast cancer and underwent pretreatment ¹⁸F-FDG PET/CT were retrospectively analyzed. The ¹⁸F-FDG PET/CT scans were prospectively reviewed by two board-certified nuclear medicine physicians in a blinded manner. The intensities of IMNs were graded into four categories (no activity and lower, similar, and higher activities than that of the mediastinal blood pool). IMNs were measured from the combined CT (largest diameter of the short axis). Histologic data of the IMNs were obtained by ultrasonography-guided fine-needle aspiration biopsy or surgical excision. The PPV was calculated for pathologically confirmed IMNs. Visual grade, maximum standardized uptake values (SUV_max), and sizes were analyzed according to the pathology results.

Results

There were 249 clinical stage III breast cancer patients (age 48.0?±?10.1 years, range 26–79 years) who had undergone initial ¹⁸F-FDG PET/CT prior to treatment. Excluding 33 cases of stage IV breast cancer, 62 of 216 patients had visible IMNs on ¹⁸F-FDG PET/CT, and histologic confirmation was obtained in 31 patients. There were 27 metastatic and four nonmetastatic nodes (PPV 87.1 %). Metastatic nodes mostly presented with visual grade 3 (83.9 %), and SUV_max and size were 3.5?±?4.3 and 5.6?±?2.0 mm, respectively.

Conclusion

¹⁸F-FDG PET/CT has a high PPV for IMN metastasis in clinical stage III breast cancer, indicating the possibility of metastasis in IMNs with FDG uptake similar to/lower than that of the blood pool or small-sized nodes.     

Quantitative assessment of atherosclerotic plaques on <Superscript>18</Superscript>F-FDG PET/MRI: comparison with a PET/CT hybrid system

Purpose

PET with ¹⁸F-FDG has the potential to assess vascular macrophage metabolism. ¹⁸F-FDG is most often used in combination with contrast-enhanced CT to localize increased metabolism to specific arterial lesions. Novel ¹⁸F-FDG PET/MRI hybrid imaging shows high potential for the combined evaluation of atherosclerotic plaques, due to the superior morphological conspicuity of plaque lesions. The purpose of this study was to evaluate the reliability and accuracy of ¹⁸F-FDG PET/MRI uptake quantification compared to PET/CT as a reference standard in patients with carotid atherosclerotic plaques.

Methods

The study group comprised 34 consecutive oncological patients with carotid plaques who underwent both PET/CT and PET/MRI with ¹⁸F-FDG on the same day. The presence of atherosclerotic plaques was confirmed by 3 T MRI scans. Maximum standardized uptake values (SUV_max) for carotid plaque lesions and the average SUV of the blood pool within the adjacent internal jugular vein were determined and target-to-blood ratios (TBRs, plaque to blood pool) were calculated.

Results

Atherosclerotic lesions with maximum colocalized focal FDG uptake were assessed in each patient. SUV_max values of carotid plaque lesions were significantly lower on PET/MRI than on PET/CT (2.3?±?0.6 vs. 3.1?±?0.6; P?<?0.01), but were significantly correlated between PET/CT and PET/MRI (Spearman’s r?=?0.67, P?<?0.01). In contrast, TBR_max values of plaque lesions were similar on PET/MRI and on PET/CT (2.2?±?0.3 vs. 2.2?±?0.3; P?=?0.4), and again were significantly correlated between PET/MRI and PET/CT (Spearman’s r?=?0.73, P?<?0.01). Considering the increasing trend in SUV_max and TBR_max values from early to delayed imaging time-points on PET/CT and PET/MRI, respectively, with continuous clearance of radioactivity from the blood, a slight underestimation of TBR_max values may also be expected with PET/MRI compared with PET/CT.

Conclusion

SUV_max and TBR_max values are widely accepted reference parameters for estimation of the radioactivity of atherosclerotic plaques on PET/CT. However, due to a systematic underestimation of SUV_max and TBR_max with PET/MRI, the optimal cut-off values indicating the presence of inflamed plaque tissue need to be newly defined for PET/MRI.

     

18F-FDG uptake in breast cancer correlates with immunohistochemically defined subtypes

Objectives

To determine whether a correlation exists between maximum standardized uptake value (SUV_max) on ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) and the subtypes of breast cancer.

Methods

This retrospective study involved 548 patients (mean age 51.6 years, range 21–81 years) with 552 index breast cancers (mean size 2.57 cm, range 1.0–14.5 cm). The correlation between ¹⁸F-FDG uptake in PET/CT, expressed as SUV_max, and immunohistochemically defined subtypes (luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) positive and triple negative) was analyzed.

Results

The mean SUV_max value of the 552 tumours was 6.07?±?4.63 (range 0.9–32.8). The subtypes of the 552 tumours were 334 (60 %) luminal A, 66 (12 %) luminal B, 60 (11 %) HER2 positive and 92 (17 %) triple negative, for which the mean SUV_max values were 4.69?±?3.45, 6.51?±?4.18, 7.44?±?4.73 and 9.83?±?6.03, respectively. In a multivariate regression analysis, triple-negative and HER2-positive tumours had 1.67-fold (P?<?0.001) and 1.27-fold (P?=?0.009) higher SUV_max values, respectively, than luminal A tumours after adjustment for invasive tumour size, lymph node involvement status and histologic grade.

Conclusion

FDG uptake was independently associated with subtypes of invasive breast cancer. Triple-negative and HER2-positive breast cancers showed higher SUV_max values than luminal A tumours.

Key Points

? ¹⁸ F-FDG PET demonstrates increased tissue glucose metabolism, a hallmark of cancers. ? Immunohistochemically defined subtypes appear significantly associated with FDG uptake (expressed as SUV _max ). ? Triple-negative tumours had 1.67-fold higher SUV _max values than luminal A tumours. ? HER2-positive tumours had 1.27-fold higher SUV _max values than luminal A tumours.