Prognostic Significance of Volume-Based FDG PET/CT Parameters in Patients with Locally Advanced Pancreatic Cancer Treated with Chemoradiation Therapy

Purpose

We investigated the prognostic role of volume-based parameters measured on ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) scans in patients with locally advanced pancreatic cancer (LAPC) treated with chemoradiation therapy (CRT).

Materials and Methods

We enrolled 60 patients with LAPC who underwent FDG PET/CT before CRT. Maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of primary pancreatic cancers were measured on FDG PET/CT scans. Treatment response was evaluated according to the Response Evaluation Criteria in Solid Tumors. Survival analysis was performed using the Kaplan-Meier method, and Cox proportional hazard models were used to determine independent prognostic factors.

Results

The progression-free survival (PFS), locoregional progression-free survival (LRFPS), and overall survival (OS) for this population were 6.2, 10.9, and 13.2 months, respectively. The overall treatment response rate was 16.7% at 4 weeks after CRT, and the disease control rate (DCR) was 80.0%. DCR was significantly higher in patients with low SUVmax, MTV, or TLG, and showed strong correlation with longer survival times. On univariate analysis, MTV and TLG were significant prognostic factors for PFS, LRPFS, and OS, together with pre-CRT and post-CRT CA19-9 levels. Multivariate analyses demonstrated that MTV together with the pre-CRT CA19-9 level were independent prognostic factors for PFS, LRPFS, and OS, as was TLG for LRPFS and OS.

Conclusion

MTV and the pre-CRT CA19-9 level provided independent prognostic information in patients with LAPC treated with CRT. Volume-based PET/CT parameters may be useful in identifying which subgroup of patients would benefit from radiation therapy as a part of CRT.     

Distinct patterns of regional cerebral glucose metabolism in Parkinson's disease with and without mild cognitive impairment

There is no consensus with regard to the clinical and neuroimaging characteristics of prodromal dementia in Parkinson's disease (PD). To delineate functional neuroimaging features of PD with mild cognitive impairment (PDMCI) and with no cognitive impairment (PDNC), we compared regional cerebral glucose metabolism (CMRglc) amongst 13 patients with PDMCI, 27 with PDNC, and 13 healthy controls. The PDNC patients had limited areas of hypometabolism in the frontal and occipital cortices. In the PDMCI patients, there were extensive areas of hypometabolism in the posterior cortical regions, including the temporo‐parieto‐occipital junction, medial parietal, and inferior temporal cortices. The present results suggest that posterior cortical dysfunction is the primary neuroimaging feature of PD patients at risk for dementia. © 2009 Movement Disorder Society     

The prognostic value of pretreatment 2-[18F]-fluoro-2-deoxy-d-glucose positron emission tomography scan in women with cervical cancer

There is substantial risk that prognosis determined with routine clinical staging for cervical cancer may be inaccurate. This is primarily due to understaging due to the lack of detection of nodal disease. This is particularly true for para-aortic nodal metastases. Treatment based on such staging may also be inadequate for the same reason. Positron emission tomography (PET) has been demonstrated to be useful in the staging of cervical cancer and superior to either computed tomography or magnetic resonance imaging in the detection of nodal disease. Our objective was to determine the prognostic value of pretreatment 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) PET scan in women with cervical cancer. We reviewed the records of 56 women with cervical cancer who underwent FDG PET scan prior to treatment. The primary outcome was the effect of abnormal FDG uptake consistent with metastatic nodal disease on 20-month disease-free survival. The pretreatment PET scan demonstrated abnormal FDG uptake in the pelvic nodes alone in 14 (25%) women, in pelvic and para-aortic nodes in 10 (17.9%), and in neither pelvic nor para-aortic nodes in 32 (57.1%). Women with positive pelvic nodes by PET as well as women with positive para-aortic nodes had significantly poorer 20-month disease-free survival compared to women with negative nodes (P= 0.0003 and P= 0.0017, respectively). We conclude that pretreatment FDG PET scan revealing abnormal FDG uptake consistent with nodal disease is a robust predictor of disease recurrence and may alter the therapeutic management of some patients.     

Variability and reproducibility of hepatic FDG uptake measured as SUV as well as tissue‐to‐blood background ratio using positron emission tomography in healthy humans

Introduction: To investigate variability and reproducibility of hepatic [¹⁸F]‐2‐fluoro‐2‐deoxy‐d ‐glucose (FDG) uptake in healthy individuals. Methods:  Static images were obtained 70 min after the injection of 160 MBq FDG in six healthy subjects at two occasions with 13 days’ interval. FDG uptake was adjusted for tissue‐to‐blood background ratio (T/B), or measured as standardized uptake value (SUV). Small regions of interest (ROIs) of 10 cm³ in two different hepatic regions were analysed as well as the total liver. Results: Mean SUV was 1·16 ± 0·15 and mean T/B corrected values was 1·87 ± 0·17. The maximal values were 2·70 (SUV) and 4·67 (T/B). Reproducibility was 6·7% for the mean SUV and 0·2% for the max SUV values. The corresponding figures for the T/B corrected mean values were 6·4% and for the max T/B values 13·0%. In general, the small ROIs had a comparable or even lower CV% for SUV values, but a higher CV% for T/B corrected values. Conclusions: In normal subjects hepatic FDG‐uptake is high and homogeneous with a low CV% between days. T/B corrected values are largely comparable to SUV values but not superior, probably due to the standardization of procedures and homogeneity of the subjects. The T/B corrected method is theoretically superior in a more inhomogeneous population or when using different scanners and is shown here to be easy to apply. Small ROIs of 10 cm³ are representative with respect to mean FDG uptake in the total liver and reproducibility, but do not identify the max FDG uptake.     

[F-18]-fluorodeoxyglucose PET-CT of the normal prostate gland

Objective  We determined the glucose metabolism and computed tomographic (CT) density of the normal prostate gland in relation to age and prostate size on [F-18] fluorodeoxyglucose positron emission tomography (PET)-CT. Methods  We determined the CT density (Hounsfield Units, HU) and glucose metabolism (standardized uptake value, SUV) of the normal prostate in 145 men (age range 22–97 years) on PET-CT scans which were performed for indications unrelated to prostate pathology. Correlations among SUV, HU, prostate size, and age were calculated using Pearson’s correlation coefficients, scatter plots, and linear regression trend lines. The SUV and HU values were also compared among different primary cancer types using the Kruskal-Wallis test. Results  The population average and range of the normal prostate size were 4.3 ± 0.5 cm (mean ± SD) and 2.9–5.5 cm, respectively. The population average of mean and maximum CT densities was 36.0 ± 5.1 HU (range 23-57) and 91.7 ± 20.1 HU (range 62-211), respectively. The population average of mean and maximum SUV was 1.3 ± 0.4 (range 0.1–2.7) and 1.6 ± 0.4 (range 1.1–3.7), respectively. Mean SUV tended to decrease as the prostate size increased (r = −0.16, P = 0.058). Higher mean HU was correlated with higher mean SUV (r = 0.18, P = 0.033). The strongest association was observed between age and prostate size. The prostate gets larger as age increases (r = 0.32, P < 0.001). Prostate mean SUV, max SUV, mean HU, and max HU were not significantly different among different types of primary cancers. Conclusions  Although the normal prostate size increases with age, it does not significantly affect the gland’s metabolism and CT density, and therefore age-correction of these parameters may be unnecessary.     

Potential of magnetization transfer MRI for target volume definition in patients with non‐small‐cell lung cancer

Purpose

To develop a magnetization transfer (MT) module in conjunction with a single‐shot MRI readout technique and to investigate the MT phenomenon in non‐small‐cell lung cancer (NSCLC) as an adjunct for radiation therapy planning.

Materials and Methods

A total of 10 patients with inoperable NSCLC were investigated using a 1.5T MR scanner. MT ratio (MTR) maps of several slices throughout the tumor were assessed. Each MTR‐map was acquired within a short breathhold. Fluorodeoxyglucose positron emission tomography (FDG‐PET) investigations were performed in addition to the MRI protocol. A total of 60 structures appearing conspicuous in FDG‐PET were compared with structures appearing conspicuous in corresponding MTR maps. Quantification of similarity between both modalities was performed using similarity index calculation.

Results

MTR‐maps showed different contrast than FDG‐PET images. However, structures that appeared conspicuous in FDG‐PET images, either by a marked signal enhancement or signal decrease, were found to be similarly present in MTR maps. A mean similarity index of 0.65 was calculated. MTR values of suspected atelectasis were on average lower than MTR values of tumor tissue.

Conclusion

The proposed MT‐MRI technique provides a high MT efficiency, while being robust and fast enough for breathhold acquisition. The results obtained encourage for further exploration of MT‐MRI as an adjunct for radiotherapy planning in NSCLC. J. Magn. Reson. Imaging 2008;28:1417–1424. © 2008 Wiley‐Liss, Inc.     

High 2-Deoxy-2[F-18]fluoro-<Emphasis Type="SmallCaps">D</Emphasis>-glucose Uptake on Positron Emission Tomography in Hibernoma Originally Thought to be Myxoid Liposarcoma

Purpose The purpose of the study is to describe the rare tumor on 2-deoxy-2[F-18]fluoro-d-glucose (FDG) positron emission tomography (PET).Procedure A 33-year-old male was diagnosed with high uptake lesion on FDG-PET scanning, which was found to be hibernoma on excision.Results Hibernoma, originally confused with liposarcoma based on its PET and computed tomography presentation, was excised and correctly identified by pathology.Conclusion Although found to be benign, radiological and FDG-PET scanning results were indistinguishable from malignancy, and biopsy is required to exclude neoplasm.     

Optimization of Whole-Body Positron Emission Tomography Imaging by Using Delayed 2-Deoxy-2-[F-18]fluoro-d-glucose Injection Following I.V. Insulin in Diabetic Patients

Purpose High blood glucose levels may decrease the sensitivity of 2-deoxy-2-[F-18]fluoro-d-glucose (FDG)-positron emission tomography (PET). The goal of this study was to assess whether intravenous (i.v.) insulin followed by FDG injection 60 minutes later could decrease the blood glucose level of hyperglycemic patients without altering muscular, liver, or lung FDG uptake.Methods We evaluated 53 diabetic patients with a fasting glycemia higher than 7.0 mmol/l. The control group consisted of 53 nondiabetic patients with a normal fasting glycemia. Sixty minutes before FDG injection, all diabetic patients received up to two intravenous bolus of insulin. Regions of interest were drawn over the lungs, heart, liver, skeletal muscles, and over the most active lung nodule, if present, to calculate a standardized uptake value (SUV) normalized to the lean body weight.Results After one or two boluses of insulin (mean 3.4 units), 39 diabetic patients decreased their blood glucose level from 9.4 ± 1.8 to 6.1 ± 1.3 mmol/l. In 14 patients, two doses of insulin (mean 4.5 ± 2.3 units) were not sufficient, but managed to decrease the blood glucose level from 10.6 ± 2.1 to 9.1 ± 2.1 mmol/l. There was no significant difference for the SUV calculated on the lung, liver, heart, and skeletal muscles. No differences were noted in lung tumor uptake in patients who received insulin compared to the control group.Conclusions With a sufficient waiting period between the insulin and FDG injections, an i.v. bolus of insulin makes it possible to effectively decrease glycemia of diabetic patients without increasing muscular FDG uptake.     

Rats with mammary cancer treated with toremifene and interferon: Morphometry and needle aspiration biopsy for determination of ATP and14C-fluorodeoxyglucose content

The combined and separate action of the antiestrogen toremifene (TOR) and recombinant rat gamma interferon (RIF) was studied in rat mammary cancer induced by dimethylbenzanthracene (DMBA). The content of ATP and 14C-fluorodeoxyglucose (FDG) was also determined from fine needle aspiration biopsies (FNAB). RIF alone had no antitumor activity, when measured as the average number of new tumors appearing in RIF and control animals (2.4 vs 2.4 new tumors per animal), while TOR and TOR + RIF had a significant effect (1.2, P less than 0.05 and 0.6, P less than 0.01). Morphometrically, there was a significant decrease in the amount of epithelium in the tumors of the RIF + TOR animals (65% vs 82% in the controls, P less than 0.05); there was conversely an increase in the stromal component (25% vs 14%, NS). It appears that an increase of the stromal compartment is part of the healing process. The feasibility of the FNAB-technique was shown by the finding that there was a close correlation between FDG and ATP content in almost all the groups before and after treatment. Thus, FDG and ATP measure the same phenomenon, i.e., energy content. There was a large variation in the contents of ATP and FDG within and among the groups, which invalidated considerations regarding the predictive value of ATP and FDG content in tumors subject to treatment.     

A Weight Index for the Standardized Uptake Value in 2-Deoxy-2-[F-18]fluoro-<Emphasis Type="SmallCaps">d</Emphasis>-glucose-Positron Emission Tomography

Introduction Known errors in the standardized uptake value (SUV) caused by variations in subject weights W encountered can be corrected by lean body mass or body surface area (bsa) algorithms replacing W in calculations. However this is infrequently done. The aims of the work here are: quantify sensitivity to W, encourage SUV correction with an approach minimally differing from tradition, and show what improvements in the SUV coefficient of variation (cv) for a population can be expected. Methods Selected for analyses were 2-deoxy-2-[F-18]fluoro-d-glucose (FDG) SUV data from positron emission tomography (PET) and PET/computed tomography (CT) scans at the University of Tennessee as well as from the literature. A weight sensitivity index was defined as −n=slope of ln(SUV/W) vs. lnW. The portion of the SUV variability due to this trend is removed by using the defined , or a virtually equal SUV _m using , with Q and ID being tissue specific-activity and injected dose. measures performance. Adapting to animal studies’ tradition, is preferred over the conventional . Results For FDG in adults from averaging over most tissues. In children, however, . Tissues have the same index if their influx constants are independent of W. Suggested, therefore, is a very simplified , which is dimensionless and keeps the same population averages as traditional SUVs. It achieves . Hence, for cv’s of SUVs below ∼1/3 improvements over tradition are possible, leading to F’s<0.95. Accounting additionally for height, as in SUV_bsa, gives very little improvement over the simplified approach here and gives essentially the same F’s as SUV _m . Conclusions Introduced here is a weight index useful in reducing variability and further understanding the SUV. Addressing weight sensitivity is appropriate where the cv of the SUVs is below about 1/3. Proposed is the very simple approach of using an average of an adult patient’s weight and ∼70 kg for FDG SUV calculations. Unlike other approaches the dimensionless population average of SUV _m s is unchanged from tradition.