The effect of hormone therapy on physiological uptake of the endometrium on [18F]F-FDG PET in postmenopausal women.

OBJECTIVE: The effects of hormonal therapy, estrogen-based hormone replacement therapy (HRT), and anti-tumor hormone therapy, such as tamoxifen, on the physiological uptake of the endometrium on 2-deoxy-2[18F]fluoro-D-glucose ([18F]F-FDG) positron emission tomography (PET) in postmenopausal women have not been determined. We explored the effect of hormone therapy, particularly HRT, on physiological uptake in the endometrium of postmenopausal women. MATERIALS AND METHODS: Postmenopausal women receiving hormone therapy who underwent cancer screening using PET/computed tomography (CT) between June 2016 and April 2023 were included in the hormone therapy group (n = 21). Postmenopausal women with no history of hormone therapy were included in the control group (n = 49). First, the physiological endometrial uptake at menopausal age and at least 1 year thereafter was compared quantitatively (SUVmax) and qualitatively (4-point scale) in the control group, to assess when the endometrium ceased to show significant physiological [18F]F-FDG uptake after menopause. Endometrial uptake was compared between the hormone therapy and control groups. The association between HRT duration (months) and endometrial uptake (SUVmax) was evaluated. Endometrial thickness, measured using transvaginal ultrasonography, was also compared between the two groups. RESULTS: Endometrial uptake was significantly reduced both qualitatively and quantitatively (P < 0.05) at least 1 year after menopause in control patients, by which time most women (89.8%) no longer had significant endometrial uptake. The hormone therapy group (n = 21) showed higher FDG uptake in the endometrium compared to the control group (median SUVmax: 2.3 vs 1.9, P = 0.0011), as well as a higher visual score (P < 0.0001). HRT duration did not correlate with endometrial uptake (P = 0.097). Endometrial thickness in the hormone therapy group was significantly thicker than in the control group (median: 3.9 mm vs 1.8 mm, P = 0.002). CONCLUSION: Hormone therapy may affect physiological uptake in the endometrium in postmenopausal women.

18 F-FDG PET/CT Findings of Surgically Transposed Ovaries After Radical Hysterectomy in a Young Adult Patient.

ABSTRACT: A 35-year-old woman underwent 18 F-FDG PET/CT 2 months after a radical hysterectomy for uterine cervical cancer. An apparent FDG uptake was observed in an oval-shaped mass with an attached surgical clip in the right paracolic gutter. A similar non-FDG-avid mass with a clip was observed in the left. In this case, ovarian transposition had also been performed with metallic clips placed on both sides of the paracolic gutters. The increased FDG uptake in the right paracolic gutter was interpreted as physiological uptake in the right transposed ovary, not metastasis. Recognizing the possibility of FDG uptake in transposed ovaries is important.

Convolutional neural network-based program to predict lymph node metastasis of non-small cell lung cancer using 18F-FDG PET.

PURPOSE: To develop a convolutional neural network (CNN)-based program to analyze maximum intensity projection (MIP) images of 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) positron emission tomography (PET) scans, aimed at predicting lymph node metastasis of non-small cell lung cancer (NSCLC), and to evaluate its effectiveness in providing diagnostic assistance to radiologists. METHODS: We obtained PET images of NSCLC from public datasets, including those of 435 patients with available N-stage information, which were divided into a training set (n = 304) and a test set (n = 131). We generated 36 maximum intensity projection (MIP) images for each patient. A residual network (ResNet-50)-based CNN was trained using the MIP images of the training set to predict lymph node metastasis. Lymph node metastasis in the test set was predicted by the trained CNN as well as by seven radiologists twice: first without and second with CNN assistance. Diagnostic performance metrics, including accuracy and prediction error (the difference between the truth and the predictions), were calculated, and reading times were recorded. RESULTS: In the test set, 67 (51%) patients exhibited lymph node metastases and the CNN yielded 0.748 predictive accuracy. With the assistance of the CNN, the prediction error was significantly reduced for six of the seven radiologists although the accuracy did not change significantly. The prediction time was significantly reduced for five of the seven radiologists with the median reduction ratio 38.0%. CONCLUSION: The CNN-based program could potentially assist radiologists in predicting lymph node metastasis by increasing diagnostic confidence and reducing reading time without affecting diagnostic accuracy, at least in the limited situations using MIP images.

18F-FDG PET/CT Findings of G-CSF-Producing Gallbladder Cancer.

ABSTRACT: We report a case of granulocyte colony-stimulating factor (G-CSF)-producing gallbladder cancer in a 64-year-old man. Contrast-enhanced CT showed an exophytic hypoattenuation mass with peripheral enhancement in the gallbladder. 18F-FDG PET/CT showed avid FDG uptake in the gallbladder mass and diffuse FDG uptake in the bone marrow. The patient was diagnosed with G-CSF-producing gallbladder cancer based on an elevated serum level of G-CSF and histological findings. G-CSF-producing tumors are associated with a poor prognosis because of rapid progression. Early and accurate diagnosis of G-CSF-producing tumors based on characteristic PET/CT findings is important to determine treatment strategies and improve prognosis of patients.

Phantom study of SPECT/CT augmented reality for intraoperative localization of sentinel lymph nodes in head and neck melanoma.

OBJECTIVE: To show that augmented reality (AR) visualization of single-photon emission computed tomography (SPECT)/computed tomography (CT) data in 3D can be used to accurately localize targets in the head and neck region. MATERIALS AND METHODS: Eight head and neck styrofoam phantoms were painted with a mixture of radioactive solution (Tc-99m) detectable with a handheld gamma probe and fluorescent ink visible only under ultraviolet (UV) light to create 10-20 simulated lymph nodes on their surface. After obtaining SPECT/CT images of these phantoms, virtual renderings of the nodes were generated from the SPECT/CT data and displayed using a commercially available AR headset. For each of three physician evaluators, the time required to localize lymph node targets was recorded (1) using the gamma probe alone and (2) using the gamma probe while wearing the AR headset. In addition, the surface localization accuracy when using the AR headset was evaluated by measuring the misalignment between the locations visually marked by the evaluators and the ground truth locations identified using UV stimulation of the ink at the site of the nodes. RESULTS: For all three evaluators, using the AR headset significantly reduced the time to detect targets (P = 0.012, respectively) compared to using the gamma probe alone. The average misalignment between the location marked by the evaluators and the ground truth location was 8.6 mm. CONCLUSION: AR visualization of SPECT/CT data in 3D allows for accurate localization of targets in the head and neck region, and may reduce the localization time of targets.

Pilot-phase PET/CT study targeting integrin αvß6 in pancreatic cancer patients using the cystine-knot peptide-based 18F-FP-R01-MG-F2.

PURPOSE: A novel cystine-knot peptide-based PET radiopharmaceutical, 18F-FP-R01-MG-F2 (knottin), was developed to selectively bind to human integrin αvß6 which is overexpressed in pancreatic cancer. The purpose of this study is to evaluate the safety, biodistribution, dosimetry, and lesion uptake of 18F-FP-R01-MG-F2 in patients with pancreatic cancer. METHODS: Fifteen patients (6 men, 9 women) with histologically confirmed pancreatic cancer were prospectively enrolled and underwent knottin PET/CT between March 2017 and February 2021 (ClinicalTrials.gov Identifier NCT02683824). Vital signs and laboratory results were collected before and after the imaging scans. Maximum standardized uptake values (SUVmax) and mean SUV (SUVmean) were measured in 24 normal tissues and pancreatic cancer lesions for each patient. From the biodistribution data, the organ doses and whole-body effective dose were calculated using OLINDA/EXM software. RESULTS: There were no significant changes in vital signs or laboratory values that qualified as adverse events or serious adverse events. At 1 h post-injection, areas of high 18F-FP-R01-MG-F2 uptake included the pituitary gland, stomach, duodenum, kidneys, and bladder (average SUVmean: 9.7-14.5). Intermediate uptake was found in the normal pancreas (average SUVmean: 4.5). Mild uptake was found in the lungs and liver (average SUVmean < 1.0). The effective dose was calculated to be 2.538 × 10-2 mSv/MBq. Knottin PET/CT detected all known pancreatic tumors in the 15 patients, although it did not detect small peri-pancreatic lymph nodes of less than 1 cm in short diameter in two of three patients who had lymph node metastases at surgery. Knottin PET/CT detected distant metastases in the lungs (n = 5), liver (n = 4), and peritoneum (n = 2), confirmed by biopsy and/or contrast-enhanced CT. CONCLUSION: 18F-FP-R01-MG-F2 is a safe PET radiopharmaceutical with an effective dose comparable to other diagnostic agents. Evaluation of the primary pancreatic cancer and distant metastases with 18F-FP-R01-MG-F2 PET is feasible, but larger studies are required to define the role of this approach. TRIAL REGISTRATION: NCT02683824.

Combined Quantification of 18F-FDG and 68Ga-DOTATATE PET/CT for Prognosis in High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms.

RATIONALE AND OBJECTIVES: High-grade gastroenteropancreatic neuroendocrine neoplasms (G3 GEP-NENs) are pathologically classified into well differentiated neuroendocrine tumors (G3 NETs) and poorly differentiated neuroendocrine carcinomas (G3 NECs). Using a novel parameter, we examined the prognostic value of 18F-FDG and 68Ga-DOTATATE PET/CT quantification in comparison to pathologic assessment in G3 GEP-NENs. MATERIALS AND METHODS: A total of 31 patients with G3 GEP-NENs were reviewed. For each patient, the SUVmax on 18F-FDG and 68Ga-DOTATATE PET/CT were used to calculate the FDG-DOTATATE-Z (FDZ) score: a continuous parameter that increases with 68Ga-DOTATATE uptake and decreases with 18F-FDG uptake. The variation in the FDZ score with respect to pathologic variables was examined. Kaplan-Meier and Cox regression analyses were performed to evaluate the effect of FDZ score on overall survival. An external cohort of 21 patients was used for validation. RESULTS: The FDZ score was significantly higher in G3 NETs compared to G3 NECs (p<0.001), and was inversely correlated with Ki67 index (R2=0.33, p<0.001). Patients in the FDZ>0.05 group showed significantly longer survival compared to those in the FDZ≤0.05 group, with median of 34.9 vs. 12.0 months (p<0.001). On univariate regression, FDZ>0.05 (p=0.005), well differentiated disease (p=0.044), and lower Ki67 index (p=0.042) were predictors of survival. On multivariate regression, only FDZ>0.05 could independently predict longer survival with HR=0.16 (p=0.018), which was reproduced in the external validation cohort. CONCLUSION: Combined quantification of 18F-FDG and 68Ga-DOTATATE PET/CT into a novel parameter, the FDZ score, reflects the pathologic characteristics of G3 GEP-NENs and is a prognostic indicator of overall survival independent of differentiation.

Prognostic Value of Bone Marrow Metabolism on Pretreatment 18F-FDG PET/CT in Patients with Metastatic Melanoma Treated with Anti-PD-1 Therapy.

Our purpose was to investigate the prognostic value of 18F-FDG PET/CT parameters in melanoma patients before beginning therapy with antibodies to the programmed cell death 1 receptor (anti-PD-1). Methods: Imaging parameters including SUVmax, metabolic tumor volume, and the ratio of bone marrow to liver SUVmean (BLR) were measured from baseline PET/CT in 92 patients before the start of anti-PD-1 therapy. The association with survival and imaging parameters combined with clinical factors was evaluated. Clinical and laboratory data were compared between the high-BLR group (>median) and the low-BLR group (≤median). Results: Multivariate analyses demonstrated that BLR was an independent prognostic factor for progression-free and overall survival (P = 0.017 and P = 0.011, respectively). The high-BLR group had higher white blood cell counts and neutrophil counts and a higher level of C-reactive protein than the low-BLR group (P < 0.05). Conclusion: Patients with a high BLR were associated with poor progression-free and overall survival, potentially explained by evidence of systemic inflammation known to be associated with immunosuppression.

Quantitative and qualitative evaluation of sequential PET/MRI using a newly developed mobile PET system for brain imaging.

PURPOSE: To evaluate the clinical feasibility of a newly developed mobile PET system with MR-compatibility (flexible PET; fxPET), compared with conventional PET (cPET)/CT for brain imaging. METHODS: Twenty-one patients underwent cPET/CT with subsequent fxPET/MRI using 18F-FDG. As qualitative evaluation, we visually rated image quality of MR and PET images using a four-point scoring system. We evaluated overall image quality for MR, while we evaluated overall image quality, sharpness and lesion contrast. As quantitative evaluation, we compared registration accuracy between two modalities [(fxPET and MRI) and (cPET and CT)] measuring spatial coordinates. We also examined the accuracy of regional 18F-FDG uptake. RESULTS: All acquired images were of diagnostic quality and the number of detected lesions did not differ significantly between fxPET/MR and cPET/CT. Mean misregistration was significantly larger with fxPET/MRI than with cPET/CT. SUVmax and SUVmean for fxPET and cPET showed high correlations in the lesions (R = 0.84, 0.79; P < 0.001, P = 0.002, respectively). In normal structures, we also showed high correlations of SUVmax (R = 0.85, 0.87; P < 0.001, P < 0.001, respectively) and SUVmean (R = 0.83, 0.87; P < 0.001, P < 0.001, respectively) in bilateral caudate nuclei and a moderate correlation of SUVmax (R = 0.65) and SUVmean (R = 0.63) in vermis. CONCLUSIONS: The fxPET/MRI system showed image quality within the diagnostic range, registration accuracy below 3 mm and regional 18F-FDG uptake highly correlated with that of cPET/CT.

The Clinical Utility of 18F-Fluciclovine PET/CT in Biochemically Recurrent Prostate Cancer: an Academic Center Experience Post FDA Approval.

PURPOSE: To evaluate the diagnostic performance and clinical utility of 18F-fluciclovine PET/CT in patients with biochemical recurrence (BCR) of prostate cancer (PC). METHODS: 18F-Fluciclovine scans of 165 consecutive men with BCR after primary definitive treatment with prostatectomy (n = 102) or radiotherapy (n = 63) were retrospectively evaluated. Seventy patients had concurrent imaging with at least one other conventional modality (CT (n = 31), MRI (n = 31), or bone scan (n = 26)). Findings from 18F-fluciclovine PET were compared with those from conventional imaging modalities. The positivity rate and impact of 18F-fluciclovine PET on patient management were recorded. In 33 patients who underwent at least one other PET imaging (18F-NaF PET/CT (n = 12), 68Ga-PSMA11 PET/CT (n = 5), 18F-DCFPyL PET/CT (n = 20), and 68Ga-RM2 PET/MRI (n = 5)), additional findings were evaluated. RESULTS: The overall positivity rate of 18F-fluciclovine PET was 67 %, which, as expected, increased with higher prostate-specific antigen (PSA) levels (ng/ml): 15 % (PSA < 0.5), 50 % (0.5 ≤ PSA < 1), 56 % (1 ≤ PSA < 2), 68 % (2 ≤ PSA < 5), and 94 % (PSA ≥ 5), respectively. One hundred and two patients (62 %) had changes in clinical management based on 18F-fluciclovine PET findings. Twelve of these patients (12 %) had lesion localization on 18F-fluciclovine PET, despite negative conventional imaging. Treatment plans of 14 patients with negative 18F-fluciclovine PET were changed based on additional PET imaging with a different radiopharmaceutical. CONCLUSION: 18F-Fluciclovine PET/CT remains a useful diagnostic tool in the workup of patients with BCR PC, changing clinical management in 62 % of participants in our cohort.

Qualitative and Quantitative Assessment of Nonlocal Means Reconstruction Algorithm in a Flexible PET Scanner.

OBJECTIVE. Flexible PET (fxPET) was designed to fit existing MRI systems. The newly modified nonlocal means (NLM) algorithm is combined with the 3D dynamic row-action maximum likelihood algorithm (DRAMA). We investigated qualitative and quantitative acceptability of fxPET images reconstructed by modified NLM compared with whole-body (WB) PET/CT images and conventional 3D DRAMA reconstruction alone. MATERIALS AND METHODS. Fifty-nine patients with known or suspected malignancies underwent WB PET/CT scanning approximately 1 hour after the injection of 18F-FDG, after which they underwent fxPET scanning. Two readers rated the quality of fxPET images by consensus. Detection rate (the proportion of lesions found on PET), maximal standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), tumor-to-normal liver ratio (TNR), and background liver signal-to-noise ratio (SNR) were compared among the three datasets. RESULTS. Higher image quality was obtained by modified NLM reconstruction than by conventional reconstruction without statistical significance. The detection rate was comparable among three datasets. SUVmax was significantly higher, and MTV and TLG were significantly lower in the modified NLM dataset (p < 0.002) than in the other two datasets, with significantly positive correlations (p < 0.001; Spearman rank correlation coefficient, 0.87-0.99). The TNRs in modified NLM images were significantly larger than in the other datasets (p < 0.05). The background SNRs in modified NLM images were comparable with those in WB PET/CT images, and significantly higher than in the conventional fxPET images (p < 0.005). CONCLUSION. The modified NLM algorithm was clinically acceptable, yielding higher TNR and background SNR compared with conventional reconstruction. Image quality and the lesion detection rate were comparable in this population.

Imaging Characteristics and Diagnostic Performance of 2-deoxy-2-[18F]fluoro-D-Glucose PET/CT for Melanoma Patients Who Demonstrate Hyperprogressive Disease When Treated with Immunotherapy.

PURPOSE: We investigated the ability of baseline 2-deoxy-2-[18F]fluoro-D-glucose PET/CT parameters, acquired before the start of immunotherapy, to predict development of hyperprogressive disease (HPD) in melanoma patients. We also evaluated the diagnostic performances of ratios of baseline and first restaging PET/CT parameters to diagnose HPD without information of the tumor growth kinetic ratio (TGKR) that requires pre-baseline imaging before baseline imaging (3 timepoint imaging). PROCEDURES: Seventy-six patients who underwent PET/CT before and approximately 3 months following initiation of immunotherapy were included. PET/CT parameters, including metabolic tumor volume (MTV) for all melanoma lesions and total measured tumor burden (TMTB) based on irRECIST, were measured from baseline PET/CT (MTVbase and TMTBbase) and first restaging PET/CT (MTVpost and TMTBpost). The ratios of MTV (MTVpost/MTVbase, MTVr) and TMTB (TMTBpost/TMTBbase, TMTBr) were calculated. RESULTS: MTVbase of HPD patients (n = 9, TGKR ≥ 2) was larger than that of non-HPD (n = 67, TGKR < 2) patients (P < 0.05), and HPD patients demonstrated shorter median overall survival (7 vs. more than 60 months, P < 0.05). The area under the curve (AUC) of MTVbase (≥ 155.5 ml) to predict the risk of HPD was 0.703, with a sensitivity of 66.7 % and specificity of 81.2 %. The AUCs of MTVr (≥ 1.25) and TMTBr (≥ 1.27) to diagnose HPD without information of TGKR were 0.875 and 0.977 with both sensitivities of 100 %, and specificities of 79 % and 83.9 %, respectively. CONCLUSIONS: Patients at high risk of developing HPD could not be accurately identified based on baseline PET/CT parameters. The ratios of baseline and first restaging PET/CT parameters may be helpful to diagnose HPD, when patients do not undergo pre-baseline imaging.

Prognostic value of volumetric PET parameters at early response evaluation in melanoma patients treated with immunotherapy.

PURPOSE: The purpose of this study was to investigate the prognostic value of whole-body metabolic tumor volume (MTV) and other metabolic tumor parameters, obtained from baseline and first restaging 18F-FDG PET/CT scans in melanoma patients treated with immune checkpoint inhibitors (ICIs). METHODS: Eighty-five consecutive melanoma patients (M, 57; F, 28) treated with ICIs who underwent PET/CT scans before and approximately 3 months after the start of immunotherapy were retrospectively enrolled. Metabolic tumor parameters including MTV for all melanoma lesions were measured on each scan. A Cox proportional hazards model was used for univariate and multivariate analyses of metabolic parameters combined with known clinical prognostic factors associated with overall survival (OS). Kaplan-Meier curves for patients dichotomized based on median values of imaging parameters were generated. RESULTS: The median OS time in all patients was 45 months (95% CI 24-45 months). Univariate analysis demonstrated that MTV obtained from first restaging PET/CT scans (MTVpost) was the strongest prognostic factor for OS among PET/CT parameters (P < 0.0001). The median OS in patients with high MTVpost (≥ 23.44) was 16 months (95% CI 12-32 months) as compared with more than 60 months in patients with low MTVpost (< 23.44) (P = 0.0003). A multivariate model including PET/CT parameters and known clinical prognostic factors revealed that MTVpost and the presence of central nervous system lesions were independent prognostic factors for OS (P = 0.0004, 0.0167, respectively). One pseudoprogression case (1.2%) was seen in this population and classified into the high MTVpost group. CONCLUSION: Whole-body metabolic tumor volume from PET scan acquired approximately 3 months following initiation of immunotherapy (MTVpost) is a strong prognostic indicator of OS in melanoma patients. Although the possibility of pseudoprogression must be considered whenever evaluating first restaging PET imaging, it only occurred in 1 patient in our cohort.

Performance Evaluation of a Newly Developed MR-Compatible Mobile PET Scanner with Two Detector Layouts.

PURPOSE: A mobile positron emission tomography (PET) scanner called flexible PET (fxPET), designed to fit existing magnetic resonance imaging (MRI) or computed tomography (CT) system, has been developed. The purpose of this study was to evaluate the image quality, lesion detection rate, and quantitative values of fxPET compared with conventional bismuth germanium oxide (BGO)-based PET/CT without time-of-flight capability. PROCEDURES: Fifty-nine patients underwent whole-body (WB) PET/CT scans approximately 1 h after injection of 2-deoxy-2-[18F]fluoro-D-glucose, followed by the fxPET scans with detectors located above and below the patients (layout A) and with detectors closer to the patients (layout B). Two readers assessed the image quality using a 4-point grade for each layout and reached a consensus. We evaluated the differences and/or correlations between fxPET and WB PET/CT, including the lesion detection rates, the standardized uptake value (SUV), the metabolic tumor volume (MTV), the total lesion glycolysis (TLG), the tumor-to-normal liver ratio (TLR), and the background liver signal-to-noise ratio (SNR). RESULTS: The image quality of layout B was better than layout A (p < 0.0001). Of 184 lesions, the detection rate of layout B was significantly higher than WB PET/CT (p = 0.041), while the detection rate of layout A was comparable to WB PET/CT. The SUVmax/mean/peak were larger, and the MTVs were smaller in fxPET than WB PET/CT, especially in the lesions smaller than 2 cm (p < 0.01). The SUVmax/mean/peak, the MTVs and the TLGs of fxPET had significant positive correlations with WB PET/CT (p < 0.0001). The TLRs were significantly larger (p < 0.0001), but the background SNRs were significantly lower in fxPET than WB PET/CT (p < 0.05). CONCLUSIONS: The fxPET system yielded reasonable image quality and quantitative accuracy. Bringing the detectors closer to the patient yielded improved results.

Complete Spontaneous Regression of Hepatosplenic T-Cell Lymphoma After Surgical Biopsy.

F-FDG PET/CT for a 74-year-old man with elevated serum soluble interleukin 2 receptor showed multiple intense uptake in the liver, spleen, and bone. A surgical biopsy from 2 of liver tumors confirmed hepatosplenic αß T-cell lymphoma. One and a half months after biopsy, FDG PET scan was performed again for staging before starting chemotherapy, and it showed the complete disappearance of all of the lesions. The excisional biopsy could be a possible trigger of his spontaneous regression.

Correction to: Performance Evaluation of a Newly Developed MR-Compatible Mobile PET Scanner with Two Detector Layouts.

This article was updated to correct the "greater than or equal to" (≥) symbols in Tables 4 and 5, which incorrectly appeared as "greater than" (>) symbols.

Predominance and homogeneity patterns of physiological FDG accumulation in thoracic and lumbar vertebrae: suspected mechanism of "bone pseudometastasis" on FDG-PET in Japanese patients with esophageal cancer.

OBJECTIVE: False-positive bone lesions (bone pseudometastases) have been often reported in patients with esophageal cancer (EsoC). This study aimed to evaluate the vertebral 2-deoxy-2-[18F] fluoro-D-glucose (FDG) accumulation pattern in patients with newly diagnosed esophageal cancers and other malignancies (OtherT) to elucidate the possible mechanism that causes bone pseudometastasis. METHODS: FDG positron emission tomography/computed tomography performed for 90 patients with EsoC, and 112 patients with OtherT was retrospectively evaluated. The uptake pattern in the thoracic (Th) and lumbar (L) vertebrae was visually assessed regarding predominance (TL, Th ≒ L; Td, Th > L; Ld, L > Th), main intensity compared with the uptake in the blood pool (BP) (Grade 1 < BP, Grade 2 ≒ BP, or Grade 3 > BP), and homogeneity (homogeneous, heterogeneous, marginal, or spotty). The patterns between EsoC and OtherT and between Th and L were compared. RESULTS: TL, Td, and Ld patterns were observed in 51.1%, 48.9%, and 0% in EsoC and 79.7%, 20.3%, and 0% in OtherT. Though Grade 2 was most frequently observed in both groups, the ratio of Grade 3 in Th and Grade 1 in L was significantly higher in EsoC than in OtherT. Heterogeneous and spotty patterns were more frequently observed in L and in EsoC, and these were strongly associated with Td pattern. CONCLUSION: Td pattern was frequently seen, especially in EsoC, and was strongly associated with a heterogeneous or marginal pattern in the L. Heterogeneous marrow distribution with declined lumbar uptake is suspected as the mechanism of bone pseudometastasis.

Diffusely Decreased Liver Uptake on FDG PET and Cancer-Associated Cachexia With Reduced Survival.

OBJECTIVES: We investigated clinical characteristics of patients with extremely increased or decreased physiologic F-FDG uptake of the liver and their prognosis. METHODS: One thousand four hundred eighty-seven PET/CT scans of patients with known or suspected malignancy were retrospectively analyzed. A spherical volume of interest (3 cm in diameter) was set on the right lobe of the liver to calculate the SUVmean. Scans with extremely high (SUVmean >97.5th percentile) and low (SUVmean <2.5th percentile) FDG uptake in the liver were evaluated. Physical and laboratory data among a control group (n = 30), the extremely high liver uptake group (HG, n = 36), and the extremely low liver uptake group (LG, n = 36) were compared. Overall survival (OS) of the 3 groups was also compared. RESULTS: Body weight and body mass index in the HG (SUVmean ≥3.04) were significantly higher than those in the control group. The LG cases (SUVmean ≤1.78) had anemia, impaired liver function, and systemic inflammation. They were also in a poor nutritional state. The characteristics of LG cases had many things in common with those of cachectic patients. Indeed, 36.1% of LG cases met the diagnostic criteria for cachexia. Moreover, in LG cases with viable and/or recurrent malignant lesions on FDG PET, the proportion of cachexia increased by 52.6%. The OS of LG cases (median, 33 months) was significantly worse than that of controls and HG cases. CONCLUSIONS: Our data indicate that cancer patients with extremely decreased liver FDG uptake were likely to have cancer cachexia and a lower OS.