Evaluation of Clinical Variables Affecting Myocardial Glucose Uptake in Cardiac FDG PET.

PURPOSE: Cardiac 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography (FDG PET) is widely used to assess myocardial viability in patients with ischemic heart disease. While sufficient glucose uptake is a prerequisite for accurate interpretation of cardiac viability, there are a lack of data on which clinical variables have the most significant impact on myocardial glucose metabolism. Therefore, this study was designed to evaluate several clinical variables that could affect myocardial glucose metabolism. METHODS: A total of 214 consecutive cases were retrospectively enrolled in this study. All subjects received 250 mg of acipimox and underwent glucose loading as preparation for cardiac FDG PET/CT. Three-dimensional regions of interest (ROIs) were drawn on PET/CT fusion images. Myocardial glucose uptake ratio (MGUR = SUVmax of LV myocardium/SUVmean of liver) was then calculated. Multiple clinical variables including body mass index (BMI), blood glucose levels at different times, administered insulin dosage, lipid profiles, and ejection fraction were measured and analyzed for correlation with myocardial glucose uptake. After dichotomizing the subjects based on a BMI of 25, each group's MGUR was compared. RESULTS: Myocardial uptake showed significant correlations with BMI (r = -0.162, p = 0.018), HbA1c (r = -0.150, p = 0.030), and triglyceride levels (r = -0.137, p = 0.046). No other clinical variables showed a significant correlation with myocardial glucose uptake. After multiple linear regression analysis, BMI (p = 0.032) and HbA1c (p = 0.050) showed a correlation with MGUR. In group analysis, after dividing patients based on BMI, the obese group showed significantly lower myocardial uptake than the non-obese group (3.8 ± 1.9 vs. 4.4 ± 2.1, p = 0.031). CONCLUSIONS: Among several clinical variables, BMI and HbA1c levels were related to myocardial glucose uptake. A prospective study would be needed to examine whether a protocol that additionally considers BMI and HbA1c levels is necessary for the current cardiac FDG PET protocol.

Behavioral Variant Frontotemporal Dementia With the Dominantly Affected Caudate Nucleus in 18 F-FP-CIT PET/CT.

ABSTRACT: Frontotemporal dementia is a clinical syndrome that is characterized by a progressive deterioration in behavior, personality, and/or language, with relative preservation of memory, and its phenotype and molecular basis are heterogeneous. We present a case of a 62-year-old female patient who underwent 18 F-FDG PET/CT and 18 F-FP-CIT PET/CT for differential diagnosis of psychiatric disease and types of dementia. 18 F-FDG PET/CT image showed a compatible finding for frontotemporal dementia, and 18 F-FP-CIT PET/CT image showed dominantly decreased dopamine transporter activity in the bilateral caudate nucleus.

Diffuse Cardiac Uptake Misdiagnosed as Cardiac Amyloidosis in Bone Scan.

In this presented case, a 77-year-old woman with an implanted prosthesis and ongoing knee pain underwent a bone scan using 99mTc-hydroxydiphosphonate (HDP) in suspicion for bone infection. An incidental finding from this scan revealed diffuse cardiac uptake, necessitating further diagnostic procedures to exclude the possibility of cardiac amyloidosis. In the subsequent 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scan and SPECT images, no perceptible cardiac uptake was observed at all. Upon retrospective review of the patient's medical records, she received 1000 mg of ferric carboxymaltose for iron-deficient anemia the day before the 99mTc-HDP bone scan. Therefore, it was assumed that the diffuse and temporary cardiac activity was due to the transient iron overload. We present and share these bone scan images in order to avoid possible future misinterpretation of cardiac amyloidosis.

A Rare Axillary Lymph Node Metastasis on 18F-FDG PET/CT for Staging in a Patient with Common Bile Duct Cancer.

Distant metastasis of cholangiocarcinoma is most commonly diagnosed in the liver; however, it can also be found in the lungs, distant lymph nodes, bones, and brain. Distant lymph node metastasis outside the abdominal region without concurrent abdominal metastasis is exceedingly rare in extrahepatic cholangiocarcinoma. Herein, we present interesting 18F-FDG PET/CT images of a 49-year-old male patient with common bile duct cancer. In this case, the patient, who was scheduled for surgery, unexpectedly showed axillary lymph node metastasis on a preoperative 18F-FDG PET scan, which was subsequently confirmed via histological examination. Although such cases are exceptionally rare, this accurate diagnosis prompted a modification of the treatment plan, leading to a positive therapeutic response.

AL-Type Amyloidosis Involving Stomach and Lungs in 99m Tc-DPD Bone Scan.

ABSTRACT: Systemic AL (amyloid light-chain) amyloidosis is a relatively rare disease. 99m Tc-DPD (3,3-diphosphono-1,2-pyrophosphate) bone scan is a highly sensitive diagnostic tool for cardiac amyloidosis of ATTR (transthyretin) type. In AL amyloidosis, there have been some previous reports of extracardiac DPD uptake in liver, kidney, and spleen, but not in stomach. We present 99m Tc-DPD bone scan images of AL-type amyloidosis involving stomach and lung.

18F-FES PET/CT for Characterization of Brain and Leptomeningeal Metastasis in Double Primary Cancer Patient.

ABSTRACT: The clinical value of 16α-18F-fluoro-17 ß-estradiol (18F-FES) PET in breast cancer has been widely investigated because it can visualize estrogen receptor-expressing lesions. This relatively new radiotracer adds clinical values by characterization of metastasis in double primary cancer. It also has advantage in finding small brain lesions, which has no background brain activity. Here, we present 18F-FES PET findings of brain and leptomeningeal metastases in a patient with breast and lung malignancy.

NIR irradiation-controlled drug release utilizing injectable hydrogels containing gold-labeled liposomes for the treatment of melanoma cancer.

Drug-based chemotherapy is associated with serious side effects. We developed a chemotherapeutic system comprising a chitosan hydrogel (CH-HG) containing gold cluster-labeled liposomal doxorubicin (DOX) (CH-HG-GLDOX) as an injectable drug depot system. CH-HG-GLDOX can be directly injected into tumor tissue without a surgical procedure, allowing this system to act as a reservoir for liposomal DOX. CH-HG-GLDOX enhanced the retention time of DOX in tumor tissue and controlled its release in response to near-infrared (NIR) irradiation, resulting in significant inhibition of tumor growth and reduced DOX-related toxicity. The combined effect of CH-HG-GLDOX and poly (D,L-lactide-co-glycolic acid) nanoparticle-based vaccines increased cytotoxic CD8+ T cell immunity, leading to enhanced synergistic therapeutic efficacy. CH-HG-GLDOX provides an advanced therapeutic approach for local drug delivery and controlled release of DOX, resulting in reduced toxicity. Here, we suggest a combination strategy for chemo- and immunotherapies, as well as in nanomedicine applications. STATEMENT OF SIGNIFICANCE: We developed an injectable hydrogel containing gold cluster-labeled liposomes for sustained drug release at the tumor site. Moreover, we demonstrated the combined therapeutic efficacy of a hydrogel system and a nanoparticle-based immunotherapeutic vaccine for melanoma cancer. Thus, we show a potential combination approach for chemo- and immunotherapies for cancer treatment.

Giant Cell Tumor of the Rib: Two Cases of F-18 FDG PET/CT Findings.

We report two cases of giant cell tumor arising from the rib and their F-18 FDG PET/CT findings. The two patients complained of chest wall pain, and large lobulated soft tissue masses with intense FDG uptake were seen on F-18 FDG PET/CT. A malignant tumor such as osteosarcoma or chondrosarcoma was suspected due to the large size of the mass, bony destruction, and intense FDG uptake. En bloc resection was performed and final pathologic results revealed giant cell tumor of the rib. Giant cell tumor of the rib is very rare, and larger lesions with high FDG uptake can be misdiagnosed as an intrathoracic malignancy arising from the rib, pleura, or chest wall.

The Role of F-18 FDG PET/CT in Intrahepatic Cholangiocarcinoma.

PURPOSE: The aim of this study was to evaluate the diagnostic and prognostic role of metabolic parameters of FDG PET/CT in patients with intrahepatic cholangiocarcinoma (ICC). METHODS: From December 2008 to December 2013, 76 FDG PET/CT scans performed for initial staging of ICC in a single institution (57 male and 19 female; mean age 68 ± 9 years) were retrospectively reviewed. Patients with history of other known malignancy were excluded. Detection rates of regional lymph node and distant metastasis by FDG PET/CT were analyzed in comparison with conventional imaging modalities such as CT or MRI. Metabolic parameters including maximum, peak and mean standardized uptake values (SUVmax, SUVpeak, SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), glucose corrected SUV (SUVgluc), and glucose corrected TLG (TLGgluc) were measured for the primary tumor. Cut-off values for the metabolic parameters were calculated by ROC curve analysis, and used to dichotomize the patient groups. The overall survival time (OS) was calculated and compared using the Cox proportional hazard regression analysis. RESULTS: The median duration of follow-up period was 5.4 months (interquartile range: 1.45∼15.45). FDG PET/CT showed higher sensitivity than conventional imaging modalities in detection of regional node involvement (74.5 % vs. 61.8 %, p = 0.013). In six patients, distant metastasis was identified only by FDG PET/CT. The mean SUVmax, SUVpeak, SUVmean, MTV, and TLG for the primary tumor were 8.2 ± 3.1, 6.8 ± 2.5, 4.0 ± 0.8, 192.7 ± 360.5 cm3, and 823.7 ± 1615.4, respectively. Patients with higher (≥7.3, HR: 4.280, p = 0.001), higher SUVpeak (≥6.5, HR: 2.333, p = 0.020), higher SUVmean (≥3.9, HR: 2.799, p = 0.004), higher SUVgluc (≥8.1, HR: 2.648, p = 0.012), and higher TLGgluc (≥431.6, HR: 2.186, p = 0.030) showed significantly shorter survival time. By multivariate study, operability was an independent prognostic factor for longer survival (HR: 4.113, p = 0.005). CONCLUSION: FDG PET/CT is an important diagnostic imaging tool in the nodal staging and detection of distant metastasis in ICC patients. Metabolic parameters may have a significant role as prognostic factors in patients with ICC.

Correlation of Consecutive Serum Thyroglobulin Levels During Hormone Withdrawal and Failure of Initial Radioiodine Ablation in Thyroid Cancer Patients.

OBJECTIVE: The aim of this study was to evaluate the value of thyroglobulin (Tg) kinetics during preparation of radioiodine ablation for prediction of initial radioiodine ablation failure in thyroid cancer patients. METHODS: Thyroid cancer patients after total thyroidectomy who underwent radioiodine ablation with 3-4 weeks of hormone withdrawal between May 2011 and January 2012 were included. Consecutive serum Tg levels 5-10 days before ablation (Tg1) and on the day of ablation (Tg2) were obtained. The difference between Tg1 and Tg2 (ΔTg), daily change rate of Tg (ΔTg/day) and Tg doubling time (Tg-DT) were calculated. Success of initial ablation was determined by the results of the follow-up ultrasonography, diagnostic radioiodine scan and stimulated Tg level after 6 to 20 months. RESULTS: A total of 143 patients were included. Failed ablation was reported in 52 patients. Tg2 higher than 5.6 ng/ml and Tg-DT shorter than 4.2 days were significantly related to a high risk of ablation failure. ΔTg and ΔTg/day did not show significant correlation with ablation failure. CONCLUSIONS: Thyroglobulin kinetics on consecutive blood sampling during hormone withdrawal may be helpful in predicting patients with higher risk of treatment failure of initial radioiodine ablation therapy in thyroid cancer patients.

Significance of Incidental Nasopharyngeal Uptake on (18)F-FDG PET/CT: Patterns of Benign/Physiologic Uptake and Differentiation from Malignancy.

PURPOSE: The purpose of this study was to assess the significance of incidental nasopharyngeal uptake on 18F-FDG PET/CT and to identify image patterns useful in the differentiation between benign or physiologic activity and nasopharyngeal carcinoma. METHODS: We retrospectively reviewed medical records of patients with nasopharyngeal uptakes on 18F-FDG PET/CT scans taken between January 2010 and July 2011. Patients with head and neck cancer, other metastatic head and neck lesions, or lymphoma were excluded. Total 177 patients were enrolled (Group A). PET images were reviewed for patterns of nasopharyngeal FDG uptake, presence/absence of cervical lymph node uptake and pattern of cervical node uptake. Diagnostic confirmation was made by pathology or clinical and radiological follow-up for 1 year or longer. Furthermore, initial PET/CT images of 48 patients with nasopharyngeal carcinoma (Group B) were reviewed for comparison with PET/CT images of Group A patients. RESULTS: All nasopharyngeal uptakes in Group A were confirmed to be benign. Group B showed significantly more intense FDG uptake (SUVmax of Group A 3.9 ± 1.4 vs. Group B 10.4 ± 4.6, p<0.001). and asymmetric nasopharyngeal uptake (asymmetric uptake of Group A 67.8% vs. Group B 89.6%). When SUVmax of 6.0 was used as cut off for detection of malignant nasopharyngeal uptake, the area under the ROC curve was 0.93 (95% confidence interval, 0.88-0.98), with a sensitivity of 88.1% and a specificity of 91.7%. Metastatic nodes in Group B showed higher SUVmax (Group A 2.3 ± 0.6 vs. Group B 7.1 ± 4.0, p<0.001) and larger size (short axis of Group A 5.3 ± 2.0 mm vs. Group B 13.1 ± 4.7 mm, p<0.001) than benign nodes of Group A. The majority of Group B cases demonstrated retropharyngeal lymph node uptake (70.8%), compared to only 2 cases in Group A. CONCLUSIONS: In patients without a history of underlying malignancy involving head and neck, incidental nasopharyngeal uptake on PET/CT does not indicate malignancy. However, if the nasopharyngeal uptake is intense (SUVmax≥6.0) or concomitant retropharyngeal lymph node uptake is present, the possibility of a malignant condition should be considered.