Generation of Conventional 18F-FDG PET Images from 18F-Florbetaben PET Images Using Generative Adversarial Network: A Preliminary Study Using ADNI Dataset.

Background and Objectives: 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) (PETFDG) image can visualize neuronal injury of the brain in Alzheimer's disease. Early-phase amyloid PET image is reported to be similar to PETFDG image. This study aimed to generate PETFDG images from 18F-florbetaben PET (PETFBB) images using a generative adversarial network (GAN) and compare the generated PETFDG (PETGE-FDG) with real PETFDG (PETRE-FDG) images using the structural similarity index measure (SSIM) and the peak signal-to-noise ratio (PSNR). Materials and Methods: Using the Alzheimer's Disease Neuroimaging Initiative (ADNI) database, 110 participants with both PETFDG and PETFBB images at baseline were included. The paired PETFDG and PETFBB images included six and four subset images, respectively. Each subset image had a 5 min acquisition time. These subsets were randomly sampled and divided into 249 paired PETFDG and PETFBB subset images for the training datasets and 95 paired subset images for the validation datasets during the deep-learning process. The deep learning model used in this study is composed of a GAN with a U-Net. The differences in the SSIM and PSNR values between the PETGE-FDG and PETRE-FDG images in the cycleGAN and pix2pix models were evaluated using the independent Student's t-test. Statistical significance was set at p ≤ 0.05. Results: The participant demographics (age, sex, or diagnosis) showed no statistically significant differences between the training (82 participants) and validation (28 participants) groups. The mean SSIM between the PETGE-FDG and PETRE-FDG images was 0.768 ± 0.135 for the cycleGAN model and 0.745 ± 0.143 for the pix2pix model. The mean PSNR was 32.4 ± 9.5 and 30.7 ± 8.0. The PETGE-FDG images of the cycleGAN model showed statistically higher mean SSIM than those of the pix2pix model (p < 0.001). The mean PSNR was also higher in the PETGE-FDG images of the cycleGAN model than those of pix2pix model (p < 0.001). Conclusions: We generated PETFDG images from PETFBB images using deep learning. The cycleGAN model generated PETGE-FDG images with a higher SSIM and PSNR values than the pix2pix model. Image-to-image translation using deep learning may be useful for generating PETFDG images. These may provide additional information for the management of Alzheimer's disease without extra image acquisition and the consequent increase in radiation exposure, inconvenience, or expenses.

The Use of F-18 FDG PET-Based Cognitive Reserve to Evaluate Cognitive Decline in Alzheimer's Disease, Independent of Educational Influence.

Background and Objectives: The optimal assessment of cognitive function, including the impact of education, is crucial in managing Alzheimer's disease (AD). This study aimed to evaluate the role of cognitive reserve (CR), represented by the metabolic status of regions of the cerebral cortex, to evaluate cognitive decline considering the educational attainment of patients with AD. Materials and Methods: We used data from the Alzheimer's Disease Neuroimaging Initiative database, and selected 124 patients who underwent both baseline F-18 fluorodeoxyglucose (FDG) and F-18 florbetaben (FBB) positron emission tomography (PET) scans. Demographics, cognitive function variables (Clinical Dementia Rating-Sum of Boxes [CDR]; AD Assessment Scale 11/13 [ADAS11/13] Mini-Mental State Examination [MMSE]), and the average standardized uptake value ratio (SUVR) of cerebral cortex regions to those of the cerebellum were obtained from the data. The participants' education level was divided into low and high education subgroups using four cut-offs of 12, 14, 16, and 18 years of educational attainment (G12, G14, G16, and G18, respectively). Demographic and cognitive function variables were compared between the two subgroups in each of the four groups, and their correlations with the SUVRs were evaluated. Results: There was no significant difference between the high and low education subgroups in each of the four groups, except for ADAS11/13 and MMSE in G14 and age in G16. The SUVRs of FDG PET (FDGSUVR) were significantly correlated with CDR, ADAS11/13, and MMSE scores. FDGSUVR showed different trajectories of neurodegeneration between the low and high education groups. Conclusions: FDGSUVR correlated moderately but significantly with neuropsychological test results, without being influenced by education level. Therefore, FDG PET may reflect CR independent of education level, and therefore could be a reliable tool to evaluate cognitive decline in AD.

Assessment of Instability in Thoracolumbar Burst Fractures Using a New Bone Scan Scoring System.

Background and Objectives: Unstable thoracolumbar burst fractures require surgical management as they can result in neurological deficits if left untreated. This study aimed to evaluate whether a new bone scan scoring system could accurately assess instability in thoracolumbar burst fractures. Materials and Methods: Fifty-two patients with thoracolumbar burst fractures who underwent bone scans and magnetic resonance imaging prior to surgery between January 2015 and August 2017 at Ulsan University Hospital were selected for inclusion. Instability was determined by clinical assessment and imaging, and the Thoracolumbar Injury Classification and Severity score was determined. Bone scans were visually evaluated using a new bone scan scoring system. Bone scan findings of vertebral body (BB) and posterior column (BP) were scored separately and were summed to produce BTS {BTS (total score) = BB (body score, 5 points) + BP (posterior score, 2 points)}. The diagnostic performance of the scoring system for identifying unstable then thoracolumbar burst fractures were assessed. Results: Of the 52 thoracolumbar burst fractures, 34 (65.4%) were unstable and 31 (59.6%) had a Thoracolumbar Injury Classification and Severity score ≥ 5. The diagnostic performance of using BTS ≥ 4 to identify unstable thoracolumbar burst fractures and those with a Thoracolumbar Injury Classification and Severity score ≥ 5 was as follows: sensitivity, 61.8% and 58.1%; specificity, 94.4% and 81.0%; positive predictive value, 95.5% and 81.8%; and negative predictive value, 56.7% and 56.7%, respectively. Conclusions: The proposed bone scan scoring system has a high specificity and positive predictive value for identifying thoracolumbar burst fractures that are unstable or have a Thoracolumbar Injury Classification and Severity score ≥ 5. This scoring system may help to inform decisions regarding surgical management.

Clinicopathologic Characteristics Associated with Prognosis in Ocular Extranodal Marginal Zone B Cell Lymphoma.

Background and Objectives: Extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT) type is the most common subtype of the ocular adnexal lymphoma. Despite its excellent prognosis, some patients experience partial remission or progressive disease. We aimed to evaluate clinicopathologic differences in the treatment responder group by comparing complete remission (CR) and non-complete remission (non-CR). Materials and Methods: This study retrospectively reviewed 48 patients who were diagnosed with ocular adnexal MALT lymphoma at Ulsan University Hospital between March 2002 and August 2018. Patients who were followed up for less than 6 months were excluded. Histologic and clinical features were analyzed. The patients were divided into two groups: CR and non-CR. Results: Among the 48 patients, 33 achieved CR and 15 achieved non-CR during the median follow-up period of 40.00 months (range, 7-109 months). In univariable analysis, more patients tend to undergo treatment in the CR group, and post-radiotherapy (post-RT) SUVmax, PET and serum lactate dehydrogenase (LDH) levels were higher in the non-CR group (p = 0.043, p = 0.016, and p = 0.042, respectively). In a multivariable analysis, only application of treatment, including radiotherapy or chemotherapy with immunotherapy, was related to CR (odd ratio 7.301, 95% confidence interval 1.273-41.862, p = 0.026). In subgroup analysis according to the site of involvement, none of the variables were significant except for the post-RT SUVmax of PET and level of serum LDH in the non-conjunctiva group (p = 0.026, and p = 0.037, respectively). Seven (14.6%) patients had a recurrence, and those with a recurring site other than the primary site had a higher Ki-67 labeling index, although it was not statistically significant (9.56% vs. 18.00%, p = 0.095). Conclusions: Although belonging to the early stages, the non-CR rate was high in patients with high serum LDH levels, and recurred patients had higher Ki-67. Thus, considering active treatment is recommended in this group of patients.

Clinicopathologic risk factors of radioactive iodine therapy based on response assessment in patients with differentiated thyroid cancer: a multicenter retrospective cohort study.

PURPOSE: We investigated whether predictive clinicopathologic factors can be affected by different response criteria and how the clinical usefulness of radioactive iodine (RAI) therapy should be evaluated considering variable factors in patients with differentiated thyroid carcinoma (DTC). METHODS: A total of 1563 patients with DTC who underwent first RAI therapy after total or near total thyroidectomy were retrospectively enrolled from 25 hospitals. Response to therapy was evaluated with two different protocols based on combination of biochemical and imaging studies: (1) serum thyroglobulin (Tg) and neck ultrasonography (US) and (2) serum Tg, neck US, and radioiodine scan. The responses to therapy were classified into excellent and non-excellent or acceptable and non-acceptable to minimize the effect of non-specific imaging findings. We investigated which factors were associated with response to therapy depending on the follow-up protocols as well as response classifications. Multivariate logistic regression analysis was performed to identify factors significantly predicting response to therapy. RESULTS: The proportion of patients in the excellent response group significantly decreased from 76.5 to 59.6% when radioiodine scan was added to the follow-up protocol (P < 0.001). Preparation method (recombinant human TSH vs. thyroid hormone withdrawal) was a significant factor for excellent response prediction evaluated with radioiodine scan (OR 2.129; 95% CI 1.687-2.685; P < 0.001) but was not for other types of response classifications. Administered RAI activity, which was classified as low (1.11 GBq) or high (3.7 GBq or higher), significantly predicted both excellent and acceptable responses regardless of the follow-up protocol. CONCLUSIONS: The clinical impact of factors related to response prediction differed depending on the follow-up protocol or classification of response criteria. A high administered activity of RAI was a significant factor predicting a favorable response to therapy regardless of the follow-up protocol or classification of response criteria.

Should Total Thyroidectomy Be Recommended for Patients with Familial Non-medullary Thyroid Cancer?

BACKGROUND: It is unknown whether familial non-medullary thyroid cancer (FNMTC) has more aggressive clinical features and a worse prognosis than sporadic non-medullary thyroid cancer (SNMTC). METHODS: We retrospectively reviewed 2894 patients with differentiated thyroid cancer who underwent primary thyroidectomy, identified 391 FNMTC cases, and compared the prevalence, surgical extension, and clinicopathologic features of FNMTC and SNMTC. RESULTS: A family history of thyroid cancer was noted in 391 patients (13.5%), with 85% having two affected relatives and 15% with ≥3 affected relatives. A sibling was affected in 52.9% of cases, and in 47.1%, both parent and child were affected. There were no significant between-group differences in sex, age, tumor size, extrathyroidal extension, or central lymph node metastases. Significantly more patients with FNMTC exhibited multifocal disease (p = 0.020) or benign nodules (p = 0.015). Lateral neck lymph node metastases were noted in 6.6% (SNMTC) and 9.7% (FNMTC, p = 0.021) of patients. Multifocality and combined benign masses were more frequently observed in patients with FNMTC in multivariate analysis. In the FNMTC group, seven experienced disease recurrence, with no mortality noted during follow-up. CONCLUSIONS: FNMTC is not more aggressive than SNMTC; however, FNMTC should be treated with total thyroidectomy because of the increased disease multifocality and the presence of benign nodules. Lateral neck lymph node metastases were more likely in patients with FNMTC, although we could not estimate prognosis. All patients with thyroid cancer should be checked for family disease history and undergo preoperative ultrasonography to determine the extent of node dissection and the need for total thyroidectomy.

Intravertebral vacuum cleft sign: a cause of vertebral cold defect on bone scan.

A 67-year-old female presented with an acute compression fracture with an intravertebral vacuum cleft (IVC) sign of the T12 vertebra. Her bone scan demonstrated a cold defect of the fractured vertebra. Although the IVC sign is related to vertebral osteonecrosis, to the best of our knowledge, a cold defect on a bone scan has not been reported in an acute compression fracture with an IVC sign. In this case review, various imaging findings of osteonecrotic compression fractures are discussed along with a review of the current literature.

An intrapericardial ectopic thyroid mimicking metastasis in a patient with papillary thyroid cancer: Localization, differential diagnosis by 18F-FDG PET/CT and ablation by 131I.

We report a very rare case of incidental intrapericardial thyroid in a papillary thyroid cancer patient. Post ablation scan revealed iodine-131 (131I) uptake in the mid-chest. Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) was performed and showed a 18F-FDG avid lesion between the right atrium and the ascending aorta, (which was) shown to be an ectopic thyroid and not metastasis. The lesion disappeared on a 6 month follow-up 123I whole body scan while serum thyroglobulin was negative. Although intrapericardial ectopic thyroid is reported to show high iodine uptake, low 18F-FDG avidity of the lesion could be helpful in the exclusion of metastases.

Diagnostic performance of breast-specific gamma imaging in the assessment of residual tumor after neoadjuvant chemotherapy in breast cancer patients.

To evaluate the diagnostic performance of breast-specific gamma imaging (BSGI) in the assessment of residual tumor after neoadjuvant chemotherapy (NAC) in breast cancer patients, female breast cancer patients who underwent NAC, preoperative (99m)Tc-sestamibi BSGI, and subsequent definitive breast surgery were enrolled retrospectively. The accuracy of BSGI in the assessment of residual tumor presence and residual tumor size was evaluated and compared to that of magnetic resonance imaging (MRI) using pathology results as the gold standard. The sensitivity and specificity of BSGI for residual tumor detection in 122 enrolled patients were 74.0 and 72.2 %, respectively, and were comparable to those of MRI (81.7 and 72.2 %; P > 0.100). The residual tumor size was significantly underestimated by BSGI in the luminal subtype (P = 0.008) and by MRI in the luminal (P < 0.001) and HER2 subtypes (P = 0.032), with a significantly lesser degree of underestimation by BSGI than MRI in both subtypes. In the triple-negative subtype, both BSGI and MRI generated accurate tumor size measurements. The residual cellularity of triple-negative tumors was significantly higher than that of the non-triple-negative tumors (P = 0.017). The diagnostic performance of BSGI in the assessment of residual tumor is comparable to that of MRI in breast cancer patients. The assessment of residual tumor extent by BSGI depends on the molecular subtype, but BSGI may be more accurate than MRI. Underestimation of tumor size in the luminal and/or HER2 subtypes by BSGI and MRI may be due to low-residual cellularity.

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

PURPOSE: The present study assessed the positive predictive value (PPV) of (18)F-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 (18)F-FDG PET/CT were retrospectively analyzed. The (18)F-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 (SUVmax), 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 (18)F-FDG PET/CT prior to treatment. Excluding 33 cases of stage IV breast cancer, 62 of 216 patients had visible IMNs on (18)F-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 SUVmax and size were 3.5 ± 4.3 and 5.6 ± 2.0 mm, respectively. CONCLUSION: (18)F-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.

(18)F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography findings are different between invasive and noninvasive pulmonary aspergillosis.

OBJECTIVE: Invasive pulmonary aspergillosis (IPA) is a significant cause of morbidity and mortality especially in immunocompromised patients, and extensive work has been done in the field of diagnostic imaging. The purpose of our study was to evaluate functional metabolic image findings of F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) in the patients with invasive and noninvasive forms of pulmonary aspergillosis (IPA and NIPA, respectively). METHODS: We retrospectively reviewed 24 consecutive patients who had pulmonary aspergillosis among the patients who underwent F-FDG PET/CT to evaluate lung mass or fever of unknown origin. Demographic feature, multiplicity, visually analyzed F-FDG uptake patterns (isometabolic halo, isometabolic nodule, hypermetabolic nodule, or other), and the peak standardized uptake value (SUVpeak) of the pulmonary lesions on PET/CT were evaluated. RESULTS: Of these 24 patients, 8 were diagnosed with IPA and 16 with NIPA. Patients with IPA were significantly younger (48 vs 62 years), and immunocompromised conditions were more frequently observed in these cases (88% vs 6%). Multiple lesions were noted in 50% (4 of 8) and 19% (3 of 16) of IPA and NIPA patients, respectively, and the predominant patterns on F-FDG PET/CT were the hypermetabolic nodule pattern (6 of 8 patients, 75%) and the isometabolic halo pattern (8 of 16 patients, 50%) in IPA and NIPA patients, respectively. The isometabolic halo pattern was not observed in IPA patients. The median SUVpeak was 4.5 (range, 1.3-8.9) and 1.6 (range, 0.5-3.1) in IPA and NIPA, respectively. CONCLUSIONS: F-FDG PET/CT findings differ between IPA and NIPA patients. Pulmonary aspergillosis in immunocompromised status with a hypermetabolic nodule pattern on F-FDG PET/CT seems to have high possibility of IPA. In contrast, an isometabolic halo pattern and an isometabolic nodule pattern on F-FDG PET/CT seem to have high possibility of NIPA.

A Case of Adenomyosis Showing Size Reduction in a Follicular Lymphoma Patient Receiving Chemotherapy With R-Bendamustine.

ABSTRACT: We describe a case of adenomyosis that reduced in size in a patient with lymphoma on receiving chemotherapy. A 48-year-old woman with worsening left flank pain was diagnosed with follicular lymphoma. [ 18 F]FDG PET/CT revealed multiple hypermetabolic lymph nodes in the bilateral cervical, axillary, mediastinal, mesenteric, retroperitoneal, iliac, and inguinal regions. In addition, adenomyosis with mild hypermetabolism was demonstrated on [ 18 F]FDG PET/CT. The size and metabolism of adenomyosis decreased after chemotherapy with R-bendamustine; in addition, along with decrease in estradiol levels, the patient experienced amenorrhea and hot flushes. The patient was diagnosed with chemotherapy-induced early menopause.

Amyloid Arthropathy and Pseudomyopathy Associated With Multiple Myeloma Detected by 18F-Florapronol Amyloid PET/CT.

ABSTRACT: We report a case of amyloid arthropathy and pseudomyopathy with multiple myeloma, detected by amyloid PET/CT using 18F-florapronol. Bone scintigraphy and 18F-FDG PET/CT in a multiple myeloma patient revealed uneven soft tissue uptakes, especially at periarticular areas. The joint capsule and intermuscular fascia showed enhancement on CT, whereas muscle enzymes were normal. These suggested amyloid arthropathy with pseudomyopathy. 18F-Florapronol amyloid PET/CT showed extensive soft tissue uptakes. Amyloid arthropathy and pseudomyopathy were confirmed after biopsy. This is the first report of amyloid PET/CT aiding in the diagnosis of unusual presentation of systemic amyloidosis.

Feasibility of robotic thyroidectomy via hairline incision using da Vinci single port system: Initial experience with 40 consecutive cases.

BACKGROUND: This study aimed to introduce our robotic technique, which can minimize dissection extent using the da Vinci SP robotic system via hairline incision. METHODS: Forty patients underwent robotic thyroidectomy using the da Vinci SP robotic system via a hairline incision between February 2020 and April 2021 at Ulsan University Hospital. All procedures were performed successfully by one surgeon using the SP robotic system. RESULTS: Hemithyroidectomies were performed in 32 patients and total thyroidectomies in eight patients. Central neck dissection was performed in 32 patients. The overall mean operative time was 140.2 ± 50.7 min, and the mean console time was 74.0 ± 42.7 min. All patients were discharged on the second or third day after operation without any complications. CONCLUSIONS: Robotic thyroidectomy using the SP robotic system via hairline incision is technically feasible and safe, with a shorter incision length when compared with that of the Xi system.

Association between tumor 18F-fluorodeoxyglucose metabolism and survival in women with estrogen receptor-positive, HER2-negative breast cancer.

We examined whether 18F-fluorodeoxyglucose metabolism is associated with distant relapse-free survival (DRFS) and overall survival (OS) in women with estrogen receptor (ER)-positive, HER2-negative breast cancer. This was a cohort study examining the risk factors for survival that had occurred at the start of the study. A cohort from Asan Medical Center, Korea, recruited between November 2007 and December 2014, was included. Patients received anthracycline-based neoadjuvant chemotherapy. The maximum standardized uptake value (SUV) of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) was measured. The analysis included 466 women. The median (interquartile range) follow-up period without distant metastasis or death was 6.2 (5.3-7.6) years. Multivariable analysis of hazard ratio (95% confidence interval [CI]) showed that the middle and high tertiles of SUV were prognostic for DRFS (2.93, 95% CI 1.62-5.30; P < 0.001) and OS (4.87, 95% CI 1.94-12.26; P < 0.001). The 8-year DRFS rates were 90.7% (95% CI 85.5-96.1%) for those in the low tertile of maximum SUV vs. 73.7% (95% CI 68.0-79.8%) for those in the middle and high tertiles of maximum SUV. 18F-fluorodeoxyglucose PET/CT may assess the risk of distant metastasis and death in ER-positive, HER2-negative patients.

Chronic Vasitis After Mesh Herniorrhaphy: A Potential Cause of False Positive Results in 18F-FDG PET/CT Studies.

We report two cases of supra-scrotal vasitis incidentally detected in patients who had undergone mesh herniorrhaphy. PET/CT in patients undergoing lymphoma work-up and health check-up revealed hypermetabolic dilatation of vas deferens in the external iliac area. There were no symptoms, and blood test results did not indicate acute inflammation. Interestingly, both had undergone herniorrhaphy for inguinal hernia. Herniorrhaphy is reported to cause vasal complications such as obstruction or inflammation, although most are asymptomatic and probably under-reported. Chronic vasitis after herniorrhaphy may be a potential cause for false positive findings on F-FDG PET/CT in patients undergoing work-up for various oncological indications.

Clinical Utility of 18F-Florbetaben PET for Detecting Amyloidosis Associated With Multiple Myeloma: A Prospective Case-Control Study.

PURPOSE: The aims of this study were to evaluate the diagnostic performance of F-florbetaben PET/CT for detecting amyloid deposits in patients with multiple myeloma (MM) and to identify the optimal PET analysis method. METHODS: Fourteen patients with MM were prospectively enrolled (6 with amyloidosis, 8 control subjects). Dynamic imaging of the kidneys was performed for 20 minutes, and the retention ratio was obtained. At 90 minutes after injection, PET was performed. All images were assessed qualitatively and quantitatively, and the SUVmax, SUVmean, and SUVratio were obtained. Variables were compared between the amyloidosis group and the control group. Amyloid deposition was confirmed according to international consensus guidelines. RESULTS: Tracer uptake was abnormal in all patients with amyloidosis. The visual detection rate was excellent (100%) in the heart, stomach, and tongue but limited in the kidneys (50%) and poor (0%) in the esophagus, liver, and colon. F-florbetaben PET/CT identified 13 unexpected cases of abnormal uptake, confirming further amyloid deposition. Both spherical and manual volumes of interest showed similar diagnostic performance when evaluating amyloidosis in target organs. There was no significant difference in diagnostic performance between the SUVmax, SUVmean, and SUVratio. CONCLUSIONS: F-florbetaben PET/CT can accurately detect systemic amyloid deposits in patients with MM. F-florbetaben PET/CT was particularly useful in the heart, stomach, and tongue but of limited value in the esophagus, liver, and colon. F-florbetaben PET/CT can provide clinical information on organ involvement and could replace pathologic examination for diagnosis of amyloidosis in the future.

18F-FP-CIT dopamine transporter PET findings in cirrhotic patients with parkinsonism.

We report the clinical features and imaging findings of presynaptic dopamine transporter (DAT) positron emission tomography (PET) in four of patients with liver cirrhosis and concurrent parkinsonism. We also reviewed previously reported cases of cirrhosis-related parkinsonism using dopaminergic molecular imaging. Our results using 18F-radiolabeled N-(3-fluoropropyl)-2ß-carboxymethoxy-3ß-(4-iodophenyl) nortropane (FP-CIT) DAT PET in four patients with cirrhosis and parkinsonism showed two different molecular imaging patterns well related to their neurological symptoms. 18F-FP-CIT PET imaging of two patients showed normal DAT density in the striatum. Their clinical features included symmetric parkinsonism, early gait disturbances and postural instability, and the absence of resting tremor. The other two patients showed reduced striatal DAT uptake asymmetrically with a rostrocaudal gradient similar to idiopathic Parkinson's disease (IPD). They had clinical findings of hemiparkinsonism, resting tremor, without early gait disturbance or postural instability. They also showed sustained response to levodopa treatment. Based on the structured review of 21 cases with cirrhosis-related parkinsonism in the literature including the present cases, we categorized cirrhotic parkinsonism into three groups. Eleven of the twenty-one cases were categorized into group 1; levodopa-resistant atypical parkinsonism without a dopaminergic deficit in molecular imaging similar to primary manganism. Another 6 cases were categorized into group 2; coincidental IPD with superimposed cirrhosis with sustained good response to levodopa and presynaptic dopaminergic deficit with rostrocaudal gradient typical of IPD. The other undetermined 4 cases were categorized into group 3. They showed symmetric parkinsonism with variable response to levodopa therapy. Their molecular imaging showed a global diffuse dopaminergic deficit in the presynaptic molecular imaging distinct to group 1 (normal uptake) or 2 (asymmetric rostrocaudal deficit). In conclusion, cirrhosis-related parkinsonism is a heterogeneous disorder.

Clinical impact of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography in patients with resectable pancreatic cancer: diagnosing lymph node metastasis and predicting survival.

PURPOSE: To evaluate the diagnostic accuracy of fluorine-18-fluorodeoxyglucose PET/computed tomography (F-FDG PET/CT) for lymph node (LN) metastasis and the prognostic significance of F-FDG PET/CT LN parameters in patients with resectable pancreatic cancer. PATIENTS AND METHODS: Patients with resectable pancreatic cancer who underwent staging F-FDG PET/CT between May 2007 and September 2016 were retrospectively enrolled and analyzed through medical record and image re-evaluation. The diagnostic accuracy of F-FDG PET/CT in predicting LN metastasis was evaluated and compared with that of contrast-enhanced abdominal computed tomography (CECT). Prognostic variables, including LN parameters assessed by F-FDG PET/CT [standardized uptake value (SUV)LN and LN/tumor SUV ratio], that affect disease-free survival (DFS) and overall survival (OS) were evaluated by regression analysis. RESULTS: When predicting LN metastasis, F-FDG PET/CT showed greater sensitivity, positive predictive value, negative predictive value, and accuracy than CECT. Among prognostic factors affecting DFS, PET-positive LN (P=0.008), and LN/tumor SUV ratio (P=0.003) were found to be significant by regression analysis. Among the variables affecting OS, lymphovascular invasion (P=0.018) and the LN/tumor SUV ratio (P=0.046) were found to be significant. CONCLUSION: F-FDG PET/CT showed higher diagnostic accuracy in predicting LN metastasis than CECT in patients with resectable pancreatic cancer. Only the LN/tumor SUV ratio of F-FDG PET/CT was an independent prognostic variable in both DFS and OS.