Τρίτη 10 Σεπτεμβρίου 2019

Bone Pseudometastasis on 18F-FDG PET in Japanese Patients With Esophageal Cancer
imagePurpose of the Report False-positive bone lesions mimicking bone metastases (bone pseudometastasis) on 18F-FDG PET/CT have often been reported in patients with esophageal cancer. We aimed to evaluate the prevalence and features of these lesions in Japanese patients with esophageal cancer. Methods In this retrospective study, we analyzed 83 FDG PET/CT studies for initial staging of esophageal cancer, and extracted patients with 1 or more localized high uptake sites with no subsequent progression, which were therefore judged to be bone pseudometastasis. The FDG PET/CT imaging features of the bone pseudometastasis were evaluated, and other available imaging and clinical features reviewed. Results Of the 83 patients, 7 had bone pseudometastasis. All 7 were males diagnosed with squamous cell cancer, of which 5 had T1a tumors. Bone pseudometastasis showed normal or ill-defined hyperdense (nonosteolytic) sites compared with the surrounding area on the CT. Additionally, accumulation in the upper vertebral levels of each case was contiguously high compared with the lumbar spines (we named this finding “contiguous accumulation”). On MRI, these findings were visualized as low signals on T1-weighted imaging (T1WI) and T2WI images but were unclear on fat-suppressed T2WI images. Conclusions Among all PET/CT performed for staging of esophageal cancer, 8.3% demonstrated bone pseudometastasis characterized by heterogeneous distribution with severe fatty degeneration of bone marrow accompanied by contiguous accumulation. Caution is required during diagnoses of bone lesions in esophageal cancer patients in Japan to prevent inappropriate therapeutic choices.
Prognostic Value of Maximum Standardized Uptake Value in 68Ga-Somatostatin Receptor Positron Emission Tomography for Neuroendocrine Tumors: A Systematic Review and Meta-analysis
imagePurpose Somatostatin receptor (SSTR) PET has become a mainstay in the diagnosis of neuroendocrine tumors (NETs) and for selecting patients for SSTR-based therapy; however, no consensus has yet been reached in terms of prognosis. A systematic review and meta-analysis was performed on the prognostic value of the maximum standardized uptake value (SUVmax) for 68Ga-SSTR PET in patients with NETs. Patients and Methods We performed a systematic search using the following keywords: PET, SSTR, NET, and prognosis. The inclusion criteria were the use of 68Ga-SSTR PET as an imaging tool, studies limited to NETs, studies that reported progression-free survival (PFS) and/or overall survival (OS), and studies that included SUVmax as a prognostic parameter. The effect of SUVmax on PFS and OS was measured in terms of the hazard ratio (HR). Results Eight eligible studies with 474 patients were finally included and analyzed. The combined HR of SUVmax on PFS was 2.31 with significance (95% confidence interval [CI], 1.34–4.00; P = 0.003). The trim and fill adjusted analysis for SUVmax on PFS demonstrated the combined HR as 1.81 with significance (95% CI, 1.11–2.95; P = 0.017), as the publication bias was found (Egger P = 0.004). The combined HR of SUVmax on OS was 2.97 with significance (95% CI, 1.71–5.15; P = 0.0001), without publication bias (Egger P = 0.929). The subgroup analysis revealed that well-differentiated NETs (grade 1 or 2) on PFS showed significance (P = 0.03); however, all grades of NETs (including grade 3) on PFS did not reach significance (P = 0.11). Tumor site and type of radiotracer did not affect the prognostic value of SUVmax. Conclusions Low SUVmax of 68Ga-SSTR PET was associated with a worse prognosis for PFS and OS in patients with NETs. Well-differentiated NETs had more prognostic value compared with all grades of NETs. The SUVmax of 68Ga-SSTR PET could be used as an objective prognosis predictor.
The Use of Random Forests to Classify Amyloid Brain PET
imagePurpose To evaluate random forests (RFs) as a supervised machine learning algorithm to classify amyloid brain PET as positive or negative for amyloid deposition and identify key regions of interest for stratification. Methods The data set included 57 baseline 18F-florbetapir (Amyvid; Lilly, Indianapolis, IN) brain PET scans in participants with severe white matter disease, presenting with either transient ischemic attack/lacunar stroke or mild cognitive impairment from early Alzheimer disease, enrolled in a multicenter prospective observational trial. Scans were processed using the MINC toolkit to generate SUV ratios, normalized to cerebellar gray matter, and clinically read by 2 nuclear medicine physicians with interpretation based on consensus (35 negative, 22 positive). SUV ratio data and clinical reads were used for supervised training of an RF classifier programmed in MATLAB. Results A 10,000-tree RF, each tree using 15 randomly selected cases and 20 randomly selected features (SUV ratio per region of interest), with 37 cases for training and 20 cases for testing, had sensitivity = 86% (95% confidence interval [CI], 42%–100%), specificity = 92% (CI, 64%–100%), and classification accuracy = 90% (CI, 68%–99%). The most common features at the root node (key regions for stratification) were (1) left posterior cingulate (1039 trees), (2) left middle frontal gyrus (1038 trees), (3) left precuneus (857 trees), (4) right anterior cingulate gyrus (655 trees), and (5) right posterior cingulate (588 trees). Conclusions Random forests can classify brain PET as positive or negative for amyloid deposition and suggest key clinically relevant, regional features for classification.
Spotlight on the Association of Radioactive Iodine Treatment With Cancer Mortality in Patients With Hyperthyroidism is Keeping the Highest Risk From Antithyroid Drugs in the Blind Spot
imageJuly 1, 2019, JAMA Internal Medicine released online an article authored by Kitahara et al entitled “Association of radioactive iodine treatment with cancer mortality in patients with hyperthyroidism.” The Altmetric Attention Score, a global indicator of interest from lay public and colleagues, skyrocketed to 223 by July 7, placing the article in the top 5% of all scored reports. The overall perception of death from cancer risk associated with 131I is inflated and not supported by evidence. As co-authors of this article, we offer previously unpublished data and analysis that (1) disputes clinical significance of the associated risk from 131I and (2) shows, again, that antithyroid drugs carry a statistically significant and a much more obvious cancer death risk.
Quality and Safety in Healthcare, Part LII: Other Lessons From Positive Psychology Regarding Burnout
The study of positive psychology has brought to light multiple ways to improve one's ability to bounce back from setbacks and deal better with stress. The individual should focus on his/her accomplishments, not dwell on mistakes, work to improve relationships with others, find meaning in work, and spend the time required to have happiness. Being able to recognize when situations are too stressful and understand the need to take breaks from them, especially by acquiring new knowledge, is important and effective. It is often quite helpful to utilize coaching based on positive psychology to improve one's resiliency and recover from burnout.
68Ga-DOTATATE Uptake in Pancreatic Metastasis of Renal Cell Carcinoma Mimicking Pancreatic Neuroendocrine Tumor
imageA 61-year-old man, with a history of prior clear cell renal cell carcinoma in remission, was referred to 68Ga-DOTATATE PET/CT for the further evaluation of pancreatic tail mass. 68Ga-DOTATATE PET/CT showed pathologically intense uptake on the pancreatic mass; subsequent biopsy of the pancreatic mass confirmed the diagnosis of clear cell renal cell carcinoma metastasis. 68Ga-DOTATATE uptake is not specific for neuroendocrine tumors. In the presence of prior malignancy, it should be kept in mind that malignancies apart from neuroendocrine tumors express somatostatin receptors, and they can show 68Ga-DOTATATE uptake.
Concomitant Prostate Carcinoma and Follicular Lymphoma: “Flip-Flop” Appearances on PSMA and FDG PET/CT Scans
imageWe report a case of a 75-year-old man with concomitant metastatic prostate cancer and progressive follicular lymphoma and the utility of molecular imaging in differentiating these 2 conditions. 18F-FDG PET/CT can offer accurate staging in many cancers, although its role in prostate cancer is limited. The role of 18F-DCFPyL (PSMA) PET/CT in prostate cancer is evolving and has been demonstrated to have a higher sensitivity than conventional bone scan and CT scan. Together, FDG and PSMA PET/CT studies may offer a noninvasive approach to individually characterize concomitant malignancies, aiding optimization of management and follow-up.
Incidental Uptake in Benign Gynecomastia on 68Ga-DOTATATE PET/CT
imageA 54-year-old man with mesenteric carcinoid tumor metastatic to the liver completed staging 68Ga-DOTATATE PET/CT demonstrating uptake in multiple hepatic lesions consistent with liver metastases with additional asymmetric increased uptake in the right greater than the left breast. Subsequent bilateral diagnostic mammogram revealed benign right greater than left gynecomastia without suspicious underlying mass. With Food and Drug Administration approval of 68Ga-DOTATATE and the increased use of this analog in neuroendocrine tumor imaging, this case illustrates a relevant example of uptake that can potentially mimic malignancy.
Tracheal Lymphoepithelioma-Like Carcinoma on FDG PET/CT
imageLymphoepithelioma-like carcinoma (LELC) in the trachea is an extremely rare disease. We present a case of a 64-year-old man with FDG-avid tracheal LELC on 18F-FDG PET/CT. Despite its rarity, LELC in the trachea should be considered as one of the possibilities in patients with a hypermetabolic mass in the trachea. If LELC in the trachea is suspected, 18F-FDG PET/CT is a useful tool for initial staging.
Normal Variant 18F-Sodium Fluoride Uptake in the Falx Cerebri Ossification
imageFalx cerebri ossification is an incidental finding. Mostly it is easy to diagnose, but can be challenging in few cases, and should be distinguished from calcified meningioma, hematoma, and meningeal infiltration. We report a case of a 46-year-old woman with breast cancer complaining of back pain. 18F-NaF PET/CT images show focal increase uptake at facet joints of L5/S1 vertebrae and both knees joints, suggesting degenerative disease. There is normal variant 18F-NaF uptake noted in the ossification at the falx cerebri. Recognition of normal and abnormal extraosseous 18F-NaF uptake is important for correct interpretation to avoid unnecessary further investigations.

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