ABSTRACT:68 Ga-DOTATATE PET/CT is indicated for selecting patients for peptide receptor radionuclide therapy (PRRT). Although highly sensitive, the detectability of smaller lesions, particularly in the liver, is lower. We present the case of a 58-year-old man with metastatic well-differentiated pancreatic neuroendocrine tumor whose MRI revealed progression of hepatic metastases. 68 Ga-DOTATATE PET/CT performed to determine eligibility for PRRT did not demonstrate DOTATATE-avid disease within the liver. 18 F-FDG PET/CT was also negative at the liver and the patient proceeded to 177 Lu-DOTATATE PRRT, where multi-time point posttherapy planar imaging and SPECT/CT showed intense uptake in the known liver metastases.

Essentials Exercise Limitation 1 year after an acute pulmonary embolism is common. Serial imaging after acute pulmonary embolism is not well described and how it affects exercise limitation remains unknown. 1 year after an acute pulmonary embolism chronic changes are common, more so on perfusion lung scanning than CT pulmonary angiography, but imaging findings did not predict exercise limitation.

A 60-year-old female with no significant medical history presented with hematuria. A computed tomography (CT) scan revealed extensive lymphadenopathy with hypodensities in the liver and spleen, and she was referred for an 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/CT (PET/CT) study to assess for malignancy of unknown primary. PET/CT revealed extensive 18F-FDG avid lymphadenopathy as well as innumerable intensely 18F-FDG avid lung, liver and splenic nodules, highly concerning for malignancy. A PET-guided bone marrow biopsy of the posterior superior iliac spine revealed several non-necrotizing, well-formed granulomas, consistent with sarcoidosis. The patient was managed conservatively and remained clinically well over the subsequent 9 years of follow-up.

A 60-year-old female with no significant medical history presented with hematuria. A computed tomography (CT) scan revealed extensive lymphadenopathy with hypodensities in the liver and spleen, and she was referred for an 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/CT (PET/CT) study to assess for malignancy of unknown primary. PET/CT revealed extensive 18F-FDG avid lymphadenopathy as well as innumerable intensely 18F-FDG avid lung, liver and splenic nodules, highly concerning for malignancy. A PET-guided bone marrow biopsy of the posterior superior iliac spine revealed several non-necrotizing, well-formed granulomas, consistent with sarcoidosis. The patient was managed conservatively and remained clinically well over the subsequent 9 years of follow-up.

BACKGROUND: We aimed to determine the frequency and predictors of exercise limitation after pulmonary embolism (PE) and to assess its association with health-related quality of life (HRQoL) and dyspnea.METHODS: One hundred patients with acute PE were recruited at five Canadian hospitals from 2010 to 2013. Cardiopulmonary exercise testing (CPET) was performed at 1 and 12 months. Quality of life (QoL), dyspnea, 6-min walk distance (6MWD), residual clot burden (perfusion scan, CT pulmonary angiography), cardiac function (echocardiography), and pulmonary function tests (PFTs) were measured during follow-up. The prespecified primary outcome was percent predicted peak oxygen uptake (Vo(2) peak) < 80% at 1-year CPET.RESULTS: At 1 year, 40 of 86 patients (46.5%) had percent predicted Vo2 peak < 80% on CPET, which was associated with significantly worse generic health-related QoL (HRQoL), PE-specific HRQoL and dyspnea scores, and significantly reduced 6MWD at 1 year. Predictors of the primary outcome included male sex (relative risk [RR], 3.2; 95% CI, 1.3-8.1), age (RR, 0.98; 95% CI, 0.96-0.99 per 1-year age increase), BMI (RR 1.1; 95% CI, 1.01-1.2 per 1 kg/m(2) BMI increase), and smoking history (RR, 1.8; 95% CI, 1.1-2.9), as well as percent predicted Vo2 peak < 80% on CPET at 1 month (RR, 3.8; 95% CI, 1.9-7.2), and 6MWD at 1 month (RR, 0.82; 95% CI, 0.7-0.9 per 30-m increased walking distance). Baseline or residual clot burden was not associated with the primary outcome. Mean PFT and echocardiographic results (pulmonary artery pressure, right and left ventricular systolic function) at 1 year were similarly within normal limits in both patients with exercise limitations and those without such limitations.CONCLUSIONS: Almost half of patients with PE have exercise limitation at 1 year that adversely influences HRQoL, dyspnea, and walking distance. CPET or 6MWD testing at 1 month may help to identify patients with a higher risk of exercise limitation at 1 year after PE. Based on our results, we believe that the deconditioning that occurs after acute PE could underlie this exercise limitation, but we cannot exclude the fact that this may have been present before PE.

Background We aimed to determine the frequency and predictors of exercise limitation after pulmonary embolism (PE) and to assess its association with health-related quality of life (HRQoL) and dyspnea. Methods One hundred patients with acute PE were recruited at five Canadian hospitals from 2010 to 2013. Cardiopulmonary exercise testing (CPET) was performed at 1 and 12 months. Quality of life (QoL), dyspnea, 6-min walk distance (6MWD), residual clot burden (perfusion scan, CT pulmonary angiography), cardiac function (echocardiography), and pulmonary function tests (PFTs) were measured during follow-up. The prespecified primary outcome was percent predicted peak oxygen uptake (Vo2 peak) < 80% at 1-year CPET. Results At 1 year, 40 of 86 patients (46.5%) had percent predicted Vo2 peak < 80% on CPET, which was associated with significantly worse generic health-related QoL (HRQoL), PE-specific HRQoL and dyspnea scores, and significantly reduced 6MWD at 1 year. Predictors of the primary outcome included male sex (relative risk [RR], 3.2; 95% CI, 1.3-8.1), age (RR, 0.98; 95% CI, 0.96-0.99 per 1-year age increase), BMI (RR 1.1; 95% CI, 1.01-1.2 per 1 kg/m2 BMI increase), and smoking history (RR, 1.8; 95% CI, 1.1-2.9), as well as percent predicted Vo2 peak < 80% on CPET at 1 month (RR, 3.8; 95% CI,1.9-7.2), and 6MWD at 1 month (RR, 0.82; 95% CI, 0.7-0.9 per 30-m increased walking distance). Baseline or residual clot burden was not associated with the primary outcome. Mean PFT and echocardiographic results (pulmonary artery pressure, right and left ventricular systolic function) at 1 year were similarly within normal limits in both patients with exercise limitations and those without such limitations. Conclusions Almost half of patients with PE have exercise limitation at 1 year that adversely influences HRQoL, dyspnea, and walking distance. CPET or 6MWD testing at 1 month may help to identify patients with a higher risk of exercise limitation at 1 year after PE. Based on our results, we believe that the deconditioning that occurs after acute PE could underlie this exercise limitation, but we cannot exclude the fact that this may have been present before PE. Trial Registry ClinicalTrials.gov; No.: NCT01174628; URL: www.clinicaltrials.gov.

The aim of this pictorial essay was to highlight the usefulness of fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in evaluating incidental infection or inflammation in cancer patients, related to surgical management. A retrospective review of 10,985 consecutive oncologic PET/CTs was done, and nine cases with suspected FDG positive infectious or inflammatory processes were selected for further review. PET/CT helped identify infections and inflammatory processes related to surgical management of cancer patients, define the extent of infection or inflammation, guide the management and, in some cases, evaluate response to therapy.

OBJECTIVE:The purpose of this article is to illustrate a wide spectrum of malignant primary and secondary pleural and pericardial diseases imaged with (18)F-FDG PET/CT.CONCLUSION:A wide variety of malignant pleural and pericardial diseases can be detected, staged, and monitored by FDG PET/CT. Although the PET/CT findings are often nonspecific, the aim of this atlas is to show that the spectrum of pleural and pericardial disease that can be evaluated with PET/CT is much broader than current literature would suggest. PET/CT readers and oncologists should be aware of the wide variety of malignancies that can affect the pleura and pericardium and some of the patterns of FDG uptake that can be observed in these cases.

A wide variety of malignant renal and urinary bladder diseases can be detected on (18)F-FDG PET/CT. Although the PET/CT findings are often nonspecific, the aim of this atlas was to demonstrate that the spectrum of renal and urinary bladder malignancy that can be evaluated with PET/CT is much broader than current medical literature would suggest. PET/CT readers and oncologists should be aware of the variety of urological tumor types that can be detected on PET/CT and some of the patterns of (18)F-FDG uptake that can be observed in these cases.

Xerostomia is a significant morbidity of radiation treatment in the management of head and neck cancers. To preserve salivary function, a surgical technique has been developed that involves the transfer of one submandibular gland to the ipsilateral submental space, where it can be shielded during radiation therapy. F-18 FDG PET/CT imaging characteristics of recently or remotely transferred submandibular glands have not been previously described in the literature. We report 2 cases of patients with surgically transferred submandibular glands, which highlight a potential pitfall in the interpretation of PET/CT of the head and neck region in oncologic patients.

Necrotic pseudotumor is a complication of metal-on-metal arthroplasty that has been reported with increasing frequency in the last 5 years. It is believed to be the result of a hypersensitivity reaction to metal ions such as nickel, cobalt, or chromium that are released in large quantities from these prostheses. The imaging appearance of a necrotic pseudotumor caused by a metal-on-metal prosthesis, on (18)F-FDG PET/CT or (99m)Tc-MDP bone scan has not been previously described in the literature. Our case demonstrates that a necrotic pseudotumor can be detected incidentally in oncologic patients referred for an (18)F-FDG PET/CT or a (99m)Tc-MDP bone scan, and recognizing this process is vital in preventing further tissue necrosis and patient morbidity, as the offending prosthesis must be promptly removed. The imaging characteristics of a necrotic pseudotumor on PET/CT and bone scan may also mimic a malignant process such as a necrotic sarcoma, and can represent a potential pitfall leading to a false positive diagnosis in an oncologic patient.

Diaphragmatic hernias are characterized by defects in the diaphragm that allow herniation of abdominal contents into the thorax. Herniation through the retrosternal foramen of Morgagni is rare, with less than 300 adult cases reported in the literature. This is a case of a 90-year-old woman who was diagnosed with herniation of the liver through the foramen of Morgagni on F-18 FDG PET/CT scan, which was done for the evaluation of a lung mass. Herniation of liver through the foramen of Morgagni is a potential pitfall in oncologic F-18 FDG PET/CT imaging, as it may mimic any FDG-avid anterior mediastinal mass, benign or malignant, especially in the presence of significant respiratory artifacts that commonly degrade image quality at the lung bases.

Diaphragmatic hernias are characterized by defects in the diaphragm that allow herniation of abdominal contents into the thorax. Herniation through the retrosternal foramen of Morgagni is rare, with less than 300 adult cases reported in the literature. This is a case of a 90-year-old woman who was diagnosed with herniation of the liver through the foramen of Morgagni on F-18 FDG PET/CT scan, which was done for the evaluation of a lung mass. Herniation of liver through the foramen of Morgagni is a potential pitfall in oncologic F-18 FDG PET/CT imaging, as it may mimic any FDG-avid anterior mediastinal mass, benign or malignant, especially in the presence of significant respiratory artifacts that commonly degrade image quality at the lung bases.

Xerostomia is a significant morbidity of radiation treatment in the management of head and neck cancers. To preserve salivary function, a surgical technique has been developed that involves the transfer of one submandibular gland to the ipsilateral submental space, where it can be shielded during radiation therapy. F-18 FDG PET/CT imaging characteristics of recently or remotely transferred submandibular glands have not been previously described in the literature. We report 2 cases of patients with surgically transferred submandibular glands, which highlight a potential pitfall in the interpretation of PET/CT of the head and neck region in oncologic patients.

About one-third of patients with Crohn disease develop intra-abdominal fistulas, and of these, cholecystocolic fistulas are among the rarest. F-18 FDG PET/CT can detect a vast variety of fistulas, although most are discovered incidentally. We present a very unusual case of a 79-year-old woman referred for an F-18 FDG PET/CT for evaluation of a solitary pulmonary nodule. A colon mass was detected incidentally that appeared to directly invade the gallbladder; however, histologic evaluation after surgery revealed a colon adenocarcinoma, with an adjacent cholecystocolic fistula arising from a transmural fissure ulcer in a nonneoplastic colon segment consistent with clinically silent Crohn disease.

Mycobacterium simiae (M. simiae) is an opportunistic pathogen rarely associated with human disease, although in recent years M. simiae has been detected with increasing frequency in human immunodeficiency virus (HIV)-infected patients, usually causing disseminated infection with fever, diarrhea and weight loss. We report the case of an HIV-positive man, who was referred for an (18)F-FDG PET/CT to evaluate a solitary pulmonary nodule. The PET/CT showed incidental large necrotic cervical lymph nodes, compatible with necrotizing cervical lymphadenitis. Biopsy and culture of one of the affected lymph nodes were positive for M. simiae. We present the first report of (18)F-FDG PET/CT imaging of an infectious process caused by M. simiae in humans.

OBJECTIVE FDG PET studies frequently use the liver as an internal reference organ to assess the significance of FDG uptake in pathologic processes involving other organs. The purpose of this study was to assess whether hepatic steatosis has a significant effect on the standardized uptake value (SUV) of the liver. SUBJECTS AND METHODS This prospective case-control study analyzed FDG PET/CT scans of patients with frank hepatic steatosis on the unenhanced CT portion of the study. Maximum SUVs (corrected for both body weight [SUV(bw)] and lean body mass [SUV(lbm)]) in 37 patients with hepatic steatosis were compared with those in 37 control patients without hepatic steatosis. RESULTS Patients with hepatic steatosis had statistically significant smaller mean (± SD) values than did the control subjects for liver SUV(lbm) (1.91 ± 0.57 vs 2.17 ± 0.36), liver SUV(lbm)-mediastinum ratio (1.23 ± 0.19 vs 1.35 ± 0.19), and liver SUV(bw)-mediastinum ratio (1.24 ± 0.16 vs 1.39 ± 0.22). CONCLUSION Hepatic steatosis results in a small statistically significant decrease in hepatic metabolic activity, as measured by FDG PET. However, because the degree of change is small, compared with healthy control subjects, this decrease is unlikely to have any clinical significance on the use of the liver as an internal reference organ.

A 52-year-old man had a positron emission tomography computed tomography (PET-CT) scan for staging of a biopsy proven lung adenocarcinoma. An additional acquisition of the lower extremities was performed as the patient complained of bilateral leg pain. The PET-CT scan showed a 6.5 X 5.0 cm left upper lobe lung mass invading the mediastinum with maximal standardized uptake value of 10.7, compatible with primary lung cancer. The CT portion of the PET-CT of the legs showed extensive irregular bilateral periosteal new bone formation in the long bones. The PET images showed diffuse moderately increased FDG uptake in the periostea of the long bones of the legs, with some focal sites of more intense FDG uptake in the thicker portions of the periosteum. A bone scan showed mild hyperemia surrounding the long bones of the legs and intense Tc-99m MDP uptake in the periostea. The patient was diagnosed with hypertrophic pulmonary osteoarthropathy.

A 52-year-old man had a positron emission tomography computed tomography (PET-CT) scan for staging of a biopsy proven lung adenocarcinoma. An additional acquisition of the lower extremities was performed as the patient complained of bilateral leg pain. The PET-CT scan showed a 6.5 x 5.0 cm left upper lobe lung mass invading the mediastinum with maximal standardized uptake value of 10.7, compatible with primary lung cancer. The CT portion of the PET-CT of the legs showed extensive irregular bilateral periosteal new bone formation in the long bones. The PET images showed diffuse moderately increased FDG uptake in the periostea of the long bones of the legs, with some focal sites of more intense FDG uptake in the thicker portions of the periosteum. A bone scan showed mild hyperemia surrounding the long bones of the legs and intense Tc-99m MDP uptake in the periostea. The patient was diagnosed with hypertrophic pulmonary osteoarthropathy.

A 72-year-old female patient had severe pulmonary hypertension on transthoracic echocardiography with a pulmonary arterial pressure of 125 mm Hg, moderate tricuspid regurgitation, and a moderately dilated, mildly hypokinetic right ventricle (RV). A CT scan, performed to assess the etiology of the pulmonary hypertension, revealed a right middle lobe lung nodule and enlarged mediastinal lymph nodes. A subsequent F-18 FDG PET scan demonstrated the right middle lobe lung nodule and the mediastinal adenopathy to be FDG-avid, but a striking incidental finding on this study was intense RV FDG uptake, secondary to RV hypertrophy and strain.