Mediastinal Masses in Nuclear Medicine Studies: A Diagnostic Algorithm.

There are multiple reasons for an anterior mediastinal mass. In this case, we discuss possible etiologies and offer an algorithm to narrow the differential diagnosis. When the mass cannot be diagnosed radiographically, the next step in imaging is a physiologic assessment with radionuclide modalities.

Optimizing 18F-FDG Uptake Time Before Imaging Improves the Accuracy of PET/CT in Liver Lesions.

Unlabelled: (18)F-FDG PET/CT has emerged as one of the fastest-growing imaging modalities. A shorter protocol results in a lower target-to-background ratio, which can increase the challenge of identifying mildly (18)F-FDG-avid lesions and differentiating inflammatory or physiologic activity from malignant activity. The purpose of this study was to determine the delay between radiotracer injection and imaging that optimizes target-to-background ratio while maintaining counts high enough to ensure scan sensitivity.

The Evaluation of Cardiac Sarcoidosis with 18F-FDG PET.

Cardiac involvement in sarcoidosis is associated with poor prognosis. (18)F-FDG PET can detect the presence of cardiac sarcoidosis, assess disease activity, and serve as a means to monitor treatment response in patients with cardiac sarcoidosis.

Use of SPECT/CT with 99mTc-MDP Bone Scintigraphy to Diagnose Symptomatic Os Acromiale.

Os acromiale is an anatomic variant that in rare cases can cause pain. (99m)Tc-methylene diphosphonate bone scintigraphy with SPECT/CT can play an important role in diagnosing this clinical entity. We present a male football player with shoulder pain secondary to a symptomatic os acromiale, and we demonstrate the findings on bone scanning with limited SPECT/CT that diagnosed this important clinical abnormality.

Implications of unexpected diffuse lung uptake on a 99mTc-sestimibi parathyroid scan.

Diffuse (99m)Tc-sestimibi uptake in the lungs is a sign of serious pathology and merits further work-up. We present a case in which diffuse lung uptake was incidentally found on a parathyroid scan.

Time sensitivity-corrected retention index: an enhanced metabolic index from 18F-FDG PET to differentiate between benign and malignant pulmonary nodules.

The aim of the study was to evaluate pulmonary nodules (PNs) by incorporating time sensitivity (S) factor in the retention index (RI) and compare with the traditional fixed interval method. After obtaining approval from the Human Investigations Committee, 97 PNs from 81 patients (age=70±11) referred for dual-time fluorine-18 fluorodeoxyglucose PET (16.1±1.

The appearance of congenitally corrected transposition of the great arteries on myocardial perfusion imaging.

We present a case of incidentally discovered congenitally corrected transposition of the great arteries (ccTGA), initially seen on stress-rest myocardial perfusion imaging (MPI). ccTGA has a characteristic appearance on MPI, which reflects the functional alterations associated with this condition.

Implications of Ambient Glucose Variation on the Target-to-Background Ratio of Hepatic Tumors By (18)FDG-PET Imaging.

Objectives: To investigate the effects of ambient glucose on quantitative analysis of hepatic tumors on 2-deoxy-2-((18)F)-fluoro-D-glucose ((18)FDG) positron emission tomography (PET) and to establish a method for glucose correction.

Patients And Methods: Eighty-six patients with hepatic lesions identified on (18)FDG PET/computed tomography (CT) were analyzed. The serum glucose level (Glc) was recorded prior to imaging, and the maximum standardized uptake value (SUV) in the hepatic tumors and the average SUV in normal liver were determined.

Complementary role of 18F-FDG PET and 123I-ioflupane SPECT in the diagnosis of Lewy body disease.

We present a case demonstrating how correlative imaging with (123)I-ioflupane SPECT and (18)F-FDG PET can be used to help make the diagnosis of Lewy body disease more specific.

Atypical Presentation of Sarcoidosis on ¹⁸F-FDG PET/CT.

On (18)F-FDG PET, inflammatory processes can be one of the most confounding factors for interpretation, particularly when the presentation of the process is atypical, as it was in the case of sarcoidosis reported here. Clinicians should be aware that sarcoidosis may mimic lung malignancies and lymphomas, regardless of typical or atypical appearance on (18)F-FDG PET.

Painful knee arthroplasty.

A triple-tracer nuclear medicine study that incorporates (99m)Tc-sulfur colloid, (111)In-labeled leukocytes, and (99m)Tc-methylene diphosphonate can be useful for the diagnosis of aseptic loosening in a patient after total-knee arthroplasty, as demonstrated in this case study. The triple-tracer technique takes less time and is more accurate than a bone scan alone.

Radiation therapy-induced phrenic neuropathy mimicking metastasis to the diaphragmatic crus on ¹⁸F-FDG PET/CT.

Benign unilateral uptake in the diaphragmatic crus is a relatively uncommon finding on (18)F-FDG PET/CT that can mimic the appearance of malignancy in patients with known cancer, as illustrated in this patient with neuroendocrine carcinoma. It is important for the PET interpreter to recognize this finding and attribute it to benign uptake based on the patient's history and symptoms at the time of the scan. Correlation with the findings of other available imaging modalities is also important to characterize focal uptake in unusual locations.

Radiographically Occult Latent Radiogenic Osteosarcoma Uncovered on Tc-99m Methylene-diphosphonate Bone Scintigraphy.

We present a case of a 70-year-old male who was referred for a technetium-99m methylene-diphosphonate bone scan for mild left hip pain and an elevated alkaline phosphatase level of 770 units/L. No additional information was provided and the patient's history was limited due to a language barrier. We were able to ascertain that the patient had a remote history of prostate cancer, which had been treated with radiation.

The role of scintigraphy in confirmation of suspected brain death.

We present a case illustrating how cerebral perfusion scintigraphy can be used to assist in crucial medical decision making in the intensive care setting for patients who are maintained on life support but are clinically suspected to have brain death. Cerebral perfusion scintigraphy can confirm brain death but cannot be used to diagnose it. (99m)Tc-HMPAO and (99m)Tc-ethylcysteinate dimer are the preferred imaging agents since they cross the blood-brain barrier.

Improvement of hepatic lesion characterization by 18F-FDG PET/CT with the use of the lesion to background liver activity ratio.

Objective: This study aimed to develop a reproducible method to improve (18)F-FDG PET/CT's diagnostic accuracy when characterizing hepatic lesions.

Methods: This was a retrospective study of 76 patients with various types of cancer who had 134 liver lesions described on diagnostic CT, MRI, or (18)F-FDG PET/CT. All 134 lesions were imaged by PET/CT.

Semantic Dementia Diagnosed by F-18 FDG PET/MRI: Co-registered Images.

We report a case of a 61-year-old male who presented with a sudden change in mental status. From a psychiatric standpoint, his symptoms were consistent with a bipolar disorder. A neurology consult raised suspicion for vascular dementia, given the sudden onset of symptoms; however, the magnetic resonance angiography (MRA) was unremarkable.

Neurocysticercosis on 18F-FDG PET/MRI: co-registered Images.

This is a case of a 32-year-old female patient who presented with new onset partial complex seizures. MRI of the brain demonstrated a suspicious ring-enhancing lesion in the right temporal lobe. This finding was felt to be a primary brain malignancy or less likely an infectious process.

Application of heat-damaged Tc-99m RBCs in a patient with suspected hepatic metastasis.

We present a patient with a remote history of splenectomy and recent hemicolectomy for colon adenocarcinoma. On routine surveillance chest/abdomen/pelvis CT, a lesion suspicious for hepatic metastasis was identified. Followup MRI was inconclusive.

Hepatocellular carcinoma: response to TACE assessed with semiautomated volumetric and functional analysis of diffusion-weighted and contrast-enhanced MR imaging data.

Purpose: To determine the association of early changes in posttreatment apparent diffusion coefficient (ADC) and venous enhancement (VE) with tumor size change after transarterial chemoembolization (TACE) by using an investigational semiautomated software.

Materials And Methods: This retrospective HIPAA-compliant study was approved by the institutional review board, with waiver of informed consent. Patients underwent magnetic resonance (MR) imaging at 1.