Fetal Dose from PET and CT in Pregnant Patients.

When pregnancy is discovered during or after a diagnostic examination, the physician or the patient may request an estimate of the radiation dose received by the fetus as per guidelines and standard operating procedures. This study provided the imaging community with dose estimates to the fetus from PET/CT with protocols that are adapted to University of Michigan low-dose protocols for patients known to be pregnant. Methods: There were 9 patients analyzed with data for the first, second, and third trimesters, the availability of which is quite rare. These images were used to calculate the size-specific dose estimate (SSDE) from the CT scan portion and the SUV and 18F-FDG uptake dose from the PET scan portion using the MIRD formulation. The fetal dose estimates were tested for correlation with each of the following independent measures: gestational age, fetal volume, average water-equivalent diameter of the patient along the length of the fetus, SSDE, SUV, and percentage of dose from 18F-FDG. Stepwise multiple linear regression analysis was performed to assess the partial correlation of each variable. To our knowledge, this was the first study to determine fetal doses from CT and PET images. Results: Fetal self-doses from 18F for the first, second, and third trimesters were 2.18 mGy (single data point), 0.74-1.82 mGy, and 0.017-0.0017 mGy, respectively. The combined SSDE and fetal self-dose ranged from 1.2 to 8.2 mGy. These types of images from pregnant patients are rare. Conclusion: Our data indicate that the fetal radiation exposure from 18F-FDG PET and CT performed, when medically necessary, on pregnant women with cancer is low. All efforts should be made to minimize fetal radiation exposure by modifying the protocol.

ACR Appropriateness Criteria® Chronic Chest Pain-High Probability of Coronary Artery Disease: 2021 Update.

Management of patients with chronic chest pain in the setting of high probability of coronary artery disease (CAD) relies heavily on imaging for determining or excluding presence and severity of myocardial ischemia, hibernation, scarring, and/or the presence, site, and severity of obstructive coronary lesions, as well as course of management and long-term prognosis. In patients with no known ischemic heart disease, imaging is valuable in determining and documenting the presence, extent, and severity of obstructive coronary narrowing and presence of myocardial ischemia. In patients with known ischemic heart disease, imaging findings are important in determining the management of patients with chronic myocardial ischemia and can serve as a decision-making tool for medical therapy, angioplasty, stenting, or surgery. This document summarizes the recent growing body of evidence on various imaging tests and makes recommendations for imaging based on the available data and expert opinion. This document is focused on epicardial CAD and does not discuss the microvascular disease as the cause for CAD. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR-ACNM-ASTRO-SNMMI Practice Parameter for Lutetium-177 (Lu-177) DOTATATE Therapy.

OBJECTIVES: This practice parameter (PP) for Lutetium-177 (Lu-177) DOTATATE peptide receptor radionuclide therapy (PRRT) aims to guide authorized users in selection of appropriate adult candidates with gastroeneropancreatic neuroendocrine tumors (GEP-NETs) from foregut, midgut, and hindgut. The essential selection criteria include somatostatin receptor-positive GEP-NETs, which are usually inoperable and progressed despite standard therapy. Lu-177 DOTATATE is a radiopharmaceutical with high avidity for somatostatin receptors that are overexpressed by these tumors. This document ensures safe handling of Lu-177 DOTATATE by the authorized users and safe management of affected patients. METHODS: The document was developed according to the systematic process developed by the American College of Radiology (ACR) and described on the ACR Web site (https://www.acr.org/Clinical-Resources/Practice-Parameters-and-Technical-Standards). The PP development was led by 2 ACR Committees on Practice Parameters (Nuclear Medicine and Molecular Imaging and Radiation Oncology) collaboratively with the American College of Nuclear Medicine, American Society of Radiation Oncology, and Society of Nuclear Medicine and Molecular Imaging. RESULTS: The Lu-177 DOTATATE PP reviewed pharmacology, indications, adverse effects, personnel qualifications, and required clinical evaluation before starting the treatment, as well as the recommended posttherapy monitoring, quality assurance, documentation, and appropriate radiation safety instructions provided in written form and explained to the patients. CONCLUSIONS: Lu-177 DOTATATE is available for therapy of inoperable and/or advanced GEP-NETs when conventional therapy had failed. It can reduce tumor size, improve symptoms, and increase the progression free survival. The PP document provides clinical guidance for authorized users to assure an appropriate, consistent, and safe practice of Lu-177 DOTATATE.

ACR-ACNM-ASTRO-SNMMI Practice Parameter for Lutetium-177 (Lu-177) DOTATATE Therapy.

OBJECTIVES: This practice parameter (PP) for Lutetium-177 (Lu-177) DOTATATE peptide receptor radionuclide therapy (PRRT) aims to guide authorized users in selection of appropriate adult candidates with gastroeneropancreatic neuroendocrine tumors (GEP-NETs) from foregut, midgut, and hindgut. The essential selection criteria include somatostatin receptor-positive GEP-NETs, which are usually inoperable and progressed despite standard therapy. Lu-177 DOTATATE is a radiopharmaceutical with high avidity for somatostatin receptors that are overexpressed by these tumors. This document ensures safe handling of Lu-177 DOTATATE by the authorized users and safe management of affected patients. METHODS: The document was developed according to the systematic process developed by the American College of Radiology (ACR) and described on the ACR Web site (https://www.acr.org/Clinical-Resources/Practice-Parameters-and-Technical-Standards). The PP development was led by 2 ACR Committees on Practice Parameters (Nuclear Medicine and Molecular Imaging and Radiation Oncology) collaboratively with the American College of Nuclear Medicine, American Society of Radiation Oncology, and Society of Nuclear Medicine and Molecular Imaging. RESULTS: The Lu-177 DOTATATE PP reviewed pharmacology, indications, adverse effects, personnel qualifications, and required clinical evaluation before starting the treatment, as well as the recommended posttherapy monitoring, quality assurance, documentation, and appropriate radiation safety instructions provided in written form and explained to the patients. CONCLUSIONS: Lu-177 DOTATATE is available for therapy of inoperable and/or advanced GEP-NETs when conventional therapy had failed. It can reduce tumor size, improve symptoms, and increase the progression free survival. The PP document provides clinical guidance for authorized users to assure an appropriate, consistent, and safe practice of Lu-177 DOTATATE.

An Unusual Presentation of Breast Implant Rupture.

ABSTRACT: A 99mTc-methylene diphosphate (MDP) bone scintigraphy scan was performed to follow up metastatic breast cancer. A circular region of radiotracer uptake in the location of the patient's left breast implant was seen. Review of the same-day chest CT and the prior CT showed that the patient's breast implant had ruptured in the interim. The 99mTc-MDP uptake in the capsule of the breast implant was attributed to rupture, likely secondary to inflammation. This is an example of an unusual presentation of breast implant rupture discovered on a 99mTc-MDP bone scintigraphy scan.

ACR-ACNM-ASTRO-SNMMI Practice Parameter for the Performance of Therapy With Radium-223.

AIM/OBJECTIVES/BACKGROUND: The goal of therapy with unsealed radiopharmaceutical sources is to provide either cure or significant prolongation of disease-specific survival, and effective reduction and/or prevention of adverse disease-related symptoms or untoward events while minimizing treatment-associated side effects and complications. Radium-223 dichloride (radium-223) is an alpha particle-emitting isotope used for targeted bone therapy. This practice parameter is intended to guide appropriately trained and licensed physicians performing therapy with radium-223. Such therapy requires close cooperation and communication between the physicians who are responsible for the clinical management of the patient and those who administer radiopharmaceutical therapy and manage the attendant side effects. Adherence to this parameter should help to maximize the efficacious use of radium-223, maintain safe conditions, and ensure compliance with applicable regulations. METHODS: This practice parameter was developed according to the process described on the American College of Radiology (ACR) website ("The Process for Developing ACR Practice Parameters and Technical Standards," www.acr.org/ClinicalResources/Practice-Parameters-and-Technical-Standards) by the Committee on Practice Parameters of the ACR Commission on Radiation Oncology in collaboration with the American College of Nuclear Medicine (ACNM), the American Society for Radiation Oncology (ASTRO), and the Society of Nuclear Medicine and Molecular Imaging (SNMMI). All these societies contributed to the development of the practice parameter and approved the final document. RESULTS: This practice parameter addresses the many factors which contribute to appropriate, safe, and effective clinical use of radium-223. Topics addressed include qualifications and responsibilities of personnel, specifications of patient examination and treatment; documentation, radiation safety, quality control/improvement, infection control, and patient education. CONCLUSIONS: This practice parameter is intended as a tool to guide clinical use of radium-223 with the goal of facilitating safe and effective medical care based on current knowledge, available resources and patient needs. The sole purpose of this document is to assist practitioners in achieving this objective.

Management of Incidental Breast Lesions Detected at Nuclear Medicine Examinations.

Nuclear medicine studies are often performed in patients with breast cancer; however, incidental radiotracer uptake in the breasts can be observed in patients with nonbreast malignancies. Benign and malignant lesions can be identified on planar, SPECT, and PET scans. This review will outline the molecular and radiographic imaging appearance of benign and malignant breast lesions on sestamibi scans, bone scans, radioiodine studies, as well as PET studies using fluorine 18 (18F) fluorodeoxyglucose, gallium 68 (68Ga) tetraazacyclododecane tetraacetic acid octreotate (or DOTATATE), 68Ga prostate-specific membrane antigen, and 18F-fluciclovine radiotracers. Recognizing these lesions at molecular and anatomic imaging is important to ensure accurate diagnosis and appropriate management. Keywords: Breast, Mammography, Molecular Imaging, PET/CT, Radionuclide Studies, SPECT/CT © RSNA, 2020.

Do Deauville Scores Improve the Clinical Utility of End-of-Therapy FDG PET Scans for Pediatric Hodgkin Lymphoma?

OBJECTIVE: The purpose of this study was to evaluate the clinical utility of Deauville scores in interpretation of end-of-chemotherapy FDG PET scans. CONCLUSION: Deauville scores improve the clinical utility of end-of-chemotherapy PET, as evidenced by an increase in positive predictive value to 72.7% from 44.4% on the basis of report alone. The negative predictive value remains greater than 95%.

Management of Diabetes Mellitus Before 18F-Fluorodeoxyglucose PET/CT: A Nationwide Patient-Centered Assessment of Approaches to Examination Preparation.

PURPOSE: The aim of this study was to perform, from the patient's point of view, a nationwide assessment of nuclear medicine practices regarding diabetic management before 18F-fluorodeoxyglucose (FDG) PET/CT for oncologic indications. METHODS: This prospective observational study was exempt from institutional review board oversight. Sixty-five nuclear medicine scheduling lines (33 academic, 32 private practice, 12-17 in each of the five US regions) were called using a prewritten script under the guise of a nonexpert patient's family member about scheduling a patient with diabetes with "cancer" for FDG PET/CT. Each center was called three times on three different days. The following data were collected: (1) blood glucose threshold for rescheduling an examination, (2) when or if to stop various medications, (3) fasting requirements, and (4) time-of-day scheduling preferences. Withheld information was not specifically requested. Descriptive statistics were calculated. RESULTS: There were 195 phone calls (mean duration, 2.9 min; range, 2-6 min). Relevant information was often withheld; withholding rates were as follows: blood glucose threshold, 71% (138 of 195); short-acting insulin instructions, 30% (59 of 195); long-acting insulin instructions, 99% (193 of 195); metformin instructions, 88% (179 of 195); fasting duration, 37% (72 of 195); and time-of-day scheduling preference, 91% (177 of 195). Mean provided data were as follows: blood glucose threshold, 195 mg/dL (range, 150-210 mg/dL); short-acting insulin withholding, 4.9 hours (range, 4-8 hours); long-acting insulin withholding, 12 hours (range, 12-24 hours); fasting duration, 5 hours (range, 4-8 hours); and preferred examination time, 91% (177 of 195). When specified (n = 18), morning scheduling was preferred (8% [15 of 195] versus 2% [3 of 195]). CONCLUSIONS: Diabetes-specific information is commonly withheld by nuclear medicine call centers throughout the United States when discussing oncologic FDG PET/CT despite local and national policies indicating its importance.

Positron Emission Tomography 18F-Fluorodeoxyglucose Uptake Correlates with KRAS and EMT Gene Signatures in Operable Esophageal Adenocarcinoma.

BACKGROUND: 18F-fluorodeoxyglucose positron emission tomography is an imaging modality critical to the diagnosis and staging of esophageal cancer. Despite this, the genetic abnormalities associated with increased 18F-fluorodeoxyglucose (FDG)-maximum standardized uptake value (SUVmax) have not been previously explored in esophageal adenocarcinoma. MATERIALS AND METHODS: Treatment-naïve patients, for whom frozen tissue and 18F-fluorodeoxyglucose positron emission tomography data were available, undergoing esophagectomy from 2003 to 2012, were identified. Primary tumor FDG-uptake (SUVmax) was quantified as low (<5), moderate, or high (>10). Genome-wide expression analyses (e.g., microarray) were used to examine gene expression differences associated with FDG-uptake. RESULTS: Eighteen patients with stored positron emission tomography data and tissue were reviewed. Overall survival was similar between patients with high (n = 9) and low (n = 6) FDG-uptake tumors (P = 0.71). Differences in gene expression between tumors with high and low FDG-uptake included enriched expression of various matrix metalloproteinases, extracellular-matrix components, oncogenic signaling members, and PD-L1 (fold-change>2.0, P < 0.05) among the high-FDG tumors. Glycolytic gene expression and pathway involvement were similar between the high- and low-FDG tumor subsets (P = 0.126). Gene ontology analysis of the most differentially expressed genes demonstrated significant upregulation of gene sets associated with extracellular matrix organization and vascular development (P < 0.005). Gene set enrichment analysis further demonstrated associations between FDG-uptake intensity and canonical oncogenic processes, including hypoxia, angiogenesis, KRAS signaling, and epithelial-to-mesenchymal transition (P < 0.001). Interestingly, KRAS expression did not predict worse survival in a larger cohort (n = 104) of esophageal adenocarcinomas (P = 0.64). CONCLUSIONS: These results suggest that elevated FDG-uptake is associated with a variety of oncogenic alterations in operable esophageal adenocarcinoma. These pathways present potential therapeutic targets among tumors exhibiting high FDG-uptake.

18F-FDG PET intensity correlates with a hypoxic gene signature and other oncogenic abnormalities in operable non-small cell lung cancer.

BACKGROUND: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is critical for staging non-small-cell lung cancer (NSCLC). While PET intensity carries prognostic significance, the genetic abnormalities associated with increased intensity remain unspecified. METHODS: NSCLC samples (N = 34) from 1999 to 2011 for which PET data were available were identified from a prospectively collected tumor bank. PET intensity was classified as mild, moderate, or intense based on SUVmax measurement or radiology report. Associations between genome-wide expression (RNAseq) and PET intensity were determined. Associations with overall survival were then validated in two external NSCLC cohorts. RESULTS: Overall survival was significantly worse in patients with PET-intense (N = 11) versus mild (N = 10) tumors (p = 0.039). Glycolytic gene expression patterns were markedly similar between intense and mild tumors. Gene ontology analysis demonstrated significant enhancement of cell-cycle and proliferative processes in FDG-intense tumors (p<0.001). Gene set enrichment analysis (GSEA) suggested associations between PET-intensity and canonical oncogenic signaling pathways including MYC, NF-κB, and HIF-1. Using an external cohort of 25 tumors with PET and genomic profiling data, common genes and gene sets were validated for additional study (P<0.05). Of these common gene sets, 20% were associated with hypoxia or HIF-1 signaling. While HIF-1 expression did not correlate with poor survival in the NSCLC validation cohort (N = 442), established targets of hypoxia signaling (PLAUR, ADM, CA9) were significantly associated with poor overall survival. CONCLUSIONS: PET-intensity is associated with a variety of oncogenic alterations in operable NSCLC. Adjuvant targeting of these pathways may improve survival among patients with PET-intense tumors.

ACR Appropriateness Criteria® Imaging for Transcatheter Aortic Valve Replacement.

Aortic stenosis is a common valvular condition with increasing prevalence in aging populations. When severe and symptomatic, the downstream prognosis is poor without surgical or transcatheter aortic valve replacement. Transcatheter aortic valve replacement is now considered a viable alternative to surgical aortic valve replacement in patients considered high and intermediate risk for surgery. Pre-intervention imaging with echocardiography and CT are essential for procedure planning and device selection to help optimize clinical outcomes with MR angiography playing largely a complementary role. Modern 3-D cross-sectional imaging has consistently shown to help reduce procedural complications from vascular access injury to paravalvular regurgitation and coronary obstruction. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Chronic Chest Pain-High Probability of Coronary Artery Disease.

In patients with chronic chest pain in the setting of high probability of coronary artery disease (CAD), imaging has major and diverse roles. First, imaging is valuable in determining and documenting the presence, extent, and severity of myocardial ischemia, hibernation, scarring, and/or the presence, site, and severity of obstructive coronary lesions. Second, imaging findings are important in determining the course of management of patients with suspected chronic myocardial ischemia and better defining those patients best suited for medical therapy, angioplasty/stenting, or surgery. Third, imaging is also necessary to determine the long-term prognosis and likely benefit from various therapeutic options by evaluating ventricular function, diastolic relaxation, and end-systolic volume. Imaging studies are also required to demonstrate other abnormalities, such as congenital/acquired coronary anomalies and severe left ventricular hypertrophy, that can produce angina in the absence of symptomatic coronary obstructive disease due to atherosclerosis. Clinical risk assessment is necessary to determine the pretest probability of CAD. Multiple methods are available to categorize patients as low, medium, or high risk for developing CAD. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

In-Person Communication Between Radiologists and Acute Care Surgeons Leads to Significant Alterations in Surgical Decision Making.

PURPOSE: The aim of this study was to determine if direct in-person communication between an acute care surgical team and radiologists alters surgical decision making. METHODS: Informed consent was waived for this institutional review board-exempt, HIPAA-compliant, prospective quality improvement study. From January 29, 2015 to December 10, 2015, semiweekly rounds lasting approximately 60 min were held between the on-call acute care surgery team (attending surgeon, chief resident, and residents) and one of three expert abdominal radiologists. A comprehensive imaging review was performed of recent and comparison examinations for cases selected by the surgeons in which medical and/or surgical decision making was pending. All reviewed examinations had available finalized reports known to the surgical team. RADPEER interradiologist concordance scores were assigned to all reviewed examinations. The impression and plan of the attending surgeon were recorded before and after each in-person review. RESULTS: One hundred patients were reviewed with 11 attending surgeons. The in-person meetings led to changes in surgeons' diagnostic impressions in 43% (43 of 100) and changes in medical and/or surgical planning in 43% (43 of 100; 20 acute changes, 23 nonacute changes, 19 changes in operative management) of cases. There were major discrepancies (RADPEER score ≥3) between the impression of the reviewing radiologist and the written report in 11% of cases (11 of 100). CONCLUSIONS: Targeted in-person collaboration between radiologists and acute care surgeons is associated with substantial and frequent changes in patient management, even when the original written report contains all necessary data. The primary mechanism seems to be promotion of a shared mental model that facilitates the exchange of complex information.

Cost-Savings Analysis of Renal Scintigraphy, Stratified by Renal Function Thresholds: Mercaptoacetyltriglycine Versus Diethylene Triamine Penta-Acetic Acid.

PURPOSE: To determine the financial implications of switching technetium (Tc)-99m mercaptoacetyltriglycine (MAG-3) to Tc-99m diethylene triamine penta-acetic acid (DTPA) at certain renal function thresholds before renal scintigraphy. METHODS: Institutional review board approval was obtained, and informed consent was waived for this HIPAA-compliant, retrospective, cohort study. Consecutive adult subjects (27 inpatients; 124 outpatients) who underwent MAG-3 renal scintigraphy, in the period from July 1, 2012 to June 30, 2013, were stratified retrospectively by hypothetical serum creatinine and estimated glomerular filtration rate (eGFR) thresholds, based on pre-procedure renal function. Thresholds were used to estimate the financial effects of using MAG-3 when renal function was at or worse than a given cutoff value, and DTPA otherwise. Cost analysis was performed with consideration of raw material and preparation costs, with radiotracer costs estimated by both vendor list pricing and proprietary institutional pricing. The primary outcome was a comparison of each hypothetical threshold to the clinical reality in which all subjects received MAG-3, and the results were supported by univariate sensitivity analysis. RESULTS: Annual cost savings by serum creatinine threshold were as follows (threshold given in mg/dL): $17,319 if ≥1.0; $33,015 if ≥1.5; and $35,180 if ≥2.0. Annual cost savings by eGFR threshold were as follows (threshold given in mL/min/1.73 m(2)): $21,649 if ≤60; $28,414 if ≤45; and $32,744 if ≤30. Cost-savings inflection points were approximately 1.25 mg/dL (serum creatinine) and 60 mL/min/1.73m(2) (eGFR). Secondary analysis by proprietary institutional pricing revealed similar trends, and cost savings of similar magnitude. Sensitivity analysis confirmed cost savings at all tested thresholds. CONCLUSIONS: Reserving MAG-3 utilization for patients who have impaired renal function can impart substantial annual cost savings to a radiology department.

Incidental radiologic findings at breast cancer diagnosis and likelihood of disease recurrence.

Despite guidelines recommending against its routine use, perioperative imaging for distant metastases is frequently performed in newly diagnosed breast cancer patients, uncovering incidental findings of uncertain significance. We assessed the clinical significance of incidental findings by determining if their presence is associated with disease recurrence. A retrospective review of staging imaging was performed in patients with stage II or III invasive breast cancer diagnosed during 2008-2009 at a large academic medical center. Data related to perioperative imaging and disease recurrence were abstracted from the medical record. Kaplan-Meier curves and Cox proportional hazards models were used to assess the association between incidental findings and time to disease recurrence. A total of 169 of 340 patients (49.7 %) underwent staging evaluation for distant metastases (CT chest, abdomen, pelvis, bone scan, and/or PET-CT). Of these, 146 (86.4 %) had at least one suspicious or indeterminate finding. Follow-up studies were performed in 73 (43.2 %) patients. Nineteen patients were diagnosed with metastatic disease at diagnosis, 18 of whom had stage III disease. In patients without metastatic disease at diagnosis, 32 later developed recurrence. Non-calcified pulmonary nodules were associated with shorter time to disease recurrence (hazard ratio 2.51, 95 % CI 1.13-5.57, p = 0.02). Imaging for distant metastases frequently reveals indeterminate findings, most of which are not associated with disease recurrence. The association between pulmonary nodules and recurrence warrants validation in an independent cohort. Overall, these findings support current guidelines recommending against routine extent of disease evaluation in patients with newly diagnosed stage II breast cancer.

Utility of (99m)Tc RBC Scintigraphy in Diagnosing Parotid Venous Malformations.

Venous malformations of the parotid glands are uncommon and can be difficult to confirm on routine anatomical imaging alone because of overlap of imaging features with other more common parotid lesions. (99m)Tc RBC scans combined with SPECT/CT offer a noninvasive way to diagnose parotid venous malformations without the need for biopsy. Combined with anatomical findings of phleboliths (when present), the diagnosis can be reliably determined. We present a case where MRI and biopsy were inconclusive, but the SPECT/CT was used to confirm the suspicion of a benign venous malformation.

Autoimmune limbic encephalitis detected on FDG brain scan performed for the evaluation of dementia.

Most diagnostic imagers are familiar with the classic patterns of altered metabolism seen in Alzheimer disease, frontal temporal dementia, and dementia with Lewy bodies. However, awareness of other conditions that can cause cognitive impairment is crucial when interpreting FDG brain PET studies. This is particularly true of infectious and inflammatory processes, such as viral encephalitis, which should be diagnosed and treated on an emergent basis. In addition, altered metabolism can be caused by autoimmune paraneoplastic and encephalitic syndromes. We report a case of autoimmune limbic encephalitis encountered as part of evaluation for atypical onset cognitive impairment.

Diffuse liver uptake on (99m)Tc-MDP bone scan secondary to severe hepatic failure.

Hepatic uptake on an MDP bone scan is a non-specific finding. When present, the etiology needs to be determined. The differential diagnosis depends on the pattern of uptake. Metastatic breast and colon cancer are frequent causes of focal faint uptake. Diffuse uptake is rare, but can be seen with hepatitis, amyloid, and IV gadolinium administration. In addition, aluminum breakthrough from the molybdenum generator can cause colloid formation and subsequent diffuse hepatic uptake. We present a case of diffuse uptake in a patient with acute hepatic failure. The etiology of the failure was extensive thrombosis of the inferior vena cava (IVC).