Mammography Screening Outreach Through Non-Primary Care-Based Services.

OBJECTIVE: To estimate the proportion of patients visiting urgent care centers or emergency departments or being hospitalized who were not up to date with recommended mammography screening to assess the potential impact of non-primary care-based cancer screening interventions. METHODS: Adult participants from the 2019 National Health Interview Survey were included. Among participants not up to date with breast cancer screening guidelines based on ACR recommendations, the proportion of patients reporting an urgent care, emergency department visit, or hospitalization within the last year was estimated accounting for complex survey sampling design features. Multiple variable logistic regression analyses were then conducted to evaluate the association between sociodemographic characteristics and mammography screening adherence. RESULTS: The study included 9,139 women between the ages of 40 and 74 years without history of breast cancer. Of these respondents, 44.9% did not report mammography screening within the last year. Among participants who did not report mammography screening, 29.2% reported visiting an urgent care center, 21.8% reported visiting an emergency room, and 9.6% reported being hospitalized within the last year. The majority of patients receiving non-primary care-based services, who were not up to date with mammography screening, were from historically underserved groups including Black and Hispanic patients. CONCLUSION: Nearly 10% to 30% of participants who have not obtained recommended breast cancer screening have visited non-primary care-based services including urgent care centers or emergency rooms or have been hospitalized within the last year.

Predictive Value of Coronary Artery Calcium in Patients Receiving Computed Tomography Pulmonary Angiography for Suspected Pulmonary Embolism in the Emergency Department.

PURPOSE: Coronary artery calcium (CAC) is a frequent incidental finding on computed tomography pulmonary angiogram (CTPA) in the evaluation of pulmonary embolism (PE) in the emergency department (ED); however, its prognostic value is unclear. In this study, we interrogate the prognostic value of CAC identified on CTPA in predicting adverse outcomes in the evaluation of PE in the ED. MATERIALS AND METHODS: In this retrospective cohort study, we identified 610 patients presenting to the ED in 2013 and evaluated with CTPA for suspected PE. Ordinal CAC scores were evaluated as absent (0), mild (1), moderate (2), or severe (3) in each of the 4 main coronary arteries. Composite CAC scores were subsequently compared against adverse clinical outcomes, defined as intensive care unit admission, hospital stay longer than 72 hours, or death during hospital course or at 6-month follow-up, using univariate and multivariate logistic regression analyses. Relevant exclusion criteria included a history of cardiovascular disease. RESULTS: In all, 365 patients met the inclusion criteria (231 women, mean age 56±16 y) with 132 patients (36%) having some degree of CAC and 16 (4%) having severe CAC. Known malignancy was present in 151 (41%) patients and composite adverse clinical outcomes were observed in 98 patients (32%). Age, presence of acute PE, malignancy, and presence of CAC were significant predictors of adverse outcomes on both univariate and multivariate analyses. CAC was not an independent predictor of short-term adverse outcomes on multivariate analysis ( P =0.06) when all patients were considered. However, when patients with known malignancy were excluded, CAC was an independent predictor of short-term adverse outcomes (odds ratio=2.5, confidence interval=1.1-5.5, P =0.03) independent of age and presence of PE. CONCLUSION: The presence of CAC on CT PA was predictive of adverse outcomes in patients without known cardiac disease presenting to the ED with suspected PE.

Imaging Manifestations of Chest Trauma.

Trauma is the leading cause of death among individuals under 40 years of age, and pulmonary trauma is common in high-impact injuries. Unlike most other organs, the lung is elastic and distensible, with a physiologic capacity to withstand significant changes in contour and volume. The most common types of lung parenchymal injury are contusions, lacerations, and hematomas, each having characteristic imaging appearances. A less common type of lung injury is herniation. Chest radiography is often the first-line imaging modality performed in the assessment of the acutely injured patient, although there are inherent limitations in the use of this modality in trauma. CT images are more accurate for the assessment of the nature and extent of pulmonary injury than the single-view anteroposterior chest radiograph that is typically obtained in the trauma bay. However, the primary limitations of CT concern the need to transport the patient to the CT scanner and a longer processing time. The American Association for the Surgery of Trauma has established the most widely used grading scale to describe lung injury, which serves to communicate severity, guide management, and provide useful prognostic factors in a systematic fashion. The authors provide an in-depth exploration of the most common types of pulmonary parenchymal, pleural, and airway injuries. Injury grading, patient management, and potential complications of pulmonary injury are also discussed. ©RSNA, 2021.

Therapy-Induced Evolution of Human Lung Cancer Revealed by Single-Cell RNA Sequencing.

Lung cancer, the leading cause of cancer mortality, exhibits heterogeneity that enables adaptability, limits therapeutic success, and remains incompletely understood. Single-cell RNA sequencing (scRNA-seq) of metastatic lung cancer was performed using 49 clinical biopsies obtained from 30 patients before and during targeted therapy. Over 20,000 cancer and tumor microenvironment (TME) single-cell profiles exposed a rich and dynamic tumor ecosystem. scRNA-seq of cancer cells illuminated targetable oncogenes beyond those detected clinically. Cancer cells surviving therapy as residual disease (RD) expressed an alveolar-regenerative cell signature suggesting a therapy-induced primitive cell-state transition, whereas those present at on-therapy progressive disease (PD) upregulated kynurenine, plasminogen, and gap-junction pathways. Active T-lymphocytes and decreased macrophages were present at RD and immunosuppressive cell states characterized PD. Biological features revealed by scRNA-seq were biomarkers of clinical outcomes in independent cohorts. This study highlights how therapy-induced adaptation of the multi-cellular ecosystem of metastatic cancer shapes clinical outcomes.

Dedicated Diagnostic Radiology/Radiation Oncology Rounds: Added Value Beyond Traditional Tumor Boards.

OBJECTIVES: We aimed to evaluate the impact of collaborative discussion between diagnostic radiologists and radiation oncologists on radiation oncology management for thoracic oncology patients. METHODS: We reviewed cases presented at multidisciplinary thoracic tumor boards (TTB) (n = 122) and diagnostic radiology/radiation oncology rounds (DR/ROR) (n = 45). Changes in planned radiation management following imaging discussion were categorized-no change, timing change, and treatment volume change. Phase of care was also classified. In DR/ROR, radiation oncologists were surveyed regarding (1) change in radiation oncology management and (2) change in confidence (both 5-point Likert scales). RESULTS: Discussion of imaging with a radiologist changed radiation oncology management in 31.1% of TTB cases and 68.9% of DR/ROR cases (P < 0.001). Changes to the timing of initiating radiation therapy occurred with similar frequency in the 2 settings (31.1% vs 46.7%, P = 0.063). Changes to target volume occurred more frequently in DR/ROR (35.6% vs <1%), P < 0.001. Over half of imaging discussions in DR/ROR resulted in at least "moderate" change in radiation oncology management, and the level of confidence held by the radiation oncologists increased following discussion with radiologists in 95.6% of cases. CONCLUSION: Collaborative discussions between radiation oncologists and diagnostic radiologists in a multispecialty tumor board and in targeted 2-specialty rounds are not redundant, but result in different management changes and at different phases of care. Our study emphasizes the importance of consultation with physicians as an area where radiologists can add value, specifically the added benefit of smaller collaborative discussions.

Integrated PET-MRI for Glioma Surveillance: Perfusion-Metabolism Discordance Rate and Association With Molecular Profiling.

OBJECTIVE: Both 18F-FDG PET and perfusion MRI are commonly used techniques for posttreatment glioma surveillance. Using integrated PET-MRI, we assessed the rate of discordance between simultaneously acquired FDG PET images and dynamic contrast-enhanced (DCE) perfusion MR images and determined whether tumor genetics predicts discordance. MATERIALS AND METHODS: Forty-one consecutive patients with high-grade gliomas (20 with grade IV gliomas and 21 with grade III gliomas) underwent a standardized tumor protocol performed using an integrated 3-T PET-MRI scanner. Quantitative measures of standardized uptake value, plasma volume, and permeability were obtained from segmented whole-tumor volumes of interest and targeted ROIs. ROC curve analysis and the Youden index were used to identify optimal cutoffs for FDG PET and DCE-MRI. Two-by-two contingency tables and percent agreement were used to assess accuracy and concordance. Twenty-six patients (63%) from the cohort underwent next-generation sequencing for tumor genetics. RESULTS: The best-performing FDG PET and DCE-MRI cutoffs achieved sensitivities of 94% and 91%, respectively; specificities of 56% and 89%, respectively; and accuracies of 80% and 83%, respectively. FDG PET and DCE-MRI findings were discordant for 11 patients (27%), with DCE-MRI findings correct for six of these patients (55%). Tumor grade, tumor volume, bevacizumab exposure, and time since radiation predicted discordance between FDG PET and DCE-MRI findings, with an ROC AUC value of 0.78. Isocitrate dehydrogenase gene and receptor tyrosine kinase gene pathway mutations increased the ROC AUC value to 0.83. CONCLUSION: FDG PET and DCE-MRI show comparable accuracy and sensitivity in identifying tumor progression. These modalities were shown to have discordant findings for more than a quarter of the patients assessed. Tumor genetics may contribute to perfusion-metabolism discordance, warranting further investigation.

Can Radiologists Learn From Airport Baggage Screening?: A Survey About Using Fictional Patients for Quality Assurance.

RATIONALE AND OBJECTIVES: For both airport baggage screeners and radiologists, low target prevalence is associated with low detection rate, a phenomenon known as "prevalence effect." In airport baggage screening, the target prevalence is artificially increased with fictional weapons that are digitally superimposed on real baggage. This strategy improves the detection rate of real weapons and also allows airport supervisors to monitor screener performance. A similar strategy using fictional patients could be applied in radiology. The purpose of this study was twofold: (1) to review the psychophysics literature regarding low target prevalence and (2) to survey radiologists' attitudes toward using fictional patients as a quality assurance tool. MATERIALS AND METHODS: We reviewed the psychophysics literature on low target prevalence and airport x-ray baggage screeners. An online survey was e-mailed to all members of the Association of University Radiologists to determine their attitudes toward using fictional patients in radiology. RESULTS: Of the 1503 Association of University Radiologists member recipients, there were 153 respondents (10% response rate). When asked whether the use of fictional patients was a good idea, the responses were as follows: disagree (44%), neutral (25%), and agree (31%). The most frequent concern was the time taken away from doing clinical work (89% of the respondents). CONCLUSIONS: The psychophysics literature supports the use of fictional targets to mitigate the prevalence effect. However, the use of fictional patients is not a popular idea among academic radiologists.

The Effect of Teaching Search Strategies on Perceptual Performance.

RATIONALE AND OBJECTIVES: Radiology expertise is dependent on the use of efficient search strategies. The aim of this study is to investigate the effect of teaching search strategies on trainee's accuracy in detecting lung nodules at computed tomography. MATERIALS AND METHODS: Two search strategies, "scanning" and "drilling," were tested with a randomized crossover design. Nineteen junior radiology residents were randomized into two groups. Both groups first completed a baseline lung nodule detection test allowing a free search strategy, followed by a test after scanning instruction and drilling instruction or vice versa. True positive (TP) and false positive (FP) scores and scroll behavior were registered. A mixed-design analysis of variance was applied to compare the three search conditions. RESULTS: Search strategy instruction had a significant effect on scroll behavior, F(1.3) = 54.2, P < 0.001; TP score, F(2) = 16.1, P < 0.001; and FP score, F(1.3) = 15.3, P < 0.001. Scanning instruction resulted in significantly lower TP scores than drilling instruction (M = 10.7, SD = 5.0 versus M = 16.3, SD = 5.3), t(18) = 4.78, P < 0.001; or free search (M = 15.3, SD = 4.6), t(18) = 4.44, P < 0.001. TP scores for drilling did not significantly differ from free search. FP scores for drilling (M = 7.3, SD = 5.6) were significantly lower than for free search (M = 12.5, SD = 7.8), t(18) = 4.86, P < 0.001. CONCLUSIONS: Teaching a drilling strategy is preferable to teaching a scanning strategy for finding lung nodules.

Pediatric chest CT at chest radiograph doses: when is the ultralow-dose chest CT clinically appropriate?

PURPOSE: Computed tomography (CT) use in emergency departments represents a significant contribution to pediatric patients' exposure to ionizing radiation. Here, we evaluate whether ultralow-dose chest CT can be diagnostically adequate for other diagnoses and whether model-based iterative reconstruction (MBIR) can improve diagnostic adequacy compared to adaptive statistical iterative reconstruction (ASIR) at ultralow doses. METHODS: Twenty children underwent chest CTs: 10 standard-dose reconstructed with ASIR and 10 ultralow-dose reconstructed with ASIR and MBIR. Four radiologists assessed images for their adequacy to exclude five hypothetical diagnoses: foreign body, fracture, lung metastasis, pulmonary infection, and interstitial lung disease. Additionally, pairwise comparison for subjective image quality was used to compare ultralow-dose chest CT with ASIR and MBIR. Radiation dose and objective image noise measures were obtained. RESULTS: For exclusion of an airway foreign body, the adequacy of ultralow-dose CT was comparable to standard-dose (p = 0.6). For the remaining diagnoses, ultralow-dose CT was inferior to standard-dose (p = 0.03-<0.001). MBIR partially recovered the adequacy of ultralow-dose CT to exclude pulmonary infection (p = 0.017), but was suboptimal for the other diagnoses. Image noise was significantly lower with MBIR compared to ASIR in ultralow-dose CT (p < 0.001), although subjective preference showed only a slight advantage of MBIR (58 versus 42%). CONCLUSIONS: Ultralow-dose chest CT may be adequate for airway assessment, but suboptimal for the evaluation parenchymal lung disease. Although MBIR improves objective and subjective image quality, it does not completely restore the diagnostic adequacy of ultralow-dose CT when compared to standard-dose CT.

CT-Guided Percutaneous Lung Biopsies in Patients With Suspicion for Infection May Yield Clinically Useful Information.

OBJECTIVE: The objective of our study was to assess the frequency and time frame with which CT-guided lung biopsies for suspected infection yield information that can affect patient management. MATERIALS AND METHODS: All CT-guided lung biopsies over a 68-month period performed for the purpose of diagnosing a suspected infection were reviewed to determine the proportion that yielded information affecting patient management. Patients were included if infection was the only consideration causing the pulmonary lesion in question. RESULTS: Twenty-one biopsies were performed to identify a specific organism causing infection in patients with suspected infection; all patients were receiving antibiotics, 20 (95%) were immunocompromised, and 15 (71%) had undergone a prior bronchoscopy. Material collected from the biopsy provided a diagnosis in nine (43%) patients, whereas the biopsy results were nondiagnostic in the remaining 12 (57%). Of the nine patients for whom the biopsy yielded a diagnosis, eight biopsies revealed the species causing an infection (38%) and one biopsy (5%) detected posttransplant lymphoproliferative disease. Of the nine diagnoses, management was changed as a result of the biopsy in six patients (29% of all patients). The organisms identified by CT-guided lung biopsy in eight patients were fungi of the order Mucorales (i.e., mucormycosis) (n = 3), Aspergillus (n = 3), Pseudomonas (n = 1), and Nocardia (n = 1). The mean elapsed time between biopsy and pathologic diagnosis was 4 days (median, 3 days). There was no association between prior bronchoscopy and nondiagnostic biopsy results. CONCLUSION: CT-guided lung biopsies in patients with a high pretest suspicion for infection result in information sufficient to change patient management in 29% of patients. Organisms identified in these patients were most frequently fungi.

Instituting a Low-dose CT-guided Lung Biopsy Protocol.

RATIONALE AND OBJECTIVES: We aimed to evaluate whether implementation of a low-dose computed tomography (CT)-guided lung biopsy protocol, with the support of individual radiologists in the section, would lead to immediate and sustained decreases in radiation dose associated with CT-guided lung biopsies. MATERIALS AND METHODS: A low-dose CT-guided lung biopsy protocol was developed with modifications of kilovoltage peak, milliamperes, and scan coverage. Out of 413 CT-guided lung biopsies evaluated over a 3-year period beginning in 2009, 175 performed with a standard protocol before the development of a low-dose protocol, and 238 performed with a low-dose protocol. The dose-length product (DLP) was recorded for each lung biopsy and retrospectively compared between the two protocols. Individual radiologist level DLPs were also compared before and after the protocol change. RESULTS: The mean biopsy dose decreased by 64.4% with the low-dose protocol (113.8 milligray centimeters versus 319.7 milligray centimeters; P < 0.001). This decrease in radiation dose persisted throughout the entire 18 months evaluated following the protocol change. After the protocol change, each attending radiologist demonstrated a decrease in administered radiation dose. The diagnostic outcome rate and complication rate were unchanged over the interval. CONCLUSIONS: Implementation of a low-dose CT-guided lung biopsy protocol resulted in an immediate reduction in patient radiation dose that was seen with all attending radiologists and persisted for at least 18 months. Such an intervention may be considered at other institutions wishing to reduce patient doses.

Detecting Pulmonary Nodules in Lung Cancer Patients Using Whole Body FDG PET/CT, High-resolution Lung Reformat of FDG PET/CT, or Diagnostic Breath Hold Chest CT.

RATIONALE AND OBJECTIVES: Pulmonary nodules can be missed on the non-breath hold computed tomography (CT) portion of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), and for this reason prior studies have advocated for routinely performing dedicated breath hold CT of the chest in addition to PET/CT for routine staging of malignancy. We evaluated the rate of pulmonary nodule detection on standard CT images from whole body PET/CT studies (WB-PET/CT), high-resolution lung reconstruction CT images from PET/CT studies (HR-PET/CT), and diagnostic breath hold chest CT (BH-CT). MATERIALS AND METHODS: A cohort of 25 patients was identified who had a history of lung cancer as well as a PET/CT staging or restaging scan and BH-CT within 30 days of each other. All PET/CTs included a set of CT images using a soft tissue algorithm filter and 3.75- to 5-mm slice thickness, as well as high-resolution reformats with a sharp reconstruction filter and 2-mm slice thickness. The CT images from WB-PET/CT, HR-PET/CT, and BH-CT were reviewed by three radiologists. Significance was analyzed by two-way repeated measures analysis of variance. RESULTS: There were 2.84 nodules found per patient with WB-PET/CT, 3.85 nodules with HR-PET/CT, and 3.91 nodules with BH-CT. When only nodules less than or equal to 8 mm in size were considered, WB-PET/CT also demonstrated significantly fewer nodules (1.98) compared to the HR-PET/CT (2.94) or a BH-CT (2.86) (P < 0.001). No difference in detection rate was noted between the two higher resolution modalities. CONCLUSIONS: More pulmonary nodules are detected on the CT portion of PET/CT studies when high-resolution reformatted images are created and reviewed. The ability to detect nodules with the reformatted images was indistinguishable from dedicated BH-CT. Overall, high-resolution reformats of PET/CT images of the lungs can increase the sensitivity for pulmonary nodule detection, approaching that of dedicated BH-CT. These data suggest that if HR-PET/CT reformats are used, additional dedicated BH-CT is unnecessary for routine staging of lung cancer.

Nonclotted Blood Patch Technique Reduces Pneumothorax and Chest Tube Placement Rates After Percutaneous Lung Biopsies.

PURPOSE: The aim of this study was to determine whether autologous nonclotted blood patch decreases pneumothorax and chest tube placement rates in computed tomography-guided biopsies of the lung. MATERIALS AND METHODS: Percutaneous computed tomography-guided lung biopsies performed over a period of 6 years were retrospectively reviewed to determine the overall rates of pneumothorax and chest tube placement and rates before and after the autologous nonclotted blood patch procedure was instituted as a departmental policy. The effect of the intervention was only assessed in patients in whom a blood patch could be applied, therefore only when the needle traversed an aerated lung and only when the needle remained in the lung at the end of the study. RESULTS: There was a statistically significant decrease in both the rate of pneumothorax [28% (69/245) vs. 42% (80/189); P=0.002] and chest tube placement [4% (10/245) vs. 16% (30/189); P<0.001] in patients who received nonclotted blood patch versus those who did not. Blood patch was performed in 222/312 (71%) eligible patients after the introduction of the blood patch policy. After policy introduction, there was a decreased rate of pneumothorax, with a rate of 32% (101/312) versus 40% (49/122) (P=0.12) and a statistically significant decrease in departmental chest tube placement rates of 6% (20/312) versus 16% (20/122) (P=0.001). CONCLUSIONS: Nonclotted autologous blood patch for percutaneous lung biopsy resulted in significantly decreased pneumothorax and chest tube placement rates in our patient population.

Nondiagnostic Computed Tomography-guided Percutaneous Lung Biopsies Are More Likely When Infection Is Suspected.

PURPOSE: The purpose of this study was to assess the incidence of nondiagnostic computed tomography-guided lung biopsy results, stratified by biopsy indication, and determine the final diagnosis in such cases. MATERIALS AND METHODS: Following institutional review board approval, pathology results from CT-guided lung biopsies over a 5-year period at 2 institutions were categorized as diagnostic or nondiagnostic. Each biopsy's indication was categorized as being for a lesion considered likely to be cancer, infection, or uncertain. For all nondiagnostic biopsies, the medical chart was reviewed to determine the final clinical diagnosis. RESULTS: A total of 660 biopsies were evaluated, 139 (21%) of which were nondiagnostic. Of these 139 patients, the final clinical diagnosis was infection in 37%, cancer in 30%, and a benign noninfectious diagnosis in 10%; 23% remained undiagnosed at last available follow-up. Among the patients in whom there was a high pretest suspicion for cancer, 13% were nondiagnostic, 45% of which were cancer and 27% were infection. Among biopsies of lesions with pretest probability for both cancer and infection, 51% were nondiagnostic; on clinical follow-up these were determined to be infection in 34% and cancer in 14%. When there was high pretest suspicion for infection, 73% were nondiagnostic, of which 13% were cancer on clinical follow-up, and 88% were infection. The rate of nondiagnostic biopsies was statistically significantly different (P<0.001) among the 3 groups. CONCLUSIONS: Nondiagnostic biopsies are common and occur most frequently when there is a moderate or high pretest suspicion for infection. Among all nondiagnostic biopsies, regardless of indication, cancer and infection were diagnosed on follow-up in similar proportions.

Predictors of pathologic outcome of focal FDG uptake in the parotid gland identified on whole-body FDG PET imaging.

PURPOSE: The purpose was to test whether patient's primary malignancy type and presence of F-18-fluorodeoxyglucose (FDG)-avid cervical lymph node(s) are predictors of pathologic outcome of incidental focal FDG-avid parotid lesions. BASIC PROCEDURES: A retrospective cohort study of pathologically proven incidental cases was performed. MAIN FINDINGS: Focal parotid FDG uptake in the setting of head and neck cancer/melanoma [odds ratio (OR)=24.6, P<.01], lymphoma (OR=7.2, P=.02), or FDG-avid cervical lymph node(s) (OR=3.6, P=.07) has a higher odds of representing metastases. No malignant primary parotid tumors were incidentally discovered. PRINCIPAL CONCLUSIONS: In patients with head and neck cancer/melanoma, lymphoma, or FDG-avid cervical lymph node(s), there were higher odds that focal parotid FDG uptake was a metastasis.

Understanding Cost-Effectiveness Analyses: An Explanation Using Three Different Analyses of Lung Cancer Screening.

OBJECTIVE: Cost-effectiveness analyses (CEAs) contribute to informed decision making, at both the practitioner and societal levels; therefore, understanding CEAs is valuable for radiologists. In light of the recently published National Lung Cancer Screening Trial (NLST) CEA, we aim to explain the terminology, methods, and heterogeneity of CEAs. CONCLUSION: We compared the NLST results to two example lung cancer screening CEAs (which do not rely on NLST data). Both examples assessed screening but reached substantially different conclusions.

The incidence of pulmonary embolism and associated FDG-PET findings in IV contrast-enhanced PET/CT.

RATIONALE AND OBJECTIVES: Most fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography with computed tomography (PET/CT) studies are performed on cancer patients. These patients are at increased risk of pulmonary embolism (PE). In this retrospective review, we determined the rate of PE, and the prevalence of associated FDG-PET findings on intravenous (IV) contrast-enhanced PET/CT. MATERIALS AND METHODS: We identified all PET/CT studies performed at our institution with a reported finding of PE between January 2005 and October 2012. The medical record was reviewed for symptoms, which were identified after the diagnosis of PE, and whether the patients received treatment. The prevalence of associated FDG-PET findings was determined. RESULTS: A total of 65 total cases of PE (of 182,72 total PET/CT examinations) were identified of which 59 were previously unknown. This gives an incidental PE (IPE) rate of 0.32%. Of the patients where sufficient clinical information was available, 34 of 36 (94%) were treated either with therapeutic anticoagulation or inferior vena cava filter, and 30 of 36 (83%) were asymptomatic in retrospect. Of the patients with IPE, we found nine (15.2%) with associated focal pulmonary artery hypermetabolism, three (5.1%) with hypermetabolic pulmonary infarction, and one with increased isolated right ventricular FDG uptake (1.7%). One case of chronic PE demonstrated a focal hypometabolic filling defect in a pulmonary artery on PET. CONCLUSIONS: We found IPE in 0.32% of PET/CT scans. Focal pulmonary artery hypermetabolism or hypometabolism, and hypermetabolic pulmonary artery infarction with the "rim sign" were uncommonly associated with PE. These findings could raise the possibility of IPE in non-IV contrast-enhanced PET/CT studies.

Cardiovascular MR imaging after surgical correction of tetralogy of Fallot: approach based on understanding of surgical procedures.

Tetralogy of Fallot (TOF) is one of the most common congenital heart diseases for which patients are referred for postoperative magnetic resonance (MR) imaging evaluation. The most common surgical procedures for TOF repair include infundibulectomy, transannular pulmonary artery patch repair, and right ventricle-pulmonary artery conduit placement. In the past few decades, surgery has proved successful, but most patients require repeat imaging throughout their lives. MR imaging is now frequently used for morphologic and functional evaluation after TOF repair. The most common late postoperative sequelae and residual lesions include right ventricular outflow tract aneurysm and dyskinesis, conduit failure, pulmonary regurgitation, tricuspid regurgitation, right ventricular failure, residual main and branch pulmonary artery stenosis, branch pulmonary artery aneurysm, left pulmonary artery kinking, and residual or recurrent ventricular septal defect. The imaging approach for the evaluation of patients with repaired TOF should be guided by the surgical procedure used and the complications that are expected. Knowledge of the most common postoperative problems and their cardiovascular MR imaging appearances is essential for good radiology practice in this clinical setting.