Faculty Bibliography

OBJECTIVES/OBJECTIVE:F-FDG uptake is associated with hypertension, and if it correlates to elevated pulmonary pressures. BACKGROUND: METHODS:F-FDG uptake in the PA was quantified according to maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR) and compared with available results from right heart catheterization (RHC) or transthoracic echocardiography (TTE). RESULTS:F-FDG uptake in the PA wall showed a sensitivity of 33% and specificity of 96% for separating patients with PH based on RHC-derived PA pressures. SUVmax and TBR in the PA wall correlated with PA pressure derived from RHC and/or TTE. CONCLUSIONS:F-FDG uptake by PET/CMR in the PA is associated with PH and that its intensity correlates with PA pressure.

Spread through air spaces (STAS) is reportedly associated with worse prognosis in sublobar resections of lung adenocarcinoma. Recently, it was proposed that STAS detected on frozen sections can be an indication for lobectomy instead of sublobar resection. We undertook this study to evaluate the reliability of STAS assessment on frozen sections compared to permanent sections, as well as the associations among STAS, tumor grade, and recurrence-free survival (RFS) after sublobar resection. A total of 163 stage I lung adenocarcinoma resections with frozen sections were identified retrospectively. For each case, and for frozen and permanent sections separately, the presence or absence of STAS, as well as the tumor grade, were recorded. Compared to permanent sections, STAS detection on frozen sections had low sensitivity (55%), low positive predictive value (48%), and fair agreement (K = 0.34), whereas there was higher specificity (80%) and negative predictive value (85%). Accuracy was 74%. Tumor grade assessment on frozen sections showed higher sensitivity (77%), positive predictive value (90%), agreement (K = 0.72), specificity (94%), and accuracy (87%), and the same negative predictive value (85%). High-grade histology on frozen sections was associated with shorter RFS (p = 0.02), whereas STAS on frozen sections was not (p = 0.47). Our results suggest that the intraoperative detection of STAS has low sensitivity and positive predictive value. False-positive results may lead to overtreatment of patients with lung cancer. The determination of tumor grade on frozen sections offers better sensitivity and specificity, plus it is associated with RFS, whereas STAS on frozen sections is not. Further study is needed to explore the utility of assessing tumor grade on frozen sections.

BACKGROUND:Histological analyses of deep vein thrombi (DVT) are based on autopsy samples and animal models. No prior study has reported on thrombus composition following percutaneous mechanical extraction. As elements of chronicity and organization render thrombus resistant to anticoagulation and thrombolysis, a better understanding of clot evolution may inform therapies. METHODS:We performed histologic evaluation of DVTs from consecutive patients undergoing mechanical thrombectomy for extensive iliofemoral DVTs using the Clottriever/ Flowtriever device (Inari Medical, Irvine, CA). Thrombi were scored in a semi-quantitative manner based on the degree of fibrosis (collagen deposition on trichrome stain), and organization (endothelial growth with capillaries and fibroblastic penetration). RESULTS:Twenty-three specimens were available for analysis with 20 presenting with acute DVT (≤14 days from symptom onset). Eleven of 23 patients (48%) had >5% fibrosis (collagen deposition) and 14/23 patients (61%) had >5% organization (endothelial growth, capillaries, fibroblasts). Four patients with acute DVT had ≥25% organized thrombus and 2 had ≥ 25% collagen deposition. Among the 20 patients with acute DVT, 40% had >5% fibrosis and 55% had > 5% organization. Acuity of DVT did not correlate with the fibrosis or organizing scores. CONCLUSIONS:A large proportion of patients with acute DVT have histologic elements of chronicity and fibrosis. A better understanding of the relationship between such elements and response to anticoagulants and fibrinolytics may inform our approach to therapeutics.

BACKGROUND:With the high prevalence of COVID-19 infections worldwide, the multisystem inflammatory syndrome in adults (MIS-A) is becoming an increasingly recognized entity. This syndrome presents in patients several weeks after infection with COVID-19 and is associated with thrombosis, elevated inflammatory markers, hemodynamic compromise and cardiac dysfunction. Treatment is often with steroids and intravenous immunoglobulin (IVIg). The pathologic basis of myocardial injury in MIS-A, however, is not well characterized. In our case report, we obtained endomyocardial biopsy that revealed a pattern of myocardial injury similar to that found in COVID-19 cardiac specimens. CASE PRESENTATION:A 26-year-old male presented with fevers, chills, headache, nausea, vomiting, and diarrhea 5 weeks after his COVID-19 infection. His SARS-CoV-2 PCR was negative and IgG was positive, consistent with prior infection. He was found to be in cardiogenic shock with biventricular failure, requiring inotropes and diuretics. Given concern for acute fulminant myocarditis, an endomyocardial biopsy (EMB) was performed, showing an inflammatory infiltrate consisting predominantly of interstitial macrophages with scant T lymphocytes. The histologic pattern was similar to that of cardiac specimens from COVID-19 patients, helping rule out myocarditis as the prevailing diagnosis. His case was complicated by persistent hypoxemia, and a computed tomography scan revealed pulmonary emboli. He received IVIg, steroids, and anticoagulation with rapid recovery of biventricular function. CONCLUSIONS:MIS-A should be considered as the diagnosis in patients presenting several weeks after COVID-19 infection with severe inflammation and multi-organ involvement. In our case, EMB facilitated identification of MIS-A and guided therapy. The patient's biventricular function recovered with IVIg and steroids.

PURPOSE/UNASSIGNED:Acute thromboembolic disease of the innominate artery (IA) poses a unique set of therapeutic challenges, owing to its contribution to both the cerebral and upper extremity circulation, and risks of distal embolization via the carotid and subclavian arteries, respectively. Herein, we present a 74-year-old female who presents with acute IA thrombus treated successfully with right axillary and common carotid exposure and aspiration catheter-directed mechanical thrombectomy (CDT). Furthermore, an emerging use of CDT and its application in acute thromboembolism are outlined. CASE REPORT/UNASSIGNED:A 74-year-old female with history of right lung transplant for pulmonary fibrosis with severe pulmonary hypertension, and stage IIIA left lung adenocarcinoma status post left lower lobectomy undergoing adjuvant chemotherapy presented with acute IA thrombus and right-sided stroke. She was treated successfully with right axillary and common carotid exposure and aspiration CDT. Computed tomography angiography performed 1 month postoperatively confirmed patent IA with no evidence of residual or recurrent thrombus. CONCLUSION/UNASSIGNED:There are currently no standard guidelines on the management of acute IA thromboembolism, with mostly individual cases reported in the literature describing this rare entity. Nevertheless, this unique clinical entity mandates expeditious diagnostic and therapeutic approaches in order to avoid permanent neurologic deficits from distal embolization. Our case demonstrates that aspiration CDT may be an effective treatment modality for patients with acute IA thrombus.

Lung transplant is increasingly performed for the treatment of end-stage lung disease. As the number of lung transplants and transplant centers continues to rise, radiologists will more frequently participate in the care of patients undergoing lung transplant, both before and after transplant. Potential donors and recipients undergo chest radiography and CT as part of their pretransplant assessment to evaluate for contraindications to transplant and to aid in surgical planning. After transplant, recipients undergo imaging during the postoperative hospitalization and also in the long-term outpatient setting. Radiologists encounter a wide variety of conditions leading to end-stage lung disease and a myriad of posttransplant complications, some of which are unique to lung transplantation. Familiarity with these pathologic conditions, including their imaging findings and their temporal relationship to the transplant, is crucial to accurate radiologic interpretation. Knowledge of the surgical techniques and expected postoperative appearance prevents confusing normal posttransplant imaging findings with complications. A basic understanding of the indications, contraindications, and surgical considerations of lung transplant aids in imaging interpretation and protocoling and also facilitates communication between radiologists and transplant physicians. Despite medical and surgical advances over the past several decades, lung transplant recipients currently have an average posttransplant life expectancy of only 6.7 years. As members of the transplant team, radiologists can help maximize patient survival and hopefully increase posttransplant life expectancy and quality of life in the coming decades. ^©RSNA, 2021 An invited commentary by Bierhals is available online. Online supplemental material is available for this article.

Cullin 4A and 4B ubiquitin ligases are often highly accumulated in human malignancies, and are believed to possess oncogenic properties. However, the underlying mechanisms by which CUL4A and CUL4B promote pulmonary tumorigenesis remain largely elusive. In this study, we report that both CUL4A and CUL4B are highly expressed in non-small cell lung cancer (NSCLC) patients, and high expression of both is associated with disease progression, chemotherapy resistance, and poor survival in adenocarcinomas. Depletion of CUL4A (CUL4A^k/d) or CUL4B (CUL4B^k/d) leads to cell cycle arrest at G1 and loss of proliferation and viability of NSCLC cells both in culture and in a lung cancer xenograft model, suggesting that CUL4A and 4B are oncoproteins required for tumor maintenance of certain NSCLC. Mechanistically, increased accumulation of the cell cycle-dependent kinase inhibitor p21/Cip1/WAF1 was observed in lung cancer cells upon CUL4 silencing. Knockdown of p21 rescued the G1 arrest of CUL4A^k/d or CUL4B^k/d NSCLC cells and allowed proliferation to resume. These findings reveal that p21 is the primary downstream effector of lung adenocarcinoma dependence on CUL4, highlight the notion that not all substrates respond equally to abrogation of the CUL4 ubiquitin ligase in NSCLCs, and imply that CUL4A^high CUL4B^high may serve as a prognostic marker and therapeutic target for NSCLC patients.