Johnson, Tucker F.

Dividing the interpretation of concurrently acquired chest and abdominal CT images between two radiologists has advantages, and the potential problems can be mitigated by awareness, defined expectations, and communication.

Background: Tissue factor pathway inhibitor (TFPI) is a key regulator of the tissue factor/factor VIIa complex. Systemic genetic disruption of TFPI exon 4 results in intrauterine lethality in mice. As such, the ability to study the biologic and tissue specific effects of TFPI deficiency has been limited. To define the tissue specific roles of TFPI we utilized a Cre-lox strategy and generated mice with flanking loxP sites surrounding exon 4 (encodes for the K1 domain). Homozygous floxed mice (TFPI Flox ) were crossed with the Tie2 Cre + or LysM Cre + mice and subsequently inbred to create homozygously floxed mice expressing Cre (TFPI Tie2 or TFPI LysM ). Methods and Results: The presence and efficiency of the deleted mRNA product was determined by RT-PCR. TFPI Tie2 and TFPI LysM mice were phenotypically similar to TFPI Flox littermates including weight, blood counts, and prothrombin and activated partial thromboplastin times. TFPI Tie2 mice have complete deletion in endothelial cells, blood cells and bone marrow cells. TFPI LysM mice show partial deletion in blood cells and complete deletion in macrophages. TFPI Tie2 mice had a 60% reduction (P < 0.0001) in circulating TFPI activity compared to TFPI Flox littermate controls. TFPI LysM mice did not have a significant reduction in circulating TFPI activity levels compared to their TFPI Flox counterparts. Neither TFPI Tie2 nor TFPI LysM mice had significant changes in hemostasis compared to TFPI Flox mice as determined by a tail bleeding assay. In an ADP-induced model of thromboembolism there were no significant changes in mortality between the TFPI Tie2 or TFPI LysM and their TFPI Flox littermates. In a ferric chloride model of arterial thrombosis, TFPI Tie2 mice had a significant reduction (P < 0.05) in time to occlusion while TFPI LysM mice did not differ compared to TFPI Flox mice. Conclusions: Deletion of TFPI from cells expressing Tie2 or LysM is consistent with normal development and hemostasis. TFPI Tie2 mice have decreased circulating levels of TFPI and an enhanced thrombotic response to ferric chloride. These data support an important regulatory role for EC TFPI in arterial thrombosis.

Context.— Respiratory infections complicate lung transplantation and increase the risk of allograft dysfunction. Allograft lungs may have different susceptibilities to infection than native lungs, potentially leading to different disease severity in lungs of single lung transplant recipients (SLTRs). Objective.— To study whether infections affect allograft and native lungs differently in SLTRs but similarly in double LTRs (DLTRs). Design.— Using an institutional database of LTRs, medical records were searched, chest computed tomography studies were systematically reviewed, and histopathologic features were recorded per lung lobe and graded semiquantitatively. A multilobar-histopathology score (MLHS) including histopathologic data from each lung and a bilateral ratio (MLHSratio) comparing histopathologies between both lungs were calculated in SLTRs and compared to DLTRs. Results.— Six SLTRs died of infection involving the lungs. All allografts showed multifocal histopathologic evidence of infection, but at least 1 lobe of the native lung was uninvolved. In 4 of 5 DLTRs, histopathologic evidence of infection was seen in all lung lobes. On computed tomography, multifocal ground-glass and/or nodular opacities were found in a bilateral distribution in all DLTRs but in only 2 of 6 SLTRs. In SLTRs, the MLHSAllograft was higher than MLHSNative (P = .02). The MLHSratio values of SLTR and DLTR were significantly different (P &lt; .001). Conclusions.— Allograft and native lungs appear to harbor different susceptibilities to infections. The results are important for the management of LTRs.

Objective The aim of this study was to evaluate the clinical impact of a higher spatial resolution, full field-of-view investigational photon-counting detector computed tomography (PCD-CT) on radiologist confidence in imaging findings and diagnosis of usual interstitial pneumonia (UIP) compared with conventional energy-integrating detector CT (EID-CT). Materials and Methods Patients suspected of interstitial lung disease were scanned on a PCD-CT system after informed consent and a clinically indicated EID-CT. In 2 sessions, 3 thoracic radiologists blinded to clinical history and scanner type evaluated CT images of the right and left lungs separately on EID- or PCD-CT, reviewing each lung once/session, rating confidence in imaging findings of reticulation, traction bronchiectasis, honeycombing, ground-glass opacities (GGOs), mosaic pattern, and lower lobe predominance (100-point scale: 0–33, likely absent; 34–66, indeterminate; 67–100, likely present). Radiologists also rated confidence for the probability of UIP (0–20, normal; 21–40, inconsistent with UIP; 41–60, indeterminate UIP; 61–81; probable UIP; 81–100, definite UIP) and graded image quality. Because a confidence scale of 50 represented completely equivocal findings, magnitude score (the absolute value of confidence scores from 50) was used for analysis (higher scores were more confident). Image noise was measured for each modality. The magnitude score was compared using linear mixed effects regression. The consistency of findings and diagnosis between 2 scanners were evaluated using McNemar test and weighted κ statistics, respectively. Results A total of 30 patients (mean age, 68.8 ± 11.0 years; M:F = 18:12) underwent conventional EID-CT (median CTDIvol, 7.88 mGy) and research PCD-CT (median CTDIvol, 6.49 mGy). The magnitude scores in PCD-CT were significantly higher than EID-CT for imaging findings of reticulation (40.7 vs 38.3; P = 0.023), GGO (34.4 vs 31.7; P = 0.019), and mosaic pattern (38.6 vs 35.9; P = 0.013), but not for other imaging findings (P ≥ 0.130) or confidence in UIP (34.1 vs 22.2; P < 0.059). Magnitude score of probability of UIP in PCD-CT was significantly higher than EID-CT in one reader (26.0 vs 21.5; P = 0.009). Photon-counting detector CT demonstrated a decreased number of indeterminate GGO (17 vs 26), an increased number of unlikely GGO (74 vs 50), and an increased number of likely reticulations (140 vs 130) relative to EID-CT. Interobserver agreements among 3 readers for imaging findings and probability of UIP were similar between PCD-CT and EID-CT (intraclass coefficient: 0.507–0.818 vs 0.601–0.848). Photon-counting detector CT had higher scores in overall image quality (4.84 ± 0.38) than those in EID-CT (4.02 ± 0.40; P < 0.001) despite increased image noise (mean 85.5 vs 36.1 HU). Conclusions Photon-counting detector CT provided better image quality and improved the reader confidence for presence or absence of imaging findings of reticulation, GGO, and mosaic pattern with idiosyncratic improvement in confidence in UIP presence.

9135 Background: Bronchial carcinoid (BC) is often categorized into multifocal (MBC) or solitary (SBC). MBC, excluding tumorlet and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia, is considered a relatively uncommon subgroup of BC, with much of the MBC literature stemming from case reports/small series. Our study analyzes MBC among a large cohort of 569 patients with BC and argues for change to the current clinical understanding of MBC. We suggest using the term bronchial neuroendocrine tumor (bNET) to more accurately represent its cells of origin and move away from “carcinoid” (historically meaning “carcinoma-like”) and the outdated associated connotation that carcinoids all have a similar, benign clinical and biological behavior. Methods: Using the Mayo Clinic Epidemiology and Genetics of Lung Cancer Database with Institutional Review Board approval, we retrospectively reviewed 569 patients with bNET (204 males, 365 females) presenting to Mayo Clinic Rochester between 1/1997-12/2012. We used univariate and multivariate Cox regression analyses to evaluate factors affecting overall survival. Results: 80 patients (of 569, 14.1%) were diagnosed with multifocal (MbNET) and 489 with solitary (SbNET). Two-sided Fisher’s exact tests found that older age, female gender, never having smoked cigarettes, and tumorlets were associated with MbNET diagnosis. Family lung cancer history, histopathologic grading (pathology: typical vs. atypical), Ki67, and presence of syndromes (carcinoid, Cushing, and MEN1 syndromes) were similar between MbNET and SbNET groups. Most MbNET cases were stage III-IV at the time of diagnosis, while the majority of SbNET cases were stage I. 5-year OS (83%) and 5-year PFS (75%) of MbNET patients were higher than those of their SbNET counterparts (74% and 68%, respectively). Metastasis status was an independent prognostic factor of poor OS in SbNET (P<0.001) but not in MbNET (P=0.71)(Table). Conclusions: Clinical, radiologic, and histopathologic characteristics and prognostic factors differed between SbNET and MbNET. MbNET arose as a new entity often with advanced stage disease, but good prognosis, which does not follow the NSCLC TNM staging system as in the 2009 NCCN guidelines (used during this study) or the updated 2021 NCCN guidelines which continue to stage lung carcinoid similarly to NSCLC. It may be beneficial to consider multifocal lung carcinoid instead as multifocal bNET, a new clinical entity, warranting a novel staging approach that more accurately reflects prognosis.[Table: see text]

Context.— Studies of lungs in patients with COVID-19 have focused on early findings. Objective.— To systematically study histopathologic and imaging features and presence of SARS-CoV-2 RNA in lung tissue from patients in later stages of COVID-19. Design.— Autopsies, explants, surgical lung biopsies, transbronchial biopsies, cryobiopsies, and needle biopsies from patients with COVID-19 whose onset of symptoms/confirmed diagnosis was more than 28 days before the procedure were studied. Available images were reviewed. Reverse transcription droplet digital polymerase chain reaction for SARS-CoV-2 RNA was performed on lung tissue. Results.— Of 44 specimens (43 patients; median age, 59.3 years; 26 [60.5%] male) features of acute lung injury (ALI) were seen in 39 (88.6%), predominantly organizing pneumonia and diffuse alveolar damage, up to 298 days after onset of COVID-19. Fibrotic changes were found in 33 specimens (75%), most commonly fibrotic diffuse alveolar damage (n = 22) and cicatricial organizing pneumonia (n = 12). Time between acquiring COVID-19 and specimen was shorter in patients with diffuse ALI (median, 61.5 days) compared with patients with focal (140 days) or no ALI (130 days) (P = .009). Sixteen (of 20; 80%) SARS-CoV-2 reverse transcription droplet digital polymerase chain reaction tests were positive, up to 174 days after COVID-19 onset. Time between COVID-19 onset and most recent computed tomography in patients with consolidation on imaging was shorter (median, 43.0 days) versus in patients without consolidation (87.5 days; P = .02). Reticulations were associated with longer time to computed tomography after COVID-19 onset (median, 82 versus 23.5 days; P = .006). Conclusions.— ALI and SARS-CoV-2 RNA can be detected in patients with COVID-19 for many months. ALI may evolve into fibrotic interstitial lung disease.

Background: Amyloidosis can involve any compartment in the thorax. We aimed to explore the clinical and radiologic presentation, treatment, and clinical course of airway amyloidosis. Methods: A computer-assisted search was performed to identify patients who had biopsy-proven airway amyloidosis and were evaluated at Mayo Clinic in Rochester, MN, from January 1, 1997 through December 31, 2019. Demographic, clinical, and radiologic features along with clinical outcomes were analyzed. Results: We identified 43 patients who had airway amyloidosis. Median age was 60 years (range: 33 to 91 y), and 58% were female. Shortness of breath (63% of patients) and cough (44%) were the most common presenting symptoms. Most patients (82%) had localized amyloidosis with light chain being the most common amyloid type; 63% had tracheobronchial amyloidosis, and 23% had tracheal and upper airway involvement. On computed tomography of the chest, the most common findings were airway wall thickening with nodularity (60% of patients), airway calcification (53%), and airway occlusion without collapse (47%). On bronchoscopy (33 patients), the extent of amyloid involvement was most commonly submucosal (n=15) or nodular (n=8). External beam radiotherapy was the most common treatment modality. Among the 30 patients who had follow-up at our institution, the prognosis appeared to depend on the extent of the disease and whether patients had localized or systemic amyloidosis. Conclusion: Computed tomography of the chest, bronchoscopy, and biopsy are needed to establish the diagnosis of airway amyloidosis, and systemic amyloidosis should be ruled out. Treatment of amyloidosis requires a multidisciplinary approach.

Objectives: The objectives of the study were to estimate the impact of high matrix image reconstruction on chest computed tomography (CT) compared to standard image reconstruction. Material and Methods: This retrospective study included patients with interstitial or parenchymal lung disease, airway disease, and pulmonary nodules who underwent chest CT. Chest CT images were reconstructed using high matrix (1024 × 1024) or standard matrix (512 × 512), with all other parameters matched. Two radiologists, blinded to reconstruction technique, independently examined each lung, viewing image sets side by side and rating the conspicuity of imaging findings using a 5-point relative conspicuity scale. The presence of pulmonary nodules and confidence in classification of internal attenuation was also graded. Overall image quality and subjective noise/artifacts were assessed. Results: Thirty-four patients with 68 lungs were evaluated. Relative conspicuity scores were significantly higher using high matrix image reconstruction for all imaging findings indicative of idiopathic lung fibrosis (peripheral airway visualization, interlobular septal thickening, intralobular reticular opacity, and end-stage fibrotic change; P ≤ 0.001) along with emphysema, mosaic attenuation, and fourth order bronchi for both readers (P ≤ 0.001). High matrix reconstruction did not improve confidence in the presence or classification of internal nodule attenuation for either reader. Overall image quality was increased but not subjective noise/artifacts with high matrix image reconstruction for both readers (P < 0.001). Conclusion: High matrix image reconstruction significantly improves the conspicuity of imaging findings reflecting interstitial lung disease and may be useful for diagnosis or treatment response assessment.