Publications

Fibrolamellar hepatocellular carcinoma (FL-HCC) is a rare primary liver tumor that typically presents at an advanced stage in early adolescents and adults with no underlying liver disease. Surgical resection is the first-line treatment, and patients who are not surgical candidates face limited treatment options with poor long-term outcomes. Herein we report the first documented, technically successful treatment of FL-HCC with extrahepatic spread using transarterial radioembolization (TARE) in a 16-year-old male patient with surgically unresectable disease. Subsequent imaging revealed tumor necrosis and a 20% reduction in size, and the patient survived 20 months post-treatment, a marked improvement relative to historical data in the literature. Further research should examine the potential role of yttrium-90 TARE in the treatment of FL-HCC patients with metastatic disease.

BACKGROUND: To evaluate the added value of the hepatobiliary (HPB) phase in gadoxetic acid-enhanced magnetic resonance imaging (MRI) in characterizing newly discovered indeterminate focal liver lesions in non-cirrhotic patients.

RESULTS: One-hundred and twenty-five non-cirrhotic patients (median age, 46 years; range, 20-85 years; 100 females) underwent gadoxetic acid-enhanced MRI, including the 20-min delayed HPB phase, for characterization of newly discovered focal liver lesions. Images were independently evaluated by two blinded, board-certified abdominal radiologists (R1 and R2) who characterized liver lesions without and with assessment of the HPB phase images in two separate readout sessions. Confidence in diagnosis was scored on a scale from 0 to 3. Inter-observer agreement was assessed using Cohen κ statistics. Change in diagnosis and confidence in diagnosis were evaluated by Wilcoxon signed rank test. There was no significant change in diagnosis before and after evaluation of the HPB phase for both readers (p = 1.0 for R1; p = 0.34 for R2). Confidence in diagnosis decreased from average 2.8 ± 0.45 to 2.6 ± 0.59 for R1 and increased from 2.6 ± 0.83 to 2.8 ± 0.46 for R2. Change in confidence was only statistically significant for R1 (p = 0.003) but not significant for R2 (p = 0.49). Inter-reader agreement in diagnosis was good without (k = 0.66) and with (k = 0.75) inclusion of the HPB phase images.

CONCLUSIONS: The added information obtained from the HPB phase of gadoxetic acid-enhanced MRI does not change the diagnosis or increase confidence in diagnosis when evaluating new indeterminate focal liver lesions in non-cirrhotic patients.

BACKGROUND: The choroid plexus is a major contributor to the generation of cerebrospinal fluid (CSF) and the maintenance of its electrolyte and metabolite balance. Here, we sought to characterize the blood flow dynamics of the choroid plexus using arterial spin labeling (ASL) MRI to establish ASL as a non-invasive tool for choroid plexus function and disease studies.

METHODS: Seven healthy volunteers were imaged on a 3T MR scanner. ASL images were acquired with 12 labeling durations and post labeling delays. Regions of the choroid plexus were manually segmented on high-resolution T1 weighted images. Choroid plexus perfusion was characterized with a dynamic ASL perfusion model. Cerebral gray matter perfusion was also quantified for comparison.

RESULTS: Kinetics of the ASL signal were clearly different in the choroid plexus than in gray matter. The choroid plexus has a significantly longer T1 than the gray matter (2.33 ± 0.30 s vs. 1.85 ± 0.10 s, p < 0.02). The arterial transit time was 1.24 ± 0.20 s at the choroid plexus. The apparent blood flow to the choroid plexus was measured to be 39.5 ± 10.1 ml/100 g/min and 0.80 ± 0.31 ml/min integrated over the posterior lateral ventricles in both hemispheres. Correction with the choroid plexus weight yielded a blood flow of 80 ml/100 g/min.

CONCLUSIONS: Our findings suggest that ASL can provide a clinically feasible option to quantify the dynamic characteristics of choroid plexus blood flow. It also provides useful reference values of the choroid plexus perfusion. The long T1 of the choroid plexus may suggest the transport of water from arterial blood to the CSF, potentially providing a method to quantify CSF generation.

RATIONALE AND OBJECTIVES: Medical schools were upended by the COVID-19 pandemic, resulting in suspension of all in-person educational activities, and leaving clinical clerkships on hold indefinitely. A virtual curriculum and novel teaching methods were needed to fulfill curricular requirements. We developed a comprehensive virtual radiology clerkship and evaluated the efficacy of this novel method of teaching.

MATERIALS AND METHODS: A 4-week virtual radiology clerkship was designed to accommodate medical students who had not yet completed the required clerkship. The design included online flipped classroom modules, large group didactic lectures, and small group homeroom activities. Student performance was assessed via a standardized online final exam. Feedback from students was collected using online surveys. Student performance was compared to the in-person radiology clerkship.

RESULTS: One hundred and eleven medical students were enrolled in the virtual radiology clerkship. Final exam scores were similar to the in-person clerkship. Students indicated that small group homeroom activities had the highest overall satisfaction. Students recognized enthusiastic teachers regardless of class format. Exceptional course content and organization were also noted. Course weaknesses included didactic lecture content which was repetitive or too advanced, the limited opportunity to build personal connections with faculty, and scheduling conflicts with other competing school activities.

CONCLUSION: A completely virtual radiology core clerkship can be a successful educational experience for medical students during a time when remote learning is required. A small group learning environment is most successful for student engagement. Personal connections between faculty and students can be challenging in a virtual course.

RATIONALE AND OBJECTIVES: To analyze the performances of diameter-based measurements, either using diameters, or by calculating diameter-based volumes, as compared to volume measurements in assessing growth of pulmonary adenocarcinomas manifesting as subsolid nodules on CT.

MATERIALS AND METHODS: In this IRB-approved, retrospective study, 74 pulmonary adenocarcinomas presenting as subsolid nodules and resected in 69 patients (21 men, 48 women, mean age 70 ± 9 years) were included. Three CTs were available for each patient. Nodule size on each CT was assessed with diameter measurements, calculated volume based on diameter measurements, and measured volume. Nodule growth was defined as an increase of measured volume ≥25% between two sequential CTs. Sensitivity, specificity, accuracy, positive and negative predictive values of diameter-based measurements for growth assessment were calculated. Nodule characteristics were compared with nonparametric tests and analysis of variance.

RESULTS: There were fewer growing nodules during CT1-CT2 interval (n = 22, 30%) than during CT2-CT3 interval (n = 33, 45%, p =.060). Specificity and negative predictive value of diameter-based measurements for growth assessment ranged respectively from 52 to 77% and 81 to 83% between CT1 and CT2, and from 66 to 76% and 79 to 90% between CT2 and CT3. Nongrowing nodules tended to be larger, regardless how size was measured, and some of these differences in size were statistically significant (p =.002 to .046).

CONCLUSION: For pulmonary adenocarcinomas presenting as subsolid nodules on CT, diameter-based assessment of nodule volume is reasonably accurate at confirming a lack of nodule growth but may overestimate actual growth, as compared to growth assessment based on measured volume.

OBJECTIVE: To evaluate gender and racial profiles of US academic radiology faculty.

MATERIALS AND METHODS: This is a retrospective analysis of the American Association of Medical College database of radiology faculty members from 2006 to 2017 by academic rank, chair position, race or ethnicity, and gender. The data were described with annual proportions and average annual counts and fit to a Poisson regression model. Comparison data were taken from American Association of Medical College on matriculants at US medical schools and from ACGME on radiology residents.

RESULTS: Women increased significantly in the ranks of professor by 4.5%, associate professor by 4.8%, and assistant professor by 4.8% (P < .05). Asian and multiple race non-Hispanic radiologists increased in the rank of professor by 5.9% and 3.1%, respectively (P < .05). Among department chairs, only women and Asian faculty increased by 6.4% and 7.5%, respectively (P < .05). The proportion of women chairs increased from 10.0% (19 of 191) in 2006 to 17.4% (39 of 224) in 2017. Black and Hispanic chairs collectively represented less than 10% of the total chairs every year.

DISCUSSION: The significant percent annual increase in women faculty in academic ranks and chair positions suggests that the radiology faculty is becoming more diverse. However, the decreasing proportion of women with increasing academic ranks within each year of the study period suggests attrition or lack of promotion of women radiology faculty. The disparity in black and Hispanic faculty members and chairs suggests that emphasis should continue to be placed on tailored recruitment.

OBJECTIVE: To examine technical-, patient-, tumor-, and treatment-related factors associated with NIR guided SLN identification.

BACKGROUND: Missed nodal disease correlates with recurrence in early stage NSCLC. NIR-guided SLN mapping may improve staging and outcomes through identification of occult nodal disease.

METHODS: Retrospective analysis of 2 phase I clinical trials investigating NIR-guided SLN mapping utilizing ICG in patients with surgically resectable NSCLC.

RESULTS: In total, 66 patients underwent NIR-guided SLN mapping and lymphadenectomy after peritumoral ICG injection. There was significantly increased likelihood of SLN identification with injection dose ≥1 mg compared to <1 mg (65.2% vs 35.0%, P = 0.05), lung ventilation after injection (65.2% vs 35.0%, P = 0.05), and albumin dissolvent (68.1%) compared to fresh frozen plasma (28.6%) and sterile water (20.0%) (P = 0.01). In patients receiving the optimized ICG injection, there was significantly increased likelihood of SLN identification with radiologically solid nodules compared to sub-solid nodules (77.4% vs 33.3%, P = 0.04) and anatomic resection compared to wedge resection (88.2% vs 52.2%, P = 0.04). Disease-free and overall survival are 100% in those with a histologically negative SLN identified (n = 25) compared to 73.6% (P = 0.02) and 63.6% (P = 0.01) in patients with node negative NSCLC established via routine lymphadenectomy alone (n = 22).

CONCLUSIONS: SLN(s) are more reliably identified with ICG dose ≥1 mg, albumin dissolvent, post-injection lung ventilation, radiologically solid nodules, and anatomic resections. To date, N0 status when established via NIR SLN mapping seems to be associated with decreased recurrence and improved survival after surgery for NSCLC.

The COVID-19 pandemic has led to extensive morbidity and mortality throughout the world. Clinical features that drive SARS-CoV-2 pathogenesis in humans include inflammation and thrombosis, but the mechanistic details underlying these processes remain to be determined. In this study, we demonstrate endothelial disruption and vascular thrombosis in histopathologic sections of lungs from both humans and rhesus macaques infected with SARS-CoV-2. To define key molecular pathways associated with SARS-CoV-2 pathogenesis in macaques, we performed transcriptomic analyses of bronchoalveolar lavage and peripheral blood and proteomic analyses of serum. We observed macrophage infiltrates in lung and upregulation of macrophage, complement, platelet activation, thrombosis, and proinflammatory markers, including C-reactive protein, MX1, IL-6, IL-1, IL-8, TNFα, and NF-κB. These results suggest a model in which critical interactions between inflammatory and thrombosis pathways lead to SARS-CoV-2-induced vascular disease. Our findings suggest potential therapeutic targets for COVID-19.

Background Confirming that subsolid adenocarcinomas show exponential growth is important because it would justify using volume doubling time to assess their growth. Purpose To test whether the growth of lung adenocarcinomas manifesting as subsolid nodules at chest CT is accurately represented by an exponential model. Materials and Methods Patients with lung adenocarcinomas manifesting as subsolid nodules surgically resected between January 2005 and May 2018, with three or more longitudinal CT examinations before resection, were retrospectively included. Overall volume (for all nodules) and solid component volume (for part-solid nodules) were measured over time. A linear mixed-effects model was used to identify the growth pattern (linear, exponential, quadratic, or power law) that best represented growth. The interactions between nodule growth and clinical, CT morphologic, and pathologic parameters were studied. Results Sixty-nine patients (mean age, 70 years ± 9 [standard deviation]; 48 women) with 74 lung adenocarcinomas were evaluated. Overall growth and solid component growth were better represented by an exponential model (adjusted R2 = 0.89 and 0.95, respectively) than by a quadratic model (r2 = 0.88 and 0.93, respectively), a linear model (r2 = 0.87 and 0.92, respectively), or a power law model (r2 = 0.82 and 0.93, respectively). Faster overall volume growth was associated with a history of lung cancer (P < .001), a baseline nodule volume less than 500 mm3 (P = .03), and histologic findings of invasive adenocarcinoma (P < .001). The median volume doubling time of noninvasive adenocarcinoma was significantly longer than that of invasive adenocarcinoma (939 days [interquartile range, 588-1563 days] vs 678 days [interquartile range, 392-916 days], respectively; P = .01). Conclusion The overall volume growth of adenocarcinomas manifesting as subsolid nodules at chest CT was best represented by an exponential model compared with the other tested models. This justifies the use of volume doubling time for the growth assessment of these nodules. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Kuriyama and Yanagawa in this issue.