Female and underrepresented minority representation in radiology

RATIONAL AND OBJECTIVE

Diversity, equity, inclusion, and representation in various sectors have garnered increasing attention in the past two decades, including healthcare. In this report we investigate representation of females and underrepresented minorities (URM) in the field of radiology and asses for significant growth trends in representation in residency training programs in the United States.

MATERIALS AND METHODS

De-identified trainee demographic information for active radiology trainees from 2016 to 2021 was queried using the Accreditation Council for Graduate Medical Education (ACGME), and new radiology trainees using the National Resident Matching Program (NRMP)'s Main Residency Match Data and Reports databooks.

RESULTS

In 2021 females represented 26.7% of DR residency trainees and 22% of IR integrated trainees. In the same year URM trainees represented 11.3% of trainees and 8.7% of IR integrated trainees. From 2017 to 2021, diagnostic radiology had a compound average growth rate (CAGR) 1% (p <0.01) of female representation and 1.12% (p<0.01) of URM representation.

CONCLUSION

This study quantifies female and underrepresented minority representation among radiology trainees for diagnostic radiology and radiology subspecialities, identifying modest uptrends in representation within both demographics.

3.0-T MR-guided transgluteal in-bore-targeted prostate biopsy under local anesthesia in patients without rectal access: a single-institute experience and review of literature

PURPOSE

To describe the technique and evaluate the performance of MRI-guided transgluteal in-bore-targeted biopsy of the prostate gland under local anesthesia in patients without rectal access.

METHODS

Ten men (mean age, 69 (range 57-86) years) without rectal access underwent 13 MRI-guided transgluteal in-bore-targeted biopsy of the prostate gland under local anesthesia. All patients underwent mp-MRI at our institute prior to biopsy. Three patients had prior US-guided transperineal biopsy which was unsuccessful in one, negative in one, and yielded GG1 (GS6) PCa in one. Procedure time, complications, histopathology result, and subsequent management were recorded.

RESULTS

Median interval between rectal surgery and presentation with elevated PSA was 12.5 years (interquartile range (IQR) 25-75, 8-36.5 years). Mean PSA was 11.9 (range, 4.8 -59.0) ng/ml and PSA density was 0.49 (0.05 -3.2) ng/ml/ml. Distribution of PI-RADS v2.0/2.1 scores of the targeted lesions were PI-RADS 5-3; PI-RADS 4-6; and PI-RADS 3-1. Mean lesion size was 1.5 cm (range, 1.0-3.6 cm). Median interval between MRI and biopsy was 5.5 months (IQR 25-75, 1.5-9 months). Mean procedure time was 47.4 min (range, 29-80 min) and the number of cores varied between 3 and 5. Of the 13 biopsies, 4 yielded clinically significant prostate cancer (csPca), with a Gleason score ≥ 7, 1 yielded insignificant prostate cancer (Gleason score = 6), 7 yielded benign prostatic tissue, and one was technically unsuccessful. 3/13 biopsies were repeat biopsies which detected csPCa in 2 out of the 3 patients. None of the patients had biopsy-related complication. Biopsy result changed management to radiation therapy with ADT in 2 patients with the rest on active surveillance.

CONCLUSION

MRI-guided transgluteal in-bore-targeted biopsy of the prostate gland under local anesthesia is feasible in patients without rectal access.

Multi-scale statistical deformation based co-registration of prostate MRI and post-surgical whole mount histopathology

BACKGROUND

Accurate delineations of regions of interest (ROIs) on multi-parametric magnetic resonance imaging (mpMRI) are crucial for development of automated, machine learning-based prostate cancer (PCa) detection and segmentation models. However, manual ROI delineations are labor-intensive and susceptible to inter-reader variability. Histopathology images from radical prostatectomy (RP) represent the "gold standard" in terms of the delineation of disease extents, for example, PCa, prostatitis, and benign prostatic hyperplasia (BPH). Co-registering digitized histopathology images onto pre-operative mpMRI enables automated mapping of the ground truth disease extents onto mpMRI, thus enabling the development of machine learning tools for PCa detection and risk stratification. Still, MRI-histopathology co-registration is challenging due to various artifacts and large deformation between in vivo MRI and ex vivo whole-mount histopathology images (WMHs). Furthermore, the artifacts on WMHs, such as tissue loss, may introduce unrealistic deformation during co-registration.

PURPOSE

This study presents a new registration pipeline, MSERgSDM, a multi-scale feature-based registration (MSERg) with a statistical deformation (SDM) constraint, which aims to improve accuracy of MRI-histopathology co-registration.

METHODS

In this study, we collected 85 pairs of MRI and WMHs from 48 patients across three cohorts. Cohort 1 (D1), comprised of a unique set of 3D printed mold data from six patients, facilitated the generation of ground truth deformations between ex vivo WMHs and in vivo MRI. The other two clinically acquired cohorts (D2 and D3) included 42 patients. Affine and nonrigid registrations were employed to minimize the deformation between ex vivo WMH and ex vivo T2-weighted MRI (T2WI) in D1. Subsequently, ground truth deformation between in vivo T2WI and ex vivo WMH was approximated as the deformation between in vivo T2WI and ex vivo T2WI. In D2 and D3, the prostate anatomical annotations, for example, tumor and urethra, were made by a pathologist and a radiologist in collaboration. These annotations included ROI boundary contours and landmark points. Before applying the registration, manual corrections were made for flipping and rotation of WMHs. MSERgSDM comprises two main components: (1) multi-scale representation construction, and (2) SDM construction. For the SDM construction, we collected N = 200 reasonable deformation fields generated using MSERg, verified through visual inspection. Three additional methods, including intensity-based registration, ProsRegNet, and MSERg, were also employed for comparison against MSERgSDM.

RESULTS

Our results suggest that MSERgSDM performed comparably to the ground truth (p > 0.05). Additionally, MSERgSDM (ROI Dice ratio = 0.61, landmark distance = 3.26 mm) exhibited significant improvement over MSERg (ROI Dice ratio = 0.59, landmark distance = 3.69 mm) and ProsRegNet (ROI Dice ratio = 0.56, landmark distance = 4.00 mm) in local alignment.

CONCLUSIONS

This study presents a novel registration method, MSERgSDM, for mapping ex vivo WMH onto in vivo prostate MRI. Our preliminary results demonstrate that MSERgSDM can serve as a valuable tool to map ground truth disease annotations from histopathology images onto MRI, thereby assisting in the development of machine learning models for PCa detection on MRI.

Hospital payment systems and physician reimbursement: A primer for radiology residents

Prior to practicing independently, radiology trainees spend considerable time and energy to learn and understand the practice of radiology. However, upon graduation trainees are often deficient in understanding the business of hospitals and the structure of reimbursement. Specifically, the workflow of relative value units (RVUs) and its impact on practice of radiology after completing training. In this manuscript, we provide a resource for trainees to understand the workflow of physician reimbursement. This article includes information on the mixed model healthcare structure of the United States and two government programs that influence reimbursement: Diagnosis-Related Groups (DRG) and Hospital Value-Based Purchasing (HVBP) programs. Furthermore, we explain the method by which the Center of Medicare and Medicate Service's (CMS) reimburses physicians via the Medicare Physician Fee Schedule (MPFS) using the Resource Based Relative Value Scale. Understanding the structure of these payments along with the challenges and current landscape of radiology reimbursement will help new radiologists prior to seeking employment where reimbursements are integral to contract expectations.

Analysis of ChatGPT publications in radiology: Literature so far

OBJECTIVE

To perform a detailed qualitative and quantitative analysis of the published literature on ChatGPT and radiology in the nine months since its public release, detailing the scope of the work in the short timeframe.

METHODS

A systematic literature search was carried out of the MEDLINE, EMBASE databases through August 15, 2023 for articles that were focused on ChatGPT and imaging/radiology. Articles were classified into original research and reviews/perspectives. Quantitative analysis was carried out by two experienced radiologists using objective scoring systems for evaluating original and non-original research.

RESULTS

51 articles were published involving ChatGPT and radiology/imaging dating from 26 Jan 2023 to the last article published on 14 Aug 2023. 23 articles were original research while the rest included reviews/perspectives or brief communications. For quantitative analysis scored by two readers, we included 23 original research and 17 non-original research articles (after excluding 11 letters as responses to previous articles). Mean score for original research was 3.20 out of 5 (across five questions), while mean score for non-original research was 1.17 out of 2 (across six questions). Mean score grading performance of ChatGPT in original research was 3.20 out of five (across two questions).

DISCUSSION

While it is early days for ChatGPT and its impact in radiology, there has already been a plethora of articles talking about the multifaceted nature of the tool and how it can impact every aspect of radiology from patient education, pre-authorization, protocol selection, generating differentials, to structuring radiology reports. Most articles show impressive performance of ChatGPT which can only improve with more research and improvements in the tool itself. There have also been several articles which have highlighted the limitations of ChatGPT in its current iteration, which will allow radiologists and researchers to improve these areas.

Assessing appropriate responses to ACR urologic imaging scenarios using ChatGPT and Bard

Artificial intelligence (AI) has recently become a trending tool and topic regarding productivity especially with publicly available free services such as ChatGPT and Bard. In this report, we investigate if two widely available chatbots chatGPT and Bard, are able to show consistent accurate responses for the best imaging modality for urologic clinical situations and if they are in line with American College of Radiology (ACR) Appropriateness Criteria (AC). All clinical scenarios provided by the ACR were inputted into ChatGPT and Bard with result compared to the ACR AC and recorded. Both chatbots had an appropriate imaging modality rate of of 62% and no significant difference in proportion of correct imaging modality was found overall between the two services (p>0.05). The results of our study found that both ChatGPT and Bard are similar in their ability to suggest the most appropriate imaging modality in a variety of urologic scenarios based on ACR AC criteria. Nonetheless, both chatbots lack consistent accuracy and further development is necessary for implementation in clinical settings. For proper use of these AI services in clinical decision making, further developments are needed to improve the workflow of physicians.

Disparities in Mortality Trends of Breast Cancer by Racial and Ethnic Status in the United States

BACKGROUND AND AIM

Breast cancer is the most commonly diagnosed malignancy for women and is a leading cause of mortality in women worldwide and in the United States. Recently, new interventions have been developed to improve its prognosis. The aim of this study was to assess the impact of new therapies on racial and ethnic groups in the United States for demographic-based disparities. We assessed the impact of these developments from 1999 to 2020 on age adjusted mortality rate (AAMR), mortality rate trend from 1999 to 2020, average annual percent change (AAPC), and temporal trends, by annual percent change (APC) in the United States for various demographic groups.

PATIENTS AND METHODS

We queried the CDC Wonder database to retrieve mortality rates by race and ethnic group from 1999 to 2020 with breast malignancy as a contributing cause of death.

RESULTS

Between 1999 to 2020, all racial groups presented a significant overall decline in mortality rates: AI/AN [AAPC, -1.6% (95% CI=-2.2% to -1.0%); p<0.01], AAPI [AAPC, -0.5% (95% CI=-1.00% to -0.1%); p<0.01], Black/African American [AAPC, -1.4% (95% CI=-1.6% to -1.2%); p<0.01], and the white population [AAPC, -1.7% (95% CI=-1.8% to -1.5%); p<0.01]. The Black/African American population had a significant lower rate of decline compared to the white population (p<0.01) and Hispanic/Latinx populations had a lower rate of decline compared to those who are non-Hispanic/Latinx (p<0.01).

CONCLUSION

We found that Black/African American population had a significant lower rate of decline compared to the white population and Hispanic/Latinx populations had a lower rate of decline compared to those who are non-Hispanic/Latinx. These differences in mortality trend rates in breast cancer emphasize the need for targeted interventions and resources tailored to specific demographic needs.

Spatiotemporal knowledge teacher-student reinforcement learning to detect liver tumors without contrast agents

Detecting Liver tumors without contrast agents (CAs) has shown great potential to advance liver cancer screening. It enables the provision of a reliable liver tumor-detecting result from non-enhanced MR images comparable to the radiologists' results from CA-enhanced MR images, thus eliminating the high risk of CAs, preventing an experience gap between radiologists and simplifying clinical workflows. In this paper, we proposed a novel spatiotemporal knowledge teacher-student reinforcement learning (SKT-RL) as a safe, speedy, and inexpensive contrast-free technology for liver tumor detection. Our SKT-RL builds a teacher-student framework to realize the exploring of explicit liver tumor knowledge from a teacher network on clear contrast-enhanced images to guide a student network to detect tumors from non-enhanced images directly. Importantly, our STK-RL enables three novelties in aspects of construction, transferring, and optimization to tumor knowledge to improve the guide effect. (1) A new spatiotemporal ternary knowledge set enables the construction of accurate knowledge that allows understanding of DRL's behavior (what to do) and reason (why to do it) behind reliable detection within each state and between their related historical states. (2) A novel pixel momentum transferring strategy enables detailed and controlled knowledge transfer ability. It transfers knowledge at a pixel level to enlarge the explorable space of transferring and control how much knowledge is transferred to prevent over-rely of the student to the teacher. (3) A phase-trend reward function designs different evaluations according to different detection phases to optimal for each phase in high-precision but also allows reward trend to constraint the evaluation to improve stability. Comprehensive experiments on a generalized liver tumor dataset with 375 patients (including hemangiomas, hepatocellular carcinoma, and normal controls) show that our novel SKT-RL attains a new state-of-the-art performance (improved precision by at least 4% when comparing the six recent advanced methods) in the task of liver tumor detection without CAs. The results proved that our SKT-DRL has greatly promoted the development and deployment of contrast-free liver tumor technology.

Pharmaceutical Industry Payments to Diagnostic Radiologists

The Physician Payments Sunshine Act 2010 (PPSA) mandates that all industry payments to physicians be publicly recorded in order to increase transparency of industry-physician relationships. To assess industry relationships with diagnostic radiologists (DR), and to compare these relationships with those of oncology, a more directly medicine related field. We queried the Open payments database to collect industry payments data for both DR and oncology. Data was analyzed using IBM SPSS software, significance is set at P < 0.05. We found that from 2012 to 2020, a total of 178,957 industry payments to DR were made via cash in-kind items and services. The average value of a cash payment was $1529, and $223 for in-kind. In addition, we found that pharmaceutical industries contribute a large portion of industry payments to DR, with the top 3 payors being Merk Sharp and Dohme Corporation followed by Hologic and Pfizer. When comparing payments between DR and oncology, the latter received more total payments for each year until 2019, where after DR physicians began to receive more total value in payments. In addition, DR physicians received on average a 10 times greater payment per transaction. From 2012 to 2021, DR physicians have had a stable trend of number of payments received, but an increase in average value per payment. From 2019 to 2021, oncologists have observed a downtrend in total value of payments, while DR physicians are observing a steep uptrend. This investigation assesses industry payments to DR physicians with context added from those of oncology. The results show that pharmaceutical industry payors are significantly involved in radiology and DR physicians are receiving greater value of payments from industry sponsors. By increasing transparency of industry relationships and understanding the nature of these relationships, the impact of industry on patient care can be better understood.

Delta radiomic patterns on serial bi-parametric MRI are associated with pathologic upgrading in prostate cancer patients on active surveillance: preliminary findings

Objective

The aim of this study was to quantify radiomic changes in prostate cancer (PCa) progression on serial MRI among patients on active surveillance (AS) and evaluate their association with pathologic progression on biopsy.

Methods

This retrospective study comprised N = 121 biopsy-proven PCa patients on AS at a single institution, of whom N = 50 at baseline conformed to the inclusion criteria. ISUP Gleason Grade Groups (GGG) were obtained from 12-core TRUS-guided systematic biopsies at baseline and follow-up. A biopsy upgrade (AS+) was defined as an increase in GGG (or in number of positive cores) and no upgrade (AS-) was defined when GGG remained the same during a median period of 18 months. Of N = 50 patients at baseline, N = 30 had MRI scans available at follow-up (median interval = 18 months) and were included for delta radiomic analysis. A total of 252 radiomic features were extracted from the PCa region of interest identified by board-certified radiologists on 3T bi-parametric MRI [T2-weighted (T2W) and apparent diffusion coefficient (ADC)]. Delta radiomic features were computed as the difference of radiomic feature between baseline and follow-up scans. The association of AS+ with age, prostate-specific antigen (PSA), Prostate Imaging Reporting and Data System (PIRADS v2.1) score, and tumor size was evaluated at baseline and follow-up. Various prediction models were built using random forest (RF) classifier within a threefold cross-validation framework leveraging baseline radiomics (Cbr), baseline radiomics + baseline clinical (Cbrbcl), delta radiomics (CΔr), delta radiomics + baseline clinical (CΔrbcl), and delta radiomics + delta clinical (CΔrΔcl).

Results

An AUC of 0.64 ± 0.09 was obtained for Cbr, which increased to 0.70 ± 0.18 with the integration of clinical variables (Cbrbcl). CΔr yielded an AUC of 0.74 ± 0.15. Integrating delta radiomics with baseline clinical variables yielded an AUC of 0.77 ± 0.23. CΔrΔclresulted in the best AUC of 0.84 ± 0.20 (p < 0.05) among all combinations.

Conclusion

Our preliminary findings suggest that delta radiomics were more strongly associated with upgrade events compared to PIRADS and other clinical variables. Delta radiomics on serial MRI in combination with changes in clinical variables (PSA and tumor volume) between baseline and follow-up showed the strongest association with biopsy upgrade in PCa patients on AS. Further independent multi-site validation of these preliminary findings is warranted.

Emergency department imaging utilization of cancer patients treated with bevacizumab: single-institution 8-year experience

PURPOSE

This study aims to highlight the presentations, imaging, and clinical outcomes of cancer patients presenting to the emergency department (ED) while receiving bevacizumab (Avastin) therapy.

METHODS

Our retrospective study was based on data from a single institution to identify cancer patients who presented acutely to the ED between 2014 and 2021 within 3 months of beginning bevacizumab who subsequently received diagnostic imaging with CT, MRI, ultrasound, and/or nuclear medicine ventilation/perfusion (VQ) scans. Data gathered included presenting symptoms grouped by body system, imaging impressions, and clinical outcomes, including hospitalization and discontinuation of bevacizumab after each ED visit. Imaging examinations and patient charts were reviewed by a team of fellowship-trained radiologists, radiology residents, and medical students.

RESULTS

A total of 84 patients who presented to the ED were included for analysis. This included 32 (38.1%) males and 52 (61.9%) females, with a mean age of 61.2 years and an age range of 29-91 years. Neurological symptoms were the most common presenting symptoms, followed by abdominal symptoms and respiratory symptoms. Head imaging with CT and MRI was the most common imaging ordered with 55 total examinations, followed by abdominal imaging with 37 CT abdomen/pelvis (A/P) examinations, and then CT chest imaging with 22 examinations. Imaging revealed a serious adverse drug reaction in 21 (25.0%) patients, disease progression in 19 (22.6%), and no acute imaging findings in 44 (52.4%) patients. Imaging diagnoses were significantly associated with treatment planning, with a positive determination of bevacizumab-related serious adverse reaction on imaging leading to discontinuation of bevacizumab (p = 0.001).

CONCLUSION

Multimodality imaging was a commonly used assessment tool for cancer patients receiving bevacizumab who presented to the ED. Imaging played a crucial role in diagnosis in these patients, especially of treatment-related serious adverse reactions and disease progression. Positive imaging findings of serious adverse reactions affected patient management including discontinuation of bevacizumab.

Novel radiomic analysis on bi-parametric MRI for characterizing differences between MR non-visible and visible clinically significant prostate cancer

Background

around one third of clinically significant prostate cancer (CsPCa) foci are reported to be MRI non-visible (MRI─).

Objective

To quantify the differences between MR visible (MRI+) and MRI^─ CsPCa using intra- and peri-lesional radiomic features on bi-parametric MRI (bpMRI).

Methods

This retrospective and multi-institutional study comprised 164 patients with pre-biopsy 3T prostate multi-parametric MRI from 2014 to 2017. The MRI^─ CsPCa referred to lesions with PI-RADS v2 score < 3 but ISUP grade group > 1. Three experienced radiologists were involved in annotating lesions and PI-RADS assignment. The validation set (D_v) comprised 52 patients from a single institution, the remaining 112 patients were used for training (D_t). 200 radiomic features were extracted from intra-lesional and peri-lesional regions on bpMRI.Logistic regression with least absolute shrinkage and selection operator (LASSO) and 10-fold cross-validation was applied on D_t to identify radiomic features associated with MRI^─ and MRI⁺ CsPCa to generate corresponding risk scores R^MRI─ and R^MRI+. R_bpMRI was further generated by integrating R^MRI─ and R^MRI+. Statistical significance was determined using the Wilcoxon signed-rank test.

Results

Both intra-lesional and peri-lesional bpMRI Haralick and CoLlAGe radiomic features were significantly associated with MRI^─ CsPCa (p < 0.05). Intra-lesional ADC Haralick and CoLlAGe radiomic features were significantly different among MRI^─ and MRI⁺ CsPCa (p < 0.05). R_bpMRI yielded the highest AUC of 0.82 (95 % CI 0.72-0.91) compared to AUCs of R^MRI+ 0.76 (95 % CI 0.63-0.89), and PI-RADS 0.58 (95 % CI 0.50-0.72) on D_v. R_bpMRI correctly reclassified 10 out of 14 MRI^─ CsPCa on D_v.

Conclusion

Our preliminary results demonstrated that both intra-lesional and peri-lesional bpMRI radiomic features were significantly associated with MRI^─ CsPCa. These features could assist in CsPCa identification on bpMRI.

Development and Implementation of Integrated Radiologist-Speech Pathologist Report for Modified Barium Swallow Study: Experience at a Multi-hospital Single Health Care System

Dysphagia, or a disorder of swallowing, is very common and is reported in 1 out of 25 adults with approximately 1 million new cases per year in the United States alone. This also disproportionately impacts elderly patients, with a prevalence of 17%. Patients with dysphagia may have severe clinical complications such as starvation, dehydration, and airway obstruction- which may further increase mortality. Hence, timely and accurate diagnosis of dysphagia is hence crucial in management considerations. The gold standard for evaluating and diagnosing dysphagia is a modified barium swallow study (MBSS). The study is typically performed as a collaborative effort between a speech language pathologist (SLP) and a radiologist, who bring their individual skill sets to the table. Current MBSS reporting involves separately dictated and interpreted reports from the SLP and radiologist. In this paper, we elucidate our experience in a multi-institutional healthcare system wherein we have devised a single, integrated report for MBSS, which involves collaborative effort between SLP and the radiologist. We weight the advantages and disadvantages of unified reporting, the challenges of implementing it in a large healthcare system, and note how it can help improve efficiency and deliver unified patient care. We hope that this would be a template for other institutions as well as improve standardization of reporting techniques.

Thymoquinone Plus Immunotherapy in Extra-Pulmonary Neuroendocrine Carcinoma: Case Series for a Novel Combination

BACKGROUND

Neuroendocrine neoplasms (NENs) are a heterogeneous group of cancers that had a significant increase in annual incidence in the last decade. They can be divided into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Poorly differentiated NECs are aggressive forms of cancers with limited therapeutic options. The first line treatment of metastatic poorly differentiated NECs is similar to small cell lung cancer, with cytotoxic chemotherapy (etoposide plus platinum). Patients who progress have limited therapeutic options and poor overall survival, calling for other novel agents to combat this deadly disease. Therefore, in this article, we summarized the effects of a novel component, Thymoquinone (TQ, C10H12O2), which is the main bioactive component of the black seed (Nigella sativa, Ranunculaceae family), plus immunotherapy in case series of patients with refractory metastatic extra-pulmonary NEC (EP-NEC) and one case of mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN).

METHODS

We report the effect of TQ plus dual immune checkpoint inhibitors (nivolumab plus ipilimumab) in four patients with poorly differentiated gastrointestinal Ep-NEC and MiNEN who progressed on cytotoxic chemotherapy.

RESULTS

This is the first case series to report the clinical activity of TQ plus dual immune checkpoint inhibitors (nivolumab plus ipilimumab) in patients with refractory metastatic EP-NEC. The four patients showed benefits with the combined regimen TQ plus dual ICPIs with durable response and exceeded the two years of progression-free survival. None of the four patients experienced significant toxicity, and all of them showed improvement in quality of life.

CONCLUSION

The reported clinical courses suggest that combined TQ plus ICPIs is a potential promising regimen for refractory EP-NEC and MiNEN that deserves further prospective investigation.

A Decade of Success in Melanoma Immunotherapy and Targeted Therapy: What Every Radiologist Should Know

ABSTRACT

Treatment strategies for malignant melanoma have rapidly evolved over the past decade. Because of its propensity to develop advanced stage and metastatic disease, melanoma has contributed to the majority of mortalities among patients with skin cancer. The development of novel therapeutics such as immunotherapy and targeted molecular therapies has revolutionized the treatment of patients with advanced stage and metastatic malignant melanoma. Immune checkpoint inhibitors, BRAF/MEK inhibitors, and other revolutionary therapies have demonstrated remarkable success in the treatment of this common malignancy. Along with these advancements in systemic therapies, imaging has continued to play a critical role in the diagnosis and follow-up of patients with malignant melanoma. As the use of these novel therapies continues to expand, knowledge of the evolving therapeutic landscape of melanoma is becoming critical for radiologists. In this review, we provide a primer for radiologists outlining the evolution of immunotherapy and targeted therapy in the treatment of melanoma. We discuss the critical role of imaging in evaluation of treatment response, including a summary of current imaging response guidelines. Last, we summarize the essential role of imaging in the evaluation of potential adverse events seen in patients with malignant melanoma undergoing treatment with immune checkpoint inhibitors.

Prostate Surface Distension and Tumor Texture Descriptors From Pre-Treatment MRI Are Associated With Biochemical Recurrence Following Radical Prostatectomy: Preliminary Findings

Objective

To derive and evaluate the association of prostate shape distension descriptors from T2-weighted MRI (T2WI) with prostate cancer (PCa) biochemical recurrence (BCR) post-radical prostatectomy (RP) independently and in conjunction with texture radiomics of PCa.

Methods

This retrospective study comprised 133 PCa patients from two institutions who underwent 3T-MRI prior to RP and were followed up with PSA measurements for ≥3 years. A 3D shape atlas-based approach was adopted to derive prostate shape distension descriptors from T2WI, and these descriptors were used to train a random forest classifier (C_S) to predict BCR. Texture radiomics was derived within PCa regions of interest from T2WI and ADC maps, and another machine learning classifier (C_R) was trained for BCR. An integrated classifier C_S+R was then trained using predictions from C_S and C_R. These models were trained on D₁ (N = 71, 27 BCR+) and evaluated on independent hold-out set D₂ (N = 62, 12 BCR+). C_S+R was compared against pre-RP, post-RP clinical variables, and extant nomograms for BCR-free survival (bFS) at 3 years.

Results

C_S+R resulted in a higher AUC (0.75) compared to C_R (0.70, p = 0.04) and C_S (0.69, p = 0.01) on D₂ in predicting BCR. On univariable analysis, C_S+R achieved a higher hazard ratio (2.89, 95% CI 0.35–12.81, p < 0.01) compared to other pre-RP clinical variables for bFS. C_S+R, pathologic Gleason grade, extraprostatic extension, and positive surgical margins were associated with bFS (p < 0.05). C_S+R resulted in a higher C-index (0.76 ± 0.06) compared to CAPRA (0.69 ± 0.09, p < 0.01) and Decipher risk (0.59 ± 0.06, p < 0.01); however, it was comparable to post-RP CAPRA-S (0.75 ± 0.02, p = 0.07).

Conclusions

Radiomic shape descriptors quantifying prostate surface distension complement texture radiomics of prostate cancer on MRI and result in an improved association with biochemical recurrence post-radical prostatectomy.

Efficacy of Immune Checkpoint Inhibitors against Advanced or Metastatic Neuroendocrine Neoplasms: A Systematic Review and Meta-Analysis

We performed a systematic review and meta-analysis of the treatment efficacy of immune checkpoint inhibitors (ICIs) in advanced/metastatic neuroendocrine neoplasms (NENs). MEDLINE and EMBASE were searched to identify studies that provide data on treatment response and/or survival outcomes of advanced/metastatic NEN patients treated with ICIs. The overall response rate (ORR) was pooled using a random-effects model. Meta-regression was performed to explore factors influencing the ORR. Individual patient data (IPD) meta-analysis of survival was performed using stratified Cox regression. Ten studies (464 patients) were included. The overall pooled ORR was 15.5% (95% confidence interval (CI), 9.5-24.3%), and it varied according to the primary site (thoracic, 24.7%; gastro-entero-pancreatic, 9.5%), tumor differentiation (poorly differentiated, 22.7%; well-differentiated, 10.4%), and drug regimen (combination, 25.3%; monotherapy, 10.1%). All these variables significantly influenced the ORR. Tumor differentiation was associated with both overall survival and progression-free survival (hazard ratio of poorly differentiated tumors, 4.2 (95% CI, 2.0-8.7) and 2.6 (95% CI, 1.6-4.4), respectively). Thus, the treatment efficacy of ICIs for advanced/metastatic NENs varied according to primary site, tumor differentiation, and drug regimen. Poorly differentiated NENs showed a better ORR than well-differentiated NENs but had a negative impact on survival.

Past, Present, and Future of Serum Tumor Markers in Management of Ovarian Cancer: A Guide for the Radiologist

The ability to accurately detect early ovarian cancer and subsequently monitor treatment response is essential to improving survival for patients with ovarian malignancies. Several serum tumor markers (STMs)-including cancer antigen 125 (CA-125), human epididymis protein 4 (HE4), cancer antigen 19-9 (CA 19-9), and carcinoembryonic antigen (CEA)-have been used as a noninvasive method of identifying ovarian cancer in conjunction with imaging. Although current guidelines do not recommend use of STMs as screening tools for ovarian cancer, these markers have clinical utility in both diagnosis and surveillance for women with ovarian cancer. CA-125 is the most commonly used STM; its level may be elevated in several types of ovarian cancer, including epithelial cell tumors, carcinosarcoma, teratomas, and secondary ovarian malignancies. An elevated level of CA 19-9 is associated with clear cell tumors, teratomas, and secondary malignancies. CEA is most commonly associated with mucinous ovarian cancers. Finally, HE4 is being increasingly used to identify certain subtypes of epithelial ovarian cancers, particularly serous and endometrioid tumors. Diagnosis of ovarian cancers relies on a combination of CA-125 levels and US findings, which include a large adnexal mass or high-risk features, including septa and increased vascularity. CT is preferred for staging and is used along with PET and STM monitoring for surveillance. Increasingly, MRI is being used to characterize ovarian lesions that are indeterminate at US or CT. The future of STM testing involves development of "liquid biopsies," in which plasma samples are analyzed for evidence of tumors, including circulating tumor DNA or tumor cells and tumor micro-RNA. When combined with traditional imaging techniques, liquid biopsies may lead to earlier diagnosis and improved survival. An invited commentary by Shinagare is available online. ^©RSNA, 2021.

Trends in Medicare Part B Payments and Utilization for Imaging Services Between 2009 and 2019

BACKGROUND

In 2019, the total National Healthcare Expenditure (NHE) reached $3.8 trillion, or nearly 20% of the total Gross Domestic Product. This represents a 4-fold increase in its Gross Domestic Product share since 1960. Given the magnitude and growth of such expenditures, healthcare cost containment is central to the country's financial sustainability. Moreover, as Medicare represents nearly 20% of the total NHE, it is a primary target for piloting, implementing and scaling initiatives that reduce expenditures.

OBJECTIVE

To assess trends in Medicare Physician Fee Schedule for Service (Part B) payments and utilization for Imaging relative to other services from 2009 through 2019.

MATERIALS AND METHODS

We conducted a retrospective observational study of annual expenditures and utilization of imaging services using data from Centers for Medicare and Medicaid Services Medicare Part B. Data was grouped according to the Berenson-Eggers Type of Service Classification. The values were adjusted for inflation and we calculated the annual changes and the compound annual growth rates and the price elasticity of supply.

RESULTS

For the 10-year period, Imaging represented on average 8% of the total Medicare Part B expenditures, an equivalent of 1.4% of total Medicare expenditures or 0.05% of the NHE. While NHE, overall Medicare and overall Part B had positive growth rates of total expenditures, Imaging did not. Moreover, Imaging had the most negative CAGR compared to all other categories, including Drugs, Procedures, Evaluation and Management and Durable Medical Equipment.

CONCLUSION

Imaging did not contribute to the increase in Medicare Part B expenditures, and it might have been disproportionately affected by cost containment policies.

An integrated nomogram combining deep learning, Prostate Imaging-Reporting and Data System (PI-RADS) scoring, and clinical variables for identification of clinically significant prostate cancer on biparametric MRI: a retrospective multicentre study

Background

Biparametric MRI (comprising T2-weighted MRI and apparent diffusion coefficient maps) is increasingly being used to characterise prostate cancer. Although previous studies have combined Prostate Imaging–Reporting & Data System (PI-RADS)-based MRI findings with routinely available clinical variables and with deep learning-based imaging predictors, respectively, for prostate cancer risk stratification, none have combined all three. We aimed to construct an integrated nomogram (referred to as ClaD) combining deep learning-based imaging predictions, PI-RADS scoring, and clinical variables to identify clinically significant prostate cancer on biparametric MRI.

Methods

In this retrospective multicentre study, we included patients with prostate cancer, with histopathology or biopsy reports and a screening or diagnostic MRI scan in the axial view, from four cohorts in the USA (from University Hospitals Cleveland Medical Center, Icahn School of Medicine at Mount Sinai, Cleveland Clinic, and Long Island Jewish Medical Center) and from the PROSTATEx Challenge dataset in the Netherlands. We constructed an integrated nomogram combining deep learning, PI-RADS score, and clinical variables (prostate-specific antigen, prostate volume, and lesion volume) using multivariable logistic regression to identify clinically significant prostate cancer on biparametric MRI. We used data from the first three cohorts to train the nomogram and data from the remaining two cohorts for independent validation. We compared the performance of our ClaD integrated nomogram with that of integrated nomograms combining clinical variables with either the deep learning-based imaging predictor (referred to as DIN) or PI-RADS score (referred to as PIN) using area under the receiver operating characteristic curves (AUCs). We also compared the ability of the nomograms to predict biochemical recurrence on a subset of patients who had undergone radical prostatectomy. We report cross-validation AUCs as means for the training set and used AUCs with 95% CIs to assess the performance on the test set. The difference in AUCs between the models were tested for statistical significance using DeLong’s test. We used log-rank tests and Kaplan-Meier curves to analyse survival.

Findings

We investigated 592 patients (823 lesions) with prostate cancer who underwent 3T multiparametric MRI at five hospitals in the USA between Jan 8, 2009, and June 3, 2017. The training data set consisted of 368 patients from three sites (the PROSTATEx Challenge cohort [n=204], University Hospitals Cleveland Medical Center [n=126], and Icahn School of Medicine at Mount Sinai [n=38]), and the independent validation data set consisted of 224 patients from two sites (Cleveland Clinic [n=151] and Long Island Jewish Medical Center [n=73]). The ClaD clinical nomogram yielded an AUC of 0·81 (95% CI 0·76–0·85) for identification of clinically significant prostate cancer in the validation data set, significantly improving performance over the DIN (0·74 [95% CI 0·69–0·80], p=0·0005) and PIN (0·76 [0·71–0·81], p<0·0001) nomograms. In the subset of patients who had undergone radical prostatectomy (n=81), the ClaD clinical nomogram resulted in a significant separation in Kaplan-Meier survival curves between patients with and without biochemical recurrence (HR 5·92 [2·34–15·00], p=0·044), whereas the DIN (1·22 [0·54–2·79], p=0·65) and PIN nomograms did not (1·30 [0·62–2·71], p=0·51).

Interpretation

Risk stratification of patients with prostate cancer using the integrated ClaD nomogram could help to identify patients with prostate cancer who are at low risk, very low risk, and favourable intermediate risk, who might be candidates for active surveillance, and could also help to identify patients with lethal prostate cancer who might benefit from adjuvant therapy.

Funding

National Cancer Institute of the US National Institutes of Health, National Institute for Biomedical Imaging and Bioengineering, National Center for Research Resources, US Department of Veterans Affairs Biomedical Laboratory Research and Development Service, US Department of Defense, US National Institute of Diabetes and Digestive and Kidney Diseases, The Ohio Third Frontier Technology Validation Fund, Case Western Reserve University, Dana Foundation, and Clinical and Translational Science Collaborative.

Impact of BRAF mutations on outcomes in metastatic melanoma with central nervous system metastases treated with immune checkpoint inhibitors

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Background: Half of patients (pts) with melanoma (mel) develop central nervous system (CNS) metastases (mets), leading to death in over 90% in the pre-immune checkpoint inhibitor (ICI) era. Overall survival (OS) has improved in the ICI era for those with CNS mets, yet the association of survival with ICI treatment for those with tumors harboring genomic variants (var) remains unclear. Methods: We retrospectively reviewed our electronic medical records to identify pts with mel and CNS mets who received ICI from 2010 to 2018. Treatment history, systemic and CNS responses, and genomic data were recorded. Genomic var were categorized as BRAFV600E (BRAF), NRAS, cKIT, other var, and no var. Concurrent RT (CRT) was defined as RT to CNS mets within 30 days of ICI. OS was calculated from date of first ICI or RT to date of death or last follow up, and comparison analyses made using Kaplan-Meier estimate. Fisher's exact or Chi-squared tests were used to compare categorical variables and Wilcoxon or Kruskal-Wallis tests to compare continuous variables. A two-sided p-value of < 0.05 was considered statistically significant. Results: A total of 49 pts were identified; 37 had var results available. BRAFV600E was the most common var identified (32%), followed by NRAS (19%), cKIT (5%), and other (5%); 38% had no var. BRAFV600K was not identified. Pts with BRAF had lower rates of CNS progression on ICI at 3 and 6 months than all other pts (17% vs 50%, p< 0.01 and 12.5% vs 40%, p< 0.01, respectively). Of 38 pts (10 BRAF) who had CNS mets at the start of ICI, 6-month OS was 50% in pts with BRAF, compared to 0% in pts with non-BRAF var ( p= 0.01) and 36% in pts with no var ( p= 0.7). 4 of the 10 pts with BRAF who had CNS mets at start of ICI received BRAF-targeted therapy after ICI. On ICI, only 30% of pts with BRAF developed new CNS mets, compared to 57% of all other pts ( p= 0.08). Pts who developed new CNS mets on ICI had worse OS than pts who did not (median OS (mOS) 314 days vs 662 days, p= 0.04). A majority of pts (55%) received anti-CTLA4 monotherapy as first ICI, and 39% received anti-CTLA4 plus anti-PD1. Pts with BRAF were just as likely to receive dual anti-CTLA4/PD-1 as pts without BRAF (33% vs 40%, p= 0.74). 40 pts underwent RT for CNS mets, of whom 22 received CRT. There was no difference in mOS between pts who received CRT and non-concurrent RT/no RT (468 days vs 314 days, p= 0.8). Rates of CRT between pts with BRAF and pts without BRAF were similar ( p> 0.9), and there was no difference in mOS between these groups (400 days vs 536 days, p= 0.9). Conclusions: Pts with BRAF-mutated mel with CNS mets receiving ICI had lower rates of progression in CNS and improved OS compared to other var. CRT was not associated with improved survival over non-concurrent RT. There has been significant improvement in OS of pts with mel CNS mets in the era of ICI and additional studies are warranted to understand the biology of BRAF var and the host immune system response in the CNS.

Second Malignancies after Radiation Therapy: Update on Pathogenesis and Cross-sectional Imaging Findings

A wide spectrum of second cancers occur as late complications of radiation therapy (RT) used to treat various malignancies. In addition to the type and dose of radiation, lifestyle, environmental, and genetic factors are important to the development of second malignancies in cancer survivors. Typically, RT-induced malignancies (RTIMs) are biologically aggressive cancers with a variable period of 5-10 years for hematologic malignancies and 10-60 years for solid tumors between RT and the development of the second cancer. Although carcinomas and leukemias commonly develop after low-dose RT, sarcomas occur in tissues or organs that receive high-dose RT. Angiosarcomas and unclassified pleomorphic sarcomas are the two most common RT-associated sarcomas; other sarcomas include malignant peripheral nerve sheath tumors, leiomyosarcomas, osteosarcomas, chondrosarcomas, and dedifferentiated or pleomorphic liposarcomas. Select RTIMs show tumor genetic characteristics that allow accurate diagnosis. Nearly all cutaneous angiosarcomas after RT for breast cancer and 90% of RT-associated malignant peripheral nerve sheath tumors are characterized by MYC gene amplifications and loss of H3 K27me3 expression, respectively. Classic papillary thyroid carcinomas that develop after RT frequently harbor RET/PTC rearrangements and have a favorable prognosis, despite their advanced stage at patient presentation. Select RTIMs demonstrate characteristic imaging findings and typically develop in the prior radiation field. Imaging is essential to early diagnosis, characterization, localization, and staging of RTIMs. Familiarity of radiologists with the diverse spectrum of RTIMs is essential for early diagnosis and optimal management. An invited commentary by Shapiro is available online. ^©RSNA, 2021.

Considerations in imaging interpretations for colitis in critically ill patients during the COVID-19 era

OBJECTIVE

The study aims to demonstrate risk factors for colitis in intensive care unit patients with and without coronavirus disease 2019 (COVID-19).

METHODS

Retrospective review was performed to identify intensive care unit (ICU) patients with the diagnosis of COVID-19 with computed tomography (CT) between March 20 and December 31, 2020. ICU patients without COVID-19 diagnosis with CT between March 20 and May 10, 2020 were also identified. CT image findings of colitis or terminal ileitis as well as supportive treatment including ventilator, vasopressors, or extracorporeal membrane oxygenation (ECMO) were recorded. Statistical analysis was performed to determine if clinical factors differed in patients with and without positive CT finding.

RESULTS

Total 61 ICU patients were selected, including 32 (52%) COVID-19-positive patients and 29 (48%) non-COVID-19 patients. CT findings of colitis or terminal ileitis were identified in 27 patients (44%). Seventy-four percent of the patients with positive CT findings (20/27) received supportive therapies prior to CT, while 56% of the patients without abnormal CT findings (19/34) received supportive therapies. Vasopressor treatment was significantly associated with development of colitis and/or terminal ileitis (p = 0.04) and COVID-19 status was not significantly different between these groups (p = 0.07).

CONCLUSIONS

In our study, there was significant correlation between prior vasopressor therapy and imaging findings of colitis or terminal ileitis in ICU patients, independent of COVID-19 status. Our observation raises a possibility that the reported COVID-19-related severe gastrointestinal complications and potential poor outcome could have been confounded by underlying severe critically ill status, and warrants a caution in diagnosis of gastrointestinal complication.

Definition, Incidence, and Challenges for Assessment of Hyperprogressive Disease During Cancer Treatment With Immune Checkpoint Inhibitors: A Systematic Review and Meta-analysis

IMPORTANCE

Hyperprogressive disease (HPD) is a recognized pattern of rapid tumor progression during immune checkpoint inhibitor (ICI) treatment. Definitions of HPD have not been standardized, posing the risk of capturing different tumoral behaviors.

OBJECTIVES

To provide a systematic summary of definitions and the incidence of HPD in patients undergoing ICI treatment and discuss the challenges of current assessment of HPD.

DATA SOURCES

Articles that evaluated HPD published before March 3, 2020, were identified from MEDLINE and EMBASE.

STUDY SELECTION

Clinical trials and observational studies providing the incidence and definition of HPD from patients with cancer treated with ICIs.

DATA EXTRACTION AND SYNTHESIS

Factors included in the analysis comprised authors, year of publication, cancer type, ICI type, number of previous treatment lines, definition of HPD, time frame used to assess HPD, number of patients with HPD, onset of HPD, and prognosis of patients with HPD. Quantitative and qualitative syntheses for the incidence of HPD were performed.

MAIN OUTCOMES AND MEASURES

Definitions of HPD were categorized and the range of incidence of HPD was evaluated. Subgroup analysis on the incidence of HPD according to the category was performed and the challenges associated with current HPD assessment were evaluated.

RESULTS

Twenty-four studies with 3109 patients were analyzed. The incidence of HPD varied from 5.9% to 43.1%. The definitions were divided into 4 categories based on the calculation of tumor growth acceleration: tumor growth rate ratio (pooled incidence of HPD, 9.4%; 95% CI, 6.9%-12.0%), tumor growth kinetics ratio (pooled incidence, 15.8%; 95% CI, 8.0%-23.7%), early tumor burden increase (pooled incidence, 20.6%; 95% CI, 9.3%-31.8%), and combinations of the above (pooled incidence, 12.4%; 95% CI, 7.3%-17.5%). Hyperprogressive disease could be overestimated or underestimated if the assessment was limited to tumor growth rate or tumor growth kinetics ratio, target lesions, or response evaluation criteria in solid tumors (RECIST)-defined progressors, or if the assessment time frame conformed to RECIST. Study results on clinical outcome were heterogeneous on discriminating patients with HPD from those with natural progressive disease.

CONCLUSIONS AND RELEVANCE

Definitions of HPD appear to be diverse, with the incidence of HPD varying from 5.9% to 43.1% across studies examined in this meta-analysis. Varying incidence and definitions of HPD indicate the need for establishing its uniform and clinically relevant criteria based on currently available evidence.

Evaluation of equivocal small cystic pancreatic lesions with spectral-detector computed tomography

BACKGROUND

Evaluation of small cystic lesions of the pancreas remains a challenging task, as due to their size appearance can be rather hypodense than clearly fluid-filled.

PURPOSE

To evaluate whether additional information provided by novel dual-layer spectral-detector computed tomography (SDCT) imaging can improve assessment of these lesions.

MATERIAL AND METHODS

For this retrospective study, we reviewed reports of 1192 contrast-enhanced portal-venous phase SDCT scans of the abdomen conducted between May 2017 and January 2019. On basis of the radiological report 25 small (≤1.5 cm) cystic pancreatic lesions in 22 patients were identified, in which additional short-term follow-up imaging was recommended to confirm/clarify cystic nature. Conventional images (CI) and spectral images (SI) including virtual-monoenergetic images at 40 keV (VMI), iodine-density and iodine-overlay images were reconstructed. Two readers indicated lesion conspicuity and confidence for presence of cystic nature on three-point scales. First, solely CI were evaluated, while in a second reading after a four-week interval, the combination of CI and corresponding SI were reviewed. Quantitatively, ROI-based mean attenuation was measured in CI and VMI.

RESULTS

In the subjective reading, SI significantly improved lesion conspicuity (CI 2 [1-2], SI 3 [2-3], P < 0.001) and confidence regarding presence of cystic nature (CI 2 [1-2], SI 3 [3-3], P < 0.001). Inter-observer agreement depicted by intraclass correlation coefficient improved considerably from 0.51 with only CI to 0.85 when the combination with SI was used. Further, VMI displayed significantly higher signal-to-noise (CI 1.2 ± 0.8, VMI 3.2 ± 1.8, P < 0.001) and contrast-to-noise ratios (CI 2.6 ± 0.8, VMI 4.7 ± 1.9).

CONCLUSION

Compared to CI alone, combination with SI significantly improves visualization and confidence in evaluation of small equivocal cystic pancreatic lesions.

Trends in imaging utilization for small cell lung cancer: a decision tree analysis of the NCCN guidelines

PURPOSE

To investigate the differences in small cell lung cancer (SCLC) diagnostic imaging utilization relative to National Comprehensive Cancer Network (NCCN) guidelines.

METHODS

We retrospectively reviewed SCLC records at our institution between January 1, 2003 and August 1, 2019 (n = 529). Patients were grouped by extensive-stage versus limited-stage and diagnosis date. Clinical, CT, MRI, and nuclear imaging data was collected. Imaging utilization was compared using Student's t-test or Kruskal-Wallis-test/Wilcoxon-Rank-Sums test. Survival was compared using Log-rank-test and Kaplan-Meier-curves.

RESULTS

SCLC patients had a median survival of 290 days. Extensive-stage patients with SCLC demonstrated an increase in emergency imaging utilization when diagnosed in 2011-2019 compared to 2003-2010 (CT abdomen/pelvis p < 0.001, CTA chest for pulmonary embolism p < 0.01, CT head p < 0.003). Limited-stage patients with SCLC demonstrated an increase in inpatient imaging utilization (CT abdomen/pelvis p < 0.04) and decreased total/outpatient imaging utilization (CT chest-abdomen-pelvis p < 0.05, CT head p < 0.003) when diagnosed in 2011-2019 compared to 2003-2010. All patients with SCLC had decreased average number of bone-scan studies when diagnosed in 2011-2019 compared to 2003-2010 (Extensive-stage p < 0.006, Limited-stage p < 0.0006).

CONCLUSION

Imaging utilization trends in the management of patients with SCLC at our institution differed between 2003 and 2010 and 2011-2019 reflecting the changes in the NCCN guidelines.

A novel imaging based Nomogram for predicting post-surgical biochemical recurrence and adverse pathology of prostate cancer from pre-operative bi-parametric MRI

Background

We developed and validated an integrated radiomic-clinicopathologic nomogram (RadClip) for post-surgical biochemical recurrence free survival (bRFS) and adverse pathology (AP) prediction in men with prostate cancer (PCa). RadClip was further compared against extant prognostics tools like CAPRA and Decipher.

Methods

A retrospective study of 198 patients with PCa from four institutions who underwent pre-operative 3 Tesla MRI followed by radical prostatectomy, between 2009 and 2017 with a median 35-month follow-up was performed. Radiomic features were extracted from prostate cancer regions on bi-parametric magnetic resonance imaging (bpMRI). Cox Proportional-Hazards (CPH) model warped with minimum redundancy maximum relevance (MRMR) feature selection was employed to select bpMRI radiomic features for bRFS prediction in the training set (D₁, N = 71). In addition, a bpMRI radiomic risk score (RadS) and associated nomogram, RadClip, were constructed in D₁ and then compared against the Decipher, pre-operative (CAPRA), and post-operative (CAPRA-S) nomograms for bRFS and AP prediction in the testing set (D₂, N = 127).

Findings

“RadClip yielded a higher C-index (0.77, 95% CI 0.65-0.88) compared to CAPRA (0.68, 95% CI 0.57-0.8) and Decipher (0.51, 95% CI 0.33-0.69) and was found to be comparable to CAPRA-S (0.75, 95% CI 0.65-0.85). RadClip resulted in a higher AUC (0.71, 95% CI 0.62-0.81) for predicting AP compared to Decipher (0.66, 95% CI 0.56-0.77) and CAPRA (0.69, 95% CI 0.59-0.79).”

Interpretation

RadClip was more prognostic of bRFS and AP compared to Decipher and CAPRA. It could help pre-operatively identify PCa patients at low risk of biochemical recurrence and AP and who therefore might defer additional therapy.

Funding

The National Institutes of Health, the U.S. Department of Veterans Affairs, and the Department of Defense.

Extraprostatic extension in prostate cancer: primer for radiologists

The presence of extraprostatic extension (EPE) on multiparametric MRI (mpMRI) is an important factor in determining the management of prostate cancer. EPE is an established risk factor for biochemical recurrence of prostate cancer after radical prostatectomy (RP) and patients with EPE may be considered for wider resection margins, non-nerve-sparing surgery, adjuvant radiation therapy (RT), or androgen deprivation therapy (ADT). Several statistical nomograms and scoring systems have been developed to predict pathological stage at time of RP but with varying accuracies. Using the current PI-RADS v2 mpMRI staging guidelines results in high specificity but lacks in sensitivity. These findings reveal the need for more standardization and further refinement of existing MRI protocols and prostate cancer prediction tools. Current studies have looked into indirect additional imaging criteria such as index tumor volume, length of capsular contact, and apparent diffusion coefficient. Measuring for these features can improve the robustness of mpMRI in staging prostate cancer, as they have been shown to be independent predictors of EPE. MRI/ultrasound fusion-guided targeted biopsy can detect EPE not found on standard biopsy. Collectively, these measurements and imaging techniques can augment the detection of EPE and subsequent risk stratification.

Imaging of non-epithelial neoplasms of the prostate

The purpose of this article is to review the spectrum of rare non-epithelial tumors of the prostate. This focused article will help the readers to understand the imaging findings of such rare entities attributed to their clinicopathological features. Radiologists must be familiar with the spectrum of non-epithelial tumors of the prostate, which helps to suggest alternate diagnosis other than adenocarcinoma, when imaging features are atypical. This is important because these tumors have different management approaches and prognoses when compared to adenocarcinoma of the prostate.

Imaging and clinical manifestations of immune checkpoint inhibitor-related colitis in cancer patients treated with monotherapy or combination therapy

PURPOSE

To determine the frequency, imaging, and clinical manifestations of immune checkpoint inhibitor (ICI)-related colitis in cancer patients on monotherapy or combination therapy.

METHODS

The electronic medical records of 1044 cancer patients who received ICIs were retrospectively reviewed to identify 48 patients who had a clinical diagnosis of immune-related colitis. Imaging studies were reviewed to identify patients with imaging manifestations of colitis. Demographic data, type of ICIs, symptoms, presence of other immune-related adverse events (irAEs), and management were recorded.

RESULTS

There was imaging evidence of immune-related colitis in 34 patients (24 men; median age: 63.5 years). The median time to onset of colitis was 75 days (IQR 25-75, 49.5-216 days) in patients receiving monotherapy (group 1) and 78 days (IQR 25-75, 44.3-99.5 days) in patients undergoing combination therapy (group 2) following start of ICI. Symptoms included diarrhea (91.1% [31 of 34]), nausea/vomiting (52.9% [18 of 34]), and abdominal pain (52.9% [18 of 34]). The most common imaging findings were bowel wall thickening (97% [33 of 34]) and fluid-filled colon (82.3% [28 of 34]). Colitis was diffuse in 21 of 34 (61.8%) patients. Imaging manifestations did not differ between the two groups (p > 0.05). Steroids and antibiotics were used to treat colitis in 29 of 34 (85.2%) and 13 of 34 (38.2%) patients, respectively. No patients in group 1 experienced concurrent irAEs, but 5 of 18 (27.8%) of patients in group 2 had other irAEs (p = 0.046).

CONCLUSION

Immune-related colitis occurred in 3.3% of patients receiving ICIs with bowel wall thickening, fluid-filled colon and pancolitis being the most common imaging manifestations. Imaging manifestations did not differ between patients receiving monotherapy or combination therapy. However, concurrent irAEs were significantly observed in patients undergoing combination therapy.

Imaging features of gastrointestinal toxicity in non-small cell lung cancer patients treated with erlotinib: A single institute 13-year experience

OBJECTIVES

To investigate the imaging features of erlotinib-associated gastrointestinal toxicity (GT) in patients with non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

The electronic medical records of 157 patients with NSCLC who received erlotinib between 2005 and 2018 were retrospectively reviewed to identify patients with GT. Clinical and radiologic evidence of erlotinib-associated GT was evaluated. Imaging findings were cross-referenced with clinical presentation, management, and outcomes.

RESULTS

24 (15%) patients (16 women; median age, 68 years) with radiologic evidence of GT were identified. The median time to detection of GT on imaging was 4.5 months (range: 0-58 months). 3/24 (12.5%) patients had no clinical symptoms, but GT was radiologically identified. Erlotinib-associated GT manifested in the large bowel in either a diffuse (42%) or segmental (58%) pattern. The most common imaging finding was fluid-filled bowel (23/24, 96%).

CONCLUSION

Erlotinib-associated GT was identified in 15% patients with NSCLC. Fluid-filled colon and segmental involvement were the most common imaging manifestations.

Quantifying the decrease in emergency department imaging utilization during the COVID-19 pandemic at a multicenter healthcare system in Ohio

Purpose

To illustrate the change in emergency department (ED) imaging utilization at a multicenter health system in the state of Ohio during the COVID-19 pandemic.

Methods

A retrospective observational study was conducted assessing ED imaging volumes between March 1, 2020, and May 11, 2020, during the COVID-19 crisis. A rolling 7-day total value was used for volume tracking and comparison. Total imaging utilization in the ED was compared with new COVID-19 cases in our region. Utilization was first categorized by modality and then by plain films and computed tomography (CT) scans grouped by body part. CT imaging of the chest was specifically investigated by assessing both CT chest only exams and CT chest, abdomen, and pelvis (C/A/P) exams. Ultimately, matching pair-wise statistical analysis of exam volumes was performed to assess significance of volume change.

Results

Our multicenter health system experienced a 46% drop in imaging utilization (p < 0.0001) during the pandemic. Matching pair-wise analysis showed a statistically significant volume decrease by each modality and body part. The exceptions were non-contrast chest CT, which increased (p = 0.0053), and non-trauma C/A/P CT, which did not show a statistically significant volume change (p = 0.0633).

Conclusion

ED imaging utilization trends revealed through actual health system data will help inform evidence-based decisions for more accurate volume predictions and therefore institutional preparedness for current and future pandemics.

COVID-19 Pandemic Impact on Decreased Imaging Utilization: A Single Institutional Experience

RATIONALE AND OBJECTIVES

Predictive models and anecdotal articles suggest radiology practices were losing 50%-70% of their normal imaging volume during the COVID-19 pandemic. Using actual institutional data, we investigated the change in imaging utilization and revenue during this public health crisis.

MATERIALS AND METHODS

Imaging performed within the 8-week span between March 8 and April 30, 2020 was categorized into the COVID-19 healthcare crisis timeframe. The first week of this date range and the 10 weeks prior were used to derive the normal practice expected volume. A rolling 7-day total value was used for volume tracking and comparison. Total imaging utilization was derived and organized by patient setting (outpatient, inpatient, emergency) and imaging modality (X-ray, CT, Mammography, MRI, Nuclear Medicine/PET, US). The three highest volume hospitals were analyzed. Revenue information was collected from the hospital billing system.

RESULTS

System-wide imaging volume decreased by 55% between April 7 and 13, 2020. Outpatient exams decreased by 68% relative to normal practice. Emergency exams decreased by 48% and inpatient exams declined by 31%. Mammograms and nuclear medicine scans were the most affected modalities, decreasing by 93% and 61%, respectively. The main campus hospital experienced less relative imaging volume loss compared to the other smaller and outpatient-driven hospitals. At its lowest point, the technical component revenue from main campus imaging services demonstrated a 49% negative variance from normal practice.

CONCLUSION

The trends and magnitude of the actual imaging utilization data presented will help inform evidence-based decisions for more accurate volume predictions, policy changes, and institutional preparedness for current and future pandemics.

Utilization of imaging in pancreatic adenocarcinoma patients status post Whipple procedure

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Background: Pancreatic adenocarcinoma (PAC) remains the third leading cause of cancer death in the Western world. The 5-year survival of patients with PAC remains at 4%. Proper utilization of imaging to detect recurrence is necessary in patients who have undergone a Whipple procedure. Currently, Carbohydrate (CA) 19-9 is used for screening and is the only biomarker approved by the Food and Drug Administration (FDA). Sensitivity and specificity range from 79-81% and 82-90%. We intend to evaluate our single institute experience of imaging utilization, CA 19-9, and surgical specimen histopathologic features in the surveillance of PAC patients status post Whipple. Methods: Retrospective analysis of patients with a diagnosis of PAC who underwent imaging status post Whipple from 2008 - 2018 was completed. Cross-sectional imaging and clinical data was obtained from the electronic health record. Results: A total of 197 PAC patients status post Whipple were identified with mean age at diagnosis at 64.4 years and male to female ratio of 1.3. 85 patients were found to have died during treatment. The median survival for these patients was 68 years. Of the patients who died status post Whipple, postoperative CA 19-9 levels within 6 months of the procedure were elevated (p = 0.01). Patients who were found to have stage II to IV PAC at diagnosis were found to have a high CA 19-9 level within 6 months post-Whipple when compared to stage I patients (p < 0.05). Patients who were found to have less than 5 surveillance CTs status post Whipple were found to have higher CA 19-9 levels within 6 months status post Whipple (p < 0.01). There was no difference in number of CT scans between stages. Of those patients who died with stage I or II PAC at diagnosis, a large number were found to have less than 5 surveillance CT studies completed status post Whipple (p < 0.05). Furthermore, a higher cancer stage at diagnosis correlated with worse pathologic differentiation of the cancer (p < 0.001). Conclusions: Post Whipple CA 19-9 correlated with stage, recurrence, number of scans, and survival.

Update on Hodgkin lymphoma from a radiologist's perspective

Recent advances in the management of Hodgkin lymphoma, due to new staging and response assessment systems as well as new therapies, have redefined the role of imaging for this disease. The purpose of this article is to provide radiologists with an update on the current role of imaging in Hodgkin lymphoma from diagnosis to assessment of treatment response, in view of the new staging and response assessment system and current treatment strategies.

A pictorial review of non-traumatic adrenergic crisis

Non-traumatic adrenal crisis is a rare but critical diagnosis to make in emergency settings due to grave consequences. Various pathologies can present as acute crisis, such as spectrum of endocrine imbalance, ranging from catecholamine excess in pheochromocytomas to acute adrenal insufficiency related to glandular dysfunction. Critical manifestations may be due to structural causes related to adrenal hemorrhage, especially when they are bilateral. Oncological complications such as vascular invasion, tumoral bleed, rupture, and hormonal dysfunction can occur. Due to non-specific clinical presentation, these conditions may come as a surprise on imaging performed for other reasons. Recognition of these imaging findings is critical for appropriate patient management. Although there are few articles discussing non-traumatic emergencies in literature, this review is inclusive of all possible etiologies, thus provides a holistic approach and insight into each situation. Specific imaging approach is needed to tailor the diagnosis. This article will also discuss about the advanced imaging techniques that will complement diagnosis.

Overview of imaging findings associated with systemic therapies in advanced epithelial ovarian cancer

PURPOSE

To provide an overview for radiologists of the systemic agents used in the treatment of advanced epithelial ovarian cancer (EOC) and their associated toxicities.

RESULTS

EOC is a common gynecological malignancy, with the majority of patients presenting with advanced stage disease at the time of diagnosis. Although primary cytoreductive surgery and chemotherapy are the principal treatments for EOC, recurrence rates of disease remain high. As several molecular targeted therapies have been developed in the last decade, various novel agents have shown efficacy in the treatment of advanced EOC. Advanced EOC will be discussed by outlining the relevant radiological features of toxicities.

CONCLUSION

Knowledge of the systemic therapies utilized in the treatment of advanced EOC and their associated radiological features is critical in diagnostic image interpretation.

Tumor Response Criteria in Oncoimaging: RECIST Criteria and beyond—Part 1

The rapid recent advances in oncology have made the dream of precision oncology a reality, with targeted therapy available for various tumors depending on the molecular genotype. This has led to the corresponding development of personalized radiology as well, with various tumor response criteria used to characterize disease response/progression depending on chemotherapy used. In these two review articles, we review the various tumor response criteria widely applied in both research and clinical settings. These include the classic size-based criteria such as RECIST (Response Evaluation Criteria in Solid Tumors) 1.1 and the WHO (World Health Organization) criteria, as also various other criteria such as Choi and modified Choi criteria for tumors treated by targeted therapy, EASL and modified RECIST (mRECIST) criteria for hepatocellular carcinomas, and immune-related response criteria (irRC) and immune RECIST (iRECIST) for patients on immunotherapy. Other clinically important criteria such as PERCIST (PET Response Criteria In Solid Tumors) for positron emission tomography–computed tomography (PET-CT) and the MD Anderson criteria for evaluating bone metastases are also highlighted.

Tumor Response Criteria in Oncoimaging: RECIST Criteria and beyond—Part 2

The rapid recent advances in oncology have made the dream of precision oncology a reality, with targeted therapy available for various tumors depending on the molecular genotype. This has led to the corresponding development of personalized radiology as well, with various tumor response criteria used to characterize disease response/progression depending on chemotherapy used. In these two review articles, we review the various tumor response criteria widely applied in both research and clinical settings. These include the classic size-based criteria such as RECIST (Response Evaluation Criteria In Solid Tumors) 1.1 and the WHO (World Health Organization) criteria, as also various other criteria such as Choi and modified Choi criteria for tumors treated by targeted therapy, EASL (European Association for the Study of the Liver) and modified RECIST (mRECIST) criteria for hepatocellular carcinomas, immune-related response criteria (irRC) and immune RECIST (iRECIST) for patients on immunotherapy. Other clinically important criteria such as PERCIST (PET Response Criteria In Solid Tumors) for positron emission tomography–computed tomography (PET-CT), and the MD Anderson criteria for evaluating bone metastases are also highlighted.

Cancer genome landscape: a radiologist's guide to cancer genome medicine with imaging correlates

The introduction of high throughput sequence analysis in the past decade and the decrease in sequencing costs has made available an enormous amount of genomic data. These data have shaped the landscape of cancer genome, which encompasses mutations determining tumorigenesis, the signaling pathways involved in cancer growth, the tumor heterogeneity, and its role in development of metastases. Tumors develop acquiring a series of driver mutations over time. Of the many mutated genes present in cancer, only few specific mutations are responsible for invasiveness and metastatic potential, which, in many cases, have characteristic imaging appearance. Ten signaling pathways, each with targetable components, have been identified as responsible for cancer growth. Blockage of any of these pathways form the basis for molecular targeted therapies, which are associated with specific pattern of response and toxicities. Tumor heterogeneity, responsible for the different mutation pattern of metastases and primary tumor, has been classified in intratumoral, intermetastatic, intrametastatic, and interpatient heterogeneity, each with specific imaging correlates. The purpose of this article is to introduce the key components of the landscapes of cancer genome and their imaging counterparts, describing the types of mutations associated with tumorigenesis, the pathways of cancer growth, the genetic heterogeneity involved in metastatic disease, as well as the current challenges and opportunities for cancer genomics research.

Imaging surveillance of gastrointestinal stromal tumour: current recommendation by National Comprehensive Cancer Network and European Society of Medical Oncology-European Reference Network for rare adult solid cancers

Imaging plays an active role in the surveillance of gastrointestinal stromal tumours (GISTs). Risk stratification schemes, based on size, mitotic count, and anatomical site of origin of the GIST, help in planning preoperative and postoperative imaging strategies especially in determining the frequency and duration of surveillance; however, there is no clear consensus on the optimal imaging strategies in patients with GISTs who are completely cured by surgery and patients who are at risk of recurrence. In addition, current surveillance protocols depend on the resectability of the primary tumour and presence of metastatic disease. The objective of this article is to provide a comprehensive review of the role of the different imaging methods for surveillance of GISTs, focusing on the guidelines recommended by National Comprehensive Cancer Network and European Society of Medical Oncology - European Network for Rare adult solid Cancers, and to propose practical guidelines for surveillance of GISTs for various risk categories.

An update on Burkitt lymphoma: a review of pathogenesis and multimodality imaging assessment of disease presentation, treatment response, and recurrence

Burkitt lymphoma (BL) is a highly aggressive, rapidly growing B cell non-Hodgkin lymphoma, which manifests in several subtypes including sporadic, endemic, and immunodeficiency-associated forms. Pathologically, BL is classically characterized by translocations of chromosomes 8 and 14 resulting in upregulation of the c-myc protein transcription factor with upregulation of cell proliferation. BL affects nearly every organ system, most commonly the abdomen and pelvis in the sporadic form. Imaging using a multimodality approach plays a crucial role in the management of BL from diagnosis, staging, and evaluation of treatment response to therapy-related complications with ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography playing roles. In this article, we review the pathobiology and classification of BL, illustrate a multimodality imaging approach in evaluating common and uncommon sites of involvement within the trunk and head and neck, and review common therapies and treatment-related complications.

Frequency and imaging features of abdominal immune-related adverse events in metastatic lung cancer patients treated with PD-1 inhibitor

PURPOSE

To investigate the frequency and imaging features of radiographically evident abdominal immune-related adverse events (irAEs) in patients with metastatic non-small-cell lung cancer (NSCLC) treated with PD-1 inhibitors.

METHODS

This retrospective study included 137 patients with metastatic NSCLC treated with PD-1 inhibitor nivolumab monotherapy (75 women; median age: 65 years), who had a baseline CT and at least one follow-up abdomen CT during therapy. Baseline and all follow-up abdominal CTs performed for monitoring of nivolumab therapy were reviewed to identify the organ-specific abdominal irAEs including colitis/enteritis, hepatitis, biliary toxicity, pancreatitis, nephritis, sarcoid-like reaction, and pancreatic and adrenal atrophy. Their frequency and imaging features were described.

RESULTS

Eighteen (13%) patients had radiologically identified abdominal irAEs (median 2.1 months after starting nivolumab; interquartile range 1.17-5.83 months); 16 patients developed enteritis/colitis (12 pancolitis, two segmental colitis, one enterocolitis, one enteritis), two hepatitis, one adrenalitis. One patient with hepatitis also developed colitis/enteritis. Radiographic abdominal irAE occurred after nivolumab therapy was discontinued in six patients before any subsequent therapy was started. IrAEs prompted nivolumab interruption and treatment with steroids in four patients (three colitis/enteritis, one hepatitis). Most common CT features of colitis/enteritis included mesenteric hyperemia (n = 15), bowel wall thickening (n = 13), mucosal hyperenhancement (n = 10), and fluid-filled colon (n = 9).

CONCLUSION

Abdominal irAEs were detected on CT in 13% of NSCLC patients treated with nivolumab, and colitis, in the pancolitis form, was the most common irAE. Given the expanding role of immunotherapy, radiologists should be aware of the frequency and imaging manifestations of abdominal irAEs and the impact on patient management.

Lobular breast cancer: patterns of intraabdominal metastatic spread on imaging and prognostic significance

OBJECTIVE

To retrospectively review the frequency, patterns and intra-abdominal sites of metastatic invasive lobular breast cancer, and to correlate the findings with overall survival.

MATERIALS AND METHODS

From a pathology database search revealing 327 patients with metastatic lobular breast cancer at our institution from January 2004 through August 2014, imaging was available in 116 patients (age range, 31-87 years, mean age, 55). Simple descriptive statistics were performed to record and tabulate the abdominal metastatic spread. Prognostic significance of abdominal metastases and individual abdominal metastatic sites was studied using the Log-rank test and construction of Kaplan-Meier curves.

RESULTS

The most frequent sites of intra-abdominal metastatic invasive lobular breast cancer were peritoneum (55 patients, 47%), followed by liver (37 patients, 32%), bowel (34 patients, 29%), ovary (33 patients, 28%), retroperitoneum (16 patients, 14%), ureter (16 patients, 14%), and lymph nodes (15 patients, 13%). Bowel obstruction was noted in 15 patients (13%) and hydronephrosis in 25 patients (22%). The median abdominal metastasis-free survival was 76 months (interquartile range: 17-191). The overall survival (OS) was 86 months (interquartile range: 49-188). Patients with abdominal metastases had shorter OS. Patients with hepatic metastases had shorter overall survival than those patients without hepatic metastases (p = 0.02, Log-Rank test).

CONCLUSION

Invasive lobular breast cancer has a predilection for metastasizing to both typical (liver) and atypical intra-abdominal sites (peritoneum, GI tract, and adnexa). Presence of intra-abdominal disease and hepatic metastases in patients with ILC negatively affects overall survival.