Publications

The objective of this review is to discuss the clinical and histopathologic features, MRI characteristics, and management options of retroperitoneal cystic masses. Radiologists should be familiar with the MR imaging characteristics of retroperitoneal cystic masses to allow for a refined differential diagnosis, assist with lesion management, and prevent unnecessary invasive procedures.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive gastrointestinal malignancy with a poor 5-year survival rate. Accurate staging of PDAC is an important initial step in the development of a stage-specific treatment plan. Different staging systems/consensus statements convened by different societies and academic practices are currently used. The most recent version of the American Joint Committee on Cancer (AJCC) tumor/node/metastases (TNM) staging system for PDAC has shifted its focus from guiding management to assessing prognosis. In order to preoperatively define the resectability of PDAC and to guide management, additional classification systems have been developed. The National Comprehensive Cancer Network (NCCN) guidelines, one of the most commonly used systems, provide recommendations on the management and the determination of resectability for PDAC. The NCCN divides PDAC into three categories of resectability based on tumor-vessel relationship: 'resectable,' 'borderline resectable,' and 'unresectable'. Among these, the borderline disease category is of special interest given its evolution over time and the resulting variations in the definition and the associated recommendations for management between different societies. It is important to be familiar with the evolving criteria, and treatment and follow-up recommendations for PDAC. In this article, the most current AJCC staging (8th edition), NCCN guidelines (version 2.2019-April 9, 2019), and challenges and controversies in borderline resectable PDAC are reviewed.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive gastrointestinal malignancy with a poor 5-year survival rate. Its high mortality rate is attributed to its aggressive biology and frequently late presentation. While surgical resection remains the only potentially curative treatment, only 10-20% of patients will present with surgically resectable disease. Over the past several years, development of vascular bypass graft techniques and introduction of neoadjuvant treatment regimens have increased the number of patients who can undergo resection with a curative intent. While the role of conventional imaging in the detection, characterization, and staging of patients with PDAC is well established, its role in monitoring treatment response, particularly following neoadjuvant therapy remains challenging because of the complex anatomic and histological nature of PDAC. Novel morphologic and functional imaging techniques (such as DECT, DW-MRI, and PET/MRI) are being investigated to improve the diagnostic accuracy and the ability to measure response to therapy. There is also a growing interest to detect PDAC and its precursor lesions at an early stage in asymptomatic patients to increase the likelihood of achieving cure. This has led to the development of pancreatic cancer screening programs. This article will review recent updates in imaging techniques and the current status of screening and surveillance of individuals at a high risk of developing PDAC.

BACKGROUND: There are increased options to deliver thrombolytic treatment for acute, high-risk pulmonary embolism (PE). The goals of this study were to examine practice patterns of systemic thrombolysis and catheter-directed thrombolysis (CDT) and to compare outcomes following CDT with ultrasound facilitation (CDT-ultrasound) and CDT alone.

METHODS: The study analyzed adults aged > 18 years with hospitalizations associated with acute PE and thrombolysis in the 2016 Nationwide Readmissions Database. The study identified characteristics associated with the use of systemic thrombolysis and CDT. Comparisons of CDT-ultrasound vs CDT alone were then made by evaluating in-hospital events and readmissions. The primary outcomes were in-hospital mortality and 30-day readmission rates.

RESULTS: Among 5,436 hospitalizations, systemic thrombolysis was used more often (n = 3,376; 62.1%) than CDT (n = 2,060; 37.9%). Compared with CDT, systemic thrombolysis was used more frequently in patients with higher rates of vasopressor use (4.3% vs 1.0%), shock (15.8% vs. 6.9%), cardiac arrest (12.7% vs 3.4%), and mechanical ventilation (19.0% vs 5.9%). Among patients who underwent CDT, 417 (20.2%) received CDT-ultrasound, and 1,643 (79.8%) received CDT alone. Rates of bleeding events, vasopressor use, and mechanical ventilation were similar between therapeutic strategies. Following adjustment, in-hospital mortality (OR, 1.19; 95% CI, 0.63-2.26; P = .59) and 30-day readmission rates (OR, 0.75; 95% CI, 0.47-1.22; P = .25) were not significantly different between CDT-ultrasound and CDT alone.

CONCLUSIONS: Systemic thrombolysis is used more often than CDT in patients with acute PE, in particular among those with a greater prevalence of high-risk features. Among patients treated with CDT, there were no differences in events between CDT-ultrasound and CDT alone.

PURPOSE: To assess the impact of pre-procedural evaluation of patients with symptomatic uterine fibroids and adenomyosis in interventional radiology (IR) clinic.

METHOD: In this IRB-approved, HIPAA-compliant retrospective study, consecutive patients evaluated in the IR clinic in a tertiary academic hospital between 1/1/2015 and 9/30/2018 by a single board-certified interventional radiologist were included. Medical records were reviewed to obtain medical history, imaging and endometrial biopsies results. Impact of IR clinic assessment of clinical, imaging, and pathological findings on patient's clinical course was assessed. Descriptive statistics were used.

RESULTS: 208 consecutive patients were evaluated in clinic for uterine fibroids 176/208 (85%), adenomyosis 8/208 (4%) or both 24/208 (11%) with age of 44.4 ± 5.8 years and BMI of 30.1 ± 8.6 kg/m2. Leading presenting symptom was menorrhagia in 172/208 (80%) patients, pelvic pain in 91/208 (44%), and urinary symptoms in 88/208 (42%) patients. 159/208 (76%) patients underwent UAE, 12/208 (6%) patients underwent surgery, and 37/208 (18%) patients chose conservative management. 189/208 (91%) patients had pelvic MRI that altered management course in 7/189 (4%) patients due to intracavitary fibroids in two patients, endometrial polyps in two patients, non-enhancing fibroids in two patients, and adnexal mass in one patient. 166/208 (80%) underwent endometrial biopsy that altered management course in one patient (0.6%) due to endometrial intraepithelial neoplasia.

CONCLUSION: Endometrial biopsy and pelvic MRI are helpful to detect cases of non-enhancing fibroids, intracavitary fibroids, and ovarian and endometrial malignancies and thus altered management of five percent of patients with symptomatic fibroids and adenomyosis.

BACKGROUND: More than 100 million adults in the US suffer from prediabetes or type-2 diabetes. Noninvasive imaging of pancreas endocrine function might provide a surrogate marker of β-cell functional integrity loss linked to this disease.

PURPOSE: To noninvasively assess pancreatic blood-flow modulation following a glucose challenge using arterial spin labeling (ASL) MRI.

STUDY TYPE: Prospective.

SUBJECTS: Fourteen adults (30 ± 7 years old, 3M/11F, body mass index [BMI] = 24 ± 3 kg.m-2 ).

FIELD STRENGTH/SEQUENCE: 3T MRI / background-suppressed pseudocontinuous PCASL preparation with single-shot fast-spin-echo (FSE) readout before and after an oral glucose challenge using either fruit juice (n = 7) or over-the-counter glucose gel (n = 7).

ASSESSMENT: Subjects were fasting prior to initiation of oral stimulation, then dynamic perfusion measurements were performed every 2 minutes for 30 minutes. We quantified absolute blood flow at each timepoint.

STATISTICAL TESTS: Repeated-measures analysis of variance (ANOVA) followed by paired t-tests to assess for a significant effect of glucose challenge on measured perfusion.

RESULTS: Measured basal blood flow was 187 ± 53 mL/100g/min. A significant blood flow increase of +38 ± 26% was observed 10 minutes poststimulation (P < 0.05) and continuing until the end of the experiment. The gel stimulation provided the most consistent results, with an early rise followed by an additional later increase consistent with the known pancreatic insulin response to elevated blood glucose. Across-subject variations in blood flow increase were partially attributable to basal flow, with a negative correlation of r = -0.84 between basal and maximal relative flow increase in the gel group.

DATA CONCLUSION: ASL can be used to measure pancreatic flow in response to a glucose challenge, which could be linked to insulin release and secretion. This paradigm might be useful to characterize disorders of glucose regulation.

LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:854-860.

BACKGROUND: To maintain cerebral blood flow (CBF), cerebral blood vessels dilate and contract in response to blood supply through cerebrovascular reactivity (CR).

PURPOSE: Cardiovascular (CV) disease is associated with increased stroke risk, but which risk factors specifically impact CR is unknown.

STUDY TYPE: Prospective longitudinal.

SUBJECTS: Fifty-three subjects undergoing carotid endarterectomy or stenting.

FIELD STRENGTH/SEQUENCE: 3T, 3D pseudo-continuous arterial spin labeling (PCASL) ASL, and T1 3D fast spoiled gradient echo (FSPGR).

ASSESSMENT: We evaluated group differences in CBF changes for multiple cardiovascular risk factors in patients undergoing carotid revascularization surgery.

STATISTICAL TESTS: PRE (baseline), POST (48-hour postop), and 6MO (6 months postop) whole-brain CBF measurements, as 129 CBF maps from 53 subjects were modeled as within-subject analysis of variance (ANOVA). To identify CV risk factors associated with CBF change, the CBF change from PRE to POST, POST to 6MO, and PRE to 6MO were modeled as multiple linear regression with each CV risk factor as an independent variable. Statistical models were performed controlling for age on a voxel-by-voxel basis using SPM8. Significant clusters were reported if familywise error (FWE)-corrected cluster-level was P < 0.05, while the voxel-level significance threshold was set for P < 0.001.

RESULTS: The entire group showed significant (cluster-level P < 0.001) CBF increase from PRE to POST, decrease from POST to 6MO, and no significant difference (all voxels with P > 0.001) from PRE to 6MO. Of multiple CV risk factors evaluated, only elevated systolic blood pressure (SBP, P = 0.001), chronic renal insufficiency (CRI, P = 0.026), and history of prior stroke (CVA, P < 0.001) predicted lower increases in CBF PRE to POST. Over POST to 6MO, obesity predicted lower (P > 0.001) and cholesterol greater CBF decrease (P > 0.001).

DATA CONCLUSION: The CV risk factors of higher SBP, CRI, CVA, BMI, and cholesterol may indicate altered CR, and may warrant different stroke risk mitigation and special consideration for CBF change evaluation.

LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2020;51:734-747.

OBJECTIVE: There is insufficient large-scale evidence for screening mammography in women <40 years at elevated risk. This study compares risk-based screening of women aged 30 to 39 with risk factors versus women aged 40 to 49 without risk factors in the National Mammography Database (NMD).

METHODS: This retrospective, HIPAA-compliant, institutional review board-exempt study analyzed data from 150 NMD mammography facilities in 31 states. Patients were stratified by 5-year age intervals, availability of prior mammograms, and specific risk factors for breast cancer: family history of breast cancer, personal history of breast cancer, and dense breasts. Four screening performance metrics were calculated for each age and risk group: recall rate (RR), cancer detection rate (CDR), and positive predictive values for biopsy recommended (PPV2) and biopsy performed (PPV3).

RESULTS: Data from 5,986,131 screening mammograms performed between January 2008 and December 2015 in 2,647,315 women were evaluated. Overall, mean CDR was 3.69 of 1,000 (95% confidence interval: 3.64-3.74), RR was 9.89% (9.87%-9.92%), PPV2 was 20.1% (19.9%-20.4%), and PPV3 was 28.2% (27.0%-28.5%). Women aged 30 to 34 and 35 to 39 had similar CDR, RR, and PPVs, with the presence of the three evaluated risk factors associated with significantly higher CDR. Moreover, compared with a population currently recommended for screening mammography in the United States (aged 40-49 at average risk), incidence screening (at least one prior screening examination) of women aged 30 to 39 with the three evaluated risk factors has similar cancer detection rates and recall rates.

DISCUSSION: Women with one or more of these three specific risk factors likely benefit from screening commencing at age 30 instead of age 40.

Pneumothorax is a potentially life-threatening condition that requires prompt recognition and often urgent intervention. In the ICU setting, large numbers of chest radiographs are performed and must be interpreted on a daily basis which may delay diagnosis of this entity. Development of artificial intelligence (AI) techniques to detect pneumothorax could help expedite detection as well as localize and potentially quantify pneumothorax. Open image analysis competitions are useful in advancing state-of-the art AI algorithms but generally require large expert annotated datasets. We have annotated and adjudicated a large dataset of chest radiographs to be made public with the goal of sparking innovation in this space. Because of the cumbersome and time-consuming nature of image labeling, we explored the value of using AI models to generate annotations for review. Utilization of this machine learning annotation (MLA) technique appeared to expedite our annotation process with relatively high sensitivity at the expense of specificity. Further research is required to confirm and better characterize the value of MLAs. Our adjudicated dataset is now available for public consumption in the form of a challenge.