Publications

BACKGROUND: Noninvasive quantitative measurement of fibrosis in chronic kidney disease (CKD) would be desirable diagnostically and therapeutically but standard radiologic imaging is too variable for clinical usage. By applying a vibratory force, tissue shear wave stiffness can be measured by magnetic resonance elastography (MRE) that may correlate with progression of kidney fibrosis. Since decreased kidney perfusion decreases tissue turgor and stiffness, we combined newly available three-dimensional MRE shear stiffness measurements with MR arterial spin labeling (ASL) kidney blood flow rates to evaluate fibrosis in diabetic nephropathy.

METHODS: Thirty individuals with diabetes and Stage 0-5 CKD and 13 control individuals without CKD underwent noncontrast MRE with concurrent ASL blood flow measurements.

RESULTS: MRE cortical shear stiffness at 90 Hz was decreased significantly below controls in all CKD stages of diabetic nephropathy. Likewise, ASL blood flow decreased progressively from 480 ± 136 mL/min/100 g of cortical tissue in controls to 302 ± 95, 229 ± 7 and 152 ± 32 mL/min/100 g in Stages 3, 4 and 5 CKD, respectively. A magnetic resonance imaging (MRI) surrogate for the measured glomerular filtration fraction [surrogate filtration fraction = estimated glomerular filtration rate (eGFR)/ASL] decreased progressively from 0.21 ± 0.07 in controls to 0.16 ± 0.04 in Stage 3 and 0.10 ± 0.02 in Stage 4-5 CKD.

CONCLUSIONS: In this pilot study, MRI with ASL blood flow rates can noninvasively measure decreasing kidney cortical tissue perfusion and, with eGFR, a decreasing surrogate filtration fraction in worsening diabetic nephropathy that appears to correlate with increasing fibrosis. Differing from the liver, MRE shear stiffness surprisingly decreases with worsening CKD, likely related to decreased tissue turgor from lower blood flow rates.

Deep invasive gastrointestinal endometriosis (DIGIE) is a frequent and severe presentation of endometriosis. Although most cases invade the rectosigmoid colon, DIGIE can involve any portion of the gastrointestinal tract from the stomach to the rectum, and is commonly multifocal and multicentric. Although histopathologic confirmation with surgery remains the gold standard for diagnosis, ultrasound (US) and magnetic resonance imaging (MRI) are the key non-invasive imaging modalities for initial assessment. US may be preferred as a screening study because of its easy availability and low-cost. Pelvic MRI and magnetic resonance enterography (MRE) provide substantial advantages for disease mapping in the pre-operative period, particularly in extensive bowel endometriosis. Although medical management of DIGIE with hormonal therapy can help control symptoms, disease course can be relentless and require surgical intervention. Surgical options depend on, the location; length; depth; circumference; multicentric or multifocal disease. With procedures including simple excision, fulguration of superficial lesions, shaving, disc excision, and segmental resection. A successful treatment outcome is largely dependent on good communication between the treating surgeon and the radiologist, who can provide vital information for effective surgical planning by reporting the key elements that we elaborate upon in this paper.

Despite widespread use of taxanes, mechanisms of action and resistance in vivo remain to be established, and there is no way of predicting who will respond to therapy. This study examined prostate cancer (PCa) xenografts and patient samples to identify in vivo mechanisms of taxane action and resistance. Docetaxel drug-target engagement was assessed by confocal anti-tubulin immunofluorescence to quantify microtubule bundling in interphase cells and aberrant mitoses. Tumor biopsies from metastatic PCa patients obtained 2 to 5 days after their first dose of docetaxel or cabazitaxel were processed to assess microtubule bundling, which correlated with clinical response. Microtubule bundling was evident in PCa xenografts 2 to 3 days after docetaxel treatment but was decreased or lost with acquired resistance. Biopsies after treatment with leuprolide plus docetaxel showed extensive microtubule bundling as did biopsies obtained 2 to 3 days after initiation of docetaxel or cabazitaxel in 2 patients with castration-resistant PCa with clinical responses. In contrast, microtubule bundling in biopsies 2 to 3 days after the first dose of docetaxel was markedly lower in 4 nonresponding patients. These findings indicate that taxanes target both mitotic and interphase cells in vivo and that resistance is through mechanisms that impair drug-target engagement. Moreover, the findings suggest that microtubule bundling after initial taxane treatment may be a predictive biomarker for clinical response.

BACKGROUND: There is an increasing interest in non-contrast-enhanced magnetic resonance imaging (MRI) for detecting and evaluating breast lesions. We present a methodology utilizing lesion core and periphery region of interest (ROI) features derived from directional diffusion-weighted imaging (DWI) data to evaluate performance in discriminating benign from malignant lesions in dense breasts.

METHODS: We accrued 55 dense-breast cases with 69 lesions (31 benign; 38 cancer) at a single institution in a prospective study; cases with ROIs exceeding 7.50 cm2 were excluded, resulting in analysis of 50 cases with 63 lesions (29 benign, 34 cancers). Spin-echo echo-planar imaging DWI was acquired at 1.5 T and 3 T. Data from three diffusion encoding gradient directions were exported and processed independently. Lesion ROIs were hand-drawn on DWI images by two radiologists. A region growing algorithm generated 3D lesion models on augmented apparent-diffusion coefficient (ADC) maps and defined lesion core and lesion periphery sub-ROIs. A lesion-core and a lesion-periphery feature were defined and combined into an overall classifier whose performance was compared to that of mean ADC using receiver operating characteristic (ROC) analysis. Inter-observer variability in ROI definition was measured using Dice Similarity Coefficient (DSC).

RESULTS: The region-growing algorithm for 3D lesion model generation improved inter-observer variability over hand drawn ROIs (DSC: 0.66 vs 0.56 (p < 0.001) with substantial agreement (DSC > 0.8) in 46% vs 13% of cases, respectively (p < 0.001)). The overall classifier improved discrimination over mean ADC, (ROC- area under the curve (AUC): 0.85 vs 0.75 and 0.83 vs 0.74 respectively for the two readers).

CONCLUSIONS: A classifier generated from directional DWI information using lesion core and lesion periphery information separately can improve lesion discrimination in dense breasts over mean ADC and should be considered for inclusion in computer-aided diagnosis algorithms. Our model-based ROIs could facilitate standardization of breast MRI computer-aided diagnostics (CADx).

Our goal was to determine the most important predictors and construct a nomogram for overall survival (OS) in oral cavity squamous cell cancer (OCSCC) treated with primary surgery followed by observation, adjuvant radiation or chemoradiation. Multivariable analysis was performed using Cox Proportional Hazard model of 9258 OCSCC patients from Surveillance, Epidemiology and End Results Program (SEER) database treated with surgery from 2003 to 2009. Potential predictors of OS were age, gender, race, tobacco use, oral cancer sub-sites, pathologic tumor stage and grade, pathologic nodal stage, extra-capsular invasion, clinical levels IV and V involvement, and adjuvant treatment selection. Weighted propensity scores for treatment were used to balance observed baseline characteristics between three treatment groups in order to reduce bias. Following primary surgery, patients underwent observation (56%), radiation alone (31%) or chemoradiation (13%). All tested predictors were statistically significant and included in our final nomogram. Most important predictor of OS was age, followed by pathologic tumor stage. SEER based-survival nomogram for OCSCC patients differs from published models derived from patients treated in a single or few academic treatment centers. An unexpected finding of patient age being the best OS predictor suggests that this factor may be more critical for the outcome than previously anticipated.

BACKGROUND: The prevalence of unruptured intracranial aneurysms (UIA) in females who smoke cigarettes and the association between smoking and hypertension with purely incidental UIAs have been unexplored.

OBJECTIVE: To obtain the prevalence of UIA among females and to assess the relationship between smoking and hypertension with a diagnosis of incidental UIAs.

METHODS: A nested case-control study from a cohort of female patients aged between 30 and 60 yr with a brain magnetic resonance angiography (MRA) between 2016 and 2018. Incidental UIAs were compared to patients with normal MRAs. Smoking was characterized as never or former/current smokers. A logistic regression was used to evaluate the association between smoking, hypertension, or both, with a diagnosis of incidental UIAs.

RESULTS: A total of 1977 patients had a brain MRA between 2016 and 2018. From 1572 nonsmoker patients, we encountered 30 with an UIA (prevalence: 1.9%). There were 405 patients with a positive smoking history, and 77 patients harbored an UIA (prevalence: 19%). Of 64 aneurysm patients and 130 random controls eligible for the case control, aneurysm patients were more likely to have a positive smoking history and hypertension compared with healthy controls (60% vs 18%, P ≤ .001; 44% vs 14%, P ≤ .001). A multivariable analysis demonstrated a significant association between a smoking history, hypertension, or both factors with an incidental UIA (odds ratio [OR] 5.8 CI 1.22-11.70; OR 3.8 CI 2.31-14.78; OR 12.6 CI 4.38-36.26; respectively).

CONCLUSION: Females who smoke cigarettes have a higher prevalence of UIAs than the general population. Smoking confers a higher risk for having a silent UIA, aggravated by hypertension. This population is an ideal target for potential screening.

The diagnosis of coronavirus disease 2019 (COVID-19) is confirmed by reverse transcription polymerase chain reaction. The utility of chest radiography (CXR) remains an evolving topic of discussion. Current reports of CXR findings related to COVID-19 contain varied terminology as well as various assessments of its sensitivity and specificity. This can lead to a misunderstanding of CXR reports and makes comparison between examinations and research studies challenging. With this need for consistency, we propose language for standardized CXR reporting and severity assessment of persons under investigation for having COVID-19, patients with a confirmed diagnosis of COVID-19, and patients who may have radiographic findings typical or suggestive of COVID-19 when the diagnosis is not suspected clinically. We recommend contacting the referring providers to discuss the likelihood of viral infection when typical or indeterminate features of COVID-19 pneumonia on CXR are present as an incidental finding. In addition, we summarize the currently available literature related to the use of CXR for COVID-19 and discuss the evolving techniques of obtaining CXR in COVID-19-positive patients. The recently published expert consensus statement on reporting chest computed tomography findings related to COVID-19, endorsed by the Radiological Society of North American (RSNA), the Society of Thoracic Radiology (STR), and American College of Radiology (ACR), serves as the framework for our proposal.

OBJECTIVE: To evaluate the diagnostic accuracy of split-bolus single-scan computed tomography angiography (CTA) protocol for evaluation of acute mesenteric ischemia and alternate diagnoses.

MATERIALS AND METHODS: In this IRB-approved, HIPAA-compliant retrospective study, consecutive patients from 21 October 2016 to 6 May 2018 evaluated for mesenteric ischemia with split-bolus CTA (a single scan in concurrent arterial and portal venous phase) in a single tertiary academic institution were included. Intravenous contrast was administered on weight-based basis. Quantitative and qualitative assessments of superior mesenteric artery (SMA) and superior mesenteric vein (SMV) attenuation and patency were performed by two independent reviewers. CT imaging findings were correlated with clinical reference outcomes.

RESULTS: One hundred fifty-four patients (age 66.3 ± 14.1 years, BMI 27.3 ± 6, 86 (56%) female) were included. CTA studies were performed with a volumetric CT dose index of 15.9 ± 5.5 mSv and dose length product of 1042.9 ± 389.4 mGy cm. Average intravenous contrast volume administered was 164.3 ± 12.1 cc. SMA attenuation was 263.6 ± 92.4HU, SMV was 190 ± 50.2HU. Qualitative assessment of SMA and SMV showed good opacification in all patients. 17/154 (11%) patients were diagnosed on CT with mesenteric ischemia; in 6/154 (4%), CTA studies were indeterminate; in 131/154 (85%), CTA confidently ruled out mesenteric ischemia. Alternate diagnoses were made in 38/154 (25%) patients. Using composite clinical outcomes as a reference standard, sensitivity of split-bolus CTA protocol for diagnosis of mesenteric ischemia is 100% (95% CI 79-100%), and specificity is 99% (95% CI 96-100%).

CONCLUSIONS: Split-bolus CTA has high sensitivity and specificity for diagnosis of acute mesenteric ischemia.

KEY POINTS: • Split-bolus CTA protocol for mesenteric ischemia has great diagnostic accuracy with lower radiation exposure and fewer images to interpret compared with standard multiphasic CTA.

OBJECTIVES: To evaluate the impact of patient positioning during CT-guided lung biopsy on patients' outcomes.

METHODS: In this retrospective, IRB-approved, HIPAA-compliant study, consecutive CT-guided lung biopsies performed on 5/1/2015-12/26/2017 were included. Correlation between incidence of pneumothorax, chest tube placement, pulmonary bleeding with patient, and procedure characteristics was evaluated. Lesion-trachea-table angle (LTTA) was defined as an angle between the lesion, trachea, and horizontal line parallel to the table. Lesion above trachea has a positive LTTA. Univariate and multivariate logistic regression analysis was performed.

RESULTS: A total of 423 biopsies in 409 patients (68 ± 11 years, 231/409, 56% female) were included in the study. Pneumothorax occurred in 83/423 (20%) biopsies with chest tube placed in 11/423 (3%) biopsies. Perilesional bleeding occurred in 194/423 (46%) biopsies and hemoptysis in 20/423 (5%) biopsies. Univariate analysis showed an association of pneumothorax with smaller lesions (p = 0.05), positive LTTA (p = 0.002), and lesions not attached to pleura (p = 0.026) with multivariate analysis showing lesion size and LTTA to be independent risk factors. Univariate analysis showed an association of increased pulmonary bleeding with smaller lesions (p < 0.001), no attachment to the pleura (p < 0.001), needle throw < 16 mm (p = 0.05), and a longer needle path (p < 0.001). Multivariate analysis showed lesion size, a longer needle path, and lesions not attached to the pleura to be independently associated with perilesional bleeding. Risk factors for hemoptysis were longer needle path (p = 0.002), no attachment to the pleura (p = 0.03), and female sex (p = 0.04).

CONCLUSIONS: Interventional radiologists can reduce the pneumothorax risk during the CT-guided biopsy by positioning the biopsy site below the trachea.

KEY POINTS: • Positioning patient with lesion to be below the trachea for the CT-guided lung biopsy results in lower rate of pneumothorax, as compared with the lesion above the trachea. • Positioning patient with lesion to be below the trachea for the CT-guided lung biopsy does not affect rate of procedure-associated pulmonary hemorrhage or hemoptysis.