Radionuclide shuntography for cerebrospinal fluid shunt flow evaluation in adults.

OBJECTIVE: Radionuclide shuntography (RS) performed using 99mTc-DTPA injected into the reservoir of CSF shunts enables evaluation of CSF flow for suspected shunt malfunctions. The goal of this study was to report the authors' institutional experience with RS and evaluate its utility and associated complications. METHODS: The authors retrospectively reviewed all RS studies performed between November 2003 and June 2022. Patients with shunted hydrocephalus who were ≥ 18 years of age were included. Patients undergoing RS for evaluation of Ommaya reservoirs were excluded. Demographics, hydrocephalus etiology, presenting symptoms, study results, subsequent management, complications, and intraoperative diagnoses were recorded. Chi-square tests were reported for categorical variables and standard 2 × 2 contingency methods were used for sensitivity/specificity analysis. RESULTS: The authors identified 211 RS procedures performed in 142 patients. The mean age at procedure was 55.6 ± 20.9 years (mean ± SD). Normal pressure hydrocephalus was the most common hydrocephalus etiology (37.0%), followed by congenital malformations (26.1%) and idiopathic intracranial hypertension (15.6%). Successful radionuclide injection was achieved in 207 studies (98.1%). Shunt patency was confirmed in 63.8% of successful injections, whereas malfunction was demonstrated in 27.1% and abnormally slow flow was seen in 9.2%. RS studies demonstrating shunt malfunction were more likely to result in subsequent revisions than were studies showing patency (86.6% vs 2.9%; p < 0.0001). The overall sensitivity and specificity of RS for detecting shunt malfunction was 92.3% and 96.2%, respectively. The median follow-up time was 29 months, with 151 cases having ≥ 6 months of follow-up. There were no complications or infections attributable to RS in this cohort. CONCLUSIONS: RS is a useful and safe tool in the workup of shunt malfunction.

Don't judge a book by its cover: a case report of apolipoprotein A-IV cardiac amyloidosis.

Background: To date, at least 20 different amyloidogenic proteins have been documented. Growing evidence suggests that despite being part of the universal amyloid proteome, apolipoprotein A-IV can be amyloidogenic, accounting for less than 1% of cases. Case summary: A 75-year-old woman was admitted for paroxysmal nocturnal dyspnoea and intermittent exertional shortness of breath and was found to be in acute heart failure. The patient underwent intravenous diuretic therapy and was discharged after decongestion. She then underwent a battery of outpatient tests to determine aetiology of her heart failure. Cardiac magnetic resonance imaging showed severe concentric left ventricular hypertrophy and diffuse late gadolinium enhancement, concerning for amyloidosis, but serologic evaluation for amyloidogenic light chain (AL) amyloidosis was negative. Tc 99m pyrophosphate (PYP) scan showed Grade 2 uptake at 1 h that was only moderately suggestive of transthyretin (TTR) amyloidosis. She ultimately received a right heart catheterization and endomyocardial biopsy, which showed apolipoprotein A-IV amyloid deposition within Congo red-positive areas of the endomyocardial specimen. The patient continues to report dyspnoea on exertion but has avoided additional heart failure admissions with intensification of her diuretic regimen. Discussion: In this case, nuclear PYP scan to evaluate for TTR amyloidosis demonstrated focal PYP uptake, but endomyocardial biopsy demonstrated apolipoprotein A-IV deposition without evidence of TTR amyloidosis. Our case increases knowledge of this rare form of amyloidosis, suggests that it may result in false positive nuclear PYP results, and highlights the importance of its evaluation, particularly in circumstances in which investigations do not reveal definitive evidence of AL or TTR amyloidosis.

The utility of [18F]Fluciclovine PET/CT in Evaluating Nonmetastatic Castrate-Resistant Prostate Cancer Patients (nmCRPCp): diagnostic performance and impact on management.

OBJECTIVE: To evaluate the role of [18F]Fluciclovine PET/CT scan in restaging nmCRPCp and its impact on management. METHODS AND MATERIALS: This retrospective study included all patients with nonmetastatic castrate-resistant prostate cancer, who underwent [18F]Fluciclovine PET/CT scans for restaging who had concern for disease progression. Two radiologists independently reviewed the PET/CT studies, assigned an overall impression, and reported the site and number of radiotracer activities in consensus and impact on management was recorded. Available tissue diagnosis and/or six-month clinical and imaging follow-up were used as reference standards. RESULTS: Thirty-five patients were included in this study. At least one lesion was detected in 73% (26/35) of the scans. Management changed in 71% (25/35) of patients, (22 positives and three negative scans). 26.9% (7/26) of patients were found to have an oligometastatic disease. Based on the reference standards, the diagnostic performance of [18F]Fluciclovine PET/CT in detecting recurrence in nmCRCP has 86%, sensitivity, 83% specificity, 96.1% PPV, and 55.5% NPV. There was no relationship between the Gleason score and a positive PET/CT scan in our patient population. CONCLUSION: Detecting the source of recurrence is challenging in nmCRCP patients when conventional imaging fails. Given the high PPV, sensitivity, and specificity, [18F]Fluciclovine PET/CT can be used instead of conventional imaging as a first-line choice due to its superiority over bone scan and added value of detecting soft tissue metastasis regardless of the initial Gleason score. ADVANCES IN KNOWLEDGE: The study highlights the added value of [18F]Fluciclovine PET/CT in detecting soft tissue metastasis regardless of the initial Gleason score, which is not possible with conventional imaging such as bone scans.The study highlights the potential role of [18F]Fluciclovine PET/CT guiding management change for nonmetastatic castrate-resistant prostate cancer patients, particularly those with oligometastatic disease.

Case report: Multimodality imaging of unusual coronary to pulmonary collaterals in chronic thromboembolic pulmonary hypertension.

We present unusual coronary-pulmonary collaterals in a 65-year-old CTEPH patient. Perfusion mapping of a dual-energy computed tomography (DECT) study revealed areas of right lung that were minimally perfused despite unilateral occlusion of the right pulmonary artery, leading to the discovery of coronary-pulmonary collaterals via invasive coronary angiography. Pulmonary thromboendarterectomy removed the clot en-bloc. Post-surgery DECT and catheterization confirmed restoration of pulmonary arterial circulation and excellent hemodynamic response. Here, suggestion of perfusion to a proximally obstructed lung with DECT helped to document the presence of rarely documented coronary-pulmonary artery collaterals.

ACR Appropriateness Criteria® Pretreatment Detection, Surveillance, and Staging of Prostate Cancer: 2022 Update.

Prostate cancer is second leading cause of death from malignancy after lung cancer in American men. The primary goal during pretreatment evaluation of prostate cancer is disease detection, localization, establishing disease extent (both local and distant), and evaluating aggressiveness, which are the driving factors of patient outcomes such as recurrence and survival. Prostate cancer is typically diagnosed after the recognizing elevated serum prostate-specific antigen level or abnormal digital rectal examination. Tissue diagnosis is obtained by transrectal ultrasound-guided biopsy or MRI-targeted biopsy, commonly with multiparametric MRI without or with intravenous contrast, which has recently been established as standard of care for detecting, localizing, and assessing local extent of prostate cancer. Although bone scintigraphy and CT are still typically used to detect bone and nodal metastases in patients with intermediate- or high-risk prostate cancer, novel advanced imaging modalities including prostatespecific membrane antigen PET/CT and whole-body MRI are being more frequently utilized for this purpose with improved detection rates. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Staging of Renal Cell Carcinoma: 2022 Update.

Renal cell carcinoma is a complex group of highly heterogenous renal tumors demonstrating variable biological behavior. Pretreatment imaging of renal cell carcinoma involves accurate assessment of the primary tumor, presence of nodal, and distant metastases. CT and MRI are the key imaging modalities used in the staging of renal cell carcinoma. Important imaging features that impact treatment include tumor extension into renal sinus and perinephric fat, involvement of pelvicalyceal system, infiltration into adrenal gland, involvement of renal vein and inferior vena cava, as well as the presence of metastatic adenopathy and distant metastases. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

The comorbidity of depression and neurocognitive disorder in persons with HIV infection: call for investigation and treatment.

Depression and neurocognitive disorder continue to be the major neuropsychiatric disorders affecting persons with HIV (PWH). The prevalence of major depressive disorder is two to fourfold higher among PWH than the general population (∼6.7%). Prevalence estimates of neurocognitive disorder among PWH range from 25 to over 47% - depending upon the definition used (which is currently evolving), the size of the test battery employed, and the demographic and HIV disease characteristics of the participants included, such as age range and sex distribution. Both major depressive disorder and neurocognitive disorder also result in substantial morbidity and premature mortality. However, though anticipated to be relatively common, the comorbidity of these two disorders in PWH has not been formally studied. This is partly due to the clinical overlap of the neurocognitive symptoms of these two disorders. Both also share neurobehavioral aspects - particularly apathy - as well as an increased risk for non-adherence to antiretroviral therapy. Shared pathophysiological mechanisms potentially explain these intersecting phenotypes, including neuroinflammatory, vascular, and microbiomic, as well as neuroendocrine/neurotransmitter dynamic mechanisms. Treatment of either disorder affects the other with respect to symptom reduction as well as medication toxicity. We present a unified model for the comorbidity based upon deficits in dopaminergic transmission that occur in both major depressive disorder and HIV-associated neurocognitive disorder. Specific treatments for the comorbidity that decrease neuroinflammation and/or restore associated deficits in dopaminergic transmission may be indicated and merit study.

A VISION Substudy of Reader Agreement on 68Ga-PSMA-11 PET/CT Scan Interpretation to Determine Patient Eligibility for 177Lu-PSMA-617 Radioligand Therapy.

[ 68Ga]Ga-PSMA-11 ( 68Ga-PSMA-11) is used to identify prostate-specific membrane antigen (PSMA)-positive tumors on PET scans. In the VISION study, 68Ga-PSMA-11 was used to determine the eligibility of patients with metastatic castration-resistant prostate cancer for treatment with [177Lu]Lu-PSMA-617 (177Lu-PSMA-617), based on predefined read criteria. This substudy aimed to investigate the interreader variability and intrareader reproducibility of visual assessments of 68Ga-PSMA-11 PET/CT scans using the VISION read criteria and evaluate the agreement between read results for this and the VISION study. Methods: In VISION, 68Ga-PSMA-11 PET/CT scans were centrally read as inclusion cases if they had at least 1 PSMA-positive lesion and no PSMA-negative lesions that fulfilled the exclusion criteria. In this substudy, 125 PET/CT scans (75 inclusion and 50 exclusion cases) were randomly selected from VISION and retrospectively assessed by 3 independent central readers. A random subset of 20 cases (12 inclusion and 8 exclusion cases) was recoded for assessment of intrareader reproducibility. Classification of cases as inclusion or exclusion cases was based on the VISION read criteria. Overall interreader variability was assessed by Fleiss κ-statistics, and pairwise variability and intrareader reproducibility were assessed by Cohen κ-statistics. Results: For interreader variability, the readers agreed on 77% of cases (overall average agreement rate, 0.85; Fleiss κ, 0.60 [95% CI, 0.50-0.70]). The pairwise agreement rate was 0.82, 0.88, and 0.84, and the corresponding Cohen κ was 0.54 (95% CI, 0.38-0.71), 0.67 (95% CI, 0.52-0.83), and 0.59 (95% CI, 0.43-0.75), respectively. For intrareader reproducibility, the agreement rate was 0.90, 0.90, and 0.95, and the corresponding Cohen κ was 0.78 (95% CI, 0.49-0.99), 0.76 (95% CI, 0.46-0.99), and 0.89 (95% CI, 0.67-0.99), respectively. The number of actual VISION inclusion cases out of the total number of cases scored as inclusion in this substudy was 71 of 93 (agreement rate, 0.76; 95% CI, 0.66-0.85) for reader 1, 70 of 88 (0.80; 0.70-0.87) for reader 2, and 73 of 96 (0.76; 0.66-0.84) for reader 3. All readers agreed on 66 of 75 VISION inclusion cases. Conclusion: Moderate-to-substantial interreader agreement and substantial-to-almost perfect intrareader reproducibility for 68Ga-PSMA-11 PET/CT scan assessment using the VISION read criteria were observed. The read rules applied in VISION can be readily learned and demonstrate good reproducibility.

Potential Prognostic Value of Native T1 in Pulmonary Hypertension Patients.

Native T1, extracellular volume fraction (ECV), and late gadolinium enhancement (LGE) characterize myocardial tissue and relate to patient prognosis in a variety of diseases, including pulmonary hypertension. The purpose of this study was to evaluate if left ventricle (LV) fibrosis measurements have prognostic value for cardiac outcomes in pulmonary hypertension subgroups. 54 patients with suspected pulmonary hypertension underwent right-heart catheterization and were classified into pulmonary hypertension subgroups: pre-capillary component (PreCompPH) and isolated post-capillary (IpcPH). Cardiac magnetic resonance imaging (MRI) scans were performed with the acquisition of balanced cine steady-state free precession, native T1, and LGE pulse sequences to measure cardiac volumes and myocardial fibrosis. Associations between cardiac events and cardiac MRI measurements were analyzed within PreCompPH and IpcPH patients. IpcPH: LV native T1 was higher in patients who experienced a cardiac event within two years vs. those who did not. In patients with LV native T1 > 1050 ms, the rate of cardiac events was higher. ECV and quantitative LGE did not differ between groups. PreCompPH: native T1, ECV, and quantitative/qualitative LGE did not differ between patients who experienced a cardiac event within two years vs. those who did not. LV native T1 may have potential value for forecasting cardiac events in IpcPH, but not in PreCompPH, patients.

Differences in referral to a chronic thromboembolic pulmonary hypertension center following acute pulmonary embolism: a locoregional experience.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a treatable complication of acute pulmonary embolism (PE). Identification of factors that impact referral to a comprehensive CTEPH center may improve disease awareness and patient outcomes. We conducted a study of patients with acute PE. Cases were identified through a natural language processing algorithm. ICD coding was used to assess clinical documentation for dyspnea or CTEPH placed at least 90 days after their acute PE diagnosis. We analyzed characteristics of patients who were referred vs. not referred, as well as referral patterns for "at risk" patients. 2454 patients with acute PE were identified, of which 4.9% (120/2454) were referred for CTEPH evaluation. Patients who were not referred were older (61 vs. 54 years, p < 0.001), had higher rates of cancer (28% vs. 10%, p < 0.001), and lived further from the referral center (9.1 miles vs. 6.7 miles, p = 0.03). Of 175 patients identified as "at risk," 12% (21/175) were referred. In the 'at risk' cohort, distance from referral center among referred and not referred was significant (5.7 miles vs. 8.8 miles, p = 0.04). There were low rates of referral to CTEPH center in post-PE patients, and in patients with symptoms who may be at higher risk of CTEPH. Age, co-morbid conditions, distance from comprehensive center, and presence of a primary care provider contribute to differences in referral to a comprehensive CTEPH center. Clinician education about CTEPH is important to ensure optimal care to patients with or at risk for chronic complications of acute PE.

Systolic reverse flow derived from 4D flow cardiovascular magnetic resonance in bicuspid aortic valve is associated with aortic dilation and aortic valve stenosis: a cross sectional study in 655 subjects.

BACKGROUND: Bicuspid aortic valve (BAV) disease is associated with increased risk of aortopathy. In addition to current intervention guidelines, BAV mediated changes in aortic 3D hemodynamics have been considered as risk stratification measures. We aimed to evaluate the association of 4D flow cardiovascular magnetic resonance (CMR) derived voxel-wise aortic reverse flow with aortic dilation and to investigate the role of aortic valve regurgitation (AR) and stenosis (AS) on reverse flow in systole and diastole. METHODS: 510 patients with BAV (52 ± 14 years) and 120 patients with trileaflet aortic valve (TAV) (61 ± 11 years) and mid-ascending aorta diameter (MAAD) > 35 mm who underwent CMR including 4D flow CMR were retrospectively included. An age and sex-matched healthy control cohort (n = 25, 49 ± 12 years) was selected. Voxel-wise reverse flow was calculated in the aorta and quantified by the mean reverse flow in the ascending aorta (AAo) during systole and diastole. RESULTS: BAV patients without AS and AR demonstrated significantly increased systolic and diastolic reverse flow (222% and 13% increases respectively, p < 0.01) compared to healthy controls and also had significantly increased systolic reverse flow compared to TAV patients with aortic dilation (79% increase, p < 0.01). In patients with isolated AR, systolic and diastolic AAo reverse flow increased significantly with AR severity (c = - 83.2 and c = - 205.6, p < 0.001). In patients with isolated AS, AS severity was associated with an increase in both systolic (c = - 253.1, p < 0.001) and diastolic (c = - 87.0, p = 0.02) AAo reverse flow. Right and left/right and non-coronary fusion phenotype showed elevated systolic reverse flow (> 17% increase, p < 0.01). Right and non-coronary fusion phenotype showed decreased diastolic reverse flow (> 27% decrease, p < 0.01). MAAD was an independent predictor of systolic (p < 0.001), but not diastolic, reverse flow (p > 0.1). CONCLUSION: 4D flow CMR derived reverse flow associated with BAV was successfully captured even in the absence of AR or AS and in comparison to TAV patients with aortic dilation. Diastolic AAo reverse flow increased with AR severity while AS severity strongly correlated with increased systolic reverse flow in the AAo. Additionally, increasing MAAD was independently associated with increasing systolic AAo reverse flow. Thus, systolic AAo reverse flow may be a valuable metric for evaluating disease severity in future longitudinal outcome studies.

Fully-automated deep learning-based flow quantification of 2D CINE phase contrast MRI.

OBJECTIVES: Time-resolved, 2D-phase-contrast MRI (2D-CINE-PC-MRI) enables in vivo blood flow analysis. However, accurate vessel contour delineation (VCD) is required to achieve reliable results. We sought to evaluate manual analysis (MA) compared to the performance of a deep learning (DL) application for fully-automated VCD and flow quantification and corrected semi-automated analysis (corSAA). METHODS: We included 97 consecutive patients (age = 52.9 ± 16 years, 41 female) with 2D-CINE-PC-MRI imaging on 1.5T MRI systems at sinotubular junction (STJ), and 28/97 also received 2D-CINE-PC at main pulmonary artery (PA). A cardiovascular radiologist performed MA (reference) and corSAA (built-in tool) in commercial software for all cardiac time frames (median: 20, total contours per analysis: 2358 STJ, 680 PA). DL-analysis automatically performed VCD, followed by net flow (NF) and peak velocity (PV) quantification. Contours were compared using Dice similarity coefficients (DSC). Discrepant cases (> ± 10 mL or > ± 10 cm/s) were reviewed in detail. RESULTS: DL was successfully applied to 97% (121/125) of the 2D-CINE-PC-MRI series (STJ: 95/97, 98%, PA: 26/28, 93%). Compared to MA, mean DSC were 0.91 ± 0.02 (DL), 0.94 ± 0.02 (corSAA) at STJ, and 0.85 ± 0.08 (DL), 0.93 ± 0.02 (corSAA) at PA; this indicated good to excellent DL-performance. Flow quantification revealed similar NF at STJ (p = 0.48) and PA (p > 0.05) between methods while PV assessment was significantly different (STJ: p < 0.001, PA: p = 0.04). A detailed review showed noisy voxels in MA and corSAA impacted PV results. Overall, DL analysis compared to human assessments was accurate in 113/121 (93.4%) cases. CONCLUSIONS: Fully-automated DL-analysis of 2D-CINE-PC-MRI provided flow quantification at STJ and PA at expert level in > 93% of cases with results being available instantaneously. KEY POINTS: • Deep learning performed flow quantification on clinical 2D-CINE-PC series at the sinotubular junction and pulmonary artery at the expert level in > 93% of cases. • Location detection and contouring of the vessel boundaries were performed fully-automatic with results being available instantaneously compared to human assessments which approximately takes three minutes per location. • The evaluated tool indicates usability in daily practice.

A Framework for Harmonization of Radiomics Data for Multicenter Studies and Clinical Trials.

PURPOSE: Variability in computed tomography images intrinsic to individual scanners limits the application of radiomics in clinical and research settings. The development of reproducible and generalizable radiomics-based models to assess lesions requires harmonization of data. The purpose of this study was to develop, test, and analyze the efficacy of a radiomics data harmonization model. MATERIALS AND METHODS: Radiomic features from biopsy-proven untreated hepatic metastasis (N = 380) acquired from 167 unique patients with pancreatic, colon, and breast cancers were analyzed. Radiomic features from volume-match 551 samples of normal liver tissue and 188 hepatic cysts were included as references. A novel linear mixed effect model was used to identify effects associated with lesion size, tissue type, and scanner model. Six separate machine learning models were then used to test the effectiveness of radiomic feature harmonization using multivariate analysis. RESULTS: Proposed model identifies and removes scanner-associated effects while preserving cancer-specific functional dependence of radiomic features on the tumor size. Data harmonization improves the performance of classification models by reducing the scanner-associated variability. For example, the multiclass logistic regression model, LogitBoost, demonstrated the improvement in sensitivity in the range from 15% to 40% for each type of liver metastasis, whereas the overall model accuracy and the kappa coefficient increased by 5% and 8% accordingly. CONCLUSION: The model removed scanner-associated effects while preserving cancer-specific functional dependence of radiomic features.

Utilization of a cloud-based radiology analytics platform to monitor imaging volumes at a large tertiary center.

Rationale and objective: In this study, we evaluate the ability of a novel cloud-based radiology analytics platform to continuously monitor imaging volumes at a large tertiary center following institutional protocol and policy changes. Materials and methods: We evaluated response to environmental factors through the lens of the COVID-19 pandemic. Analysis involved 11 CT/18 MR imaging systems at a large tertiary center. A vendor neutral, cloud-based analytics tool (CBRAP) was used to retrospectively collect information via DICOM headers on imaging exams between Oct. 2019 to Aug. 2021. Exams were stratified by modality (CT or MRI) and organized by body region. Pre-pandemic scan volumes (Oct 2019-Feb. 2010) were compared with volumes during/after two waves of COVID-19 in Illinois (Mar. to May 2020 & Oct. to Dec. 2020) using a t-test or Mann-Whitney U test. Results: The CBRAP was able to analyze 169,530 CT and 110,837 MR images, providing a detailed snapshot of baseline and post-pandemic CT and MR imaging across the radiology enterprise at our tertiary center. The CBRAP allowed for further subdivision in its reporting, showing monthly trends in average scan volumes specifically in the head, abdomen, spine, MSK, thorax, neck, GU system, or breast. Conclusion: The CBRAP retrieved data for 300,000 + imaging exams across multiple modalities at a large tertiary center in a highly populated, urban environment. The ability to analyze large imaging volumes across multiple waves of COVID-19 and evaluate quality-improvement endeavors/imaging protocol changes displays the usefulness of the CBRAP as an advanced imaging analytics tool.

Combined modality PET/MR for the detection of severe large vessel vasculitis.

BACKGROUND: Large vessel vasculitis (LVV) can be characterized based on symptom severity, and this characterization helps clinicians decide upon treatment approach. Our aim was to compare the imaging findings of combined modality positron emission tomography/magnetic resonance (PET/MR) and inflammatory markers between severe and non-severe LVV. A retrospective query was performed to identify all patients with LVV who underwent PET/MR at our institution between January 2015 and January 2021. RESULTS: Eleven patients (nine females; age 62.2 ± 16.4 years) underwent 15 PET/MR scans. Positivity was defined by findings indicative of active LVV on each modality: PET positive if vessel metabolic activity > liver metabolic activity; MR positive if wall thickening or contrast enhancement. When positive PET or positive MR findings were considered a positive scan, LVV patients with severe disease (n = 9 scans) showed a higher number of positive scans (n = 9) compared to the number of positive scans in non-severe patients (n = 3) (p < 0.05). The sensitivity and specificity for the detection of severe LVV were 1.00 and 0.50, respectively. When only the presence of both positive PET and positive MR findings were considered a positive scan, inflammatory marker levels were not significantly different between severe and non-severe LVV groups (severe: erythrocyte sedimentation rate (ESR) = 9.8 ± 10.6 mm/h; C-reactive protein (CRP) = 0.6 ± 0.4 mg/dL) (non-severe: ESR = 14.3 ± 22.4 mm/h; CRP = 0.5 ± 0.6 mg/dL). Blood- and liver-normalized maximum standardized uptake values were not significantly different between severe and non-severe patients (1.4 ± 0.3 vs 1.5 ± 0.4; 1.1 ± 0.4 vs 1.0 ± 0.3, respectively). CONCLUSIONS: Because of the differences observed, PET/MR appears to be better suited to facilitate the characterization of LVV as severe or non-severe compared to inflammatory marker measurements and quantitative measurements of metabolic activity. Qualitative assessment of PET and MR positivity by 18F-fluorodeoxyglucose PET/MR may be able to supplement clinical symptoms-based LVV classification decisions and may be helpful when clinical symptoms overlap with other disease processes.

Use of soil moisture active passive satellite data and WorldClim 2.0 data to predict the potential distribution of visceral leishmaniasis and its vector Lutzomyia longipalpis in Sao Paulo and Bahia states, Brazil.

Visceral leishmaniasis (VL) is a neglected tropical disease transmitted by Lutzomyia longipalpis, a sand fly widely distributed in Brazil. Despite efforts to strengthen national control programs reduction in incidence and geographical distribution of VL in Brazil has not yet been successful; VL is in fact expanding its range in newly urbanized areas. Ecological niche models (ENM) for use in surveillance and response systems may enable more effective operational VL control by mapping risk areas and elucidation of eco-epidemiologic risk factors. ENMs for VL and Lu. longipalpis were generated using monthly WorldClim 2.0 data (30-year climate normal, 1-km spatial resolution) and monthly soil moisture active passive (SMAP) satellite L4 soil moisture data. SMAP L4 Global 3-hourly 9-km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data V004 were obtained for the first image of day 1 and day 15 (0:00-3:00 hour) of each month. ENM were developed using MaxEnt software to generate risk maps based on an algorithm for maximum entropy. The jack-knife procedure was used to identify the contribution of each variable to model performance. The three most meaningful components were used to generate ENM distribution maps by ArcGIS 10.6. Similar patterns of VL and vector distribution were observed using SMAP as compared to WorldClim 2.0 models based on temperature and precipitation data or water budget. Results indicate that direct Earth-observing satellite measurement of soil moisture by SMAP can be used in lieu of models calculated from classical temperature and precipitation climate station data to assess VL risk.

4D flow MRI derived aortic hemodynamics multi-year follow-up in repaired coarctation with bicuspid aortic valve.

PURPOSE: The purpose of this study was to investigate the relationships between hemodynamic parameters and longitudinal changes in aortic dimensions on four-dimensional (4D) flow magnetic resonance imaging (MRI) in patients with bicuspid aortic valve (BAV) and repaired coarctation. MATERIALS AND METHODS: The study retrospectively included patients with BAV and childhood coarctation repair who had at least two cardiothoracic MRI examinations including 4D flow MRI at baseline and follow-up. Analysis included the calculation of aortic peak velocities, wall shear stress (WSS), pulse wave velocity (PWV), aortic dimensions and annual growth rates. Differences between examinations were assessed using paired t-test or Wilcoxon signed rank test. Relationships between growth rate and 4D flow metrics were assessed using Pearson or Spearman correlation tests. RESULTS: The cohort included 15 patients (mean age 35 ± 8 [SD] years, 9 men) with a median follow-up time of 3.98 years (Q1: 2.10; Q3: 4.96). There were no significant differences in aortic mean WSS, peak velocities, and PWV between baseline and follow-up values. Greater baseline peak velocities at the site of the coarctation were strongly associated with aortic narrowing (follow-up vs. baseline diameter) at coarctation zone (r = -0.64; P = 0.010) and moderately in descending aorta (r = -0.53; P = 0.042). In addition, increased baseline WSS in the aortic arch was strongly related with narrowing of the coarctation zone at follow-up (r = -0.64, P = 0.011). CONCLUSION: Measures of aortic hemodynamics and aortic WSS are stable over time in patients with BAV with coarctation repair. Increased peak velocity was associated with a progressive narrowing at the site of the coarctation repair.

Multimodal Presurgical Evaluation of Medically Refractory Focal Epilepsy in Adults: An Update for Radiologists.

Surgery is a potentially curative treatment option for patients with medically refractory focal epilepsy. Advanced neuroimaging modalities often improve surgical outcomes by contributing key information during the highly individualized surgical planning process and intraoperative localization. Hence, neuroradiologists play an integral role in the multidisciplinary management team. In this review, we initially present the conceptual background and practical framework of the presurgical evaluation process, including a description of the surgical treatment approaches used for medically refractory focal epilepsy in adults. This background is followed by an overview of the advanced modalities commonly used during the presurgical workup at level IV epilepsy centers, including diffusion imaging techniques, blood oxygenation level-dependent functional MRI (fMRI), PET, SPECT, and subtraction ictal SPECT, and by introductions to 7-T MRI and electrophysiologic techniques including electroencephalography and magnetoencephalography. We also provide illustrative case examples of multimodal neuroimaging including PET/MRI, PET/MRI-diffusion-tensor imaging (DTI), subtraction ictal SPECT, and image-guided stereotactic planning with fMRI-DTI.

Deep learning-based velocity antialiasing of 4D-flow MRI.

PURPOSE: To develop a convolutional neural network (CNN) for the robust and fast correction of velocity aliasing in 4D-flow MRI. METHODS: This study included 667 adult subjects with aortic 4D-flow MRI data with existing velocity aliasing (n = 362) and no velocity aliasing (n = 305). Additionally, 10 controls received back-to-back 4D-flow scans with systemically varied velocity-encoding sensitivity (vencs) at 60, 100, and 175 cm/s. The no-aliasing data sets were used to simulate velocity aliasing by reducing the venc to 40%-70% of the original, alongside a ground truth locating all aliased voxels (153 training, 152 testing). The 152 simulated and 362 existing aliasing data sets were used for testing and compared with a conventional velocity antialiasing algorithm. Dice scores were calculated to quantify CNN performance. For controls, the venc 175-cm/s scans were used as the ground truth and compared with the CNN-corrected venc 60 and 100 cm/s data sets RESULTS: The CNN required 176 ± 30 s to perform compared with 162 ± 14 s for the conventional algorithm. The CNN showed excellent performance for the simulated data compared with the conventional algorithm (median range of Dice scores CNN: [0.89-0.99], conventional algorithm: [0.84-0.94], p < 0.001, across all simulated vencs) and detected more aliased voxels in existing velocity aliasing data sets (median detected CNN: 159 voxels [31-605], conventional algorithm: 65 [7-417], p < 0.001). For controls, the CNN showed Dice scores of 0.98 [0.95-0.99] and 0.96 [0.87-0.99] for venc = 60 cm/s and 100 cm/s, respectively, while flow comparisons showed moderate-excellent agreement. CONCLUSION: Deep learning enabled fast and robust velocity anti-aliasing in 4D-flow MRI.

Free-breathing gradient recalled echo-based CMR in a swine heart failure model.

In swine models, there are well-established protocols for creating a closed-chest myocardial infarction (MI) as well as protocols for characterization of cardiac function with cardiac magnetic resonance (CMR). This methods manuscript outlines a novel technique in CMR data acquisition utilizing smart-signal gradient recalled echo (GRE)-based array sequences in a free-breathing swine heart failure model allowing for both high spatial and temporal resolution imaging. Nine male Yucatan mini swine weighing 48.7 ± 1.6 kg at 58.2 ± 3.1 weeks old underwent the outlined imaging protocol before and 1-month after undergoing closed chest left anterior descending coronary artery (LAD) occlusion/reperfusion. The left ventricular ejection fraction (LVEF) at baseline was 59.3 ± 2.4% and decreased to 48.1 ± 3.7% 1-month post MI (P = 0.029). The average end-diastolic volume (EDV) at baseline was 55.2 ± 1.7 ml and increased to 74.2 ± 4.2 ml at 1-month post MI (P = 0.001). The resulting images from this novel technique and post-imaging analysis are presented and discussed. In a Yucatan swine model of heart failure via closed chest left anterior descending coronary artery (LAD) occlusion/reperfusion, we found that CMR with GRE-based array sequences produced clinical-grade images with high spatial and temporal resolution in the free-breathing setting.