Browsing by Author "Besa, Cecilia"
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- ItemA Survey on Deep Learning and Explainability for Automatic Report Generation from Medical Images(2022) Messina, Pablo; Pino, Pablo; Parra Santander, Denis; Soto Arriaza, Álvaro Marcelo; Besa, Cecilia; Uribe Arancibia, Sergio A.; Andía Kohnenkampf, Marcelo Edgardo; Tejos Núñez, Cristián Andrés; Prieto Vásquez, Claudia; Capurro, Daniel
- ItemFast and accessible T2 mapping using off-resonance corrected DESPOT2 with application to 3D prostate(2024) Coronado, Ronal; Castillo-Passi, Carlos; Besa, Cecilia; Irarrazaval, PabloPurpose: Most T1 and T2 mapping take long acquisitions or needs specialized sequences not widely accessible on clinical scanners. An available solution is DESPOT1/T2 (Driven equilibrium single pulse observation of T1/T2). DESPOT1/T2 uses Spoiled gradient-echo (SPGR) and balanced Steady-State Free Precession (bSSFP) sequences, offering an accessible and reliable way for 3D accelerated T1/T2 mapping. However, bSSFP is prone to offresonance artifacts, limiting the application of DESPOT2 in regions with high susceptibility contrasts, like the prostate. Our proposal, DESPO+, employs the full bSSFP and SPGR models with a dictionary-based method to reconstruct 3D T1/T2 maps in the prostate region without off-resonance banding. Methods: DESPO+ modifies the bSSFP acquisition of the original variable flip angle DESPOT2. DESPO+ uses variable repetition and echo times, employing a dictionary-based method of the full bSSFP and SPGR models to reconstruct T1, T2, and Proton Density (PD) simultaneously. The proposed DESPO+ method underwent testing through simulations, T1/T2 phantoms, and on fourteen healthy subjects. Results: The results reveal a significant reduction in T2 map banding artifacts compared to the original DESPOT2 method. DESPO+ approach reduced T2 errors by up to seven times compared to DESPOT2 in simulations and phantom experiments. We also synthesized in-vivo T1-weighted/T2-weighted images from the acquired maps using a spin-echo model to verify the map's quality when lacking a reference. For in-vivo imaging, the synthesized images closely resemble those from the clinical MRI protocol, reducing scan time by around 50% compared to traditional spin-echo T1-weighted/T2-weighted acquisitions. Conclusion: DESPO+ provides an off-resonance insensitive and clinically available solution, enabling highresolution 3D T1/T2 mapping and synthesized T1-weighted/T2-weighted images for the entire prostate, all achieved within a short scan time of 3.6 min, similar to DESPOT1/T2.
- ItemIntestinal Obstruction as Manifestation of a Multifocal Colonic Endometriosis(ELSEVIER SCIENCE INC, 2011) Caselli, Gino; Besa, Cecilia; Pulgar, Dahiana
- ItemLiver PDFF estimation using a multi-decoder water-fat separation neural network with a reduced number of echoes(2023) Meneses, Juan Pablo; Arrieta, Cristobal; della Maggiora, Gabriel; Besa, Cecilia; Urbina, Jesus; Arrese, Marco; Gana, Juan Cristobal; Galgani, Jose E.; Tejos, Cristian; Uribe, SergioObjectiveTo accurately estimate liver PDFF from chemical shift-encoded (CSE) MRI using a deep learning (DL)-based Multi-Decoder Water-Fat separation Network (MDWF-Net), that operates over complex-valued CSE-MR images with only 3 echoes.MethodsThe proposed MDWF-Net and a U-Net model were independently trained using the first 3 echoes of MRI data from 134 subjects, acquired with conventional 6-echoes abdomen protocol at 1.5 T. Resulting models were then evaluated using unseen CSE-MR images obtained from 14 subjects that were acquired with a 3-echoes CSE-MR pulse sequence with a shorter duration compared to the standard protocol. Resulting PDFF maps were qualitatively assessed by two radiologists, and quantitatively assessed at two corresponding liver ROIs, using Bland Altman and regression analysis for mean values, and ANOVA testing for standard deviation (STD) (significance level: .05). A 6-echo graph cut was considered ground truth.ResultsAssessment of radiologists demonstrated that, unlike U-Net, MDWF-Net had a similar quality to the ground truth, despite it considered half of the information. Regarding PDFF mean values at ROIs, MDWF-Net showed a better agreement with ground truth (regression slope = 0.94, R-2 = 0.97) than U-Net (regression slope = 0.86, R-2 = 0.93). Moreover, ANOVA post hoc analysis of STDs showed a statistical difference between graph cuts and U-Net (p < .05), unlike MDWF-Net (p = .53).ConclusionMDWF-Net showed a liver PDFF accuracy comparable to the reference graph cut method, using only 3 echoes and thus allowing a reduction in the acquisition times.
- ItemMRI-Based Surrogate Imaging Markers of Aggressiveness in Prostate Cancer: Development of a Machine Learning Model Based on Radiomic Features(2023) Dominguez, Ignacio; Rios-Ibacache, Odette; Caprile, Paola; Gonzalez, Jose; San Francisco, Ignacio F.; Besa, CeciliaThis study aimed to develop a noninvasive Machine Learning (ML) model to identify clinically significant prostate cancer (csPCa) according to Gleason Score (GS) based on biparametric MRI (bpMRI) radiomic features and clinical information. Methods: This retrospective study included 86 adult Hispanic men (60 & PLUSMN; 8.2 years, median prostate-specific antigen density (PSA-D) 0.15 ng/mL2) with PCa who underwent prebiopsy 3T MRI followed by targeted MRI-ultrasound fusion and systematic biopsy. Two observers performed 2D segmentation of lesions in T2WI/ADC images. We classified csPCa (GS & GE; 7) vs. non-csPCa (GS = 6). Univariate statistical tests were performed for different parameters, including prostate volume (PV), PSA-D, PI-RADS, and radiomic features. Multivariate models were built using the automatic feature selection algorithm Recursive Feature Elimination (RFE) and different classifiers. A stratified split separated the train/test (80%) and validation (20%) sets. Results: Radiomic features derived from T2WI/ADC are associated with GS in patients with PCa. The best model found was multivariate, including image (T2WI/ADC) and clinical (PV and PSA-D) information. The validation area under the curve (AUC) was 0.80 for differentiating csPCa from non-csPCa, exhibiting better performance than PI-RADS (AUC: 0.71) and PSA-D (AUC: 0.78). Conclusion: Our multivariate ML model outperforms PI-RADS v2.1 and established clinical indicators like PSA-D in classifying csPCa accurately. This underscores MRI-derived radiomics' (T2WI/ADC) potential as a robust biomarker for assessing PCa aggressiveness in Hispanic patients.
- ItemOncological benefit versus cardiovascular risk in breast cancer patients treated with modern radiotherapy(2022) Acevedo, Francisco; Ip, Teresa; Orellana, María; Martínez, Gonzalo; Gabrielli, Luigi; Andia, Marcelo; Besa, Cecilia; Pinto, Mauricio P.; Sánchez, Cesar; Merino, TomasRadiotherapy (RT) is an essential part of breast cancer (BC) treatments. Unfortunately, heart exposure to radiation can also impair the long-term survival of patients. Our study aimed to quantify the oncological benefit and the cardiovascular (CV) risk associated with modern RT in a real-world cohort of BC patients. Our descriptive study enrolled BC patients who received adjuvant RT. Ten-year overall survival (OS) was estimated using Predict® version 2.1 (National Health Service, London, UK). The basal risk of CV events was estimated using the American Heart Association (ACC/AHA) CV score. Treatment volumes and mean cardiac doses were obtained from RT treatment plan records. The increased risk of CV events due to RT was estimated using a model proposed by Darby. The risk of acute myocardial infarction or stroke mortality was estimated using HeartScore® (European Society of Cardiology, Brussels, Belgium). A total of 256 BC patients were included in the study. The average age of patients was 57 years old (range: 25–91); 49.6% had left BC. The mean cardiac dose was 166 cGy (interquartile range (IQR) 94–273); the estimated hazard ratio (HR) for CV disease was HR 1.12 (confidence interval (CI) 1.04–1.24). The estimated baseline 10-year CV risk was 5.6% (0.2 to 51.2); CV risk increased by 0.9% (range 0.02–35.47%) after RT. The absolute risk of 10-year mortality from CV disease was 2.5% (0.1–9); RT was associated with an estimated 4.9% survival benefit (3.73–6.07) against BC death and a 0.23% (0.17–0.29) estimated increase in CV mortality. Modern RT decreased 10-year BC mortality by 4% but increased CV mortality by 0.2% in this cohort. Our findings encourage the implementation of personalized adjuvant RT treatments that balance risks and benefits to improve long-term BC patient survival.
- ItemPortal biliopathy: a multitechnique imaging approach(2012) Besa, Cecilia; Pablo Cruz, Juan; Huete, Alvaro; Cruz, FranciscoPortal biliopathy (PB) is a disorder characterized by biliary ductal and gallbladder wall abnormalities seen in patients with extrahepatic portal vein obstruction. These abnormalities consist mainly of bile duct compression and tethering, stenoses, fibrotic strictures and dilatation of both extrahepatic and intrahepatic bile ducts, as well as gallbladder varices. In this pictorial essay, we describe the imaging findings of PB, which allow differentiation of this entity from other diseases that may have similar imaging findings including cholangiocarcinoma, extrinsic compression of the bile duct caused by metastatic adenopathy or sclerosing cholangitis.
- ItemThe Spectrum from Overt Primary Aldosteronism to Mild Dysregulated Aldosterone Production in Incidentally Discovered Adrenocortical Adenomas(2024) Uslar Nawrath, Thomas Hermann; Olmos, Roberto; Burnier, Alberth; Sanfuentes, Benjamín; Böhm, Pauline; Orellana, Maria Paz; Guarda, Francisco J.; Huete, Alvaro; Mertens, Nicolás; Besa, Cecilia; Andia, Marcelo E.; Majerson, Alejandro; Cartes, Jaime; Fardella, Carlos; Allende, Fidel; Solari, Sandra; Vaidya, Anand; Baudrand Biggs, RenéBackground Incidental adrenocortical adenomas (IA) are common. Current guidelines suggest screening for primary aldosteronism (PA) only in cases of hypertension or hypokalemia. This study aimed to evaluate the spectrum from overt PA to mild dysregulated aldosterone production with a sensitive protocol irrespective of blood pressure (BP) and potassium in patients with IA.Methods 254 consecutive patients (excluding hypercortisolism) were evaluated. The spectrum of PA was defined as a suppressed renin plus the following criteria: 1)Overt PA: aldosterone-to-renin-ratio (ARR) >30 ng/dL-to-ng/mL/hr, plasma aldosterone concentration (PAC) >15ng/dL, and/or 24h urinary aldosterone >10 ug/24h; 2)Moderate PA: ARR 20-30 ng/dL-to-ng/mL/hr, PAC 10-15 ng/dL; 3)Mild dysregulated aldosterone production: ARR <20 ng/dL-to-ng/mL/hr and PAC >5-10 ng/dL.Results 35% (n=89/254) met criteria for PA spectrum, 20% (34/89) were initially normotensive and 94% (84/89) normokalemic. Overt, moderate, and mild groups were 10%, 12%, and 13%. There were trends across groups of clinical severity: systolic BP (153±19, 140±14, 137±14 mmHg, p-trend<0.05), resistant hypertension (50%, 23%, 7% p-trend=<0.001), daily defined dose of antihypertensives (DDD) (3.2±1.6, 1.2±1.5, 0.4±0.6 p-trend=0.001), and lower eGFR (75.5±30.8, 97.8±38.5, 101±25.5, p-trend<0.01). At follow-up (mean 28±15 months), 87% had treatment with MR antagonists or surgery with decreased systolic BP relative to clinical severity, −31.3 ±23, −12.7 ±19, and −11.4 ±19 mmHg, (p-trend<0.001). Similar trends were observed for DDD, with significant increase in renin.Conclusions There is a prevalent spectrum of clinically-relevant PA and dysregulated aldosterone production in IA, irrespective of BP or potassium, usually undetected. Aldosterone-directed treatment improved BP and normalized renin even in milder cases.