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1.
AJR Am J Roentgenol ; 222(1): e2329826, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37877600

RESUMO

BACKGROUND. Adrenal washout CT is not useful for evaluating incidental adrenal masses in patients without known or suspected primary extraadrenal malignancy. OBJECTIVE. The purpose of our study was to evaluate the diagnostic utility of adrenal mass biopsy in patients without known or suspected extraadrenal primary malignancy. METHODS. This retrospective six-center study included 69 patients (mean age, 56 years; 32 men, 37 women) without known or suspected extraadrenal primary malignancy who underwent image-guided core needle biopsy between January 2004 and June 2021 of a mass suspected to be arising from the adrenal gland. Biopsy results were classified as diagnostic or nondiagnostic. For masses resected after biopsy, histopathologic concordance was assessed between diagnoses from biopsy and resection. Masses were classified as benign or malignant by resection or imaging follow-up, and all nondi-agnostic biopsies were classified as false results. RESULTS. The median mass size was 7.4 cm (range, 1.9-19.2 cm). Adrenal mass biopsy had a diagnostic yield of 64% (44/69; 95% CI, 51-75%). After biopsy, 25 masses were resected, and 44 had imaging follow-up. Of the masses that were resected after diagnostic biopsy, diagnosis was concordant between biopsy and resection in 100% (12/12). Of the 13 masses that were resected after nondiagnostic biopsy, the diagnosis from re-section was benign in eight masses and malignant in five masses. The 44 masses with imaging follow-up included one mass with diagnostic biopsy yielding benign adenoma and two masses with nondiagnostic biopsy results that were classified as malignant by imaging follow-up. Biopsy had overall sensitivity and specificity for malignancy of 73% (22/30) and 54% (21/39), respectively; diagnostic biopsies had sensitivity and specificity for malignancy of 96% (22/23) and 100% (21/21), respectively. Among nine nondi-agnostic biopsies reported as adrenocortical neoplasm, six were classified as malignant by the reference standard (resection showing adrenocortical carcinoma in four, resection showing adrenocortical neoplasm of uncertain malignant potential in one, imaging follow-up consistent with malignancy in one). CONCLUSION. Adrenal mass biopsy had low diagnostic yield, with low sensitivity and low specificity for malignancy. A biopsy result of adrenocortical neoplasm did not reliably differentiate benign and malignant adrenal masses. CLINICAL IMPACT. Biopsy appears to have limited utility for the evaluation of incidental adrenal masses in patients without primary extraadrenal malignancy.


Assuntos
Neoplasias do Córtex Suprarrenal , Neoplasias das Glândulas Suprarrenais , Masculino , Humanos , Feminino , Pessoa de Meia-Idade , Neoplasias das Glândulas Suprarrenais/patologia , Estudos Retrospectivos , Glândulas Suprarrenais , Neoplasias do Córtex Suprarrenal/patologia , Sensibilidade e Especificidade , Biópsia Guiada por Imagem/métodos
2.
Can Assoc Radiol J ; : 8465371241255895, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38832645

RESUMO

Purpose: To evaluate the accuracy of a Bidirectional Encoder Representations for Transformers (BERT) Natural Language Processing (NLP) model for automating triage and protocol selection of cross-sectional image requisitions. Methods: A retrospective study was completed using 222 392 CT and MRI studies from a single Canadian university hospital database (January 2018-September 2022). Three hundred unique protocols (116 CT and 184 MRI) were included. A BERT model was trained, validated, and tested using an 80%-10%-10% stratified split. Naive Bayes (NB) and Support Vector Machine (SVM) machine learning models were used as comparators. Models were assessed using F1 score, precision, recall, and area under the receiver operating characteristic curve (AUROC). The BERT model was also assessed for multi-class protocol suggestion and subgroups based on referral location, modality, and imaging section. Results: BERT was superior to SVM for protocol selection (F1 score: BERT-0.901 vs SVM-0.881). However, was not significantly different from SVM for triage prediction (F1 score: BERT-0.844 vs SVM-0.845). Both models outperformed NB for protocol and triage. BERT had superior performance on minority classes compared to SVM and NB. For multiclass prediction, BERT accuracy was up to 0.991 for top-5 protocol suggestion, and 0.981 for top-2 triage suggestion. Emergency department patients had the highest F1 scores for both protocol (0.957) and triage (0.986), compared to inpatients and outpatients. Conclusion: The BERT NLP model demonstrated strong performance in automating the triage and protocol selection of radiology studies, showing potential to enhance radiologist workflows. These findings suggest the feasibility of using advanced NLP models to streamline radiology operations.

3.
Can Assoc Radiol J ; : 8465371241243271, 2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38581354

RESUMO

While hydrocelectomy is the gold-standard for treating hydroceles, it poses an increased risk to patients and a greater burden to the healthcare system. Sclerotherapy is an alternative treatment for hydroceles that involves injecting a sclerosant into the hydrocele under ultrasound guidance. This literature review aimed to assess the types of sclerosants used and how sclerotherapy compares to hydrocelectomy. A literature search was conducted of MEDLINE and EMBASE using the terms "sclerotherapy" and "hydrocelectomy," which yielded 1058 studies, of which 29 met the inclusion criteria. Only studies published after 2000 were included to ensure the most recent information was reviewed. The results showed hydrocele sclerotherapy is done using a variety of sclerosants. The most used agents are polidocanol, phenol, and STS. Of these, phenol had the highest clinical success rate of 96.5%. There was evidence for the use of atypical agents, such as tetracycline antibiotics, which yielded cure rates up to 93%, and alcohol, which was found to be especially useful for treating multiseptated hydroceles. The results comparing sclerotherapy to hydrocelectomy indicated hydrocelectomy to be a more effective method in completely curing hydroceles. However, this came at the cost of more complications. Additionally, sclerotherapy was found to be more advantageous for secondary outcomes, such as healthcare costs and burden to patients. In conclusion, this review shows that while hydrocelectomy is more effective, sclerotherapy is a valuable alternative for treating hydroceles. Due to the lack of standardization among studies, a definitive conclusion cannot be made regarding which sclerosant is best to use.

4.
Can Assoc Radiol J ; 74(1): 93-99, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35998898

RESUMO

Objective: Poor quality imaging requisitions lower report quality and impede good patient care. Manual control of such requisitions is time consuming and can be a source of friction with referring physicians. The purpose of this study was to determine if poor quality requisitions could be identified automatically using machine learning and natural language processing techniques in order to allow for more efficient workflow. Methods: Exam indications from 50 000 musculoskeletal radiograph requisitions were manually classified, reviewed and deemed 'appropriate' or 'inappropriate' by two staff radiologists based on ACR appropriateness criteria. The requisitions were divided into training and test groups (80/20 split). The training set was pre-processed, converted to a bag-of-words model and used to train a Multinomial Naïve Bayes classifier which was then applied to the test set. Results: Out of 50 000 requisitions, 12 253 (24.5%) were deemed to contain an inappropriate indication. A Naive Bayes model correctly classified requisitions with an accuracy of 98%. In the test set, 107 of 7561 (1.4%) appropriate requisitions were incorrectly flagged and 92 of 2439 (3.8%) inappropriate requisitions were not flagged. Conclusions: Accurate automated identification of inappropriate indications on musculoskeletal requisitions is feasible using machine learning and natural language processing.


Assuntos
Aprendizado de Máquina , Humanos , Teorema de Bayes , Radiografia
5.
Can Assoc Radiol J ; 72(4): 883-889, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32673070

RESUMO

PURPOSE: To compare the wait times, safety, and diagnostic adequacy of computed tomography (CT)-guided percutaneous lung biopsies with ultrasound (US) guidance for subpleural lung and pleural lesions. METHODS: Consecutive CT- and US-guided biopsies performed at our institution between January 2018 and January 2019 were retrospectively reviewed. Biopsy wait times, lesion size, degree of pleural contact, procedure duration, number of needle passes, complications, and pathologic diagnosis were recorded and compared. RESULTS: A total of 158 biopsies of subpleural or pleural-based lesions were reviewed. Forty-three cases utilized US guidance, while 115 cases used CT, 41 with conventional CT (CCT), and 74 with cone-beam CT guidance (CBCT). Overall, the mean lesion maximum axial diameter and length of pleural contact for US-guided biopsies was greater than for CT (4.8 ± 2.6 cm vs 3.2 ± 1.9 cm and 4.0 ± 2.5 cm vs 2.6 ± 1.7 cm, respectively, P < .001). Wait times for US-guided biopsies were significantly shorter than CCT by 10.9 days on average while being equivalent to CBCT. Procedure time was shorter for lesions localized with US than CT (29.5 ± 16.4 minutes vs 37.6 ± 19.5 minutes, P = .007) despite CT using less needle passes per lesion (3.5 ± 1.1 vs 3.1 ± 0.8, P = .034). Sample adequacy was equivalent for both modalities (88% for US and 92% for CT). The frequency of pneumothoraces was similar between US (12%) and CT (15%). CONCLUSION: Ultrasound and CT guidance have similar safety and diagnostic adequacy for subpleural lung and pleural biopsies. Ultrasound guidance has shorter wait and procedure times.


Assuntos
Pulmão/diagnóstico por imagem , Pulmão/patologia , Segurança do Paciente/estatística & dados numéricos , Radiografia Intervencionista/métodos , Tomografia Computadorizada por Raios X/métodos , Ultrassonografia de Intervenção/métodos , Listas de Espera , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Biópsia Guiada por Imagem/efeitos adversos , Biópsia Guiada por Imagem/métodos , Masculino , Pessoa de Meia-Idade , Pleura/diagnóstico por imagem , Pleura/patologia , Reprodutibilidade dos Testes , Fatores de Tempo
6.
J Hepatol ; 70(5): 866-873, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30615906

RESUMO

BACKGROUND & AIMS: Radiofrequency ablation (RFA) is an effective treatment for single hepatocellular carcinoma (HCC) ≤3 cm. Disease recurrence is common, and in some patients will occur outside transplant criteria. We aimed to assess the incidence and risk factors for recurrence beyond Milan criteria in potentially transplantable patients treated with RFA as first-line therapy. METHODS: We performed a retrospective cohort study of potentially transplantable patients with new diagnoses of unifocal HCC ≤3 cm that underwent RFA as first-line therapy between 2000-2015. We defined potentially transplantable patients as those aged <70 years without any comorbidities that would preclude transplant surgery. Incidence of recurrence beyond Milan criteria was compared across 2 groups according to HCC diameter at the time of ablation: (HCC ≤2 cm vs. HCC >2 cm). Competing risks Cox regression was used to identify predictors of recurrence beyond Milan criteria. RESULTS: We included 301 patients (167 HCC ≤2 cm and 134 HCC >2 cm). Recurrence beyond Milan criteria occurred in 36 (21.6%) and 47 (35.1%) patients in the HCC ≤2 cm and the HCC >2 cm groups, respectively (p = 0.01). The 1-, 3- and 5-year actuarial survival rates after RFA were 98.2%, 86.2% and 79.0% in the HCC ≤2 cm group vs. 93.3%, 77.6% and 70.9% in the HCC >2 cm group (p = 0.01). Tumor size >2 cm (hazard ratio 1.94; 95%CI 1.25-3.02) and alpha-fetoprotein levels at the time of ablation (100-1,000 ng/ml: hazard ratio 2.05; 95%CI 1.10-3.83) were found to be predictors of post-RFA recurrence outside Milan criteria. CONCLUSION: RFA for single HCC ≤3 cm provides excellent short- to medium-term survival. However, we identified patients at higher risk of recurrence beyond Milan criteria. For these patients, liver transplantation should be considered immediately after the first HCC recurrence following RFA. LAY SUMMARY: Radiofrequency ablation and liver transplantation are treatment options for early stages of hepatocellular carcinoma (HCC). After ablation some patients will experience recurrence or metastatic spread of the initial tumor or may develop new tumors within the liver. Despite close follow-up, these recurrences can progress rapidly and exceed transplant criteria, preventing the patient from receiving a transplant. We identified that patients with HCC >2 cm and higher serum alpha-fetoprotein are at greater risk of recurrence beyond the transplant criteria. These data suggest that liver transplantation should be considered immediately after the first HCC recurrence for these patients.


Assuntos
Carcinoma Hepatocelular/cirurgia , Ablação por Cateter/métodos , Neoplasias Hepáticas/cirurgia , Transplante de Fígado , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/patologia , Feminino , Humanos , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/epidemiologia , Estudos Retrospectivos , alfa-Fetoproteínas/análise
7.
Vascular ; 27(2): 168-174, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30396328

RESUMO

PURPOSE: Proximal type 1A endoleaks on completion intra-operative angiography are not infrequently seen following endovascular abdominal aneurysm repair (EVAR). The natural course of these leaks is not well established. We sought to determine the rate of spontaneous resolution and a conservative treatment approach to these endoleaks. METHODS: All cases involving endovascular repairs of infra-renal abdominal aortic aneurysms resulting in proximal type 1A endoleak on final intra-operative completion angiography were retrospectively reviewed from 1 April 2010 and 30 March 2015. Demographic, pre and post-procedural imaging, and clinical outcomes were reviewed. Summarizing descriptive statistics are reported. RESULTS: Of the 337 patients who underwent an EVAR, 24 patients (7.1%) had a proximal type 1A endoleak on final intra-operative angiography. Twenty-two of 24 patients (92%) with proximal type 1A endoleaks had spontaneous resolution on follow-up imaging without any intervention, while two (8%) patients had a persistent endoleak. One of these patients required intervention. The median follow-up for patients with resolved endoleaks was 2.5 years vs. 4 and 6 years, respectively, for patients that did not resolve spontaneously. CONCLUSION: A conservative approach may be used in the management of patients with proximal type 1A endoleaks on completion angiography once maximum proximal seal was achieved intra-operatively as the vast majority of these leaks spontaneously seal.


Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Aortografia , Implante de Prótese Vascular/efeitos adversos , Implante de Prótese Vascular/instrumentação , Prótese Vascular , Tratamento Conservador , Endoleak/diagnóstico por imagem , Endoleak/terapia , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/instrumentação , Stents , Idoso , Idoso de 80 Anos ou mais , Angiografia Digital , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aortografia/métodos , Angiografia por Tomografia Computadorizada , Endoleak/etiologia , Feminino , Humanos , Masculino , Valor Preditivo dos Testes , Desenho de Prótese , Estudos Retrospectivos , Fatores de Risco , Resultado do Tratamento
8.
J Vasc Interv Radiol ; 28(3): 325-333, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28073607

RESUMO

PURPOSE: To compare survival outcomes of small solitary hepatocellular carcinomas (HCCs) treated with thermal ablation vs resection in the Surveillance, Epidemiology, and End Results (SEER) cohort. MATERIALS AND METHODS: SEER data (November 2014 submission) were searched for histologic diagnoses of HCC and stage T1 disease (≤ 5-cm solitary tumor without vascular invasion). Comparison was made between thermal ablation and resection as the primary treatment. Overall and disease-specific survival were compared by log-rank tests (stratified for presence of fibrosis) and Cox regression (with tumor size and presence of fibrosis covariates). RESULTS: Of 264 patients with ≤ 2-cm HCCs, 185 underwent thermal ablation and 79 underwent resection. Patients undergoing ablation had higher Ishak scores (P = .0002). There was no difference in survival (observed P = .698, disease-specific P = .446). Of 544 patients with 2.1-4-cm HCCs, 335 underwent thermal ablation and 209 underwent resection. Patients undergoing ablation were more likely to have higher Ishak scores (P < .001), but had slightly smaller tumors (2.9 vs 3.1 cm; P < .001). There was no difference in survival (observed P = .174, disease-specific P = .609). Of 112 patients with 4.1-5-cm HCCs, 46 underwent thermal ablation and 66 underwent resection. Patients undergoing ablation had higher Ishak scores (P = .0002). Surgical resection was associated with improved survival (observed P = .009, disease-specific P = .046). CONCLUSIONS: There was no difference in overall or disease-specific survival between surgical resection and thermal ablation for T1 HCCs ≤ 4 cm after adjusting for the presence of histologic fibrosis and tumor size in the SEER cohort. Significant benefit was observed with surgery for tumors measuring 4.1-5 cm.


Assuntos
Técnicas de Ablação , Carcinoma Hepatocelular/cirurgia , Hepatectomia , Neoplasias Hepáticas/cirurgia , Técnicas de Ablação/efeitos adversos , Técnicas de Ablação/mortalidade , Idoso , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/patologia , Intervalo Livre de Doença , Feminino , Hepatectomia/efeitos adversos , Hepatectomia/mortalidade , Humanos , Estimativa de Kaplan-Meier , Cirrose Hepática/patologia , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores de Risco , Programa de SEER , Fatores de Tempo , Resultado do Tratamento , Carga Tumoral , Estados Unidos
9.
J Vasc Interv Radiol ; 28(1): 16-22, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27884686

RESUMO

PURPOSE: To assess efficacy of two different techniques of lidocaine injection in the uterine arteries to reduce pain following uterine artery embolization (UAE) for leiomyomas. MATERIALS AND METHODS: This prospective randomized single-blinded study was performed with 60 patients enrolled between November 2014 and December 2015 equally randomized to 3 arms. Group A received 10 mL lidocaine 1% (100 mg) mixed with polyvinyl alcohol particles (355-500 µm). Group B received the same dose of lidocaine injected after embolization. Group C was a control group. Pain was assessed on a 100-point visual analog scale at 4, 7, and 24 hours after the procedure. Narcotic agent dose to 24 hours was recorded. Outcomes were examined by analysis of variance and pairwise comparison. Leiomyoma infarction was assessed with magnetic resonance imaging 3 months after the procedure. RESULTS: Technical success rate of UAE was 100%. Mean pain score at 4 hours was significantly lower in the lidocaine groups (group A, 28.6; group B, 35.8) compared with the control group (59.4; P = .001). Pain scores at 7 and 24 hours were not statistically different among the 3 arms. The mean in-hospital narcotic agent dose was significantly lower in both lidocaine groups than in the control group (group A, 8.5 mg [P = .002]; group B, 11.1 mg [P = .03]; group C, 17.4 mg). There were no adverse events related to the use of lidocaine. The number of patients with complete infarction of leiomyomas at 3 months was significantly lower in group A at 38.9% (group B, 77.8%; group C, 75%; P = .0451). CONCLUSIONS: Lidocaine injected in the uterine arteries reduced postprocedural pain and narcotic agent dose after UAE. There were more cases of incomplete necrosis when lidocaine was mixed with the particles.


Assuntos
Anestésicos Locais/administração & dosagem , Leiomioma/terapia , Lidocaína/administração & dosagem , Dor/prevenção & controle , Álcool de Polivinil/efeitos adversos , Embolização da Artéria Uterina/efeitos adversos , Neoplasias Uterinas/terapia , Adulto , Analgésicos não Narcóticos/administração & dosagem , Analgésicos Opioides/administração & dosagem , Análise de Variância , Anestésicos Locais/efeitos adversos , Feminino , Humanos , Injeções Intra-Arteriais , Leiomioma/diagnóstico por imagem , Lidocaína/efeitos adversos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Ontário , Dor/diagnóstico , Dor/etiologia , Medição da Dor , Álcool de Polivinil/administração & dosagem , Estudos Prospectivos , Método Simples-Cego , Fatores de Tempo , Resultado do Tratamento , Neoplasias Uterinas/diagnóstico por imagem
10.
J Vasc Interv Radiol ; 27(12): 1897-1905.e1, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27435682

RESUMO

PURPOSE: To report outcomes after portal vein embolization (PVE) and right hepatectomy in patients receiving embolization with N-butyl cyanoacrylate (NBCA) glue + central AMPLATZER Vascular Plug (AVP; glue group) or polyvinyl alcohol (PVA) particles ± coils (PVA group). MATERIALS AND METHODS: Between March 2008 and August 2013, all patients having PVE with NBCA + AVP or PVA ± coils before right hepatectomy were retrospectively reviewed; 85 patients underwent PVE with NBCA + AVP (n = 45) or PVA ± coils (n = 40). The groups were compared using Mann-Whitney U and χ2 tests. RESULTS: Technical success of embolization was 100%. Degree of hypertrophy (16.2% ± 7.8 vs 12.3% ± 7.62, P = .009) and kinetic growth rate (3.5%/wk ± 2.0 vs 2.6%/wk ± 1.9, P = .016) were greater in the glue group versus the PVA group. Contrast volume (66.1 mL ± 44.8 vs 189.87 mL ± 62.6, P < .001) and fluoroscopy time (11.2 min ± 7.8 vs 23.49 min ± 11.7, P < .001) were significantly less during the PVE procedure in the glue group. Surgical outcomes were comparable between groups, including the number of patients unable to go onto surgery (P = 1.0), surgical complications (P = .30), length of hospital stay (P = .68), and intensive care unit admissions (P = .71). There was 1 major complication (hepatic abscess) in each group after PVE. CONCLUSIONS: PVE performed with NBCA + AVP compared with PVA ± coils resulted in greater degree of hypertrophy of the future liver remnant, less fluoroscopic time and contrast volume, and similar complication rates.


Assuntos
Proliferação de Células , Embolização Terapêutica/métodos , Embucrilato/administração & dosagem , Hepatectomia/métodos , Neoplasias Hepáticas/cirurgia , Regeneração Hepática , Álcool de Polivinil/administração & dosagem , Idoso , Distribuição de Qui-Quadrado , Meios de Contraste/administração & dosagem , Embolização Terapêutica/efeitos adversos , Embucrilato/efeitos adversos , Feminino , Fluoroscopia , Hepatectomia/efeitos adversos , Humanos , Hipertrofia , Tempo de Internação , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/fisiopatologia , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Flebografia/métodos , Álcool de Polivinil/efeitos adversos , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
11.
J Am Chem Soc ; 137(31): 9894-911, 2015 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-26200219

RESUMO

We report the transfer-dehydrogenation of gas-phase alkanes catalyzed by solid-phase, molecular, pincer-ligated iridium catalysts, using ethylene or propene as hydrogen acceptor. Iridium complexes of sterically unhindered pincer ligands such as (iPr4)PCP, in the solid phase, are found to give extremely high rates and turnover numbers for n-alkane dehydrogenation, and yields of terminal dehydrogenation product (α-olefin) that are much higher than those previously reported for solution-phase experiments. These results are explained by mechanistic studies and DFT calculations which jointly lead to the conclusion that olefin isomerization, which limits yields of α-olefin from pincer-Ir catalyzed alkane dehydrogenation, proceeds via two mechanistically distinct pathways in the case of ((iPr4)PCP)Ir. The more conventional pathway involves 2,1-insertion of the α-olefin into an Ir-H bond of ((iPr4)PCP)IrH2, followed by 3,2-ß-H elimination. The use of ethylene as hydrogen acceptor, or high pressures of propene, precludes this pathway by rapid hydrogenation of these small olefins by the dihydride. The second isomerization pathway proceeds via α-olefin C-H addition to (pincer)Ir to give an allyl intermediate as was previously reported for ((tBu4)PCP)Ir. The improved understanding of the factors controlling rates and selectivity has led to solution-phase systems that afford improved yields of α-olefin, and provides a framework required for the future development of more active and selective catalytic systems.

12.
J Am Chem Soc ; 135(39): 14644-58, 2013 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-23927450

RESUMO

Designing oxidation catalysts based on CH activation with reduced, low oxidation state species is a seeming dilemma given the proclivity for catalyst deactivation by overoxidation. This dilemma has been recognized in the Shilov system where reduced Pt(II) is used to catalyze methane functionalization. Thus, it is generally accepted that key to replacing Pt(IV) in that system with more practical oxidants is ensuring that the oxidant does not over-oxidize the reduced Pt(II) species. The "Periana-Catalytica" system, which utilizes (bpym)Pt(II)Cl2 in concentrated sulfuric acid solvent at 200 °C, is a highly stable catalyst for the selective, high yield oxy-functionalization of methane. In lieu of the over-oxidation dilemma, the high stability and observed rapid oxidation of (bpym)Pt(II)Cl2 to Pt(IV) in the absence of methane would seem to contradict the originally proposed mechanism involving CH activation by a reduced Pt(II) species. Mechanistic studies show that the originally proposed mechanism is incomplete and that while CH activation does proceed with Pt(II) there is a solution to the over-oxidation dilemma. Importantly, contrary to the accepted view to minimize Pt(II) overoxidation, these studies also show that increasing that rate could increase the rate of catalysis and catalyst stability. The mechanistic basis for this counterintuitive prediction could help to guide the design of new catalysts for alkane oxidation that operate by CH activation.

13.
Plants (Basel) ; 12(5)2023 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-36904057

RESUMO

In this work, a new material for in vitro plant rooting based on highly dispersed polyacrylamide hydrogel (PAAG) enriched with amber powder was synthesized and investigated. PAAG was synthesized by homophase radical polymerization with ground amber addition. Fourier transform infrared spectroscopy (FTIR) and rheological studies were used to characterize the materials. They showed that the synthesized hydrogels have physicochemical and rheological parameters similar to those of the standard agar media. The acute toxicity of PAAG-amber was estimated based on the influence of washing water on the viability of plant seeds (pea and chickpea) and Daphnia magna. It proved its biosafety after four washes. The impact on plant rooting was studied using the propagation of Cannabis sativa on synthesized PAAG-amber and compared with agar. The developed substrate stimulated the rooting of the plants to more than 98% in comparison to standard agar medium (95%). Additionally, the use of PAAG-amber hydrogel markedly enhanced metric indicators of seedlings: root length increased by 28%, stem length-by 26.7%, root weight-by 167%, stem weight-by 67%, root and stem length-by 27%, root and stem weight-by 50%. This means that the developed hydrogel significantly accelerates reproduction and allows obtaining a larger amount of plant material within a shorter period of time than the standard agar substrate.

14.
Radiology ; 258(3): 776-84, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21193598

RESUMO

PURPOSE: To determine the prognostic importance of pleural effusions on preoperative computed tomographic (CT) images in patients with advanced epithelial ovarian cancer. MATERIALS AND METHODS: The institutional review board waived informed consent for this HIPAA-compliant study of 203 patients with International Federation of Obstetrics and Gynecology stage III (n = 172) or IV (n = 31) epithelial ovarian cancer who underwent CT before primary cytoreductive surgery between 1997 and 2004 (mean age, 61 years; range, 37-96 years). Two radiologists retrospectively evaluated chest and/or abdominal CT images for pleural malignancy and the presence, size, and laterality of pleural effusions. To evaluate survival, Kaplan-Meier methods were used, with log-rank P values for comparisons. Multivariate analyses were conducted by using Cox proportional hazards regression. κ Statistics were calculated for interreader agreement. RESULTS: Median survival was 50 months (95% confidence interval [CI]: 45, 55 months) for patients with stage III disease and 41 months (95% CI: 27, 58 months) for patients with stage IV disease. Readers 1 and 2 found pleural effusions in 40 and 41 stage III and 20 and 21 stage IV patients, respectively. At multivariate analysis, after controlling for stage, age at surgery, preoperative serum CA-125 level, debulking status, and ascites, moderate-to-large pleural effusion on CT images was significantly associated with worse overall survival (reader 1: hazard ratio = 2.27 [95% CI: 1.31, 3.92], P < .01; reader 2: hazard ratio = 2.25 [95% CI: 1.26, 4.01], P = .02). Preoperative CA-125 level, debulking status, and ascites were also significant survival predictors (P ≤ .03 for all for both readers). Readers agreed substantially in distinguishing small from moderate-to-large effusions (κ = 0.764). CONCLUSION: Moderate-to-large pleural effusion on preoperative CT images in patients with stage III or IV epithelial ovarian cancer was independently associated with poorer overall survival after controlling for age, preoperative CA-125 level, surgical stage, ascites, and cytoreductive status.


Assuntos
Neoplasias Ovarianas/patologia , Derrame Pleural/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/análise , Antígeno Ca-125/análise , Feminino , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Ovarianas/cirurgia , Derrame Pleural/etiologia , Prognóstico , Modelos de Riscos Proporcionais , Taxa de Sobrevida
15.
Radiology ; 257(1): 125-34, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20697116

RESUMO

PURPOSE: To compare accuracy and interobserver variability in the detection and localization of recurrent ovarian cancer with contrast material-enhanced (CE) computed tomography (CT) and positron emission tomography (PET)/CT and determine whether imaging findings can be used to predict survival. MATERIALS AND METHODS: Waiving informed consent, the institutional review board approved this HIPAA-compliant, retrospective study of 35 women (median age, 54.4 years) with histopathologically proven recurrent ovarian carcinoma who underwent CE CT and PET/CT before exploratory surgery. All CE CT and PET/CT scans were independently analyzed. Tumor presence, number of lesions, and the size and maximum standardized uptake value (SUV(max)) of the largest lesion were recorded for patient and region. Surgical histopathologic findings constituted the reference standard. Areas under the receiver operating characteristic curves (AUCs), κ statistics, and hazard ratios were calculated. RESULTS: Readers' AUCs in detection of recurrence for region were 0.85 (95% confidence interval [CI]: 0.81, 0.90) and 0.78 (95% CI: 0.72, 0.83) for CE CT and 0.84 (95% CI: 0.79, 0.89) and 0.74 (95% CI: 0.67, 0.81) for PET/CT (P = .76); 12 patients died. At PET/CT, size, number, and SUV(max) of peritoneal deposits were significantly associated with poor survival for readers 1 and 2 (P ≤ .01and ≤ .05, respectively), as were long- and short-axis diameters, number, and SUV(max) of distant lymph nodes for reader 1 (P ≤ .001). With CE CT, size (reader 1) and number (readers 1 and 3) of peritoneal deposits were significantly associated with poor survival (P ≤ .01), as were long- and short-axis diameters and number of distant lymph nodes for reader 1 (P ≤ .01). Interobserver agreement ranged from fair (patient, κ = 0.30) to moderate (region, κ = 0.55) for CE CT and fair (patient, κ = 0.24) to substantial (region, κ = 0.63) for PET/CT. CONCLUSION: Preliminary data suggest that CE CT and PET/CT may have similar accuracy in detection of recurrent ovarian cancer. Tumor size, number, and SUV(max) may have potential as prognostic biomarkers for patients with recurrent ovarian cancer.


Assuntos
Recidiva Local de Neoplasia/diagnóstico por imagem , Neoplasias Ovarianas/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada por Raios X/métodos , Área Sob a Curva , Meios de Contraste , Estudos Transversais , Feminino , Humanos , Metástase Linfática , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Variações Dependentes do Observador , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/cirurgia , Valor Preditivo dos Testes , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Taxa de Sobrevida
16.
Int J Gynecol Cancer ; 20(6): 979-84, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20683405

RESUMO

INTRODUCTION: It has been hypothesized that the supradiaphragmatic lymph nodes serve as the principal nodes for lymphatic drainage of the entire peritoneal cavity. The purpose of this study was to determine the prognostic significance of enlarged supradiaphragmatic nodes noted on preoperative computed tomographic (CT) scan in patients undergoing primary cytoreduction for advanced epithelial ovarian cancer (EOC). METHODS: We performed a retrospective chart review of all patients with stage III and IV EOC according to the International Federation of Gynecology and Obstetrics who had preoperative CT scans, including the supradiaphragmatic region, and had undergone primary cytoreductive surgery at our institution between January 1997 and June 2004. Scans were retrospectively reviewed by a radiologist. We defined supradiaphragmatic adenopathy as nodes measuring greater than 5 mm on the largest of 2 perpendicular measurements on the CT scan. The Fisher exact test was used to compare proportions. Kaplan-Meier curves and log-rank tests were used for the survival analyses. RESULTS: A total of 212 evaluable patients were identified. All underwent attempted primary cytoreduction followed by systemic chemotherapy. None had any supradiaphragmatic nodes removed at primary cytoreduction. With a median follow-up time of 52 months, median overall survival for the entire cohort was 48 months. Of 212 patients, 92 (43%) had supradiaphragmatic adenopathy. Median survival was 50 months for patients without adenopathy and 45 months for patients with adenopathy (P = 0.09). Of the 212 patients, 155 (73%) underwent optimal cytoreduction. In these patients, median survival was 55 months for the 91 without adenopathy and 50 months for the 64 patients with supradiaphragmatic adenopathy (P = 0.09). CONCLUSIONS: We observed a trend toward worse survival in patients with enlarged supradiaphragmatic nodes. The prognostic impact of supradiaphragmatic adenopathy remains uncertain and deserves further study.


Assuntos
Carcinoma/mortalidade , Carcinoma/secundário , Linfonodos/diagnóstico por imagem , Linfonodos/patologia , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Adulto , Idoso , Carcinoma/tratamento farmacológico , Carcinoma/cirurgia , Quimioterapia Adjuvante , Estudos de Coortes , Diafragma , Feminino , Humanos , Doenças Linfáticas/diagnóstico por imagem , Doenças Linfáticas/patologia , Metástase Linfática , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/cirurgia , Ovariectomia/efeitos adversos , Ovariectomia/métodos , Cuidados Pré-Operatórios/métodos , Prognóstico , Estudos Retrospectivos , Medição de Risco , Análise de Sobrevida , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento
17.
Can Urol Assoc J ; 14(12): 398-403, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32574144

RESUMO

INTRODUCTION: Small renal masses (SRMs), enhancing tumors <4 cm in diameter, are suspicious for renal cell carcinoma (RCC). The incidence of SRMs have risen with the increased quality and frequency of imaging. Partial nephrectomy is widely accepted as a nephron-sparing approach for the management of clinically localized RCC, with a greater than 90% disease-specific survival for stage T1a. Radiofrequency ablation (RFA) has been emerging as an alternative management strategy, with evidence suggesting RFA as a safe alternative for SRMs. We aimed to evaluate the time to recurrence and recurrence rates of SRMs treated with RFA at our institution. METHODS: A retrospective review between October 2011 and May 2019 identified 141 patients with a single SRM treated with RFA at Hamilton Health Sciences and St. Joseph's Healthcare Hamilton. Patients with familial syndromes and distant metastases were excluded. Repeat RFAs of the ipsilateral kidney for incomplete ablation were not considered a new procedure. The primary variable measured was time from initial ablation to recurrence. A Cox proportional hazard regression model was used to identify possible prognostic variables for tumor recurrence defined a priori, including age, gender, mass size, RENAL nephrometry, and PADUA scores. RESULTS: The overall average age of our patients was 69.0±11.1 years, with 71.6% being male. Average tumor size was 2.6±0.8 cm. There were 22/154 total recurrences (15.6%) post-RFA. Median followup time was 67 (18-161) months. Those with new recurrences had median time to recurrence of 15 months and no recurrence beyond 53 months. Thirteen of 141 patients had residual disease (9.2%) and were identified within the first eight months post-RFA. The only prognostic variable identified as a predictor of residual disease was tumor size (hazard ratio 2.265; p<0.001). CONCLUSIONS: This study shows the risk of a new recurrence following RFA for SRMs is 6.4%. Most recurrences (9.2%) were a result of residual tumor at the ablation site identified within the first eight months post-RFA. No recurrences were identified beyond 53 months, with a total median followup time of 67 months. Tumor size alone, without need for complex scoring systems, may serve as a predictor of incomplete ablation following RFA and could be used to assist in shared decision-making on management strategies.

18.
Vasc Endovascular Surg ; 53(5): 395-400, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31018828

RESUMO

PURPOSE: To evaluate the feasibility and safety of a novel balloon-expandable, heparin-bonded endoprosthesis (Viabahn VBX, W. L. Gore and Associates) when used as a bridging stent graft (BSG) with fenestrated and branched endovascular aneurysm repair (FB-EVAR). FB-EVAR and BSGs increase repair complexity with the potential for endoleak formation, stenosis, thrombosis, and graft migration. The mechanical construction of the Viabahn VBX and its antithrombogenic properties may provide an advantage for FB-EVAR over existing BSGs. The efficacy, safety, and clinical outcomes were assessed. MATERIALS AND METHODS: Research ethics board approved, prospective, single arm cohort, pilot study of patients undergoing FB-EVAR between February 2017 and January 2018. Fenestrated and branched endovascular aneurysm repair was performed per the standard institutional protocol by a team composed of vascular surgeons and interventional radiologists. Viabahn VBX endografts were used for all intended visceral branches as long as appropriately sized devices were available (Under Investigational Testing Authorization from Health Canada). Patient characteristics, procedural details, and technical and clinical outcomes were reviewed and summarized. RESULTS: FB-EVAR was performed in 13 patients (9 male and 4 female) mean age of 74 (range: 61-83) with a total of 41 Viabahn VBXs stents implanted. Mean maximum aneurysm size was 6.7 cm (range: 5.5-9.0 cm) and included 5 juxtarenal abdominal aortic aneurysms and 8 thoracoabdominal; 3 type V, 3 type IV, and 2 type III (Crawford Classification). The Viabahn VBX was successfully deployed in 40 (98%) of 41 of cases. At median follow-up of 223 days (range: 2-462), there was a (40/40) 100% Viabahn VBX patency rate. Seven endoleaks were identified intra- or post procedurally in 6 (46%) of 13 cases, including 1 type IB, 3 type II, 2 type III, and 1 unclassified. Nine complications occurred in 6 patients. CONCLUSION: The Viabahn VBX stent is a safe and effective BSG for FB-EVAR with no early stent thrombosis. Further evaluation is required to determine longer term stent efficacy.


Assuntos
Anticoagulantes/administração & dosagem , Aneurisma da Aorta Abdominal/cirurgia , Aneurisma da Aorta Torácica/cirurgia , Implante de Prótese Vascular/instrumentação , Prótese Vascular , Materiais Revestidos Biocompatíveis , Procedimentos Endovasculares/instrumentação , Heparina/administração & dosagem , Stents , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/efeitos adversos , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aneurisma da Aorta Abdominal/fisiopatologia , Aneurisma da Aorta Torácica/diagnóstico por imagem , Aneurisma da Aorta Torácica/fisiopatologia , Aortografia/métodos , Implante de Prótese Vascular/efeitos adversos , Angiografia por Tomografia Computadorizada , Procedimentos Endovasculares/efeitos adversos , Estudos de Viabilidade , Feminino , Oclusão de Enxerto Vascular/etiologia , Oclusão de Enxerto Vascular/fisiopatologia , Oclusão de Enxerto Vascular/prevenção & controle , Heparina/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Desenho de Prótese , Fatores de Risco , Trombose/etiologia , Trombose/fisiopatologia , Trombose/prevenção & controle , Fatores de Tempo , Resultado do Tratamento , Grau de Desobstrução Vascular/efeitos dos fármacos
19.
Cardiovasc Intervent Radiol ; 41(6): 935-941, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29417268

RESUMO

PURPOSE: To assess the safety and efficacy of percutaneous thermal ablation for the treatment of hepatocellular adenomas. MATERIALS AND METHODS: This is an ethics board-approved, single-arm, retrospective, cohort study of patients with pathologically proven hepatocellular adenomas treated with percutaneous thermal ablation at a tertiary referral center from 1999 to 2016. Demographic, procedural, and outcome data were collected and summarized with appropriate measures of central tendency and dispersion. Complications were graded per the Society of Interventional Radiology reporting guidelines. Determination of primary and secondary technique efficacies was based on post-procedural imaging. RESULTS: Thirty-six patients (4 male, 32 female) with a median age of 35 years had 44 procedures for the treatment of 58 tumors. Twenty-two percent of patients had prior history of adenoma-related hemorrhage. The median tumor size was 2.1 cm (range 0.6-6.0). The majority of treatments were done on an outpatient basis, under moderate sedation, using radiofrequency ablation with ultrasound guidance. The median procedure time was 85 min. There were two immediate post-procedural hemorrhages (4.5% per procedure). During a median follow-up of 1.7 years (95% CI 0.2-8.0), there were no instances of malignant transformation, adenoma-related hemorrhages, or deaths. The primary and secondary technique efficacy rates were 88 and 100%, respectively. CONCLUSION: Thermal ablation for the treatment of hepatocellular adenoma had a primary and secondary efficacy of 88 and 100%, respectively. The major complication rate was 4.5%. The clinical efficacy during a median follow-up of 1.7 year was 100%.


Assuntos
Adenoma de Células Hepáticas/cirurgia , Ablação por Cateter/métodos , Neoplasias Hepáticas/cirurgia , Adulto , Idoso , Estudos de Coortes , Feminino , Humanos , Fígado/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
20.
Cardiovasc Intervent Radiol ; 39(6): 916-9, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26585991

RESUMO

PURPOSE: We describe the design and preliminary characterization of a stent incorporating light-emitting diodes (LEDs) for photodynamic therapy (PDT) of malignant biliary obstruction. METHODS: A prototype was constructed with red (640 nm) LEDs embedded in a 14.5 French polyurethane tube. The device was evaluated for optical power and subjected to physical and electrical tests. PDT-induced reactive oxygen species were imaged in a gel phantom. RESULTS: The stent functioned at a 2.5-cm bend radius and illuminated for 6 months in saline. No stray currents were detected, and it was cool after 30 minutes of operation. Optical power of 5-15 mW is applicable to PDT. Imaging of a reactive oxygen indicator showed LED-stent activation of photosensitizer. CONCLUSIONS: The results motivate biological testing and design optimization.


Assuntos
Neoplasias dos Ductos Biliares/tratamento farmacológico , Colestase/tratamento farmacológico , Fotoquimioterapia/instrumentação , Stents , Colestase/terapia , Desenho de Equipamento , Humanos , Iluminação , Modelos Anatômicos , Fenômenos Ópticos , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes
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