Evaluation of a BERT Natural Language Processing Model for Automating CT and MRI Triage and Protocol Selection.

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.

Sclerotherapy in the Treatment of Hydroceles: A Comprehensive Review of the Efficacy, Types of Sclerosants, and Comparative Outcomes Against Hydrocelectomy.

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.

Adrenal Mass Biopsy in Patients Without Extraadrenal Primary Malignancy: A Multicenter Study.

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.

Polyacrylamide Hydrogel Enriched with Amber for In Vitro Plant Rooting.

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.

Classification of Musculoskeletal Radiograph Requisition Appropriateness Using Machine Learning.

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.

Ultrasound- Versus CT-Guided Subpleural Lung and Pleural Biopsy: An Analysis of Wait Times, Procedure Time, Safety, and Diagnostic Adequacy.

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.

Surveillance post-radiofrequency ablation for small renal masses: Recurrence and followup.

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.

Initial Experience With Viabahn VBX as the Bridging Stent Graft for Branched and Fenestrated Endovascular Aneurysm Repair.

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.

Outcomes of radiofrequency ablation as first-line therapy for hepatocellular carcinoma less than 3 cm in potentially transplantable patients.

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.

Conservative management of type 1A endoleaks at completion angiogram in endovascular repair of infra-renal abdominal aortic aneurysms with current generation stent grafts.

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.

Retrospective Single-Arm Cohort Study of Patients with Hepatocellular Adenomas Treated with Percutaneous Thermal Ablation.

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%.

Thermal Ablation versus Surgical Resection for the Treatment of Stage T1 Hepatocellular Carcinoma in the Surveillance, Epidemiology, and End Results Database Population.

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.

Intraarterial Lidocaine for Pain Control in Uterine Artery Embolization: A Prospective, Randomized Study.

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.

Comparison of Clinical Outcomes following Glue versus Polyvinyl Alcohol Portal Vein Embolization for Hypertrophy of the Future Liver Remnant prior to Right Hepatectomy.

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.

Indwelling Stent Embedded with Light-Emitting Diodes for Photodynamic Therapy of Malignant Biliary Obstruction.

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.

Dehydrogenation of n-Alkanes by Solid-Phase Molecular Pincer-Iridium Catalysts. High Yields of α-Olefin Product.

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.

Idiopathic Intracranial Hypertension: Diagnostic Accuracy of the Transverse Dural Venous Sinus Attenuation on CT Scans.

Idiopathic intracranial hypertension (IIH) is a clinical disorder of unknown etiology. It may exhibit several non-specific imaging findings. We observed that patients with intracranial hypertension demonstrate intracranial venous sinus attenuation with changes in the contour and caliber of the distal transverse sinus. This can be seen on routine non-contrast sagittal reformatted CT images of the brain. We have termed this the venous attenuation sign (VAS). This study evaluated the VAS as a marker for IIH assessing the transverse sinuses on sagittal reformatted non-contrast CT for the presence of a VAS in 25 patients with IIH and 24 control patients. Scans were independently assessed in a blinded fashion by three readers. The readers identified the VAS in 96% of patients with IIH; 83.3% of the control patients were negative for VAS. Our study supports the VAS as an additional imaging marker which may be incorporated into the evaluation of patients suspected to have this condition.

Using reduced catalysts for oxidation reactions: mechanistic studies of the "Periana-Catalytica" system for CH4 oxidation.

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.

Visceral obesity and colorectal cancer: are we missing the boat with BMI?

INTRODUCTION: Compared to subcutaneous fat, visceral fat is more metabolically active, leading to chronic inflammation and tumorigenesis. The aim of this study is to describe the effect of visceral obesity on colorectal cancer outcomes using computed tomography (CT) imaging to measure visceral fat. MATERIALS AND METHODS: We conducted a retrospective chart review of patients who underwent surgical resection for colorectal cancer. Visceral fat volume was measured by preoperative CT scans. Final analysis was performed by stratifying patients based on oncologic stage. RESULTS: Two hundred nineteen patients met the inclusion criteria, 111 viscerally obese and 108 nonobese. Body mass index (BMI) weakly correlated with visceral fat volume measurements (R (2) = 0.304). Whereas obese patients had no difference in survival when categorizing obesity by BMI, categorizing based on visceral fat volume resulted in significant differences in stage II and stage III patients. In stage II cancer, viscerally obese patients had a nearly threefold decrease in disease-free survival (hazard ratio (HR) = 2.72; 95 % confidence interval (CI) = 1.21, 6.10). In stage III cancer, viscerally obese patients had a longer time to recurrence (HR = 0.39; 95 % CI = 0.16, 0.99). CONCLUSION: This study shows that viscerally obese patients with stage II colorectal cancer are at higher risk for poor outcomes and should be increasingly considered for adjuvant chemotherapy.

Confocal fluorescence imaging enables noninvasive quantitative assessment of host cell populations in vivo following photodynamic therapy.

We report the use of optical imaging strategies to noninvasively examine photosensitizer distribution and physiological and host responses to 2-[1-hexyloxyethyl]-2 devinyl pyropheophorbide-a (HPPH)-mediated photodynamic therapy (PDT) of EMT6 tumors established in the ears of BALB/c mice. 24 h following intravenous (IV) administration of 1 µmol kg(-1) HPPH, wide-field fluorescence imaging reveals tumor selectivity with an approximately 2-3-fold differential between tumor and adjacent normal tissue. Confocal microscopy demonstrates a relatively homogeneous intratumor HPPH distribution. Labeling of host cells using fluorophore-conjugated antibodies allowed the visualization of Gr1(+)/CD11b(+) leukocytes and major histocompatibility complex class II (MHC-II)(+) cells in vivo. Imaging of the treated site at different time-points following irradiation shows significant and rapid increases in Gr1(+) cells in response to therapy. The maximum accumulation of Gr1(+) cells is found at 24 h post-irradiation, followed by a decrease at the 48 h time-point. Using IV-injected FITC-conjugated dextran as a fluorescent perfusion marker, we imaged tissue perfusion at different times post-irradiation and found that the reduced Gr1(+ )cell density at 48 h correlated strongly with functional damage to the vasculature as reported via decreased perfusion status. Dual color confocal imaging experiments demonstrates that about 90% of the anti-Gr1 cell population co-localized with anti-CD11b labeling, thus indicating that majority of the Gr1-labeled cells were neutrophils. At 24 h post-PDT, an approximately 2-fold increase in MHC-II+ cells relative to untreated control is also observed. Co-localization analysis reveals an increase in the fraction of Gr1(+) cells expressing MHC-II, suggesting that HPPH-PDT is stimulating neutrophils to express an antigen-presenting phenotype.