Microbubble Contrast-Enhanced Transcutaneous Ultrasound Enables Real-Time Spinal Cord Perfusion Monitoring Following Posterior Cervical Decompression.

INTRODUCTION: Ultrasound imaging is inexpensive, portable, and widely available. The development of a real-time transcutaneous spinal cord perfusion monitoring system would allow more precise targeting of mean arterial pressure goals following acute spinal cord injury (SCI). There has been no prior demonstration of successful real-time cord perfusion monitoring in humans. METHODS: Four adult patients who had undergone posterior cervical decompression and instrumentation at a single center were enrolled into this prospective feasibility study. All participants had undergone cervical laminectomies spanning ≥2 contiguous levels ≥2 months prior to inclusion with no history of SCI. The first two underwent transcutaneous ultrasound without contrast and the second two underwent contrast-enhanced ultrasound (CEUS) with intravenously injected microbubble contrast. RESULTS: Using non-contrast ultrasound with or without Doppler (n=2), the dura, spinal cord, and vertebral bodies were apparent however ultrasonography was insufficient to discern intramedullary perfusion or clear white-gray matter differentiation. With application of microbubble contrast (n=2), it was possible to quantify differential spinal cord perfusion within and between cross-sectional regions of the cord. Further, it was possible to quantify spinal cord hemodynamic perfusion using CEUS by measuring peak signal intensity and the time to peak signal intensity after microbubble contrast injection. Time-intensity curves were generated and area under the curves were calculated as a marker of tissue perfusion. CONCLUSION: CEUS is a viable platform for monitoring real-time cord perfusion in patients who have undergone prior cervical laminectomies. Further development has the potential to change clinical management acute SCI by tailoring treatments to measured tissue perfusion parameters.

Evaluation of Thyroid Ultrasound Report Quality and Assessing Effect of Adherence to Risk Stratification Criteria on Referral for Thyroid Nodule Biopsy.

PURPOSE: This study aims to evaluate the quality of diagnostic thyroid ultrasound reports and determine the impact of consistent adherence to 2015 American Thyroid Association (ATA) and 2017 American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) on reducing unnecessary referrals for thyroid nodule biopsy. MATERIALS AND METHODS: Reports from 291 referrals for thyroid nodule biopsy were included for retrospective report evaluation (males: 42; mean age: 56) according to 2015 ATA and ACR TI-RADS lexicon. Cytology results were collected for each patient. Two radiologists blinded to cytology results independently, retrospectively reviewed imaging of the referrals, and rescored them according to 2015 ATA and 2017 ACR TI-RADS risk stratification systems. Statistical analysis was completed using chi-square analysis and calculation of κ statistic for interobserver variability. RESULTS: No report completely addressed all features associated with malignancy. Over half of the reports did not include descriptors on echogenicity, shape, margin, or echogenic foci. In all, 9.3% of biopsies showed malignant histology. Rescoring of referrals demonstrated decrease in biopsy referrals by 55% as per 2017 ACR TI-RADS and 14% as per 2015 ATA (P < .0001). There was no impact on detection of malignancy with adherence to ATA or ACR criteria and less interobserver variability with application of 2017 ACR TI-RADS compared to 2015 ATA. CONCLUSION: Thyroid ultrasound report quality was found variable with respect to nodule description. Reports recommended biopsy based on nodule size with no detailed description of other imaging features. Adherence to risk stratification system would have resulted in significant reduction in the number of unnecessary biopsy referrals.

Evaluating the utility of computed tomography of the chest for gastric cancer staging

Background: International guidelines recommend routine computed tomography (CT) of the chest for gastric cancer staging. In Asian countries, where the incidence of pulmonary metastases is less than 1%, some guidelines recommend chest CT only for gastroesophageal junction cancers. If the incidence of pulmonary metastases is also low in Canada, routine chest CT may not be beneficial. Methods: We performed a retrospective review of patients in northern Alberta with newly diagnosed gastric cancer from January 2010 to July 2016. The primary aim of the study was to determine the incidence of pulmonary metastases at the time of diagnosis in this population. A secondary aim was to identify potential predictors of pulmonary metastases. We reviewed CT reports for pulmonary metastases. Imaging data also included liver metastases, abdominal lymphadenopathy (> 1 cm), ascites and omental or peritoneal nodules. Other data recorded were age, sex, primary tumour location, histologic type and tumour grade. Results: Four hundred and sixty-two patients (311 men, 151 women) were included in the analysis. Pulmonary metastases were identified in 25 patients (5.4%) overall and in 11 of 299 patients (3.7%) whose primary cancer was not in the cardia. On univariate analysis the presence of liver metastases (odds ratio [OR] 7.72, 95% confidence interval [CI] 3.24­18.37, p < 0.001) and abdominal lymphadenopathy (OR 3.30, 95% CI 1.29­8.48, p = 0.01) was associated with an increased risk of pulmonary metastases. Liver metastases retained statistical significance on multivariate analysis (OR 6.17, 95% CI 2.53­15.03, p < 0.001). Conclusion: The incidence of pulmonary metastases at the time of gastric cancer diagnosis is higher in northern Alberta than previously reported in Asian studies. Abdominal lymphadenopathy and liver metastases confer an elevated risk of pulmonary metastases.

Contexte: Les lignes directrices internationales recommandent une tomodensitométrie (TDM) thoracique de routine pour la stadification du cancer de l'estomac. Dans les pays asiatiques, où l'incidence des métastases pulmonaires est inférieure à 1 %, certaines lignes directrices recommandent la TMD thoracique seulement dans les cancers de la jonction gastro-oesophagienne. Si l'incidence des métastases pulmonaires est également faible au Canada, la TDM thoracique de routine pourrait ne pas être bénéfique. Méthodes: Nous avons procédé à une analyse rétrospective des patients du Nord de l'Alberta ayant reçu un diagnostic de cancer de l'estomac entre janvier 2010 et juillet 2016. L'objectif principal de l'étude était de déterminer l'incidence des métastases pulmonaires au moment du diagnostic chez cette population. Un objectif secondaire consistait à identifier les prédicteurs potentiels des métastases pulmonaires. Les rapports de TDM ont été passés en revue pour ce qui est des métastases pulmonaires. Les données provenant des épreuves d'imagerie incluaient aussi les métastases hépatiques, la lymphadénopathie abdominale (> 1 cm), l'ascite et les nodules épiploïques ou péritonéaux. Parmi les autres données consignées, mentionnons l'âge, le sexe, de même que la localisation, le type histologique et le grade de la tumeur principale. Résultats: Quatre cent soixante-deux patients (311 hommes, 151 femmes) ont été inclus dans l'analyse. Globalement, des métastases pulmonaires ont été observées chez 25 patients (5,4 %), et chez 11 patients sur 299 (3,7 %) dont le cancer principal ne se situait pas dans le cardia. À l'analyse univariée, la présence de métastases hépatiques (rapport des cotes [RC] 7,72, intervalle de confiance [IC] de 95 % de 3,24 à 18,37, p < 0,001) et de lymphadénopathie abdominale (RC 3,30, IC de 95 %, de 1,29 à 8,48, p = 0,01) a été associée à un risque accru de métastases pulmonaires. Les métastases hépatiques ont conservé leur portée statistique lors de l'analyse multivariée (RC 6,17, IC de 95 % de 2,53 à 15,03, p < 0,001). Conclusion: L'incidence des métastases pulmonaires au moment où un diagnostic de cancer de l'estomac est posé s'est révélée plus élevée dans le Nord de l'Alberta que dans les rapports d'études asiatiques précédentes. La lymphadénopathie abdominale et les métastases hépatiques confèrent un risque élevé de métastases pulmonaires.

Optimal CT scanning parameters for commonly used tumor ablation applicators.

PURPOSE: CT-beam hardening artifact can make tumor margin visualization and its relationship to the ablation applicator tip challenging. To determine optimal scanning parameters for commonly-used applicators. MATERIALS AND METHODS: Applicators were placed in ex-vivo cow livers with implanted mock tumors, surrounded by bolus gel. Various CT scans were performed at 440mA with 5mm thickness changing kVp, scan time, ASiR, scan type, pitch, and reconstruction algorithm. Four radiologists blindly scored the images for image quality and artifact quantitatively. RESULTS: A significant relationship between probe, kVp level, ASiR level, and reconstruction algorithm was observed concerning both image artifact and image quality (both p=<0.0001). Specifically, there are certain combinations of kVp, ASiR, and reconstruction algorithm that yield better images than other combinations. In particular, one probe performed equivalently or better than any competing probe considered here, regardless of kVp, ASiR, and reconstruction algorithm combination. CONCLUSION: The findings illustrate the overall interaction of the effects of kVp, ASiR, and reconstruction algorithm within and between probes, so that radiologists may easily reference optimal imaging performance for a certain combinations of kVp, ASiR, reconstruction algorithm and probes at their disposal. Optimum combinations for each probe are provided.

A practical imaging classification for the non-invasive differentiation of renal cell carcinoma into its main subtypes.

AIM: Renal cell carcinoma (RCC) is a heterogeneous disease which encompasses various subtypes that exhibit differing biologic behavior and imaging findings. Non-invasive subtype differentiation by imaging facilitates prognostication and treatment selection. The aim of the study was to evaluate the performance of a diagnostic imaging key based on tumor morphology, T2 signal intensity on MRI, and tumor vascularity for differentiating RCC into its subtypes. MATERIALS AND METHODS: Using a custom-designed diagnostic imaging key, three blinded fellowship-trained abdominal radiologists independently evaluated the cross-sectional imaging of 50 histologically proven RCCs and categorized these into subtypes in two sessions. The diagnostic performance of the imaging key was evaluated and compared to the baseline performance without the key. RESULTS: The 50 RCCs comprised 20 (40%) clear cell, 17 (34%) papillary, and 13 (26%) chromophobe tumors. All expert readers demonstrated an improvement in diagnostic accuracy by an average of 5.3% with the use of the key. The readers showed good to excellent diagnostic performance for clear cell RCC (area under the receiver operating curve, AUROC of 0.86-0.91) and papillary RCC (AUROC of 0.82-0.87), and fair performance with chromophobe RCC (AUROC of 0.67-0.77). The Reader-to-SOR (standard of reference) agreement increased from 0.53 (moderate) to 0.67 (good) with the use of the key. CONCLUSION: The diagnostic imaging key facilitates RCC subtype characterization and can be used as a decision support tool.

In vitro effects of a novel class of nitric oxide (NO) donating compounds on isolated human erectile tissue.

OBJECTIVES: The discovery of nitric oxide (NO) as one of the major effectors in penile erectile function has led to the development of various drugs which are able to elevate intracellular levels of cGMP. Recently, a novel class of NO donors have been developed, exemplified by S-nitroso-glutathione (GSNO) and S-nitroso-N-acetylcysteine-ethylester (SNACET), as well as compounds combining both phosphodiesterase inhibitory and NO donating activity, such as NCX 911 (sildenafil nitrate). In our study, we assessed the effects of GSNO, SNACET and NCX 911 on adrenergic tension and electrically induced relaxation of isolated human corpus cavernosum (HCC) and the in vitro formation of cGMP. Effects were compared to those of sodium nitroprusside (SNP) and sildenafil citrate. MATERIALS AND METHODS: Using the organ bath technique, drug effects were investigated on norepinephrine-induced tension and electrically induced relaxation of HCC. HCC strips were exposed to increasing concentrations of the compounds (0.01/0.1-10/100 microM) and the accumulation of cGMP was determined by means of a radioimmunoassay. RESULTS: Relaxation of HCC induced by means of electrical field stimulation (EFS) was abolished by tetrotodoxin, guanylyl cyclase inhibitor ODQ and nitric oxide synthase inhibitor L-NNA. Adrenergic tension of HCC strips was dose-dependently reversed by the drugs. The rank order of potency was: SNP > GSNO > NCX911 > sildenafil > SNACET. Compounds also dose-dependently increased EFS-induced amplitudes of relaxation (SNP > NCX911 > sildenafil > SNACET/GSNO). Relaxing effects of the drugs were paralleled by an increase in tissue levels of cGMP. CONCLUSION: Our results provide a rationale for future use of NCX 911 and S-nitrosothiols in the pharmacotherapy of erectile dysfunction (ED). Since the compounds are assumed to exert no considerable hemodynamic effects, they might be developed into new oral treatments for ED.