Scott Collins

Comparison of Intracerebral Hemorrhage Volume Calculation Methods and Their Impact on Scoring Tools.

Intracerebral hemorrhage (ICH) volumes are frequently used for prognostication and inclusion of patients in clinical trials. We sought to compare the original ABC/2 method and sABC/2, a simplified version with the planimetric method.

Evaluation of a Novel Thermal Accelerant for Augmentation of Microwave Energy during Image-guided Tumor Ablation

The primary challenge in thermal ablation of liver tumors (e.g. hepatocellular carcinoma and hepatic colorectal cancer) is the relatively high recurrence rate (~30%) for which incomplete ablation at the periphery of the tumor is the most common reason. In an attempt to overcome this, we have developed a novel thermal accelerant (TA) agent capable of augmenting microwave energy from a distance normally unattainable by a single microwave ablation antenna. This cesium-based block co-polymer compound transforms from a liquid to a gel at body temperature and is intrinsically visible by computed tomography. Using an agarose phantom model, herein we demonstrate that both the rate and magnitude of temperature increase during microwave ablation were significantly greater in the presence of TA when compared with controls. These results suggest robust augmentation of microwave energy, and may translate into larger ablation zone volumes within biologic tissues. Further work using in vivo techniques is necessary to confirm these findings.

Use of intraoperative computed tomography in complex craniofacial trauma: an example of on-table change in management.

The primary goals in repairing complex craniofacial fractures are restoration of occlusion and mastication, and anatomic reconstruction of a symmetric facial skeleton. Failure to accomplish these goals may result in the need for secondary operations. Recognition of malreduction may not be appreciated until review of a postoperative computed tomographic (CT) scan. Intraoperative CT scanning enables immediate on-table assessment of reduction and fixation, allowing alteration of the surgical plan as needed. We report using intraoperative CT scanning while repairing a panfacial injury in which malreduction was appreciated intraoperatively and corrected. Intraoperative CT can be used to improve outcomes and quality of complex facial fracture repair.

Effect of patient size on mean sterile water attenuation during multiphase CT examinations.

OBJECTIVE The purpose of this study was to determine the variability of attenuation measurements in a water phantom included in the FOV during multiphase 64-MDCT. SUBJECTS AND METHODS Ninety-seven consecutively registered patients undergoing multiphase kidney and liver protocol CT of the abdomen on the same 64-MDCT scanner had a sealed water bottle placed on their anterior abdomen during the examination. Region of interest (ROI) measurements of the mean attenuation (in HU) of the water bottle were made during the unenhanced, dynamic, and delayed phases of contrast enhancement. Generalized estimating equations were used to model mean attenuation in the ROI as a function of cross-sectional patient area, contrast phase, and protocol. Day of month and time of day were covariates. A phantom was created to model the patient study. RESULTS The mean attenuation values in the water bottle ROIs were -13.1 HU for the kidney protocol and -9.1 HU for the liver protocol in the unenhanced phase, -11.7 HU for the kidney and -9.5 HU for the liver protocol in the dynamic phase, and -11.9 HU for the kidney and 11.0 HU for the liver protocol in the delayed phase. Kidney protocol water bottle ROI attenuation values were lower than the liver values (p = 0.04). In all phases with both protocols, the values differed from 0 HU (all p < 0.0001). Water bottle ROI attenuation decreased as patient cross-sectional area increased (-0.01 HU/cm(2), p < 0.0001). Three patients had absolute water bottle attenuation changes greater than 20 HU between phases. Day of the month (p = 0.08) and time of day (p = 0.93) were not significant factors. Phantom data supported the study findings. CONCLUSION The mean attenuation of water decreased as patient diameter increased. Both artifactual enhancement and decrease in enhancement greater than 20 HU were found in three larger patients.

Exploratory Application of Augmented Reality/Mixed Reality Devices for Acute Care Procedure Training

Introduction Augmented reality (AR), mixed reality (MR), and virtual reality devices are enabling technologies that may facilitate effective communication in healthcare between those with information and knowledge (clinician/specialist; expert; educator) and those seeking understanding and insight (patient/family; non-expert; learner). Investigators initiated an exploratory program to enable the study of AR/MR use-cases in acute care clinical and instructional settings. Methods Academic clinician educators, computer scientists, and diagnostic imaging specialists conducted a proof-of-concept project to 1) implement a core holoimaging pipeline infrastructure and open-access repository at the study institution, and 2) use novel AR/MR techniques on off-the-shelf devices with holoimages generated by the infrastructure to demonstrate their potential role in the instructive communication of complex medical information. Results The study team successfully developed a medical holoimaging infrastructure methodology to identify, retrieve, and manipulate real patients’ de-identified computed tomography and magnetic resonance imagesets for rendering, packaging, transfer, and display of modular holoimages onto AR/MR headset devices and connected displays. Holoimages containing key segmentations of cervical and thoracic anatomic structures and pathology were overlaid and registered onto physical task trainers for simulation-based “blind insertion” invasive procedural training. During the session, learners experienced and used task-relevant anatomic holoimages for central venous catheter and tube thoracostomy insertion training with enhanced visual cues and haptic feedback. Direct instructor access into the learner’s AR/MR headset view of the task trainer was achieved for visual-axis interactive instructional guidance. Conclusion Investigators implemented a core holoimaging pipeline infrastructure and modular open-access repository to generate and enable access to modular holoimages during exploratory pilot stage applications for invasive procedure training that featured innovative AR/MR techniques on off-the-shelf headset devices.

The in vivo performance of a novel thermal accelerant agent used for augmentation of microwave energy delivery within biologic tissues during image-guided thermal ablation: a porcine study

Abstract Objectives: To investigate the effects of a novel caesium-based thermal accelerant (TA) agent on ablation zone volumes following in vivo microwave ablation of porcine liver and skeletal muscle, and to correlate the effects of TA with target organ perfusion. Materials and methods: This prospective study was performed following institutional animal care and use committee approval. Microwave ablation was performed in liver and resting skeletal muscle in eight Sus scrofa domesticus swine following administration of TA at concentrations of 0 mg/mL (control), 100 mg/mL and 250 mg/mL. Treated tissues were explanted and stained with triphenyltetrazolium chloride (TTC) for quantification of ablation zone volumes, which were compared between TA and control conditions. Hematoxylin and eosin (H&E) staining was also performed for histologic analysis. General mixed modelling with a log-normal distribution was used for all quantitative comparisons (p = 0.05). Results: A total of 28 ablations were performed in the liver and 18 in the skeletal muscle. The use of TA significantly increased ablation zone volumes in a dose-dependent manner in both the porcine muscle and liver (p < 0.01). Both the absolute mean ablation zone volume and percentage increase in ablation zone volume were greater in the resting skeletal muscle than in the liver. In one swine, a qualitative mitigation of heat sink effects was observed by TTC and H&E staining. Non-lethal polymorphic ventricular tachycardia was identified in one swine, treated with intravenous amiodarone. Conclusions: The use of a novel TA agent significantly increased mean ablation zone volumes following microwave ablation using a porcine model. The relationship between TA administration and ablation size was dose-dependent and inversely proportional to the degree of target organ perfusion, and a qualitative reduction in heat-sink effects was observed.

Computed Tomography-Guided Tumor Ablation: Analysis and Optimization of Computed Tomography Technique With Various Ablation Devices.

Purpose Ablation device-associated computed tomography beam hardening artifacts can make tumor margin visualization and its relationship to the ablation applicator tip challenging. Determine optimal scanning conditions for currently-used applicators. Materials and Methods Eleven applicators were placed in ex vivo cow livers with implanted mock tumors, surrounded by bolus gel. Various computed tomography scans were performed at 440 mA with 5 mm thickness changing kVp (80, 100, 120, 140), scan time (0.5, 0.7, 1.0, 2.0 seconds), adaptive statistical iterative reconstruction (ASiR) (30, 60, 90), scan type (helical, axial), pitch (0.5, 0.94, 1.37, 1.75), and reconstruction algorithm (soft, standard, lung). Two radiologists blindly scored the images for image quality and artifact quantitatively. Results Cool-tip single (CTS) RF electrode (Covidien) performed significantly better than all other devices in both perceived image quality and artifact while Boston Scientific 4.0 RF electrode (Boston Scientific) underperformed (all P < 0.001), when not controlling for any other factors. An effect for artifact (P < 0.001) was found for kVp and device: for most conditions, 80 kVp was rated significantly lower than all other levels, whereas 120 and 140 performed significantly better than 100 and 80. No significant effect with ASiR level and device was found for the artifact. There was an effect observed for artifact (P < 0.001) between scan time and probe: for most devices, 0.5 seconds was rated significantly lower than all other scan times, but CTS was resilient—showing no difference from other scan times. Algorithm did not show any significant effects. Taking into account ASiR, kVp, and time, CTS outperformed all other devices. Conclusions Higher kVp and scan times reduce device artifacts. It appears that CTS performs the best, even when considering ASiR, kVp, pitch, scan type, and scan time.

BioZorb tissue marker as seen on multiple imaging modalities

by immunohistochemistry should also be performed. Traumatic neuromas are reactive proliferations of nerves commonly seen associated with prior biopsy sites. There are no specific imaging findings for schwannoma in the breast. Ultrasound typically shows a hypoechoic circumscribed solid mass which can lack homogeneity. Most patients have undergone excisional biopsy following a diagnosis of schwannoma in a core biopsy. However, schwannoma is a benign tumor and it is reasonable to follow patients with imaging rather than have the lesion excised in most cases, provided the lesion is not growing in size and there is good radiologic-pathologic correlation.

Developing an open platform for evidence-based microwave ablation treatment planning and validation

The clinical utility of current thermal ablation planning tools is severely limited by treatment variability. We discuss the development of an open platform for evidence-based thermal ablation treatment planning and validation. Improved predictive treatment modeling and consistent outcome analysis are crucial components for useful planning and guidance tools.

Left Atrial Appendage Morphology and Embolic Stroke of Undetermined Source: A Cross-Sectional Multicenter Pilot Study

BACKGROUND The left atrial appendage (LAA) is the main source of thrombus in atrial fibrillation, and there is an association between non-chicken wing (NCW) LAA morphology and stroke. We hypothesized that the prevalence of NCW LAA morphology would be higher among patients with cardioembolic (CE) stroke and embolic stroke of undetermined source (ESUS) than among those with noncardioembolic stroke (NCS). METHODS This multicenter retrospective pilot study included consecutive patients with ischemic stroke from 3 comprehensive stroke centers who previously underwent a qualifying chest computed tomography (CT) to assess LAA morphology. Patients underwent inpatient diagnostic evaluation for ischemic stroke, and stroke subtype was determined based on ESUS criteria. LAA morphology was determined using clinically performed contrast enhanced thin-slice chest CT by investigators blinded to stroke subtype. The primary predictor was NCW LAA morphology and the outcome was stroke subtype (CE, ESUS, NCS). RESULTS We identified 172 patients with ischemic stroke who had a clinical chest CT performed. Mean age was 70.1 ± 14.3 years and 51.7% were male. Compared with patients with NCS, the prevalence of NCW LAA morphology was higher in patients with CE stroke (58.7% versus 46.3%, P = .1) and ESUS (58.8% versus 46.3%, P = .2), but this difference did not achieve statistical significance. CONCLUSION The prevalence of NCW LAA morphology may be similar in patients with ESUS and CE, and may be higher than that in those with NCS. Larger studies are needed to confirm these associations.