Customizable, biocompatible implants for dorsal nasal augmentation: An in vivo pilot study of eight polylactic acid scaffold designs.

Augmentation of the nasal dorsum often requires implantation of structural material. Existing methods include autologous, cadaveric or alloplastic materials and injectable hydrogels. Each of these options is associated with considerable limitations. There is an ongoing need for precise and versatile implants that produce long-lasting craniofacial augmentation. Four separate polylactic acid (PLA) dorsal nasal implant designs were 3D-printed. Two implants had internal PLA rebar of differing porosities and two were designed as "shells" of differing porosities. Shell designs were implanted without infill or with either minced or zested processed decellularized ovine cartilage infill to serve as a "biologic rebar", yielding eight total treatment groups. Scaffolds were implanted heterotopically on rat dorsa (N = 4 implants per rat) for explant after 3, 6, and 12 months followed by volumetric, histopathologic, and biomechanical analysis. Low porosity implants with either minced cartilage or PLA rebar infill had superior volume retention across all timepoints. Overall, histopathologic and immunohistochemical analysis showed a resolving inflammatory response with an M1/M2 ratio consistently favoring tissue regeneration over the study course. However, xenograft cartilage showed areas of degradation and pro-inflammatory infiltrate contributing to volume and contour loss over time. Biomechanical analysis revealed all constructs had equilibrium and instantaneous moduli higher than human septal cartilage controls. Biocompatible, degradable polymer implants can induce healthy neotissue ingrowth resulting in guided soft tissue augmentation and offer a simple, customizable and clinically-translatable alternative to existing craniofacial soft tissue augmentation materials. PLA-only implants may be superior to combination PLA and xenograft implants due to contour irregularities associated with cartilage degradation.

Bioengineering Full-scale auricles using 3D-printed external scaffolds and decellularized cartilage xenograft.

Reconstruction of the human auricle remains a formidable challenge for plastic surgeons. Autologous costal cartilage grafts and alloplastic implants are technically challenging, and aesthetic and/or tactile outcomes are frequently suboptimal. Using a small animal "bioreactor", we have bioengineered full-scale ears utilizing decellularized cartilage xenograft placed within a 3D-printed external auricular scaffold that mimics the size, shape, and biomechanical properties of the native human auricle. The full-scale polylactic acid ear scaffolds were 3D-printed based upon data acquired from 3D photogrammetry of an adult ear. Ovine costal cartilage was processed either through mincing (1 mm3) or zesting (< 0.5 mm3), and then fully decellularized and sterilized. At explantation, both the minced and zested neoears maintained the size and contour complexities of the scaffold topography with steady tissue ingrowth through 6 months in vivo. A mild inflammatory infiltrate at 3 months was replaced by homogenous fibrovascular tissue ingrowth enveloping individual cartilage pieces at 6 months. All ear constructs were pliable, and the elasticity was confirmed by biomechanical analysis. Longer-term studies of the neoears with faster degrading biomaterials will be warranted for future clinical application. STATEMENT OF SIGNIFICANCE: Accurate reconstruction of the human auricle has always been a formidable challenge to plastic surgeons. In this article, we have bioengineered full-scale ears utilizing decellularized cartilage xenograft placed within a 3D-printed external auricular scaffold that mimic the size, shape, and biomechanical properties of the native human auricle. Longer-term studies of the neoears with faster degrading biomaterials will be warranted for future clinical application.

Association between left atrial volume index and infarct volume in patients with ischemic stroke.

Background: Left atrial volume index (LAVI) is one marker of atrial myopathy, which is increasingly being recognized as a cause of cardioembolic stroke even in the absence of atrial fibrillation. Cardiac embolism is associated with larger strokes than other stroke mechanisms. The purpose of this study was to examine the association between LAVI and total brain infarct volume in patients with ischemic stroke. Methods: This was a retrospective study of 545 patients prospectively enrolled in the Cornell ActuE Stroke Academic Registry (CAESAR), which includes all acute ischemic stroke patients admitted to our hospital since 2011. LAVI measurements were obtained from our echocardiography image store system (Xclera, Philips Healthcare). Brain infarcts on diffusion-weighted images (DWI) were manually segmented and infarct volume was obtained on 3D Slicer. We used multiple linear regression models adjusted for age, sex, race, and vascular comorbidities including atrial fibrillation. Results: Among 2,945 CAESAR patients, 545 patients had both total infarct volume and LAVI measured. We found an association between LAVI and log-transformed total brain infarct volume in both unadjusted (ß = 0.018; p = 0.002) and adjusted (ß = 0.024; p = 0.001) models. Conclusion: We found that larger left atrial volume was associated with larger brain infarcts. This association was independent of known cardioembolic risk factors such as atrial fibrillation and heart failure. These findings support the concept that atrial myopathy may be a source of cardiac embolism even in the absence of traditionally recognized mechanisms such as atrial fibrillation.

Dual-Channel Stretchable, Self-Tuning, Liquid Metal Coils and Their Fabrication Techniques.

Flexible and stretchable radiofrequency coils for magnetic resonance imaging represent an emerging and rapidly growing field. The main advantage of such coil designs is their conformal nature, enabling a closer anatomical fit, patient comfort, and freedom of movement. Previously, we demonstrated a proof-of-concept single element stretchable coil design with a self-tuning smart geometry. In this work, we evaluate the feasibility of scaling this coil concept to a multi-element coil array and the associated engineering and manufacturing challenges. To this goal, we study a dual-channel coil array using full-wave simulations, bench testing, in vitro, and in vivo imaging in a 3 T scanner. We use three fabrication techniques to manufacture dual-channel receive coil arrays: (1) single-layer casting, (2) double-layer casting, and (3) direct-ink-writing. All fabricated arrays perform equally well on the bench and produce similar sensitivity maps. The direct-ink-writing method is found to be the most advantageous fabrication technique for fabrication speed, accuracy, repeatability, and total coil array thickness (0.6 mm). Bench tests show excellent frequency stability of 128 ± 0.6 MHz (0% to 30% stretch). Compared to a commercial knee coil array, the stretchable coil array is more conformal to anatomy and provides 50% improved signal-to-noise ratio in the region of interest.

Silicone-based materials with tailored MR relaxation characteristics for use in reduced coil visibility and in tissue-mimicking phantom design.

BACKGROUND: The development of materials with tailored signal intensity in MR imaging is critically important both for the reduction of signal from non-tissue hardware, as well as for the construction of tissue-mimicking phantoms. Silicone-based phantoms are becoming more popular due to their structural stability, stretchability, longer shelf life, and ease of handling, as well as for their application in dynamic imaging of physiology in motion. Moreover, silicone can be also used for the design of stretchable receive radio-frequency (RF) coils. PURPOSE: Fabrication of materials with tailored signal intensity for MRI requires knowledge of precise T1 and T2 relaxation times of the materials used. In order to increase the range of possible relaxation times, silicone materials can be doped with gadolinium (Gd). In this work, we aim to systematically evaluate relaxation properties of Gd-doped silicone material at a broad range of Gd concentrations and at three clinically relevant magnetic field strengths (1.5 T, 3 T, and 7 T). We apply the findings for rendering silicone substrates of stretchable receive RF coils less visible in MRI. Moreover, we demonstrate early stage proof-of-concept applicability in tissue-mimicking phantom development. MATERIALS AND METHODS: Ten samples of pure and Gd-doped Ecoflex silicone polymer samples were prepared with various Gd volume ratios ranging from 1:5000 to 1:10, and studied using 1.5 T and 3 T clinical and 7 T preclinical scanners. T1 and T2 relaxation times of each sample were derived by fitting the data to Bloch signal intensity equations. A receive coil made from Gd-doped Ecoflex silicone polymer was fabricated and evaluated in vitro at 3 T. RESULTS: With the addition of a Gd-based contrast agent, it is possible to significantly change T2 relaxation times of Ecoflex silicone polymer (from 213 ms to 20 ms at 1.5 T; from 135 ms to 17 ms at 3 T; and from 111.4 ms to 17.2 ms at 7 T). T1 relaxation time is less affected by the introduction of the contrast agent (changes from 608 ms to 579 ms; from 802.5 ms to 713 ms at 3 T; from 1276 ms to 979 ms at 7 T). First results also indicate that liver, pancreas, and white matter tissues can potentially be closely mimicked using this phantom preparation technique. Gd-doping reduces the appearance of the silicone-based coil substrate during the MR scan by up to 81%. CONCLUSIONS: Gd-based contrast agents can be effectively used to create Ecoflex silicone polymer-based phantoms with tailored T2 relaxation properties. The relative low cost, ease of preparation, stretchability, mechanical stability, and long shelf life of Ecoflex silicone polymer all make it a good candidate for "MR invisible" coil development and bears promise for tissue-mimicking phantom development applicability.

Percutaneous closure of giant aneurysmal coronary artery-to-coronary sinus fistulae with guidance from three-dimensional printed models: a case series.

Background: Coronary artery fistulae are abnormal communications of coronary arteries with systemic vasculature, pulmonary vasculature, or cardiac chambers. Use of multimodality imaging can be paramount to understanding anatomical and functional features of these complex vascular lesions, therefore optimizing success of potential curative interventions. Case summary: We present two patients with incidentally discovered giant aneurysmal coronary arteries with distal fistulous connections to the coronary sinus, which were successfully closed percutaneously with Amplatzer Septal Occluders using the assistance of three-dimensional (3D) printed heart models. Conclusion: Computed tomography-guided reconstruction with 3D multiplanar, multicolour printed models can help augment visuospatial understanding of the size, origin, course, and drainage of giant aneurysmal coronary artery-to-coronary sinus fistulae, and with manual bench testing can assist with choosing accurately sized and shaped devices for closure.

Segmentation of Vestibular Schwannomas on Postoperative Gadolinium-Enhanced T1-Weighted and Noncontrast T2-Weighted Magnetic Resonance Imaging Using Deep Learning.

OBJECTIVE: Surveillance of postoperative vestibular schwannomas currently relies on manual segmentation and measurement of the tumor by content experts, which is both labor intensive and time consuming. We aimed to develop and validate deep learning models for automatic segmentation of postoperative vestibular schwannomas on gadolinium-enhanced T1-weighted magnetic resonance imaging (GdT1WI) and noncontrast high-resolution T2-weighted magnetic resonance imaging (HRT2WI). STUDY DESIGN: A supervised machine learning approach using a U-Net model was applied to segment magnetic resonance imaging images into pixels representing vestibular schwannoma and background pixels. SETTING: Tertiary care hospital. PATIENTS: Our retrospective data set consisted of 122 GdT1WI and 122 HRT2WI studies in 82 postoperative adult patients with a vestibular schwannoma treated with subtotal surgical resection between September 1, 2007, and April 17, 2018. Forty-nine percent of our cohort was female, the mean age at the time of surgery was 49.8 years, and the median time from surgery to follow-up scan was 2.26 years. INTERVENTIONS: N/A. MAIN OUTCOME MEASURES: Tumor areas were manually segmented in axial images and used as ground truth for training and evaluation of the model. We measured the Dice score of the predicted segmentation results in comparison to manual segmentations from experts to assess the model's accuracy. RESULTS: The GdT1WI model achieved a Dice score of 0.89, and the HRT2WI model achieved a Dice score of 0.85. CONCLUSION: We demonstrated that postoperative vestibular schwannomas can be accurately segmented on GdT1WI and HRT2WI without human intervention using deep learning. This artificial intelligence technology has the potential to improve the postoperative surveillance and management of patients with vestibular schwannomas.

Overview of Interventional Pulmonology for Radiologists.

Interventional pulmonology is a growing field specializing in minimally invasive procedures of the mediastinum, lungs, airways, and pleura. These procedures have both diagnostic and therapeutic indications and are performed for benign and malignant diseases. Endobronchial US has been combined with transbronchial needle aspiration to extend tissue sampling beyond the airways and into the lungs and mediastinum. Recent innovations extending the peripheral access of bronchoscopy include electromagnetic navigational bronchoscopy and thinner bronchoscopes. An important indication for therapeutic bronchoscopy is the relief of central airway obstruction, which may be severe and life threatening. Techniques for restoring patency of the central airways include mechanical debulking and multiple modalities for ablation, stent placement, and balloon bronchoplasty. Bronchoscopic lung volume reduction improves quality of life in certain patients with severe emphysema and is an important less invasive alternative to lung volume reduction surgery. Bronchial thermoplasty is likewise a nonpharmacologic treatment in patients with severe uncontrolled asthma. Many of these procedures have unique selection criteria that require precise evaluations at preprocedure imaging. Postprocedure imaging is also essential in determining outcome success and the presence of complications. Radiologists should be familiar with these procedures as well as the relevant imaging features in both planning and later surveillance. Evolving techniques that may become more widely available in the near future include robotic-assisted bronchoscopy, bronchoscopic transparenchymal nodule access, transbronchial cryobiopsy, ablation of early-stage cancers, and endobronchial intratumoral chemotherapy. An invited commentary by Wayne et al is available online. ©RSNA, 2021.

Stretchable self-tuning MRI receive coils based on liquid metal technology (LiquiTune).

Magnetic resonance imaging systems rely on signal detection via radiofrequency coil arrays which, ideally, need to provide both bendability and form-fitting stretchability to conform to the imaging volume. However, most commercial coils are rigid and of fixed size with a substantial mean offset distance of the coil from the anatomy, which compromises the spatial resolution and diagnostic image quality as well as patient comfort. Here, we propose a soft and stretchable receive coil concept based on liquid metal and ultra-stretchable polymer that conforms closely to a desired anatomy. Moreover, its smart geometry provides a self-tuning mechanism to maintain a stable resonance frequency over a wide range of elongation levels. Theoretical analysis and numerical simulations were experimentally confirmed and demonstrated that the proposed coil withstood the unwanted frequency detuning typically observed with other stretchable coils (0.4% for the proposed coil as compared to 4% for a comparable control coil). Moreover, the signal-to-noise ratio of the proposed coil increased by more than 60% as compared to a typical, rigid, commercial coil.

An Open-Source Three-Dimensionally Printed Laryngeal Model for Injection Laryngoplasty Training.

OBJECTIVES/HYPOTHESIS: A limited number of three-dimensionally (3D)-printed laryngeal simulators have been described in the literature, only one of which is specifically designed for percutaneous injection laryngoplasty (PIL) training and is currently of limited availability. This study describes the development and evaluation of a high-fidelity, open-source, low-cost 3D-printed simulator for PIL training, improving on existing models. STUDY DESIGN: Simulator design and survey evaluation. METHODS: Computed tomography scans of the upper airways were processed with 3D Slicer to generate a computer model of the endolarynx. Blender and Fusion 360 were used to refine the mucosal model and develop casts for silicone injection molding. The casted endolaryngeal structures were inserted into a modified version of a publicly available laryngeal cartilage model. The final models were evaluated by 10 expert laryngologists using a customized version of the Michigan Standard Simulation Experience Scale. Internal consistency and interrater reliability of the survey were evaluated using Cronbach's α and intraclass correlation, respectively. RESULTS: Expert laryngologists highly rated the model for measures of fidelity, educational value, and overall quality (mean = 4.8, standard deviation = 0.5; 1 = strongly disagree, 5 = strongly agree). All reviewers rated the model as ready for use as is or with slight modifications. The filament needed for one cartilage model costs $0.96, whereas the silicone needed for one soft-tissue model costs $1.89. CONCLUSIONS: Using 3D-printing technology, we successfully created the first open-source, low-cost, and anatomically accurate laryngeal model for injection laryngoplasty training. Our simulator is made freely available for download on Wikifactory with step-by-step tutorials for 3D printing, silicone molding, assembly, and use. LEVEL OF EVIDENCE: NA Laryngoscope, 131:E890-E895, 2021.

Effects of Ethanol on Synaptic Plasticity and NMDA Currents in the Juvenile Rat Dentate Gyrus.

BACKGROUND AND OBJECTIVES: We examined how acute ethanol (EtOH) exposure affects long term depression (LTD) in the dentate gyrus (DG) of the hippocampus in juvenile rats. EtOH is thought to directly modulate n-methyl-D-aspartate receptor (NMDAr) currents, which are believed important for LTD induction. LTD in turn is believed to play an important developmental role in the hippocampus by facilitating synaptic pruning. METHODS: Hippocampal slices (350µm) were obtained at post-natal day (PND) 14, 21, or 28. Field EPSPs (excitatory post-synaptic potential) or whole-cell EPSCs (excitatory post-synaptic conductance) were recorded from the DG (dentate gyrus) in response to medial perforant path activation. Low-frequency stimulation (LFS; 900 pulses; 120 s pulse) was used to induce LTD. RESULTS: Whole-cell recordings indicated that EtOH exposure at 50mM did not significantly impact ensemble NMDAr EPSCs in slices obtained from animals in the PND14 or 21 groups, but it reliably produced a modest inhibition in the PND28 group. Increasing the concentration to 100 mM resulted in a modest inhibition of NMDAr EPSCs in all three groups. LTD induction and maintenance was equivalent in magnitude in all three age groups in control conditions, however, and surprisingly, NMDA antagonist AP5 only reliably blocked LTD in the PND21 and 28 age groups. The application of 50 mM EtOH attenuated LTD in all three age groups, however increasing the concentration to 100 mM did not reliably inhibit LTD. CONCLUSIONS: These results indicate that the effect of EtOH on NMDAr-EPSCs recorded from DGCs is both age and concentration dependent in juveniles. Low concentrations of EtOH can attenuate, but did not block LTD in the DG. The effects of EtOH on LTD do not align well with it's effects on NNMDA receptors.

Skull Base 3D Modeling of Rigid Buttress for Gasket-Seal Closure Using Operative Endoscopic Imaging: Cadaveric Feasibility.

Surgical defect closure following endonasal transsphenoidal tumor resection is a critical component of procedural success. Three-dimensional (3D) modeling of relevant skull base anatomy during resection can potentially facilitate design of a custom rigid buttress for gasket-seal closure; however, access to conventional cross-sectional imaging intraoperatively is limited and cumbersome. Endoscopic imaging, by contrast, is always available. This work demonstrates the feasibility of 3D modeling of the visible skull base through structure-from-motion photogrammetric postprocessing techniques, providing a suitable template to design a gasket-seal buttress. Additionally, endoscopic 3D reconstruction of skull base surface anatomy may represent a more robust depiction of the surgical defect than is available by conventional 3D modeling with computed tomography, which suboptimally recapitulates very thin bones and mucosal surfaces typical of this regional anatomy.

Manufacturing Better Outcomes in Cardiovascular Intervention: 3D Printing in Clinical Practice Today.

PURPOSE OF REVIEW: Describe and evaluate the integration of 3D printing-related innovations into current cardiovascular treatment paradigms and examine the state of regulatory and reimbursement hurdles ahead. RECENT FINDINGS: Mounting years of clinical experience have established the utility of printed models of patient anatomy in numerous treatment and teaching scenarios, most notably as pre- and intra-procedural planning tools guiding decision-making for congenital heart disease and catheter-based interventions. In part due to a continued lack of reimbursement and under-defined (and slow to evolve) regulatory status, these use cases remain largely investigational even as they grow increasingly routine. Patients, physicians, and/or imaging centers therefore remain burdened by the associated cost to create such models, and the perceptual and decision-making enhancements, while demonstrable and significant, still may not clearly or independently justify a potentially high cost. Simulation and implantable device applications may represent a deeper well of unrealized value in cardiovascular intervention; however, further development of these applications relies on-and is throttled by-progress in material science and tissue-engineering research. The relevance of simulation applications in recent years is also now in competition with digital analogs including augmented and virtual reality. Innovative incorporation of alternative manufacturing processes such as porous scaffold infusion, injection molding, and vascular mesh forming can provide immediate access to more realistic tissue-mimicking materials and custom implantable devices, while comparable and directly printable materials continue to be developed. Tissue-engineering applications remain years if not decades away from a more substantive role in translatable clinical research. Regulatory challenges associated with in-house manufacture of implantable investigational devices are complex and subject to change, and the success of some in navigating these hurdles in non-cardiovascular applications is instructive and encouraging. Complex geometries characterizing cardiovascular anatomy are an ideal use case for translating the perceptual advantages of printed models of patient anatomy into better decision-making, especially so in the setting of congenital or post-surgical anatomy. Procedural planning applications take further advantage of the demonstrably robust dimensional reproduction of patient anatomy, with notably rapid integration into surgical and catheter-based intervention workflows. Despite a continued lack of codification in the healthcare system, 2018 could be a milestone year for 3D printing services, pending a successful application for a CPT Category III designation.

Establishing Normal Values for Shear-Wave Elastography of the Renal Cortex in Healthy Adults.

BACKGROUND: Shear-wave elastography of the kidney has emerged as a potential clinical application of this novel imaging tool. However, normal velocity values for shear-wave elastography involving the cortex of healthy kidneys have not been definitively established, and both inter- and intraobserver reliability has yet to be comprehensively evaluated. METHODS: This prospective study involved ultrasound examination of 11 healthy adults. Shear-wave velocity values were obtained at the renal cortex in the longitudinal and transverse planes by both junior (fellow) and senior (attending) radiologists. RESULTS: The mean shear-wave velocity values ranged between 2.82 and 2.9 m/s, which did not vary significantly between observers (junior vs. senior) or method of measurement (longitudinal vs. transverse planes), P = 0.533. However, there was a wide variation for these measurements (0.51-4.99 m/s). Separate analysis of the measurement depth demonstrated no statistically significant association with the shear-wave velocity values, P = 0.477. CONCLUSION: Our results agree with previous publications and help establish normal shear-wave velocity values and their range for the renal cortex in adults.

Shear Wave Elastography to Assess False Vocal Folds in Healthy Adults: A Feasibility Study.

OBJECTIVES: The aim of the study was to investigate the feasibility of using ultrasound shear wave elastography to quantify mechanical properties and movement symmetry of false vocal folds positioned in adduction and abduction. METHODS: We prospectively measured the shear wave velocity (SWV) within the bilateral false vocal folds in 10 healthy adults using acoustic radiation force impulse imaging. From a transcutaneous approach at the level of thyroid cartilage, 5 SWV measurements were obtained within each side of the false vocal folds twice in adduction and again in abduction for each participant. Configuration-related differences in the SWV within false vocal folds were compared between adduction and abduction, in addition to differences between the right and left false vocal folds and between men and women, by a paired t test. We developed an SWV index [(SWVgreater - SWVlesser )/SWVgreater ] to assess movement symmetry between the right and left false vocal folds. Intraobserver agreement on repeated measures was examined by the intraclass correlation coefficient. RESULTS: The 10 participants included 5 men and 5 women. We observed that the SWV within false vocal folds was significantly higher in adduction than in abduction (P < .001). The SWV within false vocal folds in adduction was also significantly higher in women compared to men (P < .001). There was no significant difference in the SWV between the right and left false vocal folds in adduction or in abduction or between men and women in abduction (P > .05). The mean SWV index was 0.05 (range, 0.03-0.07). The intraclass correlation coefficient for intraobserver agreement was 0.89 (P < .001). CONCLUSIONS: Shear wave elastography seems to be feasible to quantify mechanical properties and evaluate the symmetry of false vocal folds in healthy adults.

SMA-like syndrome with variant mesenteric venous anatomy.

Superior mesenteric artery (SMA) syndrome refers to the constellation of symptoms that are associated with intermittent obstruction of the duodenum due to vascular compression. We present a case of SMA-like syndrome related to variant mesenteric venous drainage in the setting of normal aortomesenteric angle (AMA) and borderline reduced aortomesenteric distance (AMD).

Single-Center Experience Implementing the LOINC-RSNA Radiology Playbook for Adult Abdomen/Pelvis CT and MR Procedures Using a Semi-Automated Method.

The LOINC-RSNA Radiology Playbook represents the future direction of standardization for radiology procedure names. We developed a software solution ("RadMatch") utilizing Python 2.7 and FuzzyWuzzy, an open-source fuzzy string matching algorithm created by SeatGeek, to implement the LOINC-RSNA Radiology Playbook for adult abdomen and pelvis CT and MR procedures performed at our institution. Execution of this semi-automated method resulted in the assignment of appropriate LOINC numbers to 86% of local CT procedures. For local MR procedures, appropriate LOINC numbers were assigned to 75% of these procedures whereas 12.5% of local MR procedures could only be partially mapped. For the standardized local procedures, only 63% of CT and 71% of MR procedures had corresponding RadLex Playbook identifier (RPID) codes in the LOINC-RSNA Radiology Playbook, which limited the utility of RPID codes. RadMatch is a semi-automated open-source software tool that can assist radiology departments seeking to standardize their radiology procedures via implementation of the LOINC-RSNA Radiology Playbook.

Mutational profiles of breast cancer metastases from a rapid autopsy series reveal multiple evolutionary trajectories.

Heterogeneity within and among tumors in a metastatic cancer patient is a well-established phenomenon that may confound treatment and accurate prognosis. Here, we used whole-exome sequencing to survey metastatic breast cancer tumors from 5 patients in a rapid autopsy program to construct the origin and genetic development of metastases. Metastases were obtained from 5 breast cancer patients using a rapid autopsy protocol and subjected to whole-exome sequencing. Metastases were evaluated for sharing of somatic mutations, correlation of copy number variation and loss of heterozygosity, and genetic similarity scores. Pathological features of the patients' disease were assessed by immunohistochemical analyses. Our data support a monoclonal origin of metastasis in 3 cases, but in 2 cases, metastases arose from at least 2 distinct subclones in the primary tumor. In the latter 2 cases, the primary tumor presented with mixed histologic and pathologic features, suggesting early divergent evolution within the primary tumor with maintenance of metastatic capability in multiple lineages. We used genetic and histopathological evidence to demonstrate that metastases can be derived from a single or multiple independent clones within a primary tumor. This underscores the complexity of breast cancer clonal evolution and has implications for how best to determine and implement therapies for early- and late-stage disease.

Imaging Properties of 3D Printed Materials: Multi-Energy CT of Filament Polymers.

Clinical applications of 3D printing are increasingly commonplace, likewise the frequency of inclusion of 3D printed objects on imaging studies. Although there is a general familiarity with the imaging appearance of traditional materials comprising common surgical hardware and medical devices, comparatively less is known regarding the appearance of available 3D printing materials in the consumer market. This work detailing the CT appearance of a selected number of common filament polymer classes is an initial effort to catalog these data, to provide for accurate interpretation of imaging studies incidentally or intentionally including fabricated objects. Furthermore, this information can inform the design of image-realistic tissue-mimicking phantoms for a variety of applications, with clear candidate material analogs for bone, soft tissue, water, and fat attenuation.

Another look at ultrasound and magnetic resonance imaging for diagnosis of placenta accreta.

OBJECTIVE: To compare the ability of magnetic resonance imaging (MRI) and ultrasound (US) in the diagnosis of placenta accreta, to examine the success of various sonographic and MRI features to correctly predict invasive placenta, and to define a specific role for MRI in placenta accreta. METHODS: After Institutional Review Board approval, a blinded retrospective review was undertaken of US and MRI findings from 45 patients who had an obstetrical US and placental MRI between August 2006 and January 2012. Correlation with clinical history and pathologic findings was performed. RESULTS: US and MRI had similar sensitivity, specificity and positive and negative predictive values for placenta accreta. The best predictors of invasion by US were loss of the myometrial mantle, increased intraplacental vascularity and loss of the bladder wall echogenicity. The best predictors of invasion by MRI were loss of retroplacental myometrial mantle, a heterogeneous placenta, and intraplacental hemorrhage. Body mass index (BMI) did not affect the ability to make a diagnosis by either US or MRI. MRI proved effective in better evaluation of a posterior placenta with suspicion of placenta accreta. There was modality disagreement in 11 of 45 cases and MRI was correct in 9 of these 11 cases, all true negative (TN) cases. CONCLUSIONS: MRI should be considered in any case with posterior placenta previa and suspicion of accreta, in any case with clinical suspicion for accreta and discordant US findings, and in any case in which percreta is suspected.