Sagar Patel

Small-Animal Imaging Using Clinical Positron Emission Tomography/Computed Tomography and Super-Resolution

Considering the high cost of dedicated small-animal positron emission tomography/computed tomography (PET/CT), an acceptable alternative in many situations might be clinical PET/CT. However, spatial resolution and image quality are of concern. The utility of clinical PET/CT for small-animal research and image quality improvements from super-resolution (spatial subsampling) were investigated. National Electrical Manufacturers Association (NEMA) NU 4 phantom and mouse data were acquired with a clinical PET/CT scanner, as both conventional static and stepped scans. Static scans were reconstructed with and without point spread function (PSF) modeling. Stepped images were postprocessed with iterative deconvolution to produce super-resolution images. Image quality was markedly improved using the super-resolution technique, avoiding certain artifacts produced by PSF modeling. The 2 mm rod of the NU 4 phantom was visualized with high contrast, and the major structures of the mouse were well resolved. Although not a perfect substitute for a state-of-the-art small-animal PET/CT scanner, a clinical PET/CT scanner with super-resolution produces acceptable small-animal image quality for many preclinical research studies.

Strategies to reduce artifacts and improve accuracy in multiplexed multi-pinhole small animal SPECT

Multi-pinhole collimation is commonly used to improve image quality in small animal SPECT. However multiplexed pinhole projections may introduce ambiguity in image reconstruction and may cause image artifacts and inaccurate quantification. We investigated strategies to optimize data sampling and minimize artifacts, including varying the pinhole configuration and providing a CT-based seed for iterative image reconstruction. Through computer simulations, we assessed the merits of these strategies in terms of quantitative accuracy, image noise, and lesion detection. Use of the CT-based seed for reconstruction significantly reduced multiplexing artifact and improved quantitative accuracy. Overall image quality was best with an imbalanced and irregular multiplexed pinhole configuration, which provided better lesion detection than the non-multiplexed configuration and with negligible artifact. Irregular pinhole patterns also appeared less sensitive to artifacts from unshielded background counts. Ultimately, the optimal pinhole configuration depends on the actual activity distribution. Having a collimator design where some pinholes may be selectively blocked may provide optimal flexibility for various mouse imaging applications.

Twitter Use in the Hematopoietic Cell Transplantation Community

Purpose of ReviewSocial media has revolutionized the access and exchange of information in healthcare. The microblogging platform Twitter has been used by blood and marrow transplant physicians over the last several years with increasing enthusiasm. We review the adoption of Twitter in the transplant community and its implications on clinical care, education, and research.Recent FindingsTwitter allows instantaneous access to the latest research publications, developments at national and international meetings, networking with colleagues, participation in advocacy, and promoting available clinical trials. Additionally, Twitter serves as a gateway for resources dedicated to education and support for patients undergoing transplantation.SummaryWe demonstrate the utilization and various applications in using Twitter among hematopoietic cell transplant healthcare professionals, patients, and other affiliated stakeholders. Professionalism concerns with clinician use of such social media platforms, however, also exist. Overall, Twitter has enhanced and increased the opportunities for engagement in the transplant community.

Prognostic Factors for Mortality among Day +100 Survivors after Allogeneic Hematopoietic Cell Transplantation

Although day +100 survival among allogeneic hematopoietic cell transplantation (HCT) recipients has improved over time, longer-term survival remains a challenge. The aim of this study was to identify prognostic factors for survival among patients surviving longer than 100 days using baseline characteristics and factors identified within the first 100 days after transplantation. Of 413 patients undergoing a first allogeneic HCT between 2006 and 2014, 335 survived >100 days post-transplantation. The majority underwent a myeloablative transplantation (75%) with a bone marrow (BM) (52%) graft source. One-year all-cause mortality (ACM) was 29%, with 16% relapse mortality (RM) and 12% nonrelapse mortality. In multivariable analysis, high-risk disease (hazard ratio [HR], 1.55; P = .003), non-cytomegalovirus infection (HR, 1.79; P = .003), more days hospitalized (HR, 1.16; P < .001), and relapse (HR, 4.38; P < .001) within the first 100 days were associated with increased risk of ACM. Patients with higher income (HR, .89; P = .024) and those who received BM (HR, .52; P < .001) or umbilical cord blood (HR, .40; P = .002) relative to peripheral blood stem cells had lower risk of ACM. Our study identifies risk factors for adverse long-term survival in 100-day survivors, a time point when patients frequently are discharged from transplantation centers. In addition to disease- and transplantation-related factors, low socioeconomic status was associated with worse long-term survival, highlighting the need for focused efforts to improve outcomes in vulnerable patient populations.

Prognostic models in predicting outcomes in myelodysplastic syndromes after hypomethylating agent failure

Abstract Myelodysplastic syndromes (MDS) are clonal stem cell disorders marked by bone marrow failure with varying degrees of cytopenias. MDS are characterized by the accumulation of complex genetic alterations that influence disease pathogenesis and outcomes. Given the heterogeneity of MDS patients, multiple prognostic scoring systems have been developed to predict patient outcomes. Most focus primarily on untreated patients in whom outcomes are predicted accurately only at diagnosis; their application dynamically, during the disease course and especially after hypomethylating agent (HMA) failure, may not be accurate. In this focused review, we discuss the utility of established MDS prognostic models and a novel tool at the time of HMA failure, along with the strengths and limitations of each.

Wireless Synchronization of a Multi-Pinhole Small Animal SPECT Collimation Device With a Clinical Scanner

A multi-pinhole collimation device for small animal single photon emission computed tomography (SPECT) uses the gamma camera detectors of a standard clinical SPECT scanner. The collimator and animal bed move independently of the detectors, and therefore their motions must be synchronized. One approach is manual triggering of the SPECT acquisition simultaneously with a programmed motion sequence for the device. However, some data blurring and loss of image quality result, and true electronic synchronization is preferred. An off-the-shelf digital gyroscope with integrated Bluetooth interface provides a wireless solution to device synchronization. The sensor attaches to the SPECT gantry and reports its rotational speed to a notebook computer controlling the device. Software processes the rotation data in real-time, averaging the signal and issuing triggers while compensating for baseline drift. Motion commands are sent to the collimation device with minimal delay, within approximately 0.5 second of the start of SPECT gantry rotation. Test scans of a point source demonstrate an increase in true counts and a reduction in background counts compared to manual synchronization. The wireless rotation sensor provides robust synchronization of the collimation device with the clinical SPECT scanner and enhances image quality.

Social Media and Hematopoietic Cell Transplantation: a Review of Online Resources and Communities

Purpose of ReviewSocial media has dramatically changed the access and exchange of information in healthcare and beyond. A variety of platforms and resources exist allowing blood and marrow transplant providers, researchers, and patients to interact. We review the adoption of social media by the transplantation community.Recent FindingsSocial media allows on-demand access to the latest developments at national and international meetings, newly published research articles, facilitates networking with colleagues, participation in advocacy, and promoting available clinical trials. For the modern transplantation provider, the scope and ease of access to these benefits are unparalleled. Social media serves as a gateway to access relevant resources and communities for both providers and patients as it pertains to transplantation.SummaryWe demonstrate the utilization and applications of social media among stem cell transplantation providers, patients, and other affiliated stakeholders. A variety of resources and communities have enhanced and increased the opportunities for engagement.

Patient-Reported Outcomes in Myelodysplastic Syndromes and MDS/MPN Overlap Syndromes: Stepping Onto the Stage with Changing Times

Quality of life (QOL) and symptom burden are important measures captured by patient-reported outcomes (PROs). Myelodysplastic and myelodysplastic/myeloproliferative (MDS/MPN) neoplasm overlap syndromes are notable for significant morbidity and mortality, including a wide spectrum of physical and psychosocial effects. Thus, the development and application of PROs can provide meaningful information to facilitate communication and assist in follow up care. Disease-specific measures can more accurately reflect the full breadth of functional restrictions and symptoms. While traditional endpoints include remission, relapse, and survival rates, adoption of PROs in myeloid neoplasm clinical trials can facilitate drug approval. Integration of PROs in myeloid neoplasms is an important measure to capture QOL and symptoms, which can improve disease management.