Evaluation of DISORDER: Retrospective Image Motion Correction for Volumetric Brain MRI in a Pediatric Setting

BACKGROUND AND PURPOSE:Head motion causes image degradation in brain MR imaging examinations, negatively impacting image quality, especially in pediatric populations. Here, we used a retrospective motion correction technique in children and assessed image quality improvement for 3D MR imaging acquisitions.MATERIALS AND METHODS:We prospectively acquired brain MR imaging at 3T using 3D sequences, T1-weighted MPRAGE, T2-weighted TSE, and FLAIR in 32 unsedated children, including 7 with epilepsy (age range, 2–18 years). We implemented a novel motion correction technique through a modification of k-space data acquisition: Distributed and Incoherent Sample Orders for Reconstruction Deblurring by using Encoding Redundancy (DISORDER). For each participant and technique, we obtained 3 reconstructions as acquired (Aq), after DISORDER motion correction (Di), and Di with additional outlier rejection (DiOut). We analyzed 288 images quantitatively, measuring 2 objective no-reference image quality metrics: gradient entropy (GE) and MPRAGE white matter (WM) homogeneity. As a qualitative metric, we presented blinded and randomized images to 2 expert neuroradiologists who scored them for clinical readability.RESULTS:Both image quality metrics improved after motion correction for all modalities, and improvement correlated with the amount of intrascan motion. Neuroradiologists also considered the motion corrected images as of higher quality (Wilcoxon z = −3.164 for MPRAGE; z = −2.066 for TSE; z = −2.645 for FLAIR; all P < .05).CONCLUSIONS:Retrospective image motion correction with DISORDER increased image quality both from an objective and qualitative perspective. In 75% of sessions, at least 1 sequence was improved by this approach, indicating the benefit of this technique in unsedated children for both clinical and research environments.

Head motion is a common cause of image degradation in brain MR imaging. Motion artifacts negatively impact MR image quality and therefore radiologists’ capacity to read the images, ultimately affecting patient clinical care.¹ Motion artifacts are more common in noncompliant patients,² but even in compliant adults, intrascan movement is reported in at least 10% of cases.³ For children who require high-resolution MR images, obtaining optimal image quality can be challenging, owing to the requirement to stay still over long durations needed for acquisition.⁴ Sedation can be an option, but it carries higher risks, costs, and preparation and recovery time.⁵In conditions such as intractable focal epilepsy, identification of an epileptogenic lesion is clinically important to guide surgical treatment. However, these lesions can be visually subtle, particularly in children in whom subtle cortical dysplasias are more common.⁶ Dedicated epilepsy MR imaging protocols use high-resolution 3D sequences to allow better cortical definition and free reformatting of orientation but involve acquisition times in the order of minutes, so data collection becomes more sensitive to motion.⁷For children in particular, multiple strategies are available for minimizing motion during MR examinations. Collaboration with play specialists using mock scanners and training or projecting a cartoon are good approaches to reduce anxiety.^8,9 These tools are not always available in clinical radiology and, even with these strategies, motion can still be an issue.¹⁰ Different scanning approaches to correct for intrascan motion have been proposed. Broadly, prospective methods track head motion in real time and modify the acquisition directions accordingly.¹¹ These approaches are applicable to a wide range of sequences but require optical systems with external tracking markers, sometimes uncomfortable or impractical, and extra setup can ultimately result in longer examinations. Furthermore, these approaches may also not be robust to continuous motion.^11-13 Retrospective techniques have also been proposed, in some cases relying on imaging navigators that are not compatible with all standard sequences or contrasts.¹²Here, we use a more general retrospective motion correction technique: Distributed and Incoherent Sample Orders for Reconstruction Deblurring by using Encoding Redundancy (DISORDER). In this method, k-space samples are reordered to enable retrospective motion correction during image reconstruction.¹⁴ Our hypothesis is that DISORDER improves clinical MR imaging quality and readability. To assess its use for clinical sequences, we acquired a dedicated epilepsy MR imaging protocol in 32 children across a wide age range. We used both objective image quality metrics and expert neuroradiologist ratings to evaluate the outcome after motion correction.     

Incidence,Characteristics, and Outcome of COVID-19 in Adults on Kidney Replacement Therapy: A Regionwide Registry Study

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Effects of Cling Film Draping Material on Body Temperature of Mice During Surgery

General anesthesia induces many systemic effects, including thermoregulatory impairment and subsequent perioperative hypothermia. Due to the animals’ small size, monitoring and maintaining body temperatures in laboratory rodents during anesthesia is important for successful surgical outcomes and prompt anesthetic recovery. Draping materials have the potential to aid in thermal support during surgical anesthesia. In this study, rectal and surface (infrared) temperatures were measured in C57BL/6 mice under isoflurane anesthesia every 5 min for the duration of a 35-min sham surgery. In addition to placement on a circulating water bath, mice (n = 6/group) were draped with commercial cling film (CF; Press''n Seal, Glad, Oakland, CA), a conventional paper drape (PD), or no drape (ND) during surgery. Results demonstrated that CF-draped animals had significantly higher rectal temperatures than nondraped animals. Furthermore, surface temperatures of CF-draped mice were considerably higher than those of both paper-draped and undraped animals. The data indicate that cling film is an effective material to help minimize hypothermia in mice and potentially in other laboratory rodents requiring general anesthesia.

Surgery and anesthesia introduce many challenges, especially in veterinary medicine, due to the diversity of species. One major challenge during general anesthesia involves changes in an animal''s thermoregulatory ability.^1,14 Body temperatures in mice and rats fall significantly during anesthesia if no thermal support is provided.^29,30 Hypothermia occurs due to drug-induced alterations to the thermoregulatory center, inadequate circulation, and a loss of body heat to the environment from evaporation, radiation, conduction, and convection.⁷ Mice are particularly susceptible to hypothermia, due to their large surface area per gram of body weight, which permits significant physiologic changes in response to fluctuations in the ambient temperature.³¹ Covering the animal''s body with towels, drapes, or blankets to reduce the area exposed to the environment can minimize heat loss.^6,7,13 Placing the animal on an insulated surface can limit conductive heat loss. In larger animals, warmed fluids can be given perioperatively, heated anesthetic gasses can be administered, and heated blankets and heat packs can be applied to body surfaces to provide exogenous heat.^1,7 Safer and more practical methods for rodents are circulating water heating blankets, thermal gel packs, and warming lamps, which are commonly used for thermal support during anesthesia.^5,14 Addressing all of these factors can contribute to maintaining normothermia during anesthesia.Risk of mortality is elevated during anesthesia and in the postoperative period, including in rodents.^1,13 Hypothermia induced by anesthesia can negatively affect rodents by altering vital parameters such as heart rate and blood pressure and delaying anesthetic recovery.^3,5,12,19 These risks require careful selection of an appropriate anesthetic protocol and careful monitoring of the patient throughout anesthesia until full recovery occurs. Strict anesthetic monitoring and the use of supplemental heat devices have been shown to reduce the likelihood of complications, improve overall postoperative recovery, and reduce mortality associated with surgical procedures.^1,7,15,16 However, due to these species’ small size, monitoring equipment must be specialized and is often costly. Cost-effective and practical alternative equipment and materials would facilitate monitoring and care of rodents.Various draping options are available for rodent surgery, and their use is vital for both sterile technique and heat retention. Traditionally, paper draping material has been a popular option, because it is relatively inexpensive and can be autoclaved together with surgical instruments.^15,16 Some institutions have adopted varying methods and types of draping, including no drape and paper draping. Commercial cling film (CF) has been used as draping due to its low cost, ease of use, and sterility straight out of the box.⁹ Our study team sought to evaluate the effects of draping material on intraoperative thermoregulation in mice by measuring rectal temperature (modified rectal probe) and surface temperature (infrared device) during a 35-min laparotomy procedure, with both temperature devices chosen for affordability and availability. We hypothesized that mice draped with CF would maintain a higher intraoperative body temperature under general anesthesia than would mice with traditional paper drapes or no drape.     

Does post dural puncture headache exist in idiopathic intracranial hypertension? A pilot study

Background/ObjectiveOccurrence of post-dural puncture headache (PDPH) after diagnostic lumbar puncture (LP) for idiopathic intracranial hypertension (IIH) may seem very unlikely in clinical practice. Nevertheless, it has been suggested by several studies, mainly in sub-group analyses. We aimed to evaluate the prevalence of PDPH in an IIH population and determine any eventual predictive factors of PDPH occurrence.MethodsWe conducted a retrospective multiple-center observational study. All newly diagnosed IIH patients who met the International Classification of Headache Disorders (ICHD-3) or the Dandy modified criteria were included from three different French hospitals. They all underwent LP following the same process with the same type of needle. We recorded PDPH occurring within five days after LP, as defined by ICHD-3 criteria.ResultsSeventy-four IIH patients were recruited, of whom 23 (31%) presented with PDPH. Neither classical risk factors for PDPH such as body mass index, age or gender, nor cerebrospinal fluid opening pressure, or specific IIH features were associated with occurrence of PDPH.ConclusionPDPH can occur after LP in IIH patients. Clinicians should be aware of this possible event during the IIH diagnosis assessment and should not automatically reconsider IIH diagnosis. PDPH prevention using an atraumatic needle and dedicated PDPH treatment seem relevant in IIH patients.     

Impact on Health-Related Quality of Life of Induction Chemotherapy Compared With Concurrent Cisplatin and Radiation Therapy in Patients With Head and Neck Cancer

AimsOrgan preservation, an important goal in the treatment of head and neck squamous cell carcinoma (HNSCC), may include induction chemotherapy and cisplatin with radiation therapy (CRT). To our knowledge, no reports have directly compared the impact of induction chemotherapy with that of CRT on health-related quality of life (HRQOL).Materials and methodsIn a phase II trial, we assessed the HRQOL of patients treated with induction chemotherapy followed by CRT. Eligible patients had stage III–IV HNSCC. HRQOL questionnaires were administered at baseline, the end of induction (EOI), the end of CRT (EOCRT) and after CRT. Functional Assessment of Cancer Therapy (FACT version 4) assessed HRQOL. We carried out a comparison of changes in HRQOL from baseline to EOI and from EOI to EOCRT. This trial is registered with ClinicalTrials.gov (NCT01566435).ResultsThirty patients were enrolled in the study. Most HRQOL questionnaires were completed (88%). The mean total FACT scores did not differ from baseline to EOI (general: 83.8 versus 79.1, P = 0.08; head and neck: 109.7 versus 105.8, P = 0.33; Total Outcome Index: 69.7 versus 62.3, P = 0.03; respectively, using P ≤ 0.01 to adjust for multiple simultaneous tests of differences). However, total FACT scores significantly worsened from EOI to EOCRT (79.1 versus 62.3, P = 0.01; 105.8 versus 74.2, P < 0.01; 62.3 versus 34.2, P = 0.01; respectively). Within domains, the head and neck cancer subscale score did not differ from baseline to EOI (median 28.5 versus 27.0, P = 0.69), but significantly worsened from EOI to EOCRT (27.0 versus 9.5, P < 0.01). Swallowing, oral pain and voice quality improved from baseline to EOI, but worsened from EOI to EOCRT. Physical and functional scores worsened from baseline to EOI and from EOI to EOCRT. The emotional well-being score improved from baseline to EOI but worsened from EOI to EOCRT.ConclusionsOverall, HRQOL did not significantly change from baseline to EOI but dramatically worsened from EOI to EOCRT.     

Validation of diffuse correlation spectroscopy against 15O-water PET for regional cerebral blood flow measurement in neonatal piglets

Diffuse correlation spectroscopy (DCS) can non-invasively and continuously asses regional cerebral blood flow (rCBF) at the cot-side by measuring a blood flow index (BFI) in non-traditional units of cm²/s. We have validated DCS against positron emission tomography using ¹⁵O-labeled water (¹⁵O-water PET) in a piglet model allowing us to derive a conversion formula for BFI to rCBF in conventional units (ml/100g/min). Neonatal piglets were continuously monitored by the BabyLux device integrating DCS and time resolved near infrared spectroscopy (TRS) while acquiring ¹⁵O-water PET scans at baseline, after injection of acetazolamide and during induced hypoxic episodes. BFI by DCS was highly correlated with rCBF (R = 0.94, p < 0.001) by PET. A scaling factor of 0.89 (limits of agreement for individual measurement: 0.56, 1.39)×10⁹× (ml/100g/min)/(cm²/s) was used to derive baseline rCBF from baseline BFI measurements of another group of piglets and of healthy newborn infants showing an agreement with expected values. These results pave the way towards non-invasive, cot-side absolute CBF measurements by DCS on neonates.     

Routine diagnostics for neural antibodies,clinical correlates,treatment and functional outcome

Objective

To determine frequencies, interlaboratory reproducibility, clinical ratings, and prognostic implications of neural antibodies in a routine laboratory setting in patients with suspected neuropsychiatric autoimmune conditions.

Methods

Earliest available samples from 10,919 patients were tested for a broad panel of neural antibodies. Sera that reacted with leucine-rich glioma-inactivated protein 1 (LGI1), contactin-associated protein-2 (CASPR2), or the voltage-gated potassium channel (VGKC) complex were retested for LGI1 and CASPR2 antibodies by another laboratory. Physicians in charge of patients with positive antibody results retrospectively reported on clinical, treatment, and outcome parameters.

Results

Positive results were obtained for 576 patients (5.3%). Median disease duration was 6 months (interquartile range 0.6–46 months). In most patients, antibodies were detected both in CSF and serum. However, in 16 (28%) patients with N-methyl-d-aspartate receptor (NMDAR) antibodies, this diagnosis could be made only in cerebrospinal fluid (CSF). The two laboratories agreed largely on LGI1 and CASPR2 antibody diagnoses (κ = 0.95). The clinicians (413 responses, 71.7%) rated two-thirds of the antibody-positive patients as autoimmune. Antibodies against the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), NMDAR (CSF or high serum titer), γ-aminobutyric acid-B receptor (GABABR), and LGI1 had ≥ 90% positive ratings, whereas antibodies against the glycine receptor, VGKC complex, or otherwise unspecified neuropil had ≤ 40% positive ratings. Of the patients with surface antibodies, 64% improved after ≥ 3 months, mostly with ≥ 1 immunotherapy intervention.

Conclusions

This novel approach starting from routine diagnostics in a dedicated laboratory provides reliable and useful results with therapeutic implications. Counseling should consider clinical presentation, demographic features, and antibody titers of the individual patient.

     

Uveitis in Patients Treated with CTLA-4 and PD-1 Checkpoint Blockade Inhibition

ABSTRACT

Purpose: To investigate the link between treatment with CTLA-4 and PD-1 checkpoint blockade inhibitors and the development of noninfectious uveitis.

Methods: A survey was distributed to uveitis specialists to identify patients who developed uveitis while receiving either PD-1 inhibitors pembrolizumab and nivolumab; PD-L1 inhibitors atezolizumab, avelumab, and durvalumab; or the CTLA-4 inhibitor ipilimumab.

Results: Fifteen patients from seven institutions were identified. The most common cancer diagnosis (13/15) was malignant melanoma. Fourteen patients had a new uveitis diagnosis following checkpoint blockade administration (six anterior uveitis, six panuveitis, one posterior uveitis, one anterior/intermediate combined); one patient developed optic neuritis. Uveitis was diagnosed within 6 months after drug initiation for 11/12 patients (median 63 days). Corticosteroid treatment was effective for most patients, although two patients had permanent loss of vision.

Conclusions: Patients on checkpoint inhibitor therapy should be educated to seek care if they develop ocular symptoms, and prompt referral to specialists should be incorporated into oncology protocols.     

Opioid overdose prevention education for medical students: Adopting harm reduction into mandatory clerkship curricula

Abstract

Background: Opioid overdose deaths constitute a public health crisis in the United States. Strategies for reducing opioid-related harm are underutilized due in part to clinicians’ low knowledge about harm reduction theory and limited preparedness to prescribe naloxone. Educational interventions are needed to improve knowledge and attitudes about, and preparedness to address, opioid overdoses among medical students. Methods: Informed by the Department of Veterans Affairs’ Overdose Education and Naloxone Distribution (OEND) program and narrative medicine, we developed and led a mandatory workshop on harm reduction for clerkship medical students. Using validated scales, we assessed students’ knowledge and attitudes about, and preparedness to address, opioid overdoses before the workshop and 6 weeks after. Results: Of 75 participating students from February through December 2017, 55 (73%) completed pre-workshop and 38 (51%) completed both pre- and post-workshop surveys. At baseline, 40 (73%) encountered patients with perceived at-risk opioid use in the previous 6 weeks, but only 11 (20%) recalled their teams prescribing naloxone for overdose prevention. Among those completing both surveys, knowledge about and preparedness to prevent overdose showed large improvement (Cohen’s d?=?0.85, P?<?.001; Cohen’s d?=?1.24, P?<?.001, respectively) and attitudes showed moderate improvement (Cohen’s d?=?0.32, P = .04). Discussion: Educational interventions grounded in harm reduction theory can increase students’ knowledge and attitudes about, and preparedness to address, opioid overdoses.