Automation of ultrasonographic optic nerve sheath diameter measurement using convolutional neural networks.

BACKGROUND AND PURPOSE: Ultrasonographic optic nerve sheath (ONS) diameter is a noninvasive intracranial pressure (ICP) surrogate. ICP is monitored invasively in specialized intensive care units. Noninvasive ICP monitoring is important in less specialized settings. However, noninvasive ICP monitoring using ONS diameter (ONSD) is limited by the need for experts to obtain and perform measurements. We aim to automate ONSD measurements using a deep convolutional neural network (CNN) with a novel masking technique. METHODS: We trained a CNN to reproduce masks that mark the ONS. The edges of the mask are defined by an expert. Eight models were trained with 1000 epochs per model. The Dice-similarity-coefficient-weighted averaged outputs of the eight models yielded the final predicted mask. Eight hundred and seventy-three images were obtained from 52 transorbital cine-ultrasonography sessions, performed on 46 patients with brain injuries. Eight hundred and fourteen images from 48 scanning sessions were used for training and validation and 59 images from four sessions for testing. Bland-Altman and Pearson linear correlation analyses were used to evaluate the agreement between CNN and expert measurements. RESULTS: Expert ONSD measurements and CNN-derived ONSD estimates had strong agreement (r = 0.7, p < .0001). The expert mean ONSD (standard deviation) is 5.27 mm (0.43) compared to CNN mean estimate of 5.46 mm (0.37). Mean difference (95% confidence interval, p value) is 0.19 mm (0.10-0.27 mm, p = .0011), and root mean square error is 0.27 mm. CONCLUSION: A CNN can learn ONSD measurement using masking without image segmentation or landmark detection.

Optic nerve sheath diameter and spaceflight: defining shortcomings and future directions.

Neuro-ocular changes during long-duration space flight are known as spaceflight-associated neuro-ocular syndrome (SANS). The ability to detect, monitor, and prevent SANS is a priority of current space medicine research efforts. Optic nerve sheath diameter (ONSD) measurement has been used both terrestrially and in microgravity as a proxy for measurements of elevated intracranial pressure. ONSD shows promise as a potential method of identifying and quantitating neuro-ocular changes during space flight. This review examines 13 studies measuring ONSD and its relationship to microgravity exposure or ground-based analogs, including head-down tilt, dry immersion, or animal models. The goal of this correspondence is to describe heterogeneity in the use of ONSD in the current SANS literature and make recommendations to reduce heterogeneity in future studies through standardization of imaging modalities, measurement techniques, and other aspects of study design.

Quality assessment of optic nerve sheath diameter ultrasonography: Scoping literature review and Delphi protocol.

BACKGROUND AND PURPOSE: The optic nerve is surrounded by the extension of meningeal coverings of the brain. When the pressure in the cerebrospinal fluid increases, it causes a distention of the optic nerve sheath diameter (ONSD), which allows the use of this measurement by ultrasonography (US) as a noninvasive surrogate of elevated intracranial pressure. However, ONSD measurements in the literature have exhibited significant heterogeneity, suggesting a need for consensus on ONSD image acquisition and measurement. We aim to establish a consensus for an ONSD US Quality Criteria Checklist (ONSD US QCC). METHODS: A scoping systematic review of published ultrasound ONSD imaging and measurement criteria was performed to guide the development of a preliminary ONSD US QCC that will undergo a modified Delphi study to reach expert consensus on ONSD quality criteria. The protocol of this modified Delphi study is presented in this manuscript. RESULTS: A total of 357 ultrasound studies were included in the review. Quality criteria were evaluated under five categories: probe selection, safety, positioning, image acquisition, and measurement. CONCLUSIONS: This review and Delphi protocol aim to establish ONSD US QCC. A broad consensus from this process may reduce the variability of ONSD measurements in future studies, which would ultimately translate into improved ONSD clinical applications. This protocol was reviewed and endorsed by the German Society of Ultrasound in Medicine.

Acute encephalitis, myoclonus and Sweet syndrome after mRNA-1273 vaccine.

A patient presented with fever, generalised rash, confusion, orofacial movements and myoclonus after receiving the first dose of mRNA-1273 vaccine from Moderna. MRI was unremarkable while cerebrospinal fluid showed leucocytosis with lymphocyte predominance and hyperproteinorrachia. The skin evidenced red, non-scaly, oedematous papules coalescing into plaques with scattered non-follicular pustules. Skin biopsy was consistent with a neutrophilic dermatosis. The patient fulfilled the criteria for Sweet syndrome. A thorough evaluation ruled out alternative infectious, autoimmune or malignant aetiologies, and all manifestations resolved with glucocorticoids. While we cannot prove causality, there was a temporal correlation between the vaccination and the clinical findings.

Ultrasound measurement of optic nerve sheath diameter pre- and post-lumbar puncture.

BACKGROUND: To test the hypothesis that optic nerve sheath diameter (ONSD) correlates with real-time changes in intracranial pressure, we performed ultrasound measurements of the ONSD in ambulatory patients undergoing elective lumbar puncture (LP). We conducted a prospective cohort study, including adult patients undergoing LP in a non-emergent setting. We measured ONSD perpendicular to the optic nerve at 3 mm behind the globe in both eyes in the traverse and sagittal planes, with the patient supine. The primary outcome was change in ONSD from pre-LP to post-LP. We calculated association of opening and closing LP pressures with changes in the pre- and post-LP ONSD measurements. RESULTS: The mean patient age was 49.0 years (SD = 37-61, range 19-67) with 21 females (72.4%) and 26 (89.7%) white American (not Hispanic or Latino). The average opening pressure and closing pressures were 20.4 cm and 13.5 cm with a difference of 6.9 cm, (95% CI 3.9-10.0 cm). Pressures between the participants with baseline ONSD measurement > 5 mm (average opening pressure = 21.3 cm) to those < 5 mm (20.2 cm) differed by 1.1 cm (95% CI - 5.7 to 8.0). Linear regression revealed no association between the sagittal, transverse, average, and change in ONSD measurements with the observed LP opening pressure, change in LP pressure, or volume of cerebral spinal fluid (CSF) drained. CONCLUSIONS: In this study of ambulatory patients undergoing rapid decreases in ICP via elective LP, we detected no acute changes in ultrasonographic measurement of the ONSD.

Hemicraniectomy for Supratentorial Primary Intracerebral Hemorrhage: A Retrospective, Propensity Score Matched Study.

BACKGROUND AND PURPOSE: Spontaneous supratentorial intracerebral hemorrhage (ICH) contributes disproportionately to stroke mortality, and randomized trials of surgical treatments for ICH have not shown benefit. Decompressive hemicraniectomy (DHC) improves functional outcome in patients with malignant middle cerebral artery ischemic stroke, but data in ICH patients is limited. We hypothesized that DHC would reduce in-hospital mortality and poor functional status (defined as modified Rankin scale ≥5) among survivors at 3 months, without increased complications. METHODS: We performed a retrospective, case-control, propensity score matched study to determine whether hemicraniectomy affected outcome in patients with spontaneous supratentorial ICH. The propensity score consisted of variables associated with outcome or predictors of hemicraniectomy. Forty-three surgical patients were matched to 43 medically managed patients on ICH location, sex, and nearest neighbor matching. Three-month functional outcomes, in-hospital mortality, and in-hospital complications were measured. RESULTS: In the medical management group, 72.1% of patients had poor outcome at 3 months compared with 37.2% who underwent hemicraniectomy (odds ratio 4.8, confidence interval 1.6-14). In-hospital mortality was 51.2% for medically managed patients and 16.3% for hemicraniectomy patients (odds ratio 8.5, confidence interval 2.0-36.8). There were no statistically significant differences in the occurrence of in-hospital complications. CONCLUSIONS: In our retrospective study of selected patients with spontaneous supratentorial ICH, DHC resulted in lower rate of in-hospital mortality and better 3-month functional status compared with medically managed patients. A randomized trial is necessary to evaluate DHC as a treatment for certain patients with spontaneous supratentorial ICH.

Coronary artery to main pulmonary artery fistulae via a Vieussens' arterial ring.

Coronary artery fistulae are rare abnormal communications between a coronary artery and a cardiac chamber or a great vessel which may shunt blood flow away from the myocardial capillary network. Vieussens arterial ring is usually described as a collateral pathway between the left anterior descending and right coronary arteries, pathology of Vieussens arterial ring are exceedingly rare. We present a case of a complex coronary artery to pulmonary artery fistula via an aneurysmal Vieussens arterial ring, with emphasis on computerized tomography and invasive angiography findings and management.

Purple urine bag syndrome in a patient with a nephrostomy tube.

Purple urine bag syndrome is an uncommon condition characterised by purple colouring of the urine in a chronically catheterised patient. Typically seen in patients with a Foley catheter in the bladder, we report an uncommon case of purple urine bag syndrome in a patient with a long-term nephrostomy tube and discuss the pathophysiology of this condition.