David Chen

Taipei Medical University | TMU · Department of Radiology

Background Poststroke cognitive impairment (PSCI) is a prevalent cause of disability in people with stroke. PSCI results from either lesion-dependent loss of cognitive function or augmentation of Alzheimer's pathology due to vascular insufficiency. The lack of prestroke cognitive assessments limits the clear understanding of the impact of PSCI on c...

Cerebrovascular reactivity (CVR) reflects the CBF change to meet different physiological demands. The reference CVR technique is PET imaging with vasodilators but is inaccessible to most patients. DSC can measure transit time to evaluate patients suspected of stroke, but the use of gadolinium may cause side-effects. Arterial spin labeling (ASL) is...

Cerebrovascular reactivity (CVR), the capacity of the brain to increase cerebral blood flow (CBF) to meet changes in physiological demand, is an important biomarker to evaluate brain health. Typically, this brain “stress test” is performed by using a medical imaging modality to measure the CBF change between two states: at baseline and after vasodi...

Cerebrovascular reactivity (CVR) reflects the capacity of the brain to meet changing physiological demands and can predict the risk of cerebrovascular diseases. CVR can be obtained by measuring the change in cerebral blood flow (CBF) during a brain stress test where CBF is altered by a vasodilator such as acetazolamide. Although the gold standard t...

Background and purpose: Phase imaging helps determine a lesion's susceptibility. However, various inhomogenous phase patterns could be observed in the serial phase images of a lesion and render image interpretation challenging. We evaluated the diagnostic accuracy of differentiating cerebral microbleeds and calcifications from phase patterns in ax...

Background Cerebrovascular reserve (CVR) may be measured by using an acetazolamide test to clinically evaluate patients with cerebrovascular disease. However, acetazolamide use may be contraindicated and/or undesirable in certain clinical settings. Purpose To predict CVR images generated from acetazolamide vasodilation with a deep learning network...

Objectives Cholinesterase inhibitors (ChEIs) are the most effective treatment for Alzheimer disease (AD), but the response to treatment varies. Vascular lesions are associated with the pathogenesis of AD, and cerebral microbleeds (CMBs) are an indicator of hemorrhagic vascular pathology, which can be detected through susceptibility-weighted magneti...

Background The hardware and software differences between MR vendors and individual sites influence the quantification of MR spectroscopy data. An analysis of a large data set may help to better understand sources of the total variance in quantified metabolite levels. Purpose To compare multisite quantitative brain MR spectroscopy data acquired in h...

Accurate and reliable quantification of brain metabolites measured in vivo using 1H magnetic resonance spectroscopy (MRS) is a topic of continued interest. Aside from differences in the basic approach to quantification, the quantification of metabolite data acquired at different sites and on different platforms poses an additional methodological ch...

Sixty-seven patients with first acute ischemic stroke onset between 3 to 7 days and 25 age- and sex- matched controls were analyzed for the performance of a resting-state functional MRI to investigate whether the functional connectivity (FC) of the motor network in acute ischemic stroke is independently associated with functional outcomes. The FC o...

Neural activity varies continually from moment to moment. Such temporal variability (TV) has been highlighted as a functionally specific brain property playing a fundamental role in cognition. We sought to investigate the mechanisms involved in TV changes between two basic behavioural states, namely having the eyes open (EO) or eyes closed (EC) in...

Objectives: The motor symptoms of Parkinson's disease (PD) vary among patients and have been categorized into 3 subtypes: tremor dominant, akinetic rigidity, and postural instability and gait disturbance (PIGD). Cerebral microbleed (CMB) is prevalent in people with PD and is associated with some nonmotor symptoms. The present study investigated th...

Purpose: No reliable imaging sign predicting cerebral hyperperfusion after intracranial arterial stenting (IAS) had been described in the literature. This study evaluated the effect of fluid-attenuated inversion recovery vascular hyperintensities (FVHs), also called hyperintense vessel sign on T2-weighted fluid-attenuated inversion recovery (T2-FL...

Effusion-based lymphoma is a rare and unique type of large B-cell lymphoma presenting in effusion without a mass lesion. It shares many clinicopathological features with primary effusion lymphoma (PEL), but is distinct from PEL by the absence of HHV8 association. Double hit lymphoma (DHL) is an aggressive B-cell lymphoma, defined by concurrent rear...

Background and purpose MR angiography (MRA) is an increasingly used evaluation method following intracranial stenting. However, the various artifacts created by the stent limit this technique. The purpose of this study was to investigate the effects of various concentrations of gadolinium contrast agent on the visibility and signal characteristics...

Background: This study uses a MRI technique, three-dimension pulse continuous arterial spin labeling (3D-PCASL), to measure the patient's cerebral blood flow (CBF) at the subacute stage of mild traumatic brain injury (MTBI) in order to analyze the relationship between cerebral blood flow and neurocognitive deficits. Objective: To provide the rel...

Introduction: Application of computed tomography for monitoring intracranial stents is limited because of stent-related artifacts. Our purpose was to evaluate the effect of gemstone spectral imaging on the intracranial stent and stent lumen. Materials and methods: In vitro, we scanned Enterprise stent phantom and a stent-cheese complex using the...

Background: Severe intracranial arterial stenosis results in more than 10% incidence of stroke and transient ischemic attack. Using undersized angioplasty with off-label closed-cell Enterprise stent may be a feasible alternative option for treating patients with intracranial atherosclerotic disease who fail dual-antiplatelet medical therapy. The r...

Aim: To elucidate the cause of cerebral hypoperfusion on the stent placement side after carotid artery stent placement (CAS) measured by pseudocontinuous arterial spin labelling (PCASL) perfusion imaging. Materials and methods: Consecutive patients with symptomatic internal carotid artery stenosis receiving CAS were included in the study. Cerebr...

Purpose To evaluate the age effect on working memory (WM) performance and functional activation after mild traumatic brain injury (MTBI). Materials and Methods This study was approved by the local research ethics committee. All participants provided written informed consent. N-back WM cerebral activation was assessed with functional magnetic resona...

Spinal dural arteriovenous fistula (SDAVF) is the most common spinal vascular malformation, however it is still rare and underdiagnosed. Magnetic resonance imaging findings such as spinal cord edema and dilated and tortuous perimedullary veins play a pivotal role in the confirmation of the diagnosis. However, spinal angiography remains the gold sta...

Purpose: To evaluate sex differences in mild traumatic brain injury (MTBI) with working memory functional magnetic resonance (MR) imaging. Materials and methods: Research ethics committee approval and patient written informed consent were obtained. Working memory brain activation patterns were assessed with functional MR imaging in 30 patients (...

To compare the frequency of microbleeds identified by susceptibility-weighted MRI (SWMRI) in patients with mild traumatic brain injury (mTBI) and normal controls, and correlate these findings with neuropsychological tests. Research ethics committee approval and patient written informed consents were obtained. One hundred eleven patients with mTBI w...

A 55-year-old man with chronic hypertension presented with acute headache and dizziness. Physical examination showed severe hypertension (210/140 mm Hg) without any neurologic sign. Brain MRI showed diffuse brain edema over the brainstem, bilateral thalami, and cerebellar hemispheres with multiple microbleeds at bilateral basal ganglia (figure 1)....

A 59-year-old man who denied a history of trauma presented with left pulsatile tinnitus and left orbital swelling for six months. Digital subtraction angiography showed a left persistent trigeminal artery (PTA) with a trigeminal artery to cavernous sinus (trigeminal-cavernous sinus) fistula and a right PTA. Transarterial detachable coil embolizatio...