Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 53
Filter
3.
SAGE Open Med Case Rep ; 12: 2050313X241257193, 2024.
Article in English | MEDLINE | ID: mdl-38864029

ABSTRACT

The management of intracranial malignancies in pregnancy poses unique challenges to the perioperative team. We describe the successful surgical management of a meningioma in a 28-year-old previously healthy patient, in her third trimester of pregnancy, who first presented with a generalised seizure. Without clear guidelines on the management of intracranial malignancies in pregnancy, a multidisciplinary approach was essential in providing a management plan for the patient's seizures and on the timing of her surgical intervention. Hormone-mediated tumour growth was a significant factor in opting for urgent surgical intervention and we discuss the current evidence linking hormones to tumour growth in pregnancy.

4.
Front Med (Lausanne) ; 11: 1385489, 2024.
Article in English | MEDLINE | ID: mdl-38938377

ABSTRACT

Introduction: Professional identity formation (PIF) is an ongoing, self-reflective process involving habits of thinking, feeling and acting like a physician and is an integral component of medical education. While qualitative work has suggested that PIF is informed by professionalism, resilience, and leadership, there is a dearth of quantitative work in this area. Multiple methods build rigor and the present study aimed to quantitatively assess the relative psychometric contributions of professionalism, resilience, and leadership constructs to informing PIF, using a latent factor analysis approach. Methods: We analyzed data from the PILLAR study, which is an online cross-sectional assessment of a pre-clinical cohort of medical students in the RCSI University of Medicine and Health Sciences, Dublin, using established and validated quantitative measures in each area of interest: PIF, professionalism, leadership and resilience. A total of 76 items, combining four validated scales, along with a selection of demographic questions, were used. The hypothesis that PIF is informed by, and correlates with, professionalism, resilience and leadership was examined by conducting a confirmatory factor analysis of a proposed three-factor higher-order model. Model estimation used Maximum Likelihood Method (MLM) with geomin rotation. The hypothesized (measurement) model was examined against an alternative (saturated) model, as well as a three-factor model. Results: Latent variable analysis from 1,311 students demonstrated that a three-factor higher-order model best fit the data; suggesting PIF is informed by professionalism, resilience, and leadership, and that these constructs are statistically distinct and account for differential aspects of PIF. This higher-order model of PIF outperformed both the saturated model and the three-factor model. The analysis of which component may be the most or least influential was inconclusive, and the overall model was not influenced by year of training. Discussion: Building upon existing conceptual contentions, our study is the first to quantitatively support the contribution of professionalism, resilience, and leadership to the development of professional identity, and to delineate the inter-relationships between PIF and these constructs. This information can be used by medical educators when designing curricula and educational strategies intended to enhance PIF. Future work should seek to assess the influence of these constructs longitudinally.

5.
Alzheimer Dis Assoc Disord ; 38(2): 160-167, 2024.
Article in English | MEDLINE | ID: mdl-38748658

ABSTRACT

INTRODUCTION: Enrolling individuals from underrepresented ethnoracial groups in aging research is often a challenge. METHODS: We sought a diverse sample of older adults from a small-town area for a longitudinal aging study. We employed an intensive community engagement approach encompassing a range of recruitment strategies. RESULTS: Over 4 years a steady trickle of individuals, 66% self-identifying as Black, signed up for study information; the proportion of those who eventually enroll in the study has been rising each year, from 68% to 94%. Community events, word-of-mouth referrals, and mailed postcards brought in the most contacts. The highest percentage of contacts who ultimately enrolled were from postcards, flyers, and word-of-mouth. Significantly more word-of-mouth referrals were endorsed by Black individuals than White and by Black men than other race/sex groups. CONCLUSIONS: We have had some success in building relationships and trust with the local community, enrolling Black study participants in a proportion equal to their representation in the target community using a variety of recruitment methods. Patience, immersion in the community, and partnerships with key community members alongside traditional advertisements, and the utilization of study participants as recruiters are critical to designing optimal, targeted, recruitment strategies.


Subject(s)
Aging , Patient Selection , Humans , Longitudinal Studies , Male , Female , Aged , Aged, 80 and over , Cohort Studies
6.
J Stroke Cerebrovasc Dis ; 33(6): 107700, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38570060

ABSTRACT

OBJECTIVES: With the rising global burden of stroke-related morbidity, and increased focus on patient-centered healthcare, patient reported outcome measures (PROMs) are increasingly used to inform healthcare decision-making. Some stroke patients with cognitive or motor impairments are unable to respond to PROMs, so proxies may respond on their behalf; the reliability of which remains unclear. The aim of the study is to update a 2010 systematic review to investigate the inter-rater reliability of proxy respondents answering PROMs for stroke patients. MATERIALS AND METHODS: Studies on the reliability of proxy respondents in stroke were searched within CINAHL, Embase, PsycInfo, and WoS databases (01/07/22, 08/07/22). Fifteen studies were included for review. ICC and k-statistic were extracted for PROMs scales and categorized as poor (0.80). Bias was assessed using the CCAT. RESULTS: Five studies reported PROMs with inter-rater reliability scores ranging from 0.80. Two studies reported activities of daily living (ADLs) scores ranging from 0.41 to 0.80 and 8 studies reported quality of life (QoL) measures with scores ranging from 0.80. Subcategories of these scales included physical (ICC/k-statistic 0.41- >0.8), cognitive (ICC/k-statistic 0.40-0.80), communication (ICC/k-statistic <0.4-0.80,) and psychological (ICC/k-statistic <0.40-0.60) measures. CONCLUSIONS: Proxy respondents are reliable sources for PROM reports on physical domains in ADLs, PROMs and QoL scales. Proxy reports for measures of communication and psychological domains had greater variability in reliability scores, ranging from poor to substantial; hence, caution should be applied when interpreting proxy reports for these domains.


Subject(s)
Activities of Daily Living , Patient Reported Outcome Measures , Proxy , Stroke , Humans , Disability Evaluation , Observer Variation , Predictive Value of Tests , Quality of Life , Reproducibility of Results , Stroke/diagnosis , Stroke/therapy , Stroke/psychology , Stroke/physiopathology , Treatment Outcome
8.
Magn Reson Med ; 89(2): 577-593, 2023 02.
Article in English | MEDLINE | ID: mdl-36161727

ABSTRACT

PURPOSE: To develop and validate a method for B 0 $$ {B}_0 $$ mapping for knee imaging using the quantitative Double-Echo in Steady-State (qDESS) exploiting the phase difference ( Δ Î¸ $$ \Delta \theta $$ ) between the two echoes acquired. Contrary to a two-gradient-echo (2-GRE) method, Δ Î¸ $$ \Delta \theta $$ depends only on the first echo time. METHODS: Bloch simulations were applied to investigate robustness to noise of the proposed methodology and all imaging studies were validated with phantoms and in vivo simultaneous bilateral knee acquisitions. Two phantoms and five healthy subjects were scanned using qDESS, water saturation shift referencing (WASSR), and multi-GRE sequences. Δ B 0 $$ \Delta {B}_0 $$ maps were calculated with the qDESS and the 2-GRE methods and compared against those obtained with WASSR. The comparison was quantitatively assessed exploiting pixel-wise difference maps, Bland-Altman (BA) analysis, and Lin's concordance coefficient ( ρ c $$ {\rho}_c $$ ). For in vivo subjects, the comparison was assessed in cartilage using average values in six subregions. RESULTS: The proposed method for measuring Δ B 0 $$ \Delta {B}_0 $$ inhomogeneities from a qDESS acquisition provided Δ B 0 $$ \Delta {B}_0 $$ maps that were in good agreement with those obtained using WASSR. Δ B 0 $$ \Delta {B}_0 $$ ρ c $$ {\rho}_c $$ values were ≥ $$ \ge $$ 0.98 and 0.90 in phantoms and in vivo, respectively. The agreement between qDESS and WASSR was comparable to that of a 2-GRE method. CONCLUSION: The proposed method may allow B0 correction for qDESS T 2 $$ {T}_2 $$ mapping using an inherently co-registered Δ B 0 $$ \Delta {B}_0 $$ map without requiring an additional B0 measurement sequence. More generally, the method may help shorten knee imaging protocols that require an auxiliary Δ B 0 $$ \Delta {B}_0 $$ map by exploiting a qDESS acquisition that also provides T 2 $$ {T}_2 $$ measurements and high-quality morphological imaging.


Subject(s)
Knee , Magnetic Resonance Imaging , Humans , Magnetic Resonance Imaging/methods , Phantoms, Imaging , Knee/diagnostic imaging , Knee Joint/diagnostic imaging , Water
9.
J Magn Reson Imaging ; 58(3): 951-962, 2023 09.
Article in English | MEDLINE | ID: mdl-36583628

ABSTRACT

BACKGROUND: Diffusion-weighted imaging (DWI) may allow for breast cancer screening MRI without a contrast injection. Multishot methods improve prone DWI of the breasts but face different challenges in the supine position. PURPOSE: To establish a multishot DWI (msDWI) protocol for supine breast MRI and to evaluate the performance of supine vs. prone msDWI. STUDY TYPE: Prospective. POPULATION: Protocol optimization: 10 healthy women (ages 22-56), supine vs. prone: 24 healthy women (ages 22-62) and five women (ages 29-61) with breast tumors. FIELD STRENGTH/SEQUENCE: 3-T, protocol optimization msDWI: free-breathing (FB) 2-shots, FB 4-shots, respiratory-triggered (RT) 2-shots, RT 4-shots, supine vs. prone: RT 4-shot msDWI, T2-weighted fast-spin echo. ASSESSMENT: Protocol optimization and supine vs. prone: three observers performed an image quality assessment of sharpness, aliasing, distortion (vs. T2), perceived SNR, and overall image quality (scale of 1-5). Apparent diffusion coefficients (ADCs) in fibroglandular tissue (FGT) and breast tumors were measured. STATISTICAL TESTS: Effect of study variables on dichotomized ratings (4/5 vs. 1/2/3) and FGT ADCs were assessed with mixed-effects logistic regression. Interobserver agreement utilized Gwet's agreement coefficient (AC). Lesion ADCs were assessed by Bland-Altman analysis and concordance correlation (ρc ). P value <0.05 was considered statistically significant. RESULTS: Protocol optimization: 4-shots significantly improved sharpness and distortion; RT significantly improved sharpness, aliasing, perceived SNR, and overall image quality. FGT ADCs were not significantly different between shots (P = 0.812), FB vs. RT (P = 0.591), or side (P = 0.574). Supine vs. prone: supine images were rated significantly higher for sharpness, aliasing, and overall image quality. FGT ADCs were significantly higher supine; lesion ADCs were highly correlated (ρc  = 0.92). DATA CONCLUSION: Based on image quality, supine msDWI outperformed prone msDWI. Lesion ADCs were highly correlated between the two positions, while FGT ADCs were higher in the supine position. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 1.


Subject(s)
Breast Neoplasms , Diffusion Magnetic Resonance Imaging , Humans , Female , Prospective Studies , Prone Position , Diffusion Magnetic Resonance Imaging/methods , Magnetic Resonance Imaging , Reproducibility of Results , Breast Neoplasms/diagnostic imaging , Echo-Planar Imaging/methods
10.
Med Teach ; 45(1): 40-48, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36214365

ABSTRACT

BACKGROUND: Medical students have reported high prevalence of mental health difficulties and burnout. However, there are limited investigations examining the association between resilience and these difficulties. We investigated: (1) depression, anxiety, personal and professional burnout, and comorbidity; (2) demographic and education characteristics associated with these outcomes; (3) the association between resilience and these outcomes; and (4) whether these results were attributable to sampling bias. METHODS: Participants were n = 521 medical students from RCSI University of Medicine and Health Sciences. Outcomes were measured using validated scales. We report descriptive statistics, and risk factors for the difficulties were investigated using generalized linear modelling. RESULTS: One-in-three students reported incidence of depression or anxiety (24.5% co-morbidity). 8.9% of students reported all four difficulties. Difficulties were more common in female students and those in middle years of the programme. Resilience was negatively correlated with all outcomes and stable across demographic and educational variables. Weighting the data for sampling bias did not affect these results. CONCLUSIONS: Our results emphasise the high incidence of depression, anxiety, burnout, and comorbidity in students. We advocate for further investigation into the role of resilience as a modifiable factor that may ameliorate the incidence of depression, anxiety, and burnout in medical students.


Subject(s)
Burnout, Professional , Students, Medical , Humans , Female , Students, Medical/psychology , Mental Health , Cross-Sectional Studies , Depression/epidemiology , Anxiety/epidemiology , Burnout, Professional/epidemiology
12.
Psychol Aging ; 36(2): 252-267, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33539151

ABSTRACT

The consistently observed age-accompanied diminution in mind-wandering stands seemingly opposed to accounts that present mind-wandering as a failure of executive control. This study examined the impact of aging on the frequency and phenomenology of mind-wandering and investigated distinct variables mediating age-related differences in unintentional and intentional mind-wandering. Thirty-four younger and 34 healthy older adults completed a neuropsychological test battery and contrast change detection task embedded with experience sampling probes asking participants to discriminate the nature of their thoughts. Results revealed age-related decreases in unintentional and intentional mind-wandering, but equivalent task accuracy. Parallel mediations demonstrated that older adults reduced their unintentional mind-wandering through having less anxiety and greater task engagement than younger adults. Despite the evidence of age-related decline on cognitive function tests, neither executive function nor task demand variables further contributed to the model. Our results adjudicate between competing theories, highlighting the roles of affective and motivational factors in unintentional mind-wandering. Intentional mind-wandering showed no significant associations with the neuropsychological measures; however, intentional mind-wandering was associated with more false alarms, which was mediated by greater reaction time variability (RTV). In the context of the exploitation/exploration framework, we suggest that younger adults were more inclined to intentionally mind-wander, indexed by increased RTV, while preserving comparable performance accuracy to older adults. Conversely, older adults exploited greater task focus, marked by reduced RTV, with less bias toward, or resources for, exploration of the mind-wandering space. Therefore, dispositional and strategic factors should be considered in future investigations of mind-wandering across the lifespan. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Subject(s)
Aging/psychology , Attention/physiology , Adolescent , Adult , Aged , Executive Function/physiology , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Reaction Time/physiology , Young Adult
14.
J Magn Reson Imaging ; 53(5): 1594-1605, 2021 05.
Article in English | MEDLINE | ID: mdl-33382171

ABSTRACT

The image quality limitations of echo-planar diffusion-weighted imaging (DWI) are an obstacle to its widespread adoption in the breast. Steady-state DWI is an alternative DWI method with more robust image quality but its contrast for imaging breast cancer is not well-understood. The aim of this study was to develop and evaluate diffusion-weighted double-echo steady-state imaging with a three-dimensional cones trajectory (DW-DESS-Cones) as an alternative to conventional DWI for non-contrast-enhanced MRI in the breast. This prospective study included 28 women undergoing clinically indicated breast MRI and six asymptomatic volunteers. In vivo studies were performed at 3 T and included DW-DESS-Cones, DW-DESS-Cartesian, DWI, and CE-MRI acquisitions. Phantom experiments (diffusion phantom, High Precision Devices) and simulations were performed to establish framework for contrast of DW-DESS-Cones in comparison to DWI in the breast. Motion artifacts of DW-DESS-Cones were measured with artifact-to-noise ratio in volunteers and patients. Lesion-to-fibroglandular tissue signal ratios were measured, lesions were categorized as hyperintense or hypointense, and an image quality observer study was performed in DW-DESS-Cones and DWI in patients. Effect of DW-DESS-Cones method on motion artifacts was tested by mixed-effects generalized linear model. Effect of DW-DESS-Cones on signal in phantom was tested by quadratic regression. Correlation was calculated between DW-DESS-Cones and DWI lesion-to-fibroglandular tissue signal ratios. Inter-observer agreement was assessed with Gwet's AC. Simulations predicted hyperintensity of lesions with DW-DESS-Cones but at a 3% to 67% lower degree than with DWI. Motion artifacts were reduced with DW-DESS-Cones versus DW-DESS-Cartesian (p < 0.05). Lesion-to-fibroglandular tissue signal ratios were not correlated between DW-DESS-Cones and DWI (r = 0.25, p = 0.38). Concordant hyperintensity/hypointensity was observed between DW-DESS-Cones and DWI in 11/14 lesions. DW-DESS-Cones improved sharpness, distortion, and overall image quality versus DWI. DW-DESS-Cones may be able to eliminate motion artifacts in the breast allowing for investigation of higher degrees of steady-state diffusion weighting. Malignant breast lesions in DW-DESS-Cones demonstrated hyperintensity with respect to surrounding tissue without an injection of contrast. LEVEL OF EVIDENCE: 2. TECHNICAL EFFICACY STAGE: 1.


Subject(s)
Breast Neoplasms , Diffusion Magnetic Resonance Imaging , Breast/diagnostic imaging , Breast Neoplasms/diagnostic imaging , Echo-Planar Imaging , Female , Humans , Magnetic Resonance Imaging , Prospective Studies
15.
Magn Reson Med ; 85(2): 709-720, 2021 02.
Article in English | MEDLINE | ID: mdl-32783339

ABSTRACT

PURPOSE: To accelerate and improve multishot diffusion-weighted MRI reconstruction using deep learning. METHODS: An unrolled pipeline containing recurrences of model-based gradient updates and neural networks was introduced for accelerating multishot DWI reconstruction with shot-to-shot phase correction. The network was trained to predict results of jointly reconstructed multidirection data using single-direction data as input. In vivo brain and breast experiments were performed for evaluation. RESULTS: The proposed method achieves a reconstruction time of 0.1 second per image, over 100-fold faster than a shot locally low-rank reconstruction. The resultant image quality is comparable to the target from the joint reconstruction with a peak signal-to-noise ratio of 35.3 dB, a normalized root-mean-square error of 0.0177, and a structural similarity index of 0.944. The proposed method also improves upon the locally low-rank reconstruction (2.9 dB higher peak signal-to-noise ratio, 29% lower normalized root-mean-square error, and 0.037 higher structural similarity index). With training data from the brain, this method also generalizes well to breast diffusion-weighted imaging, and fine-tuning further reduces aliasing artifacts. CONCLUSION: A proposed data-driven approach enables almost real-time reconstruction with improved image quality, which improves the feasibility of multishot DWI in a wide range of clinical and neuroscientific studies.


Subject(s)
Algorithms , Diffusion Magnetic Resonance Imaging , Artifacts , Brain/diagnostic imaging , Image Processing, Computer-Assisted , Reproducibility of Results
16.
J Magn Reson Imaging ; 53(3): 807-817, 2021 03.
Article in English | MEDLINE | ID: mdl-33067849

ABSTRACT

BACKGROUND: Diffusion-weighted imaging (DWI) has shown promise to screen for breast cancer without a contrast injection, but image distortion and low spatial resolution limit standard single-shot DWI. Multishot DWI methods address these limitations but introduce shot-to-shot phase variations requiring correction during reconstruction. PURPOSE: To investigate the performance of two multishot DWI reconstruction methods, multiplexed sensitivity encoding (MUSE) and shot locally low-rank (shot-LLR), compared to single-shot DWI in the breast. STUDY TYPE: Prospective. POPULATION: A total of 45 women who consented to have multishot DWI added to a clinically indicated breast MRI. FIELD STRENGTH/SEQUENCES: Single-shot DWI reconstructed by parallel imaging, multishot DWI with four or eight shots reconstructed by MUSE and shot-LLR, 3D T2 -weighted imaging, and contrast-enhanced MRI at 3T. ASSESSMENT: Three blinded observers scored images for 1) general image quality (perceived signal-to-noise ratio [SNR], ghosting, distortion), 2) lesion features (discernment and morphology), and 3) perceived resolution. Apparent diffusion coefficient (ADC) of the lesion was also measured and compared between methods. STATISTICAL TESTS: Image quality features and perceived resolution were assessed with a mixed-effects logistic regression. Agreement among observers was estimated with a Krippendorf's alpha using linear weighting. Lesion feature ratings were visualized using histograms, and correlation coefficients of lesion ADC between different methods were calculated. RESULTS: MUSE and shot-LLR images were rated to have significantly better perceived resolution (P < 0.001), higher SNR (P < 0.005), and a lower level of distortion (P < 0.05) with respect to single-shot DWI. Shot-LLR showed reduced ghosting artifacts with respect to both MUSE (P < 0.001) and single-shot DWI (P < 0.001). Eight-shot DWI had improved perceived SNR and perceived resolution with respect to four-shot DWI (P < 0.005). DATA CONCLUSION: Multishot DWI enables increased resolution and improved image quality with respect to single-shot DWI in the breast. Shot-LLR reconstructs multishot DWI with minimal ghosting artifacts. The improvement of multishot DWI in image quality increases with an increased number of shots. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 2.


Subject(s)
Diffusion Magnetic Resonance Imaging , Echo-Planar Imaging , Artifacts , Female , Humans , Magnetic Resonance Imaging , Prospective Studies , Reproducibility of Results
17.
Neurosurgery ; 88(1): 165-173, 2020 12 15.
Article in English | MEDLINE | ID: mdl-32985669

ABSTRACT

BACKGROUND: Recent advances in methods used for deep brain stimulation (DBS) include subthalamic nucleus electrode implantation in the "asleep" patient without the traditional use of microelectrode recordings or intraoperative test stimulation. OBJECTIVE: To examine the clinical outcome of patients who have undergone "asleep" DBS for the treatment of Parkinson disease using robot-assisted electrode delivery. METHODS: This is a retrospective review of clinical outcomes of 152 consecutive patients. Their outcomes at 1 yr postimplantation are reported; these include Unified Parkinson's Disease Rating Scale (UPDRS) assessment, Tinetti Mobility Test, Parkinson's Disease Questionnaire (PDQ)-39 quality of life assessment, Mattis Dementia Rating Scale, Beck Depression Inventory, and Beck Anxiety. We also report on a new parietal trajectory for electrode implantation. RESULTS: A total of 152 patients underwent assessment at 1 yr. UPDRS III improved from 39 to 20.5 (47%, P < .001). The total UPDRS score improved from 67.6 to 36.4 (46%, P < .001). UPDRS II scores improved from 18.9 to 10.5 (44%, P < .001) and UPDRS IV scores improved from 7.1 to 3.6 (49%, P < .001). There was a significant reduction in levodopa equivalent daily dose after surgery (mean: 35%, P < .001). PDQ-39 summary index improved by a mean of 7.1 points. There was no significant difference found in clinical outcomes between the frontal and parietal approaches. CONCLUSION: "Asleep" robot-assisted DBS of the subthalamic nucleus demonstrates comparable outcomes with traditional techniques in the treatment of Parkinson disease.


Subject(s)
Deep Brain Stimulation/methods , Neurosurgical Procedures/methods , Parkinson Disease/therapy , Robotic Surgical Procedures/methods , Aged , Electrodes, Implanted , Female , Humans , Male , Middle Aged , Quality of Life , Retrospective Studies , Subthalamic Nucleus/physiology , Treatment Outcome
18.
Oper Neurosurg (Hagerstown) ; 19(5): 530-538, 2020 10 15.
Article in English | MEDLINE | ID: mdl-32629477

ABSTRACT

BACKGROUND: Robotics in neurosurgery has demonstrated widening indications and rapid growth in recent years. Robotic precision and reproducibility are especially pertinent to the field of functional neurosurgery. Deep brain stimulation (DBS) requires accurate placement of electrodes in order to maximize efficacy and minimize side effects. In addition, asleep techniques demand clear target visualization and immediate on-table verification of accuracy. OBJECTIVE: To describe the surgical technique of asleep DBS surgery using the Neuro|MateTM Robot (Renishaw plc, Wotton-under-Edge, United Kingdom) and examine the accuracy of DBS lead placement in the subthalamic nucleus (STN) for the treatment of movement disorders. METHODS: A single-center retrospective review of 113 patients who underwent bilateral STN/Zona Incerta electrode placement was performed. Accuracy of implantation was assessed using 5 measurements, Euclidian distance, radial error, depth error, angular error, and shift error. RESULTS: A total of 226 planned vs actual electrode placements were analyzed. The mean 3-dimensional vector error calculated for 226 trajectories was 0.78 +/- 0.37 mm. The mean radial displacement off planned trajectory was 0.6 +/- 0.33 mm. The mean depth error, angular error, and shift error was 0.4 +/- 0.35 mm, 0.4 degrees, and 0.3 mm, respectively. CONCLUSION: This report details our institution's method for DBS lead placement in patients under general anaesthesia using anatomical targeting without microelectrode recordings or intraoperative test stimulation for the treatment of movement disorders. This is the largest reported dataset of accuracy results in DBS surgery performed asleep. This novel robot-assisted operative technique results in sub-millimeter accuracy in DBS electrode placement.


Subject(s)
Deep Brain Stimulation , Parkinson Disease , Robotics , Electrodes, Implanted , Humans , Parkinson Disease/therapy , Reproducibility of Results , Retrospective Studies
19.
Magn Reson Med ; 84(1): 170-181, 2020 07.
Article in English | MEDLINE | ID: mdl-31782557

ABSTRACT

PURPOSE: To develop a near-silent and distortionless DWI (sd-DWI) sequence using magnetization-prepared rotating ultrafast imaging sequence. METHODS: A rotating ultrafast imaging sequence was modified with driven-equilibrium diffusion preparation, including eddy-current compensation methods. To compensate for the T1 recovery during readout, a phase-cycling method was used. Both compensation methods were validated in phantoms. The optimized sequence was compared with an EPI diffusion sequence for image distortion, contrast, ADC, and acoustic noise level in phantoms. The sequence was evaluated in 1 brain volunteer, 5 prostate volunteers, and 10 pediatric patients with joint diseases. RESULTS: Combination of several eddy-current compensation methods reduced the artifact to an acceptable level. Phase cycling reduced T1 recovery contamination during readout. In phantom scans, the optimized sequence generated similar image contrast to the EPI diffusion sequence, and ADC maps between the sequences were comparable; sd-DWI had significantly lower acoustic noise (P < .05). In vivo brain scan showed reduced image distortion in sd-DWI compared with the EPI diffusion, although residual motion artifact remains due to brain pulsation. The prostate scans showed that sd-DWI can provide similar ADC compared with EPI diffusion, with no image distortion. Patient scans showed that the sequence can clearly depict joint lesions. CONCLUSION: An sd-DWI sequence was developed and optimized. Compared with conventional EPI diffusion, sd-DWI provided similar diffusion contrast, accurate ADC measurement, improved image quality, and minimal ambient scanning noise. The sequence showed the ability to obtain in vivo diffusion contrast in relatively motion-free body regions, such as prostate and joint.


Subject(s)
Diffusion Magnetic Resonance Imaging , Echo-Planar Imaging , Artifacts , Brain/diagnostic imaging , Child , Humans , Male , Phantoms, Imaging , Reproducibility of Results
20.
Magn Reson Med ; 81(2): 1181-1190, 2019 02.
Article in English | MEDLINE | ID: mdl-30346058

ABSTRACT

PURPOSE: The goal of this work is to propose a motion robust reconstruction method for diffusion-weighted MRI that resolves shot-to-shot phase mismatches without using phase estimation. METHODS: Assuming that shot-to-shot phase variations are slowly varying, spatial-shot matrices can be formed using a local group of pixels to form columns, in which each column is from a different shot (excitation). A convex model with a locally low-rank constraint on the spatial-shot matrices is proposed. In vivo brain and breast experiments were performed to evaluate the performance of the proposed method. RESULTS: The proposed method shows significant benefits when the motion is severe, such as for breast imaging. Furthermore, the resulting images can be used for reliable phase estimation in the context of phase-estimation-based methods to achieve even higher image quality. CONCLUSION: We introduced the shot-locally low-rank method, a reconstruction technique for multishot diffusion-weighted MRI without explicit phase estimation. In addition, its motion robustness can be beneficial to neuroimaging and body imaging.


Subject(s)
Brain/diagnostic imaging , Breast/diagnostic imaging , Image Processing, Computer-Assisted/methods , Algorithms , Artifacts , Diffusion Magnetic Resonance Imaging , Diffusion Tensor Imaging , Fourier Analysis , Healthy Volunteers , Humans , Image Interpretation, Computer-Assisted/methods , Motion , Reproducibility of Results
SELECTION OF CITATIONS
SEARCH DETAIL
...