Lesion Mapping Research Articles

Recent Advances in DNA Lesion Mapping and Repair Mechanisms.

Recognition and repair of DNA lesions are critical for cell survival. Herein, we highlight recent advances in the sequencing, repair mechanisms, and biological consequences of DNA lesions presented at the 2022 Fall American Chemical Society meeting.

Brain Lesions Associated with Communication-Related Quality of Life Following Surgical Removal of Primary Left-Hemisphere Tumours

ABSTRACT Background Long-term health-related quality of life (HRQoL) is an important consideration in planning treatment for individuals with brain tumours. Aim The current study examined relationships between HRQoL and anatomical location of the lesion in patients 6-24 months post-surgery. Methods Following left-hemisphere tumour resection, 37 individuals underwent behavioural testing and MRI. A principal component analysis across 10 HRQoL measures identified two components explaining ~62% of the variance: a communication-related and a mood-related component. Three lesion maps were generated per participant capturing (1) the primary resection, (2) the resection plus residual tumour, oedema, and peri-resection treatment effect (resection+), and (3) residual tumour, oedema, and peri-resection treatment effect alone (residual). Relationships between HRQoL components and lesion maps were examined using voxel-wise lesion symptom-mapping as well as general linear models predicting tract- and voxel-wise disconnection severities. Results Communication-related quality of life was significantly associated with lesions comprising both the resection+ and residual tumour in the left medial inferior parietal lobe. Voxel-wise analyses of white matter disconnection severities revealed significant associations between communication-related quality of life and thalamostriatal fibres for the residual tumour lesions. None of the analyses involving mood-related quality of life or the primary resection lesion maps were significant. Conclusions The findings highlight the role of the residual tumour, oedema, and peri-resection treatment effects and associated white matter disconnection in communication-related quality of life following treatment.

Green Tattoo Pre-Operative Renal Embolization for Robotic-Assisted and Laparoscopic Partial Nephrectomy: A Practical Proof of a New Technique.

(1) Background: Our aim is to describe a new mixed indocyanine-non-adhesive liquid embolic agent (Onyx-18) pre-operative renal embolization technique for assisted-robotic and laparoscopic partial nephrectomy with near-infra-red fluorescence imaging. (2) Methods: Thirteen patients with biopsy-proven renal tumors underwent pre-operative mixed indocyanine-ethylene vinyl alcohol (EVOH) embolization (Green-embo) between June 2021 and August 2022. All pre-operative embolizations were performed with a super selective stop-flow technique using a balloon microcatheter to deliver an indocyanine-EVOH mixture into tertiary order arterial branch feeders and the intra-lesional vascular supply. Efficacy (evaluated as complete embolization, correct tumor mapping on infra-red fluorescence imaging and clamp-off surgery) and safety (evaluated as complication rate and functional outcomes) were primary goals. Clinical and pathological data were also collected. (3) Results: Two male and eleven female patients (mean age 72 years) received pre-operative Green-embo. The median tumor size was 29 mm (range 15-50 mm). Histopathology identified renal cell carcinoma (RCC) in 9 of the 13 (69%) patients, oncocytoma in 3 of the 13 (23%) patients and sarcomatoid RCC in 1 of the 13 (8%) patients. Lesions were equally distributed between polar, meso-renal, endo- and exophytic locations. Complete embolization was achieved in all the procedures. A correct green mapping was identified during all infra-red fluorescence imaging. All patients were discharged on the second day after the surgery. The median blood loss was 145 cc (10-300 cc). No significant differences were observed in serum creatinine levels before and after the embolization procedures. (4) Conclusions: The Green-tattoo technique based on a mixed indocyanine-non-adhesive liquid embolic agent (Onyx-18) is a safe and effective pre-operative embolization technique. The main advantages are the excellent lesion mapping for fluorescence imaging, reduction in surgical time, and definitive, complete and immediate tumor devascularization based on the deep Onyx-18 penetration, leading to a very low intra-operative blood loss.

7585 A Systematic Approach to Endometriosis Lesion Mapping and Radical Excision

<h3>Study Objective</h3> To illustrate a systematic approach to laparoscopic endometriosis lesion mapping and radical wide field excision. Significant variation exists regarding the optimal approach to surgical management of endometriosis with attempts for standardization being fairly recent. We hereby contribute to these efforts by presenting our approach to radical, wide-field endometriosis excision in our institution. <h3>Design</h3> Edited surgical video demonstrating laparoscopic radical wide field endometriosis excision. <h3>Setting</h3> Academically affiliated community hospital. <h3>Patients or Participants</h3> Surgical videos of multiple surgical cases from our practice <h3>Interventions</h3> Laparoscopic radical wide field excision of endometriosiss. <h3>Measurements and Main Results</h3> As illustrated in this video, important considerations are the non-contact, mm by mm dissection along the avascular planes, use of the perirectal tissue fat as an insulator and landmark for dissection, as well as the deliberate use of rectal and vaginal probes in order to delineate anatomy and optimize dissection geometry. <h3>Conclusion</h3> With a systematic approach to radical wide field excision of endometriosis, both in high and low ASRM stage disease, via a lateral to medial approach and clockwise progression from the left pelvic brim to the left pelvic sidewall and so on, virtually all cases will be completed safely and efficiently.

Involvement of Thalamocortical Networks in Patients With Poststroke Thalamic Aphasia.

Theories assume that thalamic stroke may cause aphasia because of dysfunction in connected cortical networks. This takes into account that brain functions are organized in distributed networks, and in turn, localized damage may result in a network disorder such as thalamic aphasia. With this study, we investigate whether the integration of the thalamus into specific thalamocortical networks underlies symptoms after thalamic stroke. We hypothesize that thalamic lesions in patients with language impairments are functionally connected to cortical networks for language and cognition. We combined nonparametric lesion mapping methods in a retrospective cohort of patients with acute or subacute first-ever thalamic stroke. A relationship between lesion location and language impairments was assessed using nonparametric voxel-based lesion-symptom mapping. This method reveals regions more frequently damaged in patients with compared with those without a symptom of interest. To test whether these symptoms are linked to a common thalamocortical network, we additionally performed lesion-network-symptom mapping. This method uses normative connectome data from resting-state fMRI of healthy participants (n = 65) for functional connectivity analyses, with lesion sites serving as seeds. Resulting lesion-dependent network connectivity of patients with language impairments was compared with those with motor and sensory deficits as baseline. A total of 101 patients (mean [SD] age 64.1 [14.6] years, 57 left, 42 right, and 2 bilateral lesions) were included in the study. Voxel-based lesion-symptom mapping showed an association of language impairments with damage to left mediodorsal thalamic nucleus lesions. Lesion-network-symptom mapping revealed that language compared with sensory deficits were associated with higher normative lesion-dependent network connectivity to left frontotemporal language networks and bilateral prefrontal, insulo-opercular, midline cingular, and parietal domain-general networks. Lesions related to motor and sensory deficits showed higher lesion-dependent network connectivity within the sensorimotor network spanning prefrontal, precentral, and postcentral cortices. Thalamic aphasia relates to lesions in the left mediodorsal thalamic nucleus and to functionally connected left cortical language and bilateral cortical networks for cognitive control. This suggests that dysfunction in thalamocortical networks contributes to thalamic aphasia. We propose that inefficient integration between otherwise undamaged domain-general and language networks may cause thalamic aphasia.

PSMA PET/CT–Based Atlas for Prostatic Bed Recurrence of Prostate Cancer after Radical Prostatectomy: Clinical Implications for Salvage Radiation Therapy

<h3>Purpose/Objective(s)</h3> Postoperative radiotherapy (RT) to the prostate bed (PB) is a potentially curative treatment after radical prostatectomy (RP). The PB target definition follows contouring guidelines mostly based on expert consensus, and does not account for anatomical patterns of recurrence on more contemporary imaging. Herein, we analyze the patterns of recurrence in the PB of prostate cancer (PCa) patients with biochemical recurrence after RP using ⁶⁸Ga-PSMA-11 PET/CT (PSMA PET). We also evaluate patterns of PSMA PET recurrence in relation to the RTOG-based clinical target volumes (CTVs) definition. <h3>Materials/Methods</h3> Patients with biochemically recurrent PCa after RP, without previous history of PB RT, were retrospectively included if their PSMA PET showed evidence of recurrence in the PB. Two nuclear medicine physicians manually delineated the PB lesions on the CT images of the PSMA PET/CT. Four radiation oncologists, masked to the PSMA PET component of the PET/CT study and to the PSMA-based delineations, contoured the RTOG-based CTVs on the same CT. Three-dimensional heat maps of the PSMA PET-positive PB lesions were generated to visually depict patterns of PSMA PET recurrences. The coverage of the PSMA PET recurrence by the RTOG-based CTVs was categorized in consensus by a nuclear medicine physician and a radiation oncologist as follows: fully within, partly covered or fully outside. <h3>Results</h3> 2,415 PSMA PET scans performed at UCLA between 11/2016 and 11/2020 were screened for inclusion criteria. 230/2,415 (10%) scans of patients with prostate bed recurrence on PSMA PET were included. 127 (55%) patients had miTrN0M0, 30 (13%) miTrN1M0, 34 (15%) miTrN0M1, and 39 (17%) miTrN1M. In the miTrN0M0 cohort, PSMA-positive recurrences were fully covered by the CTV in 68/127 (54%) of the patients, partly covered in 43/127 (34%), and fully outside in 16/127 (13%). Lesions with partial coverage or fully outside the CTV were located at posterior border in 21/127 (53%), postero-lateral in 15/127 (25%), postero-inferior in 2/127 (3%), anterior in 1/127 (2%), antero-inferior in 1/127 (2%), superior in 1/127 (2%) and inferior in 8/127 (14%) of patients. The median (IQR) PSA levels were 1.11 ng/mL (1.7), 1.10 ng/mL (2.17) and 0.84 ng/mL (0.49), and the volumes of PSMA PET recurrences were 0.57cc (0.77), 1.01cc (1.71) and 0.68cc (0.59) in patients with recurrences fully within, partially covered and fully outside the CTV, respectively. <h3>Conclusion</h3> To our knowledge, this is the largest study with a detailed mapping of recurrences in the prostate bed using PSMA PET imaging. In patients with recurrences exclusive to the prostate bed (miTrN0M0), the RTOG contouring guidelines showed suboptimal coverage of the disease in 46% of patients. Our study suggests that PSMA PET can be an invaluable tool for postoperative radiotherapy planning and should be incorporated into a redefinition of RT contouring guidelines.

Skin Lesion Classification on Imbalanced Data Using Deep Learning with Soft Attention.

Today, the rapid development of industrial zones leads to an increased incidence of skin diseases because of polluted air. According to a report by the American Cancer Society, it is estimated that in 2022 there will be about 100,000 people suffering from skin cancer and more than 7600 of these people will not survive. In the context that doctors at provincial hospitals and health facilities are overloaded, doctors at lower levels lack experience, and having a tool to support doctors in the process of diagnosing skin diseases quickly and accurately is essential. Along with the strong development of artificial intelligence technologies, many solutions to support the diagnosis of skin diseases have been researched and developed. In this paper, a combination of one Deep Learning model (DenseNet, InceptionNet, ResNet, etc) with Soft-Attention, which unsupervisedly extract a heat map of main skin lesions. Furthermore, personal information including age and gender are also used. It is worth noting that a new loss function that takes into account the data imbalance is also proposed. Experimental results on data set HAM10000 show that using InceptionResNetV2 with Soft-Attention and the new loss function gives 90 percent accuracy, mean of precision, F1-score, recall, and AUC of 0.81, 0.81, 0.82, and 0.99, respectively. Besides, using MobileNetV3Large combined with Soft-Attention and the new loss function, even though the number of parameters is 11 times less and the number of hidden layers is 4 times less, it achieves an accuracy of 0.86 and 30 times faster diagnosis than InceptionResNetV2.

A precise language network revealed by the independent component-based lesion mapping in post-stroke aphasia.

Brain lesion mapping studies have provided the strongest evidence regarding the neural basis of cognition. However, it remained a problem to identify symptom-specific brain networks accounting for observed clinical and neuroanatomical heterogeneity. Independent component analysis (ICA) is a statistical method that decomposes mixed signals into multiple independent components. We aimed to solve this issue by proposing an independent component-based lesion mapping (ICLM) method to identify the language network in patients with moderate to severe post-stroke aphasia. Lesions were first extracted from 49 patients with post-stroke aphasia as masks applied to fMRI data in a cohort of healthy participants to calculate the functional connectivity (FC) within the masks and non-mask brain voxels. ICA was further performed on a reformatted FC matrix to extract multiple independent networks. Specifically, we found that one of the lesion-related independent components (ICs) highly resembled classical language networks. Moreover, the damaged level within the language-related lesioned network is strongly associated with language deficits, including aphasia quotient, naming, and auditory comprehension scores. In comparison, none of the other two traditional lesion mapping methods found any regions responsible for language dysfunction. The language-related lesioned network extracted with the ICLM method showed high specificity in detecting aphasia symptoms compared with the performance of resting ICs and classical language networks. In total, we detected a precise language network in patients with aphasia and proved its efficiency in the relationship with language symptoms. In general, our ICLM could successfully identify multiple lesion-related networks from complicated brain diseases, and be used as an effective tool to study brain-behavior relationships and provide potential biomarkers of particular clinical behavioral deficits.

Distribution Pattern Analysis of Cortical Brain Infarcts on Diffusion-Weighted Magnetic Resonance Imaging: A Hypothesis-Generating Approach to the Burden of Silent Embolic Stroke.

Background In patients with covert cerebrovascular disease or proximal source of embolism, embolic silent brain infarction may precede major stroke events. Therefore, characterization of particularly cortical silent brain infarction is essential for identifying affected patients and commencing adequate secondary prevention. This study aimed to investigate differences in the distribution pattern of cortical ischemic stroke lesions to assess potential predilection sites of cortical silent brain infarction. Methods and Results We prospectively included all consecutive patients with stroke presenting from January 1 to December 31, 2018. Diffusion-weighted imaging lesions were used to generate voxel-based lesion maps and assigned to atlas-based cortical regions of interest in middle cerebral artery territories. Each region-of-interest lesion frequency was related to the respective region-of-interest volume to identify frequently affected and underrepresented cerebral cortex areas. Diffusion-weighted imaging data for voxel-based lesion maps were available in 334 out of 633 patients. Primary analysis revealed that small- (<0.24 cc) and medium-sized (0.24-2640 cc) lesions distributed predominantly along regions associated with sensorimotor or language function. Detailed analysis within middle cerebral artery territories showed an approximated frequency of missed cortical stroke lesions of up to 67% in the right and 69% in the left hemisphere. In particular, the frontal, temporal, and occipital cortices were underrepresented. Larger lesion size and areas associated with higher cortical function led to hospital admission. Conclusions Cortical brain infarcts in hospitalized patients are not dispersed equally but are predominantly located in brain structures associated with motor control and sensory and language function. Matching underrepresented cerebral cortex regions to symptoms not yet associated with stroke warrants further exploration.

Determinants of functioning and health-related quality of life after vestibular stroke.

BackgroundStroke accounts for 5–10% of all presentations with acute vertigo and dizziness. The objective of the current study was to examine determinants of long-term functioning and health-related quality of life (HRQoL) in a patient cohort with vestibular stroke.MethodsThirty-six patients (mean age: 66.1 years, 39% female) with an MRI-proven vestibular stroke were followed prospectively (mean time: 30.2 months) in the context of the EMVERT (EMergency VERTigo) cohort study at the Ludwig-Maximilians Universität, Munich. The following scores were obtained once in the acute stage (<24 h of symptom onset) and once during long-term follow-up (preferably >1 year after stroke): European Quality of Life Scale-five dimensions-five levels questionnaire (EQ-5D-5L) and Visual Analog Scale (EQ-VAS) for HRQoL, Dizziness Handicap Inventory (DHI) for symptom severity, and modified Rankin Scale (mRS) for general functioning and disability. Anxiety state and trait were evaluated by STAI-S/STAI-T, and depression was evaluated by the Patient Health Questionnaire-9 (PHQ-9). Voxel-based lesion mapping was applied in normalized MRIs to analyze stroke volume and localization. Multiple linear regression models were calculated to determine predictors of functional outcome (DHI, EQ-VAS at follow-up).ResultsMean DHI scores improved significantly from 45.0 in the acute stage to 18.1 at follow-up (p < 0.001), and mean mRS improved from 2.1 to 1.1 (p < 0.001). Mean HRQoL (EQ-5D-5L index/EQ-VAS) changed from 0.69/58.8 to 0.83/65.2 (p = 0.01/p = 0.11). Multiple linear regression models identified higher scores of STAI-T and DHI at the time of acute vestibular stroke and larger stroke volume as significant predictors for higher DHI at follow-up assessment. The effect of STAI-T was additionally enhanced in women. There was a significant effect of patient age on EQ-VAS, but not DHI during follow-up.ConclusionThe average functional outcome of strokes with the chief complaint of vertigo and dizziness is favorable. The most relevant predictors for individual outcomes are the personal anxiety trait (especially in combination with the female sex), the initial symptom intensity, and lesion volume. These factors should be considered for therapeutic decisions both in the acute stage of stroke and during subsequent rehabilitation.

Resampling-based cost loss attention network for explainable imbalanced diabetic retinopathy grading

Diabetic retinopathy (DR) is currently considered to be one of the most common diseases that cause blindness. However, DR grading methods are still challenged by the presence of imbalanced class distributions, small lesions, low accuracy of small sample classes and poor explainability. To address these issues, a resampling-based cost loss attention network for explainable imbalanced diabetic retinopathy grading is proposed. First, the progressively-balanced resampling strategy is put forward to create a balanced training data by mixing the two sets of samples obtained from instance-based sampling and class-based sampling. Subsequently, a neuron and normalized channel-spatial attention module (Neu-NCSAM) is designed to learn the global features with 3-D weights and a weight sparsity penalty is applied to the attention module to suppress irrelevant channels or pixels, thereby capturing detailed small lesion information. Thereafter, a weighted loss function of the Cost-Sensitive (CS) regularization and Gaussian label smoothing loss, called cost loss, is proposed to intelligently penalize the incorrect predictions and thus to improve the grading accuracy of small sample classes. Finally, the Gradient-weighted Class Activation Mapping (Grad-CAM) is performed to acquire the localization map of the questionable lesions in order to visually interpret and understand the effect of our model. Comprehensive experiments are carried out on two public datasets, and the subjective and objective results demonstrate that the proposed network outperforms the state-of-the-art methods and achieves the best DR grading results with 83.46%, 60.44%, 65.18%, 63.69% and 92.26% for Kappa, BACC, MCC, F1 and mAUC, respectively.

Cervical cell lift: A novel triage method for the spatial mapping and grading of precancerous cervical lesions.

SummaryBackgroundPrimary HPV screening, due to its low specificity, requires an additional liquid-based cytology (LBC) triage test. However, even with LBC triage there has been a near doubling in the number of patients referred for colposcopy in recent years, the majority having low-grade disease.MethodsTo counter this, a triage test that generates a spatial map of the cervical surface at a molecular level has been developed which removes the subjectivity associated with LBC by facilitating identification of lesions in their entirety. 50 patients attending colposcopy were recruited to participate in a pilot study to evaluate the test. For each patient, cells were lifted from the cervix onto a membrane (cervical cell lift, CCL) and immunostained with a biomarker of precancerous cells, generating molecular maps of the cervical surface. These maps were analysed to detect high-grade lesions, and the results compared to the final histological diagnosis.FindingsWe demonstrated that spatial molecular mapping of the cervix has a sensitivity of 90% (95% CI 69-98) (positive predictive value 81% (95% CI 60-92)) for the detection of high-grade disease, and that AI-based analysis could aid disease detection through automated flagging of biomarker-positive cells.InterpretationSpatial molecular mapping of the CCL improved the rate of detection of high-grade disease in comparison to LBC, suggesting that this method has the potential to decisively identify patients with clinically relevant disease that requires excisional treatment.FundingCRUK Early Detection Project award, Jordan-Singer BSCCP award, Addenbrooke's Charitable Trust, UK-MRC, Janssen Pharmaceuticals/Advanced Sterilisation Products, and NWO.

Quantitative susceptibility mapping of both ring and non-ring white matter lesions in relapsing remitting multiple sclerosis

BackgroundRecent evidence suggests that the presence of magnetic susceptibility changes in MS lesions correlates with patients' expanded disability status scale (EDSS). PurposeThis study evaluated the presence of ring lesions (RLs) and non-RLs, as well as changes in lesion susceptibility and lesion volume over a two-year time period in relapsing-remitting multiple sclerosis (RRMS) patients and compared these measures to the EDSS. Study typeLongitudinal cohort. Materials and methodsA total of forty-three (43) patients with RRMS were recruited for this study. All subjects underwent 3 T MRI at baseline and forty-one (41) subjects had follow-up scans over a two-year period. The protocol included T2 fluid attenuated inversion recovery (FLAIR), pre- and post-contrast 2D T1-weighted gradient echo imaging and susceptibility weighted imaging (SWI) sequences. All data were acquired prior to gadolinium-based contrast agent injection except for SWI and post-contrast T1-weighted data. Mean and peak susceptibilities of lesions were measured using quantitative susceptibility mapping (QSM). For the RLs, inner−/outer-diameters from SWI data and absolute intensity from the FLAIR data were measured. The susceptibility and volumes of RLs and non-RLs were correlated with EDSS. ResultsThe number of RLs correlated positively with EDSS (p-value = 0.04), but the RL volumes did not show a correlation with EDSS. Measurements of the annular ring and regions with high susceptibility remained constant over time (p = 0.2). For non-ring QSM-positive (QSM+) lesions, the average susceptibility was significantly correlated to EDSS (p < 0.01.) This was also the case for lesion volume, as well as the product of volume and susceptibility when compared to EDSS (p < 0.01 for both). ConclusionsThe susceptibility distribution and lesion volumes for the RLs remained almost constant over time, suggesting that the changes in pathophysiology of the RLs is a gradual process. On the other hand, the presence of more than one RL along with both volume and susceptibility of non-RL QSM+ lesions were significantly associated with increased disability as measured by EDSS. These findings may strengthen the role of QSM in assessing MS patients radiologically.

Voxel-wise lesion mapping of restless legs syndrome in multiple sclerosis

ObjectiveRestless legs syndrome (RLS) is known to be associated with multiple sclerosis (MS) and may be caused by MS lesions in specific cerebral brain regions. Applying a voxel-wise lesion analysis, we tried to identify the contribution of cerebral MS lesions to RLS.MethodsIn this retrospective study, we established a cohort of people with MS with documented RLS and controls of people with MS without RLS matched disease severity. Diagnosis of MS and RLS was based on the current guidelines. The MS lesions were analyzed on T2-weighted magnetic resonance imaging scans (1.5 or 3 T). After manual delineation, lesion maps were converted into stereotaxic space. We generated a lesion overlap and performed a Liebermeister test with 4000 permutations to compare the absence or presence of RLS voxel-wise between patients with and without lesions in a given voxel.ResultsForty of the patients with RLS and MS fulfilled the inclusion criteria. The voxel-wise analysis yielded associations between RLS and MS in the subcortex of the left gyrus precentralis.ConclusionOur voxel-wise analysis shows associations in the subcortex of the left gyrus precentralis. Thus, our data suggests that a dysfunction of the efferent motor system due to cerebral lesions may contribute to the pathophysiology of RLS in MS.

Temporal Mapping of Trigeminal Neuralgia Lesions to Symptom Onset in Multiple Sclerosis: When Do the Lesions Occur and What Do They Tell Us? (P16-4.001)

Temporal Mapping of Trigeminal Neuralgia Lesions to Symptom Onset in Multiple Sclerosis: When Do the Lesions Occur and What Do They Tell Us? (P16-4.001)

Fluid and White Matter Suppression: New Sensitive 3 T Magnetic Resonance Imaging Contrasts for Cortical Lesion Detection in Multiple Sclerosis.

Cortical lesions are common in multiple sclerosis (MS), but their visualization is challenging on conventional magnetic resonance imaging. The uniform image derived from magnetization prepared 2 rapid acquisition gradient echoes (MP2RAGE uni ) detects cortical lesions with a similar rate as the criterion standard sequence, double inversion recovery. Fluid and white matter suppression (FLAWS) provides multiple reconstructed contrasts acquired during a single acquisition. These contrasts include FLAWS minimum image (FLAWS min ), which provides an exquisite sensitivity to the gray matter signal and therefore may facilitate cortical lesion identification, as well as high contrast FLAWS (FLAWS hco ), which gives a contrast that is similar to one of MP2RAGE uni . In this study, we compared the manual detection rate of cortical lesions on MP2RAGE uni , FLAWS min , and FLAWS hco in MS patients. Furthermore, we assessed whether the combined detection rate on FLAWS min and FLAWS hco was superior to MP2RAGE uni for cortical lesions identification. Last, we compared quantitative T1 maps (qT1) provided by both MP2RAGE and FLAWS in MS lesions. We included 30 relapsing-remitting MS patients who underwent MP2RAGE and FLAWS magnetic resonance imaging with isotropic spatial resolution of 1 mm at 3 T. Cortical lesions were manually segmented by consensus of 3 trained raters and classified as intracortical or leukocortical lesions on (1) MP2RAGE uniform/flat images, (2) FLAWS min , and (3) FLAWS hco . In addition, segmented lesions on FLAWS min and FLAWS hco were merged to produce a union lesion map (FLAWS min + hco ). Number and volume of all cortical, intracortical, and leukocortical lesions were compared among MP2RAGE uni , FLAWS min , and FLAWS hco using Friedman test and between MP2RAGE uni and FLAWS min + hco using Wilcoxon signed rank test. The FLAWS T1 maps were then compared with the reference MP2RAGE T1 maps using relative differences in percentage. In an exploratory analysis, individual cortical lesion counts of the 3 raters were compared, and interrater variability was quantified using Fleiss ϰ. In total, 633 segmentations were made on the 3 contrasts, corresponding to 355 cortical lesions. The median number and volume of single cortical, intracortical, and leukocortical lesions were comparable among MP2RAGE uni , FLAWS min , and FLAWS hco . In patients with cortical lesions (22/30), median cumulative lesion volume was larger on FLAWS min (587 μL; IQR, 1405 μL) than on MP2RAGE uni (490 μL; IQR, 990 μL; P = 0.04), whereas there was no difference between FLAWS min and FLAWS hco , or FLAWS hco and MP2RAGE uni . FLAWS min + hco showed significantly greater numbers of cortical (median, 4.5; IQR, 15) and leukocortical (median, 3.5; IQR, 12) lesions than MP2RAGE uni (median, 3; IQR, 10; median, 2.5; IQR, 7; both P < 0.001). Interrater agreement was moderate on MP2RAGE uni (ϰ = 0.582) and FLAWS hco (ϰ = 0.584), but substantial on FLAWS min (ϰ = 0.614). qT1 in lesions was similar between MP2RAGE and FLAWS. Cortical lesions identification in FLAWS min and FLAWS hco was comparable to MP2RAGE uni . The combination of FLAWS min and FLAWS hco allowed to identify a higher number of cortical lesions than MP2RAGE uni , whereas qT1 maps did not differ between the 2 acquisition schemes.

Post-stroke apathy: A case series investigation of neuropsychological and lesion characteristics

Apathy is a multi-dimensional syndrome associated with reduced initiation, executive function and emotion toward goal-directed behaviour. Affecting ∼30% of stroke patients, apathy can negatively impact rehabilitation outcomes and increase caregiver burden. However, relatively little is known about the multi-dimensional nature of post-stroke apathy and whether these dimensions map onto neuropsychological and neuroanatomical correlates. The present study aimed to address this question in a case series of stroke patients with apathy. 65 patients with acute stroke were assessed on a comprehensive battery of neuropsychological tasks and 12 patients were identified as having clinically significant apathy on one or more domains on the Dimensional Apathy Scale. Individual scores were compared to a group of healthy controls and normative data where available. Lesion mapping was completed from clinical CT and MRI scans to characterise the extent and locations of each patient's lesion. All participants performed significantly poorer than controls on one or more tasks. Difficulties with inhibition were observed across all dimensions. Prospective memory deficits were also common, while speed and social cognition were only reduced in initiation and emotional apathy, respectively. Verbal fluency was not impaired in any of the patients, despite previously established relationships with apathy. Lesions were predominantly located in right subcortical regions, with some additional frontal, temporal and cerebellar/brainstem involvement. There was substantial overlap in lesion locations within and between dimensions, such that similar apathy symptoms occurred in patients with very different lesion sites. Overall, our results suggest that neuropsychological and lesion profiles of apathy in stroke patients may be more complex and heterogenous than in neurodegenerative disease, possibly due to functional changes occurring beyond the lesion site.

Parathyroid Computed Tomography: Pearls, Pitfalls, and Our Approach.

Parathyroid imaging is predominantly used for preoperative localization of parathyroid lesions in patients with the biochemical diagnosis of primary hyperparathyroidism. Although imaging algorithms vary, in the era of minimally invasive parathyroidectomy for single parathyroid adenomas, multiphase parathyroid computed tomography (CT) (4-dimensional CT) has emerged as a favored modality for presurgical mapping of parathyroid lesions. Implementation and correct interpretation of these studies can be challenging, although confidence and accuracy improve with experience and volume. This article reviews our approach to parathyroid imaging, focusing on pearls and pitfalls in parathyroid CT with ultrasound as a supportive and complementary modality.

The influence of clinical characteristics on prism adaptation training in visuospatial neglect: A post-hoc analysis of a randomized controlled trial

Previous studies indicate that the effect of prism adaptation training (PAT) on unilateral neglect may depend on clinical characteristics. In this explorative work, we re-analyzed data from a previously conducted randomized controlled trial (N = 23) to investigate whether age, etiology, severity of motor impairments, and visual field deficits affect the efficacy of PAT. Additionally, we reviewed PAT studies that reported lesion maps and distinguished responders from non-responders. We transferred these maps into a common standard brain and added data from 12 patients from our study. We found patients suffering from subarachnoid bleeding appeared to show stronger functional recovery than those with intracranial hemorrhage or cortical infarction. Furthermore, patients with visual field deficits and those with more severe contralateral motor impairments had larger after-effect sizes but did not differ in treatment effects. In addition, patients with parietal lesions showed reduced recovery, whereas patients with lesions in the basal ganglia recovered better. We conclude that PAT (in its current form) is effective when fronto-subcortical areas are involved but it may not be the best choice when parietal regions are affected. Overall, the present work adds to the understanding on the effects of clinical characteristics on PAT.

Evidence of the role of the cerebellum in cognitive theory of mind using voxel-based lesion mapping

Theory of Mind (ToM) is a social-cognitive skill that allows the understanding of the intentions, beliefs, and desires of others. There is a distinction between affective and cognitive ToM, with evidence showing that these processes rely on partially distinct neural networks. The role of the cerebellum in social cognition has only been rarely explored. In this study, we tested whether the cerebellum is necessary for cognitive and affective ToM performance. We investigated adults with traumatic brain injury (n = 193) and healthy controls (n = 52) using voxel-based lesion-symptom mapping (VLSM) and by measuring the impact on functional connectivity. First, we observed that damage to the cerebellum affected pure Cognitive ToM processing. Further, we found a lateralization effect for the role of the cerebellum in cognitive ToM with participants with left cerebellar injury performing worse than those with right cerebellar injury. Both VLSM and standard statistical analysis provided evidence that left cerebellar Crus I and lobule VI contributed to ToM processing. Lastly, we found that disconnection of the left thalamic projection and the left fronto-striatal fasciculus was associated with poor cognitive ToM performance. Our study is the first to reveal direct causal neuropsychological evidence for a role of the cerebellum in some but not all types of ToM, processing. It reinforces the idea that social cognition relies on a complex network functionally connected through white matter pathways that include the cerebellum. It supports evidence that the neural networks underpinning the different types of ToM can be differentiated.