Publications by authors named "Noriko Salamon"

175 Publications

Relationship Between Superior Semicircular Canal Dehiscence Volume with Clinical Symptoms: Case Series.

World Neurosurg 2021 Sep 23. Epub 2021 Sep 23.

Department of Neurosurgery, Ronald Reagan UCLA Medical Center, University of California Los Angeles, Los Angeles, California, USA; Department of Head and Neck Surgery, Ronald Reagan UCLA Medical Center, University of California Los Angeles, Los Angeles, California, USA; Department of Radiation Oncology, Ronald Reagan UCLA Medical Center, University of California Los Angeles, Los Angeles, California, USA; David Geffen School of Medicine, Ronald Reagan UCLA Medical Center, University of California Los Angeles, Los Angeles, California, USA; Jonsson Comprehensive Cancer Center, Ronald Reagan UCLA Medical Center, University of California Los Angeles, Los Angeles, California, USA; Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, University of California Los Angeles, Los Angeles, California, USA. Electronic address:

Background: Superior semicircular canal dehiscence (SSCD) is an osseous defect of the arcuate eminence of the petrosal temporal bone. Patients typically present with auditory and vestibular symptoms, such as hearing loss and disequilibrium. Using advanced imaging segmentation techniques, we evaluated whether the volume of SSCD correlated with preoperative symptoms and postoperative outcomes.

Methods: Our laboratory previously described a novel method of quantifying the size of an SSCD via manual segmentation. High-resolution computed tomography images of the temporal bones were imported into a specialized segmentation software. The volume of the dehiscence was outlined on consecutive slices of the coronal and axial planes via a single-pixel-thick paintbrush tool and was then calculated according to the number of nonzero image voxels.

Results: This study included 111 patients (70 women and 41 men; mean age, 55.1 years; age range, 24-87 years) with a total of 164 SSCDs. Mean postoperative follow-up time was 5.2 months (range, 0.03-59.5 months). The most common preoperative and postoperative symptoms were tinnitus (n = 85) and dizziness (n = 45), respectively. Surgery resulted in improvement of symptoms in most patients. The average volume of 164 SSCDs was 1.3 mm. SSCD volume was not significantly associated with either preoperative symptoms or postoperative outcomes.

Conclusions: Advances in imaging techniques have allowed increased visualization of SSCD. Further research will be necessary to evaluate the potential correlation of volume of the dehiscence with clinical variables.
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http://dx.doi.org/10.1016/j.wneu.2021.09.070DOI Listing
September 2021

Sex-Dependent Cortical Volume Changes in Patients with Degenerative Cervical Myelopathy.

J Clin Med 2021 Sep 1;10(17). Epub 2021 Sep 1.

UCLA Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90024, USA.

Degenerative cervical myelopathy (DCM) is a progressive condition characterized by degeneration of osseocartilaginous structures within the cervical spine resulting in compression of the spinal cord and presentation of clinical symptoms. Compared to healthy controls (HCs), studies have shown DCM patients experience structural and functional reorganization in the brain; however, sex-dependent cortical differences in DCM patients remains largely unexplored. In the present study, we investigate the role of sex differences on the structure of the cerebral cortex in DCM and determine how structural differences may relate to clinical measures of neurological function. T1-weighted structural MRI scans were acquired in 85 symptomatic and asymptomatic patients with DCM and 90 age-matched HCs. Modified Japanese Orthopedic Association (mJOA) scores were obtained for patients. A general linear model was used to determine vertex-level significant differences in gray matter volume (GMV) between the following groups (1) male HCs and female HCs, (2) male patients and female patients, (3) male patients and male HCs, and (4) female patients and female HCs. Within patients, males exhibited larger GMV in motor, language, and vision related brain regions compared to female DCM patients. Males demonstrated a significant positive correlation between GMV and mJOA score, in which patients with worsening neurological symptoms exhibited decreasing GMV primarily across somatosensory and motor related cortical regions. Females exhibited a similar association, albeit across a broader range of cortical areas including those involved in pain processing. In sensorimotor regions, female patients consistently showed smaller GMV compared with male patients, independent of mJOA score. Results from the current study suggest strong sex-related differences in cortical volume in patients with DCM, which may reflect hormonal influence or differing compensation mechanisms.
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http://dx.doi.org/10.3390/jcm10173965DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8432178PMC
September 2021

Characterization of cognitive function in survivors of diffuse gliomas using resting-state functional MRI (rs-fMRI).

Brain Imaging Behav 2021 Aug 5. Epub 2021 Aug 5.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, 924 Westwood Blvd., Suite 615, Los Angeles, CA, 90024, USA.

As treatments for diffuse gliomas have advanced, survival for patients with gliomas has also increased. However, there remains limited knowledge on the relationships between brain connectivity and the lasting changes to cognitive function that glioma survivors often experience long after completing treatment. This resting-state functional magnetic resonance imaging (rs-fMRI) study explored functional connectivity (FC) alterations associated with cognitive function in survivors of gliomas. In this pilot study, 22 patients (mean age 43.8 ± 11.9) with diffuse gliomas who completed treatment within the past 10 years were evaluated using rs-fMRI and neuropsychological measures. Novel rs-fMRI analysis methods were used to account for missing brain in the resection cavity. FC relationships were assessed between cognitively impaired and non-impaired glioma patients, along with self-reported cognitive impairment, non-work daily functioning, and time with surgery. In the cognitively non-impaired patients, FC was stronger in the medial prefrontal cortex, rostral prefrontal cortex, and intraparietal sulcus compared to the impaired survivors. When examining non-work daily functioning, a positive correlation with FC was observed between the accumbens and the intracalcarine cortices, while a negative correlation with FC was observed between the parietal operculum cortex and the cerebellum. Additionally, worse self-reported cognitive impairment and worse non-work daily functioning were associated with increased FC between regions involved in cognition and sensorimotor processing. These preliminary findings suggest that neural correlates for cognitive and daily functioning in glioma patients can be revealed using rs-fMRI. Resting-state network alterations may serve as a biomarker for patients' cognition and functioning.
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http://dx.doi.org/10.1007/s11682-021-00497-6DOI Listing
August 2021

A minority of patients with functional seizures have abnormalities on neuroimaging.

J Neurol Sci 2021 Aug 18;427:117548. Epub 2021 Jun 18.

Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.

Objective: Functional seizures often are managed incorrectly as a diagnosis of exclusion. However, a significant minority of patients with functional seizures may have abnormalities on neuroimaging that typically are associated with epilepsy, leading to diagnostic confusion. We evaluated the rate of epilepsy-associated findings on MRI, FDG-PET, and CT in patients with functional seizures.

Methods: We studied radiologists' reports from neuroimages at our comprehensive epilepsy center from a consecutive series of patients diagnosed with functional seizures without comorbid epilepsy from 2006 to 2019. We summarized the MRI, FDG-PET, and CT results as follows: within normal limits, incidental findings, unrelated findings, non-specific abnormalities, post-operative study, epilepsy risk factors (ERF), borderline epilepsy-associated findings (EAF), and definitive EAF.

Results: Of the 256 MRIs, 23% demonstrated ERF (5%), borderline EAF (8%), or definitive EAF (10%). The most common EAF was hippocampal sclerosis, with the majority of borderline EAF comprising hippocampal atrophy without T2 hyperintensity or vice versa. Of the 87 FDG-PETs, 26% demonstrated borderline EAF (17%) or definitive EAF (8%). Epilepsy-associated findings primarily included focal hypometabolism, especially of the temporal lobes, with borderline findings including subtle or questionable hypometabolism. Of the 51 CTs, only 2% had definitive EAF.

Significance: This large case series provides further evidence that, while uncommon, EAF are seen in patients with functional seizures. A significant portion of these abnormal findings are borderline. The moderately high rate of these abnormalities may represent framing bias from the indication of the study being "seizures," the relative subtlety of EAF, or effects of antiseizure medications.
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http://dx.doi.org/10.1016/j.jns.2021.117548DOI Listing
August 2021

Epilepsy in Sero-Positive Patients From Northern Uganda-Clinical, EEG and Brain Imaging Features.

Front Neurol 2021 3;12:687281. Epub 2021 Jun 3.

College of Health Sciences, Makerere University, Kampala, Uganda.

Globally, epilepsy is the most common chronic neurological disorder. The incidence in sub-Saharan Africa is 2-3 times higher than that in high income countries. Infection by may be an underlying risk factor for the high burden and based upon epidemiological associations, has been proposed to cause a group of disorders- associated epilepsies (OAE) like nodding syndrome (NS). To improve our understanding of the disease spectrum, we described the clinical, electroencephalographic (EEG) and magnetic resonance imaging (MRI) features of children with epilepsy and sero-positive for (possible OAEs other than nodding syndrome). Twenty-nine children and adolescents with non-nodding syndrome OAE in northern Uganda were enrolled. A diagnosis of OAE was made in patients with epilepsy and seizure onset after age 3 years, no reported exposure to perinatal severe febrile illness or traumatic brain injury, no syndromic epilepsy diagnosis and a positive Ov-16 ELISA test. Detailed clinical evaluation including psychiatric, diagnostic EEG, a diagnostic brain MRI (in 10 patients) and laboratory testing were performed. Twenty participants (69%) were male. The mean age was 15.9 (standard deviation [SD] 1.9) years while the mean age at seizure onset was 9.8 (SD 2.9) years. All reported normal early childhood development. The most common clinical presentation was a tonic-clonic seizure. The median number of seizures was 2 (IQR 1-4) in the previous month. No specific musculoskeletal changes, or cranial nerve palsies were reported, neither were any vision, hearing and speech difficulties observed. The interictal EEG was abnormal in the majority with slow wave background activity in 52% (15/29) while 41% (12/29) had focal epileptiform activity. The brain MRI showed mild to moderate cerebellar atrophy and varying degrees of atrophy of the frontal, parietal and occipital lobes. The clinical spectrum of epilepsies associated with Onchocerca may be broader than previously described. In addition, focal onset tonic-clonic seizures, cortical and cerebellar atrophy may be important brain imaging and clinical features.
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http://dx.doi.org/10.3389/fneur.2021.687281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8209377PMC
June 2021

Worse prognosis for IDH wild-type diffuse gliomas with larger residual biological tumor burden.

Ann Nucl Med 2021 Sep 14;35(9):1022-1029. Epub 2021 Jun 14.

UCLA Brain Tumor Imaging Laboratory (BTIL), David Geffen School of Medicine, University of California Los Angeles, Los Angeles, USA.

Objective: The association of overall survival (OS) with tumor burden, including contrast enhanced (CE) volume on CE T1-weighted images, fluid-attenuated inversion recovery (FLAIR) hyperintense volume, and 3, 4-dihydroxy-6-[F]-fluoro-L-phenylalanine (FDOPA) hypermetabolic volume, in isocitrate dehydrogenase (IDH) wild-type gliomas remains unclear. This study aimed to assess the association between biological tumor burden in pre- and post-operative status and OS in IDH wild-type gliomas, and evaluated which volume was the best predictor of OS.

Methods: Thirty-four patients with treatment-naïve IDH wild-type gliomas (WHO grade II 6, III 15, IV 13) were retrospectively included. Three pre-operative tumor regions of interest (ROIs) were segmented based on the CE, FLAIR hyperintense, and FDOPA hypermetabolic regions. Resected ROIs were segmented from the post-operative images. Residual CE, FLAIR hyperintense, and FDOPA hypermetabolic ROIs were created by subtracting resected ROIs from pre-operative ROIs. Cox regression analysis was conducted to investigate the association of OS with the volume of each ROI, and Akaike information criterion was used to assess the fitness.

Results: Residual CE volume had a significant association with OS [hazard ratio (HR) = 1.26, p = 0.039], but this effect disappeared when controlling for tumor grade. Residual FDOPA hypermetabolic volume best fit the regression model and was significantly associated with OS (HR = 1.18, p = 0.008), even when controlling for tumor grade. FLAIR hyperintense volume showed no significant association with OS.

Conclusion: Residual FDOPA hypermetabolic burden predicted OS for IDH wild-type gliomas, regardless of the tumor grade. Furthermore, removing hypermetabolic and CE regions may improve the prognosis.
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http://dx.doi.org/10.1007/s12149-021-01637-0DOI Listing
September 2021

Supraspinal functional and structural plasticity in patients undergoing surgery for degenerative cervical myelopathy.

J Neurosurg Spine 2021 Jun 11:1-9. Epub 2021 Jun 11.

2Neurosurgery, and.

Objective: The aim of this study was to investigate cerebral reorganization, both structurally and functionally, occurring in patients with degenerative cervical myelopathy (DCM) after surgical decompression.

Methods: In the current observational study of 19 patients, high-resolution T1-weighted structural MRI and resting-state functional MRI scans were obtained pre- and postoperatively in patients with DCM and healthy controls (HCs). The resting-state functional MRI data were utilized to perform region-of-interest (ROI)-to-ROI and ROI-to-voxel functional connectivity (FC) analysis and were similarly compared between and within cohorts. Macroscopic structural plasticity was evaluated by assessing for changes in cortical thickness within the DCM cohort after decompression surgery.

Results: Prior to surgery, FC patterns were significantly different between DCM patients and HCs in cerebral areas responsible for postural control, motor regulation, and perception and integration of sensory information. Significantly stronger FC between the cerebellum and frontal lobes was identified in DCM patients postoperatively compared with DCM patients preoperatively. Additionally, increased FC between the cerebellum and primary sensorimotor areas was found to be positively associated with neurological improvement in patients with DCM. No macroscopic structural changes were observed in the DCM patients after surgery.

Conclusions: These results support the authors' hypothesis that functional changes within the brain are associated with effective postoperative recovery, particularly in regions associated with motor regulation and with perception and integration of sensory information. In particular, increased FC between the cerebellum and the primary sensorimotor after surgery appears to be associated with neurological improvement. Macroscopic morphological changes may be too subtle to be detected within 3 months after surgery.
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http://dx.doi.org/10.3171/2020.11.SPINE201688DOI Listing
June 2021

Multiparametric MRI texture analysis in prediction of glioma biomarker status: added value of MR diffusion.

Neurooncol Adv 2021 Jan-Dec;3(1):vdab051. Epub 2021 Apr 8.

Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

Background: Early identification of glioma molecular phenotypes can lead to understanding of patient prognosis and treatment guidance. We aimed to develop a multiparametric MRI texture analysis model using a combination of conventional and diffusion MRI to predict a wide range of biomarkers in patients with glioma.

Methods: In this retrospective study, patients were included if they (1) had diagnosis of gliomas with known , , , , , and status from surgical pathology and (2) had preoperative MRI including FLAIR, T1c+ and diffusion for radiomic texture analysis. Statistical analysis included logistic regression and receiver-operating characteristic (ROC) curve analysis to determine the optimal model for predicting glioma biomarkers. A comparative analysis between ROCs (conventional only vs conventional + diffusion) was performed.

Results: From a total of 111 patients included, 91 (82%) were categorized to training and 20 (18%) to test datasets. Constructed cross-validated model using a combination of texture features from conventional and diffusion MRI resulted in overall AUC/accuracy of 1/79% for , 0.99/80% for , 0.79/67% for , and 0.77/66% for . The addition of diffusion data to conventional MRI features significantly ( < .05) increased predictive performance for , , and . The overall accuracy of the final model in predicting biomarkers in the test group was 80% (), 70% (), 70% (), and 75% ().

Conclusion: Addition of MR diffusion to conventional MRI features provides added diagnostic value in preoperative determination of IDH1, MGMT, and ATRX in patients with glioma.
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http://dx.doi.org/10.1093/noajnl/vdab051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8156980PMC
April 2021

Intra-domain task-adaptive transfer learning to determine acute ischemic stroke onset time.

Comput Med Imaging Graph 2021 06 24;90:101926. Epub 2021 Apr 24.

Computational Diagnostics Lab, University of California, Los Angeles, CA 90024, USA; Department of Bioengineering, University of California, Los Angeles, CA 90024, USA; Department of Radiology, University of California, Los Angeles, CA 90024, USA; Department of Pathology, University of California, Los Angeles, CA 90024, USA.

Treatment of acute ischemic strokes (AIS) is largely contingent upon the time since stroke onset (TSS). However, TSS may not be readily available in up to 25% of patients with unwitnessed AIS. Current clinical guidelines for patients with unknown TSS recommend the use of MRI to determine eligibility for thrombolysis, but radiology assessments have high inter-reader variability. In this work, we present deep learning models that leverage MRI diffusion series to classify TSS based on clinically validated thresholds. We propose an intra-domain task-adaptive transfer learning method, which involves training a model on an easier clinical task (stroke detection) and then refining the model with different binary thresholds of TSS. We apply this approach to both 2D and 3D CNN architectures with our top model achieving an ROC-AUC value of 0.74, with a sensitivity of 0.70 and a specificity of 0.81 for classifying TSS < 4.5 h. Our pretrained models achieve better classification metrics than the models trained from scratch, and these metrics exceed those of previously published models applied to our dataset. Furthermore, our pipeline accommodates a more inclusive patient cohort than previous work, as we did not exclude imaging studies based on clinical, demographic, or image processing criteria. When applied to this broad spectrum of patients, our deep learning model achieves an overall accuracy of 75.78% when classifying TSS < 4.5 h, carrying potential therapeutic implications for patients with unknown TSS.
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http://dx.doi.org/10.1016/j.compmedimag.2021.101926DOI Listing
June 2021

Understanding the sodium cation conductivity of human epileptic brain tissue.

AIP Adv 2021 Apr 16;11(4):045118. Epub 2021 Apr 16.

Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, USA.

Transient and frequency-dependent conductivity measurements on excised brain-tissue lesions from epilepsy patients indicate that sodium cations are the predominant charge carriers. The transient conductivity ultimately vanishes as ions encounter blockages. The initial and final values of the transient conductivity correspond to the high-frequency and low-frequency limits of the frequency-dependent conductivity, respectively. Carrier dynamics determines the conductivity between these limits. Typically, the conductivity rises monotonically with increasing frequency. By contrast, when pathology examinations found exceptionally disorganized excised tissue, the conductivity falls with increasing frequency as it approaches its high-frequency limit. To analyze these measurements, excised tissues are modeled as mixtures of "normal" tissue within which sodium cations can diffuse and "abnormal" tissue within which sodium cations are trapped. The decrease in the conductivity with increasing frequency indicates the predominance of trapping. The high-frequency conductivity decreases as the rate with which carriers are liberated from traps decreases. A relatively low conductivity results when most sodium cations remain trapped in "abnormal" brain tissue, while few move within "normal" brain tissue. Thus, the high densities of sodium nuclei observed by Na-MRI in epilepsy patients' lesions are consistent with the low densities of diffusing sodium cations inferred from conductivity measurements of excised lesions.
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http://dx.doi.org/10.1063/5.0041906DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8053039PMC
April 2021

Acute Ischemic Stroke: MR Imaging-Based Paradigms.

Neuroimaging Clin N Am 2021 May;31(2):177-192

Department of Neurology, David Geffen School of Medicine at University of California Los Angeles, Neuroscience Research Building, 635 Charles E Young Drive South, Suite 225, Los Angeles, CA 90095-7334, USA.

Multimodal MR imaging provides valuable information in the management of patients with acute ischemic stroke (AIS), with diagnostic, therapeutic, and prognostic implications. MR imaging plays a critical role in treatment decision making for (1) thrombolytic treatment of AIS patients with unknown symptom-onset and (2) endovascular treatment of patients with large vessel occlusion presenting beyond 6 hours from the symptom onset. MR imaging provides the most accurate information for detection of ischemic brain and is invaluable for differentiating AIS from stroke mimics.
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http://dx.doi.org/10.1016/j.nic.2021.01.002DOI Listing
May 2021

Clonally Focused Public and Private T Cells in Resected Brain Tissue From Surgeries to Treat Children With Intractable Seizures.

Front Immunol 2021 6;12:664344. Epub 2021 Apr 6.

Department of Neurosurgery, David Geffen School of Medicine at the University of California, Los Angeles, CA, United States.

Using a targeted transcriptomics approach, we have analyzed resected brain tissue from a cohort of 53 pediatric epilepsy surgery cases, and have found that there is a spectrum of involvement of both the innate and adaptive immune systems as evidenced by the differential expression of immune-specific genes in the affected brain tissue. The specimens with the highest expression of immune-specific genes were from two Rasmussen encephalitis cases, which is known to be a neuro-immunological disease, but also from tuberous sclerosis complex (TSC), focal cortical dysplasia, and hemimegalencephaly surgery cases. We obtained T cell receptor (TCR) Vβ chain sequence data from brain tissue and blood from patients with the highest levels of T cell transcripts. The clonality indices and the frequency of the top 50 Vβ clonotypes indicated that T cells in the brain were clonally restricted. The top 50 Vβ clonotypes comprised both public and private (patient specific) clonotypes, and the TCR Vβ chain third complementarity region (CDR3) of the most abundant public Vβ clonotype in each brain sample was strikingly similar to a CDR3 that recognizes an immunodominant epitope in either human cytomegalovirus or Epstein Barr virus, or influenza virus A. We found that the frequency of 14 of the top 50 brain Vβ clonotypes from a TSC surgery case had significantly increased in brain tissue removed to control recurrent seizures 11 months after the first surgery. Conversely, we found that the frequency in the blood of 18 of the top 50 brain clonotypes from a second TSC patient, who was seizure free, had significantly decreased 5 months after surgery indicating that T cell clones found in the brain had contracted in the periphery after removal of the brain area associated with seizure activity and inflammation. However, the frequency of a public and a private clonotype significantly increased in the brain after seizures recurred and the patient underwent a second surgery. Combined single cell gene expression and TCR sequencing of brain-infiltrating leukocytes from the second surgery showed that the two clones were CD8 effector T cells, indicating that they are likely to be pathologically relevant.
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http://dx.doi.org/10.3389/fimmu.2021.664344DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8056262PMC
October 2021

Association of hypometabolic extension of F-FDG PET with diffusion tensor imaging indices in mesial temporal lobe epilepsy with hippocampal sclerosis.

Seizure 2021 May 18;88:130-137. Epub 2021 Apr 18.

Department of Radiological Science, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave, Los Angeles, CA 90095, USA.

Purpose: To assess the association between hypometabolic extension of F-fluorodeoxyglucose positron emission tomography and diffusion tensor imaging indices, including mean diffusivity (MD) and fractional anisotropy (FA), in hippocampal sclerosis (HS).

Methods: Thirty-six unilateral HS were retrospectively selected and stratified into two groups: broad and localized hypometabolic groups (hypometabolism beyond [n = 26] and within the temporal lobe [n = 10]). Forty-one pairs of gray matter (GM) regions of interest (ROIs) were segmented using FreeSurfer software. The GM ROIs were applied to MD maps, and median MD values within each ROI were compared between hemispheres ipsilateral and contralateral to HS using a mixed effect model. Tract-Based Spatial Statistics (TBSS) was used to evaluate FA of white matter (WM) tracts between hemispheres ipsilateral and contralateral to HS. Disease laterality was controlled for.

Results: The MD values in the thalamus, caudate, hippocampus, amygdala, superior frontal gyrus, middle and inferior temporal gyrus, temporal pole, and isthmus cingulate gyrus were significantly higher in the HS side than the contralateral side for the broad hypometabolic group. Those in the amygdala and superior temporal sulcus were significantly higher in the HS side than the contralateral side for the localized group. The TBSS analyses showed significantly decreased FA in the WM tracts of the temporal and frontal lobes for the broad hypometabolic group, while no tracts showed significant differences for the localized group.

Conclusion: The hypometabolic extension for HS was associated with the abnormalities of MD and FA in GM and WM, respectively, with more widespread microstructural alterations for broad hypometabolic HS.
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http://dx.doi.org/10.1016/j.seizure.2021.04.007DOI Listing
May 2021

A Framework for Sharing Radiation Dose Distribution Maps in the Electronic Medical Record for Improving Multidisciplinary Patient Management.

Radiol Imaging Cancer 2021 03 12;3(2):e200075. Epub 2021 Mar 12.

Departments of Radiation Oncology (R.R.S., J.D., M.M., S.T., N.A., J.H., T.K.) and Radiology (N.S.), UCLA David Geffen School of Medicine, 200 UCLA Medical Plaza, Suite B265, Los Angeles, CA 90095.

Radiation oncology practices use a suite of dedicated software and hardware that are not common to other medical subspecialties, making radiation treatment history inaccessible to colleagues. A radiation dose distribution map is generated for each patient internally that allows for visualization of the dose given to each anatomic structure volumetrically; however, this crucial information is not shared systematically to multidisciplinary medical, surgery, and radiology colleagues. A framework was developed in which dose distribution volumes are uploaded onto the medical center's picture archiving and communication system (PACS) to rapidly retrieve and review exactly where, when, and to what dose a lesion or structure was treated. The ability to easily visualize radiation therapy information allows radiology clinics to incorporate radiation dose into image interpretation without direct access to radiation oncology planning software and data. Tumor board discussions are simplified by incorporating radiation therapy information collectively in real time, and daily onboard imaging can also be uploaded while a patient is still undergoing radiation therapy. Placing dose distribution information into PACS facilitates central access into the electronic medical record and provides a succinct visual summary of a patient's radiation history for all medical providers. More broadly, the radiation dose map provides greater visibility and facilitates incorporation of a patient's radiation history to improve oncologic decision making and patient outcomes. Brain/Brain Stem, CNS, MRI, Neuro-Oncology, Radiation Effects, Radiation Therapy, Radiation Therapy/Oncology, Radiosurgery, Skull Base, Spine, Technology Assessment © RSNA, 2021 See also commentary by Khandelwal and Scarboro in this issue.
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http://dx.doi.org/10.1148/rycan.2021200075DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8011443PMC
March 2021

Detection of cerebral reorganization associated with degenerative cervical myelopathy using diffusion spectral imaging (DSI).

J Clin Neurosci 2021 Apr 5;86:164-173. Epub 2021 Feb 5.

Dept. of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA; Neuroscience Interdisciplinary Graduate Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA; Dept. of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.

Degenerative Cervical Myelopathy (DCM) is a spinal cord disorder that causes significant physical disabilities in older patients. While most DCM research focuses on the spinal cord, widespread reorganization of the brain may occur to compensate for functional impairment. This observational study used diffusion spectrum imaging (DSI) to examine reorganization of cerebral white matter associated with neurological impairment as measured by the modified Japanese Orthopedic Association (mJOA), and severity of neck disability as measured by the Neck Disability Index (NDI) score. A total of 47 patients were included in the cervical spondylosis (CS) cohort: 38 patients with DCM (mean mJOA = 14.6, and mean NDI = 12.0), and 9 neurologically asymptomatic patients with spinal cord compression (mJOA = 18, and mean NDI = 7.0). 28 healthy volunteers (HCs) served as the control group. Lower generalized fractional anisotropy (GFA) was observed throughout much of the brain in patients compared to HCs (p < 0.05). Fiber pathways associated with somatosensory functions, such as the corpus callosum and corona radiata, showed increased quantitative anisotropy (QA) in patients compared to HCs. Correlation analyses further suggested that structural connectivity was enhanced to compensate for neurological dysfunction within sensorimotor regions, where fibers such as the posterior corona radiata had NQA values that were negatively associated with mJOA (p = 0.0020, R = 0.2935) and positively associated with NDI score (p = 0.0164, R = 0.1889). Altogether, these results suggest that DCM and neurologically asymptomatic spinal cord compression patients tend to have long-term reorganization within the brain, particularly in those regions responsible for the perception and integration of sensory information, motor regulation, and pain modulation.
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http://dx.doi.org/10.1016/j.jocn.2021.01.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8007933PMC
April 2021

Preferential tumor localization in relation to F-FDOPA uptake for lower-grade gliomas.

J Neurooncol 2021 May 11;152(3):573-582. Epub 2021 Mar 11.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, 924 Westwood Blvd., Suite 615, Los Angeles, CA, 90024, USA.

Purpose: Although tumor localization and 3,4-dihydroxy-6-F-fluoro-L-phenylalanine (FDOPA) uptake may have an association, preferential tumor localization in relation to FDOPA uptake is yet to be investigated in lower-grade gliomas (LGGs). This study aimed to identify differences in the frequency of tumor localization between FDOPA hypometabolic and hypermetabolic LGGs using a probabilistic radiographic atlas.

Methods: Fifty-one patients with newly diagnosed LGG (WHO grade II, 29; III, 22; isocitrate dehydrogenase wild-type, 21; mutant 1p19q non-codeleted,16; mutant codeleted, 14) who underwent FDOPA positron emission tomography (PET) were retrospectively selected. Semiautomated tumor segmentation on FLAIR was performed. Patients with LGGs were separated into two groups (FDOPA hypometabolic and hypermetabolic LGGs) according to the normalized maximum standardized uptake value of FDOPA PET (a threshold of the uptake in the striatum) within the segmented regions. Spatial normalization procedures to build a 3D MRI-based atlas using each segmented region were validated by an analysis of differential involvement statistical mapping.

Results: Superimposition of regions of interest showed a high number of hypometabolic LGGs localized in the frontal lobe, while a high number of hypermetabolic LGGs was localized in the insula, putamen, and temporal lobe. The statistical mapping revealed that hypometabolic LGGs occurred more frequently in the superior frontal gyrus (close to the supplementary motor area), while hypermetabolic LGGs occurred more frequently in the insula.

Conclusion: Radiographic atlases revealed preferential frontal lobe localization for FDOPA hypometabolic LGGs, which may be associated with relatively early detection.
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http://dx.doi.org/10.1007/s11060-021-03730-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8221401PMC
May 2021

Differentiating IDH status in human gliomas using machine learning and multiparametric MR/PET.

Cancer Imaging 2021 Mar 10;21(1):27. Epub 2021 Mar 10.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, USA.

Background: The purpose of this study was to develop a voxel-wise clustering method of multiparametric magnetic resonance imaging (MRI) and 3,4-dihydroxy-6-[F]-fluoro-L-phenylalanine (FDOPA) positron emission tomography (PET) images using an unsupervised, two-level clustering approach followed by support vector machine in order to classify the isocitrate dehydrogenase (IDH) status of gliomas.

Methods: Sixty-two treatment-naïve glioma patients who underwent FDOPA PET and MRI were retrospectively included. Contrast enhanced T1-weighted images, T2-weighted images, fluid-attenuated inversion recovery images, apparent diffusion coefficient maps, and relative cerebral blood volume maps, and FDOPA PET images were used for voxel-wise feature extraction. An unsupervised two-level clustering approach, including a self-organizing map followed by the K-means algorithm was used, and each class label was applied to the original images. The logarithmic ratio of labels in each class within tumor regions was applied to a support vector machine to differentiate IDH mutation status. The area under the curve (AUC) of receiver operating characteristic curves, accuracy, and F1-socore were calculated and used as metrics for performance.

Results: The associations of multiparametric imaging values in each cluster were successfully visualized. Multiparametric images with 16-class clustering revealed the highest classification performance to differentiate IDH status with the AUC, accuracy, and F1-score of 0.81, 0.76, and 0.76, respectively.

Conclusions: Machine learning using an unsupervised two-level clustering approach followed by a support vector machine classified the IDH mutation status of gliomas, and visualized voxel-wise features from multiparametric MRI and FDOPA PET images. Unsupervised clustered features may improve the understanding of prioritizing multiparametric imaging for classifying IDH status.
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http://dx.doi.org/10.1186/s40644-021-00396-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7944911PMC
March 2021

Novel tonometer device distinguishes brain stiffness in epilepsy surgery.

Sci Rep 2020 12 1;10(1):20978. Epub 2020 Dec 1.

Department of Neurosurgery, David Geffen School of Medicine at UCLA, 300 Stein Plaza, Suite 525, Los Angeles, CA, 90095-6901, USA.

Complete surgical resection of abnormal brain tissue is the most important predictor of seizure freedom following surgery for cortical dysplasia. While lesional tissue is often visually indiscernible from normal brain, anecdotally, it is subjectively stiffer. We report the first experience of the use of a digital tonometer to understand the biomechanical properties of epilepsy tissue and to guide the conduct of epilepsy surgery. Consecutive epilepsy surgery patients (n = 24) from UCLA Mattel Children's Hospital were recruited to undergo intraoperative brain tonometry at the time of open craniotomy for epilepsy surgery. Brain stiffness measurements were corrected with abnormalities on neuroimaging and histopathology using mixed-effects multivariable linear regression. We collected 249 measurements across 30 operations involving 24 patients through the pediatric epilepsy surgery program at UCLA Mattel Children's Hospital. On multivariable mixed-effects regression, brain stiffness was significantly associated with the presence of MRI lesion (β = 32.3, 95%CI 16.3-48.2; p < 0.001), severity of cortical disorganization (β = 19.8, 95%CI 9.4-30.2; p = 0.001), and recent subdural grid implantation (β = 42.8, 95%CI 11.8-73.8; p = 0.009). Brain tonometry offers the potential of real-time intraoperative feedback to identify abnormal brain tissue with millimeter spatial resolution. We present the first experience with this novel intraoperative tool for the conduct of epilepsy surgery. A carefully designed prospective study is required to elucidate whether the clinical application of brain tonometry during resective procedures could guide the area of resection and improve seizure outcomes.
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http://dx.doi.org/10.1038/s41598-020-77888-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7708453PMC
December 2020

Relative oxygen extraction fraction (rOEF) MR imaging reveals higher hypoxia in human epidermal growth factor receptor (EGFR) amplified compared with non-amplified gliomas.

Neuroradiology 2021 Jun 26;63(6):857-868. Epub 2020 Oct 26.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.

Purpose: Epidermal growth factor receptor (EGFR) amplification promotes gliomagenesis and is linked to lack of oxygen within the tumor microenvironment. Using hypoxia-sensitive spin-and-gradient echo echo-planar imaging and perfusion MRI, we investigated the influence of EGFR amplification on tissue oxygen availability and utilization in human gliomas.

Methods: This study included 72 histologically confirmed EGFR-amplified and non-amplified glioma patients. Reversible transverse relaxation rate (R'), relative cerebral blood volume (rCBV), and relative oxygen extraction fraction (rOEF) were calculated for the contrast-enhancing and non-enhancing tumor regions. Using Student t test or Wilcoxon rank-sum test, median R', rCBV, and rOEF were compared between EGFR-amplified and non-amplified gliomas. ROC analysis was performed to assess the ability of imaging characteristics to discriminate EGFR amplification status. Overall survival (OS) was determined using univariate and multivariate cox models. Kaplan-Meier survival curves were plotted and compared using the log-rank test.

Results: EGFR amplified gliomas exhibited significantly higher median R' and rOEF than non-amplified gliomas. ROC analysis suggested that R' (AUC = 0.7190; P = 0.0048) and rOEF (AUC = 0.6959; P = 0.0156) could separate EGFR status. Patients with EGFR-amplified gliomas had a significantly shorter OS than non-amplified patients. Univariate cox regression analysis determined both R' and rOEF significantly influence OS. No significant difference was observed in rCBV between patient cohorts nor was rCBV found to be an effective differentiator of EGFR status.

Conclusion: Imaging of tumor oxygen characteristics revealed EGFR-amplified gliomas to be more hypoxic and contribute to shorter patient survival than EGFR non-amplified gliomas.
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http://dx.doi.org/10.1007/s00234-020-02585-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8071834PMC
June 2021

Maximum Uptake and Hypermetabolic Volume of 18F-FDOPA PET Estimate Molecular Status and Overall Survival in Low-Grade Gliomas: A PET and MRI Study.

Clin Nucl Med 2020 Dec;45(12):e505-e511

Department of Radiological Science, David Geffen School of Medicine.

Purpose: We evaluated F-FDOPA PET and MRI characteristics in association with the molecular status and overall survival (OS) in a large number of low-grade gliomas (LGGs).

Methods: Eighty-six patients who underwent F-FDOPA PET and MRI and were diagnosed with new or recurrent LGGs were retrospectively evaluated with respect to their isocitrate dehydrogenase (IDH) and 1p19q status (10 IDH wild type, 57 mutant, 19 unknown; 1p19q status in IDH mutant: 20 noncodeleted, 37 codeleted). After segmentation of the hyperintense area on fluid-attenuated inversion recovery image (FLAIRROI), the following were calculated: normalized SUVmax (nSUVmax) of F-FDOPA relative to the striatum, F-FDOPA hypermetabolic volume (tumor-to-striatum ratios >1), FLAIRROI volume, relative cerebral blood volume, and apparent diffusion coefficient within FLAIRROI. Receiver operating characteristic curve and Cox regression analyses were performed.

Results: PET and MRI metrics combined with age predicted the IDH mutation and 1p19q codeletion statuses with sensitivities of 73% and 76% and specificities of 100% and 94%, respectively. Significant correlations were found between OS and the IDH mutation status (hazard ratio [HR] = 4.939), nSUVmax (HR = 2.827), F-FDOPA hypermetabolic volume (HR = 1.048), and FLAIRROI volume (HR = 1.006). The nSUVmax (HR = 151.6) for newly diagnosed LGGs and the F-FDOPA hypermetabolic volume (HR = 1.038) for recurrent LGGs demonstrated significant association with OS.

Conclusions: Combining F-FDOPA PET and MRI with age proved useful for predicting the molecular status in patients with LGGs, whereas the nSUVmax and F-FDOPA hypermetabolic volume may be useful for prognostication.
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http://dx.doi.org/10.1097/RLU.0000000000003318DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7950323PMC
December 2020

Compensatory brainstem functional and structural connectivity in patients with degenerative cervical myelopathy by probabilistic tractography and functional MRI.

Brain Res 2020 12 17;1749:147129. Epub 2020 Sep 17.

Dept. of Neurosurgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States. Electronic address:

Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord impairment in adults. Previous supraspinal investigations have primarily focused on cortical changes in this patient population. As the nexus between the brain and the spinal cord, the brainstem has been understudied in patients with DCM. The current study examined the structural and functional connectivity between the brainstem and cortex in DCM patients using probabilistic tractography and resting-state functional MRI. A total of 26 study patients and 32 neurologically intact, healthy volunteers (HCs) participated in this prospective analysis. The study cohort included DCM patients (n = 18), as well as neurologically asymptomatic patients with evidence of cervical spine degenerative changes and spinal cord compression (n = 8). Results of the study demonstrated significant differences in fiber density (FD), fiber cross-section (FDC), and the functional connectivity (FC) between the study cohort and HCs. Through seeding the brainstem, the study cohort showed reductions in FD and FDC along the corticospinal tract, including regions extending through the corona radiata and internal capsule. By correlating FD and FDC with the Neck Disability Index (NDI), and the modified Japanese Orthopaedic Association (mJOA), we identified increasing total volume of projections to the thalamus, basal ganglia, and internal capsule, and increased functional connectivity to visual network and the posterior parietal cortices. These results support our hypothesis that DCM patients tend to have long-term FC reorganization not only localized to sensorimotor regions, but also to regulatory and visual processing regions, designed to ultimately preserve neurological function.
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http://dx.doi.org/10.1016/j.brainres.2020.147129DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606789PMC
December 2020

Multiparametric MR-PET measurements in hypermetabolic regions reflect differences in molecular status and tumor grade in treatment-naïve diffuse gliomas.

J Neurooncol 2020 Sep 14;149(2):337-346. Epub 2020 Sep 14.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, 924 Westwood Blvd, Suite 615, Los Angeles, CA, 90024, USA.

Purpose: To assess whether hypermetabolically-defined regions of interest (ROIs) on 3,4-dihydroxy-6-[18F]-fluoro-L-phenylalanine (FDOPA) positron emission tomography (PET) could be used to evaluate physiological features and whether there are measurable differences between molecular subtypes and tumor grades.

Methods: Sixty-eight treatment-naïve glioma patients who underwent FDOPA PET and magnetic resonance imaging (MRI) were retrospectively included. Fluid-attenuated inversion recovery hyperintense regions (FLAIR) were segmented. FDOPA hypermetabolic regions (FDOPA, tumor-to-striatum ratios > 1) within FLAIR were extracted. Normalized maximum standardized uptake value (nSUV), volume of each ROI, and median relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) within FLAIR or FDOPA were calculated. Imaging metrics were compared using Students t or Mann-Whitney U tests. Area under the curve (AUC) of receiver-operating characteristic curves were used to determine whether imaging metrics within FLAIR or FDOPA can discriminate different molecular statuses or grades.

Results: Using either FLAIR or FDOPA, the nSUV and rCBV were significantly higher and the ADC was lower in isocitrate dehydrogenase (IDH) wild-type than mutant gliomas, and in higher-grade gliomas (HGGs) than lower-grade gliomas (LGGs). The FDOPA volume was significantly higher in 1p19q codeleted than non-codeleted gliomas, and in HGGs than LGGs. Although not significant, imaging metrics extracted by FDOPA discriminated molecular status and tumor grade more accurately than those extracted by FLAIR (AUC of IDH status, 0.87 vs. 0.82; 1p19q status, 0.78 vs. 0.73; grade, 0.87 vs. 0.76).

Conclusion: FDOPA hypermetabolic ROI may extract useful imaging features of gliomas, which can illuminate biological differences between different molecular status or tumor grades.
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http://dx.doi.org/10.1007/s11060-020-03613-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7682113PMC
September 2020

Focal cortical dysplasia imaging discrepancies between MRI and FDG-PET: Unique association with temporal lobe location.

Seizure 2020 Oct 17;81:180-185. Epub 2020 Aug 17.

Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States.

Purpose: Although magnetic resonance imaging (MRI) and F-2-fluorodeoxyglucose-positron emission tomography (FDG-PET) are used for pre-surgical assessment of focal cortical dysplasia (FCD), they often disagree. This study aimed to identify factors that contribute to discrepancies in FCD imaging between MRI and FDG-PET.

Methods: Sixty-two patients (mean age, 18.9 years) with a FCD type I or II were retrospectively selected. These patients were visually categorized into two groups: 1) extent of PET abnormality larger than MRI abnormality and 2) vice versa or equivalent. Predictive factors of these two groups were analyzed by multivariate logistic regression. The extent of hypometabolic transient zone surrounding FCDs and their mean standardized uptake values were measured and compared by the Mann-Whitney U-test.

Results: FCDs were detected on MRI and PET in 46 and 55 patients, respectively, whereas no abnormality was detected in 4 patients. The PET hypometabolic areas were larger than the MRI abnormal areas in 26 patients (88 % in the temporal lobe), whereas the PET hypometabolic areas were equivalent or smaller than the MRI abnormal areas in 32 patients (69 % in the frontal lobe). The temporal lobe location was an independent predictor for differentiating the two groups (OR = 35.2, 95 % CI = 6.81-168.0, P < .001). The temporal lobe lesions had significantly wider transient zones and lower standardized uptake values than those in the other lobes (P < .001, both).

Conclusion: The discrepancies between MRI and FDG-PET findings of FCD were associated with temporal lobe location.
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http://dx.doi.org/10.1016/j.seizure.2020.08.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8216482PMC
October 2020

Leptomeningeal Carcinomatosis of Prostate Cancer: A Case Report and Review of the Literature.

Rev Urol 2020 ;22(2):80-84

Division of Hematology and Oncology, West Los Angeles Veterans Affairs Medical Center Los Angeles, CA.

Leptomeningeal carcinomatosis is a rare complication of prostate cancer. It is likely underdiagnosed as suggested by autopsy studies and is expected to become more prevalent with increasing survival of prostate cancer patients. Prostate cancer leptomeningeal carcinomatosis is associated with rapid functional decline and a median survival of approximately 1 month. Diagnosis is challenging because the clinical manifestations are varied, and no gold-standard diagnostic approach exists. Treatment of prostate cancer leptomeningeal carcinomatosis is not standardized and multiple approaches have been reported, mostly as case studies. Herein we report a case of a 73-year-old patient with metastatic castration-resistant prostate cancer who presented to our clinic with subacute cognitive decline, ataxia, and urinary incontinence, and was found to have leptomeningeal carcinomatosis.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7393686PMC
January 2020

Human IDH mutant 1p/19q co-deleted gliomas have low tumor acidity as evidenced by molecular MRI and PET: a retrospective study.

Sci Rep 2020 07 17;10(1):11922. Epub 2020 Jul 17.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, University of California, Los Angeles, 924 Westwood Blvd., Suite 615, Los Angeles, CA, 90024, USA.

Co-deletion of 1p/19q is a hallmark of oligodendroglioma and predicts better survival. However, little is understood about its metabolic characteristics. In this study, we aimed to explore the extracellular acidity of WHO grade II and III gliomas associated with 1p/19q co-deletion. We included 76 glioma patients who received amine chemical exchange saturation transfer (CEST) imaging at 3 T. Magnetic transfer ratio asymmetry (MTR) at 3.0 ppm was used as the pH-sensitive CEST biomarker, with higher MTR indicating lower pH. To control for the confounder factors, T relaxometry and L-6-F-fluoro-3,4-dihydroxyphenylalnine (F-FDOPA) PET data were collected in a subset of patients. We found a significantly lower MTR in 1p/19q co-deleted gliomas (co-deleted, 1.17% ± 0.32%; non-co-deleted, 1.72% ± 0.41%, P = 1.13 × 10), while FDOPA (P = 0.92) and T (P = 0.61) were not significantly affected. Receiver operating characteristic analysis confirmed that MTR could discriminate co-deletion status with an area under the curve of 0.85. In analysis of covariance, 1p/19q co-deletion status was the only significant contributor to the variability in MTR when controlling for age and FDOPA (P = 2.91 × 10) or T (P = 8.03 × 10). In conclusion, 1p/19q co-deleted gliomas were less acidic, which may be related to better prognosis. Amine CEST-MRI may serve as a non-invasive biomarker for identifying 1p/19q co-deletion status.
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http://dx.doi.org/10.1038/s41598-020-68733-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7367867PMC
July 2020

Reperfusion Into Severely Damaged Brain Tissue Is Associated With Occurrence of Parenchymal Hemorrhage for Acute Ischemic Stroke.

Front Neurol 2020 26;11:586. Epub 2020 Jun 26.

Department of Neurology, USC Stevens Neuroimaging and Informatics Institute, USC, Los Angeles, CA, United States.

This study aims to quantify the reperfusion status within severely damaged brain tissue and to evaluate its relationship with high grade of hemorrhagic transformation (HT). Pseudo-continuous ASL was performed along with DWI in 102 patients within 24 h post-treatments. The infarction core was identified using ADC values <550 × 10 mm/s. CBF within the infarction core and its contralateral counterpart were acquired. CBF at the 25th, median, and 75th percentiles of the contralateral counterpart were used as thresholds and the ASL reperfusion volume above the threshold was labeled as vol-25, -50, and -75, respectively. Recanalization was defined according to Thrombolysis in Myocardial Infarction (TIMI) criteria. Quantified reperfusion within the infarction core differed significantly in patients with complete and incomplete recanalization. In the ROC analysis for the prediction of parenchymal hematoma (PH), ASL reperfusion vol-25 had the highest area under the curve (AUC) when compared with ASL vol-50 and ASL vol-75. ASL reperfusion vol-25 had significantly higher AUC compared with ADC threshold volume in the prediction of PH (0.783 vs. 0.685, = 0.0036) and PH-2 (0.844 vs. 0.754, = 0.0035). In stepwise multivariate logistic regression analysis, only ASL reperfusion vol-25 emerged as an independent predictor of PH (OR = 3.51, 95% CI: 1.65-7.45, < 0.001) and PH-2 (OR = 2.32, 95% CI: 1.13-4.76, = 0.022). Increased reperfusion volume within severely damaged brain tissue is associated with the occurrence of higher grade of HT.
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http://dx.doi.org/10.3389/fneur.2020.00586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7332705PMC
June 2020

Voxelwise and Patientwise Correlation of F-FDOPA PET, Relative Cerebral Blood Volume, and Apparent Diffusion Coefficient in Treatment-Naïve Diffuse Gliomas with Different Molecular Subtypes.

J Nucl Med 2021 03 9;62(3):319-325. Epub 2020 Jul 9.

UCLA Brain Tumor Imaging Laboratory, Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, UCLA, Los Angeles, California

Our purpose was to identify correlations between F-fluorodihydroxyphenylalanine (F-FDOPA) uptake and physiologic MRI, including relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC), in gliomas with different molecular subtypes and to evaluate their prognostic values. Sixty-eight treatment-naïve glioma patients who underwent F-FDOPA PET and physiologic MRI were retrospectively selected (36 with isocitrate dehydrogenase wild-type [IDH], 16 with mutant 1p/19q noncodeleted [IDH], and 16 with mutant codeleted [IDH]). Fluid-attenuated inversion recovery hyperintense areas were segmented and used as regions of interest. For voxelwise and patientwise analyses, Pearson correlation coefficients ( and ) between the normalized SUV (nSUV), rCBV, and ADC were evaluated. Cox regression analysis was performed to investigate the associations between overall survival and , maximum or median nSUV, median rCBV, or median ADC. For IDH and IDH gliomas, nSUV demonstrated significant positive correlations with rCBV ( = 0.25 and 0.31, respectively; = 0.50 and 0.70, respectively) and negative correlations with ADC ( = -0.19 and -0.19, respectively; = -0.58 and -0.61, respectively) in both voxelwise and patientwise analyses. IDH gliomas demonstrated a significant positive correlation between nSUV and ADC only in voxelwise analysis ( = 0.18). In Cox regression analysis, between nSUV and rCBV (hazard ratio, 28.82) or ADC (hazard ratio, 0.085) had significant associations with overall survival for only IDH gliomas. IDH gliomas showed distinctive patterns of correlations between amino acid PET and physiologic MRI. Stronger correlations between nSUV and rCBV or ADC may result in a worse prognosis for IDH gliomas.
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http://dx.doi.org/10.2967/jnumed.120.247411DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8049346PMC
March 2021

Diffusion MRI changes in the anterior subventricular zone following chemoradiation in glioblastoma with posterior ventricular involvement.

J Neurooncol 2020 May 1;147(3):643-652. Epub 2020 Apr 1.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.

Introduction: There is growing evidence that the subventricular zone (SVZ) plays a key role in glioblastoma (GBM) tumorigenesis. However, little is known regarding how the SVZ, which is a harbor for adult neural stem cells, may be influenced by chemoradiation. The current diffusion-weighted imaging (DWI) study explored ipsilateral and contralateral alterations in the anterior SVZ in GBM patients with posterior enhancing lesions following chemoradiation.

Methods: Forty GBM patients with tumor involvement in the posterior SVZ (mean age = 57 ± 10; left-hemisphere N = 25; right-hemisphere N = 15) were evaluated using DWI before and after chemoradiation. Regions-of-interest were drawn on the ipsilesional and contralesional anterior SVZ on apparent diffusion coefficient (ADC) maps for both timepoints. ADC histogram analysis was performed by modeling a bimodal, double Gaussian distribution to obtain ADC, defined as the mean of the lower Gaussian distribution.

Results: The ipsilesional SVZ had lower ADC values compared to the contralesional SVZ before treatment (mean difference = 0.025 μm/ms; P = 0.007). Following chemoradiation, these changes were no longer observed (mean difference = 0.0025 μm/ms; P > 0.5), as ADC values of the ipsilesional SVZ increased (mean difference = 0.026 μm/ms; P = 0.037). An increase in ipsilesional ADC was associated with shorter progression-free (P = 0.0119) and overall survival (P = 0.0265).

Conclusions: These preliminary observations suggest baseline asymmetry as well as asymmetric changes in the SVZ proximal (ipsilesional) to the tumor with respect to contralesional SVZ regions may be present in GBM, potentially implicating this region in tumorigenesis and/or treatment resistance.
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http://dx.doi.org/10.1007/s11060-020-03460-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7769136PMC
May 2020

4D CT Parathyroid for the General Radiologist: A Pictorial Essay of Illustrative Cases.

Curr Probl Diagn Radiol 2020 Feb 29. Epub 2020 Feb 29.

Scripps Physicians Medical Group, Diagnostic Neuroradiology, San Diego, CA.

Primary hyperparathyroidism is a morbid disease that affects multiple organ systems and causes a multitude of debilitating symptoms if not properly diagnosed and treated. Minimally invasive parathyroidectomy is now the standard of care for the treatment of primary hyperparathyroidism. In the hands of experienced high-volume surgeons, the success rate of this treatment is approximately 95%. Preoperative planning with 4-dimensional computed tomography (4DCT) is becoming increasingly common as a first line imaging modality. It is important for general radiologists to become familiar with this type of study in order to better assist their surgical colleagues. This image-rich review will discuss hyperparathyroidism, benefits, and weaknesses of different imaging modalities, 4DCT imaging protocol, relevant anatomy, expected appearance, and location of parathyroid adenomas, ectopic and atypical appearances, multigland disease and important mimics.
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http://dx.doi.org/10.1067/j.cpradiol.2020.02.012DOI Listing
February 2020

Evaluating Radiology Result Communication in the Emergency Department.

Can Assoc Radiol J 2021 Nov 17;72(4):846-853. Epub 2020 Feb 17.

Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada.

Purpose: To assess the pattern of result communication that occurs between radiologists and referring physicians in the emergency department setting.

Methods: An institutional review board-approved prospective study was performed at a large academic medical center with 24/7 emergency radiology cover. Emergency radiologists logged information regarding all result-reporting communication events that occurred over a 168-hour period.

Results: A total of 286 independent result communication events occurred during the study period, the vast majority of which occurred via telephone (232/286). Emergency radiologists spent 10% of their working time communicating results. Similar amounts of time were spent discussing negative and positive cross-sectional imaging examinations. In a small minority of communication events, additional information was gathered through communication that resulted in a change of interpretation from a normal to an abnormal study.

Conclusions: Effective and efficient result communication is critical to care delivery in the emergency department setting. Discussion regarding abnormal cases, both in person and over the phone, is encouraged. However, in the emergency setting, time spent on routine direct communication of negative examination results in advance of the final report may lead to increased disruptions, longer turnaround times, and negatively impact patient care. In very few instances, does the additional information gained from the communication event result in a change of interpretation?
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http://dx.doi.org/10.1177/0846537119899268DOI Listing
November 2021
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