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Open Access Publications from the University of California

Scholarly Works (15 results)

  • Article
  • Peer Reviewed
UC San Francisco Previously Published Works (2020)
The olfactory bulbs and tracts are central nervous system white matter tracts maintained by central neuroglia. Although rare, gliomas can originate from and progress to involve the olfactory apparatus. Through a Health Insurance Portability and Accountability Act-compliant retrospective review of the institutional teaching files and brain MR imaging reports spanning 10 years, we identified 12 cases of gliomas involving the olfactory bulbs and tracts, including 6 cases of glioblastoma, 2 cases of anaplastic oligodendroglioma, and 1 case each of pilocytic astrocytoma, diffuse (grade II) astrocytoma, anaplastic astrocytoma (grade III), and diffuse midline glioma. All except the pilocytic astrocytoma occurred in patients with known primary glial tumors elsewhere. Imaging findings of olfactory tumor involvement ranged from well-demarcated enhancing masses to ill-defined enhancing infiltrative lesions to nonenhancing masslike FLAIR signal abnormality within the olfactory tracts. Familiarity with the imaging findings of glioma involvement of the olfactory nerves is important for timely diagnosis and treatment of recurrent gliomas and to distinguish them from other disease processes.
    Cover page: Involvement of the Olfactory Apparatus by Gliomas
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2017)

    Background and purpose

    The 2016 World Health Organization Classification of Tumors of the Central Nervous System includes "diffuse midline glioma with histone H3 K27M mutation" as a new diagnostic entity. We describe the MR imaging characteristics of this new tumor entity in pediatric patients.

    Materials and methods

    We retrospectively reviewed imaging features of pediatric patients with midline gliomas with or without the histone H3 K27 mutation. We evaluated the imaging features of these tumors on the basis of location, enhancement pattern, and necrosis.

    Results

    Among 33 patients with diffuse midline gliomas, histone H3 K27M mutation was present in 24 patients (72.7%) and absent in 9 (27.3%). Of the tumors, 27.3% (n = 9) were located in the thalamus; 42.4% (n = 14), in the pons; 15% (n = 5), within the vermis/fourth ventricle; and 6% (n = 2), in the spinal cord. The radiographic features of diffuse midline gliomas with histone H3 K27M mutation were highly variable, ranging from expansile masses without enhancement or necrosis with large areas of surrounding infiltrative growth to peripherally enhancing masses with central necrosis with significant mass effect but little surrounding T2/FLAIR hyperintensity. When we compared diffuse midline gliomas on the basis of the presence or absence of histone H3 K27M mutation, there was no significant correlation between enhancement or border characteristics, infiltrative appearance, or presence of edema.

    Conclusions

    We describe, for the first time, the MR imaging features of pediatric diffuse midline gliomas with histone H3 K27M mutation. Similar to the heterogeneous histologic features among these tumors, they also have a diverse imaging appearance without distinguishing features from histone H3 wildtype diffuse gliomas.
      Cover page: Imaging Characteristics of Pediatric Diffuse Midline Gliomas with Histone H3 K27M Mutation
      • Article
      • Peer Reviewed
      UC San Francisco Previously Published Works (2015)
      Malignant gliomas are characterized by infiltrative growth of tumor cells, including along white matter tracts. This may result in clinical cranial neuropathy due to direct involvement of a cranial nerve rather than by leptomeningeal spread along cranial nerves. Gliomas directly involving cranial nerves III-XII are rare, with only 11 cases reported in the literature before 2014, including 8 with imaging. We present 8 additional cases demonstrating direct infiltration of a cranial nerve by a glioma. Asymmetric cisternal nerve expansion compared with the contralateral nerve was noted with a mean length of involvement of 9.4 mm. Based on our case series, the key imaging feature for recognizing direct cranial nerve involvement by a glioma is the detection of an intra-axial mass in the pons or midbrain that is directly associated with expansion, signal abnormality, and/or enhancement of the adjacent cranial nerves.
        Cover page: Direct Cranial Nerve Involvement by Gliomas: Case Series and Review of the Literature
        • Article
        • Peer Reviewed
        UC San Francisco Previously Published Works (2013)

        Background and purpose

        ADC derived from DWI has been shown to correlate with PFS and OS in immunocompetent patients with PCNSL. The purpose of our study was to confirm the validity of ADC measurements as a prognostic biomarker and to determine whether rCBV measurements derived from DSC perfusion MR imaging provide prognostic information.

        Materials and methods

        Pretherapy baseline DWI and DSC perfusion MR imaging in 25 patients with PCNSL was analyzed before methotrexate-based induction chemotherapy. Contrast-enhancing tumor was segmented and coregistered with ADC and rCBV maps, and mean and minimum values were measured. Patients were separated into high or low ADC groups on the basis of previously published threshold values of ADC(min) < 384 × 10(-6) mm(2)/s. High and low rCBV groups were defined on the basis of receiver operating curve analysis. High and low ADC and rCBV groups were analyzed independently and in combination. Multivariate Cox survival analysis was performed.

        Results

        Patients with ADC(min) values < 384 × 10(-6) mm(2)/s or rCBV(mean) values < 1.43 had worse PFS and OS. The patient cohort with combined low ADC(min)-low rCBV(mean) had the worst prognosis. No other variables besides ADC and rCBV significantly affected survival.

        Conclusions

        Our study reinforces the validity of ADC values as a prognostic biomarker and provides the first evidence of low tumor rCBV as a novel risk factor for adverse prognosis in immunocompetent patients with PCNSL.
          Cover page: Combined Diffusion and Perfusion MR Imaging as Biomarkers of Prognosis in Immunocompetent Patients with Primary Central Nervous System Lymphoma
          • Article
          • Peer Reviewed
          UC San Francisco Previously Published Works (2016)

          Background and purpose

          CXC chemokine ligand 13 and interleukin 10 have emerged as CSF biomarkers for the diagnosis of CNS lymphoma. Our hypothesis is that the combined use of ADC, CXC chemokine ligand 13, and interleukin 10 will result in increased diagnostic performance compared with the use of ADC values alone.

          Materials and methods

          Eighty-seven patients were included in this study, including 43 with CNS lymphoma and 44 without CNS lymphoma (21 metastases, 14 high-grade gliomas, 9 tumefactive demyelinating lesions) who had undergone CSF proteomic analysis and had a new enhancing mass on brain MR imaging. Average ADC was derived by contouring the contrast-enhancing tumor volume. Group means were compared via t tests for average ADC, CXC chemokine ligand 13, and interleukin 10. Receiver operating characteristic analysis was performed for each individual variable. Multiple-variable logistic regression with receiver operating characteristic analysis was performed, and the multiple-variable receiver operating characteristic was compared with single-variable receiver operating characteristics.

          Results

          The average ADC was lower and CSF CXC chemokine ligand 13 and interleukin 10 values were higher in CNS lymphoma (P < .001). Areas under the curve ranged from 0.739 to 0.832 for single-variable ROC. Multiple-variable logistic regression yielded statistically significant individual effects for all 3 variables in a combined model. Multiple-variable receiver operating characteristics (area under the curve, 0.928) demonstrated statistically significantly superior diagnostic performance compared with the use of single variables alone.

          Conclusions

          The combined use of ADC, CSF CXC chemokine ligand 13, and interleukin 10 results in increased diagnostic performance for the diagnosis of CNS lymphoma. This finding highlights the importance of CSF analysis when the diagnosis of CNS lymphoma is considered on the basis of MR imaging.
            Cover page: The Combined Performance of ADC, CSF CXC Chemokine Ligand 13, and CSF Interleukin 10 in the Diagnosis of Central Nervous System Lymphoma
            • Article
            • Peer Reviewed
            UC San Francisco Previously Published Works (2007)

            BACKGROUND AND PURPOSE: Embolization of meningiomas has emerged as a preoperative adjuvant therapy that has proved effective in mitigating blood loss during surgical resection. Arterial supply to these tumors is typically identified by diffuse areas of parenchymal staining after selective x-ray angiograms. We investigate the benefits that selective injection of MR contrast may have in identifying vascular territories and determining the effects of embolization therapy.

            MATERIALS AND METHODS: Selective intra-arterial (IA) injection of dilute MR contrast media was used to assess the vascular distribution territories of meningeal tumors before and after embolization therapy. Regions of the tumor that experienced loss of signal intensity after localized contrast injections into the external and common carotid as well as vertebral arteries were used to quantify the specific vessel's volume of distribution. Assessments were made before and after embolization to reveal changes in the vascular supply of the tumor. MR findings were compared with radiographic evaluation of tumor vascular supply on the basis of conventional x-ray angiography.

            RESULTS: MR proved to be an excellent means to assess tissue fed by selected arteries and clearly demonstrated the treated and untreated portions of the neoplasm after therapy. In some instances, MR revealed postembolization residual enhancement of the tumor that was difficult to appreciate on x-ray angiograms. Very low contrast dose was necessary, which made repeated assessment during therapy practical.

            CONCLUSION: MR perfusion imaging with selective IA injection of dilute contrast can reveal the distribution territory of vessels. Changes in tumor vasculature could be detected after embolization, which reveal the volumetric fraction of the tumor affected by the therapy.

              Cover page: Assessment of vasculature of meningiomas and the effects of embolization with intra-arterial MR perfusion imaging: A feasibility study
              • Article
              • Peer Reviewed
              UC San Francisco Previously Published Works (2017)

              Background and purpose

              Cerebral edema associated with brain tumors is an important source of morbidity. Its type depends largely on the capillary ultra-structures of the histopathologic subtype of underlying brain tumor. The purpose of our study was to differentiate vasogenic edema associated with brain metastases and infiltrative edema related to diffuse gliomas using quantitative 3D T1 rho (T1ρ) imaging.

              Materials and methods

              Preoperative MR examination including whole brain 3D T1ρ imaging was performed in 23 patients with newly diagnosed brain tumors (9 with metastasis, 8 with lower grade glioma, LGG, 6 with glioblastoma, GBM). Mean T1ρ values were measured in regions of peritumoral non-enhancing T2 signal hyperintensity, excluding both enhancing and necrotic or cystic component, and normal-appearing white matter.

              Results

              Mean T1ρ values were significantly elevated in the vasogenic edema surrounding intracranial metastases when compared to the infiltrative edema associated with either LGG or GBM (p=0.02 and <0.01, respectively). No significant difference was noted between T1ρ values of infiltrative edema between LGG and GBM (p=0.84 and 0.96, respectively).

              Conclusion

              Our study demonstrates the feasibility and potential diagnostic role of T1ρ in the quantitative differentiation between edema related to intracranial metastases and gliomas and as a potentially complementary tool to standard MR techniques in further characterizing pathophysiology of vasogenic and infiltrative edema.
                Cover page: Differentiation of brain tumor-related edema based on 3D T1rho imaging
                • Article
                • Peer Reviewed
                UC San Francisco Previously Published Works (2013)

                Background and purpose

                Super-resolution track density imaging generates anatomic images with submillimeter voxel resolution by using high-angular-resolution diffusion imaging and fiber-tractography. TDI within the diseased human brain has not been previously described. The purpose of this study was to correlate TDI with histopathologic features of GBM.

                Materials and methods

                A total of 43 tumor specimens (24 contrast-enhancing, 12 NE, and 7 centrally necrotic regions) were collected from 18 patients with treatment-naïve GBM by use of MR imaging-guided neurosurgical techniques. Immunohistochemical stains were used to evaluate the following histopathologic features: hypoxia, architectural disruption, microvascular hyperplasia, and cellular proliferation. We reconstructed track density maps at a 0.25-mm isotropic spatial resolution by using probabilistic streamline tractography combined with constrained spheric deconvolution (model order, 8; 0.1-mm step size; 1 million seed points). Track density values were obtained from each tissue site. A P value of .05 was considered significant and was adjusted for multiple comparisons by use of the false discovery rate method.

                Results

                Track density was not significantly different between contrast-enhancing and NE regions but was more likely to be elevated within regions demonstrating aggressive histopathologic features (P < .05). Significant correlation between relative track density and hypoxia (odds ratio, 3.52; P = .01), architectural disruption (odds ratio, 3.49; P = .03), and cellular proliferation (odds ratio, 1.70; P = .05) was observed irrespective of the presence or absence of contrast enhancement.

                Conclusions

                Numeric values of track density correlate with GBM biologic features and may be clinically useful for identification of regions of tumor infiltration within both enhancing and NE components of GBM.
                  Cover page: Super-Resolution Track Density Imaging of Glioblastoma: Histopathologic Correlation
                  • Article
                  • Peer Reviewed
                  UC San Francisco Previously Published Works (2021)

                  Background and purpose

                  Isocitrate dehydrogenase (IDH) wild-type lower-grade gliomas (histologic grades II and III) with epidermal growth factor receptor (EGFR) amplification or telomerase reverse transcriptase (TERT) promoter mutation are reported to behave similar to glioblastoma. We aimed to evaluate whether MR imaging features could identify a subset of IDH wild-type lower-grade gliomas that carry molecular features of glioblastoma.

                  Materials and methods

                  In this multi-institutional retrospective study, pathologically confirmed IDH wild-type lower-grade gliomas from 2 tertiary institutions and The Cancer Genome Atlas constituted the training set (institution 1 and The Cancer Genome Atlas, 64 patients) and the independent test set (institution 2, 57 patients). Preoperative MRIs were analyzed using the Visually AcceSAble Rembrandt Images and radiomics. The molecular glioblastoma status was determined on the basis of the presence of EGFR amplification and TERT promoter mutation. Molecular glioblastoma was present in 73.4% and 56.1% in the training and test sets, respectively. Models using clinical, Visually AcceSAble Rembrandt Images, and radiomic features were built to predict the molecular glioblastoma status in the training set; then they were validated in the test set.

                  Results

                  In the test set, a model using both Visually AcceSAble Rembrandt Images and radiomic features showed superior predictive performance (area under the curve = 0.854) than that with only clinical features or Visually AcceSAble Rembrandt Images (areas under the curve = 0.514 and 0.648, respectively; P < . 001, both). When both Visually AcceSAble Rembrandt Images and radiomics were added to clinical features, the predictive performance significantly increased (areas under the curve = 0.514 versus 0.863, P < .001).

                  Conclusions

                  MR imaging features integrated with machine learning classifiers may predict a subset of IDH wild-type lower-grade gliomas that carry molecular features of glioblastoma.
                    Cover page: MRI Features May Predict Molecular Features of Glioblastoma in Isocitrate Dehydrogenase Wild-Type Lower-Grade Gliomas
                    • Article
                    • Peer Reviewed
                    UC San Francisco Previously Published Works (2016)
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