Brain Tumor Recurrence vs. Radiation Necrosis Classification and Patient Survivability Prediction.

GB (Glioblastoma WHO Grade 4) is the most aggressive type of brain tumor in adults that has a short survival rate even after aggressive treatment with surgery and radiation therapy. The changes in magnetic resonance imaging (MRI) for patients with GB after radiotherapy are indicative of either radiation-induced necrosis (RN) or recurrent brain tumor (rBT). Screening for rBT and RN at an early stage is crucial for facilitating faster treatment and better outcomes for the patients. Differentiating rBT from RN is challenging as both may present with similar radiological and clinical characteristics on MRI. Moreover, learning-based rBT versus RN classification using MRI may suffer from class imbalance due to a lack of patient data. While synthetic data generation using generative models has shown promise to address class imbalances, the underlying data representation may be different in synthetic or augmented data. This study proposes computational modeling with statistically rigorous repeated random sub-sampling to balance the subset sample size for rBT and RN classification. The proposed pipeline includes multiresolution radiomic feature (MRF) extraction followed by feature selection with statistical significance testing (p<0.05). The five-fold cross validation results show the proposed model with MRF features classifies rBT from RN with an area under the curve (AUC) of 0.892±0.055. Moreover, considering the dependence between survival time and censoring time (where patients are not followed up until death), the feasibility of using MRF radiomic features as a non-invasive biomarker to identify patients who are at higher risk of recurrence or radiation necrosis is demonstrated. The cross-validated results show that the MRF model provides the best overall survival prediction with an AUC of 0.77±0.032. Comparison with state-of-the-art methods suggest the proposed method is effective in RN versus rBT classification and patient survivability prediction.

Recommended Resting-State fMRI Acquisition and Preprocessing Steps for Preoperative Mapping of Language and Motor and Visual Areas in Adult and Pediatric Patients with Brain Tumors and Epilepsy.

Resting-state (rs) fMRI has been shown to be useful for preoperative mapping of functional areas in patients with brain tumors and epilepsy. However, its lack of standardization limits its widespread use and hinders multicenter collaboration. The American Society of Functional Neuroradiology, American Society of Pediatric Neuroradiology, and the American Society of Neuroradiology Functional and Diffusion MR Imaging Study Group recommend specific rs-fMRI acquisition approaches and preprocessing steps that will further support rs-fMRI for future clinical use. A task force with expertise in fMRI from multiple institutions provided recommendations on the rs-fMRI steps needed for mapping of language, motor, and visual areas in adult and pediatric patients with brain tumor and epilepsy. These were based on an extensive literature review and expert consensus.Following rs-fMRI acquisition parameters are recommended: minimum 6-minute acquisition time; scan with eyes open with fixation; obtain rs-fMRI before both task-based fMRI and contrast administration; temporal resolution of ≤2 seconds; scanner field strength of 3T or higher. The following rs-fMRI preprocessing steps and parameters are recommended: motion correction (seed-based correlation analysis [SBC], independent component analysis [ICA]); despiking (SBC); volume censoring (SBC, ICA); nuisance regression of CSF and white matter signals (SBC); head motion regression (SBC, ICA); bandpass filtering (SBC, ICA); and spatial smoothing with a kernel size that is twice the effective voxel size (SBC, ICA).The consensus recommendations put forth for rs-fMRI acquisition and preprocessing steps will aid in standardization of practice and guide rs-fMRI program development across institutions. Standardized rs-fMRI protocols and processing pipelines are essential for multicenter trials and to implement rs-fMRI as part of standard clinical practice.

Neuroaxial Infantile Hemangiomas: Imaging Manifestations and Association with Hemangioma Syndromes.

BACKGROUND AND PURPOSE: Infantile hemangiomas are common lesions in the pediatric population; in rare cases, an infantile hemangioma can be detected along the neural axis. The purposes of our study included determination of the incidence, location, and imaging appearance of neuroaxial infantile hemangiomas and their syndromic association. We also assessed additional features of cerebral and cardiovascular anomalies that may be associated with neuroaxial lesions. MATERIALS AND METHODS: A retrospective cohort study was performed, searching the radiology database for patients with segmental infantile hemangiomas referred for assessment of possible hemangioma syndromes. We retrospectively reviewed brain and spine MR imaging studies, with particular attention paid to neuroaxial vascular lesions, as well as the relevant clinical data. Neuroaxial hemangioma imaging findings were described, and comparison of segmental cutaneous infantile hemangioma location with the imaging findings was performed in patients with confirmed hemangioma syndromes and in patients with isolated skin infantile hemangioma. RESULTS: Ninety-five patients with segmental infantile hemangioma were included in the study, 42 of whom had a hemangioma syndrome; of those, 41 had posterior fossa brain malformations, hemangioma, arterial lesions, cardiac abnormalities, and eye abnormalities (PHACE) syndrome and 1 had diffuse neonatal hemangiomatosis. Neuroaxial involvement was detected in 20/42 patients (48%) with hemangioma syndromes and in no subjects with isolated segmental infantile hemangioma (P < .001). The most common intracranial hemangioma location was within the ipsilateral internal auditory canal (83%). CONCLUSIONS: Many pediatric patients with segmental infantile hemangioma in the setting of hemangioma syndromes, especially those with PHACE, had neuroaxial hemangiomas. This finding may potentially lead to requiring additional clinical evaluation and management of these patients.

A Diagnostic Algorithm for Posterior Fossa Tumors in Children: A Validation Study.

BACKGROUND AND PURPOSE: Primary posterior fossa tumors comprise a large group of neoplasias with variable aggressiveness and short and long-term outcomes. This study aimed to validate the clinical usefulness of a radiologic decision flow chart based on previously published neuroradiologic knowledge for the diagnosis of posterior fossa tumors in children. MATERIALS AND METHODS: A retrospective study was conducted (from January 2013 to October 2019) at 2 pediatric referral centers, Children's Hospital of Philadelphia, United States, and Great Ormond Street Hospital, United Kingdom. Inclusion criteria were younger than 18 years of age and histologically and molecularly confirmed posterior fossa tumors. Subjects with no available preoperative MR imaging and tumors located primarily in the brain stem were excluded. Imaging characteristics of the tumors were evaluated following a predesigned, step-by-step flow chart. Agreement between readers was tested with the Cohen κ, and each diagnosis was analyzed for accuracy. RESULTS: A total of 148 cases were included, with a median age of 3.4 years (interquartile range, 2.1-6.1 years), and a male/female ratio of 1.24. The predesigned flow chart facilitated identification of pilocytic astrocytoma, ependymoma, and medulloblastoma sonic hedgehog tumors with high sensitivity and specificity. On the basis of the results, the flow chart was adjusted so that it would also be able to better discriminate atypical teratoid/rhabdoid tumors and medulloblastoma groups 3 or 4 (sensitivity = 75%-79%; specificity = 92%-99%). Moreover, our adjusted flow chart was useful in ruling out ependymoma, pilocytic astrocytomas, and medulloblastoma sonic hedgehog tumors. CONCLUSIONS: The modified flow chart offers a structured tool to aid in the adjunct diagnosis of pediatric posterior fossa tumors. Our results also establish a useful starting point for prospective clinical studies and for the development of automated algorithms, which may provide precise and adequate diagnostic tools for these tumors in clinical practice.

Arterial Spin-Labeling Perfusion for PHACE Syndrome.

BACKGROUND AND PURPOSE: Arterial stroke is a rare-but-reported complication in patients with posterior fossa brain malformations, hemangiomas, arterial anomalies, coarctation of the aorta and cardiac defects, and eye abnormalities (PHACE) syndrome. Currently, stroke risk is inferred by the severity of arterial anomalies identified on MRA, though no evidenced-based data exist. The purpose of our study was to determine whether arterial spin-labeling MR imaging perfusion can detect alterations in CBF in patients with PHACE syndrome. MATERIALS AND METHODS: Records were reviewed from 3 institutions for all patients with PHACE syndrome who underwent arterial spin-labeling from 2000 to 2019. CBF was qualitatively investigated with arterial spin-labeling to determine whether there was decreased or normal perfusion. Arterial anomalies were characterized on MRA imaging, and parenchymal brain findings were evaluated on conventional MR imaging sequences. RESULTS: Forty-one patients with PHACE syndrome had arterial spin-labeling imaging. There were 30 females and 11 males (age range, 7 days to 15 years). Of the 41 patients, 10 (24%) had decreased CBF signal corresponding to a major arterial territory. Ten of 10 patients had decreased CBF signal in the anterior circulation, 2/10 had decreased anterior and posterior circulation CBF signal, 2/10 had decreased bilateral anterior circulation CBF signal, and 1/10 had globally decreased CBF signal. Forty of 41 (97.5%) patients had at least 1 arteriopathy, and in those with decreased CBF signal, the arteriopathy corresponded to the CBF signal alteration in 10/10 patients. CONCLUSIONS: Arterial spin-labeling can potentially characterize hemodynamic changes in patients with PHACE syndrome.

High accuracy of arterial spin labeling perfusion imaging in differentiation of pilomyxoid from pilocytic astrocytoma.

INTRODUCTION: Pilomyxoid astrocytoma (PMA) is a relatively new tumor entity which has been added to the 2007 WHO Classification of tumors of the central nervous system. The goal of this study is to utilize arterial spin labeling (ASL) perfusion imaging to differentiate PMA from pilocytic astrocytoma (PA). METHODS: Pulsed ASL and conventional MRI sequences of patients with PMA and PA in the past 5 years were retrospectively evaluated. Patients with history of radiation or treatment with anti-angiogenic drugs were excluded. RESULTS: A total of 24 patients (9 PMA, 15 PA) were included. There were statistically significant differences between PMA and PA in mean tumor/gray matter (GM) cerebral blood flow (CBF) ratios (1.3 vs 0.4, p < 0.001) and maximum tumor/GM CBF ratio (2.3 vs 1, p < 0.001). Area under the receiver operating characteristic (ROC) curves for differentiation of PMA from PA was 0.91 using mean tumor CBF, 0.95 using mean tumor/GM CBF ratios, and 0.89 using maximum tumor/GM CBF. Using a threshold value of 0.91, the mean tumor/GM CBF ratio was able to diagnose PMA with 77 % sensitivity, 100 % specificity, and a threshold value of 0.7, provided 88 % sensitivity and 86 % specificity. There was no statistically significant difference between the two tumors in enhancement pattern (p = 0.33), internal architecture (p = 0.15), or apparent diffusion coefficient (ADC) values (p = 0.07). CONCLUSION: ASL imaging has high accuracy in differentiating PMA from PA. The result of this study may have important applications in prognostication and treatment planning especially in patients with less accessible tumors such as hypothalamic-chiasmatic gliomas.

Correlation of prenatal and postnatal MRI findings in schizencephaly.

BACKGROUND AND PURPOSE: Schizencephaly is a rare malformation of the brain characterized by a gray matter-lined defect extending from the pial surface to the lateral ventricles. The purpose of this study was to correlate imaging findings of schizencephaly and associated anomalies on fetal and postnatal MR imaging and assess possible changes that may occur from the prenatal-to-postnatal state. MATERIALS AND METHODS: A retrospective review of subjects with schizencephaly who had both pre- and postnatal MR imaging was performed. Subject age, cleft type, number, location, and features of the defects and associated anomalies were recorded. Normalized dimensions of the defect and ipsilateral ventricle were measured and correlated to changes in the clefts between pre- and postnatal imaging. RESULTS: Ten subjects with 18 clefts (8 bilateral) were included. Most defects (83%) were open on prenatal MR imaging, but 47% of those were found to have subsequently closed on postnatal imaging. Evidence of prior hemorrhage was seen in 83%. Prenatal MR imaging detected all cases of an absent septum pellucidum but detected a fraction of gross polymicrogyria and missed all cases of optic nerve hypoplasia. The normalized ipsilateral ventricular and inner and middle width dimensions of the defects were significantly decreased at postnatal imaging (P < .05). The widths of the defects, ventricular width, and presence of hemorrhage were not predictors of closure of prenatally diagnosed open defects (P > .05). CONCLUSIONS: In our series, nearly half of prenatally open schizencephaly defects had closed on postnatal imaging. Prenatal MR imaging was only able to demonstrate some of the associated anomalies.

CT and MRI of pediatric skull lesions with fluid-fluid levels.

Fluid-fluid levels can occur whenever different fluid densities are contained within a cystic or compartmentalized lesion, usually related to the evolution of hematoma or necrosis. Review of the literature demonstrated that throughout the skeletal system, the most common etiology for fluid-fluid levels is aneurysmal bone cyst, but there are no dedicated studies of the pediatric calvaria, to our knowledge. In this report, we present clinicopathologic characteristics and CT and MR imaging of 11 patients with pediatric skull mass lesions demonstrating fluid-fluid levels. MR imaging demonstrated more fluid-fluid levels compared with CT in all cases. The etiologies of skull lesions with fluid-fluid levels were Langerhans cell histiocytosis in 4 (36.6%), aneurysmal bone cysts in 3 (27.2%), cephalohematoma in 3 (27.2%), and metastatic neuroblastoma in 1 (9%). Radiologists should be aware of the other etiologies of calvarial lesions with fluid-fluid levels in the pediatric skull.

Preoperative angiography and external carotid artery embolization of juvenile nasopharyngeal angiofibromas in a tertiary referral paediatric centre.

AIM: To evaluate the relationship between intraoperative blood loss and juvenile nasopharyngeal angiofibroma (JNA) vascular supply and tumour stage in patients who underwent superselective external carotid artery (ECA) embolization. This series is unique in that all embolizations were performed by dedicated paediatric interventional radiologists at a tertiary referral paediatric centre. MATERIALS AND METHODS: Seventeen male patients treated from January 2002 to August 2009 underwent preoperative angiography and embolization using polyvinyl alcohol (PVA) particles. Tumours were graded using three different staging systems based on preoperative imaging and correlated to surgical blood loss. All patients underwent bilateral internal and external carotid angiography, with embolization of ECA tumour supply via microcatheter delivery of PVA particles. Particle size ranged from 150-500 µm with a mean size of 250-355 µm. Surgical resection was performed with either endoscopic or open techniques within 24 h and intraoperative blood loss was reported. RESULTS: Seven lesions were supplied strictly by the ECA circulation and had mean surgical blood loss of 336 ml. Twelve lesions had both ECA and internal carotid artery (ICA) supply and had mean surgical blood loss of 842 ml. The difference in blood loss in these two groups was statistically significant (p = 0.03). There was no case of inadvertent intracranial or ophthalmic embolization. There were statistically significant correlations between estimated surgical blood loss and the Andrews (p = 0.008), Radkowski (p = 0.015), and University of Pittsburgh Medical Center (UPMC; p = 0.015) preoperative tumour staging systems, respectively. CONCLUSION: Preoperative embolization of JNA tumours can be safely performed without neurological complications. The present study identified a statistically significant difference in intraoperative blood loss between those lesions with a purely ECA vascular supply and a combination of ECA and ICA vascular supply. Angiography is helpful in delineating ICA supply and can help guide surgical planning.

Differentiation between oligodendroglioma genotypes using dynamic susceptibility contrast perfusion-weighted imaging and proton MR spectroscopy.

BACKGROUND AND PURPOSE: Oligodendrogliomas with 1p/19q chromosome LOH are more sensitive to chemoradiation therapy than those with intact alleles. The usefulness of dynamic susceptibility contrast-PWI-guided ¹H-MRS in differentiating these 2 genotypes was tested in this study. MATERIALS AND METHODS: Forty patients with oligodendrogliomas, 1p/19q LOH (n = 23) and intact alleles (n = 17), underwent MR imaging and 2D-¹H-MRS. ¹H-MRS VOI was overlaid on FLAIR images to encompass the hyperintense abnormality on the largest cross-section of the neoplasm and then overlaid on CBV maps to coregister CBV maps with ¹H-MRS VOI. rCBVmax values were obtained by measuring the CBV from each of the selected ¹H-MRS voxels in the neoplasm and were normalized with respect to contralateral white matter. Metabolite ratios with respect to ipsilateral Cr were computed from the voxel corresponding to the rCBVmax value. Logistic regression and receiver operating characteristic analyses were performed to ascertain the best model to discriminate the 2 genotypes of oligodendrogliomas. Qualitative evaluation of conventional MR imaging characteristics (patterns of tumor border, signal intensity, contrast enhancement, and paramagnetic susceptibility effect) was also performed to distinguish the 2 groups of oligodendrogliomas. RESULTS: The incorporation of rCBVmax value and metabolite ratios (NAA/Cr, Cho/Cr, Glx/Cr, myo-inositol/Cr, and lipid + lactate/Cr) into the multivariate logistic regression model provided the best discriminatory classification with sensitivity (82.6%), specificity (64.7%), and accuracy (72%) in distinguishing 2 oligodendroglioma genotypes. Oligodendrogliomas with 1p/19q LOH were also more associated with paramagnetic susceptibility effect (P < .05). CONCLUSIONS: Our preliminary results indicate the potential of combing PWI and ¹H-MRS to distinguish oligodendroglial genotypes.

Differentiation between glioblastomas, solitary brain metastases, and primary cerebral lymphomas using diffusion tensor and dynamic susceptibility contrast-enhanced MR imaging.

BACKGROUND AND PURPOSE: Glioblastomas, brain metastases, and PCLs may have similar enhancement patterns on MR imaging, making the differential diagnosis difficult or even impossible. The purpose of this study was to determine whether a combination of DTI and DSC can assist in the differentiation of glioblastomas, solitary brain metastases, and PCLs. MATERIALS AND METHODS: Twenty-six glioblastomas, 25 brain metastases, and 16 PCLs were retrospectively identified. DTI metrics, including FA, ADC, CL, CP, CS, and rCBV were measured from the enhancing, immediate peritumoral and distant peritumoral regions. A 2-level decision tree was designed, and a multivariate logistic regression analysis was used at each level to determine the best model for classification. RESULTS: From the enhancing region, significantly elevated FA, CL, and CP and decreased CS values were observed in glioblastomas compared with brain metastases and PCLs (P < .001), whereas ADC, rCBV, and rCBV(max) values of glioblastomas were significantly higher than those of PCLs (P < .01). The best model to distinguish glioblastomas from nonglioblastomas consisted of ADC, CS (or FA) from the enhancing region, and rCBV from the immediate peritumoral region, resulting in AUC = 0.938. The best predictor to differentiate PCLs from brain metastases comprised ADC from the enhancing region and CP from the immediate peritumoral region with AUC = 0.909. CONCLUSIONS: The combination of DTI metrics and rCBV measurement can help in the differentiation of glioblastomas from brain metastases and PCLs.

Operative treatment of renal autonomous hyperparathyroidism: cause of persistent or recurrent disease in 304 patients.

BACKGROUND: Subtotal parathyroidectomy (SPTX) and total parathyroidectomy with autotransplantation (TPTX and AT) are standard procedures in the treatment of renal autonomous hyperparathyroidism. In contrast to primary hyperparathyroidism, the persistence/recurrence rate is reported of up to 12.0%. PATIENTS AND METHODS: Between 1986 and 2000 we operated on 304 patients with renal autonomous hyperparathyroidism including 14 patients who were admitted after a primary operation in an outside hospital. Mean observation period was 51.4+/-38.9 months. RESULTS: The overall persistence/recurrence rate in our patients was 9.0% (26/290). After SPTX, excluding patients with an incomplete operation, it was 3.7%, and after TPTX and AT it was 6.0%. Reasons for developing recurrent or persistent disease in these patients were removal of less than 3.5 glands ( n=12), hyperplastic autograft ( n=5), and supernumerary gland ( n=4). After the first reoperation 7 patients (26.9%) had persistent or recurrent disease. CONCLUSIONS: An incomplete primary operation caused by missed cervical glands was the major reason for persistent ( n=8) or recurrent ( n=4) disease after different operative strategies in renal autonomous hyperparathyroidism.