Two is better than one: longitudinal detection and volumetric evaluation of brain metastases after Stereotactic Radiosurgery with a deep learning pipeline.

PURPOSE: Close MRI surveillance of patients with brain metastases following Stereotactic Radiosurgery (SRS) treatment is essential for assessing treatment response and the current disease status in the brain. This follow-up necessitates the comparison of target lesion sizes in pre- (prior) and post-SRS treatment (current) T1W-Gad MRI scans. Our aim was to evaluate SimU-Net, a novel deep-learning model for the detection and volumetric analysis of brain metastases and their temporal changes in paired prior and current scans. METHODS: SimU-Net is a simultaneous multi-channel 3D U-Net model trained on pairs of registered prior and current scans of a patient. We evaluated its performance on 271 pairs of T1W-Gad MRI scans from 226 patients who underwent SRS. An expert oncological neurosurgeon manually delineated 1,889 brain metastases in all the MRI scans (1,368 with diameters > 5 mm, 834 > 10 mm). The SimU-Net model was trained/validated on 205 pairs from 169 patients (1,360 metastases) and tested on 66 pairs from 57 patients (529 metastases). The results were then compared to the ground truth delineations. RESULTS: SimU-Net yielded a mean (std) detection precision and recall of 1.00±0.00 and 0.99±0.06 for metastases > 10 mm, 0.90±0.22 and 0.97±0.12 for metastases > 5 mm of, and 0.76±0.27 and 0.94±0.16 for metastases of all sizes. It improves lesion detection precision by 8% for all metastases sizes and by 12.5% for metastases < 10 mm with respect to standalone 3D U-Net. The segmentation Dice scores were 0.90±0.10, 0.89±0.10 and 0.89±0.10 for the above metastases sizes, all above the observer variability of 0.80±0.13. CONCLUSION: Automated detection and volumetric quantification of brain metastases following SRS have the potential to enhance the assessment of treatment response and alleviate the clinician workload.

Superficial Temporal Artery-Middle Cerebral Artery Microvascular Bypass: Its Role in Treatment of Patients with Moyamoya Disease, Cerebral Aneurysms, and Vascular Occlusive Disease.

BACKGROUND: Superficial temporal artery-middle cerebral artery microvascular bypass (STA-MCA MVB) is an important strategy for the management of selected patients OBJECTIVES: To present our 19-year experience with STA-MCA MVB METHODS: Data for consecutive patients who underwent STA-MCA MVB from 2000­2019 due to moyamoya/moyamoya-like disease, complex intracranial aneurysms, or intractable brain ischemia due to internal carotid artery or MCA occlusive disease with repeated ischemic events were retrospectively analyzed under a waiver of informed consent. Key surgical steps and the important role of neuroendovascular interventions are presented. Surgical results and late outcomes were analyzed RESULTS: The study included 32 patients (17 women [53%], 15 men [47%]), mean age 42.94 years (range 16­66). The patients underwent 37 STA-MCA MVB procedures during the study period: 22 with moyamoya/moyamoya-like disease (69%) underwent 27 surgeries (five bilateral); 7 patients with complex aneurysms (22%) and 3 patients with vascular occlusive disease (9%) underwent unilateral bypass. Five of seven aneurysms were treated with coiling or flow-diverter stent implant prior to bypass surgery; two were clipped during the bypass procedure. There were no surgical complications, no perioperative mortality, and no death from complications related to neurovascular disease at late follow-up. Transient neurological deficits following 7/37 surgeries (19%) resolved with no permanent neurologic sequelae. Transient ischemic attacks occurred only in the immediate postoperative period in four patients (11%) CONCLUSIONS: In specific cases, STA-MCA MVB is a feasible and clinically effective procedure. It is important to preserve this technique in the surgical armamentarium

Very delayed CSF leak in patients after craniotomy for resection of skull base tumors.

OBJECTIVE: Cerebrospinal fluid (CSF) leak is a potentially dangerous neurosurgical complication. Delayed CSF leak has already been described after trauma, radiation therapy and endonasal transsphenoidal surgery for Sella turcica pathologies. Still, very few reported cases describe delayed CSF leak after craniotomy for tumors. We present our experience with patients showing delayed CSF leak after skull base tumor resection. METHODS: Data for all tumors resected from the skull base region from January 2004 to December 2018 was retrieved from the surgeon's prospective database and supplemented with a retrospective file review. Patients who presented CSF leak within the first 12 months after surgery and those with a history of trauma or radiation-based treatment to the skull base region were excluded from the study. Epidemiology, clinical presentation, previous surgical approach, pathology, interval between craniotomy and CSF leak and proposed treatment were analyzed. RESULTS: Overall, more than two thousand patients underwent surgery for resection of skull base tumors during the study period. Six patients (two male, four female; mean age 57.5 years, range 30-80) presented with delayed CSF leak, including five (83%) who presented with bacterial meningitis. After skull base tumor resection, CSF leak developed in a mean of 72 months (range 12-132). Three patients underwent retrosigmoid craniotomy, two for resection of cerebellopontine angle epidermoid cyst and one for resection of a petro tentorial meningioma; one had trans petrosal retrolabyrinthine craniotomy for resection of a petroclival epidermoid cyst; one had far lateral craniotomy for resection of a foramen magnum meningioma; and one had pterional craniotomy for resection of a cavernous sinus meningioma. All patients underwent surgical re-exploration and repair. CSF leak was managed with mastoid obliteration in five patients and skull base reconstruction with fat graft in one. CONCLUSION: Recognition of very delayed CSF leak as a potential complication after resection of skull base tumors may be useful tool in long-term patient management. In our experience, these patients usually present with bacterial meningitis. Surgical options should be considered as a definitive treatment.

Cerebellar liponeurocytoma with an unusual metastatic CSF spinal seeding.

BACKGROUND: Cerebellar liponeurocytoma is rare intracranial tumor appearing mostly in the posterior fossa. CASE DESCRIPTION: We hereby report a long follow-up of a case of cerebellar liponeurocytoma in a 60-year-old female. At first, she presented in March of 2010 with the symptoms of hydrocephalus and was found to have a lesion located in the fourth ventricle. The tumor was resected with a small remnant around the brainstem which grew on serial imaging. Due to slow tumor growth, the patient was treated with conformal radiotherapy and was kept under follow-up with both outpatient visits and serial brain imaging. In 2018, due to low back pain and lumbar radicular pain, a new set of images of the spine was obtained which revealed multilevel intradural tumor spinal dissemination. The patient further underwent an open spinal biopsy at the level of L5 which revealed the same pathology of the intracranial tumor. The patient went on to receive total spine irradiation. CONCLUSION: This case report describes a rare metastatic phenomenon to the spinal cord of the exact same pathology and grade of an intracranial cerebellar liponeurocytoma tumor.