Accuracy and Reproducibility of Linear and Angular Measurements in Virtual Reality: a Validation Study.

The purpose of this experimental study is to validate linear and angular measurements acquired in a virtual reality (VR) environment via a comparison with the physical measurements. The hypotheses tested are as follows: VR linear and angular measurements (1) are equivalent to the corresponding physical measurements and (2) achieve a high degree of reproducibility. Both virtual and physical measurements were performed by two raters in four different sessions. A total of 40 linear and 15 angular measurements were acquired from three physical objects (an L-block, a hand model, and a dry skull) via the use of fiducial markers on selected locations. After both intra- and inter-rater reliability were evaluated using inter-class coefficient (ICC), equivalence between virtual and physical measurements was analyzed via paired t test and Bland-Altman plots. The accuracy of the virtual measurements was further estimated using two one-sided tests (TOST) procedure. The reproducibility of virtual measurements was evaluated via ICC as well as the repeatability coefficient. Virtual reality measurements were equivalent to physical measurements as evidenced by a paired t test with p values of 0.413 for linear and 0.533 for angular measurements and Bland-Altman plots in all three objects. The accuracy of virtual measurements was estimated to be 0.5 mm for linear and 0.7° for angular measurements, respectively. Reproducibility in VR measurements was high as evidenced by ICC of 1.00 for linear and 0.99 for angular measurements, respectively. Both linear and angular measurements in the VR environment are equivalent to the physical measurements with high accuracy and reproducibility.

Renal cell carcinoma presenting as epistaxis from a nasal cavity metastasis.

We present a 58-year-old gentleman who initially presented to the otolaryngology clinic with new onset epistaxis revealing a palpable facial mass that was subsequently biopsied revealing metastatic renal cell carcinoma. We hope to present an interesting case highlighting the rarity of this disease and unusual presentation in which the presence of the primary renal cell carcinoma was recognized only after biopsy.

Primary Orbital Histiocytic Sarcoma in a Child Successfully Treated With Multiagent Chemotherapy.

Histiocytic sarcoma (HS), a malignant proliferation of mature tissue histiocytes presenting with single or multifocal extranodal tumors, is rarely seen in children. Primary orbital HS has never been reported in a child. Disseminated disease to the bone marrow typically has an aggressive course and poor prognosis. There is no consensus currently on the optimal therapeutic approach for HS. We present the case of a 2-year-old girl with orbital HS with likely bone marrow involvement treated successfully with multiagent chemotherapy, now in complete remission and disease free 3.5 years from end of therapy.

Delayed response and survival from NovoTTF-100A in recurrent GBM.

We present a 48-year-old male with recurrent glioblastoma (GBM) who was enrolled in the NovoTTF-100A landmark phase III study and has been on device for >6 years. During this time, his magnetic resonance images demonstrated initial growth followed by a slow decrease in enhancement with continued residual disease. Long-term survivors in patients with recurrent GBM are rare, especially in the absence of definitive local treatment such as surgery or radiosurgery. We present the clinical, imaging and pathological findings for this patient in relation to use of the NovoTTF-100A device.

Unusual CNS presentation of thyroid cancer.

As advanced therapies allow cancer patients to live longer, disease failure in the central nervous system increases from limited therapeutic penetration. Primary thyroid malignancies rarely metastasize to the brain and have a small number of investigations in literature on the subject. The majority of brain metastases involve the brain parenchyma, reflecting the mass and blood distribution within the brain and central nervous system. Here, we report two cases of the most common differentiated thyroid cancers; follicular thyroid cancer having brain involvement from extra-axial growth and papillary thyroid cancer having brain involvement from a single intraventricular metastasis, presumed as metastasis from the vascular choroid plexus. Both of our cases had widespread systemic involvement. For our follicular thyroid cancer, brain involvement was a result of extra-axial growth from cavarial bone, and our papillary thyroid cancer had brain involvement from a single intraventricular metastasis that was initially resected and nearly a year later developed extensive brain involvement. Unlike the usual gray-white junction metastases seen in the majority of metastatic brain tumors, including thyroid, our cases are uncommon. They reflect differences in tumor biology that allows for spread and growth in the brain. Although there is growing genetic knowledge on tumors that favor brain metastases, little is known about tumors that rarely involve the brain.

Prolonged activity of bevacizumab in adenocarcinoma of the lung with multiple brain metastases.

Patients with lung cancer having multiple brain metastases have poor outcomes. We present long-term disease treatment in a 60-year-old woman having greater than thirty brain metastases of NSCLC adenocarcinoma with a mutant allele of EGFR treated with differing chemotherapies including erlotinib, but disease response in the brain only with bevacizumab. Although initially restricted in use, increasing clinical reports have demonstrated safety of bevacizumab use in brain-involved cancer patients. Our case highlights that disease response to bevacizumab is similar in the brain to systemic disease and likely overcomes anatomical barriers that can limit other therapeutic agents.

De novo malignant optic chiasm glioma with initial clinical response to steroids.

Malignant optic nerve glioma (MONG) is a rare but uniformly fatal disease that remains poorly understood. We describe a notable case of this rare disease occurring in the optic chiasm. Normal brain imaging and normal ophthalmic examination two years prior to diagnosis provide evidence for de novo genesis of MONG in our patient. Early response to steroids highlights the degree to which MONG can initially mimic inflammatory optic neuropathies and chiasmal syndromes. Our case also demonstrates a poor outcome with MONG even with current advanced therapy for glioblastoma including radiotherapy plus concomitant and adjuvant temozolomide (the EORTC/NCIC regimen) and bevacizumab.

MRI of orbital cellulitis and orbital abscess: the role of diffusion-weighted imaging.

OBJECTIVE: Our aims were to describe the role of diffusion-weighted imaging (DWI) in detecting abscess as a complication of orbital cellulitis and to assess whether abscess can be diagnosed with a combination of conventional unenhanced sequences and whole-brain DWI with parallel acquisition. Nine cases of orbital cellulitis imaged with MRI were retrospectively reviewed, including six cases with pyogenic abscess. CONCLUSION: In this preliminary study, DWI improved diagnostic confidence in nearly all cases of orbital abscess when used in conjunction with contrast-enhanced imaging. DWI also confirmed abscess in a majority of cases without contrast-enhanced imaging, which may be of particular use when contrast material is contraindicated.

Synchronous moyamoya syndrome and ruptured cerebral aneurysm in Alagille syndrome.

Moyamoya syndrome and cerebral aneurysm formation are rare cerebrovascular manifestations of Alagille syndrome. Although previously reported in isolation, occurrence of these complications in a single patient has not been described. We report clinical and imaging features of synchronous moyamoya syndrome and ruptured cerebral aneurysm in a patient with Alagille syndrome.

Astroblastoma presenting with intracerebral hemorrhage misdiagnosed as dural arteriovenous fistula: review of a rare entity.

BACKGROUND: Astroblastoma is one of the most unusual types of tumors whose histogenesis has been recently clarified. It occurs mainly among children and young adults. It is grossly well demarcated and shows histologically characteristic perivascular pseudorosettes with frequent vascular hyalinization. Immunohistochemically, the tumor cells show diffuse strong positivity for GFAP, S-100 protein, vimentin, as well as neuron-specific enolase and focal positivity for EMA. CASE DESCRIPTION: Our patient is a 33-year-old gentleman who presented with intraparenchymal hemorrhage in the left temporal lobe. A 4-vessel cerebral angiogram revealed a dural AVF in the left posterior temporal area. The lesion was resected, and pathology showed a GFAP-positive lesion with prominent astroblastoma rosettes. There was abundant hemosiderin consistent with a prior hemorrhage. Because of its high degree of proliferation, the presence of astroblastic pseudorosettes, prominent perivascular hyalinization, regional hyaline changes, and pushing borders with regard to the adjacent brain, the tumor was considered anaplastic. CONCLUSIONS: Astroblastoma is a rare pure pathologic entity--a distinct form of astrocytic gliomas. The diagnosis of astroblastoma is often difficult because of the astroblastic aspects that can be found in astrocytic tumors, in ependymomas, and in nonneuroepithelial tumors. The natural history seems to be between astrocytomas and glioblastomas. Total resection and radiation therapy seem to be the advisable treatments.