Imaging of Skull Base and Orbital Invasion in Sinonasal Cancer: Correlation with Histopathology

Background: Pretreatment assessment of local extension in sinonasal cancer is essential for prognostic evaluation and surgical planning. The aim of this study was to assess the diagnostic performance of two common imaging techniques (CT and MRI) for the diagnosis of skull base and orbital invasion by comparing imaging findings to histopathological data. Methods: This was a retrospective two-center study including patients with sinonasal cancer involving the skull base and/or the orbit operated on between 2000 and 2019. Patients were included only if pre-operative CT and/or MRI, operative and histopathologic reports were available. A double prospective blinded imaging review was conducted according to predefined radiological parameters. Radiologic tumor extension was compared to histopathological reports, which were considered the gold standard. The predictive positive value (PPV) for the diagnosis of skull base/orbital invasion was calculated for each parameter. Results: A total of 176 patients were included. Ethmoidal intestinal-type adenocarcinoma was the most common type of cancer (41%). The PPV for major modification of the bony skull base was 78% on the CT scan, and 89% on MRI. MRI signs of dural invasion with the highest PPVs were: contact angle over 45° between tumor and dura (86%), irregular deformation of dura adjacent to tumor (87%) and nodular dural enhancement over 2 mm in thickness (87%). Signs of orbital invasion had low PPVs (<50%). Conclusions: This retrospective study provides objective data about the diagnostic value of pretreatment imaging in patients with sinonasal cancer.

Isolated Myelitis and Intramedullary Spinal Cord Abscess in Melioidosis—A Case Report

Neuromelioidosis is a severe tropical infection with high morbidity and mortality. Isolated myelitis is an extremely rare manifestation of melioidosis which may evade diagnosis. We report a 69-year-old diabetic male patient who presented with acute flaccid paraplegia and longitudinally extensive myelitis and no systemic symptoms. MRI of spinal cord showed lower dorsal cord and conus T2 hyperintensity and microabscesses with dural enhancement. The diagnosis was clinched with blood culture growing Burkholderia pseudomallei. He rapidly developed colitis, septicemia and multiorgan dysfunction and succumbed to the illness in spite of antibiotics and aggressive supportive care. The case highlights that melioidosis should be considered as a differential diagnosis of infectious myelitis, especially in the tropics. Presence of a neutrophilic blood and cerebrospinal fluid picture and microabscesses in spinal cord are important diagnostic clues. The outcome is dismal unless the diagnosis is considered early in the disease course and managed expeditiously with sensitive antibiotics.

Dural venous system: angiographic technique and correlation with ex vivo investigations

BackgroundThe dural vasculature plays a key role in several important conditions, including dural fistulas and subdural collections. While in vivo investigations of intrinsic dural arterial angioarchitecture are rare, no angiographic studies of dural venous drainage exist to our knowledge.ObjectiveTo describe methods by which dural venous drainage might be visualized with current angiographic equipment and technique, and to correlate our results with existing ex vivo literature.MethodsDigital subtraction angiography and 3D angiography (rotational and Dyna CT) of dural neurovasculature were acquired in the context of subdural hematoma embolization and normal dura. Protocols for visualization of dural venous drainage were established, and findings correlated with ex vivo studies.ResultsMeningeal arteries supply both the skull and dura. Normal dural enhancement is accentuated by the presence of hypervascular membranes. Intrinsic meningeal veins/sinuses parallel outer layer arteries with well-known tram-tracking appearance. Dura adjacent to main arterial trunks drains via skull base foramina into the pterygopalatine venous plexus, or via emissary veins into the temporalis venous plexus. Dura near the sinuses drains into venous pouches adjacent to the sinus, before emptying into the sinus proper—possibly the same pouches implicated in the angioarchitecture of dural fistulas. Finally, posterior temporoparietal convexity dura, situated in a watershed-like region between middle and posterior meningeal territories, frequently empties into diploic and emissary veins of the skull. Wide variation in balance is expected between these three routes. Drainage patterns appear to correlate with venous embryologic investigations of Padget and ex vivo studies in adults.ConclusionsContinued attention to dural venous drainage may prove useful in the diagnosis and management of dural-based vascular diseases.

Parinaud syndrome as an unusual presentation of intracranial hypotension

Background: Vertical gaze palsy is a rare clinical manifestation of intracranial hypotension. The typical features of intracranial hypotension include a postural headache, dural enhancement, and low cerebrospinal fluid (CSF) opening pressure. Case Description: We describe a case of a shunt-dependent middle-aged female with aqueductal stenosis who developed recurrent presentations of upgaze palsy with postural headaches, confirmed low opening pressure, and slit ventricles on magnetic resonance imaging (MRI) due to shunt overdrainage. Her ophthalmoplegia and headaches improved following third ventriculostomy and with increasing the shunt opening pressure to prevent excess CSF drainage. Conclusion: Intracranial hypotension should be considered part of the differential diagnosis for patients presenting with an upgaze palsy.

1520. Streptococcus anginosus Group Organisms Are an Increasing Cause of Complicated Sinusitis and Otitis Media in Children

Background The Streptococcus anginosus group (SAG), including S. anginosus, S. intermedius and S. constellatus, are common flora of the oral cavity, respiratory tree and gastrointestinal tract. However, these organisms have the potential to cause serious invasive infections and are notably pyogenic. We observed an apparent increase in the frequency of intraorbital and intracranial infections resulting from SAG at Texas Children’s Hospital (TCH). We undertook a retrospective review to describe the frequency and clinical features of these infections. Methods We reviewed the database of the clinical microbiology laboratory at TCH from 2011 to 2018 for SAG-positive cultures. For purposes of this study, cases included were those associated with 1) either otitis media or sinusitis and 2) Pott’s Puffy Tumor, orbital abscesses, epidural abscesses, subdural empyema, brain parenchymal abscesses, dural enhancement by imaging or mastoiditis. Similar methods were used for SAG identification throughout the study period. The number of cases per year was used along with annual hospital admissions data to estimate case rate; case rate trends were examined using linear regression. Results 950 cultures positive for SAG were identified by the clinical lab; 95 cases met inclusion criteria. The median age of patients was 11.4 years. Specific diagnoses are presented in Figure 1. S. intermedius was most commonly isolated (81.1%) followed by S. constellatus (12.6%) and S. anginosus (7.4%); 50.5% of cases were polymicrobial. Among polymicrobial cases, S. aureus was most frequently isolated (25%). All patients underwent surgical intervention and 20.5% underwent ≥2 procedures (Figure 2). 16.8% were associated with intracranial thromboses and 4.2% with CNS infarcts; 8.4% of patients experienced persistent neurologic deficits. All isolates were susceptible to penicillin. We observed an increase in the annual disease rate during the study (Figure 3, P = 0.01). Conclusion Complications of otitis media and sinusitis due to SAG are associated with substantial morbidity. These infections are becomingly increasingly common at our center although the precise reason for this temporal trend is unclear. Multicenter studies are needed to validate these epidemiologic findings. Disclosures All authors: No reported disclosures.

RADI-12. LEPTOMENINGEAL FAILURE AFTER PREOPERATIVE VERSUS POSTOPERATIVE RADIOSURGERY

INTRODUCTION: Postoperative stereotactic radiosurgery (postop SRS) is potentially complicated by difficulty defining the target volume and the risk of leptomeningeal seeding at the time of surgery. It is hypothesized that preop SRS may render cells less viable to disseminate in the leptomeningeal space. This retrospective study compares the leptomeningeal dissemination (LMD) rate for preop versus postop radiosurgery METHODS: We identified 140 patients with brain metastases who underwent resection and radiosurgery at the University of Alabama at Birmingham including 91 postop patients (2005–2015) and 49 preop patients (2011–2018). The preop group included 19 patients enrolled in a phase I trial of preoperative radiosurgery (12–15 Gy) for tumors 2–6 cm in greatest diameter. In that study 15 Gy was found to be safe in the preop setting but further escalation was not attempted. An additional 30 patients received preop SRS off-study (median dose 15 Gy). The median postop dose was 16 Gy. LMD recurrence was defined as focal pachymeningeal or diffuse leptomeningeal enhancement of the brain, spinal cord, or cauda equina, dural enhancement beyond 5 mm from the index metastasis, subependymal enhancement, or enhancement of cranial nerves. This definition is not limited to carcinomatosis. All events were categorized and confirmed by at least two physicians. RESULTS: 40/140 (29%) patients developed new focal or diffuse LMD. Preop SRS was associated with a higher freedom from leptomeningeal recurrence (84% vs 60% at one year, p=0.021 Breslow, p=0.128 log-rank). Since later LMD may not be related to surgery, a second analysis censoring follow-up at one year was performed and confirmed this trend (p=0.008 Breslow, p=0.014 log-rank). CONCLUSIONS: Preoperative SRS is associated with a reduction in the risk of LMD compared to postop SRS. Focal pachymeningeal dissemination may not always be recognized as related to surgery. A randomized trial of preop vs postop SRS is warranted.

Diagnostic performance of CT, MRI, and their combined use for the assessment of the direct cranial or intracranial extension of malignant head and neck tumors

Background Preoperative radiological evaluation of the cranial or intracranial extension of malignant head and neck tumors is critical in the planning of curative surgery. Purpose To assess the diagnostic accuracy of computed tomography (CT) combined with magnetic resonance imaging (MRI), compared to CT or MRI alone in diagnosing the direct cranial or intracranial extension of malignant head and neck tumors, using histopathologic results as the reference standard. Material and Methods CT and MRI images in 41 patients with malignant head and neck tumors abutting the skull were retrospectively reviewed. The images were evaluated for the presence or absence of skull invasion (erosion/destruction of the skull), dural invasion (nodular dural enhancement), and brain invasion (enhancing brain lesion with or without brain swelling/edema). The results of the CT alone, MRI alone, and CT combined with MRI were compared with the histopathologic findings. Results Of the 41 patients studied, ten had no invasion, eight had skull invasion, 17 had dural invasion, and six had brain invasion by tumor. The sensitivity/specificity/accuracy of CT alone, MRI alone, and CT combined with MRI for diagnosing intracranial extension were 78.0%/100%/94.5%, 85.4%/80.5%/93.9%, and 95.1%/100%/98.8%, respectively. The sensitivity of CT combined with MRI was significantly higher than those of CT alone ( P = 0.0156) and MRI alone ( P = 0.0313). Conclusion CT combined with MRI is a more sensitive tool for the diagnosis of the direct cranial or intracranial extension of malignant head and neck tumors than CT alone and MRI alone.

Internal Auditory Canal Dural Enhancement in Granulomatosis with Polyangeitis Disease

Diffuse dural enhancement of the internal auditory canal in T1-weighted gadolinium-enhanced magnetic resonance imaging could be a helpful and early clinical sign in a very aggressive limited granulomatosis with polyangeitis disease, called previously Wegener Disease (WD).