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Introduction High-resolution computed tomography (HRCT) scans of the temporal bone are used to assess the bony erosion of the middle-ear structures whenever cholesteatoma is suspected. Objective To study the differences in HRCT Hounsfield unit (HU) index measurements of middle-ear bony structures between an ears with and without cholesteatoma. Methods A retrospective study of 59 patients who underwent surgery due to unilateral cholesteatoma. The HRCT HU index of the scutum, of three middle-ear ossicles, of the lateral semicircular canal (LSCC), and of the fallopian canal was measured in both ears. A comparison was made between the cholesteatoma and the non-cholesteatomatous ear (control). All measurements were conducted by an otolaryngologist. To assess the interobserver bias, 10% of the samples were randomly and independently assessed by another otolaryngologist and a neuroradiologist who were blinded. Results The average HU index was lower in the ear with cholesteatoma when compared with the non-cholesteatomatous ear. While the differences were statistically significant regarding the measurements of the scutum (516.02 ± 311.693 versus 855.64 ± 389.999; p = 0.001), the malleus (1049.44 ± 481.765 versus 1413.47 ± 313.376; p = 0.01), and the incus (498.03 ± 264.184 versus 714.25 ± 405.631; p = 0.001), the differences in the measurements of the LSCC (1042.34 ± 301.066 versus 1154.53 ± 359.609; p = 0.69) and of the fallopian canal (467.19 ± 221.556 versus 543.51 ± 263.573; p = 0.108) were not significantly different between both groups. The stapes was immeasurable in both groups due to its small size. Conclusion Hounsfield unit index measurements are a useful tool that may aid in the diagnosis of early-stage cholesteatoma.

Background Erdheim–Chester disease (ECD), a rare inflammatory myeloid neoplasm, is known to be fundamentally reliant on the constitutive activation of the MAPK signaling pathway in the majority of patients. Consequently, inhibition of the V600E-mutant BRAF kinase has proven to be a safe and efficacious long-term therapeutic strategy for BRAF-mutant ECD patients. Nevertheless, in a subset of patients with CNS disease, the efficacy of long-term treatment may diminish, facilitating suboptimal responses or disease progression. Methods We retrospectively describe 3 BRAF-mutant ECD patients whose treatment with Vemurafenib was upgraded to Vemurafenib/Cobimetinib due to either disease progression, insufficient response, or unacceptable toxicity. CNS response to therapy was evaluated using magnetic resonance imaging (MRI) and extra-cranial disease was monitored using 18F-fludeoxyglucose positron emission tomography/computed tomography (PET/CT). Results Three patients with a mean age of 52.6 years were treated with Vemurafenib for a mean duration of 26.6 months (range: 6–52). Monotherapies were upgraded to Vemurafenib/Cobimetinib dual therapy. The combination therapy was administered for a mean duration of 21 months (range: 19–23). All patients exhibited clinical and neurological improvement. Regression of lesions on MRI was noted in 2 patients. Both patients characterized by a PET-avid disease responded to the biological treatment regimen with complete metabolic remissions. Conclusion Dual inhibition of BRAF and downstream MEK may be a safe and effective therapeutic strategy for BRAF-mutant ECD patients for whom BRAF inhibitor therapy proved insufficient and as such appropriate for the long-term management of CNS disease in ECD.

BACKGROUND The need for an extensive evaluation for neuroblastoma in children with Horner syndrome is controversial. METHODS A retrospective study design was used. The cohort included 47 children with anisocoria who were diagnosed with Horner syndrome and 135 children with neuroblastoma evaluated at a pediatric medical center between 2007 and 2015. To detect neuroblastoma, patients with Horner syndrome underwent brain and cervical MRI, abdominal ultrasound, and/or measurement of urinary vanillylmandelic acid (VMA). The neuroblastoma group was evaluated for signs/symptoms of Horner syndrome at the time of diagnosis. RESULTS Seven patients with Horner syndrome were lost to follow-up, and the findings of the remaining 40 were categorized according to the age of the patient. Horner syndrome most frequently was idiopathic (58%), and in only 1 patient did the discovery of neuroblastoma precede the appearance of Horner syndrome. In the 21 patients aged 1-18 years, Horner syndrome was acquired in 15 patients and congenital in 6. The most common etiology was trauma (62%). Imaging was performed in 14 patients and VMA testing in 13. Neuroblastoma was diagnosed in 5 patients; in none was it related to Horner syndrome. In the 135 patients with neuroblastoma, most of the tumors were diagnosed at Stage 4 (60%) or Stage 3 (30%) with 53% originating in the abdomen. In one patient (0.74%) with signs/symptoms of Horner syndrome at diagnosis of neuroblastoma, the tumor had been identified prenatally and the diagnosis confirmed by imaging postnatally. CONCLUSIONS The absence of occult neuroblastoma in children with Horner syndrome and of signs/symptoms of Horner syndrome in the children diagnosed with neuroblastoma suggests that Horner syndrome might not be as frequent a cause of neuroblastoma as previously thought. We recommend that full investigation for neuroblastoma be reserved for suspicious cases associated with additional systemic signs or symptoms.

INTRODUCTION: Gadolinium-based contrast agents (GBCAs) are routinely used in MRI studies performed for evaluation of brain tumors. Recent studies have demonstrated, progressively increased signal intensity in the globus pallidus (GP) and dentate nucleus (DN) on T1-weighted brain images obtained in patients undergoing repeated MR studies. Linear GBCAs result in more retention and longer time of retention than macrocyclic GBCAs. The aim of this study is to evaluate changes in signal intensity ratios of the GP and the DN on unenhanced T1-weighted images after multiple administrations of macrocyclic GBCAs in brain tumor patients. METHODS: The study included 37 patients with primary brain tumors who had more than 3 MRI evaluations (range: 4–10 studies). Ten of them (27%) have not receive radiation therapy. Patients were divided into two groups: Group 1 included 24 patients who had Gadoterate meglumine (Dotarem®) enhanced MRI and group 2 included 13 patients who had Gadobutrol (Gadavist®) enhanced MRI. Median age of group 1 patients was 46 (24–69) years and of group 2 it was 56 (32–67). Two radiologists conducted a quantitative analysis of unenhanced T1-weighted images by using region of interest measurements. The difference in mean GP-to-thalamus (GP\TH) signal intensity ratio, DN-to-middle cerebellar peduncle (DN\MCP) signal intensity ratio between the first and last examinations for each patient were calculated. RESULTS: In both groups GP \TH Ratio difference was greater than 0 (Gadavist 0.08 ± 0.06, Dotarem 0.02 ± 0.08 [P=0.035]) following multiple MRI examinations. There was no significant change in DN\MCP ratio in both groups (Gadavist 0.02 ± 0.07, Dotarem -0.01 ± 0.08 [P=0.230]). CONCLUSION: A significant increased GP\Thal ratio is associated with multiple administrations of both macrocyclic agents, but to a greater extent with administration of Gadavist possibly reflecting the difference in elimination and stability of both contrast agents. Further studies are needed to identify clinical implications, if any, of these findings.

INTRODUCTION: Gadolinium-based contrast agents (GBCAs) are routinely used in MRI studies performed for evaluation of brain tumors. Recent studies have demonstrated, progressively increased signal intensity in the globus pallidus (GP) and dentate nucleus (DN) on T1-weighted brain images obtained in patients undergoing repeated MR studies. Linear GBCAs result in more retention and longer time of retention than macrocyclic GBCAs. The aim of this study is to evaluate changes in signal intensity ratios of the GP and the DN on unenhanced T1-weighted images after multiple administrations of macrocyclic GBCAs in brain tumor patients. METHODS: The study included 37 patients with primary brain tumors who had more than 3 MRI evaluations (range: 4–10 studies). Ten of them (27%) have not receive radiation therapy. Patients were divided into two groups: Group 1 included 24 patients who had Gadoterate meglumine (Dotarem®) enhanced MRI and group 2 included 13 patients who had Gadobutrol (Gadavist®) enhanced MRI. Median age of group 1 patients was 46 (24–69) years and of group 2 it was 56 (32–67). Two radiologists conducted a quantitative analysis of unenhanced T1-weighted images by using region of interest measurements. The difference in mean GP-to-thalamus (GP\TH) signal intensity ratio, DN-to-middle cerebellar peduncle (DN\MCP) signal intensity ratio between the first and last examinations for each patient were calculated. RESULTS: In both groups GP \TH Ratio difference was greater than 0 (Gadavist 0.08 ± 0.06, Dotarem 0.02 ± 0.08 [P=0.035]) following multiple MRI examinations. There was no significant change in DN\MCP ratio in both groups (Gadavist 0.02 ± 0.07, Dotarem -0.01 ± 0.08 [P=0.230]). CONCLUSION: A significant increased GP\Thal ratio is associated with multiple administrations of both macrocyclic agents, but to a greater extent with administration of Gadavist possibly reflecting the difference in elimination and stability of both contrast agents. Further studies are needed to identify clinical implications, if any, of these findings.

Parainfectious optic neuritis may appear at any age. The aim of our report was to compare the clinical manifestations and outcomes of this form of optic neuritis between children and adults.The study sample consisted of all patients diagnosed with parainfectious optic neuritis evaluated by 2 neuro-ophthalmology services between 2005 and 2012. Data were collected retrospectively from the medical files. Findings were compared between patients aged 0-18 years and 19 years or older.Ten children (50% female) and 8 adults (50% female) met the study criteria. Mean duration of follow-up was 29.4 months (range, 2-72 months) in the pediatric group and 14.2 months (range, 5-80 months) in the adult group. Respective rates of bilateral disease were 50% and 38%, and all patients had optic disc swelling. The associated pathogen was identified in 60% of the pediatric group, mainly Mycoplasma pneumoniae, and 75% of the adult group, in which no microorganism predominated. The interval from the febrile illness to symptom onset was 6 days (range, 1-14 days) in the pediatric group and 19.5 days (range, 14-30 days) in the adult group. Acute disseminated encephalomyelitis (ADEM) was diagnosed in 40% (4/10) of the children and none of the adults. Final visual outcome was 20/30 or better in all patients. There was a higher frequency of bilateral disease in prepubescent vs postpubescent children.Parainfectious optic neuritis is associated with a favorable visual prognosis regardless of age. Children tend to manifest visual symptoms sooner after the antecedent infectious illness and more often bilaterally and in conjunction with ADEM. The causative agent is isolated less frequently in children compared with adults.

High grade astrocytomas and glioblastoma are the most aggressive and frequent type of primary central nervous system tumor [1]. In adults, 70% of tumors are located supratentorially, while tumors of the brainstem and cerebellum are less common. Spinal cord astrocytic tumors, of all grades, are relatively rare [2] and comprise about 35% of all intramedullary tumors [3]. The minority of these tumors are high grade astrocytomas that constitute about 3% of all intramedullary tumors [3]. The presence of synchronous non-congruent cerebral and spinal cord lesions is extremely uncommon, and the disparity of imaging characteristics of the lesions is even more misleading. The use of positron emission tomography (PET)-CT scanning in the evaluation of these lesions pointed toward a diagnosis of primary central nervous system tumors and indicated that the spinal area had a highly active metabolic level indicative of a malignant etiology. Considering the differential diagnosis in this patient the fludeoxyglucose (FDG) PET scan (Fig. 1) proved valuable as a diagnostic clue and as an indicator of the biopsy site that would most likely render an informative tissue sample. This kind of targeting is highly important in lesions like those found in our patient where tissue diagnosis is particularly risky [4–7]. The disparity in the imaging characteristics of the brainstem and spinal cord tumors as well as the fact that only the spinal lesion showed high FDG uptake indicates that the tumor grade may differ in the two lesions and that the brainstem tumor may be of a lower grade. Yet, following treatment with concurrent radiotherapy and temozolomide the brainstem lesion showed clear response on the first follow-up imaging still suggestive of a high grade glioma.

Background To compare preoperative CT/MRI based predictions with real surgical findings for deep lobe parotid gland surgery. Methods The study analyzed 122 parotidectomies (2004–2014) for benign tumor removal. The facial nerve, the Utrecht line, the Conn’s arc, and the retromandibular vein were used as landmarks for CT/MRI presurgical evaluation of patients. We assessed 106 CT images and 86 MRI images. The study compared preoperative evaluation of tumor location with its actual location that was revealed during the operation and assessed the importance of the landmarks. Results In general, the agreement between preoperative CT prediction and actual location of the parotid tumors was achieved in 88.7 % (n = 94/106) when facial nerve line was used as a landmark. However, out of 14 tumors in the deep lobe only 5 were located correctly (35.7 %). Of the other existing CT landmarks, none showed more precision over others. The agreement between MRI based prediction and surgical results on actual location of the tumor was achieved in 94.2 %. Out of 12 MRI-investigated tumors in the deep lobe nine were located correctly that gives 75 % agreement with surgical results. Conclusion Our data suggests that no existing CT landmark can be accepted as completely reliable in cases when selective deep lobe parotidectomy is planned. If tumor location is suspected in the deep lobe of the gland, MRI imaging is necessary to confirm the diagnosis. An operating surgeon should be prepared that in some cases the true location of the tumor would be revealed only during surgery.