Comparison of ABR and ASSR using narrow-band-chirp-stimuli in children with cochlear malformation and/or cochlear nerve hypoplasia suffering from severe/profound hearing loss.

OBJECTIVES: In pediatric audiology, objective techniques for hearing threshold estimation in infants and children with profound or severe hearing loss play a key role. Auditory brainstem responses (ABR) and auditory steady-state responses (ASSR) are available for frequency-dependent hearing threshold estimations and both techniques show strong correlations but sometimes with considerable differences. The aim of the study was to compare hearing threshold estimations in children with and without cochlear and cochlear nerve malformations. METHODS: Two groups with profound or severe hearing loss were retrospectively compared. In 20 ears (15 children) with malformation of the inner ear and/or cochlear nerve hypoplasia and a control group of 20 ears (11 children) without malformation, ABR were measured with the Interacoustics Eclipse EP25 ABR system® (Denmark) with narrow-band CE-chirps® at 500, 1000, 2000 and 4000 Hz and compared to ASSR at the same center frequencies under similar conditions. RESULTS: ABR and ASSR correlated significantly in both groups (r = 0.413 in malformation group, r = 0.82 in control group). The malformation group showed a significantly lower percentage of "equal" hearing threshold estimations than the control group. In detail, patients with isolated cochlear malformation did not differ significantly from the control group, whereas patients with cochlear nerve hypoplasia showed significantly greater differences. CONCLUSION: ABR and ASSR should be used jointly in the diagnostic approach in children with suspected profound or severe hearing loss. A great difference in hearing threshold estimation between these techniques could hint at the involvement of cochlear nerve or cochlear nerve hypoplasia itself.

The nasal valve: new insights on the static and dynamic NV with MR-imaging.

PURPOSE: We assessed the static nasal valve angle with MR imaging in healthy subjects and evaluated the complex mechanism of nasal valve dynamics during physiologic and forced inspiration. METHODS: In 17 healthy subjects, measurements of the static nasal valve angle were conducted on MR scans, using a TSE Axial T2-weighted sequence and a 3 mm slice thickness. The dynamic changes of nasal valve movement were detected using MR Cine-imaging techniques. RESULTS: The static median angle of the nasal valve was found to be 28.6° with a range of 12.7°-39.3°. The median degree of nasal valve collapse during forced inspiration was 68% (range 20-99%) of the baseline (static nasal valve angle). In the moderately forced inspiration (3 s) the median nasal valve angle declined to 76% of the baseline angle (range 42-100%). In the physiologic or unforced inspiration, the median nasal valve angle was reduced to 86.3% of the baseline angle (range 52-100%). CONCLUSION: MRI, as a non-invasive tool, is a reliable method for evaluation of the static nasal valve angle and for the illustration of the complex nasal valve dynamics.

Correction to: Clinical manifestations of hydropic ear disease (Menière's).

In the original publication, Fig. 1 was incorrectly published with incomplete legends.

Clinical manifestations of hydropic ear disease (Menière's).

INTRODUCTION: Hydropic ear disease, initially described by and named after Prosper Menière, is one of the most frequent vertigo disorders and one of the most frequent inner ear disorders. It is the syndrome of endolymphatic hydrops which until 2007 could be diagnostically confirmed only by post-mortem histology. In the past, various attempts to formulate clinical diagnostic criteria have been undertaken but were hampered by the inability to ascertain the diagnosis in living patients. With the milestone achievement of endolymphatic hydrops imaging, today the pathology can be ascertained. In this study, we have performed a detailed analysis of the clinical features of hydropic ear disease for the first time by examining a large cohort of patients with morphologically confirmed endolymphatic hydrops using a detailed physician-administered neurotologic face-to-face interview. RESULTS: During a hydropic vertigo attack, the patients report nausea, vomiting, sweating, urge to defecate, urge to urinate, phosphenes, headache, photophobia, phonophobia and even transient loss of consciousness. A third of the patients does not experience auditory symptoms during the vertigo attacks. Vertigo attacks last less than 20 min in more than one-fourth of the patients. Audiometric hearing loss has its greatest diagnostic value at the frequencies of 1 kHz and below. Cochleovestibular symptom onset simultaneity is associated with a high frequency of drop-attacks. Migraine and autoimmune disorders are not associated with hydropic ear disease. CONCLUSION: This study marks the beginning of the clinical characterization of hydropic ear disease. The findings have important implications for the future formulation of clinical diagnostic criteria.

Feasibility of low-dose digital pulsed video-fluoroscopic swallow exams (VFSE): effects on radiation dose and image quality.

Background Fluoroscopy is a frequently used examination in clinical routine without appropriate research evaluation latest hardware and software equipment. Purpose To evaluate the feasibility of low-dose pulsed video-fluoroscopic swallowing exams (pVFSE) to reduce dose exposure in patients with swallowing disorders compared to high-resolution radiograph examinations (hrVFSE) serving as standard of reference. Material and Methods A phantom study (Alderson-Rando Phantom, 60 thermoluminescent dosimeters [TLD]) was performed for dose measurements. Acquisition parameters were as follows: (i) pVFSE: 76.7 kV, 57 mA, 0.9 Cu mm, pulse rate/s 30; (ii) hrVFSE: 68.0 kV, 362 mA, 0.2 Cu mm, pictures 30/s. The dose area product (DAP) indicated by the detector system and the radiation dose derived from the TLD measurements were analyzed. In a patient study, image quality was assessed qualitatively (5-point Likert scale, 5 = hrVFSE; two independent readers) and quantitatively (SNR) in 35 patients who subsequently underwent contrast-enhanced pVFSE and hrVFSE. Results Phantom measurements showed a dose reduction per picture of factor 25 for pVFSE versus hrVFSE images (0.0025 mGy versus 0.062 mGy). The DAP (µGym2) was 28.0 versus 810.5 (pVFSE versus hrVFSE) for an average examination time of 30 s. Direct and scattered organ doses were significantly lower for pVFSE as compared to hrVFSE ( P < 0.05). Image quality was rated 3.9 ± 0.5 for pVFSE versus the hrVFSE standard; depiction of the contrast agent 4.8 ± 0.3; noise 3.6 ± 0.5 ( P < 0.05); SNR calculations revealed a relative decreased of 43.9% for pVFSE as compared to hrVFSE. Conclusion Pulsed VFSE is feasible, providing diagnostic image quality at a significant dose reduction as compared to hrVFSE.

Morphometric evaluation of facial and vestibulocochlear nerves using magnetic resonance imaging: comparison of Menière's disease ears with normal hearing ears.

Loss of neural structures (such as hair cells or neurones within the spiral ganglion) has been proposed to be involved in Menière's disease (MD) (Spoendlin et al. Acta oto-laryngologica Supplementum 499:1-21, 1; Merchant et al. Eur Arch Oto-Rhino-Laryngol Off J Eur Feder Oto-Rhino-Laryngol Soc (EUFOS) Affil German Soc Oto-Rhino-Laryngol Head Neck Surg 252(2):63-75, 2; Tsuji et al. Ann Otol Rhinol Laryngol Suppl 81:26-31, 3; Kariya, Otol Neurotol Off Publ Am Otol Soc Am Neurotol Soc Eur Acad Otol Neurotol 28(8):1063-1068, 4; Megerian Laryngoscope 115(9):1525-1535, 5) but this has yet to be confirmed. Therefore, the aim of this study was to investigate morphometric changes of VIIth and VIIIth cranial nerve in MD. MD is characterized by episodic vertigo, tinnitus, fluctuating hearing loss, and aural fullness. The exact pathophysiological mechanisms involved such as viral infections, autoimmune processes, genetic predisposition, cellular apoptosis, and oxidative stress are still not clear. Using a T2-weighted 3D-GE "constructive interference in steady state" (CISS) 3T magnetic resonance imaging (MRI) sequence, we evaluated the properties of the VIIth and VIIIth cranial nerves as they passed from the cerebellopontine angle to the inner ear modiolus. 21 patients with MD were examined along with 39 normal controls. Bidirectional nerve diameters and cross-sectional areas (CSA) were measured in a transverse plane. The comparison of study and control group showed statistically significant (P < 0.000595 after Bonferroni correction) differences between the CSA measurements. The facial, cochlear, superior vestibular, and inferior vestibular nerves (FN, CN, SVN, IVN) of MD patients were significantly larger than those of the control group, both on the MD-affected side and on the healthy side. Thus for example, the cochlear nerve CSA measurements were 0.69 ± 0.14 mm2 (P < 0.0001) in the affected ears of the unilateral MD group, 0.70 ± 0.12 mm2 (P < 0.0001) in the affected ears of the cohort including the bilateral MD group, 0.71 ± 0.13 mm2 (P < 0.0001) in the non-affected ears of the MD patients, as compared to 0.46 ± 0.14 mm2 in the control group. The perpendicular nerve diameters were found to vary according to site of measurement and type of measurement used. For example a statistically significant enlargement of the short diameter measurements of the SVN at the level of the meatus was found, but not of long diameter measurements at the same site. Although cellular death would theoretically be expected to lead to a decreased nerve thickness, our data showed a swelling of cranial nerves VII and VIII within the study group compared to our normal hearing control group. The similar reaction of the facial nerve supports mediator-based theories of MD pathophysiology.

Feasibility of optimized ultralow-dose pulsed fluoroscopy for upper gastrointestinal tract examinations: a phantom study with clinical correlation.

PURPOSE: To establish an optimized ultralow-dose digital pulsed fluoroscopy (FP) protocol for upper gastrointestinal tract examinations and to investigate the radiation dose and image quality. MATERIALS AND METHODS: An Alderson-Rando-Phantom with 60 thermoluminescent dosimeters was used for dose measurements to systematically evaluate the dose-area product (DAP) and organ doses of the optimized FP protocol with the following acquisition parameters: 86.7 kV; 77 mA; 0.9 mm3, automatic image noise and contrast adaption. Subjective image quality, depiction of contrast agent and image noise (5-point Likert scale; 5 = excellent) were assessed in 41 patients, who underwent contrast-enhanced FP with the aforementioned optimized protocol by two radiologists in consensus. A conventional digital radiograph (DR) acquisition protocol served as the reference standard for radiation dose and image quality analyses. RESULTS: Phantom measurements revealed a general dose reduction of approximately 96% per image for the FP protocol as compared to the DR standard. DAP could be reduced by 97%. Significant dose reductions were also found for organ doses, both in the direct and scattered radiation beam with negligible orbital (FP 5.6 × 10-3 vs. DR 0.11; p = 0.02) and gonadal dose exposure (female FP 2.4 × 10-3 vs. DR 0.05; male FP 8 × 10-4 vs. DR 0.03; p ≤ 0.0004). FP provided diagnostic image quality in all patients, although reading scores were significantly lower for all evaluated parameters as compared to the DR standard (p < 0.05). CONCLUSION: Ultralow-dose FP is feasible for clinical routine allowing a significant reduction of direct and scattered dose exposure while providing sufficient diagnostic image quality for reliable diagnosis.

[Head injuries and their wound treatment]. / Verletzungen am Kopf und ihre Wundbehandlung.

Head injuries are frequent occurrences in emergency departments worldwide and are notable for the fact that attention must be paid to the sequelae of intracranial and extracranial trauma. It is crucial to assess potential intracranial injuries and to strive for both medically sound and esthetically pleasing extracranial outcomes. The aim of this continuing education article is to provide a refresher on knowledge of head injuries and the associated nuances for wound care.

Hertel-exophthalmometry-like multi-detector-row-CT-exophthalmometry: inter-disciplinary inter-observer reproducibility of measurements.

OBJECTIVES: To investigate the interdisciplinary interobserver reproducibility of Hertel-exophthalmometry-like protrusion measurements on multidetector-row-computed-tomography- (MDCT-) images of the orbit to facilitate structured evaluation of the orbit and mid-face. METHODS: Respective reproducibility of base-length along the interfronto-zygomatic line, right and left ocular protrusion, and deriving interocular difference was measured in this retrospective (04/2009-03/2020) single-centre observational study. MDCT-series and slice-positions were selected independently, using picture-archiving-and-communication-system- (PACS-) tools on tilt-corrected axial MDCT-images (slice-thickness 0.6-3.0 mm, window/centre 350/50 HU) in 37 selected adult patients (24 female, age 57 ± 13 years, average±standard-deviation) with clinical indication for Hertel-exophthalmometry, by one radiology-attending, two ophthalmology-attendings, one critical-care-attending, and one ear-nose-throat-surgery resident, respectively. Bland-Altman plots and Wilcoxon-matched-pairs-signed-rank-tests compared interobserver results. RESULTS: Mean and median interobserver and intraobserver (radiology-attending) deviations were within 1 mm of respective averages of base-length (98 ± 4 mm), right and left ocular protrusion (21 ± 4 mm) and interocular difference (2 ± 1 mm). Relative interobserver deviations were within 2.0% of average (all patients) for base-length, and 5.0% (>80% of patients) for ocular protrusion. Pairwise interobserver comparison showed no significant differences between interocular differences of protrusion. CONCLUSIONS: Respective measurements of base-length, ocular protrusion, and deriving interocular difference show high interdisciplinary interobserver reproducibility in tilt-corrected axial MDCT-images of the orbit or mid-face. ADVANCES IN KNOWLEDGE: Hertel-exophthalmometry-like protrusion measurements did not depend on the years of experience or the medical subspecialty of the observer. Measurements are objective, well reproducible and important for multiple medical disciplines and should thus be included in pertinent radiology reports.

Short-term audiologic effect of intratympanic gadolinium contrast agent application in patients with Ménière's disease.

OBJECTIVES: The aim of this study was to assess whether gadolinium-based contrast agent influences short-term hearing function in patients with Ménière's disease undergoing intratympanically enhanced inner-ear magnetic resonance imaging. DESIGN: This is a prospective cohort study. SETTING: This study was conducted a tertiary referral university hospital, ENT department. PARTICIPANTS: In this study, 21 adult patients with definite, unilateral Ménière's disease were included. According to the criteria of the Committee on Hearing and Equilibrium, all patients were in stage 1 or 2 of the disease, with largely preserved hearing function. OUTCOMES: All patients underwent clinical and audiologic testing before and 24 hours after intratympanic application of gadolinium-based contrast agent. The effects of the contrast medium on the hearing function were assessed by analysis of frequency thresholds, pure-tone average from 500 Hz to 3 kHz, and speech audiometry. RESULTS: Pure-tone average and single-frequency thresholds in audiometry showed no statistically significant difference after the application of intratympanic gadolinium-based contrast agent. Furthermore, speech audiometry scores remained stable after the application of the contrast agent. CONCLUSIONS: This study did not demonstrate clinically significant short-term effects of intratympanic application of gadolinium-based contrast agent on hearing function in patients with Ménière's disease in initial stages.

Biomechanical stability of sacroiliac screw osteosynthesis with and without cement augmentation.

BACKGROUND: Percutaneous sacroiliac (SI) screw fixation is the standard operative treatment of traumatic disruptions to the posterior pelvic ring. The technique offers good outcomes and early postoperative mobilization, which is vital in elderly patients with fragility fractures of the pelvis. While a double-screw technique has been shown to provide optimal biomechanical stability compared to a single-screw construct, anatomic variations and patient-specific characteristics may prevent the safe insertion of two SI screws. We aimed to determine whether cement augmentation of a single SI screw would provide biomechanical stability comparable to that of the double-screw technique. METHODS: Three sacroiliac screw osteosynthesis configurations were tested on 10 human cadaveric pelvis specimens: a single cannulated screw; two cannulated screws; and a single, cement-augmented cannulated screw. Displacement and stiffness of the anterior and posterior pelvic ring after fixation with each technique were measured under axial load. Results where compared using linear regression and paired t-tests. RESULTS: A single uncemented screw offered significantly worse stability in the anterior pelvis compared to a double-screw technique (P < 0.05) and to a single cement-augmented screw technique (P < 0.05). There was no significant difference in anterior pelvic ring stability between the single cement-augmented screw technique and the double-screw technique (P > 0.05). There was no significant difference in the stability of the posterior pelvic ring between the three techniques (P > 0.05). CONCLUSIONS: A single cement-augmented cannulated sacroiliac screw provides biomechanical stability similar to that of a non-augmented double-screw technique in the treatment of posterior pelvic ring fractures.

The T-pod is as stable as supraacetabular fixation using 1 or 2 Schanz screws in partially unstable pelvic fractures: a biomechanical study.

INTRODUCTION: Unstable fractures of the pelvis remain the predominant cause of severe hemorrhage, shock and early death in severely injured patients. The use of pelvic binders has become increasingly popular, particularly in the preclinical setting. There is currently insufficient evidence available about the stability of the pelvic binder versus supraacetabular fixation using 1 or 2 Schanz screws. We aimed to analyze the stability of the pelvic binder and supraacetabular fixateurs using either 1 or 2 Schanz screws in a cadaver model of an induced pelvic B-type fracture. MATERIALS AND METHODS: The study was undertaken in 7 human fresh-frozen cadaveric pelvises with induced AO-type B fractures. Three stabilization techniques were compared: T-POD (pelvic bandage), supraacetabular external fixator with 1 pin on each side and external fixator with 2 pins on each side. Stability and stiffness were analyzed in a biomechanical testing machine using a 5-step protocol with static and dynamic loading, dislocation data were retrieved by ultrasound sensors at the fracture sites. RESULTS: No significant differences in fracture fragment displacement were detected when using either the T-POD, a 1-pin external fixator or a 2-pin external fixator (P > 0.05). The average difference in displacement between the three methods was < 1 mm. CONCLUSIONS: Pelvic binders are suitable for reduction of pelvic B-type fractures. They provide stability comparable to that of supraacetabular fixators, independently of whether 1 or 2 Schanz screws per side are used. Pelvic binders provide sufficient biomechanical stability for transferring patients without the need to first replace them with surgically applied external fixators. However, soft tissue irritation has to be taken into consideration and prolonged wear should be avoided. LEVEL OF EVIDENCE: Level III.

Tape suture for stabilization of incomplete posterior pelvic ring fractures-biomechanical analysis of a new minimally invasive treatment for incomplete lateral compression pelvic ring fractures.

BACKGROUND: Incomplete lateral compression fractures (including AO Type B2.1) are among the most common pelvic ring injuries. Although the treatment of choice remains controversial, sacroiliac (SI) screws are commonly used for the operative treatment of incomplete lateral compression fractures of the pelvic ring. However, the disadvantages of SI screws include the risk of nerve root or blood vessel injury. Recently, tape sutures have been found useful as stabilizing material for the treatment of injuries of the syndesmosis, the rotator cuff and knee ligaments. In this current study, we aimed to test the biomechanical feasibility of tape sutures to stabilize the pelvis in the setting of AO Type B2.1 injury. METHODS: Six human cadaveric pelvises underwent cyclic loading to compare the biomechanical stability of different osteosynthesis methods in a B2.1 fracture model. The methods tested in this experiment were a FiberTape® suture and the currently established SI screw. A 3D ultrasound tracking system was used to measure fracture fragment motion. Linear regression was used to model displacement and stiffness at the posterior and anterior pelvic ring. RESULTS: At the posterior fracture site, the FiberTape® demonstrated similar displacement (2.2 ± 0.8 mm) and stiffness (52.2 ± 18.0 N/mm) compared to the sacroiliac screw (displacement 2.1 ± 0.6 mm, P >  0.999; stiffness 50.8 ± 13.0 N/mm, P > 0.999). Considering the anterior fracture site, the FiberTape® again demonstrated similar displacement (3.8 ± 1.3 mm) and stiffness (29.5 ± 9.0 N/mm) compared to the sacroiliac screw (displacement 2.9 ± 0.8 mm, P = 0.2196; stiffness 37.5 ± 11.5 N/mm, P = 0.0711). CONCLUSION: The newly presented osteosynthesis, the FiberTape®, shows promising results for the stabilization of the posterior pelvic ring in AO Type B2.1 lateral compression fractures compared to a sacroiliac screw osteosynthesis based on its minimal-invasiveness and the statistically similar biomechanical properties.

Influence of trait anxiety on inhibitory control in alcohol-dependent patients: simultaneous acquisition of ERPs and BOLD responses.

Alcohol-dependence is often associated with comorbid psychiatric symptoms. However, the results concerning the influence of these symptoms on cognitive functioning in alcoholism are still inconsistent. The aim of this study was to determine performance monitoring in healthy volunteers and alcohol-dependent patients, and to assess the influence of trait anxiety on these processes. Sixteen healthy volunteers and 16 detoxified alcohol-dependent patients completed an auditory go/nogo paradigm. Functional magnetic resonance imaging, event-related potentials and behavioral data were acquired simultaneously. The patients were classified by median split based on level of self-rated trait anxiety (state-trait anxiety inventory; STAI). The results showed no significant differences regarding inhibition-associated electrophysiological and behavioral responses between alcohol-dependent patients with high-trait anxiety scores and alcohol-addicts with low-STAI scores. However, the functional MRI data revealed elevated activations during the response inhibition task especially in the middle frontal gyrus (BA 6/9), the superior frontal gyrus (BA 6/8/9) and the right inferior frontal gyrus, as well as temporo-parietal brain regions in patients with high-trait anxiety compared to non-anxious alcohol-addicts. Patients and healthy controls showed comparable results with regard to neural and behavioral responses. These results suggest that inhibitory control capacities of alcohol-dependent patients are not consistent: alcohol-addicts with high-trait anxiety ratings showed elevated neural responses compared to patients without any comorbid psychiatric symptoms. This may indicate that comorbid psychiatric symptoms need to be considered when assessing brain responses in alcohol-dependent patients.

In Vivo Morphometric Analysis of Human Cranial Nerves Using Magnetic Resonance Imaging in Menière's Disease Ears and Normal Hearing Ears.

Analysis of neural structures in Menière's Disease (MD) is of importance, since a loss of such structures has previously been proposed for this patient group but has yet to be confirmed. This protocol describes a method of in vivo evaluation of neural changes especially well suitable for cranial nerve analysis using magnetic resonance imaging (MRI). MD-patients and normal hearing persons were examined in a 3-T MR-scanner using a scan protocol including strongly T2-weighted 3D gradient-echo-sequence (3D-CISS). In the patient group, MD was additionally confirmed using MRI-based assessment of endolymphatic hydrops. Morphometric analysis was performed using a freeware DICOM viewer. Evaluation of cranial nerves included measurements of cross-sectional areas (CSAs) of the nerves at different levels as well as orthogonal diametric measurements.

Measurement of basal forebrain atrophy in Alzheimer's disease using MRI.

Alzheimer's disease is characterized by the degeneration and loss of cholinergic neurones in the nucleus basalis Meynert, located within the substantia innominata at the ventral surface of the basal forebrain. An in vivo measure of morphological changes in the nucleus basalis Meynert would be of high relevance to better understand the structural correlate of cholinergic dysfunction in Alzheimer's disease. In this study, we applied a newly developed automated technique of image regression analysis, implemented through code written in Matlab 5.3 (MathWorks, Natick, MA), to the analysis of proton density weighted structural MRI of the basal forebrain from 13 patients with Alzheimer's disease (mean age = 77.5 years, SD = 4.4 years, 8 women) and 12 healthy elderly subjects (mean age = 62.3 years, SD = 5.6 years, 6 women). This technique allows searching a large portion of the substantia innominata for signal changes. We used corresponding MRI and histological sections of a post mortem brain to map the locations of basal forebrain cholinergic nuclei into the MRI standard space. Additionally, we used voxel-based morphometry, implemented in SPM2 (Wellcome Department of Imaging Neuroscience, London, UK) to determine correlations between signal changes in the substantia innominata and cortical grey matter atrophy in the patients with Alzheimer's disease. When matching the locations of signal reductions in the in vivo MRI to the template of basal nuclei based on the postmortem brain, signal intensity was decreased in areas corresponding to anterior lateral and anterior medial nucleus basalis Meynert and increased in the third ventricle, the transverse fissure and the optic tract in patients with Alzheimer's disease compared with controls. The reduction of the signal intensity in an area corresponding to the anterior lateral nucleus basalis Meynert was significantly correlated with reduced grey matter concentration in the bilateral prefrontal cortex, inferior parietal lobule and cingulate gyrus. Our findings suggest that signal changes occur in patients with Alzheimer's disease in the substantia innominata which may be related to the loss or degeneration of cholinergic neurones and correspond to regional cortical grey matter atrophy. If replicated in an independent sample, our technique may be useful to detect degeneration of basal forebrain cholinergic neurones in vivo.

Orbit-associated tumors: navigation and control of resection using intraoperative computed tomography.

OBJECT Treatment of skull base lesions is complex and usually requires a multidisciplinary approach. In meningioma, which is the most common tumor entity in this region, resection is considered to be the most important therapeutic step to avoid tumor recurrence. However, resection of skull base lesions with orbital or optic nerve involvement poses a challenge due to their anatomical structure and their proximity to eloquent areas. Therefore the main goal of surgery should be to achieve the maximum extent of resection while preserving neurological function. In the postoperative course, medical and radiotherapeutic strategies may then be successfully used to treat possible tumor residues. Methods to safely improve the extent of resection in skull base lesions therefore are desirable. The current study reports the authors' experience with the use of intraoperative CT (iCT) combined with neuronavigation with regard to feasibility and possible benefits of the method. METHODS Those patients with tumorous lesions in relationship to the orbit, sphenoid wing, or cavernous sinus who were surgically treated between October 2008 and December 2013 using iCT-based neuronavigation and in whom an intraoperative scan was obtained for control of resection were included. In all cases a second iCT scan was performed under sterile conditions after completion of navigation-guided microsurgical tumor resection. The surgical strategy was adapted accordingly; if necessary, resection was continued. RESULTS Twenty-three patients (19 with WHO Grade I meningioma and 4 with other lesions) were included. The most common clinical symptoms were loss of visual acuity and exophthalmus. Intraoperative control of resection by iCT was successfully obtained in all cases. Intraoperative imaging changed the surgical approach in more than half (52.2%) of these patients, either because iCT demonstrated unexpected residual tumor masses or because the second scan revealed additional tumor tissue that was not detected in the first scan due to overlay by osseous tumor parts; in these cases resection was continued. In the remaining cases resection was concluded as planned because iCT verified the surgeon's microscopic estimation of tumor resection status. Postoperative visual outcome was favorable in more than 80% of patients. CONCLUSIONS Intraoperative CT allows control of resection in case of uncertainty and can help to improve the extent of maximal safe resection, especially in case of osseous tumor parts and masses within the orbit.

Brain atrophy in primary progressive aphasia involves the cholinergic basal forebrain and Ayala's nucleus.

Primary progressive aphasia (PPA) is characterized by left hemispheric frontotemporal cortical atrophy. Evidence from anatomical studies suggests that the nucleus subputaminalis (NSP), a subnucleus of the cholinergic basal forebrain, may be involved in the pathological process of PPA. Therefore, we studied the pattern of cortical and basal forebrain atrophy in 10 patients with a clinical diagnosis of PPA and 18 healthy age-matched controls using high-resolution magnetic resonance imaging (MRI). We determined the cholinergic basal forebrain nuclei according to Mesulam's nomenclature and the NSP in MRI reference space based on histological sections and the MRI scan of a post-mortem brain in cranio. Using voxel-based analysis, we found left hemispheric cortical atrophy in PPA patients compared with controls, including prefrontal, lateral temporal and medial temporal lobe areas. We detected cholinergic basal forebrain atrophy in left predominant localizations of Ch4p, Ch4am, Ch4al, Ch3 and NSP. For the first time, we have described the pattern of basal forebrain atrophy in PPA and confirmed the involvement of NSP that had been predicted based on theoretical considerations. Our findings may enhance understanding of the role of cholinergic degeneration for the regional specificity of the cortical destruction leading to the syndrome of PPA.