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Copyright of Acta Universitaria is the property of Universidad de Guanajuato/Acta Universitaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background Hereditary head and neck paragangliomas ( HNPGLs) account for at least 35% of all HNPGLs, most commonly due to germline mutations in SDHx susceptibility genes. Several studies about sympathetic paragangliomas have shown that 18 F-FDG PET/CT was not only able to detect and localize tumours, but also to characterize tumours (18 F-FDG uptake being linked to SDHx mutations). However, the data concerning 18 F-FDG uptake specifically in HNPGLs have not been addressed. The aim of this study was to evaluate the relationship between 18 F-FDG uptake and the SDHx mutation status in HNPGL patients. Methods 18 F-FDG PET/CT from sixty HNPGL patients were evaluated. For all lesions, we measured the maximum standardized uptake values ( SUVmax), and the uptake ratio defined as HNPGL- SUVmax over pulmonary artery trunk SUVmean ( SUVratio). Tumour sizes were assessed on radiological studies. Results Sixty patients (53·3% with SDHx mutations) were evaluated for a total of 106 HNPGLs. HNPGLs- SUVmax and SUVratio were highly dispersed (1·2-30·5 and 1·0-17·0, respectively). The HNPGL 18 F-FDG uptake was significantly higher in SDHx versus sporadic tumours on both univariate and multivariate analysis ( P = 0·002). We developed two models for calculating the probability of a germline SDHx mutation. The first one, based on a per-lesion analysis, had an accuracy of 75·5%. The second model, based on a per-patient analysis, had an accuracy of 80·0%. Conclusions 18F-FDG uptake in HNPGL is strongly dependent on patient genotype. Thus, the degree of 18F-FDG uptake in these tumours can be used clinically to help identify patients in whom SDHx mutations should be suspected. [ABSTRACT FROM AUTHOR]

Aims and methods To evaluate the clinical value of 18 F-fluorodihydroxyphenylalanine (18 F- FDOPA) PET in relation to tumour localization and the patient's genetic status in a large series of pheochromocytoma/paraganglioma ( PHEO/ PGL) patients and to discuss in detail false-negative results. A retrospective study of PGL patients who were investigated with 18 F- FDOPA PET or PET/ CT imaging in two academic endocrine tumour centres was conducted ( La Timone University Hospital, Marseilles, France and National Institutes of Health ( NIH), Bethesda, MD, USA). Results One hundred sixteen patients (39·7% harbouring germline mutations in known disease susceptibility genes) were evaluated for a total of 195 PHEO/ PGL foci. 18 F- FDOPA PET correctly detected 179 lesions (91·8%) in 107 patients (92·2%). Lesion-based sensitivities for parasympathetic PGLs (head, neck, or anterior/middle thoracic ones), PHEOs, and extra-adrenal sympathetic (abdominal or posterior thoracic) PGLs were 98·2% [96·5% for Timone and 100% for NIH], 93·9% [93·8 and 93·9%] and 70·3% [47·1 and 90%] respectively ( P < 0·001). Sympathetic (adrenal and extra-adrenal) SDHx-related PGLs were at a higher risk for negative 18F- FDOPA PET than non- SDHx-related PGLs (14/24 vs 0/62, respectively, P < 0·001). In contrast, the risk of negative 18F- FDOPA PET was lower for parasympathetic PGLs regardless of the genetic background (1/90 in SDHx vs 1/19 in non- SDHx tumours, P = 0·32). 18F- FDOPA PET failed to detect two head and neck PGLs ( HNPGL), likely due to their small size, whereas most missed sympathetic PGL were larger and may have exhibited a specific 18F- FDOPA-negative imaging phenotype. 18F- FDG PET detected all the missed sympathetic lesions. Conclusions 18F- FDOPA PET appears to be a very sensitive functional imaging tool for HNPGL regardless of the genetic status of the tumours. Patients with false-negative tumours on 18F- FDOPA PET should be tested for SDHx mutations. [ABSTRACT FROM AUTHOR]

Copyright of Revista Latinoamericana de Patología Clínica y Medicina de Laboratorio is the property of Federacion Mexicana de Patologia Clinica y de la Asociacion Latinoamericana de Patologia Clinica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this prospective study was to compare the diagnostic value of [F]FDOPA-PET and [In]pentetreotide-SPECT somatostatin receptor scintigraphy (SRS) in patients with nonmetastatic extra-adrenal paragangliomas (PGLs). Twenty-five consecutive unrelated patients who were known or suspected of having nonmetastatic extra-adrenal PGLs were prospectively evaluated with SRS and [F]FDOPA-PET. I-MIBG and [F]FDG-PET were added to the work-up in patients with a personal or familial history of PGL, predisposing mutations, abdominal PGLs, metanephrine hypersecretion and abdominal foci on SRS and/or [F]FDOPA-PET. SRS correctly detected 23/45 lesions of which 20 were head or neck lesions (H&N) and 3 were abdominal lesions. [F]FDOPA-PET detected significantly more lesions than SRS (39/45, P < 0·001). Both SRS and F-DOPA-PET detected significantly more H&N than abdominal lesions (66·7% vs 20%, P = 0·003 and 96·7% vs 67%, P = 0·012, respectively). In two patients with the succinate dehydrogenase D (SDHD) mutation, [F]FDOPA-PET missed five abdominal PGLs which were detected by the combination of SRS, [I]MIBG and [F]FDG-PET. A lesion-based analysis using a forward stepwise logistic regression model demonstrates that size ≤ 10 mm ( P = 0·002) and abdominal lesions ( P = 0·031) were independently associated with '[F]FDOPA-PET diagnosis only'. In turn, a previous history of surgery and/or the presence of germline mutation was associated with lower lesion size ( P = 0·001). The sensitivity of SRS for localizing parasympathetic PGLs is lower than originally reported, and [F]FDOPA-PET is better than SRS for localizing small lesions. SRS should be replaced by [F]FDOPA-PET as the first-line imaging procedure in H&N PGL, especially in patients at risk of multifocal disease (predisposing mutations and or previous history of surgery). [ABSTRACT FROM AUTHOR]

Conclusion: After initial contact of the active middle ear implant (AMEI) on the incus, significant increases in device performance can be achieved intraoperatively without affecting residual hearing by additional static loading of the incus with 62 μm (quarter turn) to 125 μm (half turn) increments via an adjustment screw. Objectives: To assess the performance gains of driving the incus with an AMEI under increasing static loads in cadaveric temporal bones. Methods: Incus drive efficacy was assessed using laser Doppler velocimetry measurements of stapes velocities over a frequency range of 0.25 to 8 kHz. Results were compared to stapes velocities following acoustic stimulation via insert earphone. Maximum equivalent ear canal sound pressure level (LEmax) and residual hearing loss after initial loading of the AMEI (first contact) were compared in each temporal bone. Additional increases in incus load were induced by turning an adjustment screw in quarter turn steps, corresponding to 62 μm increments per step. LEmaxand residual hearing loss were reassessed after each step. For each temporal bone, experiments were repeated for three different AMEIs. Results: On average across bones, incus stimulation upon initial contact produced an LEmaxof 125, 127, and 121 dB SPL and residual hearing losses of -2, -1, and -1 dB with respect to unloaded, unaided conditions for the three AMEIs, respectively. Across bones and transducers, increasing static transducer load by incrementing the AMEI up to 125 μm significantly improved performance without affecting residual hearing loss. Loading beyond 125 μm (half turn) did not improve performance but significantly increased residual hearing loss. [ABSTRACT FROM AUTHOR]

The level of success of neurovascular decompression in ponto-cerebellar angle for hemifacial spasm and trigeminal neuralgia has already established the reality of the pathology to explain such symptoms. However, cochlear nerve compression syndrome by vascular loop is still a controversial topic. We have performed a retrospective cases review with long-term follow-up (5–7 years) concerning the results of microvascular decompression surgery of the cochlear nerve via an endoscopy assisted retrosigmoid approach on 15 patients suffering from unilateral incapacitating tinnitus with abnormal auditory brainstem response and an offending vessel on magnetic resonance imaging. During the surgery, a vascular compression was found on every patient. In a long-term follow-up, 53.3% (8 cases) of our tinnitus cases improved and 20% (3 cases) of them were completely cured. The ABR returned to normal in all patients who had good clinical results (diminished or disappeared tinnitus). When a vertebral artery loop (5 cases) was concerned we obtained 80% of good clinical results. No one showed amelioration or sudden aggravation of their hearing. Three cases required surgical correction of cerebrospinal fluid leak and one case developed spontaneously regressive swallowing problems. Such microvascular decompression surgery of the cochlear nerve appears to be successful in treating incapaciting tinnitus in particular when a vertebral artery loop is observed. Therefore, in such a case, one might recommend neurovascular decompression surgery, keeping in mind that the complications of this surgery should be minimized by a careful closure of the retrosigmoid approach. In order to ensure a better selection of patient more accurate cochlear nerve monitoring and functional MRI should be a promising assessment. [ABSTRACT FROM AUTHOR]

Neurovascular compression syndromes are nowadays quite fully understood. Imaging findings, symptoms, and surgical treatment are becoming routine. From these, hemifacial spasm and trigeminal neuralgia are the 2 most common conditions related to neurovascular compression syndrome. The initial surgical procedure done in 1965 by Janetta became more routinely acceptable in the 90s, with the concept of mini-invasive surgery using retrosigmoid approach thanks to the association of endoscope and microscope during surgery that led to more efficient decompressive surgery. Back to the huge experience of the department headed by Professor Jacques MAGNAN (that started the minimal invasive procedure in 1974), we demonstrated that the systematic use of the endoscopy improved the quality of the visualization of the conflict, reducing mobilization of cerebellum and brainstem structure and drastically improving the final results. Endoscopy has, here, a valuable role, since it allows checking the REZ of the facial nerve without extensive dissection of the acoustico-facial nerve bundle. Hence, the dissection of the flocculus, which hides the REZ of the facial nerve, is one of the riskiest factors for additional injury of the cochlear nerve, leading to various degrees of sensorineural hearing loss. In addition, checking the REZ of the facial nerve before manipulating the arteries and arachnoid layers prevent accidental mobilization of the offending vessel, which may be a cause of misdiagnosis. Eventually, the quality of the decompression realized is controlled under the final endoscopy of the CPA. We will be presenting a summary of the experience of more than 600 patients operated from hemifacial spasm, demonstrating the benefit of endoscopic using video-case presentation and discussing the feasibility of carrying fully endoscopic decompression of neurovascular compression syndrome. [ABSTRACT FROM AUTHOR]