Tissue Acceleration as a Novel Metric for Surgical Performance During Carotid Endarterectomy.

BACKGROUND AND OBJECTIVES: Gentle tissue handling to avoid excessive motion of affected fragile vessels during surgical dissection is essential for both surgeon proficiency and patient safety during carotid endarterectomy (CEA). However, a void remains in the quantification of these aspects during surgery. The video-based measurement of tissue acceleration is presented as a novel metric for the objective assessment of surgical performance. This study aimed to evaluate whether such metrics correlate with both surgeons' skill proficiency and adverse events during CEA. METHODS: In a retrospective study including 117 patients who underwent CEA, acceleration of the carotid artery was measured during exposure through a video-based analysis. Tissue acceleration values and threshold violation error frequencies were analyzed and compared among the surgeon groups with different surgical experience (3 groups: novice , intermediate , and expert ). Multiple patient-related variables, surgeon groups, and video-based surgical performance parameters were compared between the patients with and without adverse events during CEA. RESULTS: Eleven patients (9.4%) experienced adverse events after CEA, and the rate of adverse events significantly correlated with the surgeon group. The mean maximum tissue acceleration and number of errors during surgical tasks significantly decreased from novice, to intermediate, to expert surgeons, and stepwise discriminant analysis showed that the combined use of surgical performance factors could accurately discriminate between surgeon groups. The multivariate logistic regression analysis revealed that the number of errors and vulnerable carotid plaques were associated with adverse events. CONCLUSION: Tissue acceleration profiles can be a novel metric for the objective assessment of surgical performance and the prediction of adverse events during surgery. Thus, this concept can be introduced into futuristic computer-aided surgeries for both surgical education and patient safety.

Cerebrospinal fluid-contacting neuron tracing reveals structural and functional connectivity for locomotion in the mouse spinal cord.

Cerebrospinal fluid-contacting neurons (CSF-cNs) are enigmatic mechano- or chemosensory cells lying along the central canal of the spinal cord. Recent studies in zebrafish larvae and lampreys have shown that CSF-cNs control postures and movements via spinal connections. However, the structures, connectivity, and functions in mammals remain largely unknown. Here we developed a method to genetically target mouse CSF-cNs that highlighted structural connections and functions. We first found that intracerebroventricular injection of adeno-associated virus with a neuron-specific promoter and Pkd2l1-Cre mice specifically labeled CSF-cNs. Single-cell labeling of 71 CSF-cNs revealed rostral axon extensions of over 1800 µm in unmyelinated bundles in the ventral funiculus and terminated on CSF-cNs to form a recurrent circuitry, which was further determined by serial electron microscopy and electrophysiology. CSF-cNs were also found to connect with axial motor neurons and premotor interneurons around the central canal and within the axon bundles. Chemogenetic CSF-cNs inactivation reduced speed and step frequency during treadmill locomotion. Our data revealed the basic structures and connections of mouse CSF-cNs to control spinal motor circuits for proper locomotion. The versatile methods developed in this study will contribute to further understanding of CSF-cN functions in mammals.

High-contrast high-resolution imaging of posttraumatic mandibular nerve by 3DAC-PROPELLER magnetic resonance imaging: correlation with the severity of sensory disturbance.

OBJECTIVE: Magnetic resonance neurography reveals abnormal morphologies of regenerated nerves and overgrown connective tissue in injured trigeminal nerves, suggesting neuroma formation. We hypothesized that such deformities and scar formation contribute to pain symptoms. STUDY DESIGN: High-contrast high-resolution magnetic resonance imaging was utilized to evaluate the inferior alveolar nerve and lingual nerve following traumatic injury in 19 patients. The relationship between the morphologic classification and severity of the sensory disorder was assessed. RESULTS: In all cases, 3-dimensional anisotropy contrast periodically rotated overlapping parallel lines with enhanced reconstruction (3DAC-PROPELLER) successfully revealed the inner structures within the lesion. The isolated type represented the normal course of the nerve isolated from scar-like tissue (8 cases), whereas the deformity type included the deformed nerve either within scar-like tissue or by itself, unassociated with surrounding scar-like tissue (9 cases). In the remaining 2 cases, the nerve tissue and scar-like tissue were incorporated. Patients with the deformity type exhibited significantly more severe pain symptoms compared with patients with the isolated type. CONCLUSIONS: Overgrown connective tissue does not necessarily block regenerating nerves and itself may not cause pain. The morphologic findings on the 3DAC-PROPELLER were relevant to the severity of pain symptoms.

[Application of brain diffusion-weighted imaging performed using readout segmentation of long variable echo trains].

We report the preliminary use of the readout segmentation of long variable echo trains(RESOLVE)sequence, a novel magnetic resonance(MR)scanning technique based on a readout segmented echo planar imaging(EPI)strategy. RESOLVE enables high-resolution diffusion-weighted imaging(DWI)by minimizing susceptibility distortions and T2* blurring. The software for this sequence was provided by Siemens AG, Germany. Previously, we determined appropriate sequence parameters to obtain sufficiently high-resolution images through phantom studies. Then, we applied the sequence to some clinical cases with neurological disorders and analyzed the RESOLVE-DWI data with diffusion tensor imaging(DTI)techniques. In this article, we report clinical application of the RESOLVE sequence in two cases, one with cerebellar infarction and one with an intracranial epidermoid cyst. In both cases, RESOLVE-DWI clearly exposed structures that were obscured or severely distorted by artifacts on usual single-shot EPI-DWI. DTI analyses for RESOLVE-DWI data provided detailed information about fiber tracts and cranial nerves.

Protracted delay in taste sensation recovery after surgical lingual nerve repair: a case report.

INTRODUCTION: Lingual nerve injury is sometimes caused by dental treatment. Many kinds of treatment have been reported, but many have exhibited poor recovery. Here the authors report changes in somatosensory and chemosensory impairments during a long-term observation after lingual nerve repair. CASE PRESENTATION: A 30-year-old Japanese woman claimed dysesthesia and difficulty eating. Quantitative sensory test results indicated complete loss of sensation in the right side of her tongue. She underwent a repair surgery involving complete resection of her lingual nerve using a polyglycolic acid tube containing collagen 9 months after the injury. A year after the operation, her mechanical touch threshold recovered, but no other sensations recovered. Long-term observation of her somatosensory and chemosensory function after the nerve repair suggested that recovery of taste sensation was greatly delayed compared with that of somatosensory function. CONCLUSION: This case shows characteristic changes in somatosensory and chemosensory recoveries during 7 postoperative years and suggests that taste and thermal sensations require a very long time to recover after repair surgery.

Morphologic evaluation of the inferior alveolar nerve in patients with sensory disorders by high-resolution 3D volume rendering magnetic resonance neurography on a 3.0-T system.

OBJECTIVE: The objective of this study was to evaluate the inferior alveolar nerve (IAN) morphologically in patients with symptomatic posttraumatic sensory disorders using magnetic resonance imaging (MRI) on a high-field system. STUDY DESIGN: Sixteen patients who complained of persistent sensory disturbance attributed to unilateral IAN injury participated in the investigation. High-resolution 3-dimensional volume rendering magnetic resonance neurography was performed on a 3.0-T MRI system. RESULTS: In 15 (94%) of 16 patients, high-resolution 3-dimensional volume rendering magnetic resonance neurography demonstrated morphologic abnormalities of the IAN as well as connective tissue overgrowth. These findings were confirmed intraoperatively (6 patients) and histopathologically (5 patients). The duration of sensory disturbance correlated significantly with the pattern of morphologic deformity and connective tissue overgrowth. CONCLUSIONS: The current study clearly demonstrated that appropriate application of clinical MRI techniques can significantly improve the diagnosis and potential treatment of patients with orofacial peripheral nerve disorders.

Insidious extension of pituitary prolactinoma: two can't-miss findings depicted on a 3.0-T MR system.

BACKGROUND: In this article, we present two can't-miss findings on preoperative magnetic resonance imaging (MRI) using a 3.0-T MR system resulting in a better surgical option in prolactinoma treatment after emergent of dopamine agonists. METHODS: We reviewed six cases of pituitary prolactinoma; each had vague or occult bulk of adenoma on 1.5-T MR imaging, which were finally confirmed by surgery. Four cases were preoperatively examined with a 3.0-T MR imaging system. With the 3.0-T MR system, 3-dimension-anisotropy-contrast (3DAC) MR imaging and 3-dimension fast spoiled gradient recalled acquisition in the steady state (3D-FSPGR) imaging were used for depiction of the adenoma. RESULTS: 3DAC imaging revealed cavernous sinus (CS) pathology in three cases, and multiplanar reconstruction of 3D-FSPGR imaging revealed normal pituitary gland and invasive adenoma into the CS in three cases and creeping extension up to the contralateral side of the CS invasion in four cases. CONCLUSIONS: Two can't-miss findings: (1) intrasellar creeping extension up to the opposite side of the adenoma main body and (2) intracavernous-localized adenoma with indistinct intrasellar mass should be carefully considered when neurosurgeons perform adenomectomy for patients with prolactinoma, even in cases of microprolactinoma.

Preoperative depiction of cavernous sinus invasion by pituitary macroadenoma using three-dimensional anisotropy contrast periodically rotated overlapping parallel lines with enhanced reconstruction imaging on a 3-tesla system.

OBJECTIVES: Three-dimensional anisotropy contrast (3DAC) magnetic resonance (MR) imaging provides clear depiction of neuronal fibers. The aim of this study was to identify intracavernous cranial nerves in patients with pituitary macro-adenoma and in healthy volunteers by using 3DAC MR imaging on a 3-tesla system and to preoperatively predict cavernous sinus invasion by pituitary macroadenoma. METHODS: Thirty-three patients (cavernous sinuses in 66 sides) with pituitary macroadenomas and 25 healthy volunteers (50 sides) participated in this study. Coronal 3DAC MR images constructed from diffusion weighted images, acquired with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) sequences, and T2-weighted reverse images were obtained at the same anatomical locations using a 3-tesla MR imaging system. Attempts were made to identify the cranial nerves. RESULTS: The oculomotor and ophthalmic/maxillary nerves were preoperatively identified in all sides (66 sides in patients and 50 sides in healthy volunteers) on 3DAC MR images. In the 33 patients, cavernous sinus invasion was revealed in 10 (12 [18.2%] of 66 sides) by intraoperative endoscopic observation. Coronal 3DAC MR images revealed that the oculomotor nerves were half surrounded with adenoma in all 12 of these sides, and the ophthalmic/maxillary nerves were half encapsulated with tumor (sensitivity/specificity: 100%/100% and 83%/100%, respectively). CONCLUSIONS: Preoperative evaluation of pituitary macroadenomas using 3DAC PROPELLER MR imaging on a 3-tesla system is likely to be a powerful noninvasive method of detecting cavernous sinus invasion, which can potentially dominate the therapeutic strategy for these lesions.

Three-dimensional anisotropy contrast periodically rotated overlapping parallel lines with enhanced reconstruction (3DAC PROPELLER) on a 3.0T system: a new modality for routine clinical neuroimaging.

BACKGROUND: Clinical magnetic resonance imaging (MRI) has recently entered the "high-field" era, and systems equipped with 3.0-4.0T superconductive magnets are becoming the gold standard for diagnostic imaging. While higher signal-to-noise ratio (S/N) is a definite advantage of higher field systems, higher susceptibility effect remains to be a significant trade-off. To take advantage of a higher field system in performing routine clinical images of higher anatomical resolution, we implemented a vector contrast image technique to 3.0T imaging, three-dimensional anisotropy contrast (3DAC), with a PROPELLER (Periodically Rotated Overlapping Parallel Lines with Enhanced Reconstruction) sequence, a method capable of effectively eliminating undesired artifacts on rapid diffusion imaging sequences. METHODS: One hundred subjects (20 normal volunteers and 80 volunteers with various central nervous system diseases) participated in the study. Anisotropic diffusion-weighted PROPELLER images were obtained on a General Electric (Waukesha, WI, USA) Signa 3.0T for each axis, with b-value of 1100 sec/mm(2). Subsequently, 3DAC images were constructed using in-house software written on MATLAB (MathWorks, Natick, MA, USA). RESULTS: The vector contrast allows for providing exquisite anatomical detail illustrated by clear identification of all major tracts through the entire brain. 3DAC images provide better anatomical resolution for brainstem glioma than higher-resolution T2 reversed images. Degenerative processes of disease-specific tracts were clearly identified as illustrated in cases of multiple system atrophy and Joseph-Machado disease. CONCLUSION: Anatomical images of significantly higher resolution than the best current standard, T2 reversed images, were successfully obtained. As a technique readily applicable under routine clinical setting, 3DAC PROPELLER on a 3.0T system will be a powerful addition to diagnostic imaging.

Diffusion tensor analysis of peritumoral edema using lambda chart analysis indicative of the heterogeneity of the microstructure within edema.

OBJECT: Histopathological studies indicate that cerebral edema associated with tumors (peritumoral edema) does not represent a single pathophysiological or clinical entity. In this study the authors investigated peritumoral edema by performing lambda chart analysis (LCA), a noninvasive technique that can be used to make visible and analyze apparent water diffusivity in tissues in vivo, and assessed the utility of LCA in differentiating high-grade gliomas from nonglial tumors. METHODS: The water diffusivity characteristics of peritumoral edema associated with four tumor groups-12 high-grade gliomas, five low-grade gliomas, 11 metastatic tumors, and 15 meningiomas-were assessed in 43 patients by performing magnetic resonance imaging with the aid of a 3-tesla magnetic resonance imaging system. In all tumor groups, peritumoral edema exhibited greater trace values and reduced anisotropy compared with normal white matter. Edema associated with high-grade gliomas had significantly higher trace values than edema associated with the other three tumor groups, although the anisotropic angles of those groups were comparable. CONCLUSIONS: Lambda chart analysis identified two distinct types of peritumoral edema: edema associated with high-grade gliomas and edema associated with low-grade gliomas or nonglial tumors. The apparent water diffusivity was significantly greater in high-grade gliomas, whereas the anisotropy in these lesions was comparable to that of edema in other tumors. These findings indicated that water movement in areas of edema, predominantly in the extracellular spaces, was less restricted in high-grade gliomas, a phenomenon that likely reflected the destruction of the extracellular matrix ultrastructure by malignant cell infiltration and consequently greater water diffusion. Although preliminary, this study indicates that LCA could be used as a clinical tool for differentiating high-grade gliomas and for evaluating the extent of cellular infiltration.