The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform

Kohji Asakura - One of the best experts on this subject based on the ideXlab platform.

  • Prognostic factors of nasopharynx tumors investigated by MR imaging and the value of MR imaging in the newly published TNM staging.
    International journal of radiation oncology biology physics, 1999
    Co-Authors: Koh-ichi Sakata, Masato Hareyama, Mituharu Tamakawa, Atushi Oouchi, Mitsuo Sido, Hisayasu Nagakura, Hidenari Akiba, Kazumitsu Koito, Tetsuo Himi, Kohji Asakura
    Abstract:

    Abstract Purpose: To examine the usefulness of MR imaging for predicting local control of nasopharyngeal carcinoma (NPC) and the value of MR imaging in the newly published fifth edition of the TNM classification. Methods and Materials: We studied 29 patients with NPC with MR imaging and CT before and after treatment. Staging was done according to the fourth and newly published fifth editions of the International Union Against Cancer (UICC) staging system. The radiotherapy protocol was designed to deliver 66 to 68 Gy to the primary tumor and clinically involved nodes. Results: MR proved better than CT at identifying obliteration of the Pharyngobasilar Fascia, invasion of the sinus of Morgagni, through which the cartilaginous portion of the eustachian tube and the levator veli palatini muscle pass, invasion of the skull base, and metastases to lymph nodes in the carotid and retropharyngeal spaces. All seven patients without invasion of the Pharyngobasilar Fascia had local control. The local control rates of patients with invasion of the skull base were not good (60 to 73%). There was no apparent relationship between tumor volume determined by T1-weighted MR images and local control when the tumor volume was more than 20 cc. The newly published N staging system appears to successfully identify the high-risk group for distant metastasis as N3. In our series, four of five patients with N3 disease developed distant metastases. Conclusion: Deep infiltration of the tumor is a more important prognostic factor in NPC than tumor volume. Since the newly published T staging system requires a search for tumor invasion into soft tissue such as parapharyngeal space and bony structures, MR imaging may be indispensable for the newly published NPC staging system.

Takashi Nakagawa - One of the best experts on this subject based on the ideXlab platform.

  • The Fascial Layers Attached to the Skull Base: A Cadaveric Study
    World neurosurgery, 2019
    Co-Authors: Noritaka Komune, Satoshi Matsuo, Takashi Nakagawa
    Abstract:

    Objective A profound understanding of the relationship between the deep cervical Fasciae and the skull base is essential for skull base surgery. To our knowledge, there has been little research on the relationship between the deep cervical Fasciae and inferior surface of the skull base; thus, this study aims to examine the Fascial network of the skull base. Methods Two cadaveric heads are dissected to reveal the Fascial network of the skull base and 19 sides of cadaveric heads were used to reveal an anatomical variant of the pterygospinous and pterygoalar ligaments/muscles. Results The interpterygoid Fascia is attached to the skull base along the sphenopetrosal fissure and tympanosquamous suture. The tensor vascular styloid Fascia extends from the inferior border of the tensor veli palatini and covers the tympanic bone and styloid apparatus laterally. The Pharyngobasilar Fascia attaches to the pharyngeal tubercle on the inferior surface of the basilar part of the occipital bone and petro-occipital synchondrosis. In the middle of the clivus, we found thick fibrocartilaginous tissue and the prevertebral Fascia fused to this area. Fascia of the longus capitis, the tensor-vascular styloid Fascia, and stylopharyngeal Fascia extend laterally and form the complex Fascial network around the internal jugular vein and the internal carotid artery. The carotid sheath attaches anteriorly to the vaginal process and posteriorly to the fibrocartilaginous tissue around the jugular foramen and carotid canal. Conclusions This study comprehensively exposes the Fascial network of the skull base. Our cadaveric dissection findings support those from previous imaging-anatomical studies. Precise knowledge of these Fascial layers is essential for accurate diagnosis and understanding the spread of disease, as well as helping skull base surgeons safely perform challenging procedures.

Peter H Hwang - One of the best experts on this subject based on the ideXlab platform.

  • endoscopic endonasal anatomy of the nasopharynx in a cadaver model
    International Forum of Allergy & Rhinology, 2013
    Co-Authors: Adam M Becker, Peter H Hwang
    Abstract:

    Background Nasopharyngectomy is an accepted treatment for recurrent nasopharyngeal carcinoma following radiation with or without chemotherapy. Traditionally, the nasopharynx has been approached through relatively invasive “open” techniques including transpalatal, maxillary swing, and trans-mandibular-pterygoid approaches. Contemporary management has included the use of endoscopic techniques to exenterate tumors in this location. The purpose of the present study is to describe the endoscopic anatomy of this region through cadaveric dissection and to characterize the technical limitations of the approach. Methods Five fresh cadaveric heads were dissected to study the endoscopic anatomy of the nasopharynx and associated structures. Results Endoscopic dissection of the nasopharynx was completed in all 5 specimens. Nasopharyngeal anatomy including the buccopharyngeal Fascia, Pharyngobasilar Fascia, superior constrictor, longus capitus, longus coli, fossa of Rosenmuller, basisphenoid, auditory torus, and internal carotid artery were characterized. Conclusion Surgical access to the nasopharynx has posed significant challenges in the treatment of recurrent or persistent nasopharyngeal carcinoma. This study demonstrated that endoscopic dissection of this region is feasible and has the potential to completely exenterate these lesions.

Koh-ichi Sakata - One of the best experts on this subject based on the ideXlab platform.

  • Prognostic factors of nasopharynx tumors investigated by MR imaging and the value of MR imaging in the newly published TNM staging.
    International journal of radiation oncology biology physics, 1999
    Co-Authors: Koh-ichi Sakata, Masato Hareyama, Mituharu Tamakawa, Atushi Oouchi, Mitsuo Sido, Hisayasu Nagakura, Hidenari Akiba, Kazumitsu Koito, Tetsuo Himi, Kohji Asakura
    Abstract:

    Abstract Purpose: To examine the usefulness of MR imaging for predicting local control of nasopharyngeal carcinoma (NPC) and the value of MR imaging in the newly published fifth edition of the TNM classification. Methods and Materials: We studied 29 patients with NPC with MR imaging and CT before and after treatment. Staging was done according to the fourth and newly published fifth editions of the International Union Against Cancer (UICC) staging system. The radiotherapy protocol was designed to deliver 66 to 68 Gy to the primary tumor and clinically involved nodes. Results: MR proved better than CT at identifying obliteration of the Pharyngobasilar Fascia, invasion of the sinus of Morgagni, through which the cartilaginous portion of the eustachian tube and the levator veli palatini muscle pass, invasion of the skull base, and metastases to lymph nodes in the carotid and retropharyngeal spaces. All seven patients without invasion of the Pharyngobasilar Fascia had local control. The local control rates of patients with invasion of the skull base were not good (60 to 73%). There was no apparent relationship between tumor volume determined by T1-weighted MR images and local control when the tumor volume was more than 20 cc. The newly published N staging system appears to successfully identify the high-risk group for distant metastasis as N3. In our series, four of five patients with N3 disease developed distant metastases. Conclusion: Deep infiltration of the tumor is a more important prognostic factor in NPC than tumor volume. Since the newly published T staging system requires a search for tumor invasion into soft tissue such as parapharyngeal space and bony structures, MR imaging may be indispensable for the newly published NPC staging system.

Harpreet Hyare - One of the best experts on this subject based on the ideXlab platform.

  • The anatomy of nasopharyngeal carcinoma spread through the Pharyngobasilar Fascia to the trigeminal mandibular nerve on 1.5 T MRI
    Surgical and Radiologic Anatomy, 2010
    Co-Authors: Harpreet Hyare, Jonathan J. Wisco, Ghassen Alusi, Marc Cohen, Vishad Nabili, Elliot Abemayor, Claudia F. E. Kirsch
    Abstract:

    Purpose To analyze, from 1.5 Tesla (T) MRI clinical cases, anatomical accessibility of nasopharyngeal tumors through the Pharyngobasilar Fascia (PBF) to the mandibular nerve for potential perineural spread. Methods A 6-year retrospective review of 1.5 T MR images were rated for tumor involvement of Fascial planes and perineural spread in 15 consecutive patients (10 female, 5 male; mean age 45.8 years, range 19–86) with histopathologically proven tumors of the nasopharynx and referrals for radiotherapy due to intracranial extension. Results Nasopharyngeal tumors were best appreciated on T1 fat-saturated, post-gadolinium MRI. Tumors extended through the sinus of Morgagni in all cases. This sinus is a defect in the PBF through which the Eustachian tube and levator veli palatini muscle gain access to the nasopharynx. In six patients, the PBF and tensor veli palatini Fascia were breached anteriorly with tumor infiltration of the tensor veli palatini and medial pterygoid muscles. In 13 cases, tumor breached the posterolateral PBF with extension into the poststyloid parapharyngeal space. In three subjects, 3 T images were also acquired and exhibited superior delineation of the anatomy and perineural tumor spread. Conclusions At 1.5 T, images showed nasopharyngeal tumors extending through the PBF into the masticator and parapharyngeal spaces, with access to the mandibular nerve and potential for perineural spread. At 3 T, soft tissue resolution appeared superior to 1.5 T. This may reflect not only the increased field strength, but an improved technique and matrix, and future studies are necessary to confirm this observation. Awareness of this anatomy for radiation and surgical planning is essential and may improve the ability for obtaining negative margins, and increasing overall survival.

  • The anatomy of nasopharyngeal carcinoma spread through the Pharyngobasilar Fascia to the trigeminal mandibular nerve on 1.5 T MRI.
    Surgical and radiologic anatomy : SRA, 2010
    Co-Authors: Harpreet Hyare, Jonathan J. Wisco, Ghassen Alusi, Marc Cohen, Vishad Nabili, Elliot Abemayor, Claudia Kirsch
    Abstract:

    Purpose To analyze, from 1.5 Tesla (T) MRI clinical cases, anatomical accessibility of nasopharyngeal tumors through the Pharyngobasilar Fascia (PBF) to the mandibular nerve for potential perineural spread.