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Chong VF, Mukherji SK, Ng SH, Ginsberg LE, Wee JT, Sham JS, O'Sullivan B. Nasopharyngeal carcinoma: review of how imaging affects staging. J Comput Assist Tomogr 1999; 23:984-93. [PMID: 10589583 DOI: 10.1097/00004728-199911000-00032] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Imaging plays an important role in the staging of carcinoma of the nasopharynx. Accurate staging is necessary as the treatment is directly dependent on stage. Clinical examination provides information on mucosal involvement but is unable to determine the deep extension or presence of skull base invasion or intracranial spread. The 1997 International Union Against Cancer (UICC) and American Joint Committee on Cancer (AJCC) staging manuals were a collaborative project that provided a unified classification for nasopharyngeal carcinoma (NPC). The majority of staging can be identified only on imaging and not by clinical examination. The intent of this article is to provide information on the specific imaging findings that will directly affect the stage and treatment of NPC.
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Abstract
Nasopharyngeal carcinoma (NPC) is a malignant tumor that shows distinct distributions into geographical and into well-defined high-risk ethnic groups. Radiation therapy is the mainstay of treatment, and imaging plays a central role in tumor mapping and post-treatment follow-up. Magnetic resonance imaging is better than computed tomography in demonstrating tumor extent, tumor recurrence, and postradiation complications. However, differentiating postradiation changes from tumor recurrence may be difficult using magnetic resonance imaging. Mucosal recurrence is best detected with endoscopy.
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Chong VF, Rumpel H, Aw YS, Ho GL, Fan YF, Chua EJ. Temporal lobe necrosis following radiation therapy for nasopharyngeal carcinoma: 1H MR spectroscopic findings. Int J Radiat Oncol Biol Phys 1999; 45:699-705. [PMID: 10524425 DOI: 10.1016/s0360-3016(99)00236-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To observe the patterns of radiation-induced temporal lobe necrosis (TLN) following radiation therapy for nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS Twenty-five proton magnetic resonance spectroscopic (1H MRS) examinations were acquired from 13 healthy adult volunteers for comparison with data from the patient population. There were 18 patients (28 spectra) with radiologic evidence of TLN and all patients were confirmed cases of NPC treated with radiation therapy. Six patients (33%) had a single treatment while 12 (67%) patients had two treatments. All 1H MRS examinations were performed on a 2-T whole body system (Bruker) using the point-resolved spectroscopy (PRESS) method with TE = 135 ms, TR = 3000 ms, and data processed automatically using the LCModel software package for metabolite quantification. RESULTS The N-acetyl-aspartate (NAA) levels were reduced in all except one spectrum (96%). Choline (Cho) was increased in 3 (11%), normal in 4 (14%), and reduced in 21 (75%) spectra. The creatine (Cr) level was normal in 8 (29%) spectra and reduced in 20 (71%) spectra. In four patients with normal imaging findings 1H MRS was abnormal. CONCLUSION 1H MRS can characterize radiation-induced TLN. Spectra with increased Cho can be mistaken for neoplasm. Spectroscopy can also identify metabolic derangement before imaging.
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Abstract
The orbital apex, formed by the superior orbital fissure and optic canal, is the cross-road between the orbit and the intracranial structures. Pathological processes may extend intracranially via the superior orbital fissure and vice versa. In addition to intrinsic soft tissue lesions, various pathological processes may involve the surrounding osseous anatomy. Malignant lesions arising from adjacent structures or from haematogeneous metastasis may also infiltrate this region.
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Abstract
PURPOSE This study documents the imaging findings of parotid gland involvement in nasopharyngeal carcinoma (NPC). METHOD This study reviewed the film records of 1,916 patients with NPC seen over a 5 year period. There were 27 (1.4%) patients with parotid involvement. There were 27 CT and 4 MR studies, and the pattern of involvement was categorized into the following groups: (1) parotid nodal involvement; (2) parotid invasion from extracapsular cervical nodal spread; (3) direct invasion by NPC; and (4) diffusely infiltrated gland not related to (2) or (3). RESULTS In the subset of 27 patients, parotid nodal involvement was seen in 11 (41%) patients. Ten (37%) patients had cervical extranodal spread into the parotid gland. Three patients (11%) showed direct invasion by NPC, and another three patients (11%) showed an isolated and diffusely infiltrated parotid gland. CONCLUSION Metastatic NPC may involve parotid nodes. The parotid gland may also be involved by extracapsular spread from enlarged cervical nodes or infiltrated directly by the primary lesion in the nasopharynx.
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Abstract
The suprahyoid neck can be divided into fascia-bound spaces. These spaces, which are readily demonstrated on computed tomography (CT) and magnetic resonance imaging (MRI), form the anatomical framework for generating differential diagnosis and assessing disease extent. By correlating the radiological features with clinical information, the diagnostic possibilities of demonstrated lesions could be narrowed down considerably. Multiple space involvement is common in inflammatory and neoplastic processes and the full extent of these lesions should be outlined to facilitate surgical or radiotherapy planning.
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Goh YH, Chong VF, Low WK. Temporal bone tumours in patients irradiated for nasopharyngeal neoplasm. J Laryngol Otol 1999; 113:222-8. [PMID: 10435128 DOI: 10.1017/s0022215100143622] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Radiation-associated tumours are rare complications of radiotherapy. This study seeks to highlight and discuss the clinically challenging problem of radiation-associated tumours (RATs) in the temporal bones of seven patients previously irradiated for nasopharyngeal neoplasm. Seven patients (six males and one female) with radiation-associated temporal bone tumours are presented (five squamous cell carcinomas, one osteogenic sarcoma and one chondrosarcoma). The initial nasopharyngeal disease for which radiotherapy was indicated was nasopharyngeal carcinoma (six patients) and nasopharyngeal lymphoma (one patient). The latency period between radiotherapy and presentation of temporal bone tumours ranged from five years to 30 years with a mean of 12.9 years. All the patients underwent surgical tumour resection. Three patients had post-operative radiotherapy and one patient underwent pre- and post-operative chemotherapy. Two patients died from the disease within three months of treatment with one patient surviving 36 months at the time of writing. One patient died from an unrelated medical condition three months after surgery. With refinement in radiotherapy techniques and the resultant increase in patient survival, there may be more patients with radiation-associated tumours in the future. It remains imperative for clinicians to be vigilant when patients previously irradiated for nasopharyngeal carcinoma present with otological symptoms as the key to the successful management of this condition lies in the early detection and expedient treatment of this difficult disease.
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Abstract
The sphenoid bone is located in the central skull base and forms part of the floor of the anterior and middle cranial fossae. The optic foramen, superior orbital fissure, foramen rotundum, foramen ovale and foramen spinosum are found within this complex bone. These foramina form important transition zones between intracranial and extracranial structures. Imaging plays a central role in delineating lesions within the sphenoid bone and the associated fissures and neural foramina. The purpose of this pictorial review is to highlight the pertinent normal and pathological anatomy of the sphenoid bone.
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Abstract
Nasopharyngeal carcinoma (NPC) is an intriguing disease that shows a distinct geographical distribution with well-defined, high-risk ethnic groups. This neoplasm exhibits strong associations with the Epstein-Barr virus, dietary and genetic factors. Radiation therapy is the mainstay of treatment and imaging plays a central role in tumor mapping and radiation therapy planning. NPC provides an excellent model for the study of normal and pathological anatomy of the skull base. It also provides an excellent model in the study of consequences of radiation therapy.
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Chong VF, Fan YF, Khoo JB. Computed tomographic and magnetic resonance imaging findings in paranasal sinus involvement in nasopharyngeal carcinoma. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 1998; 27:800-4. [PMID: 10101553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Nasopharyngeal carcinoma (NPC) may spread to the paranasal sinuses. This retrospective study describes the features of paranasal sinus involvement in NPC on computed tomography (CT) and magnetic resonance imaging (MRI). One hundred and fourteen patients with histologically proven NPC underwent staging with both CT and MRI. Maxillary sinus infiltration was demonstrated on MRI in 10 patients; sphenoid sinus infiltration in 24 patients; and, ethmoid sinus involvement in 4 patients. CT could separate inflammatory changes from tumour in all maxillary sinuses but is less helpful in the sphenoid and ethmoid sinuses. Contrast-enhanced MRI could differentiate tumour from inflammatory changes in all sinuses. Using MRI as the standard, the rates of CT separating tumour from inflammation are: maxillary sinus (100%), sphenoid sinus (43%) and ethmoid sinus (25%). Histological confirmation of tumour involvement in the paranasal sinuses is not available. It is important to separate sinusitis from tumour infiltration as prognosis and treatment planning may be affected.
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Abstract
OBJECTIVE To correlate the features of inflammatory changes in the paranasal sinuses on magnetic resonance imaging (MRI) with computed tomography (CT). METHODS AND PATIENTS One hundred and fourteen patients with histologically proven nasopharyngeal carcinoma (NPC) were staged with both CT and MRI. All CT and MRI images of patients with mucosal thickening but no tumour involvement of the sinuses were retrospectively analysed. RESULTS There were inflammatory changes in 36 maxillary, 21 sphenoid and 16 ethmoid sinuses. These changes include mucosal thickening, retention cysts, retained secretions, inspissated secretions and dystrophic calcification. MRI is superior to CT in separating thickened mucosa, retained secretions and retentions cysts. CONCLUSION It is important to appreciate CT changes of sinusitis and the corresponding spectrum of MRI features.
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Chong VF, Fan YF, Lau D, Sethi DS. Functional endoscopic sinus surgery (FESS): what radiologists need to know. Clin Radiol 1998; 53:650-8. [PMID: 9766718 DOI: 10.1016/s0009-9260(98)80291-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The place of coronal computed tomography (CT) in the assessment of patients prior to functional endoscopic sinus surgery (FESS) is well established. The ability to accurately correlate radiological and surgical anatomy enhances precision and safety during FESS. This pictorial essay reviews the conceptual anatomical framework that forms the basis of FESS.
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Abstract
The parapharyngeal space (PPS) is a central space in the deep neck. Intrinsic lesions within this space are limited. Other spaces in the neck are closely related to the PPS and the direction of displacement of this space often suggests the origin of a lesion. The morphology of a lesion, together with the site of origin, helps in narrowing the diagnostic possibilities. The behaviour of the PPS often helps to determine whether a lesion is an intrinsic abnormality or whether it arises from a neighbouring space. Such information is crucial in the planning of surgical approach and the placement of drains.
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Abstract
The carotid space and the last four cranial nerves are at risk when nasopharyngeal carcinoma (NPC) recurs or spreads posterolaterally. The objective of this study is to document the features of hypoglossal nerve infiltration and the appearance of the paralysed tongue. We reviewed hypoglossal nerve palsy in 16 patients with NPC. The following features were analysed: tumour morphology (submucosal spread), hypoglossal canal erosion, perineural infiltration or intracranial spread, other lower cranial nerve palsies, and appearance of the tongue. These findings were correlated with clinical records. All 16 patients had tumour recurrence following radiation therapy. In 7 patients (44 %), recurrence was submucosal. Hypoglossal canal involvement was seen in 12 patients (75 %). Isolated hypoglossal nerve palsy was noted in 5 patients (31 %) and 7 patients (44 %) had posterior cranial fossa tumour spread. Posterior displacement of the tongue was consistently well seen. In conclusion, tumour recurrence should be suspected in the presence of hypoglossal nerve palsy even when endoscopic findings are negative. Posterior displacement of the tongue, which has not been emphasised in the literature, is an easily recognisable sign and may indicate early hypoglossal nerve palsy.
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Abstract
The jugular foramen, a complex bony canal, transmits vessels and nerves from the posterior cranial fossa through the skull base into the carotid space. It is inaccessible to clinical examination and radiology plays a central role in evaluating this region. Familiarity with the normal anatomy of this area will help in the formulation of differential diagnosis and the assessment of disease extent. Both intracranial and extracranial lesions may affect the jugular foramen in addition to intrinsic abnormalities. Normal variants and artefacts seen on magnetic resonance imaging (MRI) should not be mistaken for pathological processes.
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Abstract
The retropharyngeal space is a potential route for the spread of infection and malignancy. We present patients with squamous cell carcinoma of the larynx and tongue with superior contiguous spread along the retropharyngeal space resulting in skull base erosion. The fascia defining the retropharyngeal space is attached to the skull base and pathological processes can extend superiorly to destroy the skull base.
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Chong VF, Fan YF, Chan LL. Temporal lobe necrosis in nasopharyngeal carcinoma: pictorial essay. AUSTRALASIAN RADIOLOGY 1997; 41:392-7. [PMID: 9409038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Nasopharyngeal carcinoma (NPC) shows a high frequency of skull base erosion and intracranial spread. This tumour is usually treated with radiation therapy. The medial and inferior portions of both temporal lobes are included within the radiation portals. These areas are therefore potential sites of radiation-induced necrosis. It is important to recognize this complication and separate it from intracranial tumour recurrence because the treatments of these entities are different.
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Abstract
Spondylolisthesis with or without spondylolysis is common in the lumbar spine. Associated fracture in the pedicle ('pediculolysis') is unusual. The margins of pedicular stress fractures, like spondylolysis, usually appear sclerotic. A patient with a pedicular stress fracture with minimal marginal sclerosis suggesting an injury of recent onset is presented here. There was associated bilateral spondylolysis. The findings in this patient suggest that established pediculolysis probably represents a stress fracture that has failed to heal.
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Abstract
BACKGROUND Nasopharyngeal carcinoma (NPC) may infiltrate the pterygopalatine fossa (PPF) and the maxillary nerve. This study illustrates involvement of the maxillary nerve in the PPF with perineural spread to the cavernous sinus. METHODS One hundred and fourteen patients with proven NPC were studied using magnetic resonance imaging (MRI) and computed tomography (CT). The images were retrospectively reviewed for PPF infiltration and maxillary nerve involvement. RESULTS Seventeen (15%) patients showed infiltration of the PPF. Four patients had maxillary nerve involvement and a perineural spread to the cavernous sinus. Of the 17 patients with PPF infiltration, 8 (47%) patients showed hypoesthesia in the distribution of the infraorbital nerve. All 4 patients with contrast-enhancement of the maxillary nerve exhibited infraorbital neuropathy. CONCLUSION Infiltration of the maxillary nerve in the PPF with intracranial spread is uncommon but should be suspected in patients with infraorbital neuropathy. This is important as it affects both prognosis and radiation treatment planning.
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Chong VF. Amyloidosis of the thyroid. AJR Am J Roentgenol 1997; 168:845-6. [PMID: 9057552 DOI: 10.2214/ajr.168.3.9057552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Abstract
PURPOSE To compare the use of magnetic resonance (MR) imaging and computed tomography (CT) in detection of recurrent nasopharyngeal carcinoma. MATERIALS AND METHODS Forty-five sets of CT and MR images were obtained in 34 patients. The images were placed in three categories: (a) clinically or radiologically abnormal findings in patients who underwent biopsy (n = 16), (b) clinically normal and radiologically borderline findings in patients who were followed up clinically and radiologically (n = 10), and (c) clinically and radiologically normal findings in patients who were monitored only clinically (n = 19). All images were read by two observers independently. RESULTS There were nine positive and seven negative biopsy results. All patients in the latter two categories had normal findings at followup. CT had a sensitivity of 45% and 67% and a specificity of 64% and 70% for each of the two observers. MR imaging had a sensitivity of 56% (for both observers) and a specificity of 78% and 83%. The kappa test for interobserver concordance was 0.53 for CT and 0.66 for MR imaging. CONCLUSION Both modalities have relatively low sensitivity and moderate specificity in detection of tumor recurrence and in distinguishing recurrence from post-radiation therapy changes.
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