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Abstract
Summary and Conclusion Nasopharyngeal space is a closed space and is surrounded by many important structures , lesions of nasopharynx show difficult in of diagnose their nature and extent to related spaces of the nasopharynx. All these lesions should therefore be assessed when examining nasopharyngeal. So computed tomography and magnetic resonance imaging are needed to detect the nature of these lesions and there relations and extent to other neck structures and possible skull base involvement.The aim of this study was to diagnose various nasopharyngeal lesions and to compare the efficiency of both CT and MRI in diagnoses of these lesions.This study was performed on ٥٤ patients with age between ٣y up to ٨٠y old attending the ENT and oncology departments in outpatient clinics in Minofiya University from January ٢٠٠٨ till January ٢٠١٠ were referred to radiology department for detection of any nasopharyngeal masses .All patients were subjected to history recording and full clinical examination . Patients consent was taken for radiological examination .histopathology of the nasopharyngeal masses was done for ٥٠ patients. Nasal endoscopy was done in ٤٥ cases. Nature and extent of the masses were seen and staging was done accordingly. Summary and conclusion ١٢٦ All cases were analyzed on CT scans in axial views, and ١٠ cases in coronal views for regional involvement of the nasopharyngeal soft tissues and skull base. scanning was performed on different CT machines Fourty-six cases needed to be confirmed by MRI. Which was performed in T١ and T٢ axial , saggital and coronal views and in T١ with contrast Ten patients needed sedation during examination on CT and general anaesthesia in MRI and complications in the form of minor hypersensitivity reaction was seen in ٦ patients ,no major complications from contrast was seen. Data was analyzed depending on several CT and MRI findings as follow : In CT scanning for all patients we looked for : ١- Site of the lesion ٢- Size of the lesion ٣- Type of the lesion (cystic or solid ) ٤- Enhancement after contrast injection [not enhanced, moderate enhancement (density increased by less than ١٥ HU) &marked enhancement (density increased by more than ١٥ HU)]. ٥- Invasion of surrounding tissue ٦- Bone destruction with widening of fissures and foramina ٧- Skull base and brain invasion ٨- Regional lymph nodes enlargement In MRI scanning for all examined patients we looked for: ١- Site of the lesion Summary and conclusion ١٢٧ ٢- Intensity of the lesion in T١ and T٢ in comparison to the related
muscles : Intensity less than muscle ….low As muscle …………………...iso Slightly higher than muscles... Slightly high Higher than muscles ………..high ٣- Enhancement after contrast injection ٤- Bone marrow invasion ٥- Soft tissue invasion ٦- Skull base and brain invasion In this study we found that dominant age group was above ٤٠ years and malignant lesions presented ٦٣٪of cases. also this study showed that ٩٪ of cases where diagnosed as antrochoanal polyp .٩٪ as Angiofibroma .٥٫٥٪ as prominent adenoid and ٤٢٪ as nasopharyngeal carcinoma. In this study nasopharyngeal carcinoma showed that intensity in both T١ and T٢ is slightly high than related muscles (٨٠ % and ٧١٪). lymph nodes with nasopharyngeal carcinoma were seen in (٨٦ %) of cases. bone invasion was seen in ٦٦٫٧٪ of cases , extension in CT was seen in ٥٢٫٤٪ of cases and in MRI in ٦٦٫٧ %. In this study CT was inferior to MRI in detection of tumor extension ٥٢٫٤٪ in CT compared to ٦٦٫٧ % in MRI. In this study TNM staging of nasopharyngeal carcinoma was different when comparing CT with MRI and with final diagnosis .stage I in CT represented ٢٣٪ of cases while in MRI only ٨٪ ,stage II Summary and conclusion ١٢٨ represented ٢٧٪ of CT diagnosis and ٢٢٪ of MRI diagnosis . On the reverse stage III and stage IV where higher in MRI than in CT. Lymphoma showed lymph nodes in ٩٠٪ of cases , moderate enhancement in CT (١٠٠٪) and in MRI (٨٠٪) , also lymphoma showed (٨٠٪)isointens in T١ and (١٠٠٪) hyperintens in T٢ ,however skull base invasion was seen only in ٣٠٪ of cases in CT and ٥٠ % skull base invasion in MRI .In this study JNA showed marked enhancement in CT (٨٠٪) with skull base invasion in (١٠٠٪) of cases and extension to the skull base (٢٠٪) of cases on both CT and MRI. Also JNA was isointens in T١ and hyperintens in T٢ with areas of signal void. In this study accuracy of CT for inflammatory lesions was (٩٨٪) , for benign lesions was ٩٦٪ , for malignant lesions was ٨٦٫٣ % and for extrinsic lesions was ١٠٠٪ . this values increased in MRI for malignant lesions as it was ٩٦٪ .however this was not highly significant as P value was<٠٫٠٥ .from this study we concluded that : ١- The place of CT in the evaluation of nasopharyngeal masses is now extensively documented.٢- CT is of short period of examination , less irritant to patients , need less preparations and it is less expensive than MRI. also CT in paediatric age group is easier to perform than MRI as patients needed sedation only while on MRI patients needed general anaesthesia Summary and conclusion ١٢٩ ٣- CT remains the most commonly used modality for diagnosis and staging in regions where NPC occur with high frequencies, as access to MRI is still limited. ٤- MRI is superior to CT in demonstrating the tumor soft tissue extent. It was generally accepted that CT was superior to MRI in detecting skull base involvement. It is now known that MRI is more sensitive to CT in detecting skull base marrow changes with change of staging according to this .٥- Conventional radiographs and CT also have substantial value in patients with suspected bone metastases, and both procedures can supplement radionuclide imaging in defining the precise location and topography of the lesions. ٦-Although MRI is more sensitive to CT in detecting marrow changes, the specificity of this observation remains unknown. This is because, in patients with squamous cell carcinoma, histopathologic verification of skull base lesions cannot be easily performed. The nasopharynx ٦-MRI is far more sensitive than CT in detecting perineural tumor spread. It is clear that MRI may upstage many tumors staged with CT. This may introduce potential problems when comparing the results of treatment outcome. ٧- Cervical lymphadenopathy is better studied with CT especially for nodal necrosis and extracapsular spread. ٨- It is uncommon for CT to provide additional information over MRI resulting in a change of treatment strategy. According to these conclusions recommendations for diagnosis of nasopharyngeal masses are as follow : Summary and conclusion ١٣٠ ١- good clinical history and careful examination of the patients will is needed before any investigations .٢- according to clinical data investigations will be determined plain X-ray film my be the only investigations needed in case of adenoids or retropharyngeal abscess .٣- whenever more investigations needed CT is used and if diagnoses is controversy specially in diagnosis of staging of nasopharyngeal carcinoma MRI will be performed .