Tongue cancer CT
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [3]
Overview
Head and neck CT scan may be helpful in the diagnosis of tongue cancer. Findings on CT scan suggestive of tongue cancer include soft tissue attenuation of lesions, bony erosions, and increased attenuation of involved nodes.[1]
CT
- CT is the most commonly used modality for assessment of tongue squamous cell carcinoma
- Lesions typically appear more attenuating than normal tongue musculature (on account of the keratin) and enhance following contrast administration.
- Non-contrast scans of the neck may demonstrate increased attenuation of involved nodes due to keratin production by tumor deposits.[1]
- CT is better for the evaluation of bone destruction.
- Assessment of cartilage invasion.[2]
- Detection of extracapsular spread of tumor.
- Pathologic lymph nodes are 10 to 11 mm and contains central necrosis. Size criteria based on measurement of minimal axial diameter are considered the most accurate and effective.[3]
- Pathological lymph nodes show: loss of normal fatty hilum, increased or heterogeneous contrast enhancement, lymph node clustering.[4]
- Sensitivity is 83% and specificity is 83%.[5]
PET-CT scan
Injection of positron-emitting radionuclides, such as fluorine-18, are taken up by metabolically or functionally active tissues. PET images are created by detecting these emissions by an array of detectors and then using reconstruction techniques to create a three dimensional image. The most commonly used agent is fluorodeoxyglucose (FDG), which is taken up into cells in different concentrations depending on the relative metabolism of different tissues. It is fairly specific for tumors because metabolic rates are very high in many tumors.
Imaging of the primary tumor site and regional lymph nodes with PET is limited by its poor spatial resolution, which can make it difficult to localize the anatomic location of the FDG uptake. These issues can be at least partially addressed with integrated PET/CT imaging, in which PET and CT are performed sequentially during a single visit on a hybrid PET/CT scanner. The images are then coregistered using fusion software, enabling the physiologic data obtained on PET to be localized according to the anatomic CT images.
Historically, CT images obtained from integrated PET/CT scanners had lower spatial resolution compared with dedicated CT scanners. This problem is now being overcome by new generation of PET/CT scanners that offer volumetric CT capability
PET appears to be at least as sensitive and specific as CT and MRI in detecting primary head and neck tumors [41-44]. More importantly, PET is superior to both CT and MRI for detecting regional nodal metastases, as well as distant metastases and second primary tumors [45-47].
Despite these data, the value of PET is uncertain for patients with a clinically negative (N0) neck, a reflection of its limitations in detecting occult nodal metastases less than 5 mm. The sensitivity of PET is lower in this setting (25 to 51 percent in four separate studies [48-51]), although at least one series reports better results [52]. Some of this disparity may be due to the detail with which resected lymph nodes are examined pathologically [53].
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CT of squamous cell carcinoma of the tongue showing axial bone window [6]
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CT of squamous cell carcinoma of the tongue showing coronal bone window[6]
References
- ↑ 1.0 1.1 Sqamous cell carcinoma of the tongue. Radiopedia(2015) http://radiopaedia.org/articles/squamous-cell-carcinoma-of-the-tongue Accessed on November 17, 2015
- ↑ Kuno H, Onaya H, Iwata R, Kobayashi T, Fujii S, Hayashi R; et al. (2012). "Evaluation of cartilage invasion by laryngeal and hypopharyngeal squamous cell carcinoma with dual-energy CT". Radiology. 265 (2): 488–96. doi:10.1148/radiol.12111719. PMID 22984188.
- ↑ van den Brekel MW, Stel HV, Castelijns JA, Nauta JJ, van der Waal I, Valk J; et al. (1990). "Cervical lymph node metastasis: assessment of radiologic criteria". Radiology. 177 (2): 379–84. doi:10.1148/radiology.177.2.2217772. PMID 2217772.
- ↑ Curtin HD, Ishwaran H, Mancuso AA, Dalley RW, Caudry DJ, McNeil BJ (1998). "Comparison of CT and MR imaging in staging of neck metastases". Radiology. 207 (1): 123–30. doi:10.1148/radiology.207.1.9530307. PMID 9530307.
- ↑ Merritt RM, Williams MF, James TH, Porubsky ES (1997). "Detection of cervical metastasis. A meta-analysis comparing computed tomography with physical examination". Arch Otolaryngol Head Neck Surg. 123 (2): 149–52. PMID 9046281.
- ↑ 6.0 6.1 Image courtesy of Dr. Bruno Di Muzio Radiopaedia (original file [1]).[http://radiopaedia.org/licence Creative Commons BY-SA-NC