Similar to standard multidetector CT, CBCT can confirm the diagnosis of CRS and identify anatomic variants for presurgical planning. One study showed decreased detection of intrasinus calcifications in patients with noninvasive fungal sinusitis compared with multidetector CT, although comparison between the 2 modalities was done in separate patient cohorts [34]. CBCT is limited in the evaluation of soft-tissue structures and therefore is not the imaging modality of choice if extrasinus disease is suspected [19,25]. CT Head Given its typical incomplete coverage of the paranasal sinuses, CT head is not typically performed for the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. CT Maxillofacial Given its excellent bony detail, multidetector CT without IV contrast is useful for confirming and evaluating CRS and for presurgical planning. Imaging findings that confirm CRS include mucosal thickening, sinus opacification, polyps or retention cysts, and sclerosis and thickening of the sinus walls [2,26]. CT has been shown to accurately identify these findings of CRS, although the findings have been shown to not necessarily correlate with the severity of symptoms [26]. CT can also evaluate the extent of disease and identify anatomic variants that narrow sinus drainage pathways [32]. CT is critical for surgical planning, in particular for the identification of anatomic variants and abnormalities that can increase the risk for intracranial, intraorbital, and vascular injury as well as for CSF leak [31,32]. Low-dose techniques have been shown to be limited in the visualization of surgically relevant anatomical structures including the cribriform plates, lamina papyracea, and anterior ethmoidal artery canal in the setting of CRS with nasal polyps and a history of sinus surgery [35]. A sinus CT protocol that can be utilized by image guidance systems is recommended [36].
Sinonasal Disease. Similar to standard multidetector CT, CBCT can confirm the diagnosis of CRS and identify anatomic variants for presurgical planning. One study showed decreased detection of intrasinus calcifications in patients with noninvasive fungal sinusitis compared with multidetector CT, although comparison between the 2 modalities was done in separate patient cohorts [34]. CBCT is limited in the evaluation of soft-tissue structures and therefore is not the imaging modality of choice if extrasinus disease is suspected [19,25]. CT Head Given its typical incomplete coverage of the paranasal sinuses, CT head is not typically performed for the evaluation of CRS or for presurgical planning of paranasal sinus inflammatory disease. CT Maxillofacial Given its excellent bony detail, multidetector CT without IV contrast is useful for confirming and evaluating CRS and for presurgical planning. Imaging findings that confirm CRS include mucosal thickening, sinus opacification, polyps or retention cysts, and sclerosis and thickening of the sinus walls [2,26]. CT has been shown to accurately identify these findings of CRS, although the findings have been shown to not necessarily correlate with the severity of symptoms [26]. CT can also evaluate the extent of disease and identify anatomic variants that narrow sinus drainage pathways [32]. CT is critical for surgical planning, in particular for the identification of anatomic variants and abnormalities that can increase the risk for intracranial, intraorbital, and vascular injury as well as for CSF leak [31,32]. Low-dose techniques have been shown to be limited in the visualization of surgically relevant anatomical structures including the cribriform plates, lamina papyracea, and anterior ethmoidal artery canal in the setting of CRS with nasal polyps and a history of sinus surgery [35]. A sinus CT protocol that can be utilized by image guidance systems is recommended [36].