Direct Coronal Scanning Research Articles

Prevalence of normal anatomical variations in the region of paranasal sinuses in patients with chronic rhinosinusitis

Background: Knowledge of the anatomical relationships and the anatomical variations in paranasal sinus region is critical for surgeons performing endoscopic sinus surgery. It helps surgeons to avoid the potential complications of sinus surgery and to improve success of management strategies. Objective: The objective of this study was to show how prevalent are the anatomic variations in the region of the paranasal sinuses and nasal cavity in patients with chronic rhinosinusitis. Materials and Methods: A cross-sectional study was conducted from January 2018 to July 2018 at Al-Hilla general teaching hospital. We collected data of 75 patients (who have met the clinical criteria of chronic rhinosinusitis) subjected to computed tomography (CT) of the paranasal sinuses. CT was performed using SIEMENS SOMATOM Definition AS and Philips machines. Direct coronal scans (1 mm in thickness) were made, from the anterior wall of the frontal sinus to the posterior wall of the sphenoid sinus with axial and sagittal reconstruction images. Results: Anatomical variations found in 69 patients of a total 75 patients with age range from 18 to 60 years with 92%. Among these, nasal septal deviation was the most common (seen in 54/75 patients = 72%) followed by the Agger nasi cells in 52 patients (69%), concha bullosa in 31 patients (41.3%), Haller cells in 28 patients (37%), and Onodi cells in 18 patients (24%). Conclusion: Sinonasal anatomical variations are common findings in patients with chronic rhinosinusitis. Providing information on these anatomical variations will improve the success of endoscopic sinus surgery.

Radiation dose to the lens of eye and thyroid gland in paranasal sinus multislice CT.

CT has become an established examination in the evaluation of the paranasal sinuses. Until recently this was achieved by the direct coronal technique on conventional and single slice helical scanners. With the advent of multislice technology, thin slice axial CT with excellent coronal and sagittal reconstructions is now the norm. We describe a study designed to evaluate the radiation dose to the lens of the eye and thyroid gland in the axial and coronal planes on a Siemens Volume Zoom quad slice scanner at 140 kV and effective mAs of 100 using 1 mm collimation. Thermoluminescent dosimeters were placed on the eyelid and thyroid gland of 29 patients scanned axially in the supine position and a further 28 patients scanned coronally in the prone position with gantry tilt. The results show mean doses of 35.1 mGy (lens) and 2.9 mGy (thyroid gland) in the coronal plane compared with 24.5 mGy (lens) and 1.4 mGy (thyroid gland) in the axial plane. Results obtained from a head phantom and from using the ImPACT CT dose calculator were comparable. The kV and mAs were then reduced to 120 and 40, respectively, and the axial study repeated using the head phantom and predicted doses using the ImPACT CT dose calculator. The low dose scanning technique revealed a lens dose of 9.2 mGy and thyroid dose of 0.4 mGy. The eye dose on a multislice scanner is still substantially less than the threshold dose of 0.5-2 Gy for detectable lens opacities. These results indicate that, in addition to the established perceived advantages of multislice axial sinus CT, i.e. patient comfort, no artefact from dental amalgam and reproducible true coronal images, should be included a decreased radiation dose to both the eye lens and thyroid gland compared with direct coronal scanning.

Multiplanar imaging in the preoperative assessment of metallic intraocular foreign bodies: Helical computed tomography versus conventional computed tomography

Objective This study aimed to compare the effectiveness of helical computed tomography (CT) versus conventional CT in the preoperative assessment of metallic intraocular foreign bodies on axial, coronal, and multiplanar reconstruction images in clinical routine. Design Prospective comparative trial, alternate assignment of consecutive patients. Participants Eighteen patients with penetrating eye injuries and suspected metallic intraocular foreign bodies were studied. Intervention Alternate patients were assigned to undergo either helical CT or conventional CT in the axial plane. Both the helical and the conventional data were transferred to a workstation, and reconstructions in the coronal and sagittal planes were performed. Additional direct coronal scanning was performed only when necessary for preoperative assessment. Main outcome measures The quality of the directly obtained axial and coronal, as well as the reconstructed coronal and sagittal images, was assessed for each imaging method based on the ability to detect and accurately localize foreign bodies. The size of the foreign bodies was measured and compared to the actual diameter. Total examination time and radiation dose delivered to the lens were measured for each imaging method. Results All foreign bodies were detected by each scanning method on the axial, the coronal, and on the reconstructed planes. The quality of the axial images was similar for helical and conventional CT. The helical technique provided high-quality reconstructed images comparable in quality to the directly obtained coronal planes in conventional CT. Reconstructions by conventional technique were not useful for preoperative assessment. The examination time for the total orbital volume was 18 seconds for helical CT examinations and 52 seconds for conventional CT examinations. Radiation dose delivered to the lens for the complete examination was 35 mGy for helical CT axial scanning, 56 mGy for conventional CT axial scanning, and 63 mGy for conventional CT coronal scanning. Conclusions Helical CT multiplanar imaging offers several significant advantages for the preoperative assessment of metallic intraocular foreign bodies compared to the conventional CT technique in clinical practice, including short examination time, reduced motion artifacts, reduced radiation exposure, and the ability to obtain diagnostically useful coronal and sagittal reconstruction images without the need for additional scanning.

Piriform Aperture Stenosis

Because neonates are obligate nasal breathers, neonatal nasal obstruction may have serious consequences. Prompt diagnosis and appropriate treatment are essential to avoid severe hypoxia. Anterior inlet, piriform aperture stenosis is an extremely rare cause of neonatal nasal airway obstruction and can easily be confused with choanal atresia or stenosis. Computed tomography with direct coronal scans is the best means of establishing a definitive diagnosis. We present our experience with four neonates having nearly complete piriform aperture stenosis. Prompt surgical enlargement of the nasal inlet through an upper buccal sulcus approach is recommended.

CT evaluation of tracheobronchial tumors in children

Computed tomography (CT) of the chest is a reliable method for the evaluation of lesions which may involve the mediastinum, tracheobronchial tree, pulmonary parenchyma and chest wall. The addition of the direct coronal scanning to routine axial sectioning can result in better demonstration of endobronchial tumors. We describe imaging of the bronchi in 6 pediatric patients with rare tracheobronchial tumors.

眼か下壁骨折（Ｂｌｏｗ‐ｏｕｔ ｆｒａｃｔｕｒｅ）のＣＴ診断 ＣＴ２方向撮影による評価

Diagnosis of a blow-out fracture of the orbital floor is relatively easy from clinical and roentogen findings but information from these findings are not adequate for the decision for surgical indication.Until recently, computed tomography for the orbital region was generally performed only in axial plane. But the axial plane is parallel to the orbital structure, therefore it is difficult to visualize the orbital floor and inferior rectus muscle. On the other hand, coronal plane is cross-section to the orbital structure, and we can visualize the all orbital soft tissues including extraocular muscles.We examined 3 cases diagnosed as a blow-out fracture of the orbital floor by conventional roentogen films and clinical findings. After axial CT was performed firstly, the coronal CT was scanned with 60 degrees to 70 degrees from OM line, setting the patient in the hanging head position.Case 1 used coronal reformation of the axial CT data. Case 2 and case 3 used direct coronal scanning. By bi-plane CT we could diagnose whether inferior rectus muscle was entrapped or not, and confirm surgical indication.Using of a cadaver, we studied the mechanism for limitation of eye movement. These studies revealed that it is rare that the inferior rectus muscle is entrapped directly by fractured segments at the orbital anterior floor. Because there is a lot of orbital fat-pad between the inferior rectus muscle and the orbital floor, and it may play an important role.The limited mobility of the inferior rectus muscle may occur as a result of increased tension of the fibrous bands that attach to the muscle sheath from the prolapsed fat-pad, and contructure by scar formed secondarily.Diagnosis of the location of a fracture in the orbital floor and cause of the limitation of eye movement must be done as early as possible and from this information we can confirm surgical indiction. We believe the bi-plane CT is one of the most useful methods for making a management plan of blow-out fractures of the orbital floor.

CT-guided percutaneous bowel loopogram.

CT-guided percutaneous bowel loopogramWK Hoddick, BE Demas and AA MossAudio Available | Share