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The oral cavity is a complex anatomical region consisting of different anatomical sites and subsites. Cancer undoubtedly represents the most frequent and relevant disease of this region. Clinical examination is often the first approach to oral cavity tumours. Cross-sectional computed tomography (CT) and magnetic resonance imaging (MRI) play a key role in staging locoregional disease by demonstrating submucosal spread and involvement of deep layers; evaluation of specific pathways of spread to peculiar anatomical subsites is also fundamental information that can be obtained with these techniques. The purpose of this paper is to illustrate CT and MRI findings of anatomical subsites involved by tumours of the oral cavity.

Objective: The purpose of this study was to assess the value of dual-source dual-energy CT in the evaluation of complex cystic renal masses., Subjects and Methods: Seventy patients underwent contrast-enhanced dual-energy CT that included true unenhanced images acquired in single-energy mode, corticomedullary phase images acquired in dual-energy mode, and nephrographic phase images acquired in single-energy mode. Virtual unenhanced, blended weighted-average, and color-coded iodine overlay images were reconstructed. The acceptance level and image quality of virtual and true unenhanced images were evaluated. Contrast enhancement on both true unenhanced or blended weighted-average images and color-coded iodine overlay images was evaluated with both calculation in regions of interest and use of confidence level scales. Radiation dose parameters were estimated., Results: Virtual unenhanced images of 70 lesions (97.2%) and true unenhanced images of 72 lesions (100%) were judged acceptable (p = 0.5). The mean quality score of virtual unenhanced images was 2.0 ± 0.7 and of true unenhanced images was 1.5 ± 0.5 (p < 0.001). Mean contrast enhancement measured on true unenhanced and blended weighted-average images was 45.9 ± 15.9 HU (range, 21-78 HU) and on color-coded iodine overlay images was 47.3 ± 16.8 HU (range, 22-75 HU) with no significant differences. Enhancement was excluded on color-coded iodine overlay images with a significantly (p < 0.03) higher level of confidence than it was on true unenhanced and blended weighted-average images. The mean dose reduction with use of a combined dual- and single-energy dual-phase CT protocol was 29.1% ± 11.9% (p < 0.001)., Conclusion: Dual-source dual-energy CT is a reliable imaging technique in the evaluation of complex cystic renal masses. True unenhanced images can be replaced by virtual unenhanced images with considerable radiation dose reduction. The color-coded iodine overlay technique is a useful tool for both excluding and identifying endocystic enhancement.

Purpose: This study was undertaken to evaluate the potential of multidetector computed tomography (MDCT) for multiplanar visualisation of the tympanic canaliculus both in healthy individuals and in patients affected by chronic inflammatory disease of the middle ear., Materials and Methods: A preliminary study was performed on three dried skulls by placing a metal landmark inside the tympanic canal lumen with a view to optimising depiction by multiplanar CT. Subsequently, 50 patients were enrolled in a prospective study. Three of the 100 petrous pyramids studied were excluded owing to the presence of jugulotympanic glomus tumour with severe bone changes., Results: The entire course of the tympanic canaliculus was identified in 80/97 petrous pyramids (82.4%), 57 of which were normal (75.4% detection rate) and 40 pathological (90% detection rate). To assess the tympanic canaliculus in the pathological petrous pyramids and evaluate its possible role in the disease process, some qualitative criteria were introduced: canal enlargement, loss of margin sharpness, focal erosion of canal margins and presence of pathological tissue., Conclusions: MDCT represents the only technique allowing evaluation of the tympanic canal in vivo and with multiplanar images in a large number of cases (82.4%).

Objective: The purpose of our study was to evaluate the value of dual-source dual-energy CT with colored iodine overlay for detection of endoleaks after endovascular abdominal aortic aneurysm repair. We also calculated the potential dose reduction by using a dual-energy CT single-phase protocol., Subjects and Methods: From November 2007 to November 2009, 74 patients underwent CT angiography 2-7 days after endovascular repair during single-energy unenhanced and dual-energy venous phases. By using dual-energy software, the iodine overlay was superimposed on venous phase images with different percentages ranging between 0 (virtual unenhanced images) and 50-75% to show the iodine in an orange color. Two blinded readers evaluated the data for diagnosis of endoleaks during standard unenhanced and venous phase images (session 1, standard of reference) and virtual unenhanced and venous phase images with colored iodine overlay images (session 2). We compared the effective dose radiation of a single-energy biphasic protocol with that of a single-phase dual-energy protocol. The diagnostic accuracy of session 2 was calculated., Results: The mean dual-energy effective dose was 7.27 mSv. By using a dual-energy single-phase protocol, we obtained a mean dose reduction of 28% with respect to a single-energy biphasic protocol. The diagnostic accuracy of session 2 was: 100% sensitivity, 100% specificity, 100% negative predictive value, and 100% positive predictive value. Statistically significant differences in the level of confidence for endoleak detection between the two sessions were found by reviewers for scores 3-5., Conclusion: Dual-energy CT with colored iodine overlay is a useful diagnostic tool in endoleak detection. The use of a dual-energy single-phase study protocol will lower radiation exposure to patients.

Objective: The objective of our study was to assess a stone-targeted low-dose protocol for the detection and characterization of urinary tract stones using a dual-energy CT scanner., Subjects and Methods: Thirty-nine patients (20 men, 19 women; age range, 22-87 years; average age, 47 years) with suspected renal colic in which ureteral stones were shown at low-dose unenhanced CT were enrolled in the study. Stone composition could be established in 24 patients, and these patients represent our study population regarding the CT characterization of stones. All examinations were performed with a preliminary low-dose unenhanced CT acquisition of the whole urinary system that was immediately followed by a limited (scanning length, 5 cm) dual-energy acquisition of the region containing the ureteral stone. Stone characterization was assessed using a dual-energy software tool available on the system. Two experienced radiologists who were blinded to the chemical composition of the stones retrospectively reviewed images and analyzed data to determine the composition of the stones. Their results were compared with the biochemical analysis results obtained by stereomicroscopy and infrared spectrometry., Results: Based on in vitro-measured data, our combined protocol reduced dose by up to 50% compared with a full dual-energy acquisition; in addition, the calculated radiation doses of our protocol in patients are comparable to those of low-dose single- and dual-energy protocols. In 24 patients, 24 ureteral stones considered to be responsible for symptoms and detected at low-dose unenhanced CT were also shown at dual-energy CT. Correct chemical composition was obtained by dual-energy analysis in all 24 ureteral calculi regarding the characterization of uric acid (n = 3), calcium salt (n = 18), and combined uric acid-calcium salt (n = 3) stones., Conclusion: The use of dual-energy CT attenuation values made it possible to characterize all ureteral calculi, discriminating uric acid stones from calcium salt stones. The increment in radiation exposure due to contemporary scanning with two tubes at different energy levels can be substantially reduced using a limited stone-targeted dual-energy protocol.

Purpose: The purpose of this study was to demonstrate the usefulness of coronal oblique multiplanar reconstruction computed tomography (MPR CT) reformation parallel to the basal turn of the cochlea in the evaluation of the retrotympanum and hypotympanum to complete the standard CT examination of the temporal bone obtained with axial and coronal images., Materials and Methods: We studied 30 patients aged 18-79 years for a total of 60 normal petrous pyramids. All examinations were performed on a multislice CT (MSCT) scanner (Sensation 16, Siemens, Erlangen, Germany) with axial volumetric acquisition and completed with reformations of coronal and coronal-oblique images. MSCT scan parameters for axial acquisition were set as follows: 0.75-mm scan collimation, FOV 300 mm, 170 mAs. Axial images were reconstructed at 0.7-mm thickness and with a reconstruction increment of 0.5 mm using a high-resolution bone algorithm., Results: Coronal oblique MPR CT reformations provided additional information with respect to standard CT images in all cases. In particular, they enabled measurement of the craniocaudal and laterolateral diameters of the sinus tympani. In all cases, there was optimal visualisation of the ponticulus and subiculum. Analysis of the pyramidal eminence was improved thanks to its visualisation in profile. Moreover, we obtained an optimal representation of the hypotympanum, which was always exhaustively explored with only one reconstruction. Finally, in all cases, it was possible to identify the facial nerve canal and main vascular structures and to measure the distance between these and the sinus tympani, pyramidal eminence and hypotympanum. The coronal oblique CT reformation was of no advantage in the evaluation of the fossa of the oval window and the niche of the round window., Conclusions: Coronal oblique MPR CT reformation should not be considered an alternative to the standard CT examination, but it can represent a valid integration to provide additional information on particularly crucial districts characterised by frequent involvement of inflammatory and/or expansile disease and because of their difficult endoscopic approach. Moreover, it can represent a meaningful aid to optimise surgical planning thanks to its different perspectives of observation.

Diagnostic imaging plays an important role in both the planning of dental implants and the follow-up evaluation of the procedure. It is widely known that computed tomography (CT) together with Dentascan software is the most accurate imaging technique in the planning of implant treatment. Unlike conventional radiological techniques, CT enables the three-dimensional evaluation of the bone without the overlapping of adjacent structures, as well as a precise measurement of the bone tissue available in the future implant site, contributing in this way to a significant reduction in unsuccessful treatment. CT also enables a qualitative evaluation of the bone structure together with a precise definition of the adjacent anatomical structures and possible associated pathologies. Finally, given the wealth of information provided by CT, it is clear that the technique can also be used for judging in retrospect the correctness of a dental implant procedure. The present paper describes the CT findings that are most relevant to the medicolegal assessment of professional liability in implantology.

Endovascular repair of infrarenal abdominal aortic aneurysms is currently widely diffuse. Imaging plays a major role in the preprocedural patient evaluation, implantation of stent-graft, and patient follow-up. The aim of this paper is to describe the more frequent findings that can be seen in CT examinations after endovascular repair of infrarenal abdominal aortic aneurysm. We discuss CT findings related to the aneurysm (size, exclusion with complete perigraft thrombosis, back-filling of aneurysm sac via branch vessels) and to the device (dislocation, rotation, kinking, device expansion, patency/thrombosis, device disruption). We also show some examples of incorrect assembly of the modular components of the stent-graft.

We present a case of giant fibrovascular polyp of the esophagus with predominant fat contents. Both computed tomography (CT) and magnetic resonance imaging (MRI) findings of this rare tumor are reported. The employment of CT and MRI in the presurgical evaluation of fibrovascular esophageal polyp is suggested.

Recent advances in "functional" endoscopic surgical techniques require the radiologist to understand the anatomy and pathophysiology of the nose and paranasal sinuses as well as their normal and abnormal CT patterns. Endoscopy and CT are complementary procedures, but in the evaluation of the extent of chronic inflammation and in the demonstration of possible associated local and regional complications, the latter method has become the imaging technique of choice, providing a detailed map for the functional sinus surgeon and replacing plain radiography. The authors reviewed a personal series of 322 coronal thin-slice CT examinations of the paranasal sinuses relative to 169 patients with chronic or acute sinusitis and polyposis. The main CT findings of sinusitis (mucosal thickening, fluid retention, mucous cysts, bone alterations, mucoceles and polyposis) and their complications are reported. Finally, ostiomeatal conditions are considered, particularly the obstruction of ducts and ostia which provide aeration and mucous clearance from the paranasal sinuses.

This work was aimed at showing the main anatomical variations in the ostiomeatal complex which are usually depicted by CT. A hundred and thirty CT exams including 59 normal cases (45.4%) and 71 cases of chronic sinus disease (54.6%) were reviewed. The following anatomical variations were considered: concha bullosa, middle turbinate, septum, uncinate process and bulla changes, Haller cells and agger nasi cells. Anatomical variations were demonstrated in 69 patients--31 normal subjects and 38 patients with chronic sinusitis. The incidence of every anatomical variation was investigated and the results were compared with literature data. Excluding agger nasi cells, which were seen in nearly all patients, the most common variations were concha bullosa and septal spur and deviations, while the least common variations were those in the middle turbinate and uncinate process.

Computed tomographic findings are reviewed in 25 patients with a palpable mass in the anterior abdominal wall. Computed tomography allowed a specific diagnosis when the mass was due to a hernia and hematoma. In the other cases a specific diagnosis could not be made but CT allowed a detailed evaluation of the extent of the disease.

The parapharyngeal space is a fat-filled region situated deep in the head between the basicranium and the oral floor. It can be divided in two parts: the prestyloid and the poststyloid space. The mandibular nerve is contained in the prestyloid space, while the carotid artery, jugular vein, IX, X, XI, XII cranial nerves, cervical sympathetic chain and junctional lymph nodes are situated in the poststyloid compartment. The normal CT anatomy and CT findings in 22 patients with proven lesions of the parapharyngeal space are described. Three different groups of neoplastic processes can be distinguished: primary tumours, secondary tumours and enlarged lymph nodes. The nature of the lesions developing in the parapharyngeal space can be diagnosed by CT in many cases.

We describe the computed tomographic findings in two cases of bilateral hydronephrosis due to hydatid cyst located in the pouch of Douglas. In both cases this location was secondary to the spontaneous rupture of an hepatic cyst.

The CT findings in 24 patients with clinically evident carcinomatous neuropathy from pelvic soft tissue involvement are described. Computed tomography is mandatory to differentiate carcinomatous pelvic neuropathy from other causes of pelvic neuropathy as well as to plan radiation treatment.