Sémiologie de l'atteinte bronchique en scanner [Bronchial diseases: CT imaging features].

Multidetector row computed tomography (MDCT) is the imaging modality of reference for the diagnosis of bronchiectasis. MDCT may also detect a focal stenosis, a tumor or multiple morphologic abnormalities of the bronchial tree. It may orient the endoscopist towards the abnormal bronchi, and in all cases assess the extent of the bronchial lesions. The CT findings of bronchial abnormalities include anomalies of bronchial division and origin, bronchial stenosis, bronchial wall thickening, lumen dilatation, and mucoid impaction. The main CT features of bronchiectasis are increased bronchoarterial ratio, lack of bronchial tapering, and visibility of peripheral airways. Other bronchial abnormalities include excessive bronchial collapse at expiration, outpouchings and diverticula, dehiscence, fistulas, and calcifications.

Robotic, fluoroscopic or EMG assisted pedicle screw insertion. A CT based comparative study

Introduction: In order to improve safety of pedicle screw placement several techniques have been developed. More recently robotically assisted pedicle insertion has been introduced aiming at increasing accuracy. The aim of this study was to compare this new technique with the two main pedicle insertion techniques in our unit namely fluoroscopically assisted vs EMG aided insertion. Material and methods: A total of 382 screws (78 thoracic,304 lumbar) were introduced in 64 patients (m/f = 1.37, equally distributed between insertion technique groups) by a single experienced spinal surgeon. From those, 64 (10 thoracic, 54 lumbar) were introduced in 11 patients using a miniature robotic device based on pre operative CT images under fluoroscopic control. 142 (4 thoracic, 138 lumbar) screws were introduced using lateral fluoroscopy in 27 patients while 176 (64 thoracic, 112 lumbar) screws in 26 patients were inserted using both fluoroscopy and EMG monitoring. There was no difference in the distribution of scoliotic spines between the 3 groups (n = 13). Screw position was assessed by an independent observer on CTs in axial, sagittal and coronal planes using the Rampersaud A to D classification. Data of lumbar and thoracic screws were processed separately as well as data obtained from axial, sagittal and coronal CT planes. Results: Intra- and interobserver reliability of the Rampersaud classification was moderate, (0.35 and 0.45 respectively) being the least good on axial plane. The total number of misplaced screws (C&D grades) was generally low (12 thoracic and 12 lumbar screws). Misplacement rates were same in straight and scoliotic spines. The only difference in misplacement rates was observed on axial and coronal images in the EMG assisted thoracic screw group with a higher proportion of C or D grades (p <0.05) in that group. Recorded compound muscle action potentials (CMAP) values of the inserted screws were 30.4 mA for the robot and 24.9mA for the freehand technique with a CI of 3.8 of the mean difference of 5.5 mA. Discussion: Robotic placement did improve the placement of thoracic screws but not that of lumbar screws possibly because our misplacement rates in general near that of published navigation series. Robotically assisted spine surgery might therefore enhance the safety of screw placement in particular in training settings were different users at various stages of their learning curve are involved in pedicle instrumentation.

New Horizons in Forensic Imaging: Post Mortem CT Angiography - Benefits and Practical Application.

Puropse/Aim: To learn about the developement of post mortem CT angiography, its indications, benefits, pitfalls and practical application. Content Organization: A. Developement of post mortem CT angiography B. Technical prerequisites C. Practical application of post mortem CT angiography (preparation of the body, injection of contrast agent, examination protocol) D. Indications and benefits (including a comparison with conventional autopsy) E. Interpretation of imaging data (with case demonstrations) F. Artifacts, pitfalls and limitations G. Current and potential future use. Summary: This exhibit demonstrates the developement, application and interpretation of post mortem CT angiography. Teaching points: 1. post mortem CT angiography is feasible and useful for identification of the cause of death 2. depending on the indication it can be superior to autopsy 3. limitations and artifacts need to be known for interpreta

Three-dimensional cholangio-spiral CT demonstration of a post-traumatic bile leak in a child.

Bilioma is a rare complication of traumatic liver injury, and the precise site of bile leak is often difficult to demonstrate with a non-invasive technique. We report a case of post-traumatic bile leak in a 15-year-old girl in whom spiral CT after intravenous cholangiography allowed excellent preoperative demonstration of the extent of the liver rupture and an exact location of the bile leak. We think that spiral-CT cholangiography could be an accurate, non-invasive technique to investigate the biliary system in cases of paediatric liver trauma.

Ruptured pseudo-aneurysm of a femoral artery in a drug abuser revealed by post-mortem CT angiography.

A 35-year-old drug addict was found dead in a public toilet with a ruptured groin, which was later diagnosed to be a leaking pseudo-aneurysm. Investigation at the scene revealed impressive external hemorrhage related to a groin wound. Post-mortem computed tomography angiography demonstrated an aneurysm of the right femoral artery with leak of contrast liquid. Signs of blood loss were evident at autopsy, and histological examination revealed necrosis and rupture of the pseudo-aneurysm. Toxicological analyses were positive for methadone, cocaine, citalopram, and benzodiazepines. This is the first case report in the literature of a ruptured femoral pseudo-aneurysm with a post-mortem radiological diagnosis.

Neuroimaging techniques in Alzheimer's disease

Neuroimaging techniques provide valuable tools for diagnosing Alzheimer's disease (AD), monitoring disease progression and evaluating responses to treatment. There is currently a wide array of techniques available including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and, for recording electrical brain activity, electroencephalography (EEG). The choice of technique depends on the contrast between tissues of interest, spatial resolution, temporal resolution, requirements for functional data and the probable number of scans required. For example, while PET, CT and MRI can be used to differentiate between AD and other dementias, MRI is safer and provides better contrast of soft tissues. Neuroimaging is a technique spanning many disciplines and requires effective communication between doctors requesting a scan of a patient or group of patients and those with technical expertise. Consideration and discussion of the most suitable type of scan and the necessary settings to achieve the best results will help ensure appropriate techniques are chosen and used effectively. Neuroimaging techniques are currently expanding understanding of the structural and functional changes that occur in dementia. Further research may allow identification of early neurological signs ofAD, before clinical symptoms are evident, providing the opportunity to test preventative therapies. CombiningMRI and machine learning techniques may be a powerful approach to improve diagnosis ofAD and to predict clinical outcomes.

Extent of Hypoattenuation On CT Angiography Source Images In Basilar Artery Occlusion: Prognostic Accuracy Of Posterior Circulation ASPECTS And The Pons-midbrain Score In The Basilar Artery International Cooperation Study

Background: The posterior circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) and the combined Pons-midbrain score quantify the extent of early ischemic changes in the posterior circulation. We compared the prognostic accuracy of both scores if applied to CT angiography (CTA) source images (CTA-SI) of patients in the Basilar Artery International Cooperation Study (BASICS).Methods: BASICS was a prospective, observational, multi-centre, registry of consecutive patients who presented with acute symptomatic basilar artery occlusion (BAO). Functional outcome was assessed at 1 month. We applied pc-ASPECTS and the combined Pons-midbrain score to CTA-SI by 3-reader-consensus. Readers were blinded to clinical data. We performed multivariable logistic regression analysis, adjusting for thrombolysis, baseline NIHSS score and age, and used the output to derive ROC curves to compare the ability of both scores to discriminate patients with favourable (modified Rankin Scale [mRS] scores 0-3) from patients with unfavourable (mRS scores 4-6) functional outcome.Results: We reviewed CTAs of 158 patients (64% men, mean age 65 _ 15 years, median NIHSS score 25 [0-38], median GCS score 7 [3-15], median onset-to-CTA time 234 minutes [11-7380]). At 1 month, 40 (25%) patients had a favourable outcome, 49 (31%) had an unfavourable outcome (mRS score 4-5) and 69 (44%) were deceased. Both techniques of assessing CTA-SI hypoattenuation in the posterior circulation showed equally good discriminative value in predicting final outcome (C-statistics; area under ROC curve 0.74 versus 0.75, respectively; p_0.37). Pc-ASPECTS dichotomized at _6 versus _6 was an independent predictor of favourable functional outcome (RR _ 2.2; CI95 1.1-4.7; p _ 0.034).Conclusion: Compared to the combined Pons-midbrain score, the pc-ASPECTS score has similar prognostic accuracy to identify patients with a favourable functional outcome in BASICS. Dichotomized pc-ASPECTS (_6 versus _6) is an independent predictor of favourable functional outcome in this population. Author Disclosures: V. Puetz: None. A. Khomenko: None. M.D. Hill: None. I. Dzialowski: None. P. Michel: None. C. Weimar: None. C.A.C. Wijman: None. H. Mattle: None. K. Muir: None. T. Pfefferkorn: None. D. Tanne: None. S. Engelter: None. K. Szabo: None. A. Algra: None. A.M. Demchuk: None. W.J. Schonewille: None.

Volumetric quantification of atherosclerotic plaque in CT considering partial volume effect.

Coronary artery calcification (CAC) is quantified based on a computed tomography (CT) scan image. A calcified region is identified. Modified expectation maximization (MEM) of a statistical model for the calcified and background material is used to estimate the partial calcium content of the voxels. The algorithm limits the region over which MEM is performed. By using MEM, the statistical properties of the model are iteratively updated based on the calculated resultant calcium distribution from the previous iteration. The estimated statistical properties are used to generate a map of the partial calcium content in the calcified region. The volume of calcium in the calcified region is determined based on the map. The experimental results on a cardiac phantom, scanned 90 times using 15 different protocols, demonstrate that the proposed method is less sensitive to partial volume effect and noise, with average error of 9.5% (standard deviation (SD) of 5-7mm(3)) compared with 67% (SD of 3-20mm(3)) for conventional techniques. The high reproducibility of the proposed method for 35 patients, scanned twice using the same protocol at a minimum interval of 10 min, shows that the method provides 2-3 times lower interscan variation than conventional techniques.

Solitary fibrous tumor of the lateral ventricle: CT appearances and pathologic correlation with follow-up.

Intracranial solitary fibrous tumors are rare, and intraventricular fibrous tumors are even more unusual. We report a case of solitary fibrous tumor in the region of trigone and body of the left lateral ventricle and discuss the clinical presentation, CT characteristics, and histopathologic features with 1-year follow-up. We speculate that the tumor arose from the perivascular connective tissue of the choroid plexus.