[Preoperative assessment of renal vascular anatomy for donor nephrectomy: Is CT superior to MRI?]. / Évaluation préopératoire du nombre de vaisseaux chez le donneur de rein vivant. La TDM est-elle supérieure à l'IRM ?

BACKGROUND: computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are both used in the preoperative assessment of vascular anatomy before donor nephrectomy. Our objective was to determine retrospectively and to compare the sensitivity of CTA and MRA imaging in preoperative renal vascularisation in living kidney donors. PATIENTS AND METHODS: between 1999 and 2007, 42 kidney donors were assessed in our center: 27 by MRA, 10 by CTA, and five by both techniques. Images were interpreted using multiplanar reconstructions. Results were compared retrospectively with peroperative findings; discordant cases were re-examined by an experienced radiologist. Numbers of vessels detected with imaging methods was compared with numbers actually found at the operating time. RESULTS: MRA showed 35/43 arteries (Se 81.4 %) and 33/34 veins (Se 97.1 %), and CTA showed 18/18 arteries (Se 100 %) and 15/16 veins (Se 93.8 %). The presence of multiple arteries was detected in only one third of cases (3/9) on MRI scans; this difference was statistically significant. The missed arteries were not detected on second examination of the MRI scans with the knowledge of peroperative findings. CONCLUSION: MRA is less sensitive than CTA for preoperative vascularisation imaging in living renal donors, especially in the detection of multiple renal arteries.

Evaluation of intrarenal oxygenation by blood oxygen level-dependent magnetic resonance imaging in living kidney donors and their recipients: preliminary results.

OBJECTIVE: Blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) is a noninvasive tool to measure modifications in tissue oxygen content. Lower deoxyhemoglobin concentrations due to increased tissue oxygenation induce a longer transverse relaxation time (T2*), thus a stronger MRI signal. We have studied the changes in the kidney oxygenation profiles of living donors and their recipients by BOLD-MRI associated with transplantation and nephrectomy. MATERIALS AND METHODS: Two donor/recipient couples were selected for this preliminary study. BOLD-MRI was performed on the donor on the day prior to surgery, on day 4, and 1 month thereafter, and on the recipient on day 4 and 1 month postsurgery. Mean T2* values were measured in specific target regions in the cortical and medullary regions of each kidney using the T2StarMappingTool (Philips, Eindhoven, Netherlands). Modifications of tissue oxygen profiles were then compared considering the proportionality between T2* values and tissue oxygen content. RESULTS: The clinical courses posttransplantation were uneventful throughout the study; kidney function resumed rapidly. All MRI examinations showed a significantly higher T2* level in the cortex than in the medulla, confirming the notion that the medulla is hypoxic compared to the cortex. Nephrectomy and transplantation induced a significant rise in cortical T2* values in the remnant and transplanted kidney at day 4 and 1 month. Medullary T2* level only increased in the transplanted kidney. CONCLUSIONS: Profound modifications in renal oxygenation intervene following transplantation and nephrectomy. BOLD-MRI may be a useful tool to explore these modifications and possibly identify pathological patterns.

Analysis of the French national evaluation of radiology residents.

PURPOSE: In France, a national evaluation is given annually to radiology residents. The aim of this study was to perform both a docimological analysis of the quality of the questionnaire and a statistical analysis of the results. MATERIALS AND METHODS: This retrospective study, which included French radiology residents from Year 1 to Year 5 of residency, was performed from 2015 to 2017 across 25 medical universities in France. Both qualitative and quantitative docimological analyses were performed as assessed by the Cronbach alpha coefficient, the difficulty of question (PDI), and the coefficient of discrimination (Rir). Results to the questionnaire were compared between years of residency. RESULTS: The results of the analysis confirmed the quality of the questionnaire (Cronbach alpha coefficient=0.71, mean [PDI=0.40]) though the majority of questions could be answered by memory rather than cognitive ability. The mean Rir was 0.02, indicating that students could not be certified using only the questionnaire. The results measuring resident level of knowledge were moderate, with mean results ranging from 9.2/20 at the first year to 11.3/20 at the fifth year of residency (P<0.001). There were no significant differences in results obtained between the third, fourth, and fifth year of residency but results were significantly different among university hospitals. CONCLUSION: Even if close interactions exist between learning and pedagogic environment, our results suggest that it may be useful to further develop an evaluation process in relation with pedagogic instructions in order to provide more optimal training.

[Early embolization in the non-operative management of blunt splenic injuries: a retrospective multicenter study]. / L'embolisation précoce dans le traitement non opératoire des traumatismes fermés de la rate. Etude rétrospective multicentrique.

AIM OF THE STUDY: Splenic artery embolization has been used as an adjunct to the non-surgical management of blunt splenic injury. No consensus on its indications has emerged from the literature. This multicentric study aimed to evaluate the results of this technique in France. PATIENTS AND METHODS: Between March 2000 and April 2006, 22 patients older than 15 years of age (mean age 29, range: 15-59) with splenicv rupture due to blunt trauma underwent splenic artery embolization in six Level I Trauma Centers in France. Splenic rupture was classified Moore II in 3 cases, Moore III in 12 cases, and Moore IV in 7 cases. Angiography was performed within 4 hours of admission in half of the cases. The main indications for splenic artery embolization were: extravasation of contrast medium on CT scan (10 cases, 45%); early pseudo-aneurysm (6 cases, 23%); hypotension despite fluid resuscitation and/or progressive need for transfusion (5 cases, 22%). RESULTS: There was no mortality. Nine patients experienced complications (41%) including 6 (27%) who developed left pleural effusion. Two patients eventually underwent splenectomy (one for persistent hemorrhage, one for splenic necrosis). The overall splenic salvage rate was 91%. CONCLUSION: Splenic artery embolization is a valuable techniche that hels to lower the rate of splenectomy for traumatic splenic rupture with relatively low morbidity.

Non-conform diagnostic management of pulmonary embolism suspected patients is responsible for a higher risk of thrombotic event occurrence.

The aim of this 3-month follow-up prospective pragmatic study was to evaluate the implementation of a pulmonary embolism (PE) diagnostic strategy in clinical practice. One thousand and one hundred thirty-four consecutive in- and outpatients with clinically suspected PE were enrolled into a sequential diagnostic algorithm in which vascular medical unit plays a pivotal role in advising physicians and suggesting the most appropriate tests according to the diagnostic algorithm. In this observational study, patients that followed the proposed work-up were attributed to a so-called "conform group". Patients in whom diagnostic work-up was not according to protocol were attributed to a "non-conform group". Nine hundred and ninety-seven patients (87.9%) had a conform work-up, and 137 patients a non-conform work-up according to the proposed diagnostic algorithm. The non-conform work-up directly increased in relation to the age of the referred patients. PE was ruled out in 907 (80%) patients of whom 787 (86.8%) were in the conform group. Of the 797 patients who did not receive anticoagulant drugs, follow-up was obtained in 792 (99.4%). Among these patients, the incidence of acute thromboembolic events during the 3-month follow-up period was different in the group of patients that had a conform work-up (1%, [95% CI, 0.5-2.1%]) from the non-conform group patients (4.5%, [95% CI, 2-10.2%]. Therefore patients from the non-conform group have an independent increased risk to develop a thromboembolic event during the follow-up, adjusted odds ratio 3.3 [1.1-10, 95% CI]. Therefore we demonstrated that a non-conform diagnostic management strategy is associated with a higher risk of thrombotic event occurrence.

Evaluation of the clinical benefit of an electromagnetic navigation system for CT-guided interventional radiology procedures in the thoraco-abdominal region compared with conventional CT guidance (CTNAV II): study protocol for a randomised controlled trial.

BACKGROUND: Interventional radiology includes a range of minimally invasive image-guided diagnostic and therapeutic procedures that have become routine clinical practice. Each procedure involves a percutaneous needle insertion, often guided using computed tomography (CT) because of its availability and usability. However, procedures remain complicated, in particular when an obstacle must be avoided, meaning that an oblique trajectory is required. Navigation systems track the operator's instruments, meaning the position and progression of the instruments are visualised in real time on the patient's images. A novel electromagnetic navigation system for CT-guided interventional procedures (IMACTIS-CT®) has been developed, and a previous clinical trial demonstrated improved needle placement accuracy in navigation-assisted procedures. In the present trial, we are evaluating the clinical benefit of the navigation system during the needle insertion step of CT-guided procedures in the thoraco-abdominal region. METHODS/DESIGN: This study is designed as an open, multicentre, prospective, randomised, controlled interventional clinical trial and is structured as a standard two-arm, parallel-design, individually randomised trial. A maximum of 500 patients will be enrolled. In the experimental arm (navigation system), the procedures are carried out using navigation assistance, and in the active comparator arm (CT), the procedures are carried out with conventional CT guidance. The randomisation is stratified by centre and by the expected difficulty of the procedure. The primary outcome of the trial is a combined criterion to assess the safety (number of serious adverse events), efficacy (number of targets reached) and performance (number of control scans acquired) of navigation-assisted, CT-guided procedures as evaluated by a blinded radiologist and confirmed by an expert committee in case of discordance. The secondary outcomes are (1) the duration of the procedure, (2) the satisfaction of the operator and (3) the irradiation dose delivered, with (4) subgroup analysis according to the expected difficulty of the procedure, as well as an evaluation of (5) the usability of the device. DISCUSSION: This trial addresses the lack of published high-level evidence studies in which navigation-assisted CT-guided interventional procedures are evaluated. This trial is important because it addresses the problems associated with conventional CT guidance and is particularly relevant because the number of interventional radiology procedures carried out in routine clinical practice is increasing. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01896219 . Registered on 5 July 2013.

Phantom evaluation of a navigation system for out-of-plane CT-guided puncture.

OBJECTIVE: The purpose of this phantom study was to assess a new real time electromagnetically-guided navigation system and compare it to standard computed tomography (CT) guidance. MATERIAL AND METHODS: A prospective, randomized, comparative study was carried out over a two-day period. Operators without prior experience on the new navigation system sequentially attempted to puncture two 6 mm-diameter targets (one attempt for each target) with out-of-plane trajectories using both the standard CT-guided method and the new navigation station (NAV method). RESULTS: Intention-to-treat analysis was performed for 54 operators. Twenty-two operators out of 54 (40.7%) reached the target on first attempt with the NAV method versus none (0%) using CT-guidance (P<0.001). The median distance of the puncture from the center of the target was 3.7mm [Q1-Q3=2-6.7] using NAV versus 15 mm [10-20] using CT-guidance (P<0.001). Overall planning and puncture time were shorter using NAV: 76s [50-118] versus 214s [181-264] using CT-guidance (P<0.001). CONCLUSION: Novice operators consistently performed faster and more accurate phantom punctures with out-of-plane trajectories using the electromagnetically-guided navigation system than with the standard CT-guided method.

Ultrasonographic assessment of liver fibrosis with computer-assisted analysis of liver surface irregularities.

PURPOSE: The goal of this study was to evaluate the diagnostic accuracy of a software program that automatically analyzes the liver surface to diagnose significant fibrosis, by comparing it to the subjective analysis of a radiologist and to transient elastography (Fibroscan(®)). PATIENTS AND METHODS: One hundred fourteen patients with chronic liver disease were included in the study. They underwent liver biopsy, FibroScan(®) and ultrasonographic examination of the liver surface. The liver surface was analyzed by a software program that gave a score of surface irregularities. This evaluation was compared to subjective analysis by a radiologist expert in liver imaging and by two general radiologists. RESULTS: Fifty percent of the patients had significant fibrosis according to the METAVIR score. The AUROC for the diagnosis of significant fibrosis by the software program was 0.80 (95%CI: 0.71-0.87), which was equivalent (P=0.86) to that of FibroScan(®) (0.81; 95%CI: 0.71-0.89). Results of the subjective analysis by the expert radiologist were poorer than those of the software analysis (P=0.02) (AUROC=0.66; 95%CI: 0.56-0.75). Interobserver agreement among radiologists was poor (0.25

Registration of real and CT-derived virtual bronchoscopic images to assist transbronchial biopsy.

This paper describes research work motivated by an innovative medical application: computer-assisted transbronchial biopsy. This project involves the registration, with no external localization device, of a preoperative three-dimensional (3-D) computed tomography (CT) scan of the thoracic cavity (showing a tumor that requires a needle biopsy), and an intraoperative endoscopic two-dimensional (2-D) image sequence, in order to provide assistance in transbronchial puncture of the tumor. Because of the specific difficulties resulting from the data being processed, a multilevel strategy was introduced. For each analysis level, the relevant information to process and the corresponding algorithms were defined. This multilevel strategy, thus, provides the best possible accuracy. Original image processing methods were elaborated, dealing with segmentation, registration and 3-D reconstruction of the bronchoscopic images. In particular, these methods involve adapted mathematical morphology tools, a "daemon-based" registration algorithm, and a model-based shape-from-shading algorithm. This pilot study presents the application of these algorithms to recorded bronchoscopic video sequences for five patients. The preliminary results presented here demonstrate that it is possible to precisely localize the endoscopic camera within the CT data coordinate system. The computer can thus synthesize in near real-time the CT-derived virtual view that corresponds to the actual endoscopic view.

[Interpretation of chest radiographs in the intensive care unit: a hard- versus soft-copy comparative study]. / Interprétation des clichés thoraciques en réanimation chirurgicale: étude comparative film/écran.

PURPOSE: To compare the reliability of hard- versus soft-copy interpretation of intensive care unit chest radiographs, using a non-specialized standard resolution computer screen. MATERIALS AND METHODS: 104 chest radiographs were included in this study. Three physicians (one radiology resident, one intensive care unit resident and one experienced intensive care unit physician) gave their interpretations on computerized grids. Results were analyzed statistically using ROC curves and Kappa (kappa) index of concordance with experts. RESULTS: Results for reanimation equipment detection are almost independent from the modality (kappa(soft-copy)=0.891+/-0.037, kappa(hard-copy)=0.899+/-0.037). Regarding pathology detection, a global analysis only shows a difference at the limits of significance to the advantage of hard-copy films (kappa(soft)=0.514 +/-0.028, kappa(hard)=0.572+/-0.028). Overall results were significantly better for the radiologist compared to the intensive care unit physicians (kappa(radiologist)=0.751+/-0.048, kappa(intensive-care)=0.405+/-0.048). CONCLUSION: Concerning the task that is studied here, which requires only routine computer equipment, our results suggest that human factors can be more important than material factors.

Blunt splenic injury: outcomes of proximal versus distal and combined splenic artery embolization.

PURPOSE: To assess clinical outcomes of blunt splenic injuries (BSI) managed with proximal versus distal versus combined splenic artery embolization (SAE). MATERIALS AND METHODS: All consecutive patients with BSI admitted to our trauma centre from 2005 to 2010 and managed with SAE were reviewed. Outcomes were compared between proximal (P), distal (D) or combined (C) embolization. We focused on embolization failure (splenectomy), every adverse events occurring during follow up and material used for embolization. RESULTS: Fifty patients were reviewed (P n = 18, 36%; D n = 22, 44%; C n = 8, 16%). Mean injury severity score was 20. The technical success rate was 98%. Four patients required splenectomy (P n = 1, D n = 3, C n = 0). Clinical success rate for haemostasis was 92% (4 re-bleeds: P n = 2, D n = 2, C n = 0). Outcomes were not statistically different between the materials used. Adverse events occurred in 65% of the patients during follow up. Four percent of the patients developed major complications and 56% developed minor complications attributable to embolization. There was no significant difference between the 3 groups. CONCLUSION: SAE had an excellent success rate with adverse events occurring in 65% of the patients and no significant differences found between the embolization techniques used. Proximal preventive embolization appears to protect in high-grade traumatic injuries.

Biliary obstruction: not always simple!

Exploration of biliary obstruction may involve many imaging methods and a large number of people. Radiologists, hepato-gastro-enterologists and surgeons may examine using ultrasound, CT, MRI, endoscopic ultrasonography, and percutaneous, intraoperative or endoscopic retrograde cholangiography. Interpreting radiological examinations and choosing an optimal strategy can be difficult. The aim of this paper is therefore: to explain how to explore a clinical and laboratory picture of biliary obstruction using imaging, by presenting its main causes, the methods of exploring them and their radiological signs; to suggest suitable exploration strategies; and to illustrate some of the traps that can make it difficult to diagnose the cause of the obstruction.

Infections of the right hypochondrium.

Among the infectious diseases of the right hypochondrium, cholecystitis, cholangitis, and liver abscesses predominate. These are frequently encountered diseases, but they can still raise questions in daily practice. In this elaboration, we will thus address and illustrate: the major infectious diseases of the liver and gallbladder, and their radiological features; the potential interpretation problems and differential diagnoses; the diagnostic and therapeutic strategies used in imaging to manage infections of the right hypochondrium.

An overview of computer-integrated surgery and therapy.

Computer-integrated surgery and therapy (CIST): Methods and systems to help the surgeon or the physician use multimodality data (mainly medical images) in a rational and quantitative way, in order to plan but also to perform medical interventions through the use of passive, semi-active, or active guiding systems.

Computer-assisted bronchoscopy: aims and research perspectives.

The introduction of spiral computed tomography (CT) of the thoracic cavity has allowed the development of new visualization tools. These tools provide a three-dimensional (3-D) endoluminal reconstruction of the tracheobronchial tree, as it would be viewed through a fibroscopic instrument. However, 3-D reconstruction techniques cannot replace conventional fibroscopy, which remains indispensable for obtaining histological samples. Furthermore, when CT-detected mediastinal or parenchymal lesions are not seen during fiberoptic bronchoscopy, guiding transbronchial needle biopsy is a major challenge. Computer-guided transbronchial biopsy involves the fusion of image data from both CT slices and bronchoscopic video sequences. This fusion is described in this paper in two parts. First, we present a segmentation process, using mathematical morphology operators, in order to analyze the video sequence and localize the bronchoscopic camera within the tracheobronchial tree. Second, we present tools used to match this localization knowledge with CT data. Finally, we produce images that create a bronchoscopic augmented reality, using elements extracted from the CT examination.

Helical CT with multiplanar and three-dimensional reconstruction of nonneoplastic abnormalities of the trachea.

Helical CT is being increasingly used for the evaluation of suspected tracheal diseases. Although nonneoplastic and noninfectious diseases of the trachea are rare, their appearance on CT images may be highly suggestive of the diagnosis. High quality multiplanar and 3D reconstructions including 3D surface-shaded display and virtual bronchoscopy are helpful to characterize tracheal abnormalities and to demonstrate the location and extent of the diseases.