Radiological outcome of postoperative sagittal balance on standing radiographs in comparison to intraoperative radiographs in prone position when performing lumbar spinal fusion.

PURPOSE: Aim of this study is to show the outcome of postoperatively measured lumbar lordosis in upright position in comparison to the intraoperatively estimated lumbar lordosis in prone position, as the lumbar lordosis is one of the most important factors for the clinical outcome after spinal fusion. MATERIALS AND METHODS: Eighty-two patients, receiving lumbar fusion were included in this retrospective study. Intraoperative radiographs were scanned. Then radiographs of the whole spine pre- and postoperatively, as well as 1 year after surgery were measured by a spine surgeon and a radiologist. The visible segment lordosis angles were measured and compared (L2-S1, L3-S1, L4-S1, L5-S1). In addition, the pelvic parameters pelvic incidence, pelvic tilt and sacral slope were measured pre- and postoperatively. RESULTS: The intraobserver reliability was almost perfect. The mean lordosis angle L4-S1 was 32.6° ± 7.8° intraoperatively and 29° ± 10.8° postoperatively. A linear correlation of these two measurements can be seen. In mean, the postoperative lordosis is 4° smaller than intraoperatively. This trend can also be seen in the level L3-S1. In levels L2-S1 and L5-S1 the postoperative values were slightly higher than intraoperatively, but without any significance. Also, 1 year after surgery there were no significant changes in global lumbar lordosis. CONCLUSION: Measuring lordosis angles intraoperatively resulted in almost the same values as measurements in standing plane radiographs postoperatively, despite prone position. These findings could especially be shown for the level L4-S1. The intraobserver reliability was almost perfect for both, intra- and postoperative measurements. In conclusion, the intraoperative measurement of a lumbar lordosis angle can perfectly predict the postoperative result.

Added value of Gd-EOB-DTPA-enhanced Hepatobiliary phase MR imaging in evaluation of focal solid hepatic lesions.

BACKGROUND: Correct characterization of focal solid hepatic lesions has always been a challenge and is of great diagnostic and therapeutic relevance. The purpose of this study was to determine the added value of hepatobiliary phase images in Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) for differentiating focal solid hepatic lesions. METHODS: In this retrospective trial 84 consecutive patients underwent Gd-EOB-DTPA-enhanced MR examinations. MRI was conducted for 64 patients with malignant focal hepatic lesions (34 hepatocellular carcinoma (HCC), 30 metastases) and for 20 patients with benign hepatic lesions (14 focal nodular hyperplasia (FNH), 3 adenoma, 3 hemangioma). Five radiologists independently reviewed three sets of MR images by means of a 5-point confidence scale from score 1 (definitely benign) to score 5 (definitely malignant): set 1: unenhanced images; set 2: unenhanced and Gd-EOB-DTPA-enhanced dynamic images; set 3: hepatobiliary phase images in addition to set 2. Accuracy was assessed by the alternative free-response receiver operating characteristic curve (Az) and the index of diagnostic performance was calculated. RESULTS: Diagnostic accuracy was significantly improved by the addition of Gd-EOB-DTPA-enhanced dynamic images: Az in set 1 was 0.708 and 0.833 in set 2 (P = 0.0002). The addition of hepatobiliary phase images increased the Az value to 0.941 in set 3 (set 3 vs set 2, P < 0.0001; set 3 vs set 1, P < 0.0001). The index of diagnostic performance was lowest in set 1 (45%), improved in set 2 (71%), and highest in set 3 (94%). CONCLUSIONS: Hepatobiliary phase images obtained after Gd-EOB-DTPA-enhanced dynamic MRI improve the differentiation of focal solid hepatic lesions.

Diagnostic value of a hand-carried ultrasound device for free intra-abdominal fluid and organ lacerations in major trauma patients.

BACKGROUND: Technological progress has led to the introduction of hand-carried ultrasound (HCU) imagers in clinical workflow. The aim of this study is to analyse whether examination with a HCU device is a rapid and reliable alternative to contrast-enhanced multidetector CT (MDCT) scans in diagnosis of free intra-abdominal fluid and organ lacerations in major trauma patients. METHODS: 31 major trauma patients with an injury severity score >15 and the necessity of a MDCT scan (standard of reference) were enrolled prospectively to this study, and additionally examined with a HCU, according to 'focused assessment with sonography for trauma' principles for the assessment of organ lacerations and free intra-abdominal fluid. The HCU device employed was of the latest generation. Statistical analysis was performed using PASW V.18. RESULTS: Four patients were diagnosed with free intra-abdominal fluid (prevalence 12.9%). HCU showed a sensitivity and specificity of 75% and 100%, respectively. Positive predictive value and negative predictive value were 100% and 96%, respectively. Five patients had organ lacerations (prevalence 16.1%). In these cases, the HCU was able to detect organ lacerations with a sensitivity and specificity of 80% and 100%, respectively. Therefore, a positive predictive value and negative predictive value of 100% and 96%, respectively, were calculated. CONCLUSION: In major trauma patients, examination with HCU according to the 'focused assessment with sonography for trauma' principles for the diagnosis of organ lacerations and free intra-abdominal fluid is a reliable and rapid alternative to MDCT scans and can help save precious time in emergency situations, and should, additionally, be evaluated in the pre-clinical workflow.

Influence of percutaneous abscess drainage on severe postoperative septic complications in patients with Crohn's disease.

PURPOSE: Severe postoperative intra-abdominal septic complications (IASC) such as an anastomotic leak, intra-abdominal abscess, and fistula are significantly associated with the presence of spontaneous intra-abdominal abscess at the time of laparotomy in patients with Crohn's disease (CD). The purpose of this study was to compare the incidence of severe postoperative IASC in patients undergoing intestinal resections with and without preoperative percutaneous abscess drainage (PAD) before definitive surgery. METHODS: Using a prospective surgical database, we searched for patients with CD and spontaneous intra-abdominal abscesses who underwent intestinal resection at our hospital from May 2005 to February 2009. Postoperative IASC were defined as anastomotic leaks, abscess, and fistula within 1 month after surgery. We compared the incidence of postoperative IASC in patients with (group I) and without (group II) preoperative PAD (Fisher's exact test). RESULTS: We identified 25 patients (15 men, 10 women; mean age, 31 years) with spontaneous intra-abdominal abscesses. PAD was performed in 12 of 25 patients (48%), with an average of 37 days before surgery (range, 6-83 days). The overall rate of postoperative IASC was 48% (12 of 25 patients). In group I, postoperative IASC occurred in 3 of 12 patients (25%). In group II, postoperative IASC were assessed in 9 of 13 patients (69%). The differences between these two groups were considered to be statistically significant (p = 0.04). CONCLUSION: PAD of intra-abdominal abscesses before surgery could significantly reduce the occurrence of severe postoperative IASC in patients with CD.

Structured Reporting of Whole-Body Trauma CT Scans Using Checklists: Diagnostic Accuracy of Reporting Radiologists Depending on Their Level of Experience. / Strukturierte Befundung von Polytrauma-CTs mit Checklisten: Diagnostische Genauigkeit in Abhängigkeit von der Erfahrung des Radiologen.

PURPOSE: Evaluation of the diagnostic accuracy of a checklist-style structured reporting template in the setting of whole-body multislice computed tomography in major trauma patients depending on the level of experience of the reporting radiologist. MATERIALS AND METHODS: A total of 140 major trauma scans with the same protocol were included in this retrospective study. In a purely trial-intended reading, the trauma scans were analyzed by three radiologists with different levels of experience (resident, radiologist with 3 years of experience after board certification, and radiologist with 7 years of experience after board certification). The aim was to fill in the checklist 1 template within one minute to immediately diagnose management-altering findings. Checklist 2 was intended for the analysis of important trauma-related findings within 10 minutes. Reading times were documented. The final radiology report and the documented injuries in the patient's medical record were used as gold standard. RESULTS: The evaluation of checklist 1 showed a range of false-negative reports between 5.0 % and 11.4 % with the resident showing the highest accuracy. Checklist 2 showed overall high diagnostic inaccuracy (19.3-35.0 %). The resident's diagnostic accuracy was statistically significantly higher compared to the radiologist with 3 years of experience after board certification (p = 0.0197) and with 7 years of experience after board certification (p = 0.0046). Shorter average reporting time resulted in higher diagnostic inaccuracy. Most of the missed diagnoses were fractures of the spine and ribs. CONCLUSION: By using a structured reporting template in the setting of major trauma computed tomography, less experienced radiologists reach a higher diagnostic accuracy compared to experienced readers. KEY POINTS: · In the setting of a pure trial reading, the diagnostic inaccuracy of template-based reporting of major trauma CT examinations is high.. · Fractures in general and especially of the vertebral bodies and ribs were the most commonly missed diagnoses.. · In a study setting, less experienced radiologists seem to reach a higher diagnostic accuracy when using a structured reporting approach.. CITATION FORMAT: · Dendl LM, Pausch AM, Hoffstetter P et al. Structured Reporting of Whole-Body Trauma CT Scans Using Checklists: Diagnostic Accuracy of Reporting Radiologists Depending on Their Level of Experience. Fortschr Röntgenstr 2021; 193: 1451 - 1460.

High-resolution ultrasound of the midfoot: sonography is more sensitive than conventional radiography in detection of osteophytes and erosions in inflammatory and non-inflammatory joint disease.

This study aimed to compare the diagnostic value of ultrasonography to conventional radiography in detecting osteophytes and erosions in the midfoot joints in patients suffering from inflammatory and non-inflammatory joint disease. Patients with current foot radiographs were included and stratified in two cohorts: inflammatory and non-inflammatory joint disease. The ten midfoot joints of each foot were evaluated by conventional radiography assessing the presence of osteophytes and erosions and by ultrasonography determining the presence of osteophytes, erosions, and joint effusion. Power Doppler activity was scored semi-quantitatively from 0 to 3. A total of 2445 joints in 124 patients (90 with inflammatory joint disease, 34 with non-inflammatory joint disease) were assessed. Ultrasonography detected significantly more osteophytes than conventional radiography (344; 14.1% vs. 13; 0.5%), as well as more erosions (60; 2.5% vs. 3; 0.1%). There was weak agreement between the two modalities (κ-statistic 0.029-0.035). Power Doppler ultrasonography demonstrated no significant difference in hyperperfusion comparing patients with inflammatory joint disease and non-inflammatory joint disease. Ultrasonography of the midfoot is more sensitive than conventional radiography in the detection of osteophytes and erosions in patients suffering from inflammatory and non-inflammatory joint disease. Thus, midfoot ultrasonography may be a useful tool in the diagnosis of joint diseases as rheumatoid arthritis and osteoarthritis.

Magnetic Resonance Imaging of the Axial Skeleton in Patients With Spondyloarthritis: Distribution Pattern of Inflammatory and Structural Lesions.

PURPOSE: Spondyloarthritis is a chronic inflammatory disorder of the musculoskeletal system driven by systemic enthesitis and typically involving the axial skeleton, ie, the spine and the sacroiliac joints. The purpose of this study was to assess the distribution pattern of inflammatory and structural magnetic resonance imaging (MRI) findings in spondyloarthritis. METHODS: Retrospective study of 193 patients with axial spondyloarthritis who received MRI of the spine and the sacroiliac joints. We quantitatively assessed inflammatory and structural lesions using established MRI-based scoring methods. The significance of the differences between gender, HLA-B27 status, and spine and sacroiliac involvement was determined. RESULTS: In total, 174 patients (90.2%) showed a sacroiliac involvement and 120 patients (62.2%) a combined involvement of the sacroiliac joints and the spine. An isolated sacroiliac involvement was found in 54 patients (28.0%) and an isolated spine involvement in 19 patients (9.8%). The sacroiliac joint was significantly more involved in men than in women (P < .01), and men had significantly higher scores for structural lesions (P < .001). The subgroup of HLA-B27-positive patients showed a significantly higher percentage of sacroiliac involvement compared with HLA-B27-negative patients (P < .05). CONCLUSIONS: Spondyloarthritis is a systemic disorder predominantly involving the sacroiliac joints. However, the entire axial skeleton may be affected. In particular, HLA-B27-negative women show atypical manifestations without sacroiliac involvement. Magnetic resonance imaging in spondyloarthritis should cover the entire axial skeleton, ie, sacroiliac joints and the spine to meet the pathophysiology of this disorder and capture the true extent of inflammatory and structural lesions.

Diagnostic significance of rib series in minor thorax trauma compared to plain chest film and computed tomography.

BACKGROUND: Rib series (RS) are a special radiological technique to improve the visualization of the bony parts of the chest. OBJECTIVES: The aim of this study was to evaluate the diagnostic accuracy of rib series in minor thorax trauma. METHODS: Retrospective study of 56 patients who received RS, 39 patients where additionally evaluated by plain chest film (PCF). All patients underwent a computed tomography (CT) of the chest. RS and PCF were re-read independently by three radiologists, the results were compared with the CT as goldstandard. Sensitivity, specificity, negative and positive predictive value were calculated. Significance in the differences of findings was determined by McNemar test, interobserver variability by Cohens kappa test. RESULTS: 56 patients were evaluated (34 men, 22 women, mean age =61 y.). In 22 patients one or more rib fracture could be identified by CT. In 18 of these cases (82%) the correct diagnosis was made by RS, in 16 cases (73%) the correct number of involved ribs was detected. These differences were significant (p = 0.03). Specificity was 100%, negative and positive predictive value were 85% and 100%. Kappa values for the interobserver agreement was 0.92-0.96. Sensitivity of PCF was 46% and was significantly lower (p = 0.008) compared to CT. CONCLUSIONS: Rib series does not seem to be an useful examination in evaluating minor thorax trauma. CT seems to be the method of choice to detect rib fractures, but the clinical value of the radiological proof has to be discussed and investigated in larger follow up studies.

Tumor-Induced Osteomalacia: Increased Level of FGF-23 in a Patient with a Phosphaturic Mesenchymal Tumor at the Tibia Expressing Periostin.

In our case, a 45-year-old male patient had multiple fractures accompanied by hypophosphatemia. FGF-23 levels were significantly increased, and total body magnetic resonance imaging (MRI) revealed a tumor mass located at the distal tibia leading to the diagnosis of tumor-induced osteomalacia (TIO). After resection of the tumor, hypophosphatemia and the increased levels of FGF-23 normalized within a few days. Subsequent microscopic examination and immunohistochemical analysis revealed a phosphaturic mesenchymal tumor mixed connective tissue variant (PMTMCT) showing a positive expression of somatostatin receptor 2A (SSTR2A), CD68, and Periostin. Electron microscopy demonstrated a poorly differentiated mesenchymal tumor with a multifocal giant cell component and evidence of neurosecretory-granules. However, the resected margins showed no tumor-free tissue, and therefore a subsequent postoperative radiotherapy was performed. The patient is still in complete remission after 34 months. Tumor resection of PMTMCTs is the therapy of choice. Subsequent radiotherapy in case of incompletely resected tumors can be an important option to avoid recurrence or metastasis even though this occurs rarely. The prognostic value of expression of Periostin has to be evaluated more precisely in a larger series of patients with TIO.

Transarterial embolization of type II endoleaks after EVAR: the role of ethylene vinyl alcohol copolymer (Onyx).

PURPOSE: To determine the feasibility and efficacy of transarterial endoleak embolization using the liquid embolic agent ethylene vinyl alcohol copolymer (Onyx). METHODS: Over a 7-year period eleven patients (6 women, 5 men; mean age 68 years, range 37-83 years) underwent transarterial embolization of a type II endoleak after endovascular aortic aneurysm repair using the liquid embolic agent Onyx. Two patients (18 %) had a simple type II endoleak with only one artery in communication with the aneurysm sac, whereas 9 patients (82 %) had a complex type II endoleak with multiple communicating vessels. We retrospectively analyzed the technical and clinical success of transarterial type II endoleak embolization with Onyx. Complete embolization of the nidus was defined as technical success. Embolization was considered clinically successful when volume of the aneurysm sac was stable or decreased on follow-up CT scans. RESULT: Mean follow-up time was 26.0 (range 6-50) months. Clinical success was achieved in 8 of 11 patients (73 %). Transarterial nidus embolization with Onyx was technically successful in 6 of 11 patients (55 %). In three cases the nidus was embolized without direct catheterization from a more distal access through the network of collateral vessels. CONCLUSION: Onyx is a favorable embolic agent for transarterial endoleak embolization. To achieve the best clinical results, complete occlusion of the nidus is mandatory.

Visualization of thrombotic deposits in extracorporeal membrane oxygenation devices using multidetector computed tomography: a feasibility study.

Despite heparin coating and systemic anticoagulation, thrombotic clot formation is a serious complication in extracorporeal membrane oxygenation (ECMO). We describe our first results of visualization of thrombotic deposits in ECMO devices using advanced multidetector computed tomography (MDCT). A bioline-coated polymethylpentene membrane oxygenator (MO) after 8 days of ECMO treatment (device 1) and a factory-sealed MO serving as an internal quality control (device 2) were analyzed with three-dimensional (3D) visualization volume rendering technique (VRT) using a 0.6 mm3 voxel isotropic MDCT dataset. After the computed tomography (CT) scan, device 1 was anatomically dissected for direct visualization of potential deposits and further analyzed by scanning electron microscopy (SEM). The VRT 3D model based on the MDCT dataset of device 1 showed red-coded areas within the gas exchange surface of the device consistent with fibrous and cellular deposits. These deposits could be confirmed by anatomical dissection of the device and by SEM. Device 2 showed no signs of clot formation in MDCT using the same VRT settings. It was demonstrated that MDCT with VRT is able to detect thrombotic deposits in ECMO devices under ex vivo conditions. MDCT allows direct visualization of the actual thrombus load of a used ECMO device as well as the quantification of the thrombus volume and could, therefore, play a significant role in better understanding the oxygenator thrombosis in modern ECMO treatment.

Quantitative assessment of synovitis in patients with rheumatoid arthritis using fluorescence optical imaging.

INTRODUCTION: To prospectively evaluate quantitative assessment of fluorescence optical imaging (FOI) for differentiation of synovitic from non-synovitic joints in patients suffering from rheumatoid arthritis (RA). METHODS: FOI of the hands was performed in patients with active RA, and a stratified quantitative fluorescence readout (FLRO) of 3 phases (1-120 s; 121-240 s; 241-360 s) was generated for 5 individual joints of the clinical predominant hand (carpal joint, metacarpophalangeal and proximal interphalangeal joints of digits II & III). To dissect the effect of the overall perfusion of the hand from the perfusion due to synovitis, a fluorescence ratio (FLRA) was additionally calculated, dividing each FLRO by the readout of the eponychium of digit II. The mean FLRO and FLRA were compared between joints with absent vs. present synovitis determined by clinical examination, grayscale, color Doppler ultrasonography, or magnetic resonance imaging (MRI). RESULTS: The analysis for 90 individual joints from 18 patients yielded FLRO ranging from 4.4 to 49.0 × 10(3), and FLRAs ranging from 0.37 to 2.27. Overall, the analyses based on the FLRA revealed a higher discrimination than the analyses related to the FLRO, demonstrating most significant differences in phases 2 and 3. A sensitivity of 26/39 (67%) and a specificity of 31/40 (77%) were calculated for FLRA of phase 3 using a cut-off value of more than 1.2 to detect MRI-confirmed synovitis with FOI. CONCLUSIONS: FOI has a potential for visualizing synovitis in subjects with RA. For adequate FOI interpretation, quantitative analysis should be based on the novel FLRA calculated for phases 2 and 3.

Volume navigation with contrast enhanced ultrasound and image fusion for percutaneous interventions: first results.

OBJECTIVE: Assessing the feasibility and efficiency of interventions using ultrasound (US) volume navigation (V Nav) with real time needle tracking and image fusion with contrast enhanced (ce) CT, MRI or US. METHODS: First an in vitro study on a liver phantom with CT data image fusion was performed, involving the puncture of a 10 mm lesion in a depth of 5 cm performed by 15 examiners with US guided freehand technique vs. V Nav for the purpose of time optimization. Then 23 patients underwent ultrasound-navigated biopsies or interventions using V Nav image fusion of live ultrasound with ceCT, ceMRI or CEUS, which were acquired before the intervention. A CEUS data set was acquired in all patients. Image fusion was established for CEUS and CT or CEUS and MRI using anatomical landmarks in the area of the targeted lesion. The definition of a virtual biopsy line with navigational axes targeting the lesion was achieved by the usage of sterile trocar with a magnetic sensor embedded in its distal tip employing a dedicated navigation software for real time needle tracking. RESULTS: The in vitro study showed significantly less time needed for the simulated interventions in all examiners when V Nav was used (p<0.05). In the study involving patients, in all 10 biopsies of suspect lesions of the liver a histological confirmation was achieved. We also used V Nav for a breast biopsy (intraductal carcinoma), for a biopsy of the abdominal wall (metastasis of ovarial carcinoma) and for radiofrequency ablations (4 ablations). In 8 cases of inflammatory abdominal lesions 9 percutaneous drainages were successfully inserted. CONCLUSION: Percutaneous biopsies and drainages, even of small lesions involving complex access pathways, can be accomplished with a high success rate by using 3D real time image fusion together with real time needle tracking.

Magnetic resonance enterography with and without biphasic contrast agent enema compared to conventional ileocolonoscopy in patients with Crohn's disease.

BACKGROUND: Magnetic resonance imaging (MRI) of the bowel is a valuable diagnostic tool for assessing disease activity in patients with inflammatory bowel disease (IBD). We compared magnetic resonance enterography (MRE) with and without water enema to conventional ileocolonoscopy to evaluate the advantage of a water enema for MRI diagnostics of Crohn's disease (CD). METHODS: We prospectively evaluated 50 patients with known CD. MRE with enema was performed in 23 cases, whereas 27 patients received an MRE without enema. All patients underwent conventional ileocolonoscopy. We assessed the degree of inflammation in both modalities, evaluating up to seven bowel segments in each patient. We compared MRE with and without rectal enema to each other and to conventional ileocolonoscopy. RESULTS: MRE achieved a sensitivity and specificity of 100% and 74%, respectively, for detection of inflammation in the terminal ileum with enema and a sensitivity and specificity of 72% and 87%, respectively, without enema. Considering the colon, MRE with enema had a sensitivity of 79% (specificity 96%), while the examination without enema showed a sensitivity of 38% (specificity 99%). MRE with enema proved statistically superior to MRE without enema in detecting inflammation in the terminal ileum, ascending colon, and rectum (P < 0.05). CONCLUSIONS: MRE with enema is a valuable diagnostic tool for assessing inflammation in CD patients. Water enema is well tolerated and significantly improves detection of inflammation in the terminal ileum. Water enema should therefore be included in MRE protocols for CD patients.

Dynamic magnetic resonance defecography in 10 asymptomatic volunteers.

AIM: Evaluation of the wide range of normal findings in asymptomatic women undergoing dynamic magnetic resonance (MR) defecography. METHODS: MR defecography of 10 healthy female volunteers (median age: 31 years) without previous pregnancies or history of surgery were evaluated. The rectum was filled with 180 mL gadolinium ultrasound gel mixture. MR defecography was performed in the supine position. The pelvic floor was visualized with a dynamic T2-weighted sagittal plane where all relevant pelvic floor organs were acquired during defecation. The volunteers were instructed to relax and then to perform straining maneuvers to empty the rectum. The pubococcygeal line (PCGL) was used as the line of reference. The movement of pelvic floor organs was measured as the vertical distance to this reference line. Data were recorded in the resting position as well as during the defecation process with maximal straining. Examinations were performed and evaluated by two experienced abdominal radiologists without knowledge of patient history. RESULTS: Average position of the anorectal junction was located at -5.3 mm at rest and -29.9 mm during straining. The anorectal angle widened significantly from 93° at rest to 109° during defecation. A rectocele was diagnosed in eight out of 10 volunteers showing an average diameter of 25.9 mm. The bladder base was located at a position of +23 mm at rest and descended to -8.1 mm during defecation in relation to the PCGL. The bladder base moved below the PCGL in six out of 10 volunteers, which was formally defined as a cystocele. The uterocervical junction was located at an average level of +43.1 mm at rest and at +7.9 mm during straining. The uterocervical junction of three volunteers fell below the PCGL; described formally as uterocervical prolapse. CONCLUSION: Based on the range of standard values in asymptomatic volunteers, MR defecography values for pathological changes have to be re-evaluated.

Middle ear of human and pig: a comparison of structures and mechanics.

INTRODUCTION: Animal studies are an essential method to evaluate implants for the middle ear prior to clinical studies. New Zealand rabbits, guinea pigs and chinchillas are, among other small mammals, well established animal models, but their auditory system is significantly smaller compared to human. Hence, the suitability of the domestic pig (sus scrofa domesticus) as a new animal model for research on the middle ear (ME), that would match the human in size, was investigated. METHODS: Thirty halved pig heads were obtained from the butcher and each middle ear was dissected. Using a digital light microscope, several anatomical magnitudes were determined for 24 specimens, namely the planar projected area of the tympanic membrane (TM), in relation to the stapes footplate as well as the dimensions and weight of the ossicles, in order to determine the effective lever ratios. Using normal and micro computed tomography (CT), six porcine temporal bones were scanned and the geometric data obtained were transferred into a finite element model (FEM) simulation of the porcine middle ear. The transfer function was determined and compared to those from humans determined by measurements and simulations, respectively. RESULTS: The anatomy investigated presented itself as highly comparable to that of the human. Differing from literature, no fourth ossicle could be found. The porcine dimensions and lever ratios determined match the humans far better than those of all established animal models. The obtained transfer function was congruent to the human one. This underlines the suitability of the pig as an animal model for middle ear implants.

MR-arterioportography: a new technical approach for detection of liver lesions.

AIM: To evaluate the benefit and effectiveness of MR-arterioportography (MR-AP) to achieve the highest sensitivity for detection and evaluation of hepatocellular carcinoma (HCC). METHODS: Twenty liver cirrhosis patients with suspected HCC were included before transarterial chemoembolization. In all patients double-enhanced Magnetic resonance imaging (MRI) was performed. A bolus of 10 mL Magnevist® was injected through a selectively placed catheter in the superior mesenteric artery and MRI of the liver was performed in arterioportographic phase. Two independent readers evaluated number, size and localization of detected lesions. Diagnostic quality was determined using a 4-point scale. Differences were analyzed for significance using a t-test. Interobserver variability was calculated. RESULTS: In all 20 patients (100%), MR-AP was feasible. Diagnostic quality was, in all cases, between 1 and 2 for both modalities and readers. MR-AP detected significantly more lesions than double-enhanced MRI (102.5 vs. 61, respectively, P < 0.0024). The inter-observer variability was 0.881 for MRI and 0.903 for MR-AP. CONCLUSION: Our study confirmed that the MR-AP as an additional modality for detection of HCC is beneficial, as significantly more lesions were detected compared to MRI with liver-specific contrast.

Comparison of conventional abdominal CT with MR-enterography in patients with active Crohn's disease and acute abdominal pain.

RATIONALE AND OBJECTIVES: Patients with known Crohn's disease (CD) and an acute onset of severe abdominal pain attending an emergency room frequently undergo contrast-enhanced emergency computed tomography (CT) for complication assessment. To assess small bowel changes, an additional dedicated imaging procedure such as magnetic resonance enterography (MRE) is regularly performed. Therefore, these patients undergo two imaging procedures, although the clinical and diagnostic value of such an approach is not known. In a retrospective study, we compared the diagnostic value of a conventional abdominal CT with a dedicated small bowel MRE to assess bowel wall changes as well as typical complications in patients with advanced CD. MATERIALS AND METHODS: We retrospectively evaluated 53 patients with CD having a conventional abdominal multidetector-CT (MD-CT) and MRE within 2 days. Image quality and bowel inflammation was analyzed for each bowel segment. Lymph nodes, abscesses, and fistulas were evaluated. RESULTS: For small bowel and colon assessment, there was no significant difference for image quality between CT and MRE. Inflammation diagnosis was not significantly different between CT (69.4%) and MRE (71.4%). Colonic inflammation was diagnosed in 30.2% based on CT and 14.3% based on MRE. The difference for the detection of lymph nodes was significant (CT 49; MRE 27), whereas the differences between fistula (CT 25, MRE 27) or abscesses (CT and MRE 32) detection were not significant. CONCLUSIONS: In patients with known advanced CD with acute abdominal pain conventional abdominal MD-CT, which is frequently performed as an emergency imaging procedure, is sufficient for bowel wall assessment. Based on our data, additional dedicated small bowel imaging such as MRE seems not to be necessary.