Role of diffusion-weighted imaging in the discrimination of purulent intrasinusal content: A retrospective study.

OBJECTIVES: The objective of this study was to analyse MRI with morphological (T1, T2) and diffusion sequences (DWI, b1000) in patients presenting non-aggressive patterns of sinus opacity and operated on by functional endoscopic sinus surgery (FESS). DESIGN: A retrospective study. SETTING: Diffusion imaging in paranasal sinus pathology remains little known. To date, no imaging system is capable of determining the purulent content of a non-enhanced sinus filling. PARTICIPANTS: We included consecutive patients having undergone FESS in whom MRI of the paranasal sinuses was performed. Subjects were allocated to Case (pus) or Control (no pus) groups depending on sinus content found intraoperatively. FESS was performed for bacterial acute rhinosinusitis, acute exacerbations of chronic rhinosinusitis, non-purulent sinusitis, naso-sinusal polyposis, antrochoanal polyp, isolated polyp, angiomatous polyp and eosinophilic fungal sinusitis. Tumours, mucoceles and fungus balls were excluded. MAIN OUTCOME MEASURES: We analysed T1, T2, b1000 and MRI sequences and ADC map. RESULTS: On univariate analysis, intermediate signal in T2 and high signal in b1000 were associated with Cases (P < 0.001) as were low ADC values (P < 0.001). The difference in mean ADC values between Cases and Controls was statistically significant (respectively, 0.518 vs 2.041 × 10-3  mm2 /sec, P < 0.01). On multivariate analysis, MRI with ADC < 0.725 × 10-3  mm2 /sec and b1000_SI > brain was significantly associated with the case group. MRI with b1000_SI < brain and ADC > 1.450 × 10-3  mm2 /sec was significantly associated with the control group. CONCLUSIONS: Diffusion MRI offers extremely promising results regarding content characterisation of infectious sinus diseases.

Shear Wave Elastography in Head and Neck Lymph Node Assessment: Image Quality and Diagnostic Impact Compared with B-Mode and Doppler Ultrasonography.

The aim of this study was to assess the diagnostic performance of shear wave elastography (SWE) in comparison to B-mode and Doppler ultrasonography in differentiating benign from malignant head and neck lymph nodes (HNLNs). Sixty-two HNLNs from 56 patients were prospectively examined using B-mode, Doppler and SWE. The standard of reference was histopathology or cytology and follow-up. Qualitative malignant criteria (hilum infiltration, cortical hypo-echogenicity, irregular margins, abnormal vessels) were assessed on a five-point scale. Four quantitative parameters were obtained: long axis length, short axis length, short axis/long axis ratio, resistive index and maximum shear elasticity modulus (µmax). Diagnostic performance was analyzed with special emphasis on the sub-centimeter HNLN subgroup. Thirty HNLNs were malignant (48%). µmax intra-observer reproducibility was 0.899 (0.728 in sub-centimeter subgroup). Malignant HNLNs were stiffer (µmax = 72.4 ± 59.0 kPa) compared with benign nodes (µmax = 23.3 ± 25.3 kPa) (p < 0.001). Among the quantitative criteria, µmax had the highest diagnostic accuracy (area under the curve = 0.903 ± 0.042), especially in the sub-centimeter subgroup (area under the curve = 0.929 ± 0.045; p < 0.001) in which the area under the curve was significantly higher compared with the other quantitative criteria (p < 0.05). The additional use of SWE combined with B-mode tended to improve diagnostic accuracy (p > 0.05). SWE is a promising reproducible quantitative tool with which to predict malignant HNLNs, especially sub-centimeter nodes.

The value of a rapid contrast-enhanced angio-MRI protocol in the detection of head and neck paragangliomas in SDHx mutations carriers: a retrospective study on behalf of the PGL.EVA investigators.

OBJECTIVES: To assess the performance of a simplified MRI protocol consisting of a contrast-enhanced three-dimensional MR angiography (CE-MRA) in association with a post-contrast T1-weighted sequence (T1WIV) for the detection of HNPGLs in SDHx mutation carriers. METHODS: This retrospective sub-study is based on the multicenter PGL.EVA cohort, which prospectively enrolled SDHx mutation carriers from 2005 to 2009; 157 index cases or relatives were included. CE-MRA and the T1WIV images were read solely with knowledge of the clinical data but blind to the diagnosis. Sensitivity, specificity and likelihood ratios for the simplified MRI protocol were compared to the full MRI protocol reading results and to the gold standard status obtained through the consensus of an expert committee. RESULTS: The sensitivity and specificity of the readings of the simplified MRI protocol were, respectively, 88.7 % (95 % CI = 78.1-95.3) and 93.7 % (95 % CI = 86.8-97.7) versus 80.7 % (95 % CI = 68.6-89.6) and 94.7 % (95 % CI = 88.1-98.3) for the readings of the full MRI protocol. CONCLUSIONS: The simplified post-contrast MRI with shorter duration (5 to 10 minutes) showed no performance difference compared to the lengthy standard full MRI and can be proposed for the detection of head and neck paragangliomas (HNPGLs) in SDHx mutation carriers. KEY POINTS: • Rapid angio-MRI protocol and the usual lengthy protocol show equal diagnostic performance. • The CE-MRA is the key sequence for the detection of HNPGLs. • The T1WIV sequence assists in localizing HNPGLs.

Magnetic resonance spectroscopy of paragangliomas: new insights into in vivo metabolomics.

Paragangliomas (PGLs) can be associated with mutations in genes of the tricarboxylic acid (TCA) cycle. Succinate dehydrogenase (SDHx) mutations are the prime examples of genetically determined TCA cycle defects with accumulation of succinate. Succinate, which acts as an oncometabolite, can be detected by ex vivo metabolomics approaches. The aim of this study was to evaluate the potential role of proton magnetic resonance (MR) spectroscopy ((1)H-MRS) for identifying SDHx-related PGLs in vivo and noninvasively. Eight patients were prospectively evaluated with single voxel (1)H-MRS. MR spectra from eight tumors (four SDHx-related PGLs, two sporadic PGLs, one cervical schwannoma, and one cervical neurofibroma) were acquired and interpreted qualitatively. Compared to other tumors, a succinate resonance peak was detected only in SDHx-related tumor patients. Spectra quality was considered good in three cases, medium in two cases, poor in two cases, and uninterpretable in the latter case. Smaller lesions had lower spectra quality compared to larger lesions. Jugular PGLs also exhibited a poorer spectra quality compared to other locations. (1)H-MRS has always been challenging in terms of its technical requisites. This is even more true for the evaluation of head and neck tumors. However, (1)H-MRS might be added to the classical MR sequences for metabolomic characterization of PGLs. In vivo detection of succinate might guide genetic testing, characterize SDHx variants of unknown significance (in the absence of available tumor sample), and even optimize a selection of appropriate therapies.

Transjugular intrahepatic porto-systemic shunt is a risk factor for liver dysplasia but not hepatocellular carcinoma: a retrospective study of explanted livers.

BACKGROUND: Conflicting data exist regarding the risk for hepatocellular carcinoma after transjugular intrahepatic porto-systemic shunt (TIPS) insertion in cirrhotic patients. METHODS: We retrospectively analysed histopathological data from 214 patients who were transplanted in our Institution including 68 patients who underwent TIPS placement before transplantation. Pathological lesions from explanted livers, including incidental hepatocellular carcinoma, small cell dysplasia and large cell dysplasia were recorded. RESULTS: Pathological lesions were found in 36.4% of explanted livers. TIPS insertion was an independent risk factor for pathological lesion (HR = 2.11, p < 0.05), concurrently with age (HR = 1.10 per year, p < 0.001) and viral aetiology of cirrhosis (HR = 3.05, p < 0.001). When considering the different type of lesions, TIPS insertion was not associated with an increased risk for hepatocellular carcinoma but was an independent risk factor for liver dysplasia (HR = 2.15, p = 0.042). CONCLUSION: Although a direct relationship between TIPS insertion and hepatocellular carcinoma risk was not demonstrated in this study, the increased frequency of liver dysplasia observed in TIPS-bearing explanted livers deserves further prospective investigations with adequate follow-up.

Cardiac multidetector computed tomography in infective endocarditis: a pictorial essay.

OBJECTIVES: The goals of this pictorial essay are: (1) to set out a multislice computed tomography (MSCT) imaging protocol to assess infective endocarditis (IE); (2) to give an MSCT overview of valvular and peri-valvular involvement during IE; (3) to give a CT overview of septic embolism and infectious pseudoaneurysms during IE. METHODS: MSCT acquisition protocols to assess IE are performed in two different phases: the first acquisition, under electrocardiography (ECG) gating, covers the cardiac structures during first-pass iodine injection; the second acquisition covers the thorax, abdomen, pelvic and cerebral regions. RESULTS: Valvular and peri-valvular lesions during IE are: vegetation-a hypodense, homogeneous, irregular mass on a valve or endocardial structure; perforation-a defect in the leaflet; valvular aneurysm-loss of the homogenous curvature of the leaflet; valvular thickening; peri-valvular abscess; pseudoaneurysm; fistula and disinsertion of a prosthetic valve. Extra-cardiac location could involve all organs. CONCLUSIONS: MSCT can be considered as a useful complement in visualising the cardiac lesions of IE if echocardiography is inconclusive. MSCT is the only imaging modality that provides assessment of valvular and peri-valvular involvement, extra-cardiac lesions, and non-invasive evaluation of the coronary artery anatomy, simultaneously. MAIN MESSAGES: • MSCT provides assessment of coronary anatomy, cardiac and extra-cardiac lesions. • MSCT represents an alternative to echocardiography during IE. • Surgical valve replacement is usually required if vegetation is >10 mm. • Peri-valvular extension (abscesses, pseudoaneurysm and fistulae) required surgical treatment.

Assessment of myocardial partition coefficient of gadolinium (λ) in dilated cardiomyopathy and its impact on segmental and global systolic function.

PURPOSE: 1) To assess the myocardial partition coefficient (λ) of gadolinium quantified using T1 mapping in dilated cardiomyopathy (DCM); and 2) to assess the impact of increased λ on left ventricular (LV) circumferential strain and ejection fraction in DCM. MATERIALS AND METHODS: Seventeen patients with DCM and 11 controls were prospectively included. All patients and controls underwent a 1.5 T MRI using: 1) cine to quantify LV volumes and function; 2) tagging to quantify circumferential strain in mid-LV; 3) T1 mapping before and 9 minutes after contrast injection to quantify R1, ΔR1, and λ; and 4) inversion recovery 3D Flash was used to assess late gadolinium enhancement (LGE) 10 minutes after Gd DOTA injection (0.2 mmol/kg). We used Student's t-test to compare means, Pearson's test for correlation assessment, and a mixed linear model to integrate the dependency between myocardial segments. RESULTS: No difference in median λ was measured between patients with (0.52 [interquartile range = 0.48-0.56]) and without enhancement on LGE (0.51 [0.47-0.54]; P = 0.07). Circumferential strain value measured in each segment was correlated with the λ measured in the corresponding segment (r = 0.55; P < 0.0001). Multivariate analysis revealed a significant link between the λ in each segment and circumferential strain (0.002 ± 0.001; P = 0.009) and also with ejection fraction (-0.001 ± 0.0008; P = 0.04). CONCLUSION: In DCM, λ correlates independently with circumferential strain and ejection fraction, suggesting that there is a link between λ and systolic function.

Prognostic value of preoperative coronary computed tomography angiography in patients treated by orthotopic liver transplantation.

OBJECTIVES: The aim of this study was to assess the feasibility of 64-slice coronary computed tomography (CT) angiography in patients treated by orthotopic liver transplantation, and to compare prognostic values of CT angiography and dobutamine stress echocardiography in the same population. METHODS: Eighty-two consecutive patients, without known coronary artery disease, who underwent orthotopic liver transplantation, were included in this study. A CT angiography was performed along with usual explorations including dobutamine stress echography. A one-year minimal follow-up was performed to seek cardiac events. RESULTS: Fifty-two (65.8%) patients underwent a CT angiography. Thirty-seven (71%) were totally normal or showed nonobstructive coronary plaque, six (12%) showed at least one obstructive coronary plaque greater than 50%. Nine (17%) of the examined patients had at least one nonassessable segment. A total of six (7.6%) major cardiac events occurred in a mean-time follow-up of 17.8 ± 12.7 months. CONCLUSION: CT angiography that is normal or with a nonobstructive coronary plaque has a negative predicting value of 95% [0.82-0.99] for major cardiac adverse events, and of 100% [0.91-1] for clinical coronary events in patients undergoing orthotopic liver transplantation. The prognostic value of CT angiography was comparable with that of dobutamine stress echography.

Incidence, predictors, and prognostic value of intramyocardial hemorrhage lesions in ST elevation myocardial infarction.

BACKGROUND: Intra myocardial hemorrhage lesions (IMH) are underdiagnosed complication of ST elevation myocardial infarction (STEMI). We sought to determine the incidence, predictors and the prognostic value of IMH in STEMI using cardiac MR imaging (CMR) techniques. METHODS: We screened for inclusion consecutive patients with STEMI treated by percutaneous coronary intervention (PCI) within the first 12 hr of evolution. IMH lesions were identified on T2-weighted sequences on CMR between days 4 and 8 after PCI. Adverse cardiac events were defined as a composite of death + severe ventricular arrhythmias + acute coronary syndrome + acute heart failure. RESULTS: N = 114 patients were included and n = 11 patients (10%) presented IMH lesions. Patients with IMH lesions had a larger myocardial infarction extent (25.6 ± 1.8 vs. 13.5 ± 1.0 % LV mass, P < 0.01), microvascular obstructive lesions extent (4.6 ± 1.0 vs. 1.3 ± 0.3% LV mass, P < 0.01) and lower LV ejection fraction (40.7 ± 2.3% vs. 50.7 ± 1.3%, P < 0.01). The value of glycemia at admission was an independent predictor of IMH development (Odd ratio 1.8 [1.1-2.8] per mmol l(-1), P = 0.01). The incidence of adverse cardiac events was higher in the IMH group than in the non-IMH group during the first year following STEMI (P = 0.01, log-rank analysis). Cox regression analysis identified the presence of IMH lesions as an independent predictor of adverse clinical outcome (Hazard Ratio = 2.8 [1.2-6.8], P = 0.02). CONCLUSION: Our study indicates that IMH is a rare but severe finding in STEMI, associated with a larger myocardial infarction and a worse clinical outcome. Per-PCI glycemia might influence IMH development.

Gender differences in response to cold pressor test assessed with velocity-encoded cardiovascular magnetic resonance of the coronary sinus.

BACKGROUND: Gender-specific differences in cardiovascular risk are well known, and current evidence supports an existing role of endothelium in these differences. The purpose of this study was to assess non invasively coronary endothelial function in male and female young volunteers by myocardial blood flow (MBF) measurement using coronary sinus (CS) flow quantification by velocity encoded cine cardiovascular magnetic resonance (CMR) at rest and during cold pressor test (CPT). METHODS: Twenty-four healthy volunteers (12 men, 12 women) underwent CMR in a 3 Tesla MR imager. Coronary sinus flow was measured at rest and during CPT using non breath-hold velocity encoded phase contrast cine-CMR. Myocardial function and morphology were acquired using a cine steady-state free precession sequence. RESULTS: At baseline, mean MBF was 0.63 ± 0.23 mL·g⁻¹·min⁻¹ in men and 0.79 ± 0.21 mL·g⁻¹·min⁻¹ in women. During CPT, the rate pressure product in men significantly increased by 49 ± 36% (p < 0.0001) and in women by 52 ± 22% (p < 0.0001). MBF increased significantly in both men and women by 0.22 ± 0.19 mL·g⁻¹·min⁻¹ (p = 0.0022) and by 0.73 ± 0.43 mL·g⁻¹·min⁻¹ (p = 0.0001), respectively. The increase in MBF was significantly higher in women than in men (p = 0.0012). CONCLUSION: CMR coronary sinus flow quantification for measuring myocardial blood flow revealed a higher response of MBF to CPT in women than in men. This finding may reflect gender differences in endothelial-dependent vasodilatation in these young subjects. This non invasive rest/stress protocol may become helpful to study endothelial function in normal physiology and in physiopathology.

Gadolinium chelate kinetics in cardiac MR imaging of myocarditis: comparison to acute myocardial infarction and impact on late gadolinium enhancement.

OBJECTIVES: To compare the kinetics of gadolinium in myocarditis and myocardial infarction and to establish the best interval between contrast injection and late gadolinium-enhanced (LGE) image acquisition for the diagnosis of acute myocarditis. METHODS: Seventeen patients with acute myocarditis and 12 with acute myocardial infarction underwent Look-Locker sequences before and after administration of 0.2 mmol/kg gadolinium chelate for a period of 14 minutes. The apparent longitudinal relaxation rates (R'1) were calculated from left ventricular blood, enhanced and normal myocardium. LGE cardiac magnetic resonance images were acquired at 5, 10, and 15 minutes after contrast injection. The contrast between enhanced and normal myocardium (Contrastenhaced-normal) was measured, and the quality of the images was analyzed. RESULTS: A faster decline in the R'1 values measured in the areas of myocardial enhancement was recorded in myocarditis than that in myocardial infarction. In myocarditis, the Contrastenhaced-normal values decreased over time (from 60.7 ± 35.1 at 5 minutes vs. 42.1 ± 26.7 at 15 minutes; P = 0.001). However, in myocardial infarction, the Contrastenhaced-normal value remained stable in time (60.7 ± 22.9 at 5 minutes vs. 68.8 ± 16.6 at 15 minutes; P = ns). CONCLUSION: The gadolinium kinetics of acute myocarditis are different from those of acute myocardial infarction. In myocarditis, LGE images acquired 5 minutes after contrast injection provide higher Contrastenhaced-normal and better image quality compared with images taken at later points.

Value of a new multiparametric score for prediction of microvascular obstruction lesions in ST-segment elevation myocardial infarction revascularized by percutaneous coronary intervention.

BACKGROUND: Despite improvement in revascularization strategies, microvascular obstruction (MO) lesions remain associated with poor outcome after ST-segment elevation myocardial infarction (STEMI). AIMS: To establish a bedside-available score for predicting MO lesions in STEMI, with cardiac magnetic resonance imaging (CMR) as the reference standard, and to test its prognostic value for clinical outcome. METHODS: Patients with STEMI of<12 hours' evolution treated by percutaneous coronary intervention (PCI) were included. CMR was performed 4-8 days later, to measure myocardial infarction (MI) extent, left ventricular ejection fraction (LVEF) and volumes, and to identify MO lesions. An MO score was built from multivariable logistic regression results and included clinical, angiographic and electrocardiographic criteria. Adverse cardiovascular events were recorded prospectively after STEMI. RESULTS: We analysed data from 112 patients. MO lesions were found in 63 (56%) patients and were associated with larger MI as assessed by higher peak creatine phosphokinase (3755 ± 351 vs 1467 ± 220 IU, p<0.001), lower LVEF (46.7 ± 1.5 vs 53.4 ± 1.6%, p<0.01) and larger MI extent (18.7 ± 1.2 vs 9.0 ± 1.3% LV, p<0.001) on CMR. MO score>4 accurately identified microcirculatory injuries (sensitivity 84%; specificity 82%) and independently predicted the presence of MO lesions on CMR. MO score>4 predicted adverse cardiovascular events during the first year after STEMI (relative risk 2.60 [1.10-6.60], p=0.03). CONCLUSIONS: MO lesions are frequent in PCI-treated STEMI and are associated with larger MIs. MO score accurately predicted MO lesions and identified patients with poor outcome post-STEMI.

Effectiveness of endovascular embolization with a collagen-based embolic agent (Marsembol) in an animal model.

PURPOSE: To investigate in a porcine experimental model the effectiveness, tissue penetration, and histologic impact of renal artery embolization with a collagen-based nonadhesive embolic agent, marsembol. MATERIALS AND METHODS: Fifteen pigs underwent embolization of one interlobular artery of the renal artery with collagen-resorcinol gel emulsified with Lipiodol and further polymerized with glutaraldehyde-formaldehyde mixture. Angiograms were obtained before, during, and after the procedure. Animals were euthanized at day 0 (n = 3), 1 week (n = 3), or 3 months (n = 7), and flat-panel three-dimensional rotational radiologic images of the kidneys were obtained. Arterial, medullary, and cortical samples were taken for histologic and scanning electron microscopic investigations. RESULTS: Fifteen interlobular renal arteries were successfully embolized by delivering 1.7 mL + or - 0.2 of the embolic agent. All the embolized arteries remained occluded at 3 months, leading to a major atrophy of the embolized portions of the kidneys. Imaging and histologic findings show that the embolic agent provided a distal vessel occlusion and entirely filled the lumen of the arteries up to the glomerular tufts. The homogeneous plug formed by the embolic agent induces very few inflammatory responses. The regenerative tubular processes were arrested at 3 months. CONCLUSIONS: The collagen-based embolic agent described here has the properties required to perform embolization. These specific properties lead to very distal vessel embolization. The embolic agent is effective at 3 months in renal embolization.

Assessment of left ventricular non-compaction in adults: side-by-side comparison of cardiac magnetic resonance imaging with echocardiography.

BACKGROUND: Two-dimensional echocardiography images obtained at end-diastole and end-systole and cardiac magnetic resonance (CMR) images obtained at end-diastole represent the three imaging methodologies validated for diagnosis of left ventricular non-compaction (LVNC). No study has compared these methodologies in assessing the magnitude of non-compaction. AIMS: To compare two-dimensional echocardiography with CMR in the evaluation of patients with suspected LVNC. METHODS: Sixteen patients (48+/-17 years) with LVNC underwent echocardiography and CMR within the same week. Echocardiography images obtained at end-diastole and end-systole were compared in a blinded fashion with those obtained by CMR at end-diastole to assess non-compaction in 17 anatomical segments. RESULTS: All segments could be analysed by CMR, whereas only 238 (87.5%) and 237 (87.1%) could be analysed by echocardiography at end-diastole and end-systole, respectively (p=0.002). Among the analysable segments, a two-layered structure was observed in 54.0% by CMR, 42.9% by echocardiography at end-diastole and 41.4% by echocardiography at end-systole (p=0.006). Similar distribution patterns were observed with the two echocardiographic methodologies. However, compared with echocardiography, CMR identified a higher rate of two-layered structures in the anterior, anterolateral, inferolateral and inferior segments. Echocardiography at end-systole underestimated the NC/C maximum ratio compared with CMR (p=0.04) and echocardiography at end-diastole (p=0.003). No significant difference was observed between CMR and echocardiography at end-diastole (p=0.83). Interobserver reproducibility of the NC/C maximum ratio was similar for the three methodologies. CONCLUSION: CMR appears superior to standard echocardiography in assessing the extent of non-compaction and provides supplemental morphological information beyond that obtained with conventional echocardiography.

Measurement of trabeculated left ventricular mass using cardiac magnetic resonance imaging in the diagnosis of left ventricular non-compaction.

AIMS: To describe a method for measuring trabeculated left ventricular (LV) mass using cardiac magnetic resonance imaging and to assess its value in the diagnosis of left ventricular non-compaction (LVNC). METHODS AND RESULTS: Between January 2003 and 2008, we prospectively included 16 patients with LVNC. During the mean period, we included 16 patients with dilated cardiomyopathy (DCM), 16 patients with hypertrophic cardiomyopathy (HCM), and 16 control subjects. Left ventricular volumes, LV ejection fraction, and trabeculated LV mass were measured in the four different populations. The percentage of trabeculated LV mass was almost three times higher in the patients with LVNC (32 +/- 10%), compared with those with DCM (11 +/- 4%, P < 0.0001), HCM (12 +/- 4%, P < 0.0001), and controls (12 +/- 5%, P < 0.0001). A value of trabeculated LV mass above 20% of the global mass of the LV predicted the diagnosis of LVNC with a sensitivity of 93.7% [95% confidence interval (CI), 71.6-98.8%] and a specificity of 93.7% (95% CI, 83.1-97.8%; kappa = 0.84). CONCLUSION: The method described is reproducible and provides an assessment of the global amount of LV trabeculation. A trabeculated LV mass above 20% of the global LV mass is highly sensitive and specific for the diagnosis of LVNC.

NMR structure of rALF-Pm3, an anti-lipopolysaccharide factor from shrimp: model of the possible lipid A-binding site.

The anti-lipopolysaccharide factor ALF-Pm3 is a 98-residue protein identified in hemocytes from the black tiger shrimp Penaeus monodon. It was expressed in Pichia pastoris from the constitutive glyceraldehyde-3-phosphate dehydrogenase promoter as a folded and (15)N uniformly labeled rALF-Pm3 protein. Its 3D structure was established by NMR and consists of three alpha-helices packed against a four-stranded beta-sheet. The C(34)-C(55) disulfide bond was shown to be essential for the structure stability. By using surface plasmon resonance, we demonstrated that rALF-Pm3 binds to LPS, lipid A and to OM-174, a soluble analogue of lipid A. Biophysical studies of rALF-Pm3/LPS and rALF-Pm3/OM-174 complexes indicated rather high molecular sized aggregates, which prevented us to experimentally determine by NMR the binding mode of these lipids to rALF-Pm3. However, on the basis of striking structural similarities to the FhuA/LPS complex, we designed an original model of the possible lipid A-binding site of ALF-Pm3. Such a binding site, located on the ALF-Pm3 beta-sheet and involving seven charged residues, is well conserved in ALF-L from Limulus polyphemus and in ALF-T from Tachypleus tridentatus. In addition, our model is in agreement with experiments showing that beta-hairpin synthetic peptides corresponding to ALF-L beta-sheet bind to LPS. Delineating lipid A-binding site of ALFs will help go further in the de novo design of new antibacterial or LPS-neutralizing drugs.

Sonographic diagnosis of a cervical vagal schwannoma.

This case report illustrates the role of high-resolution sonography in the preoperative assessment of a schwannoma of the vagus nerve in the neck. Sonography identified the tumor in the right carotid space and determined its origin from the right vagus nerve, facilitating the surgeon's approach to preserve nerve function.

Multidetector computed tomography in reperfused acute myocardial infarction. Assessment of infarct size and no-reflow in comparison with cardiac magnetic resonance imaging.

OBJECTIVES: (1) To determine the accuracy of delayed enhancement multidetector computed tomography (MDCT) in measuring the extent of acute myocardial infarct and no-reflow areas using cardiac magnetic resonance imaging (MRI) as standard of reference and (2) to define the optimum timing between injection and MDCT image acquisition to characterize infarcted myocardium and no-reflow areas after reperfusion therapy. MATERIALS AND METHODS: Nineteen patients were prospectively included after acute myocardial infarction and revascularization. Each patient had an MDCT acquisition before and 5 and 10 minutes after injection of 1.5 mL/kg iodinated contrast medium, and a contrast-enhanced MRI at 5 and 10 minutes after injection of 0.2 mmol/kg gadolinium chelate. We assessed image quality and infarct extent using MDCT and MRI, and we measured parameters related to iodinated contrast media kinetics (DeltaHU and DeltaHU ratio). RESULTS: The areas of hyperenhanced myocardium located on the MDCT corresponded to the occluded vessel located on the coronary angiogram (kappa = 0.9). There were strong correlations between the extent of hyperenhanced infarcted myocardium on MDCT and MRI at 5 minutes (20.4% +/- 2.7% of left ventricle (LV) and 20.9% +/- 2.4%, respectively, R = 0.85; P < 0.0001) and 10 minutes after injection (21.0% +/- 2.9% of LV and 19.4% +/- 2.5%, respectively, R = 0.80; P < 0.0001). However, the correlation between the area of hypoenhanced myocardium measured using MDCT and CMR 5 minutes after injection (R = 0.86; P < 0.0001) was better than the measurement obtained 10 minutes after injection (R = 0.64; P = 0.002). On contrast-enhanced MDCT, 5 minutes after injection, the signal-to-noise ratio was significantly higher than at 10 minutes after injection in LV blood (28 +/- 1 to 21 +/- 1, respectively; P = 0.0007), normal myocardium (18 +/- 1 to 15 +/- 1; P = 0.0009), and hyperenhanced infarcted myocardium (24 +/- 1 to 20 +/- 1; P = 0.004). MDCT image quality was significantly better at 5 minutes (3.2 +/- 0.1) than at 10 minutes (2.8 +/- 0.2, P = 0.01, kappa = 0.4). The DeltaHU ratio increased slightly but significantly between 5 minutes (0.83 +/- 0.01) and 10 minutes (0.93 +/- 0.01; P = 0.01), suggesting a slow wash-in and wash-out of contrast medium in infarcted myocardium. CONCLUSION: In ST segment elevation myocardial infarction patients contrast-enhanced MDCT is an accurate method for characterizing and sizing myocardial infarct and no-reflow. Contrast-enhanced MDCT performed 5 minutes after injection yields a higher signal-to-noise ratio and image quality than the 10 minutes time point with no difference in the extent of infarct measurement.