Determinants of renal tissue oxygenation as measured with BOLD-MRI in chronic kidney disease and hypertension in humans.

Experimentally renal tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD) and arterial hypertension (AHT). In this study we measured renal tissue oxygenation and its determinants in humans using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullary R2* values ( = 1/T2*) were calculated before and after administration of IV furosemide, a low R2* indicating a high tissue oxygenation. We studied 195 subjects (95 CKD, 58 treated AHT, and 42 healthy controls). Mean cortical R2 and medullary R2* were not significantly different between the groups at baseline. In stimulated conditions (furosemide injection), the decrease in R2* was significantly blunted in patients with CKD and AHT. In multivariate linear regression analyses, neither cortical nor medullary R2* were associated with eGFR or blood pressure, but cortical R2* correlated positively with male gender, blood glucose and uric acid levels. In conclusion, our data show that kidney oxygenation is tightly regulated in CKD and hypertensive patients at rest. However, the metabolic response to acute changes in sodium transport is altered in CKD and in AHT, despite preserved renal function in the latter group. This suggests the presence of early renal metabolic alterations in hypertension. The correlations between cortical R2* values, male gender, glycemia and uric acid levels suggest that these factors interfere with the regulation of renal tissue oxygenation.

The different types of internal hernia after laparoscopic Roux-En-Y gastric by-bass for morbid obesity : MDCT features : P5

Purpose: 1. To provide an overview of the different types of internal hernia (IH) occurring after laparoscopic Roux-en-Y gastric bypass (LRYGBP) performed for morbid obesity. 2. To describe the correspondent MDCT features in relation with the underlying anatomical landmarks in order to differentiate their localisation and to direct the surgeon during following laparoscopic closure of mesenteric defects. Methods and materials: LRYGBP performed for morbid obesity is associated with less perioperative complications, shorter hospital stay and a more rapid recovery compared with the open surgical procedure. However, a relatively high incidence of IH is seen that may be due to the laparoscopic approach, but also caused by rapid weight loss with consecutive loosening of the mesenteric sutures. Results: After briefly reviewing the surgical procedure of LRYGBP (ante- versus retrocolic) we describe the exact anatomical landmarks of the different types of IH occurring at any time after operation: They are caused by surgical defects either at the level of the transverse colon mesentery, at the Petersen's space, which represents an opening between the mesocolon and jejunal mesentery, or at the enteroenterostomy site. Typical MDCT features of each IH type in axial and coronal plane as well as targeted vascular reconstructions are demonstrated. Conclusion: Exact knowledge about underlying pathophysiology and anatomical landmarks is essential for distinguishing the different types of IH occurring after LRYGBP on MDCT, since radiological features are difficult to recognize and may even overlap. The radiologist should be aware of the potential anatomic sites to ensure subsequent straightforward laparoscopic exploration.

Successful treatment of trilateral retinoblastoma with conventional and high-dose chemotherapy plus radiotherapy: a case report.

Trilateral retinoblastoma (TRB) is a rare condition characterized by an intracranial neuroblastic tumor associated with bilateral or unilateral retinoblastoma (RB). The outcome is almost always fatal. An 18-month-old patient with familial bilateral RB was referred for a pineal lesion detected on a screening by magnetic resonance imaging. The child, considered inoperable by 2 different neurosurgical teams, was treated with conventional chemotherapy (methotrexate, vincristine, vepeside, cyclophosphamide, and carboplatin) plus tandem transplantation (vepeside/carboplatin and thiotepa/mephalan) followed by local radiotherapy. At 80 months from the diagnosis of TRB, the patient is alive and in complete remission, with no neuropsychologic consequences. An early and aggressive treatment may improve the prognosis of TRB.

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.

Choledocholithiasis: repetitive thick-slab single-shot projection magnetic resonance cholangiopancreaticography versus endoscopic ultrasonography.

This prospective study compares repetitive thick-slab single-shot projection magnetic resonance cholangiopancreatography (MRCP) with endoscopic ultrasonography (EUS) for the detection of choledocholithiasis. Fifty-seven consecutive patients (36 women, mean age 61) referred for suspected choledocholithiasis underwent MRCP, followed by EUS. Each procedure was performed by different operators blinded to the results of the other investigation. MR technique included a turbo spin-echo T2-weighted axial sequence with selective fat saturation (SPIR/TSE, TE=70 ms, TR=1,600 ms), followed by coronal dynamic MRCP. The same thick-slab slice was sequentially acquired 12 times as breath-hold single-shot projection imaging (SSh, TE=900 ms, TE=8,000 ms) centred on the common bile duct (CBD). Two experienced radiologists independently and blindly evaluated MR images for the detection of CBD stones. Their inter-observer agreement kappa was determined. Secondly, the two observers read MR images in consensus again. CBD stones were demonstrated in 18 out of 57 patients (31.6 %) and confirmed by endoscopic retrograde cholangiography (ERCP, n=17) or intraoperative cholangiography (n=1). Clinical follow-up served as the "gold standard" in patients with negative results without following invasive procedure (n=28). Sensitivity, specificity, accuracy, positive and negative predictive value for MRCP resulting from consensus reading were 94.9%, 94.4%, 94.7%, 97.4% and 89.5%, respectively. Corresponding values of EUS were 97.4%, 94.4%, 96.5%, 97.4% and 94.4%. Inter-observer agreement kappa was 0.81. Repetitive thick-slab single-shot projection MRCP is an accurate non-invasive imaging modality for suspected choledocholithiasis and should be increasingly used to select those patients who require a subsequent therapeutic procedure, namely ERCP.

Névrite vestibulaire: traitement et pronostic [Vestibular neuritis: treatment and prognosis].

Vestibular neuritis is a sudden unilateral peripheral vestibular deficit of unknown origin without associated hearing loss. It is the second cause of peripheral vertigo after Benign Paroxysmal Positional Vertigo (BPPV). The etiology remains unclear and some treatments are still controversial. The prognosis is good. The differential diagnosis of the disease mainly includes an acute vertigo of central origin. This article summarizes the management and prognosis of vestibular neuritis.

Diagnostic approach to pupillary abnormalities.

PURPOSE OF REVIEW: This article presents an overview of the common and various kinds of pupillary disorders that can be encountered in an outpatient setting. RECENT FINDINGS: The dorsal midbrain is a site where lesions may produce either an afferent or an efferent pupillary defect. The classic pupillary syndrome secondary to a dorsal midbrain lesion is bilateral light-near dissociation. Another recognized deficit is bilateral mydriasis. Recent reports have documented unilateral mydriasis, unilateral light-near dissociation, and a relative afferent pupillary defect without visual loss in association with lesions of the dorsal midbrain. These are rare syndromes. SUMMARY: Careful history and examination can often identify and localize the pupillary disorder, as well as guide appropriate evaluation.

Direct magnetic resonance arthrography of the wrist with axial traction: A feasibility study to assess joint cartilage.

PURPOSE: To assess the impact of axial traction during acquisition of direct magnetic resonance (MR) arthrography of the wrist with regard to joint space width and amount of contrast material between the opposing cartilage surfaces. MATERIALS AND METHODS: Fifteen consecutive patients (12 male, mean age 38.1 years) were included in this Institutional Review Board-approved prospective study. Three-compartment wrist MR arthrographies were performed between October and December 2009 on a 3 T unit using a fat-suppressed T1-weighted isotropic high-resolution volumetric interpolated breathhold examination (VIBE) sequence in the coronal plane, with and without axial traction (3 kg). Two radiologists measured radiocarpal (radioscaphoid, radiolunate) and midcarpal (lunocapitate, hamatolunate) joint space widths, with and without traction, and assessed the amount of contrast material between the opposing cartilage surfaces using a three-point scale: 0 = absence, 1 = partial, 2 = complete. RESULTS: With traction, joint space width increased significantly at the radioscaphoid (Delta = 0.78 mm, P < 0.01), radiolunate (Delta = 0.18 mm, P < 0.01), and lunocapitate (Delta = 0.45 mm, P < 0.01) spaces, and both observers detected significantly more contrast material between the cartilage surfaces. At the hamatolunate space, the differences in joint space width (Delta = 0.14 mm, P = 0.54) and amount of contrast material were not significant. CONCLUSION: Direct wrist MR arthrography with axial traction of 3 kg increases joint space width at the radiocarpal and lunocapitate spaces, and prompts better coverage of the articular cartilage by the contrast material. J. Magn. Reson. Imaging 2011;. (c) 2011 Wiley-Liss, Inc.

The NLRP3 inflammasome promotes renal inflammation and contributes to CKD.

Inflammation significantly contributes to the progression of chronic kidney disease (CKD). Inflammasome-dependent cytokines, such as IL-1β and IL-18, play a role in CKD, but their regulation during renal injury is unknown. Here, we analyzed the processing of caspase-1, IL-1β, and IL-18 after unilateral ureteral obstruction (UUO) in mice, which suggested activation of the Nlrp3 inflammasome during renal injury. Compared with wild-type mice, Nlrp3(-/-) mice had less tubular injury, inflammation, and fibrosis after UUO, associated with a reduction in caspase-1 activation and maturation of IL-1β and IL-18; these data confirm that the Nlrp3 inflammasome upregulates these cytokines in the kidney during injury. Bone marrow chimeras revealed that Nlrp3 mediates the injurious/inflammatory processes in both hematopoietic and nonhematopoietic cellular compartments. In tissue from human renal biopsies, a wide variety of nondiabetic kidney diseases exhibited increased expression of NLRP3 mRNA, which correlated with renal function. Taken together, these results strongly support a role for NLRP3 in renal injury and identify the inflammasome as a possible therapeutic target in the treatment of patients with progressive CKD.

The different types of internal hernia after laparoscopic Roux-En-Y gastric by-pass for morbid obesity: MDCT features [C-419]

Learning Objectives: 1. To provide an overview of the different types of internal hernia (IH) occurring after laparoscopic Roux‑en‑Y gastric bypass (LRYGBP) for morbid obesity. 2. To describe correspondent MDCT features in relation with the underlying anatomical landmarks in order to differentiate their localisation and to direct the surgeon during following laparoscopic closure of mesenteric defects. Background: LRYGBP for morbid obesity is associated with less perioperative complications, shorter hospital stay and a more rapid recovery compared with the open surgical procedure. However, a relatively high incidence of IH is seen that may be due to the laparoscopic approach, but also caused by rapid weight loss with consecutive loosening of the mesenteric sutures. Procedure Details: After briefly reviewing the surgical procedure of LRYGBP (ante‑ versus retrocolic), we describe the exact anatomical landmarks of the different types of IH occurring at any time after operation: They are caused by surgical defects at the level of the transverse colon mesentery, at the Petersen's space, which represents an opening between the mesocolon and jejunal mesentery, or at the entero‑enterostomy site. Typical MDCT features of each IH type in axial and coronal planes as well as targeted vascular reconstructions are demonstrated. Conclusion: Exact knowledge about underlying pathophysiology and anatomical landmarks is essential for distinguishing the different types of IH occurring after LRYGBP on MDCT, since radiological features are difficult to recognize and may even overlap. The radiologist should be aware of the potential anatomic sites to ensure subsequent straightforward laparoscopic exploration.

Computed tomography angiography vs 3 T black-blood cardiovascular magnetic resonance for identification of symptomatic carotid plaques.

BACKGROUND: The purpose of this prospective study was to perform a head-to-head comparison of the two methods most frequently used for evaluation of carotid plaque characteristics: Multi-detector Computed Tomography Angiography (MDCTA) and black-blood 3 T-cardiovascular magnetic resonance (bb-CMR) with respect to their ability to identify symptomatic carotid plaques. METHODS: 22 stroke unit patients with unilateral symptomatic carotid disease and >50% stenosis by duplex ultrasound underwent MDCTA and bb-CMR (TOF, pre- and post-contrast fsT1w-, and fsT2w- sequences) within 15 days of symptom onset. Both symptomatic and contralateral asymptomatic sides were evaluated. By bb-CMR, plaque morphology, composition and prevalence of complicated AHA type VI lesions (AHA-LT6) were evaluated. By MDCTA, plaque type (non-calcified, mixed, calcified), plaque density in HU and presence of ulceration and/or thrombus were evaluated. Sensitivity (SE), specificity (SP), positive and negative predictive value (PPV, NPV) were calculated using a 2-by-2-table. RESULTS: To distinguish between symptomatic and asymptomatic plaques AHA-LT6 was the best CMR variable and presence / absence of plaque ulceration was the best CT variable, resulting in a SE, SP, PPV and NPV of 80%, 80%, 80% and 80% for AHA-LT6 as assessed by bb-CMR and 40%, 95%, 89% and 61% for plaque ulceration as assessed by MDCTA. The combined SE, SP, PPV and NPV of bb-CMR and MDCTA was 85%, 75%, 77% and 83%, respectively. CONCLUSIONS: Bb-CMR is superior to MDCTA at identifying symptomatic carotid plaques, while MDCTA offers high specificity at the cost of low sensitivity. Results were only slightly improved over bb-CMR alone when combining both techniques.

Familial aplasia of the trapezius muscle: clinical and MRI findings.

A 5-year-old boy was referred to our neurology clinic for suspected myopathy. His parents reported normal upper extremity strength and no limitation in daily activities; however, he was unable to raise his arms above his head. On examination, both shoulders were down-slanting and anteriorly displaced, leading to a webbed neck appearance. Muscle MRI demonstrated isolated bilateral aplasia of the trapezius muscles. His father was found to have a unilateral partial trapezius hypoplasia with no functional consequences. Conclusion:  Congenital aplasia of the trapezius muscle is a rare condition; bilateral aplasia of the muscle, having been reported in only five cases, is most often associated with aplasia of the pectoralis major. This is the first report to our knowledge to demonstrate bilateral isolated trapezius aplasia by MRI.

Inexperienced sonographers can successfully visualize and assess a three-dimensional image of the fetal face using a standardized ultrasound protocol

Introduction: A standardized three-dimensional ultrasonographic (3DUS) protocol is described that allows fetal face reconstruction. Ability to identify cleft lip with 3DUS using this protocol was assessed by operators with minimal 3DUS experience. Material and Methods: 260 stored volumes of fetal face were analyzed using a standardized protocol by operators with different levels of competence in 3DUS. The outcomes studied were: (1) the performance of post-processing 3D face volumes for the detection of facial clefts; (2) the ability of a resident with minimal 3DUS experience to reconstruct the acquired facial volumes, and (3) the time needed to reconstruct each plane to allow proper diagnosis of a cleft. Results: The three orthogonal planes of the fetal face (axial, sagittal and coronal) were adequately reconstructed with similar performance when acquired by a maternal-fetal medicine specialist or by residents with minimal experience (72 vs. 76%, p = 0.629). The learning curve for manipulation of 3DUS volumes of the fetal face corresponds to 30 cases and is independent of the operator's level of experience. Discussion: The learning curve for the standardized protocol we describe is short, even for inexperienced sonographers. This technique might decrease the length of anatomy ultrasounds and improve the ability to visualize fetal face anomalies.

Outcome of long-axis percutaneous sacroplasty as first-line treatment of sacral insufficiency fractures : P219

Purpose: To assess the clinical outcome of patients who were subjected to long-axis sacroplasty as first line treatment for sacral insufficiency fractures. Methods and materials: Nineteen patients with unilateral (n = 3) or bilateral (n = 16) sacral fractures were involved. Under local anaesthesia, each patient was subjected to CT guided sacroplasty using the long-axis approach through a single entry point. An average of 6 ml of PMMA was delivered along the path of each sacral fracture. For each individual patient, the VAS pain score before sacroplasty and at 1, 4, 24, and 48 weeks after the procedure was obtained. Furthermore, the use of analgesics (narcotic/non-narcotic) along with the evolution of post interventional patient mobility before and after sacroplasty was also recorded. Results: The mean pre-procedure VAS score was 8 ± 1.9. This has rapidly declined in the first week after the procedure (mean 4 ± 1.5) followed by gradual decrease along the rest of follow-up period at 4 weeks (mean 3 ± 1.2), 24 weeks (mean 2 ± 1.3), and 48 weeks (mean 1.3 ± 1.4), respectively. Eleven (58%) patients were under narcotic analgesia before sacroplasty, whereas, 8 (42%) patients were using non-narcotics. Corresponding values after the procedure were 2/19 (10%) (narcotic) and 10/19 53% (non-narcotic). Seven (37%) patients did not address post-procedure analgesic use. The evolution of post interventional mobility was favourable in the study group since they revealed a significant improvement in their mobility point scale. Conclusion: Long-axis percutaneous sacroplasty is a suitable minimally invasive treatment option for patients who present with sacral insufficiency fractures. Future studies with larger patient number are warranted to grasp any potential limitations of this therapeutic approach.

Acquired and Congenital Ocular Toxoplasmosis Experimentally Induced in Calomys callosus (Rodentia, Cricetidae)

An experimental model for acquired and congenital ocular toxoplasmosis as well as a model to induce experimental autoimmune uveitis (EAU) was investigated in Calomys callosus. Toxoplasma gondii, ME-49 strain, was used to infect males and pregnant- and not pregnant-females while S-antigen, a major glycoprotein of the retinal photoreceptor cell, was used to induce EAU. The ocular lesions elicited by T. gondii were characterized by the presence of cysts, free tachyzoites and inflammatory cells in the retina or related tissues. In the congenital form, 40% of the fetus presented ocular lesions, i.e., presence of cysts in the retina, vitreous, and extra-retinal tissues. In the acquired form, 75% of the females and 50% of the males presented unilateral ocular cysts both at 21 and 47 days post-infection. It was also demonstrated that S-antigen was not uveitogenic in the C. callosus model. No lesion was observed in the animals exclusively immunized with this retinal component, even when jacalin was used as additional adjuvant for polyclonal response to the retinal antigen. It can be concluded that C. callosus may constitute in a promising model for study both acquired and congenital ocular toxoplasmosis, particularly when it is important to make sure that a non autoimmune process is involved in the genesis of the ocular infection.