Circulation and suspended sediment transport in a coral reef lagoon: the south-west lagoon of New Caledonia.

The south-west lagoon of New Caledonia is a wide semi-open coral reef lagoon bounded by an intertidal barrier reef and bisected by numerous deep inlets. This paper synthesizes findings from the 2000-2008 French National Program EC2CO-PNEC relative to the circulation and the transport of suspended particles in this lagoon. Numerical model development (hydrodynamic, fine suspended sediment transport, wind-wave, small-scale atmospheric circulation) allowed the determination of circulation patterns in the lagoon and the charting of residence time, the later of which has been recently used in a series of ecological studies. Topical studies based on field measurements permitted the parameterisation of wave set-up induced by the swell breaking on the reef barrier and the validation of a wind-wave model in a fetch-limited environment. The analysis of spatial and temporal variability of suspended matter concentration over short and long time-scales, the measurement of grain size distribution and the density of suspended matter (1.27 kg l(-1)), and the estimation of erodibility of heterogeneous (sand/mud, terrigenous/biogenic) soft bottoms was also conducted. Aggregates were shown to be more abundant near or around reefs and a possible biological influence on this aggregation is discussed. Optical measurements enabled the quantification of suspended matter either in situ (monochromatic measurements) or remotely (surface spectral measurements and satellite observations) and provided indirect calibration and validation of a suspended sediment transport model. The processes that warrant further investigation in order to improve our knowledge of circulation and suspended sediment transport in the New Caledonia lagoon as well as in other coral reef areas are discussed, as are the relevance and reliability of the numerical models for this endeavour.

[Magnetic resonance imaging of medial meniscus tears with displaced fragment in the meniscal recesses]. / Diagnostic IRM des lambeaux méniscaux médiaux déplacés le long du ligament tibial collatéral.

PURPOSE OF THE STUDY: Displaced meniscus tears generally result from bucket handle tears with subsequent migration of the meniscal fragment into the intercondylar notch. More rarely, the fragment may move into the meniscal recesses. In this situation, the displaced fragment may be difficult to individualize arthroscopically, so preoperative imaging is crucial. Several studies have demonstrated the reliability of magnetic resonance imaging (MRI) for the diagnosis of meniscus injury with fragment displacement in the intercondylar notch. There have been few studies devoted to fragment displacement into the collateral capsuloligamentary structures. The purpose of this study was to describe MRI findings of medial meniscus tears with displaced fragment in the meniscal recesses. MATERIAL AND METHODS: This prospective study was conducted over a 22-month period (May 2003 - February 2005). During this period, we selected 39 patients whose knee MRI displayed a meniscal fragment within the medial collateral recesses. These 39 patients accounted for 15% of knees with MRI-diagnosed meniscal tears (n=272) and 2% of the knee MRI examinations performed during the study period (n=2239). One the MRI series, we studied fragment migration and morphological anomalies of the injured meniscus. For 16 knees, MRI findings could be compared with arthroscopy findings. RESULTS: For 25 knees (65%), the meniscal fragment had migrated downward along the medial tibial plateau and generally (64%) medially to the collateral tibial ligament. For 14 knees (35%) the meniscal fragment had migrated upward, along the medial femoral condyle in 93%, anteriorly to the medial collateral tibial ligament. For 95%, the MRI demonstrated rupture along the free border of the posterior segment and/or the mid segment of the medial meniscus or a decreased height of the posterior segment of the medial meniscus. For 14 of 16 cases, arthroscopy confirmed the meniscal tear and the localization of the displaced fragment. For two knees, arthroscopy confirmed the presence of the meniscal tear but could not identify the displaced meniscal fragment. DISCUSSION: Meniscal tears with fragment displacement into the meniscal recesses has been associated with displacement of a horizontal fissuration which flap tears described arthroscopically by DJ Dandy. Other authors consider these tear flaps as oblique fissurations. In our study, it was sometimes difficult to determine the exact site and orientation of the initial meniscal tear so it is quite likely that meniscal tears with a displaced fragment in the meniscal recesses could correspond to complex predominantly horizontal or oblique meniscal fissurations. The common feature is the presence of an unstable meniscal flap susceptible to migrate. Our findings are in agreement with the literature. Regarding the two cases where the MRI findings could not be confirmed arthroscopically, the MRI visualized a characteristic image of a meniscal fragment displaced downwardly, lying between the medial tibial plateau and the collateral tibial ligament. Arthroscopy visualized the meniscal tear but failed to visualize the displaced fragment. This might be because mobile meniscal fragments return into the joint interspace when the meniscus is manipulated arthroscopically. Small meniscal fragments might also be inaccessible arthroscopically.

[Reactive synovitis: MRI features with arthroscopic correlation]. / Synovites réactionnelles: aspects en IRM et corrélations arthroscopiques.

OBJECTIVES: To evaluate MR imaging in detecting and characterizing secondary reactive synovitis and correlate the results with arthroscopy. MATERIALS AND METHODS: Retrospective study of 10 patients referred for MR imaging and arthroscopy of the knee or shoulder. The diagnosis of reactive synovitis was confirmed by arthroscopy and pathological examination. Synovial thickening was graded at MRI as follows. Grade 0: normal; grade 1: diffuse synovial thickening; grade 2: nodular synovial hypertrophy; grade 3: pseudotumoral synovial mass. RESULTS: Synovitis was described at MRI in 8 cases. There were 2 false negative results on MR imaging for the knee. Synovitis was secondary to knee trauma and rotator cuff tear or surgery of the shoulder. On arthroscopy, all synovial lesions were detected and confirmed at pathology. Synovitis was not detected at MRI (grade 0) in 20% of cases. Synovitis appeared diffuse (grade 1) in 30%, nodular (grade 2) in 30% and pseudotumoral (grade 3) in 20%. Bony erosions were adjacent to synovial thickening in 5 cases. CONCLUSION: Reactive synovitis can occur after trauma. MR imaging is useful in detecting and evaluating secondary reactive synovitis. Arthroscopy and synovial biopsy are necessary to exclude infectious or tumoral synovitis.

[Interventional lumbar spine radiology]. / Radiologie interventionnelle du rachis lombaire.

Three different techniques will be discussed. The first procedure is the biopsy of the lumbar vertebra or lumbar intervertebral disc for patients with tumors or infections of the lumbar spine. The different needles that can be used in function of consistency and location of the lesion will be shown. The transpedicular and posterolateral techniques will be described. Cementoplasty for tumors and selected patients with osteoporotic vertebral collapse generates much interest. The transpedicular and posterolateral techniques will be described. Indications and complications, more frequent in patients with tumors, will be reviewed. Finally, foraminal injections of steroids in patients with radicular symptoms secondary to degenerative change will be discussed. Techniques for needle placement will be reviewed. Results from these injections will also be reviewed.

[Radiological spectrum of myositis ossificans circumscripta evolution]. / Spectre radiologique évolutif de la myosite ossifiante circonscrite.

Myositis ossificans circumscripta is a benign pathology of soft tissue occurring in young patients often after localized trauma. Histological and radiological appearances may mimic a malignant neoplasm, mainly sarcoma. We report a case characteristic of myositis ossificans circumscripta, to illustrate diagnostic arguments which are based on their appearance on conventional radiographs, computed tomography and magnetic resonance imaging and on their changes with time.

[D-Dimer determination combined with clinical probability for the diagnosis of leg venous thrombosis]. / Association en pratique clinique du dosage des D-Dimères et d'une probabilité clinique pour le diagnostic de thrombose veineuse des membres inférieurs.

OBJECTIVE: To evaluate the results of combination of D-Dimer test and simple clinical model for the diagnosis of deep vein thrombosis (DVT). MATERIALS AND METHODS: Inclusion: clinical suspicion of DVT. Non inclusion criteria were Clinical model performed by the referring physician included probability varying from high to low. D-Dimer test was performed by five different rapid techniques. Standard of reference was Doppler ultrasonography (DU) performed by a senior radiologist. RESULTS: Eight hundred and fifty-four DU were performed on a 14 months time period, including 206 suspicion of pulmonary embolism, 109 postoperative time period, 120 non-included or excluded patients, 278 incomplete observations, 141 complete observations. DVT was present in 33 cases and absent in the other 108 cases (prevalence 23%). Sensitivity and negative predictive value of the five tests were between 82 and 97% and 90 et 97%. The most sensitive test had a specificity of 36% and a positive predictive value of 32%. Combination of clinical model and D-Dimer test did not improve the diagnostic accuracy. CONCLUSION: None of the test evaluated in the present study, even when combined with the clinical model results, did allow the exclusion of DVT.

[MRI appearance of a primary leiomyosarcoma of bone with epiphyseal involvement]. / Aspect IRM d'un cas de léiomyosarcome osseux primitif de localisation épiphysaire.

Primary leiomyosarcoma of bone is a rarely reported tumor of elderly subjects. It usually shows an aggressive osteolytic pattern on plain radiographs and involves predominantly the metaphyses of long bones. We report a case of primary leiomyosarcoma of bone, which is atypical by its epiphyseal location, a non-aggressive pattern on plain radiographs and its MR imaging features.

[Adductor muscle pyomyositis simulating acute appendicitis: CT and MR imaging findings]. / Pyomyosite des muscles adducteurs mimant une appendicite aiguë: aspects tomodensitométriques et irm.

Pyomyositis is a primary bacterial infection of skeletal muscle. This infection tends to occur in the large muscles of the lower extremity. Pyomyositis of the proximal muscles of the thigh can simulate acute abdominal disease. Early diagnosis improves the outcome. Delayed diagnosis may lead to septicemia and shock. We report the CT and MRI findings in a patient with pyomyositis of the proximal muscles of the thigh.

A scale of methodological quality for clinical studies of radiologic examinations.

PURPOSE: To develop and evaluate a scale for assessment of the methodological quality for clinical investigations of radiologic studies. MATERIALS AND METHODS: A scale was developed that included methodological standards compiled from established sources for assessing the methodological quality of study designs in clinical research and characteristics related to biases commonly observed in clinical radiologic research. The scale was composed of 15 standards and was tested with the results of 96 studies on imaging of liver hemangioma. Interrater reliability was measured between two observers by using percentage agreement and kappa statistics. Interrater reliability between two observers for a composite quality index that encompassed the 15 standards was measured with the intraclass correlation coefficient. RESULTS: Agreement between the two observers was almost perfect (kappa value, 0.8-1.0) for 11 standards and substantial (kappa value, 0.74-0.78) for four standards. Agreement between the observers with regard to the composite quality index also was high (intraclass correlation coefficient r, 0.91 [95% CI: 0.87, 0.94]). CONCLUSION: The scale appears to be reliable for the assessment of methodological quality of clinical investigations of radiologic studies.

[Hajdu-Cheney syndrome: an unusual cause of acro-osteolysis]. / Le syndrome d'Hajdu-Cheney: une cause rare d'acro-ostéolyse.

We report a case of Hajdu-Cheney syndrome. This cranioskeletal dysplasia is characterized by band-like acro-osteolysis of the tufts middle thirds. Differential diagnosis of band-like acro-osteolysis are discussed.

Hyperextension vertebral body fractures in diffuse idiopathic skeletal hyperostosis: a cause of intravertebral fluidlike collections on MR imaging.

OBJECTIVE: We describe an intravertebral fluidlike collection observed on MR images in five of six patients who sustained vertebral body fracture through a segment of the spine ankylosed by diffuse idiopathic skeletal hyperostosis. The mechanism of injury, clinical course, conventional radiographs, CT scans, and other MR imaging findings are analyzed. CONCLUSION: Intravertebral fluidlike collections were associated with hyperextension injury of the spine. Well-delineated borders, anterior widening, and associated posterior-element injury are the main MR imaging characteristics of this trauma-related intravertebral fluidlike collection.

Symptomatic lumbar facet joint synovial cysts: clinical assessment of facet joint steroid injection after 1 and 6 months and long-term follow-up in 30 patients.

PURPOSE: To study the results of facet joint intraarticular steroid injections in patients with symptomatic lumbar facet joint synovial cysts. MATERIALS AND METHODS: Data from 30 patients (age range, 44-82 years; mean age, 67 years) with nerve root pain due to a lumbar facet joint synovial cyst and treated with facet joint steroid injection were retrospectively studied. On the basis of MacNab criteria, the clinical course of nerve root pain was evaluated after 1 (n = 30) and 6 (n = 28) months. Data from long-term follow-up (mean, 26 months) were also available in 14 nonsurgically treated patients. RESULTS: After 1 month, the nerve root pain outcome was excellent or good in 20 patients (67%) and fair or poor in 10 (33%). After 6 months, 10 (50%) of these 20 patients still had excellent or good results, and 18 (60%) of the 30 patients had a fair or poor clinical status, 14 of whom underwent surgery; two patients (7%) were lost to follow-up. Excellent and good results were maintained at further follow-up (range, 9-50 months). CONCLUSION: One-third of patients with symptomatic lumbar facet joint synovial cysts had long-lasting acceptable benefit from facet joint steroid injections in this study. Steroid injection should be indicated before surgery.

Rhinoscleroma with orbital extension: CT and MRI.

We describe the MRI features of a rhinoscleroma with orbital extension. This benign bacterial and granulomatous lesion of the paranasal sinuses gave homogeneous low intensity on T2-weighted images and enhanced with gadolinium. It could simulate a malignant sinonasal tumour or a fungal sinusitis; the diagnosis must be considered in patients from endemic areas.