1,720,988 research outputs found
MRI of Paraspinal Gossypiboma: Look for the Barium Sulfate Filament
No full textGossypiboma is a rare post-surgical complication comprising a retained surgical gauze surrounded by a foreign body reaction. Although usually presenting on magnetic resonance imaging (MRI) with low T1 signal, high central and low peripheral signal on T2, and bandlike peripheral enhancement, MR appearance is often non-specific. The barium sulphate filament within a surgical gauze presents on MR as a curvilinear thread which is dark on both T1 and T2 sequences. Scrutinizing the MR images is critical to identify the filament and to pinpoint the diagnosis of gossypiboma. Teaching Point: A paraspinal mass on postoperative spine MRI should be carefully searched for a hypointense contorted wire (the barium sulfate filament), as it may be the characteristic finding to evocate the diagnosis of gossypiboma
Neuritis ossificans mimicking a malignancy in a child: case report and literature review
No full textWe present the case of a child with neuritis ossificans after acute trauma, treated conservatively. The aim of the review is to compare several parameters in this disease. Emphasis is placed on the clinical-radiological features distinguishing neuritis ossificans from malignancy to avoid unnecessary biopsy and surgery.A literature review was performed. Only 18 cases were described. Except for one, all describe adults, and none had acute trauma. Nearly all were treated surgically.Our 13-year-old patient presented with posterior knee pain after trauma. MRI demonstrated a mass within the tibial nerve with oedema, some lymph nodes and increased avidity on 18fluoro-2-deoxyglucose-positron emission tomography. These findings can be reactive but also associated with malignancy. However, eggshell-like calcifications in the periphery of the mass were seen on CT. Biopsy and resection were proposed. Follow-up visits over the next weeks showed remarkable clinical improvement. Wait-and-scan was advised after international discussion. Follow-up imaging after 2 months showed resolution of the oedema and volume reduction of the mass, suggesting a benign pathology. Diagnosis of neuritis ossificans was proposed based on the clinical and radiological features. There was a favorable course with no complaints after two months. Imaging after seven months showed an almost complete regression.Neuritis ossificans should be considered within a painfull (mono)neuropathy. The initial inflammatory phase may mimic malignancy, misleading clinicians toward biopsy or surgery with the risk of nerve damage. As seen in our case, neuritis ossificans can be a self-limiting process. Therefore, conservative therapy should be considered with a wait-and-scan approach
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Chest CT Diagnosis of COVID-19: Accuracy using CO-RADS and CT-Involvement Scoring
No full textObjectives: Both Reporting and Data System (CO-RADS) and CT-involvement scores (CTIS) have been proposed for evaluation of COVID-19 on chest CT. The purpose of this single-center, retrospective study was to evaluate both scoring systems to diagnose COVID-19 infection in a high-prevalence area. Materials and Methods: Chest CT datasets (n = 200) and available reverse transcription polymerase chain reaction (RT-PCR) on nasopharyngeal swab were included. CT scans were assigned to four 'imaging groups' after scoring for both CO-RADS and CTIS. Diagnostic accuracy of chest CT was calculated respectively using RT-PCR and clinical diagnosis as gold standards: False-negatives and false-positives of chest CT regarding RT-PCR were studied in more depth using the medical files. Results: The 'imaging group' including CO-RADS 4/5 scores reached the highest diagnostic values for COVID-19 considering either the initial RT-PCR or the final clinical diagnosis as the standard of reference: accuracies of 172/200 (86%) to 181/200 (90.5%), sensitivities of 60/80 (88.2%) to 70/79 (88.6%), specificities of 112/132 (84.9%) to 111/121 (91.7%), negative predictive values (NPV) of 112/120 (93.3%) to 111/120 (92.5%), respectively. False-negative CTs regarding RT-PCR were mainly explained by imaging very early in the disease course (5 out of 8 cases) or COVID-19 infection with no/minor respiratory symptoms (3 out of 8 cases). Conclusion: Assessing chest CT using CO-RADS is a valuable diagnostic approach for COVID-19 infection in a high-prevalence area, with a higher accuracy than CTIS
High risk of tunnel convergence during combined anterior cruciate ligament and anterolateral ligament reconstruction.
No full textPurpose
To assess the risk of femoral tunnel convergence in combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstructions. The hypothesis was that a more proximal and anterior orientation of the ALL femoral tunnel should reduce the risk of convergence with the ACL femoral tunnel.
Methods
Fifteen fresh-frozen cadaver knees were examined. An anatomic ACL femoral tunnel was drilled arthroscopically in each specimen and ALL tunnels were made in two directions: 1) 0° coronal angulation and 20° axial angulation , 2) 30° coronal angulation and 30° axial angulation. Computed tomography scans were performed to investigate tunnel convergence and to measure the minimal distance between tunnels, tunnel length and the LFC width.
Results
Tunnel convergence occurred in 20 of 30 cases (67%). Convergence was significantly reduced when tunnels were drilled at 30° coronal and 30° axial angulation (P<0.05). The mean length of the ALL tunnel was 15.9mm (95% CI [13.6; 18.1]) and was independent of ALL tunnel angulation. The mean minimal distance between the ALL and ACL tunnel was 3.1 mm (95% CI [2.1; 4.1]). The odds ratio for tunnel convergence was 3.5 for small LFC, relative to large LFC (n.s.)
Conclusion
A high risk of tunnel convergence was observed when performing combined ACL and ALL reconstructions. The clinical relevance of this work is that the occurrence of tunnel conflicts can be reduced by aiming the ALL tunnel in a more proximal and anterior direction. Surgeons should be aware of this, since tunnel convergence could jeopardize the ACL reconstruction and fixation
Peroneal neuropathy after weight loss: a high-resolution ultrasonographic characterization of the common peroneal nerve
No full textThe objective of this study was to use in vivo ultrasonographic imaging to analyze the common peroneal nerve in controls and patients who were diagnosed with peroneal neuropathy (PN) due to significant weight loss. We also looked for a relationship between weight loss (magnitude) and the occurrence of PN. Fifty controls and six patients who were diagnosed with PN after losing a significant amount of weight were examined by means of ultrasonography (US). On the US images, the structure and reflectivity of the nerve were analyzed. Correlations were made between the ultrasonographic measurements and the body mass index (BMI) of controls. In PN patients, these ultrasonographic parameters were compared between the normal and pathological legs. BMI was positively correlated with the transverse cross-sectional area of the nerve and fibular tunnel in controls. In controls with a high BMI, the peroneal nerve appeared thicker and the US reflectivity of the nerve was higher. A lower US reflectivity was observed in the pathological legs of the six patients who developed PN after weight loss. The transverse cross-sectional area and reflectivity of the peroneal nerve on the US images could be viable tools in the diagnosis of PN after weight loss
FUNCTIONAL MAGNETIC RESONANCE IMAGING FOR PREOPERATIVE LOCALISATION OF ELOQUENT BRAIN AREAS RELATIVE TO BRAIN TUMOURS: CLINICAL IMPLEMENTATION IN A REGIONAL HOSPITAL
No full textThe purpose of this study was to evaluate the implementation of functional magnetic resonance imaging (fMRI) for clinical use in patients with a brain tumour in the setting of a regional hospital. Twenty-three patients underwent a fMRI examination as preoperative evaluation for a tumour adjacent to a eloquent brain area. The location and distance of the tumour relative to the fMRI activation area for this eloquent brain area was determined. Presence of postoperative neurological deficits was compared to the result of the fMRI examination. The fMRI examination was not interpretable in four of the twenty-three patients. In nine patients the eloquent brain area was located more than two centimetres from the tumour: seven showed no neurological deficit postoperatively, one patient experienced a temporary deficit, and one patient has not been operated yet. In the remaining ten patients the eloquent brain area was located less than two centimetres from the tumour: after (partial) resection of the tumour often using intra-operative cortical stimulation, six patients showed no neurological deficits, and three patients had temporary or permanent deficits. One patient was not operated. The clinical implementation of fMRI was successful in the preoperative evaluation of patients with a brain tumour and useful to plan the surgical intervention and to minimize postoperative neurological deficits
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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