Verification of computed tomographic estimates of cochlear implant array position: A micro-CT and histological analysis

We examine the efficacy two volume spatial registration of pre and postoperative clinical computed tomography (CT) imaging to verify post-operative electrode array placement in cochlear implant (CI) patients. To measure the degree of accuracy with which the composite image predicts in-vivo placement of the array, we replicate the CI surgical process in cadaver heads. Pre-operative, post-operative, micro CT imaging and histology are utilized for verification.

Research practices that can prevent an inflation of false-positive rates

Recent studies have indicated that research practices in psychology may be susceptible to factors that increase false-positive rates, raising concerns about the possible prevalence of false-positive findings. The present article discusses several practices that may run counter to the inflation of false-positive rates. Taking these practices into account would lead to a more balanced view on the false-positive issue. Specifically, we argue that an inflation of false-positive rates would diminish, sometimes to a substantial degree, when researchers (a) have explicit a priori theoretical hypotheses, (b) include multiple replication studies in a single paper, and (c) collect additional data based on observed results. We report findings from simulation studies and statistical evidence that support these arguments. Being aware of these preventive factors allows researchers not to overestimate the pervasiveness of false-positives in psychology and to gauge the susceptibility of a paper to possible false-positives in practical and fair ways.

False-positive results of a rapid K39-based strip test and Chagas disease

Background: The definitive diagnosis of visceral. leishmaniasis (VL) requires invasive procedures with demonstration of amastigotes in tissue or promastigotes in culture. Unfortunately, these approaches require laboratory materials not available in poor countries where the disease is endemic. The correct diagnosis of VL is important, and made more difficult by the fact that several common tropical diseases such as malaria, disseminated tuberculosis, and enteric fever share the same clinical presentation. Serological tests have been developed to replace parasitological diagnosis in the field. A commercially available K39-based strip test for VL has been developed for this purpose. The endemic area of leishmaniasis in Brazil overlaps the endemic area of Chagas disease, a disease that can cause false-positive serological test results. The aim of this study was to evaluate the incidence of false-positive exams using a rapid test for VL in patients with Chagas disease. Methods: A rapid test based on the recombinant K39 antigen of Leishmania was used in: (1) 30 patients with confirmed Chagas disease, (2) 30 patients with a serological diagnosis of Chagas disease by ELISA, indirect immunofluorescence, indirect hemagglutination, and chemiluminescence, (3) 30 healthy patients from a non-endemic area as the control group, (4) 30 patients with confirmed VL, and (5) 20 patients with proved cutaneous leishmaniasis. Results: The sensitivity and specificity of the rapid strip test were 100% when compared with healthy volunteers and those with confirmed Chagas disease. One false-positive result occurred in the group with Chagas disease diagnosed by serological tests (specificity of 96%). Conclusion: The rapid test based on recombinant K39 is a useful diagnostic assay, and a false-positive result rarely occurs in patients with a serological diagnosis of Chagas disease. (C) 2008 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Ultrasonographic, computed tomographic, and operative findings in dogs infested with giant kidney worms (Dioctophyme renale)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cerebellar tomographic attenuation of healthy felines

The cerebellum is responsible for coordination and maintenance of the fine control of muscle contraction. In cases of a suspected cerebellar disorder, a computed tomography scan can be performed to identify structural change. The aim of this study is to describe the cerebellar tomographic attenuation values in healthy cats since this variable is considered of great importance in the evaluation of images obtained by this imaging modality. A simple and a contrast enhanced brain computed tomographic scan were performed in 15 adult cats with no history of neurological symptoms and negative for feline leukemia and immunodeficiency virus. After acquiring the image, the measurement of the average attenuation of a cerebellar area of 2 centimeters in diameter was obtained. The cerebellar tomographic attenuation showed a variation from 14.60 to 25.50 HU in the simple scan and from 25.50 to 33.40 HU in the enhanced phase. Most animals (73.33%) had precontrast cerebellar attenuation values within the stipulated limit for the brain in a previous study (20-41 HU). Four animals in this study (26.67%) had values lower than 20 HU, which can be explained by differences in cellular composition between these two regions. The average value of contrast enhancement was 4.91 HU, and in none of the animals an enhancement greater than 10 HU was observed, which is in agreement with previous studies.

Computed tomographic dacryocystography in children undergoing balloon dacryoplasty

PURPOSE To ascertain whether the volume and circumference of the lacrimal sac and nasolacrimal duct as measured by contrast-enhanced computed tomographic dacryocystography (CT-DCG) before and after balloon dacryoplasty could be used to predict clinical success in children with congenital nasolacrimal obstruction. METHODS Nasolacrimal ducts of children aged 2 to 6 years with clinical signs of congenital nasolacrimal duct obstruction undergoing balloon dilation were imaged with contrast-enhanced CT-DCG before and 5 minutes after the procedure. The circumference of the most dilated portion of the lacrimal sac was measured on the axial plane. The volume of contrast within the nasolacrimal duct and sac was also measured before and after the procedure. Clinical success was defined as the disappearance of signs of epiphora. RESULTS A total of 18 nasolacrimal ducts of 13 children were included. The average circumference of the most dilated portion of the lacrimal sac was 1.30 +/- 0.45 cm (range, 0.64-2.50 cm) before the procedure. The average contrast volume was 0.12 +/- 0.08 cm(3) (range, 0.01-0.38 cm(3)) before and 0.07 +/- 0.06 cm(3) (range, 0.01-0.20 cm(3)) after (P = 0.01). Data were analyzed using multivariate logistic regression with a backward variable input model; a decrease in contrast volume before and after dilation (P = 0.04) was associated with clinical success, whereas the larger size of the most dilated portion of the lacrimal sac (P = 0.01) was associated with clinical failure. CONCLUSIONS Contrast-enhanced CT-DCG provides useful information about nasolacrimal anatomy in children with congenital nasolacrimal duct obstruction. The decrease in contrast volume before and after balloon dilation was predictive of success; A larger size of the most dilated portion of the lacrimal sac was associated with clinical failure. (J AAPOS 2012;16:464-467)

Cone Beam Computed Tomographic Imaging: Perspective, Challenges, and the Impact of Near-Trend Future Applications

Cone beam computed tomography (CBCT) can be considered as a valuable imaging modality for improving diagnosis and treatment planning to achieve true guidance for several craniofacial surgical interventions. A new concept and perspective in medical informatics is the highlight discussion about the new imaging interactive workflow. The aim of this article was to present, in a short literature review, the usefulness of CBCT technology as an important alternative imaging modality, highlighting current practices and near-term future applications in cutting-edge thought-provoking perspectives for craniofacial surgical assessment. This article explains the state of the art of CBCT improvements, medical workstation, and perspectives of the dedicated unique hardware and software, which can be used from the CBCT source. In conclusion, CBCT technology is developing rapidly, and many advances are on the horizon. Further progress in medical workstations, engineering capabilities, and improvement in independent software-some open source-should be attempted with this new imaging method. The perspectives, challenges, and pitfalls in CBCT will be delineated and evaluated along with the technological developments.

Cone Beam Computed Tomographic Evaluation of a Maxillary Alveolar Ridge Reconstruction With Iliac Crest Graft and Implants

The present article discusses an atrophic maxilla reconstruction with iliac crest bone block and particulate grafts and dental implants. Onlay block grafts were used to restore bone volume of the anterior maxilla, whereas bilateral sinus floor augmentation was performed using a particulate graft. Ten months after the grafting surgery, 9 dental implants were placed to rehabilitate the case. Results of a 7-year follow-up were obtained clinically and by cone beam computed tomographic images.

Maxillary sinus and posterior teeth: accessing close relationship by cone-beam computed tomographic scanning in a brazilian population

Introduction: This study aimed to evaluate the close proximity established between the maxillary sinus floor and posterior teeth roots apices by using cone-beam computed tomographic scanning. Methods: The relationship of maxillary sinuses and posterior teeth roots, which were divided into 2 groups, was analyzed using i-CAT Vision software (Imaging Sciences, Hatfield, PA). Group 1 included all root apices found in close contact with the maxillary sinus floor without sinus floor elevation, whereas group 2 included all root apices that were protruded within the sinus producing an elevation of the bony cortical. Results: A total of 100 maxillary sinuses and 601 roots apices were evaluated. Group 1 presented 130 of 601 (21.6%) roots and group 2 presented 86 of 601 (14.3%) roots. Conclusions: The second molar mesiobuccal root apex is frequently found in close proximity with the sinus floor, and the relation between these anatomic structures should be considered in order to prevent an iatrogenic procedure and minimize the risks from an infectious disease within the sinus

Spontaneous combined rupture of a pelvicalyceal cyst into the collector system and retroperitoneal space during the acquisition of computed tomography scan images: a case report

Abstract Introduction Pelvicalyceal cysts are common findings in autopsies and can manifest with a variety of patterns. These cystic lesions are usually a benign entity with no clinical significance unless they enlarge enough to cause compression of the adjacent collecting system and consequently obstructive uropathy. Few cases of the spontaneous rupture of pelvicalyceal renal cysts have been published and to the best of our knowledge there is no report of a combined rupture to collector system and retroperitoneal space documented during a multiphase computed tomography. Case presentation We report a case of a ‘real-time’ spontaneous rupture of a pelvicalyceal cyst into the collecting system with fistulization into the retroperitoneum. The patient was a 78-year-old Caucasian man with a previous history of renal stones and a large pelvicalyceal renal cyst who was admitted to our Emergency department with acute right flank pain. A multiphase computed tomography was performed and the pre-contrast images demonstrated a right pelvicalyceal renal cyst measuring 12.0 × 6.1cm in the lower pole causing moderate dilation of the upper right renal collection system. In addition, a partially obstructive stone on the left distal ureter with mild left hydronephrosis was noted. The nephrographic phase did not add any new information. The excretory phase (10-minute delay) demonstrated a spontaneous rupture of the cyst into the pelvicalyceal system with posterior fistulization into the retroperitoneal space. Conclusion In this case study we present time-related changes of a rare pelvicalyceal cyst complication, which to the best of our knowledge has fortunately not been previously documented. Analysis of the sequential images and comparison with an earlier scan allowed us to better understand the physiopathological process of the rupture, the clinical presentation and to elaborate hypotheses for its etiopathogenesis.

Huge ruptured and infected pseudoaneurysm of the ascending aorta and aortic arch with erosion of sternum after previous cardiac surgery

A 77-year-old woman underwent aortic valve replacement and coronary bypass grafting in 2007 in the Emirates. Evolution was uneventful until December 2011. After repeated episodes of unspecific infections, a computed tomographic scan showed a large pseudoaneurysm of the distal ascending aorta. The site of aortic rupture was closed with a Gore-Tex patch and a Staphylococcus aureus infection treated appropriately. Two months later, a small cutaneous lesion on the cranial part of the sternotomy started bleeding. Computed tomographic scan demonstrated recurrence of a false aneurysm with erosion of the sternum and a large subcutaneous hematoma caused by the fistula. The patient was transferred to our institution. The challenges of this case included safe surgical approach (sternotomy, cannulation, perfusion, cerebral protection) as well as complete removal and extensive debridement of the infected material and reconstruction of the aortic arch. Using fully biological material, reconstruction of the ascending aorta and proximal arch was successfully performed.