Preoperative High-resolution Computed Tomography Research Articles

Can Preoperative High Resolution Computed Tomography Be Rationalized in Adult Cochlear Implant Candidates?

To establish whether criteria can be used to identify patients who do not need high resolution computed tomography (HRCT) scans before cochlear implant operations, by retrospectively applying a preoperative selection pathway, the Cambridge Cochlear Implant Protocol (CCIP). Retrospective case series. Tertiary referral center, Queen Elizabeth Hospital, Birmingham, UK (QEHB). One hundred adult patients receiving primary cochlear implantation (CI) operations from April 2015 to July 2016 performed at the QEHB who received preoperative HRCTs. Etiology of hearing loss and anatomical abnormalities were collected by reanalyzing HRCT scans. Patients were retrospectively grouped according to criteria to restrict HRCT use derived from the Cambridge Cochlear Implant Programme (CCIP). The two main outcomes, recorded management change and significant abnormalities, were compared between the two CCIP groups, scanned and not scanned. Twenty-six patients had significant abnormalities detected on imaging, 16 in the scanned group and 10 in the not scanned group (p = 0.152). Five patients had a recorded management change as a result of HRCT scan, four scanned group, one not scanned group (p = 0.107). Significant abnormalities and recorded management change were seen across all etiological subgroups of hearing loss. The anatomy within the temporal bone is variable amongst CI recipients. Recorded management change and significant abnormalities occurred in both CCIP groups and across many etiologies of hearing loss patients. No specific group, based on the etiology of their hearing loss could be identified that do not require preoperative HRCT. Therefore, it is recommended that all CI patients should continue to receive preoperative HRCT imaging.

Predictable prosthesis length on a high-resolution CT scan before a stapedotomy.

(1) To assess the correlation between preoperative high-resolution CT (HRCT) imaging measurement from the long process of the incus to the footplate and the length of intraoperative selected prosthesis. (2) To determine if HRCT has a predictive value of prolapsed facial nerve during stapedotomy. We evaluated in our tertiary care center, in a retrospective case series, 94 patients undergoing primary stapedotomy. Preoperative temporal bone HRCT scans were reformatted in the plane of the stapes to measure on the same section the distance between the long process of the incus and the footplate. Measurement was performed by otolaryngology resident and neurotologist. We analyze the interobserver correlation and the mean length measured on the HRCT to the selected prosthesis size intraoperatively. Mean HRCT measurement of the incus long process/footplate distance assessed by the otolaryngology resident and neurotologist was 4.34 and 4.38mm, respectively. Interobserver correlation was statistically significant [intraclass correlation coefficient (ICC) of 0.679 (p < 0.001)]. Mean selected prosthesis length intraoperatively was 4.36mm. Correlation between the mean selected length prosthesis and the mean HRCT measurement was also statistically significant [ICC of 0.791 (p < 0.001)]. Postoperatively, a statistical improvement was shown in air conduction (p < 0.001), bone conduction (p < 0.001) and air-bone gap reduction (p < 0.001). 2 cases of facial nerve covering one-half of the oval window were identified by HRCT and confirmed intraoperatively. HRCT is a valuable tool to predict preoperatively the length of the stapedotomy prosthesis. Moreover, it might be helpful to identify a potential prolapsed facial nerve, to confirm the diagnosis of otosclerosis and to rule out other abnormalities. Ultimately, it may optimize the stapedotomy procedure planning.

Revisiting Correlation Between Pre Operative High Resolution Computed Tomography and Operative Findings in Attico Antral Disease.

(1) To correlate the findings of high resolution computed tomography (HRCT) scans with operative findings in chronic otitis media (attico antral disease). (2) To assess the role of HRCT in chronic otitis media (attico antral disease). This prospective observational study undertaken at a tertiary level teaching hospital included 50 patients of chronic otitis media (attico antral disease) who underwent pre-operative HRCT scanning and the findings were compared with the operative findings and correlation between the two was assessed with appropriate statistical methods. HRCT findings correlated well for the status of malleus and incus, facial nerve canal, lateral semicircular canal, and sinus plate but were less accurate for stapes and tegmen plate. As for disease extent and prediction of cholesteatoma the degree of correlation was site dependent being greater in mastoid air cell system and epitympanum and lesser in mesotympanum and hypotympanum. HRCT despite of its value in management of chronic otitis media has its drawbacks and limitations. CT's accuracy of prediction in some aspects of the disease varies with the site of pathology and this point must always be kept in mind by the operating surgeon. We suggest that each health care centre should establish their own correlative indices for HRCT temporal bone imaging in COM. HRCT cannot be entirely relied upon in management of chronic otitis media patients. However against the backdrop of improved radiological skills in interpreting temporal bone ct images, improved CT machines and importantly the growing concern over medicolegal issues, the role of pre operative CT scan in COM is much more than what was thought previously. Undoubtedly, it is a very useful 'aid' to management BUT a well-trained, experienced and alert surgeon is the key for an accurate diagnosis and successful management of chronic otitis media (attico-antral disease).

Platform Session – Evoked potentials & NIOM: Percutaneous threshold of facial nerve stimulation predicts facial canal dehiscence

Iatrogenic facial nerve injury is one of the most feared complications of otologic surgery. While the incidence of facial nerve (FN) injury is low, dehiscence of the fallopian canal increases the FN’s vulnerability to accidental injury. High-resolution computed tomography (HRCT) of the temporal bone is used preoperatively to assess middle ear and mastoid anatomy; however, it is unreliable for detecting facial canal dehiscence. We aimed to determine if preoperative percutaneous FN stimulation could predict middle ear facial canal dehiscence. Between January 2015 and February 2017, we performed preoperative HRCT and percutaneous FN stimulation on adult patients who underwent otologic surgery at our institution. Stimulation was performed with a monopolar probe placed on the skin over the stylomastoid foramen and delivery of electrical stimuli ranged from 0 to 30 milliamperes (mA). Recordings were made from ipsilateral facial muscles and dependent variables included threshold to compound muscle action potential (CMAP), threshold to maximum amplitude of CMAP, and maximum amplitude of CMAP for each muscle. A retrospective chart review was performed and patients were included if they received both FN stimulation and HRCT. Sixty-nine patients met inclusion criteria. Of the 24 with an intraoperatively confirmed dehiscence, only 10 were identified by the attending surgeon on HRCT. Mean lowest threshold to CMAP (5.1 mA v. 9.1 mA), and mean threshold to CMAP (8.2 μV v. 11.8 μV) of dehiscent versus non-dehiscent nerves were significantly different (p < 0.05). As compared to patients with an intact fallopian canal, patients with dehiscent facial nerves have significantly lower mean threshold to evoke CMAPs with preoperative percutaneous FN stimulation. This test is a simple and cost-effective tool that can give the surgeon important preoperative information about facial nerve anatomy and potentially reduce the risk of iatrogenic injury during otologic surgery.

Quantitative evaluation of facial hypoplasia and airway obstruction in infants with syndromic craniosynostosis: relationship with skull base and splanchnocranium sutural pattern.

Craniosynostostic syndromes are due to multisuture synostoses and affect the entire craniofacial skeleton. This study analyzed the facial complex and airways to quantify the relationship between insufficient facial growth, airways obstruction, and the sutural pattern of the splanchnocranium and cranial fossae. Preoperative high-resolution CT images in 19 infants with syndromic craniosynostosis were quantitatively analyzed. Because all children showed involvement of minor sutures/synchondroses coursing in the posterior cranial fossa, they were divided into three groups according to the synostotic involvement of "minor" sutures/synchondroses coursing in anterior (ACF) and middle (MCF) cranial fossae: group 1 (ACF), group 2 (MCF), and group 3 (ACF-MCF). Analysis of the facial complex and airway was performed. Each group was compared with age-matched healthy subjects. Premature closure of skull base synchondroses of ACF and MCF was found only in groups MCF and ACF-MCF. Group MCF showed synostosis in the posterior branch of the coronal ring and reduced anterior hemifossae lengths while group ACF-MCF showed synostosis in the anterior branch of the coronal ring and reduced middle hemifossae lengths. No group showed reduced maxillary or mandibular volumes but group MCF showed synostosis of the zygomaticomaxillary sutures and maxillary retrusion. All groups showed reduced airway volume but group 2 had a higher degree of airway hypoplasia. The skull base synostotic process drives the changes in facial complex growth and airway obstruction. Premature closure of synchondroses/sutures in the posterior branch of the coronal ring causes insufficient facial growth, maxillary retrusion, and more severe airway reduction.

An evaluation of preoperative high resolution computed tomography of temporal bone in cholesteatoma

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; &lt;span lang="EN-IN"&gt;Cholesteatoma is relatively common and potentially dangerous disease of the ear. It is characterised by local destruction and osseous erosion leading to complications. High resolution computed tomography (HRCT) is the imaging modality of choice for evaluation of middle ear structures and pathology. The aim of this study is to evaluate role of preoperative HRCT in the diagnosis of the disease, its extension and complications and plan for surgery.&lt;/span&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; &lt;span lang="EN-IN"&gt;This prospective study was conducted at a tertiary referral teaching hospital and 40 cases of cholesteatoma were selected and their pre-operative HRCT temporal bone findings and intraoperative findings were correlated. &lt;/span&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; &lt;span lang="EN-IN"&gt;This study showed good correlation between preoperative HRCT findings of cholesteatoma, and intraoperative findings. &lt;/span&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; &lt;span lang="EN-IN"&gt;We conclude therefore the preoperative HRCT temporal bone is useful guide for the surgeon for the diagnosis and management of cholesteatoma.&lt;/span&gt;&lt;/p&gt;

Is HRCT Temporal Bone Necessary in All Cases of Active Squamous Chronic Otitis Media?

To assess the usefulness of high resolution computed tomography (HRCT) temporal bones in cases of active squamous chronic otitis media (COM). Comparison of HRCT findings with operative findings. A prospective study of 104 clinically diagnosed patients with COM were included. Each patient was subjected to full clinical evaluation and HRCT temporal bone was done. Preoperative HRCT finding were correlated with surgical findings. The sensitivity of HRCT temporal bone in detecting cholesteatoma was 91.81%. However it could not differentiate cholesteatoma from other soft tissue density like granulation or hypertrophic mucosa or discharge, but soft tissue attenuation content with bone erosion was considered as hallmark of cholesteatoma. The sensitivity and specificity of HRCT for detecting malleus, incus and stapes erosion was 71.5 and 88.5%, 86.3 and 95% and 53.1 and 64.7% respectively. The sensitivity and specificity for detecting erosion of lateral semicircular canal (LSCC) was 77.78 and 98.2%. The sensitivity and specificity for facial canal was 80 and 100%. HRCT gives excellent details about the extent of cholesteatoma with reasonable accuracy in expert hands. It helps to warn the surgeon about anatomical variations preoperatively and detects complications if any. It effectively depicts integrity or erosion of dural plate, sinus plate, LSCC, facial nerve. Malleus and incus are seen reasonably well but status of stapes are not recorded effectively.

Semiautomated Middle Ear Volume Measurement as a Predictor of Postsurgical Outcomes for Congenital Aural Atresia.

Middle ear space is one of the most important components of the Jahrsdoerfer grading system (J-score), which is used to determine surgical candidacy for congenital aural atresia. The purpose of this study was to introduce a semiautomated method for measuring middle ear volume and determine whether middle ear volume, either alone or in combination with the J-score, can be used to predict early postoperative audiometric outcomes. A retrospective analysis was conducted of 18 patients who underwent an operation for unilateral congenital aural atresia at our institution. Using the Livewire Segmentation tool in the Carestream Vue PACS, we segmented middle ear volumes using a semiautomated method for all atretic and contralateral normal ears on preoperative high-resolution CT imaging. Postsurgical audiometric outcome data were then analyzed in the context of these middle ear volumes. Atretic middle ear volumes were significantly smaller than those in contralateral normal ears (P < .001). Patients with atretic middle ear volumes of >305 mm3 had significantly better postoperative pure tone average and speech reception thresholds than those with atretic ears below this threshold volume (P = .01 and P = .006, respectively). Atretic middle ear volume incorporated into the J-score offered the best association with normal postoperative hearing (speech reception threshold ≤ 30 dB; OR = 37.8, P = .01). Middle ear volume, calculated in a semiautomated fashion, is predictive of postsurgical audiometric outcomes, both independently and in combination with the conventional J-score.

Computer-Aided Nodule Assessment and Risk Yield (CANARY) may facilitate non-invasive prediction of EGFR mutation status in lung adenocarcinomas

Computer-Aided Nodule Assessment and Risk Yield (CANARY) is quantitative imaging analysis software that predicts the histopathological classification and post-treatment disease-free survival of patients with adenocarcinoma of the lung. CANARY characterizes nodules by the distribution of nine color-coded texture-based exemplars. We hypothesize that quantitative computed tomography (CT) analysis of the tumor and tumor-free surrounding lung facilitates non-invasive identification of clinically-relevant mutations in lung adenocarcinoma. Comprehensive analysis of targetable mutations (50-gene-panel) and CANARY analysis of the preoperative (≤3 months) high resolution CT (HRCT) was performed for 118 pulmonary nodules of the adenocarcinoma spectrum surgically resected between 2006–2010. Logistic regression with stepwise variable selection was used to determine predictors of mutations. We identified 140 mutations in 106 of 118 nodules. TP53 (n = 48), KRAS (n = 47) and EGFR (n = 15) were the most prevalent. The combination of Y (Yellow) and G (Green) exemplars, fibrosis within the surrounding lung and smoking status were the best discriminators for an EGFR mutation (AUC 0.77 and 0.87, respectively). None of the EGFR mutants expressing TP53 (n = 5) had a good prognosis based on CANARY features. No quantitative features were significantly associated with KRAS mutations. Our exploratory analysis indicates that quantitative CT analysis of a nodule and surrounding lung may noninvasively predict the presence of EGFR mutations in pulmonary nodules of the adenocarcinoma spectrum.

Prediction of round window visibility in cochlear implantation with temporal bone high resolution computed tomography

Objective: To discuss the prediction of round window(RW) visibility in cochlear implantation(CI) with temporal bone high resolution computed tomography(HRCT). Methods: From January 2013 to January 2017, 130 cases underwent both HRCT and CI in our hospital were analyzed. The distance from facial nerve to posterior canal wall(FWD), the angle between facial nerve and inner margin of round window(FRA), and the angle between facial nerve and tympanic anulus to inner margin of round window(FRAA) were detected at the level of round window on axial temporal bone HRCT. A line parallel to the posterior wall of ear canal was drawn from the anterior wall of facial nerve at the level of round window on axial temporal bone HRCT and its relationship with round window was detected (facial-round window line, FRL): type0-posterior to the round window, type1-between the round window, type2-anterior to the round window. Their(FWD, FRA, FRAA, FRL) relationships with intra-operative round window visibility were analyzed by SPSS 17.0 software. Results: FWD(F=18.76, P=0.00), FRA(F=34.57, P=0.00), FRAA (F=14.24, P=0.00) could affect the intra-operative RW visibility significantly. RW could be exposed completely during CI when preoperative HRCT showing type0 FRL. RW might be partly exposed and not exposed when preoperative HRCT showing type1 and type2 FRL respectively. Conclusion: FWD, FRA, FRAA and FRL of temporal bone HRCT can predict intra-operative round window visibility effectively in CI surgery.

Surgical results of modified canal wall down tympanoplasty

Conclusion: Patients with mastoiditis and chronic suppurative otitis media which has small mastoids that make them ideal candidates for modified canal wall down mastoidectomy (MCWD) which contributes to a dry and spacious ear and the maintaining and improving hearing.Objectives: To evaluate surgical outcomes for chronic otitis media underwent MCWD.Methods: A clinical retrospective study was performed on 47 ears with chronic otitis media which has relatively limited attic lesions have the small, sclerotic and hypocellular mastoids according to the preoperative high-resolution CT scan of the temporal bone that underwent MCWD and 32 ears with typical canal wall down operation form January 2010 to January 2016.Results: In the MCWD group, the mean preoperative air conduction (AC) threshold of 38.2 ± 1.1 dB was lowered to 31.0 ± 0.8 dB postoperatively (p < .01). The mean pre- and postoperative air-bone gaps (ABG) of all patients were 16.0 ± 1.0 dB and 9.6 ± 0.8 dB, respectively. In the canal wall down group, the mean preoperative AC threshold of 37.2 ± 1.0 dB was lowered to 32.8 ± 0.9 dB postoperatively (p < .01). The mean pre- and postoperative air-bone gap was reduced with 4.4 ± 0.4 dB (p < .01). There was statistical difference in hearing improvement between the modified canal wall down and the canal wall down group (p < .05).

Correlation in histological subtypes with high resolution computed tomography signatures of early stage lung adenocarcinoma.

Uncertainty remains on the association between image characteristics of the nodules in computed tomography (CT) scans and lung adenocarcinoma histopathologic subtypes. We aimed to estimate the correlation between preoperative high resolution computed tomography (HRCT) scan and postoperative histopathology of stage IA lung adenocarcinoma in East Asian Chinese population. We retrospectively reviewed the clinical records and HRCT images of 190 patients (106 female and 84 male) with resected, preoperatively untreated stage IA adenocarcinomas. The relationship between image characteristics of nodules at preoperative HRCT and their histological subtypes after resection were analyzed. The one-way ANOVA, chi-square test and logistic regression were used for analysis. In 190 patients with stage IA lung adenocarcinoma, median tumor diameter was significantly lower in lepidic predominant invasive adenocarcinoma (LPA) (15.96±6.95 mm). Univariate analysis revealed that ground-glass opacity (GGO) proportion (P<0.001), margin (P<0.001), border definition (P=0.015), pleural retraction (P<0.001) and enhancement (P<0.001) had statistically significant differences in four histological subtypes. The multivariate analysis referenced for lepidic group which indicated that GGO proportion and pleural retraction were independent associated with acinar group (RR=4.221, 95% CI: 1.770-10.066, P=0.001; RR=0.380, 95% CI: 0.158-0.916, P=0.031, respectively). Male and whose nodule margin with spiculation or lobulation were prone to papillary predominant invasive adenocarcinoma (PPA) (RR=0.288, 95% CI: 0.090-0.920, P=0.036; RR=0.250, 95% CI: 0.070-0.887, P=0.032, respectively). GGO proportion and nodule margin were independent related factors in solid predominant invasive adenocarcinoma (SPA) (RR=13.338, 95% CI: 2.974-59.811, P=0.001; RR=0.097, 95% CI: 0.016-0.606, P=0.013, respectively). Nodules with spiculation or lobulation and less GGO proportion are determinants of histological subtypes with poor prognosis in stage IA lung adenocarcinoma patients according to the 2011 histologic IASLC/ATS/ERS classification.

Vertebral artery and osseous anomalies characteristic at the craniocervical junction diagnosed by CT and 3D CT angiography in normal Czech population: analysis of 511 consecutive patients.

There are numerous indications for stabilization using instrumentation of the upper cervical spine. This area is comprised of sophisticated anatomy. There is no study describing bony and vascular anomalies of this area in the middle European population. The main aim of this study was to investigate prevalence of any vertebral artery (VA) variations and osseous anomalies in the region of the craniocervical junction in a large sample of Czech patients based on three-dimensional computed tomographic angiography (3D CTA). The VA has a variable course through C2 before it passes above its groove on the posterior arch of C1. The artery can course more medially, more posteriorly or more superiorly, thus limiting the diameter of the bony elements used as landmarks for the safe insertion of metalwork. This is known as a high-riding VA (HRVA). The VA was considered HRVA in this study if the thickness of the C2 isthmus was less than 5mm and/or the C2 internal height was less than 2mm and/or the width of the C2 pedicle was less than 4mm. The prevalence of ponticulus posticus (PP) was also identified. Following the VA variations in the V3 segment of the artery were persistent first intersegmental artery (FIA), fenestration (FEN) of the VA, and the posterior inferior cerebellar artery (PICA) branch originating from the C1/2 part of VA. Records of 511 patients from our institution were analyzed. The mean age of the patients was 63.6years. One hundred and twenty-three (24.1%) patients were identified to have HRVA, 30 (6%) present on both sides. The age of patient over 70years and female sex were found to be significant risk factors for HRVA presence. The prevalence of a nearby PICA branch was 4%, FIA was 0.4%, and FEN was 0.2%. The presence of PP was identified in 14.3% of patients. The HRVA and PP are common anomalies in the Czech population, and routine preoperative high-resolution CT evaluation is mandatory to prevent the VA injury when C1-C2 instrumentation is planned. The female sex and age over 70years were found to be the most important factors for HRVA presence. The FIA and the FEN VA were rare in our study contrary to reports published from Asia, showing as many as a 10% the VA presence over the starting point for C1 lateral screw. On the basis of the infrequent occurrence of these anomalies, we do not recommend routine CT angiography when upper cervical spine instrumentation in the normal population is planned.

Quantitative analysis of craniofacial dysmorphology in infants with anterior synostotic plagiocephaly

The study aimed to identify premature synostosis of "major" and "minor" sutures of the coronal sutural arch and splanchnocranium sutures to evaluate the relationship between craniofacial dysmorphology and the sutural pattern in children with anterior plagiocephaly. A quantitative analysis of the skull base and facial changes was performed on preoperative high-resolution CT images in 18 children with anterior synostotic plagiocephaly and compared with imaging findings in 18 age-matched healthy subjects. All patients had patent splanchnocranium sutures. Fifteen out of 18 children showed early and isolated synostosis of the unicoronal suture (the major suture of the coronal ring) and were classified in groups II and III according to the classification scheme of anterior synostotic plagiocephaly based on the severity of craniofacial dysmorphology. Premature fusion of the unilateral coronal suture in groups II and III caused a marked asymmetry and reduced growth of the anterior and middle fossae on the synostotic side and a secondary varying severity in terms of asymmetric growth of the facial complex. Although both groups showed anterior displacement of the mandibular articulation on the synostotic side, group II showed only maxillary asymmetry, while group III showed maxillary and mandibular asymmetry. In anterior synostotic plagiocephaly, the severity of skull base changes and asymmetric growth of the facial complex is not caused by skull base sutural synostotic involvement but is probably related to the different timing of unilateral coronal suture closure.

Comparison of Preoperative Temporal Bone HRCT and Intraoperative Findings in Patients with Chronic Otitis Media

Objective: The aim of the present study was to investigate the diagnostic confidence level of preoperative 160-slice computed tomography (CT) findings compared with that of perioperative findings about anatomic variations in the structure of the facial canal, lateral semicircular canal, and dural plate. Materials and Methods: Fifty-five patients who presented with middle ear pathology to Department of Otolaryngology, Afyon Kocatepe University Faculty of Medicine were included in the study, and the mean age was 42 (±15.55) years. Preop- erative CT images of the temporal bone were obtained by an 80-detector row CT scanner. Results: The sensitivity, specificity, and positive and negative predictive values of preoperative high-resolution CT (HRCT) were 52%, 88%, 73%, and 75%, respectively, for determining the presence of facial canal dehiscence; 50%, 89%, 71%, and 76%, respectively, for determining the presence of tympanic segment dehiscence; 71%, 96%, 71%, and 96%, respectively, for determining the presence of lateral semicircular canal dehiscence; and 100%, 96%, 50%, and 100%, respectively, for detecting the presence of dural plate defects. Conclusion: The compatibility of HRCT findings with surgical findings in determining the presence of dehiscence of the facial canal and its tympanic segment was moderate, while it was good in determining the presence of dehiscence of the lateral semicircular canal and the defect of the dural plate.

Role of "major" and "minor" lambdoid arch sutures in posterior cranial fossa changes: mechanism of cerebellar tonsillar herniation in infants with multisutural craniosynostosis.

This study aimed to explain the functional role of lambdoid arch sutures in the development of cerebellar tonsillar herniation. Posterior cranial fossa (PCF) changes were investigated in infants with premature synostosis of the major and minor sutures of the lambdoid arch without premature synostosis of the PCF synchondroses. Morphometric and volumetric PCF measurements were performed on preoperative high-resolution CT studies in 12 infants with multisutural craniosynostosis involving the lambdoid arch and compared with those of 12 age-matched healthy subjects. All 12 patients had hypoplasia of PCF bone structures and normal volumes of the PCF and neural structures. PCF hypoplasia was related to exocciput length in infants with isolated involvement of major sutures, while it was related to posterior skull base hemifossae in infants with isolated involvement of minor lambdoid arch sutures. Foramen magnum AP diameter was reduced in babies with major suture involvement and tonsillar herniation, while foramen magnum AP and LL diameters were reduced in babies with minor suture involvement without tonsillar herniation. Right and left jugular foramen (JF) areas differed in all infants; however, the area of the smaller JF was significantly reduced only in infants with involvement of minor lambdoid arch sutures. Hypoplasia of PCF bone structures due to sutural synostosis of the lambdoid arch is a required predisposing but not sufficient factor for the development of cerebellar tonsillar herniation through the foramen magnum. Normal PCF volume and foramen magnum anatomy may partly explain the development of cerebellar tonsil herniation in infants with lambdoid arch synostosis.

Qualitative Analysis of Preoperative High-Resolution Computed Tomography: Risk Factors for Pulmonary Complications After Major Lung Resection

Postoperative pulmonary complications after major lung resection are strongly associated with mortality. Qualitative findings of emphysema, bronchiectasis, and bronchial wall thickening on high-resolution computed tomography (HRCT) are indicators of chronic obstructive pulmonary disease and may serve as risk factors for pulmonary complications. The subjects were 347 consecutive patients who underwent single lobectomy for pulmonary malignancy from May 2010 to December 2014. Correlations of pulmonary complications with preoperative clinical factors and HRCT findings were retrospectively examined using multivariate logistic regression analysis to compare the predictive ability for pulmonary complications using clinical variables that were reported to be risk factors. Patients who had pulmonary complications were more frequently male (p < 0.001), with a greater smoking history (p < 0.001), lower rate of steroid use (p < 0.001), more frequent emphysema on HRCT (p < 0.001), more frequent bronchiectasis on HRCT (p = 0.002), more frequent bronchial wall thickening on HRCT (p < 0.001), and higher rate of extended resection (p = 0.006). In multivariate analysis, HRCT findings (odds ratio [OR] 12.01, 95% confidence interval [CI]: 5.582 to 25.83, p < 0.001) and extended resection (OR 7.726, 95% CI: 1.678 to 35.57, p = 0.009) were independent risk factors for pulmonary complications. After matching of risk factors between patients with and without pulmonary complication, emphysema (OR 3.394, 95% CI: 1.781 to 6.469, p < 0.001) and bronchial wall thickening (OR 6.250, 95% CI: 2.414 to 16.18, p < 0.001) were independently associated with pulmonary complications in the model with better performance. Qualitative findings on HRCT are independent risk factors for pulmonary complications after lobectomy. Preoperative HRCT may be useful to predict pulmonary complications.

Predicting depth of electrode insertion by cochlear measurements on computed tomography scans.

To evaluate the effectiveness of cochlear measures obtained by high-resolution computed tomography (HRCT) scan in predicting depth of cochlear implant insertion. Retrospective case review. Patients who underwent cochlear implantation in an academic referral center between 2010 and 2013 were considered. Inclusion criteria included available preoperative HRCT scan and complete operative data. Subjects with labyrinthitis ossificans, cochlear hypoplasia, or major inner ear malformations were excluded. Subsequently, measures of cochlear height in the coronal plane and basal turn width in the axial plane were obtained using electronic calipers of the stored digital HRCT images by a blinded investigator. The insertion was considered deep when the electrode was placed at least 23 mm into the cochlea. Subjects were divided into those who had a deep insertion and those who did not. Regression analyses were done to associate cochlear measures with deep insertion. A deep insertion was possible in 25 patients out of 35. There was no statistically significant association between deep insertion and age at implantation, gender, and type of cochleostomy. The mean cochlear height was 6.22 mm (standard deviation [SD] = 0.32 mm) and 5.80 mm (SD = 0.3mm) in subjects with and without deep insertion, respectively (Student t test, P = .0015). Only cochlear height showed an association with deep insertion (logistic regression, P = .0007). For a cochlear height of 6.27 mm, the probability of deep insertion was 0.90. Linear measurements of standard CT scans of the cochlea can predict the depth of insertion and may help the selection of the appropriate electrode array preoperatively. 4. Laryngoscope, 126:1656-1661, 2016.

THE ROLE OF HRCT IN EVALUATION OF AQUAIRED MIDDLE EAR CHOLESTEATOMA OTITIS PRIOR SURGERY

Otoscopic examination is the best method for diagnosis of cholesteatoma which treated by explorative surgery. The need for pre-operative imaging studies is controversial. This study assesses the accuracy and usefulness of a pre-operative high-resolution CT scan in depicting the status of the middle ear structures in the presence of cholesteatoma. Patients and Methods: the surgical findings of 88 patients with acquired cholesteatoma were compared with the pre-operative CT findings in this prospective study. The following were analyzed: diagnostic features of cholesteatoma on CT, status of the middle ear structures (ossicles, facial nerve canal, bony labyrinth, tegmen tympani and scutum) and extension of the disease to the sinus tymapni and facial recess. Results: eighty-three (94.3%) cases had the two radiological features characteristic for cholesteatoma (a) a location typical for cholesteatoma in the epitympanum and mastoid antrum (b) bony erosion. The radio-surgical agreement was excellent for the malleus (Kappa statistics, K= 0.96), stapes (0.91), bony labyrinth (0.94), tegmen tympani (0.82) and scutum (1), good for the incus (0.75), but poor for the facial nerve canal (0.39). The scan accurately predicted the extension of the disease to the sinus tympani and facial recess. Conclusion: High-resolution CT scan is an important investigative tool prior to cholesteatoma surgery.There is good to excellent radio-surgical correlation in cholesteatoma for most middle ear structures except for the integrity of the facial canal. The scan alerts the surgeon to asymptomatic complication of the disease.

A novel tool for three-dimensional roadmapping reduces radiation exposure and contrast agent dose in complex endovascular interventions

The volume and complexity of endovascular procedures are increasing. Multidetector computed tomography (CT) made precise three-dimensional (3D) planning of these procedures possible, but intraoperative imaging, even with the use of modern flat-panel detectors, is limited to two dimensions. Flat detectors, however, allow C-arm cone-beam CT. This technology can be used to generate a 3D data set that can be fused with a preoperative high-resolution CT scan, thus generating a live 3D roadmap. We hypothesized that use of a novel image fusion software, VesselNavigator (Philips Healthcare, Best, The Netherlands), facilitates precise and expeditious procedures and therefore reduces radiation exposure and contrast agent dose. A retrospective review of patients undergoing standard aortobi-iliac endovascular aneurysm repair at our institution between January 2011 and April 2014 was performed. Conventional imaging was compared with VesselNavigator-assisted imaging, and a matched analysis based on body mass index (BMI) was performed because of the dependence of radiation dose on body habitus. Outcome parameters were procedure time, fluoroscopy time, radiation, and contrast agent dose. A total of 75 patients were identified. After matching based on BMI, control and VesselNavigator groups each had 16 patients with BMI of 27.0 ± 3.6 kg/m(2) and 27.0 ± 3.6 kg/m(2), respectively (mean ± standard deviation). R(2) was 6.37 × 10(-7). Radiation dose measured as air kerma was lower with VesselNavigator (1067 ± 470.4 mGy vs 1768 ± 696.2 mGy; P = .004). Fluoroscopy time was shorter (18.4 ± 6.8 minutes vs 26.8 ± 10.0 minutes; P = .01) and contrast agent dose was lower (37.4 ± 21.3 mL vs 77.3 ± 23.0 mL; P < .001) with VesselNavigator compared with control. Procedure time was also shorter with VesselNavigator (80.4 ± 21.2 minutes vs 110.0 ± 29.1 minutes; P = .005). Image fusion using VesselNavigator enhances the functionality of conventional fluoroscopy in standard endovascular aneurysm repair. It reduces radiation exposure to patients and providers. It also limits the amount of contrast agent and shortens the overall procedure length. The benefit of this technology is demonstrated on this typically straightforward procedure but may be even more useful for complex procedures.