Consecutive Computed Tomography Scans Research Articles

Morphological Analysis of Metacarpal Shafts With Respect to Retrograde Intramedullary Headless Screw Fixation.

Background: The use of retrograde intramedullary headless compression screw fixation for metacarpal neck and shaft fractures has been described in the literature. The purpose of this study was to perform a computed tomography (CT)-based morphological analysis of metacarpal size to help surgeons anticipate expected hardware needs. Methods: In all, 108 consecutive hand CT scans were evaluated for the medullary diameter in the volar-dorsal and radial-ulnar planes at the narrowest point of the canal, as well as for the distance from the articular surface to this point. Results were then analyzed by finger and by sex. Results: The ring finger had the smallest average medullary canal diameter for both men and women (2.7 and 2.6 mm, respectively); the small finger had the largest average diameter (3.9 mm) for men and the middle finger (3.6 mm) for women. Radial-ulnar was the rate-limiting dimension in the index, middle, and ring fingers, whereas volar-dorsal was the smallest dimension in the small finger, regardless of sex. Medullary diameter tended to be larger in patients aged more than 50 years. More than 50% of fingers have diameters >3.0 mm, and at least 40% of index, middle, and small fingers have diameters >3.5 mm, which are common diameters of commercially available headless compression screws. Conclusions: When preparing to perform open reduction internal fixation of a metacarpal using retrograde intramedullary headless compression screws, the surgeon needs to be prepared with screws of larger diameters to optimize fixation. Screws of larger diameters are needed to achieve endosteal purchase, regardless of sex.

Developmental anomalies of the lateral portion of the cervical neural arch: Multimodal imaging and clinical implications.

This study aimed to describe the imaging spectrum of developmental anomalies of the lateral portion of the cervical neural arch. This was a five-year retrospective review of consecutive computed tomography (CT) scans of the cervical spine for structural anomalies of the cervical vertebral pedicle and facets. CT, radiographs and, when available, magnetic resonance imaging studies were independently reviewed. Anomalies were grouped into the following three categories: the absence of a pedicle, clefts in the vertebral arch or isolated dysmorphism of the facet. Clinical data on demographics and neurological outcomes were documented. Among 9134 consecutive patients undergoing a CT scan of the cervical spine, 18 (0.2%) patients were found to have developmental anomalies of the pedicle and facets. Findings included 7/18 (39%) with congenital absence of a pedicle, 8/18 (44%) with clefts in the vertebral arch and 3/18 (17%) with isolated dysmorphism of the articular facets. No acute neurological deficits or spinal cord injuries were reported. Associated chronic symptoms included neck pain 10/18 (56%), radiculopathy 7/18 (39%) and myelopathy 1/18 (6%). Developmental anomalies of the pedicle and facet may mimic traumatic spinal pathologies. Recognising a diverse spectrum of imaging findings is vital to prevent misdiagnosis and unnecessary intervention.

Risk of bony violation with standard triple screw configurations for fixation of femoral neck fractures: A preliminary computed tomography based analysis

PurposeThe reduction and fixation of femoral neck fractures is mainly an indirect one with intraoperative fluoroscopy being trusted for the safe containment of screws within the bony limits of the femoral neck. Radiologically undetected bony perforations may have an impact on the fracture stability and radiological outcomes that have not been studied previously. The purpose of this computed tomography (CT) based study is to analyze the safety of containment of triple screw configurations using standard 6.5 mm diameter screws for fixation of femoral neck fractures in the Indian population using a software-based analysis. MethodsData from consecutive CT scans with intact proximal femur performed over a six month period were retrospectively analyzed using iPlan® BrainLab AG, Feldkirchen, Germany. The safe containment of virtual screw trajectories placed in inverted triangular and non-inverted triangular configurations for a 6.5 mm diameter screw was analyzed in intact femoral necks. ResultsA total of 72 cases were considered for the final assessment. For 6.5 mm screws, the proportion for safe containment (without bony violation) of triple screw inverted triangular configuration was 75% with additional safety corridor to 1 mm around the screw trajectories and 31.94% for non-inverted triangular configuration. All male cases and 28% of female cases allowed safe placement of three 6.5 mm screw trajectories in an inverted triangular pattern with a safety margin of 1 mm around the screw. Replacement of one of the two superior 6.5 mm diameter screw trajectories with a 4.5 mm diameter trajectory resulted in 100% safe containment in female cases. ConclusionInverted triangular configuration is a relatively safer configuration compared to the non-inverted triangular configuration. Standard triple 6.5 mm screws for fixation of femoral neck fractures carry a risk of bony violation, especially in females. A preoperative radiographic assessment to screen the cases with narrow vertical and anteroposterior extents of the femoral neck can help in reducing the risk of fluoroscopically undetected violation of the bony margins. Replacement of one of the two superior screws with a 4.5 mm diameter screw can be helpful in such cases.

Dosimetric assessment of patient-specific breath-hold reproducibility on liver motion for SBRT planning.

PurposeTo investigate the impact of breath‐hold reproducibility on liver motion using a respiratory motion management device.MethodsForty‐four patients with hepatic tumors, treated with SBRT with breath‐hold, were randomly selected for this study. All patients underwent three consecutive computed tomography (CT) scans using active breath‐hold coordinator (ABC) with three repeated single breath‐hold during simulation. The three CT scans were labeled as ABC1‐CT, ABC2‐CT, and ABC3‐CT. Displacements of centroids of the entire livers among the three ABC‐CTs were measured as a surrogate for intrafractional motion. For each patient, two different treatment plans were prepared: (a) a clinical plan using a 5‐mm expansion of an ITV that encompassed all three GTVs from each of the three ABC‐CTs, and (b) a research plan using a 5‐mm expansion of the GTV from only ABC1‐CT to create PTV. The clinical plan acceptance criteria were that 95% of the PTV and 99% of the GTV received 100% of the prescription dose. Dosimetric endpoints were analyzed and compared for the two plans.ResultsAll shifts in the medial‐lateral direction (range: −3.9 to 2.0 mm) were within 5 mm while 7% of shifts in the anterior–posterior direction (range: −10.5 to 16.7 mm) and 11% of shifts in the superior–inferior direction (range: −17.0 to 8.7 mm) exceeded 5 mm. Six patients (14%) had an intrafraction motion greater than 5 mm in any direction. For these six patients, if a plan was created based on a PTV from a single CT (ex. ABC1‐CT), 5 of 12 GTVs captured from other ABC‐CTs would fail to meet the clinical acceptance criteria due to poor breath‐hold reproducibility.ConclusionsNon‐negligible intrafractional motion occurs in patients with poor breath‐hold reproducibility. To identify this subgroup of patients, acquiring three CTs with active breath‐hold during simulation is a feasible practical method.

Computed tomography assessment of anterior ethmoidal canal dehiscence: An interobserver agreement study and review of the literature.

The anterior ethmoidal artery can be injured in functional endoscopic sinus surgery. The ability of computed tomography (CT) to identify dehiscence of the anterior ethmoidal canal (AEC) has not been widely evaluated. The aim of this study was to evaluate the interobserver agreement in the CT assessment of AEC dehiscence. We conducted a retrospective review of consecutive CT scans of the paranasal sinuses (PNS) between January 1, 2012, and December 31, 2012. Two neuroradiologists separately assessed the presence of AEC dehiscence, the presence of PNS opacification, and the best CT plane to evaluate the AEC. Statistical analysis included descriptive analysis and interobserver agreement (kappa coefficient). The AEC was below the skull base in 199 (22.3%) cases. Dehiscence of the AEC was found in 13.2% for reader 1 and in 7.3% for reader 2. The interobserver agreement for identification of AEC dehiscence was only fair (κ = 0.246). The interobserver agreement for the AEC dehiscence in cases with opacification of ethmoidal air cells was substantial (κ = 0.754). The suboptimal interobserver agreement could potentially limit the usefulness of CT scans for routine assessment of AEC dehiscence. In patients with PNS opacification, CT scans could still add valuable information regarding AEC dehiscence.

Factors associated with subcentimeter pulmonary nodule outcomes followed with computed tomography imaging in oncology patients

IntroductionTechnological advancements in computed tomography (CT) have enabled the frequent detection of small pulmonary nodules (PNs), especially in patients with an oncologic history. It is important the malignant versus benign etiology of PNs be determined. The aim of the present study was to evaluate the behavior and clinical/radiological characteristics of subcentimeter PNs detected by CT in oncologic patients. MethodsAn observational, longitudinal, retrospective and single-center study was conducted with a sample of 100 patients with a diagnosis of a primary malignant solid tumor outside of the lungs who developed indeterminate subcentimeter PNs (n = 251) detected on consecutive thoracic CT scans from 2015 to 2017. Follow-up CTs for each patients were examined in each of three periods (0–3 months, 3–6 months, and 6 months to 1 year). ResultsIn our study sample, 28 patients (28 %) showed one or more signs suspicious of pulmonary metastasis, including ≥50 % PN growth, nodule growth followed by size reduction in patients undergoing chemotherapy, and the appearance of multiple nodules. The majority (56 %) of the PNs were detected during the 3–6-month follow-up CT scan. PNs with irregular, lobuled, or spiculated margins exhibited faster growth than PNs with regular, smooth margins. Malignancy of PNs was found to be significantly associated with being male, a primary colorectal cancer diagnosis, and advanced stage disease. ConclusionOur findings reinforce the necessity of an individualized CT follow-up strategy for patients with an oncologic history, as well as the importance of early nodule screening, with the inter-scan interval being dependent on the primary neoplasm.

Morphometric Measurements of Cranio-Vertebral Junction among Nepalese Population

The craniovertebral junction area refers to the osseous structures consisting of the occipital bone that surrounds the foramen magnum, the atlas, and the axis vertebrae. There is sparse literature about the morph metric measurement of craniovertebral junction region. We aim to derive a range of various measurements incraniovertebral junction area. This is a hospital based single center retrospective study conducted in our center among 100 consecutive computed tomography scans of craniovertebral junction obtained in adult patients who were admitted to our tertiary hospital for treatment of non-craniovertebraljunction conditions between 2017 and 2018.Various craniovertebral junction morphology parameters were measured and confidence interval at 95% were obtained the range at 2standard deviation. Among 100 patients studied, 51% of them were males while 49% were females. Mean age was 35.1±10.4 years with range from 15 to50 years. Computed tomography measurement of craniovertebral junction revealed meanders height of 30.8±2.5 mms, dento-clivaldistance was 5.9±1.6 mms and mean McRae’s distance of 34.2±2.49 mms. Similarly, anterioratlantodental interval was calculated to be1.83±0.47 mms and posterior atlantodentalinterval was 17.72±0.21 mms while Modified RW distance was 24.43±2.09 mms and Redlund Johnell distance was calculated to be 31.5±4.29mms. Normal morphometric measurements ofcraniovertebral junction can be useful for evaluating abnormalities of the craniovertebraljunction which can potentially improve the diagnostic criteria of most abnormalities.

Heterogeneous and dynamic lumen remodeling of the entire infrainguinal vein bypass grafts in patients

ObjectiveTo examine the regional variation and temporal change in lumen size along the entire autogenous vein bypass graft used for treating arterial occlusive disease in lower extremity and to explore the factors associated with graft expansive or constrictive remodeling. MethodsPatients were prospectively scanned using contrast-enhanced computed tomography at 1 week and 1, 6, and 12 months postoperatively to obtain lumen cross-sectional areas at 1-mm intervals along the entire grafts. Graft lumen remodeling characteristics and the associated demographic and clinical factors were examined. ResultsFifty-six patients with at least two consecutive computed tomography scans were analyzed. Patients with a composite or longer graft, or with diabetes, had a larger lumen cross-sectional area variation along the graft. The mean lumen cross-sectional areas of all the grafts demonstrated no significant changes through 12 months. However, individually, graft remodeling was time dependent and there was a more dramatic change in lumen cross-sectional area within the first postoperative month. At 12 months, a near equal distribution between expansive and constrictive grafts existed. A negative relation between the initial lumen diameters and the subsequent lumen diameter changes was observed. Eleven grafts failed within 12 months; failed and patent grafts had similar mean lumen cross-sectional areas at all four time points, but failed grafts had a larger maximal local cross-sectional area reduction from 1 week to 1 month (58.0 ± 6.7% vs 38.1 ± 3.1%, mean ± standard error of the mean, failed vs patent, P = .004). Black patients had a smaller mean lumen cross-sectional area than white patients at all four time points and also had a higher early percent mean area reduction (−20.5 ± 6.3% vs −1.0 ± 3.7%, black vs white, P = .018). Cilostazol use was associated with early expansive graft remodeling. ConclusionsVein grafts remodel heterogeneously and dynamically. Remodeling is associated with initial graft lumen size, race, and cilostazol use. It is found that remodeling that produces some critical minimum area or maximal percent reduction during the first postoperative month may predispose to vein graft failure. These findings offer insight into further investigation to examine the underlying mechanisms and opportunities to improve graft remodeling and durability.

Effect of Ionizing Radiation from Computed Tomography on Differentiation of Human Embryonic Stem Cells into Neural Precursors.

We studied the effect of radiation from computed tomography (CT) scans on differentiation of human embryonic stem cells (hESCs) into neuronal lineage. hESCs were divided into three radiation exposure groups: 0-dose, low-dose, or high-dose exposure. Low dose was accomplished with a single 15 mGy CT dose index (CTDI) CT scan that approximated the dose for abdominal/pelvic CT examinations in adults while the high dose was achieved with several consecutive CT scans yielding a cumulative dose of 500 mGy CTDI. The neural induction was characterized by immunocytochemistry. Quantitative polymerase chain reaction (qPCR) and Western blots were used to measure expression of the neuronal markers PAX6 and NES and pluripotency marker OCT4. We did not find any visible morphological differences between neural precursors from irradiated and non-irradiated cells. However, quantitative analyses of neuronal markers showed that PAX6 expression was reduced following exposure to the high dose compared to 0-dose controls, while no such decrease in PAX6 expression was observed following exposure to the low dose. Similarly, a statistically significant reduction in expression of NES was observed following high-dose exposure, while after low-dose exposure, a modest but statistically significant reduction in NES expression was only observed on Day 8 of differentiation. Further studies are warranted to elucidate how lower or delayed expression of PAX6 and NES can impact human fetal brain development.

Skeletal muscle mass loss and dose-limiting toxicities in metastatic colorectal cancer patients.

BackgroundIncreasing evidence suggests that severe skeletal muscle index (SMI) loss (sarcopenia) is associated with poor overall survival in metastatic colorectal cancer patients, but its mechanisms are unknown. We recently found, using data of the randomized phase 3 CAIRO3 study, that SMI loss was related with shorter time to disease progression and overall survival during first‐line maintenance treatment with capecitabine + bevacizumab (CAP‐B) or observation and during more intensive capecitabine + oxaliplatin + bevacizumab (CAPOX‐B) reintroduction treatment. As a potential risk factor for reduced survival, we explored whether sarcopenia and SMI loss were associated with dose‐limiting toxicities (DLTs) during CAP‐B and CAPOX‐B.MethodsSarcopenia status and SMI loss were assessed by using consecutive computed tomography scans. DLTs were defined as any dose delay/reduction/discontinuation of systemic treatment because of reported CTCAE (version 3.0) toxicities at the start or during treatment. Poisson regression models were used to study whether sarcopenia and body mass index (BMI) at the start of treatment and SMI and BMI loss during treatment were associated with DLTs.ResultsOne hundred eighty‐two patients (mean age 63.0 ± 8.8 years, 37% female) received CAP‐B, and 232 patients (mean age 63.0 ± 9.0 years, 34% female) received CAPOX‐B. At the start of CAP‐B and CAPOX‐B, 54% and 46% of patients were sarcopenic, respectively. Mean BMI was lower in sarcopenic patients, although patients were on average still overweight (sarcopenic vs. non‐sarcopenic at the start of CAP‐B 25.0 ± 3.9 vs. 26.7 ± 4.1 and CAPOX‐B 25.8 ± 3.8 vs. 27.1 ± 3.8 kg/m2). Sarcopenia at the start of CAP‐B was not associated with DLTs [relative risk 0.87 (95% confidence interval 0.64–1.19)], whereas patients with >2% SMI loss had a significantly higher risk of DLTs [1.29 (1.01–1.66)]. At the start of subsequent CAPOX‐B, 25% of patients received a dose reduction, and the risk of dose reduction was significantly higher for patients with preceding SMI loss [1.78 (1.06–3.01)] or sarcopenia [1.75 (1.08–2.86)]. After the received dose reductions, sarcopenia or SMI loss was not significantly associated with a higher risk of DLTs during CAPOX‐B [sarcopenia vs. non‐sarcopenic: 0.86 (0.69–1.08) and SMI loss vs. stable/gain: 0.83 (0.65–1.07)]. In contrast, BMI (loss) at the start or during either treatment was not associated with an increased risk of DLTs.ConclusionsIn this large longitudinal study in metastatic colorectal cancer patients during palliative systemic treatment, sarcopenia and/or muscle loss was associated with an increased risk of DLTs. BMI was not associated with DLTs and could not detect sarcopenia or SMI loss. Prospective (randomized) studies should reveal whether normalizing chemotherapeutic doses to muscle mass or muscle mass preservation (by exercise and nutritional interventions) increases chemotherapeutic tolerance and improves survival.

Prospective Evaluation of Neoadjuvant Imatinib Use in Locally Advanced Gastrointestinal Stromal Tumors: Emphasis on the Optimal Duration of Neoadjuvant Imatinib Use, Safety, and Oncological Outcome.

Background: Neoadjuvant imatinib therapy has been proposed for routine practice with favorable long-term results for patients with locally advanced gastrointestinal stromal tumors (GISTs). However, clarification of the optimal duration, safety, and oncological outcomes of neoadjuvant imatinib use before surgical intervention remains necessary. Methods: We prospectively analyzed the treatment outcomes of 51 patients with locally advanced, nonmetastatic GISTs treated with neoadjuvant imatinib followed by surgery. The optimal duration was defined as the timepoint when there was a <10% change in the treatment response or a size decrease of less than 5 mm between two consecutive computed tomography scans. Results: Primary tumors were located in the stomach (23/51; 45%), followed by the rectum (17/51; 33%), ileum/jejunum (9/51; 18%), and esophagus (2/51; 4%). The median maximal shrinkage time was 6.1 months, beyond which further treatment may not be beneficial. However, the maximal shrinkage time was 4.3 months for the stomach, 8.6 months for the small bowel and 6.9 months for the rectum. The R0 tumor resection rate in 27 patients after neoadjuvant imatinib and surgery was 81.5%, and 70.4% of resection procedures succeeded in organ preservation. However, 10 of 51 patients (19.6%) had complications following neoadjuvant imatinib use (six from imatinib and four from surgery). Conclusion: Our analysis supports treating GIST patients with neoadjuvant imatinib, which demonstrated favorable long-term results of combined therapy. However, careful monitoring of complications is necessary. The optimal duration of neoadjuvant imatinib use before surgical intervention is, on average, 6.1 months.

Hyperprogressive disease (HPD) in genitourinary (GU) cancer patients treated with PD-1/PD-L1 inhibitors.

369 Background: Post immunotherapy response and disease progression pattern are still under investigation. In terms of progression, rapid progression pattern called HPD has been observed during the early cycles of PD-1/PD-L1 inhibitors therapy in patients with various cancers. Data of HPD in patients with GU cancer are limited. Methods: This study included 203 patients with GU cancer treated with PD-1/PD-L1 inhibitors between February 2015 and June 2018. HPD was defined as greater than 50% increase in tumor burden compared with before-treatment computed tomography (CT) scan and greater than 2-fold increase in tumor growth rate (TGR) compared with previous TGR. Development of extensive new lesions were also regarded as HPD. Response was evaluated by RECIST v1.1 on at least two consecutive CT scan before the initiation of PD-1/PD-L1 inhibitors and one CT scan within 2 months after initiation of PD-1/PD-L1 inhibitors. Results: 102 patients with renal cell carcinoma (RCC) and 101 patients with urothelial cell carcinoma (UCC) were included. Median age was 64 years (range 56-71) and 141 patients (70%) were male. The most common metastatic site was lymph node (66%), followed by lung (51%) and bone (34%). HPD was observed in 13 out of 230 patients (5.7%; 95% CI, 5.0-6.3). Median OS for patients with progressive disease and HPD were 7.3 months and 3.5 months, respectively ( p=0.09). HPD was more frequently found in patients with UCC than RCC (11% vs. 0.9%, p=0.01). In multivariate analysis, patients of UCC ( p &lt;0.001), presence of liver metastasis ( p=0.002), elevated LDH level (&gt; upper normal limit, p=0.01), and hypoalbumimemia (&lt; 3.5 gm/dL, p&lt;0.001) were independent predictive factors for HPD. Conclusions: The incidence of HPD in GU cancer patients seems to be low compared to previous studies (9-10%). The majority of HPD developed in UCC and the incidence in RCC is negligible. Cares should be taken when treating patients with PD-1/PD-L1 inhibitors, especially when patients have UCC and liver metastases, elevated LDH and hypoalbuminemia.

Prevalence and Types of Aortic Arch Variants and Anomalies in Congenital Heart Diseases

Aortic arch (AA) variants and anomalies are important to recognize in patients with congenital heart disease (CHD) before surgery or intervention. The aim was to study the prevalence of AA anomalies and variants in patients with CHD compared to a control group. The secondary outcome was to report the associations between common variations of AA and specific types of CHD. After institutional review board approval, computed tomography studies of 352 CHD patients and control group of 400 consecutive computed tomography scans of the thorax were evaluated. The AA was assigned to one of seven common types, and their distribution was compared between CHD and control. The distribution of the AA anomalies and variants was evaluated as regard specific types of CHD and the visceroatrial situs. Normal three-vessel branching pattern was the commonest in both groups, but was present in only 50.5% in the CHD compared to 68.5% in the control group, p < 0.00001. Right AA and aberrant right subclavian artery were significantly more common in CHD than control group (18.1% versus 0.25%, p < 0.00001) and (4.5% versus 0.25%, p = 0.0001), respectively. Direct aortic origin of left vertebral artery was insignificantly more common in CHD group (4.2% versus 2.7%, p = 0.258). Brachiobicephalic trunk was significantly more common in control than CHD group (27.7% versus 19.3%, p = 0.007). Normal three-vessel AA was significantly less common in CHD. AA anomalies (right arch and aberrant right subclavian) were more common in CHD than control, while AA variants (brachiobicephalic trunk and direct aortic origin of left vertebral artery) were not.

188 Impact of Adult Level 1 Trauma Designation on the Timeliness of Pediatric Emergency Department Computed Tomography Scans

Timeliness in the provision of medical care is an essential aspect of patient safety and health care quality. Given the unpredictable nature of the emergency department (ED) with regards to variation in disease acuity and patient volume, it is essential to gather crucial information in a prompt fashion to aid medical decisionmaking and patient disposition. The adult emergency department of our institution was verified as a Level 1 Trauma Center by the American College of Surgeons in December 2015, 24 years after our pediatric emergency department was recognized as a Level 1 Trauma Center. One of the metrics used as an operational benchmark in the ED is imaging interval (time from order of an imaging test to the availability of results). There is a single computed tomography (CT) scanner located in the emergency department, which is utilized by both the adult and pediatric sections. With an anticipated increase in the adult ED patient volume following its new status, we sought to assess the impact of adult Level 1 Trauma designation on the timeliness of pediatric non-trauma CT scans in an emergency department. Retrospective chart review of patients in the pediatric emergency department who had CT scans was performed. We compared CT scan orders of patients over the same 6-month period prior to and after the adult ED Level 1 Trauma verification, and assessed the time from order to completion of CT scans. The months with historically highest trauma volumes were chosen. All pediatric trauma activations were excluded, as well as duplicate orders and scans performed during EMR downtime. Unpaired student t-tests and Chi-squared tests were used for statistical analyses. There were 218 consecutive CT scans analyzed in 2015, and 193 consecutive CT scans in the same time frame in 2016. About half of the CT scans in both years were head imaging studies, and more males were scanned compared to females. The average time for CT completion prior to adult ED Level 1 verification was 39.5 minutes, compared to 55.5 minutes in the same time frame the next year (p<0.0001). Also, the proportion of children receiving CT scans within 60 minutes from order decreased from 81% in 2015 to 65% in 2016. (p=0.0002; 95% CI 7.4 - 24.4). The new designation of adult Level 1 trauma status in our ED was associated with a significant delay (by more than 40%) in performance of non-trauma pediatric CT scans, and decrease in the likelihood of children receiving CT scans within 60 minutes. These findings may have significant clinical and economic ramifications for pediatric patients and hospitals, and represent the potential "collateral damage" of an institution receiving an upgrade of their adult trauma center to Level 1 status.

Cartilaginous Eustachian tube length and carotid canal dehiscence in children: a radiological study.

The use of Balloon Eustachian tuboplasty (BET) for Eustachian tube dysfunction is increasing in adults but to a lesser extent in children. Despite growing experience, concerns remain that BET could theoretically cause carotid artery rupture, which may be more likely if there is carotid canal dehiscence adjacent to the bony Eustachian tube. This radiological study aims to assess the prevalence of carotid canal dehiscence and length of cartilaginous Eustachian tube in children. 75 consecutive computed tomography scans of the petrous temporal bones performed in children were identified (150 carotid canals/Eustachian tubes). Two independent raters measured the length of the cartilaginous Eustachian tube and thickness of carotid canal wall. 8% of carotid canals had radiological dehiscence. Prevalence of carotid canal dehiscence on either side per child was 12%. Mean cartilaginous Eustachian tube length was 24.5mm (SD 3.1mm) and the minimum measured was 14.1mm. The minimum length measured in a child over 3years old (n = 65) was 18.1mm. The mean thickness of bone of the carotid canal was 0.7mm (SD 0.27mm). There was a positive relationship between age and Eustachian tube length (Pearson's correlation coefficient = 0.622, p < 0.001). Carotid canal dehiscence in children has a low prevalence. Variation in the length of the cartilaginous Eustachian tube is low but is correlated with age. More research is required to define the indications, safety, efficacy and technical aspects of BET in children.

Comparison of Three Different Options for C7 Posterior Vertebral Anchor in the Indian Population-Lateral Mass, Pedicle, and Lamina: A Computed Tomography-Based Morphometric Analysis.

Study Design Radiological cohort study.PurposeThe options of posteriorly stabilizing C7 vertebra include using lateral mass, pedicle or lamina, as bony anchors. The current study is a computed tomography (CT)-based morphometric analysis of C7 vertebra of 100 Indian patients and discusses the feasibility of these different techniques.Overview of LiteratureC7 is a peculiar vertebra with unique anatomy, which poses challenges for each of these fixation modalities. There are no reports available in the literature, which discuss and compare the feasibility of diverse posterior C7 fixation techniques in Indian population.MethodsWe included 100 consecutive cervical spine CT scans of Indian patients performed between July 2016 and September 2016. We excluded CT scans with any significant congenital anomaly or other pathological lesions of C7 and patients with non-Indian ethnicity. Regarding screw placement, we assessed and studied various dimensions of the C7 lateral mass, pedicles, and laminae in relevant sections.ResultsThe mean age of our patients was 49.5±16.1 years. We included 56 male and 44 female patients. The mean anteroposterior and mediolateral dimensions of the lateral mass were 11.38±1.76 and 12.91±1.82 mm, respectively. The mean length of the lateral mass screw (Magerl technique) was 12.17±1.9 mm; 92% of patients could accommodate a lateral mass screw at least 10-mm long (unicortical), whereas 48% could accommodate a screw (unicortical) longer than 12 mm. Foramen transversarium was found in 30.5% of lateral masses. The mean outer and inner cortical widths of the pedicles were 6.5±0.71 mm and 3.72±0.61 mm, respectively. Approximately 58% of pedicles could accommodate 3.5-mm screws (based on the inner cortical pedicle width). The outer cortical and inner cortical widths of the laminae were 6.21±1.2 mm and 3.23±0.9 mm, respectively. Subsequently, 37% of the laminae could accommodate 3.5-mm screws. The mean angle of intralaminar screw trajectory was 50.7°±5.1°, and the mean length of the intralaminar screw was 32.6±3.05 mm. In addition, 96.4% and 60.7% of male patients could accommodate lateral mass screws longer than 10 mm and 12 mm, respectively. However, only 86.4% and 31.8% of female patients could accommodate 10- and 12-mm long lateral mass screws, respectively. Furthermore, 75% of male patients and 36% of female patients had pedicles that could accommodate 3.5-mm diameter screws, and 48.2% of male patients had laminae that could accommodate 3.5-mm screws; however, only 22.7% of female patients could accommodate 3.5-mm laminar screws.Conclusions Based on our CT-guided morphometric analysis, 92% and 48% of Indian patients could accommodate at least 10- and 12-mm long lateral mass screws, and 58% of pedicles and 37% of laminae could accommodate 3.5-mm screws. Thus, lateral mass screws (between 10- and 12-mm long) seem to be the safest feasible option for C7 fixation. In case of the need for an alternative mode of stabilization (pedicle or intralaminar screw), particularly in female patients, careful preoperative planning with a CT scan is of utmost importance.

The importance of petrous apex and peri-carotid pneumatisation in subtotal petrosectomy and blind sac closure: a radiological study.

To ascertain in what proportion the vertical segment of the intratemporal carotid artery on its medial aspect anatomically separates the peri-tubal cells and Eustachian tube from the remainder of the pneumatised spaces of the temporal bone. A retrospective review was conducted of 222 adult and 29 paediatric consecutive computed tomography scans of petrous temporal bones from a single tertiary referral centre. In 96 per cent of temporal bones, the carotid artery formed a lateral barrier (with no communication pathway medially) between air spaces anterior and posterior to it. This equated to 94 per cent when chronic otitis media cases were excluded. The degree of separation of middle-ear air cells from the Eustachian tube or nasopharynx, and the relevant anatomy, are reviewed. This knowledge helps to optimise the outcome of subtotal petrosectomy and blind sac closure. The frequency and process of pneumatisation of the petrous apex, and its connections with the middle ear, have been radiologically confirmed.

CT predicts liver fibrosis: Prospective evaluation of morphology- and attenuation-based quantitative scores in routine portal venous abdominal scans.

ObjectivesOur aim was to prospectively determine whether quantitative computed tomography (CT) scores, consisting of simplified indices for liver remodeling and attenuation, may predict liver fibrosis in abdominal CT scans.Materials and methodsThis cross-sectional, prospective study was approved by the local IRB (Kantonale Ethikkommission Bern). Written informed consent was given from all patients undergoing study-MR exams. Between 02/16 and 05/17, four different liver fibrosis scores (CRL-R = caudate-right-lobe ratio, LIMV-, LIMA- and LIMVA-fibrosis score, with “LIM” for liver imaging morphology, “V” for liver vein diameter and “A” for attenuation) were calculated in 1534 consecutive abdominal CT scans, excluding patients with prior liver surgery and liver metastasis. Patients were invited to undergo magnetic resonance (MR) elastography as the non-invasive gold standard to evaluate liver fibrosis. MR elastography shear modulus ≥2.8 kPa was defined as beginning liver fibrosis, while ≥3.5 kPa was defined as significant liver fibrosis (which would correspond to fibrosis stage F2 or higher in histology). Cutoff values, sensitivities and specificities obtained from the receiver operating characteristics (ROC) analysis were then calculated in 141 patients who followed the invitation for MR elastography. To mitigate selection bias, prevalence was estimated in the screened total population (n = 1534) by applying the cutoff values with sensitivities and specificities calculated in the MR elastography sub-group. Positive predictive values (PPV) and negative predictive values (NPV) were then calculated.ResultsFibrosis scores including liver vein attenuation LIMA-FS and LIMVA-FS showed higher areas under the ROC curves (0.96–0.97) than CRL-R (0.82) to detect significant liver fibrosis, while LIMV-FS showed good performance as well (0.92). The prevalence-corrected PPV were 29% for CRL-R, 70% for LIMV-FS, 76% for LIMA-FS and 82% for LIMVA-FS.ConclusionCT fibrosis scores, notably LIMA-FS and LIMVA-FS, may predict significant liver fibrosis on routine abdominal CT scans.

Cross-Sectional Area Measurement of the Central Tarsometatarsal Articulation: A Review of Computed Tomography Scans

Currently, disagreement exists regarding the superior method for repairing a ligamentous Lisfranc injury regarding whether to use arthrodesis or open reduction internal fixation. The 2 procedures differ in the amount of articular cartilage destroyed. Arthrodesis removes all the articular cartilage, and open reduction internal fixation places transarticular screws, essentially destroying a portion of cartilage. We performed a review of 30 consecutive computed tomography scans that included both foot length and undamaged first, second, and third tarsometatarsal joints to quantify the amount of articular surface area destroyed by placement of standardized 4-mm diameter screws. Measurements were performed using a freeform tool. The calculated surface area of the screws was subtracted from the measured surface area of the joint to yield the amount of surface area occupied by the screws. Our results demonstrated that the average amount of articular surface area destroyed in the first, second, and third tarsometatarsal joints was 4.87%, 4.79%, and 4.86% respectively, with a standard deviation of <1% for each of the joints. Our results have demonstrated that screw placement accounts for only a small percentage of articular surface destroyed. They also showed that the articular surface damage was comparable among the first 3 tarsometatarsal joints. Additionally, our results were similar to the articular surface area calculated from cadaveric specimens in a previous biomechanical study, demonstrating that computed tomography can allow for reliable and accurate assessments of articular surface areas in the foot.

Computed Tomography Measurements as a Standard of Exophthalmos? Two-Dimensional Versus Three-Dimensional Techniques

ABSTRACTPurpose: To compare measurements of exophthalmos using two-dimensional (2D) and three-dimensional (3D) computed tomography (CT) methods.Methods: The CT data of 50 patients with thyroid eye disease were collected. The exophthalmos measurements were performed using both 2D and 3D methods. The protrusion of the globe center, the deviation angle of the ocular axis, and the distance between the globe center and the corneal apex were also recorded. The agreements between Hertel exophthalmometry and different CT measurements were analyzed, and the geometrical relationship between the protrusion of the corneal apex and globe center were analyzed.Results: The measurement agreement from consecutive CT scans was significantly better using the 3D method than the 2D method (p < 0.05). The difference in exophthalmos measurements between the 2D and 3D methods was 0.9 ± 1.2 mm (p < 0.05), and the 3D exophthalmos measurement was more consistent with Hertel exophthalmometry. The exophthalmos of the corneal apex and the globe center agreed with the geometrical formula well. The location error between the corneal apexes marked on the 2D and 3D images was correlated with the vertical deviation angle of the ocular axis (r = 0.516).Conclusion: The reliability of CT measurements performed using a 3D method was better than those obtained using a conventional 2D method. The 3D measurements were also more consistent with the exophthalmometry results. The exophthalmos of the globe center might be considered an important reference for patients with severe strabismus.