Computed Tomography Imaging Studies Research Articles

Implant-related artifacts around metallic and bio-integrative screws: a CT scan 3D Hounsfield unit assessment

Objective: To assess the degree of implant-related artifacts (IRA) around metallic and bio-integrative (BI) cannulated screws using Hounsfield units (HU) on computed tomography (CT). Our hypothesis was that BI implants would demonstrate significantly decreased IRA around the inserted screws. Methods: In this cadaveric CT imaging study, we used 2 below-knee specimens. Medial displacement calcaneal osteotomy was performed, and the specimens were fixed with either metallic or BI screws. HU values were measured over 4 different lines that crossed the osteotomy position. Results: The mean HU value was decreased in the BI implants compared to the metallic ones in 3 different positions: near the screw, directly over the screw, and inside the screw cannula. At the line placed 1 cm dorsal to the screw, the HU value for the metallic screw was lower than that for the BI screw. Conclusions: We found metallic implants to demonstrate significantly increased HU values in regions close to the implant and significantly decreased values 1 cm away from the implant, when compared to the BI screw. The decreased HU values 1 cm away from the implant could be due to a shielding effect of the surrounding bone, hindering the assessment of union and healing. BI implants represent an alternative to decrease these IRA effects. Level of Evidence III; Case-Control Study.

Computed tomography evaluation of proposed implant corridors in canine thoracic vertebrae.

Identify acceptable implant corridors in the normal canine thoracic vertebrae (T) from T1 to T9. Retrospective study. Computed tomographic (CT) studies of normal canine thoracic spines (n=39). CT imaging studies of normal T1-T9 canine spines were evaluated by five independent observers. Each identified a proposed corridor, measured the width, length, and angle off mid-sagittal that the corridor occupied. CT studies were from 39 dogs weighing 3.19-60 kg (mean 10.72, SD 9.9 kg). Vertebral corridors ranged in average width from 3.8 to 5.2 mm, the widest being located at T1. They ranged in average length from 13.3 to 17.5 mm, shortest being T1 and longest being T6. The angle of corridors varied the most between individual vertebrae at T1-T3. The average corridor angles were: T1=38°, T2=32°, T3=27°, T4=26°. T5-T9 angle ranged from 23° to 24°. The average dimensions of corridors measured in dogs weighing 3.1-60 kg were consistent with those of commercially available cortical screws and pins. Corridor trajectories identified in this population can be achieved from a dorsal approach between T5 and T9. A dorsal approach for implant placement would be challenging for T1-T4 due to the variability found in these vertebrae as well as regional anatomical constraints.

Nasal High Flow at 25 L/min or Expiratory Resistive Load Do Not Improve Regional Lung Function in Patients With COPD: A Functional CT Imaging Study.

BackgroundNasal high flow (NHF) is a non-invasive breathing therapy that is based on the delivery via a large-caliber nasal cannula of heated and humidified air at flow rates that exceed peak inspiratory flow. It is thought that positive airway pressure generated by NHF can help reduce gas trapping and improve regional lung ventilation. There are no data to confirm this hypothesis at flow rates applicable in stable chronic obstructive pulmonary disease (COPD) patients.MethodsIn this study, we used non-rigid registration of computed tomography (CT) images acquired at maximal expiration and inspiration to compute regional lung attenuation changes (ΔHU), and lung displacement (LD), indices of regional lung ventilation. Parametric response maps (Galban et al., 2012) were also computed in each experimental condition. Eight COPD patients were assessed at baseline (BL) and after 5 min of NHF and expiratory resistive loading (ERL).ResultsΔHU was: BL (median, IQR): 85 (67.2, 102.8); NHF: 90.7 (57.4, 97.6); ERL: 74.6 (46.4, 89.6) HU (p = 0.531); and LD: 27.8 (22.3, 39.3); 17.6 (15.4, 27.9); and 20.4 (16.6, 23.6) mm (p = 0.120) in the 3 conditions, respectively. No significant difference in trapping was observed. Respiratory rate significantly decreased with both treatments [BL: 17.3 (16.4, 18.9); NHF: 13.7; ERL: 11.4 (9.6, 13.2) bpm; and p < 0.001].ConclusionNeither NHF at 25 L/min nor ERL significantly improved the regional lung ventilation of stable COPD patients with gas trapping, based on functional lung CT imaging. Further study including more subjects is needed to assess the potential effect of NHF on regional lung function at higher flow rates.Clinical Trial Registrationwww.clinicaltrials.gov/under, identifier NCT03821311.

Differences in Temporal Volume between Males and Females and the Influence of Age and BMI: A Cross-Sectional CT-Imaging Study

The temple has been identified as one of the most compelling facial regions in which to seek aesthetic improvement-both locally and in the entire face-when injecting soft tissue fillers. The objective of this study is to identify influences of age, gender, and body mass index (BMI) on temporal parameters to better understand clinical observations and to identify optimal treatment strategies for treating temporal hollowing. The sample consisted of 28 male and 30 female individuals with a median age of 53 (34) years and a median BMI of 27.00 (6.94) kg/m2. The surface area of temporal skin, the surface area of temporal bones, and the temporal soft tissue volume were measured utilizing postprocessed computed tomography (CT) images via the Hausdorff minimal distance algorithm. Differences between the investigated participants related to age, BMI, and gender were calculated. Median skin surface area was greater in males compared with females 5,100.5 (708) mm2 versus 4,208.5 (893) mm2 (p < 0.001) as was the median bone surface area 5,329 (690) mm2 versus 4,477 (888) mm2 (p < 0.001). Males had on average 11.04 mL greater temporal soft tissue volume compared with age and BMI-matched females with p < 0.001. Comparing the volume between premenopausal versus postmenopausal females, the median temporal soft tissue volume was 46.63 mL (11.94) versus 40.32 mL (5.69) (p = 0.014). The results of this cross-sectional CT imaging study confirmed previous clinical and anatomical observations and added numerical evidence to those observations for a better clinical integration of the data.

Computerized Tomographic Patterns of Intracranial Tumors in Northwest Nigeria

Background: Brain tumors are among the most challenging disorders encountered worldwide. Early and accurate diagnosis is essential for the management of these tumors. Different patterns of distribution of intracranial tumors have been described in various regions of the world, with previous reports in Africa suggesting that brain tumors were uncommon. This relative rarity has been attributed to low detection due to lack of neurosurgical and advanced neuroimaging facilities previously, a limitation that has now been gradually surmounted with the establishment of neurosurgical and more advanced radiological facilities on the continent. Objectives: The objective of this study is to describe the current pattern of intracranial tumors on computed tomography (CT) scan seen in Ahmadu Bello University Teaching Hospital (ABUTH) Zaria, Northwest Nigeria. Methods: This is a retrospective study of CT images of 60 patients of all age groups diagnosed with brain tumors between January 2015 and December 2019. The CT scans of the brain were performed using General Electric Hi-Speed NX/i dual-slice CT scanner (Germany). The age, sex, diagnosis using the WHO histological, and the pattern on CT were recorded, and data were analyzed using Statistical Package for the Social Sciences version 22.0, ARMONK, NY, USA 2013. Only cases with conclusive histology diagnosis were analyzed. This study was approved by the Health Research Ethics Committee of the ABUTH, Zaria (approval Number ABUTH/HREC/M36/2015), on January 23, 2015, before commencement. Results: In the 60 cases of brain tumors studied, patients' age range was 6 months–65 years, with a peak in the fourth and fifth decades of life (accounting for 38.3%). The mean age was 33.04 years ± 17.73 standard deviation. There was equal occurrence among males and females. About 96.7% of the tumors were primary and 3.7% secondary tumors; meningioma (MEN) (45%) was the most common tumor seen. About 45% of the cases were extra-axial, while 55% were intra-axial. Most (81.67%) of the tumors were located in the supratentorial region, while 18.33% were infratentorial. Headache (75%) and visual impairment (53.3%) were the most frequent clinical presentations. Conclusion: MEN was the most common tumor type seen in this study. This corroborates most studies in Nigeria and other African countries but contradicts some studies among Caucasians that showed glioma to be more common. This affirms that racial factors and environmental influence could have significant effects on the pattern of diseases. The results of this study will provide useful data on the pattern of brain tumors in this environment.

Glenoid retroversion associates with deltoid muscle asymmetry in Walch B-type glenohumeral osteoarthritis

BackgroundThe etiologies of glenohumeral osteoarthritis (GHOA) and eccentric glenoid wear within GHOA are unknown, but muscular imbalance may play a role. The purpose of the present study was to determine the relationship between deltoid muscle area, GHOA, and eccentric glenoid wear. We hypothesized that patients with GHOA would have overall deltoid atrophy as compared with controls and that increasing posterior deltoid areas would associate with glenoid retroversion in the Walch B-type (eccentric) GHOA group.MethodsThe study was a retrospective review of computed tomography imaging studies. We included a control group of subjects without GHOA and a group of individuals with GHOA before undergoing total shoulder arthroplasty. We assigned Walch types via consensus. Cross-sectional area was measured for the anterior and posterior deltoid musculature demarcated via the scapular line, normalized to the total deltoid area. Absolute and normalized total, anterior, and posterior deltoid areas were compared between controls and the entire GHOA group. Normalized anterior and posterior deltoid areas were compared between Walch A-type and B-type GHOA patients within the GHOA group. Univariate linear regression was used to evaluate for an association between glenoid retroversion and normalized posterior deltoid areas in controls, Walch A-type, and Walch B-type patients. Multivariate linear regression analysis was used to evaluate the effects of normalized posterior deltoid area, age, sex, and height on glenoid retroversion within the Walch B-type subgroup.ResultsWe included 99 patients with GHOA and 47 controls. The control and GHOA patients did not differ in absolute deltoid areas (21.8 ± 8.8cm2 vs. 20.6 ± 7.9cm2; P = .488). Patients with GHOA had a statistically significant increase in normalized posterior deltoid area (0.50 ± 0.10 vs. 0.46 ± 0.10; P = .032) and a reciprocal decrease in normalized anterior deltoid area (0.50 ± 0.10 vs. 0.54 ± 0.10; P = .040) compared with controls. Walch A-type and B-type patients did not differ in normalized posterior deltoid areas (0.50 ± 0.11 vs. 0.50 ± 0.10; P = .780). Normalized posterior deltoid area positively associated with glenohumeral retroversion in Walch B-type GHOA (R2 = 0.102; P = .020), a relationship maintained in multivariate linear regression, using gender, age, and height as covariates (standardized beta = 0.309, P = .027).ConclusionGHOA is not associated with deltoid atrophy, calling into question the suggestion that periarticular muscular atrophy in GHOA is secondary to disuse. Increasing normalized posterior deltoid area associates with increased glenoid retroversion in patients with Walch B-type glenoid morphology. Muscular imbalance may play a role in the etiology or progression of the glenoid deformity observed in eccentric GHOA.

Dynamic evolution of osseous structure in osteonecrosis of the femoral head and dynamic collapse risks: a preliminary CT image study

BackgroundCollapse risk of osteonecrosis of the femoral head (ONFH) is estimated mainly based on static indicators, including lesion size and lesion location, but bone repairing is a dynamic process that lasts for years. The present study attempted to analyze the dynamic evolution of the osseous structure and its correlation with radiographic progression.MethodsThis retrospective study included 50 hips with ONFH from 50 patients. Participants were divided into the non-collapse group (n = 25) and the collapse group (n = 25). Original files of the initial computed tomography (CT) images were imported into imaging processing software for morphology analysis. The volume of sclerotic bone, the volume of soft tissue, and bone mineral density (BMD) were calculated. The linear correlations between the aforementioned indicators and the disease duration were estimated. The logistic regression analysis was conducted to evaluate the correlation of these indicators with the radiographic progression. Receiver operating characteristic (ROC) analysis was used to evaluate these indicators’ prediction performance.ResultsThe volume of sclerotic bone and the BMD grew with disease duration, but the volume of soft tissue decrease. The logistic regression analysis found that the volume of sclerotic bone and the BMD were statistically associated with radiographic progression. The ROC analysis found that the regression model, which integrated the volume of sclerotic bone and the BMD, had satisfactory performance in predicting radiographic progression.ConclusionThe present study suggested a dynamic evolution of the osseous structure and a dynamic variation trend of the collapse risk in ONFH. The volume of sclerotic bone and the BMD might serve as further prognostic indicators when estimating the collapse risk.

Potential Risk of Thoracic Aorta Injury from Excessively Long Right Pedicle Screws in Patients with Left Thoracic Scoliosis: A Computed Tomography Image Study

We sought to investigate the changed position of thoracic aorta relative to spine in patients with left thoracic scoliosis and to analyze the potential risks of thoracic aorta injury from pedicle screw insertion in these patients. Twenty patients with left thoracic scoliosis (Group A) and 15 normal subjects with a straight spine (Group B) were included. Axial computed tomography images from T5 to T12 of all these subjects were obtained to measure the aorta-vertebral angle. The percentages of thoracic aorta located anteriorly to the screw trajectory were calculated on both the left and right sides. The average aorta-vertebral angle in Group A was significantly larger than that in Group B at each level (P < 0.05) except T5. In Group A, both left and right pedicle screws might pose threats to the thoracic aorta. The percentages of aortas at risk from the right pedicle screw were high in the apical region. However, in Group B, only the left pedicle screw might pose threats to the aorta. No aorta was found to be at risk of injury from right pedicle screw insertion in Group B. The thoracic aorta often lies anteriorly to the left pedicle screw trajectory in normal subjects, especially in the lower thoracic region. However, the thoracic aorta moves to the right side in patients with left thoracic scoliosis, making a large proportion of patients at risk of injury from right pedicle screw insertion in the apical region.

Measurement of Scaphoid Bone Microarchitecture: A Computed Tomography Imaging Study and Implications for Screw Placement

High bone density and quality is associated with improved screw fixation in fracture fixation. The objective of this study was to assess bone density and quality in the proximal and distal scaphoid to determine optimum sites for placement of 2 screws in scaphoid fracture fixation. Twenty-nine cadaveric human scaphoid specimens were harvested and scanned using micro-computed tomography. Bone density (bone volume fraction) and bone quality (relative bone surface area, trabecular number, and trabecular thickness) were evaluated in 4 quadrants within each of the proximal and distal scaphoid. The proximal radial quadrant of the scaphoid had significantly greater bone volume than the distal ulnar (mean difference, 33.2%) and distal volar quadrants (mean difference, 32.3%). There was a significantly greater trabecular number in the proximal radial quadrant than in the distal ulnar (mean difference, 16.7%) and in the distal volar quadrants (mean difference, 15.9%) and between the proximal ulnar and the distal ulnar quadrants (mean difference, 12%). There was a significantly greater bone surface area in the proximal radial and distal radial quadrants than in the distal ulnar and distal volar quadrants. There were no significant differences in trabecular thickness between the 8 analyzed quadrants CONCLUSIONS: Although there are differences in bone volume, trabecular number, and bone surface area between the proximal pole of the scaphoid and that of the distal pole, there were no significant differences in the bone quality (trabecular thickness, trabecular number, and relative bone surface area) and density (bone volume fraction) between the 4 quadrants of the proximal or distal pole of the cadaveric scaphoids studied. Insertion of 2 headless compression screws can be determined by ease of surgical access and ease of screw positioning and not by differences in bone quality or density of the proximal or distal scaphoid.

Prevalence of pectus excavatum in an adult population-based cohort estimated from radiographic indices of chest wall shape.

Pectus excavatum is the most common chest wall skeletal deformity. Although commonly evaluated in adolescence, its prevalence in adults is unknown. Radiographic indices of chest wall shape were analyzed for participants of the first (n = 2687) and second (n = 1780) phases of the population-based Dallas Heart Study and compared to clinical cases of pectus (n = 297). Thoracic computed tomography imaging studies were examined to calculate the Haller index, a measure of thoracic axial shape, and the Correction index, which quantitates the posterior displacement of the sternum relative to the ribs. At the level of the superior xiphoid, 0.5%, 5% and 0.4% of adult Dallas Heart Study subjects have evidence of pectus excavatum using thresholds of Haller index >3.25, Correction index >10%, or both, respectively. Radiographic measures of pectus are more common in females than males and there is a greater prevalence of pectus in women than men. In the general population, the Haller and Correction indices are associated with height and weight, independent of age, gender, and ethnicity. Repeat imaging of a subset of subjects (n = 992) demonstrated decreases in the mean Haller and Correction indices over seven years, suggesting change to a more circular axial thorax, with less sternal depression, over time. To our knowledge, this is the first study estimating the prevalence of pectus in an unselected adult population. Despite the higher reported prevalence of pectus cases in adolescent boys, this study demonstrates a higher prevalence of radiographic indices of pectus in adult females.

Greenfield stainless steel vena cava filters on computed tomography follow-up

ObjectiveThe objective of this study was to evaluate complications of Greenfield (Boston Scientific, Marlborough, Mass) stainless steel inferior vena cava (IVC) filters on follow-up computed tomography (CT) imaging and to elucidate associated risk factors. MethodsNinety-three patients with CT studies obtained for other reasons after Greenfield IVC filter placement (2007-2014) were retrospectively studied. Greenfield filters were placed permanently in those with venous thromboembolism and an expected lifelong contraindication to anticoagulation or life expectancy <6 months. Patients' demographic data, procedural characteristics, and imaging studies were reviewed and factors associated with perforation rates were analyzed. ResultsA total of 190 follow-up CT imaging studies were available for review. In total, filter-associated IVC thrombus (n = 10 [10.7%]) and pulmonary embolism breakthrough (n = 4 [4.3%)] were documented by contrast-enhanced CT. Perforation was evident in 18 patients (19.4%) with an average indwelling time of 256 days. No symptomatic perforation and no strut fracture were documented. There was no significant difference in perforation rate with respect to age of the patient (P = .61), sex (P = 1.00), or history of malignant disease (P = .40). The filter perforation rate and number of perforating struts were significantly higher in patients with longer indwelling time (>90 days) than in patients with shorter indwelling time (<90 days; P < .01). Caval cross-sectional areas of patients who experienced IVC filter perforations at >90 days were significantly smaller than those of nonperforated patients (284 vs 358 mm2; P < .01). ConclusionsStainless steel Greenfield filters remain a relatively safe option for patients requiring permanent mechanical filtration.

Relationship of the Exiting Nerve Root and Superior Articular Process in Kambin's Triangle: Assessment of Lumbar Anatomy Using Cadavers and Computed Tomography Imaging

Percutaneous transforaminal endoscopic diskectomy has been a major treatment for lumbar disk herniation. However, damage to exiting nerve roots is one of the most severe complications in this surgery. In this paper, the relationship of the exiting nerve root and the superior articular process in Kambin's triangle of the lumbar intervertebral foramen was assessed using cadavers and computed tomography (CT) imaging. The anatomic relationship between the exiting nerve root and the superior articular process in Kambin's triangle of the intervertebral foramen was investigated on 6 cadavers. The distance between the exiting nerve and the superior articular process of the L1-2 to L5-S1 intervertebral foramina was measured using multiplane reconstruction. The bone-nerve space between the exiting nerve root and the superior articular process in Kambin's triangle was quite narrow both in cadaver and CT imaging study. The distance of the L5-S1 intervertebral foramen was the greatest, which was no more than 5.77 ± 0.56 mm. The distances increased gradually from the tip to the root, and the distances between the root and the tip were 0.91 ± 0.31 to 1.86 ± 0.57 mm, which took on a trapezoid shape that was relatively narrow at the proximal end and wider at the distal end. The bone-nerve space between the exiting nerve root and the superior articular process in Kambin's triangle of the lumbar intervertebral foramen wasexceedingly narrow. It is necessary to perform a foraminoplasty to enlarge the working space and decrease the possibility of injury to the exiting nerve root.

99mTc-D(RGD): molecular imaging probe for diagnosis of αvβ3-positive tumors.

Arginine-glycine-aspartic acid (RGD) peptide with its specific binding affinity to integrin αvβ3, is widely investigated for the development of molecular imaging probes for diagnosis of αvβ3-positive tumors. The aim of this work was to evaluate the ability of Tc- HYNIC-D(RGD), a novel retro-inverso peptidomimetic derivative for U87MG tumor (αvβ3-positive) imaging. HYNIC-D(RGD) labeled with Tc using tricine/EDDA as an exchange coligands. Single-photon emission computed tomography imaging and biodistribution study were performed in nude mice bearing U87MG xenograft tumor. The labeling yield was >95%. The radiopeptide showed high uptake value in the U87MG tumor relative to muscle after 2 hours (1.43 ± 0.05 vs. 0.22 ± 0.11 %ID/g). The tumor/muscle ratio was 6.5. Blocking experiment showed specific binding towards tumor. Single-photon emission computed tomography imaging study revealed that radiopeptide had prominent uptake in U87MG tumor. The novel Tc HYNIC- D(RGD) was demonstrated to be a useful radiotracer for the assessment of αvβ3-positive tumor in animal model. Therefore, further clinical and preclinical studies are required.

Risk of contrast extravasation with vascular access in computed tomography.

Diagnostic computed tomography (CT) imaging, utilizing intravenous (IV) contrast administration, has become increasingly common. Potential IV contrast-associated complications include local skin and soft tissue reactions due to extravasation. The goal of this study is to describe the risk of contrast extravasation based on IV catheter anatomic location in patients receiving contrast-enhanced CT imaging. The study was conducted as a retrospective cohort study of patients receiving contrast-enhanced CT imaging performed over a 26-month period at a single institution. The rate of contrast extravasation was calculated by IV catheter vessel anatomic location and compared by relative risk (RR) and absolute risk reduction (ARR). Of 17,767 contrast administrations for CT imaging studies performed, 14,558 met study inclusion criteria. Forty-nine (0.34%) extravasation events were identified. Forty-one (0.28%, 95% CI 0.21-0.39%) extravasation events were observed in 14,275 peripheral IV catheters placed in a non-upper arm location. Eight (2.8%, 95% CI 1.3-5.3%) extravasation events were observed in 283 IV catheters placed, most commonly with point-of-care ultrasound (POCUS) guidance, in upper arm vessels (RR 10.1, 95% CI 4.69-21.8). Non-upper arm located IV catheters were associated with an ARR of 2.54% (95% CI 0.61-4.47%) when compared to upper arm catheters. IV catheter placement in upper arm vessels is associated with a relatively minimal increase in extravasation risk when compared to catheters placed in a non-upper arm location. In patients without alternative available peripheral vascular access, POCUS-guided upper arm IV cannulation may be an appropriate approach.

Value of Lumbar Lordosis and Back Pain in the Female Population Over 50 Years of Age

Introduction: In highly developed societies, back pain is a fairly common phenomenon, and its causes are usually multifactorial. Backaches can be caused by improper body posture, anatomical conditions, overloads, inflammation and many other factors. Changes in the shape of the spine in the sagittal plane, such as shallowing or deepening physiological curves translate into a change in the distribution of forces acting on individual parts of the spine, overloading the axial organ of movement. Aim: The aim of the study was to determine the relationship between the individual variants of lordosis (hypolordosis, hyperlordosis, norm) and pain experienced by women in the area of the lumbosacral spine (L/S). Material and Methods: The study group was a population of women over 50 (n = 277), divided into three subgroups, i.e. women with: normal, shallow and deepened lordosis, evaluated in the sagittal view in computed tomography imaging studies. Results: Deepened lordosis is associated with the highest BMI = 27.30 but a rather low average pain value (VAS = 4.60), which approximately corresponded to the severity of the discomfort in the group of women with normal lumbar lordosis. Shallow lordosis correlates with a lower BMI = 26.60 and the highest level of pain (VAS = 6.67). When the lordosis angle was normal, the pain was the lowest. Conclusions: The size of the lordosis angle may be a predictor of the occurrence of pain. A larger lumbar lordosis angle correlates with a higher body weight but pain in this group of women occurs with similar intensity as in the group of women with a normal lumbar lordosis angle.The research results indicate a strong correlation (p &lt;0.0229) between shallow lordosis and the severity of pain experienced by the examined women, which should be taken into account when planning treatment.

X-ray and Computed Tomography Scan-Based Morphometric Analysis of Skull Baselines in Indian Population.

Introduction:The study aims at providing an overview of morphometric measurements of the skull baselines in normal Indian population and compares these dimensions with those of other races and ethnicities. This study will help in defining “normal” baseline values for Indian population. It will also compare dimensions as measured on X-ray and computed tomography (CT) scan to assess the reliability of X-ray as a diagnostic modality for the assessment of the skull baselines in Indian population.Materials and Methods:Retrospective study with a sample size of 116 patients and duration of 30 months.Results:The mean value for distance between dens tip and Chamberlain line on CT was 0.498 mm and on X-ray was 0.528 mm and for the distance between dens tip and McGregor line on CT was 0.213 mm and on X-ray was 0.228 mm. The mean distance between the dens tip and McRae line was 4.67 1.69 mm on CT scan and 4.7 1.76 mm on X-ray.Conclusion:There was not a single patient in whom the dens tip crossed the McRae line. Any protrusion of the dens tip beyond the foramen magnum is abnormal. Hence, the McRae line is easiest to understand and remember. Furthermore, the Chamberlain and McGregor lines rely on identifying the hard palate, which may not be included in routine X-ray, CT, and magnetic resonance imaging studies depend on the field of view. Hence, we recommend the use of McRae line for screening purposes while evaluating pathologies of the craniovertebral junction. X-ray is a reliable diagnostic technique for assessing morphometry of the skull baselines in an emergency or rural setting if facility for CT scan is not available.

Hepatic pathology in patients after Fontan operation: A computed tomography imaging study.

Hepatic dysfunction is an important long-term complication in Fontan patients. The purpose of this study was to evaluate the hepatic computed tomography (CT) findings after Fontan surgery and identify their association with clinical parameters. This study recruited 43 patients (23 male and 20 female patients aged 15.3 ± 6.8 years), who underwent Fontan surgery. Medical records were reviewed to collect their age, sex, congenital heart disease type, date of Fontan surgery, laboratory data, and hepatic CT findings. The relationship between hepatic findings and clinical parameters was analyzed. The follow-up duration was 6.8 ± 4.1 years. Abnormal hepatic parenchymal enhancement was observed in 77% of the patients, with mild degree in 18, moderate degree in 10, and severe degree in 5 patients. According to the univariate analysis, risk factors for hepatic parenchymal enhancement were follow-up duration (odds ratio [OR]: 1.354 [95% confidence interval (CI): 1.024-2.078]; p = 0.042), hypoplastic left heart syndrome (HLHS) (OR: 3.262 [95% CI: 1.145-5.628]; p = 0.002), mean pulmonary artery pressure (OR: 1.598 [95% CI: 1.089-2.132]; p = 0.026), pulmonary vascular resistance index (OR: 1.263 [95% CI: 1.068-1.245]; p = 0.032), and brain natriuretic peptide (OR: 1.956 [95% CI: 1.085-2.673]; p = 0.045). According to the multivariate analysis, only HLHS (OR: 3.856 [95% CI: 1.389-5.863]; p = 0.001), mean pulmonary artery pressure (OR: 1.846 [95% CI: 1.362-2.549]; p = 0.015), and pulmonary vascular resistance index (OR: 1.185 [95% CI: 1.042-1.736]; p = 0.047) were significant risk factors for abnormal parenchymal enhancement. Abnormal hepatic parenchymal enhancement detected through CT is common in Fontan patients. Regular liver function test in conjunction with imaging studies may be considered when following up Fontan patients.

Effects of Allopurinol Dose Escalation on Bone Erosion and Urate Volume in Gout: A Dual-Energy Computed Tomography Imaging Study Within a Randomized, Controlled Trial.

To examine whether allopurinol dose escalation to achieve serum urate (SU) target can influence bone erosion or monosodium urate (MSU) crystal deposition, as measured by dual-energy computed tomography (DECT) in patients with gout. We conducted an imaging study of a 2-year randomized clinical trial that compared immediate allopurinol dose escalation to SU target with conventional dosing for 1 year followed by dose escalation to target, in gout patients who were receiving allopurinol and who had an SU level of ≥0.36 mmoles/liter. DECT scans of feet and radiographs of hands and feet were obtained at baseline, year 1, and year 2 visits. DECT scans were scored for bone erosion and urate volume. Paired imaging data were available for 87 patients (42 in the dose-escalation group and 45 in the control group). At year 2, the progression in the CT erosion score was higher in the control group than in the dose-escalation group (+7.8% versus +1.4%; P = 0.015). Changes in plain radiography erosion or narrowing scores did not differ between groups. Reductions in DECT urate volume were observed in both groups. At year 2, patients in the control group who had an SU level of <0.36 mmoles/liter and patients in the dose-escalation group had reduced DECT urate volume (-27.6 to -28.3%), whereas reduction in DECT urate volume was not observed in control group patients with an SU level of ≥0.36 mmoles/liter (+1.5%) (P = 0.023). These findings provide evidence that long-term urate-lowering therapy using a treat-to-SU-target strategy can influence structural damage and reduce urate crystal deposition in gout.

A prospective observational study on adverse drug reactions of iohexol contrast media in computed tomography imaging studies

Background: Iohexol is widely used radiocontrast media in the radiology departments for the diagnostic imaging purpose. As very few studies are carried out focusing on safety profiles of this contrast media. This study was conducted to know the profile of adverse drug reactions (ADRs) induced by Iohexol in patients who are undergoing the contrast-enhanced computed tomography (CECT) examination.Methods: Total 106 patients from CT unit of radiology department were observed for adverse drug reactions from Iohexol contrast media in 2 months duration. Acute ADRs were recorded immediately after contrast media administration by observation and personal interviews and delayed ADRs are recorded by follow up after 24hrs.Results: Total 23 out of 106 patients who had undergone CT imaging investigations by Iohexol contrast media had developed ADRs. Total 29 ADRs were developed in 23 patients. Out of these, 22 ADRs were acute and 7 ADRs were delayed reactions. All acute ADRs were of “probable” category and all delayed ADRs were of “possible” category according to WHO-UMC and Naranjo’s causality assessment scales. All ADRs were at Level-1 according to Modified Hartwig and Siegel severity scale. Preventability assessment of ADRs using Modified Schumock and Thornton preventability scale showed that all the ADRs were of “not preventable” class. All 29 ADRs were of TYPE U (Unclassified) as per the Wills and Brown method.Conclusions: All reactions are physiologic and are mild in nature. No life-threatening reactions are observed during the entire study period. Development of ADRs in female patients seen higher than male patients. So, this population requires a special attention for any serious contrast media reactions.

A case report: multiple right ventricular diverticula with constrictive pericarditis and right heart failure.

BackgroundRight ventricular diverticula (RVD) are very rare congenital anomalies and their association with constrictive pericarditis is even rarer. So far, only one case has been published in literature.Case summaryWe report a case of multiple congenital RVD with constrictive pericarditis and right heart failure which was incidentally identified on surveillance computed tomography (CT) for abdominal lymphangioma. Interval CT, echocardiography, and cardiac magnetic resonance imaging (CMR) studies were performed and reviewed. Computed tomography abdomen showed hepatic congestion with features of portal hypertension, increasing size of the RVD on review of serial CTs, and eccentric foci of pericardial calcification. Echocardiography performed for breathlessness demonstrated supranormal early diastolic tissue velocities with average of 19.8 cms−1 and a septal bounce phenomenon on m-mode imaging suggesting constrictive physiology, which triggered a CMR referral. Cardiac magnetic resonance imaging HASTE and right ventricular (RV) outflow tract imaging showed four outpouchings along RV free wall, the largest measuring 4.5 × 2 cm with a sizeable neck. These outpouchings displayed a trabecular network and/or were contractile aiding the diagnosis of diverticula as opposed to aneurysms. Right ventricular function was moderately compromised, whereas left ventricular function was preserved.DiscussionRight ventricular diverticula can be associated with, and potentially be causative of, pericardial thickening and calcification eventually leading to constrictive pericarditis and heart failure.