Role of multidetector computed tomography (MDCT) in diagnosis of subhepatic appendicitis

Background

Acute appendicitis is a common surgical condition that is usually managed with early surgery, and is associated with low morbidity and mortality. However, some patients may have atypical symptoms and physical findings that may lead to a delay in diagnosis and increased complications.Ascending subhepatic appendicitis presenting with right upper abdominal pain may be clinically indistinguishable from acute pathology in the gallbladder, liver, biliary tree, right kidney and right urinary tract.

Aim of the work

To study the role of multidetector computed tomography in diagnosis of subhepatic appendicitis.

Subjects & methods

In the current study, we included fifteen patients diagnosed radiologically and confirmed surgically as subhepatic appendicitis.Ultrasonography followed by multidetector computed tomographic examination were performed to all patients before surgery.

Results

The clinical diagnosis of the patients included in this study at presentation was acute cholecystitis in four patients, pyelonephritis in three, and ureteric colic in three. Five patients were referred with uncertain diagnosis.The presence of subhepatic appendicitis was confirmed sonographically only in two patients. Computed tomography (CT) identified correctly subhepatic appendicitis in all cases.

Conclusion

Our study indicates the usefulness of multidetector CT in diagnosing atypical ascending subhepatic appendicitis.     

Role of multidetector computed tomography (MDCT) in diagnosis and staging of gall bladder carcinoma

Background

Carcinoma of the gall bladder is the fifth most common malignancy of the gastrointestinal tract after colorectal, pancreatic, gastric and esophageal carcinomas.

Aim of the work

To study the role of multidetector computed tomography in the diagnosis and staging of gall bladder carcinoma.

Subjects and methods

This study included twenty-five patients presented to us during the period from June 2011 till May 2012 and were diagnosed radiologically by multidetector computed tomography as carcinoma of the gall bladder and the diagnosis was confirmed histopathologically. All the patients were subjected to ultrasonography followed by multidetector computed tomographic imaging using triphasic examination technique.

Results

Among the twenty-five patients included in this study there were fifteen females and ten males. Their ages ranged from 50 to 70 years old (average 60 years). All the patients were radiologically diagnosed as gall bladder carcinoma based on the multidetector computed tomographic findings. Infiltrating masses were detected in fifteen patients (60%), Intraluminal polypoidal masses were detected in nine patients (36%) while one patient (4%) presented with mural thickening of the gall bladder wall.

Conclusion

We conclude that multidetector CT is the diagnostic tool of choice in the detection and staging of gall bladder carcinoma.     

Prognostic value of computed tomography pulmonary angiography indices in patients with cancer-related pulmonary embolism: Data from a multicenter cohort study

ObjectiveTo analyze the prognostic value of pulmonary artery obstruction versus right-ventricle (RV) dysfunction radiologic indices in cancer-related pulmonary embolism (PE).MethodsWe enrolled 303 consecutive patients with paraneoplastic PE, evaluated by computed tomography pulmonary angiography (CTPA) between 2013 and 2014. The primary outcome measure was serious complications at 15 days. Multivariate analyses were conducted by using binary logistic and robust regressions. Radiological features such as the Qanadli index (QI) and RV dysfunction signs were analyzed with Spearman’s partial rank correlations.ResultsRV diameter was the only radiological variable associated with an adverse outcome. Subjects with enlarged RV (diameter > 45 mm) had more 15-day complications (58% versus 40%, p = 0.001). The QI correlated with the RV diameter (r = 0.28, p < 0.001), left ventricle diameter (r = −0.19, p < 0.001), right ventricular-to-left ventricular diameter ratio (r = 0.39, p < 0.001), pulmonary artery diameter (r = 0.22, p < 0.001), and pulmonary artery/ascending aorta ratio (r = 0.27, p < 0.001). A QI ≥ 50% was only associated with 15-day complications in subjects with enlarged RV, inverted intraventricular septum, or chronic cardiopulmonary diseases. The central or peripheral PE location did not affect the correlations among radiological variables and was not associated with clinical outcomes.ConclusionsRight ventricular dysfunction signs in CTPA are more useful than QI in predicting cancer-related PE outcome.     

Multislice computed tomography perfusion imaging for visualization of acute pulmonary embolism: animal experience

The purpose of our animal study was to evaluate a new computed tomography (CT) subtraction technique for visualization of perfusion defects within the lung parenchyma in subsegmental pulmonary embolism (PE). Seven healthy pigs were entered into a prospective trial. Acute PE was artificially induced by fresh clot material prior to the CT scans. Within a single breath-hold, whole thorax CT scans were performed with a 16-slice multidetector-row CT scanner (SOMATOM Sensation 16; Siemens, Forchheim, Germany) before and after intravenous application of 80 ml of contrast medium with a flow rate of 4 ml/s, followed by a saline chaser. The scan parameters were 120 kV and 100 mAs_eff, using a thin collimation of 16×0.75 mm and a table speed/rotation of 15–18 mm (pitch, 1.25–1.5; rotation time, 0.5 s). Axial source images were reconstructed with an effective slice thickness of 1 mm (overlap, 30%). A new automatic subtraction technique was used. After 3D segmentation of the lungs in the plain and contrast-enhanced series, threshold-based extraction of major airways and vascular structures in the contrast images was performed. This segmentation was repeated in the plain CT images segmenting the same number of vessels and airways as in the contrast images. Both scans were registered onto each other using nonrigid registration. After registration both image sets were filtered in a nonlinear fashion excluding segmented airways and vessels. After subtracting the plain CT data from the contrast data the resulting enhancement images were color-encoded and overlaid onto the contrast-enhanced CT angiography (CTA) images. This color-encoded combined display of parenchymal enhancement of the lungs was evaluated interactively on a workstation (Leonardo, Siemens) in axial, coronal and sagittal plane orientations. Axial contrast-enhanced CTA images were rated first, followed by an analysis of the combination images. Finally, CTA images were reread focusing on areas with perfusion deficits indicating PE on the color-coded enhancement display. Subtraction was feasible for all seven studies. In one animal, opacification of the pulmonary arteries was suboptimal owing to heart insufficiency. In the remaining six pigs, a total of 37 perfusion defects were clearly assessable downstream of occluded subsegmental arteries, showing lower or missing enhancement compared with normally perfused lung parenchyma. Indeterminate findings from CTA showed typical PE perfusion defects in four out of six cases on CT subtraction. Additionally, 22 peripheral triangular-shaped enhancement defects were delineated. Nine of these findings were reclassified as definitely being caused by PE on second reading of the CTA data sets. Our initial results have shown that this new subtraction technique for perfusion imaging of PE is feasible, using routine contrast delivery. Dedicated examination protocols are mandatory for adequate opacification of the pulmonary arteries and for optimization of data sets for subsequent subtraction. Perfusion imaging allows a comprehensive assessment of morphology and function, providing more accurate information on acute PE.This paper contains data on behalf of the Amersham Health Research Fellowship Grant, ECR 2003.     

Multi-detector computed tomography (MDCT) imaging of cardiovascular effects of pulmonary embolism: What the radiologists need to know

Background

Patients with pulmonary embolism have high mortality and morbidity rate due to right heart failure and circulatory collapse leading to sudden death. Multi-detector computed tomography MDCT can efficiently evaluate the cardiovascular factors related to pulmonary embolism.

Logistic regression model for identification of right ventricular dysfunction in patients with acute pulmonary embolism by means of computed tomography

Purpose

Diagnosis of right ventricular dysfunction in patients with acute pulmonary embolism (PE) is known to be associated with increased risk of mortality. The aim of the study was to calculate a logistic regression model for reliable identification of right ventricular dysfunction (RVD) in patients diagnosed with computed tomography pulmonary angiography.

Material and methods

Ninety-seven consecutive patients with acute pulmonary embolism were divided into groups with and without RVD basing upon echocardiographic measurement of pulmonary artery systolic pressure (PASP). PE severity was graded with the pulmonary obstruction score. CT measurements of heart chambers and mediastinal vessels were performed; position of interventricular septum and presence of contrast reflux into the inferior vena cava were also recorded. The logistic regression model was prepared by means of stepwise logistic regression.

Results

Among the used parameters, the final model consisted of pulmonary obstruction score, short axis diameter of right ventricle and diameter of inferior vena cava. The calculated model is characterized by 79% sensitivity and 81% specificity, and its performance was significantly better than single CT-based measurements.

Conclusion

Logistic regression model identifies RVD significantly better, than single CT-based measurements.     

Gastrointestinal stromal tumors (GISTs): Diagnostic value of multi-detector computed tomography

Background

GISTs are considered the commonest mesenchymal neoplasms of the GIT originating from the gastrointestinal tract, mesentery, omentum, or retroperitoneum. They arise within the gut musculosa having exophytic growth pattern. They characteristically have hemorrhage, necrosis, or cyst formation that appears as focal areas of low attenuation on computed tomographic images.With multidetector CT (MDCT) capabilities, the exact origin of the GIST can be easily confirmed to differentiate it from other mesenchymal origin tumors.

Materials and methods

Retrospective search for GIST cases in the digital archives of our institute, during a 15 months duration (April 2010 to July 2011). Workstation reviewing of their imaging features.

Results

This study included 24 pathologically proved GISTs (12 gastric, 8 small intestinal, two colonic, one mesenteric and one anorectal) demonstrating the radiologic features of GISTs depending on tumor size and organ of origin.

Conclusion

MDCT with its multiplanar capabilities and isotropic z-axis resolution allows the radiologist to examine the detailed relation of the mass to the surrounding bowel wall, vessels and other structures. It also helps to map the vascular pedicle in cases of hypervascular GIST’s, which may be crucial for trans-catheter embolization in cases presenting with acute gastrointestinal bleeding.     

Age-related incidence of pulmonary embolism and additional pathologic findings detected by computed tomography pulmonary angiography

Objective

To compare the incidence of pulmonary embolism (PE) and additional pathologic findings (APF) detected by computed tomography pulmonary angiography (CTPA) according to different age-groups.

Materials and methods

1353 consecutive CTPA cases for suspected PE were retrospectively reviewed. Patients were divided into seven age groups: ≤29, 30–39, 40–49, 50–59, 60–69, 70–79 and ≥80 years. Differences between the groups were tested using Fisher's exact or chi-square test. A p-value < 0.0024 indicated statistical significance when Bonferroni correction was used.

Results

Incidence rates of PE ranged from 11.4% to 25.4% in different age groups. The three main APF were pleural effusion, pneumonia and pulmonary nodules. No significant difference was found between the incidences of PE in different age groups. Furthermore, APF in different age groups revealed no significant differences (all p-values > 0.0024).

Conclusion

The incidences of PE and APF detected by CTPA reveal no significant differences between various age groups.     

Assessment of coronary calcification using calibrated mass score with two different multidetector computed tomography scanners in the Copenhagen General Population Study

ObjectivePopulation studies have shown coronary calcium score to improve risk stratification in subjects suspected for cardiovascular disease. The aim of this work was to assess the validity of multidetector computed tomography (MDCT) for measurement of calibrated mass scores (MS) in a phantom study, and to investigate inter-scanner variability for MS and Agaston score (AS) recorded in a population study on two different high-end MDCT scanners.Materials and methodsA calcium phantom was scanned by a first (A) and second (B) generation 320-MDCT. MS was measured for each calcium deposit from repeated measurements in each scanner and compared to known physical phantom mass. Random samples of human subjects from the Copenhagen General Population Study were scanned with scanner A (N = 254) and scanner B (N = 253) where MS and AS distributions of these two groups were compared.ResultsThe mean total MS of the phantom was 32.9 ± 0.8 mg and 33.1 ± 0.9 mg (p = 0.43) assessed by scanner A and B respectively – the physical calcium mass was 34.0 mg. Correlation between measured MS and physical calcium mass was R² = 0.99 in both scanners. In the population study the median total MS was 16.8 mg (interquartile range (IQR): 3.5–81.1) and 15.8 mg (IQR: 3.8–63.4) in scanner A and B (p = 0.88). The corresponding median total AS were 92 (IQR: 23–471) and 89 (IQR: 40–384) (p = 0.64).ConclusionCalibrated calcium mass score may be assessed with very high accuracy in a calcium phantom by different generations of 320-MDCT scanners. In population studies, it appears acceptable to pool calcium scores acquired on different 320-MDCT scanners.     

Pulmonary embolism during venography: Report of a rare complication

Fortuitous radiologic documentation of a migrating thrombus during phlebography resulting in massive pulmonary embolus and cardiopulmonary collapse is demonstrated. This is a rare occurrence that has been infrequently documented and published.     

Assessment of major aortopulmonary collateral arteries with multidetector-row computed tomography

Multidetector-row computed tomography (MDCT) studies were performed in three adult patients with pulmonary atresia with a ventricular septal defect. In all patients, the native pulmonary arteries were absent, and the pulmonary circulation was totally supplied by major aortopulmonary collateral arteries (MAPCAs). MDCT studies with 1-mm collimation provided detailed information on MAPCAs and bronchial collaterals, such as the numbers and sites of origin, their varying diameters, their courses, and the areas of the lungs they supply. MDCT studies may provide an efficient road map for safe and successful selective catheterization and may substitute for conventional angiography in patients with considerable risks.     

Evaluation of pulmonary changes due to biomass fuels using high-resolution computed tomography

Biomass fuels are frequently used in rural areas of the world for cooking and heating frequently. It has been reported that the use of these fuels causes hazardous effects on the lungs. In this study, we evaluated the pulmonary changes due to the use of biomass fuels in a female population that lives in our territory by high-resolution computed tomography (HRCT). The study analyzed three groups of women. The first group comprised those subjects who were exposed to biomass without respiratory symptoms (group 1; n=32). The second group comprised those individuals that were exposed to biomass and showed respiratory symptoms, such as cough, sputum production, and dyspnea (group 2; n=30). The third group was composed of women who were not exposed to biomass and also had no respiratory symptoms (group 3; n=30). Women with a history of concomitant pulmonary diseases were excluded from the study. All groups were examined with HRCT. Groups 1 and 2 (individuals exposed to biomass fuels) had more pathologic findings than group 3 (not exposed to biomass fuels). Ground-glass appearance was seen in 71.9% in group 1, 23.3% in group 2, and 3.3% in group 3. The difference between the groups was statistically significant (p<0.05). Fibrotic bands were seen 50% in group 1, 63.3% in group 2, and only 6.7% in group 3 (p<0.001). Exposure to biomass fuels was the cause or predisposing factor for many pulmonary diseases, ranging from chronic bronchitis to diffuse lung diseases. We believe that these pathological changes due to biomass fuels can be detected earlier by HRCT and the diseases might be prevented or treated earlier.     

Spatial domain image filtering in computed tomography: feasibility study in pulmonary embolism

Our objective was to evaluate the clinical feasibility of spatial domain filtering as an alternative to additional image reconstruction using different kernels in chest CT. Spatial domain filtering generates smooth images from sharp images and thus avoids the need for additional reconstructions when two sets of images are desired. Forty adult patients with clinical suspicion of pulmonary embolism were examined utilizing multi-slice CT (Somatom Volume Zoom, Siemens, Germany). Derived from thin collimated source images (100 mAs, collimation 4×1 mm, rotation time 0.5 s, table speed 7 mm/rotation), two sets of images [effective slice thickness (S_eff) 5 mm, reconstruction increment (RI) 5 mm) were generated using lung (Siemens B50) and soft tissue (Siemens B30) kernels. Additionally, B50 images were filtered in the spatial domain, producing images largely equivalent to B30 images. Firstly, diagnostic accuracy was assessed on spatial domain filtered images regarding central, segmental, and subsegmental pulmonary embolism. In a second step, diagnostic accuracy was assessed for the initially reconstructed B30 images. The results were compared with thin axial slices from the same data set, which were considered as the gold standard in this respect (S_eff 1.25 mm, RI 0.8 mm; B30). Initially reconstructed B30 slices and secondary filtered images were rated for subjective image quality, using a five-point scale (1=excellent, 2=good, 3=moderate, 4=poor, 5=non-diagnostic). Finally, quantitative measurements were assessed using the region of interest (ROI) methodology. In 20 patients pulmonary embolism was proven. Five-millimeter images revealed 10 of 10 central emboli, 18 of 19 segmental thrombi, and 18 of 20 emboli on the subsegmental level. Pulmonary embolism was excluded in 18 of 20 subjects, and in 2 patients a false-positive result was obtained in subsegmental arteries. These findings were concordant for reconstructed and filtered images. Quantitative density measurements provided comparable Hounsfield units in this respect. Subjective gradings of image quality, based on soft tissue settings, were 1.30 (±0.61) for reconstructed slices vs 1.35 (±0.62) for filtered images (weighted kappa coefficient 0.6117; 95% confidence intervals 0.3298–0.8935). Spatial domain filtering has proved to be feasible. Compared with conventional soft tissue reconstructions for central, segmental, and subsegmental pulmonary embolism, no significant difference in the diagnostic value of spatial domain filtered images was found. Online modifications of image sharpness and pixel noise in real time leads to a considerable reduction of processing time and cost saving for storage of CT images. Despite different data processing methods, thin effective slice thicknesses and overlapping reconstruction increments are mandatory for detailed CT analysis of pulmonary embolism on the segmental and subsegmental level. Electronic Publication     

64层CT心电门控血管造影对急性肺栓塞右室功能的评价

目的：评价64层CT心电门控肺动脉造影（CTPA）对急性肺栓塞右室功能的价值。方法：回顾性分析64层CT心电门控CTPA且影像质量良好的患者共45例,所有患者均同时进行了常规CTPA。对常规CTPA患者,测量横断位、四腔心左右室最大短轴内径。对心电门控CTPA患者,测量舒张末期和收缩末期心室最大内径,并计算左、右室舒张末期和收缩末期容积。然后对阳性组与阴性组之间右心功能各组参数进行独立样本t检验,并对中央型、周围型及阴性组之间参数进行方差分析或非参数检验。结果：45例患者中,阳性30例,其中中央型20例、周围型10例。对于阴性组与阳性组,右室收缩末期容积（P=0.02）、每搏输出量（P=0.015）及射血分数（P=0.01）在两组之间的差异有统计学意义,右室/左室（RV/LV）收缩末期容积比在两组之间有统计学差异（P=0.005）。对于中央型、周围型与阴性组,右室每搏输出量、射血分数在中央型与阴性组之间以及周围型与阴性组之间均有统计学差异（P〈0.05或P〈0.01）。RV/LV容积比在中央型与阴性组之间,以及收缩末期中央型与周围型之间均有统计学差异（P〈0.05）。右室内径及RV/LV内径比在阴性与阳性组之间无统计学差异,但RV/LV内径比在中央型与阴性组之间（P〈0.05）或周围型之间（P〈0.01）有统计学差异。结论：64层CT心电门控肺动脉造影对评价右室功能有一定的价值。     

Giant aneurysm of the right internal carotid artery in an 8-month-old child presenting with a persistent red eye

SummaryChildhood intracranial aneurysms are a rare entity. Diagnosis of intracranial aneurysms in infancy may be difficult because of their infrequency and confusing clinical presentation. Findings with routine radiographic methods may be misleading and difficult to interpret. This case report entails a giant aneurysm arising from the right internal carotid artery (RICA) in an 8-month-old child.     

Iatrogenic venous air embolism during contrast enhanced computed tomography: a report of two cases

Venous air embolism (VAE) is a known complication of venous access procedures such as contrast-enhanced computed tomography (CECT). Although a massive VAE can be fatal, most iatrogenic VAE cases during CECT involve a few milliliters of air and are asymptomatic. We report two cases of massive and nonfatal VAE during CECT. Both cases involve the inadvertent injection of air instead of contrast by power injectors during the contrast phase. In both cases, the patients were stable and survived the event without permanent sequelae. We also discuss the pathophysiology, treatment, and prevention of VAE, especially during CECT.     

MDCT for suspected pulmonary embolism: multi-institutional survey of 16-MDCT data acquisition protocols

The purpose of this study was to determine the extent to which a consensus exists on multidetector row computed tomography (MDCT) protocol parameters for suspected pulmonary embolism (PE). In August of 2004, a questionnaire addressing a number of body MDCT protocols was mailed to 99 fellows of the Society of Computed Body Tomography, representing a total of 46 institutions. In May 2005, this was followed up with a second mailing. The survey requested details pertaining to protocols for the most advanced MDCT scanner in the department. The overall survey response rate of 37% (17/46) yielded 15 protocols for 16-MDCT imaging of suspected PE. This data was tabulated and revealed a consensus for the use of bolus tracking, rapid contrast infusion, caudo-cranial scanning, the narrowest detector row collimation, and thin (<2 mm) reconstruction sections. However, contrast infusion timing, contrast concentration, and implementation of radiation dose modulation were variable. This compilation of protocols reflects recently published studies advocating the use of narrow acquisition collimation and reconstruction sections for MDCT of suspected PE. Future studies are necessary to elucidate the optimal intravenous contrast infusion parameters and further assess the efficacy of reduced radiation dose protocols.     

Multidetector computed tomography of pediatric large airway diseases: state-of-the-art

Advances in multidetector computed tomography (MDCT) technology have given rise to improvements in the noninvasive and comprehensive assessment of the large airways in pediatric patients. Superb two-dimensional and three-dimensional reconstruction MDCT images have revolutionized the display of large airways and enhanced the ability to diagnose large airway diseases in children. The 320-MDCT scanner, which provides combined detailed anatomic and dynamic functional information assessment of the large airways, is promising for the assessment of dynamic large airway disease such as tracheobronchomalacia. This article discusses imaging techniques and clinical applications of MDCT for assessing large airway diseases in pediatric patients.     

Comparison of MDCT and MRI in the detection and sizing of acute and chronic myocardial infarcts

AIM: To assess the value of data set coregistration of gamma camera and computed tomography (CT) in the assessment of targeting of humanized monoclonal antibody 3S193 labeled with indium-111 ((111)In-hu3S193) to small cell lung cancer (SCLC). METHODS AND MATERIALS: Ten patients (6 male and 4 female; mean age+/-S.D., 60+/-4 years), from an overall population of 20 patients with SCLCs expressing Lewis Y antigen at immunohistochemical analysis, completed a four weekly injections of (111)In-hu3S193 and underwent gamma camera imaging. All had had, as part of their baseline evaluation, Fluorine18 fluoro-2-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). Two readers in consensus retrospectively coregistered the gamma camera images with the CT component of the FDG PET/CT by automatic or manual alignment. The resulting image sets were visually examined and SCLC lesions targeting at coregistered gamma camera and CT was correlated side-by-side with the (18)F-FDG uptake. RESULTS: A total number of 31 lesions from SCLC with a thoracic (n=13) or extrathoracic location (n=18) were all positive on FDG PET/CT. Coregistration of the gamma camera to the CT demonstrated targeting of antibody to all lesions >2 cm (n=20) and in a few lesions < or =2 cm (n=2), with no visualization of most lesions < or = 2 cm (n=9). No (111)In-hu3S193 uptake in normal tissues was observed. CONCLUSION: Coregistration of antibody gamma camera imaging to FDG PET/CT is feasible and allows valuable assessment of (111)In-hu3S193 antibody targeting to SCLC lesions >2cm, while lesions < or =2 cm reveal a limited targeting.