Multislice Computed Tomography Scan Research Articles

Maxillary symmetry, mandibular symmetry and condylar position in functional unilateral posterior cross bite patients

Objective: To investigate mandibular symmetry, maxillary symmetry and condylar position in patients with functional unilateral posterior crossbite (FUPXB) using Multi-slice computed tomography (MSCT). Materials and Methods: 15 patients (mean age 13 ± 3 years) with FUPXB underwent MSCT scans. Skeletal and dental measurements were taken to assess mandibular and maxillary symmetry. Medial and Lateral Joint spaces were compared between normal and crossbite sides in those patients. Results: There were no statistically significant differences between crossbite and normal sides regarding skeletal and dental mandibular and maxillary measurements and regarding condylar position. Conclusions: patients with FUPXB showed mandibular and maxillary symmetry. Those patients revealed symmetric condylar position between normal and crossbite sides.

Characterization of the interatrial septum by high-field cardiac MRI: a comparison with multi-slice computed tomography

BackgroundAssessment of the interatrial septum (IAS) has become an attractive area of interest for a variety of important interventional procedures. Newer imaging modalities like multi-slice computed tomography (MSCT) and cardiac MRI (CMR) can provide higher resolution and wider field of view than echocardiography. Moreover, high-field (3-Tesla) CMR can even enhance spatial and temporal resolution.The characteristics of the interatrial septum were retrospectively studied in 371 consecutive subjects (201 men, 31–73 years old) in whom MSCT was performed primarily for non-invasive evaluation of the coronary arteries. All subjects underwent both MSCT and MRI scans within 0–30 day’s interval. A 3D volume covering the whole heart was acquired across the heart with and without contrast enhancement. Also, patients underwent cardiac MSCT examinations using 64-row MSCT scanners.ResultsThe mean scan time of MSCT was 10.4 ± 2.8 s and 9.7 ± 2.9 min for CMR. The mean length of IAS by CMR and CT was 39.65 ± 4.6 mm and 39.28 ± 4.7 mm, respectively. The mean maximal thickness of IAS by CMR and CT was 3.1 ± 0.97 mm and 3.15 ± 0.95 mm, respectively. The mean thickness of fossa ovalis by CMR and CT was 1.04 ± 0.36 mm and 1.04 ± 0.44 mm, respectively. The mean length of fossa ovalis by CMR and CT was 12.8 ± 3.7 mm and 12.8 ± 3.5 mm, respectively. Finally, the mean angle of IAS by CMR and CT was identical (155 ± 9.2°). Measurements of various morphological features of IAS showed no statistically significant difference between CMR and CT, with an excellent correlation and close relationship regarding IAS length, maximal IAS thickness, fossa ovalis thickness, fossa ovalis length, and IAS angle (r = 0.98, 0.98, 0.95, 0.96, and 0.92, respectively).ConclusionWhole-heart 3D acquisition at 3-T MRI using a free-breathing technique provides a valuable non-invasive imaging tool for excellent assessment of the interatrial septum—as compared to MSCT—that may have significant clinical implication for diagnostic purposes and therapeutic interventional procedures, as it may facilitate planning, improve outcome, and shorten its duration.

EVALUATION OF DOUBLE LEVEL POSTERIOR LUMBAR INTER BODY FUSION USING POLYETHERETHERKETONE CAGES BY COMPUTED TOMOGRAPHY

PLIF is performed commonly nowadays due to the high prevalence of degenerative spinal conditions.Removing the disk material and cartilaginous end plates from the involved intervertebral disk space and filling up the void with a spacer maintaing disk height and to decompress the neural foraminain the anterior and middle spinal columns will increase the chance for bony fusion.Several types of cages are available as ex. polyetheretherketone (PEEK).CT provides a sensitiveThe aim of this study was to evaluate the fusion of double level PLIF using PEEK cages by computed tomographyFusion assessment:We evaluated the bone fusion at least one year post surgery. Multislice CT scans were done for all patients . Classification of interbody fusion success was evaluated according to criteria based on Brantigan, Steffee, and Fraser (BSF) criteria: BSF-1:Radiographic pseudoarthrosis (non-union) is indicated by: collapse of the construct , loss of disc height,vertebral slip, broken screws,displacement of the cage, significant resorption of the bone graft, lucency visible around the periphery of the graft or cage.b) BSF-2:Radiographic locked pseudoarthrosis (questionable fusion) is indicated by lucency visible in the middle of the cage with solid bone growing into the cage from each vertebral endplate.c) BSF-3:Radiographic fusion is indicated by bone bridges at least half of the fusion area with at least the density originally achieved at surgery.. assessment of interbody fusion.

Threshold Determination in Multislice CT-SCan using Improved Marching Cube Algorithm (IMCA) for 3D Image Reconstruction Process (3D-IRP)

Medical diagnostic information has been a change in clinical medicine development, including medical image and computer technology. The paper aims to determine the threshold for the 3D-IRP with a multislice Computerized Tomography Scan (CT-Scan). The 3D-IRP method is the IMCA technique. Skull and Sternum are the focus of the 3D medical image. It is in the multislice CT-Scan format of Digital Imaging and Communications in Medicine (DICOM). Surface volume and area, and visual shape are performance criteria of the 3D-IRP are matching with a software package (InVesalius ver. 3.1). The optimum threshold for the 3D bone representation of objects is 210. The difference in 3D image surface area and volume between the prototype's performance and the software package is smaller than 0.50%. Based on the three radiologists, the Skull and Sternum's visual shape is roughly 100% balanced.

Impact of Preprocedural Aortic Valve Calcification on Conduction Disturbances after Transfemoral Aortic Valve Replacement

Aim: The present study analyzes in depth the impact of different calcification patterns on disturbances of the conduction system in transcatheter aortic valve replacement (TAVR) patients. Methods and Results: A total of 169 preprocedural TAVR multislice computed tomography scans from consecutive transfemoral (TF) TAVRs performed between 2014 and 2017 using either Edwards SAPIEN or Medtronic Evolut R valves were retrospectively evaluated. The volume, distribution, and orientation of annular and valvular aortic valve calcification were measured and their impact on postoperative conduction disturbances was determined using linear and logistic regression analyses. The total volume of calcification and distribution at the aortic annulus or valve did not influence the conduction system. Oval calcification of the left aortic cusp was independently associated with an elevated risk for an increase in atrioventricular block degree (+0.6, p = 0.03). Moreover, orthogonal calcifications at the level of the aortic annulus were associated with an increased risk for QRS prolongation (+26 ms, p = 0.004) and an increased risk for permanent pacemaker implantation (OR 4.3, p = 0.03) after TF TAVR. This was more pronounced in patients undergoing TF TAVR using a balloon-expandable Edwards SAPIEN 3 valve (QRS +38.195 ms, p < 0.001; OR permanent pacemaker 15.48, p = 0.013). Conclusion: Orthogonal annular calcification confers an increased risk for conduction disturbances after TAVR. This is even more pronounced after implantation of balloon-expandable valves.

Bone ingrowth into open architecture PEEK interference screw after ACL reconstruction

PurposeOpen or fenestrated interference screw design that allow bone ingrowth is a concept for improved bone healing to softtissue graft and bone filling in bone tunnels after anterior cruciate ligament reconstruction (ACLR) The aim of the current study was to assess CT scanning evaluated bone ingrowth into an open architecture interference screws in the tibial tunnel of patients undergoing ACL with soft tissue grafts. It was hypothesized that open architecture interference screws would stimulate bone ingrowth into the screw cavities.MethodsTwelve patients requiring ACLR were included. They underwent arthroscopic ACLR with semitendinosus−/gracilis tendon graft and an open architecture polyetheretherketone (PEEK) interference screw. The patients were scanned with a multi-slice CT scanner two weeks, six and twelve months postoperatively. On CT reconstruction slices bone ingrowth into the screw was measured. Subjective and objective clinical outcome international knee documentation committee score and instrumented knee laxity determination were collected.ResultsAt six months no implants demonstrated more than 10% bone ingrowth. At twelve months 42% (5/12) implants had more than 10% bone ingrowth (p = 0.009). The average bone filling into the screws was 7.7%. There was no tunnel widening or cyst formation seen in relation to any of the implants. Subjective IKDC score improved significantly from 50.6 baseline to 80.1 at 24 month follow-up. Preoperative side-to-side knee laxity improved from 3.7 (2.1) to 1.4 (1.2) mm at twelve months. There were no serious adverse events in relation to the new open architecture thread PEEK interference screw during or after hamstring ACL reconstruction.ConclusionThe present study demonstrated that open architecture thread PEEK interference screw can stimulate bone ingrowth into the screws after soft tissue ACL reconstruction with at 12 months with an average bone filling into screws was 7.7%. Knee stability, functional, subjective and objective outcomes were similar to large volume ACL outcome studies.Trial registrationThe study was registered at ClinicalTrials # NCT02382341. 12-09-2014.Level of evidenceIV.

Radiation exposure of computed tomography imaging for the assessment of acute stroke

PurposeTo assess suspected acute stroke, the computed tomography (CT) protocol contains a non-contrast CT (NCCT), a CT angiography (CTA), and a CT perfusion (CTP). Due to assumably high radiation doses of the complete protocol, the aim of this study is to examine radiation exposure and to establish diagnostic reference levels (DRLs).MethodsIn this retrospective study, dose data of 921 patients with initial CT imaging for suspected acute stroke and dose monitoring with a DICOM header–based tracking and monitoring software were analyzed. Between June 2017 and January 2020, 1655 CT scans were included, which were performed on three different modern multi-slice CT scanners, including 921 NCCT, 465 CTA, and 269 CTP scans. Radiation exposure was reported for CT dose index (CTDIvol) and dose-length product (DLP). DRLs were set at the 75th percentile of dose distribution.ResultsDRLs were assessed for each step (CTDIvol/DLP): NCCT 33.9 mGy/527.8 mGy cm and CTA 13.7 mGy/478.3 mGy cm. Radiation exposure of CTP was invariable and depended on CT device and its protocol settings with CTDIvol 124.9–258.2 mGy and DLP 1852.6–3044.3 mGy cm.ConclusionPerforming complementary CT techniques such as CTA and CTP for the assessment of acute stroke increases total radiation exposure. Hence, the revised DRLs for the complete protocol are required, where our local DRLs may help as benchmarks.

Is routine colonoscopy necessary for patients who have an unequivocal computerised tomography diagnosis of acute diverticulitis?

To assess the incidence of underlying colorectal malignancy in patients admitted as an emergency with a CT diagnosis of acute diverticulitis and determine the need for routine follow up colonoscopy. A retrospective study was performed on all patients who had been admitted to our surgical unit with CT diagnosed diverticulitis from September 2016 to September 2018 (n = 125). 11 patients (8.8%) required emergency resection with no underlying malignancy found. 76 patients (61%) had a follow up colonoscopy after being discharged. 4 patients were found to have an underlying colorectal malignancy, one of them suspected on CT and another an incidentally detected caecal polyp cancer. Therefore 3/87(3.4%) had an unexpected cancer diagnosis and all those in the diseased segment were within complicated diverticulitis. Nowadays, multi-slice CT scanners are so good at giving an accurate assessment of colonic pathology. In our study, 96.6% of the patients with a CT diagnosis of acute diverticulitis had no underlying malignancy in the diseased segment with all the cancers within complicated diverticulitis. With such a low yield of underlying malignancy in uncomplicated diverticulitis, we question the need for routine follow up colonoscopy when there is no CT suspicion of malignancy in these patients.

Endoscopic Assessment of the Isthmus Tympanicum and Tensor Tympani Fold and their Relationship with Mastoid Pneumatization in Chronic Otitis Media.

To endoscopically evaluate the patency of the isthmus tympanicum and integrity of the tensor tympani fold as routes of ventilation of the attic and mastoid in chronic otitis media (COM) and to assess their effects on mastoid pneumatization. Sixty patients with COM were categorized into two groups: (1) Group A: 36 patients with tympanic membrane perforation (2) Group B: 24 patients with limited attic disease of whom 14 patients had attic retraction pockets and 10 with limited attic cholesteatoma. A multislice computed tomography scan of the temporal bone was performed for each patient to assess the degree of mastoid pneumatization. Notably, either myringoplasty or tympanomastoid surgery was performed in all patients. An endoscope was inserted into the middle ear for evaluation of the isthmus tympanicum and tensor fold area. The isthmus tympanicum was patent in most ears (83.3%) of group A, whereas it was blocked in most ears (83.3%) of group B. The tensor fold was complete in 77.8% of ears in group A and 83.3% of ears in group B. It was observed that 94.1% of ears with patent isthmus in both groups had normal mastoid pneumatization and 5.9% of ears had poorly pneumatized mastoid. By contrast, 7.7% of ears with blocked isthmus tympanicum had normal mastoid pneumatization and 92.3% had poor mastoid pneumatization. Normal mastoid pneumatization was observed in 50% of ears in both groups with complete tensor fold, and 83.3% of ears with an incomplete tensor fold. A significant correlation was observed between COM with limited attic disease and obstruction of the isthmus tympanicum. Obstruction of isthmus tympanicum was associated with poor mastoid pneumatization. Furthermore, an incomplete tensor fold was associated with well pneumatized mastoid.

SPECT/CT: Standing on the Shoulders of Giants, It Is Time to Reach for the Sky!

Twenty years ago, SPECT/CT became commercially available, combining the strengths of both techniques: the diagnostic sensitivity of SPECT and the anatomic detail of CT. Other benefits initially included attenuation correction of SPECT reconstructions, ultimately evolving to correction techniques that would enable absolute tracer uptake quantification. Recent developments in SPECT hardware include solid-state digital systems with higher sensitivity and resolution, using novel collimator designs based on tungsten. Similar advances in CT technology have been introduced in hybrid SPECT/CT systems, replacing low-end x-ray tubes with high-end multislice CT scanners equipped with iterative reconstruction, metal artifact reduction algorithms, and dual-energy capabilities. More recently, the design of whole-body SPECT/CT systems has taken another major leap with the introduction of a ring-shaped gantry equipped with multiple movable detectors surrounding the patient. These exciting developments have fueled efforts to develop novel SPECT radiopharmaceuticals, creating new chelators and prosthetic groups for radiolabeling. Innovative SPECT radionuclide pairs have now become available for radiolabeling with the potential for use as theranostic agents. The growth of precision medicine and the associated need for accurate radionuclide treatment dosimetry will likely drive the use of SPECT/CT in the near future. In addition, expanding clinical applications of SPECT/CT in other areas such as orthopedics offer exciting opportunities. Although it is true that the SPECT/CT ecosystem has seen several challenges during its development over the past 2 decades, it is now a feature-rich and mature tool ready for clinical prime time.

To evaluate accuracy of multislice CT scan as early predictor of severe pancreatitis

Background: In this study 200 patients with an aim to evaluate accuracy of Multislice CT Scan as early predictor of Severe Pancreatitis at Index Medical College, Indore, of the departments of General Surgery & General Medicine with a diagnosis of acute pancreatitis. Method: This is a prospective observational study to evaluate whether the C-reactive protein (CRP) levels and blood urea nitrogen predict the severity of pancreatitis by correlating these levels with CT severity index. Patients were enrolled in the study after obtaining informed patient consent. Result: Spearman's rho of bivariate analysis was done to see the correlation between the CECT on day 3rd with Marshall scoring system on 7th day of admission. Spearmans rho value was 0.772, which shows the strongest positive correlation. Kruskall-Wallis Test was applied to calculate the p value of test is 0.000, which was found statistically significant. Conclusion: To conclude, present study was again emphasize to significance of serial monitoring of BUN and CRP on day 1st 3rd 6th and Multi-slice CT scan as early prediction of severity of Pancreatitis. Although CECT alone is an excellent modality to predict the severity of Pancreatitis, but the levels of BUN & CRP acts as an adjunct to predict the severity more accurately.

Stature estimation of the Malaysian population based on sacrum CT scans

BackgroundThe evolution of virtual technology in estimating stature through multi-slice computed tomography scanning can be essential for mass disasters and forensic cases. Regression formulae were generated directly from other skeleton parts such as cranium, sternum, vertebrae, clavicle, scapula, sacrum, pelvis, hand and foot bones to estimate stature. Previous studies have shown that pelvic shape score is significantly associated and correlated with stature for both sexes. The sacrum as part of the pelvis is located between the two os coxae via a sacroiliac joint. As such, this study aims to correlate the morphological measurement of sacrum with stature based on sex and ancestry among the Malaysian population from a total of 373 sacral computed tomography (CT) images collected at the Kuala Lumpur Hospital. The three-dimensional sacrum bones were segmented from CT images using the Mimics Research 17.0 software. Inter-landmark distances were measured using Microsoft 3D Builder, and their respective indices were computed.ResultsThe auricular lengths are the most comparatively useful stature estimator at R > 0.5 among all the sacral morphometrics that were investigated on in this study. Results from this study should only be applied within the Malaysian population (Malay, Chinese and Indian).ConclusionThe results could enhance the existing database of stature estimation, especially when dealing with skeletal material from Malaysia and when long bones are unavailable for the identification of incomplete unknown human remains.

Optimisation of CT scan parameters to increase the accuracy of gross tumour volume identification in brain radiotherapy

AbstractAim:This study aimed to optimise computed tomography (CT) simulation scan parameters to increase the accuracy for gross tumour volume identification in brain radiotherapy. For this purpose, high-contrast scan protocols were assessed.Materials and methods:A CT accreditation phantom (ACR Gammex 464) was used to optimise brain CT scan parameters on a Toshiba Alexion 16-row multislice CT scanner. Dose, tube voltage, tube current–time and CT dose index (CTDI) were varied to create five image quality enhancement (IQE) protocols. They were assessed in terms of contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and noise level and compared with a standard clinical protocol. Finally, the ability of the selected protocols to identify low-contrast objects was examined based on a subjective method.Results:Among the five IQE protocols, the one with the highest tube current–time product (250 mA) and lowest tube voltage (100 kVp) showed higher CNR, while another with a tube current–time product of 150 mA and a tube voltage of 135 kVp had improved SNR and lower noise level compared to the standard protocol. In contouring low-contrast objects, the protocol with the highest milliampere and lowest peak kilovoltage exhibited the lowest error rate (1%) compared to the standard protocol (25%).Findings:CT image quality should be optimised using the high-dose parameters created in this study to provide better soft tissue contrast. This could lead to an accurate identification of gross tumour volume recognition in the planning of radiotherapy treatment.

Contrast reflux into the inferior vena cava on computer tomographic pulmonary angiography is a predictor of 24-hour and 30-day mortality in patients with acute pulmonary embolism.

Acute pulmonary embolism (PE) is a common disease with a high mortality. Computed tomographic pulmonary angiography (CTPA) represents the current gold standard for the evaluation of patients with suspected PE. To search possible CTPA predictors of 24-h and 30-day mortality in PE. Overall, 224 patients with PE (46.4% women, mean age 64.7 ± 16.7 years) were acquired. CTPA was performed on a multi-slice CT scanner. The following radiological parameters were estimated: thrombotic obstruction index; diameter of the pulmonary trunk (mm); short axis ratio of right ventricle/left ventricle; diameter of the azygos vein (mm); diameter of the superior and inferior vena cava (mm); and reflux of contrast medium into the inferior vena cava (IVC). Patients who died within the first 24 h after admission (n = 32, 14.3%) showed a reflux grade 3 into IVC more often than survivors (odds ratio [OR] 7.6, 95% confidence interval [CI] 3.3-17.7; P < 0.001). Other relevant CTPA parameters were diameter of IVC (OR 1.1, 95% CI 1.01-1.21; P = 0.034) and diameter of the pulmonary trunk (OR 0.91, 95% CI 0.82-1.01, P = 0.074), whereas the Mastora score showed nearly no influence (OR 1.01, 95% CI 0.99-1.02, P = 0.406). Furthermore, 61 (27.2%) patients died within the first 30 days after admission. These patients showed a reflux grade 3 into IVC more often than survivors (OR 3.4, 95% CI 1.7-7.0; P = 0.001). Other CTPA parameters, such as diameter of IVC (OR 1.04, 95% CI 0.97-1.12; P = 0.277) and diameter of the pulmonary trunk (OR 0.96, 95% CI 0.89-1.04; P = 0.291), seem to have no relevant influence, whereas Mastora score did (OR 0.99, 95% CI 0.976-0.999, P = 0.045). Subhepatic contrast reflux into IVC is a strong predictor of 24-h and 30-day mortality in patients with acute PE.

Improvement of image quality and diagnostic confidence using Smart MAR - a projection-based CT protocol in patients with orthopedic metallic implants in hip, spine, and shoulder.

In computed tomography (CT) scans, artifacts caused by metallic orthopedic implants still hamper the visualization of important, periprosthetic tissues. Smart MAR metal artifact reduction tool is a promising three-stage, projection-based, post-processing algorithm. To determine whether the Smart MAR tool improves subjective and objective image quality and diagnostic confidence in patients with orthopedic implants of the hip, spine, and shoulder. Seventy-two patients with orthopedic screws, hip/shoulder replacement, or spine spondylodesis were included. CT scans were performed on a single-source multislice CT scanner, raw data were post-processed using Smart MAR. Image quality was evaluated both quantitatively (ROI-based) and qualitatively (rater-based) and compared to iterative reconstructions (ASIR V). As comparative standard for artificial prosthetic breaks or loosening, follow-up examinations were used. Smart MAR reconstructions of the hip (n = 23), spine (n = 26), and shoulder (n = 23) showed a significantly reduced attenuation and noise of regions adjacent to metallic implants (P<0.002). Subjective image quality (P<0.005, shoulder P = 0.038/P = 0.046) and overall diagnostic confidence were higher in Smart MAR (all regions P<0.002). Signal-to-noise ratio (SNR; P = 0.72/P = 0.96) was not improved. Compared to standard ASIR V new, artificial metal extinctions (up to 50%) or periprosthetic hem lines (48%-73%) were introduced by Smart MAR. Smart MAR improved image quality of the hip, spine, and shoulder CT scans resulting in higher diagnostic confidence in evaluation of periprosthetic soft tissues. As shown for spine implants, it should be used with caution and as a complementary tool for evaluation of periprosthetic loosening or integrity of metal implant, as in many cases it introduced new artifacts.

Role of Computerized Tomography in Evaluation of Coronary Bypass Grafts—Special Reference to Women

AbstractComputerized tomography-coronary angiography (CT-CAG) is gaining popularity as an alternative to conventional CAG to evaluate grafts in a post-coronary artery bypass graft (post-CABG) patient, since it is a noninvasive procedure and is less influenced by cardiac motion. The primary challenge is to image a rapidly beating heart. With introduction of 64-slice scanner, the coronary imaging became a possibility with acceptable accuracy. In recent years, with the development of 128,256 and 320 multislice CT scanners, further enhancement in the temporal and spatial resolution is achieved due to lesser influence of the respiratory and cardiac motion, enhancing the accuracy of the lesion assessment in the grafts and the native vessels. Achieving low heart rate and artifact-free image acquisition, proper reconstruction, and image interpretation are challenges to the radiologists and the technicians involved in coronary imaging. Women pose special subset because of smaller sized coronary vessels, interference due to breast shadows, low-referrals, and gender-specific reluctance to accept the procedure itself. Cardiologists and radiologists caring for these patients must be familiar with the pros and cons of CT-CAG and gender-specific challenges.

Survey research on dynamic CTA data analysis for peripheral artery occlusive disease

The purpose of this study is to review the research which was mainly about the evaluation the vascular stenosis or muscle ischemia to assist in the diagnosis of peripheral arterial occlusive disease using dynamic CTA data. With the recent rapid evolution of multislice computed tomography scanners, runoff CTA of the peripheral artery has become a widely used diagnostic option in patients with PAOD. Furthermore the dynamic CTA of the lower extremity provides improved arterial contrast enhancement and a higher diagnostic confidence for assessment of stenosis and occlusion than runoff CTA. The method, the data characteristic and the conclusion of all the qualitative and quantitative research were covered in this study. Finally, the future research direction of the dynamic CTA analysis to assist diagnosis was given.

Tissue Contrast Differentiation between Head and Neck Squamous Cell Carcinoma Tumors and Adjacent Tissues in Early and Late Phases by Multi-Slice CT Scan

Background: Malignancies of head and neck are common cancers responsible for 6 percent of all malignancies. Use of multi-slice CT scan has led to shorter time of scan with optimal capacity in constant time. This study aimed to evaluate the tissue contrast differentiation between head and neck Squamous Cell Carcinoma tumors and adjacent muscle tissue in early and late phases by multi-slice CT scan. Methods and Materials: In this cross-sectional study, 76 patients with head and neck Squamous Cell Carcinoma referred to us in imaging center of Tehran Amir A'lam hospital in 2014-5015. Multi-slice CT scan were conducted at early time (20 seconds) and 180 and 300 seconds after contrast media injection. Then, Hounsfield score of affected tissue and nearest muscle was measured. Δ density was defined as the contrast between tumor density and nearest muscle density. Results: The mean of tumor density at early phase, late phase (180s) and (300s) was 75/76 ± 21/08, 75/26 ± 12/96 and 74/14 ± 12/57, respectively (P>0.05). Conversely, the muscle density significantly was lower in early phase compare to late phase (65/31 ± 11/65 vs. 69/06 ± 12/23 and 69/82 ± 10/69, P<0.001). Our results also showed that Δ density was decreased in late phases, however, this reduction was not statistically significant (P=0.08). Conclusion: Results indicated that multi-slice CT scan may have good tissue contrast differentiation ability between head and neck Squamous Cell Carcinoma tumors and adjacent muscle tissues in early phases after contrast media injection.

Investigating the agreement between the findings of multi-slice CT scan and surgical findings in the diagnosis and detection of metastasis of malignant ovarian tumors to the peritoneum and intra-abdominal organs

The present study was conducted to determine the agreement between the findings of multi-slice CT scan and surgical findings in the diagnosis and detection of metastases of malignant ovarian tumors to the peritoneum and intra-abdominal organs. In this cross-sectional study, 115 women with ovarian cancer who were hospitalized and underwent surgery in Al-Zahra Hospital during 1396 and 1397, underwent multi-slice CT scan of the abdomen and pelvis before the operation, and the presence of metastases in these areas was investigated; then the comparison of these results with the findings of the operation indicated the amount of agreement between the two methods, which was determined by the Kappa agreement test. According to the finding of the surgery, 96 patients (83.5%) and according to the findings of multi-slice CT scan, 94 patients (81.7%), had metastasis in adjacent tissues. Five patients (4.3%) had metastases in the surgical findings, but the result of CT scan was a negative. Also in 3 patients (2.6%), the presence of metastasis was negative in the surgical findings but the result of CT scan was positive. According to the Kappa agreement test, a significant agreement with the amount of 0.76 was observed between the findings of the surgery and the CT scan results. The results of this study showed that there is a favorable agreement between the findings of surgery and multi-slice CT scan in the diagnosis of metastasis of malignant ovarian tumors to abdominal and pelvic areas, However, due to the limitations of multi-slice CT scan in the diagnosis of metastases of malignant ovarian tumor to the abdomen and pelvis, including being dependent on the size and location of the tumor, the use of this diagnostic method may be helpful in cases where surgery is not possible and may be useful in determining surgical indication.

Multislice computed tomography evaluation of the expansion achieved by the nonextraction treatment of orthodontic cases using Damon system

Objectives The purpose of this study is to evaluate the dental, alveolar changes and behavior of teeth movement during expansion achieved by the nonextraction treatment approach of crowding cases using the Damon system. Materials and methods High-resolution multislice computed tomography (MSCT) imaging was performed pretreatment (T1) and posttreatment (T2) on a sample composed of twenty patients aged 17.8 ± 3.7 years in average selected based on a pretreatment class I skeletal and molar relationships, and moderate crowding range between 4.0 and 9.0 mm for the maxilla and 2.0 and 6.0 mm for the mandible. On the Digital Imaging and Communications (files obtained from MSCT scans, dental and alveolar measurements were recorded including interocclusal, interapical widths, angulations of the maxillary and mandibular teeth and four bilateral bone thickness distances at the furcation level. Results The evaluation of the study was performed by detecting the dental and alveolar changes between pretreatment and posttreatment MSCT scans. Paired t test was used for statistical analysis. The interocclusal to interapical ratio indicated that, the roots moved by the same distance as the crowns except the canines roots moved 15 times as the crowns. While in the mandible, the roots of the premolars and molars moved less than the crowns but in the canines the opposite was happened. There was a significant increase of the axis angles of the maxillary canines and a significant decrease of the axis angles of the mandibular second premolars and first molars. This expansion resulted in a significant decrease of the buccal bone thickness and alveolar width and a significant increase of the palatal and lingual bone thickness. Conclusion The results of this study revealed that the expansion produced a small amount of uprighting in the maxillary teeth and a more significant degree in the mandibular teeth except the mandibular first premolars, were tipped buccally.