Multidetector Computed Tomography Scans Research Articles

Multi-detector computed tomography (MDCT) evaluation of synchronous renal cell carcinoma and other solid malignancies

BackgroundMultiple primary malignant neoplasms (MPMNs) became more prevalent as the population aged and medical technology progressed. The purpose of this research was to review the findings of multidetector computed tomography (MDCT) in synchronous renal cell carcinoma and other solid tumors.Results31 individuals with synchronous renal cell carcinoma and additional solid cancers were included in this retrospective analysis. CT scanning was carried out using 64 MDCT scanners. All sixty-two malignancies were undergoing pathological assessment. Out of 685 patients with renal cell carcinoma, 31 individuals were identified with another primary solid cancer that occurred concurrently. All of our instances were pathologically verified. In all 31 individuals, clear renal cell carcinoma was found. The most frequent extra-renal malignancies were hepatocellular carcinoma (10/31), followed by breast carcinoma (4/31), non-Hodgkin lymphoma (4/31), bronchogenic carcinoma (3/31), colonic carcinoma (3/31), prostatic carcinoma (2/31), urinary bladder carcinoma (1/31), periampullary carcinoma (1/31), mucoepidermoid carcinoma (1/31) and skin squamous cell carcinoma (1/31) as well as malignant hemangioendothelioma (1/31).ConclusionMDCT scanning was an accurate imaging method for diagnosing synchronous renal cell carcinoma and other solid tumors. Even in the face of numerous cancers, the goal of therapy in cancer patients must always be curative. During the pretreatment examination, the potential of synchronous double malignancies with renal cell carcinoma should be explored.

Low-dose multi-detector computed tomography for periradicular infiltrations at the cervical and lumbar spine

Periradicular infiltrations are frequently performed in daily neuroradiological routine and are often guided by multi-detector computed tomography (MDCT), thus leading to radiation exposure. The purpose of this study was to evaluate MDCT with low dose (LD) and model-based iterative reconstruction for image-guided periradicular infiltrations at the cervical and lumbosacral spine. We retrospectively analyzed 204 MDCT scans acquired for the purpose of cervical or lumbosacral periradicular interventions, which were either derived from scanning with standard dose (SD; 40 mA and 120 kVp) or LD (20–30 mA and 120 kVp) using a 128-slice MDCT scanner. The SD cases were matched to the LD cases considering sex, age, level of infiltration, presence of spinal instrumentation, and body diameter. All images were reconstructed using model-based iterative image reconstruction and were evaluated by two readers (R1 and R2) using 5- or 3-point Likert scales (score of 1 reflects the best value per category). Furthermore, noise in imaging data was quantitatively measured by the standard deviation (StDev) of muscle tissue. The dose length product (DLP) was statistically significantly lower for LD scans (6.75 ± 6.43 mGy*cm vs. 10.16 ± 7.70 mGy*cm; p < 0.01; reduction of 33.5%). Image noise was comparable between LD and SD scans (13.13 ± 3.66 HU vs. 13.37 ± 4.08 HU; p = 0.85). Overall image quality was scored as good to very good with only minimal artifacts according to both readers, and determination of the nerve root was possible in almost all patients (LD vs. SD: p > 0.05 for all items). This resulted in high confidence for intervention planning as well as periprocedural intervention guidance for both SD and LD scans. The inter-reader agreement was at least substantial (weighted Cohen’s κ ≥ 0.62), except for confidence in intervention planning for LD scans (κ = 0.49). In conclusion, considerable dose reduction for planning and performing periradicular infiltrations with MDCT using model-based iterative image reconstruction is feasible and can be performed without clinically relevant drawbacks regarding image quality or confidence for planning.

Submillisievert CT chest for COVID-19 patients in a rural hospital with limited resources

BackgroundThis is a secondary analysis of prospectively acquired data approved by the hospital institutional board committee. We performed a retrospective chart review of 463 patients who underwent a CT Chest for suspected COVID-19 infection between April 1st, 2020, and March 31st, 2021. Patients were grouped based on the CT chest obtained protocol: ultra-low dose or full dose. The likelihood of suspicion of COVID-19 infection was classified on a Likert scale based on the probability of pulmonary involvement. For each group, the sensitivity and specificity of CT were compared to nasopharyngeal swab as standard of reference. The median dose length product and duration of apnea were compared between both groups using two-tailed Mann–Whitney U test. The aim of this study is to share our experience of reducing radiation dose in COVID-19 patients by using an ultra-low dose CT chest protocol on a 16 row multidetector CT scan in a hospital with limited resources.ResultsTwo hundred sixty-nine patients underwent a full dose CT and 194 patients an ultra-low dose CT. In the former group, the median dose length product was 341.11 mGy*cm [Interquartile range (IQR), 239.1–443.2] and the median duration of apnea was 13.29 s [IQR, 10.85–15.73]. In the latter group, the median dose length product was 30.8 mGy*cm [IQR, 28.9–32.7] and median duration of apnea was 8.27 s [IQR, 7.69–8.85]. The sensitivity of the ultra-low dose CT was 91.2% and that of the full dose was 94%.ConclusionA 90% reduction in estimated dose and 38% reduction in apnea duration could be achieved using an ultra-low dose CT chest protocol on a 16-row MDCT without significant loss in the sensitivity of CT to detect COVID-related parenchymal involvement.

Small Renal Masses without Gross Fat: What Is the Role of Contrast-Enhanced MDCT?

Increased detection of small renal masses (SRMs) has encouraged research for non-invasive diagnostic tools capable of adequately differentiating malignant vs. benign SRMs and the type of the tumour. Multi-detector computed tomography (MDCT) has been suggested as an alternative to intervention, therefore, it is important to determine both the capabilities and limitations of MDCT for SRM evaluation. In our study, two abdominal radiologists retrospectively blindly assessed MDCT scan images of 98 patients with incidentally detected lipid-poor SRMs that did not present as definitely aggressive lesions on CT. Radiological conclusions were compared to histopathological findings of materials obtained during surgery that were assumed as the gold standard. The probability (odds ratio (OR)) in regression analyses, sensitivity (SE), and specificity (SP) of predetermined SRM characteristics were calculated. Correct differentiation between malignant vs. benign SRMs was detected in 70.4% of cases, with more accurate identification of malignant (73%) in comparison to benign (65.7%) lesions. The radiological conclusions of SRM type matched histopathological findings in 56.1%. Central scarring (OR 10.6, p = 0.001), diameter of lesion (OR 2.4, p = 0.003), and homogeneous accumulation of contrast medium (OR 3.4, p = 0.03) significantly influenced the accuracy of malignant diagnosis. SE and SP of these parameters varied from 20.6% to 91.3% and 22.9% to 74.3%, respectively. In conclusion, MDCT is able to correctly differentiate malignant versus uncharacteristic benign SRMs in more than 2/3 of cases. However, frequency of the correct histopathological SRM type MDCT identification remains low.

Evaluating the performance of unenhanced computed tomography in the diagnosis of pulmonary embolism

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary embolism (PE) is the third most common cardiovascular pathology after coronary artery disease and stroke with an incidence rate of 1 per 1000 individuals. Computed tomography pulmonary angiography (CTPA) as the gold standard examination in the detection of PE is contraindicated or unavailable in certain cases. Purpose The current study aimed to assess the accuracy of unenhanced CT in the diagnosis of PE. Methods A total of 195 consecutive participants with clinical suspicion for PE were enrolled in this prospective cohort study between October 2020 and March 2021. All patients were examined with a 16 slice multidetector (MD) CT scanner before performing the CTPA. Scans were independently reviewed by two expert radiologists who were blinded to patients’ clinical and laboratory history for imaging variables including presence and location of PE, hyper/hypodense intraluminal signs, pulmonary trunk enlargement, peripheral wedge-shaped opacity, and pleural effusion. First unenhanced CT scan and then CTPA were independently reviewed on a picture archiving and communications system workstation. Results There were 82 (42.1%) men and 113 (57.9%) women with the mean age ± standard deviation of 56 ±0.24 years. Based on CTPA results, 47 (24.1%) of 195 patients had PE of which 28 (59.5%) patients had central PE and 19 (40.5%) patients had peripheral PE. However, only 20 cases (42.5%) were detected with PE on MDCT scans consisting of 17 cases with (85%) central emboli and 3 cases with (15%) peripheral emboli. Given intraluminal clot density, 12 (60%) patients had hyperdense signs, 3 (15%) patients had hypodense signs, and 5 (25%) patients had mixed hyper-hypodense signs. There was a significant difference between central and peripheral embolies detected by MDCT. Intraluminal sign had the highest specificity and sensitivity (98.6%, 42.5%, AUC:0.734) followed by pulmonary trunk enlargement (84.4%, 36.1%, AUC: 0.603), peripheral wedge-shaped opacity (72.9%, 34%, AUC: 0.535), and pleural effusion (58.7%, 40.4%, AUC: 0.496). Our results did not show a remarkable difference in secondary findings from the MDCT scan including pulmonary trunk enlargement, peripheral wedge-shaped opacity, and pleural effusion concerning the presence of PE. Pleural effusion as the most common secondary finding in patients with PE was found in 31 (68.8%) of them. Conclusion Unenhanced MDCT has an acceptable performance to detect PE particularly central clots and should be considered as an alternative modality when CTPA is not available or indicated. Furthermore, the intraluminal sign is the main indicator of PE in MDCT images with the highest specificity and sensitivity. We recommend radiologists and other clinicians to be aware of intraluminal signs in case of unexpected PE.

Gender Differences in Anatomic Variations of the Sternum Assessed by Multidetector CT Scan

Several anatomic variants can be recognized during imaging of the chest, some can be confused with pathology or have adverse consequences when attempting certain surgical procedures through the sternum. Aim: To assess sternal anatomic variations in adults and to evaluate gender differences in the frequency of these variants. Methods: Patient referred for chest CT scan were enrolled in the study. Analysis of the images was performed after post processing. Selected anatomic variations of the sternum were recorded. Analysis of the gender differences in the frequency of these variants was done. Results: The study included 817 patients with mean age of 48.5 ±16.32. Men represented 53.7% of the study population and women 46.3%. Most variants were detected in the xiphoid and the most frequent of these were xiphoid foramina. Total ossification of the xiphoid was seen in ventrally deviated xiphoid and xiphoid foramina were significantly higher in men than in women. Conclusion: The xiphoid process is the most likely segment of the sternum to have variations. There was no significant gender difference in the frequency of most sternal variants except xiphoid ossification, xiphoid foramina and elongated-ventrally deviated xiphoid.

Effect of Body Mass Index in Coronary CT Angiography Performed on a 256-Slice Multi-Detector CT Scanner.

We aimed to investigate the effect of a patient’s body mass index (BMI) on radiation dose and image quality in prospectively ECG-triggered coronary CT angiography (CCTA) performed on a 256-slice multi-detector CT scanner. In total, 87 consecutive patients receiving CCTA examinations acquired with tube current modulation (TCM) and iterative reconstruction (IR) were enrolled in this study. The dose report recorded from the CT scanner console was used to derive the effective dose for patients. Subjective image quality scoring and objective noise measurements were conducted to quantify the impact of BMI on the image quality of CCTA. Because of the TCM technique, we expected tube current and radiation dose to increase as BMI increased. However, using TCM did not always guarantee sufficient radiation exposure to achieve consistent image quality for overweight or obese patients since the maximum X-ray tube output in milliamperes and kilovoltage peak was reached. The impact of photon starvation noise on image quality was not significant until BMI ≥ 27 kg/m2; this result could be due to IR’s noise reduction capability. Our results also suggest that using TCM with a noise index of 25 HU can reduce radiation dose without compromising image quality compared to images obtained based on the manufacturer’s default settings.

A Contrast-Enhanced MDCT Study on the Morphology of Renal Vessels, Their Variations and Clinical Implications

Introduction: The kidneys--the main organs of the excretory system, are supplied by a paired renal artery, originating from the Abdominal Aorta at the level of a disc between L1 and L2 and drained by a paired renal vein exiting from the hilum of the kidney to the Inferior vena cava. Aim: To evaluate the morphology of renal vessels, their variations &amp; clinical implications during renal surgeries in the subjects of the North India population by contrast-enhanced MDCT. Materials and Method: The present study was conceptualized &amp; carried out in the Department of Anatomy, in collaboration with the Department of Radiodiagnosis, Santosh Medical College &amp; Hospital, Ghaziabad and from Dr. O.P Gupta Imaging Centre, Meerut. This study was performed on the 108 patients who were referred for abdominal CECT examination with suspected abdominal pathologies. Contrast-enhanced MDCT scan images of the Abdomen were reviewed for normal anatomy of renal vessels and their variants. Result: Out of 108 patients, anatomical variations of the renal vessel were found in 72 (66.66%) patients. Variations of the renal artery were found in 56 patients (51.85%). Out of these 56 patients, 47 had supplementary renal artery, 17 had early branching of the renal artery and 8 patients had both supplementary and early branching of the renal artery. Supplementary renal arteries were seen in 15 patients on the right side, 16 patients on the left side &amp; 16 patients bilaterally. Earlier branching of the renal artery was found in 9 patients on the right side, 10 patients on the left side and in 2 patients bilaterally. Variations of the renal vein were more commonly found on the right side, late renal vein confluence was seen in 28 (25.92%) patients and supplementary renal veins in 9 (8.3%) patients. On the left side, 2 (1.85%) patients had late renal vein confluence and 2 (1.85%) patients had retroaortic vein. Conclusion: Variations of the renal artery are found frequently. Morphological evaluation of renal vessels is useful for planning and performing the endovascular, laparoscopic and urological procedure. KEY WORDS: Renal artery (RA), Renal vein (RV), Supplementary Renal artery (SRA), Early branching (EB), Supplementary renal vein (SRV), Contrast-enhanced Multidetector Computerized Tomography (MDCT).

Multi-detector computed tomography evaluation of synchronous hepatocellular carcinoma and other solid malignancies.

To review the findings of multi-detector computed tomography (MDCT) in synchronous hepatocellular carcinoma (HCC) and other solid malignancies. A total of 74 cases were included in this retrospective analysis, all of them confirmed with a diagnosis of synchronous HCC and other solid malignancies. They were 41 women and 33 men (mean age, 63.36 years). The whole body and triphasic abdominal CT scanning utilized 128 MDCT scanners in all 74 patients. The pathological diagnoses of all 148 malignancies were confirmed in all 74 cases. Out of 3480 patients with HCC, 74 patients (2.1%) were diagnosed with another synchronous primary solid malignancy. The pathology of all 148 cancers was verified, and each one was correctly characterized, assessed, and staged. Hepatocellular carcinoma was detected in all 74 patients. The most frequent extra-hepatic primary malignant sites were breast (18/74, 24.3%), followed by kidney (15/74, 20.3%), lymphoma (9/74, 12.2%), uterus (7/74, 9.5%), ovary (5/74, 6.8%), colon (5/74, 6.8%), prostate (5/74, 6.8%), urinary bladder (3/74, 4.1%), thyroid (2/74, 2.7%), gall bladder (1/74, 1.4%), stomach (1/74, 1.4%), pancreas (1/74, 1.4%), esophagus (1/74, 1.4%) and lung (1/74, 1.4%). The possibility of synchronous double malignancies with HCC should always be considered during pretreatment evaluation. Using an MDCT scanner, researchers were able to assess this occurrence accurately. An increased number of such findings may lead to an improved therapeutic method for these patients.

Can epicardial and pericardial adipose tissue volume predict the presence and severity of coronary artery disease?

PurposeExcessive accumulation of free fatty acids in the coronary arteries can lead to coronary artery disease (CAD). Quantification of epicardial adipose tissue (EAT) and pericardial adipose tissue (PAT) is beneficial to understand its relationship with CAD, hypertension (HT), and diabetes.Material and methodsThis retrospective study included 54 patients who underwent CT coronary angiogram using a multidetector row CT scanner. The EAT and PAT volumes from cardiac images were quantified using Image J software. The severity of CAD was graded using the CAD-RADS score.ResultsTwenty-nine patients had no CAD, 21 patients had significant CAD, and 4 patients had insignificant CAD. Out of 21 patients with significant CAD, 14 had involvement of multiple coronary arteries. The EAT and PAT volumes were higher in patients with HT, DM, CAD-present group and significant-CAD-present group, but this was not statistically significant except the PAT volume with respect to diabetes. Significant correlation was found between EAT volume and calcium score (p = 0.035) and between EAT volume and total cholesterol level (p = 0.017). Significant differences in the EAT volumes were found in different CAD-RADS categories in the right coronary artery (RCA). From the threshold values, it was observed that CAD can develop in LAD even at lower of EAT and PAT volumes.ConclusionsQuantification of EAT and PAT volumes is beneficial in understanding its relationship with the presence and severity of coronary artery disease and its risk factors.

Evaluation of Diameter of Main Hilar Renal Artery to Predict the Presence of Supplementary Renal Artery by Contrast-enhanced MDCT: A Retrospective Study from in Northern India

Introduction: Accessory renal arteries are non anastomotic end arteries that correspond to a single renal artery’s segmental branch. It is the most common anatomic variation of renal artery, with an incidence ranging from 8.7% to 75.7%. Aim: To determine the normal reference range of diameter of the main hilar renal artery in presence or absence of supplementary renal arteries and using contrast-enhanced Multidetector Computerized Tomography (MDCT) in North Indian population. Materials and Methods: This retrospective study was conducted in the Department of Anatomy in collaboration with the Department of Radiodiagnosis at Santosh Medical College and Hospital, Ghaziabad and Dr. O.P Gupta Imaging Centre, Meerut, Uttar Pradesh, India, from April 2019 to October 2021. Data analysis was done from November 2021 to December 2021. Contrast-enhanced MDCT scan images were reviewed for measurement of the diameter of main hilar and supplementary renal artery. A total of 108 patients were recruited through consecutive sampling. The diameter of the main hilar and supplementary renal artery on each side was measured at the site of origin from the abdominal aorta with the help of an electronic calliper in axial view of MDCT images. The mean differences among the groups with and without supplementary renal artery were evaluated using the student’s t-test. Results: The mean diameter of the main hilar renal artery in the absence of the supplementary renal arteries on the right and left side were 5.99±1.13 mm and 6.07±1.25 mm respectively.The mean diameter of the main hilar renal artery with supplementary renal arteries on the right side was 5.11±1.096 mm and on the left was 5.18±1.08. The mean diameter of the main hilar renal artery was smaller in kidneys with a supplementary renal artery than in those without a supplementary renal artery, statistically significant difference was evaluated (p-value&lt;0.001 on the right and left side). Conclusion: The diameter of the main hilar renal artery can indicate whether supplemental renal arteries exist or not.

CT Appearances in Treated Abdominal Tuberculosis: A Radiologist's Dilemma

Abstract Objective To study the CT appearances of the abdomen after completion of antitubercular therapy (ATT) in adult patients. Methods Multidetector CT scan abdomen was done in 20 adults within 1 month of completing ATT. CT appearances were compared with pretreatment scans which were available in 7 cases. Results We found that residual ileocecal wall thickening and enhancement was significant (p &lt; 0.05) after treatment in cases of ileocecal tuberculosis (TB). Mild decrease in wall thickness and diameter of the involved dilated small bowel loops was seen. Numerous large, matted nodes with necrosis persisted in the mesentery and retroperitoneum in treated TB, but reduction in the size of nodes was appreciated. Conclusion Our results help to fill the vacuum in the database of CT appearances in treated abdominal TB. Persistence of bowel changes and lymph nodes should not be mistaken for recurrence of TB or residual disease.

The impact of the field of view (FOV) on image quality in MDCT angiography of the lower extremities

ObjectivesTo evaluate the impact of the reconstructed field-of-view (FOV) on image quality in computed-tomography angiography (CTA) of the lower extremities.MethodsA total of 100 CTA examinations of the lower extremities were acquired on a 2 × 192-slice multidetector CT (MDCT) scanner. Three different datasets were reconstructed covering both legs (standard FOV size) as well as each leg separately (reduced FOV size). The subjective image quality was evaluated for the different vessel segments (femoral, popliteal, crural, pedal) by three readers using a semi-quantitative Likert scale. Additionally, objective image quality was assessed using an automated image quality metric on a per-slice basis.ResultsThe subjective assessment of the image quality showed an almost perfect interrater agreement. The image quality of the small FOV datasets was rated significantly higher as compared to the large datasets for all patients and vessel segments (p < 0.05) with a tendency towards a higher effect in smaller vessels. The difference of the mean scores between the group with the large FOV and small FOV was 0.68 for the femoral level, 0.83 for the popliteal level, 1.12 for the crural level, and 1.08 for the pedal level. The objective image quality metric also demonstrated a significant improvement of image quality in the small FOV datasets.ConclusionsSide-separated reconstruction of each leg in CTA of the lower extremities using a small reconstruction FOV significantly improves image quality as compared to a standard reconstruction with a large FOV covering both legs.Key Points• In CT angiography of the lower legs, the side-separated reconstruction of each leg using a small field-of-views improves image quality as compared to a standard reconstruction covering both legs.• The side-separated reconstruction can be readily implemented at every commercially available CT scanner.• There is no need for additional hardware or software and no additional burden to the patient.

Estimation of sex based on metrics of the sternum in a contemporary Jordanian population: A computed tomographic study.

There is a paucity of osteometric standards for sex estimation from unknown skeletal remains in Jordan and the sexual dimorphism of the sternum has not yet been investigated. The aim of this study was to evaluate the sexual dimorphism in sternal measurements using 3D multidetector computed tomography (MDCT), and to assess their reliability for sex estimation in a Jordanian population. A total of 600 MDCT scans (300 males and 300 females) were used and a total of 8 sternal measurements were studied (manubrium length, sternal body length, combined length of manubrium and body, corpus sterni width at 1st and 3rd sternebrae, sternal index and area). Sexual dimorphism was evaluated by means of discriminant function analyses. Significant sexual dimorphism was found mainly in middle-aged and older adults. Including all subjects, multivariate, and stepwise functions gave an overall accuracy of 83.0% and 84.0%, respectively. Additionally, multivariate and stepwise analyses were conducted separately for each age group. The accuracy of sex estimation in multivariate analysis (all variables) varied from 63.2% in the young, and 83.7% in the middle adults to 84.9% for older adults. In stepwise analysis, the highest accuracy rates were provided by only sternal area in young adults (81.6%), and sternal area combined with sternal body length in middle-aged and older adults (84.2% and 85.3%, respectively). The best sex discriminator using univariate analysis (single variable) was sternal area followed by sternal body length (84.0% and 80.8% respectively). Notably, univariate analyses for most variables gave relatively higher classification accuracies in females but were poor at predicting males in the sample (sex bias ranged between −6.4% and −20%). Our data suggest that dimorphism in the human sternum increases with advancing age and separate discriminant functions are needed for each age group in Jordanians. In addition, multivariate and stepwise analyses using sternum gave higher classification accuracies with comparatively lower sex biases compared to univariate analyses.

Reduction of metal artifacts from knee tumor prostheses on CT images: value of the single energy metal artifact reduction (SEMAR) algorithm

BackgroundTo evaluate the effect of the single energy metal artifact reduction (SEMAR) algorithm with a multidetector CT (MDCT) for knee tumor prostheses.MethodsFirst, a phantom of knee tumor prosthesis underwent a MDCT scan. The raw data was reconstructed by iterative reconstruction (IR) alone and IR plus SEMAR. The mean value of the CT number and the image noise were measured around the prosthesis at the stem level and articular level. Second, 95 consecutive patients with knee tumor prostheses underwent MDCT scans. The raw data were also reconstructed by the two methods. Periprosthetic structures were selected at the similar two levels. Four radiologists visually graded the image quality on a scale from 0 to 5. Additionally, the readers also assessed the presence of prosthetic complication and tumor recurrence on a same scale.ResultsIn the phantom, when the SEMAR was used, the CT numbers were closer to normal value and the noise of images using soft and sharper kernel were respectively reduced by up to 77.1% and 43.4% at the stem level, and by up to 82.2% and 64.5% at the articular level. The subjective scores increased 1 ~ 3 points and 1 ~ 4 points at the two levels, respectively. Prosthetic complications and tumor recurrence were diagnosed in 66 patients. And the SEMAR increased the diagnostic confidence of prosthetic complications and tumor recurrence (4 ~ 5 vs. 1 ~ 1.5).ConclusionsThe SEMAR algorithm can significantly reduce the metal artifacts and increase diagnostic confidence of prosthetic complications and tumor recurrence in patients with knee tumor prostheses.

Abstract 10638: The Time to Reach the Minimum Freezing Temperature During Cryoablation is a Predictor of First-Pass Conductional Block of Cavotricuspid Isthmus

Background: Ablation using cryothermal energy has several potential advantages over radiofrequency (RF) ablation including a greater catheter stability due to adherence to the myocardial tissue during applications, reduced risk of thrombus formation, less pain, and etc. Several studies have reported the effects of cryoablation for the treatment of the cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) with similar efficacy and safety rates as reported for RF ablation. However, the details of freezing profile during CTI cryoablation still remain unknown. Methods: This study included 40 consecutive patients (32 men; 65±10 years) who underwent CTI cryoablation for common AFL. Patients were divided into 2 groups: one pass group who achieved first-pass conductional block of the CTI (n=30) and non-one pass group who did not (n=10). CTI ablation was performed with 2.5-min freezing cycle and 8-mm tip cryocatheters. A multidetector computed tomography scan with contrast injection which was performed before ablation in all the patients. We examined temperature changes at the catheter tip during first pass in CTI cryoablation and anatomical features of CTI in three regions: anterior, middle, and posterior. Results: There was no significant difference in the minimum freezing temperature between the one pass group and the non-one pass group (-82.6±1.6 vs. -83.2±1.2°C, P=0.245) in all the three regions. However, only in the anterior CTI, the time to reach the minimum freezing temperature was significantly shorter in the one pass group than in the non-one pass group (31.4±5.9 vs. 38.7±8.6 sec, P=0.012). The thickness of the anterior CTI was significantly thinner in the one pass group than in the non-one pass group (4.1±1.2 vs. 5.5±1.3 mm, P=0.021). On the other hand, there was no significant difference in the thickness of the middle and posterior CTI between the two groups. The time to reach the minimum freezing temperature showed a significant positive correlation with the thickness of the CTI (R=0.415, P&lt;0.001). Conclusions: The time to reach the minimum freezing temperature in the anterior CTI may predict a first-pass conductional block of CTI cryoablation. The thickness of the anterior CTI may relate to this mechanism.

Assessing predictors of rheumatoid arthritis-associated interstitial lung disease using quantitative lung densitometry.

To assess predictors of subclinical RA-associated interstitial lung disease (RA-ILD) using quantitative lung densitometry (qLD). RA patients underwent multi-detector row CT scanning at baseline and after an average of 39 months. Scans were analysed with qLD for the percentage of lung parenchyma with high attenuation areas (%HAA: the percentage of voxels of -600 to -250 Hounsfield units). Additionally, a pulmonary radiologist calculated an expertradiologist scoring (ERS) for RA-ILD features. Generalized linear models were used to identify indicators of baseline %HAA and predictors of %HAA change. Baseline %HAA was assessed in 193 RA patients and 106 had repeat qLD assessment. %HAA was correlated with ERS (Spearman's rho = 0.261; P < 0.001). Significant indicators of high baseline %HAA (>10% of lung parenchyma with high attenuation) included female sex, higher pack-years of smoking, higher BMI and anti-CCP ≥200 units, collectively contributing an area under the receiver operator curve of 0.88 (95% CI 0.81, 0.95). Predictors of %HAA increase, occurring in 49% with repeat qLD, included higher baseline %HAA, presence of mucin 5B (MUC5B) minor allele and absence of HLA-DRB1 shared epitope (area under the receiver operator curve = 0.69; 95% CI 0.58, 0.79). The association of the MUC5B minor allele with %HAA change was higher among men and those with higher cumulative smoking. Within the group with increased %HAA, anti-CCP level was significantly associated with a greater increase in %HAA. %HAA, assessed with qLD, was linked to several known risk factors for RA-ILD and may represent a more quantitative method to identify RA-ILD and track progression than expert radiologist interpretation.

CT Radiomics and Machine-Learning Models for Predicting Tumor-Stroma Ratio in Patients With Pancreatic Ductal Adenocarcinoma.

PurposeTo develop and validate a machine learning classifier based on multidetector computed tomography (MDCT), for the preoperative prediction of tumor–stroma ratio (TSR) expression in patients with pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsIn this retrospective study, 227 patients with PDAC underwent an MDCT scan and surgical resection. We quantified the TSR by using hematoxylin and eosin staining and extracted 1409 arterial and portal venous phase radiomics features for each patient, respectively. Moreover, we used the least absolute shrinkage and selection operator logistic regression algorithm to reduce the features. The extreme gradient boosting (XGBoost) was developed using a training set consisting of 167 consecutive patients, admitted between December 2016 and December 2017. The model was validated in 60 consecutive patients, admitted between January 2018 and April 2018. We determined the XGBoost classifier performance based on its discriminative ability, calibration, and clinical utility.ResultsWe observed low and high TSR in 91 (40.09%) and 136 (59.91%) patients, respectively. A log-rank test revealed significantly longer survival for patients in the TSR-low group than those in the TSR-high group. The prediction model revealed good discrimination in the training (area under the curve [AUC]= 0.93) and moderate discrimination in the validation set (AUC= 0.63). While the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for the training set were 94.06%, 81.82%, 0.89, 0.89, and 0.90, respectively, those for the validation set were 85.71%, 48.00%, 0.70, 0.70, and 0.71, respectively.ConclusionsThe CT radiomics-based XGBoost classifier provides a potentially valuable noninvasive tool to predict TSR in patients with PDAC and optimize risk stratification.

Multi-detector computed tomography for the estimation of sex from sternal medullary cavity measurements in Sudanese individuals

Estimating sex from fragmentary body parts are pivotal for establishing identity. This study assessed the applicability of multidetector computed tomography (MDCT) for determining the dimensions of the sternal medullary cavity for sex estimation in the contemporary Sudanese population. The primary and secondary objectives were to assess the applicability of the sternal medullary cavity dimensions for sex estimation in the Sudanese population using MDCT and to compare the application of discriminant functions and logistic regression in sexing. MDCT scans of 180 adult living subjects (87 males, 93 females; age range 18–90 years) were studied. Two medullary diagonal crossing-length dimensions were measured through the midpoint of the first costal cartilage articular facets. Summary statistical analyses with independent t-test were conducted to assess sexual differences. Discriminant function and logistic regression equations were developed to estimate sex. Statistically significant sexual dimorphism was observed for the three measurements (p < 0.001). For sex determination, binary logistic regression performed better than the discriminant function analysis. The best model predicts sex with a rate of accuracy of 82.8% and a sex bias of 2.3%. Therefore, the medullary diagonal crossing-length dimensions can be used for sexing with high accuracy when more accurate body parts are absent.

Feasibility Study of Ultra-High-Resolution Low-Dose Temporal Bone CT with 1 024×1 024 Reconstruction Matrix Size

To investigate the feasibility of low-dose CT scan of the temporal bone combined with reconstruction matrix size of 1 024×1 024 and the effect of the reconstruction matrix size on image quality. Normal-dose and low-dose bilateral temporal bone CT scans were performed on twelve adult male cadaveric skull specimens using the 160-slice multi-detector CT scanning of United Imaging Healthcare. Normal-dose CT images were reconstructed with matrix sizes of 512×512 and 1 024×1 024, while low-dose CT images were reconstructed with the matrix size of 1 024×1 024. CT value, noise, signal-to-noise ratio, contrast-to-noise ratio, the visualization scoring of 15 anatomical structures of the temporal bone, and the result of three-dimensional reconstruction of the ossicular chain were compared among the three groups. The radiation dose of low-dose CT scanning was reduced by about 50% compared with that of normal-dose CT. There was no significant difference in CT values of air, soft tissues and bones among the three groups. Low-dose temporal bone CT with the matrix size of 1 024×1 024 had higher noise, but much better visualization of temporal bone structure than the normal-dose temporal bone CT with matrix size of 512×512. Both the three-dimensional reconstructions of normal-dose and low-dose 1 024×1 024 matrix images were satisfactory and showed no significant difference. The morphology, size and relative position of malleus, incus, stapes, cochlea, and labyrinth, as well as the location of the ossicular chain in the cranium were all clearly displayed. Low-dose temporal bone CT with the matrix size of 1 024×1 024 can be used to effectively reduce the radiation dose and significantly improve the spatial resolution and the visualization of the temporal bone anatomical structures compared with the normal-dose temporal bone CT with a matrix size of 512×512.