Dual-phase CT Research Articles

A common celiacomesenteric trunk is a rare anatomic variant in dogs.

With the increasing use of CT and MRI for diagnostic imaging and planning of interventional procedures, it is important for veterinary radiologists to be familiar with variations in normal vascular anatomy and not mistake them for pathology. The arterial blood supply to the cranial abdominal viscera is provided by the celiac and the cranial mesenteric arteries. A common celiacomesenteric trunk (CMT) has been reported as a rare anatomical variant in dogs. The goals of this retrospective, observational, cross-sectional prevalence study were to determine the prevalence of a CMT in dogs with non-abdominal disease and compare it to the prevalence in dogs with portosystemic shunts (PSS). Magnetic resonance imaging studies of the thoracolumbar and lumbosacral spine in dogs that included the origin of the celiac and cranial mesenteric arteries and dual-phase CT angiography studies of the abdomen in dogs with portosystemic shunts were retrospectively reviewed by a veterinary student and a board-certified veterinary radiologist. The prevalence of a CMT was determined as the proportion of dogs diagnosed with this vascular anomaly in the MRI and CT group, respectively. Fisher's exact test was used to determine any association of a CMT with the concurrent presence of a PSS, sex, and breed size. A CMT was identified in seven of 606 (1.2%) MRI studies and in none of 47 abdominal CT studies. There was no association between the presence of a CMT and PSS (P=1.000), sex (P=.4694), or breed size (P=1.000). A CMT is a rare incidental finding in dogs.

Value of the application of enhanced CT radiomics and machine learning in preoperative prediction of microvascular invasion in hepatocellular carcinoma

Objective: To explore the value of machine learning models in preoperative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) based on dual-phase contrast-enhanced CT radiomics features. Methods: The data of 148 patients [106 males and 42 females, with an average age of (58±11) years] with HCC confirmed by pathology in the First Affiliated Hospital of Soochow University from January 2015 to May 2020 were retrospectively analyzed, including 88 cases of positive MVI and 60 cases of negative MVI. According to the ratio of 7∶3, the patients were randomly divided into the training and validation sets, respectively. The three-dimensional (3D) radiomics features of HCC in arterial phase (AP) and portal venous phase (PP) were extracted by MaZda software, and the optimal feature subset was obtained by combining three feature selection methods (FPM method) and Lasso regression. Then, six machine learning methods were used to build the prediction models. Receiver operating characteristic (ROC) curves were drawn to evaluate the prediction ability of the aforementioned models, and the area under the curve (AUC), accuracy, sensitivity and specificity were calculated. Results: Radiomics features of HCC in AP and PP were extracted by MaZda software, with 239 in each phase. There were 7 optimal features in AP and 14 optimal features in PP selected by FPM method and Lasso regression, respectively. The AUCs of decision tree, extreme gradient boosting, random forest, support vector machine (SVM), generalized linear model, and neural network based on the 7 optimal features in AP in the validation set were 0.736, 0.910, 0.913, 0.915, 0.897, 0.648, respectively. The SVM had the highest AUC in the validation set, with the accuracy, sensitivity and specificity of 95.35%, 95.83% and 94.74%, respectively. Likewise, the AUCs of machine learning models in prediction of MVI in HCC based on the 14 optimal features in PP in the validation set were 0.873, 0.876, 0.913, 0.859, 0.877, 0.834, respectively, and there were no significant differences (all P>0.05). The random forest had the highest AUC in the validation set, with the accuracy, sensitivity and specificity of 90.70%, 87.50% and 94.74%, respectively. Conclusion: Machine learning models based on dual-phase enhanced CT radiomics features can be used in preoperative prediction of MVI in HCC, particularly the SVM and random forest models have high prediction efficiency.

The diagnostic value of dual-phase cone-beam CT during hepatic arteriography in transarterial chemoembolization for hepatocellular carcinoma.

To evaluate the diagnostic value of dual-phase cone beam CT during hepatic arteriography (CBCTHA) for hepatocellular carcinoma (HCC).Thirty seven patients with unresectable HCC underwent the dual-phase CBCTHA prior to transarterial chemoembolization (TACE). Three blinded observers independently reviewed and compared the first phase CBCTHA images alone and the dual phase CBCTHA images. Diagnostic accuracy was evaluated by the alternative free-response receiver operating characteristic method (Area under the curve: Az value). Sensitivities were analyzed with the paired t test. The analysis was performed for overall HCCs, HCCs up to 1 cm and those larger than 1 cm.For all HCCs and HCCs up to 1 cm, Az value and sensitivity showed no significant difference between the first-phase CBCTHA alone and the dual-phase CBCTHA (Az: 0.81 vs 0.88, P = .07, 0.79 and 0.85, P = .14, sensitivity: 0.61 and 0.73, P = .11, 0.41 and 0.52, P = .33, respectively). For HCCs larger than 1 cm, the mean Az value and sensitivity for the dual-phase CBCTHA were significantly higher than those for the first phase CBCTHA alone (Az: 0.96 vs 0.92, P = .008, sensitivity: 0.85 vs 0.75, P = .013, respectively).The diagnostic accuracy of the dual-phase CBCTHA was superior to that of the first phase CBCTHA alone in the diagnosis of HCC larger than 1 cm.

The appearance of canine insulinoma on dual phase computed tomographic angiography.

To further evaluate the appearance of insulinoma in dogs on dual-phase CT angiography, given the disparity of findings in recent publications. To establish whether CT angiographic localisation of insulinoma correlates with surgical findings. Single centre study of dogs with a final diagnosis of insulinoma which underwent abdominal CT angiography. Scans were retrospectively re-evaluated for specific features by two board-certified veterinary radiologists. These findings were also subsequently compared to surgical and histopathological reports to determine the accuracy of lesion localisation on CT. Thirty-five cases were included in final analysis, with pancreatic nodules identified in 33. Twenty-one were confirmed as insulinoma with histopathology. Jack Russell Terriers were over-represented. Twenty of 21 cases with confirmed insulinoma and 27 of 33 overall showed hyperattenuation in the arterial phase. The mean size of pancreatic insulinoma on CT was 15.1 mm, and 18.2% were larger than 20 mm. Eighteen of 21 confirmed and eight of 12 suspected insulinomas caused a deformation of the pancreatic shape, with two only identified as a result of this feature as these lesions were isoattenuating throughout the study. Pancreatic insulinoma location at surgery matched that described on the CT images in 17 of 19 cases where location was described in the surgical report. In contrast to recent publications, this study suggests hyperattenuation of insulinomas in the arterial phase is a predominant feature, and that hypoattenuation or isoattenuation are much less common. CT angiography is accurate in prediction of lesion location before surgery in most cases.

Adding Delayed Phase Images to Dual-Phase Contrast-Enhanced CT Increases Sensitivity for Small Pancreatic Ductal Adenocarcinoma.

BACKGROUND. Contrast-enhanced CT performed for pancreatic ductal adeno-carcinoma (PDAC) detection traditionally uses a dual-phase (pancreatic and portal venous) protocol. However, PDAC may exhibit isoattenuation in these phases, hindering detection. OBJECTIVE. The purpose of this study was to assess the impact on diagnostic performance in detection of small PDAC when a delayed phase is added to dual-phase contrast-enhanced CT. METHODS. A database of 571 patients who underwent triple-phase (pancreatic, portal venous, and delayed) contrast-enhanced MDCT between January 2017 and March 2020 for suspected pancreatic tumor was retrospectively reviewed. A total of 97 patients had pathologically confirmed small PDAC (mean size, 22 mm; range, 7-30 mm). Twenty control patients had no pancreatic tumor suspected on CT, on initial MRI and follow-up CT, or on MRI after 12 months or longer. Three radiologists independently reviewed dual-phase and triple-phase images. Two additional radiologists assessed tumors' visual attenuation on each phase, reaching consensus for differences. Performance of dual- and triple-phase images were compared using ROC analysis, McNemar test, and Fisher exact test. RESULTS. AUC was higher (p < .05) for triple-phase than dual-phase images for all observers (observer 1, 0.97 vs 0.94; observer 2, 0.97 vs 0.94; observer 3, 0.97 vs 0.95). Sensitivity was higher (p < .001) for triple-phase than dual-phase images for all observers (observer 1, 74.2% [72/97] vs 59.8% [58/97]; observer 2, 88.7% [86/97] vs 71.1% [69/97]; observer 3, 86.6% [84/97] vs 72.2% [70/97]). Specificity, PPV, and NPV did not differ between image sets for any reader (p ≥ .05). Seventeen tumors showed pancreatic phase visual isoattenuation, of which nine showed isoattenuation and eight hyperattenuation in the delayed phase. Of these 17 tumors, 16 were not detected by any observer on dual-phase images; of these 16, six were detected by at least two observers and five by at least one observer on triple-phase images. Visual attenuation showed excellent interob-server agreement (κ = 0.89-0.96). CONCLUSION. Addition of a delayed phase to pancreatic and portal venous phase CT increases sensitivity for small PDAC without loss of specificity, partly related to delayed phase hyperattenuation of some small PDACs showing pancreatic phase isoattenuation. CLINICAL IMPACT. Addition of a delayed phase may facilitate earlier PDAC detection and thus improved prognosis.

Analysis of pancreatic segmentation algorithm based on deep learning to improve pancreatic critical region segmentation ability on dual-phase CT

Objective: To investigate the segmentation effects of the deep learning method on CT in the arterial phase and venous phase respectively by using subjective and objective evaluation system, and to investigate the factors that affect the difference between arterial phase and venous phase pancreas segmentation and the related factors affecting the venous pancreas segmentation. Method: A total of 218 cases of pancreatic CT scan data in the Department of Radiology of Peking Union Medical College Hospital from January to November 2019 were retrospectively collected. Each case contained images of arterial and venous phases, and the data were randomly divided into training set (139 cases), validation set (20 cases) and test set (59 cases) according to the ratio of the training and verification set to the test set of 7∶3. The two-stage global local progressive fusion network was trained on the training set, the model parameters of the optimal segmentation effect were found on the validation set, and the test set was predicted and the results were evaluated subjectively and objectively. The Likert 5-point scale was used for subjective evaluation based on the critical regions between pancreas and peripheral organs, while the Dice similarity coefficient (DSC) was used for objective evaluation. The paired t test or Wilcoxon paired rank test was used to compare the differences of subjective and objective scores of the arterial phase and venous phase. Results: For the critical regions of the pancreas at the duodenum, duodenal jejunal flexure, left adrenal gland, portal vein, superior mesenteric vein, splenic artery and splenic vein, the median number of subjective scores in arterial phase were 4(4, 5), 5(4, 5), 5(4, 5), 4(4, 5), 5(4, 5), 5(5, 5) and 4(3, 5)points respectively, the median number(first quartile, third quartile) of subjective scores in venous phase were 4(4, 4), 5(4, 5), 5(4, 5), 5(4, 5), 5(5, 5), 4(3, 4) and 5(5, 5) points respectively,there were statistically significant differences of the median number(first quartile, third quartile) of the subjective scores between the arterial and venous phase for the critical regions of the pancreas at the organs described above (all P<0.05). DSC in the venous phase was slightly higher than that in the arterial phase and the difference was not statistically significant (DSC: 0.932 vs 0.921, P=0.952). Subjective scores in venous phase of the pancreas and duodenal jejunum, stomach, and left adrenal gland with fat gaps were 4.64,4.68 and 4.63 points respectively, and those of the group without fat gaps were 4.56,4.62 and 4.56 points respectively, there were statistically significant differences of the subjective scores in venous phase of the groups with fat gaps or not between the pancreas and the organs described above (t=2.147, 2.112, 2.277, all P<0.05). Except the spleen, the density differences between the critical regions of the pancreas and other surrounding organs were statistically significant in arterial phase and venous phase segmentation (all P<0.05). Conclusion: Dual-phase CT was used to construct a deep learning automatic pancreas segmentation model, and the segmentation effect was evaluated subjectively and objectively. Subjective evaluation was helpful to improve the ability to segment the critical regions of the pancreas in the future.

CT phenotypes in mild-to-moderate chronic obstructive pulmonary disease: difference before and after the age of 60 years

To investigate the pulmonary phenotype of mild-to-moderate chronic obstructive pulmonary disease (COPD) using quantitative computed tomography CT analysis techniques. Sixty-three patients with stable-phase mild-to-moderate COPD and 78 healthy controls, categorised as those aged <60 (28 and 40 patients, respectively) and ≥60 years (35 and 38, respectively), underwent chest low-dose respiratory dual-phase CT and pulmonary function test. Automatic software was used to measure the proximal airway parameters, and the emphysema and air-trapping indices were recorded. The intergroup differences in each parameter were assessed by one-way analysis of variance. At <60 years of age, the mean Pi10WA (Wall area of a hypothetical airway with an internal perimeter of 10 mm) was greater in the mild-to-moderate COPD group than in the healthy control group (17.04±1.63 versus 16.03±1.16 mm2; p=0.004). Mild or moderate air-trapping was observed in the mild-to-moderate COPD group aged <60 years. There was no significant difference in the proximal airway parameters and inspiratory VI-950 (percent voxels less than -950 HU) between the two groups at age ≥60 years (all p>0.05); however, the expiratory VI-856 (percent voxels less than -856 HU) and mean lung density expiratory/inspiratory ratio (MLDE/I) were higher in the mild-to-moderate COPD group than those in the healthy control group (26.02 [30.23] versus 6.45 [11.16]; 0.88±0.05 versus 0.84±0.04; p<0.001 and p=0.024). For patients with mild-to-moderate COPD, the CT phenotype was predominantly the "airway remodelling" type at <60 years of age, and the "air-trapping" type at ≥60 years of age. Thus, pulmonary CT phenotypes of mild-to-moderate COPD patients of different age groups are different.

Vascular and Parenchymal Enhancement Assessment by Dual-Phase Dual-Energy CT in the Diagnostic Investigation of Pulmonary Hypertension.

To evaluate pulmonary hypertension (PH) determination by dual-phase dual-energy CT pulmonary angiography vascular enhancement and perfused blood volume (PBV) quantification. In this prospective study, consecutive participants who underwent both right heart catheterization and dual-phase dual-energy CT pulmonary angiography were included between 2012 and 2014. CT evaluation comprised a standard pulmonary arterial phase dual-energy CT pulmonary angiography acquisition (termed series 1) followed 7 seconds after series 1 completion by a second dual-energy CT pulmonary angiography acquisition limited to the central 10 cm of the pulmonary vasculature (termed series 2). In both series, enhancement in the main pulmonary artery (PAenh), the descending aorta (DAenh), and whole-lung PBV (WLenh) was calculated from dual-energy CT pulmonary angiography iodine images. Dual-energy CT pulmonary angiography and standard cardiovascular metrics were correlated to mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) with additional receiver operating characteristic curve analysis. A total of 102 participants (median age, 70; range, 58-78 years; 60 women) were included. Sixty-five participants had PH defined by mPAP of greater than or equal to 25 mm Hg, and 51 participants had PH defined by PVR of greater than 3 Wood units. By either definition, participants with PH had higher PAenh/WLenh ratio and lower WLenh and DAenh in series 1 (P < .05) and higher PAenh and WLenh in series 2 (P < .05). Change in WLenh determined highest diagnostic accuracy to define disease by mPAP (area under the receiver operating characteristic curve [AUC], 0.78) and PVR (AUC, 0.79) and the best mPAP correlation (r = 0.62). PAenh series 2 correlated best with PVR (r = 0.49). Multiple linear regression analysis incorporating WLenh and series 1 DAenh improved PVR correlation (r = 0.56). Combining these dual-energy CT pulmonary angiography metrics with main pulmonary artery size and right-to-left ventricular ratio achieved the highest correlations (mPAP, r = 0.71; PVR, r = 0.64). Dual-phase dual-energy CT pulmonary angiography enhancement quantification appears to improve mPAP and PVR prediction in noninvasive PH evaluation.Supplemental material is available for this article.See also the commentary by Kay in this issue.© RSNA, 2020.

Texture analysis of dual-phase contrast-enhanced CT in the diagnosis of cervical lymph node metastasis in patients with papillary thyroid cancer.

Computed tomography texture analysis (CTTA) provides objective and quantitative information regarding tumor heterogeneity beyond visual inspection. However, no study has yet used CTTA to differentiate metastatic from non-metastatic cervical lymph node in patients with papillary thyroid cancer (PTC). To evaluate the value of texture analysis of dual-phase contrast-enhanced CT images in diagnosing cervical lymph node metastasis in patients with PTC. Metastatic (n = 27) and non-metastatic (n = 32) cervical lymph nodes were analyzed retrospectively. Texture analyses were performed on both arterial (A) and venous (V) phase CT images. Texture parameters, including mean gray-level intensity, skewness, kurtosis, entropy, and uniformity, were obtained and compared between groups. Receiver operating characteristic (ROC) curves analyses and multivariate logistic regression analysis were used in our study. Metastatic lymph nodes showed significantly higher A-mean gray-level intensity, A-entropy, and lower A-kurtosis and V-kurtosis (all P < 0.001) than non-metastatic mimics. The ROC curve analyses indicated that A-kurtosis demonstrated an optimal diagnostic area under the curve (AUC; 0.884) and specificity (92.59%), while the A-mean gray-level intensity showed optimal diagnostic sensitivity (90.62%). Multivariate logistic regression analysis showed that A-mean gray-level intensity (P = 0.006, odds ratio [OR] = 24.297) and V-kurtosis (P = 0.014, OR = 19.651) were the independent predictor for metastatic cervical lymph node. Dual-phase contrast-enhanced CCTA-especially A-mean gray-level intensity and V-kurtosis-may have the potential to diagnose metastatic cervical lymph node in patients with PTC.

Revised AAST scale for splenic injury (2018): does addition of arterial phase on CT have an impact on the grade?

To determine whether an additional arterial phase (AP) leads to a change in the grade of splenic injury according to the 2018 revision of the AAST Organ Injury Scale, which has incorporated vascular injuries into the grading system and also to study its impact on management. In this retrospective study, 527 patients who sustained blunt abdominal trauma and had underwent dual-phase CT (AP and portal venous phase (PVP)) from December 2014 to October 2016 (23months) were included. Two experienced radiologists independently graded the splenic injury according to the revised system in 2 blinded ways (AP + PVP and PVP alone). Receiver operator characteristic (ROC) curves were generated for grade of injury on both the phases for all splenic interventions. Splenic injuries were detected in 154 patients, and splenic vascular injuries were detected in 52 of them. Of these, 22 vascular injuries were detected only on the AP, leading to a change in the grade of injury according to the new system in 18 patients. The AUC for ROC curves was generated for the grade of injury on AP + PVP vs. PVP alone for angioembolization (0.80 vs. 0.71, p value 0.002), and all splenic interventions (0.89 vs. 0.83, p value 0.003) showed higher AUC for AP + PVP. Addition of AP leads to a significant change in the grading of splenic injuries according to the revised grading system due to increased detection of vascular injuries. Accurate classification of splenic injuries using additional AP would lead to better triage of patients for splenic interventions or conservative management.

The vessel-depleted neck in head and neck microvascular reconstruction: extreme solutions for extreme situations.

The vessel-depleted neck is the ultimate challenge for the head and neck reconstructive surgeon. In patients who have had previous neck dissections or radiotherapy, the arterial and venous options for future reconstruction can be very limited, and it is important for the surgeon to consider alternative options for vessels. Appropriate preoperative planning is crucial in these patients with a thorough history including previous operation notes, details of previous treatments, and previously used vessels for reconstruction. Clinical examination and a dual phase CT angiogram/MR angiogram can identify vessels available for reconstruction. Arterial options are discussed including tips on using the common carotid artery and the use of Corlett loops for utilizing contralateral arteries. Venous options are also discussed including cephalic vein transposition and Corlett loops. Novel options, such as use of extracorporeal perfusion of flaps have been shown to be effective when all other options have been depleted. Creative solutions are needed for these extreme circumstances, and reconstructive surgeons need to be aware of the options available to select the best one in each case. Careful planning and having multiple back-up choices is crucial to successful reconstruction in these cases.

Comparative analysis and assessment of diagnostic accuracy of 256 slice CT and endoscopic ultrasound in evaluation of pancreatic masses.

Context:Pancreatic masses are routinely encountered on imaging and often present as a diagnostic dilemma. These masses range from benign inflammatory masses, requiring no intervention to malignant masses, which carry grave prognosis and hence require aggressive management.Aims:Compare the diagnostic accuracy of 256 multislice CT and endoscopic ultrasound (EUS) in characterization and assessment of resectability of pancreatic masses and compare the multidetector computed tomography (MDCT) and EUS findings with histopathological findings.Settings and Design:Prospective study.Subjects and Methods:36 patients with pancreatic masses were included who underwent dual phase CT using pancreatic protocol and EUS using 5–13 MHz transducer. Fine needle aspiration cytology (FNAC) was done wherever feasible. Parameters regarding tumor size, location, imaging morphology, and vessel involvement were recorded. Findings were compared with histopathological/operative diagnosis/clinical follow-up.Statistical Analysis Used:Descriptive statistics with percentages and proportions and Chi-square test.Results:Multidetector computed tomography (MDCT) and EUS established diagnosis consistent with tissue diagnosis in 30 (83%) and 22 (61%) patients, respectively. However, the best results were obtained with the combined use of MDCT and EUS. The number of patients categorized as inconclusive by MDCT were lower compared to EUS. Assessing resectability for pancreatic adenocarcinoma, MDCT showed specificity and positive predictive value (PPV) of 100% compared to EUS, which had specificity and PPV of 75% and 92.3%, respectively. MDCT is the first-line imaging modality in detection, characterization of pancreatic masses, and assessment of resectability in malignant neoplasms. EUS is beneficial in the detection of masses <2 cm in size causing pancreatic contour deformity on CT, for guiding FNAC. MDCT and EUS with EUS-guided FNA are complementary not competitive tools in preoperative imaging of pancreatic masses.

Correlation between Spot Sign and Intracranial Hemorrhage Expansion on Dual-Phase CT Angiography.

Purpose: Expansion of intracranial hemorrhage (ICH) is an important predictor of poor clinical outcome. ICH expansion can be predicted with a spot sign on computed tomographic angiography (CTA). We aimed to evaluate the correlation between spot signs on CTA and ICH expansion on dual-phase CTA. Methods: Patients with spontaneous ICH between January 2017 and April 2019 who underwent an initial CT, dual-phase CTA, and a subsequent CT were retrospectively identified. ICH expansion was defined as volume growth of >33% or >6 mL. We analyzed the presence and change in size of the spot sign in the first phase and second phase CTA. Also, we divided the morphological status of the spot sign, such as a dot-like lesion or linear contrast extravasation, in the first and second phase CTA. Results: A total of 206 patients, including 38 (18.5%) with ICH expansion and 45 (21.8%) with a spot sign, qualified for analysis. Of patients with a spot sign, 26 (57.8%) had ICH expansion on subsequent CT. Increased size of a spot sign in second-phase CTA was more frequent in the ICH expansion group than in the no-expansion group (96.2% vs. 52.6%, p < 0.001). First visualization of a spot sign in the second phase was more common in the no-expansion group than in the ICH expansion group (47.4% vs. 3.8%, p < 0.001). The morphological patterns of a spot sign between the two groups were not significantly different. Conclusion: Spot signs on dual-phase CTA have different sizes and morphological patterns. Increased size of a spot sign in the second phase of CTA can help identify patients at risk for ICH expansion.

Dual-phase CT angiography for presurgical planning in patients with vessel-depleted neck.

Microvascular reconstruction in vessel-depleted necks is challenging due to limited availability of recipient vessels. We examine the utility of dual-phase CT angiography (CTA), which delineates both arteries and veins, for preoperative planning in such difficult cases. Retrospective chart review of a single surgeon from July 2013 to July 2017 in a tertiary referral center was performed. Patient characteristics, operative details, and surgical outcomes were examined. Thirteen patients met inclusion criteria. The operative plan was changed to a local flap for one patient as a result of imaging; free tissue transfer was performed for the remaining cases with 100% flap survival rate. Average operative time and ischemia time were 524 ± 110 minutes and 153 ± 47 minutes, respectively. Dual-phase CTA can evaluate potential venous and arterial recipient vessel and guide surgical explorations. As such, it may aid in presurgical planning for microvascular free tissue transfer in vessel-depleted necks.

The hollow adrenal gland sign: a newly described enhancing pattern of the adrenal gland on dual-phase contrast-enhanced CT for predicting the prognosis of patients with septic shock.

To investigate the incidence, CT appearance, and implication for prognosis of the hollow adrenal gland sign (HAGS). A total of 194 patients with septic shock and 24 patients with hemorrhagic shock (as control group) were retrospectively included in this study and the patients with septic shock were further divided into four subgroups (digestive tract diseases, DTD, n = 49; biliary and pancreatic diseases, BPD, n = 41; postsurgical infection, PI, n = 64; and other diseases, OD, n = 40). All patients underwent a dual-phase contrast-enhanced CT within 1week after diagnosis. CT findings and clinical records were reviewed. If in the arterial phase the central zone of adrenal gland showed temporally much lower attenuation than the peripheral zone, it was defined as HAGS positive. The incidence of the HAGS in patients with septic shock and hemorrhagic shock, the demographic features, and mortality between HAGS-positive and HAGS-negative patients in each group were respectively compared. The incidence of the HAGS in the septic shock group was nearly 30%, while it was 0 in the hemorrhagic shock group. There was no significant difference in age or gender between HAGS-positive and HAGS-negative patients in all groups, while the mortality of HAGS-positive patients was significantly higher than that of HAGS-negative patients in each group (p < 0.05). The concordance correlation coefficient value showed excellent reproducibility of the two observers (κ = 0.977). The HAGS is specific and common on dual-phase contrast-enhanced CT in patients with septic shock and predicts a poor prognosis. • The hollow adrenal gland sign (HAGS) newly described in this study is a special enhancing pattern of adrenal gland on dual-phase contrast-enhanced CT in patients with septic shock. • The HAGS is characterized by the much lower-attenuated central zone of the adrenal gland in arterial phase and it showed excellent reproducibility between different observers. • The HAGS is specific and common on dual-phase contrast-enhanced CT in patients with septic shock and predicts a poor prognosis.

Arterial Phase CTA Replacement by a Virtual Arterial Phase Reconstruction from a Venous Phase CTA: Preliminary Results Using Detector-Based Spectral CT.

To assess the feasibility of creating virtual monoenergetic arterial images from venous phase CTA obtained on a detector-based spectral CT scanner and quantitatively compare the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios of the major arteries to those on polyenergetic true arterial phase images. In this retrospective study, 23 patients (15 men and 8 women, median age 68years) who underwent triple-phase CTA on a spectral CT scanner for aortic endograft surveillance were included. The venous phase CTA of each study was reconstructed to generate virtual monoenergetic images at various keV, which were compared to true arterial phase CTA images. SNR and CNR of the aortoiliac arteries were evaluated by testing the differences in means and non-inferiority of virtual arterial images to true arterial images. Effective radiation dose was calculated for standard triple-phase studies in comparison with dual-phase and single-phase spectral CT examinations. Virtual monoenergetic images demonstrated non-inferior (P < 0.05) arterial SNR and CNR compared to true arterial images at 40keV for all arteries, at 45-50keV for the thoracic and suprarenal aorta, and at 45-55keV for the infrarenal aorta and iliac arteries. Significantly higher (P < 0.05) arterial attenuation was obtained at 40keV for the aortoiliac arteries. Mean effective dose for conventional triple-phase studies was 32.5mSv in comparison with 21.3mSv for dual-phase non-contrast/venous scans and 11.3mSv for single-phase venous scans. Detector-based spectral CT enables creation of virtual monoenergetic arterial images from venous phase CTA with equivalent and in some cases significantly higher SNR/CNR of major arteries compared to images from true arterial phase polyenergetic CTA.

Sclerosing Mesenteritis: A Review Article

Sclerosing mesenteritis is a rare chronic inflammatory condition characterized by mesenteric fibrosis. There are three pathological subtypes based on level of inflammation, fat necrosis, and fibrosis: mesenteric panniculitis, mesenteric lipodystrophy, and retractile mesenteritis. The prevalence is 0.6%-1%, with the disease generally affecting middle-aged or older males. There is no known etiology, though there are a variety of potential causal factors. Clinical presentation and dual-phase abdominal CT imaging are occasionally helpful adjuncts to diagnosis, but definitive diagnosis requires surgical biopsy. Management is primarily based on anecdotal evidence, and generally consists of symptomatic treatment via surgical or medical therapy.

Imaging of post-operative pancreas and complications after pancreatic adenocarcinoma resection.

Pancreatic ductal adenocarcinoma is one of the leading causes of cancer-related deaths. With surgical resection being the only definitive treatment, improvements in technique has led to an increase in number of candidates undergoing resection by inclusion of borderline resectable disease patients to the clearly resectable group. Post-operative complications associated with pancreaticoduodenectomy and distal pancreatectomy include delayed gastric emptying, anastomotic failures, fistula formation, strictures, abscess, infarction, etc. The utility of dual-phase CT with multiplanar reconstruction and 3D rendering is increasingly recognized as a tool for the assessment of complications associated with vascular resection and reconstruction such as hemorrhage, pseudoaneurysm, vascular thrombosis, and ischemia. Prompt recognition of the complications and distinction from benign post-operative findings such as hepatic steatosis and mesenteric fat necrosis on imaging plays a key role in helping decrease the morbidity and mortality associated with surgery. We discuss, with case examples, some of such common and uncommon findings on imaging to familiarize the abdominal radiologists evaluating post-operative imaging in both acute and chronic post-operative settings.

Single phase computed tomography is equivalent to dual phase method for localizing hyperfunctioning parathyroid glands in patients with primary hyperparathyroidism: a retrospective review.

ObjectiveThis study aims to compare the sensitivity of dual phase (non-contrast and arterial) versus single phase (arterial) CT for detection of hyper-functioning parathyroid glands in patients with primary hyperparathyroidism.MethodsThe CT scans of thirty-two patients who have biochemical evidence of primary hyperparathyroidism, pathologically proven parathyroid adenomas, and pre-operative multiphase parathyroid imaging were evaluated retrospectively in order to compare the adequacy of single phase vs. dual phase CT scans for the detection of parathyroid adenomas.ResultsThe parathyroid adenomas were localized in 83% of cases on single arterial phase CT and 80% of cases on dual phase CT. The specificity for localization of parathyroid tumor was 96% for single phase CT and 97% for dual phase CT. The results were not significantly different (p = 0.695). These results are similar to those found in the literature for multiphase CT of 55–94%.ConclusionsOur study supports the use of a single arterial phase CT for the detection of hyperfunctioning parathyroid adenomas. Advances in knowledge: a single arterial phase CT has similar sensitivity for localizing parathyroid adenomas as dual phase CT and significantly reduces radiation dose to the patient.

A comparative analysis of dual-phase dual-energy CT and FDG-PET/CT for the prediction of histopathological invasiveness of non-small cell lung cancer

PurposeTo compare dual-phase dual-energy CT (DE-CT) with FDG-PET/CT for predicting histopathological locoregional invasiveness of non-small cell lung cancers (NSCLCs). Materials and methodsWe selected 63 consecutive patients with NSCLC lesions (37 males, 26 females; age range, 44–85 years; mean age, 69 years) who were evaluated preoperatively by both DE-CT and PET/CT at our institution. Postoperative microscopic invasiveness (lymphatic permeation, vascular invasion, and/or pleural involvement) was reviewed, and we defined locoregionally invasive tumors as those that had at least one positive finding of microscopic invasiveness. DE-CT scanning in the arterial and delayed phases was performed after injection of iodinated contrast media using 140-kVp and 80-kVp tube voltages. Three-dimensional iodine-related attenuation of primary tumors in the arterial and delayed phases was quantified automatically using “syngo Dual Energy Lung Nodules” application software, and the ratio of arterial phase to delayed phase enhancement (A/D ratio) was calculated. The A/D ratio and SUVmax on PET/CT were evaluated with respect to postoperative invasiveness by univariate logistic regression analysis. ResultsThe A/D ratio was significantly correlated with lymphatic permeation, vascular invasion, and pleural involvement (p=0.011, p=0.021, and p=0.010, respectively). In contrast, the SUVmax was significantly correlated with pleural involvement (p=0.020) but not with lymphatic permeation or vascular invasion (p=0.088 and p=0.100, respectively). In the subgroup of patients with lesion diameters ≤2cm, the A/D ratio was significantly correlated with locoregional invasiveness (p=0.040), while the SUVmax was not (p=0.121). ConclusionFor the prediction of microscopic invasiveness of NSCLCs, the diagnostic performance of dual-phase DE-CT may be comparable to that of FDG-PET/CT.