Dynamic Contrast-enhanced CT Scans Research Articles

Application of Extended Reality (Virtual Reality and Mixed Reality) Technology in Laparoscopic Liver Resections.

Background and purpose Laparoscopic liver resection (LLR) has recently gained popularity owing to advances in surgical techniques. Difficulties in LLR may be influenced by anatomical factors. This study presents a comprehensive overview of LLR performed using extended reality (XR) technology. Methods Six patients underwent LLR performed wearing HoloLens2® XR (Microsoft Corporation, Redmond, Washington, United States) technology. We performed dynamic contrast-enhanced CT scans before surgery and used the data to construct three-dimensional images. Results Of the six patients, two were diagnosed with colorectal liver metastases, two with hepatocellular carcinoma, and one with intrahepatic cholangiocarcinoma. The median maximum tumor diameter was 31 mm (range, 23-80 mm). One patient had liver cirrhosis, with Child-Pugh classification grade B. Anatomical resection was performed in three patients (60%), with a median difficulty score of 7 (intermediate). No conversions to open surgery were necessary. The median operative time and estimated blood loss were 444 minutes (range, 337-597 minutes) and 200 mL (range, 100-1000 mL), respectively. Postoperative complications (Clavien-Dindo classification grade II) were observed in one patient. All six cases achieved negative surgical margins. Conclusions LLR using XR technology enhances surgical visualization and anatomical recognition. The incorporation of XR technology into LLR offers advantages over traditional two-dimensional imaging.

Combining polyp diameter and polyp-to-bile ratio by dynamic contrast-enhanced CT scanning can improve the diagnostic specificity of gallbladder neoplastic polyps.

This study aimed to distinguish between cholesterol and neoplastic gallbladder polyps using dynamic contrast-enhanced CT. The dataset retrospectively comprised 222 cases, including 106 cases of cholesterol polyps and 116 cases of neoplastic polyps (59 adenoma and 57 adenocarcinoma). The perception and Hounsfield units of the polyps and gallbladder bile were assessed by contrast-enhanced CT, and the polyp-to-bile ratio (PBR) was calculated. Receiver operating characteristic (ROC) curves and area under the curve analyses were used to assess the diagnostic value of the diameter and PBR for neoplastic polyps. The diameter of cholesterol polyps was significantly smaller than that of neoplastic polyps. The proportion of perceived cholesterol polyps in the plain and arterial phases of CT were significantly lower than those of neoplastic polyps (p < .001). On the contrary, the CT values of gallbladder bile of cholesterol polyps were always significantly higher than those of neoplastic polyps (p < .001). The median PBR values of cholesterol polyps were significantly lower than those of neoplastic polyps (p≤.001). ROC analysis showed that diameter and a plain phase PRB had better diagnostic value for neoplastic polyps. Polyp diameter ≥ 11.95 mm and the plain phase PBR ≥1.48 were the optimal cut-off values for diagnosis of neoplastic polyps. Combining a diameter ≥ 12 mm and a PBR in the plain phase ≥1.48 further improved neoplastic polyp diagnostic specificity and positive likelihood ratio (10.453). Polyp-to-bile ratio in contrast-enhanced CT scanning is a new and convenient index for identifying cholesterol and neoplastic gallbladder polyps.

Diagnostic Accuracy of a Convolutional Neural Network Assessment of Solitary Pulmonary Nodules Compared With PET With CT Imaging and Dynamic Contrast-Enhanced CT Imaging Using Unenhanced and Contrast-Enhanced CT Imaging

Solitary pulmonary nodules (SPNs) measuring 8 to 30mm in diameter require further workup to determine the likelihood of malignancy. What is the diagnostic performance of a lung cancer prediction convolutional neural network (LCP-CNN) in SPNs using unenhanced and contrast-enhanced CT imaging compared with the current clinical workup? This was a post hoc analysis of the Single Pulmonary Nodule Investigation: Accuracy and Cost-Effectiveness of Dynamic Contrast Enhanced Computed Tomography in the Characterisation of Solitary Pulmonary Nodules trial, a prospective multicenter study comparing the diagnostic accuracy of dynamic contrast-enhanced (DCE) CT imaging with PET imaging in SPNs. The LCP-CNN was designed and validated in an external cohort. LCP-CNN-generated risk scores were created from the noncontrast and contrast-enhanced CT scan images from the DCE CT imaging. The gold standard was histologic analysis or 2 years of follow-up. The area under the receiver operating characteristic curves (AUC) were calculated using LCP-CNN score, maximum standardized uptake value, and DCE CT scan maximum enhancement and were compared using the DeLong test. Two hundred seventy participants (mean ± SD age, 68.3 ± 8.8 years; 49%women) underwent PET with CT scan imaging and DCE CT imaging with CT scan data available centrally for LCP-CNN analysis. The accuracy of the LCP-CNN on the noncontrast images (AUC, 0.83; 95%CI, 0.79-0.88) was superior to that of DCE CT imaging (AUC, 0.76; 95%CI, 0.69-0.82; P= .03) and equal to that of PET with CT scan imaging (AUC, 0.86; 95%CI, 0.81-0.90; P= .35). The presence of contrast resulted in a small reduction in diagnostic accuracy, with the AUC falling from 0.83 (95%CI, 0.79-0.88) on the noncontrast images to 0.80 to 0.83 after contrast (P< .05 for 240s after contrast only). An LCP-CNN algorithm provides an AUC equivalent to PET with CT scan imaging in the diagnosis of solitary pulmonary nodules. ClinicalTrials.gov Identifier; No.: NCT02013063.

Computed tomography findings of small bowel gastrointestinal stromal tumors with different histologic risks of progression.

The purpose of the study was to assess the dynamic contrast-enhanced computed tomography features of small bowel gastrointestinal stromal tumors with different risks of progression. Forty-two patients with SB GISTs underwent dynamic contrast-enhanced CT scan. All CT features of tumors with different risks were analyzed. The correlation of CT attenuation value in different enhancement phases with different risks was analyzed. In 22 patients, the tumor was in the jejunum, 14 in the ileum, and six in the duodenum. The maximum diameter of the tumors ranged from 1.4 to 21.0cm (median 8.2cm). Histologic risk degree was defined according to pathologic findings (three cases were very low risk, 13 cases were low risk, two cases were intermediate risk, and 24 cases were high risk). For all the risk degrees, there were statistical differences in tumor size, heterogeneity, and presence of necrosis (p<0.05). However, there were no statistical differences in tumor location, presence of calcification, or cystic degeneration (p>0.05). The CT attenuation value of every risk degree was statistically different in venous phase and delayed phase (p<0.05). Features on dynamic contrast-enhanced CT can correlate with SB GISTs of different risk categories which may be helpful for preoperative diagnosis and prognosis evaluation.

Use of patient outcome endpoints to identify the best functional CT imaging parameters in metastatic renal cell carcinoma patients.

To use the patient outcome endpoints overall survival and progression-free survival to evaluate functional parameters derived from dynamic contrast-enhanced CT. 69 patients with metastatic renal cell carcinoma had dynamic contrast-enhanced CT scans at baseline and after 5 and 10 weeks of treatment. Blood volume, blood flow and standardized perfusion values were calculated using deconvolution (BVdeconv, BFdeconv and SPVdeconv), blood flow and standardized perfusion values using maximum slope (BFmax and SPVmax) and blood volume and permeability surface area product using the Patlak model (BVpatlak and PS). Histogram data for each were extracted and associated to patient outcomes. Correlations and agreements were also assessed. The strongest associations were observed between patient outcome and medians and modes for BVdeconv, BVpatlak and BFdeconv at baseline and during the early ontreatment period (p < 0.05 for all). For the relative changes in median and mode between baseline and weeks 5 and 10, PS seemed to have opposite associations dependent on treatment. Interobserver correlations were excellent (r ≥ 0.9, p < 0.001) with good agreement for BFdeconv, BFmax, SPVdeconv and SPVmax and moderate to good (0.5 < r < 0.7, p < 0.001) for BVdeconv and BVpatlak. Medians had a better reproducibility than modes. Patient outcome was used to identify the best functional imaging parameters in patients with metastatic renal cell carcinoma. Taking patient outcome and reproducibility into account, BVdeconv, BVpatlak and BFdeconv provide the most clinically meaningful information, whereas PS seems to be treatment dependent. Standardization of acquisition protocols and post-processing software is necessary for future clinical utilization. Advances in knowledge: Taking patient outcome and reproducibility into account, BVdeconv, BVpatlak and BFdeconv provide the most clinically meaningful information. PS seems to be treatment dependent.

Predicting tumor hypoxia in non-small cell lung cancer by combining CT, FDG PET and dynamic contrast-enhanced CT

Background: Most solid tumors contain inadequately oxygenated (i.e., hypoxic) regions, which tend to be more aggressive and treatment resistant. Hypoxia PET allows visualization of hypoxia and may enable treatment adaptation. However, hypoxia PET imaging is expensive, time-consuming and not widely available. We aimed to predict hypoxia levels in non-small cell lung cancer (NSCLC) using more easily available imaging modalities: FDG-PET/CT and dynamic contrast-enhanced CT (DCE-CT).Material and methods: For 34 NSCLC patients, included in two clinical trials, hypoxia HX4-PET/CT, planning FDG-PET/CT and DCE-CT scans were acquired before radiotherapy. Scans were non-rigidly registered to the planning CT. Tumor blood flow (BF) and blood volume (BV) were calculated by kinetic analysis of DCE-CT images. Within the gross tumor volume, independent clusters, i.e., supervoxels, were created based on FDG-PET/CT. For each supervoxel, tumor-to-background ratios (TBR) were calculated (median SUV/aorta SUVmean) for HX4-PET/CT and supervoxel features (median, SD, entropy) for the other modalities. Two random forest models (cross-validated: 10 folds, five repeats) were trained to predict the hypoxia TBR; one based on CT, FDG, BF and BV, and one with only CT and FDG features. Patients were split in a training (trial NCT01024829) and independent test set (trial NCT01210378). For each patient, predicted, and observed hypoxic volumes (HV) (TBR > 1.2) were compared.Results: Fifteen patients (3291 supervoxels) were used for training and 19 patients (1502 supervoxels) for testing. The model with all features (RMSE training: 0.19 ± 0.01, test: 0.27) outperformed the model with only CT and FDG-PET features (RMSE training: 0.20 ± 0.01, test: 0.29). All tumors of the test set were correctly classified as normoxic or hypoxic (HV > 1 cm3) by the best performing model.Conclusions: We created a data-driven methodology to predict hypoxia levels and hypoxia spatial patterns using CT, FDG-PET and DCE-CT features in NSCLC. The model correctly classifies all tumors, and could therefore, aid tumor hypoxia classification and patient stratification.

Value of multi-slice spiral CT image texture analysis in diagnosing lymphatic metastasis of rectal cancer

Objective To investigate the value of multi-slice spiral CT image texture analysis in differentiating metastatic (MLN) from non-metastatic lymph nodes (NLN) in patients with rectal cancer. Methods Thirty five patients with rectal cancer who were pathologically confirmed by total mesorectum excision were included retrospectively, with regional lymph nodes (short-axis diameter of larger than 3 mm) found in preoperative CT images. All the patients underwent preoperative abdominal and pelvic dynamic contrast-enhanced CT scan. Regional lymph nodes were identified according to pathological findings, and were divided into MLN and NLN groups. The short-axis diameter, short-to long-axis diameter ratio of lymph nodes were manually measured and calculated, and the texture features, including skewness, kurtosis, variance, entropy and inverse difference moment, were analyzed. The above parameters between MLN and NLN groups were compared using independent sample t test or Mann-Whitney U test. ROC curve analysis was performed regarding the statistically significant parameters and the areas under curve (AUC) were calculated. Multivariate Logistic regression analysis was accomplished to obtain the independent predictive factor of diagnosing regional lymph nodes. Results A total of 68 regional lymph nodes were obtained and consisted of 31 MLNs and 37 NLNs. The short-axis diameter, kurtosis, and entropy of the MLN group were significantly higher than those of the NLN group (all P 0.05). The AUC for distinguishing MLN from NLN of the short-axis diameter, kurtosis and entropy were 0.79, 0.67, and 0.85, respectively. Multivariate logistic regression analysis showed that only entropy (odds ratio= 8.48, 95% confidence interval was 3.01 to 23.92, P<0.01) was screened out as the independent variable, which suggested that the entropy was the unique predictor for characterizing regional lymph nodes of rectal cancer. Conclusion Multi-slice spiral CT images texture analysis can facilitate the accurate differentiation between MLN and NLN in patients with rectal cancer, and especially the entropy has the optimal reference significance. Key words: Rectal neoplasms; Lymphatic metastasis; Tomography, X-ray computed; Texture analysis

Triphasic Dynamic Contrast-Enhanced Computed Tomography in the Differentiation of Benign and Malignant Gallbladder Polypoid Lesions

With triphasic, dynamic contrast-enhanced CT scan to identify benign and malignant gallbladder polypoid lesions, we hope to determine an accurate diagnosis before surgery. Ninety patients with gallbladder polypoid lesions were treated surgically in the Department of Hepatobiliary Surgery, the First Affiliated Hospital of China Medical University, Shenyang, China, from July 2013 to July 2016, and divided into 2 groups according to postoperative pathologic results: a malignant group with 44 patients and a benign group with 46 patients. Triphasic, dynamic contrast-enhanced CT scan was performed in 90 patients within 2 weeks before surgery. The CT image parameters were measured and analyzed by 2 senior radiologists and a hepatobiliary surgeon in blind. Mean age of the malignant group was significantly older than that of the benign lesion group (p < 0.01). With the CT image parameters, the maximal diameter of the lesion was significantly longer in malignant lesions than in benign lesions (p < 0.01). There was a significant difference in plain CT, delayed phase CT, and ΔCT values (ΔCT= portal venous phase CT value minus delayed phase CT value) between the 2 groups (all p < 0.01). In terms of differentiating malignant and benign gallbladder polypoid lesions, the ΔCT value was superior to that of plain and delayed phase CT in both sensitivity and specificity (p < 0.05). In triphasic, dynamic contrast-enhanced CT scan, plain CT value, delayed phase CT value, and ΔCT value could detect malignant lesions of gallbladder polyps, with the highest sensitivity and specificity of ΔCT.

Scale-adaptive supervoxel-based random forests for liver tumor segmentation in dynamic contrast-enhanced CT scans.

Toward an efficient clinical management of hepatocellular carcinoma (HCC), we propose a classification framework dedicated to tumor necrosis rate estimation from dynamic contrast-enhanced CT scans. Based on machine learning, it requires weak interaction efforts to segment healthy, active and necrotic liver tissues. Our contributions are two-fold. First, we apply random forest (RF) on supervoxels using multi-phase supervoxel-based features that discriminate tissues based on their dynamic in response to contrast agent injection. Second, we extend this technique in a hierarchical multi-scale fashion to deal with multiple spatial extents and appearance heterogeneity. It translates in an adaptive data sampling scheme combining RF and hierarchical multi-scale tree resulting from recursive supervoxel decomposition. By concatenating multi-phase features across the hierarchical multi-scale tree to describe leaf supervoxels, we enable RF to automatically infer the most informative scales without defining any explicit rules on how to combine them. Assessment on clinical data confirms the benefits of multi-phase information embedded in a multi-scale supervoxel representation for HCC tumor segmentation. Dedicated but not limited only to HCC management, both contributions reach further steps toward more accurate multi-label tissue classification.

Feasibility of triphasic CT with a modified two-point Patlak plot to determine spit kidney glomerular filtration rate in clinical practice.

To investigate whether triphasic CT with a simplified Patlak plot can be used in clinical practice for the estimate of split kidney glomerular filtration rate (SKGFR). The animal experiment included 15 rabbits that underwent 40 dynamic contrast-enhanced CT scans of the kidneys with 1.5s time interval. Patlak-derived SKGFR was obtained using standard forty-point, two-point (unenhanced phase, arterial phase t α, and portovenous phase t β), and a modified two-point (MTP) (unenhanced, t α, t β, and a virtual t τ [t τ=(t α+t β)/2]) image data, respectively. The MTP-Patlak plot approach was then validated in 13 patients who underwent a triphasic renal contrast-enhanced CT examination. SKGFR measured by 99mTc-DTPA clearance was as a standard reference. MTP-Patlak significantly reduced input function errors than two-point Patlak (21.1±16.2% vs 30.8±15.2%, p<0.01) and showed good concordance with standard Patlak for measurement of SKGFR in animal experiment (1.20±0.38mL/g/min vs 1.51±0.43mL/g/min; linear correlation coefficient r=0.87, p<0.001). Human study showed that mean SKGFR was 45.7mL/min (range, 26.5-86.2mL/min) obtained from 99mTc-DTPA, and 38.2mL/min (range, 18.6-79.3mL/min) obtained from triphasic CT using MTP-Patlak plot. Linear correlation between the two methods was r=0.75 (p<0.01). The mean difference between SKGFRs as determined with the two methods was 7.4±9.0mL/min. The MTP-Patlak approach, featured with simplicity, is feasible in a clinically indicated CT examination for the evaluation of split renal function.

Correlation between dynamic contrast-enhanced CT and MRI features of intrahepatic mass-forming cholangiocarcinoma and pathologic differentiation

Objective To investigate the correlation between dynamic contrast-enhanced CT and MRI image findings of intrahepatic mass-forming cholangiocarcinoma(IMCC) and pathologic differentiation. Methods The CT and (or) MRI features of ninety-five patients with IMCC proved by pathologic examination were retrospectively reviewed. Sixty-five patients underwent multiphasic dynamic contrast-enhanced CT scan, twenty-nine underwent multiphasic dynamic contrast-enhanced MRI scan and ten patients underwent multiphasic dynamic contrast-enhanced CT and MRI examination simultaneously. According to the case history and laboratory examination, patients were divided into groups: with chronic hepatitis and without chronic hepatitis and according to the maximum diameter of the tumor, they were divided into 6 cm groups. The imaging features of tumor enhancement were reviewed among groups. The pathologic results and imaging features were compared and patients were divided into well differentiated, moderately differentiated, and poorly differentiated groups. Analyzed by Chi-square test, the difference of tumor enhancement between groups were analyzed. Results The patterns of multiphasic dynamic contrast-enhanced CT and MRI in IMCC patients had five types: type1∶60 cases, peripheral rim and (or) separating enhancement during artery phase, followed by centripetal enhancement progressively and(or) separating enhancement in the equilibrium phase; type 2∶11 cases, peripheral rim enhancement in the artery phase and hypointensity (hypoattenuating) during equilibrium phase with central nodular enhancement; type 3∶15 cases, no enhancement in the arterial phase and internal heterogeneous enhancement during equilibrium phase; type 4∶6 cases, heterogeneous enhancement in the early phase and wash-out during equilibrium phase; type 5∶3 cases, no enhancement throughout dynamic enhancement.The results showed that in hepatitis group type1 to 5 had 31, 7, 12, 5 and 1 cases and without hepatitis group had 29, 4, 3, 1 and 2 cases. There was no statistical significance between groups(χ2=3.567,P=0.059). The maximum diameter 6 cm group(27 cases) had 24, 1, 2, 0 and 0 cases. There was significant difference in groups(χ2=19.582,P<0.01).Pathological well differentiated and moderately differentiated groups(40 cases) had 24, 7,6, 2 and 1 cases presented enhancement type 1 to 5 and poorly differentiated group(55 cases) had 36, 4, 9, 3 and 3 cases. There was no statistical difference in three differentiated groups(χ2=0.296,P=0.586). Conclusions CT and MRI enhancement patterns of IMCC are presented with diversity. The imaging features are associated with focus size and had no relationship with pathological differentiated degree. Key words: Liver neoplasms; Bile duct neoplasms; Tomography, X-ray computed; Magnetic resonance imaging

Comparison of DCE-CT models for quantitative evaluation of Ktrans in larynx tumors

Dynamic contrast enhanced CT (DCE-CT) can be used to estimate blood perfusion and vessel permeability in tumors. Tumor induced angiogenesis is generally associated with disorganized microvasculature with increased permeability or leakage. Estimated vascular leakage (Ktrans) values and their reliability greatly depend on the perfusion model used. To identify the preferred model for larynx tumor analysis, several perfusion models frequently used for estimating permeability were compared in this study. DCE-CT scans were acquired for 16 larynx cancer patients. Larynx tumors were delineated based on whole-mount histopathology after laryngectomy. DCE-CT data within these delineated volumes were analyzed using the Patlak and Logan plots, the Extended Tofts Model (ETM), the Adiabatic Approximation to the Tissue Homogeneity model (AATH) and a variant of AATH with fixed transit time (AATHFT). Akaike’s Information Criterion (AIC) was used to identify the best fitting model. Ktrans values from all models were compared with this best fitting model. Correlation strength was tested with two-tailed Spearman’s rank correlation and further examined using Bland-Altman plots. AATHFT was found to be the best fitting model. The overall median of individual patient medians Ktrans estimates were 14.3, 15.1, 16.1, 2.6 and 22.5 mL/100 g min − 1 for AATH, AATHFT, ETM, Patlak and Logan, respectively. Ktrans estimates for all models except Patlak were strongly correlated (P < 0.001). Bland–Altman plots show large biases but no significant deviating trend for any model other than Patlak. AATHFT was found to be the preferred model among those tested for estimation of Ktrans in larynx tumors.

Evaluation of contrast enhancement and image quality:a comparison between different tube voltages and iodine concentrations in abdominal dynamic CT scans in minipigs

Objective To investigate the effect of tube voltage and iodine concentration of contrast medium (CM) on abdominal dynamic enhanced CT image quality. Methods Six miniature pigs underwent repeated upper abdomen dynamic contrast-enhanced CT scans in 4 scanning protocols with different concentration of CM and tube voltage, namely, protocol 1, CM with iodine concentration of 270 milligrams iodine per milliliter (mg/ml) and 80 kV tube voltage; protocol 2, 270 mg/ml and 120 kV; protocol 3, 370 mg/ml and 80 kV and protocol 4, 370 mg/ml and 120 kV. The same iodine dose (600 mg/ml) and iodine delivery rate (IDR) (920 mg/s) were used in all protocols. The CM with iodine concentration of 270 mg/ml were injected at a flow rate of 3.4 ml/s, and 370 mg/ml CM injected at 2.5 ml/s. Image reconstruction was performed with iterative reconstruction (iDose4) in protocol 1 and 3,filtered back projection (FBP) was used in protocol 2 and 4. A subjective scoring system for image quality, image noise and sharpness was conducted by 2 radiologists independently. The measured values (peak of enhanced CT values, image noise of aorta, inferior vena cava, portal vein, hepatic vein and liver parenchyma) as well as the calculated values [their time-to-peak, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios] were compared between among 4 protocols. The CT volume dose index (CDTIvol) and dose length product (DLP) were recorded from the CT console after each scanning. Factorial designed ANOVA was used for comparison of enhanced CT values of vessels and liver parenchyma, noise, SNR and CNR. The Kruskal-Wallis test was used for comparison of values among the 4 protocols, including the time-to-peak enhancement of vessels and liver parenchyma, the subjective scores of image quality indices. Result There was no significant differences in subjective scores of the image quality, image noise and image sharpness (P>0.05). The scored were more than 3, and the images with 4 scanning protocols were all acceptable for diagnosis. There was no significant differences between protocol 1 and 3, protocol 2 and 4 in the peak enhancement CT values of aorta [(729±46) HU vs.(707±59)HU,(515±84)HU vs. (513±53)HU], inferior vena cava [(366±95)HU vs. (368±92)HU, (282±39)HU vs. (262 ± 67)HU], portal vein [(213 ± 18)HU vs.(201 ± 29)HU, (180 ± 21)HU vs. (176 ± 27)HU], hepatic vein[(207±18)HU vs. (193±10)HU, (179±24)HU vs. (170±14)HU] and liver parenchyma [(128±7) HU vs. (127±4) HU,(135±5)HU vs.(135±6)HU] (P>0.05). But the CT values of vessels (aorta, inferior vena cava, portal vein and hepatic vein) in protocol 1 and 3 were significantly higher than those in protocol 2 and 4 (P 0.05). No significant differences were observed on the peak times, SNR and CNR in aorta, inferior vena cava, portal vein, hepatic vein and liver parenchyma among 4 protocols (P>0.05). The CDTIvol and DLP! were 199.67 mGy, 1 597.4 mGy·cm respectively in protocol 1 and 3,585.12 mGy and 4 680.9 mGy·cm in protocol 2 and 4 (scanning with 120 kV). Conclusions CM with different iodinated concentration could achieve the same enhancement in the abdominal vessels and liver parenchyma by using the proper scan protocols, which have the same IDR and iodine dose per kilogram body weight.Higher vessel enhanced peak values were achieved when using the protocols with 80 kV tube voltage than 120 kV. By using a low dose protocol of 80 kV tube voltage with the iterative reconstruction algorithm, the quality of image can be warranted. Key words: Tomography, X-ray computed; Contrast media; Radiation dosage

Efficacy of the American Association for the Study of Liver Disease and Barcelona criteria for the diagnosis of hepatocellular carcinoma

Dynamic contrast-enhanced CT scan and MRI are essential for preoperative diagnosis of hepatocellular carcinoma (HCC), using the established Barcelona and AASLD criteria, which have been validated in only a few reports. The aim of this study is to retrospectively assess the diagnostic performance of these criteria in diagnosing or excluding HCC in at-risk patients with histopathology confirmation. After institutional review board approval, a HIPAA compliant study was performed. The study cohort consisted of 156 de novo hepatic nodules imaged by either dynamic contrast-enhanced CT or MRI within 90 days of histopathology. Images were retrospectively reviewed by two abdominal radiologists blinded to clinical details, and all nodules were categorized as either meeting or not meeting AASLD and Barcelona criteria. By AASLD or Barcelona criteria, HCC was defined as any nodule greater than or equal to 1 or 2 cm, respectively, with hyperenhancement relative to background liver on arterial phase and hypoenhancement relative to background liver on portal venous or delayed phases. Significant differences in cohorts were analyzed using chi squared analysis (p < 0.05). On biopsy, 141/156 (90.38%) nodules were diagnosed as HCC. The respective sensitivity, specificity, accuracy and positive predictive value of AASLD and Barcelona were 78.7% and 63.1% (sensitivity), 73.3% and 86.7% (specificity), 78.2% and 65.4% (accuracy), and 82% and 63% (positive predictive value) (p < 0.001). Using established imaging criteria, up to 21.8% of presumed HCC nodules are inaccurately characterized and many small HCC nodules remain undiagnosed.

Myomatous hepatic angiomyolipoma: imaging findings in 14 cases with radiological–pathological correlation and review of the literature

To display and analyse the imaging features of myomatous hepatic angiomyolipomas (MHAMLs). The imaging features (CT = 9; MRI = 10; ultrasound = 10; contrast-enhanced ultrasound = 4) of 14 patients with pathologically proven MHAMLs were reviewed retrospectively. MHAMLs were surgically resected in the 14 patients (10 females and 4 males; age, 27-64 years; mean, 45 years), all of whom had negative hepatitis markers and were positive for the immunohistochemical stain homatropine methylbromide-45. The tumours were solitary and well defined, and ranged in size from 1.9 to 9.1 cm (mean, 5.7 cm). On dynamic contrast-enhanced CT, MRI and ultrasound scans, all tumours showed fast strong enhancement in the arterial phase and moderate washout in the portal venous and delayed phases, and the greater portions of the tumours were slightly lower than the surrounding hepatic parenchyma. In some cases, a small area of prolonged or increasing enhancement in the tumour was recognized in the delayed phase. Early draining vessels to the portal vein or hepatic vein could be seen in some cases. However, no capsular signs could be confidently identified in the delayed phase. Haemorrhagic cavities were recognized in two cases, and nodular low-intensity areas in the tumours on T2 weighted imaging that showed slow and faint enhancement on dynamic scans were seen in two cases. However, no necrosis was identified. Dynamic enhanced imaging studies revealed some specific features of MHAMLs that distinguish them from other hypervascular hepatic tumours, especially when combined with clinical features. Familiarity with imaging and clinical features of MHAMLs could avoid unnecessary surgical resection of these generally benign tumours. This article systematically describes the imaging features of MHAMLs.

Septic liver: clinical relevance of early inhomogeneous enhancement of the liver in patients with acute pyelonephritis

CT scans of patients with febrile illness occasionally show hepatobiliary changes, although infection does not originate in the hepatobiliary system. These findings may cause radiologists and clinicians to misrecognize hepatobiliary diseases and initiate an inappropriate treatment. Thus, it is important to recognize hepatobiliary CT findings in cases of extrahepatobiliary infectious disease. To evaluate extrarenal CT manifestations in patients with acute pyelonephritis and to determine the correlation between these extrarenal CT findings and septic liver based on laboratory parameters of sepsis. This study included 157 retrospectively identified patients with confirmed acute pyelonephritis based on CT imaging and urine test, and who had also undergone multi-phase dynamic contrast-enhanced CT scan. Two radiologists reviewed CT findings including early inhomogeneous enhancement of the liver, periportal low density and gallbladder edema, which were correlated with laboratory data including liver function enzymes, albumin, C-reactive protein, white blood cell count, and results of a blood culture by using the Fisher's exact test and Mann-Whitney U test. Forty-six patients (29.3%) showed early inhomogeneous enhancement of the liver, which was associated with increased C-reactive protein (P < 0.001), a positive blood culture (P < 0.005), and decreased albumin level (P < 0.002). The periportal low density and gallbladder wall edema were noted in 15 patients (9.6%) and six patients (3.8%), respectively. These two CT findings were significantly associated with only decreased albumin level (P < 0.001 and P < 0.040). Early inhomogeneous enhancement of the liver in patients with acute pyelonephritis was significantly associated with increased CRP level, a positive blood culture and decreased albumin level, reflecting sepsis and sepsis-associated liver dysfunction, requiring rapid and appropriate intensive treatment.

18F-FDG PET/CT imaging versus dynamic contrast-enhanced CT for staging and prognosis of inflammatory breast cancer

Inflammatory breast cancer (IBC) is the most aggressive type of breast cancer with a poor prognosis. Locoregional staging is based on dynamic contrast-enhanced (DCE) CT or MRI. The aim of this study was to compare the performances of FDG PET/CT and DCE CT in locoregional staging of IBC and to assess their respective prognostic values. The study group comprised 50 women (median age: 51 ± 11 years) followed in our institution for IBC who underwent FDG PET/CT and DCE CT scans (median interval 5 ± 9 days). CT enhancement parameters were net maximal enhancement, net early enhancement and perfusion. The PET/CT scans showed intense FDG uptake in all primary tumours. Concordance rate between PET/CT and DCE CT for breast tumour localization was 92%. No significant correlation was found between SUVmax and CT enhancement parameters in primary tumours (p > 0.6). PET/CT and DCE CT results were poorly correlated for skin infiltration (kappa = 0.19). Ipsilateral foci of increased axillary FDG uptake were found in 47 patients (median SUV: 7.9 ± 5.4), whereas enlarged axillary lymph nodes were observed on DCE CT in 43 patients. Results for axillary node involvement were fairly well correlated (kappa = 0.55). Nineteen patients (38%) were found to be metastatic on PET/CT scan with a significant shorter progression-free survival than patients without distant lesions (p = 0.01). In the primary tumour, no statistically significant difference was observed between high and moderate tumour FDG uptake on survival, using an SUVmax cut-off of 5 (p = 0.7 and 0.9), or between high and low tumour enhancement on DCE CT (p > 0.8). FDG PET/CT imaging provided additional information concerning locoregional involvement to that provided by DCE CT on and allowed detection of distant metastases in the same whole-body procedure. Tumour FDG uptake or CT enhancement parameters were not correlated and were not found to have any prognostic value.

Outcome after Gamma Knife surgery for intracranial arteriovenous malformations in children

The focus of the present study was the evaluation of outcomes after unstaged and staged-volume Gamma Knife surgery (GKS) in children harboring intracranial arteriovenous malformations (AVMs). Twenty-two children (median age 9.5 years) underwent GKS for AVMs and were followed up for at least 2 years thereafter. The disease manifested with intracranial hemorrhage in 77% of cases. In 68% of patients the lesion affected eloquent brain structures. The volume of the nidus ranged from 0.1 to 6.7 cm(3). Gamma Knife surgery was guided mainly by data from dynamic contrast-enhanced CT scans, with preferential targeting of the junction between the nidus and draining vein. The total prescribed isodose volume was kept below 4.0 cm(3), and the median margin dose was 22 Gy (range 20-25 Gy). If the volume of the nidus was larger than 4.0 cm(3), a second radiosurgical session was planned for 3-4 years after the first one. Nine patients in the present series underwent unstaged radiosurgery, whereas staged-volume treatment was scheduled in 13 patients. Complete obliteration of the AVM was noted in 17 (77%) of 22 patients within a median period of 47 months after the last radiosurgical session. Complete obliteration of the lesion occurred in 89% of patients after unstaged treatment and in 62.5% after staged GKS. Four (67%) of 6 high-grade AVMs were completely obliterated. Complications included 3 bleeding episodes, the appearance of a region of hyperintensity on T(2)-weighted MR images in 2 patients who had no symptoms, and reappearance of the nidus in the vicinity of the completely obliterated AVM in 1 patient. Radiosurgery is a highly effective management option for intracranial AVMs in children. For larger lesions, staged GKS may be applied successfully. Initial targeting of the nidus adjacent to the draining vein and application of a sufficient radiation dose to a relatively small volume (≤ 4 cm(3)) provides a good balance between a high probability of obliteration and a low risk of treatment-related complications.

Changes of Tumor Size and Tumor Contrast Enhancement during Radiotherapy for Non-small-cell Lung Cancer May Be Suggestive of Treatment Response

We evaluated sequential dynamic contrast-enhanced CT (DCE-CT) scans to assess the possibility of early prediction of treatment responses by quantifying the tumor size reduction and the change in tumor enhancement during and after a course of radiotherapy (RT). Thirty-nine patients with non-small-cell lung cancer were treated with RT for initial treatment. DCE-CT scan was performed within one week before the beginning of treatment, after 17 or 18 fractions (34 or 36 Gy), and 1 week and 1 month after the end of RT. The correlation between the relative decrease in tumor diameter and that in the attenuation value was evaluated. Nineteen patients were evaluated in this study. The median tumor size was 39.5 mm at the start of treatment, 30.8 mm at 34-36 Gy, and 16.1 mm 1 month after the end of RT. The relative decrease in tumor diameter at 34-36 Gy well correlated with that 1 month after treatment (r = 0.85, r: Pearson's correlation coefficient, p < 0.001). Relative change in the attenuation value at the rim of the tumor at 34-36 Gy did not significantly correlate with the change in tumor diameter 1 month after the completion of RT, but in the center of the tumor, the change of the attenuation value in the delayed phase correlated with the change in tumor diameter. The decrease of tumor diameter during RT may be predictive of treatment response. The relative change of tumor enhancement in the center of the tumor in the delayed phase correlated with tumor shrinkage 1 month after the completion of RT.

Diagnostic value of three dynamic contrast-enhanced spiral CT scan in liver abscess

Objective To explcer spiral CT of the liver abscess performance of dynamic enhanced scanning its diagnostic value. Methods Retrospective analysis of clinical or pathologically confirmed by the 7cases of liver abscess CT, all patients were confirmed by CT scan hepatic arterial phase, portal phase, balance of dynamic contrast-enhanced scan, 1 case of delayed 7 minutes then scan. Results 7 cases of a total of 10liver abscess. Three dynamic enhanced MRI signs:6 typical abscess in four cases,showed double loop sign; an abscess had no enhancement phase enhanced the performance of balance on the edge just to clear; an edge enhancement was tumor sign. 4 cases does not typical abscess in three petal and tumor size sign; a show cluster sign andcontinuing to strengthen the sign, while changing the boundary clear sharp. 4 of 10 abscesses in the liver parenchyma around the abscess,showed a transient arterial phase hepatic enhancement. Conclusion Dynamic contrast-enhanced spiral CT scan phases of liver abscess, especially in atypical liver abscesses had a higher diagnostic value. Key words: Liver abscess ; Tomography, X-ray computed