The purpose of the study was to investigate the imaging and clinical features of xanthogranulomatous pancreatitis (XGP).
MethodsThis retrospective series study included 10 patients with pathology-proven XGP. Two radiologists reviewed the computed tomography (CT) and magnetic resonance imaging (MRI) in consensus to determine the morphological features of XGP. The lesion enhancement pattern on dynamic contrast-enhanced scans and the MR signal intensity were also evaluated. Clinical data including symptoms, underlying pancreatic disease, and laboratory findings were reviewed.
ResultsTwo XGP cases were of a solid type; six were of cystic type, and two were mixed type. XGP usually showed a lobulated contour (90%) and heterogeneous enhancement (100%), with lesion size varying from 2 to 11 cm. Perilesional infiltration was common (90%), but pancreatic duct dilatation was less frequent (30%). Cystic type XGP mostly had an irregular thick wall (83%). On dynamic contrast-enhanced CT/MRI, XGP enhanced progressively from arterial to portal or delayed phases. Lesions appeared hypointense on T1-weighted images (89%) and hyperintense on T2-weighted images (100%). All lesions appeared hyperintense on diffusion-weighted images, with the majority (78%) showing diffusion restriction on apparent diffusion coefficient maps. The patients often had abdominal pain (80%) and underlying pancreatic disease (80%), but mostly had normal or clinically insignificant laboratory findings.
ConclusionsXGP typically manifests as a clinically silent lobulated heterogeneous mass, with a progressive enhancement pattern and/or irregular thick wall, and diffusion restriction on CT/MRI. Awareness of the imaging and clinical features of XGP may help differentiate it from pancreatic neoplasms, thereby reducing unnecessary surgery.
相似文献To assess the diagnostic performance of simultaneous whole-body 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) positron emission tomography (PET)/magnetic resonance imaging (MRI) compared to [18F]FDG PET/x-ray computed tomography (CT) for detection of distant metastatic disease in patients with malignant melanoma.
ProceduresWe included patients with malignant melanoma who underwent a single injection [18F]FDG dual-imaging protocol that included whole-body PET/CT and subsequent whole-body PET/MRI for staging or restaging purposes in a prospective setting. Images from both modalities were analyzed by two rater teams for the presence of metastatic lesions. PET/CT–PET/MRI overall agreement as well as region-based accuracies, sensitivities (Se), and specificities (Sp) were computed.
ResultsBetween July 2014 and December 2018, 22 patients were enrolled. Interrater agreement and overall accuracy (consensus reading) were 78.8 % (95 % CI 71–84.9) and 96.1 % (95 % CI 92.3–98) for PET/MRI and 78 % (70.2–84.3) and 97.4 % (95 % CI 93.7–98.9) for PET/CT, respectively (P?=?0.42). PET/MRI reached a region-based Se of 89.1 % (95 % CI 79.4–94.5) and a Sp of 100 %, whereas PET/CT showed a region-based Se of 92.7 % (95 % CI 84–96.9) and a Sp of 100 % for the detection of metastatic disease in malignant melanoma.
ConclusionsWhole-body [18F]FDG-PET/MRI appears to be comparable to [18F]FDG-PET/CT for lesion detection in patients with malignant melanoma.
相似文献To evaluate the imaging features of hepatic segmental atrophy and nodular elastosis.
Materials and methodsIn this Institutional review board (IRB)-approved, HIPAA-compliant study, we reviewed imaging features in six cases of histologically confirmed hepatic segmental atrophy (HSA) and nodular elastosis (NE). Retrospective review of ultrasound (US) in 2 patients, computed tomography (CT) in 5 patients, magnetic resonance imaging (MRI) in 4 patients, and positron emission tomography (PET) in 2 patients was performed. Location, size, and attenuation/density/signal intensity of these lesions were evaluated. Clinical presentation and coexistent conditions were also recorded.
ResultsAll six patients were females. Mean age of presentation was 58.3 years (range 37–80). A single HSA and NE lesion in each patient was found. The mean size of the lesion was 18 mm (range: 3 mm to 36 mm). Most lesions were detected incidentally (5/6). On contrast-enhanced single-phase (portal venous) CT, most lesions were hypodense (4/5) and one lesion was hyperdense to fatty liver parenchyma. On MRI, the lesions were iso- to hyperintense on T2-weighted images, T1 hypointense, and hyperintense on diffusion-weighted images (DWI). Three lesions were hypointense on arterial, portal venous, and delayed phases. One lesion occurring in fatty liver appeared hyperintense on all three phases. Gd-EOB-DTPA-enhanced images were available in 2 patients and lesions were hypointense on the 20-min hepatobiliary phase. On PET, two lesions were isometabolic to the background hepatic parenchyma. On ultrasound, one lesion appeared hypoechoic and another lesion isoechoic to hepatic parenchyma.
ConclusionsHepatic segmental atrophy and nodular elastosis is an uncommon benign lesion and can simulate metastases due to variable imaging features. Lack of FDG uptake on PET/CT may be a clue to the benign nature of the lesion and may suggest the possibility of HSA and NE.
相似文献Blood flow reduction after initiation of lenvatinib therapy may not always indicate tumor necrosis. This study aimed to compare the blood flow detectability of contrast-enhanced ultrasonography (CEUS), contrast-enhanced computed tomography (CT), and contrast-enhanced magnetic resonance imaging (MRI) in hepatocellular carcinoma (HCC) during lenvatinib therapy.
MethodsA total of 12 cases underwent CEUS and contrast-enhanced CT/MRI within 2 weeks during lenvatinib therapy. Vascularity on CEUS and CT/MRI was compared.
ResultsAt the time of CEUS examination, the median period from the start of lenvatinib was 227?±?210 (31–570) days. CEUS showed hyperenhancement in eight cases (66.7%), hypoenhancement in two cases (16.7%), and no enhancement in one case (8.3%), while CT/MRI showed hyperenhancement in one case (8.3%), ring enhancement in three cases (25.0%), and hypoenhancement in eight cases (66.7%) (p?=?0.007). Transarterial chemoembolization (n?=?3), radiofrequency ablation (n?=?2), and stereotactic body radiation therapy (n?=?2) were performed after blood flow detection by CEUS.
ConclusionsThe viability of the HCC should be confirmed using CEUS when contrast-enhanced CT/MRI reveals lesion hypoenhancement during lenvatinib therapy.
相似文献To prospectively compare multidetector-row CT (MDCT) and MR imaging (MRI) in the assessment of the ablative margin (AM) and index tumor immediately after radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) and assess whether non-contrast MRI with limited sequences (T1- and T2-weighted imaging only) was superior to a conventional MDCT protocol.
MethodsA total of 33 consecutive patients with 42 HCCs were included in this study. Both MDCT and MR images were independently reviewed by two radiologists regarding the ability to visually discriminate between the AM and index tumor, and the AM status within ablation zones. The AM status was classified as AM-plus (AM completely surrounding the tumor), AM-zero (AM was partly discontinuous, without protrusion of the tumor), and AM-minus (AM was partly discontinuous, with protrusion of the tumor). During the follow-up period, the cumulative local tumor progression rates were analyzed using the Kaplan–Meier method and Cox proportional hazards model. To determine the added value of contrast-enhanced MR images, both reviewers separately evaluated the two sets (unenhanced and enhanced) of MR images.
ResultsVisual discrimination between the AM and index tumor was possible in four (9.5%) and 34 (81%) of the 42 ablation zones using MDCT and MRI, respectively (p < 0.001). Thirty-eight and four cases were classified as AM-plus and AM-zero on MDCT images, respectively, whereas the ablation zones were categorized as AM-plus (n = 32), AM-zero (n = 9), and AM-minus (n = 1) when examining the MR images. The cumulative incidence of local tumor progression was significantly lower in cases with AM-plus on MRI (p = 0.007). Contrast-enhanced MRI had no added value for the assessment of the AM and index tumor.
ConclusionMRI was superior to MDCT for the differential assessment of the AM and index tumor immediately after RF ablation for HCC. Non-contrast MRI was also superior to the conventional MDCT protocol.
相似文献The purpose of the study was to examine the diagnostic and prognostic values of 18F-fluorothymidine (FLT)-PET/CT for pancreatic cancer by comparing with 18F-fluorodeoxyglucose (FDG)-PET/CT.
MethodsFifteen patients with newly diagnosed pancreatic cancer underwent both FLT and FDG-PET/CT scans before treatment. The sensitivity, specificity, and accuracy in detecting nodal and distant metastases were compared between both scans using McNemar exact or χ 2 test. Progression-free survival (PFS) and overall survival (OS) were calculated by Kaplan–Meier method. Prognostic significance was assessed by Cox proportional hazards analysis.
ResultsBoth scans visualized all primary cancers. The sensitivity, specificity, and accuracy per patient basis for detecting nodal metastasis were equal and 63.6% (7/11), 100% (4/4), and 73.3% (11/15) for both scans, and for detecting distant metastasis were 100% (6/6), 88.9% (8/9), and 93.3% (14/15) for FDG-PET/CT, and 50.0% (3/6), 100% (9/9), and 80.0% (12/15) for FLT-PET/CT, respectively, without significant difference in each of them between both scans (p > 0.05). However, of 4 patients with multiple liver metastases, FDG-PET/CT was positive in all, but FLT-PET/CT was negative in three patients. At univariate analysis, only FLT-SUVmax correlated with PFS (hazard ratio, 1.306, p = 0.048), and FDG total lesion glycolysis (TLG), FLT-SUVmax, and FLT-total lesion proliferation (TLP) correlated with OS (p = 0.021, p = 0.005, and p = 0.022, respectively). At bivariate analysis, FLT-SUVmax was superior to FDG-TLG or FLT-TLP for prediction of OS [HR (adjusted for FDG-TLG), 1.491, p = 0.034, HR (adjusted for FLT-TLP), 1.542, p = 0.023].
ConclusionFLT-PET/CT may have a potential equivalent to FDG-PET/CT for detecting primary and metastatic cancers except liver metastasis. FLT-SUVmax can provide the most significant prognostic information.
相似文献The purpose of the study was to assess the feasibility and diagnostic performance of FDG-PET/MR imaging compared to PET/CT for staging of patients with a gynecological malignancy.
Methods25 patients with a gynecological malignancy were prospectively enrolled into this pilot study. Patients underwent sequential full-body PET/CT and PET/MR of the abdomen and pelvis after administration of a single dose of F-18 FDG. PET/MRI and PET/CT images were independently reviewed by two expert radiologists. Readers were blinded to the results of the other imaging procedures. Clinical and pathologic information was abstracted from medical charts.
Results18 patients were included in the final analysis with a median age of 62 years (range 31–88). 61% of patients (11/18) had cervical cancer, while the remaining patients had endometrial cancer. PET/MRI as compared to PET/CT detected all primary tumors, 7/7 patients with regional lymph nodes, and 1/1 patient with an abdominal metastasis. Two patients had additional lymph nodes outside of the abdominopelvic cavity detected on PET/CT that were not seen on PET/MRI, whereas 6 patients had parametrial invasion and one patient had invasion of the bladder seen on PET/MRI not detected on PET/CT. Five cervical cancer patients had discordant clinical vs. radiographic staging based on PET/MRI detection of soft tissue involvement. Management changed for two patients who had clinical stage IB1 and radiographic stage IIB cervical cancer.
ConclusionsPET/MRI is feasible and has at least comparable diagnostic ability to PET/CT for identification of primary cervical and endometrial tumors and regional metastases. PET/MRI may be superior to PET/CT for initial radiographic assessment of cervical cancers.
相似文献The purpose of the study was to correlate lung shunt fraction (LSF) calculated by intra-arterial injection of Technetium-99m (Tc-99m)-labeled macroaggregated albumin (MAA) in a hepatic artery branch with the presence of certain patterns of vascular shunts on dynamic CT or MRI of the liver.
MethodsThis retrospective study was approved by the institutional review board and informed consent was waived. We reviewed 523 MAA scans in 453 patients (301 men, 152 women) performed from July 2007 to June 2015 and their correlative cross-sectional imaging. Patterns of vascular shunts on dynamic CT or MRI performed within 3 months of the MAA study and that potentially divert hepatic arterial inflow to the systemic venous return were defined as “target shunts.” Dynamic CT or MRI was classified into three groups with target shunt present, absent, or indeterminate. The mean LSF was compared across the first and second groups using paired t test.
Results342 CT and MRI studies met inclusion criteria: target shunts were present in 63 studies, absent in 271 studies, and 8 studies were indeterminate. When target shunts were visualized, the mean LSF on corresponding MAA scans was 12.9 ± 10.36% (95% CI 10.29–15.15%) compared to 4.3 ± 3.17% (95% CI 3.93–4.68%) when no target shunt was visualized. The difference was statistically significant (p value < 0.001). Identified target shunts were either direct (arteriohepatic venous shunt) or indirect (arterioportal shunt combined with a portosystemic shunt).
ConclusionsVisualizing certain patterns of vascular shunting on a dynamic CT or MRI scan is associated with high LSF.
相似文献The purpose of our study was to retrospectively evaluate and categorize temporal changes in MRI appearances of the prostate in patients who underwent focal therapy with MRI follow-up.
MethodsThe Institutional Review Board approved this retrospective study and waived the requirement for informed consent. Thirty-seven patients (median age 61; 48–70 years) with low-to-intermediate-risk, clinically organ-confined prostate cancer underwent focal ablation therapy from 2009 to 2014. Two radiologists reviewed post-treatment MRIs (n = 76) and categorized imaging features blinded to the time interval between the focal therapy and the follow-up MRI. Inter-reader agreement was assessed (kappa) and generalized linear regression was used to examine associations between an imaging feature being present/absent and days between ablation and MRI.
ResultsInter-reader agreement on MRI features ranged from fair to substantial. Edema was found present at earlier times after ablation (median 16–25 days compared to MRIs without edema, median 252–514 days), as was rim enhancement of the ablation zone (18–22.5 days vs. 409–593 days), a hypointense rim around the ablation zone on T2-weighted images (53-57.5 days vs. 279–409 days) and the presence of an appreciable ablation cavity (48.5–60 days vs. 613–798 days, all p < 0.05). Enhancement of the ablation zone/scar (553–731 days vs. 61.5–162 days) and the formation of a T2-hypointense scar were found to be present on later MRI scans (514–553 days vs. 29–32 days, one reader).
ConclusionsThe MRI appearance of the prostate after focal ablation changes substantially over time. Identification of temporal patterns in the appearance of imaging features should help reduce image interpretation variability and errors when assessing post-therapeutic scans.
相似文献To evaluate the impact of complex-averaging on image quality (IQ) and diagnostic accuracy of acquired and calculated high b value (aHBV, cHBV) images in diffusion-weighted prostate MRI.
Materials and methodsThis retrospective study included 84 patients who underwent multiparametric prostate MRI at 3 Tesla without endorectal coil. DWIs were acquired at three different b values which included two lower b values (b = 50,900 s/mm2) and one higher b value (aHBV at 2000 s/mm2). The acquired data were postprocessed to generate two different types of trace-weighted images—using conventional magnitude-averaging and complex-averaging. Using lower b values (b = 50,900 s/mm2) from both conventional and complex-averaged image sets, cHBV images (b = 2000 s/mm2) and ADC maps were derived. All image sets were reviewed by two radiologists in different reading sessions to assess image quality and PIRADS. The diagnostic accuracy of different image sets for the detection of prostate lesions was performed by correlating PIRADS and Gleason scores.
ResultsComplex-averaging did not impact ADC values of the prostate lesions compared to magnitude-averaging (P = 0.08). Complex-averaging improved image quality of acquired high b value and calculated high b value images (P < 0.0001). Complex-averaging also improved the level of confidence (LOC) of the acquired high b value for both readers (P < 0.0001, P < 0.05), but only for reader A in calculated high b value (P < 0.0001). The image quality of calculated high b value images was not significantly different than acquired high b value images. The dataset combining complex-averaging and calculated high b value provided the highest diagnostic accuracy (but not statistically significant) for detection of the significant prostate lesion compared to the magnitude-averaged acquired high b value (79.55% vs. 72.73%; P = 0.317). The mean acquisition time for b = 2000 s/mm2 sequence (aHBV) was 6 min 30 s (± 1 min 16 s) out of a total of 28 min 31 s (± 4 min 26 s) for the entire mp-MRI protocol (approximately 25% of total scan time).
ConclusionComplex-averaging provides better image quality and level of confidence without significant impact on ADC values and diagnostic accuracy for detection of the significant prostate lesions . The calculated high b value images are also comparable to (and can substitute) the acquired high b value images which can help in reducing the imaging time.
相似文献To assess the diagnostic performance of the apparent diffusion coefficient (ADC) in predicting the Fuhrman nuclear grading of clear cell renal cell carcinomas (ccRCC).
Materials and methodsA total of 129 patients who underwent partial and radical nephrectomies with pathology-proven ccRCC were retrospectively evaluated. Histopathological characteristics and nuclear grades were analyzed. In addition, conventional magnetic resonance imaging (MRI) features were assessed in consensus by two radiologists to discriminate nuclear grading. ADC values were obtained from a region of interest (ROI) measurement in the ADC maps calculated from diffusion-weighted imaging (DWI) using b values of 50, 500, and 800 s/mm2. The threshold values for predicting and differentiating low-grade cancers (Fuhrman I–II) from high grade (Fuhrman III–IV) was obtained using binary logistic regression. The ADC cut-off value for differentiating low- and high-grade tumors was determined using classification analysis.
ResultsSignificant associations (P < 0.001) were found between nuclear grading, conventional MR features, and DWI. Hemorrhage, necrosis, perirenal fat invasion, enhancement homogeneity, and cystic component were identified as independent predictors of tumor grade. High-grade ccRCC had significantly lower mean ADC values compared to low-grade tumors. An ADC cut-off value of 1.6 × 10−3 mm2/s had an optimal predictive percentage of 65.5% for low-grade tumors above this threshold and 81% for high-grade ccRCC below this threshold. Overall predictive accuracy was 70.5%.
ConclusionThe addition of ADC values to a model based on MRI conventional features demonstrates increased sensitivity and high specificity improving the distinguishing accuracy between both high-grade and low-grade ccRCC.
相似文献The aim of this study was to evaluate the utility of added DWI sequences as an adjunct to traditional MR imaging in the evaluation of abnormal placentation in patients with suspicion for placenta accreta spectrum abnormality or morbidly adherent placenta (MAP).
Materials and methodsThe study was approved by local ethics committee. The subjects included pregnant women with prenatal MRI performed between July 2013 to July 2015. All imaging was performed on a Philips 1.5T MR scanner using pelvic phased-array coil. Only T2-weighted and diffusion-weighted imaging (DWI) series were compiled for review. Two randomized imaging sets were created: set 1 included T2-weighted series only (T2W); set 2 included T2W with DWI series together (T2W + DWI). Three radiologists, blinded to history and pathology, reviewed the imaging, with 2 weeks of time between the two image sets. Sensitivity, specificity, and overall accuracy for MAP were calculated and compared between T2W only and T2W + DWI reads. Associations between imaging findings and invasion on pathology were tested using the Chi-squared test. Confidence scores, inter-reader agreement, and systematic differences were documented.
ResultsA total of 17 pregnant women were included in the study. 8 cases were pathologically diagnosed with MAP. There were no significant differences in the diagnostic accuracy between T2W and T2W + DWI in the diagnosis of MAP in terms of overall accuracy (62.7% for T2W vs. 68.6% for T2W + DWI, p = 0.68), sensitivity (70.8% for T2W vs. 95.8% for T2W + DWI, p = 0.12), and specificity (55.6% for T2W vs. 44.4% for T2W + DWI, p = 0.49). There was no significant difference in the diagnostic confidence between the review of T2W images alone and the T2W + DWI review (mean 7.3 ± 1.8 for T2W vs. 7.5 ± 1.8 for T2W + DWI, p = 0.37).
ConclusionWith the current imaging technique, addition of DWI sequence to the traditional T2W images cannot be shown to significantly increase the accuracy or reader confidence for diagnosis of placenta accreta spectrum abnormality. However, DWI does improve identification of abnormalities in the placental–myometrial interface.
相似文献The purpose of the study is to propose a computed tomography (CT) classification of spontaneous isolated superior mesenteric artery dissection (SISMAD) correlated with clinical presentation
MethodsWe retrospectively reviewed CT images of 40 patients with SISMAD at our institution from 2006 to 2015 and proposed a new classification: type I, patent false lumen with both entry and re-entry; type II, patent false lumen without re-entry; type III, completely or partially thrombosed false lumen; and type IV, thrombosed false lumen with ulcer-like projection. Additionally, we included a subtype (S) at each type when there was either a long segment of dissection and/or significant true lumen stenosis. CT features were statistically analyzed using Fisher’s exact and Mann–Whitney test.
ResultsThe CT findings classified patients as type I (15%), type II (12.5%), type III (35%), and type IV (37.5%). Of the 40 patients, 25 (62.5%) were symptomatic. There was a significantly different proportion of each type between symptomatic and asymptomatic patients (p = 0.005). There were 25 patients with subtype (S); no type I or II, 12 type III, and 13 type IV. The symptomatic patients showed longer dissection tendency and more severe true lumen stenosis (78% vs. 53%, p = 0.000) compared with asymptomatic patients.
ConclusionThe proposed multi-detector CT classification of SISMAD correlates with clinical presentation. This new classification could be helpful for treatment planning.
相似文献To evaluate whole-lesion ADC histogram metrics for assessing the malignant potential of pancreatic intraductal papillary mucinous neoplasms (IPMNs), including in comparison with conventional MRI features.
MethodsEighteen branch-duct IPMNs underwent MRI with DWI prior to resection (n = 16) or FNA (n = 2). A blinded radiologist placed 3D volumes-of-interest on the entire IPMN on the ADC map, from which whole-lesion histogram metrics were generated. The reader also assessed IPMN size, mural nodularity, and adjacent main-duct dilation. Benign (low-to-intermediate grade dysplasia; n = 10) and malignant (high-grade dysplasia or invasive adenocarcinoma; n = 8) IPMNs were compared.
ResultsWhole-lesion ADC histogram metrics demonstrating significant differences between benign and malignant IPMNs were: entropy (5.1 ± 0.2 vs. 5.4 ± 0.2; p = 0.01, AUC = 86%); mean of the bottom 10th percentile (2.2 ± 0.4 vs. 1.6 ± 0.7; p = 0.03; AUC = 81%); and mean of the 10–25th percentile (2.8 ± 0.4 vs. 2.3 ± 0.6; p = 0.04; AUC = 79%). The overall mean ADC, skewness, and kurtosis were not significantly different between groups (p ≥ 0.06; AUC = 50–78%). For entropy (highest performing histogram metric), an optimal threshold of >5.3 achieved a sensitivity of 100%, a specificity of 70%, and an accuracy of 83% for predicting malignancy. No significant difference (p = 0.18–0.64) was observed between benign and malignant IPMNs for cyst size ≥3 cm, adjacent main-duct dilatation, or mural nodule. At multivariable analysis of entropy in combination with all other ADC histogram and conventional MRI features, entropy was the only significant independent predictor of malignancy (p = 0.004).
ConclusionAlthough requiring larger studies, ADC entropy obtained from 3D whole-lesion histogram analysis may serve as a biomarker for identifying the malignant potential of IPMNs, independent of conventional MRI features.
相似文献To determine the value of CEUS for real-time, fusion-guided, percutaneous biopsies of focal liver lesions.
Materials and methodsInstitutional review board approval and written informed consents were obtained for this study. Forty patients with focal liver lesions identified on CT/MRI were prospectively enrolled. For biopsy planning, real-time fusion of CT/MRI with USG (USG-Fusion) was performed, and subsequently real-time CEUS was fused with CT/MRI (CEUS-Fusion). We evaluated lesion visibility, confidence level of technical success before the procedure, and safety route accessibility on USG-Fusion and CEUS-Fusion. Occurrence of change in the biopsy target was also assessed.
ResultsAmong 40 target lesions, nine (22.5%) lesions were invisible on USG-Fusion. After applying CEUS-Fusion, seven of nine (77.8%) lesions were visualized. Confidence level of technical success of procedure was significantly increased on CEUS-Fusion compared USG-Fusion (p = 0.02), and presumed target lesions were changed in 16 (40%) patients after CEUS-Fusion. As the lesion is necrotic, presumed target was more frequently changed after CEUS-Fusion (50.0% and 25.0%). Confirmative diagnostic results were reported in 39 (97.5%) patients. Accessibility of the safety route to target lesions did not reach statistical differences.
ConclusionApplying a new, real-time CEUS-Fusion with CT/MRI improved tumor visibility and viable portion assessment, thus leading to higher operator confidence and diagnostic yield, when compared with conventional USG-Fusion.
相似文献To determine the diagnostic potential of Material Density (MD) iodine images in dual-energy CT (DECT) for visualization and quantification of arterial phase hyperenhancement and washout in hepatocellular carcinomas compared to magnetic resonance imaging (MRI).
Materials and MethodsThe study complied with HIPAA guidelines and was approved by the ethics committee of the institutional review board. Thirty-one patients (23 men, 8 women; age range, 36–87 years) with known or suspected Hepatocellular Carcinoma (HCC) were included. All of them underwent both single-source DECT and MRI within less than 3 months. Late arterial phase and portal venous phase CT imaging was performed with dual energies of 140 and 80 kVp, and virtual monoenergetic images (at 65 keV) and MD-iodine images were generated. We determined the contrast-to-noise ratio (CNR) for HCC in arterial phase and portal venous phase images. In addition, we introduced a new parameter which combines information of CNR in arterial and portal venous phase images into a single ratio (combined CNR). All parameters were assessed on monoenergetic 65 keV images, MD-iodine images, and MRI. Paired t test was used to compare CNR values in Mono-65 keV, MD-iodine, and MR images.
ResultsCNR was significantly higher in the MD-iodine images in both the arterial (81.87 ± 40.42) and the portal venous phases (33.31 ± 27.86), compared to the Mono-65 keV (6.34 ± 4.23 and 1.89 ± 1.87) and MRI (30.48 ± 25.52 and 8.27 ± 8.36), respectively. Combined CNR assessment from arterial and portal venous phase showed higher contrast ratios for all imaging modalities (Mono-65 keV, 8.73 ± 4.03; MD-iodine, 119.87 ± 52.94; MRI, 34.87 ± 27.34). In addition, highest contrast ratio was achieved in MD-iodine images with combined CNR evaluation (119.87 ± 52.94, P < 0.001).
ConclusionMD-iodine images in DECT allow for a quantitative assessment of contrast enhancement and washout, with improved CNR in hepatocellular carcinoma in comparison to MRI.
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