Factors predicting aggressiveness of non-hypervascular hepatic nodules detected on hepatobiliary phase of gadolinium ethoxybenzyl diethylene-triamine-pentaacetic-acid magnetic resonance imaging

AIM: To establish a prognostic formula that distinguishes non-hypervascular hepatic nodules(NHNs) with higher aggressiveness from less hazardous one. METHODS: Seventy-three NHNs were detected in gadolinium ethoxybenzyl diethylene-triamine-pentaaceticacid magnetic resonance imaging(Gd-EOB-DTPA-MRI) study and confirmed to change 2 mm or more in size and/or to gain hypervascularity. All images were interpreted independently by an experienced, board-certified abdominal radiologist and hepatologist; both knew thatthe patients were at risk for hepatocellular carcinoma development but were blinded to the clinical information. A formula predicting NHN destiny was developed using a generalized estimating equation model with thirteen explanatory variables: age, gender, background liver diseases, Child-Pugh class, NHN diameter, T1-weighted imaging/T2-weighted imaging detectability, fat deposition, lower signal intensity in arterial phase, lower signal intensity in equilibrium phase, α-fetoprotein, des-γ-carboxy prothrombin, α-fetoprotein-L3, and coexistence of classical hepatocellular carcinoma. The accuracy of the formula was validated in bootstrap samples that were created by resampling of 1000 iterations. RESULTS: During a median follow-up period of 504 d, 73 NHNs with a median diameter of 9 mm(interquartile range: 8-12 mm) grew or shrank by 68.5%(fifty nodules) or 20.5%(fifteen nodules), respectively, whereas hypervascularity developed in 38.4%(twenty eight nodules). In the fifteen shrank nodules, twelve nodules disappeared, while 11.0%(eight nodules) were stable in size but acquired vascularity. A generalized estimating equation analysis selected five explanatories from the thirteen variables as significant factors to predict NHN progression. The estimated regression coefficients were 0.36 for age, 6.51 for lower signal intensity in arterial phase, 8.70 or 6.03 for positivity of hepatitis B virus or hepatitis C virus, 9.37 for des-γ-carboxy prothrombin, and-4.05 for fat deposition. A formula incorporating the five coefficients revealed sensitivity, specificity, and accuracy of 88.0%, 86.7%, and 87.7% in the formulating cohort, whereas these of 87.2% ± 5.7%, 83.8% ± 13.6%, and 87.3% ± 4.5% in the bootstrap samples. CONCLUSION: These data suggest that the formula helps Gd-EOB-DTPA-MRI detect a trend toward hepatocyte transformation by predicting NHN destiny.

Magnetic resonance imaging of the cirrhotic liver: An update

Noninvasive imaging has become the standard for hepatocellular carcinoma(HCC) diagnosis in cirrhotic livers. In this review paper, we go over the basics of MR imaging in cirrhotic livers and describe the imaging appearance of a spectrum of hepatic nodules marking the progression from regenerative nodules to low- and high-grade dysplastic nodules, and ultimately to HCCs. We detail and illustrate the typical imaging appearancesof different types of HCC including focal, multifocal, massive, diffuse/infiltrative, and intra-hepatic metastases; with emphasis on the diagnostic value of MR in imaging these lesions. We also shed some light on liver imaging reporting and data system, and the role of different magnetic resonance imaging(MRI) contrast agents and future MRI techniques including the use of advanced MR pulse sequences and utilization of hepatocyte-specific MRI contrast agents, and how they might contribute to improving the diagnostic performance of MRI in early stage HCC diagnosis.

Differentiation between dysplastic nodule and early-stage hepatocellular carcinoma: The utility of conventional MR imaging

AIM:To elucidate the variety of ways early-stage hepatocellular carcinoma(HCC)can appear on magnetic resonance(MR)imaging by analyzing T1-weighted,T2-weighted,and gadolinium-enhanced dynamic studies.METHODS:Seventy-three patients with well-differentiated HCC(wHCC)or dysplastic nodules were retrospectively identified from medical records,and new histological sections were prepared and reviewed.The tumor nodules were categorized into three groups:dysplastic nodule(DN),wHCC compatible with Edmondson-Steiner grade I HCC(w1-HCC),and wHCC compatible with Edmondson-Steiner gradeⅡHCC(w2-HCC).The signal intensity on pre-contrast MR imaging and the enhancing pattern for each tumor were recorded and compared between the three tumor groups.RESULTS:Among the 73 patients,14 were diagnosed as having DN,40 were diagnosed as having w1-HCC,and 19 were diagnosed as having w2-HCC.Hyperintensity measurements on T2-weighted axial images(T2WI)were statistically significant between DNs and wHCC(P=0.006)and between DN and w1-HCC(P=0.02).The other imaging features revealed no significant differences between DN and wHCC or between DN and w1-HCC.Hyperintensity on both T1W out-phase imaging(P=0.007)and arterial enhancement on dynamic study(P=0.005)showed statistically significant differences between w1-HCC and w2-HCC.The other imaging features revealed no significant differences between w1-HCC and w2-HCC.CONCLUSION:In the follow-up for a cirrhotic nodule,increased signal intensity on T2WI may be a sign of malignant transformation.Furthermore,a noted loss of hyperintensity on T1WI and the detection of arterial enhancement might indicate further progression of the histological grade.

Quantitative differentiation of malignant and benign thyroid nodules with multi-parameter diffusion-weighted imaging

BACKGROUND The value of conventional magnetic resonance imaging in the differential diagnosis of thyroid nodules is limited;however,the value of multi-parameter diffusion-weighted imaging(DWI)in the quantitative evaluation of thyroid nodules has not been well determined.AIM To determine the utility of multi-parametric DWI including mono-exponential,biexponential,stretched exponential,and kurtosis models for the differentiation of thyroid lesions.METHODS Seventy-nine patients(62 with benign and 17 with malignant nodules)underwent multi-b value diffusion-weighted imaging of the thyroid.Multiple DWI parameters were obtained for statistical analysis.RESULTS Good agreement was found for diffusion parameters of thyroid nodules.Malignant lesions displayed lower diffusion parameters including apparent diffusion coefficient(ADC),the true diffusion coefficient(D),the perfusion fraction(f),the distributed diffusion coefficient(DDC),the intravoxel water diffusion heterogeneity(α)and kurtosis model-derived ADC(Dapp),and higher apparent diffusional kurtosis(Kapp)than benign entities(all P<0.01),except for the pseudodiffusion coefficient(D*)(P>0.05).The area under the ROC curve(AUC)of the ADC(0 and 1000)was not significantly different from that of the ADC(0 and 2000),ADC(0 to 2000),ADC(0 to 1000),D,DDC,Dapp and Kapp(all P>0.05),but was significantly higher than the AUC of D*,f andα(all P<0.05)for differentiating benign from malignant lesions.CONCLUSION Multiple DWI parameters including ADC,D,f,DDC,α,Dapp and Kapp could discriminate benign and malignant thyroid nodules.The metrics including D,DDC,Dapp and Kapp provide additional information with similar diagnostic performance of ADC,combination of these metrics may contribute to differentiate benign and malignant thyroid nodules.The ADC calculated with higher b values may not lead to improved diagnostic performance.

Diffusion-weighted magnetic resonance imaging with short T1 inversion recovery-echo planar imaging combined with dual-head coincidence single photon emission computed tomography for diagnosing solitary pulmonary nodule

Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） can depict many of the lesions depicted with a PET scanner in the lungs, which is used in place of PET-CT for discriminating malignant from benign pulmonary nodules in many studies. However, DHC-SPECT has inevitable false-negative results because the sensitivity for small lesions less than 2.0 cm is limited, and has high false-positive rate for active inflammatory nodules. Furthermore,DHC-SPECT also has a considerably higher cost （$300 in China） than other imaging examination.

Diffusion-weighted images(DWI) without ADC values in assessment of small focal nodules in cirrhotic liver

Objective： To assess if diffusion-weighted magnetic resonance （MR） imaging without apparent diffusion coefficient （ADC） values provides added diagnostic value in combination with conventional MR imaging in the detection and characterization of small nodules in cirrhotic liver. Methods： Two observers retrospectively and independently analyzed 86 nodules （_〈3 em） certified pathologically in 33 patients with liver cirrhosis, including 48 hepatocellular carcinoma （HCC） nodules, 13 high-grade dysplastic nodules （HDN）, 10 low-grade dysplastic nodules （LDNs） and 15 other benign nodules. All these focal nodules were evaluated with conventional MR images （Tl-weighted, T2-weighted and dynamic gadolinium-enhanced images） and breath-hold diffusion-weighted images （DWI） （b=500 s/mm2）. The nodules were classified by using a scale of 1-3 （1, not seen; 3, well seen） on DWI for qualitative assessment. These small nodules were characterized by two radiologists. ADC values weren＇t measured. The diagnostic performance of the combined DWI-conventional images and the conventional images alone was evaluated using receiver operating characteristic （ROC） curves. The area under the curves （Az）, sensitivity and specificity values for characterizing different small nodules were also calculated. Results： Among 48 HCC nodules, 33 （68.8%） were graded as 3 （well seen）, 6 （12.5%） were graded as 2 （partially obscured）, and 9 weren＇t seen on DWI. Among 13 HDNs, there were 3 （23.1%） and 4 （30.8%） graded as 3 and 2 respectively. Five （50%） of 10 benign nodules were partially obscured and slightly hyperintense. For 86 nodules, the average diagnostic accuracy of combined DWI-conventional images was 82.56%, which was increased significantly compared with conventional MR images with 76.17%. For HCC and HDN, the diagnostic accuracy of combined DWI-conventional images increased from 78.69% to 86.07 %. Conclusions： Diffusion-weighted MR imaging does provide added diagnostic value in the detection and characterization of HDN and HCC, and it may not be helpful for LDN and regenerative nodule （RN） in cirrhotic liver.

Solitary fibrous tumors in abdomen and pelvis:Imaging characteristics and radiologic-pathologic correlation

AIM: To describe the imaging features of solitary fibrous tumors (SFTs) in the abdomen and pelvis, and the clinical and pathologic correlations.

Comparison of Various Parameters of DWI in Distinguishing Solitary Pulmonary Nodules

In order to prospectively assess various parameters of diffusion weighted imaging (DWI)in differential diagnosis of benign and malignant solitary pulmonary nodules (SPNs),58 patients (40 men and 18 women,and mean age of 48.1±10.4years old) with SPNs undergoing conventional MR,DWI using b=500s/mm^2 on a 1.5T MR scanner, were studied.Various DWI parameters [apparent diffusion coefficient (ADC),lesion-to-spinal cord signal intensity ratio (LSR),signal intensity (SI)score] were calculated and compared between malignant and benign SPNs groups.A receiver operating characteristic (ROC)curve analysis was employed to compare the diagnostic capabilities of all the parameters for discrimination between benign and malignant SPNs.The results showed that there were 42 malignant and 16 benign SPNs.The ADC was significantly,lower in malignant SPNs (1.40±0.44)×10^-3mm^2/s than in benign SPNs (1.81±0.58)×10^-3mm^2/ s.The LSR and SI scores were significantly increased in malignant SPNs (0.90±0.37 and 2.8±1.2)as compared with those in benign SPNs (0.68±0.39 and 2.2±1.2).The area under the ROC curves (AUC)of all parameters was not significantly different between malignant SPNs and benign SPNs.It was suggested that as three reported parameters for DWI,ADC,LSR and SI scores are all feasible for discrimination of malignant and benign SPNs.The three parameters have equal diagnostic performance.

Dynamic contrast-enhanced MRI versus ^(18)F-FDG PET/CT: Which is better in differentiation between malignant and benign solitary pulmonary nodules?

Objective： To prospectively compare the discriminative capacity of dynamic contrast enhanced-magnetic resonance imaging（DCE-MRI） with that of^18F-fluorodeoxyglucose（^18F-FDG） positron emission tomography/computed tomography（PET/CT） in the differentiation of malignant and benign solitary pulmonary nodules（SPNs）.Methods： Forty-nine patients with SPNs were included in this prospective study. Thirty-two of the patients had malignant SPNs, while the other 17 had benign SPNs. All these patients underwent DCE-MRI and ^18F-FDG PET/CT examinations. The quantitative MRI pharmacokinetic parameters, including the trans-endothelial transfer constant（K^trans）, redistribution rate constant（Kep）, and fractional volume（Ve）, were calculated using the Extended-Tofts Linear two-compartment model. The ^18F-FDG PET/CT parameter, maximum standardized uptake value（SUV（max））, was also measured. Spearman＇s correlations were calculated between the MRI pharmacokinetic parameters and the SUV（max） of each SPN. These parameters were statistically compared between the malignant and benign nodules. Receiver operating characteristic（ROC） analyses were used to compare the diagnostic capability between the DCE-MRI and ^18F-FDG PET/CT indexes.Results： Positive correlations were found between K^trans and SUV（max）, and between K（ep） and SUV（max）（P〈0.05）.There were significant differences between the malignant and benign nodules in terms of the K^trans, K（ep） and SUV（max） values（P〈0.05）. The areas under the ROC curve（AUC） of K^trans） K（ep） and SUV（max） between the malignant and benign nodules were 0.909, 0.838 and 0.759, respectively. The sensitivity and specificity in differentiating malignant from benign SPNs were 90.6% and 82.4% for K^trans; 87.5% and 76.5% for K（ep）; and 75.0% and 70.6%for SUV（max）, respectively. The sensitivity and specificity of K^trans and K（ep） were higher than those of SUV（max）, but there was no significant difference between them（P〉0.05）.Conclusions： DCE-MRI can be used to differentiate between benign and malignant SPNs and has the advantage of being radiation free.

BLOOD FLOW PATTERN AND QUANTITATIVE STUDY IN SOLITARY PULMONARY NODULES WITH DYNAMIC CONTRAST-ENHANCED MRI

Objective To evaluate the efficacy of contrast enhanced dynamic MRI in differentiating solitary pulmonary nodules（SPNs）. Methods Eighty-three patients with SPNs undertaken contrast enhanced dynamic MRI. Time-signal intensity curve （T-SI Curve） was made. Peak height （PH） , steepest slope （SS）, maximum enhancement （ Emax ） and the enhancement rates of signal intensity were recorded at the frst （ E1 ）, second （ E2 ）, third （ E3 ） , fourth （ E4 ） , fifth （E5）, and sixth （ E6 ） minute after injection. Results Malignant nodules and inflammatory nodules enhanced significantly higher than benign nodules, and malignant nodules and inflammatory nodules showed obviously higher PH, SS, Emax, El-E6 values than benign nodules （ P 〈 0. 01 ）. There were no sig- nificant differences in PH, SS, Emax, E1-E6 values between malignant nodules and inflammatory nodules （P 〉 0. 05）. Conclusion Contrast enhanced dynamic MR imaging can provide SPNs＇ hemodynamic information and is helpful in differentiating SPNs.

Decision-tree analysis for cost-effective management of solitary pulmonary nodules in China

AIM: To analyze the cost-effectiveness of the diagnosis of solitary pulmonary nodule(SPN) in China. METHODS: Decision analysis models were constructed to assess the cost-effectiveness of four strategies for the management of SPN: computed tomography(CT) alone, CT plus CT-guided automated cutting needle biopsy(ACNB), CT plus positron emission tomography/computed tomography(PET/CT), CT plus diffusionweighted magnetic resonance imaging(DWI) plus PET/CT. RESULTS: The prevalence of lung cancer among SPN discovered in the clinical setting was approximately 50%. The CT plus ACNB strategy had higher diagnostic accuracies(87% vs 81%), with a cost saving of $1945 RMB per patient, and reducing unnecessary thoracotomy by 16.5%; this was associated with a 4.5% missed diagnosis rate. CT plus DWI plus PET/CT strategy also had higher accuracies(95% vs 81%), with a cost saving of $590 RMB per patient, and reducing unneces-sary thoracotomy by 13.5%; this was accompanied by 0.3% missed diagnosis rate. CT plus PET strategy is cost effective at a prevalence rate of 0-34%, but there was a larger prevalence range of lung cancer for CT plus ACNB strategy(from 0 to 0.6) and CT plus DWI plus PET/CT strategy(from 0 to 0.64). CONCLUSION: CT plus DWI plus PET/CT strategy was cost-effective, and had a higher accuracy accompanied by a lower missed diagnosis rate than CT plus ACNB strategy.

Macro-regenerative nodules in biliary atresia:CT/MRI findings and their pathological relations

AIM: To describe the radiological findings of a macro-regenerative nodule (MRN) in the liver of pre-transplantation biliary atresia (BA) patients and to correlate it with histological findings. METHODS: Between August 1990 and November 2007, 144 BA patients underwent liver transplantation (LT) at our institution. The pre-transplantation computer tomograghy (CT) and magnetic resonance imaging (MRI) findings were reviewed and correlated with the post-transplantation pathological findings. RESULTS: Nine tumor lesions in 7 patients were diagnosed in explanted livers. The post-transplantation pathological findings showed that all the lesions were MRNs without malignant features. No small nodule was detected by either MRI or CT. Of the 8 detectable lesions, 6 (75%) were in the central part of the liver, 5 (63%) were larger than 5 cm, 5 (63%) had intra- tumor tubular structures, 3 (38%) showed enhancing fibrous septa, 3 (38%) had arterial enhancement in CT, one (13%) showed enhancement in MRI, and one (13%) had internal calcifications. CONCLUSION: Although varied in radiological appearance, MRN can be differentiated from hepatocellular carcinoma (HCC) in most of BA patients awaiting LT. The presence of an arterial-enhancingnodule does not imply that LT is withheld solely on the basis of presumed malignancy by imaging studies. Liver biopsy may be required in aid of diagnostic imaging to exclude malignancy.

Pancreatic fluid collections: What is the ideal imaging technique?

Pancreatic fluid collections(PFCs) are seen in up to 50% of cases of acute pancreatitis. The Revised Atlanta classification categorized these collections on the basis of duration of disease and contents, whether liquid alone or a mixture of fluid and necrotic debris. Management of these different types of collections differs because of the variable quantity of debris; while patients with pseudocysts can be drained by straight-forward stent placement, walledoff necrosis requires multi-disciplinary approach. Differentiating these collections on the basis of clinical severity alone is not reliable, so imaging is primarily performed. Contrast-enhanced computed tomography is the commonly used modality for the diagnosis and assessment of proportion of solid contents in PFCs; however with certain limitations such as use of iodinated contrast material especially in renal failure patients and radiation exposure. Magnetic resonance imaging(MRI) performs better than computed tomography(CT) in characterization of pancreatic/peripancreatic fluid collections especially for quantification of solid debris and fat necrosis(seen as fat density globules), and is an alternative in those situations where CT is contraindicated. Also magnetic resonance cholangiopancreatography is highly sensitive for detecting pancreatic duct disruption and choledocholithiasis. Endoscopic ultrasound is an evolving technique with higher reproducibility for fluid-to-debris component estimation with the added advantage of being a single stage procedure for both diagnosis(solid debris delineation) and management(drainage of collection) in the same sitting. Recently role of diffusion weighted MRI and positron emission tomography/CT with ^(18)F-FDG labeled autologous leukocytes is also emerging for detection of infection noninvasively. Comparative studies between these imaging modalities are still limited. However we look forward to a time when this gap in literature will be fulfilled.

MR Features of Regenerative Nodules and Dysplastic Nodules in the Cirrhotic Liver

Summary： In order to study MR features of the regenerative nodule （RN） and dysplastic nodule （DN） of the cirrhotic liver, 26 cases of cirrhotic liver with RNs and DNs, of which 8 cases accompanied with hepatocellular carcinoma, were subjected to MRI. Eighteen of 26 cases underwent additional enhanced MRI with administration of Gd-DTPA on T1WI and 10 of the 18 cases did additional SPIO （Feridex） enhancement on T2W1. Clinical data showed normal level of α-fetoprotein in 18 cases except 8 cases accompanied with HCC. The results showed that 12 cases had RNs with nodules measuring 〈1 cm. The MR appearance of those RNs showed isointensity on T1WI and hypointensity on T2WI. The intensity of those RNs was isointense to the surrounding hepatic parenchyma on enhanced MRI with administration of Gd-DTPA or SPIO. Among the 14 cases of DNs, 8 cases had nodules measuring 1-3 cm in size and 6 had macroregenerative nodule measuring 〉3 cm. In 8 cases with DNs measuring 1-3 cm in size, 5 cases appeared hyperintense on T1W1 and hypointense on T2W1 as well as the enhancement as that of nodules with （1 cm in size; and the remaining 3 cases appeared hypointense on T1WI and hyperintense on T2WI, and were not isointense to the surrounding hepatic parenchyma on enhanced MRI but hyperintense on SPIO enhanced MRI. In 6 cases of macroregenerative nodule measuring 2〉3 cm in size, 2 cases appeared hyperintense to the surrounding hepatic parenchyma on T1, T2WI and enhanced MRI; 4 cases showed hyperintense on TlWI, and hypointense on T2WI and enhanced MRI. Sometimes, normal vessels were seen to pass through the surface of macroregenerative nodules. It was suggested that RNs of cirrhosis had features on MRI that usually allow distinction from hepatocellular carcinoma but not always from dysplastic nodules （DNs）. A helpful distinction between HCC and DNs is that the latter are almost never hyperintense on T2WI. Additionally, low grade DNs appear hypoimense on SPIO enhanced MR1.

Difference Analysis of MRI Apparent Diffusion Coefficient and R_(2)^(*)Value Between Small Hepatocellular Carcinoma and Cirrhosis Nodules

Objective:To investigate the differences of apparent diffusion coefficient and transverse relaxation rate(R_(2)^(*))in magnetic resonance imaging(MRI)between micro hepatocellular carcinoma and nodules of cirrhosis.Method:The clinical data of 68 patients with micro hepatocellular carcinoma(76 lesions)and 45 patients with nodular cirrhosis(48 lesions)were retrospectively analyzed.Diffusion weighted imaging and R_(2)^(*)imaging were performed on all patients.The differences of apparent diffusion coefficient and R_(2)^(*)values in patients with micro hepatocellular carcinoma and nodular cirrhosis were compared.Receiver operating characteristic(ROC)curves were drawn to evaluate the diagnostic efficacy of apparent diffusion coefficient values and R_(2)^(*)values for microhepatocellular carcinoma.Result:Compared with nodules of cirrhosis,the mean apparent diffusion coefficient and R_(2)^(*)value of micro-hepatocellular carcinoma were significantly decreased(P<0.05).The diagnosis threshold of apparent diffusion coefficient is at 1.35×10^(-3)mm^(2)/s,and the sensitivity for the diagnosis of micro-hepatocellular carcinoma was 80.88%,and the specificity was 91.11%,and the corresponding area under the ROC curve was 0.88;The diagnostic threshold for R_(2)^(*)value was at 53.96 Hz,and the sensitivity for the diagnosis of small hepatocellular carcinoma was 91.18%,and the specificity was 77.78%,and the corresponding area under the ROC curve was 0.84.Conclusion:MRI apparent diffusion coefficient value and R_(2)^(*)value can be used to differentiate and diagnose micro hepatocellular carcinoma and nodules of cirrhosis,in which the apparent diffusion coefficient of nodules of cirrhosis was less than 1.35×10^(-3)mm^(2)/s,R_(2)^(*)values were lower than 53.96 Hz may indicate the occurrence of nodular canceration.

Intrathoracic solitary fibrous tumor: a report of 3 cases and review of the literature

Objective: The aim of this study was to investigate the imaging findings of intrathoracic solitary fibrous tumor (SFT), so as to improve its diagnosis and differential diagnosis. Methods: The clinical, imaging and pathological data of three intrathoracic SFTs confirmed by surgical pathology were analyzed retrospectively. There three cases all received spiral CT plain scan and enhanced scan, among which two multi-planar reformation (MPR) and one MR plain scan. And literatures were reviewed to investigate the imaging findings of intrathoracic SFT. Results: The three intrathoracic SFT located at intra-pulmonary, oblique fissure pleura and posterior chest wall visceral pleura, respectively. All were solitary masses. One case was a peripheral lung mass at dorsal segment of left lower lobe which CT plain scan showed as a soft tissue mass well circumscribed, enhanced scan showed that there were enhanced clustered, lineal small vascular signs in the mass during arterial phase, delayed scanning displayed that the mass showed heterogeneous enhancement and parts of solid content showed gradual enhancement, and there were shorter T1 signals on MRI T1WI, map-like high-low mixed signals on T2WI, mainly with short T2 signals. One case was an oblique fissure mass which plain scan showed as a homogeneous soft tissue mass with oval in shape and smooth edge, and enhanced scan showed moderate homogeneous enhancement. One case was a mass localized at posterior chest wall visceral pleura which CT plain scan showed as a heterogeneous mass, and enhanced scan showed that there was slight ring-like enhancement, large non-enhancing necrosis area in the mass and facing vessels in the vicinity region. All these three cases had no hilar and mediastinal lymphadenectasis. Operation and pathology results showed that the mass was well circumscribed, with capsule or false capsule. Under microscope, tumor cells were long fusiform, presenting bundle, turbulence or irregular arrangement. Hypocellular and hypercellular area appeared alternately, with interspersed coarse scar-like collagen fibers with hyalinization. There were hemangiopericytoma-like structures under parts of visual fields. There were bronchiole and alveolar epithelium in the legion at dorsal segment of left lower lobe in one case. The results of immunohistochemistry showed that the expressions of CD34 or CD99, Bcl-2 and vimentin were all strong positive. Conclusion: Intrathoracic SFT might be rare, which imaging findings could have relative characteristic features and diagnosis must depend on histopathology and immunohistochemistry examination.

孤立性纤维瘤的CT和MRI特征分析

目的 探讨孤立性纤维瘤(SFT)的CT及MRI特征,并与病理对照分析其特点。方法 选取经手术病理及免疫组化证实的SFT患者14例,所有病例均行CT检查,其中5例行MRI检查,12例行增强扫描。结果 1)发生部位:病变位于颅内2例,胸部4例,纵隔1例,盆腔4例,腹股沟1例,腹膜后1例,胰腺1例;2)肿块大小:最大径2.7~15.5 cm;3)肿块的密度和信号:14例中3例密度及信号均匀,11例表现为不均匀,1例肿瘤内见脂肪成分,CT平扫11例为等密度,3例为稍低密度;MRI平扫T_(1)WI主要为等及稍低信号,T_(2)WI为等及稍高信号,肿瘤信号不均则表现为T_(1)WI和T_(2)WI混杂信号;4)肿瘤形态及边缘:肿瘤呈圆形、类圆形及椭圆形9例,不规则形3例,分叶状2例,其中10例边缘光整,4例边缘不光整;5)肿瘤的强化:7例为明显强化,3例为中度强化,2例为边缘环形强化,其中1例为均匀强化,11例为不均匀强化或地图样强化,8例可见肿瘤内或周边多发强化小血管影,5例可见肿瘤内多发囊变;6)免疫组化:所有病例的CD34、STAT6、CD99、bcl-2、Vimentin的阳性率均较高。结论 SFT多数为较大的圆形或类圆形肿块,密度不均匀,肿瘤内部及周边常见小血管影及囊变。增强后肿瘤多表现为明显不均匀强化,强化程度可能与肿瘤内细胞、胶原纤维及血管的生长方式有关,肿瘤的密度、信号及强化特征与病理成分具有相关性,二者结合分析可提高对该病的诊断水平。

DCE-MRI定量参数联合小视野弥散加权成像对甲状腺良恶性结节鉴别的价值

目的探讨动态对比增强磁共振成像(dynamic contrast-enhanced magnetic resonance imaging,DCE-MRI)定量参数联合小视野弥散加权成像在甲状腺良恶性结节鉴别中的应用价值。材料与方法收集2022年1月至2023年10月于滨州医学院附属医院诊治并经手术病理证实为甲状腺结节的患者38例(52个结节),将其分为良性结节组和恶性结节组。术前患者均行3.0 T MRI扫描,包括常规MRI、小视野弥散加权成像(b值取0、800 s/mm^(2))和DCE-MRI检查,并测量其表观弥散系数(apparent diffusion coefficient,ADC)值和DCE-MRI定量参数,包括对比剂容积转运常数(volume transport constant,K^(trans))、速率常数(rate constant,K_(ep))、血管外细胞外间隙容积分数(extravascular extracellular volume fraction,V_(e))。对甲状腺良恶性结节组的ADC、K_(ep)、V_(e)、K^(trans)采用独立样本t检验分析,以P<0.05为差异有统计学意义,后将差异有统计学意义的变量进行逐步logistic回归模型分析,得到甲状腺良恶性结节的独立预测因素,并绘制受试者工作特征(receiver operating characteristic,ROC)曲线分析ADC、K^(trans)独立诊断模型及ADC与K^(trans)联合诊断模型的诊断效能。结果良性结节组平均ADC值、K^(trans)值、K_(ep)值分别为(1.659±0.370)×10^(-3)mm^(2)/s、(0.427±0.214)min^(-1)、(0.966±0.225)min^(-1),恶性结节组平均ADC值、K^(trans)值、K_(ep)值分别为(1.182±0.195)×10^(-3)mm^(2)/s、(0.178±0.073)min^(-1)、(0.600±0.248)min^(-1)。良性结节组的ADC、K^(trans)、K_(ep)值均高于恶性结节组,差异均有统计学意义(P<0.001)。经过独立样本t检验及逐步logistic回归分析显示,ADC值和K^(trans)差异具有统计学意义(P<0.05),是鉴别甲状腺结节良恶性的独立预测因子。单独ADC值曲线下面积(area under the curve,AUC)为0.915、单独K^(trans)值AUC为0.827。ADC值与K^(trans)联合诊断模型AUC为0.973,较二者单独应用明显增高,联合诊断模型诊断效能最高。经DeLong检验,联合诊断模型与单独K^(trans)诊断差异存在统计学意义(P<0.05)。ADC值与K^(trans)联合诊断模型在鉴别甲状腺良恶性结节中敏感度为97.3%,较ADC、K^(trans)更高,特异度为84.6%,较ADC值更高。结论ADC值和K^(trans)是鉴别甲状腺良恶性结节的重要参数,两者联合诊断可提高临床诊断准确性,为术前诊断提供重要依据。

基于磁共振影像组学和语义特征对高级别胶质瘤和转移瘤的鉴别研究

目的本研究旨在结合传统MRI序列及增强检查,提取多模态高通量影像组学特征并联合语义特征,使用不同的机器学习分类器构建不同的模型并绘制列线图来鉴别高级别胶质瘤(high-grade glioma,HGG)和单发性脑转移瘤(solitary brain metastasis,SBM)。材料与方法本研究对101名患者的多参数MR图像进行了回顾性分析,由两位资深医师标定肿瘤感兴趣区,然后对每个序列分别提取影像组学特征后进行组合,共提取428组影像组学特征。为消除人为标定差异,进行组内相关系数一致性检验,并运用最大相关最小冗余算法选取最具相关性的特征,然后进一步通过最小绝对收缩和选择算子算法筛除冗余特征。本研究采用支持向量机、逻辑回归、随机森林及K近邻四种算法建立分类模型。结合放射科医生评估的七项语义特征,通过卡方检验和多因素分析去除差异无统计学意义的语义特征。然后结合组学特征建立综合模型并绘制列线图。最终,评价各模型的诊断能力,以确定最优分类器。结果HGG及SBM患者建立的影像组学模型中LR的受试者工作特征曲线下面积(area under the curve,AUC)值最高,训练集与测试集分别为0.90和0.90。语义特征建立的模型中随机森林模型性能最好,训练集和测试集AUC分别为0.82和0.87。语义特征联合影像组学评分后采用逻辑回归建立的模型性能最好,训练集和测试集AUC分别为0.91和0.92。结论本研究使用影像组学机器学习分类器并联合其他图像语义特征绘制列线图对HGG及SBM进行鉴别,这是一种非侵入性方法,具有较好的准确性,为临床决策和实践提供了较大的帮助。

多参数磁共振成像联合LI-RADS分级标准对肝硬化再生结节与小肝癌的诊断价值及临床意义

目的探讨多参数磁共振成像(Mp-MRI)联合肝脏影像报告和数据管理系统(LI-RADS)分级标准对肝硬化再生结节与小肝癌(SHCC)的诊断价值及临床意义。方法选取2019年3月至2023年3月我院直径≤3 cm的肝脏结节患者86例(132个结节),根据手术病理结果将肝硬化再生结节38例(54个结节)记为良性组,SHCC 48例(78个结节)记为恶性组。比较2组LI-RADS分级和Mp-MRI参数[增强率(ER)、平均强化时间(MET)、最大上升斜率(MSI)、最大下降斜率(MSD)、表观扩散系数(ADC)、脂肪分数(FF)],分析其诊断价值。结果经LI-RADS分级标准诊断,132个结节中共检出阳性76个,阴性56个,其中假阳性10个,假阴性12个;恶性组ER、MET、MSI、ADC低于良性组,FF、MSD高于良性组(P<0.05);受试者操作特征(ROC)曲线分析结果显示,Mp-MRI参数联合LI-RADS分级标准诊断肝硬化再生结节与SHCC的曲线下面积(AUC)为0.946(95%CI:0.892~0.977),约登指数为0.811,灵敏度为88.46%,特异度为92.59%,优于各Mp-MRI参数及LI-RADS分级单独诊断;恶性组不同病理分级结节LI-RADS分级比较,差异有统计学意义(P<0.05);ER、MET、MSI、ADC在高分化结节中最高,中分化结节次之,低分化结节最低,FF、MSD在低分化结节最高,中分化结节次之,高分化结节最低(P<0.05);Spearman相关性分析结果显示,LI-RADS分级、ER、MET、MSI、ADC与SHCC病理分级呈正相关,FF、MSD与SHCC病理分级呈负相关(P<0.05)。结论Mp-MRI参数联合LI-RADS分级标准诊断肝硬化再生结节与SHCC的价值可靠,且能为临床评估SHCC病理分级提供参考依据。