Is it a normal phenomenon for pediatric patients to have brain leptomeningeal contrast enhancement on 3-tesla magnetic resonance imaging?

Determining whether sevoflurane sedation in children leads to“pseudo”prominent leptomeningeal contrast enhancement(pLMCE)on 3 Tesla magnetic resonance imaging will help reduce overdiagnosis by radiologists and clarify the pathophysiological changes of pLMCE.

Pre-operative enhanced magnetic resonance imaging combined with clinical features predict early recurrence of hepatocellular carcinoma after radical resection

BACKGROUND Indentifying predictive factors for postoperative recurrence of hepatocellular carcinoma(HCC)has great significance for patient prognosis.AIM To explore the value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid(Gd-EOB-DTPA)enhanced magnetic resonance imaging(MRI)combined with clinical features in predicting early recurrence of HCC after resection.METHODS A total of 161 patients with pathologically confirmed HCC were enrolled.The patients were divided into early recurrence and non-early recurrence group based on the follow-up results.The clinical,laboratory,pathological results and Gd-EOB-DTPA enhanced MRI imaging features were analyzed.RESULTS Of 161 patients,73 had early recurrence and 88 were had non-early recurrence.Univariate analysis showed that patient age,gender,serum alpha-fetoprotein level,the Barcelona Clinic Liver Cancer stage,China liver cancer(CNLC)stage,microvascular invasion(MVI),pathological satellite focus,tumor size,tumor number,tumor boundary,tumor capsule,intratumoral necrosis,portal vein tumor thrombus,large vessel invasion,nonperipheral washout,peritumoral enhancement,hepatobiliary phase(HBP)/tumor signal intensity(SI)/peritumoral SI,HBP peritumoral low signal and peritumoral delay enhancement were significantly associated with early recurrence of HCC after operation.Multivariate logistic regression analysis showed that patient age,MVI,CNLC stage,tumor boundary and large vessel invasion were independent predictive factors.External data validation indicated that the area under the curve of the combined predictors was 0.861,suggesting that multivariate logistic regression was a reasonable predictive model for early recurrence of HCC.CONCLUSION Gd-EOB-DTPA enhanced MRI combined with clinical features would help predicting the early recurrence of HCC after operation.

Reactive lymphoid hyperplasia of the liver:Perinodular enhancement on contrast-enhanced computed tomography and magnetic resonance imaging

We report the case of a 69-year-old woman with reactive lymphoid hyperplasia(RLH) of the liver.She underwent partial hepatectomy under a preoperative diagnosis of hepatocellular carcinoma; however,histopathological analysis revealed RLH.The liver nodule showed the imaging feature of perinodular enhancement in the arterial dominant phase on contrast-enhanced computed tomography and magnetic resonance imaging,which could be a useful clue for identifying RLH in the liver.Histologically,the perinodular enhancement was compatible with prominent sinusoidal dilatation surrounding the liver nodule.

Gd-EOB-DTPA-enhanced magnetic resonance imaging for bile duct intraductal papillary mucinous neoplasms

AIM: To investigate gadolinium-ethoxybenzyldiethylenetriamine-pentaacetic acid(Gd-EOB-DTPA)-enhanced magnetic resonance imaging(MRI) of intraductal papillary mucinous neoplasms of the bile duct(IPMN-B). METHODS: The imaging findings of five cases of IPMN-B which were pathologically confirmed at our hospital between March 2012 and May 2013 were retrospectively analyzed. Three of these cases were diagnosed by duodenal endoscopy and biopsy pathology, and two cases were diagnosed by surgical pathology. All five patients underwent enhanced and non-enhanced computed tomography(CT), magnetic resonance cholangiopancreatography, and Gd-EOB-DTPA-enhanced MRI; one case underwent both Gd-EOB-DTPA-enhanced MRI and positron emission tomography-CT. The clinical data and imaging results for these cases were compared and are presented.RESULTS: Conventional imaging showed diffusedilatation of bile ducts and multiple intraductal polypoid and papillary neoplasms or serrated changes along the bile ducts. In two cases, Gd-EOB-DTPA-enhanced MRI revealed dilated biliary ducts and intraductal tumors, as well as filling defects caused by mucin in the dilated bile ducts in the hepatobiliary phase. GdEOB-DTPA-enhanced MRI in one case clearly showed a low-signal tumor in the hepatobiliary phase, similar to what was seen by positron emission tomographyCT. In two patients, routine inspection was unable to discern whether the lesions were inflammation or tumors. However, Gd-EOB-DTPA-enhanced MRI revealed a pattern of gradual enhancement during the hepatobiliary phase, and the signal intensity of the lesions was lower than the surrounding liver parenchyma, suggesting tissue inflammation in both cases, which were confirmed by surgical pathology. CONCLUSION: Gd-EOB-DTPA-enhanced MRI reveals the intraductal mucin component of IPMN-B in some cases and the extent of tumor infiltration beyond the bile ducts in invasive cases.

Comparison of endoscopic ultrasound, computed tomography and magnetic resonance imaging in assessment of detailed structures of pancreatic cystic neoplasms

AIM To evaluate the advantages of endoscopic ultrasound(EUS) in the assessment of detailed structures of pancreatic cystic neoplasms(PCNs) compared to computed tomography(CT) and magnetic resonance imaging(MRI).METHODS All patients with indeterminate PCNs underwent CT, MRI, and EUS. The detailed information, including size, number, the presence of a papilla/nodule, the presence of a septum, and the morphology of the pancreatic duct of PCNs were compared among the three imaging modalities. The size of each PCN was determined using the largest diameter measured. A cyst consisting of several small cysts was referred to as a motherdaughter cyst. Disagreement among the three imaging modalities regarding the total number of mother cysts resulted in the assumption that the correct number was the one in which the majority of imaging modalities indicated.RESULTS A total of 52 females and 16 males were evaluated. The median size of the cysts was 42.5 mm by EUS, 42.0 mm by CT and 38.0 mm by MRI; there was no significant difference in size as assessed among the three imaging techniques. The diagnostic sensitivity and ability of EUS to classify PCNs were 98.5%(67/68) and 92.6%(63/68), respectively. These percentages were higher than those of CT(73.1%, P < 0.001; 17.1%, P < 0.001) and MRI(81.3%, P = 0.001; 20.3%, P < 0.001). EUS was also able to better assess the number of daughter cysts in mother cysts than CT(P = 0.003); however, there was no significant difference between EUS and MRI in assessing mother-daughter cysts(P = 0.254). The papilla/nodule detection rate by EUS was 35.3%(24/68), much higher than those by CT(5.8%, 3/52) and MRI(6.3%, 4/64). The detection rate of the septum by EUS was 60.3%(41/68), which was higher than those by CT(34.6%, 18/52) and by MRI(46.9%, 30/64); the difference between EUS and CT was significant(P = 0.02). The rate of visualizing the pancreatic duct using EUS was 100%, whereas using CT and MRI it was less than 10%.CONCLUSION EUS helps visualize the detailed structures of PCNs and has many advantages over CT and MRI. EUS is valuable in the diagnosis and assessment of PCNs.

MAGNETIC RESONANCE IMAGING CHARACTERISTICS AND SURGICAL RESULTS OF ADRENOCORTICOTROPIN-SECRETING PITUITARY ADENOMAS

Objective To evaluate magnetic resonance imaging （MRI） characteristics and surgical results of adrenocorticotropin （ACTH） -secreting pituitary adenomas. Methods MRI characteristics and relationship between MRI positive rate and surgical results of 266 patients with pathologically confn＇med Cushing＇s disease were analyzed retrospectively. All patients underwent thin-section sagittal and coronal scans of the pituitary gland before and after administration of gadolinium-diethylene triamine pentaacetic acid （Gd-DTPA） on a 1. 5 Tesla MR/scanner, and dynamic enhanced MR/was performed in 39 patients. All patients underwent transsphenoidal adenomectomy. Endocrinological examinations and assessments were performed. Results Preoperative MR/revealed normal results in 41 （ 15.4% ） cases, microadenoma in 179 （67. 3% ）, macroadenoma in 42 （ 15.8% ）, and huge adenoma in 4 （ 1.5% ）. Pituitary apoplexy was found in 13 （4.9%） cases. Positive rate of ACTH-secreting adenomas was 84.6% （225/266） on MR/scans, and that of small microadenomas was 87.2% （34/39） on dynamic enhanced MRI scans. Preoperative endocrinological tests of 199 cases supported the diagnosis of typical Cushing＇s disease, while the other 67 cases had atypical endocrinological results. The endocrinological cure rate, remission rate, and inefficacy rate were 85.7%, 7.9%, and 6. 4%, respectively. There was no difference in the initial endocrinological cure rate between the patients with positive and normal MRI results （90% vs. 87. 8%, P =0. 904）. Conclusions Enhanced coronal pituitary MR/ is helpful for preoperative localization of ACTH-secreting pituitary microadenoma. Dynamic enhanced MR/may improve detection rate of microadenoma. There is no marked difference in the surgical results for patients with preoperative MR/results indicating presence or absence of microadenoma.

A modified method for locating parapharyngeal space neoplasms on magnetic resonance images: implications for differential diagnosis

The parapharyngeal space(PPS) is an inverted pyramid-shaped deep space in the head and neck region, and a variety of tumors, such as salivary gland tumors, neurogenic tumors, nasopharyngeal carcinomas with parapharyngeal invasion, and lymphomas, can be found in this space. The differential diagnosis of PPS tumors remains challenging for radiologists. This study aimed to develop and test a modified method for locating PPS tumors on magnetic resonance(MR) images to improve preoperative differential diagnosis. The new protocol divided the PPS into three compartments: a prestyloid compartment, the carotid sheath, and the areas outside the carotid sheath. PPS tumors were located in these compartments according to the displacements of the tensor veli palatini muscle and the styloid process, with or without blood vessel separations and medial pterygoid invasion. This protocol, as well as a more conventional protocol that is based on displacements of the internal carotid artery(ICA), was used to assess MR images captured from a series of 58 PPS tumors. The consequent distributions of PPS tumor locations determined by both methods were compared. Of all 58 tumors, our new method determined that 57 could be assigned to precise PPS compartments. Nearly all(13/14; 93%) tumors that were located in the pre-styloid compartment were salivary gland tumors. All 15 tumors within the carotid sheath were neurogenic tumors. The vast majority(18/20; 90%) of trans-spatial lesions were malignancies. However, according to the ICA-based method, 28 tumors were located in the pre-styloid compartment, and 24 were located in the post-styloid compartment, leaving 6 tumors that were difficult to locate. Lesions located in both the pre-styloid and the post-styloid compartments comprised various types of tumors. Compared with the conventional ICA-based method, our new method can help radiologists to narrow the differential diagnosis of PPS tumors to specific compartments.

Role of abdominal ultrasound for the surveillance follow-up of pancreatic cystic neoplasms: a cost-effective safe alternative to the routine use of magnetic resonance imaging

BACKGROUND Patients with pancreatic cystic neoplasms(PCN), without surgical indication at the time of diagnosis according to current guidelines, require lifetime imagebased surveillance follow-up. In these patients, the current European evidencedbased guidelines advise magnetic resonance imaging(MRI) scanning every 6 mo in the first year, then annually for the next five years, without reference to any role for trans-abdominal ultrasound(US). In this study, we report on our clinical experience of a follow-up strategy of image-based surveillance with US, and restricted use of MRI every two years and for urgent evaluation whenever suspicious changes are detected by US.AIM To report the results and cost-efficacy of a US-based surveillance follow-up for known PCNs, with restricted use of MRI.METHODS We retrospectively evaluated the records of all the patients treated in our institution with non-surgical PCN who received follow-up abdominal US and restricted MRI from the time of diagnosis, between January 2012 and January 2017. After US diagnosis and MRI confirmation, all patients underwent US surveillance every 6 mo for the first year, and then annually. A MRI scan was routinely performed every 2 years, or at any stage for all suspicious US findings.In this communication, we reported the clinical results of this alternative followup, and the results of a comparative cost-analysis between our surveillance protocol(abdominal US and restricted MRI) and the same patient cohort that has been followed-up in strict accordance with the European guidelines recommended for an exclusive MRI-based surveillance protocol.RESULTS In the 5-year period, 200 patients entered the prescribed US-restricted MRI surveillance follow-up. Mean follow-up period was 25.1 ± 18.2 mo. Surgery was required in two patients(1%) because of the appearance of suspicious features at imaging(with complete concordance between the US scan and the on-demand MRI). During the follow-up, US revealed changes in PCN appearance in 28 patients(14%). These comprised main pancreatic duct dilatation(n = 1), increased size of the main cyst(n = 14) and increased number of PNC(n = 13). In all of these patients, MRI confirmed US findings, without adding more information.The bi-annual MRI identified evolution of the lesions not identified by US in only11 patients with intraductal papillary mucinous neoplasms(5.5%), largely consisting of an increased number of very small PCN(P = 0.14). The overall mean cost of surveillance, based on a theoretical use of the European evidenced-based exclusive MRI surveillance in the same group of patients, would have been 1158.9± 798.6 € per patient, in contrast with a significantly lower cost of 366.4 ± 348.7 €(P < 0.0001) incurred by the US-restricted MRI surveillance used at our institution.CONCLUSION In patients with non-surgical PCN at the time of diagnosis, US surveillance could be a safe complementary approach to MRI, delaying and reducing the numbers of second level examinations and therefore reducing the costs.

Does sevoflurane sedation in pediatric patients lead to“pseudo”leptomeningeal enhancement in the brain on 3 Tesla magnetic resonance imaging?

BACKGROUND Prominent leptomeningeal contrast enhancement(LMCE)in the brain is observed in some pediatric patients during sedation for imaging.However,based on clinical history and cerebrospinal fluid analysis,the patients are not acutely ill and do not exhibit meningeal signs.Our study determined whether sevoflurane inhalation in pediatric patients led to this pattern of‘pseudo’LMCE(pLMCE)on 3 Tesla magnetic resonance imaging(MRI).AIM To highlight the significance of pLMCE in pediatric patients undergoing enhanced brain MRI under sedation to avoid misinterpretation in reports.METHODS A retrospective cross-sectional evaluation of pediatric patients between 0-8 years of age was conducted.The patients underwent enhanced brain MRI under inhaled sevoflurane.The LMCE grade was determined by two radiologists,and interobserver variability of the grade was calculated using Cohen’s kappa.The LMCE grade was correlated with duration of sedation,age and weight using the Spearman rho rank correlation.RESULTS A total of 63 patients were included.Fourteen(22.2%)cases showed mild LMCE,48(76.1%)cases showed moderate LMCE,and 1 case(1.6%)showed severe LMCE.We found substantial agreement between the two radiologists in detection of pLMCE on post-contrast T1 imaging(kappa value=0.61;P<0.001).Additionally,we found statistically significant inverse and moderate correlations between patient weight and age.There was no correlation between duration of sedation and pLMCE.CONCLUSION pLMCE is relatively common on post-contrast spin echo T1-weighted MRI of pediatric patients sedated by sevoflurane due to their fragile and immature vasculature.It should not be misinterpreted for meningeal pathology.Knowing pertinent clinical history of the child is an essential prerequisite to avoid radiological overcalling and the subsequent burden of additional investigations.

Magnetic resonance cholangiopancreatography image enhancement for automatic disease detection

AIM:To sufficiently improve magnetic resonance cholangiopancreatography(MRCP) quality to enable reliable computer-aided diagnosis(CAD).METHODS:A set of image enhancement strategies that included filters(i.e.Gaussian,median,Wiener and Perona-Malik),wavelets(i.e.contourlet,ridgelet and a non-orthogonal noise compensation implementation),graph-cut approaches using lazy-snapping and Phase Unwrapping MAxflow,and binary thresholding using a fixed threshold and dynamic thresholding via histogram analysis were implemented to overcome the adverse characteristics of MRCP images such as acquisition noise,artifacts,partial volume effect and large inter-and intra-patient image intensity variations,all of which pose problems in application development.Subjective evaluation of several popular pre-processing techniques was undertaken to improve the quality of the 2D MRCP images and enhance the detection of the significant biliary structures within them,with the purpose of biliary disease detection.RESULTS:The results varied as expected since each algorithm capitalized on different characteristics of the images.For denoising,the Perona-Malik and contourlet approaches were found to be the most suitable.In terms of extraction of the significant biliary structures and removal of background,the thresholding approaches performed well.The interactive scheme performed the best,especially by using the strengths of the graphcut algorithm enhanced by user-friendly lazy-snapping for foreground and background marker selection.CONCLUSION:Tests show promising results for some techniques,but not others,as viable image enhancement modules for automatic CAD systems for biliary and liver diseases.

The accuracy of magnetic resonance imaging and ultrasound in evaluating the size of early-stage breast neoplasms

Objective Breast cancer is the most frequently diagnosed cancer in women. Accurate evaluation of the size and extent of the tumor is crucial in selecting a suitable surgical method for patients with breast cancer. Both overestimation and underestimation have important adverse effects on patient care. This study aimed to evaluate the accuracy of breast magnetic resonance imaging(MRI) and ultrasound(US) examination for measuring the size and extent of early-stage breast neoplasms.Methods The longest diameter of breast tumors in patients with T_(1–2)N_(0–1)M_0 invasive breast cancer preparing for breast-conserving surgery(BCS) was measured preoperatively by using both MRI and US and their accuracy was compared with that of postoperative pathologic examination. If the diameter difference was within 2 mm, it was considered to be consistent with pathologic examination.Results A total of 36 patients were imaged using both MRI and US. The mean longest diameter of the tumors on MRI, US, and postoperative pathologic examination was 20.86 mm ± 4.09 mm(range: 11–27 mm), 16.14 mm ± 4.91 mm(range: 6–26 mm), and 18.36 mm ± 3.88 mm(range: 9–24 mm). US examination underestimated the size of the tumor compared to that determined using pathologic examination(t = 3.49, P < 0.01), while MRI overestimated it(t =-6.35, P < 0.01). The linear correlation coefficients between the image measurements and pathologic tumor size were r = 0.826(P < 0.01) for MRI and r = 0.645(P < 0.01) for US. The rate of consistency of MRI and US compared to that with pathologic examination was 88.89% and 80.65%, respectively, and there was no statistically significant difference between them(χ~2 = 0.80, P > 0.05).Conclusion MRI and US are both effective methods to assess the size of breast tumors, and they maintain good consistency with pathologic examination. MRI has a better correlation with pathology. However, we should be careful about the risk of inaccurate size estimation.

Magnetic resonance imaging of portal vein invasion in hepatocellular carcinoma:A corroboration of 25 cases

AIMS Pre-operatively to assess tumor thrombus as- sociated with hepatocellular carcinoma in the portal vein. METHEDS Twenty-five patients diagnosed as hav- ing thrombus due to hepatocellular carcinoma were corroborated. MR imaging was perfomed with a 1.0T superconducting magnetic system. Both T1 and T2 weighed images and FLASH sequences were obtained in transverse plane. Additional FLASH images were ob- tained in coronal plane. RESULTS Thrombus in portal vein had a signal in- tensity similar to that of the main tumors. Intrinsic por- tal vein thrombus was in 16 patients. Six cases showed occlusive thrombus. Diffusely narrow portal branches were found in 3 patients. Portal venous thrombus showed an area of signal intensity which was replacing the normal flow void in the portal vein and showed a stumpy portal vein,irregular stenosis of portal vein and the formation of vascular net. CONCLUSION MRI was more sensitive and specific and a noninvasive method in detection of portal tumor thrombus used jointly with spin ech (SE) and gradient echo (GRE) techniques.

Quantitative assessment of hepatic fibrosis in chronic hepatitis B and C: T1 mapping on Gd-EOB-DTPA-enhanced liver magnetic resonance imaging

AIM To assess the accuracy of Look-Locker on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid(GdEOB-DTPA)-enhanced magnetic resonance imaging(MRI) for staging liver fibrosis in chronic hepatitis B/C(CHB/C).METHODS We prospectively included 109 patients with CHB or CHC who underwent a 3.0-Tesla MRI examination, including T1-weighted and Look-Locker sequences for T1 mapping. Hepatocyte fractions(He F) and relaxation time reduction rate(RE) were measured for staging liver fibrosis. A receiver operating characteristic analysis using the area under the receiver operating characteristic curve(AUC) was used to compare thediagnostic performance in predicting liver fibrosis between He F and RE.RESULTS A total of 73 patients had both pathological results and MRI information. The number of patients in each fibrosis stage was evaluated semiquantitatively according to the METAVIR scoring system: F0, n = 23(31.5%); F1, n = 19(26.0%); F2, n = 13(17.8%); F3, n = 6(8.2%), and F4, n = 12(16.4%). He F by EOB enhancement imaging was significantly correlated with fibrosis stage(r =-0.808, P < 0.05). AUC values for diagnosis of any(≥ F1), significant(≥ F2) or advanced(≥ F3) fibrosis, and cirrhosis(F4) using He F were 0.837(0.733-0.913), 0.890(0.795-0.951), 0.957(0.881-0.990), and 0.957(0.882-0.991), respectively. He F measurement was more accurate than use of RE in establishing liver fibrosis staging, suggesting that calculation of He F is a superior noninvasive liver fibrosis staging method.CONCLUSION A T1 mapping-based He F method is an efficient diagnostic tool for the staging of liver fibrosis.

In vivo tracking of human adipose-derived stem cells labeled with ferumoxytol in rats with middle cerebral artery occlusion by magnetic resonance imaging

Ferumoxytol, an iron replacement product, is a new type of superparamagnetic iron oxide ap- proved by the US Food and Drug Administration. Herein, we assessed the feasibility of tracking transplanted human adipose-derived stem cells labeled with ferumoxytol in middle cerebral artery occlusion-injured rats by 3.0 T MRI in vivo. 1 × 104 human adipose-derived stem cells labeled with ferumoxytol-heparin-protamine were transplanted into the brains of rats with middle cerebral artery occlusion. Neurologic impairment was scored at 1, 7, 14, and 28 days after transplantation. T2-weighted imaging and enhanced susceptibility-weighted angiography were used to observe transplanted cells. Results of imaging tests were compared with results of Prussian blue staining. The modified neurologic impairment scores were significantly lower in rats transplanted with cells at all time points except I day post-transplantation compared with rats without transplantation. Regions with hypointense signals on T2-weighted and enhanced susceptibility-weighted angiography images corresponded with areas stained by Prussian blue, suggesting the presence of superparamagnetic iron oxide particles within the engrafted cells. Enhanced susceptibility-weighted angiography image exhibited better sensitivity and contrast in tracing ferumoxytol-heparin-protamine-labeled human adipose-derived stem ceils compared with T2-weighted imaging in routine MRI.

Three-Tesla magnetic resonance elastography for hepatic fibrosis:Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imaging.

Diagnostic value of gadobenate dimeglumine-enhanced hepatocyte-phase magnetic resonance imaging in evaluating hepatic fibrosis and hepatitis

AIM To evaluate the diagnostic value of gadobenate dimeglumine(Gd-BOPTA)-enhanced hepatocyte-phase magnetic resonance imaging(MRI) in evaluating hepatic fibrosis and hepatitis.METHODS Hepatocyte-phase images of Gd-BOPTA-enhanced MRI were retrospectively evaluated in 76 patients with chronic liver disease. These patients were classified into five groups according to either the histopathological fibrosis stage(S0-S4) or the histopathological hepatitis grade(G0-G4). The relative enhancement ratio(RE) of the liver parenchyma in the T1-vibe sequence was calculated by measuring the signal intensity before(SI pre) and 90 min after(SI post) intravenous injection of Gd-BOPTA using the following formula: RE =(SI post-SI pre)/SI pre. One-way analysis of variance was used to compare the difference between the relative RE in the hepatocyte phase(REh) and the stage of hepatic fibrosis and the grade of hepatitis. Pearson's productmoment correlation analysis was used to evaluate the relationship between the REh and the levels of serologic liver functional parameters.RESULTS According to histopathological hepatic fibrosis stage, the 76 patients were classified into five groups: 16 in S0, 15 in S1, 21 in S2, 9 in S3, and 15 in S4 group. According to histopathological hepatitis grade, the 76 patients were also classified into five groups: 0 in G0, 44 in G1, 22 in G2, 8 in G3, and 2 in G3 group. With regard to the stage of hepatic fibrosis, REh showed significant differences between the S2 and S3 groups and between the S2 and S4 groups(P < 0.05), but no significant difference was observed between the other groups. With regard to the grade of hepatitis, REh showed significant differences between the G1 and G2 groups and between the G1 and G4 groups(P < 0.05), but no significant difference was observed between the other groups. Increased REh showed correlations with decreased serum levels of TB, ALT and AST(P < 0.05). CONCLUSION To some extent, measuring the REh using Gd-BOPTAenhanced MRI might be a noninvasive technique for assessing the stage of hepatic fibrosis. This method is able to differentiate no/mild hepatitis from advanced hepatitis. TB, ALT and AST levels can predict the degree of liver enhancement in the hepatocyte phase of Gd-BOPTA-enhanced MRI.

Combined molybdenum target X-ray and magnetic resonance imaging examinations improve breast cancer diagnostic efficacy

BACKGROUND Early-stage breast cancer patients often lack specific clinical manifestations,making diagnosis difficult.Molybdenum target X-ray and magnetic resonance imaging(MRI)examinations both have their own advantages.Thus,a combined examination methodology may improve early breast cancer diagnoses.AIM To explore the combined diagnostic efficacy of molybdenum target X-ray and MRI examinations in breast cancer.METHODS Patients diagnosed with breast cancer at our hospital from March 2019 to April 2021 were recruited,as were the same number of patients during the same period with benign breast tumors.Both groups underwent molybdenum target X-ray and MRI examinations,and diagnoses were given based on each exam.The single(i.e.,X-ray or MRI)and combined(i.e.,using both methods)diagnoses were counted,and the MRI-related examination parameters(e.g.,T-wave peak,peak and early enhancement rates,and apparent diffusion coefficient)were compared between the groups.RESULTS In total,63 breast cancer patients and 63 benign breast tumor patients were recruited.MRI detected 53 breast cancer cases and 61 benign breast tumor cases.Molybdenum target X-ray detected 50 breast cancer cases and 60 benign breast tumor cases.The combined methodology detected 61 breast cancer cases and 61 benign breast tumor cases.The sensitivity(96.83%)and accuracy(96.83%)of the combined methodology were higher than single-method MRI(84.13%and 90.48%,respectively)and molybdenum target X-ray(79.37%and 87.30%,respectively)(P<0.05).The combined methodology specificity(96.83%)did not differ from singlemethod MRI(96.83%)or molybdenum target X-ray(95.24%)(P>0.05).The Twave peak(169.43±32.05)and apparent diffusion coefficient(1.01±0.23)were lower in the breast cancer group than in the benign tumor group(228.86±46.51 and 1.41±0.35,respectively).However,the peak enhancement rate(1.08±0.24)and early enhancement rate(1.07±0.26)were significantly higher in the breast cancer group than in the benign tumor group(0.83±0.19 and 0.75±0.19,respectively)(P<0.05).CONCLUSION Combined molybdenum target X-ray and MRI examinations for diagnosing breast cancer improved the diagnostic sensitivity and accuracy,minimizing the missedand misdiagnoses risks and promoting timely treatment intervention.

Intraoperative perfusion magnetic resonance imaging: Cutting-edge improvement in neurosurgical procedures

The goal in brain tumor surgery is to remove the maxi-mum achievable amount of the tumor, preventing damage to "eloquent" brain regions as the amount of brain tumor resection is one of the prognostic factors for time to tumor progression and median survival. To achieve this goal, a variety of technical advances have been in-troduced, including an operating microscope in the late 1950 s, computer-assisted devices for surgical navigation and more recently, intraoperative imaging to incorporate and correct for brain shift during the resection of the lesion. However, surgically induced contrast enhancement along the rim of the resection cavity hampers interpretation of these intraoperatively acquired magnetic resonance images. To overcome this uncertainty, perfusion techniques [dynamic contrast enhanced magnetic resonance imaging(DCE-MRI), dynamic susceptibility contrast magnetic resonance imaging(DSC-MRI)] have been introduced that can differentiate residual tumor from surgically induced changes at the rim of the resec-tion cavity and thus overcome this remaining uncer-tainty of intraoperative MRI in high grade brain tumor resection.

Magnetic resonance imaging of the liver:New imaging strategies for evaluating focal liver lesions

The early detection of focal liver lesions,particularly those which are malignant,is of utmost importance.The resection of liver metastases of some malignancies(including colorectal cancer)has been shown to improve the survival of patients.Exact knowledge of the number,size,and regional distribution of liver metastases is essential to determine their resectability.Almost all focal liver lesions larger than 10 mm are demonstrated with current imaging techniques but the detection of smaller focal liver lesions is still relatively poor.One of the advantages of magnetic resonance imaging(MRI)of the liver is better soft tissue contrast(compared to other radiologic modalities),which allows better detection and characterization of the focal liver lesions in question.Developments in MRI hardware and software and the availability of novel MRI contrast agents have further improved the diagnostic yield of MRI in lesion detection and characterization.Although the primary modalities for liver imaging are ultrasound and computed tomography,recent studies have suggested that MRI is the most sensitive method for detecting small liver metastatic lesions,and MRI is now considered the pre-operative standard method for diagnosis.Two recent developments in MRI sequences for the upper abdomen comprise unenhanced diffusion-weighted imaging(DWI),and keyhole-based dynamic contrast-enhanced(DCE)MRI(4D THRIVE).DWI allows improved detection(b=10 s/mm2)of small(<10 mm)focal liver lesions in particular,and is useful as a road map sequence.Also,using higher b-values,the calculation of the apparent diffusion coefficient value,true diffusion coefficient,D,and the perfusion fraction,f,has been used for the characterization of focal liver lesions.DCE 4D THRIVE enables MRI of the liver with high temporal and spatial resolution and full liver coverage.4D THRIVE improves evaluation of focal liver lesions,providing multiple arterial and venous phases,and allows the calculation of perfusion parameters using pharmacokinetic models.4D THRIVE has potential benefits in terms of detection,characterization and staging of focal liver lesions and in monitoring therapy.

Role of dynamic perfusion magnetic resonance imaging in patients with local advanced rectal cancer

BACKGROUND The management of rectal cancer patients is mainly based on the use of the magnetic resonance imaging(MRI)technique as a diagnostic tool for both staging and restaging.After treatment,to date,the evaluation of complete response is based on the histopathology assessment by using different tumor regression grade(TRG)features(e.g.,Dworak or Mandard classifications).While from the radiological point of view,the main attention for the prediction of a complete response after chemotherapy treatment focuses on MRI and the potential role of diffusion-weighted images and perfusion imaging represented by dynamiccontrast enhanced MRI.The main aim is to find a reliable tool to predict tumor response in comparison to histopathologic findings.AIM To investigate the value of dynamic contrast-enhanced perfusion-MRI parameters in the evaluation of the healthy rectal wall and tumor response to chemo-radiation therapy in patients with local advanced rectal cancer with histopathologic correlation.METHODS Twenty-eight patients with biopsy-proven rectal adenocarcinoma who underwent a dynamic contrast-enhanced MR study performed on a 1.5 T MRI system(Achieva,Philips),before(MR1)and after chemoradiation therapy(MR2),were enrolled in this study.The protocol included T1 gadolinium enhanced THRIVE sequences acquired on axial planes.A dedicated workstation was used to generate color permeability maps.Region of interest was manually drawn on tumor tissue and normal rectal wall,hence the following parameters were calculated and statistically analyzed:Relative arterial enhancement(RAE),relative venous enhancement(RVE),relative late enhancement(RLE),maximum enhancement(ME),time to peak and area under the curve(AUC).Perfusion parameters were related to pathologic TRG(Mandard’s criteria;TRG1=complete regression,TRG5=no regression).RESULTS Ten tumors(36%)showed complete or subtotal regression(TRG1-2)at histology and classified as responders;18 tumors(64%)were classified as non-responders(TRG3-5).Perfusion MRI parameters were significantly higher in the tumor tissue than in the healthy tissue in MR1(P<0.05).At baseline(MR1),no significant difference in perfusion parameters was found between responders and nonresponders.After chemo-radiation therapy,at MR2,responders showed significantly(P<0.05)lower perfusion values[RAE(%)54±20;RVE(%)73±24;RLE(%):82±29;ME(%):904±429]compared to non-responders[RAE(%):129±45;RVE(%):154±39;RLE(%):164±35;ME(%):1714±427].Moreover,in responders group perfusion values decreased significantly at MR2[RAE(%):54±20;RVE(%):73±24;RLE(%):82±29;ME(%):904±429]compared to the corresponding perfusion values at MR1[RAE(%):115±21;RVE(%):119±21;RLE(%):111±74;ME(%):1060±325];(P<0.05).Concerning the time-intensity curves,the AUC at MR2 showed significant difference(P=0.03)between responders and non-responders[AUC(mm2×10-3)121±50 vs 258±86],with lower AUC values of the tumor tissue in responders compared to nonresponders.In non-responders,there were no significant differences between perfusion values at MR1 and MR2.CONCLUSION Dynamic contrast perfusion-MRI analysis represents a complementary diagnostic tool for identifying vascularity characteristics of tumor tissue in local advanced rectal cancer,useful in the assessment of treatment response.