Dynamic Enhancement Magnetic Resonance Imaging Research Articles

Sinistral Portal Hypertension in Acute Pancreatitis: A Magnetic Resonance Imaging Study.

The aim of the study was to study the prevalence and characteristics of sinistral portal hypertension (SPH) in acute pancreatitis (AP) and its correlation with the severity of AP. Retrospectively studied 633 patients with AP admitted to our institution and underwent magnetic resonance imaging (MRI). Diagnosis of SPH was based on clinical manifestations, laboratory tests, and MRI. The venous system and pancreatitis were evaluated on T1 weighted imaging, T2 weighted imaging, and dynamic-enhancement MRI. Data on patients' demographics, etiology, organ failure, MR severity index, and clinical outcomes were all collected. The SPH was detected in 21 patients (3.3%, 21/633). There was no statistical difference in organ failure between patients with SPH and without SPH (P > 0.05). The prevalence of SPH in males and females was 5.1% (17/336) versus 1.3% (4/297) (χ(2) = 6.775, P = 0.009), in edematous and necrotizing AP was 0.4% (2/510) versus 15.5% (19/123) (χ(2) = 65.413, P = 0.000), and in mild, moderate, and severe AP, based on MR severity index, were 0.6% (2/334) versus 2.9% (8/276) versus 47.8% (11/23) (χ(2) = 55.977, P = 0.000), respectively. The SPH rarely occurs in AP, and its risk is higher in males. Its presence is strongly associated with the local conditions of pancreatitis.

Application of quantitative imaging technique in the diagnosis of pancreatic cancer

Pancreatic cancer is a malignant tumor, and the clinical manifestations are not characteristic, so it is difficult to diagnose at an early stage, and it has a poor prognosis.Image technology has been widely used in clinical, with mature technology, and the application of image technology not only confined to the image display, but also has become a hot spot of research, including dynamic contrast enhancement magnetic resonance imaging (DCE-MRI), intravoxel incoherent motion (IVIM), CT perfusion imaging, which could analyze quantitatively the permeability and microvascular of lesions, to improve the sensitivity of diagnosis, and to assess quantitatively the effect of drugs, radiation and chemotherapy. Key words: Pancreatic neoplasms; Radiographic image interpretation, computer-assisted; Magnetic resonance imaging; Intravoxel Incoherent Motion (IVIM); Perfusion imaging; Review

Diagnosis and differential diagnosis between focal nodular hyperplasia with inflammatory hepatocellular adenoma on MRI

Objective To compare the MRI features of focal nodular hyperplasia (FNH) and inflammatory hepatocellular adenoma (I-HCA), with an aim to improve the diagnostic accuracy in the two lesions. Methods Patients who underwent dynamic-enhanced MRI with histopathologically confirmed FNHs (21 patients with 21 tumors) and I-HCAs (10 patients with 12 tumors) were included in this retrospective study. The clinical and the imaging features, including the T2-and T1-weighted, diffusion weighted images, and the dynamic enhanced imagings were analyzed. Results No significant difference was observed in the clinical data between the 2 groups of patients, except in the serum levels of C-reactive protein. The serum C-reactive protein levels were significantly elevated in I-HCA than in FNH. Significant differences between patients with FNHs and I-HCAs were also found in the morphologic findings and the signal intensities (including shape, centre scar, necrosis, signal intensity of T2WI and DWI, and lesion signal intensity compared to those of the liver in the portal venous phase and delayed phase). The differences in lesion to liver signal in FNH were significantly lower than those in I-HCA in the T2WI and the delayed phases. The area under the curve (AUC) for the 2 groups of patients were 0.843 and 0.743, respectively, with no significant difference between them. Conclusions The MRI appearances of atypical FNHs overlapped with I-HCA. MRI features of isointensity on T2WI and DWI, and isointensity to the liver in the delayed phase were valuable to differentiate FNHs from I-HCAs. Most I-HCAs showed moderate and marked high signal intensity on T2WI and DWI. These features, when combined with an elevated serum C-reaction protein, necrosis in the lesion and hyperintensity in the delayed phase, were valuable in differentiating I-HCAs from FNH. Key words: Focal nodular hyperplasia; Inflammatory hepatocellular adenoma; Magnetic resonance imaging (MRI); Comparative study

Clinical utility of dynamic-enhanced MRI in salivary gland tumors: retrospective study and literature review.

To improve the diagnoses of the salivary gland tumors, a dynamic-enhanced MRI (dMRI) was investigated. We conducted a retrospective chart review of 93 cases of salivary gland tumors. The histological diagnoses were obtained from all patients using a surgical specimen and/or an open biopsy specimen. The dMRI as well as fine-needle aspiration cytology (FNAC) and intraoperative frozen section (IFS) were analyzed. This study focused on the time-intensity curve (TIC) after injection, peak time (Tpeak), washout ratio (WR) as well as the gradient of enhancement and washout profile. The histological diagnoses included pleomorphic adenoma (PMA) in 53 cases, the Warthin tumors (WT) in 14 cases and malignant tumors (MT) in 26 cases. Incorrect diagnosis rate of FNAC and IFS were 5.2 and 8.3%, respectively. The TIC revealed differences among the three types of tumors. Tpeak as well as WR also revealed significant differences (p < 0.001). Tpeak were lower in order of WT, MT, PMA, respectively. WR of TICs at 30, 45 and 105s after Tpeak were higher in order of WT, MT, PMA, respectively (p < 0.001). The gradient of increment and washout in the TIC curve was also an important parameter to distinguish the three types of tumors. In MT, the rapid enhancement pattern was found in high or intermediate histological grade tumors, whereas the slow enhancement pattern was exhibited in low grade tumors. Our findings indicate that using Tpeak and WR, it is possible to distinguish between WT, PMA and MT. Additionally, a rapid enhancement pattern may be a potential marker for these tumors.

MRI features of adult metanephric adenoma

Objective To investigate MRI features of metanephric adenoma(MA). Methods The retrospective analysis was performed on 6 adult patients that were scanned by regular, DWI and dynamic-enhancement MRI two weeks before surgery and diagnosed with MA pathologically after surgery. MRI features of lesions were observed. The signal intensities of lesions and contralateral normal renal cortex and medulla were respectively measured in plain scan, cortex, parenchyma and delayed phase. The enhancement magnitudes were calculated and the ADC values of lesions were measured. The differences of the signal intensity and enhancement magnitude were assessed by paired-sample t test among renal cotex, medulla and lesions. Results All lesions in MA were single and solid masses. Four cases occurred in the right kidney and two cases in the left kidney. The maximum diameters of the lesions ranged from 21 to 79 mm and the mean value was(41±20)mm. Five cases were round or oval, while one case was irregular. The signal intensity in five cases was slightly lower in T2WI than the renal parenchyma, while one case was slightly higher than the renal parenchyma. The hyperintentsity of DWI and hypointensity of ADC were seen in all cases. The mean ADC value was(0.759±0.211)×10-3mm2/s. Hemorrhage were seen in two cases. Necrosis was present in one case and the capsules were seen in two cases. No scar, fat and swollen lymph nodes was seen in all cases. There was no statistical significance of the signal intensity between lesions measure in the plain scan and normal renal parenchyma(P>0.05). After adminstrating contrast materials, all lesions shown persistently mild to moderate enhancement. The siganl intensities of lesions measured in three phases after enhancement were signifcantly lower than those of the renal cortex(P 0.05). But the signal intensities of leisons in delayed phases were significantly lower than thoseof renal medulla(P<0.05). Except from the difference of enhanced magnitude in cortex phase between lesions and normal medulla, significant differences were present between leisons and normal renal parenchyma(P<0.05). Conclusion MRI manifestations of MA show certain distinction, including, dominantly solid lesions, relatively lower signal intensity of lesions than that of renal cortex, slowly persistent enhancement, high signal on DWI and low signal on ADC. Key words: Kidney neoplasms; Magnetic resonance imaging

Radiomic analysis of DCE-MRI for prediction of response to neoadjuvant chemotherapy in breast cancer patients

ObjectivesTo enhance the accurate prediction of the response to neoadjuvant chemotherapy (NAC) in breast cancer patients by using a quantitative analysis of dynamic enhancement magnetic resonance imaging (DCE-MRI). Materials and methodsA dataset of 57 cancer patients with breast DCE-MR images acquired before NAC was used. Among them, 47 patients were Responders, and 10 patients were non-Responders based on the RECIST criteria. The breast regions were segmented on the MR images, and a total of 158 radiomic features were computed to represent the morphologic, dynamic, and the texture of the tumors as well as the background parenchymal features. The optimal subset of features was selected using evolutionary based Wrapper Subset Evaluator. The classifier was trained and tested using a leave-one-out cross-validation (LOOCV) method to classify Responder and non-Responder cases. The area under a receiver operating characteristic curve (AUC) was computed to assess the classifier performance. An additional independent dataset with 46 patients was also included to validate the results. ResultsThe evolutionary algorithm (EA)-based method identified optimal subsets comprising 12 image features that were fit for classification for the main cohort. Following the same feature selection procedure, the independent validation dataset produced 11 image features, 7 of which were identical to those from the main cohort. The classifier based on the features yield a LOOCV AUC of 0.910 and 0.874 for the main and the reproducibility study cohort, respectively. If the optimal features in the main cohort were utilized to test performance on the reproducibility cohort, the classifier generated an AUC of 0.713. While the features developed in the reproducibility cohort were applied to test the main cohort, the classifier achieved an AUC of 0.683. The AUC of the averaged receiver operating characteristic (ROC) curve for the two data cohort was 0.703. ConclusionsThis study demonstrated that quantitative analyses of radiomic features from pretreatment breast DCE-MRI data could be used as valuable image markers that are associated with tumor response to NAC.

Correlation between histogram analysis of dynamic contrast enhanced MRI and diffusion weighted imaging intravoxel incoherent motion quantitative parameters and Gleason score of prostate cancer

Objective To investigate the value and diagnostic efficiency of the quantitative dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) and intravoxel incoherent motion (IVIM) parameters using three dimention (3D)-histogram analysis for discriminating the Gleason score (GS) of prostate cancer. Methods A total of 53 patients pathologically confirmed as prostate cancer by systemic prostate biopsy who had routine, DCE and DWI-MRI scans were retrospectively analyzed. There were 15 cases for low-risk and 38 cases for intermediate/high-risk prostate cancer. The 3D ROI of all lesions based on T2WI was achieved by image registration to get the quantitative parameters of DCE-MRI and DWI-IVIM. The parameters of DCE-MRI contains: transfer constant (Ktrans), rate constant (Kep) and extracellular-extravascular volume fraction (Ve).The DWI-IVIM related quantitative parameters were ADC, diffusion coefficient (D), diffusion coefficient related to perfusion (D*) and perfusion fraction (f). Then the histogram analysis of these quantitative parameters was performed to get the mean, median, 25th percentile, 75th percentile, Skewness and Kurtosis. Using the Spearman rank correlation analysis to evaluate the correlation of these parameters and GS of prostate cancer. The diagnostic performance of these quantitative histogram parameters related to the GS in identifying low-risk and intermediate/high-risk of prostate cancer was carried by ROC. Results The Kep and Ktrans (mean, median, 25th, 75th) of DCE-MRI were positively correlated with GS (r value was 0.346 to 0.696, P<0.05). The ADC (mean, median, 25th, 75th), D (mean, median, 25th, 75th, Skewness, Kurtosis) and D*(25th) of DWI-IVIM were correlated with GS (r value was -0.544 to 0.428, P<0.05). The DCE-MRI quantitative parameters Kep (25th) had the highest area under curve (AUC, 0.961); The ADC (median) and D (25th) had higher AUC (0.832, 0.888) in the quantitative parameters of DWI-IVIM, the difference between Kep(25th) and ADC (median) was statistically significant (Z value was 2.212, P value was 0.027). The difference of AUC between Kep (25th) and D (25th), D (25th) and ADC (median) was not statistically significant (Z values were 1.027 and 1.398, P values were 0.162 and 0.304, respectively). Conclusion DCE and IVIM quantitative parameters (Kep, Ktrans, ADC, D) histogram analysis results are correlated with GS, and can be used for distinguishing low-risk from intermediate/high-risk prostate cancer. Key words: Prostate neoplasms; Magnetic resonance imaging; Comparative study

Assessment on T1 mapping values using gadoxetic acid-enhanced MRI examination in comparison with organic anion transporters and multi-drug resistance proteins values on the hepatocytes on colorectal liver metastases

Objective To evaluate the relationship between the T1 relaxation times using gadoxetic acid-enhanced MRI with the organic anion transporter (OATP) and multi-drug resistance protein (MRP) values on colorectal liver metastasis and around normal liver parenchyma. Methods The perspective study included in fifteen patients with liver metastasis from colorectal cancer, who were confirmed colorectal cancer by colonoscopy, liver metastasis by CT scanning and would be underwent liver metastasis surgery. The lesion on the 15 patients was all single. The patients were performed plain scanning, diffusion weighted imaging and dynamic enhancement MRI examination using gadoxetic acid. Besides, for T1 mapping, a dual flip angle three-dimensional gradient echo sequence was performed before and at 20 minutes after gadoxetic acid administration. The reduction rate of T1 relaxation time (ΔT) (before and after gadoxetic-acid administration) of colorectal liver metastasis and around normal liver parenchyma was calculated. The specimens of hepatic metastases and around normal liver parenchyma were obtained during the colorectal liver metastasis operation. After that, they were analyzed by Western-blot and the values on OATP1, OATP8 and MRP2, MRP3 were recorded. The values on OATP1, OATP8 and MRP2, MRP3 and ΔT on hepatic metastases and around normal liver parenchyma were compared with t analysis. The correlation between the sum of the values (hepatic metastases adding around normal liver parenchyma) on OATP1, OATP8, MRP2, MRP3 with T1 relaxation times were calculated by Spearman. Results The scanning images on colorectal liver metastasis using gadoxetic acid MRI examination were as follows: relatively low signal intensity on T1WI; relatively higher signal intensity on T2WI; showing surrounding moderate enhancement on arterial phase and low signal intensity on portal venous phase, delay phase and hepatobililary phase. The values on OATP1, OATP8, MRP2, MRP3 and ΔT on the hepatic metastases were(0.21±0.09), (0.34±0.21), (0.41±0.22), (0.26±0.14)ng/ml and (33±9)%, respectively. The values on OATP1, OATP8, MRP2, MRP3 and ΔT around normal liver parenchyma were (0.46±0.24),(0.67±0.35), (0.22±0.13), (0.13±0.06) ng/ml and(68±9)%(t values were 36.37,58.89,24.56,22.52 and 57.16;P<0.05). The values on patients on OATP1,OATP8,MRP2 and MRP3 [(0.67±0.31),(1.00±0.37), (0.63±0.23), (0.40±0.13)ng/ml, respectively] showed relationship with the values on patients on ΔT(51±9)% (r values were 0.491, 0.432, -0.414 and -0.371;P values were 0.006, 0.017, 0.023 and 0.040). Conclusion The sum of the values (the hepatic metastases adding around normal liver parenchyma) on OATP1, OATP8, MRP2 and MRP3 showed correlation with the sum of values on the ΔT using gadoxetic acid-enhanced MRI examination, which explained relationship with the quantity of gadoxetic acid absorbed by hepatocyte and the T1 relaxation time on molecular level. Key words: Liver neoplasms; Contrast media; Magnetic resonance imaging

Imaging of the wrist

• MR or CT is advocated in the assessment of radiographically occult fractures. • The intrinsic ligaments of the wrist are better visualized at 3.0-T MRI than at 1.5-T MRI; however, MR or multidetector CT arthrography is the most sensitive at detecting intrinsic ligament and triangular fibrocartilage complex (TFCC) tears. • MR is more sensitive at detecting scapholunate ligament tears than lunotriquetral ligament tears. • TFCC tears can be divided into traumatic or degenerative tears, the latter being related to ulnar impaction syndrome. • Chronic wrist pain as a result of trauma may be secondary to scaphoid avascular necrosis, malunion, non-union, scapholunate advanced collapse and scaphoid non-union advanced collapse wrist or chronic regional pain syndrome. • Specific ulnar-sided wrist pain has its own unique causes that are optimally imaged with MR. • Doppler ultrasound and dynamic-enhanced MRI are the most sensitive imaging tools for diagnosing and monitoring synovitis in inflammatory arthropathies. • Most masses in the wrist and hand are benign and have typical imaging appearances. This article details the current imaging modalities utilized in the assessment of wrist pathology, with particular emphasis on recent developments and difficult areas. A stepwise approach for the assessment of wrist pathology in the context of clinical presentation will be discussed. The radiologist's role in the evaluation of wrist pain continues to evolve with the growing development of new techniques in order to evaluate with greater sensitivity the disorders affecting the complex joint and ligamentous structures of the wrist. The imaging strategy for wrist pathology begins with radiographs, with the use of further imaging such as ultrasound, CT, MRI and arthrography techniques if the diagnosis remains unclear.

Features of magnetic resonance imaging of pancreatic endocrine tumors

Pancreatic endocrine tumors (PETs) are very rare and are divided into functional and nonfunctional tumors.Their clinical manifestations vary,and imaging diagnosis easily led to missing diagnosis and misdiagnosis for PETs.With the development of MRI technology,especially application of fat suppression techniques,diffusion weighted imaging (DWI) and dynamic enhanced magnetic resonance imaging (DEMRI) are of great value on imaging diagnosis and differential diagnosis for PETs.The clinical data of 13 patients with PETs who were admitted to the Central Hospital of Enshi Autonomous Prefecture from June 2007 to December 2011 were retrospectively analyzed,and their MRI imaging features were studied.The diagnostic values of MRI,especially DWI and DEMRI for PETs were investigated. Key words: Pancreatic neoplasms; Magnetic resonance imaging; Diffusion weighted imaging; Dynamic enhancement imaging

Surgically proved visually isoattenuating pancreatic adenocarcinoma undetected in both dynamic CT and MRI. Was blind pancreaticoduodenectomy justified?

INTRODUCTIONVisually isoattenuating pancreatic adenocarcinoma is defined as a mass not directly visible on CT and recognizable only by secondary imaging signs. The frequency of isoattenuating pancreatic adenocarcinomas at dynamic-enhanced CT has been reported to range from 5.4% to 14%. Furthermore, 80% of the visually isoattenuating pancreatic adenocarcinomas are detectable in dynamic-enhanced MRI. Consequently, a pancreatic adenocarcinoma undetected in both the above imaging studies is an exceptionally rare event. PRESENTATION OF CASEThe present report describes a case of a histologically proved 3.5cm pancreatic adenocarcinoma undetected in both dynamic-enhanced CT and MRI. The patient presented with progressive jaundice over the preceding 20 days. Initial abdominal CT showed a dilated pancreatic and common bile duct without demonstration of a lesion responsible for the clinical and imaging findings. Additional diagnostic work-up with dynamic CT and dynamic MRI failed to reveal a definitive mass. ERCP revealed an irregular interruption of the pancreatic and distal common bile duct with upstream dilation. Blind radical pancreaticoduodenectomy was performed. Histologic examination showed a pT3pN1MO pancreatic ductal adenocarcinoma of the head/neck. DISCUSSIONIsoattenuating pancreatic adenocarcinoma patients represent a small but meaningful subset of patients with pancreatic cancer, as they have better survival. The more favorable postsurgical survival makes it even more imperative to correctly diagnose their cases at early stages by obtaining further diagnostic work-up with dynamic pancreatic CT, dynamic MRI and endoscopic ultrasound. CONCLUSIONWhen the above studies fail to unmask the lesion, blind pancreaticoduodenectomy should be based on strong clinical suspicion and secondary imaging findings.

Nonmalignant Breast Lesions: ADCs of Benign and High-Risk Subtypes Assessed as False-Positive at Dynamic Enhanced MR Imaging

To evaluate the diffusion-weighted (DW) imaging characteristics of nonmalignant lesion subtypes assessed as false-positive findings at conventional breast magnetic resonance (MR) imaging. This HIPAA-compliant retrospective study had institutional review board approval, and the need for informed patient consent was waived. Lesions assessed as Breast Imaging Reporting and Data System category 4 or 5 at clinical dynamic contrast material-enhanced MR imaging that subsequently proved nonmalignant at biopsy were retrospectively reviewed. One hundred seventy-five nonmalignant breast lesions in 165 women were evaluated. Apparent diffusion coefficients (ADCs) from DW imaging (b = 0, 600 sec/mm(2)) were calculated for each lesion and were compared between subtypes and with an ADC threshold of 1.81 × 10(-3) mm(2)/sec (determined in a prior study to achieve 100% sensitivity). Eighty-one (46%) lesions exhibited ADCs greater than the predetermined threshold. The most prevalent lesion subtypes with mean ADCs above the threshold were fibroadenoma ([1.94 ± 0.38 {standard deviation}] × 10(-3) mm(2)/sec; n = 30), focal fibrosis ([1.84 ± 0.48] × 10(-3) mm(2)/sec; n = 19), normal tissue ([1.81 ± 0.47] × 10(-3) mm(2)/sec; n = 13), apocrine metaplasia ([2.01 ± 0.38] × 10(-3) mm(2)/sec; n = 13), usual ductal hyperplasia ([1.83 ± 0.49] × 10(-3) mm(2)/sec; n = 12), and inflammation ([1.95 ± 0.46] × 10(-3) mm(2)/sec; n = 10). Atypical ductal hyperplasia ([1.48 ± 0.36] × 10(-3) mm(2)/sec; n = 23) was the most common lesion subtype with ADC below the threshold. Lymph nodes exhibited the lowest mean ADC of all nonmalignant lesions ([1.28 ± 0.23] × 10(-3) mm(2)/sec; n = 4). High-risk lesions (atypical ductal hyperplasia and lobular neoplasia) showed significantly lower ADCs than other benign lesions (P < .0001) and were the most common lesions with ADCs below the threshold. Assessing ADC along with dynamic contrast-enhanced MR imaging features may decrease the number of avoidable false-positive findings at breast MR imaging and reduce the number of preventable biopsies. The ability of DW imaging to help differentiate high-risk lesions requiring additional work-up from other nonmalignant subtypes may further improve patient care. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112672/-/DC1.

Quantitative characterization of bone marrow edema pattern in rheumatoid arthritis using 3 tesla MRI

To develop imaging techniques that provide quantitative characterization of bone marrow edema pattern (BME) in wrist joints of patients with rheumatoid arthritis (RA), including volume, signal intensity changes, and perfusion properties. Fourteen RA patients and three controls were scanned using 3 Tesla MR. BME was semi-automatically segmented in water images obtained from iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) sequences. BME perfusion parameters (enhancement and slope) were evaluated using three-dimensional (3D) dynamic enhanced MRI (DCE-MRI). Experimental reproducibility, inter- and intra-observer reproducibility of BME quantification were evaluated using root mean square coefficients of variation (RMS-CV) and intraclass correlation (ICC). The RMS-CV for BME volume quantification with repeated scans were 6.9%. The inter-observer ICC was 0.993 and RMS CV was 5.2%. The intra-observer ICC was 0.998 and RMS CV was 2.3%. Both maximum enhancement and slope during DCE-MRI were significantly higher in BME than in normal bone marrow (P < 0.001). No significant correlation was found between BME quantification and clinical evaluations. A highly reproducible semi-automatic method for quantifying BME lesion burden in RA was developed, which may enhance our capability of predicting disease progression and monitoring treatment response.

Pituitary Infundibulum Hemangioblastoma Detected by Dynamic Enhancement MRI

Pituitary Infundibulum Hemangioblastoma Detected by Dynamic Enhancement MRI

Value of MR imaging in the differentiation of benign and malignant orbital tumors in adults

PurposeTo prospectively evaluate magnetic resonance (MR) imaging including dynamic contrast-enhanced MR imaging in the differentiation of benign from malignant orbital masses and to evaluate which MR imaging features are most predictive of malignant tumors.Materials and methodsThe study was approved by the institutional review board and signed informed consent was obtained. Nonenhanced, static, and dynamic contrast-enhanced MR imaging was performed in 102 adult patients with an orbital mass. Diagnosis was based on histologic findings. MR imaging features of benign and malignant orbital lesions were evaluated correlated with histological findings. Multivariate logistic regression analysis was employed to identify the best combination of MR imaging features that might be predictive of malignancy.ResultsNonenhanced, static, and dynamic enhancement MR imaging was significantly superior to two other models in prediction of malignancy (p < 0.05). Multivariate logistic regression analysis identified that the most discriminating MR imaging features were isointense mass on T2-weighted imaging and a washout-type time–intensity curve for both observers.ConclusionNonenhanced, static, and dynamic enhancement MR imaging improved differentiation between benign and malignant orbital masses in adult patients.

Preoperative staging of liver metastases from uveal melanoma by magnetic resonance imaging (MRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET)

Background Microscopically complete (R0) resection of metastases from uveal melanoma prolongs median overall survival compared to incomplete surgery. The aim of this study was to compare the sensitivity of dynamic-enhanced magnetic resonance imaging (MRI) with fluorodeoxyglucose-positron emission tomography (FDG-PET) in the preoperative diagnosis of liver metastases from uveal melanoma. Patients and methods Fifteen consecutive patients (mean age: 56 years) underwent FDG-PET and liver MRI. Extrahepatic metastatic disease was excluded by whole body computed tomography and bone scintigraphy. MRI and FDG-PET were performed with a mean of 19 days (range: 1–30) before surgery. Imaging findings were compared with surgical (including intraoperative ultrasonography) and histological findings on a lesion by lesion analysis. Results R0 resection was performed in 12 patients. A total of 28 lesions were resected with 27 histologically proven metastases. Nine lesions were smaller than 5 mm, 7 measured 5–10 mm and 11 were larger than 10 mm. Sensitivity and positive predictive value were 67% and 95% for MRI compared to 41% and 100% for FDG-PET. The difference between the two modalities was statistically significant ( p = 0.01; McNemar test). In remaining 3 patients, diffuse miliary disease (>10 capsular lesions) was discovered intraoperatively, and was suspected on preoperative MRI in 2 cases. Only one extrahepatic lesion identified by FDG-PET was falsely positive. Conclusions In this preliminary study, MRI was superior to FDG-PET for staging of liver metastases from uveal melanoma. Although miliary disease was suggested by MRI in some cases, preoperative confirmation remains imperfect.

Evaluating transcatheter arterial chemoembolization for primary hepatic cancer by magnetic resonance diffusion-weighted imaging

Evaluating transcatheter arterial chemoembolization for primary hepatic cancer by magnetic resonance diffusion-weighted imaging

The value of quantitativeparameters of dynamic-enhanced MRI and the significance of the maximum linearity sloperatio in the differential diagnosis of benign and malignant breast lesions

：Objective To find theeffective quantitative parameters for the differentiation of the breast lesions using thepost-processing of time.signal curve of 3D dynamic-enhanced MRI.Methods Thirty patientswith 35 lesions underwent 3D dynamic-enhanced MRI and the time-signal cHIve wasdeduced.The four quantitative parameters including SImax,PH,Slope and SlopeR were analyzedin benign andmalignant lesions of the breast.Independent samples t test and rank sum testwere used for the statistics.Results Seyenteen benign lesions and 18 malignant lesionswere included in this study.The SImax(M)of benign and malignant lesions were 375.2 and158.1,the 95% confidence intervals of SImax were 278.2-506.0 and 160.5-374.8.The PH(M)ofbenign and malignant lesions were 114.4 and 87.8,the 95% confidence intervals of PH were73.7-196.5 and 71.3-162.9.The Slope(M) of benign and malignant lesions were 22.3×10-3 and44.0×10-3,the 95% confidence intervals of Slope were 13.7×10-3-41.1×10-3 and 46.1×10-3-81.8×10-3.TheSlope(M) of benign and malignant lesions were 2.6 and11.4,the 95% confidenceintervals of SlopeR were 1.9-3.4 and 9.8-14.5.There were no significant differences onSImax and PH between benign and malignant lesions(P>0.05).The significant differencesexisted on Slope(P<0.01)and SlopeR(P<0.01)between benign and malignant lesions ofthe breast.Conclusion SlopeR is a very effective parameter in t}le differential diagnosisof breast lesions.

Detection of small hepatocellular carcinoma: Comparison of dynamic enhancement magnetic resonance imaging and multiphase multirow-detector helical CT scanning

To compare the gadolinium-enhanced multiphase dynamic magnetic resonance imaging (MRI) and multiphase multirow-detector helical CT (MDCT) scanning for detection of small hepatocellular carcinoma (HCC). MDCT scanning and baseline MRI with SE T1-WI and T2-WI sequence combined with FMPSPGR sequence were performed in 37 patients with 43 small HCCs. Receiver operating characteristic (ROC) curves were plotted to analyze the results for modality. The areas below ROC curve (Az) were calculated. There was no statistical difference in dynamic enhancement MDCT and MRI. The detection rate of small HCC was 97.5%-97.6% on multiphase MDCT scanning and 90.7%-94.7% on MRI, respectively. The sensitivity of detection for small HCC on MDCT scanning was higher than that on dynamic enhancement MRI. The sensitivity of detection for minute HCC (tumor diameter < or = 1 cm) was 90.0%-95.0% on MDCT scanning and 70.0%-85.0% on MRI, respectively. MDCT scanning should be performed for early detection and effective treatment of small HCC in patients with chronic hepatitis and cirrhosis during follow-up.

A model for quantitative changes in the magnetic resonance parameters of muscle in children after therapeutic irradiation

This study aimed to develop objective models of radiation effects on musculature in children with soft tissue sarcoma using treatment dosimetry and clinical and quantitative magnetic resonance imaging (MRI) parameters that may be used to guide treatment planning or predict side effects. In the initial 13 patients undergoing external beam radiation therapy (RT) on a Phase II study of conformal or intensity-modulated RT for the treatment of soft tissue sarcoma approved by an Institutional Review Board, we evaluated quantitative MRI changes in the musculature to assess radiation-related treatment effects. Patients with soft tissue sarcoma, including Ewing's sarcoma, had quantitative T1, T2 and dynamic enhanced MRI (DEMRI) performed before, during (Week 4) and after RT (Week 12). Regions of interest were selected in consistent locations within and outside the high-dose regions (on ipsilateral and contralateral sides when available). Mean RT dose, T1, T2 and DEMRI parameters were calculated and modeled using a mixed random coefficient dose model. The mean doses to the high- and low-dose regions were 56.4 Gy (41.8-75.3 Gy) and 13.0 Gy (0.1-37.5 Gy), respectively. Compared with tissues distant from the tumor bed, maximal enhancement was significantly increased in tissues adjacent to the tumor/tumor bed prior to RT (60.6 vs. 44.2, P=.045) and remained elevated after 12 weeks. T1 was significantly elevated in tissues adjacent to the tumor bed prior to RT (942.4 vs. 759.0, P=.0078). The slope of longitudinal change in T1 was greater for tissues that received low-dose irradiation than those that received high-dose irradiation (P=.0488). The effect of dose on the slope of T2 was different (P=.0333) when younger and older patients are compared. Acute affects of irradiation in muscle are quantifiable via MRI. These models provide evidence that quantifiable MRI parameters may be correlated with patient parameters of radiation dose and clinical factors including patient age. Long-term follow-up will be required to determine if acute changes correlate with clinically significant late effects.