Contrast-enhanced MRI Examinations Research Articles

Three-Dimensional Radial VIBE Sequence for Contrast-Enhanced Brain Imaging: An Alternative for Reducing Motion Artifacts in Restless Children.

The purpose of this study was to evaluate the usefulness of radially sampled 3D fat-suppressed T1-weighted gradient-echo sequences (radial volumetric interpolated breath-hold examination [radial VIBE]) for contrast-enhanced brain MRI of children through comparison with a magnetization-prepared rapid-acquisition gradient-echo (MP-RAGE) sequence. Sixty-five consecutive contrast-enhanced brain MRI examinations performed with axial MP-RAGE and radial VIBE sequences were included. For quantitative analysis, coefficients of variation of gray matter and white matter and CSF and relative contrast between tissue types (gray matter and white matter, gray matter and CSF, and white matter and CSF) for each sequence were calculated. For qualitative assessment, motion, pulsation artifacts, overall image quality, and lesion conspicuity were retrospectively scored on a 5-point scale. Quantitative and qualitative subgroup analyses were performed for patients with serious motion artifacts. Images obtained with the radial VIBE sequence had fewer motion and pulsation artifacts than those obtained with the MP-RAGE sequence (MP-RAGE vs radial VIBE motion score, 3.57 ± 1.00 vs 4.52 ± 0.51; pulsation score, 3.57 ± 0.60 vs 4.91 ± 0.21; all p < 0.001). Among 25 images with serious motion artifacts, radial VIBE images had significantly higher scores for all qualitative parameters, including overall image quality, than did MP-RAGE images (overall image quality for MP-RAGE vs radial VIBE, 2.63 ± 0.82 vs 3.42 ± 0.55, p < 0.001). The study showed that a radial fat-suppressed T1-weighted gradient-echo sequence is a viable alternative to conventional cartesian acquisition for contrast-enhanced brain imaging of restless children.

Magnetic Resonance Imaging Predicts Histopathological Composition of Ileal Crohn's Disease.

Recently, smooth muscle hypertrophy has been suggested to be a contributor to small bowel lesions secondary to Crohn's disease [CD], in addition to inflammation and fibrosis. Here, we assess the value of magnetic resonance imaging [MRI] for the characterisation of histopathological tissue composition of small bowel CD, including inflammation, fibrosis, and smooth muscle hypertrophy. A total of 35 consecutive patients [male/female 17/18, mean age 33 years] with ileal CD, who underwent small bowel resection and a preoperative contrast-enhanced MRI examination within 1 month before surgery, were retrospectively included. Image assessment included qualitative [pattern/degree of enhancement, presence of ulcerations/fistulas/abscesses] and quantitative parameters [wall thickness on T2/T1-weighted images [WI], enhancement ratios, apparent diffusion coefficient [ADC], Clermont and Magnetic Resonance Index of Activity [MaRIA] scores). MRI parameters were compared with histopathological findings including active inflammation, collagen deposition, and muscle hypertrophy using chi square/Fisher or Mann-Whitney tests and univariate/multivariate logistic/linear regression analyses. Forty ileal segments were analysed in 35 patients. Layered pattern at early-post-contrast phase was more prevalent (odds ratio [OR] = 8; p = 0.008), ADC was significantly lower [OR = 0.005; p = 0.022], and MaRIA score was significantly higher [OR = 1.125; p = 0.022] in inflammation grades 2-3 compared with grade 1. Wall thickness on T2WI was significantly increased [OR = 1.688; p = 0.043], and fistulas [OR = 14.5; p = 0.017] were more prevalent in segments with disproportionately increased muscle hypertrophy versus those with disproportionately increased fibrosis. MaRIA/Clermont scores, wall thickness on T1WI and T2WI, and ADC were all significantly correlated with degree of muscular hypertrophy. MRI predicts the degree of inflammation, and can distinguish prominent muscle hypertrophy from prominent fibrosis in ileal CD with reasonable accuracy (area under receiver operating characteristic curve [AUROC] > 0.7).

T2*-Correction in Dynamic Contrast-Enhanced Magnetic Resonance Imaging of Glioblastoma From a Half Dose of High-Relaxivity Contrast Agent.

The aim of this study was to evaluate the arterial input function (AIF) and tissue enhancement time curve (tissue function [TF]) obtained after the administration of a half-dose gadobenate dimeglumine (0.05-mmol/kg body weight [bw]) compared with a full dose (0.1-mmol/kg bw) of a standard-relaxivity contrast agent. We enrolled 40 adult patients with glioblastoma in an interindividual comparative study. Patients were randomized to 1 of the 2 study arms: 20 patients received 0.1-mmol/kg bw of gadoterate; the other 20 patients received 0.05-mmol/kg bw of gadobenate. The patients underwent dynamic contrast-enhanced magnetic resonance imaging examinations. Arterial input function, tissue enhancement time curve (TF), tumor transfer rate (K), and tumor extracellular-extravascular volume fraction (Ve) were calculated for each patients. Averaged AIF, TF, K, and Ve of both groups were compared. A significant difference (P = 0.001) between the peak AIF values obtained with the 2 different gadolinium-based contrast agents was observed. No difference was found between TFs (P = 0.35). Comparison on kinetic parameters revealed a significant difference for K (P = 0.047) but no difference for Ve (P = 0.74). The administration of half dose of the high-relaxivity contrast agent gadobenate is effective in improving AIF by reducing T2*-shortening effects on dynamic contrast-enhanced magnetic resonance imaging and ensuring at the same time an adequate signal enhancement in tumor tissue. The use of 0.05-mmol/kg bw of gadobenate not only is feasible but also can lead to a better estimation of K based on a more accurate AIF assessment.

Preoperative dynamic contrast-enhanced MRI can reduce the rate of tumor-positive resection margins after breast conserving surgery in patients with early non-mass breast carcinoma

Objective: To investigate the value of preoperative dynamic contrast-enhanced MRI in reducing the rate of tumor-positive resection margins after breast conserving surgery in patients with early non-mass breast carcinoma. Methods: Seventy-two patients with early non-mass breast carcinoma received ultrasonographic and mammographic examination and subsequently underwent dynamic contrast-enhanced MRI examination before breast conserving surgery. The control group consisted of 74 patients who had early non-mass breast carcinoma. They only received ultrasonographic and mammographic examination and didn't undergo contrast-enhanced MRI examination. The comparison of the rate of tumor-positive resection margins between two groups was performed. The MRI findings that had the significant influence on the rate of tumor-positive resection margins were analyzed using Logistic regression model. Results: In 28 patients (28/72, 38.9%), dynamic contrast-enhanced MRI could correct or supplement the ultrasonographic and mammographic findings and resulted in the reasonable change of surgical program. The preoperative MRI examination group (n=30) had lower rate of tumor-positive resection margins than control group for invasive ductal carcinoma (23.3% vs 40.0%, P=0.02), but there was no significant difference (21.4% vs 26.9%, P=0.10) between two groups for ductal carcinoma in situ (n=28). The preoperative MRI examination group (n=14) had lower rate of tumor-positive resection margins than control group for the other pathologic types of breast carcinoma (14.3% vs 38.9%, P=0.02). The statistical analysis on the basis of Logistic regression model showed that some main MRI findings, including change surrounding the tumor, distance between tumor and nipple and tumor size, had the significant influence on the rate of tumor-positive resection margins. Conclusion: Preoperative dynamic contrast-enhanced MRI significantly increased the accuracy of resection margins evaluation, and greatly reduced the rate of tumor-positive resection margins after breast conserving surgery in patients with early non-mass breast carcinoma.

Revisiting Nonmass Enhancement in Breast MRI: Analysis of Outcomes and Follow-Up Using the Updated BI-RADS Atlas.

The purpose of this study is to assess the frequency of reclassification of nonmass enhancement (NME) as background parenchymal enhancement (BPE) and to determine positive predictive values (PPVs) of NME descriptors using the revised BI-RADS atlas. A retrospective review of our institution's MRI database from January 1, 2009, through March 30, 2012, identified 6220 contrast-enhanced breast MRI examinations. All findings prospectively assessed as NME and rated as BI-RADS categories 3, 4, and 5 (n = 386) were rereviewed in consensus by two radiologists who were blinded to pathologic findings with the fifth edition of the BI-RADS lexicon. Findings considered as postsurgical, associated with known cancers, NME given a BI-RADS category 3 assessment before 2009, previously biopsied, and those reclassified as BPE, focus, or mass were excluded (n = 181). Medical records were reviewed for demographics and outcomes. Two hundred five women were included (mean age, 48.8 years; range, 21-84 years). Seventy-seven of 386 findings (20.0%) were reclassified as BPE, and patients with BPE were younger than those with NME (mean age, 43.9 years; range, 31-62 years) (p = 0.003). Pathology results for 144 of 205 (70.2%) patients included 52 malignant, 11 high-risk, and 81 benign lesions. The highest PPVs for distribution patterns were 34.5% (10/29) for segmental and 100.0% (3/3) for diffuse distribution. The highest PPVs for internal enhancement patterns were 36.7% (11/30) for clustered ring enhancement and 27.5% (11/40) for clumped enhancement. No difference for NME malignancy rate was noted according to BPE (10/52 [19.2%] marked or moderate; 42/153 [27.5%] mild or minimal, p = 0.24). Thirty-two percent (17/52) of malignant NMEs had high T2 signal. Careful assessment of findings as BPE versus NME can improve PPVs, particularly in younger women. Although clustered ring enhancement had one of the study's highest PPVs, this number falls below previously published rates. Reliance on T2 signal as a benign feature may be misleading, because one-third of malignancies had T2 signal.

Rigid-body motion correction of the liver in image reconstruction for golden-angle stack-of-stars DCE MRI.

Respiratory motion can affect pharmacokinetic perfusion parameters quantified from liver dynamic contrast-enhanced MRI. Image registration can be used to align dynamic images after reconstruction. However, intra-image motion blur remains after alignment and can alter the shape of contrast-agent uptake curves. We introduce a method to correct for inter- and intra-image motion during image reconstruction. Sixteen liver dynamic contrast-enhanced MRI examinations of nine subjects were performed using a golden-angle stack-of-stars sequence. For each examination, an image time series with high temporal resolution but severe streak artifacts was reconstructed. Images were aligned using region-limited rigid image registration within a region of interest covering the liver. The transformations resulting from alignment were used to correct raw data for motion by modulating and rotating acquired lines in k-space. The corrected data were then reconstructed using view sharing. Portal-venous input functions extracted from motion-corrected images had significantly greater peak signal enhancements (mean increase: 16%, t-test, P < 0.001) than those from images aligned using image registration after reconstruction. In addition, portal-venous perfusion maps estimated from motion-corrected images showed fewer artifacts close to the edge of the liver. Motion-corrected image reconstruction restores uptake curves distorted by motion. Motion correction also reduces motion artifacts in estimated perfusion parameter maps. Magn Reson Med 79:1345-1353, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Correlation between high signal intensity in cerebrum nucleus on unenhanced T1-weighted MR images and number of previous gadolinium-based contrast agent administration

To explore the correlation between the number of previous gadolinium-based contrast agent administrations and high signal intensity (SI) in the cerebrum nucleus on unenhanced T1-weighted magnetic resonance images. Thirty-nine patients who previously underwent at least three contrast-enhanced brain MRI examinations were enrolled in the study. The right globus pallidus, right thalamus, right dentate nucleus, pons and white matter of right frontal lobe were selected as region of interests (ROI). The mean SIs of the ROI were measured on unenhanced T1-weighted images. The SI ratios of globus pallidus, right thalamus, right dentate nucleus and pons to white matter were calculated, respectively. The correlation of SI ratio variation with the number of previous contrast agent administration and clinical features was analyzed with Spearman analysis. The dentate nucleus-to-white matter SI ratios of the last and first MRI scan were 1.113±0.136 and 1.014±0.096(P<0.01), respectively; while the SI ratio differences between the last and first MRI scan of globus pallidus-to-white matter, the thalamus-to-white matter and the pons-to-white matter were not significant (all P>0.05). The dentate nucleus-to-white matter SI ratio was correlated with the number of previous gadolinium-based contrast agent administrations (r=0.329, P<0.05), but not with age, sex, underlying disease, treatment and history of diabetes (all P>0.05). High SI in the dentate nucleus on unenhanced T1-weighted images may be a consequence of the number of previous gadolinium-based contrast agent administrations.

On a fractional order calculus model in diffusion weighted breast imaging to differentiate between malignant and benign breast lesions detected on X-ray screening mammography.

ObjectiveTo evaluate a fractional order calculus (FROC) model in diffusion weighted imaging to differentiate between malignant and benign breast lesions in breast cancer screening work-up using recently introduced parameters (βFROC, DFROC and μFROC).Materials and methodsThis retrospective analysis within a prospective IRB-approved study included 51 participants (mean 58.4 years) after written informed consent. All patients had suspicious screening mammograms and indication for biopsy. Prior to biopsy, full diagnostic contrast-enhanced MRI examination was acquired including diffusion-weighted-imaging (DWI, b = 0,100,750,1500 s/mm2). Conventional apparent diffusion coefficient Dapp and FROC parameters (βFROC, DFROC and μFROC) as suggested further indicators of diffusivity components were measured in benign and malignant lesions. Receiver operating characteristics (ROC) were calculated to evaluate the diagnostic performance of the parameters.Results29/51 patients histopathologically revealed malignant lesions. The analysis revealed an AUC for Dapp of 0.89 (95% CI 0.80–0.98). For FROC derived parameters, AUC was 0.75 (0.60–0.89) for DFROC, 0.59 (0.43–0.75) for βFROC and 0.59 (0.42–0.77) for μFROC. Comparison of the AUC curves revealed a significantly higher AUC of Dapp compared to the FROC parameters DFROC (p = 0.009), βFROC (p = 0.003) and μFROC (p = 0.001).ConclusionIn contrast to recent description in brain tumors, the apparent diffusion coefficient Dapp showed a significantly higher AUC than the recently proposed FROC parameters βFROC, DFROC and μFROC for differentiating between malignant and benign breast lesions. This might be related to the intrinsic high heterogeneity within breast tissue or to the lower maximal b-value used in our study.

Paraspinal Edema Is the Most Sensitive Feature of Lumbar Spinal Epidural Abscess on Unenhanced MRI.

Spinal epidural abscess (SEA) is a serious infection requiring prompt treatment and potential neurosurgical intervention. Although contrast-enhanced spine MRI is the mainstay for diagnosis of SEA, unenhanced MRI is typically performed for patients with nonspecific symptoms or insufficient clinical information. We evaluated the sensitivity and specificity of imaging features suggestive of SEA at unenhanced spine MRI. We searched our database for contrast-enhanced lumbar spine MRI examinations from January 1, 2000, through August 1, 2014, with "epidural abscess" in the report. We included 68 patients older than 18 years with an enhancing epidural collection at MRI and surgical (60%), microbiologic (15%), or clinical (25%) confirmation of SEA. Sixty-eight age- and sex-matched control subjects without SEA were also selected. Three readers scored unenhanced MR images on the degree of psoas and paraspinal muscle edema, extent of bone marrow edema, and abnormal disk signal. Paraspinal edema was highly sensitive (97%) for SEA, with lower sensitivities for psoas (54%), bone marrow (65%), and disk edema (66%). Each of these markers was highly significant in univariate analysis (p < 0.001). A multivariate logistic regression model adjusting for age and sex found that paraspinal (p < 0.001) and bone marrow edema (p = 0.006) were significant independent predictors of SEA (odds ratio, 58; p < 0.001), with a trend toward significance for psoas edema and abnormal disk signal. Psoas muscle edema was the most specific (96%) finding for the presence of SEA. Paraspinal edema is highly sensitive for SEA. Familiarity with the findings for SEA at unenhanced MRI could help expedite further definitive evaluation when contrast agent is not administered.

Survey of gadolinium-based contrast agent utilization among the members of the Society for Pediatric Radiology: a Quality and Safety Committee report.

Gadolinium-based contrast agents (GBCAs) have been used for magnetic resonance (MR) imaging over the last three decades. Recent reports demonstrated gadolinium retention in patients' brains following intravenous administration. Since gadolinium is a highly toxic heavy metal, there is a potential for adverse effects from prolonged retention or deposition, particularly in children. For this reason, the Society (SPR) for Pediatric Radiology Quality and Safety committee conducted a survey to evaluate the current status of GBCAs usage among pediatric radiologists. To assess the usage of GBCAs among SPR members. An online 15-question survey was distributed to SPR members. Survey questions pertained to the type of GBCAs used, protocoling workflow, requirement of renal function or pregnancy tests, and various clinical indications for contrast-enhanced MRI examinations. A total of 163 survey responses were compiled (11.1% of survey invitations), the majority of these from academic institutions in the United States. Ninety-four percent reported that MR studies are always or usually protocoled by pediatric radiologists. The most common GBCA utilized by survey respondents were Eovist (60.7%), Ablavar (45.4%), Gadovist (38.7%), Magnevist (34.4%) and Dotarem (32.5%). For several clinical indications, survey responses regarding GBCA administration were concordant with American College of Radiology (ACR) Appropriateness Criteria, including seizures, headache and osteomyelitis. For other indications, including growth hormone deficiency and suspected vascular ring, survey responses revealed potential overutilization of GBCAs when compared to ACR recommendations. Survey results demonstrate that GBCAs are administered judiciously in children, yet there is an opportunity to improve their utilization with the goal of reducing potential future adverse effects.

Clinical Utility of Breast MRI in the Diagnosis of Malignancy After Inconclusive or Equivocal Mammographic Diagnostic Evaluation.

The purpose of this study was to determine the clinical utility of breast MRI for diagnosing malignancy in women with equivocal mammographic findings but no symptoms. Retrospective review of an institutional MRI database of 7332 contrast-enhanced breast MRI examinations from January 1, 2009, through December 31, 2012, yielded the records of 296 (4.0%) examinations of 294 women without symptoms who underwent MRI for mammographic findings uncertain at diagnostic evaluation. Imaging findings, histopathologic results, and patient demographics were obtained from the electronic medical record. The mean patient age was 55 years (range, 29-83 years). Mammographic lesion type (n = 294) included 89 focal asymmetries, 76 asymmetries, 64 masses, 44 architectural distortions, 17 surgical scar versus lesion, and four miscellaneous lesions. Diagnostic ultrasound, performed on 286 of 294 (97.3%) lesions at mammographic evaluation, showed an ultrasound correlate in 37 (12.9%) lesions, equivocal correlate in 48 (16.8%), and no ultrasound correlate in 201 (70.3%). MRI examination of 294 index lesions showed a correlate in 133 (45.2%) and no correlate in 161 (54.8%). Forty of 294 (13.6%) index lesions were malignant, 37 (92.5%) with an MRI correlate and three (7.5%) without an MRI correlate. Among 250 patients who underwent biopsy or had 2 or more years of imaging stability, the sensitivity, specificity, negative predictive value, and positive predictive value of breast MRI for malignancy were 92.5%, 62.4%, 97.8%, and 31.9%. Forty-four of 294 (15.0%) patients had lesions incidentally found at MRI; 7 of 41 (17.1%) lesions that were biopsied or were stable for at least 1 year were malignant. Problem-solving breast MRI for inconclusive mammographic findings helps identify malignancies with high sensitivity and a high negative predictive value.

Abstract PD3-05: Effect of MR imaging contrast kinetic thresholds for prediction of neoadjuvant chemotherapy response in breast cancer subtypes – Results from ACRIN 6657 / I-SPY 1 trial

Abstract Background: Breast MRI has the potential to non-invasively measure response to neoadjuvant chemotherapy (NACT). We studied the effect of varying two analytic parameters used to define MRI-measured tumor volume in the prediction of pathologic complete response (pCR) to NACT and to determine if optimization of these parameter thresholds would improve the prediction of pCR. Methods: Women with locally advanced breast cancer (tumor size ≥ 3cm) were enrolled in the ACRIN 6657 / I-SPY 1 TRIAL. Each patient had up to four dynamic contrast-enhanced MRI examinations: before NACT (MR1), after one cycle of NACT (MR2), between the anthracycline-based regimen and taxane (MR3), and after NACT and prior to surgery (MR4). Breast cancer was stratified by subtypes of hormone receptor (HR), and human epidermal growth factor receptor 2 (HER2) status: HR+/HER2, HER2+, and triple negative ((TN) HR-/HER2-). MRI-measured functional tumor volume (FTV) and change in FTV (ΔFTV) were investigated as predictors of the outcome pCR. FTV is defined as the image volume with enhancement kinetics exceeding both an early percentage enhancement threshold (PEt) and a signal enhancement ratio threshold (SERt). Primary study analysis used empirically determined values. For this study PEt was varied from 30% to 200% in 10% intervals, and SERt was varied from 0.0 to 2.0 in 0.2 unit intervals. FTV was measured at each examination (FTV1, FTV2, FTV3, FTV4). ΔFTV was measured relative to the first examination (ΔFTV2, ΔFTV3, ΔFTV4). For each pair of varied PEt and SERt thresholds, the absolute and relative FTVs were re-measured and analyzed for discrimination of pCR using the area under the curve (AUC) of the receiver operating characteristic curve. Results: A total of 116 patients were included from the ACRIN 6657 / I-SPY 1 TRIAL who had complete data on all four MRI visits, HR/HER2 status, and pCR outcome. Mean age was 48 years old (range 29-69). The full cohort of 116 patients was divided into subgroups: 45 (39%) HR+/HER2-; 39 (34%) HER2+; and 30 (26%) TN. When stratified by subtypes, lower AUCs with less variation were observed in patients with HER2+ cancer than patients with HR+/HER2- and TN breast cancer. When examining prediction by visit, maximum AUCs were found at later time points in all patient cohorts. Specifically, maximum AUC was observed for the full cohort at ΔFTV3 with AUC of 0.78 (CI: 0.69–0.87) when PEt=130% and SERt=0; for HR+/HER2- subtype at ΔFTV3 with AUC of 0.9 (CI: 0.84–0.97) when PEt=130% and SERt=0 were the same as in the full cohort; for HER2+ subtype at FTV3 with AUC of 0.77 (CI: 0.62–0.92) when PEt=70%/SERt=1.4; for triple negative at FTV4 with AUC of 0.89 (CI: 0.76–1) when PEt=40%/SERt=2.0. Conclusion: This analysis suggests that the thresholds of MRI quantitative DCE measurements may need to be adjusted by breast cancer subtype to improve the predictive performance. The PEt threshold may need to be set higher in HR+/HER2- than other subtypes, which may be due to higher background parenchymal enhancement among HR+ patients. SER threshold may need to be set at higher level for triple negative subtype. A validation is underway in I-SPY 2, with a larger patient population. Citation Format: Li W, Arasu V, Jones EF, Newitt DC, Wilmes LJ, Kornak J, Esserman LJ, Hylton NM. Effect of MR imaging contrast kinetic thresholds for prediction of neoadjuvant chemotherapy response in breast cancer subtypes – Results from ACRIN 6657 / I-SPY 1 trial [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD3-05.

Cryoinjury-induced acute myocardial infarction model and ameroid constrictor-induced ischemic heart disease model in adult micro-mini pigs for preclinical studies

BackgroundCoronary artery diseases (CAD) are the most commonly occurring disorders in the developed countries. Development of new therapeutics and their success in clinical studies require confirmation of therapeutic effects in large animal models. Swine is an ideal animal model because their anatomical features are similar to humans. However, sometimes their large body size hampers translational research, particularly in cell or tissue transplantation procedures for adult stage and long-term observation studies. We have been developing the smallest experimental pig, called micro-mini pigs (MMPs), for regenerative medicine.MethodsFive- to 14-month-old mature MMPs were used (n = 15, body weight: 13.4 ± 2.14 kg). In the acute myocardial infarction (AMI) model, AMI was induced by cryoinjury (CI). In the ischemic heart disease (IHD) model, IHD was induced using an ameroid constrictor (AC) that was applied to the left anterior descending artery, with the diagonal branches ligated. Cardiac function in both models was assessed by magnetic resonance imaging (MRI) with late gadolinium enhancement, and coronary angiography (CAG) was performed to evaluate the collateral arteries. Animals were sacrificed 4 weeks after procedures to evaluate the pathological changes.ResultsOn MRI, the ejection fraction in CI-induced AMI models decreased from 57.7 ± 3.2% to 35.8 ± 4.7% (Δ62.2%, p = 0.012) (n = 8). In contrast, AC also impaired cardiac function, but some pigs did not develop heart failure due to the development of collateral branches (pre: 54.4 ± 4.4%, post: 41.1 ± 8.0%, Δ75.7%, p = 0.028 [n = 7]). Gadolinium contrast-enhanced MRI and pathological examination confirmed scarring in both models. The proportion of scar area in the left ventricular region of CI-induced AMI models vs. AC-induced IHD models was 19.4% vs. 10.3% (p = 0.046) (MRI) and 17.6% vs. 9.2% (p = 0.046) (pathology). Immunohistological analysis also showed the presence of marked neovascularization in AC models, which led to greater variation in the impairment of cardiac function.ConclusionsMMPs are the smallest available swine for experimental use that are suitable for translational research. They allow for long-term observation of adult pathology. Both models of AMI and IHD were successfully established in MMPs. The MMP preclinical heart failure model may accelerate further development of new treatments for CAD.

Alternatives to GBCA: Are We There Yet?

Gadolinium has been widely used as the contrast agent of choice for magnetic resonance imaging (MRI). However, gadolinium administration is not always desired due to its inherent enhancement properties and potential side effects (nephrogenic systemic fibrosis). This article reviews gadolinium alternatives, iron-, and manganese- based agents, and their current clinical usage for contrast-enhanced MRI examinations.

Calcifying fibrous pseudotumor of the adrenal gland: A rare case report

Calcifying fibrous pseudotumor (CFP) is a rare benign soft tissue lesion. We herein present an extremely rare case of CFP of the adrenal gland. A 32-year-old male patient presented to our hospital with a tumor-like lesion in the area of the left adrenal gland detected by ultrasound during a routine check-up several days prior. Contrast-enhanced magnetic resonance imaging examination revealed a solitary, well-circumscribed mass, in close proximity to the medial arterial branch of the left adrenal gland. Histological examination revealed that the tumor consisted of sheets of varying amount of inflammatory cell infiltration; interstitial fibrosis and psammomatous calcifications were also observed. To the best of our knowledge, this is the third case of CFP occurring in the adrenal gland in the published literature. We herein report the findings of this case and review the two previously reported cases of CFP of the adrenal gland with valuable information.

The value of conventional MRI combined with diffusion weighted imaging in the differential diagnosis of orbital lymphoproliferative disorders

Objective To investigate the diagnostic value of conventional MRI combined with DWI in the differential diagnosis of orbital lymphoproliferative disorders (LPD). Methods As a retrospective study, 42 patients were enrolled, including 23 orbital lymphoma and 19 benign orbital LPD confirmed pathologically or clinically. These patients underwent conventional MR, DWI and contrast-enhanced MRI examination of orbit. Qualitative MR imaging features [location, margin, patient ratio of involved quadrants (≥2), signal intensity, flow void sign , sinusitis] and quantitative features [ADC and contrast enhanced ratio of the lesion to temporal muscle (CER)] were evaluated. Chi-square test and t test were used for the analysis of qualitative and quantitative features between lymphoma and benign orbital LPD groups, respectively. Multivariate Logistic regression analysis was employed to identify the significant variable for predicting malignant LPD. ROC analysis was used to evaluate the ability of the diagnostic models established based on identified variables. Results Flow void sign (9 lymphomas and 17 benign LPDs) and sinusitis (5 lymphomas and 13 benign LPDs) were statistically significant (P 0.05). Both ADC [(0.79±0.09)×10-3 mm2/s of lymphoma, (1.29±0.35)×10-3 mm2/s of benign LPD] and CER (1.43±0.17 of lymphoma, 1.79±0.31 of benign LPD) between the two groups had significant difference (t=-6.630, -8.257;P<0.01). Multivariate logistic regression analysis showed that ADC value, CER and flow void sign were significant variables for predicting malignant orbital LPD (P<0.05). ROC curve showed that ADC value was the most significant single variable in differentiating orbital LPD [threshold value, 0.74×10-3 mm2/s; areas under ROC curve (AUC), 0.97; sensitivity, 87.0%; specificity, 94.7%]. Combination of ADC and CER could further improve the specificity in differentiating benign from malignant orbital LPD (AUC, 0.90; sensitivity, 78.3%; specificity, 100.0%, accuracy 88.1%). Conclusions ADC, CER and flow void sign on T2WI were significant variables for predicting malignant orbital LPD. ADC value was the most significant single variable. Combination of ADC and CER could further improve the specificity in differentiating benign from malignant orbital LPD. Key words: Orbit; Lymphoma; Magnetic resonance imaging

False-Positive Tumor Enhancement After Cryoablation of Renal Cell Carcinoma: A Prospective Study.

The objective of the present study was to prospectively evaluate the frequency of false-positive tumor enhancement after cryoablation of renal cell carcinoma (RCC). Patients who underwent cryoablation of a single RCC smaller than 7 cm were enrolled in the study. Contrast-enhanced MRI examinations were performed at five time points (2-3 days, 5-7 days, 1 month, 3 months, and 6 months) after cryoablation. For patients with completely ablated RCCs, the frequency and patterns of false-positive tumor enhancement and the risk factors associated with such enhancement were evaluated at each time point. The planned protocol was completed by 30 of the 33 enrolled patients (90.9%) with 30 RCCs (mean [± SD] size, 23.0 ± 8.7 cm; range, 1.0-4.7 cm). Complete tumor ablation was achieved for 25 RCCs (83.3%). Residual tumors were found in association with the other five RCCs (16.7%). Of the 25 completely ablated RCCs, false-positive tumor enhancement was observed for 15 tumors (60.0%) at 2-3 days after cryoablation; it continued to be observed for 13 tumors (52.0%) at 5-7 days and for one tumor (4.0%) at 1 month after cryoablation. The rate of false-positive tumor enhancement noted at 5-7 days after cryoablation was statistically significantly higher for clear cell RCCs (63.2%; 12/19) than for other RCC subtypes (16.7%; 1/6; p < 0.05). False-positive tumor enhancement frequently continues to be observed, particularly in clear cell RCCs, until 1 month after cryoablation of RCCs.

Myocardial T1 maps reflect histological findings in acute and chronic stages of myocarditis in a rat model.

BackgroundCardiovascular magnetic resonance offers both diagnostic and prognostic information in myocarditis. Using an established animal model of myocarditis, the aim of this study was to measure myocardial T1 before the onset, in the acute and in the chronic phases of the disease and to compare its course with histological and immunohistochemistry findings.MethodsMale young Lewis rats were immunized with 0.25 mg porcine myocardial myosin into the rear footpads on day 0. Native and contrast-enhanced ECG-triggered cardiac MRI examinations were performed before immunization on day 0 and on days 14, 21 and 35. Left ventricular function, pre- and post- contrast T1 parameters and LGE images were assessed using Small animal look-locker inversion recovery (SALLI). For each of the indicated time points a minimum of 4 rats were randomly sacrificed for pathological investigations including conventional histology (HE and Sirius-Red staining) and immunohistochemistry (CD 68) investigations.ResultsAll immunized rats developed myocarditis (morbidity 100 %). Histologically we observed increased wall thickness with biventricular macrophage-rich mixed inflammatory infiltrates. All rats with a histologically severe myocarditis showed increased native T1 and decreased post-contrast T1 of the myocardium.ConclusionsThe assessment of native T1 and post-contrast T1 allows accurate differentiation between healthy myocardium and myocardium with inflammation and also between the acute and chronic phases of the disease.

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

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

Comprehensive assessment of the outcomes of surgical treatment of patients with metastatic spinal cord injuries

Every year the number of cancer patients increases due to increased life expectancy. According to various sources, metastases in the spine are found during autopsy in 30-90% of patients with a history of cancer. So far, there have been no full-scale studies of the quality of life of patients with various metastatic tumors of the spine who underwent surgical treatment in Russian literature. The main objective of this study was to demonstrate the need for implementing the comprehensive treatment of patients with metastases in the spine and target setting as the main tool to identify the factors that adversely affect the patients' quality of life. The quality of life of 56 patients aged 16 to 81 years was assessed, including 26 males and 30 females. Twenty-six patients underwent surgical treatment between 2002 and 2009, and thirty patients underwent surgical treatment between 2009 and 2014. Kidney cancer was a primary disease in 30.3% of patients, multiple myeloma was a primary disease in 23.1% of cases, and the primary source of a tumor was not identified in cancer screening in 10.5% of cases. There were also isolated cases of melanoma, thymoma, metastases of tumors of the gastrointestinal tract, uterus, ovary, lung, prostate, pancreas, and the thyroid gland, which on the average amounted to 3.5% (1.8 to 7.14%). The quality of life of patients was studied using the EORTC QLQ C30 scale. The patients were surveyed prior to the surgery and then 1, 3, 6 and 12 months after surgical treatment during 1 year or until death. Preoperative and postoperative contrast-enhanced SCT and MRI examinations were used to control the extent of decompression of neural structures. On the basis of these findings, the authors identified the main factors affecting the quality of life of patients and formulated a range of treatment goals for patients with metastases in the spine. Surgical treatment has a positive effect on the quality of life of patients with metastases in the spine. However, it is not a key factor in the context of survival rate of these patients. Therefore, a decision on the possibility and necessity of surgical treatment should be taken in cooperation with the patient and oncologists of different specialties.