Relative Contrast Enhancement Research Articles

Treatment evaluation by volumetric segmentation in pediatric optic pathway glioma: evaluation of the effect of bevacizumab on intra-tumor components.

Progressive pediatric optic pathway gliomas (OPGs) are treated by diverse systemic antitumor modalities. Refined insights on the course of intra-tumoral components are limited. We performed an exploratory study on the longitudinal volumetric course of different (intra-)tumor components by manual segmentation of MRI at the start and after 3, 6 and 12months of bevacizumab (BVZ) treatment. Thirty-one patients were treated with BVZ (median 12months, range: 2-39months). During treatment the total tumor volume decreased with median 19.9% (range: -62.3 to + 29.7%; n = 30) within the first 3 months, decreased 19.0% (range: -68.8 to + 96.1%; n = 28) between start and 6 months and 27.2% (range: -73.4 to + 36.0%; n = 21) between start and 12months. Intra-tumoral cysts were present in 12 OPGs, all showed a decrease of volume during treatment. The relative contrast enhanced volume of NF1 associated OPG (n = 11) showed an significant reduction compared to OPG with a KIAA1549-BRAF fusion (p < 0.01). Three OPGs progressed during treatment, but were not preceded by an increase of relative contrast enhancement. Treatment with BVZ of progressive pediatric OPGs leads to a decrease of both total tumor volume and cystic volume for the majority of OPGs with emphasis on the first three months. NF1 and KIAA1549-BRAF fusion related OPGs showed a different (early) treatment effect regarding the tumor enhancing component on MRI, which did not correlate with tumor volume changes. Future research is necessary to further evaluate these findings and its relevance to clinical outcome parameters.

P456 Magnetic resonance enterography findings at week 46 after biological treatment predict long-term clinical outcomes in Crohn’s disease patients

Abstract Background Magnetic resonance enterography (MRE) provides an accurate evaluation of transmural lesions in Crohn’s Disease (CD). However, MRE findings associated with poor long-term outcomes in CD are not yet defined. Identification of such parameters would help in defining therapeutic goals. AIMS to identify predictors of long-term clinical outcomes based on MRE findings performed 46 weeks after biological treatment initiation in patients with CD. Methods single-center, prospective, longitudinal study conducted from 2010 to 2019. Patients with CD who had an MRE evaluation 46 weeks after biological treatment initiation and clinical follow-up of at least 3 years were evaluated. Results 89 patients were included with a median follow up of 53 months (IQR 44-76). 59 patients had ileal (66.3%), 26 ileocolic (29.2%) and 4 colonic disease (4.5%). 31 (34.8%) had inflammatory behavior, 27 (30.3%) stricturing, 9 (10.1%) fistulizing and 22 (34.7%) stricturing/fistulizing. 70 (78.7%) were treated with anti-TNFα, 5 (5.6%) vedolizumab and 14 (15.7%) ustekinumab. During follow-up, 25 (28.1%) required surgery, 17 (19.1%) hospitalization, 40 (44.9%) had clinical relapse (CDAI &amp;gt;150), 12 (13.5%) required corticosteroids and 12 (13.5%) required endoscopic dilatation. 32 (36.0%) patients needed resection surgery or endoscopic dilatation. MaRIA score ≥11 in any segment at week 46 was associated with a higher risk of surgery [HR 6.28 (1.42-27.84), p=0,02] or surgery/endoscopic dilatation [HR 3.76 (1.24-11.38), p=0,02]. Relative contrast enhancement (RCE) &amp;gt;103 was associated with higher risk of clinical relapse [HR 1,01 (1.00-1.02), p=0,03] and corticosteroids requirement [HR 1,01 (1.00-1.02), p=0,05]. Conclusion MRE findings at week 46 after biological treatment initiation predict long-term clinical outcomes in CD patients. The main determinants of poor clinical prognosis were MaRIA score ≥11 and RCE &amp;gt;103. Patients with these persistent findings may be candidates for treatment optimization.

P201 Assessment of factors associated with cumulative bowel damage in surgically naïve patients using Lemann index and global MaRIA index in Crohn’s disease

Abstract Background The Lémann index (LI) is a unique tool that measures cumulative bowel damage in Crohn’s disease (CD) and is composed of surgical procedures and severity and extent of bowel lesions according to endoscopy and MR enterography (MRE). Since there is a significant contribution of previous surgery in LI calculation, our aim of this study is to investigate factors associated with cumulative bowel damage using LI in both total population and surgically naïve patients. Methods In this cross-sectional study, LI was calculated evaluating 20 small bowel, 7 large bowel and 3 upper GI segments. For each segment bowel resections, inflammatory, stricturing or penetrating lesions were considered using MRE and upper and lower endoscopy. Global MaRIA (gMaRIA) index was calculated using following parameters on 6 bowel segments on MRE: bowel wall thickness, ulcers, edema, and relative contrast enhancement. Longstanding disease was ≥10-year duration. Disease activity was defined as CRP&amp;gt;5 or HBI≥5. Extent and disease behavior were assessed using Montreal classification. Multivariate logistic regression adjusted for confounders was performed (age, gender, BMI, smoking status, CRP, disease behavior and extension, biological therapy, gMaRIA score, and HBI). Results This study included 320 CD patients [age 36 (24-46), 54.6% males, disease duration 7.2 (1-14) years, BMI 21.3 (17.4-24.8) kg/m2]. There were 142 (44.4%) surgically naïve and 128 (40%) patients with longstanding disease. In total population, higher LI values were observed among those with longstanding disease (10.31 vs 5.35 years, p&amp;lt;0.001), patients treated with biological therapy (9.7 vs. 6.4, p=0.005) and prior surgery (11.81 vs. 1.62, p&amp;lt;0.005). There was no difference in LI according to activity (p=0.921) and smoking status (p=0.336). Multivariate analysis on total population revealed independent predictors of elevated LI which were BMI (β=-0.268, p&amp;lt;0.02), disease duration (β=0.120, p=0.041) and prior surgery (β=5.42, p&amp;lt;0.001). Hence, separate multivariate analysis was performed on surgically naïve which revealed following predictors of LI (other than surgery): current smoking (β=1.14, p=0.010), perianal disease (β=1.39, p=0.02) and gMaRIA score (β=0.093, p&amp;lt;0.001). Conclusion Positive predictors of cumulative bowel damage in surgically naïve patients were smoking, perianal disease, and radiological activity (gMaRIA), while in total population longer disease duration, BMI and prior surgery. There are several important contributing variables on cumulative bowel damage which were revealed after removing previously operated patients, which would otherwise remain unrecognized. This risk factors in CD could stratify patients at high risk for complicated course of disease.

Dual-source computed tomography protocols for the pediatric chest - scan optimization techniques.

The gold standard for pediatric chest imaging remains the CT scan. An ideal pediatric chest CT has the lowest radiation dose with the least motion degradation possible in a diagnostic scan. Because of the known inherent risks and costs of anesthesia, non-sedate options are preferred. Dual-source CTs are currently the fastest, lowest-dose CT scanners available, utilizing an ultra-high-pitch mode resulting in sub-second CTs. The dual-energy technique, available on dual-source CT scanners, gathers additional information such as pulmonary blood volume and includes relative contrast enhancement and metallic artifact reduction, features that are not available in high-pitch flash mode. In this article we discuss the benefits and tradeoffs of dual-source CT scan modes and tips on image optimization.

Assessing the inflammatory severity of the terminal ileum in Crohn disease using radiomics based on MRI

BackgroundEvaluating inflammatory severity using imaging is essential for Crohn’s disease, but it is limited by potential interobserver variation and subjectivity. We compared the efficiency of magnetic resonance index of activity (MaRIA) collected by radiologists and a radiomics model in assessing the inflammatory severity of terminal ileum (TI).Methods121 patients were collected from two centers. Patients were divided into ulcerative group and mucosal remission group based on the TI Crohn’s disease Endoscopic Severity Index. The consistency of bowel wall thickness (BWT), relative contrast enhancement (RCE), edema, ulcer, MaRIA and features of the region of interest between radiologists were described by weighted Kappa test and intraclass correlation coefficient (ICC), and developed receiver operating curve of MaRIA. The radiomics model was established using reproducible features of logistic regression based on arterial staging of T1WI sequences. Delong test was used to compare radiomics with MaRIA.ResultsThe consistency between radiologists were moderate in BWT (ICC = 0.638), fair in edema (κ = 0.541), RCE (ICC = 0.461), MaRIA (ICC = 0.579) and poor in ulcer (κ = 0.271). Radiomics model was developed by 6 reproducible features (ICC = 0.93–0.96) and equivalent to MaRIA which evaluated by the senior radiologist (0.872 vs 0.883 in training group, 0.824 vs 0.783 in validation group, P = 0.847, 0.471), both of which were significantly higher than MaRIA evaluated by junior radiologist (AUC: 0.621 in training group, 0.557 in validation group, all, P < 0.05).ConclusionThe evaluation of inflammatory severity could be performed by radiomics objectively and reproducibly, and was comparable to MaRIA evaluated by the senior radiologist. Radiomics may be an important method to assist junior radiologists to assess the severity of inflammation objectively and accurately.

Visualization and Quantification of the Extracellular Matrix in Prostate Cancer Using an Elastin Specific Molecular Probe.

Simple SummaryOne of the most commonly diagnosed cancers in men is prostate cancer (PCa). Understanding tumor progression can help diagnose and treat the disease at an early stage. Components of the extracellular matrix (ECM) play a key role in the development and progression of PCa. Elastin is an essential component of the ECM and constantly changes during tumor development. This article visualizes and quantifies elastin in magnetic resonance imaging (MRI) using a small molecule probe. Results were correlated with histological examinations. Using an elastin-specific molecular probe, we were able to make predictions about the cellular structure in relation to elastin and thus draw conclusions about the size of the tumor, with smaller tumors having a higher elastin content than larger tumors.Human prostate cancer (PCa) is a type of malignancy and one of the most frequently diagnosed cancers in men. Elastin is an important component of the extracellular matrix and is involved in the structure and organization of prostate tissue. The present study examined prostate cancer in a xenograft mouse model using an elastin-specific molecular probe for magnetic resonance molecular imaging. Two different tumor sizes (500 mm3 and 1000 mm3) were compared and analyzed by MRI in vivo and histologically and analytically ex vivo. The T1-weighted sequence was used in a clinical 3-T scanner to calculate the relative contrast enhancement before and after probe administration. Our results show that the use of an elastin-specific probe enables better discrimination between tumors and surrounding healthy tissue. Furthermore, specific binding of the probe to elastin fibers was confirmed by histological examination and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). Smaller tumors showed significantly higher signal intensity (p > 0.001), which correlates with the higher proportion of elastin fibers in the histological evaluation than in larger tumors. A strong correlation was seen between relative enhancement (RE) and Elastica–van Gieson staining (R2 = 0.88). RE was related to inductively coupled plasma–mass spectrometry data for Gd and showed a correlation (R2 = 0.78). Thus, molecular MRI could become a novel quantitative tool for the early evaluation and detection of PCa.

P193 Assessement of cumulative bowel damage using Lemann index and MaRIA score in surgically naive patients with Crohn’s disease

Abstract Background The Lémann index (LI) is a unique tool that measures cumulative bowel damage in Crohn’s disease (CD) using data on surgical procedures and severity and extent of bowel lesions. Magnetic resonance index of activity (MaRIA) is composed of features independently associated with endoscopic disease activity. Primary aim was to investigate differences in factors associated with elevated LI in total population and surgically naive patients. Secondary aim was to compare diagnostic accuracy of gMARIA and LI in determing active disease in surgically naive patients. Methods In this cross-sectional study on 251 CD patients LI was calculated evaluating 20 small bowel, 7 large bowel and 3 upper GI segments. For each segment bowel resections, inflammatory, stricturing or penetrating lesions were taken into account. Global MaRIA (gMaRIA) index was calculated using following parameters on 6 bowel segments: bowel wall thickness, ulcers, edema and relative contrast enhancement. Longstanding disease was defined as ≥10 year disease duration. Disease activity was defined as combination of clinical and biochemical disease activity (CRP&amp;gt;5 or HBI≥5). Results This study included 251 CD patients [age 35 (25–47), 55.3% males, disease duration 7 (2–15) years]. There were 103 (40%) surgically naïve and 112 (44.6%) patients with longstanding disease. In total population, higher LI values were observed in patients with longstanding disease (10.47 vs 5.41, p&amp;lt;0.001), patients treated with biological therapy (9.6 vs. 6.3, p=0.005) and with prior surgery (11.92 vs. 1.57, p&amp;lt;0.005). There was no difference in LI according to activity (7.53 vs. 7.66, p=0.911) and smoking status (6.9 vs. 7.3, p=0.336). In multivariate analysis adjusted for age, gender and BMI, independent predictors of elevated LI in total population was prior surgery (β=9.26, p&amp;lt;0.001) and disease duration (β=0.20, p&amp;lt;0.003). Independent predictors in surgically naive patients were current or ex smoking status (β=1.69, p&amp;lt;0.001) and gMARIA (β=0.10, p&amp;lt;0.001). Biological therapy, disease duration and clinical and biochemical disease activity were not significant predictors (p&amp;gt;0.05). Diagnostic accuracy of LI in surgically naive patients in defining active disease was lower [AUC 0.75 (95%CI 0.65–0.84)] compared to gMaRIA [AUC 0.82 (95%CI 0.73–0.89)]. Conclusion Since surgical procedures contribute significantly to the LI, it is important to determine predictors of cumulative bowel damage in surgically naive patients. CD patients should be strongly advised to stop smoking and to regularly monitor disease activity using radiological methods. gMaRIA is superior to LI in detecting active disease in surgically naive patients.

P212 Assessment of Crohn’s disease activity using global MaRIA score in patients with ileal and ileocolonic disease

Abstract Background Magnetic resonance index of activity (MaRIA) is composed of features independently associated with endoscopic disease activity and is surrogate marker of disease activity. The aim of this study was to evaluate correlation of global MaRIA (gMaRIA) with clinical and biochemical disease activity indices and diagnostic accuracy for active disease in patients with terminal ileum disease and ileocolonic disease. Methods This is a cross-sectional study which included 251 patients with diagnosed CD. Global MaRIA (gMaRIA) index was calculated on 6 bowel segments (the distal ileum, ascending, transverse, descending, sigmoid colon and rectum) using following parameters: bowel wall thickness, ulcers, edema and relative contrast enhancement. Disease activity was defined as combination of clinical and biochemical disease activity (CRP&amp;gt;5 or HBI≥5). Disease extension was classified using Montreal classification (L1 ileum, L2 colon, L3 ileum and colon). Results This study included 251 CD patients [age 35 (25–47), 55.3% males, BMI 21.8 (18–25) kg/m2, median disease duration 7 (2–15) years]. Ileal disease (L1) was present in 84 (33.5%) and ileocolonic disease (L3) in 151 (60.1%) patients. Correlation of gMARIA with biochemical indices of disease activity (CRP) was r=0.48, p&amp;lt;0.001 and with HBI r=0.33, p&amp;lt;0.001. Diagnostic accuracy of gMARIA in defining active disease in patients with L1 disease was considerably high [AUC 0.83 (95%CI 0.72–0.91)]. On the other hand, diagnostic accuracy in defining active disease in patients with L3 disease was good [AUC 0.71 (95%CI 0.62–0.79)], which is lower compared to L1 disease. In surgically naïve patients diagnostic accuracy of L1 disease was [AUC 0.88 (95%CI 0.72–0.96)], and for L3 disease [AUC 0.78 (95%CI 0.64–0.89)]. Conclusion Global MaRIA index showed higher diagnostic accuracy in detecting clinically and biochemically active disease in terminal ileum compared to ileocolic disease. These results emphasize the important role of magnetic resonance enterography in monitoring disease activity in patients with isolated ileal disease. Global MaRIA score correlates better with biochemical disease activity compared to clinical disease activity, which points out to the significance of biochemical remission.

Utility of multiparametric pre-operative magnetic resonance imaging in differentiation of chordoid meningioma from the other histopathological subtypes of meningioma-a retrospective study.

To determine the magnetic resonance imaging (MRI) features which could pre-operatively differentiate chordoid meningioma (CM) from other histopathological subtypes of meningioma. Retrospective analysis of pre-operative MRI of cases with histopathologically confirmed diagnosis of meningioma during the last 5 years at our institute was done. T1W, T2W, FLAIR sequences, and post-contrast enhancement were evaluated on a qualitative scale. Normalized ADC ratios (nADCR) and normalized fractional anisotropy ratios (nFAR) were derived. The intratumoral susceptibility score (ITSS), presence of sunburst pattern of vasculature, bone changes, tumour-parenchyma interface, and oedema-to-tumour ratio were also determined. A total of 81 lesions were analyzed out of which 15 were CM. CM showed a higher relative contrast enhancement as compared to all other subtypes except for angiomatous and microcystic meningioma. Relative signal intensity on FLAIR could differentiate CM from transitional meningioma. nFAR was found to be significantly higher in fibroblastic meningioma and significantly lower in microcystic meningiomas as compared to CM. Anaplastic meningiomas were remarkable for bone changes and an ill-defined tumour-brain interface in significantly higher proportion of cases as compared to CM. nADCR > 1.5 was found to be an independent predictor of CM with a sensitivity of 84.6%, specificity of 89.8%, positive predictive value of 64.7%, and negative predictive value of 96.4%. Routine pre-operative MRI may be able to differentiate CM from other meningioma subtypes and a cut-off value of greater than 1.5 for nADCR could be predictive of > 50% chordoid histology of meningioma with a high sensitivity, specificity, and negative predictive value.

Early Transmural Response Assessed Using Magnetic Resonance Imaging Could Predict Sustained Clinical Remission and Prevent Bowel Damage in Patients with Crohn's Disease Treated with Anti-Tumour Necrosis Factor Therapy.

Magnetic resonance imaging [MRI] is a promising tool to evaluate therapeutic efficacy in ileocolonic Crohn's disease [CD]. We aimed to assess the feasibility of early MRI evaluation (week 12 [W12]) to predict corticosteroid-free remission [CFREM] at W52 and prevent long-term bowel damage. All patients with active CD needing anti-tumour necrosis factor [anti-TNF] therapy were consecutively enrolled in this multicentre prospective study. MRI was performed before starting therapy, at W12 and W52. CFREM was defined as Crohn's Disease Activity Index < 150, C-reactive protein < 5 mg/L and faecal calprotectin < 250 µg/g, with no switch of anti-TNF agents, no bowel resection and no therapeutic intensification between W12 and W52. Among 46 patients, 22 [47.8%] achieved CFREM at W52. Anti-TNF agents were able to heal almost all CD lesions as soon as W12 [p < 0.05]. Early transmural response defined as a 25% decrease of either Clermont score (odds ratio [OR] = 7.7 [1.7-34.0], p < 0.001) or Magnetic Resonance Index of Activity (OR = 4.2 [1.3-13.3], p = 0.015) was predictive of CFREM at W52. Achieving at least two items on W12-MRI among ulceration healing, disappearance of enlarged lymph nodes or sclerolipomatosis, ΔADC [apparent diffusion coefficient] > +10% or ΔRCE [relative contrast enhancement] > -30% was associated with a likelihood of CFREM at W52 of 84.6% vs 37.5% in patients without transmural response [p < 0.001]. Early transmural response could prevent bowel damage progression over time using Clermont score (hazard ratio = 0.21 [0.0-0.9]; p = 0.037). Evaluation of early transmural response by MRI is feasible and is a promising end point to monitor therapeutic efficacy in patients with CD.

Metallic nanoparticles as X-Ray computed tomography (CT) contrast agents: A review

X-ray computed tomography vastly used in both medical purposes and in the research of biological and non-biological materials/samples. Some of the medical applications performed in the clinics requires special protocols where contrast agents may be needed to enhance the contrast. Iodine based contrast agents are commonly used in such applications. Iodine based contrast agents were found hazardous to the environment and some patients has iodine in tolerance due to thyroid origin diseases. Scientists from different fields try to develop contrast agents which can be an alternative to iodine based contrast agents. Metallic nanoparticles have potential to be used as CT contrast agent since metals has high X-ray attenuation and high density. Metal nanoparticles considered as toxic to the living organisms. Covering nanoparticles with organic molecule often reduce toxicity and enhance the biocompatibility. Decoration of nanoparticles with function groups give them targeting properties where special organ and/or tissue can be targeted. Up to now, different studies illustrated the importance of the multipurpose properties of the metallic nanoparticles. In this report, we assessed the metal nanoparticles reported as X-ray computed tomography contrast agent. For the first time in the literature we listed in vivo contrast enhancement, targeted drug delivery and dual/multipurpose imaging properties of each metallic nanoparticles. Therapeutic effects of metallic nanoparticles such as photothermal therapy and magnetic hyperthermia were also addressed. A chart showing relative contrast enhancement properties of the nanoparticles were produced.

Signal changes in T2-weighted MRI of liver metastases under bevacizumab-A practical imaging biomarker?

The purpose of this study was to investigate signal changes in T2-weighted magnetic resonance imaging of liver metastases under treatment with and without bevacizumab-containing chemotherapy and to compare these signal changes to tumor contrast enhancement. Retrospective analysis of 44 patients, aged 36-84 years, who underwent liver magnetic resonance imaging including T2-weighted and dynamic contrast enhancement sequences. Patients received bevacizumab-containing (n = 22) or conventional cytotoxic chemotherapy (n = 22). Magnetic resonance imaging was obtained at baseline and at three follow-ups (on average 3, 6 and 9 months after initial treatment). Three independent readers rated the T2 signal intensity and the relative contrast enhancement of the metastases on a 5-point scale. T2 signal intensity of metastases treated with bevacizumab showed a significant (p<0.001) decrease in T2 signal intensity after initial treatment and exhibit compared to conventionally treated metastases significantly (p<0.001 for each follow-up) hypointense (bevacizumab: 0.70 ± 0.83 before vs. -1.55 ± 0.61, -1.91 ± 0.62, and -1.97 ± 0.52; cytotoxic: 0.73 ± 0.79 before vs. -0.69 ± 0.81, -0.71 ± 0.68, and -0.75 ± 0.65 after 3, 6, and 9 months, respectively). T2 signal intensity was strongly correlated with tumor contrast enhancement (r = 0.71; p<0.001). Intra-observer agreement for T2-signal intensity was substantial (κ = 0.75). The agreement for tumoral contrast enhancement between the readers was considerably lower (κ = 0.39). Liver metastases exhibit considerably hypointense in T2-weighted imaging after treatment with bevacizumab, in contrast to conventionally treated liver metastases. Therefore, T2-weighted imaging seems to reflect the effect of bevacizumab.

Evaluation of ileal Crohn’s disease response to TNF antagonists: Validation of MR enterography for assessing response. Initial results

PurposeTo assess the value of MRI obtained before and after treatment in detecting mucosal healing in patients with ileal Crohn’s disease (CD) treated with anti-TNF drugs. MethodsIn this IRB approved retrospective study, 24 patients (M/F 11/13, age 34.0 ± 12.5 years, age range 19–55 years) with ileal CD who underwent anti-TNF treatment, with pre- and post-treatment MRI (mean delay between MRIs 92 ± 57 weeks) were included. All patients underwent routine MR enterography (MRE), which included diffusion-weighted imaging (DWI). Two readers evaluated qualitative features (wall thickness, presence of edema and length of involvement) in consensus and one reader measured the following quantitative variables: relative contrast enhancement (RCE) and apparent diffusion coefficient (ADC) to derive the MaRIA and Clermont scores at baseline, post-treatment and their changes (ΔMaRIA, ΔClermont). Ileocolonoscopy results were used as the reference standard. Data was evaluated using Mann-Whitney U test and receiver operating characteristics analysis to assess the utility of the measures for the detection of mucosal healing. ResultsTwenty-four ileal segments were assessed in 24 patients. Nine patients showed mucosal healing while 15 had no mucosal healing on post-treatment endoscopy. Pre-treatment Clermont score and wall thickness and post-treatment MaRIA and Clermont scores, wall thickness, edema, length of involvement as well as ΔMaRIA and ΔClermont were all significantly different in patients with and without mucosal healing (p-range: 0.001-0.041) while MaRIA pre-treatment and ADC pre- and post-treatment were not. Pre-treatment Clermont score as well as post-treatment MaRIA and Clermont scores, wall thickness and ΔMaRIA were all significantly predictive of detection of mucosal healing (AUC 0.813-0.912; p = 0.003-0.024) after anti-TNF treatment. ConclusionPre-treatment Clermont score as well as post-treatment MaRIA and Clermont scores, wall thickness and ΔMaRIA are significantly predictive of response to anti-TNF drugs in ileal Crohn’s disease. These results need to be verified in a larger study.

Assessment of hepatitis and fibrosis using Gd-EOB-DTPA MRI in dogs

BackgroundGadoxetate sodium (Gd-EOB-DTPA) is taken into hepatocytes and excreted into the bile. Hepatocytes with reduced function or dysfunction due to hepatocellular carcinoma (HCC), hepatitis or hepatic fibrosis show impaired Gd-EOB-DTPA...

Activatable NIRF/MRI dual imaging probe using bio-inspired coating of glycol chitosan on superparamagnetic iron oxide nanoparticles

MRI and NIRF multimodal imaging probe was fabricated and investigated. Glycol chitosan coated SPION was decorated by MMP-2 substrate conjugating BHQ-3 and Cy5.5 dye at each end (BCMG-SPION). NIRF signals were recovered in the presence of MMP-2 at a sub-nanomolar level. BCMG-SPION produced the maximum NIRF intensity at 48 h post injection in vivo. Evaluation of the BCMG-SPION in the tumor tissue by MRI showed that relative contrast enhancement was 34% higher than normal muscles. NIRF images of excised organs showed the highest NIRF signal in tumor and the intensity was at least 8 times higher than other organs.

Association between oncogenic RAS mutation and radiologic-pathologic findings in patients with primary rectal cancer.

To evaluate the association between various radiologic-pathologic findings and oncogenic Kirsten-ras (KRAS) mutation in patients with primary rectal cancer. Seventy-five patients with primary rectal cancer who had undergone rectal magnetic resonance imaging (MRI) were included. The rectal MRI consisted of T2-weighted images in three planes, pre- and post-contrast-enhanced T1-weighted images, and axial diffusion-weighted images (b factors, 0, 1,000 s/mm2). Two radiologists reviewed the MRI scans and measured the axial and longitudinal tumor lengths (LTLs), apparent diffusion coefficient (ADC), and relative contrast enhancement [signal intensity (SI) difference of tumor on pre- and post-contrast T1WI/SI of tumor on pre-contrast T1WI]. The associations among the qualitative data (tumor stage, node stage, lymphatic invasion, venous invasion, and perineural invasion), quantitative data (tumor length, ADC, relative contrast enhancement) and KRAS mutations were statistically analyzed by Fisher's exact test for the qualitative data and by the Mann-Whitney U test for the quantitative data. An area under receiver operating characteristic curve (AUC) was considered as the diagnostic performance for the prediction of KRAS mutation. Molecular-biologic results served as the reference standard. The ratio of axial to LTL in the KRAS-mutant group (n=41) was higher than that in the wild-type group (n=34) (0.29±0.15; 0.22±0.08, P=0.0117). The AUC was 0.640 (95% CI, 0.520 to 0.747, P=0.0292) with an estimated maximum accuracy of 64%. The mean ADC of the mutant group was not significantly different from that of the wild-type group [(0.95±0.17)×10-3 mm2/s; (0.96±0.17)×10-3 mm2/s, P=0.6505]. The relative contrast enhancement showed no significant difference between the two groups (1.66±0.93, 1.35±0.84, P=0.1581). The other qualitative findings also did not show any significant difference (P>0.05). The ratio of axial to LTL showed a significant difference according to KRAS mutation in patients with primary rectal cancer. However, it showed a low accuracy of 64% for prediction of KRAS mutation.

Curved planar reformatting and convolutional neural network-based segmentation of the small bowel for visualization and quantitative assessment of pediatric Crohn's disease from MRI.

Contrast-enhanced MRI of the small bowel is an effective imaging sequence for the detection and characterization of disease burden in pediatric Crohn's disease (CD). However, visualization and quantification of disease burden requires scrolling back and forth through 3D images to follow the anatomy of the bowel, and it can be difficult to fully appreciate the extent of disease. To develop and evaluate a method that offers better visualization and quantitative assessment of CD from MRI. Retrospective. Twenty-three pediatric patients with CD. 1.5T MRI system and T1 -weighted postcontrast VIBE sequence. The convolutional neural network (CNN) segmentation of the bowel's lumen, wall, and background was compared with manual boundary delineation. We assessed the reproducibility and the capability of the extracted markers to differentiate between different levels of disease defined after a consensus review by two experienced radiologists. The segmentation algorithm was assessed using the Dice similarity coefficient (DSC) and boundary distances between the CNN and manual boundary delineations. The capability of the extracted markers to differentiate between different disease levels was determined using a t-test. The reproducibility of the extracted markers was assessed using the mean relative difference (MRD), Pearson correlation, and Bland-Altman analysis. Our CNN exhibited DSCs of 75 ± 18%, 81 ± 8%, and 97 ± 2% for the lumen, wall, and background, respectively. The extracted markers of wall thickness at the location of min radius (P = 0.0013) and the median value of relative contrast enhancement (P = 0.0033) could differentiate active and nonactive disease segments. Other extracted markers could differentiate between segments with strictures and segments without strictures (P < 0.05). The observers' agreement in measuring stricture length was >3 times superior when computed on curved planar reformatting images compared with the conventional scheme. The results of this study show that the newly developed method is efficient for visualization and assessment of CD. 4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1565-1576.

Magnetic resonance imaging and Crohn's disease endoscopic index of severity: Correlations and concordance.

AIMTo examine the correlation between magnetic resonance imaging (MRI) and endoscopic index of severity (CDEIS) in patients with Crohn’s disease (CD).METHODSThis was a retrospective study of 104 patients with CD that were treated at the Ruijin Hospital between March 2015 and May 2016. Among them, 61 patients with active CD were evaluated before/after treatment. MRI and endoscopy were performed within 7 d. CDEIS was evaluated. MRI parameters included MaRIA scores, total relative contrast enhancement (tRCE), arterial RCE (aRCE), portal RCE (pRCE), delay phase RCE (dRCE), and apparent diffusion coefficient. The correlation and concordance between multiple MRI findings and CDEIS changes before and after CD treatment were examined.RESULTSAmong the 104 patients, 61 patients were classified as active CD and 43 patients as inactive CD. Gender, age, disease duration, and disease location were not significantly different between the two groups (all P > 0.05). CRP levels were higher in the active group than in the inactive group (25.12 ± 4.12 vs 5.14 ± 0.98 mg/L, P < 0.001). Before treatment, the correlations between CDEIS and MaRIAs in all patients were r = 0.772 for tRCE, r = 0.754 for aRCE, r = 0.738 for pRCE, and r = 0.712 for dRCE (all MaRIAs, P < 0.001), followed by MRI single indexes. Among the active CD patients, 44 cases were remitted to inactive CD after treatment. The correlations between CDEIS and MaRIAs were r = 0.712 for aRCE, r = 0.705 for tRCE, r = 0.685 for pRCE, and r = 0.634 for dRCE (all MaRIAs, P < 0.001).CONCLUSIONArterial MaRIA should be an indicator for CD follow-up and dynamic assessment. CD treatment assessment was not completely concordant between CDEIS and MRI.

Gadolinium-based relative contrast enhancement in primary sclerosing cholangitis: additional benefit for clinicians?

To evaluate the benefit of extracellular gadolinium-based contrast agent (GBCA) enhanced magnetic resonance imaging (MRI) in addition to conventional non-enhanced T2-weighted imaging (WI) for quantification of inflammatory or fibrotic alterations in the liver parenchyma of patients with primary sclerosing cholangitis (PSC). MRI (3 T) examinations were reviewed retrospectively by two radiologists in 27 PSC patients (age 42.9±15.6 years), and 19 controls. Regions of interest (ROIs) were drawn onto T2 hyperintense and T2 isointense areas and copied to section position matched non-enhanced and delayed-phase contrast-enhanced T1WI. Signal intensities (SI) obtained from ROIs of the multiphase T1WI were used to calculate relative liver enhancement (RLE). The interobserver agreement of RLE and quantified T2 signal was calculated using Bland-Altman analysis. RLE assessed for both T2 hyperintense (RLEhyper) and T2 isointense (RLEiso) areas were compared in patients and controls (RLEhealthy). The interobserver agreement of RLE in affected hyperintense areas (bias -0.77, limits of agreement -51.7 to 50.1) was superior to the quantification of T2 signal only in these areas (bias -3.35, limits of agreement -162.4 to 155.7). The RLEhyper (86.2±9.7%) was higher than the RLEiso (59.8±6.2%, p=0.03) and the RLEhealthy (53.2±2.7%, p=0.002). The mean RLEiso was not significantly different from the RLEhealthy (p=0.3). The extracellular gadolinium-based RLE of T2 hyperintense areas could be a useful add-on for routine follow up MRI in the detection of early inflammatory changes, possibly preceding formation of fibrotic scarring in PSC patients, if validated in larger cohorts.

Faecal calprotectin and magnetic resonance imaging in detecting Crohn's disease endoscopic postoperative recurrence.

AIMTo assess magnetic resonance imaging (MRI) and faecal calprotectin to detect endoscopic postoperative recurrence in patients with Crohn’s disease (CD).METHODSFrom two tertiary centers, all patients with CD who underwent ileocolonic resection were consecutively and prospectively included. All the patients underwent MRI and endoscopy within the first year after surgery or after the restoration of intestinal continuity [median = 6 mo (5.0-9.3)]. The stools were collected the day before the colonoscopy to evaluate faecal calprotectin level. Endoscopic postoperative recurrence (POR) was defined as Rutgeerts’ index ≥ i2b. The MRI was analyzed independently by two radiologists blinded from clinical data.RESULTSApparent diffusion coefficient (ADC) was lower in patients with endoscopic POR compared to those with no recurrence (2.03 ± 0.32 vs 2.27 ± 0.38 × 10-3 mm²/s, P = 0.032). Clermont score (10.4 ± 5.8 vs 7.4 ± 4.5, P = 0.038) and relative contrast enhancement (RCE) (129.4% ± 62.8% vs 76.4% ± 32.6%, P = 0.007) were significantly associated with endoscopic POR contrary to the magnetic resonance index of activity (MaRIA) (7.3 ± 4.5 vs 4.8 ± 3.7; P = 0.15) and MR scoring system (P = 0.056). ADC < 2.35 × 10-3 mm²/s [sensitivity = 0.85, specificity = 0.65, positive predictive value (PPV) = 0.85, negative predictive value (NPV) = 0.65] and RCE > 100% (sensitivity = 0.75, specificity = 0.81, PPV = 0.75, NPV = 0.81) were the best cut-off values to identify endoscopic POR. Clermont score > 6.4 (sensitivity = 0.61, specificity = 0.82, PPV = 0.73, NPV = 0.74), MaRIA > 3.76 (sensitivity = 0.61, specificity = 0.82, PPV = 0.73, NPV = 0.74) and a MR scoring system ≥ MR1 (sensitivity = 0.54, specificity = 0.82, PPV = 0.70, and NPV = 0.70) demonstrated interesting performances to detect endoscopic POR. Faecal calprotectin values were significantly higher in patients with endoscopic POR (114 ± 54.5 μg/g vs 354.8 ± 432.5 μg/g; P = 0.0075). Faecal calprotectin > 100 μg/g demonstrated high performances to detect endoscopic POR (sensitivity = 0.67, specificity = 0.93, PPV = 0.89 and NPV = 0.77).CONCLUSIONFaecal calprotectin and MRI are two reliable tools to detect endoscopic POR in patients with CD.