Magnetic Resonance Imaging Enhancement Patterns Research Articles

Predicting cerebral glioma enhancement pattern using a machine learning-based magnetic resonance imaging radiomics model

To establish a machine learning radiomics model that can accurately predict MRI enhancement patterns of glioma based on T2 fluid attenuated inversion recovery (T2-FLAIR) images for optimizing the workflow of magnetic resonance imaging (MRI) examinations of glioma patients. We retrospectively collected preoperative MR T2-FLAIR images from 385 patients with pathologically confirmed glioma, who were divided into enhancing and non-enhancing groups according to the enhancement pattern. Predictive radiomics models were established using Gaussian Process, Linear Regression, Linear Regression-Least absolute shrinkage and selection operator, Support Vector Machine, Linear Discriminant Analysis or Naive Bayes as the classifiers in the training cohort (n=201)and tested both in the internal (n=85) and external validation cohorts (n=99). The receiver-operating characteristic curve was used to assess the predictive performance of the models. The predictive model constructed based on 15 radiomics features using Gaussian Process as the classifier had the best predictive performance in both the training cohort and the internal validation cohort, with areas under the curve (AUC) of 0.88 (95% CI: 0.81-0.94) and 0.80 (95% CI: 0.71-0.88), respectively. In the external validation cohort, the model showed an AUC of 0.81 (95% CI: 0.71-0.90) with sensitivity, specificity, positive predictive value and negative predictive value of 0.98, 0.61, 0.76 and 0.96, respectively. The T2-FLAIR-based machine learning radiomics model can accurately predict the enhancement pattern of gliomas on MRI.

Manganese (II) Complex of 1,4,7-Triazacyclononane-1,4,7-Triacetic Acid (NOTA) as a Hepatobiliary MRI Contrast Agent.

Magnetic resonance imaging (MRI) is increasingly used to diagnose focal and diffuse liver disorders. Despite their enhanced efficacy, liver-targeted gadolinium-based contrast agents (GBCAs) raise safety concerns owing to the release of toxic Gd3+ ions. A π-conjugated macrocyclic chelate, Mn-NOTA-NP, was designed and synthesized as a non-gadolinium alternative for liver-specific MRI. Mn-NOTA-NP exhibits an r1 relaxivity of 3.57 mM-1 s-1 in water and 9.01 mM-1 s-1 in saline containing human serum albumin at 3 T, which is significantly greater than the clinically utilized Mn2+-based hepatobiliary drug, Mn-DPDP (1.50 mM-1 s-1), and comparable with that of GBCAs. Furthermore, the in vivo biodistribution and MRI enhancement patterns of Mn-NOTA-NP were similar to those of the Gd3+-based hepatobiliary agent, Gd-DTPA-EOB. Additionally, a 0.05 mmol/kg dose of Mn-NOTA-NP facilitated high-sensitivity tumor detection with tumor signal enhancement in a liver tumor model. Ligand-docking simulations further indicated that Mn-NOTA-NP differed from other hepatobiliary agents in their interactions with several transporter systems. Collectively, we demonstrated that Mn-NOTA-NP could be a new liver-specific MRI contrast agent.

MRI Appearance of Focal Lesions in Liver Iron Overload.

Liver iron overload is defined as an accumulation of the chemical element Fe in the hepatic parenchyma that exceeds the normal storage. When iron accumulates, it can be toxic for the liver by producing inflammation and cell damage. This can potentially lead to cirrhosis and hepatocellular carcinoma, as well as to other liver lesions depending on the underlying condition associated to liver iron overload. The correct assessment of liver iron storage is pivotal to drive the best treatment and prevent complication. Nowadays, magnetic resonance imaging (MRI) is the best non-invasive modality to detect and quantify liver iron overload. However, due to its superparamagnetic properties, iron provides a natural source of contrast enhancement that can make challenging the differential diagnosis between different focal liver lesions (FLLs). To date, a fully comprehensive description of MRI features of liver lesions commonly found in iron-overloaded liver is lacking in the literature. Through an extensive review of the published literature, we aim to summarize the MRI signal intensity and enhancement pattern of the most common FLLs that can occur in liver iron overload.

Abdominal perivascular epithelioid cell tumor (PEComa) without visible fat: a clinicopathologic and radiological analysis of 16 cases.

To retrospectively review the clinicopathological features and computed tomography (CT) and magnetic resonance imaging (MRI) findings of abdominal perivascular epithelioid cell tumor without visible fat (PEComawvf). Sixteen patients with surgically and pathologically confirmed perivascular epithelioid cell tumor without visible fat were enrolled. Their clinicopathological data and imaging findings were retrospectively reviewed. The CT and MRI features, including location, size, shape, margin, density, calcification, cystic necrosis and enhancement pattern, were analyzed. There were 4 males and 12 females (median age, 46years; range, 21-65years) in this study. All 16 patients were diagnostic asymptomatic unenhanced CT or MRI and revealed a well-defined (n = 13), oval (n = 10), mass with heterogeneous (n = 6) or homogeneous density/signal intensity (n = 7), calcification and hemorrhage was no found in any cases. On enhanced CT/MRI, markedly enhancement patterns (n = 14) were observed. The "peripheral enhancement" sign was observed in 13 cases. One in 16 cases recurrence was discovered during the follow-up period. Dynamic CT, MRI and pathology of PEComawvf had some characteristics of non-aggressive pattern of performance, and MRI would provide beneficial detection of microscopic fat. Enhanced imaging showed PEComawvf is characterized by a "peripheral enhancement" with a marked enhancement pattern. Knowing these characteristics could contribute to improving the understanding abdominal PEComawvf and related palliative care.

Synthesis and Evaluation of Manganese(II)-Based Ethylenediaminetetraacetic Acid-Ethoxybenzyl Conjugate as a Highly Stable Hepatobiliary Magnetic Resonance Imaging Contrast Agent.

In this study, we designed and synthesized a highly stable manganese (Mn2+)-based hepatobiliary complex by tethering an ethoxybenzyl (EOB) moiety with an ethylenediaminetetraacetic acid (EDTA) coordination cage as an alternative to the well-established hepatobiliary gadolinium (Gd3+) chelates and evaluated its usage as a T1 hepatobiliary magnetic resonance imaging (MRI) contrast agent (CA). This new complex exhibits higher r1 relaxivity (2.3 mM-1 s-1) than clinically approved Mn2+-based hepatobiliary complex Mn-DPDP (1.6 mM-1 s-1) at 1.5 T. Mn-EDTA-EOB shows much higher kinetic inertness than that of clinically approved Gd3+-based hepatobiliary MRI CAs, such as Gd-DTPA-EOB and Gd-BOPTA. In addition, in vivo biodistribution and MRI enhancement patterns of this new Mn2+ chelate are comparable to those of Gd3+-based hepatobiliary MRI CAs. The diagnostic efficacy of the new complex was demonstrated by its enhanced tumor detection sensitivity in a liver cancer model using in vivo MRI.

Differential Diagnosis of Pulmonary Artery Sarcoma and Central Chronic Pulmonary Thromboembolism Using CT and MR Images

Clinical and imaging manifestations are similar in pulmonary artery sarcomas (PAS) and thromboembolic diseases, especially central chronic pulmonary thromboembolism (CPTE). The feasibility of utilising clinical imaging tools such as computed tomography (CT) and magnetic resonance imaging (MRI) for differential diagnosis of PAS and CPTE has not been fully explored, especially MRI. Patients with PAS (n=18) and central CPTE (n=20) treated at our hospital between January 2013 and September 2016 were identified retrospectively. Computed tomography and MRI findings of pulmonary artery (PA) filling defects including the location, the involvement of pulmonary artery, morphology, signal intensities and enhancement in MRI, calcification, sizes of right atrium and ventricle, inner diameters of the pulmonary artery trunk and branches, and mediastinal collateral circulation in both groups were examined, and differences were analysed by Fisher exact test and independent sample t-test. Compared to those of central CPTE, PAS lesions were in full shape or expansive growth (p<0.001), and the proximal end of the tumours was often bulging or lobulated (p<0.001). These lesions were aneurysm- or grape-like distally (p<0.01) with inhomogeneous enhancement (p<0.001). The MRI contrast enhancement pattern of PAS lesions were cloudy with inhomogeneous delayed enhancement and the time-density curves for some of the lesions increased gradually. Computed tomographic and MR imaging manifestations may resemble PAS and central CPTE; however, some manifestations still have great value for the differential diagnosis of these two conditions, specifically the morphology and MRI enhancement patterns.

Contrast-enhanced MRI of the temporomandibular joint: findings in children without juvenile idiopathic arthritis.

Contrast-enhanced magnetic resonance imaging (MRI) is highly sensitive for assessing temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA), but only sparse data exist on normal TMJ appearance in children. To determine normal MRI appearance and enhancement pattern of pediatric TMJ as basis for diagnosing early arthritis. In 27 children (age range, 1.2-16.8 years) without TMJ pathology undergoing head MRI, fat-saturated T2-weighted (T2W) and postcontrast fat-saturated T1-weighted (T1W) images sagittally aligned to the 54 TMJs, besides standard T1W and T2W images, were assessed for bony and soft tissue signal intensity (SI), the amount of perceptible joint fluid, and contrast enhancement (CE). Bone marrow SI and CE of the mandible were consistent with varying degrees of residual red marrow in 96% of joints. The mandibular condyles were mostly isointense to the ramus, but in 9% showed mild edema-like bone marrow SI and CE. Small amounts of intraarticular fluid were detected in 31% on T2W images without fat saturation and in 83% on T2W images with fat saturation as fine lines in the upper or lower joint compartment or as small dots in an articular recess. Seventy-nine percent of all TMJs showed intense joint enhancement on early images restricted to areas of intraarticular fluid. Small amounts of joint fluid with intense CE are a common MRI finding in TMJs of children without JIA and therefore should not be considered diagnostic for early arthritis.

Magnetic resonance imaging evaluation of residual tumors in breast cancer after neoadjuvant chemotherapy: surgical implications.

Magnetic resonance imaging (MRI) can be used to guide breast cancer surgery with breast conservation for large tumors with a substantially reduced size after neoadjuvant chemotherapy (NAC). To evaluate the value of dynamic contrast-enhanced MRI (DCE-MRI) for measuring residual tumor size and enhancement patterns following preoperative NAC. Eighty-nine patients with breast cancer underwent breast DCE-MRI; 38 patients (39 lesions) were treated with NAC and examined for residual disease following therapy. Two patients were excluded because surgery had been performed >2 weeks after the final MR examination. Thus, we correlated the DCE-MRI results of 36 patients (37 lesions) with postoperative histopathological findings. Residual disease was confirmed by more enhancement compared to normal glandular tissue at the initial tumor site. Residual tumor size on DCE-MRI was compared with postoperative pathology findings. Tumor enhancement patterns on DCE-MRI were analyzed and correlated with pathological classification. MRI revealed 34 cases of residual tumors, with two false positives and one false negative. Pathological and MR measurements were correlated (r = 0.793). The correlation of mass enhancement size (r = 0.87, n = 14) with pathology and DCE-MRI was higher than for non-mass-like enhancement (NME) (r = 0.735, n = 23). The distribution of pathologic classification was significantly different between different MRI enhancement patterns (P = 0.006). Mass enhancement had higher cellularity than NME. MRI is useful for evaluating residual carcinoma following NAC. Mass enhancement with higher cellularity after NAC can be evaluated more accurately, which is suitable for evaluating lumpectomy. However, other approaches are required for NME, which has lower cellularity.

MR Enterographic Manifestations of Small Bowel Crohn Disease

Magnetic resonance (MR) enterography is a clinically useful technique for the evaluation of both intraluminal and extraluminal small bowel disease, particularly in younger patients with Crohn disease. MR enterography offers the advantages of multiplanar capability and lack of ionizing radiation. It allows evaluation of bowel wall contrast enhancement, wall thickening, and edema, findings useful for the assessment of Crohn disease activity. MR enterography can also depict other pathologic findings such as lymphadenopathy, fistula and sinus formation, abscesses, and abnormal fold patterns. Even subtle disease manifestations may be detected when adequate distention of the small bowel is achieved, although endoscopic and double-contrast barium small bowel techniques remain superior in the depiction of changes in early Crohn disease (eg, aphthoid ulceration). Further research will be needed to determine whether MR imaging enhancement patterns may reliably help discriminate between active and inactive disease.

Late enhancement in cardiac amyloidosis: correlation of MRI enhancement pattern with histopathological findings

Late enhancement (LE) in cardiac magnetic resonance imaging (MRI) is a characteristic finding in patients with cardiac amyloidosis (CA) but the histomorphological explanation has not been clarified yet. Five patients with CA were evaluated by MRI prior to heart transplantation. This consisted of morphological, volumetric, and functional data, including LE analysis. For LE analysis, left ventricular (LV) short-axis sections from basal, midventricular, and apical positions were divided into 12 segments resulting in a 36-segment model. Each segment was differentiated by subendocardial, midmural, and subepicardial localization. Histological amyloid and collagenous fiber deposition was correlated with LE in corresponding MRI slides. LE was visualized in 103/180 (57.2%) predominantly subendocardial segments. Histological analysis of amyloid deposition was (peri-)vascular (n = 5), diffuse interstitial (n = 3) and/or nodular (n = 4). Extent of fibrosis was moderate to severe. Cytoplasmatic vacuolization and decline of myofibrils was seen in all patients. Fibrosis was significantly associated with LE in subendocardial and midmural localizations (p<0.05), whereas the extent of amyloid deposition was not associated with LE findings in any region. LE seems to be associated with fibrosis due to ischemia of cardiomyocytes by small vessel amyloid deposition rather than with amyloid deposition in CA, suggesting that amyloid deposition might be present prior to LE detection.

BI-RADS MRI Enhancement Characteristics of Ductal Carcinoma In Situ

To identify the Breast Imaging Reporting and Data System magnetic resonance imaging (MRI) enhancement characteristics of ductal carcinoma in situ (DCIS). A retrospective review of consecutive patients who underwent breast MRI for newly diagnosed breast carcinoma prior to surgery was conducted. This yielded 381 lesions in 361 patients with pathologic confirmation of either DCIS alone, invasive carcinoma alone, or mixed invasive and in-situ disease. Presence or absence of a MRI lesion at the site of the documented carcinoma was recorded, and for all identified MRI lesions the Breast Imaging Reporting and Data System morphology patterns were recorded. MRI features of the different malignancy types were compared utilizing Fisher's exact tests; 64/381 (16.8%) lesions had DCIS, 101/381 (26.5%) had invasive carcinoma, and 216/381 (56.7%) had mixed invasive/in situ carcinoma. A MRI lesion corresponding to the known cancer was identified in 55/64 (85.9%) cases of DCIS, 98/101 (97.0%) cases of invasive carcinoma, and 212/216 (98.1%) cases of mixed invasive and in-situ carcinoma. For pure DCIS lesions, 38/64 (59.4%) exhibited nonmass-like enhancement (NMLE), 9/64 (14.1%) were masses, and 8/64 (12.5%) were a focus. For pure invasive carcinomas 79/101(78.2%) were masses, 16/101 (15.8%) were NMLE, and 3/101 (3.0%) were a focus. For mixed lesions 163/216 (75.5%) were masses, 44/216 (20.4%) demonstrated NMLE, and 5/216 (2.3%) were a focus. The most common NMLE patterns of pure DCIS were segmental distribution and clumped internal enhancement. Although there is overlap in the MRI morphology and enhancement pattern of in situ and invasive breast carcinoma, DCIS more frequently manifests as NMLE than does invasive carcinoma.

Magnetic Resonance Imaging Captures the Biology of Ductal Carcinoma In Situ

Magnetic resonance imaging (MRI) is an important tool for characterizing invasive breast cancer but has proven to be more challenging in the setting of ductal carcinoma in situ (DCIS). We investigated whether MRI features of DCIS reflect differences in biology and pathology. Forty five of 100 patients with biopsy-proven DCIS who underwent MRI and had sufficient tissue to be characterized by pathologic (nuclear grade, presence of comedo necrosis, size, and density of disease) and immunohistochemical (IHC) findings (proliferation, Ki67; angiogenesis, CD34; and inflammation, CD68). Pathology and MRI features (enhancement patterns, distribution, size, and density) were analyzed using pairwise and canonical correlations. Histopathologic and IHC variables correlated with MRI features (r = 0.73). The correlation was largely due to size, density (by either MRI or pathology), and inflammation (P < .05). Most small focal masses were estrogen receptor-positive. MRI enhancement patterns that were clumped were more likely than heterogeneous patterns to be high-grade lesions. Homogenous lesions were large, high grade, and rich in macrophages. Presence of comedo necrosis and size could be distinguished on MRI (P < .05). MRI was most likely to over-represent the size of less dense, diffuse DCIS lesions. The heterogeneous presentation of DCIS on MRI reflects underlying histopathologic differences.

Dynamic magnetic resonance imaging enhancement patterns of the bowel wall correlate with clinical and inflammatory activity in Crohn's disease

Dynamic magnetic resonance imaging enhancement patterns of the bowel wall correlate with clinical and inflammatory activity in Crohn's disease

Gadolinium-enhanced Magnetic Resonance Imaging Assessment of Hydroxyapatite Orbital Implants

Spirnak, J. P.; Nieves, N.; Hollsten, D. A.; White, W. C.; Betz, T. A. Author Information

Invasive breast carcinoma: Analysis of dynamic magnetic resonance imaging enhancement features and cell proliferative activity determined by DNA S‐phase percentage

BACKGROUND There is little information regarding associations between magnetic resonance imaging (MRI) enhancement and biologic parameters of breast carcinoma. A prospective study was undertaken to correlate MRI dynamic contrast enhancement features with cell proliferative activity, as determined by DNA S-phase percentage. METHODS Seventeen patients with invasive breast carcinoma underwent MRI at 1.5 tesla using a dynamic gadolinium-enhanced spoiled gradient recall echo technique. DNA analysis of samples of the excised lesions was then performed using flow cytometry. RESULTS Invasive carcinomas with high DNA S-phase percentages (;ce6.9%, the median value in this study), a measure of increased cell proliferation, were associated with a peripheral MRI enhancement pattern in 4 of 6 (67%) lesions compared with 0 of 11 carcinomas with lower DNA S-phase percentages (;cc6.9%) (P = 0.006). There was no significant association between a high DNA S-phase percentage and greater MRI enhancement amplitude, rate, or washout. There was no significant association between aneuploid DNA content and any MRI enhancement feature. CONCLUSIONS Increased cell proliferation in invasive breast carcinoma, as determined by high DNA S-phase percentage, is significantly associated with a peripheral MRI enhancement pattern but unrelated to greater MRI enhancement amplitude, rate, or washout. Cancer 1996;77:1844-9.

Nonneoplastic chorioretinal enhancement patterns in magnetic resonance imaging of the eye : Hardjasudarma M, Ganley JP, McClellan RL, et al. (Department of Radiology, School of Medicine in Shreveport, Louisiana State University Medical Center, P.O. Box 33932, Shreveport, LA 71130-3932, USA). Can Assoc Radiol J 1995;46:183–188

To define the role of contrast-enhanced magnetic resonance imaging (MRI) as a possible adjunct to funduscopy and ultrasonography in a selected sample of non-neoplastic disorders of the chorioretina.The study group consisted of five patients (ranging in age from 3 to 78 years) with one of the following diagnoses: ocular toxocariasis, staphyloma, glaucoma, or ocular involvement of cytomegalovirus (CMV) infection or AIDS. All of the patients underwent MRI, and the findings were correlated with those of funduscopy and ultrasonography when possible.There were two abnormal MRI enhancement patterns, one with and the other without major distortion of the chorioretina. Areas of abnormal enhancement correlated well with the funduscopic findings. For the patient with CMV infection and the one with AIDS, who were not examined with ultrasonography, MRI showed subtle chorioretinal abnormalities. In the other three cases, for which both ultrasonography and MRI were performed, the findings of the two methods correlated well.Ultrasonography remains the imaging modality of choice in the work-up of most ocular abnormalities. Ultrasonography, MRI and computed tomography are recommended when funduscopy is technically not possible. Because contrast-enhanced MRI is often performed to define the remainder of the orbit, as well as extra-orbital structures, and because of its capability to demonstrate abnormalities of the chorioretina, this modality may serve as a useful adjunct to ultrasonography. Further studies are needed to compare the efficacy of contrast-enhanced MRI and ultrasonography in the evaluation of small, nonneoplastic lesions of the chorioretina.

Gadolinium-enhanced Magnetic Resonance Imaging Assessment of Hydroxyapatite Orbital Implants

Successful prosthesis attachment depends on complete vascularization of porous coralline hydroxyapatite when it is used as an orbital implant. We retrospectively assessed the utility of gadolinium-enhanced magnetic resonance imaging to evaluate and characterize the temporal progression of this fibrovascular process, which has been histologically documented elsewhere. Serial T1-weighted gadolinium-enhanced orbital magnetic resonance examinations were performed in five patients receiving hydroxyapatite orbital implants. Retrospective evaluation of the enhancement patterns was performed. Magnetic resonance imaging enhancement patterns guided timing of final drilling for prosthesis fixation. Serial gadolinium-enhanced T1-weighted sequences consistently demonstrated centrally advancing, peripheral enhancement centered on the drilled access channels. Progression over time varied, with the following two patterns demonstrated: (1) rapid peripheral enhancement, which led to diffuse enhancement (three patients); and (2) enhancement limited to the periphery, which failed to advance centrally. The temporal enhancement seen on magnetic resonance imaging is identical to the histologically proven fibrovascular ingrowth pattern and most likely reflects this process. Magnetic resonance imaging can identify progression of fibrovascular ingrowth into the hydroxyapatite orbital implants and guide surgical planning. It may also identify implants that fail to vascularize, thereby preventing the morbidity encountered by drilling into an avascular hydroxyapatite implant.

Ferrioxamine B derivatives as hepatobiliary contrast agents for magnetic resonance imaging

Succinyl (SDF), phenylsuccinyl (PSDF), glutaryl (GDF), and phenylglutaryl (PGDF) derivatives of desferrioxamine B (DF) have been synthesized. In rats given the 59Fe(III) chelates of each these ligands at tracer levels, 82-94% of the 59Fe was eliminated within 1-2 days. 59Fe given as DF, SDF, and GDF chelates was excreted primarily in the urine, while nearly 50% of that given as PSDF and PGDF was excreted in the feces. Correspondingly, Fe-DF, Fe-SDF, and Fe-GDF (0.2 mmol/kg) produced early, marked renal, but no gastrointestinal magnetic resonance imaging (MRI) enhancement. Fe-PSDF and Fe-PGDF (0.2 mmol/kg) produced marked and rapid MRI enhancement of the upper small intestine. In animals with cannulated bile ducts, 59Fe from 59Fe-PGDF (carrier added, 0.1 mmol/kg) appeared rapidly in the collected bile, but not in the intestinal contents, proving that the contrast agent reaches the bowel via the bile. These changes in the excretion and MRI enhancement patterns brought about by the presence of a phenyl substituent apparently were not related to changes in lipophilicity or protein binding.