T2 mapping in patellar chondromalacia

Objective

To study the correlation between the T2 relaxation times of the patellar cartilage and morphological MRI findings of chondromalacia.

Methods

This prospective study comprises 50 patients, 27 men and 23 women suffering of anterior knee pain (mean age: 29.7, SD 8.3 years; range: 16–45 years).MRI of 97 knees were performed in these patients at 1.5 T magnet including sagittal T1, coronal intermediate, axial intermediate fat sat and T2 mapping. Chondromalacia was assessed using a modified version of Noyes classification. The relaxation time, T2, was studied segmenting the full thickness of the patellar cartilage in 12 areas: 4 proximal (external facet–proximal–lateral (EPL), external facet–proximal–central (EPC), internal facet–proximal–central (IPC), internal facet–proximal–medial (IPM), 4 in the middle section (external facet–middle–lateral (EML), external facet–middle–central (EMC), internal facet–middle–central (IMC), internal facet–middle–medial (IMM) and 4 distal (external facet–distal–lateral (EDL), external facet–distal–central (EDC), internal facet–distal–central (IDC), internal facet–distal–medial (IDM).

Results

T2 values showed a significant increase in mild chondromalacia regarding normal cartilage in most of the cartilage areas (p < 0.05), except in the internal distal facet (IDC and IDM), EPC, EDL, and IMM. Severe chondromalacia was characterized by a fall of T2 relaxation times with loss of statistical significant differences in comparison with normal cartilage, except in EMC and IMC, where similar values as mild chondromalacia were maintained (p < 0.05).

Conclusions

Steepest increase in T2 values of patellar cartilage occurs in early stages of patellar cartilage degeneration. Progression of morphologic changes of chondromalacia to more severe degrees is associated to a new drop of T2 relaxation times approaching basal values in most of the areas of the patellar cartilage, except in the central area of the middle section, where T2 values remain increased.     

T2-weighted cardiovascular magnetic resonance imaging

Technical advances in T2-weighted cardiovascular MR (CMR) imaging allow for accurate identification and quantification of tissue injuries that alter myocardial T2 relaxation. Of these, myocardial edema is of special relevance. Increased myocardial water content is an important feature of ischemic as well as nonischemic cardiomyopathies, which are often associated with acute myocardial inflammation. In this article, we review technical considerations and discuss clinical indications of myocardial T2-weighted imaging.     

T2-Weighted Liver MRI Using the MultiVane Technique at 3T: Comparison with Conventional T2-Weighted MRI

Objective

To assess the value of applying MultiVane to liver T2-weighted imaging (T2WI) compared with conventional T2WIs with emphasis on detection of focal liver lesions.

Materials and Methods

Seventy-eight patients (43 men and 35 women) with 86 hepatic lesions and 20 pancreatico-biliary diseases underwent MRI including T2WIs acquired using breath-hold (BH), respiratory-triggered (RT), and MultiVane technique at 3T. Two reviewers evaluated each T2WI with respect to artefacts, organ sharpness, and conspicuity of intrahepatic vessels, hilar duct, and main lesion using five-point scales, and made pairwise comparisons between T2WI sequences for these categories. Diagnostic accuracy (Az) and sensitivity for hepatic lesion detection were evaluated using alternative free-response receiver operating characteristic analysis.

Results

MultiVane T2WI was significantly better than BH-T2WI or RT-T2WI for organ sharpness and conspicuity of intrahepatic vessels and main lesion in both separate reviews and pairwise comparisons (p < 0.001). With regard to motion artefacts, MultiVane T2WI or BH-T2WI was better than RT-T2WI (p < 0.001). Conspicuity of hilar duct was better with BH-T2WI than with MultiVane T2WI (p = 0.030) or RT-T2WI (p < 0.001). For detection of 86 hepatic lesions, sensitivity (mean, 97.7%) of MultiVane T2WI was significantly higher than that of BH-T2WI (mean, 89.5%) (p = 0.008) or RT-T2WI (mean, 84.9%) (p = 0.001).

Conclusion

Applying the MultiVane technique to T2WI of the liver is a promising approach to improving image quality that results in increased detection of focal liver lesions compared with conventional T2WI.     

DWI、T2加权像及综合应用对前列腺癌诊断价值的研究

目的:通过对分别应用T2WI及DWI两种成像方法及其综合应用对前列腺癌进行定性诊断的比较,探讨两种方法各自及综合应用对前列腺癌的诊断价值。方法:应用1.5T MR成像仪对42例前列腺疾病患者进行前列腺磁共振高分辨成像,其中前列腺癌15例,良性病变包括良性前列腺增生及慢性前列腺炎症等27例。在MRI常规成像基础上行DWI扫描,扩散敏感系数(b)值分别为0、1000s/mm2。采用盲法阅片,按照前列腺6分区法将两种MR技术分别所得图像数据分区评估测量并采用5分制评分,根据两种技术的5分制评分进行T2加权像综合DWI方法评分,将所得结果与病理结果对照。利用SPSS 11.5分别做ROC曲线分析比较,计算各组方法诊断的敏感度、特异度及准确度等。结果:各组诊断方法的敏感度、特异度及ROC曲线下面积(Az)如下:T2WI:88.2%,67.2%和0.848±0.030,最佳诊断界值为3;ADC诊断:82.4%,81.6%和0.860±0.033,最佳界值为4;ADC结合T2WI诊断:78.4%,92.5%和0.922±0.021,最佳界值为4.结论:通过独立评估T2WI及DWI两种方法均可以有效诊断前列腺癌;两种成像方法综合应用诊断前列腺癌的准确度显著高于两种成像技术独立诊断,其诊断结果与病理分析一致性较好。     

Incidental high-intensity foci in white matter on T2-weighted magnetic resonance imaging

Summary The clinical significance of high-intensity foci in the white matter on magnetic resonance images of the brain was studied in 351 adults. The foci frequently occurred in the corona radiata and centrum semiovale. The frequency and extent of the foci were closely related to age and to a previous history of cerebrovascular disease. Patients without such a history but with risk factors for cerebrovascular disease tended to have these foci more frequently than those without risk factors.     

Effect of gender on in vivo cartilage magnetic resonance imaging T2 mapping

PURPOSE: To determine if gender is a significant variable for in vivo magnetic resonance imaging (MRI) T2-mapping of knee articular cartilage in young asymptomatic volunteers. MATERIALS AND METHODS: Cartilage MRI T2 mapping was performed in a young healthy population consisting of seven male and 10 female volunteers, 22 to 29 years of age. High-resolution in vivo T2 maps were obtained of patellar, tibial, and weight-bearing femoral articular cartilage. Spatial dependency of cartilage T2 between groups was evaluated through a comparison of cartilage T2 as a function of normalized distance from bone. RESULTS: Bulk cartilage T2 values were similar at all three anatomic sites, and between male and female volunteers. All volunteers demonstrated similar spatial variation in cartilage MRI T2 values, with a minimum located in the radial zone and increasing T2 values toward the articular surface. There was no difference in spatial dependency of cartilage T2 between males and females. CONCLUSION: In young, healthy volunteers, the magnitude and spatial dependency of cartilage T2 does not differ with gender.     

MRI FSE T2和GRE T2*成像技术在脊椎转移瘤中的应用

目的　比较快速自旋回波T2 加权 (FSET2 WI)和梯度回波T2 加权 (GRET2 WI)在脊椎转移瘤中的应用效果。资料与方法　 5 0例脊椎转移瘤患者进行FSET2 WI和GRET2 WI扫描。分别测得正常骨髓、异常骨髓和脊柱背面的信号强度。计算其对比度 /噪声比值 (C/Ns)、信噪比 (SNR)并进行t检验。还对FSET2 WI和GRET2 WI序列对转移灶边界的清晰度进行比较。结果　GRET2 WI所有病灶的C/Ns和SNR均高于FSET2 WI。脊椎转移灶在GRET2 WI上的C/Ns和SNR分别为 2 2 .2 2± 11.5 0和 2 6 .2 1± 15 .96 (平均值±标准差 ) ,在FSET2 图像上分别为4 .19± 5 .0 8和 17.2 3± 11.0 8,两者C/Ns具有显著差异 (t=10 .14 ,P <0 .0 0 1) ;SNR也有明显差异 (t =3.2 7,P <0 .0 1)。并且GRET2 WI对脊椎转移灶边界的显示比FSET2 WI更清晰 (P <0 .0 0 5 )。结论　GRET2 WI比FSET2 WI能更清晰地显示脊椎转移瘤。     

Automated brain extraction from T2-weighted magnetic resonance images

Purpose:

To develop and implement an automated and robust technique to extract brain from T2‐weighted images.

Materials and Methods:

Magnetic resonance imaging (MRI) was performed on 75 adult volunteers to acquire dual fast spin echo (FSE) images with fat‐saturation technique on a 3T Philips scanner. Histogram‐derived thresholds were derived directly from the original images followed by the application of regional labeling, regional connectivity, and mathematical morphological operations to extract brain from axial late‐echo FSE (T2‐weighted) images. The proposed technique was evaluated subjectively by an expert and quantitatively using Bland–Altman plot and Jaccard and Dice similarity measures.

Results:

Excellent agreement between the extracted brain volumes with the proposed technique and manual stripping by an expert was observed based on Bland–Altman plot and also as assessed by high similarity indices (Jaccard: 0.9825 ± 0.0045; Dice: 0.9912 ± 0.0023).

Conclusion:

Brain extraction using the proposed automated methodology is robust and the results are reproducible. J. Magn. Reson. Imaging 2011;33:822–829. © 2011 Wiley‐Liss, Inc.     

Fast T2 mapping of the patellar articular cartilage with gradient and spin-echo magnetic resonance imaging at 1.5 T: validation and initial clinical experience in patients with osteoarthritis

Objective To evaluate the T2 mapping of patellar articular cartilage in patients with osteoarthritis using gradient and spin-echo (GRASE) magnetic resonance (MR) imaging. Materials and methods After the imaging of a phantom consisting of two sealed 50-ml test objects with different concentrations (30% and 90% weight/volume) of copper sulphate, the T2 mapping of patellar articular cartilage was performed in 35 patients (21 male and 14 female; mean age ± SD 42 ± 17 years) with moderate degree of patellar osteoarthritis. Turbo-spin-echo (TSE) (TR milliseconds/minimum–maximum TE milliseconds 3,000/15–120; total acquisition time 5 min 52 s) and GRASE (TR milliseconds/minimum–maximum TE milliseconds 3,000/15–120; total acquisition time 1 min 51 s) were employed. In each patient patellar cartilage was segmented at nine locations (three superior, three central, and three inferior) by manually defined regions of interest. T2 relaxation times were calculated using a linear fit applied to the logarithm of signal intensity decay. Results In the phantom the T2 values measured by GRASE were similar to those measured by MR spectroscopy (test object 1: 48.1 ms vs 51 ms; test object 2: 66.8 ms vs 71 ms; P > 0.05, Wilcoxon test). In patients GRASE and TSE-derived T2 values demonstrated good agreement (mean difference ± SD, 1.81 ± 3.63 ms). The within-patient coefficient of variation was 22% for TSE and 23% for GRASE. Conclusion Fast T2 mapping of the patellar articular cartilage can be performed with GRASE within a third of the time of that of standard sequences. This study was performed thanks to the support of a private grant, “Arduino Ratti”, provided through the Italian Society of Medical Radiology.     

Pictorial review: magnetic resonance imaging of colonic diverticulitis

Magnetic resonance imaging (MRI) is rapidly emerging as a useful imaging modality for the evaluation of the gastrointestinal tract. Increasingly rapid sequences and improving hardware have significantly improved the visualisation of diseases of the colon. MRI has a major advantage over CT in that there is no ionising radiation. In our institution, MRI has increasingly been used as a complimentary imaging modality to CT in the diagnosis and evaluation of diverticulitis and its complications. In this review article, we illustrate the emerging role of MRI in the diagnosis and evaluation of colonic diverticulitis.     

Reactive sclerosis: hyperintense appearance on T2-weighted magnetic resonance imaging

Osteosclerosis is defined as increased density of bone on X-ray imaging studies. It is known that osteosclerosis appears hypointense on both T1- and T2-weighted magnetic resonance imaging sequences. In this review, we present our experience in various sclerotic skeletal pathologies that appear hyperintense on T2-weighted magnetic resonance imaging. We emphasize the possible pathophysiological mechanisms that may cause this appearance, such as bone marrow edema and/or composition of newly formed bone.     

髌骨位置与髌骨软化症之间相关性的MRI研究

目的 运用MRI分析髌骨位置与髌骨软化症之间的关系,并探讨其发生机制及对临床的意义.方法 对1052例患者(男506例、女546例)的膝关节MRI进行分析,其中髌骨软化症患者299例(男100例、女199例).分为1～19、20～39、40～59、≥60岁组,计算阳性率.用Insall-Salvati 法测量所有受检者的髌韧带长度(L)及髌骨纵径长度(P),计算出L/P值.分别用t检验或x2检验对所获数据进行比较,进而研究髌骨位置与髌骨软化症的相关性.结果 髌骨软化症的总阳性率为28.4％( 299/1052),女性为36.4％ (199/546),男性为19.8％ (100/506),女性高于男性(P＜0.01).1 ～19岁组髌骨软化症患者16例(16.8％,l6/95),20～ 39岁组71例(17.9％,71/396);40～59岁组116例(33.2％,116/349);≥60岁组96例(45.3％,96/212),髌骨软化症随年龄增长阳性率增高.正常组与髌骨软化症组L/P值分别为1.15±0.15、1.24 ±0.17,正常男性与女性分别为1.13±0.15,1.17±0.14;男性与女性髌骨软化症患者分别为1.20±0.17、1.26 ±0.16;各年龄组Insall-Salvati指数比较,1 ～19岁病变组与正常组L/P值分别为1.38±0.25、1.24±0.16,20～39岁病变组与正常组分别为1.24±0.17、1.15 ±0.16,40 ～59岁病变组与正常组分别为1.24±0.16、1.12±0.12,≥60岁病变组与正常组分别为1.21±0.16、1.12±0.12,差异均有统计学意义(P值均＜0.01).结论 髌骨软化症的阳性率女性高于男性,随年龄增长阳性率增高,高位髌骨与髌骨软化症的发病有关.     

Age-related structural changes in the young adult brain shown by magnetic resonance diffusion tensor imaging

RATIONALE AND OBJECTIVE: Structure of the brain is generally thought to remain stationary over the course of young adulthood. However, there is some evidence that microstructural changes of the brain do occur during this period. Magnetic resonance diffusion tensor imaging (DTI) provides quantitative measures of structural changes in the brain. We used DTI to detect possible age-related structural changes in the brains of young adults. MATERIALS AND METHODS: Twenty-five healthy adults in their 20s and 30s were studied using DTI. Maps of mean diffusivity and fractional anisotropy (FA) were created for subsequent histogram and region-of-interest analyses, and the results were correlated with the respective ages of the subjects. RESULTS: The histogram analysis revealed a significant increase in the mean FA value (r = 0.407, P < .05) and a significant decrease in FA peak height (r = -0.578, P < .002) with increasing age. No age-related changes were observed in indices derived from mean diffusivity maps. Region-of-interest analysis showed no focal white matter regions with significant FA change. CONCLUSION: Quantitative DTI revealed age-related structural changes in the brains of young adults. Changes on FA histograms observed in this study were considered to be related to changes in the relative volumes of gray and white matter and may represent maturational changes.     

RARE spiral T2-weighted imaging

Spiral imaging has a number of advantages for fast imaging, including an efficient use of gradient hardware. However, inhomogeneity-induced blurring is proportional to the data acquisition duration. In this paper, we combine spiral data acquisition with a RARE echo train. This allows a long data acquisition interval per excitation, while limiting the effects of inhomogeneity. Long spiral k-space trajectories are partitioned into smaller, annular ring trajectories. Each of these annular rings is acquired during echoes of a RARE echo train. The RARE refocusing RF pulses periodically refocus off-resonant spins while building a long data acquisition. We describe both T₂-weighted single excitation and interleaved RARE spiral sequences. A typical sequence acquires a complete data set in three excitations (32 cm FOV, 192 × 192 matrix). At a TR = 2000 ms, we can average two acquisitions in an easy breath-hold interval. A multifrequency reconstruction algorithm minimizes the effects of any off-resonant spins. Though this algorithm needs a field map, we demonstrate how signal averaging can provide the necessary phase data while increasing SNR. The field map creation causes no scan time penalty and essentially no loss in SNR efficiency. Multiple slice, 14-s breath-hold scans acquired on a conventional gradient system demonstrate the performance.     

MRI定量分析髌股关节形态与髌骨软化症之间相关性研究

目的运用MRI测量并分析髌股关节形态参数,探讨其与髌骨软化症(CP)之间相关性。方法回顾性分析经临床及MRI诊断为CP者64例(CP组),测量其髌股关节形态参数,并收集70例无CP者为对照组,比较两组髌股关节形态参数是否存在差异。结果CP发生于髌骨外侧关节面42例;CP组髌Wiberg指数显著小于对照组(P=0.000),髌骨倾斜角、髌骨I-S指数显著大于对照组(P=0.002、0.044);CP组滑车内外侧关节面比值、外侧滑车倾斜角、滑车深度均显著小于对照组(P=0.012、P=0.008、P=0.000),滑车沟角显著大于对照组(P=0.000)。结论CP好发于髌骨外侧关节面;髌骨Wiberg指数、滑车内外侧关节面比值、外侧滑车倾斜角、滑车深度对诊断CP有一定的诊断效能;提示髌骨不稳和滑车发育不良可能是导致CP的病因之一。     

A new approach towards improved visualization of myocardial edema using T2-weighted imaging: a cardiovascular magnetic resonance (CMR) study

Purpose:

To compare T2‐weighted cardiovascular magnetic resonance (CMR) imaging with AASPIR (asymmetric adiabatic spectral inversion recovery) and STIR (short T1 inversion recovery) for myocardial signal intensity, image quality, and fat suppression.

Materials and Methods:

Forty consecutive patients (47 ± 16 years old) referred by cardiologists for CMR‐based myocardial tissue characterization were scanned with both STIR and AASPIR T2‐weighted imaging approaches. Signal intensity of left ventricular myocardium was normalized to a region of interest generating a signal‐to‐noise ratio (SNR). In six patients with regional edema on STIR the contrast‐to‐noise ratio (CNR) was assessed. Two independent observers used a scoring system to evaluate image quality and artifact suppression. Six healthy volunteers (three males, 32 ± 7 years) were recruited to compare fat suppression between AASPIR and STIR.

Results:

SNR of AASPIR was greater than STIR for basal (128 ± 44 vs. 83 ± 40, P < 0.001), mid‐ (144 ± 65 vs. 96 ± 39, P < 0.01), and apical (145 ± 59 vs. 105 ± 35, P < 0.05) myocardium. Improved image quality and greater suppression of artifacts was demonstrated with AASPIR. In patients with regional edema, CNR increased by 49% with AASPIR, while SNR of pericardial fat did not differ (44 ± 39 vs. 33 ± 30, P > 0.05).

Conclusion:

Our findings support the implementation of an AASPIR‐based approach for T2‐weighted imaging due to improved pericardial fat suppression, image quality, and artifact suppression with greater CNR and SNR. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Clinical utility of partial flip angle T2-weighted spin-echo imaging of the brain

Summary To assess the clinical usefulness of partial flip angle (PFA) spin-echo (SE) brain imaging, a total of eighty patients were examined with both conventional double echo T2-weighted SE (2500/30, 80/90^o/one excitation) and PFA double echo SE (1200/30, 70/45^o/two excitations) on 2.0T system. Two comparative studies were performed: (1) in 65 patients PFA SE technique was compared with conventional SE without flow compensating gradients, and (2) in 15 patients the former was compared with the latter with flow compensating gradients. Imaging time was nearly identical in each sequence. In both studies we found that PFA T2-weighted SE images were almost identical to those obtained with the conventional SE technique in the contrast characteristics and the detection rate of the abnormalities (100%, 85/85 lesions), and more importantly, PFA SE revealed few flow artifacts in the brain stem, temporal lobes and basal ganglia which were frequently seen on conventional SE without flow compensating gradients. Additionally, PFA SE images demonstrated no suppression of CSF flow void in the aqueduct which was commonly seen on conventional SE with flow compensating gradients. In overall image quality, the PFA SE images, particularly the second echo images, were almost comparable with those of conventional SE with flow compensating gradients. A flip angle of 45^o seems to be close to Ernst angle, the angle at which maximum signal occurs, for a given TR of 1200 msec for CSF and most of the abnormalities containing higher water content. In conclusion, PFA SE sequence (i. e. 1200/30, 70/45^o/2) appears to be useful as a primary or an adjunctive technique in certain clinical circumstances, particularly in imaging of hydrocephalic patients for assessing aqueductal patency.     

Assessment of relative brain iron concentrations using T2-weighted and T2*-weighted MRI at 3 Tesla

In this paper a new method is presented for the relative assessment of brain iron concentrations based on the evaluation of T₂ and T₂* -weighted images. A multiecho sequence is employed for rapid measurement of T₂ and T₂*, enabling calculation of the line broadening effect ( T₂′). Several groups have failed to show a correlation between T₂ and brain iron content. However, quantification of T₂′, and the associated relaxation rate R₂′, may provide a more specific relative measure of brain iron concentration. This may find application in the study of brain diseases, which cause associated changes in brain iron levels. A new method of field inhomogeneity correction is presented that allows the separation of global and local field inhomogeneities, leading to more accurate T₂* measurements and hence, T₂′ values. The combination of T₂*, and T₂-weighted MRI methods enables the differentiation of Parlkinson's disease patients from normal age-matched controls based on differences in iron content within the substantia nigra.     

Feasibility and reproducibility of relaxometry, morphometric, and geometrical measurements of the hip joint with magnetic resonance imaging at 3T

PURPOSE: To test the feasibility of in vivo magnetic resonance T(1rho) relaxation time measurements of hip cartilage, and quantify the reproducibility of hip cartilage thickness, volume, T(2), T(1rho), and size of femoral head measurements. MATERIALS AND METHODS: The hip joint of five human healthy volunteers, one subject with mild hip osteoarthritis (OA) and one subject with advanced hip OA, was imaged with magnetic resonance imaging (MRI) at 3T. Hip cartilage thickness, volume, T(1rho), and T(2) were quantified, as well as the size of the femoral head. All imaging and analysis procedures were performed twice for the healthy volunteers to assess reproducibility. RESULTS: In vivo MR T(1rho) measurements of hip cartilage at 3T were feasible as demonstrated by high quality images and relaxation time maps. High levels of reproducibility were obtained for measurements of hip cartilage thickness (CV(SD) = 2.19%), volume (CV(SD) = 3.5%), T(2) (CV(SD) = 5.89%), T(1rho) (CV(SD) = 2.03%), and size of femoral head (CV(SD) = 0.49%). Mean T(2) and T(1rho) relaxation time values for human healthy subjects were 28.38 (+/-2.66) msec and 38.72 (+/-3.84) msec, respectively. Mean T(2) and T(1rho) relaxation time values for subjects with OA were 34.78 (+/-8.36) msec and 44.07 (+/-0.99) msec, respectively. T(2) and T(1rho) values increased from the deep to the superficial layers. CONCLUSION: Qualitative and quantitative results indicate that the MRI techniques presented in this study may be applied clinically to patients with OA of the hip to investigate these parameters at different stages of disease.     

Hepatocellular carcinoma with marginal superparamagnetic iron oxide uptake on T2*-weighted magnetic resonance imaging: histopathologic correlation

Purpose

To evaluate the characteristics of hepatocellular carcinomas (HCCs) with marginal superparamagnetic iron oxide (SPIO) uptake on T2*-weighted MRI.

Materials and methods

The study group consisted of 73 patients with 83 surgically resected HCCs. Preoperative SPIO-enhanced MRI studies were retrospectively reviewed. Marginal SPIO uptake was considered positive if a rim-like or band-like low intensity area was present on SPIO-enhanced T2*-weighted images. The prevalence of marginal SPIO uptake was evaluated. Pathological specimens with hematoxylin and eosin staining and immunohistochemical staining of CD68 were reviewed in HCCs with marginal SPIO uptake and 33 HCCs without marginal SPIO uptake (control group).

Results

Ten of 83 (12%) HCCs showed marginal SPIO uptake. All HCCs were hypervascular, and only one nodule showed a nodule-in-nodule appearance on imaging findings. The pathology specimens suggested possible causes of marginal SPIO uptake, including marginal macrophage infiltration in moderately or poorly differentiated HCC (n = 4), residual normal hepatic tissue at the marginal area of confluent multinodular or single nodular with extranodular growth type HCC (n = 3), and a well-differentiated HCC component in nodule-in-nodule type HCC (n = 3). Marginal macrophage infiltration was not seen in the control group.

Conclusion

SPIO-enhanced MRI may be able to demonstrate marginal macrophage infiltration in HCC.