MR imaging features of uterine adenomyomas

Background

To evaluate the magnetic resonance (MR) imaging features of uterine adenomyoma in comparison with histopathologic findings.

Materials and methods

MR images of seven patients who had surgically proven uterine adenomyoma were retrospectively reviewed by two radiologists in consensus regarding the morphologic appearance, including tumor size, location, margin, presence of concomitant adenomyosis, presence and signal intensity of cavity within tumor, and signal intensity and enhancement pattern of solid portion of tumor. MR imaging findings were correlated with histopathologic findings.

Results

Tumor location was submucosal in three cases, subserosal in two, and mixed mural/subserosal in two. All tumors were well circumscribed on T2-weighted images and contrast-enhanced fat-suppressed T1-weighted images. In six cases, well defined cavities of high signal intensity, which reflected hemorrhagic cavities pathologically, were demonstrated within the tumors on T1-weighted images. Concomitant adenomyosis was observed in five cases. Solid portion of all tumors except hemorrhagic cavities exhibited iso-signal intensity on T1-weighted images, various signal intensity on T2-weighted images, and homogeneous enhancement on contrast-enhanced fat-suppressed T1-weighted images in five cases.

Conclusion

When MR imaging shows a well circumscribed mass with hemorrhagic cavities of high signal intensity on T1-weighted images and concomitant adenomyosis in the uterus, adenomyoma should be considered in the differential diagnosis.     

Struma ovarii: appearance on MR images

Background: The purpose of this multi-institutional study was to examine the appearance of struma ovarii on magnetic resonance (MR) images. Methods: MR images of 12 patients with histologically proven struma ovarii were retrospectively reviewed. All patients underwent T1-weighted and T2-weighted imaging. Contrast-enhanced T1-weighted images with Gd-DTPA were available in 10 patients. The following determinations were made: tumor morphology, signal intensities, contrast-enhancement effects of solid components with Gd-DTPA, and comparison of MR images with resected specimens. Results: All 12 patients had both cystic and solid components, with a multilobulated surface and thickened septa. Signal intensities on T1-weighted images were mainly low, partly intermediate to high, or high, and those on T2-weighted images were mainly high, with different signal intensities. Contrast-enhancement effects were marked or moderate. The contents that showed low signal intensities on T1-weighted images and signal voids or low signal intensities on T2-weighted images were viscid gelatinous materials. Conclusions: A multicystic tumor with a solid component, a multilobulated surface, and signal intensities that indicate the presence of viscid gelatinous materials appear to be a characteristic MR finding of struma ovarii. Received: 10 April 1997/Accepted after revision: 7 July 1997     

Ovarian mucinous cystadenoma coexisting with benign Brenner tumor: MR imaging findings

Purpose

The purpose of this study was to describe the MR imaging findings of ovarian mucinous cystadenomas coexisting with benign Brenner tumors.

Materials and methods

MR images with a 1.5-T unit obtained in five consecutive patients (age range, 51–72 years; mean age, 61 years) with surgically confirmed ovarian mucinous cystadenomas coexisting with benign Brenner tumors were retrospectively reviewed for the presence, configuration, and signal intensity of cystic and solid components of the lesions.

Results

Tumors ranged in size from 7.5 to 22.1 cm (mean, 13.5 cm). In four patients (80%), the size of mucinous cystadenoma (range 6.4–22.1 cm; mean, 12.5 cm) was larger than that of Brenner tumor (range 0.2–9.1 cm; mean, 2.8 cm). All patients (100%) had cystic, and three (60%) had solid components. Four patients (80%) showed multilocular cystic, and one (20%) showed unilocular cystic appearance. MR imaging findings were classified into three patterns: (1) a bulky solid mass adjacent to the cystic component, (2) a mural nodule at the periphery of the cystic component, and (3) a cystic component without a detectable solid component. All four multilocular cystic areas exhibited “stained glass” appearances on both T1- and T2-weighted images, and all three solid areas showed homogeneous hypointensity on T2-weighted images.

Conclusion

Mucinous cystadenomas were often larger than the coexisting benign Brenner tumors. Mucinous cystadenomas coexisting with benign Brenner tumors should be considered when multilocular or unilocular cystic components are accompanied by homogeneously hypointense solid components on T2-weighted images.     

卵巢甲状腺肿MRI和CT表现

目的 分析卵巢甲状腺肿的MRI、CT表现。方法 回顾性分析14例经手术病理证实的单发卵巢甲状腺肿患者的MRI及CT表现,观察其形态、大小、密度/信号、强化特点等。结果 14例病变均表现为包膜完整的囊实性肿块,其中分叶状11例,类圆形3例;多囊状13例,单囊1例;11例实性成分为明显厚壁或分隔,3例呈结节状。肿瘤最大径为3~34 cm,平均（11.34±2.24） cm。7例MR T2WI囊性部分均可见极低信号区,增强后无强化,实性成分明显强化。7例CT囊性部分均可见高密度区,CT值57~90 HU,增强扫描未见强化;实性成分明显强化,CT值为145~270 HU;4例囊壁或实性结节中见斑片状钙化。结论 卵巢甲状腺肿的MRI、CT表现具有一定特征性,有助于诊断及鉴别诊断。     

Hepatic pseudolymphoma: imaging–pathologic correlation with special reference to hemodynamic analysis

Objectives

To clarify radiological findings and hemodynamic characteristics of hepatic pseudolymphoma, as compared with the histopathological findings.

Methods

Radiological findings of ten histopathologically confirmed hepatic pseudolymphomas in seven patients were examined using US, CT, and MRI. Six patients also underwent angiography-assisted CT, including CT during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) to analyze hemodynamics.

Results

The nodules were depicted as hypoechoic on US, hypodense on precontrast CT, hypointense on T1-weighted images, and hyperintense on T2-weighted images. On contrast-enhanced CT/MRI, they showed various degrees of enhancement, and sometimes, perinodular enhancement was observed at the arterial dominant and/or equilibrium phase. On CTAP, the nodules showed portal perfusion defects, including some in the perinodular liver parenchyma. On CTHA, irregular bordered enhancement was observed in perinodular liver parenchyma on early phase, and continued until delayed phase. Some nodules had preserved intra-tumoral portal tracts. Histopathologically, the nodules consisted of marked lymphoid cells. In perinodular liver parenchyma, stenosis or disappearance of portal venules, caused by lymphoid cell infiltration in the portal tracts, was observed.

Conclusions

Hepatic pseudolymphoma showed some characteristic radiological findings including hemodynamics on CT, MRI, and angiography-assisted CT. These findings are useful in the differentiation from hepatocellular carcinoma and other tumors.     

Automated aorta segmentation in low-dose chest CT images

Purpose

   Abnormalities of aortic surface and aortic diameter can be related to cardiovascular disease and aortic aneurysm. Computer-based aortic segmentation and measurement may aid physicians in related disease diagnosis. This paper presents a fully automated algorithm for aorta segmentation in low-dose non-contrast CT images.

Methods

   The original non-contrast CT scan images as well as their pre-computed anatomy label maps are used to locate the aorta and identify its surface. First a seed point is located inside the aortic lumen. Then, a cylindrical model is progressively fitted to the 3D image space to track the aorta centerline. Finally, the aortic surface is located based on image intensity information. This algorithm has been trained and tested on 359 low-dose non-contrast CT images from VIA-ELCAP and LIDC public image databases. Twenty images were used for training to obtain the optimal set of parameters, while the remaining images were used for testing. The segmentation result has been evaluated both qualitatively and quantitatively. Sixty representative testing images were used to establish a partial ground truth by manual marking on several axial image slices.

Results

   Compared to ground truth marking, the segmentation result had a mean Dice Similarity Coefficient of 0.933 (maximum 0.963 and minimum 0.907). The average boundary distance between manual segmentation and automatic segmentation was 1.39 mm with a maximum of 1.79 mm and a minimum of 0.83 mm.

Conclusion

   Both qualitative and quantitative evaluations have shown that the presented algorithm is able to accurately segment the aorta in low-dose non-contrast CT images.     

Detection of body packing by magnetic resonance imaging: a new diagnostic tool?

Purpose

In this study, we aimed to describe non-contrast abdominal MRI findings in body packers and emphasize the role of this imaging technique in diagnosis of body packing.

Materials and methods

Non-contrast abdominopelvic MRI was performed at the radiology department in 16 suspected body packers that were brought to our hospital, and 13 of them were diagnosed with body packing. We evaluated the presence, location, and shapes of packets as well as signal characteristics on T1- and T2-weighted images.

Results

We came across two types of packets: those containing solid substances (10 cases) and those filled with liquid cocaine (3 cases). Both types were accurately diagnosed with the help of MRI. Only 1 suspected body packer received a false positive diagnosis.

Conclusion

Abdominopelvic MRI is a reliable and valuable method of diagnosing body packing.     

Retroperitoneal schwannomas in the anterior pararenal space: dynamic enhanced multi-slice CT and MR findings

Background

To evaluate the imaging features of schwannomas in the anterior pararenal space (APS), especially focusing on dynamic enhanced multi-slice CT (MSCT) and MR findings.

Patients and methods

Eight patients with pathologically proved retroperitoneal schwannomas in the APS underwent dynamic enhanced multi-slice CT (MSCT), while three of these patients also had a contrast-enhanced MR examination. The imaging findings were retrospectively reviewed.

Results

All eight cases exhibited forward displacement of the pancreas, and three cases showed lateral displacement and compression of the inferior vena cava. The tumors had round or oval shape with a maximal axial diameter of 4.0–12.3 cm (average, 6.7 cm). All eight tumors were solitary and well circumscribed. Of the eight retroperitoneal schwannomas in the APS, six exhibited a capsule with thickness of 1.0–2.0 mm, one showed punctate calcification, two displayed cystic degeneration, and three revealed a “target sign” on CT and MR. The tumors were hypo-dense on unenhanced CT images, hyper-intense on T2W images, and homogeneously hypo-intense on T1W images. All eight tumors exhibited gradual enhancement on dynamic enhanced CT or MR images. One case showed delayed enhancement. Heterogeneous enhancement was the dominant pattern occurring in seven out of eight tumors.

Conclusion

The imaging findings of schwannoma in the APS correspond with its pathological composition. Schwannoma should be included in the differential diagnosis of tumors in the APS.     

Struma ovarii: MR appearances

Background: Analysis of unenhanced and contrast-enhanced magnetic resonance (MR) images of struma ovarii, a rare benign neoplasm of the ovary, is the aim of this study. Methods: T2-weighted and Gd-DTPA-enhanced T1-weighted MR images of five histologically proven struma ovarii were evaluated retrospectively. Results: In all patients, unenhanced and contrast-enhanced T1-weighted MR images showed complex cystic masses composed of multiple cysts and a solid component, indicating the presence of large and small thyroid follicles. In four patients, the cyst fluid was hypointense on T1-weighted images and hyperintense on T2-weighted images. In one patient, the fluid was hyperintense on T1-weighted images and hypointense on T2-weighted images due to hemorrhage. Conclusion: A complex mass composed of multiple cysts and a solid component, indicating the presence of large and small thyroid follicles, appeared to be a characteristic MR finding of struma ovarii. Received: 11 December 1995/Accepted: 15 December 1995     

副神经节瘤的CT和MRI表现

目的：探讨CT和MRI在副神经节瘤中的诊断价值.方法：回顾性分析26例经手术或病理证实的副神经节瘤的CT和MRI表现,所有26例均行CT扫描,16例行MRI检查.分析肿瘤的位置、大小、形态、密度、信号特点及强化方式.结果：CT表现为边界清楚或不清楚的软组织肿块,肿块呈圆形或类圆形和不规则形.平扫呈等低密度者23例,高密度者3例,增强多为持续性强化,动脉期中度-明显强化,实质期明显强化,延迟期强化程度轻度减低,24例增强后强化不均,病灶内见斑片状出血坏死区,2例强化均匀,1例病灶内有钙化,2例可见病灶周围水肿表现,1例侵犯邻近骨质.6例恶性者肿块向周围结构侵犯,伴有肝脏、双肺或淋巴结转移.肿瘤最大径线为2.5～13.5 cm（平均6.38 cm）.MRI上副神经节瘤多表现为较大软组织肿块,T1WI呈等低信号,T2WI为中等或高信号或不均匀混杂信号,DWI呈高信号,增强扫描肿瘤实质部分明显强化.结论：CT和MRI是副神经节瘤定位、定性诊断的重要影像学检查方法,CT能够很好地显示肿瘤本身及其与周围结构的关系,MRI的信号变化能够反映肿瘤组织学成分的不同,CT和MRI在早期发现病灶、副神经节瘤的诊断与鉴别、判断病灶与周围组织结构的关系方面具有重要意义.     

Well-differentiated hepatocellular carcinoma: findings of US, CT, and MR imaging

Background: To elucidate the imaging characteristics of well-differentiated hepatocellular carcinomas (HCCs) on ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. Methods: Ultrasonograms, CTs, and MR images of 18 histopathologically proven well-differentiated HCCs in 15 patients were reviewed. The findings of these images were correlated with histopathologic findings. Results: On US, seven tumors were depicted as a hyperechoic area and eight as a hypoechoic area. Three tumors were not visualized. On precontrast CT, four tumors were depicted as a low-density area, but 14 were not visualized. On conventional contrast-enhanced CT, 12 tumors were depicted as a low-density area but six were not visualized. On T1-weighted MR images, 10 tumors had high signal intensity and two had low signal intensity. Six tumors were not visualized. On T2-weighted MR images, five tumors had high signal intensity and two had low signal intensity. Eleven tumors were not visualized. Tumors with fatty change and/or clear cell formation were frequently hyperechoic on US and hyperintense on T1-weighted MR images. Conclusions: Well-differentiated HCCs show different findings on US, CT, and MR imaging. Therefore, reliable diagnosis of well-differentiated HCCs by these imaging techniques may be difficult. Received: 29 April 1998/Revision accepted: 15 July 1998     

超声联合增强CT诊断卵巢甲状腺肿

目的 探讨超声联合增强CT诊断卵巢甲状腺肿（SO）的价值。方法 回顾性分析17例经手术病理证实的SO患者的声像图及增强CT特点,并与病理结果对照。结果 17例包括良性14例及恶性3例SO,其中10例囊实混合性,6例多囊性,1例单纯实性。超声于6例肿瘤实性部分发现 "甲状腺肿突起",CT值35~82 HU[平均(61.5±12.1)HU];囊性部分呈无回声或低回声,对应CT值13~89 HU[平均(43.4±22.7)HU];其中7例含"高密度囊"（CT值>50 HU）。CT增强显示14例实性成分及囊壁强化,其中9例明显强化或呈特征性"甲状腺样强化",对应的CDFI未见明显血流。结论 SO多为囊性或囊实性肿块;实性成分显著强化结合CDFI少量血流信号不一致、囊液CT值增高结合声像图无回声或低回声不一致可能是SO的特异性影像学表现。     

血管外皮细胞瘤与孤立性纤维瘤的诊断和鉴别诊断

目的血管外皮细胞瘤和孤立性纤维瘤同属纤维母细胞/肌纤维母细胞来源肿瘤的中间性肿瘤,病理和组织学方面重叠表现多,术前误诊率高。本文分析各自影像学特征,探讨其影像学诊断和鉴别诊断的价值。方法回顾性分析经手术病理证实的9例血管外皮细胞瘤和8例孤立性纤维瘤病例,术前经螺旋CT或MR检查,仔细复习CT和MRI扫描结果并和手术病理作回顾性对照分析。结果9例血管外皮细胞瘤病灶中,位于颅内3例,四肢4例,腹膜后1例,腹股沟1例;肿瘤直径4.8-13.5 cm,平均6.7 cm;瘤内见蚯蚓和结节状异常信号6例,不同程度坏死9例;所有肿瘤实质成分T1WI为等或略低信号,T2WI为略高信号;其中,6例行动态增强,动脉期显著强化5例,中等程度强化1例,所有病例门脉期强化程度与血管相仿。8例孤立性纤维瘤中,位于胸部4例,四肢2例,腹腔1例,盆腔1例;肿瘤直径4.0-22.5 cm,平均9.3 cm;密度或信号较均匀5例,不同程度坏死3例,伴点状钙化1例。CT平扫密度与肌肉密度相仿,内可见两种不同密度的实质成分;CT动脉期呈地图样或线样葡行强化,门脉期持续强化,强化趋于均匀;MRSE T1WI呈等信号,T2WI为略高信号,T2 WI脂肪抑制为高信号;MR动脉期明显强化,门脉期持续强化。结论血管外皮细胞瘤和孤立性纤维瘤具有较明显的影像学特征,影像学可以诊断和鉴别多数病例。     

Rectal cancer in inflammatory bowel diseases: MR imaging findings

Purpose

To retrospectively analyze the MR imaging features of rectal cancer in patients with inflammatory bowel diseases (IBD).

Materials and methods

The MR imaging examinations of 13 patients with IBD-related rectal cancer were retrospectively reviewed. MR imaging included T2-weighted, diffusion-weighted (DW), and gadolinium chelate-enhanced MR imaging. MR imaging findings were analyzed and compared with endoscopic and histopathological findings.

Results

Eight patients (8/13; 62%) had active IBD and five (5/13; 38%) had quiescent IBD on MR imaging. Two different tumor patterns were individualized including clearly visible soft-tissue mass (4/13; 31%) (Type 1 tumor) and marked circumferential rectal wall thickening (9/13; 69%) (Type 2 tumor). Twelve tumors (12/13; 92%) showed high signal intensity on T2-weighted MR images. All six tumors studied with DW-MR imaging (6/6; 100%) showed high signal on DW-MR imaging with restricted diffusion on apparent diffusion coefficient (ADC) map. On gadolinium chelate-enhanced MR imaging, heterogeneous enhancement was observed in one tumor (1/13; 8%), whereas 12 tumors (12/13; 92%) showed homogeneous enhancement. MR imaging showed pelvic fistula and intrapelvic abscess in association with four (4/13; 31%) and two tumors (2/13; 15%), respectively.

Conclusion

Our limited retrospective study demonstrates that rectal cancer in IBD patients can present as a circumferential wall thickening resembling inflammation and can occur in the absence of fistula or abscess. The use of T2-weighted and DW-MR imaging is recommended to improve rectal cancer detection in patients with long-standing IBD.     

Struma ovarii: CT findings

Background  The purpose of this study was to evaluate computed tomographic findings of struma ovarii. Methods  Computed tomography (CT) scans of 13 pathologically proven struma ovarii were retrospectively reviewed by two radiologists in consensus. Scans were evaluated for the laterality, size, mass configuration, margins, internal architecture, presence of intracystic high attenuation lesions on precontrast scans, and cyst wall enhancement. Results  The mean size of the tumors was 11.4 cm (range 4.7–21.0 cm). Mainly cystic (n = 8, 61.5%) or cystic (n = 5, 38.5%) appearance was common to all the tumors. All tumors were unilateral and had smooth margins. The most common internal architecture in the tumors was multicystic architecture (n = 11, 84.6%). Eleven tumors (84.6%) showed a high attenuation lesion in the cyst portion of the mass on precontrast scans and the attenuation ranged from 92.2 to 120.5 Hounsfield units (HU) (mean, 106.8 ± 8.8 HU). The cyst wall showed no (n = 7, 53.8%), moderate (n = 5, 38.5%), or marked (n = 1, 7.7%) enhancement after administration of contrast medium. Conclusions  On CT scans, struma ovarii appeared most often as a smooth marginated multicystic mass with a high attenuation lesion on precontrast scans and no or moderate cyst wall enhancement.     

Primary hepatic neuroendocrine carcinoma: MR imaging findings including preliminary observation on diffusion-weighted imaging

Purpose

To investigate MR imaging findings of primary hepatic neuroendocrine carcinoma (PHNEC) including preliminary observations on diffusion-weighted imaging (DWI).

Materials and methods

MR images of eight patients with pathologically confirmed PHNEC were retrospectively analyzed. The morphological characteristics and dynamic enhancement patterns were evaluated.

Results

One case showed a well-defined solitary nodule with homogenous hypointensity on T1-weighted imaging (T1WI) and hyperintensity on T2-weighted imaging (T2WI) and DWI. The remaining seven cases appeared as well-defined dominant masses with multiple satellite nodules. The dominant masses demonstrated heterogeneous hypointensity on T1WI and hyperintensity on T2WI, which all appeared as a marked enhancement at arterial phase and rapid washout at portal venous phase. Six cases demonstrated rim-like enhancement at equilibrium phase. The satellite lesions showed heterogeneous hypointensity on T1WI and marked hyperintensity on T2WI with variable enhancements, such as homogeneous, rim-like enhancement. All the dominant masses and satellite nodules appeared as markedly hyperintensity and reduced apparent coefficient (ADCs) values on DWI. The mean ADC value of the tumors was significantly lower than that of surrounding liver parenchyma (1.02 ± 0.57 vs. 2.24 × 10^?3 mm²/s, p = 0.000).

Conclusion

PHNECs typically appear as a large dominant hypervascular mass accompanied by satellite nodules, with rapid washout and capsular enhancement on dynamic MR imaging and restricted diffusion on DWI.     

Multi-modality imaging findings of splenic hamartoma: a report of nine cases and review of the literature

Purpose

To investigate the presentation of splenic hamartomas (SHs) on ultrasonography (US), CT and MRI.

Methods

Nine patients (5 males and 4 females, mean age, 52.8 years) with pathologically proven SHs were included in this study. US, CT and MRI images were analyzed retrospectively, and imaging features were correlated with pathological findings.

Results

SHs appeared solitary lesion (n = 8) and multiple lesions (n = 1) in the present study. (1) In 8 cases of solitary lesion, the lesions appeared as solid nodules or masses with well-defined margins and varying echogenicity (hyperecho = 5, hypoecho = 2, strong echo = 1) on ultrasound. The lesions showed iso-attenuation (n = 3) or slightly hypo-attenuation (n = 4) on unenhanced CT, and calcification were revealed in 3 lesions. MRI showed isointensity (n = 3) or hypointensity (n = 2) on the T1-weighted image, and heterogeneous hypointensity (n = 2), slightly hyperintensity (n = 2) and hyperintensity (n = 1) on the T2-weighted image. The enhanced patterns of SHs showed mild diffuse heterogeneous enhancement (n = 6) and prominent enhancement (n = 1) during arterial phase and above 7 lesions were demonstrated progressive enhancement at delayed phase on enhanced CT. One lesion without any enhancement was revealed in another patient. (2) One case of multiple lesions included 1 cystic lesion with irregular calcification and 7 solid lesions with progressive enhancement on CT images.

Conclusions

Combination of a variety of imaging modalities could more fully reflect the pathological characteristics and contribute to the diagnosis of SH.     

Non-invasive Monitoring of Pancreatic Tumor Progression in the RIP1-Tag2 Mouse by Magnetic Resonance Imaging

Purpose

Assessing information on tumor progression in the RIP1-Tag2 mouse in vivo is a great challenge because the tumors form spontaneously throughout the pancreas and are difficult to detect with current imaging modalities. In this study, we focused on non-invasive magnetic resonance imaging, providing information on tumor growth.

Procedures

Tissue relaxation times were measured over time and were compared between tumors and healthy pancreatic tissue. The effects of age and body temperature on these relaxation times, possibly influencing image contrast and therefore detection capabilities, were evaluated.

Results

Tumors appeared hyperintense in T2-weighted images when they exceeded 0.8 mm in diameter, and both relaxation times showed significantly higher values in tumors than in the healthy pancreas.

Conclusion

Visualization and monitoring of these small tumors in vivo is feasible, even under adverse conditions of permanent gut movement. In the mouse model studied, the relaxation times of tumors differed significantly from healthy pancreatic tissue.     

Ultra-short echo time cardiovascular magnetic resonance of atherosclerotic carotid plaque

Background

Multi-contrast weighted cardiovascular magnetic resonance (CMR) allows detailed plaque characterisation and assessment of plaque vulnerability. The aim of this preliminary study was to show the potential of Ultra-short Echo Time (UTE) subtraction MR in detecting calcification.

Methods

14 ex-vivo human carotid arteries were scanned using CMR and CT, prior to histological slide preparation. Two images were acquired using a double-echo 3D UTE pulse, one with a long TE and the second with an ultra-short TE, with the same TR. An UTE subtraction (ΔUTE) image containing only ultra-short T2 (and T2*) signals was obtained by post-processing subtraction of the 2 UTE images. The ΔUTE image was compared to the conventional 3D T1-weighted sequence and CT scan of the carotid arteries.

Results

In atheromatous carotid arteries, there was a 71% agreement between the high signal intensity areas on ΔUTE images and CT scan. The same areas were represented as low signal intensity on T1W and areas of void on histology, indicating focal calcification. However, in 15% of all the scans there were some incongruent regions of high intensity on ΔUTE that did not correspond with a high intensity signal on CT, and histology confirmed the absence of calcification.

Conclusions

We have demonstrated that the UTE sequence has potential to identify calcified plaque. Further work is needed to fully understand the UTE findings.     

Feasibility of blood oxygenation level-dependent MRI at 3T in the characterization of hepatic tumors

Purpose

To determine the feasibility of using blood oxygenation level-dependent (BOLD) MRI in the characterization of hepatic tumors.

Methods

A total of 100 patients with 43 hepatocellular carcinomas (HCCs), 36 metastases, 17 cholangiocarcinomas, and 23 hemangiomas underwent gadoxetic acid-enhanced and BOLD MRI at 3T. BOLD MRI was performed using a multiple fast-field echo sequence (TR/TE, 290/10–28; slice thickness 5 mm) to generate 20 T2*-weighted images. The T2* value of each tumor were calculated. On a color-coded T2* map, tumors were classified into five categories of high signal intensity (strong, moderate, rim, mild) and iso-intensity, which was correlated with the enhancement pattern on dynamic phases by two observers.

Results

The mean T2* value (ms) of hemangiomas (97.3 ± 20.2) was the highest, followed by HCCs (48.4 ± 12.7), metastases (37.1 ± 10.5), and cholangiocarcinomas (36.6 ± 11.1). These values were significantly different (hemangioma vs. others tumors and HCC vs. metastasis or cholangiocarcinoma) (P ≤ 0.001). The agreement between the T2* color map and dynamic images was moderate for all tumors (k = 0.544), good for tumors >2.0 cm (k = 0.666), and fair for tumors ≤2.0 cm (k = 0.334). With the gadoxetic acid-enhanced MRI used as a reference, the sensitivities of BOLD MRI (T2* color map) for displaying hypervascularity of HCC (categories of 1–3) were 81.0 % (n = 34/42) and 78.6 % (n = 33/42) for both observers.

Conclusion

Liver BOLD MRI has a potential to predict the vascular pattern of hepatic tumors.