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.     

MRI manifestations of gastrointestinal lymphoma

The magnetic resonance (MR) images of 11 cases of gastrointestinal lymphoma are presented. The findings include irregularly thickened mucosal folds, irregular submucosal infiltration, annular constricting lesion, exophytic tumor growth, mesenteric masses, and mesenteric/retroperitoneal lymphadenopathy. The tumors were homogeneous and intermediate in signal intensity on T1-weighted images. Heterogeneously increased signal intensities were noted on T2-weighted images. There was mild to moderate enhancement after intravenous administration of gadolinium dimeglumine (Gd-DTPA). The submucosal tumor infiltration might be outlined between the strongly GD-DTPA-enhanced mucosa and the low-intensity muscular layer. In one case that received tumor resection, the pathological examination showed destruction of most parts of the muscular layer, and the MR images did not disclose the low intensity muscular zone.     

Dynamic contrast-enhanced MR imaging of fibrolamellar hepatocellular carcinoma

The magnetic resonance (MR) appearance of fibrolamellar hepatocellular carcinoma (FL-HCC) on T1- and T2-weighted and dynamic serial postgadolinium-DTPA images is reported. Both tumors were large (>7 cm in shortest dimension) and had central regions of low signal intensity on T1- and T2-weighted images. Diffuse heterogeneous enhancement of the tumors occurred on immediate postcontrast images. Lesions became more homogeneous in enhancement over time, but lack of enhancement of central portions of the tumor persisted. Although persistent lack of enhancement of the tumor scar on late postcontrast MR images may be characteristic of FL-HCC compared with delayed enhancement in focal nodular hyperplasia, the potential similarities between these tumors is stressed.     

Plain and gadolinium-DTPA-enhanced MR imaging of hepatocellular carcinoma treated with transarterial chemoembolization

Background: To assess unenhanced and gadolinium-enhanced magnetic resonance (MR) imaging patterns of hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE). Methods: Thirty-two patients with 48 HCC lesions underwent MR imaging before and 15 days after TACE. Fifteen lesions were then surgically resected. The remaining 33 lesions were not removed and were followed up with MR imaging at 3, 6, 12, and 18 months after treatment. Spin echo (SE) T1- and T2-weighted and gadolinium-enhanced SE T1-weighted sequences were employed. Qualitative evaluation of signal intensity pattern of the treated lesions was performed in all cases. Histological evaluation and selective hepatic arteriography were considered the gold standard of the study for the 15 resected lesions and the 33 unresected lesions, respectively. Results: On follow-up enhanced T1-weighted images of the 15 resected lesions, seven showed no area of enhancement corresponding to complete necrosis at histologic examination. The remaining eight resected lesions showed areas of enhancement; in six of these cases, viable tumor tissue was found at histology; in the other two lesions, histologic examination revealed the presence of complete tumor necrosis. In the group of resected lesions, T2-weighted images showed no pattern characteristic of necrosis. In 24 of 33 unresected lesions, loss of enhancement on follow-up enhanced T1-weighted images was a characteristic finding, which correlated to devascularization at arteriography. Of these 24 lesions, 17 were completely hypointense on follow-up T2-weighted images; the remaining seven showed small foci of hyperintensity. The other nine unresected lesions showed enhanced portions on follow-up enhanced T1-weighted images, which corresponded to hyperintense areas on T2-weighted images. These findings correlated to persistence of hypervascular areas at arteriography. Conclusion: Gadolinium-enhanced T1-weighted MR imaging is a reliable method for evaluating the outcome of TACE treatment and is more accurate than unenhanced T2-weighted MR imaging. Received: 2 June 1995/Accepted: 18 July 1995     

MR findings of hepatic cavernous hemangioma after intraarterial infusion of iodized oil

Magnetic resonance (MR) imaging was performed on five tumors of three patients who had hepatic hemangiomas. Four tumors were given an intraarterial infusion of 3–8 ml of iodized oil, while one tumor was not. MR images were obtained at 2.0 or 0.5 T. A single spin echo sequence with TE of 30 ms and TR of 500 ms and a double echo sequence with TEs of 60 and 150 ms and TR of 2000 ms, were used to produce relatively T1-, T2-weighted, and heavily T2-weighted images, respectively. Follow-up MR imaging was done 1–5 months after infusion of iodized oil. On relatively T1 weighted images, hemangiomas showed iso or hypointensity. On T2-weighted images, all tumors showed hyperintensity. However, on heavily T2-weighted images, tumors with iodized oil showed heterogeneous, slight hyperintensity, while tumors without iodized oil showed characteristic appearance of marked hyperintensity in hemangiomas. In hepatic cavernous hemangiomas with intraarterial infusion of iodized oil, familiarity with this unusual MR intensity of tumors on heavily T2-weighted images is useful to avoid the incorrect diagnosis and to reduce the frequency of inappropriate hepatic resection.     

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     

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     

MR imaging of mixed hepatocellular and cholangiocellular carcinoma

Two patients with mixed hepatocellular and cholangiocellular carcinoma underwent partial hepatectomy after magnetic resonance (MR) imaging. Correlation is made with the histopathologic manifestations. In both cases the tumors showed relative low signal intensities on T1-weighted spin-echo (SE) images and high signal intensities on T2-weighted SE images. Dynamic MR imaging showed the enhancement from the periphery of the tumor to the inner area gradually and the enhancement continued into the delayed phase. With both cases fibrosis was marked in the inner area of the tumor compared to the peripheral area. The extent and degree of fibrotic tissue is considered to reflect the enhancement on dynamic MR imaging.     

T2-weighted MR imaging for hepatic hemangiomas: comparison of breath-hold and non-breath-hold turbo spin-echo pulse sequences with phased-array multicoil

Background: We compared T2-weighted and heavily T2-weighted breath-hold turbo spin-echo (TSE) sequences with T2-weighted non-breath-hold TSE sequence to evaluate hepatic hemangiomas on magnetic resonance (MR) with a phased-array multicoil. Methods: Twenty-two patients with 27 hemangiomas were studied at 1.0-T scanner by using T2-weighted and heavily T2-weighted breath-hold TSE sequences (18 s each) and non-breath-hold T2-weighted TSE sequences with use of a phased-array multicoil. Images were quantitatively analyzed for tumor-to-liver signal-difference-to-noise ratios (SD/Ns) and tumor-to-liver signal intensity ratios (T/Ls) and qualitatively analyzed for tumor conspicuity and motion-induced image artifacts. Results: Quantitatively, T2-weighted breath-hold TSE images showed the highest SD/Ns among the three sequences, although the differences from the heavily T2-weighted breath-hold TSE sequence and the T2-weighted non-breath-hold TSE sequence were not statistically significant (p= 0.61 and 0.06, respectively). Heavily T2-weighted breath-hold TSE images showed the highest T/Ls among the three sequences. The differences from the T2-weighted breath-hold TSE sequence and the T2-weighted non-breath-hold TSE sequence were statistically significant (p < 0.001). Qualitatively, breath-hold TSE images were superior to non-breath-hold TSE images in terms of tumor conspicuity (p < 0.01) and motion artifacts (p < 0.01). Conclusion: T2-weighted breath-hold TSE sequence is superior to T2-weighted non-breath-hold TSE sequence in the evaluation of hepatic hemangiomas on MR with a phased-array multicoil. Received: 7 April 1997/Accepted: 28 May 1997     

Magnetic resonance imaging and expression of vascular endothelial growth factor in hepatocellular nodules in cirrhosis and hepatocellular carcinomas

We summarized and discussed our previous research results on correlation between magnetic resonance (MR) imaging findings and vascular endothelial growth factor (VEGF) expression in benign or borderline hepatocellular nodules in cirrhosis, hepatocellular carcinomas (HCCs), and in the surrounding liver. Magnetic resonance images were retrospectively correlated quantitatively and qualitatively with VEGF expression in hepatic nodules and in the surrounding liver. By immunohistochemistry, hepatic nodules with moderate to strong immunoreactivity for VEGF showed higher T1 signal intensity, and those with intense immunoreactivity for VEGF showed higher T2 signal intensity. By Western blotting, HCC-to-liver contrast-to-noise ratio correlated with VEGF indices (VEGFs) of hepatocellular carcinomas inversely on opposed-phase T1-weighted, directly on T2-weighted, and marginally and inversely on gadolinium-enhanced hepatic arterial-phase images. On T2-weighted images, standard-deviation ratio of hepatocellular carcinomas correlated directly with VEGFs of hepatocellular carcinomas. Heterogeneities of hepatocellular carcinomas on MR images correlated directly with VEGFs of HCCs on opposed-phase T1-weighted, T2-weighted, hepatic arterial-phase, and equilibrium-phase images. Our results may reflect that MR signal intensity, hepatic arterial vascularity, and heterogeneity of hepatocellular nodules on MR images are closely related to the intensity of VEGF expression as up-regulated by hyper- or hypoxia in the nodules. Gadolinium-enhanced MR imaging may be useful to monitor ischemic state of hepatocelluar nodules. Although real impacts of our results on radiologic practice have been still debatable, we believe that our results may help future radiologic practice in conjunction with biomolecular or genetic treatments for hepatocellular carcinomas.     

Chemotherapy-treated liver metastases mimicking hemangiomas on MR images

BACKGROUND: To report the observation that chemotherapy-treated liver metastases may mimic the appearance of hemangiomas on T2-weighted and serial postgadolinium gradient-echo magnetic resonance (MR) images. METHODS: T2-weighted and serial postgadolinium spoiled gradient-echo images were prospectively and retrospectively analyzed in six patients. All patients had been treated with chemotherapy for a duration of 2-12 months. Histopathologic evaluation of liver lesions was performed in three patients. RESULTS: Twelve lesions that resembled hemangiomas were identified. Lesions were 0.8-5.5 cm in diameter. All were well defined, oval or lobulated, and demonstrated decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images. On immediate postgadolinium images, all lesions demonstrated peripheral nodular enhancement, which coalesced on delayed imaging. Final histopathologic diagnoses were as follows: hepatic metastases from colon cancer (two patients), ovarian cancer (two patients), pancreatic islet cell tumor (one patient), and breast cancer (one patient). CONCLUSIONS: Metastases treated by chemotherapy may mimic the appearance of hemangiomas on a variety of commonly employed MR techniques. In patients undergoing MR imaging for the evaluation of liver metastases, a history of prior chemotherapy administration and duration should be sought to prevent inaccurate staging and inappropriate therapeutic decision making.     

Small intestinal angiolipoma: MR imaging appearance

We report the magnetic resonance imaging finding in a case of small intestinal angiolipoma. Small bowel enteroclysis showed a well-defined, lobulated polypoid lesion in the proximal ileum. The mass showed central high signal intensity with peripheral iso-signal intensity on T1-weighted in-phase images. The central high signal intensity changed to low signal intensity on T1-weighted out-of-phase images. After contrast injection, the mass had a strong enhancement along the periphery of the lesion on fat-saturated T1-weighted images. Characteristic decreased signal intensity on out-of-phase T1-weighted images and strong enhancement on postcontrast images of the small bowel mass suggest the diagnosis of angiolipoma.     

SPIO-enhanced MR imaging of focal fatty liver lesions

BACKGROUND: The purpose of this study was to assess the features of focal fatty liver lesions with superparamagnetic iron oxides (SPIO) on magnetic resonance (MR) images. METHODS: We retrospectively studied five patients with six histologically proven focal fatty liver lesions who had been examined by MR with use of SPIO. The features of the focal fatty liver lesions on two T2-weighted post-SPIO-enhanced MR images, T2*-weighted fast low-angle shot (FLASH) sequences, and T2-weighted turbo-spin echo (TSE) sequences were analyzed, and the percentages of signal intensity loss of the lesions and normal liver parenchyma were calculated. RESULTS: All the fatty liver lesions exhibited different degrees of SPIO uptake, which were presented by a distinct loss of signal intensity on both post-SPIO-enhanced T2-weighted sequences. The percentage of signal intensity loss of the lesions on SPIO-enhanced images was higher than that of normal liver parenchyma in all the cases. CONCLUSION: Focal fatty liver lesions exhibit a high uptake of SPIO. The uptake is higher than that of the normal liver.     

胰岛细胞瘤的影像学表现（附10例分析）

目的胰岛细胞瘤较少见，目前对胰岛细胞瘤的CT表现报道较多，MRI表现报道较少。本研究分析胰岛细胞瘤的CT及MRI表现，着重探讨MRI的诊断价值。方法回顾性分析经手术病理证实的10例胰岛细胞瘤的CT及MRI表现。结果10例胰岛细胞瘤中，8例为功能性胰岛细胞瘤，2例为无功能性胰岛细胞瘤，其中4例为恶性。胰岛素瘤普通CT多表现为等密度，轻度强化，较易漏诊。MRI多表现为T1WI低信号，T2WI高信号，常规增强后轻度强化，动态MRI增强早期可明显强化。功能性胰岛细胞瘤体积多较小，无功能性或恶性胰岛细胞瘤体积多较大。恶性胰岛细胞瘤多伴肝脏或淋巴结转移。结论胰岛细胞瘤的影像学表现具有一定的特征性，MRI较常规CT能提供更多的诊断信息．尤其是动态增强MRI。     

脊柱骨巨细胞瘤的MRI表现

目的探讨脊椎骨巨细胞瘤的MRI表现。方法回顾性分析9例经穿刺或手术病理证实的脊椎骨巨细胞瘤的MRI表现。结果发生于颈椎2例,胸椎3例,腰骶椎4例,共累及13个椎体,除2例椎体呈破坏塌陷改变外,其余椎体呈不同程度的膨胀性破坏,T1WI呈等、低信号,T2WI常呈混杂信号,呈低、中等或高信号,增强扫描呈不同程度均匀强化。结论MRI对脊柱骨巨细胞瘤有很高的诊断价值。     

原发性骨骼淋巴瘤的影像学诊断

目的:分析13例骨骼淋巴瘤的影像学特征以探讨其影像学的诊断价值。材料和方法:13例经手术病理证实的骨骼淋巴瘤病例,术前均经平片检查,其中CT检查10例,MR检查9例。结果:4例何杰金淋巴瘤和9例非何杰金淋巴瘤分别累及脊柱6例,长管状骨5例,骨盆2例,病变主要累及脊柱的椎体和长管状骨的骨干,骨质改变为溶骨型9例(69%)和混合型4例(31%),骨质破坏以浸润性虫噬状骨质破坏为主;骨皮质破坏11例,但皮质破坏的程度总是很轻微;骨膜成骨3例(23%),软组织肿块形成7例(54%)。软组织肿块CT表现为低密度或等密度,境界清楚;骨骼MRI T1WI低信号9例,T2WI显示为略低信号2例,等信号2例,高信号5例;软组织肿块的MR信号变化少,T1WI略低于肌肉,T2WI总是略高于肌肉,MR动态增强扫描为轻~中等程度强化。结论:骨骼淋巴瘤影像学特征:①明显的浸润性虫噬状骨质破坏,而骨皮质破坏轻微,骨膜反应少见;②软组织肿块T2WI信号略高,且信号相对均匀。平片、CT和MRI等影像学检查可以作出诊断。     

Mosaic pattern of encapsulated hepatocellular carcinoma: Correlation of magnetic resonance imaging and pathology

Internal architecture of an encapsulated hepatocellular carcinoma (HCC) was studied with magnetic resonance imaging and histologic correlation. The capsule of HCC showed low intensity relative to liver on both T1- and T2-weighted images. The T1-weighted images were superior to the T2-weighted images in delineating the capsule of HCC. The tumor showed a mosaic pattern, which was a configuration composed of multiple compartments of different intensities, reflecting viable tumor nodules and a necrotic portion. Viable tumor nodules, composed of trabeculae of polygonal cells resembling the normal liver cell with well-formed sinusoids, showed low intensity relative to liver on T1-weighted images and high intensity on T2-weighted images. The necrotic portion, composed of coagulation of amorphous, thick eosinophilic material without hemorrhage or inflammatory reaction, showed low intensity relative to liver on both T1- and T2-weighted images. The T2-weighted images were superior to the T1-weighted images in demonstrating the mosaic pattern of HCC.     

乳腺恶性纤维组织细胞瘤的MRI诊断(附3例报告)

目的探讨MRI对乳腺恶性纤维组织细胞瘤(MFH)的诊断价值。材料与方法回顾性分析经手术病理证实的3例乳腺恶性纤维组织细胞瘤的临床资料及MRI影像学特征。结果 3例MFH肿块均较大,均有囊变、坏死,肿瘤在T1WI上均呈低信号,在T2WI上均呈不均匀高、低、等混杂信号;3例于T2WI上肿瘤内显示低信号分隔样结构。结论 MRI对乳腺恶性纤维组织细胞瘤的诊断具有重要价值,但是确诊需要手术及病理检查。     

MR imaging of hepatocellular carcinoma at 1.5 Tesla

The authors investigated the magnetic resonance appearance of hepatocellular carcinoma using a 1.5-Tesla magnet. Twenty-four patients with pathologically proven hepatocellular carcinoma had magnetic resonance imaging (MRI) studies, which were retrospectively reviewed. All patients were imaged with at least two of the following techniques: (1) T1-weighted (T1W), (2) T1-weighted with Gd-DTPA enhancement (T1W-E), (3) T2-weighted (T2W), (4) proton density (PD), and (5) gradient-recalled echoes (GRE). T1W images were equal to T2W images for tumor detection using a grading system. T1W images were slightly better than T2W images for the total number of lesions detected. The other pulsing techniques (PD, T1W-E, and GRE) detected fewer lesions. Eight cases of hepatocellular carcinoma (33%) had nonhomogeneous increased signal intensity on both T1W and T2W images. The authors conclude that T1W images are equal to T2W images for detection of hepatocellular carcinoma. The authors also conclude that 33% of hepatocellular carcinomas have an imaging pattern with increased signal intensity on both T1W and T2W images. This pattern is atypical for most other hepatic masses and hence can be used to suggest the mass is hepatocellular carcinoma.     

磁共振T_1加权像在急性闭塞性脑血管病诊断中的价值

目的　评价磁共振T1加权像在急性闭塞性脑血管病诊断中的价值。方法　急性闭塞性脑血管病 15例 ,其中急性脑皮层动脉闭塞 9例 ,急性脑静脉窦闭塞 6例。结果　 9例急性脑皮层动脉闭塞 ,T1加权像上MR信号强度正常 ,但可见梗死区脑肿胀征象 ;T2 加权像时 ,病变区信号强度无异常发现。 6例急性脑静脉窦闭塞中 ,横窦和乙状窦闭塞 4例 ,上矢状窦后 1/ 3处闭塞 2例。T1加权像见闭塞的静脉窦血管流空影消失 ,静脉窦呈稍高信号强度影。此外 ,相应静脉回流区可见脑肿胀征象。T2 加权像也可见闭塞的静脉窦血管流空影消失 ,但脑组织内无异常信号改变。结论　急性闭塞性脑血管病 (皮层动脉或大静脉窦闭塞 )的MR检查中 ,T1加权像形态学变化要早于T2加权像信号的变化。