肝脏局灶性结节增生的平扫及动态增强MRI表现

目的分析肝脏局灶性结节增生(FNH)MRI平扫及动态增强表现,提高对该病的认识和诊断水平。方法回顾性分析19例共20个经手术病理证实的FNH病灶,所有病例均行MRI平扫及动态增强检查,对病灶的MRI特征进行评价。结果18例为单发病灶,1例为2个病灶,病灶位于左外叶6个、左内叶9个、右后叶4个、尾状叶1个;病灶大小平均为3.6cm×4.5cm;与肝实质比较,平扫T1WI序列为稍低信号、T2WI序列为稍高信号者16个,T1WI及T2WI为等信号者4个,9个病灶内见瘢痕,呈长T1长T2信号。动态增强扫描动脉期18个病灶明显强化,1个病灶中等程度强化,1个病灶周边轻度强化,2个病灶周边出现扭曲血管;门脉期信号高于周围肝实质者17个,等信号2个,信号相对低于肝实质1个;延迟期仍为高信号者14个,另5个表现为等信号,1个为稍低信号;门脉期和延迟期有3个病灶周围可见细环状包膜;15个病灶增强后其内可见瘢痕影,瘢痕于动脉期、门脉期均为低信号,延迟强化者4例。所有病灶周围静脉显示良好。结论MRI平扫及动态增强扫描能较好地显示FNH的内部结构和信号特点,反映病灶的血供特点和病理特征,有助于和肝脏其他病变相鉴别。     

肝脏局灶性结节增生的MRI表现与病理对照分析

目的：分析肝脏局灶性结节增生（FNH）的平扫和动态增强的MRI表现及诊断价值，提高FNH诊断的准确率。方法：回顾性分析15例（16个病灶）经病理证实的FNH的平扫及动态增强MRI表现。结果：16个病灶于T1WI呈略低信号或等信号，T2WI呈略高信号或等信号。增强扫描动脉期呈明显强化，在门脉期及延迟期呈等或略高强化。5个病灶在平扫MRI上显示中央瘢痕，11个病灶在动态增强MRI上显示中央瘢痕，均见延迟强化。结论：平扫和动态增强MRI检查能较全面显示FNH的病理特征和血供特点，明显地提高与其他富血管恶性肿瘤的鉴别诊断能力。     

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     

Nodular regenerative hyperplasia of the liver in Budd–Chiari syndrome: CT and MR features

We report the imaging findings of spiral computed tomography (CT), magnetic resonance (MR) imaging, and MR angiography in a patient with nodular regenerative hyperplasia of the liver associated with Budd–Chiari syndrome. Spiral CT showed multiple enhancing nodules during the hepatic arterial and portal venous phases. MR images showed multiple hyperintense nodules on T1-weighted images and hypointense or isointense nodules on T2-weighted images. MR angiography showed thrombotic occlusion of three hepatic veins, suggesting Budd–Chiari syndrome. Received: 25 June 1999/Revision accepted: 22 September 1999     

肝脏局灶性结节增生的影像表现

目的探讨肝脏局灶性结节增生的影像学表现和诊断价值.方法回顾性分析经病理证实的肝脏局灶性结节增生20例(25个病灶)的影像资料.结果 4/4个病灶CT平扫呈等或略低密度影;92%(22/24)病灶在CT增强扫描动脉期为均匀高密度或明显高密度;96%(23/24)病灶在门静脉期表现为高密度或略高密度;38%(8/21)病灶在延迟后平衡期扫描表现为高密度或略高密度,52%(11/21)为等密度;50%(12/24)病灶内有纤维分隔或瘢痕.60%(9/15)病灶在MR的T1WI为等信号,40%(6/15)为略低信号或低信号; 27%(4/15)病灶在T2WI为等信号,73%(11/15)为略高信号或高信号;15/15个病灶在动态增强扫描表现为动脉期明显均匀强化,门静脉期中等强化;11个病灶在延迟扫描呈高信号或略高信号;67% (10/15)病灶内可见纤维分隔或瘢痕.B超检查,65%(15/23)个病灶呈低回声,5个呈等回声或稍强回声病灶,3个呈高回声.结论影像检查能够正确诊断大部分肝脏局灶性结节增生病例,MRI显示其病理特征优于CT和B超.     

肝脏局灶性结节增生的螺旋CT和MRI对比研究

目的探讨肝脏局灶性结节增生（FNH）的CT和MRI表现及鉴别要点,提高影像诊断的准确率。方法回顾性分析13例经病理证实的肝脏FNH病人的CT和MRI表现。结果CT扫描检查10例,平扫9例病灶呈低密度,其中6例中央可见更低密度影,1例病灶呈稍高密度;增强扫描动脉期所有病灶均明显强化,呈均匀或不均匀密度;门脉期病灶呈稍高或等密度;6例病灶的中央瘢痕均延时强化。MRI检查11例,平扫病灶均呈T1WI稍低信号,T2WI稍高信号;增强扫描除中央瘢痕外,病灶动脉期明显强化,门脉期呈稍高或近等信号,延迟期呈近等信号,9例病灶的中央瘢痕延迟强化。结论CT和MRI对FNH的诊断具有特征性和准确性,二者结合能提高对FNH的诊断率。     

Intrahepatic splenosis: imaging features

We report a patient who presented with asymptomatic focal liver lesions and in whom a diagnosis of intrahepatic splenosis was made. This rare condition mostly occurs in patients who previously underwent splenic trauma or surgery. Magnetic resonance imaging (MRI) characteristics suggesting this diagnosis are described. The lesions were mainly hypointense on T1- and hyperintense on T2-weighted images. After administration of small iron oxide particles (SPIO-Endorem), the lesions remained slightly hyperintense relative to the hypointense liver parenchyma but showed a 50% loss in signal intensity. Knowledge of these MRI characteristics may avoid the use of surgical interventions to arrive at the correct diagnosis of these rare liver lesions. Received: 14 June 1999/Accepted: 14 July 1999     

肝局灶性结节增生的CT与MRI诊断

目的探讨肝局灶性结节增生（FNH）的CT和MRI表现,以提高FNH诊断准确性。方法回顾性分析20例经手术病理证实的24个FNH病灶的影像学资料,包括CT检查13例,MRI检查10例,其中3例同时做了CT及MRI检查。结果18例为单发病灶,2例为多发病灶。CT及MRI检出病灶数均为14个。CT平扫低密度9个,等密度5个。MRI平扫T1WI低信号10个,等信号4个;T2WI显示14个均呈高或稍高信号。所有病灶实质动脉期cT及MRI均明显强化。cT显示门脉期9个等密度,4个稍高密度,1个低密度;延迟期11个等密度,2个稍高密度,1个稍低密度。MRI显示门脉期高信号11个,等信号3个;延迟期高信号10个,等信号4个。CT多期扫描8个病灶伴有中央瘢痕,7个周边有扭曲、增粗血供,3个有假包膜。MRI多期扫描9个病灶伴有中央瘢痕,6个周边有扭曲、增粗血供,5个有假包膜。结论CT及MRI多期扫描可充分反映FNH的供血特点及病理特征,在FNH诊断与鉴别诊断中具有重要的价值。     

Fascioliasis: US, CT, and MRI findings with new observations

Background: The purpose of this study is to describe the ultrasonographic (US), computed tomographic (CT), and magnetic resonance imaging (MRI) findings in fascioliasis and to emphasize the impact of radiology in diagnosis. Methods: Radiologic findings in 23 consecutive patients with fascioliasis were prospectively recorded. All patients had at least one US and CT examination, and 10 of them were studied by MRI. All diagnoses were confirmed by serologic methods. In the first three cases, initial diagnosis was reached by microscopic demonstration of the parasites' eggs in bile obtained by US-guided gallbladder aspiration. Results: In the hepatic phase of fascioliasis, multiple, confluent, linear, tractlike, hypodense, nonenhancing hepatic lesions were detected by CT. On US, the parasites could be clearly identified in the gallbladder or common bile duct as floating and nonshadowing echogenic particles. MRI showed the lesions as hypo- or isointense on T1-weighted images and as hyperintense on T2-weighted images. Conclusions: CT findings in the hepatic phase and US findings in the biliary phase are characteristic of fascioliasis. Because clinical and laboratory findings of fascioliasis may easily be confused with several diseases, radiologists should be familiar with the specific radiologic findings of the disease to shorten the usual long-lasting diagnostic process. Received: 15 December 1999/Accepted: 26 January 2000     

肝脏局灶性结节样增生的MRI表现分析

目的 探讨肝脏局灶性结节样增生(FNH)的典型和不典型MRI表现.方法 回顾性分析15例经病理证实的FNH患者的MRI表现.结果 1)15例共检出16个病灶,其中14例为单发病灶,1例为2个病灶;2)MRI平扫14个病灶呈T1WI稍低、T2WI稍高信号,2个病灶呈等信号,13个病灶中央可见T2WI高信号的星状瘢痕;3)DWI上有13个病灶呈等信号,3个病灶呈略高信号;4)16个病灶动脉期明显强化,其中8个病灶周边见增粗、扭曲的供血动脉;13个病灶门脉期呈等信号,3个呈稍高信号;5)动脉期13个病灶中央瘢痕均未强化,延迟期10个病灶可见中央瘢痕强化,3个病灶中央瘢痕未见强化;6)1例病灶为外生型,门脉期可见假包膜.结论 典型FNH表现为增强后呈"快进慢出"强化、动脉期病灶周边见增粗和扭曲的供血动脉、延迟期可见中央瘢痕强化;不典型FNH表现为缺乏中央瘢痕或延迟期中央瘢痕不强化,多数结合平扫及DWI可明确诊断.     

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     

Imaging findings of Castleman disease of the abdomen and pelvis

BACKGROUND: The purpose of this study was to analyze the characteristic features of Castleman disease in the abdomen and pelvis as suggested by imaging findings in order to deepen the recognition and understanding of this rare disease. METHODS: A group of ten patients with pathologically proven Castleman disease in the abdomen (n = 9) and pelvis (n = 1) were included in this study. Patients were 18 approximately 56-year-old (mean = 40); seven of them were men and three were women. Imaging findings (CT&MRI, n = 4; only CT, n = 4; only MRI, n = 2) were retrospectively reviewed and correlated with clinical and pathologic findings. RESULTS: The lesions were divided into those with localized Castleman (n = 9) and disseminated Castleman (n = 1). The pathologic subtype of all nine cases of localized disease was hyaline vascular with six patients showing a solitary mass and three having a single dominant mass surrounded by small satellite nodules. On nonenhanced CT images, the lesions were manifested as homogeneous masses of soft tissue attenuation, which was isoattenuated relative to normal muscle. On MRI, the lesions were isointense or slightly hypointense compared with that of normal muscle on T1-weighted images and hyperintense on T2-weighted images. After intravenous injection of contrast media, most of the masses (7/9) showed marked enhancement and slow washout with the degree of enhancement approaching that of the large arteries. And in the interior of four cases of larger masses (>5 cm) was observed fissured and radial patterns in both low-density area on CT and low-signal area on MRI. These patterns were pathologically proved to be fibrous. The pathological subtype of a sole disseminated case was plasma-cell type, where imaging findings showed a lining of well defined, sharply enhanced soft-tissue nodules in retroperitoneal zone. CONCLUSION: Imaging findings of Castleman disease in the abdomen and pelvis are closely related to pathological type diagnosed. The characteristic features of localized and hyaline vascular type of Castleman disease include a solitary mass or a dominant mass surrounded with small satellite nodules, and high enhancement and slow washout with the degree of enhancement approaches that of large arteries. The presence of central areas of fibrosis of the larger tumors is one of the characteristic features of this disease.     

Small hepatocellular carcinoma: differentiation from adenomatous hyperplasia with color Doppler US and dynamic Gd-DTPA-enhanced MR imaging

Background: To investigate the usefulness of color Doppler ultrasound (US) and dynamic Gd-DTPA-enhanced magnetic resonance (MR) imaging in the differentiation of small hepatocellular carcinoma (HCC) and adenomatous hyperplasia (AH). Methods: Thirty-eight small (3 cm or less) nodular lesions (in 38 cirrhotic patients) with US features consistent with HCC underwent evaluation with color Doppler US and MR imaging. Breath-hold T1-weighted rapid acquisition spin echo MR sequence after bolus injection of 0.1 mmol/kg gadopentetate dimeglumine was used to evaluate dynamic enhancement. US-guided tissue-core percutaneous biopsy established the diagnosis: HCC in 28 cases and AH in 10. Results: Color signals with pulsatile or continuous Doppler spectrum were demonstrated in 19 of 28 HCCs (68%) but in none of the AHs. Although there was considerable overlap in signal intensity between HCC and AH on both unenhanced T1- and T2-weighted images, early enhancement on breath-hold T1-weighted images obtained 40 s after starting contrast administration was observed in 22 of 28 HCCs (79%) but in none of the AHs. In 26 of 28 HCCs (93%), pulsatile or continuous flow at color Doppler US, early enhancement at dynamic MR imaging, or both were observed. Conclusion: Findings with color Doppler US and dynamic Gd-DTPA-enhanced MR imaging enable a reliable distinction between small HCC and AH. Received: 8 August 1994/Accepted after revision: 27 January 1995     

肝脏局灶性结节增生的MRI表现与病理对照分析

目的：分析肝脏局灶性结节增生（FNH）的MRI表现和病理特点,探讨两者的相关性,提高FNH诊断的准确率。方法：回顾性分析23例（共28个病灶）经手术切除病理证实为FNH的MRI平扫及增强表现,与其病理特点进行对照。结果：25个病灶在平扫T1WI上呈等或稍低信号,T2WI上呈等或稍高信号,3个病灶在平扫T1WI及T2WI上均呈稍高信号,增强后所有28病灶动脉期可见明显强化,门脉期及延迟期呈稍高、等或稍低信号,其中12个病灶可见中心纤维瘢痕延迟强化。FNH组织病理上表现为富血供的实质性肿块,肿物内部组织较均匀,没有异型细胞,中心可见纤维瘢痕。结论：肝脏MRI平扫及增强检查能很好的反映FNH的组织病理及血供特点,能为FNH的诊断及鉴别诊断提供可靠证据。     

Fan-shaped hepatic parenchymal damage after ethanol injection therapy for hepatocellular carcinoma: MRI appearances

Background: T1- and T2-weighted magnetic resonance (MR) images frequently show fan-shaped areas of hypo- or hyperintensity in the hepatic parenchyma adjacent to a treated hepatocellular carcinoma after percutaneous ethanol injection (PEI) therapy. These areas correspond to abnormal contrast enhancement on serial dynamic MR images. The purpose of the present study was to describe the location, appearance, and frequency of these abnormalities because it is important to understand these entities for the correct assessment of therapeutic efficacy. Methods: MR imaging including a multisection dynamic study was performed in 20 consecutive patients with hepatocellular carcinoma treated with PEI therapy. We retrospectively evaluated the presence of fan-shaped hypointensities adjacent to treated tumors in the liver parenchyma on T1-weighted images and hyperintensities on T2-weighted images and corresponding fan-shaped contrast enhancement on both arterial-dominant and delayed-phase dynamic MR images. We review the location, appearance, and frequency of these findings, and we discuss the possible causes on the basis of pathologic examinations. Results: Seven (35%) of the 20 patients showed fan-shaped hyperintense areas adjacent to the treated tumors on T2-weighted images. These areas showed isointensity in five patients and hypointensity in two patients on T1-weighted images. Of these seven patients, one (14%) underwent the MR imaging within 1 month after the completion of PEI therapy, and six (86%) had it 2–9 months after the completion of PEI therapy (mean = 6 months). In all seven patients, fan-shaped hyperperfusion abnormalities corresponding to these areas of hyperintensity on T2-weighted images were seen on both arterial-dominant and delayed-phase dynamic MR images. Pathologically, the coagulative necrosis of the hepatocytes with sinusoidal dilatation and the restoration by the development of fibrous tissue were seen in these fan-shaped areas. Conclusion: The fan-shaped areas of abnormal intensity on T1- and T2-weighted images and contrast enhancement on dynamic MR images seem to be attributable to pathologic changes in the normal liver parenchyma induced by the toxic reaction of ethanol. Awareness of the occurrence of such abnormalities in the peripheral liver parenchyma adjacent to the treated tumor is important for the correct assessment of therapeutic efficacy. RID="ID="<e5>Correspondence to:</e5> T. Fujita Received: 24 June 1997/Accepted after revision: 22 October 1997     

MR imaging of intrahepatic cholangiocarcinoma

Background: The purpose of this study was to determine the magnetic resonance (MR) features of intrahepatic cholangiocarcinoma. Methods: MR imaging studies of seven cases of pathologically proven intrahepatic cholangiocarcinoma were retrospectively reviewed. Results: On MR images the tumors presented as a single mass (N = 5) or multiple nodules (N = 2), as welldelineated (N = 5) or ill-defined (N = 2), and as non-encapsulated (N = 7). Mean tumor diameter ranged from 6–14 cm (mean, 10 cm). On T1-weighted (TR/TE = 400–600/10–17 msec) images, the tumors were hypointense compared to the liver. The five tumors studied with dynamic MR imaging showed progressive centripetal filling-in after intravenous administration of a gadolinium chelate. On T2-weighted (TR/TE = 2000–2500/80–100 msec) images, all tumors were hyperintense compared to the liver; five were markedly hyperintense and two moderately hyperintense. Vascular encasement, bile duct dilatation within the tumor, and central scar were depicted on MR images in four, three, and two tumors respectively. Conclusion: The typical MR appearance of intrahepatic cholangiocarcinoma is a large well-delineated nonencapsulated tumor associated with intrahepatic venous encasement.     

Evaluation of Crohn disease activity with magnetic resonance imaging

Background: The purpose of this study was to assess the accuracy of magnetic resonance imaging (MRI) in evaluating Crohn disease (CD) activity. The intestinal inflammatory activity is usually present in patients under pharmacologic treatment, despite their clinical remission. Methods: Twenty patients with CD, all under pharmacologic treatment, were prospectively studied by MRI at 1.5 T as a periodic control. Positivity of three acute-phase reactants was considered an index of biologic activity (BA). T2-weighted, T2-weighted fat-suppressed turbo spin-echo, and breath-hold T1-weighted turbo field-echo sequences, before and after gadolinium intravenous injection, were obtained. A negative superparamagnetic contrast agent was orally administered. The following MRI parameters were qualitatively evaluated by three radiologists at the level of the affected bowel and compared with clinical data: wall thickness (WT), wall T2-weighted signal (T2W), wall contrast enhancement (WE), amount of fibrofatty proliferation (FP), and T2-weighted signal of fibrofatty proliferation on fat-suppressed images (T2FP). The κ coefficient of agreement was calculated. The Spearman rank correlation was used for the analysis of clinical and radiologic data. Results: Nineteen of 20 patients were in clinical remission (Crohn Disease Activity Index < 150). On the basis of laboratory tests, nine of 20 patients had biologically active disease. An excellent correlation was found between BA and WE, T2W, and T2FP (0.900, 0.927 and 0.961, respectively; p < 0.0001), and a lower correlation was found between BA and WT and between BA and FP (0.78 and 0.62). Excellent statistical correlation was also found between WE and T2W and between WE and T2FP (0.876 and 0.892). Conclusions: An excellent statistical correlation was found between biologically “active” disease and the following MRI parameters: wall gadolinium enhancement, wall hyperintensity on T2-weighted fat-suppressed images, and hyperintensity of fibrofatty proliferation on T2-weighted fat-suppressed images. Therefore, MRI can be valuable in assessing CD activity. Received: 22 January 1999/Revision accepted: 3 November 1999     

MR imaging of traumatic hepatic laceration: Evaluation and course of healing after surgery

Six patients with hepatic laceration underwent magnetic resonance imaging (MRI) at 0.5T. Acute hepatic laceration was slightly hypointense on T1-weighted spin-echo (SE) image, and hyperintense on T2- and proton-weighted SE images. Subacute laceration was heterogeneously intense on T1-weighted image and hyperintense on T2- and proton-weighted images. Consistent changes in signal intensity of postoperative hepatic laceration were observed. On Tl-weighted image, the signal intensity at first increased and then decreased from periphery to the center. On the T2- and proton-weighted images, the laceration was uniformly hyperintense relative to the liver prior to the appearance and growth of a hypointense ring at its periphery. The appearance of the above changes in signal intensity was also observed in postoperative recurrent hemorrhage. The postoperative biloma had none of the above changes in signal intensity. Our cases show that MRI is effective in the evaluation of hepatic laceration and in the assessment of the course of healing after operation.     

Hepatic involvement in hypereosinophilic syndrome: value of portal venous phase imaging

US, portal venous phase CT, and MRI-CSE (MRI with conventional spin-echo sequence) findings in three cases of hepatic involvement in hypereosinophilic syndrome are presented. These showed varied imaging findings, but portal venous phase CT showed multiple, poorly marginated, and hypodense hepatic lesions in all three cases. The result suggested that portal venous phase CT is the optimal method for depicting hepatic involvement. Received: 16 January 1996/Accepted: 30 October 1996     

原发性脑淋巴瘤的CT和MRI观察

目的:探讨原发性脑淋巴瘤的CT、MRI表现。材料与方法:回顾性分析25例未经治疗的原发性脑淋巴瘤的临床、病理及CT、MRI表现。结果:25例患者共计35个病灶,其中16例患者(19个病灶)同时作MRI检查,所有病灶CT平扫为等或稍高密度,T1WI为等、低信号,其中5个病灶伴局灶性高信号;12个病灶在T2WI上为等、低信号;14个病灶DWI为等、高信号。所有病灶均有增强,18个病灶为均匀增强。13例病理检查,病灶表现为瘤细胞密集、高核浆比,病灶内出血坏死少见。结论:免疫功能正常状态原发性脑淋巴瘤的CT、MR表现有一定特征性,但鉴别诊断仍需仔细谨慎。