螺旋CT强化方式在肝脏局灶性病变定性诊断中的价值

目的 探讨螺旋CT强化方式对肝脏局灶性病变的定性诊断价值. 方法 回顾性分析行肝脏螺旋CT多期增强扫描且发现局灶性病变的44例患者(54个病灶)的诊断结果,重点分析各类病灶的强化方式. 结果 (1)78%(14/18)的肝细胞癌表现为"快进快出"的强化方式,83%存在肝硬化背景,22%门脉可见癌栓;(2)9个肝血管瘤表现为"快进慢出",边缘明显强化逐渐向中心充填;(3)4例胆管细胞型肝癌表现为"慢进慢出",部分瘤灶内包埋胆管,周围可见扩张的肝内胆管;(4)14个肝转移瘤和5例肝脓肿表现为环形强化,肝转移瘤为周边程度不一的环形强化,肝脓肿则为单环或多环强化;(5)3例肝局灶性结节增生和1例肝细胞腺瘤表现为"快进慢出",2例局灶性结节增生存在中央瘢痕并延迟强化.结论螺旋CT强化方式能充分显示肝脏局灶性病变的血供特点,对定性诊断有较高的临床价值.     

Hepatic cavernous hemangioma: magnetic resonance imaging. Work in progress

Using a 0.35-T superconducting magnet and spin echo imaging, we prospectively evaluated 11 patients who had proved hepatic cavernous hemangioma. Magnetic resonance (MR) identified more lesions than either contrast-enhanced CT, or ultrasonography. The MR appearance was consistent; hemangiomas were homogeneous and generally isointense at short TR and TE intervals but were hyperintense at long TR intervals and greatly hyperintense at long TR and long TE intervals. However, the MR appearance of hemangioma was not specific; 2/14 other focal hepatic masses had similar features. The calculated relaxation times (T1, T2) were not useful in lesion characterization, although the intensity ratio of hemangioma to normal liver at the TR = 2.0 sec TE = 56 msec pulse sequence was useful in diagnosis since hemangiomas always had a ratio greater than 1.4.     

Hemangioma in the cirrhotic liver: diagnosis and natural history

PURPOSE: To investigate the natural history and diagnosis of cavernous hemangioma in the cirrhotic liver with computed tomography (CT) and magnetic resonance (MR) imaging. MATERIALS AND METHODS: Imaging and pathologic findings of 21 hemangiomas in 17 patients were retrospectively reviewed. CT of the liver was performed in all patients; MR imaging, in four. Cirrhosis was confirmed histologically in all patients, and the diagnosis of hemangioma was based on histopathologic findings (15 patients, 18 hemangiomas) or strict imaging criteria (two patients, three hemangiomas). Ten patients underwent imaging follow-up. The number, sizes, location, attenuation, pattern of enhancement, exophytic growth, presence of capsular retraction, and size stability were evaluated. RESULTS: Of the 21 hemangiomas, five were not detected at CT or MR imaging. Twelve (75%) of 16 hemangiomas were subcapsular, two (12%) of 16 demonstrated exophytic growth, 14 (87%) of 16 demonstrated nodular peripheral enhancement, and 16 (100%) of 16 were isoattenuating to blood vessels. At MR imaging, all five hemangiomas demonstrated nodular peripheral enhancement and hyperintensity on T2-weighted images. Seven lesions were smaller at follow-up, and five lesions developed retraction of the hepatic capsule. CONCLUSION: Even within the cirrhotic liver, larger hemangiomas can usually be diagnosed confidently with CT or MR imaging. With progressive cirrhosis, however, hemangiomas are likely to decrease in size, become more fibrotic, and are difficult to diagnose radiologically and pathologically.     

Computed tomography and sonography of cavernous hemangioma of the liver

Accuracy and limitations of computed tomography (CT) and sonography in the detection and diagnosis of cavernous hemangioma of the liver were analyzed in 39 cases. In 35 of 38 lesions examined by CT before and after bolus contrast enhancement, findings were dense contrast enhancement spreading in all directions on subsequent scans and/or density (other than capsule or septa) higher than normal hepatic parenchyma after 2 min. Lesions smaller than 1 cm were not detected. Misregistration in sequential scans prevented diagnosis of three of nine lesions smaller than 2 cm. Sonography revealed various patterns of mass, but in the smaller lesions, an extremely hyperechoic pattern was dominant. The contributions of CT and sonography depend on the size of the lesions.     

螺旋CT双期或三期扫描对肝脏占位性病变的诊断

目的：分析肝脏螺旋CT双期或三期扫描表现，探讨其对原发性肝癌、肝转移瘤、肝血管瘤的诊断及鉴别诊断的意义。方法：经临床证实25例，均作螺旋CT平扫、动脉期、门脉期及部分平衡期和延迟期扫描，并分析螺旋CT多期扫描表现。结果：原发性肝癌动脉期明显强化而肝脏无强化，形成鲜明的对比，门脉期呈相对低密度或恢复到平扫时表现。肝血管瘤CT特征为动脉期呈边缘性环状、结节样强化，门脉期病灶边缘强化向中心强化并充满病灶呈高密度，平衡期呈等密度或低密度肝转移瘤表现多样化，周边强化或不均匀强化或不强化。结论：螺旋CT双期或三期扫描已作为对肝脏占位性病变的主要检查方法，并作为常规。     

Hepatic cavernous hemangioma in patients at high risk for liver cancer

Cavernous hemangioma of the liver occurring in patients at high risk for liver cancer has been reviewed. Twenty-four patients with hemangioma were encountered during the past 4 years. Five lesions over 3 cm in diameter were correctly diagnosed with enhanced CT alone. Definite CT findings were however obtained in only 6 out of 19 lesions smaller than 3 cm in diameter. Ultrasonography was the most sensitive method for picking up small liver tumors even when compared with angiography, but the findings were non-specific (an echogenic mass was noted in 14 of the 19 lesions). Magnetic resonance imaging (MRI) had almost the same sensitivity as ultrasound in detecting small hemangiomas, and a prolonged T2 was highly suggestive of the diagnosis (T2 over 80 ms in 8 of 11 lesions). The results suggest that combined use of non-invasive diagnostic modalities has sufficient reliability to make a diagnosis of cavernous hemangioma even in small hepatic lesions, in patients at high risk for liver cancer.     

Transcatheter arterial chemoembolization in patients with hepatocellular carcinoma and coexisting hepatic cavernous hemangioma

We investigated the consequence of repeated transcatheter arterial chemoembolization (TACE) for coexisting small hepatic hemangioma in the treatment of patients with hepatocellular carcinomas and describe the imaging features of embolized hemangioma on the follow-up Lipiodol CT and MR. Six of 431 patients with biopsy-confirmed hepatocellular carcinomas, who underwent TACE, also had seven small hepatic cavernous hemangiomas (0.8∼2.3 cm) in the same area of embolization. All six patients underwent repeated TACE All lesions were evaluated with CT and/or MR for the post-treatment follow-up. The outcomes and imaging features of these embolized hemangiomas were reviewed for the change of tumor size, Lipiodol deposition, enhancing pattern as well as embolization complications. Six of the seven hemangiomas did not depict changes in the size or enhancement pattern without being ablated. One hemangioma showed a decrease in size, but still persisted after TACE. All of the hemangiomas showed Lipiodol deposition for 2∼15 months, in which five hemangiomas depicted irregular rim patterns. There is no complication caused by the procedures. The differentiation of small hepatic hemangiomas from viable HCC is important in the post-TACE follow-up to avoid unnecessary repeated embolization.     

肝海绵状血管瘤25例CT征象分析

目的探讨肝血管瘤的CT表现,提高对肝血管瘤的认识。方法对25例患者行CT平扫加增强扫描,对其影像进行观察分析。结果大多数肝血管瘤CT平扫表现为肝内单发或多发圆形或椭圆形低密度影,增强扫描表现为早期结节样、环形、斑片状强化,随时间进展呈向心性强化,部分直至完全充填,然后强化逐步减退,表现为快进慢出特征。结论肝血管瘤CT表现大多数有典型特点,CT平扫及增强扫描是诊断肝血管瘤的有效方法。     

肝脏血管平滑肌脂肪瘤的影像诊断

目的 研究肝血管平滑肌脂肪瘤的影像特征及其病理基础,以减少对该病的误诊。材料与方法 3例肝血管平滑肌脂肪瘤均经B超和CT平扫及增强扫描,1例加做MRI检查,3例经B超及CT检查显示5个病灶。 2例3个病灶经病理诊断,其中2个病灶术前误诊为肝癌和肝血管瘤;另1例肝脏含脂肪的肿块伴有肾脏多发病变及结节硬化。结果 在影像上肝血管平滑肌脂肪瘤具有特征性的表现：（1）瘤内脂肪,在B超上,表现为强回声区;CT上,呈明显低密度;MR T1WI上呈高信号。（2）肿瘤在肝动脉期明显强化,门静脉期中度强化。结论 肝血管平滑肌脂肪瘤易误诊为其他肝病,但实际上,一些影像学表现能反映肝血管平滑肌脂肪瘤的组织成分,有助于术前正确诊断。     

肝脏占位性病变的CT诊断及鉴别诊断

目的探讨CT对肝脏占位性病变的诊断及鉴别诊断的价值。方法收集310例肝脏占位性病变(包括原发性肝癌72例,肝转移癌58例,肝血管瘤35例,肝脓肿21例,肝包虫病58例,肝囊肿66例)的临床和CT资料,分析肝脏占位病变的部位、数目、边界以及增强后的CT表现。结果肝脏占位性病变表现为单发或多发低密度灶,边界清或不清,增强后可有程度不一的强化或不强化。本组肝脏占位性病变各自均有典型的CT征象,大多能作出定性诊断。结论CT对肝脏占位性病变的诊断及鉴别诊断有很大的价值。     

脑实质内海绵状血管瘤的CT和MRI诊断

目的 探讨脑实质内海绵状血管瘤(CA)的CT和MRI表现，以提高对本病的认识。资料与方法 回顾性分析经手术病理证实的CAl4例。12例行CT平扫，10例行CT增强扫描；10例行MM检查，6例行Gd—DTPA增强扫描；9例同时行CT和MRI检查。结果 CA可发生于脑内任何部位，以单发病灶多见。12例CT平扫发现16个病灶，全部病灶均呈高密度或稍高密度，7个病灶可见钙化；10例CT增强扫描发现病灶14个，9个病灶无强化，5个病灶呈轻度强化。10例MRI检查发现13个病灶，3个在T1WI上是等信号，10个为高信号；在T2WI上全部病灶为高低混杂信号，其中9个病灶周围伴有环形低信号，大多数病灶周围无水肿带，无占位效应。结论 CA具有较典型的影像学表现，CT和MRI对病变的诊断具有重要意义，且MRI优于CT。正确诊断有赖于结合临床资料和影像学征象的综合分析。     

Patterns of contrast enhancement of benign and malignant hepatic neoplasms during bolus dynamic and delayed CT

Bolus dynamic and delayed computed tomographic (CT) scans of the liver were evaluated in 43 patients with 54 hepatic hemangiomas and 111 patients with primary or secondary malignant hepatic neoplasms. Twelve patterns of contrast enhancement were recognized during the bolus dynamic phase and delayed scanning. A "typical" CT pattern for hemangiomas (present in 29 of 54 hemangiomas [53.7%]) was established: (a) diminished attenuation prior to intravenous contrast medium administration (excluding lesions arising in a liver with diffuse fatty infiltration), (b) peripheral contrast enhancement during the bolus dynamic phase, and (c) complete isodense fill-in on delayed scan images. Using these criteria, we distinguished hemangiomas from malignant neoplasms in most patients. Only one of 63 (1.6%) malignant neoplasms manifested these typical CT criteria of hemangioma. There is an 86% chance that a lesion with the typical CT appearance of hemangioma is actually a hemangioma, even when found in a patient with a known nonhepatic primary neoplasm.     

儿童肝脏血管瘤的介入治疗方法及疗效的初步探讨

目的探索儿童肝脏血管瘤的介入治疗方法及疗效。 方法回顾性分析我院31例实施肝脏血管瘤介入治疗患者的临床资料。年龄6 d至9岁；先天型肝脏血管瘤26例，婴儿型肝脏血管瘤5例；肝脏多发病变5例，单发病变26例。所有患者均接受CT平扫、CT增强扫描以及肝脏血管瘤硬化栓塞术。依据患者治疗前后CT影像学表现，分析肝脏血管瘤硬化栓塞术对不同分型患者治疗疗效。采用配对样本t检验分别比较婴儿型及先天型肝血管瘤介入治疗术前、术后体积差异。 结果23例接受单次介入治疗，6例接受2次介入治疗，2例接受3次介入治疗。26例患儿接受随访，包括先天型肝血管瘤23例，婴儿型肝血管瘤3例。11例瘤体完全消失，患儿完全康复，15例瘤体部分缩小（4例缩小70%以上，效果显著；6例缩小30%~50%，部分有效；5例缩小低于30%，效果欠佳）。先天型肝血管瘤术前、术后平均体积分别为（161.86 ± 21.40）cm³、（41.46 ± 9.73）cm³，婴儿型肝血管瘤术前、术后平均体积分别为（22.73 ± 1.92）cm³、（11.18 ± 3.18）cm³，术前、术后体积差异均具有统计学意义（P < 0.001）。 结论肝脏血管瘤硬化栓塞术是一种安全、有效的微创治疗方法，对儿童肝脏血管瘤治疗效果较好，且术前分型是儿童肝脏血管瘤介入治疗疗效的重要因素。     

Thin-section CT of severe acute respiratory syndrome: evaluation of 73 patients exposed to or with the disease

PURPOSE: To retrospectively analyze the thin-section computed tomographic (CT) features in patients with severe acute respiratory syndrome (SARS) at the authors' institution. MATERIALS AND METHODS: From March 11, 2003, to April 2, 2003, 74 patients with symptoms and signs suggestive of SARS underwent CT of the thorax; all underwent thin-section CT except for one patient who underwent conventional CT. Group 1 (n = 23) patients had symptoms of SARS in keeping with criteria from the Centers for Disease Control and Prevention and a positive chest radiograph. Group 2 (n = 17) patients had a high clinical suspicion of SARS but a normal radiograph. Group 3 (n = 34) patients had minor symptoms and a normal chest radiograph. The thin-section CT images were analyzed for ground-glass opacification or consolidation, lesion size in each lung segment, peripheral or central location, interstitial thickening, and other abnormalities. RESULTS: Thin-section CT scans were abnormal only for patients in groups 1 and 2. The patient with only conventional CT scans was in group 3; scans for group 3 patients were normal. Affected segments were predominantly in the lower lobes (91 of 149 affected segments). Common findings included ground-glass opacification, sometimes with consolidation, and interlobular septal and intralobular interstitial thickening. The size of each lesion and the total number of segments involved were smaller in group 2 patients. A majority of patients in group 1 (14 of 23) had mixed central and peripheral lesions. In group 2, however, peripheral lesions were more common (10 of 17). In both groups, a purely central lesion was uncommon (one of 23 in group 1 and two of 17 in group 2). CONCLUSION: Common thin-section CT features of SARS are ground-glass opacification and lower lobe and peripheral distribution.     

Preoperative evaluation of hepatocellular carcinoma: combined use of CT with arterial portography and hepatic arteriography

OBJECTIVE: This study was undertaken to determine the usefulness of combined CT during arterial portography and CT hepatic arteriography in the preoperative evaluation of patients with known or suspected hepatocellular carcinoma and to describe the findings on CT during arterial portography and CT hepatic arteriography by which hepatocellular carcinomas may be differentiated from pseudolesions. SUBJECTS AND METHODS: This study included 137 patients who underwent combined CT during arterial portography and CT hepatic arteriography for the preoperative evaluation of known or suspected hepatocellular carcinoma. The images were prospectively evaluated to identify focal hepatic lesions and their differential diagnoses (hepatocellular carcinoma versus pseudolesion). We assessed the diagnostic accuracy of our prospective interpretation by comparing the interpretations with the results of histopathology or follow-up imaging. We also retrospectively analyzed imaging features seen on CT during arterial portography and CT hepatic arteriography-the size, shape, and location of the lesion within the liver; attenuation of the lesion; and opacification of the peripheral portal vein branches on CT hepatic arteriography. RESULTS: One hundred and forty-nine hepatocellular carcinomas (75 lesions confirmed at histopathology and 74 lesions on follow-up imaging) were found in 120 patients, and 104 pseudolesions (15 lesions confirmed at histopathology and 89 lesions on follow-up imaging) were found in 91 patients. The sensitivity of our prospective interpretations was 98.7%, and the specificity of our prospective interpretations was 90.4%. Our positive and negative predictive values were 93.6% and 97.9%, respectively. We found that hepatocellular carcinomas were larger, more frequently nodular, and more likely to be located intraparenchymally than were the pseudolesions (p < 0.01). Opacification of the peripheral portal vein branches on CT hepatic arteriography was detected in 36 pseudolesions (34.6%) but in none of the hepatocellular carcinomas (p < 0.01). CONCLUSION: Combining CT during arterial portography and CT hepatic arteriography is useful for the preoperative evaluation of patients with known or suspected hepatocellular carcinoma. Familiarity with the imaging features of hepatocellular carcinomas and pseudolesions can help in the accurate differentiation of hepatocellular carcinomas from pseudolesions.     

Computed tomography in the diagnosis of cavernous hemangioma of the liver

Computed tomography (CT), using a sequential timed scanning technique, was performed on six patients with hepatic cavernous hemangiomas. Initial examination shows a moderately homogeneous circumscribed area with reduced attenuation values. Serial scans after injection of a bolus of contrast material show early peripheral opacification while the central part of the lesion retains low attenuation values for several minutes. Later scans demonstrate a variable degree of "filling in" of the central part of the hemangioma. If the characteristic appearance of this lesion is recognized, confusion with other ominous lesions and biopsy can be avoided. Because of limited experience, the described pattern may not be absolutely pathognomonic for hemangioma, so angiography is currently advised to confirm the diagnosis.     

Small nodules (1-2 cm) in liver cirrhosis: characterization with contrast-enhanced ultrasound

Objective

To determine the diagnostic efficacy of arterial phase contrast-enhanced ultrasound (CEUS) for characterizing small hepatic nodules (1-2 cm) in patients with high-risk for hepatocellular carcinoma (HCC).

Materials and methods

Over 12 months, CEUS was performed in 59 patients at high-risk for HCC with small hepatic nodules (1-2 cm; mean, 1.5 cm). Based only on arterial phase (<45 s) vascular intensity and pattern, lesions were prospectively diagnosed as HCC if there was hypervascularity without known features of hemangioma. The diagnosis of HCC was made regardless of the presence or absence of washout. Verification of diagnosis was made by liver transplantation (n = 13), biopsy (n = 12), resection (n = 3) or clinical and imaging follow-up for at least 12 months (n = 31).

Results

At of the time of CEUS, the 59 nodules were diagnosed as HCC in 26 and benign lesions in 33, including 20 regenerative/dysplastic nodules (RN/DN), 11 hemangiomas, and 2 focal fat sparing. All 26 nodules with arterial phase hypervascularity without hemangioma-like features were HCC. However, CEUS misdiagnosed HCC as RN/DN in 4 cases with arterial iso- (n = 3) or hypovascularity (n = 1). CEUS correctly diagnosed all 11 hemangiomas. The sensitivity, specificity, and accuracy of CEUS for diagnosing HCC were 86.7, 100, and 93.2%.

Conclusions

Arterial phase vascular intensity and pattern of CEUS are highly accurate for the diagnosis of small (1-2 cm) HCC and hemangioma in liver cirrhosis. On CEUS, arterial phase hypervascularity without a hemangioma-pattern alone may be sufficient for diagnosis of small HCC. Infrequent iso/hypovascular HCC may erroneously suggest RN/DN necessitating biopsy or close follow-up.     

Dilatation of the intrahepatic bile ducts associated with benign liver lesions: an unusual finding

In three patients presenting different types of liver lesions, including isolated cyst, focal nodular hyperplasia (FNH), and hemangioma, intrahepatic bile duct dilatation was observed on US and CT. Final diagnosis was obtained by surgery in two cases (cyst and FNH) and by 1-year follow-up in one patient presenting an isolated hemangioma. The only common characteristic in our three cases was that lesions were present in segment four according to Couinaud's classification, at the level of the transverse fissure, suggesting that a space-occupying lesion at this site may cause compression of the common hepatic duct and right or left intrahepatic bile ducts. Our report indicates that compression may occur even with lesion of moderate size (35–40 mm in diameter). A benign liver lesion may cause a bile duct dilatation, particularly if located in segment 4, close to the hilum. Awareness of this possibility is important to avoid unnecessary invasive diagnostic procedures, particularly when all imaging criteria are consistent with a benign lesion. Electronic Publication     

颅内海绵状血管瘤的CT和MRI诊断

目的:探讨脑内与脑外海绵状血管瘤的CT和MRI表现及诊断价值.方法:搜集45例颅内海绵状血管瘤的CT和MRI影像资料进行分析,MRI检查45例,CT检查30例,其中脑内型海绵状血管瘤42例,脑外型海绵状血管瘤3例,均经手术病理证实.结果:脑内型海绵状血管瘤可位于脑内任何部位,单发病灶多见,无明显占位效应,周围无或轻度水肿.CT检查的全部病例呈稍高及混杂密度影27例,增强扫描大都无强化;MRI检查T2 WI表现为"桑葚状"混杂高信号,周围有云絮状低信号环,增强后病灶仅少数轻度强化.脑外型病灶位于中颅窝鞍旁,MRI呈类似哑铃形或类圆形较均匀的稍长T1明显长T2信号,增强扫描呈明显均匀强化.结论:脑内与脑外型海绵状血管瘤的CT和MRI表现具有一定特征,MRI优于CT像,特别是MRI的T2 WI像有助于明确诊断.     

Hepatic hemangioma: dynamic bolus CT

Forty-seven patients with 58 hepatic hemangiomas were studied prospectively with a dynamic bolus CT protocol (single-level or incremental scans) that included precontrast scans, rapid-sequence scanning during the IV bolus injection of 150 ml of 60% contrast agent, and delayed scans taken as long as 60 min after contrast. Three CT criteria are believed to be necessary to make a specific diagnosis of hemangioma: lesion with diminished attenuation on precontrast scan; peripheral contrast enhancement during the dynamic bolus phase of scanning; and complete isodense fill-in on delayed scans obtained up to 60 min after contrast. These CT criteria were seen in only 32 (55%) of 58 hemangiomas, making CT a relatively poor imaging technique for diagnosis.