Multidetector-row computed tomography of focal liver lesions treated by radiofrequency ablation: spectrum of findings at long-term follow-up

OBJECTIVE: To assess serial changes in liver tumors after percutaneous radiofrequency ablation at follow-up multidetector-row computed tomography. MATERIALS AND METHODS: Forty patients with 65 malignant lesions underwent multidetector-row computed tomography immediately, 1 month and every 3 months, up to a maximum of 15 months after radiofrequency ablation. The computed tomography (CT) appearance of the treated lesions (non-enhanced attenuation, enhancement pattern, shape and size) was assessed at each follow-up. The relationship between each CT finding and the treatment outcome was evaluated by chi2 test (P < 0.05). RESULTS: No significant differences were found in lesion shape and in non-enhanced CT attenuation between successfully and unsuccessfully treated lesions, whereas over time change of lesion size was significantly different. The no enhancement and nodular enhancement pattern prevalence was significantly (P < 0.0001) different between successfully and unsuccessfully treated lesions, whereas non-nodular enhancement pattern did not show any relationship with the treatment outcome. CONCLUSIONS: Lesion size increase and nodular enhancement pattern resulted significantly related to the treatment failure.     

Effects of prostaglandin E(1) injection through the superior mesenteric artery on the hemodynamics of hepatocellular carcinoma.

OBJECTIVE: The purpose of our study was to assess the effects of portal blood flow on contrast enhancement in hepatocellular carcinoma lesions on CT hepatic arteriography. SUBJECTS AND METHODS: We examined 43 tumors in 39 patients who simultaneously underwent CT during arterial portography and CT hepatic arteriography for examination of liver tumors and then CT hepatic arteriography with prostaglandin E(1) injection via the superior mesenteric artery. All lesions pathologically confirmed to be hepatocellular carcinomas exhibited portal perfusion defects on CT during arterial portography. Changes in CT attenuation, size, and shape of liver tumors visualized on CT hepatic arteriography after intraarterial injection of prostaglandin E(1) were studied. In addition, changes in CT attenuation of the liver parenchyma surrounding the tumor were measured. RESULTS: The CT attenuation increased significantly after injection of prostaglandin E(1) in 91% (39/43) of the lesions (mean increase from 176.4 to 206.6 H; p = 0.0006, paired t test). The size and shape of the enhanced area generally did not change. The CT attenuation of the liver parenchyma surrounding each liver tumor significantly decreased in 58% (25/43) of the hepatocellular carcinoma lesions (mean decrease from 94.8 to 92.0 H; p = 0.0166, paired t test) and lesion conspicuity increased in 91% (39/43) of the tumors. CONCLUSION: Lesion conspicuity on CT hepatic arteriography between hepatocellular carcinoma and the surrounding liver parenchyma increased because of greater portal perfusion after the prostaglandin E(1) injection.     

Hepatocellular carcinoma treated with percutaneous radio-frequency ablation: evaluation with follow-up multiphase helical CT.

PURPOSE: To determine serial changes in hepatocellular carcinomas (HCCs) treated with percutaneous radio-frequency (RF) ablation at long-term follow-up multiphase helical computed tomography (CT). MATERIALS AND METHODS: There were 43 nodular HCCs in 40 patients at follow-up CT performed not less than 12 months after RF ablation. All patients underwent follow-up multiphase helical CT immediately, 1 month, and then every 3 months after percutaneous RF ablation. The serial changes in attenuation, enhancement pattern, shape, other findings, and volume of the ablated lesions were analyzed at follow-up CT. RESULTS: Thirty-eight (88%) of 43 ablated lesions were of low attenuation, with absence of contrast material enhancement at immediate and 1-month follow-up CT, which is suggestive of successful treatment. The remaining five lesions (12%) showed peripheral nodular enhancement, suggesting residual viable tumor. Compared with volume changes at immediate follow-up CT, the mean percentages of volume change at 1, 4, 10, 16, and 19 months were 79%, 50%, 27%, 11%, and 6%, respectively. Of 43 ablated lesions, 24 (56%) were mostly round at immediate CT and remained unchanged at subsequent follow-up CT. Peripheral rim enhancement was seen in 34 (79%) of 43 lesions at immediate CT but resolved in all 34 lesions at 1-month follow-up CT. Other associated findings included iatrogenic arteriovenous shunt in 10 patients, perihepatic hemorrhage in three, and pneumothorax in one. CONCLUSION: Follow-up multiphase helical CT of HCCs treated with percutaneous RF ablation showed variable findings in the treated lesions and surrounding liver parenchyma.     

Solid organizing hepatic abscesses mimic hepatic tumor: Multiphasic computed tomography and magnetic resonance imaging findings with histopathologic correlation

OBJECTIVE: To describe the computed tomography (CT) and magnetic resonance imaging (MRI) findings of solid organizing hepatic abscesses and correlate them with the pathologic findings. METHODS: Ten patients with 10 pathologically proven solid organizing hepatic abscesses who underwent 3-phase CT (n = 10) or MRI (n = 7) were enrolled in this study. Images were retrospectively analyzed by consensus of 2 radiologists for attenuation (signal intensity), shape, and margin of the lesions as well as for their enhancement patterns. Their imaging findings were correlated with their pathologic findings. RESULTS: The main imaging finding on CT or MRI was the well-defined target appearance of a central enhancing area with a low-attenuation (signal intensity) rim on arterial and portal phases. On the delayed phase, most of lesions showed slightly low attenuation (signal intensity) with an enhancing rim, and 1 showed diffuse enhancement. Pathologically, the central areas and peripheral rims corresponded to granulation tissue and fibrosis, respectively. Nine lesions demonstrated a tiny necrotic cystic portion in the center. CONCLUSION: The target appearance of solid organizing hepatic abscesses on CT and MRI can be helpful in differentiating them from other focal liver lesions. These imaging findings are well correlated with the pathologic findings.     

1999 ARRS Executive Council Award. Contrast-enhanced CT of small hypovascular hepatic tumors: effect of lesion enhancement on conspicuity in rabbits. American Roentgen Ray Society

OBJECTIVE: The purpose of this study was to evaluate the effect of lesion enhancement on the conspicuity of small hypovascular hepatic tumors in an animal model. MATERIALS AND METHODS: Seven VX2 hepatic tumors in five rabbits were imaged. Dynamic contrast-enhanced CT was performed at a single level centered over the lesions at 5-sec intervals for 119 sec after injection of 2 ml/kg i.v. contrast material at 2 ml/sec. Attenuation was measured over time within regions of interest in the tumor and normal liver, aorta, inferior vena cava, and portal vein. Lesion conspicuity, defined as the difference between the attenuation of the uninvolved liver and neoplasm, was calculated. RESULTS: The mean diameter of the tumors on CT was 10 mm (range, 6-15 mm). The tumors appeared as low-attenuation lesions with progressive enhancement during the arterial phase and early portal phase. Peak mean lesion attenuation was 60 +/- 27 H (enhancement, 23 H) at 64 sec. Peak mean lesion conspicuity was 80 +/- 18 H at 39 sec, occurring 10 sec before the peak mean hepatic attenuation of 135 +/- 15 H (enhancement, 67 H) at 49 sec. Relative lesion conspicuity paralleled relative enhancement of the liver throughout the imaging period. CONCLUSION: Although low-level tumor enhancement during the arterial phase and early portal phase reduced the conspicuity of small hypovascular tumors in this animal model, our results support the use of maximum liver enhancement as a marker for peak lesion conspicuity.     

MR imaging of the kidneys after laparoscopic cryoablation

OBJECTIVE: We describe the MR imaging findings of patients who underwent laparoscopic renal lesion cryoablation. MATERIALS AND METHODS: Twenty-one patients (men, 11; women, 10; age range, 36-84 years; average age, 65.5 years; SD, 11.9) with 23 small renal masses (< or =4 cm) underwent laparoscopic renal lesion cryoablation. Twenty patients (22 masses) underwent follow-up MR imaging on the first day after surgery, 12 (13 masses) at 1 month, 16 (18 masses) at 3 months, 14 (15 masses) at 6 months, and 12 (12 masses) at 12 months. Three radiologists retrospectively reviewed MR images for the signal intensity, characteristics, and size of cryolesions. CT-guided needle biopsy was performed 6 months after cryoablation (18 patients) and no evidence of malignancy was discovered. RESULTS: Including all lesions at all times on T1-weighted images, cryolesion signal intensity was isointense to renal parenchyma (47/76, 61.8%) or isointense with hyper- or hypointense foci (7/76, 9.2%). On T2-weighted images, almost all lesions (72/76, 94.7%) were isointense or hypointense, and there was a hypointense rim between the cryolesion and renal parenchyma in 38.2% of lesions (29/76). A thin peripheral rim of enhancement was noted in 19.7% (14/74) of lesions. Cryolesions decreased in size an average of 61.5% (SD, 22.82; n = 12) at 1 month, 78.7% (SD, 13.5; n = 17) at 3 months, 83.5% (SD, 24.3; n = 15) at 6 months, and 94.2% (SD, 8.1; n = 11) at 1 year after cryoablation (one patient was not scanned 1 day after cryoablation and was not included in our calculations). CONCLUSION: After renal cryoablation, MR imaging revealed common signal characteristics such as low-signal-intensity rims on T2-weighted images, enhancement patterns such as thin peripheral rims, and interval size changes.     

The value of CT scanning and percutaneous fine needle aspiration of adrenal masses in biopsy-proven lung cancer.

Pre-operative CT scans of 546 patients with biopsy-proven primary bronchial carcinoma were reviewed. Twenty-two patients had a solid adrenal tumour (2 bilateral). Sixteen underwent percutaneous fine needle aspiration (FNA). Malignant cells were aspirated in five, eight revealed benign cells and in three cases there was insufficient material for diagnostic purposes. Six patients did not undergo FNA, four of these were considered to have benign adenomas on CT. This was confirmed by the unchanged CT image at more than 21 months follow-up. The five subjects with FNA-proven metastases died at a median of 14 months (range 3-24 months). All five would have been regarded as operable on their staging chest CT scan. Five patients with a negative biopsy underwent surgery, two died of metastases at 6 and 11 months respectively and one died of post-operative complications. The other two have unchanged adrenal lesions on CT at 9 months and 25 months. The CT appearances of these lesions were analysed. Well defined, low attenuation lesions which had a smooth attenuation rim or only involved part of the gland were benign and the survivors had unchanged CT appearances at follow-up (six lesions in five patients). Of these four lesions were less than or equal to 2 cm in diameter. Low attenuation lesions without a rim were malignant (n = 2). These latter both measured more than 2 cm in diameter. The CT appearances of many adrenal lesions were insufficiently distinctive to exclude malignancy and biopsy was necessary to establish a diagnosis.     

Epithelioid hemangioendothelioma of the liver: imaging findings with pathologic correlation.

Hepatic epithelioid hemangioendothelioma is a rare malignant neoplasm that has nonspecific clinical signs and symptoms and can be difficult to diagnose on the basis of biopsy results. Radiologists may suggest the diagnosis of this slowly progressive neoplasm by recognizing its characteristic radiologic features. We correlated images from CT (13), sonography (nine), and MR (six) with pathologic findings in resected whole livers (eight) and biopsy specimens (five) from 13 patients 25-58 years old. Gross pathologic examination showed a repetitive pattern of multiple solid tumor nodules, in a predominantly peripheral distribution, with coalescence as individual nodules exceeded 4 cm. Tumor nodules had a hyperemic rim. Lesions adjacent to the capsule often produced capsular retraction. These findings correlated well with imaging findings. On CT, the lesions were of low attenuation, peripherally based, and with capsular retraction or flattening in nine (69%) of 13 patients. Unenhanced CT scans showed superior conspicuity over contrast-enhanced CT scans (9/13, 69%) and showed the extent of lesions more accurately in all cases (13/13, 100%). In nine patients, lesions had a peripheral enhancement pattern of alternating attenuation values correlating with the hyperemic rim at pathologic evaluation. On sonograms, the tumors were solid and predominantly hypoechoic. On MR, tumor signal was low on T1-weighted and high on T2-weighted images, with a low-signal halo present around many of the lesions. CT, sonographic, or MR findings of coalescent peripheral hepatic masses with capsular retraction are highly suggestive of hepatic epithelioid hemangioendothelioma.     

Focal peliosis hepatis as a mimicker of hepatic tumors: radiological-pathological correlation

OBJECTIVE: To retrospectively evaluate the radiological findings in patients with focal peliosis hepatis and to correlate them with pathological findings. METHODS: Eight patients with pathologically proven peliosis hepatis underwent ultrasonography (n = 6), computed tomography (CT; n =8), and/or magnetic resonance imaging (MRI; n = 3). Two radiologists analyzed the images for the size, margin, echogenicity, presence of posterior acoustic enhancement, and enhancement pattern of the lesion. The enhancement patterns on CT or MRI were correlated with the pathological findings. RESULTS: The average lesion size was 1.9 cm. On ultrasonography, 4 lesions were ill defined and low echoic compared with the hepatic parenchyma. Two lesions showed posterior acoustic enhancement. In 4 lesions, centripetal enhancement was observed on dynamic CT images. Two lesions showed homogeneously high and 2 showed persistently low enhancement patterns. On dynamic MR phases, 2 lesions showed strong and persistent enhancement. In 1 lesion, MR showed slow centripetal enhancement. In the 3 patients who showed a homogeneously high enhancement pattern on dynamic CT or MRI, microscopic examination demonstrated that the dilated sinusoids were filled with fresh blood cells. On the contrary, in 5 patients who showed a centripetal or persistently low enhancement pattern, their dilated sinusoids were filled with old stagnated blood. CONCLUSIONS: Focal peliosis hepatis showed various enhancement patterns on contrast-enhanced CT and MRI, depending on the histopathologic findings.     

Frequency of benign hepatic lesions incidentally detected with contrast-enhanced thin-section portal venous phase spiral CT

PURPOSE: To evaluate the frequency of benign focal hepatic lesions incidentally detected at contrast-enhanced thin-section portal venous phase spiral CT. MATERIAL AND METHODS: Between January 1998 and February 1999, contrast-enhanced hepatic spiral CT examinations were performed in 1,892 patients. Out of these, only 100 patients fulfilled the following inclusion criteria: No underlying malignant disease, no liver cirrhosis, no suspected or known focal liver lesions. Standardized spiral CT parameters were applied. All CT studies were reviewed retrospectively by one radiologist. Any focal lesion was recorded and classified. Lesion size and number were noted. RESULTS: A total of 108 hepatic lesions were reported in 33 out of 100 patients (80 cysts; 18 hemangiomas; 3 focal fatty infiltrations; 2 focal non-tumorous perfusion defects; 1 calcification; and 4 non-classified lesions). The average lesion size was 9.4 mm (< or =5 mm: n=40; 6-10 mm: n=30; 11-15 mm: n=28; >15 mm: n=10). CONCLUSION: Benign liver lesions are probably a frequent incidental finding at abdominal spiral CT.     

Computed tomography appearance of high-dose-irradiated hepatic parenchyma surrounding small tumors after stereotactic radiotherapy

INTRODUCTION: The purpose of this study was to demonstrate the computed tomography (CT) appearance of high-dose-irradiated hepatic parenchyma surrounding small tumors after stereotactic radiotherapy (SRT). MATERIALS AND METHODS: Thirteen patients were enrolled between September 1999 and August 2001. We treated 15 lesions [six hepatocellular carcinomas (HCC) and nine liver metastases] with SRT using a linear accelerator. We used two SRT protocols of 45 Gy/3 fractions or 60 Gy/8 fractions. Hepatic CT examinations were performed at 3- to 4-month intervals after SRT. RESULTS: We classified the appearance of high-dose-irradiated hepatic parenchyma on CT into three types: Type 1: eight lesions (53.3%) showed low attenuation areas on non-contrast CT and high attenuation areas on contrast CT; Type 2: five lesions (33.3%) showed low attenuation areas on non-contrast and contrast CT; Type 3: two lesions (13.3%) showed no change. The CT appearance of Type 1 after SRT was similar to that of pre-irradiated HCC, but the other types were easily differentiated from the primary tumors. These changes were observed and continued for 6 to 22 months after treatment. In two cases of Type 1, we performed histological examinations of the regions of high attenuation on contrast CT. These specimens revealed only radiation-induced hepatic injury. CONCLUSION: This study showed three types of CT appearance in high-dose-irradiated hepatic parenchyma. We suggest that other examinations be considered to distinguish between radiation hepatitis and local recurrences for HCC after SRT.     

肝胆管细胞癌并发肝脓肿的MSCT诊断

目的:探讨肝胆管细胞癌并发肝脓肿患者的MSCT诊断价值。方法:收集15例肝胆管细胞癌合并肝脓肿患者的MSCT资料进行回顾性分析。结果:15例患者CT平扫图像上发现31处边界模糊的低密度病灶,包括15处肝内胆管细胞癌和16处肝脓肿。病灶位于肝右叶者12处,位于肝左叶者19处,其中10例患者肝胆管细胞癌和肝脓肿位于同一肝段或肝叶,5例患者肝胆管细胞癌和肝脓肿位于不同肝段或肝叶。15处肝胆管细胞癌中,肿块型5处,表现为肝实质内轻～中度环形强化结节,常不伴有周围胆管扩张;管周浸润型4例,表现为沿胆管纵轴生长的树枝状肿块,伴有周围胆管扩张;肿块并管周浸润型6例,表现为肝实质内轻～中度延迟强化结节,常伴周围胆管扩张。16处肝脓肿病灶动态强化CT图像上,表现为中央完全强化者3处;中央不完全强化者6处,其中表现为伴中央小范围不强化者2处,表现为花簇状、多间隔强化者4处;表现为中央不强化者7例,称为肝脓肿的典型表现,即周围环形强化而中央不强化。结论:肝内胆管细胞癌和肝脓肿有着不同的强化特征,因此动态增强CT对同时患有肝胆管细胞癌和肝脓肿的患者有重要价值。     

肾脏乏脂肪血管平滑肌脂肪瘤的临床病理及CT表现

目的：探讨肾脏乏脂肪血管平滑肌脂肪瘤（AML）的临床、病理及CT 表现特征。方法：回顾性分析36例经手术病理证实的乏脂肪AML 的临床、病理及 CT 资料,将其分为上皮样血管平滑肌脂肪瘤（EAML）组和其他乏脂肪A ML组,观察病灶的数目、大小、形状、密度及其均匀性、劈裂征、血管影、假包膜、病灶的强化程度及强化方式等,采用SPSS 19．0软件进行统计学分析。结果：EAML组18例19灶,平均年龄40岁,其他乏脂肪AML 组18例22灶,平均年龄49岁。两组病灶最大径分别为（58．63±56．59）mm和（16．97±8．59）mm,P＜0．05;密度不均匀者分别为10例和4例, P＜0．05;形态不规则者分别为12例和10例,劈裂征阳性者分别为8例和13例,血管影分别为6例和2例,假包膜分别为6例和2例;病灶强化方式快进快出者分别为4例和10例,持续性强化者分别为14例和12例,渐进性强化者分别1例和0例,两组间病灶形状、劈裂征、血管影、假包膜均无统计学差异。EAML组病灶平扫、皮髓质期和肾实质期CT值分别为（44．3±10．7）HU、（101．6±26．6）HU 和（86．9±17．9）HU,其他乏脂肪AML 组各期CT 值分别为（37．1±7．3）HU、（108．7±23．8）HU和（87．6±13．6）HU。EAML组比其他乏脂肪AML组平扫CT值高,P＜0．05,增强后CT 值无统计学差异。结论：乏脂肪AML CT表现有一定特征性,EAML较其他乏脂肪AML发病年龄小,病灶体积大,平扫密度相对高且不均匀,明确诊断依赖于病理。     

Follow-up CT of moderately complex cystic lesions of the kidney (Bosniak category IIF)

OBJECTIVE: The purpose of this study is to show the use of follow-up CT studies in the management of moderately complex cystic lesions of the kidney (Bosniak category IIF). MATERIALS AND METHODS: The CT scans of 42 moderately complex cystic renal masses (Bosniak category IIF) with follow-up examinations for 2 years or greater or with pathology correlation (n = 3) were retrospectively analyzed by the authors in consensus. The complexity of each lesion was assessed on the basis of the number and appearance of the septa, wall thickness, interface with the kidney parenchyma, presence and amount of calcification, and contrast enhancement characteristics. Lesion size was measured in two dimensions. Follow-up examinations were evaluated for any interval change. RESULTS: The average size of the lesions was 3.9 x 3.6 cm, and the average follow-up time was 5.8 years (range, 2 years-18 years 4 months; median, 5.0 years). Eighteen lesions had fewer than five septa, 16 lesions had between five and nine septa, and eight lesions had more than nine septa. In 39 lesions, the wall or septa or both were slightly thickened, and in a single lesion, the wall and septa were hairline thin. The two remaining lesions were of uniformly high attenuation and completely intrarenal. Forty-one lesions had a sharp interface with the kidney, whereas one had an indistinct interface. Twenty lesions contained calcium. Enhancement was not shown in any lesions except for minimal enhancement of smooth walls or septa of some lesions. Follow-up examinations showed that three lesions had developed more calcification, one lesion had increased in overall size but appeared less complex, and three lesions had decreased in size. In addition, two lesions had become more complex and developed thicker septa, and these lesions proved to be cystic neoplasms. CONCLUSION: Follow-up CT studies are an effective way of managing patients with moderately complex cystic lesions of the kidney (Bosniak category IIF) because the absence of change supports benignity and progression indicates neoplasm.     

小儿肝脏未分化性胚胎性肉瘤的CT观察

目的 分析总结小儿肝脏未分化性胚胎性肉瘤的CT表现特点,以提高对本病的认识,从而能够早期诊断、积极治疗。方法 回顾性分析6例未分化性胚胎性肉瘤（UES）的临床、病理及影像特征,并结合文献加以讨论。6例患儿行腹部平扫,5例并行增强扫描。结果 平扫显示病灶边界清楚,3例病变为单囊,3例为多房囊腔,内有厚薄不均的分隔。囊性区内可见少许不规则软组织密度影,位于囊腔边缘或分隔周围。1例于病灶边缘见针尖钙化。增强后,可见肿瘤有一致密的,即病理上的纤维假包膜。实性部分轻度强化,囊性区不强化。4例超声图像表现为混合回声的实性包块内可见大小不等的无回声区。6例均经病理证实。结论 CT多表现为单囊或多囊性病灶,边界清楚,内有不同程度的实性部分,可见强化边。而超声图像则多表现为实性为主,其不一致性亦为本病的重要特点。     

CT features of renal infarction

PURPOSE: To demonstrate the different patterns of renal infarction to avoid pitfalls. To present 'flip-flop enhancement' pattern in renal infarction. MATERIALS AND METHODS: Retrospective review of a total of 41 renal infarction in 37 patients were done. These patients underwent initial CT and the diagnosis of renal infarction was confirmed with either follow up CT or at surgery. RESULTS: Twenty-three patients had wedge-shaped focal infarcts, nine patients had global and five patients had multifocal infarcts of the kidneys. Cortical rim sign was seen predominantly with global infarcts. In five patients, a 'flip-flop enhancement' pattern was observed. In two patients, planned renal biopsies due to tumefactive renal lesions were cancelled because of 'flip-flop enhancement' pattern on follow up CTs. CONCLUSION: Although most of our cases were straightforward for the diagnosis of renal infarction, cases with tumefactive lesions and global infarctions without the well-known cortical rim sign were particularly challenging. We describe a new sign, flip-flop enhancement pattern, which we believe solidified the diagnosis of renal infarction in five of our cases. The authors recommend further investigations for association of flip-flop enhancement and renal infarction.     

CT and MR imaging characteristics of infantile hepatic hemangioendothelioma

Aim

This study aims to analyze computed tomography (CT) and magnetic resonance (MR) imaging features of infantile hepatic hemangioendotheliomas before and after treatment.

Materials and methods

CT and MR examinations of seven infants with biopsy proven hepatic hemangioendotheliomas were retrospectively analyzed. The distribution, number, size, imaging appearance, enhancement pattern and post-treatment changes of the tumors were evaluated.

Results

A total of 153 hepatic hemangioendotheliomas were detected on CT (111) and MR (42) imaging. In six infants, 109/111 (98.2%) tumors were hypodense and 2/111 (1.8%) lesions contained calcification on unenhanced CT. On MR imaging, all 42 lesions in one infant were heterogeneously T1-hypointense and T2-hyperintense compared to the normal liver parenchyma. Contrast-enhanced CT and MRI showed peripheral rim (51.6%), uniform (48.4%), fibrillary (33.3%), and nodular (28.8%) contrast enhancement in the hepatic arterial phase. Homogeneous (100%), rim (98.2%) and mixed enhancement patterns were noted in tumors <1.0 cm, >2.0 cm and 1.0-2.0 cm in diameter respectively in the hepatic arterial phase. In three patients who underwent steroid therapy, follow-up CT examination demonstrated tumor size reduction and increased intra-tumoral calcification in two patients.

Conclusion

Infantile hepatic hemangioendotheliomas show some typical imaging features and size-dependent pattern of contrast enhancement on CT and MR imaging, which allow accurate imaging diagnosis and post-treatment evaluation.     

对转移性肝癌CT表现的分析(附23例报告)

目的:分析CT扫描对转移性肝癌的诊断价值。材料与方法:23例转移性肝癌经手术和/或病理证实,其原发灶有肺癌7例,胃癌6例,乳腺癌4例,胰腺癌2例,结肠癌2例,食管癌1例,以及子宫内膜癌1例。全部病例均经CT平扫和增强扫描。11例还于增强后1、3、5分钟做了延迟扫描。结果:CT平扫准确证实了多数病例(19/23)为多发性病灶且大多病灶(13/19)能被清楚辩认。增强扫描后可见如下CT表现:1.病灶整体轻度强化,2.病灶边缘轻度强化,3.病灶不强化,4.病灶缩小乃至消失,5.出现平扫时未检出的病灶。延迟扫描后,未见比增强扫描时更有意义的CT表现。结论:CT平扫和增强扫描对转移性肝癌的诊断具有重要实用价值。     

甲状腺未分化癌的 CT 特点

目的：总结甲状腺未分化癌的 CT 特点。方法回顾性分析12例经手术或活检病理证实的甲状腺未分化癌的 CT 表现。结果单发病灶11例(91.7%),表现为低密度肿物伴条带状、絮状或斑片状高密度区。11例(91.7%)为轻~中度强化。8例(66.7%)可见粗大钙化灶,其中4例为不完整环状或蛋壳状钙化。11例(91.7%)侵犯周围结构：气管6例(50%),食管4例(33.3%),带状肌7例(58.3%),喉2例(16.7%),血管6例(50%)。5例(41.7%)出现颈内静脉瘤栓。10例(83.3%)病理证实淋巴结转移,强化形式为3种类型：较均匀轻度强化4例(40%)、轻度强化伴内部小片状低密度区7例(70%)、轻度环形强化伴内部无强化低密度区7例(70%)。结论甲状腺未分化癌的 CT 特点包括低密度肿物,内部或边缘絮状或斑片状高密度区,粗大钙化灶,轻度强化。常见侵犯周围结构及淋巴结坏死。     

Patterns of contrast enhancement of tuberculous lymph nodes demonstrated by computed tomography.

The purpose of this study was to evaluate the contrast-enhanced CT characteristics of pathologic thoraco-abdominal lymph nodes in 38 patients infected with Mycobacterium tuberculosis (30 without AIDS and eight with AIDS). Unenhanced scans of chest, abdomen and pelvis were also done in all cases. The CT attenuation values and the enhancement characteristics of the largest node or group of lymph nodes were evaluated in a dynamic sequence over a period of 10 min. On unenhanced CT the nodes were of low attenuation (less than 30 HU) in 18 cases and of soft tissue attenuation (greater than 35 HU) in 20 cases. Four post-contrast patterns of enhancement were found: (i) peripheral rim enhancement (n = 22); (ii) inhomogeneous enhancement (n = 8); (iii) homogeneous enhancement (n = 6); and (iv) homogeneous nonenhancing nodes (n = 2). Increase of attenuation and obliteration of perinodal fat was found in 13 cases, most of them with the peripheral rim enhancement pattern. Seven cases had a combination of enhancing patterns in the same nodal group. The central enhancement was usually moderate (mean, 30 HU) but was marked (greater than 60 HU) in three patients with the homogeneous enhancement pattern. Neither the nodal attenuation values nor the patterns of enhancement are characteristic of tuberculosis, however adenopathy showing peripheral rim-enhancement with relative low attenuation centres can suggest a diagnosis of tuberculosis in the appropriate clinical setting.