Abdominal CT following liver transplantation

Computed tomography (CT) is one of several imaging modalities employed in the evaluation of complications following orthotopic liver transplantation. Abdominal CT scans were performed in 92 (48%) of the first 190 liver transplant patients at our institution. These studies were retrospectively reviewed to determine the indications for CT in this population and to determine the incidences of the various CT findings. The major indication (70%) was detection of bile leakage, hemorrhage, or abscess. The role of CT was primarily to discover such abnormal fluid collections and guide their percutaneous drainage. This article describes a wide spectrum of common and uncommon findings following liver transplantation and illustrates their CT features.     

Undifferentiated embryonal sarcoma of the liver treated with chemotherapy: CT imaging in four patients

Background: The purpose of this study was to describe the computed tomography (CT) findings of undifferentiated embryonal sarcoma after chemotherapy and to correlate the CT imaging findings with pathologic findings. Methods: Ten CT images obtained before and after chemotherapy in four patients with hepatic undifferentiated embryonal sarcoma were retrospectively reviewed and correlated with pathologic findings. Results: After chemotherapy, tumor volume decreased by 50–90% and initially nonresectable tumor or gross residual tumor was successfully excised in three patients. In all patients, enhancing peripheral solid portions and septations changed to low-attenuation areas, and in three patients increased or de novo calcifications were found at the periphery of the tumor. Resected pathologic specimen after chemotherapy showed well-encapsulated masses with central necrosis, fibrosis, and dystrophic calcifications. Conclusions: These CT findings will be useful in monitoring the treatment response of hepatic undifferentiated embryonal sarcoma during chemotherapy.     

Parenchymal changes of the liver in cholangiocarcinoma: CT evaluation

We evaluated parenchymal changes of the liver in 92 patients (41 peripheral types and 51 hilar types) with cholangiocarcinomas studied by bolusenhanced computed tomography (CT). In 39% of patients with the peripheral type, a wedge-shaped increased enhancement of the liver was observed peripheral to the tumor on bolus-enhanced CT. Tumor was observed in all cases. In 58.8% of patients with the hilar type, a segmental or lobar increased degree of enhancement of the liver was observed, but the tumor was demonstrated in only 58.8%. Atrophy was accompanied by areas of increased enhancement in 80% of hilar type and 25% of peripheral type. Areas of increased degree of enhancement corresponded to a wedged-shaped perfusion defect on CT during arterial portography. On magnetic resonance imaging (MRI), those lesions showed hyperintensity on T2-weighted images. Most of these changes were considered to be due to reversible hepatic parenchymal ischemia secondary to portal vein invasion by the tumor.     

Diaphragmatic endometriosis: CT and MR findings

A case of endometrioma presenting as a diaphragmatic mass in a 36-year-old woman is described. The computed tomographic (CT) and magnetic resonance (MR) findings of the lesion at this rare site of involvement are illustrated, and the pertinent literature is briefly reviewed.     

Calcifications of portal venous system wall: CT findings in three patients

Three cases of portal venous system wall calcifications demonstrated by computed tomography are presented. The clinical features, possible pathogenesis, differential diagnosis, and therapeutic significance of this condition are reviewed.     

Pseudomyxoma peritonei with progressive calcifications: CT findings

Development of abdominal calcifications due to pseudomyxoma peritonei is rare. The authors present three cases whereby computed tomographic (CT) studies during or after chemotherapy for pseudomyxoma peritonei demonstrated development and progression of punctate calcifications in the abdomen. The clinical and CT findings of these cases are presented together with a brief review of the pertinent literature.     

Progressive CT appearance of hepatic metastases from colorectal carcinoma

An 8-year retrospective review of 106 serial computed tomographic (CT) examinations performed on 32 patients with colorectal carcinoma metastatic to the liver was done to determine if the CT appearance of such metastases changed with a favorable response to chemotherapy or with progression of disease. Of these 32 patients, 15 underwent placement of an infusion pump for delivery of chemotherapy directly into the hepatic artery, 3 underwent partial hepatectomy, 1 underwent both procedures, and 13 underwent neither. Regression of hepatic metastases (7 patients), only seen following infusion pump placement, was associated with a decrease in size and an increase in margination of lesions. In two of these patients regression of metastases was seen in one area of the liver with subsequent progression or development of metastases in another region, presumably due to preferential delivery of chemotherapeutic agent. Progression of disease (23 patients) was associated with an increase in both size and number of lesions that became progressively less well marginated. Development of poorly marginated or infiltrative characteristics at the periphery of the lesion was associated with a poor prognosis. Thus, the CT characteristics of hepatic metastases from colorectal carcinoma differ with a favorable response to chemotherapy and with progression of disease.     

CT appearance of the Roux limb following choledochojejunostomy in liver transplantation

Choledochojejunostomy in Roux-en-Y is a frequent form of biliary reconstruction in liver transplants. On computed tomography (CT), fluid in the Roux limb may simulate a fluid collection. We studied the CT appearance of the Roux jejunal limb in 25 normal and complicated liver transplant patients. The Roux limb was identified in 21 (84%) of 25 cases. Most frequently useful features were characteristic location, continuous tubular appearance, biliary stent, bull's eye appearance, and gas in the loop. Two of 18 normal Roux loops were initially suspected of being abscesses and one gas-containing abscess was initially mistaken for the Roux limb. In five of seven patients with complications (four abscesses, two bile leaks, one anastomotic hemorrhage), identification of the Roux limb was possible and was useful in interpreting CT scans. Knowledge of the appearance of the normal and abnormal Roux limb is essential for proper interpretation of CT scans in liver transplant patients.     

Fatal liver necrosis following percutaneous ethanol injection for hepatocellular carcinoma

A 76-year-old man underwent an injection of 5 ml of ethanol for the treatment of a hepatocellular carcinoma 3 cm in diameter. Shortly after the procedure, he had an attack of abdominal pain. His condition soon deteriorated and he died 5 days later. Massive hepatic necroses distant from the injection site and a myocardial infarction were found at autopsy. To our knowledge, this is the first fatality associated with percutaneous ethanol injection therapy.     

Dynamic CT of hepatic masses using intraarterial enhancement: Advantages and pitfalls

Forty-two patients were evaluated by dynamic incremental computed tomography (CT) following transcatheter infusion of contrast material into the celiac and hepatic arteries. Most of these patients had liver metastases from colorectal carcinoma, but the series also included two cases of hepatic hemangiomas, one case of granulomas due to atypical mycobacterium, and two cases of retroperitoneal tumors involving the liver. Several distinct patterns of liver opacification were recognized, reflecting differential perfusion of hepatic lobes during selective intraarterial contrast enhancement. The spectrum of observed findings, as well as the advantage or limitations of this technique, are described.     

CT findings in left paraduodenal herniae

Computed tomography (CT) was used to evaluate mass effect on the greater curvature of the stomach in two children with histories of intermittent, recurrent vomiting. The paraduodenal herniae were identified on CT in both of these patients as small bowel interposed between the stomach and the body of the pancreas.     

Comparison of iohexol-240 versus iohexol-300 in abdominal CT

Forty patients without evidence of liver, kidney, or significant cardiac disease were prospectively divided into two groups of 20, receiving either iohexol-240 or iohexol-300. A contrast load of 150 ml was administered in conjunction with a rapid scanning technique at a preselected, fixed level to include liver, renal cortex, and aorta. Peak enhancement was calculated as change in Hounsfield units (HU) over baseline for each area of interest. Mean peak enhancement and standard deviation were calculated for each organ, and the difference between the means for the two contrast agents was compared using the Student'st test.Differences were not statistically significant with allp values greater than 0.05. Our results suggest iohexol-240 is preferred to iohexol-300 for body computed tomography (CT) due to its lower cost and iodine load without statistically significant change in diagnostic quality of the examination.     

Pseudocyst following splenectomy: Impact of CT and ultrasound on its diagnosis and management

Three cases of pseudocysts occurring after splenectomy are presented. Sonography and computed tomography were helpful in diagnosing the pseudocysts as well as providing guidance for subsequent drainage. Demonstration of a cystic mass adjacent to the tail of the pancreas following splenectomy suggests the diagnosis of postsplenectomy pseudocyst and has important implications for clinical management.     

腹部增强CT扫描中准确把握肝脏动脉期时相的临床应用研究

目的探讨腹部增强CT动脉期最佳强化时间的扫描时机。方法选取400例行腹部增强CT扫描的受检者,分为A、B两组,每组各200例,均使用对比剂追踪技术,选择降主动脉肝门水平自动监测,Ct值达到100 HU,A组直接触发扫描,B组触发延时20 s开始扫描。两组受检者实质期扫描均于动脉期扫描结束后延时30 s扫描。分别测量两组动脉期和肝实质期门脉分支层面肝实质、腹主动脉和门静脉主干Ct值,并进行统计分析。结果两组受检者的图像质量均可满足诊断要求。A组,动脉期肝实质Ct值为64.08±6.55,门脉主干、腹主动脉明显强化,肝实质少量强化。B组,动脉期肝实质Ct值为88.93±8.99,肝动脉、腹主动脉的明显强化,肝实质强化明显。两组受检者的动脉期肝实质测量数据差异具有统计学意义(P0.05)。两组受检者动脉期、实质期的门静脉主干、腹主动脉的Ct值相比较差异无统计学意义(P0.05)。结论腹部增强CT扫描中,利用对比剂追踪技术,监测阈值达到100 HU后,延时20 s进行扫描,可获得满意的更利于影像诊断的实质脏器动脉期强化图像。     

Biliary cystadenoma: Ultrasound,CT, and MRI

Two cases of intrahepatic biliary cystadenoma, a rare tumor with malignant potential, are discussed. The sonographic, computed tomographic (CT), and magnetic resonance imaging (MRI) findings are presented together with clinical features of this entity and a brief review of the pertinent literature.     

Liver parenchymal changes after transcatheter arterial embolization therapy for hepatoma: CT evaluation

We retrospectively reviewed computed tomographic (CT) findings of 118 patients with hepatoma who received sequential follow-up CT after transcatheter arterial embolization (TAE). Thirty-five patients received TAE using Gelfoam particles with cisplatin, 37 patients using Gelfoam particles and iodized oil (Lipiodol) with cisplatin, and 46 patients using iodized oil with cisplatin. Liver atrophy was observed in 33 patients, lobarly or focally, depending on the embolized area. It was frequently associated with portal vein occlusion by the tumor, usage of iodized oil, and repeated embolization therapy. The lobar atrophy was seen in patients who had portal vein occlusion and/or received repeated embolization therapy. The focal atrophy was observed in patients who were administered iodized oil. Infarction developed in four patients who had a thrombus in the portal vein and received peripheral embolization therapy using iodized oil. We conclude that liver parenchymal changes occur frequently in patients who have portal vein occlusion and/or receive peripheral embolization using iodized oil.     

Calcified splenic metastasis from gastric carcinoma

Isolated splenic metastases are uncommon. We report CT and MRI features of an isolated, large, calcified splenic metastasis from a primary adenocarcinoma of the stomach. Presence of a calcified splenic mass with a known primary malignancy of mucinous nature should suggest the diagnosis of splenic metastasis even if it occurs in isolation.     

CT灌注成像预测宫颈鳞癌新辅助化疗后微小淋巴结转移

目的 探讨CT灌注成像预测宫颈鳞癌新辅助化疗后微小淋巴结转移的价值。方法 收集在我院接受新辅助化疗并手术的46例宫颈鳞癌患者,根据术后病理是否存在微小淋巴结转移（转移淋巴结短轴径<10 mm）及短期随访淋巴结转移的情况将其分为无微小淋巴结转移组（n=32）和存在微小淋巴结转移组（n=14）,比较其CT灌注参数并分析其诊断价值。结果 存在微小淋巴结转移组的肿瘤化疗前肿瘤最大直径、血流量（BF）、血容量（BV）均大于无微小淋巴结转移组（P均<0.05）;两组间化疗后肿瘤最大直径、渗透性、达峰时间（TTP）差异无统计学意义（P均>0.05）。多因素Logistic回归分析结果显示BF、化疗前肿瘤最大直径是新辅助化疗后微小淋巴结转移的独立影响因素。ROC曲线显示BF[AUC=0.86,P<0.001,95%CI（0.75,0.96）]较化疗前肿瘤最大直径[AUC=0.70,P<0.02,95%CI（0.54,0.88）]对宫颈鳞癌新辅助化疗后是否存在微小淋巴结转移具有更高的预测价值。结论 CT灌注成像对预测宫颈鳞癌新辅助化疗后微小淋巴结转移具有较高的应用价值。     

Periportal halo: A CT sign of liver disease

Periportal halos are defined as circumferential zones of decreased attenuation identified around the peripheral or subsegmental portal venous branches on contrast-enhanced computed tomography (CT). These halos probably represent fluid or dilated lymphatics in the loose areolar zone around the portal triad structures. While this CT finding is nonspecific, it is abnormal and should prompt close scrutiny of the liver in search of an underlying etiology. Periportal halos which may be due to blood are commonly seen in patients with liver trauma. Periportal edema may cause this sign in patients with congestive heart failure and secondary liver congesion, hepatitis, or enlarged lymph nodes and tumors in the porta hepatis which obstruct lymphatic drainage. This CT sign has also been observed in liver transplants (probably secondary to disruption and engorgement of lymphatic channels) and in recipients of bone marrow transplants who might develop liver edema from microvenous occlusive disease. While the precise pathophysiologic basis of periportal tracking has not been proven, it represents a potentially important CT sign of occult liver disease.     

Focal fatty liver lesions in alcoholic liver disease: A broadened spectrum of CT appearances

The CT examinations of 26 consecutive alcoholic patients with focal fatty infiltration of the liver were analyzed. Five different patterns of focal fatty infiltration were noted. In most alcoholic patients these appearances present no diagnostic problem and further confirmation can be obtained by repeating the CT scan within 1–2 weeks to see if interval resolution occurs following enforced abstinence. In select instances, more invasive and definitive procedures such as superselective angiography or liver biopsy may be necessary to differentiate these findings from other more serious diseases they may closely resemble, such as primary or secondary liver neoplasms.