The frequency,appearance, and significance of splenic perfusion defects on CT arterial portography

Background: The purpose of this study was to determine the frequency, appearance, and significance of splenic perfusion defects on computed tomographic arterial portography (CTAP). Methods: CTAP was performed with dynamic scanning at 1-cm increments on 46 consecutive patients prior to laparotomy. Two readers retrospectively reviewed these studies in consensus and recorded the number, size, and shape of focal splenic perfusion defects. These defects were later correlated with surgical findings and at least one of the following imaging modalities: delayed CT 4<+>–<+>6 h after CTAP, intravenously enhanced CT, sonography, or magnetic resonance imaging (MRI). Results: Splenic perfusion defects were present in 14 of 46 CTAP studies (30%), and in seven patients these defects were multiple. Most defects were wedge-shaped and peripherally located, although several round defects simulating metastases were also present. The spleen was normal at surgery in all patients, and comparison imaging revealed only a small splenic infarct in one patient on MRI. Conclusions: Splenic perfusion defects occur in about one-third of patients referred for CTAP, are usually wedge-shaped but may be round, and should not be interpreted as metastases without other evidence of a space-occupying mass. Received: 11 October 1994/Accepted: 6 November 1994     

Hepatocellular carcinoma with sarcomatous change: characteristic findings of two-phased incremental CT

Background: Because of its poor prognosis, the diagnosis of hepatocellular carcinoma with sarcomatous change (HCCSC) is clinically important. The purpose of this study is to elucidate the characteristic CT findings of HCCSC. Methods: Two-phased dynamic incremental CT images of six histologically proven HCCSC were retrospectively reviewed. Results: All tumors (100%) exhibited peripheral enhancement on delayed CT images. Lymphadenopathy was observed in 100% (six of six patients); intrahepatic metastases, in 83% (five of six). Both metastatic lesions showed findings similar to those of the primary hepatic tumors, such as peripheral enhancement. Histopathologically, delayed and/or prolonged peripherally enhanced areas consisted of viable cancer cells with sarcomatous changes. Conclusions: The appearance of HCCSC on CT is that of an irregularly demarcated intrahepatic mass with delayed or prolonged peripheral enhancement, frequently with intrahepatic metastases and lymphadenopathy. Received: 5 December 1994/Accepted: 4 January 1995     

Focal hepatic nodules after transcatheter oily chemoembolization; detection with spiral CT versus conventional CT

Background: The objective of this study was to determine if spiral computed tomography (CT) results in increased rate of detection of focal hepatic nodules containing iodized oil after transcatheter oily chemoembolization when compared with conventional CT. Methods: Spiral CT with single 24-s breath-hold technique was compared with conventional sequential CT in 42 patients with suspected hepatocellular carcinomas. Two sets of CT scans obtained after transcatheter oily chemoembolization were independently reviewed by two radiologists. The slice thickness was 10 mm for both data sets. The number and sizes of focal hepatic nodules containing iodized oil were documented. All 42 patients had at least one hepatic nodule. The lesion size varied from 2 mm to 12 cm. Results: In six of the 42 patients, more hepatic nodules could be identified on spiral CT compared with conventional CT. When scans with spiral CT were used, 107 nodules were detected, whereas 98 nodules were detected with conventional CT. Overall, nine (9%) more nodules were detected with spiral CT (<+>p= .002). If lesions larger than 2 cm are excluded, nine (15%) more lesions were detected with spiral CT (<+>p= .002). Conclusion: Spiral CT results in increased rate of detection of focal hepatic nodules after transcatheter oily chemoembolization, particularly in lesions smaller than 2 cm. Received: 11 October 1994/Accepted: 6 November 1994     

Imaging diagnosis of hepatic metastases of pancreatic carcinomas: significance of transient wedge-shaped contrast enhancement mimicking arterioportal shunt

We aimed to evaluate the imaging findings of hepatic metastases from pancreatic cancers, especially wedge-shaped enhancement and its etiology. Dynamic CT and MR images were performed in 87 patients with liver metastases from pancreatic carcinomas, and CT during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) in 51 patients. Liver metastases were multiple in 84 patients (97%) and solitary in only three (3%). In 44 of 87 patients (51%), all liver metastases showed ring-like enhancement compatible with metastatic adenocarcinomas on dynamic CT and/or dynamic MR imaging. In 37 patients, more than one metastatic lesion showed wedge-shaped contrast enhancement on dynamic CT, dynamic MRI and CTHA, and wedge-shaped perfusion defect on CTAP adjacent to metastatic tumors. Six patients showed multiple wedge-shaped enhancements, which were initially diagnosed as multiple arterioportal shunts (AP shunts). However, metastatic tumors appeared within the area of wedge-shaped enhancement and increased in size on follow-up CT and/or MR images. After all, 43 of 87 patients (49%) had AP shunt like contrast enhancement adjacent to liver metastases. Liver metastases from pancreatic carcinomas frequently show transient wedge-shaped enhancement, and should not be misdiagnosed as nontumorous arterioportal shunts.     

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.     

Restorative proctocolectomy: morphological and functional study with coronal CT

Background: Restorative proctocolectomy with ileal pouch has become the surgical treatment of choice for patients with ulcerative colitis (UC) and familial polyposis of the colon. Defecography is the radiological technique commonly employed to obtain detailed information on function and morphology of the ileal pouch; it allows the direct visualization of the ileal pouch and the anal canal, but it does not provide the visualization of the pelvis. Methods: In all patients, computed tomography (CT) on coronal planes was performed to determine its possibilities as an alternative to defecography; 10 patients with UC submitted to restorative proctocolectomy and were examined. Results: Coronal CT images provided a panoramic vision of the pelvis and demonstrated the morphology of the ileal pouch, the thickness of its walls, and its correlation with the surrounding tissues. Coronal CT also allowed the evaluation of the continence of ileo-anal and ileo-ileal anastomosis and the functional changes of the perineal muscles at rest and during squeezing. Conclusion: CT images acquired on coronal planes allows an easy and clear detection of the major postoperative complications, such as stenosis or dehiscences of the anastomosis, pelvic phlogosis, and fistulae. Received: 29 December 1994/Accepted: 5 February 1995     

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     

Wedge-shaped intrahepatic cholangiocarcinoma:MRI<+>–<+>pathologic correlation

On magnetic resonance imaging (MRI) studies, wedge-shaped areas of signal abnormality noted in association with liver lesions have been attributed to secondary phenomena and are said to be substantially larger than the actual tumor. We describe the MRI and pathological appearance of a wedge-shaped cholangiocarcinoma. In cases where therapy might be affected, biopsy of wedge-shaped MRI abnormalities associated with hepatic malignancy should be considered for accurate tumor staging. Received: 23 December 1994/Accepted: 25 January 1995     

Computed tomography during arterial portography under temporary balloon occlusion of the hepatic artery: evaluation of pseudolesions caused by arterio-portal venous shunts

Background: Computed tomography during arterial portography (CTAP) under temporary balloon occlusion of the hepatic artery (BOHA-CTAP) was introduced to evaluate pseudolesions caused by portal venous impairments such as arterioportal shunt and tumor thrombus. Methods: BOHA-CTAP was performed in seven patients with hepatocellular carcinoma and correlated with clinical outcomes. For patients with wedge-shaped defects suggestive of pseudolesions, BOHA-CTAP was obtained by a 5-F balloon occlusion catheter into the proper hepatic artery through the second 5-F introducer inserted into the common femoral artery a few centimeters below the first 5-F sheath for CTAP. Results: Eight pseudolesions were determined clinically on follow-up CT, ultrasonography, or magnetic resonance imagings. On BOHA-CTAP, five of the eight pseudolesions were eliminated, and two were diminished in comparision with conventional CTAP. One wedge-shaped defect due to tumor thrombus in the portal vein did not show any change. Conclusion: BOHA-CTAP can reduce pseudolesions caused by portal venous impairments and enable the demarcation of the true tumors. RID=" ID=" <E5>Correspondence to:</E5> J. Koizumi Received: 3 August 1999/Revision accepted: 8 March 2000     

Spread of gallbladder carcinoma: CT evaluation with pathologic correlation

Background: To assess the accuracy of computed tomographic (CT) imaging in the detection of spread and staging of gallbladder carcinoma. Methods: CT findings of spread of gallbladder carcinoma in 59 Japanese patients who underwent radical surgery were correlated retrospectively with pathologic findings. Results: The incidence of histologically proven nodal involvement was 54% (32 patients) and the most common spread of gallbladder carcinoma. The sensitivities in CT detection of N1 and N2 nodal involvement were 36% and 47%, respectively; positive predictive values were 94% and 92%, respectively. Direct extension to the liver, extrahepatic bile duct, and gastrointestinal tract or pancreas were histologically confirmed in 24, 18, and five patients. The sensitivities in the CT detection of direct spread to the liver of less than 2 cm, more than 2 cm, the extrahepatic bile duct, and the gastrointestinal tract or pancreas were 65%, 100%, 50%, and 57%, respectively; positive predictive values were 77%, 100%, 90%, and 100%, respectively. The incidence of liver metastases and involvement of interaortocaval nodes were 7% and 16%, respectively. The sensitivities in CT detection of liver metastases and involvement of interaortocaval nodes were 75% and 21%, respectively; positive predictive values were 100% and 86%, respectively. CT could not detect direct spread to omentum and peritoneal seedings. Conclusion: For detecting the spread of gallbladder carcinoma, CT imaging has low to moderate sensitivity; however, CT imaging can help in determining resectability and in planning the treatment, especially in advanced-stage gallbladder carcinoma, because of a high positive predictive value. Received: 5 July 1995/Accepted: 8 August 1995     

Large lipomas of the colon: CT and MR findings in three symptomatic cases

We report on three patients with large lipomas in the wall of the cecum, causing intussusception. Endoscopy is the preferred modality for small lipomas, whereas CT and MR imaging are more useful in their ability in detecting fatty masses and assessing the location of lesions. Barium enema study may contribute to the preoperative planning in selected cases. Received: 1 November 1994/Accepted after revision: 5 January 1995     

Dynamic MR imaging of hepatolithiasis

Background: To report the dynamic magnetic resonance (MR) imaging findings of hepatolithiasis. Methods: Dynamic MR images (fast spoiled gradient echo sequence with intravenous injection of gadopentate dimeglumine) and computed tomography, cholangiography, or angiography of nine patients with hepatolithiasis are analyzed. Results: All affected hepatic segments showed atrophic changes and contained dilated intrahepatic ducts. These segments showed either iso- or hypointensity on T1-weighted imaging and hyperintensity on T2-weighted imaging. Preferential enhancement was noted throughout all phases of the dynamic study and persisted to delayed T1-weighted imaging in seven patients. In the last two patients, severe atrophic changes made evaluating signal intensity differences and enhancement patterns difficult. Conclusion: In addition to intrahepatic stones and biliary dilatation, segmental atrophy, signal intensity differences, and preferential and persistent enhancement are important MR findings of hepatolithiasis. Received: 18 June 1997/Accepted: 23 July 1997     

Significance of the computed tomography finding of subcapsular hepatic necrosis in liver transplantation

Background: To evaluate the clinical significance of the computed tomographic finding of subcapsular hepatic necrosis following liver transplantation. Methods: 105 computed tomography scans performed in 50 allografts, 6 days to 4 years following transplantation, were retrospectively reviewed and divided into two groups: those with and those without the computed tomographic finding of subcapsular hepatic necrosis. Extrahepatic fluid, biliary dilatation, circumcaval rings, periportal collar, biochemistry, and random biopsies were correlated with the computed tomographic finding of subcapsular hepatic necrosis. Results: Computed tomographic finding of subcapsular hepatic necrosis was demonstrated at some point in 21 (42%) patients and was never demonstrated in 29 (58%) patients. The association of periportal collar with the computed tomographic finding of subcapsular hepatic necrosis was significant; there was no significant association with other computed tomographic findings. There was no significant difference in serum transaminases between the two groups. There was no significant difference in necrosis on biopsy between the two groups; however, the association of acute cellular rejection with the computed tomographic finding of subcapsular hepatic necrosis was significant. Conclusions: Computed tomographic finding of subcapsular hepatic necrosis is a common finding following liver transplantation, which has little clinical prognostic significance. Received: 13 December 1994/Accepted: 5 January 1995     

Dysplastic nodules of the liver: imaging findings

Background: To verify characteristic features of hepatic dysplastic nodules at different imaging modalities. Methods: Twenty-eight patients with 37 dysplastic nodules of the liver (0.8–3.0 cm) underwent sonography (28 patients), computed tomography (CT; 24 patients), magnetic resonance (MR; 11 patients), and angiography (12 patients). Each nodule was analyzed for echogenicity, attenuation, signal intensity, and vascularity. Results: Echogenicity of nodules was high in 16 (43%), homogeneous in two (6%), and low in 19 (51%) of 37 nodules. Attenuation of nodules was high in one (7%), homogeneous in four (26%), and low in 10 (67%) of 15 nodules on the arterial-phase CT images; homogeneous in five (33%) and low in 10 (67%) of 15 nodules on the portal-phase CT images; and high in four (17%), homogeneous in six (26%), and low in 13 (57%) of 23 nodules on the delayed-phase CT images. Signal intensity of nodules was high in 15 (94%) and homogeneous in one (6%) of 16 nodules on T1-weighted MR images and was homogeneous in seven (44%) and low in nine (56%) of 16 nodules on T2-weighted MR images. Vascularity of nodules was avascular in 14 (88%) and slightly vascular in two (12%) of 16 nodules. Conclusions: Hepatic dysplastic nodules show diverse imaging characteristics with different imaging techniques; however, common imaging findings of hepatic dysplastic nodules are low echo, low attenuation, and high, low, or homogeneous intensity on T1- and T2-weighted MR, and avascularity. Received: 13 May 1998/Accepted: 1 July 1998     

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     

Spontaneous rectus sheath hematomas: clinical and radiological features

We reviewed the clinical and radiological features in eight patients with spontaneous rectus sheath hematoma (RSH). The diagnosis was confirmed at surgery in four patients, and spontaneous resolution occurred in the other four. All patients were elderly adults. Acute abdominal pain and a palpable mass after muscular strain, such as coughing or twisting, were features highly suggestive of RSH. Sonographically, these hematomas may be confused with abdominal wall tumors. On CT scans, a hyperdense mass posterior to the rectus abdominis muscle with ipsilateral anterolateral muscular enlargement is considered characteristic of acute RSH, although chronic RSH may be isodense or hypodense relative to the surrounding muscle. MRI is very useful in the diagnosis of RSH, which is demonstrated as a high signal intensity area on both T1- and T2-weighted images, especially when the CT findings are not specific for RSH. Received: 16 August 1994/Accepted: 3 October 1994     

Peritumoral spared area in fatty liver: correlation between opposed-phase gradient-echo MR imaging and CT arteriography

BACKGROUND: The purpose of the present study was to evaluate the magnetic resonance findings of a spared area of fatty liver caused by hepatic tumors and clarify the etiology of this phenomenon by computed tomographic (CT) arteriography. METHODS: Six patients with hepatic tumors (metastases from colon cancer, n = 3; breast cancer, n = 2; hepatocellular carcinoma, n = 1) were examined. In-phase (IP) and opposed-phase (OP) T1-weighted spoiled gradient-echo images were obtained. CT during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) were also performed. Pathologic confirmation was obtained in three patients with metastases from colon cancer. RESULTS: In all six patients, peritumoral ringlike or wedge-shaped hyperintense areas in relation to the tumor and the surrounding steatotic liver parenchyma were clearly visualized on OP images alone. This area appeared as a perfusion defect on CTAP and ringlike or wedge-shaped enhancement on CTHA. Pathologically, the peritumoral hyperintense areas on OP images were compatible with the spared area of fatty liver. CONCLUSION: A peritumoral spared area can be demonstrated with OP images. The etiology of the phenomenon is correlated with decreased portal flow and increased arterial flow in the peritumoral hepatic parenchyma.     

Enhancing ascites: an aid to CT diagnosis

Enhancement of ascitic fluid on delayed contrast-enhanced CT has been described as a potential pitfall in diagnosis. We present a case in which the phenomenon was beneficial to diagnosis. Enhancement of ascites was useful in delineating the entire extent of a cystic pelvic mass. We also discuss probable molecular and histologic mechanisms responsible for this unique type of enhancement. Received: 8 August 1994/Accepted after revision: 17 November 1994     

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     

肝脓肿周围一过性节段强化动态CT表现及其临床意义

本文对肝脓肿周围一过性节段强化动态CT表现及其在抗炎治疗随访中的临床意义作一初步探讨 ,并结合文献探讨其病理基础。1　材料与方法从 2 0 0 1年 5月至 2 0 0 2年 3月间共收集到 5例肝脓肿 ,其中男 4 ,女 1例 ,年龄范围 33～ 5 2岁 (平均 4 3.5岁 )。 5例患者有发热、腹痛及白细胞计数增高 ,1例患者有小肠坏死切除术病史。 5例患者中 1例采用SiemensCR常规CT行改良动态增强(患者以 3ml/s速率团注对比剂 10 0ml,于开始注药后 2 5s嘱患者屏气 ,依平扫确定病灶的部位以 10mm层厚 ,10mm间隔扫 3个层面 (2s一层 ,间隔 2s) ,然后嘱患者呼吸 1…