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     

Iodized-oil retention within hepatic hemangioma: characteristics on iodized-oil CT

Objective: The purpose of this study was to describe the characteristic computed tomographic (CT) appearance of iodized-oil retention in hepatic hemangioma and to evaluate the duration of the retention of iodized oil on follow-up CT. Methods: Seventeen hepatic hemangiomas of 14 patients were studied with CT performed 1–3 weeks after injection of 2–9 ml of iodized oil (iodized-oil CT) for the characterization of focal hepatic lesions, which needed differential diagnosis with hepatocellular carcinoma in 10 patients, for therapy in two patients, and for chemoembolization therapy of accompanying hepatocellular carcinomas in two. Twelve patients had 1–7 follow-up CT scans within an interval of 1–38 months. Results: In all cases, iodized-oil CT showed iodized-oil retention within the tumor, regardless of tumor size, shape, location, and amount of injected iodized oil. The distribution was incomplete and predominantly peripheral in all cases. Central retention was also seen in seven cases, in which a relatively large amount of iodized oil was injected, but retention of iodized oil in the tumor was incomplete even in two cases in which a large amount of iodized oil was injected to relieve symptoms and in three cases in which prominent uptake of surrounding liver parenchyma was seen. Patterns of retention were predominantly spotty in five, predominantly nodular in four, and mixed in eight patients. Retention materials slowly washed out but persisted for at least 3 months and up to 38 months (mean = 18.1 months), and complete washout was not seen in any cases at follow-up CT. Conclusion: In all cases of hepatic hemangiomas, iodized oil was retained, and retention persisted over several months. Distribution and patterns of retention were characteristically peripheral, spotty, and nodular at iodized-oil CT. Knowledge of the iodized-oil CT appearance of hepatic hemangioma would be helpful to interpret follow-up CT studies of patients who have undergone iodized-oil chemoembolization procedures. Received: 22 August 1994/Accepted: 31 March 1995     

Correlation of perfusion abnormalities on CTAP and immediate postintravenous gadolinium-enhanced gradient echo MRI

Background: The purpose of this study was to evaluate patients with wedge-shaped perfusion defects seen on spiral CT arterial portography for the presence of transient increased wedge-shaped enhancement on dynamic gadolinium-enhanced gradient echo MR images. Methods: Nineteen patients underwent CTAP and MRI within a 2-week interval. All patients with wedge-shaped perfusion defects on CT arterial portography were evaluated in a separate review session for the presence of transient increased segmental hepatic enhancement on dynamic gadolinium-enhanced spoiled gradient echo (SGE) MR images. Results: Eight patients were identified to have subsegmental, segmental, or lobar wedge-shaped perfusion defects by CT arterial portography. In 8/8 patients, there was transient wedge-shaped increased hepatic enhancement on MR images which corresponded to the perfusion defects identified on CT arterial portography. Transient increased enhancement on MR images was observed on immediate postgadolinium images as high-signal intensity of the involved subsegment, segment, or lobe. This relatively high-signal area faded to near isointensity in all cases on images obtained at 45 s. Conclusion: Wedge-shaped perfusion defects demonstrated by CT arterial portography corresponded to wedge-shaped increased hepatic enhancement following gadolinium administration on SGE MR images. Received: 29 December 1994/Accepted: 7 February 1995     

Small hepatic nodules in cirrhosis: ultrasonographic, CT, and MR imaging findings

Purpose: The purpose of this study was to assess the imaging findings of pathologically-proved small hepatic nodules 2 cm in size or smaller detected with ultrasonography in cirrhotic patients with suspected hepatocellular carcinoma (HCC). Materials and Methods: We evaluated sonographically detected 32 small hepatic nodules which were pathologically confirmed in 23 consecutive cirrhotic patients who were suspected of having HCC. Twenty-six lesions were confirmed with ultrasonographically-guided aspiration needle-core biopsy, and six with definitive surgery. Ultrasonographic examination records were retrospectively reviewed. CT, and MR images obtained with various imaging techniques were retrospectively reviewed by two radiologists in a blind fashion. Results: The 32 hepatic nodules were comprised of seven focal fatty changes, two large regenerative nodules, three low-grade dysplastic nodules, five high-grade dysplastic nodules, and fifteen HCCs. Ultrasonography showed various echogenicity for the hepatic nodules. The signal-intensity characteristics with T1-weighted spin-echo, in-phase gradient-recalled-echo, and dynamic MR imagings may be useful in distinguishing HCC from nonHCC nodules. Conclusions: Nearly half of small hepatic nodules detected with ultrasonography were nonHCC nodules. Ultrasonographic findings may not be reliable in characterizing small hepatic nodules in cirrhosis. CT and MR imaging obtained with the various techniques are still insensitive to these hepatic nodules. RID="ID="<e5>Correspondence to:</e5> M. Kanematsu Received: 25 August 1997/Revision accepted: 19 November 1997     

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     

Spiral CT for the detection of hepatocellular carcinomas: relative value of arterial- and late-phase scanning

Background: Spiral computed tomography (CT) can image the liver during arterial and late phases of contrast and optimize the evaluation of hypervascular tumor. The objective of this study was to evaluate the relative value of arterial- and late-phase spiral CT in the detection of hepatocellular carcinomas. Methods: Fifty-eight patients with hepatocellular carcinomas underwent two-phase spiral CT examination with 10-mm collimation at 10 mm/s table speed (Siemens Somatom Plus S), and 120 mL of contrast material (36 g iodine) was injected at the rate of 3 mL/s. CT images of hepatic arterial and late phases were obtained with a 35-s and 180-s delay, respectively. Results: In 58 patients, 111 hepatocellular carcinoma lesions were seen. The arterial phase detected 93 (84%) and the late phase 75 (68%) lesions (p < 0.01). The arterial phase detected more lesions in 11 patients, and the late phase dected more in two patients and an equal number in 45 patients. If lesions larger than 2 cm are excluded, the arterial phase detected 40 (74%) and the late phase 21 (39%) of 54 lesions (p < 0.001). Conclusion: The arterial phase of spiral CT greatly improves the detection of hepatocellular carcinoma when compared with the late phase. Received: 13 April 1995/Accepted: 22 May 1995     

Nonpathological focal enhancements on spiral CT hepatic angiography

Background: To assess the frequency and characteristics of nonpathological focal enhancements seen on spiral computed tomographic (CT) hepatic angiography (CTA). Methods: Spiral CTA and spiral CT arterial portography (CTAP) were performed in 31 patients with suspected liver malignancy prior to potential liver resection. The CTA images were retrospectively reviewed for focal enhancements by two radiologists. After determining nonpathological focal enhancements on CTA images based on the other radiographic tests, surgical exploration including intraoperative sonography, follow-up imagings, the frequency, size, site, and shape of nonpathological focal enhancements with CTA were assessed. Results: Thirty-six nonpathological focal enhancements with CTA from 4 to 23 (mean = 11.4) mm were seen in 14 (45.2%) of 31 patients. Thirteen (36.1%) of 36 nonpathological focal enhancements with CTA were not depicted with CTAP. Nonpathological focal enhancements with CTA were frequent in Couinaud segments III (27.8%), V (22.2%), and VI (19.4%). Twenty-three (63.9%) of 36 nonpathological focal enhancements were located in the edge of the liver. Shapes of 36 nonpathological focal enhancements with CTA included circular (n = 16), worm (n = 7), irregular (n = 6), dot (n = 6), and wedge (n = 1). Conclusion: In nearly half of patients, spiral CTA shows various shapes of small nonpathological focal enhancements more frequently in the liver edge. Received: 6 June 1996/Accepted: 14 July 1996     

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     

Mucin-hypersecreting papillary cholangiocarcinoma presenting as abdominal wall abscess: CT and spiral CT cholangiography

We describe CT findings of a case of mucin-hypersecreting papillary cholangiocarcinoma (MHPC), with extrahepatic bile leakage to the rectus abdominis muscle via the ligamentum teres hepatis forming an abdominal wall abscess. Endoscopic retrograde cholangiography was unsatisfactory. Spiral three-dimensional CT cholangiography was helpful in assessing the resectability of MHPC by offering anatomic details of the uninvolved biliary tree. Received: 20 February 1995/Accepted: 4 April 1995     

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     

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     

Radiographic findings of intractable gastric ulcers with H2-receptor antagonists

Background: To clarify the radiographic characteristics of intractable gastric ulcers with H₂-receptor antagonists. Methods: The radiographic findings at the time of starting treatment were compared between 42 patients with gastric ulcers that did not heal within eight weeks of starting treatment with H₂-receptor antagonists (the intractable group) and 58 patients whose ulcers healed within the eight-week period (the tractable group). Results: The following radiographic findings in the intractable group were observed at a significantly higher incidence than those in the tractable group and included: an ulcer located on the angle, linear ulcers, a greater depth, an uneven mound surrounding an ulcer, prominent folds' convergence, an overhanging gastric mucosa, an irregular ulcer base, a shortening of the lesser curvature and a U-shaped deformity of the angle. A multiple logistic regression analysis showed that the following three factors had a significant and independent delaying effect on healing: a U-shaped deformity of the angle, an uneven mound surrounding an ulcer and prominent folds' convergence. The relative risk of these factors were 12.7, 14.4 and 12.5, respectively. Conclusions: Intractable gastric ulcer with H₂-receptor antagonists can be predicted based on the characteristic radiographic findings at the start of treatment. Received: 23 December 1994/Accepted: 25 January 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     

Significance of hyperattenuating and contrast-enhancing hepatic nodules detected in the cirrhotic liver during arterial phase helical CT in pre–liver transplant patients: radiologic–histopathologic correlation of explanted livers

Background: Hyperattenuating nodules detected by arterial phase helical computed tomography (HCT) in patients with cirrhosis usually are believed to represent hepatocellular carcinomas (HCCs). We correlated HCT morphology of hyperattenuating hepatic nodules detected during arterial phase scans with the histopathology of explanted livers of patients with hepatic cirrhosis undergoing liver transplantation. Methods: Three hundred fifty-four patients had arterial and portal phase HCT performed before subsequent hepatic transplantation. Each patient received 180 mL of contrast by power injection at 5 mL/s. All hyperattenuating nodules detected on arterial phase HCT were assessed for morphology and evidence for contrast enhancement. Explanted livers in all patients were then sectioned at 10-mm intervals, and the histology of the nodules was correlated with the HCT findings. Results: Sixty-one hyperattenuating nodules were detected on the arterial phase HCT in 43 patients: 41 nodules were benign regenerating nodules (RN), three were dysplastic nodules (DP), and 17 were HCCs. Most RN/DP nodules were 5–20 mm in diameter, had distinct margins, were homogeneous, and were isoattenuating on precontrast, portal, and delayed scans. Thirty-six showed positive contrast enhancement and displayed a wide range of attenuation profiles. HCC nodules were 6–50 mm. All showed positive contrast enhancement and displayed a wide range of attenuation profiles. Conclusion: Hyperattenuating nodules seen on arterial phase HCT are likely to be RN/DP nodules. In many cases, it is not possible to distinguish between RN/DP and HCC. Thus, clinical decisions regarding inclusion criteria for transplantation based on CT morphology of liver lesions may be tenuous.     

Preoperative evaluation of Klatskin tumor: accuracy of spiral CT in determining vascular invasion as a sign of unresectability

Background: To assess the accuracy of spiral computed tomography (CT) in predicting the resectability of Klatskin tumor as determined by vascular invasion. Methods: Twenty-one consecutive patients with Klatskin tumor who had undergone laparotomy were included in this study. The preoperative thin-section (5-mm-thick) spiral CT scans of these patients were assessed for the surgical resectability of tumor by evaluating the vascular invasion. The criterion for vascular invasion indicating unresectability was the tumoral invasion of the proper hepatic artery or main portal vein or simultaneous invasion of one side of the hepatic artery and the other side of the portal vein. Results: All nine patients with tumors thought to be unresectable on the basis of CT findings had tumors that were unresectable at surgery (positive predictive value, 100%). Of 12 patients with tumors thought to be resectable, six had resectable tumors (negative predictive value, 50%). Spiral CT failed to detect small hepatic metastasis (n= 1), lymph node metastasis (n= 1), extensive tumor (n= 2) and variation of bile duct (n= 2), which precluded surgical resection. Conclusion: Spiral CT is a reliable method for detecting vascular invasion and unresectable tumors. However, it has limitations in detecting variations of the bile duct or the intraductal extent of tumor. Received: 24 November 1999/Accepted: 26 January 2000     

Rectus sheath hematoma: diagnostic classification by CT

A method of classification for hematomas of the rectus abdominis sheath (RSH) is proposed based on findings observed in CT in the 13 cases of RSH in the present study. Type I hematomas (five cases) are slight and do not require hospitalization. Type II (three cases) and type III (five cases) are moderate and severe hematomas, respectively, and do require hospitalization. The patients with type III hematomas were all undergoing anticoagulant therapy and presented with a picture of acute abdomen, and in all five cases blood transfusion was carried out. Ultrasonography and, in particular, CT permitted a correct diagnosis of RSH. RSH should be considered (anticoagulant therapy induced) in females with sudden abdominal pain to avoid unnecessary surgical intervention. Received: 1 May 1995/Accepted: 12 June 1995     

Detection of pancreatic adenocarcinoma: relative value of arterial and late phases of spiral CT

Background: Spiral computed tomography (CT) allows the pancreas to be imaged during peak contrast levels owing to the capability of fast data acquisition. The objective of this study was to evaluate the relative value of the arterial and late phases of spiral CT for detecting pancreatic adenocarcinomas. Methods: Twenty-two patients with pathologically proved pancreatic adenocarcinomas underwent two-phase spiral CT. The CT scans were performed with 5 mm collimation and 5 mm/s table speed. Images during the arterial and late phases were obtained at 30- and 180-second delays, respectively. The images of the arterial phase were compared with those of the late phase in terms of tumor conspicuity from surrounding pancreatic parenchyma and tumor detectability by means of a 3-point grading system: 1 (poor), 2 (fair), and 3 (good). Results: In terms of tumor conspicuity from surrounding pancreatic parenchyma, 16 lesions (73%) were good, 5 lesions (23%) were fair, and 1 lesion (4%) was poor during the arterial phase, whereas 6 lesions (27%) were good, 9 lesions (41%) were fair, and 7 lesions (32%) were poor during the late phase (p= 0.0007). The arterial phase was superior to the late phase in 16 patients (73%) and equal in 6 patients (27%). For tumor detectability, 18 lesions (82%) were good, 3 lesions (14%) were fair, and 1 lesion (4%) was poor during the arterial phase, whereas 10 lesions (45%) were good, 7 lesions (32%) were fair, and 5 lesions (23%) were poor during the late phase (p= 0.0033). For detectability, the arterial phase was superior to the late phase in 14 patients (64%) and equal in 8 patients (36%). Conclusion: The arterial phase of spiral CT is superior to the late phase, which is equivalent to conventional CT for detecting pancreatic adenocarcinoma. Received: 1 August 1995/Accepted: 12 September 1995     

Spiral CT of the abdomen after distention of small bowel loops with transparent enema in patients with Crohn's disease

Background: To evaluate the capability of a computed tomographic (CT) technique that combines distention of the small bowel loops with a transparent enema with contrast-enhanced spiral CT of the abdomen in patients with Crohn's disease. Methods: We evaluated the abdomen with spiral CT after distention of the small bowel loops with a transparent enema of methylcellulose in 40 patients consecutively referred for radiologic evaluation of Crohn's disease of the small bowel. Fluid was infused through a nasojejunal catheter with a peristaltic pump. Ultrasonography was used to prevent bowel overdistention and detect arrival of methylcellulose to the cecum. Contrast-enhanced spiral CT of the abdomen was then performed, and the degree of contrast enhancement and the thickness of the walls of the involved loops were evaluated. A series of 10 patients with retrograde distention of the last ileal loop from large bowel water enema was used as a control. The results of the CT were compared with those of conventional radiographic small bowel studies. Results: The normal small bowel wall was 1.9–2.5 mm thick (mean = 2.1 mm); density values of the normal enhanced wall varied between 25 and 60 HU (mean = 32 HU) and presented a homogeneous structure. Bowel segments involved by the disease were 4–12.5 mm thick (mean = 9.2 mm), had density values of 75–150 HU (mean = 105 HU), and showed a multilayered appearance. Compared with conventional radiography, CT detected longer lesions or additional segments involved by the disease process in 14 cases, 11 additional fistulas, two abscesses, and mesenteric changes in 21 cases. Conclusions: The small bowel CT enema technique provides good results in the study of patients with Crohn's disease and can be used to evaluate patients with advanced lesions. Received: 24 June 1998/Revision accepted: 27 January 1999     

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     

CT findings in symptomatic left paraduodenal hernia

Two cases of symptomatic, surgically proven left paraduodenal hernias were shown with computed tomography (CT) imaging. A small bowel loop was seen behind the pancreatic tail in one case, and a ring-oriented bowel loop was shown between the transverse colon and the left adrenal gland in the other. Received: 11 January 1995/Accepted: 4 February 1995