Intraductal ultrasonography for evaluating the patency of biliary metallic stents: correlation with cholangioscopic findings

Background: This is the first study to correlate intraductal ultrasonography (IDUS) with cholangioscopy in evaluating the patency of biliary metallic stents. Methods: The findings of IDUS (probe 2.0 mm in diameter and 20-MHz frequency) through a percutaneous transhepatic (n = 24) or transpapillary (n = 2) approach were retrospectively reviewed without other information. Criteria for IDUS are as follows: type 1, the inside of the stent is free; type 2, the inner edge is smooth; type 3, the inner edge is irregular; type 4, the inside of the stent is totally occupied; type 5, the solid echo is connected to the outside mass; type 2+D, a hypoechoic line is seen between the bile duct wall and the inside solid component and the inner edge of the bile duct wall is smooth; type 3+D, an irregular hypoechoic line is seen between the bile duct wall and the inside solid component. Results: In the control group (n = 11), IDUS showed type 1 (n = 9) or type 2 (n = 2). In the occluded group (n = 15), when IDUS showed type 3 or 5, the patients (n= 5) required additional stents (n = 3), microwave coagulation of the tumor (n= 1), or transient external drainage (n= 1). When IDUS showed type 4 (n = 5), after washing, the findings changed to type 2+D (n = 4). When IDUS after washing showed a smooth inner edge (type 2+D), the patients were treated without additional stents more frequently than the other groups (eight of nine vs. two of six), a significant distinction (p < 0.05). Conclusion: IDUS is useful in assessing the patency of metallic stents. When the inside of the stent is totally occupied, however, examination after washing is necessary. Received: 19 May 2000/Accepted: 28 June 2000     

CT portography by direct intrasplenic contrast injection: a new technique

Background: The evaluation of percutaneous contrast injection into splenic parenchyma as an alternative technique for computed tomographic (CT) portography in the preoperative assessment of primary hepatobiliary tumors. Methods: Thirty-two patients underwent a nonenhanced CT scan of the liver, after which a 19-gauge, 10-cm-long needle was introduced into the splenic parenchyma under CT guidance. One hundred forty milliliters of contrast medium (200 mgI/mL; 28 g/I) were injected through this needle: first, a 20-mL bolus (in 5 s) and then 2 mL/s for 60 s. At the end of the bolus injection (5 s), 8-mm-thick contiguous axial scans of the liver were obtained. Results: The success rate of the procedure was 93.7% (30/32; two technical failures). The average time required for the entire study was 13 min and 50 s (range = 7 min 53 s to 25 min 17 s). Hepatic parenchymal enhancement was good in 24/30 (80%), moderate in 3/30 (10%), and unsatisfactory in caudal sections of the liver in 3/30 (10%). Artifactual perfusion defects were seen in 4/30 (13%) due to inadvertant injection of small quantities of air. Intrasplenic subcapsular contrast accumulation occurred in 56.2% (18/32; minimal 15, moderate 3), extrasplenic contrast leakage in 12.5% (4/32), and left shoulder pain in 18.7% (6/32). No major complications were observed. Conclusions: Direct intrasplenic contrast injection for CT portography is a simple, effective, and safe technique with a high success rate and requires significantly less time and lower doses of contrast medium; it also eliminates angiography, indwelling arterial catheters, and patient transfers from angiography to the CT area. Received: 5 November 1997/Accepted after revision: 11 February 1998     

Endoscopic surveillance of the ileoanal pouch following restorative proctocolectomy for familial adenomatous polyposis

Persistence of underlying disease in the residual rectal mucosa and anal transition zone occurs following mucosectomy with either a hand-sewn anastomosis or a double-stapled anastomosis. Furthermore, recent reports have suggested an increased incidence of neoplasia in the pouch body. For this reason, endoscopic surveillance is performed not only as a screening tool to detect significant intraepithelial neoplastic lesions but also with secondary therapeutic intent aimed at reducing the adenoma burden within the ileoanal pouch. Conventional endoscopic assessment of the ileoanal pouch can be challenging. In the future, novel adjunctive endoscopic technologies such as magnification endoscopy and confocal endomicroscopy may improve our diagnostic and therapeutic management of this group.     

Hepatic artery embolization for postoperative hemorrhage in upper abdominal surgery

Background: The purpose of this study was to evaluate angiographic findings and radiologic and clinical results of transcatheter arterial embolization (TAE) of the hepatic artery for hemorrhage after upper abdominal surgery. Methods: Ten patients (nine male, one female, mean age = 63.5 years) with postoperative hemorrhage underwent emergency hepatic artery embolization. We retrospectively analyzed the angiographic findings and the effectiveness of TAE. Results: Angiography demonstrated pseudoaneurysms (n = 6) and extravasation (n = 5). Portal veins were not compromised in any patient. The bleeding points were at the gastroduodenal artery (n = 3), proper hepatic artery (n = 3), right hepatic artery (n = 2), left hepatic artery (n = 1), and intrahepatic artery (n = 2). Embolization was performed at the extrahepatic site (n = 6) and intrahepatic site (n = 4). TAE was successful in eight patients. Hemostasis was achieved in eight patients. Two patients in whom TAE was not successful died of bleeding after TAE. In six patients whose collateral arteries were visualized at TAE, hypoxic hepatic failure was avoided and the patients had a favorable clinical course. Conclusion: TAE is a useful treatment for postoperative hemorrhage, but the presence of collateral arteries at the time of TAE can affect the patients' prognoses.     

Altered flow dynamics of intravascular contrast material to the liver in superior vena cava syndrome: CT findings

Background: To evaluate the findings of altered flow dynamics in the livers of patients with obstruction of superior vena cava (SVC) on helical computed tomography (CT). Methods: In six patients (age range = 28–80 years) with SVC obstruction, CT findings were retrospectively reviewed to identify the abnormal enhancement patterns of the liver and the relation with the extrahepatic collateral vessels and hepatic vessels. Results: Abnormal hepatic enhancement was observed in the following four (A–D) portions: (A) anterior portion of segment IV (n = 5), (B) subdiaphragmatic portion of the liver (n = 4), (C) posterior portion of the right lobe (bare area; n = 1), and (D) lateral segment of the left lobe (n = 2). Two major collateral pathways to the liver were demonstrated as follows: A and D → from the umbilical vein to the left portal vein, and B and C → from the subcapsular vein to the bare area of the liver or to the hepatic veins. On helical CT, these collateral pathways were also clearly visualized. Conclusion: When these abnormal enhancements of the liver on CT are recognized within the liver, these findings indicate diversion of contrast material into collateral pathways to the liver with SVC obstruction. Received: 31 March 1999/Revision accepted: 25 June 1999     

Gadopentetate dimeglumine as an oral negative gastrointestinal contrast agent for MRCP

Background: We investigated the feasibility of using intravenous magnetic resonance (MR) contrast agent as a gastrointestinal oral negative contrast agent to null the bowel signal during MR cholangiopancreatography (MRCP). Methods: In the first part of the study, a phantom study was performed to select the optimal concentration of MR contrast agent to be used as an oral negative contrast agent in MRCP. In the second part of the study, 23 consecutive patients suffering from different pancreaticobiliary diseases were imaged with a single-shot fast spin-echo pulse sequence. The data acquisition was started without oral contrast agent and then repeated with oral contrast agent. From the MR images taken with and without oral contrast agent, the gallbladder, cystic duct, common bile duct, and pancreatic duct were assessed and graded by two radiologists. Results: The oral contrast agent was tolerated well by all patients. In all patients the high signal intensity from the intestinal fluid was completely suppressed. The depictions of the gallbladder and cystic duct were slightly and moderately improved, respectively, whereas the depictions of the common bile duct and pancreatic duct were markedly improved by the oral contrast agent administration. Conclusion: Diluted intravenous MR contrast agent can be an effective and safe oral negative contrast agent in eliminating signal intensity of the gastrointestinal tract, thus improving the depiction of the biliary system in MRCP. Received: 14 September 1999/Revision accepted: 12 January 2000     

MRI of the abdomen with positive oral contrast agents for the diagnosis of inflammatory small bowel disease

Magnetic resonance imaging (MRI) is being used more often in the evaluation of inflammatory bowel diseases. A prerequisite for adequate image quality is the oral application of contrast medium, which can be administered with different modalities. Positive and negative oral contrast media can be used; in terms of diagnostic efficacy, there appears to be no relevant differences between them. Sequences usually are acquired using breath-hold or respiration-triggered protocols. The underlying principle is visualization of circumscribed thickening of the intestinal wall, which shows a pathologic pattern of contrast medium uptake. The available data suggest that MRI is equally as effective as enteroclysis in the primary diagnosis of Crohn's disease and actually more sensitive in the detection of extraintestinal manifestations such as fistulae or abscesses. Supporters of the method predict that MRI will replace enteroclysis in the long term.     

MR imaging of advanced gastric cancer: comparison of various MR pulse sequences using water and gadopentetate dimeglumine as oral contrast agents

Background: To evaluate clinical usefulness of oral contrast agents (gadopentetate dimeglumine and water) and to assess proper magnetic resonance (MR) imaging in evaluating advanced gastric cancer (AGC) by comparing different MR imaging techniques. Methods: Fifteen patients with AGC were imaged with a 1.0-T MR imager and body-array coil. All patients underwent surgery or laparascopic biopsy. Fast low-angle shot (FLASH), half-Fourier single-shot turbo spin-echo (HASTE), and true fast imaging with steady-state precession time (FISP) images were obtained after ingestion of 900 mL tap water in each patient, followed by postcontrast FLASH images after additional ingestion of gadopentetate dimeglumine (Gd-DTPA). Qualitative analysis including T-staging of AGC and scoring of imaging quality and quantitative analysis were performed prospectively. Results: In image quality and diagnostic accuracy of T-staging, FLASH imaging showed results slightly superior to those of other imaging modalities, and there was no great difference between using water and Gd-DTPA as an oral contrast agent. As for cancer-to-gastric lumen contrast-to-noise ratio (CNR), HASTE and true FISP imaging were superior to FLASH imaging with Gd-DTPA (p < 0.0001). In cancer-to-pancreas CNR, FLASH imaging without Gd-DTPA showed the best result. Conclusions: The use of Gd-DTPA as a positive contrast agent may not be imperative, and T1-weighted FLASH imaging in combination with true FISP imaging with ingestion of tap water can be very useful in evaluating AGC with MR imaging. Received: 29 October 1998/Revision accepted: 27 January 1999     

Catheter dislodgement of percutaneous transhepatic biliary drainage: identification of role of puncture sites and catheter sheath

Background: To identify the appropriate puncture points in the bile duct to avoid catheter dislodgement. Methods: Percutaneous transhepatic biliary drainage catheters (n = 300) were placed in 242 patients. The frequency of dislodgement (complete dislodgement or bending of the catheter) was prospectively investigated. The puncture site of the bile duct was classified on the ultrasonographic findings as follows: Main-B3, main branch of the lateral inferior segment; peripheral-B3, peripheral branch of the lateral inferior segment; B2, lateral superior segment; left hepatic duct, proximal portion of the left hepatic duct; B8, anterior superior segment; B5, anterior inferior segment; B5 + 8, main bile duct of the anterior segment; B6, bile duct of posterior inferior segment; and right hepatic duct, proximal portion of the right hepatic duct. Results: When a catheter without an outer sheath was used, catheter dislodgement in peripheral-B3 (2/11, 18%) was more common than in main-B3 (0/32, 0%; p < 0.05). In B5, catheter dislodgement (6/12, 50%) was more frequent than in B8 (3/20, 15%; p < 0.05) and in B6 (0/14, 0%; p < 0.005). When a catheter with an outer sheath was used, catheter dislodgement (2/207, 1%) was rare. Conclusion: Drainage from B5 and peripheral-B3 is associated with a high risk of dislodgement of the catheter. A catheter with an outer sheath was useful to prevent catheter dislodgement. RID=" ID=" <E5>Correspondence to:</E5> K. Tamada Received: 8 February 2000/Accepted: 8 March 2000     

Helical CT of the small bowel with an alternative oral contrast material in patients with Crohn disease

Background: We assessed the usefulness of helical computed tomography (CT) with a negative oral contrast material for detecting Crohn disease. Methods: Thirty-eight patients with proven Crohn disease were examined. We administered a large volume of a new negative oral contrast material (Mucofalk suspended in water) and then proceeded with helical CT scanning. This technique is an alternative to CT and conventional enteroclyses that use a nasojejunal tube. Two radiologists interpreted the scans, and patients were interviewed about their tolerance of the procedure. We created multiplanar reformatted images in all cases. Potential of small bowel distention by Mucofalk was evaluated by two observers on a three-point scale, and interobserver agreement was calculated with κ statistics. Results: All patients who underwent enteroclysis stated that CT was the more comfortable method, the taste of the peroral contrast medium was considered good by 52.6% and acceptable by 47.4%. Small bowel distention was excellent in 55% of cases, moderate in 26%, and poor in 19%, with an interoberserver agreement of 78%. CT findings correlated with enteroclysis in 27 patients who underwent both methods. Analysis of CT versus enteroclysis showed a sensitivity of 89% for CT versus 78% for small bowel enteroclysis. Conclusion: Mucofalk CT is a simple, rapid, noninvasive, and accurate method of evaluating extramucosal manifestations of Crohn disease. The tubeless procedure improved patients' comfort and decreased time, cost, and radiation exposure.     

Per-rectal contrast material for abdominal CT: usefulness of administration with an automatic injector

Adequate distention of the gastrointestinal tract is essential for the best quality image in abdominal computed tomography. We introduce a new technique for per-rectal administration of contrast material with the use of an automatic injector. With this technique, more contrast material can be inserted and thus adequately distend the colon, including the proximal colon. Received: 15 September 2000/Revision accepted: 27 December 2000     

Cervical carcinoma: efficacy of thin-section oblique axial T2-weighted images for evaluating parametrial invasion

Background: To investigate the efficacy of thin-section oblique axial T2-weighted images in the assessment of parametrial invasion by cervical carcinoma. Methods: One hundred parametria of 50 patients with cervical carcinoma were evaluated with pathologic correlation. We compared the sensitivity, specificity, and diagnostic accuracy in the assessment of parametrial invasion by cervical carcinoma between axial T2-weighted images and thin-section oblique axial T2-weighted images. Results: Thin-section oblique axial T2-weighted images provided accurate cross sections of the cervix with excellent detail and detected parametrial invasion more accurately than did axial T2-weighted images showing cross sections of the trunk. Although the sensitivity, specificity, and accuracy for parametrial invasion were 46.4%, 91.7%, and 79.0%, respectively, on axial T2-weighted images, the corresponding values were 67.9%, 97.2%, and 89.0%, respectively, on thin-section oblique axial T2-weighted images. There were statistically significant differences in the sensitivity (p = 0.014), specificity (p = 0.046), and accuracy (p = 0.002) in detecting parametrial invasion between these two types of images. Conclusions: Thin-section oblique axial T2-weighted images are useful for the assessment of parametrial invasion by cervical carcinoma. Received: 11 September 1998/Accepted: 2 December 1998     

CT findings of isolated small bowel angioedema due to iodinated radiographic contrast medium reaction

We report three cases of small bowel angioedema that showed circumferential wall thickening of the small bowel loops during infusion of iodinated contrast media. Follow-up small bowel series or computed tomography confirmed the normalized small bowel loops. When significant wall thickening of the long segment of the small bowel during infusion of contrast media is seen, radiologists should consider the possibility of isolated small bowel angioedema in spite of its rarity. Received: 4 February 1998/Accepted: 11 March 1998     

Pancreaticobiliary carcinoma associated with a large choledochal cyst: role of MRI and MR cholangiopancreatography in diagnosis and preoperative assessment

The role of magnetic resonance (MR) imaging and MR cholangiopancreatography is demonstrated in a case of pancreaticobiliary carcinoma associated with a large choledochal cyst. The size of the cyst presented considerable difficulty in evaluation with both endoscopic retrograde cholangiopancreatography and computed tomography. Received: 10 April 1998/Accepted: 20 May 1998     

Dynamic enhancement of upper abdominal organs in normal volunteers with MRI and effects of contrast dose reduction

Background: To quantify enhancement parameters of the upper abdominal organs over time during magnetic resonance (MR) examinations and to evaluate the effect of a dose reduction of contrast medium on these parameters. Methods: Ten volunteers underwent two separate dynamic enhanced MR examinations with 0.1 and 0.075 mmol/kg of contrast medium, respectively. Breath-hold gradient-echo T1-weighted images were acquired every second for 118 s followed by delayed images. The percentages of enhancement, the time to maximum enhancement, and the area under the time-versus-enhancement curve were calculated for each organ. Results: The mean times to maximum percentage of enhancement were less than 25 s for the pancreas, kidneys, and spleen and 50 s for the liver. The mean values of maximum percentage of enhancement for the standard/reduced doses were 72%/62% (pancreas), 165%/155% (kidneys), 114%/87% (spleen), and 67%/53% (liver). This difference was significant when liver enhancement was considered (p= 0.02). In addition, when the areas under the time-versus-enhancement curves were compared, the difference between the standard dose and reduced dose was significant for all organs tested (p < 0.05). Conclusions: Dynamic scanning of the upper abdomen should start early after contrast injection. Injection parameters should be standardized to capture arterial and venous enhancements in liver examinations. A 25% dose reduction did not significantly affect peak enhancement (except for the liver) but did significantly reduce overall enhancement. Received: 8 September 1998/Revision accepted: 13 January 1999     

Hepatic CT enhancement: effect of the rate and volume of contrast medium injection in an animal model

Background: To evaluate the relative effect of rate of injection and volume of contrast medium on aortic, portal, and hepatic enhancement during computed tomography (CT). Methods: Thirty-eight nonincremental CT examinations were performed in three mini-pigs by using a combination of three different volumes (1.5, 2, and 3 mL/kg) and five different rates (1.5, 3, 4.5, 6, and 7.5 mL/s) of contrast material injection. Time-density enhancement curves of the aorta, portal vein, and liver were plotted over time for each rate of injection, each volume of contrast, and each volume–rate combination. In addition, aortic, portal, and liver peak enhancements, time-to-peak enhancements, optimal scanning intervals, and contrast enhancement indices were calculated for each volume–rate combination. Results: Higher rates of injection increased peak aortic enhancement but had no effect on peak portal or hepatic enhancement. This result may be explained by the dilution of the bolus of contrast medium in the splanchnic circulation. When the results of a 6-mL/s injection of 1.5 mL/kg of contrast material were compared with a 3-mL/s injection of 2 mL/kg, maximum aortic enhancement increased by 32%, whereas maximum liver enhancement decreased by 35%. Conclusion: An increase in the rate of contrast injection results in an increase of peak aortic enhancement even when the total iodine load is decreased. However, an increase of the rate of contrast injection does not increase maximum liver enhancement, which is related to the total iodine dose injected. Therefore, one cannot compensate a decrease in the iodine load by an increase in injection rate in contrast-enhanced CT of the liver. Received: 3 September 1997/Revision accepted: 13 January 1999     

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     

Omental infarction: report of three cases and review of the literature

Omental Infarction, the end result of impaired perfusion to the greater omentum, is a rare entity (JBCM Puylaert, Radiology 1992;185:169–172). We recently encountered three patients in whom computed tomography (CT) showed the characteristic findings of omental infarction. The diagnosis was subsequently confirmed intraoperatively and pathologically in two of the cases. The third case showed partial resolution on follow-up computed tomography. All three cases are presented with a brief review of the literature. Received: 9/19/96/Accepted: 10/30/96     

A primary carcinoid tumor of the kidney: a case report and review of the literature

Background: Primary carcinoids are found mostly in the gastrointestinal tract. Primary carcinoid tumor of the kidney is rare; only 28 patients have been reported. Because of the rarity of the lesion, its radiological and clinicopathological features are not well characterized. At the same time, its prognosis and histogenesis is unknown. Methods: A 62-year-old patient presented with a carcinoid tumor on the isthmus of the horseshoe kidney. Radiological, clinicopathological, and immunohistochemical tests were performed. The tumor was resected. Results: Two years later, metastasis were observed in the liver. The metastasis were treated with percutaneous ethanol sclerotherapy (PET). Conclusions: To our knowledge, this is the first case of primary renal carcinoid tumor present on the isthmus of the horseshoe kidney and the first case of carcinoid liver metastasis to be treated with PET. Received: 21 August 1995/Accepted: 31 August 1995