Saline-filled appendiceal ultrasonography in clinically equivocalacute appendicitis

Background: To establish the value of saline-filled appendiceal ultrasonography in the the diagnosis of clinically equivocal acute appendicitis. Methods: Saline-filled ultrasonography was performed in 43 patients with an equivocal clinical diagnosis of acute appendicitis. Results: Sonography diagnosed 31 of 32 patients without acute appendicitis (97%). A normal appendix was visualized in 15 patients (47%), and we identified a normal appendix in 15 of 22 patients (68%) in whom the colon was cleansed with Golytely?. Sonography diagnosed 10 of 11 patients with acute appendicitis (91%). In three of 10 patients, the findings corresponded to sonographic pitfalls. Conclusion: Saline-filled appendiceal ultrasonography enables the detection of a normal appendix and may overcome sonographic pitfalls in acute appendicitis. Received: 2 June 1995/Accepted: 18 July 1995     

Synchronous mucinous tumors of the ovary and the appendix associated with pseudomyxoma peritonei: CT findings

Background: To present the computed tomographic (CT) findings of synchronous mucinous tumors of the ovary and the appendix associated with pseudomyxoma peritonei (PMP). Methods: Imaging studies, mainly abdominal CT scans, of three women aged 49–75 years were reviewed. Attention was directed to the ovarian masses, peritoneal seeding, and the presence of an appendiceal mucocele. Results: The ovarian tumors and the appendiceal mucocele were clearly demonstrated in two cases, and they were part of the extensive PMP in the third patient. Ascites was found in all cases, with internal septation in one. Associated scalloping of the liver margins and hypodense peritoneal implants, with extensive bowel involvement, were seen in another one. Pathologically, there was one case of right ovarian mucinous cystadenoma and villous adenoma of the appendix, one case of right ovarian and appendiceal mucinous cystadenocarcinoma, and one case of bilateral metastatic ovarian implants of appendiceal mucinous cystadenocarcinoma. PMP was found in all. In the case with benign tumors of the ovary and the appendix, the PMP was classified as a benign mucinous spillage. This patient returned 33 months after surgery with PMP, in which epithelial cells were found. Conclusions: Radiologists should be familiar with the clinical occurrence of synchronous mucinous tumors of the ovary and the appendix associated with PMP and with the typical CT findings of the latter two entities. Alternatively, when the imaging findings suggest ovarian cystic tumor with PMP, the radiologist should be alerted to the probability of a clinically unsuspected appendiceal mucocele and should search for it. Received: 10 August 1999/Accepted: 22 September 1999     

Sonography of acute appendicitis in pregnancy

Background: Clinical evaluation of acute appendicitis is difficult in pregnant patients. Delay in diagnosis is associated with increased fetal mortality. The purpose of our study was to assess the value of sonography in the diagnosis of acute appendicitis in pregnant women. Methods: We obtained sonograms in 22 pregnant women suspected of acute appendicitis. All sonograms were performed using graded-compression to detect an enlarged appendix. The sonographic criteria for acute appendicitis were detection of a noncompressible blindended and tubular multilayered structure of maximal diameter greater than 6 mm. Results: The sonographic findings were correlated with surgical findings in seven cases and clinical follow-up in 15 cases. Acute appendicitis was diagnosed by sonography in three of 22 patients, and in all but one was confirmed by surgical and pathologic findings. In the remaining 19 patients, 15 improved on clinical follow-up; three were shown to have a normal appendix at surgery and one had focal acute inflammation at the tip of the appendix. Conclusions: Our experience suggests that graded-compression sonography is a useful procedure in pregnant patients suspected of acute appendicitis and has a similar accuracy as in nonpregnant women, especially in the first and second trimester.     

Perforations of the rectosigmoid colon induced by cleansing enema: CT findings in 14 patients

Background: We report the computed tomographic (CT) features of colorectal perforations caused by cleansing enema. Methods: We reviewed the medical records and CT studies of all patients with colorectal perforations caused by a cleansing enema. Results: Fourteen patients (10 men, four women; average age = 80 years) were included in the study. The most common presenting symptoms were severe abdominal pain and fever. CT was performed within 48 h after the event in most patients. Extraluminal air in the perirectal fat was the most frequent finding on CT and was present in all patients. Additional findings were extraperitoneal (n = 9), intraperitoneal (n = 3) and /or subcutaneous (n = 3) air, free fluid (n = 9), extraluminal feces (n = 8), and focal bowel wall thickening (n = 4). No leak of contrast from the rectum was observed in any patient including the one patient in whom contrast was administered rectally. Ten patients were treated by surgery; five recovered and the other five died. The other four patients were treated conservatively and all four died. Conclusion: The diagnosis of colorectal perforation can be made on CT. Because the diagnosis is not always suspected by the clinician, the radiologist may be the first to suggest it. Therefore, the radiologist should be familiar with the CT features of a potentially lethal, rectally induced perforation. Received: 19 April 2001/Revision accepted: 4 July 2001     

急性阑尾炎的CT表现

目的 探讨急性阑尾炎的CT表现。方法 对68例手术、病理证实为急性阑尾炎病人的腹部CT资料进行回顾性分析，对阑尾大小、有无阑尾结石、阑尾周围及盲肠末端的改变作了观察、分析。结果 68例中61例CT诊断为急性阑尾炎，7例假阴性，CT诊断急性阑尾炎的敏感性为89．7％。急性阑尾炎的CT表现主要有阑尾增粗(76．5％)，阑尾结石(29．4％)，阑尾周围炎性改变(66．2％)，阑尾脓肿(13．2％)，蜂窝织炎(10．3％)，盲肠末端肠壁增厚(7．4％)和局部淋巴结肿大(5．9％)。结论 急性阑尾炎可出现多种CT表现，熟悉这些表现有助于提高CT诊断阑尾炎的准确性。     

Fascioliasis: US, CT, and MRI findings with new observations

Background: The purpose of this study is to describe the ultrasonographic (US), computed tomographic (CT), and magnetic resonance imaging (MRI) findings in fascioliasis and to emphasize the impact of radiology in diagnosis. Methods: Radiologic findings in 23 consecutive patients with fascioliasis were prospectively recorded. All patients had at least one US and CT examination, and 10 of them were studied by MRI. All diagnoses were confirmed by serologic methods. In the first three cases, initial diagnosis was reached by microscopic demonstration of the parasites' eggs in bile obtained by US-guided gallbladder aspiration. Results: In the hepatic phase of fascioliasis, multiple, confluent, linear, tractlike, hypodense, nonenhancing hepatic lesions were detected by CT. On US, the parasites could be clearly identified in the gallbladder or common bile duct as floating and nonshadowing echogenic particles. MRI showed the lesions as hypo- or isointense on T1-weighted images and as hyperintense on T2-weighted images. Conclusions: CT findings in the hepatic phase and US findings in the biliary phase are characteristic of fascioliasis. Because clinical and laboratory findings of fascioliasis may easily be confused with several diseases, radiologists should be familiar with the specific radiologic findings of the disease to shorten the usual long-lasting diagnostic process. Received: 15 December 1999/Accepted: 26 January 2000     

Intestinal malrotation as an incidental finding on CT in adults

Background:Intestinal malrotation in adults is usually an incidental finding on computed tomography (CT). We present the CT findings of 18 adult patients with malrotation and discuss the clinical implications. Methods: Abdominal scans of 18 patients (12 women, six men; age range = 15–79 years) with intestinal malrotation were reviewed. Special attention was directed to the location of the superior mesenteric vessels, the location of the small and large bowels, the size of the uncinate process, the situs definition, and additional anomalies. Results: The malrotation was an incidental finding in all but one patient. The malrotation was type Ia in 17 patients and IIc in the one symptomatic patient. The superior mesenteric vessels were vertically oriented in 10, inverted in two, normally positioned in four, and mirror imaged in two cases with situs ambiguus. All patients had aplasia of the pancreatic uncinate process, five had a short pancreas, and two had a preduodenal portal vein. Fourteen patients had a normal situs and four had heterotaxia. Seven patients had polysplenia, six of which with associated inferior vena cava anomalies. Conclusions: Intestinal malrotation can be diagnosed on CT by the anatomic location of a right-sided small bowel, left-sided colon, an abnormal relationship of the superior mesenteric vessels, and aplasia of the uncinate process. Awareness of these abnormalities is necessary to diagnose this anomaly. It should be sought in patients with a situs problem, inferior vena cava anomalies, polysplenia, or preduodenal portal vein. Although usually an incidental finding, it is important to diagnose such a malrotation because it may cause abdominal symptoms. Also, knowledge of associated vascular anomalies is important when abdominal surgery is planned. Received: 1 October 1998/Revision accepted: 27 January 1999     

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     

Urinary calculus: IVU vs. CT renal stone? A critically appraised topic

Background We wondered whether noncontrast CT performs better than the intravenous urogram (IVU) in the detection of urinary calculi. Methods A comprehensive search of the literature was undertaken in order to answer the above question. Both primary and secondary sources of evidence were searched. The retrieved evidence was then appraised. Results The strongest evidence was in a meta-analysis by Worster and colleagues (level 1a evidence according to the Oxford/CEBM levels of evidence). This was an analysis of four studies with a total of 296 patients who underwent intravenous urogram and noncontrast CT. This study shows that CT has better diagnostic performance than IVU for the detection of urinary stones. Conclusions The literature suggests that CT should be utilized in preference to IVU for patients with suspected urolithiasis.     

Renal and perirenal space involvement in acute pancreatitis: spiral CT findings

Background: This study was conducted to estimate the prevalence and morphologic computed tomographic (CT) features of renal and perirenal space abnormalities in acute pancreatitis in correlation with the severity of pancreatitis. Methods: One hundred fifty-nine contrast-enhanced CT scans of 100 consecutive patients with acute pancreatitis were retrospectively and independently reviewed by three observers. All CT images were obtained using contrast-enhanced helical CT (collimation width = 5 mm, table increment = 7 mm/s, reconstruction interval = 5 mm, scan delay time = 30–50 s). Additional maximized images (field of view = 260 mm) of the perirenal space were available for review. All CT scans were scored with the CT Severity Score Index: pancreatitis was graded as mild (0–2 points), moderate (3–6 points), and severe (7–10 points). Interobserver agreement for both the severity score and the presence of renal and perirenal involvement was calculated. Correlation between the prevalence of complications and the degree of pancreatitis was estimated. Results: CT scans were graded as mild (n= 59), moderate (n= 82), and severe (n= 18). Abnormalities detected included perirenal stranding (n= 37 patients, 26 bilateral), perirenal fluid collections (n= 10 patients, one bilateral), ureteral encasement (n= 2 patients), renal vein thrombosis (n= 1 patient), and renal parenchymal abnormalities (n= 1 patient). The interobserver agreement range for scoring the degree of pancreatitis and the overall presence of abnormalities was 75.5–79.2% and 59.8–100%, respectively. Except for stranding of the perirenal fat, no statistically significant differences between the presence of abnormalities and the severity of pancreatitis (moderate or severe) was observed with Fisher's exact test. Also, no preferential left-sided localization of complications was observed. Conclusions: The incidence of renal and perirenal complications from acute pancreatitis is higher than previously estimated (7%). We found no significant correlation between the prevalence of major complications and the severity of pancreatitis. These findings are important because these complications may have an impact on therapeutic strategy and can affect prognosis. Received: 31 March 1999/Revision accepted: 25 August 1999     

Evaluation of pancreatic carcinoma with FDG PET

Background: To assess the diagnostic usefulness and clinical impact of positron emission tomography with [F-18]fluorodeoxyglucose (FDG PET) on the management of patients with known or suspected pancreatic carcinoma. Methods: Attenuation-corrected FDG PET was performed in 20 patients (12 male, eight female) with pancreatic carcinoma at the time of initial diagnosis (n = 7), for tumor surveillance after Whipple surgery (n = 11), and for reevaluation after chemoradiation therapy (n = 2). Visual analysis of PET images were correlated with the results of abdominal computed tomography (CT) and carbohydrate antigen (CA) 19-9 serum tumor marker level that were obtained within 1 month of the PET study. Diagnostic validation was by histology in nine patients and by clinical or radiologic follow-up (5–48 months) in 11 patients. Changes in therapeutic management that were prompted by PET were tabulated. Results: PET was concordant with the findings of abdominal CT in 14 patients (13 true positive, 1 true negative). PET detected clinically unsuspected lung lesions, confirmed subsequently by a chest CT, in one of these 14 patients. PET was discordant with CT in six patients. PET detected tumor recurrence in three patients in this group (15% of total) with nondiagnostic CT findings and elevated CA 19-9 serology. In two of these three patients, chemotherapy with gemcitabine was initiated based on PET localization of disease. Tumor was confirmed in the remaining one of the three patients at autopsy shortly after the PET study. FDG localization in a displaced loop of bowel resulted in an apparent false-positive hepatic lesion in one of six patients in the discordant group. PET underestimated the extent of metastatic disease in the remaining two of six patients due to hyperglycemia. Conclusion: In patients with suspected pancreatic carcinoma at the time of initial presentation, PET is complementary to abdominal CT and allows detection of unsuspected distant metastases. In patients with suspected recurrent pancreatic carcinoma, based on elevated or rising CA 19-9 serology, PET can localize the disease when abdominal CT is nondiagnostic as a result of posttherapy anatomic alteration. Imaging evaluation with PET may impact the clinical management of patients with pancreatic carcinoma. Received: 1 August 2000/Accepted: 20 September 2000     

Sonography in the Evaluation of Acute Appendicitis

Objective. The purpose of this study was to evaluate the negative predictive value (NPV) of sonography in the diagnosis of acute appendicitis. Methods. Right lower quadrant sonograms of 193 patients (158 female and 35 male; age range, 3–20 years) with suspected acute appendicitis over a 1‐year period were retrospectively reviewed. Sonographic findings were graded on a 5‐point scale, ranging from a normal appendix identified (grade 1) to frankly acute appendicitis (grade 5). Sonographic findings were compared with subsequent computed tomographic (CT), surgical, and pathologic findings. The diagnostic accuracy of sonography was assessed considering surgical findings and clinical follow‐up as reference standards. Results. Forty‐nine patients (25.4%) had appendicitis on sonography, and 144 (74.6%) had negative sonographic findings. Computed tomographic scans were obtained in 51 patients (26.4%) within 4 days after sonography. These included 39 patients with negative and 12 with positive sonographic findings. Computed tomography changed the sonographic diagnosis in 10 patients: from negative to positive in 3 cases and positive to negative in 7. Forty‐three patients (22.2%) underwent surgery. The surgical findings were positive for appendicitis in 37 (86%) of the 43 patients who had surgery. Patients with negative sonographic findings who, to our knowledge, did not have subsequent CT scans or surgery were considered to have negative findings for appendicitis. Seven patients with negative sonographic findings underwent surgery and had appendicitis; therefore, 137 of 144 patients with negative sonographic findings did not have appendicitis. On the basis of these numbers, the NPV was 95.1%. Conclusions. Sonography has a high NPV and should be considered as a reasonable screening tool in the evaluation of acute appendicitis. Further imaging could be performed if clinical signs and symptoms worsen.     

CT evaluation of the resectability of gastric cancer postchemotherapy

Background: To determine the accuracy of CT in the postchemotherapy assessment of resectability of gastric cancer. Methods: Thirty patients deemed to have unresectable gastric cancer on CT were studied. This was verified at laparotomy in 10 of these patients. Following initial assessment, all received three to eight cycles of chemotherapy aiming for disease control and potential resection. Serial CT examinations, endoscopy, and biopsy were performed after the fourth, sixth, and eighth cycle of treatment. The primary tumor and lymph nodes seen on CT were compared with operative findings. Results: After completion of chemotherapy, CT findings were correct in 23 patients. Fourteen of them had operable tumors and nine were inoperable. However, the CT findings were either equivocal or incorrect in the remaining seven patients. Conclusion: Chemotherapy is now able to downstage a previously inoperable gastric cancer, and CT is an accurate method in identifying those patients who can proceed to resection. Received: 24 October 1994/Accepted after revision: 6 April 1995     

多层螺旋CT三维重建对急性阑尾炎的诊断价值

目的探讨多层螺旋CT三维重建对急性阑尾炎的诊断价值。方法搜集58例临床拟诊为急性阑尾炎的病例,行多层螺旋CT检查,并经工作站进行多平面重建及曲面重建,分析其CT表现并将诊断结果与手术病理结果对照。结果58例病人中,诊断急性阑尾炎53例,升结肠癌2例,右侧腹股沟疝2例,假阴性1例。急性阑尾炎多层螺旋CT的主要征象及出现频率如下：阑尾肿大增粗（管腔直径〉6mm）占96．2％,阑尾结石占17．0％,回盲部壁增厚占30．1％,阑尾周围炎占60．4％,阑尾周围脓肿占15．1％,阑尾穿孔占9．4％。结论急性阑尾炎有典型的CT征象,多层螺旋CT三维重建图像后处理技术能多方位显示阑尾本身及其周围组织情况,在急性阑尾炎的诊断中具有较高的临床应用价值。     

IVC anomalies and right renal aplasia detected on CT: a possible link?

Background: We report the occurrence of congenital anomalies of the inferior vena cava (IVC) and right renal aplasia in three patients as detected on computed tomography (CT). Methods: The medical records and imaging studies of three patients with congenital anomalies of the IVC and right renal aplasia were studied. We also reviewed eight reported cases with such an association. Results: Eleven patients, nine adults and two girls, were included in the series. Indications for imaging included deep vein thrombosis (n = 5), hypertension (n = 2), failure to advance a femoral vein catheter cranially (n = 1), dilated veins along the abdominal wall (n = 1), endstage renal failure (n = 1), and jaundice (n = 1). CT was performed in seven patients, and venography, aortography, and other imaging modalities were performed in four. IVC anomalies included partial or complete absence of the IVC in nine patients and a double vena cava in two. The azygos vein was very prominent in all patients in whom the IVC was absent. The right kidney was absent or very small in all patients. Conclusion: The association between IVC anomalies and absence of the right kidney as detected on CT probably was not incidental. Although most patients had symptoms deriving from the anomalies, these might have been clinically silent. The radiologist should be aware of the possible association between these anomalies, which can be detected on CT.     

CT assessment of abdominal hemorrhage in coagulopathic patients: impact on clinical management

Background: To assess how computed tomography (CT) affected clinical management in coagulopathic patients with suspected spontaneous abdominal hemorrhage. Methods: Fifty-four patients with coagulopathy underwent CT for possible abdominal hemorrhage. Medical records were reviewed retrospectively for pre-CT management strategy, degree of clinical suspicion for abdominal hemorrhage, CT findings, and post-CT management strategy. Results: Abdominopelvic CT demonstrated hemorrhage in 31/54 (57%) of patients; 20/54 (37%) of patients had retroperitoneal hemorrhage, 2/54 (4%) had hemoperitoneum, and 9/54 (17%) had hemorrhage confined to the thigh, groin, and/or abdominal wall. CT directly affected clinical management in 28/54 (54%) cases; 17/31 (55%) CT scans that were positive for hemorrhage had a clinical impact versus 11/23 (48%) negative CT scans. This difference was not statistically significant (p= 0.61). CT scans with a higher pretest suspicion for abdominal hemorrhage were more likely to have hemorrhage detected (p= 0.0046) but not more likely to have a clinical impact (p= 0.73). Conclusions: CT to assess for abdominal hemorrhage had a direct impact on clinical management in about one-half of coagulopathic patients. Positive and negative CT studies were equally likely to affect management. Received: 24 February 1998/Accepted: 8 April 1998     

Preoperative assessment of local tumor extent in advanced rectal cancer: CT or high-resolution MRI?

Background: We compared high-resolution magnetic resonance imaging (MRI) with computed tomography (CT) in the assessment of tumor infiltration in surrounding structures for locally advanced primary and recurrent rectal cancer. Methods: Twenty-six patients with operable, locally advanced rectal cancer (15 recurrent and 11 primary) were evaluated with conventional pelvic CT and 1.5-T high-resolution MRI with a quadrature phased-array coil. The images were scored for invasion of nine neighboring pelvic structures, and the results were compared with surgical and histologic findings. Results: A total of 234 structures in 26 patients was evaluated for tumor invasion. For MRI the, sensitivity was 97% and the specificity 98%; for CT, the sensitivity was 70% and the specificity was 85%. The difference in performance was statistically significant (p < 0.001). The failure most frequently made on CT was the false-positive prediction of pelvic floor and piriform muscle invasion (14), whereas MRI showed only four false-positive predictions. MRI correctly predicted all four cases of sacral bone invasion, three of which were missed by CT. MRI was accurate in 20 patients (80%) and CT in only five patients (19%). Conclusion: High-resolution MRI using a quadrature phased-array coil is highly accurate and superior to CT in predicting tumor infiltration in surrounding structures for locally advanced primary or recurrent rectal cancer and is recommended in the preoperative work-up of these tumors. Received: 21 September 1999/Revision accepted: 26 January 2000     

Role of duplex color Doppler ultrasound, computed tomography, and MR angiography in the diagnosis of septic puerperal ovarian vein thrombosis

Background: Septic puerperal ovarian vein thrombosis (SPOVT) is one of the underlying etiologies of puerperal fever. A correct diagnosis of this condition is important because adequate treatment requires additional administration of anticoagulants. The purpose of this study was to evaluate the role of duplex color Doppler ultrasound (CDUS), computed tomography (CT), and magnetic resonance angiography (MRA) in the detection of SPOVT. Methods: Twenty-six patients with puerperal fever suspected to be due to SPOVT and unresponsive to broad antibiotic treatment for at least 48 h were included in a prospective study using CDUS, CT, and MR imaging including MRA. Examinations were analyzed and then correlated to a standard of reference gathered from surgical and clinical follow-up data and from results of imaging. Results: SPOVT was present in nine patients (right side n = 8, bilateral n = 1). CDUS was inconclusive due to gaseous distention of the bowel or obesity in 13 of 26 cases. After counting inconclusive findings as wrong results for statistical purposes, sensitivity, specificity, and accuracy for CDUS were 55.6%, 41.2%, and 46.2%, respectively. CT had a sensitivity of 77.8% with a specificity of 62.5%; accuracy was 68.0%. MRA rendered conclusive results in all evaluated patients, resulting in a sensitivity and specificity of 100%. Conclusion: MRA is recommended in all patients with inconclusive CDUS findings and persistent suspicion for SPOVT. CT has the advantage of more rapid access and lower cost and thus will probably remain a sufficiently accurate alternative. Received 29 July 1997/Accepted 24 September 1997     

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     

Acute hepatic vein occlusion: spiral CT findings in an experimental study

Background: We investigatedspiral computed tomographic (CT) findings and underlying hemodynamic alterations in acute hepatic vein occlusion. Methods: In nine dogs, immediately after balloon occlusion of the right (n = 4) or left (n = 5) hepatic vein through the transjugular or transfemoral route, we performed single-level dynamic CT with intravenous administration of contrast medium. We created time attenuation curves of individual hepatic segments showing attenuation differences. To investigate underlying hemodynamic alterations, hepatic arteriograms were obtained in two dogs. Results: In all cases, there were three compartments with different time attenuation curves: normal, occluded, and adjacent. The normal compartment, which comprised segments far from the occluded hepatic compartment, showed the normal pattern of hepatic enhancement. The occluded compartment, which was the drainage territory of the occluded hepatic vein, showed high attenuation in the early arterial phase and low attenuation in the portal phase. The adjacent compartment, which shared the same portal vein with the occluded compartment and was drained by the patent hepatic vein adjacent to the occluded one, showed strong contrast enhancement in the late arterial and early portal phase. Spiral CT and hepatic arteriography demonstrated the arterioportal shunt and reversed portal venous flow in the occluded compartment, which drained into the adjacent compartment. Conclusion: Acute hepatic vein occlusion on spiral CT appears as mild, early arterial, high attenuation and portal low attenuation of the occluded compartment and strong enhancement in the late arterial and early portal phases of the adjacent compartment due to arterioportal shunt and reversed portal flow. Received: 15 March 2001/Revision accepted: 4 July 2001