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Computed tomographic arterial portography (CTAP) has been shown to be the most sensitive preoperative test for determining resectability of hepatic lesions but we have shown it to have low specificity. Intraoperative ultrasound (IOUS) evaluation of the liver has also been proposed as an accurate means of assessing resectability. We sought to compare the effectiveness of the two modalities. Fifty-six patients who had been deemed candidates for liver resection based on CTAP findings underwent systematic exploration, liver mobilization, and IOUS examination. Ultrasound findings were compared with results of CTAP. In 46 patients the IOUS findings were in complete agreement with those of CTAP. In 10 patients CTAP lesions could not be verified by IOUS and these patients did not undergo resection. Follow-up of these 10 patients revealed eight who did not have progression of malignancy at the CTAP-predicted site (CTAP false positive). Two patients did have progression at a CTAP-positive IOUS-negative site (IOUS false negative). Sensitivity for CTAP and IOUS was 100% and 96%, respectively. Specificity for IOUS was 100%. These findings demonstrate the high sensitivity of CTAP and the high sensitivity and specificity of IOUS. CTAP may "overcall" hepatic lesions but IOUS can correctly identify these false positives in most instances. Because CTAP is useful for determining which patients might benefit from surgical exploration, we conclude that the two modalities are complementary for the assessment of resectability of hepatic lesions. The false positive rate for CTAP implies that caution must be used when declining to operate on patients on the basis of this test.

Purpose: The aim of this study was to compare helical CTAP and helical CT-scan in the preoperative assessment of liver metastases., Methods: A prospective unicentric study in 12 patients was performed with helical CTAP and helical CT-scan. All patients underwent partial hepatectomy with intraoperative palpation and sonography within 19 days (mean: 9 days)., Results: Examination of resected liver specimens found 38 metastases, from colorectal cancer in 36 cases. The sensitivity was 92.1% for helical CTAP and 79% for helical CT-scan. This sensitivity was 85% for helical CTAP and 60% for helical CT-scan for nodules 1 cm or less in diameter (P = 0.08)., Conclusion: In the preoperative screening of liver metastases, helical CT-scan should be performed as the first choice examination. When hepatic lesions seem to be curable by resection based on helical dynamic CT-scan results, helical CTAP should be performed to increase the sensitivity of detection of lesions 1 cm or less in diameter.

Based upon data of 107 angiographic examinations in the regimen of digital subtraction the authors propose a regional program of angiographic examinations of patients with the syndrome of portal hypertension including the digital subtraction recurrent celiac and mesenteric portography, terminal occlusive flebohepatography. The given complex of investigations allows the determination with a minimum traumatic action of the form of portal hypertension and selection of the best for each patient kind of operative intervention. The article describes the methods of angiographic examinations improved and adapted by the authors for diagnosing the syndrome of portal hypertension. Criteria for the assessment of the results obtained are proposed. The use of digital subtraction arterioportography in complex with digital occlusive flebohepatography allows the main problems facing the surgeons when choosing the kind of operative interventions for patients with portal hypertension to be solved.

Purpose: Pseudolesions are sometimes seen around the falciform ligament, around the gallbladder, or at the posterior edge of the medical segment on CT during arterial portography. The purpose of this study was to investigate the influence of liver cirrhosis on these pseudolesions., Method: The basis of this study was 33 patients with liver cirrhosis or hepatitis (group A) and 43 with neither (group B). The standard for diagnosis was surgical findings. We investigated whether there was a difference in the frequency of each pseudolesion between groups A and B. When tumors were seen in each location, they were excluded from statistical analysis., Results: Pseudolesion around the falciform ligament was seen in none of 32 patients in group A and in 18 of 40 in group B (4 cases were excluded), around the gallbladder in 14 of 30 in group A and 16 of 42 in group B (4 cases were excluded), and at the posterior edge of the medial segment in 13 of 33 in group A and 16 of 42 in group B (1 case was excluded). There was a statistically significant difference in the frequency of pseudolesion around the falciform ligament (p < 0.001, Fisher test), but not around the gallbladder or posterior edge of the medial segment., Conclusion: Liver cirrhosis decreases the frequency of pseudolesions around the falciform ligament, but not around the gallbladder or posterior edge of the medial segment.

To evaluate the usefulness of three-dimensional (3D) CT angiography of the portal vein obtained by using a multiple threshold display, 3D reconstructions were performed in 15 patients. The CT scanner employed was the Toshiba Xvigor. A volume of 150 ml of lopamidol 300 mg1/ml was administered at 3.3 ml/sec intravenously. Portal venous phase helical scanning was initiated 80 seconds after the start of the injection. Helical CT data were acquired using up to 25 continuous 1.0-sec rotations during a single breath-hold with an X-ray beam width of 7 mm and a couchtop movement speed of 7 mm/sec. Axial images were reconstructed at a section interval of 3 mm. Both the shaded surface display (SSD) and multiple threshold display (MTD) were generated by using Xtension with Sparc20. MTD was performed as follows. First, voxels, with higher CT values than that of liver parenchyma, were selected. Then, selected voxels were divided into eight parts, which were each assigned gradations of white to grey. The highest part of selected voxels, with higher CT values than that of the second branch of the portal vein, were set to white and a transparency of 0%. The other seven parts were each assigned transparencies of more than 0%. MTD images were compared with SSD in 15 cases by two radiologists. MTD images were superior to SSD images in quality, because MTD diminished surrounding artifacts due to liver parenchyma and enabled small vessels to be depicted clearly. Based on the above results, it was considered that MTD was a useful method for 3D CT angiography using enhanced helical CT.

Purpose: To compare ultrasound (US) to angiography combined with computed tomography during arterial portography (CTAP) in the preoperative evaluation of the portal vein., Materials and Methods: Sixty-three consecutive patients being considered for hepatic resection underwent color and spectral Doppler US and angiography with CTAP before surgery. The main, right, and left portal veins were evaluated separately. A total of 187 veins were assessed for encasement, occlusion, or thrombosis., Results: At surgery, 41 portal veins were abnormal. US allowed detection of 38 of 41 (93%) involved portal veins with 93% sensitivity, 99% specificity, 97% positive predictive value, and 98% negative predictive value. Angiography with CTAP allowed diagnosis of 37 of 41 (90%) involved portal veins with 90% sensitivity, 99% specificity, 95% positive predictive value, and 97% negative predictive value., Conclusion: US is comparable to angiography combined with CTAP in evaluation of the portal vein.

Purpose: To determine the value of spiral CT during arterial portography (SCTAP) in detecting and localising focal liver lesions we compared the SCTAP findings to those gained by conventional CT during arterial portography (CTAP)., Material and Methods: We evaluated a total of CT scans of 128 patients with 162 malignant lesions of the liver. 45 patients underwent SCTAP and 83 patients CTAP. Results of radiological studies were compared with surgical and pathological findings., Results: The overall sensitivity of SCTAP was 93% with a sensitivity of 80% for lesions of less than 1 cm diameter. For CTAP the overall sensitivity was 88%, but the sensitivity for lesions smaller than 1 cm was only 53%. Although with SCTAP examination of hepatic vasculature and liver parenchyma was continuous, we found no advantage in the localisation of lesions to the liver segments compared to CTAP, and the sensitivity of localisation did not correlate with the size of lesions., Conclusion: In our study SCTAP turned out to be a reliable radiological method in the preoperative detection of focal liver lesions, with a high overall sensitivity. SCTAP showed improved sensitivity in the detection of small malignant lesions (< 1 cm) in comparison to CTAP.

Purpose: To prospectively compare the diagnostic accuracy of computed tomography (CT) during arterial portography (CTAP) with that of unenhanced and ferumoxides-enhanced magnetic resonance (MR) imaging at 0.5 T in the detection of hepatic metastases., Materials and Methods: Four pairs of radiologists independently assessed the metastatic involvement of 134 hepatic segments (31 with and 103 without metastasis) in 17 patients at unenhanced and ferumoxides-enhanced spin-echo and gradient-echo MR imaging (alone and in combination) and at CTAP. The diagnostic performance of the various imaging modalities was assessed by means of receiver operating characteristic analysis., Results: The accuracy of CTAP, unenhanced MR imaging (combined unenhanced sequences), and ferumoxides-enhanced MR imaging (combined contrast material-enhanced sequences) was 0.925, 0.908, and 0.951, respectively. Ferumoxides-enhanced MR imaging was significantly more accurate (P < .05) than unenhanced MR imaging and CTAP. When 14 segments containing cysts were excluded, the difference between ferumoxides-enhanced MR imaging and CTAP was no longer statistically significant (P = .1)., Conclusion: Ferumoxides-enhanced MR imaging is more accurate than unenhanced MR imaging and at least as accurate as CTAP for the detection of hepatic metastases.

Spiral computed tomography (CT) performed during arterial portography offers several advantages compared with portographic studies based on conventional CT technique. Because all hepatic images are derived from a volume data set acquired during a single 24-32-second breath hold timed to coincide with the phase of peak hepatic enhancement, motion artifacts and section misregistration are eliminated and high liver-to-lesion attenuation value differences are present on all sections. These factors, in conjunction with the ability to retrospectively acquire thin, overlapping axial sections, result in improved lesion detection. The ability to produce high vein-to-liver attenuation value differences and two-dimensional multiplanar reconstructions simplifies the identification of hepatic segments and therefore lesion localization. A limitation of all CT portographic methods is the frequent occurrence of nontumorous perfusion defects that, in most cases, demonstrate characteristic locations and appearances. Performing delayed CT following portography is one method by which such pseudolesions may be characterized and differentiated from focal pathologic entities.

Purpose: To determine whether the diagnostic quality of computed tomography (CT) during arterial portography (CTAP) performed via the splenic artery (SA) is better than that performed via the superior mesenteric artery (SMA)., Materials and Methods: The authors evaluated CTAP images obtained in 98 patients from 1991 to 1994; 47 examinations were performed via the SA and 51 were performed via the SMA. Images were reviewed, by consensus, by three radiologists blinded to catheter location. Hepatic enhancement was quantitatively assessed in 53 patients (31 in the SA group, 22 in the SMA group)., Results: The numbers of low-attenuation non-tumor-related perfusion defects (19 in the SA group, 17 in the SMA group), high-attenuation non-tumor-related perfusion defects (six in the SA group, six in the SMA group), diffuse mottled perfusion abnormalities (six in the SA group, five in the SMA group), and portal venous flow defects (20 in the SA group, 20 in the SMA group) were similar in both groups (P > .05). Peak hepatic enhancement was similar in both groups (SMA group = 111 HU; SA group = 112 HU) (P > .05)., Conclusion: There is no difference in quality between CTAP performed via the SA versus CTAP performed via the SMA.

Within a period of 12 months we preoperatively performed spiral CT portography (CT-AP) including individual determination of contrast injection kinetics, in 18 consecutive patients. The findings were compared with the microscopic findings in 15 resected specimens. A total of 51 perfusion defects were identified with CT-AP, 40 of which were finally diagnosed as metastases. A total of 36 hepatic lesions were identified at microscopy. 28 of which were metastases, all seen at CT-AP. 12 perfusion defects were misdiagnosed false positive as being of metastatic origin. Thus the sensitivity of CT-AP was 100%, the specificity 65% and the overall accuracy 78%. Therefore, CT-AP using the spiral CT technique is currently the most accurate method for preoperative staging of metastatic disease of the liver. Improvements of the scanning and contrast injection techniques will further improve the clinical value of this examination.

This study was performed to confirm the high sensitivity of CT during arterial portography (CTAP) versus US and dynamic CT in the diagnosis of liver metastases from colorectal cancer. Ninety patients with 108 colorectal cancers underwent US, dynamic CT and CTAP to investigate the presence of liver metastases. US depicted 39 metastases in 26 patients, dynamic CT 46 metastases in 29 patients and CTAP 54 lesions in 34 patients. CTAP detected 8 metastases missed at dynamic CT; 4 of them were < 1 cm in diameter, 3 ranged 1-2 cm and one metastasis > 2 cm in diameter. After preoperative investigations only 7 patients were considered for hepatic resection. At surgery, palpation and intraoperative US of the liver detected two more metastases in the same patients. Our experience, in agreement with recent studies, confirms CTAP as the most sensitive preoperative method in detecting liver metastases and its superiority to be most apparent in lesions < 1 cm in diameter. Therefore, we consider CTAP an essential imaging technique for planning the correct treatment of liver metastases.

We compared two imaging techniques, spiral CT arterial portography (CTAP) and MR imaging, for diagnostic accuracy, procedural cost, and effect on management of 26 patients referred for hepatic surgery for suspected limited malignant liver disease. CTAP and MR imaging were done within a 1-week period (19 within 24 hours); the results of the studies were interpreted prospectively by separate reviewers. Surgical data were evaluated in conjunction with imaging data in 10 patients. Lesion detection and segmental involvement were determined and sensitivity and specificity were calculated. Procedural cost was determined from hospital billing codes. Effect on patient management was determined by the referring oncologic surgeon. CTAP and MR imaging showed 185 and 176 true-positive malignant lesions, 15 and zero false-positive malignant lesions, zero and 18 true-negative malignant lesions, and 13 and 22 false-negative malignant lesions, respectively. CTAP and MR imaging showed 107 and 105 true-positive segments, 11 and zero false-positive segments, 80 and 91 true-negative segments, and four and six false-negative segments, respectively. There was a significant difference in specificity of segmental involvement between MR imaging (1.0 +/- 0) compared with CTAP (0.88 +/- 0.05), P = .03. Total procedural cost was $3,499 for CTAP and $1,224 for MR imaging. CTAP findings did not change patient management over MR imaging findings in any patient, whereas MR imaging findings resulted in a change in patient management over CTAP findings in seven patients (P = .015). The results of our study suggest that MR imaging has higher diagnostic accuracy and greater effect on patient management than CTAP does and is 64% less expensive.

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.

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.

Spontaneous rupture of a pancreatic pseudocyst into the portal vein is described. This has been previously reported in only five cases. Diagnosis was made by computed tomography (CT) and was confirmed by CT-guided transhepatic portography.

Helical (spiral) CT of the liver consistently results in high quality scans as a result of the ability to image the liver in a single breath hold. Lesion detection is aided by scanning during the peak of hepatic enhancement, by the lack of respiratory misregistration, and by obtaining overlapping axial reconstructions. Because of these advantages, helical (spiral) CT is the preferred scanning mode for evaluation of hepatic disease.

The three most common techniques for three-dimensional reconstruction are surface rendering, maximum-intensity projection (MIP), and volume rendering. Surface-rendering algorithms model objects as collections of geometric primitives that are displayed with surface shading. The MIP algorithm renders an image by selecting the voxel with the maximum intensity signal along a line extended from the viewer's eye through the data volume. Volume-rendering algorithms sum the weighted contributions of all voxels along the line. Each technique has advantages and shortcomings that must be considered during selection of one for a specific clinical problem and during interpretation of the resulting images. With surface rendering, sharp-edged, clear three-dimensional reconstruction can be completed on modest computer systems; however, overlapping structures cannot be visualized and artifacts are a problem. MIP is computationally a fast technique, but it does not allow depiction of overlapping structures, and its images are three-dimensionally ambiguous unless depth cues are provided. Both surface rendering and MIP use less than 10% of the image data. In contrast, volume rendering uses nearly all of the data, allows demonstration of overlapping structures, and engenders few artifacts, but it requires substantially more computer power than the other techniques.

Preoperative selection of suitable patients for liver resection is dependent on the quality of radiological imaging. Computed tomography (CT) identifies approximately 70 per cent of lesions. Computed tomographic arterial portography (CTAP) during contrast enhancement of the liver via the portal vein may be superior to conventional CT. Preoperative CTAP was evaluated in 60 patients with hepatic neoplasm (48 having colorectal metastases) who subsequently underwent laparotomy. The preoperative images were compared with intraoperative palpation, intraoperative ultrasonography and histology of the resected liver. Fifty-six patients (93 per cent) underwent partial hepatectomy. The detection rate sensitivity for CTAP was 110 of 116 lesions in the 56 patients (95 per cent) and for intraoperative ultrasonography was 114 of 116 (98 per cent). CTAP correctly identified all lesions found at histology in 50 of 56 (89 per cent) resected specimens. At laparotomy four of 60 patients (7 per cent) were inoperable; two of these had been predicted to be so by this technique. CTAP correctly identifies and locates the majority of hepatic tumours, particularly metastases, and is the procedure of choice for selection of suitable candidates for partial hepatectomy.

Spiral computed tomography during arterial portography (CTAP) combines rapid scanning with selective imaging during the portal phase of enhancement of the liver, resulting in an effective method for evaluation of liver neoplasms prior to partial hepatic resection. Compared with dynamic incremental CTAP, spiral CTAP results in improved quality of three-dimensional and multiplanar reconstructions, facilitating presurgical planning. Accurate volumetric analysis of the tumor can be performed, and subsegmental tumor localization is facilitated by the high levels of hepatic and portal venous enhancement. Additional advantages of spiral CTAP include small reconstruction intervals for improved lesion detection. However, the specificity of spiral CTAP is low because both benign and malignant tumors appear as hypoattenuating perfusion defects. In addition, both focal and geographic nontumorous perfusion defects may be seen more frequently with spiral CTAP than with dynamic CTAP. Knowledge of common diagnostic pitfalls is necessary for accurate interpretation of spiral CTAP images.

Purpose: To compare nicardipine (NCR) and prostaglandin E1 (PGE1) for portal venous contrast enhancement on indirect portography in a retrospective study., Methods: One milligram of NCR, a calcium antagonist, was injected into the superior mesenteric artery just prior to portography in 18 patients who had undergone otherwise identical portography using 20 micrograms PGE1 36-279 (mean 133) days before. All 18 patients had liver tumors and showed no changes in portal vein status in the interim., Results: Using conventional film/screen angiography, NCR provided equally good portograms as PGE1 with respect to image density and image contrast. Systemic effects on blood pressure and heart rate were minimal and no other side effects were observed with NCR., Conclusion: NCR is an inexpensive drug and is expected to provide well-contrasted, indirect portograms on conventional film/screen angiography.

Objective: The purpose of this study was to determine the extent to which reduced portal blood flow in patients with advanced cirrhosis affects contrast enhancement of the liver during CT arterial portography (CTAP). We postulated that reduced and/or irregular hepatic enhancement would limit the efficacy of CTAP for the detection of hepatic tumors in these patients., Materials and Methods: We reviewed the records of 82 patients who had biopsy-proved advanced cirrhosis and who underwent CTAP. Three experienced radiologists evaluated the CTAP studies for adequacy of hepatic parenchymal enhancement. The presence or absence of varices also was documented in an attempt to select a subgroup of patients in whom CTAP showed better hepatic parenchymal enhancement., Results: Forty-seven (57%) of 82 patients had inadequate hepatic parenchymal enhancement to allow an evaluation of the entire liver. Inadequacy was attributable to areas of hyperdense parenchymal enhancement, areas of diffuse nontumoral mottling, or zones of poor parenchymal enhancement (soft-tissue attenuation equal to that of the paraspinal muscle). Parenchymal enhancement was inadequate in 62% of patients with varices and in 28% of patients without demonstrable varices., Conclusion: Our results show that contrast enhancement of the liver during CTAP is altered significantly in patients with cirrhosis. Thus, it is likely that CTAP has limited usefulness for the detection or characterization of hepatic neoplasms in patients with cirrhosis.

Artifacts associated with computed tomographic arterial tomography (CTAP) are well documented. We report a patient undergoing CTAP in whom laminar flow artifact occurred using Iopamidol 370 mg ml-1 but not when using Iopamidol 300 mg ml-1 under identical conditions. The denser Iopamidol 370 mg ml-1 mixed inadequately with unopacified blood in the portal vein. This was not a problem with the less dense Iopamidol 300 mg ml-1 which is likely to be a more reliable contrast agent for CTAP.

Purpose: To determine the optimal scanning parameters for helical computed tomography during arterial portography (CTAP) of the liver., Materials and Methods: Single- and double-helix CTAP were performed in 11 and 20 adult patients, respectively, with 200 mL of contrast material (300 mg of iodine per milliliter) injected at a rate of 3 mL/sec via the superior mesenteric artery. Scanning delays were adjusted for single-helix CTAP so the last scan was obtained at 66 seconds. Delays were adjusted for double-helix CTAP so the last scan during the first helix (CTAP-1) was obtained 10 seconds before the end of the injection at 56 seconds and the first scan during the second helix (CTAP-2) was obtained at the end of the injection at 66 seconds., Results: Single-helix CTAP scans were of poor quality owing to multiple perfusion abnormalities. Lesion detection for double-helix CTAP-1 was 93.2% and was 100% for CTAP-2, and CTAP-2 scans had significantly fewer perfusion abnormalities., Conclusion: A scanning delay of 60-66 seconds appears to be optimal. The CTAP-1 scans showed no useful information and need not be acquired.

Purpose: To evaluate whether computed tomographic arterial portography (CTAP) is best performed with injections in the superior mesenteric artery (SMA) or the splenic artery., Materials and Methods: Seventy-one studies were performed with injection into the SMA (n = 37) or splenic artery (n = 34) of 150 mL of contrast material at 1.5 mL/sec and 20-second delay for both groups. Images were reviewed for location and type of nontumoral perfusion abnormalities. The degree of liver parenchymal enhancement with each technique was compared., Results: Fewer nontumoral perfusion defects were seen with splenic artery (65%) versus SMA (78%) injection. Visual differences in contrast enhancement with greater attenuation in dependent portions of the liver were seen with greater frequency with SMA (41%) than with splenic artery (24%) injection. Contrast enhancement that obscured detail in the right lobe was seen only with SMA injections (16%). Greater parenchymal enhancement (up to 18 HU) at all time intervals was seen with splenic artery injection., Conclusion: Because of greater parenchymal enhancement and fewer nontumoral perfusion abnormalities, splenic artery catheterization is the preferred technique for CTAP.

To attempt to determine the characteristic imaging features of intrahepatic cholangiocarcinoma on spiral CT during arterial portography (CTAP), spiral CTAP examinations of 17 patients with pathologically confirmed intrahepatic cholangiocarcinoma were reviewed in consensus by three radiologists. The diameter of the tumors ranged from 1 to 12 cm (mean diameter, 6.6 cm). All tumors (100%) were hypoattenuating masses on spiral CTAP. In 11 cases, the tumor was homogeneous in attenuation (65%). Tumor margins were smooth and regular in 11 cases (65%). Vascular invasion was found in 14 cases (82%). Intrahepatic bile duct dilatation was present in seven cases (41%). This review shows that intrahepatic cholangiocarcinoma is associated with a constellation of findings on spiral CTAP. The presence of a low attenuation homogeneous intrahepatic mass with vascular invasion and intrahepatic bile duct dilatation on spiral CTAP images should raise the possibility of intrahepatic cholangiocarcinoma. However, these findings can be associated with other types of primary and secondary malignant hepatic tumors.

Magnetic resonance (MR) imaging with arterial portography (MRAP) was compared with computed tomography with arterial portography (CTAP) and conventional MR imaging for preoperative evaluation of hepatic masses in eight patients (nine studies). Twenty contiguous, 10-mm-thick-section CTAP images were obtained. MR imaging included T1- and T2-weighted spin-echo and fast multiplanar SPGR (spoiled gradient-recalled acquisition in the steady state) techniques. For MRAP, 0.1 mmol/kg gadopentetate dimeglumine was injected into the superior mesenteric artery. Portographic-phase, 8-mm-thick-section, axial SPGR images were first obtained, followed by "systemic phase" SPGR images. Lesions were seen best on the portographic-phase MRAP images and were less conspicuous on the systemic-phase MRAP, CTAP and conventional MR images. Of 19 visualized lesions, 18 were seen with MRAP; however; five subcentimeter lesions seen with MRAP were not seen with conventional MR imaging or CTAP. Systemic recirculation of iodinated contrast material from the bolus and from previous angiography is a potential limitation of CTAP. For both CTAP and MRAP, optimal results are expected if all images are obtained during a single breath hold, within seconds of the onset of contrast agent administration.

Two-dimensional time-of-flight (2D-TOF) magnetic resonance (MR) portography tends to produce general image degradation owing to the phase discrepancy caused by multiple breath-holding. To solve this problem, three-dimensional (3D)-MR portographies were reconstructed from image data acquired with a bolus injection of Gd-DTPA with single breath-holding in 20 subjects with normal liver function. 2D-TOF MR portographies were obtained beforehand for the comparison. All the images were displayed in a cine mode for the two MR angiographic techniques. Visualization was assessed as positive when the vessel was visualized without disruption. 3D-MR portography produced a positive rate of over 80% for all but the left first-order branch. With the 2D-TOF techniques, however, only the portal trunk and left second-order branches were visualized at this rate. The positive rate for most portal branches was significantly higher with 3D-MR portography than with the 2D-TOF technique. In conclusion, 3D-MR portography makes it possible to depict the portal venous system without disruption using a short measurement time with single breath-holding and has the potential to become a powerful method for abdominal MR angiography.

Purpose: To determine the sensitivity and false-positive rate of helical computed tomography during arterial portography (CTAP) in the detection of hepatic metastases from colorectal cancer., Materials and Methods: Preoperative helical CTAP was performed to examine 23 patients (10 men and 13 women, aged 43-77 years [mean, 63 years]) who later underwent surgical tumor resection. Imaging findings were retrospectively reviewed by two radiologists and were correlated with intraoperative and histologic findings., Results: Helical CTAP demonstrated 33 of 35 metastases, with diameters of 4-95 mm, that were identified in resected specimens (sensitivity, 94%). The two metastases not demonstrated were 4 and 5 mm in diameter. Five false-positive lesions were found in four patients, yielding a false-positive rate of 17% by patient analysis and 13% by lesion analysis., Conclusion: The sensitivity of helical CTAP in the preoperative detection of hepatic metastases is high, and its false-positive rate compares favorably with that of conventional CTAP, but future comparative studies are needed to determine which is the better modality.

Purpose: To evaluate portal blood flow in small hepatocellular carcinomas (HCCs) by means of computed tomography during arterial portography (CTAP) and CTAP with hepatic arterial obstruction (CTP-HAO) achieved by means of balloon occlusion., Materials and Methods: Thirteen patients with small HCC (< 20 mm in diameter) underwent CTAP, CTP-HAO, carbon dioxide-enhanced ultrasound (CEUS), and digital subtraction angiography (DSA). The imaging findings were correlated with histologic features., Results: The first group of patients (n = 3) had tumors with portal blood flow at both CTAP and CTP-HAO and no hypervascularity at CEUS. The second group (n = 3) had tumors with portal blood flow at CTP-HAO but not at CTAP and hypervascularity at CEUS only. The third group (n = 7) had tumors without portal blood flow at CTAP or CTP-HAO and hypervascularity at DSA and CEUS. The first and second groups had well-differentiated HCCs; six of seven patients in the third group had moderately differentiated HCCs., Conclusion: Lack of portal blood flow was reversible in well-differentiated HCCs but irreversible in the other tumors.

Purpose: To analyze the correlation between pseudolesions seen in segment IV of the liver and aberrant gastric venous drainage (AGVD)., Materials and Methods: Twenty-two patients with a pseudolesion in the posterior edge of segment IV of the liver (group A) and 100 randomly selected patients without pseudolesions (group B) underwent computed tomography during arterial portography (CTAP) and hepatic arteriography. The frequency of the visualization of AGVD to segment IV was compared for groups A and B., Results: AGVD was seen at arteriography in 18 of 22 patients in group A. None of the patients in group B had AGVD. The difference in the frequency of angiographically visible AGVD was statistically significant (chi 2 test, P < .01)., Conclusion: AGVD is the main cause of pseudolesions in the posterior edge of segment IV of the liver.

Objective: Nontumorous perfusion defects occur during CT arterial portography (CTAP) as normal variants or in cirrhosis, focal fatty infiltration, and portal vein obstruction. The purpose of this study was to determine whether delayed CT 4-6 hr after CTAP improves sensitivity to hepatic tumors and differentiates them from other hepatic perfusion defects., Subjects and Methods: CTAP was done at 1-cm increments on 26 patients for evaluation of hepatic tumors. Delayed CT scans were obtained 4-6 hr later in all patients. Two observers retrospectively reviewed the CT scans obtained during CTAP and recorded size, shape, and location of suspected hepatic tumors. Confidence levels were assigned for each tumor. The delayed CT scan was then interpreted in conjunction with the CT scans obtained during CTAP, and confidence levels were reassigned. Surgical correlation was obtained for all patients. In the 26 patients, 86 masses were found at surgery. The sensitivity and number of false-positives for both CTAP alone and CTAP combined with delayed CT were compared with a two-tailed Student t-test. Receiver-operating-characteristic analysis also was performed., Results: CTAP detected 73 (85%) of the 86 hepatic masses. Delayed CT had no effect on the sensitivity of CTAP. However, adding delayed CT decreased the total number of false-positives by 11, a statistically significant difference (p < .05). Receiver-operating-characteristic analysis revealed a significantly greater (p < .05) area under the curve (Az index) of 0.927 +/- 0.025 for CTAP combined with delayed CT compared with 0.886 +/- 0.032 for CTAP alone. Delayed CT was most useful for larger (> 1 cm) wedge-shaped perfusion defects and least useful for smaller (< 1 cm) round defects., Conclusion: Delayed CT has no effect in detecting tumors but may be useful for differentiating tumors from other hepatic perfusion defects seen on CTAP. The greatest benefit of delayed CT is in evaluating regions obscured by large wedge-shaped perfusion defects on CT scans obtained during CTAP.

Purpose: To evaluate the efficacy and complications of transportal ethanol injection (TPEI) combined with transcatheter arterial chemoembolization to achieve complete tumor necrosis and prevent intrahepatic metastases in patients with hepatocellular carcinoma (HCC)., Materials and Methods: In 13 patients with HCC, chemoembolization was performed with injection of a mixture of iodized oil and doxorubicin hydrochloride followed by administration of gelatin sponge; 1-4 weeks later, TPEI was performed with percutaneous transhepatic portography. Ethanol (15-65 mL) was injected in the portal veins around the tumor until occlusion., Results: TPEI was successfully performed in all patients. Two patients subsequently underwent surgery; their tumors were resected completely. Two died of hepatic failure. Seven of the nine other patients showed no recurrence or intrahepatic metastasis during follow-up (7-42 months). Histologic examination, performed in nine patients, showed complete necrosis of tumor and scattered or severe necrosis of surrounding tissues., Conclusion: This treatment has a strong anticancerous effect and is expected to be used in treatment of properly selected patients with HCC.

The use of combined invasive nuclear medicine procedures allows the estimation of intra- and extrahepatic shunt volumes in patients with liver cirrhosis. The investigations were carried out after transhepatic portography and injection of 99mTc-MAA into the peripheral portal vein (hilum of the spleen) as well as into the central portal vein (hilum of the liver). A subtraction technique allowed the evaluation of shunt volumes (percentage). In 32 out of 36 patients an extra-hepatic shunt volume of 29.2% (0%-84%) and an intra-hepatic shunt volume of 23.6% (0%-81%) was found. This technique may contribute to improving the results of shunt surgery.

A major role of imaging in the evaluation of hepatic tumors is to assist surgeons in the preoperative determination of the feasibility of hepatic resection. Although the segmental location of tumors is not the sole criterion for determining resectability, such knowledge is useful for preoperative planning of the type of resection. This essay illustrates the surgical segmental and subsegmental anatomy of the liver as shown by spiral CT during arterial portography (CTAP) with multiplanar reformation.

Objective: We did a retrospective study to evaluate the sensitivity of CT combined with arterial portography in detecting recurrent hepatic metastases after partial hepatectomy., Materials and Methods: CT scans combined with arterial portography in 18 patients who had partial hepatectomy and suspected intrahepatic recurrence of metastases were retrospectively reviewed. Eleven of the patients had further surgery, and recurrent hepatic metastases were proved; seven patients were inoperable. The sensitivity of CT with arterial portography for detecting recurrent intrahepatic metastases was determined and correlated with intraoperative findings and findings on follow-up imaging studies in the 11 patients (with a total of 23 hepatic metastases) who had further surgery., Results: Not one of the 18 CT examinations combined with arterial portography was compromised by inhomogeneous perfusion of contrast material in the portal vein. Of the 23 metastases that were found in the 11 patients who had further surgery, 21 (91%) were shown on CT with arterial portography. In two patients, CT with arterial portography showed two subcapsular hypoattenuating pseudolesions that were correctly identified as nontumorous perfusion defects, as confirmed by intraoperative findings and follow-up imaging studies., Conclusion: This study shows that postoperative CT with arterial portography is efficacious in the detection of intrahepatic recurrent metastases in patients who have had a partial hepatectomy. Furthermore, prior partial hepatectomy does not compromise the quality of this examination.

Serial computed tomography during arterial portography (CTP) and CT during arteriography (CTA) of the liver could be performed on nine of ten patients with hepatocellular carcinoma, using triple-lumen balloon catheters (3-B-C). The 3-B-C was inserted into the common hepatic artery, and the balloon was inflated. We have injected contrast medium into the splenic artery through the side hole of the 3-B-C to perform CTP, and then into the common hepatic artery through the tip hole to perform CTA.

CT portography is the most sensitive technique currently available for the preoperative diagnosis of liver metastases. We report on a patient with liver steatosis in whom ultrasound examination revealed two liver metastases in the follow up after resection of a papillary carcinoma. The liver metastases could be clearly identified both on plain CT and on enhanced CT with dynamic bolus contrast medium injection. Because of the small difference in attenuation values between liver parenchyma and metastases the two liver metastases had not been recognized on CT portography. When severe and diffuse liver steatosis is present CT portography may fail to detect metastases or small hepatocellular carcinoma.

Various imaging modalities currently used to evaluate liver tumors include magnetic resonance imaging, ultrasonography, contrast-enhanced computed tomography, and computed tomographic arterial portography. In our review of 28 cases, we found CT arterial portography to be very sensitive, and in 5 of these 28 cases CT arterial portography was a key factor in altering the course of therapy.

The diagnosis of liver tumors should be utilized for determination of not only the number of lesions, but also their size, segmental location and extent, and the relationship of the mass or masses to the hepatic vasculature. CT during arterial portography (CTAP) is the most sensitive imaging modality for precise diagnosis of hepatocellular carcinoma. CTAP is thus widely used as a diagnostic imaging technique, particularly for the detection of small hepatocellular carcinomas. Conventional splenic portography has been carried out for many years using a wide diameter needle, a large amount of contrast medium and a film-screen system. Since the development of arterial portography, fewer splenoportograms have been performed due to the high incidence of bleeding and other complications. In this study a 0.6-mm (23 gauge) thin needle was used for splenic puncture and CT was used as a detector instead of a film-screen system. With this technique CT during percutaneous transsplenic portography may be performed on an outpatient basis.

The Warren-Zeppa selective distal spleno-renal shunt is aimed at decompressing esophageal varices while at the same time ligating left gastric, gastroepiploic and umbilical veins. But in the long term follow-up loss of shunt selectivity was observed in a number of cases (7/76), with hepatic encephalopathy resulting in 9.3%. In this study, we carried out percutaneous transhepatic portography and investigated pancreatic hormone kinetics in portal blood after arginine load, mainly in cases of hepatic encephalopathy after distal splenorenal shunt compared with non-encephalopathy cases of LC + Varix. These data suggested that as a cause of encephalopathy after distal splenorenal shunt, (1) a marked decrease in portal blood flow due to portal systemic shunt via the pancreatic vein was considered from PTP image, (2) a marked decrease in I/G ratio was considered from pancreatic hormone kinetics in portal blood.

Preoperative imaging in patients with potentially resectable liver tumours has traditionally been performed in specialized hepatobiliary centres. To assess the feasibility and value of establishing a same-day, pre-resectional hepatic imaging service, computed tomography during arterial portography (CTAP) and delayed high-dose iodine computed tomography (DICT) were used to examine patients considered suitable for curative hepatic resection. The study group comprised 27 patients (14 from hospitals not affiliated with a university and 13 from two university-affiliated hospitals) for whom pre-referral imaging showed tumour distribution amenable to resection. Among the patients from centres not affiliated with a university, seven had undergone ultrasonography (US) and equilibrium-phase CT, four had undergone US and unenhanced CT, two had undergone equilibrium-phase CT only and one had undergone bolus dynamic incremented CT (BDCT) only. For 12 of the patients coming from the university-affiliated centres, the pre-referral imaging had consisted of US and BDCT; the other had undergone US only. After CTAP and DICT, 20 (74%) of the 27 patients were reclassified as having unresectable disease: 7 (54%) of the 13 patients who had undergone BDCT before CTAP and DICT and 12 (92%) of the 13 patients who had undergone unenhanced or equilibrium-phase CT, as well as the patient who had undergone US only. By averting laparotomy in 20 of the patients, CTAP and DICT resulted in short-term health care savings of about $160,000. These findings suggest that BDCT was underused in the hospitals not affiliated with university centres.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: The purpose of this study was to determine the effect of precontrast injection of papaverine hydrochloride into the superior mesenteric artery on the degree of contrast enhancement of the hepatic parenchyma during CT arterial portography (CTAP, CT with injection of contrast material into the superior mesenteric artery)., Subjects and Methods: Twenty-two patients were included in this study. All patients had a baseline unenhanced CT scan and then had CTAP performed with transcatheter injection of 150 ml of nonionic iodinated contrast material (30 g iodine/100 ml) at a rate of 2 ml/sec. Eleven patients received a precontrast injection of 40 mg of papaverine hydrochloride via catheter into the superior mesenteric artery, and 11 patients had CTAP without papaverine hydrochloride. Attenuation of the liver was measured before and after contrast administration in both groups of patients. For each CTAP section, the absolute hepatic enhancement (postcontrast attenuation--precontrast attenuation) and the relative hepatic enhancement ([absolute hepatic enhancement/precontrast attenuation] x 100) were calculated. Also, the mean absolute enhancement and the mean relative enhancement for the entire liver were calculated for each patient., Results: The mean relative enhancement (+/- SD) of hepatic parenchyma was 192 +/- 54% with papaverine hydrochloride and 146 +/- 26% without papaverine hydrochloride. Relative enhancement was significantly higher when papaverine hydrochloride was used (p < .02). The mean absolute enhancement (+/- SD) of hepatic parenchyma was 123 +/- 25 H with papaverine hydrochloride and 91 +/- 19 H without papaverine hydrochloride. Absolute enhancement was significantly higher in patients who had papaverine hydrochloride (p < .01)., Conclusion: The results show that precontrast transcatheter infusion of papaverine hydrochloride increases the degree of contrast enhancement of the liver during CTAP.

CT arterioportography using indirect portal venous application of contrast media is the most sensitive preoperative diagnostic technique for detection of liver metastases. Spiral CT allows continuous examination of the liver (no gap) during a single breathhold. Due to short measurement times an optimized vessel and tissue contrast can be achieved during the portal venous phase. Compared with intraoperative ultrasonography CTAP using spiral CT offers similar sensitivity (96%) in the detection of liver metastases and thus emerges as an important technique for diagnosis and follow-up of liver metastases.

Intra-arterial digital subtraction portography (IA-DSP) with a blood-isotonic, non-ionic, dimeric contrast medium was carried out in 27 patients with hepatocellular carcinoma. It was possible to obtain images of excellent or good quality of the portal vein and its bilateral main branches in all patients. The third-order branches of the portal vein in the right lobe could be identified in all patients, and images of excellent or good quality were obtained in a mean of 80.2% of patients. Images of third-order branches in the left lobe were of lower quality than those of third-order branches in the right lobe; in particular, images obtained were of poor quality for 27.3% of the medial branches of the left lobe. It was impossible to identify the caudal branches in almost all patients. The side effects of IA-DSP, pain and sensations of heat were very mild: only one patient complained of mild pain, while 18 patients (69.2%) complained of no sensations of heat whatsoever.

To evaluate the accuracy of CT arterial portography (CTAP) of the liver, CTAP examinations from 111 patients were retrospectively reviewed and compared with the findings at laparotomy. Laparotomy had been performed within 3 weeks after the CTAP examination. In cases of resectable liver tumor, the result from the pathologic examination report was used to calculate the accuracy of CTAP. In cases of nonresectable liver tumor or liver without tumor, CTAP findings were compared with the result of a thorough inspection and palpation of the liver. The right liver lobe and the medial and lateral segments of the left lobe were separately evaluated. Thus, a total of 333 lobes/segments were evaluated. Tumor was found at laparotomy in 80 of 333 lobes or segments. At CTAP a total of 94 lobes were evaluated as positive for tumor growth, 23 of these were falsely interpreted as positive and 9 were falsely interpreted as negative when compared with the findings at laparotomy. However, 3 patients called false-positives later turned out to be true-positives since the lesions were overlooked at operation. A sensitivity of 89%, a specificity of 91%, and an accuracy of 90% was calculated for CTAP. It is concluded that CTAP has a higher accuracy than other radiologic methods and should be considered suitable for preoperative evaluation of potentially resectable liver tumor.