Hepatic parenchymal perfusion defects detected with CTAP: imaging-pathologic correlation

Pseudolesions on clinical imaging caused by Sappey veins: a dynamic contrast magnetic resonance and Doppler study

AIM

This study aimed to investigate the anatomy and mechanism of pseudolesions around falciform ligament, which appeared on dynamic contrast magnetic resonance (MR) imaging.

METHODS

A total of 30 cases were included in the normal control group (group 1), and 30 cases were enrolled into the liver cirrhosis group (group 2). All cases underwent MR examination including in-phase and out-phase T1-weighted image, T2-weighted fat-suppressed image, and dynamic MR imaging enhancement scanning. The MR images were analyzed to detect pseudolesions, and results from the 2 groups were compared. An ultrasound examination was also performed in all cases to assess the abdominal umbilical vein blood flow.

RESULTS

In group 1, MR images detected pseudolesions in 13 cases, and signal reduction did not appear in out-phase MR images compared with in-phase MR images. In 5 of these cases, the umbilical vein was observed to be connected with the hepatic IV segment, and direction flow was toward hepatic during Doppler ultrasound examination. In the 30 patients with liver cirrhosis, pseudolesions were not detected in any of the cases, dilation of the vena epigastricas was observed in 12 cases, and flow direction was from liver. The difference in the incidence of falciform ligament pseudolesions between group 1 and group 2 was statistically significant (P > 0.01).

CONCLUSIONS

Pseudolesions around the falciform ligament are associated with the Sappey vein, and there is no significant relationship with fatty infiltration.

Utility of adding Primovist magnetic resonance imaging to analysis of hepatocellular carcinoma by liver dynamic computed tomography

BACKGROUND & AIMS

More information is needed on use of Primovist-enhanced magnetic resonance imaging (MRI) during initial staging analysis of patients with hepatocellular carcinoma (HCC) who are candidates for treatment with liver dynamic computed tomography (CT).

METHODS

We studied 104 patients who were initially diagnosed as Barcelona Clinic Liver Cancer (BCLC) stage 0 or A, without any other suspicious intrahepatic lesions, by liver dynamic CT from December 2009 to May 2012 at Inha University Hospital in Korea. We evaluated whether an addition of Primovist-enhanced MRI examination affected determination of BCLC stage, compared with liver dynamic CT.

RESULTS

On the basis of CT analysis, the median tumor size was 2.3 cm, and 98 patients had HCCs that met the Milan criteria (94.2%). All 104 patients (100%) had nodular type HCC. Abnormal intrahepatic findings were detected by Primovist-enhanced MRI in 41 patients (39.4%). Eighteen patients (17.3%) had new HCCs, but 6 patients who were initially of BCLC stage A remained at this stage, despite increases in tumor numbers. Of the 104 patients, 31 (29.8%) and 73 (70.2%) had BCLC stage 0 and A HCC before Primovist-enhanced MRI, respectively, and 26 (25.0%), 71 (68.3%), and 7 (6.7%) patients had BCLC stages 0, A, and B HCC after Primovist-enhanced MRI, respectively. In 12 of the 104 patients (11.5%), BCLC stage changed from 0 to A (5/31, 16.1%) or from A to B (7/73, 9.6%).

CONCLUSIONS

Primovist-enhanced MRI can provide additional information that can lead to the detection of new intrahepatic HCC lesions during initial staging analyses of patients with BCLC stage 0 or A HCC by liver dynamic CT, despite the absence of other suspicious liver lesions.

Confident non-invasive diagnosis of pseudolesions of the liver using diffusion-weighted imaging at 3T MRI

PURPOSE

Pseudolesions of the liver including focal steatosis or non-steatosis and THID (transient hepatic intensity differences) are often challenging, especially when imaging patients with underlying malignant disease. We evaluated the efficacy of diffusion-weighted imaging (DWI) in the diagnostic work-up of pseudolesions.

MATERIALS AND METHODS

Forty-eight patients with pseudolesions of the liver were consecutively examined and the images were retrospectively analyzed. MRI was performed on a clinical 3T scanner using T1-GRE in-phase and opposed phase images, T2-TSE-FS, diffusion-weighted sequences (b-value 50, 300, 600), ADC mapping, and dynamic post-contrast T1-VIBE-FS sequences (32 patients received Gd-EB-DTPA and 16 patients received gadolinium chelates). All images were analyzed by two experienced radiologists in consensus. As a standard of reference, we used the T1-w GRE, in-phase and out of phase, and the contrast enhanced series, as well as long-term follow-up.

RESULTS

In the 48 patients, a total of 116 liver lesions were found. Of these, 40 were benign and eleven were malignant focal lesions. Benign lesions included one FNH, 26 simple cysts, and twelve hemangiomas. In addition, 65 pseudolesions (20 focal steatosis, 13 focal non-steatosis, and 32 THIDs) were found. All pseudolesions could be identified either on the T1-GRE in-phase and opposed phase images or on the contrast-enhanced series, or on both. However, none of them were visible on the diffusion-weighted images.

CONCLUSION

Pseudolesions are invisible on DWI (negative predictive value = 1); therefore, DWI can be used as an additional sequence to significantly increase diagnostic confidence in the differentiation between pseudolesions and other focal liver lesions.

Success of image-guided biopsy for small (≤ 3 cm) focal liver lesions in cirrhotic and noncirrhotic individuals

PURPOSE

Imaging techniques can detect small liver lesions, although these are a challenge to biopsy, particularly in cirrhotic liver. The authors assessed the diagnostic success of image-guided biopsies collected from small (≤ 3 cm) focal liver lesions.

MATERIALS AND METHODS

This single-center, retrospective study included 374 patients (199 men; mean age, 62 ± 15). Eighteen-gauge core biopsy and 22-gauge fine needle aspiration (FNA) samples were collected from small focal liver lesions. Samples were compared by histology versus cytology, malignant versus benign, from lesions smaller versus larger than 1.5 cm, from livers with versus without cirrhosis, collected by computed tomography (CT) guidance versus ultrasound, and from different locations in the liver.

RESULTS

The combined accuracy of core biopsy plus FNA analysis was 95.5%; core biopsy alone characterized 93.3% of samples, and FNA alone characterized 72.5% (P < .001). Biopsy successfully characterized 94.5% of malignant lesions and 98.8% of benign lesions (P > .05). Biopsy characterized 95.3% (102 of 107) lesions ≤ 1.5 cm. The success in cirrhotic livers was 94.8%, for CT-guided biopsies was 95%, and for ultrasound-guided biopsies was 95.8% (P > .05). The success rate was lower in liver caudate lobe than in other locations (P < .05).

CONCLUSIONS

Image-guided biopsy of small (≤ 3 cm) focal liver lesions is highly reliable with the use of core biopsy alone. Neither size ≤ 1.5 cm nor presence of cirrhosis is an impediment to biopsy. CT and ultrasound guidance produce similar rates of success.

The usefulness of three-dimensional angiography with a flat panel detector of direct conversion type in a transcatheter arterial chemoembolization procedure for hepatocellular carcinoma: initial experience

The purpose of this study was to assess the usefulness of a three-dimensional (3D) angiography system using a flat panel detector of direct conversion type in treatments with subsegmental transcatheter arterial chemoembolization (TACE) for hepatocellular carcinomas (HCCs). Thirty-six consecutive patients who underwent hepatic angiography were prospectively examined. First, two radiologists evaluated the degree of visualization of the peripheral branches of the hepatic arteries on 3D digital subtraction angiography (DSA). Then the radiologists evaluated the visualization of tumor staining and feeding arteries in 25 patients (30 HCCs) who underwent subsegmental TACE. The two radiologists who performed the TACE assessed whether the additional information provided by 3D DSA was useful for treatments. In 34 (94.4%) of 36 patients, the subsegmental branches of the hepatic arteries were sufficiently visualized. The feeding arteries of HCCs were sufficiently visualized in 28 (93%) of 30 HCCs, whereas tumor stains were sufficiently visualized in 18 (60%). Maximum intensity projection images were significantly superior to volume recording images for visualization of the tumor staining and feeding arteries of HCCs. In 27 (90%) of 30 HCCs, 3D DSA provided additional useful information for subsegmental TACE. The high-quality 3D DSA with flat panel detector angiography system provided a precise vascular road map, which was useful for performing subsegmental TACE of HCCs.

Prospective, blinded comparison of helical CT and CT arterial portography in the assessment of hepatic metastasis from colorectal carcinoma

OBJECTIVE

This prospective blinded comparison of helical CT and helical CT arterial portography aimed to detect liver metastasis from colorectal carcinoma.

METHODS AND MATERIALS

50 patients with colorectal carcinoma were evaluated comparing helical CT with helical CT arterial portography. Each imaging study was evaluated on a 5-point ROC scale by radiologists blinded to the other imaging findings, and the results were compared, with the surgical and pathologic findings as the gold standard.

RESULTS

Of the 127 lesions found at pathology identified as metastatic colorectal cancer, helical CT correctly identified 85 (69%) and CT portography 96 (76%). When subgroups with lesions <3 cm (48 patients) and patients with maximum tumor size <3 cm (18 patients) were considered, CT portography was always better than helical CT in terms of sensitivity, specificity, positive predictive value, and negative predictive value. ROC analysis adjusting for multiple lesions per patient revealed significantly greater area under the curve (AUC) for the subgroup of lesions <3 cm (CT-AUC of 77% and CT portography AUC of 81%; P = 0.002).

CONCLUSIONS

For identification of large metastases, helical CT and CT portography have similar yield. However, for detection of small liver metastases, CT portography remains superior for lesion detectability.

PET imaging for evaluation of metastatic colorectal cancer of the liver

Colorectal cancer is a major cause of cancer death in Western Europe and United States; the liver is the most common site for colorectal metastases. PET has an important role in the management of patients with colorectal liver metastases. It is an effective tool to detect hepatic metastases and to monitor the response to systemic and local therapy. The major impact of PET-CT over PET alone is the improvement in the certainty of lesion location. PET-CT has the unique advantage to combine functional and anatomic imaging in an integrated scanner; it allows a thoroughly evaluation of patients with colorectal liver metastases.

PET and PET-CT for evaluation of colorectal carcinoma

The evaluation of patients with known or suspected recurrent colorectal carcinoma is now an accepted indication for positron emission tomography using (18)F-fluorodeoxyglucose (FDG-PET) imaging. FDG-PET does not replace imaging modalities such as computed tomography (CT) for preoperative anatomic evaluation but is indicated as the initial test for diagnosis and staging of recurrence and for preoperative staging (N and M) of known recurrence that is considered to be resectable. FDG-PET imaging is valuable for the differentiation of posttreatment changes from recurrent tumor, differentiation of benign from malignant lesions (indeterminate lymph nodes, hepatic and pulmonary lesions), and the evaluation of patients with rising tumor markers in the absence of a known source. The addition of FDG-PET to the evaluation of these patients reduces overall treatment costs by accurately identifying patients who will and will not benefit from surgical procedures. Although initial staging at the time of diagnosis is often performed during colectomy, FDG-PET imaging is recommended for a subgroup of patients at high risk (with elevated CEA levels) and normal CT and for whom surgery can be avoided if FDG-PET shows metastases. Screening for recurrence in patients at high risk has also been advocated. FDG-PET imaging seems promising for monitoring patient response to therapy but larger studies are necessary. The diagnostic implications of integrated PET-CT imaging include improved detection of lesions on both the CT and FDG-PET images, better differentiation of physiologic from pathologic foci of metabolism, and better localization of the pathologic foci. This new powerful technology provides more accurate interpretation of both CT and FDG-PET images and therefore more optimal patient care. PET-CT fusion images affect the clinical management by guiding further procedures (biopsy, surgery, radiation therapy), excluding the need for additional procedures, and changing both inter- and intramodality therapy.

Lower prevalence of non-tumoral perfusion defects in left hepatic lobe during CT arterial portography with splenic artery injection

OBJECTIVE

To determine whether there is a difference in the prevalence of non-tumoral perfusion defects (NTPD) in left hepatic lobe during CT arterial portography (CTAP) through splenic (SA) and superior mesenteric artery (SMA) injection.

METHODS AND PATIENTS

For the preoperative evaluation, 59 patients (20 females, 39 males) who either have colorectal carcinoma metastasis (n: 42) or hepatocellular carcinoma (n: 17) underwent CTAP examination. Patients were divided into two groups (SA and SMA) according to the injection artery. The presence and type of NTPD in the left hepatic lobe were determined and compared.

RESULTS

There were significant differences in peripherally located wedge shaped, perihilar-periligamentous and pericholecystic NTPD, but no significant difference was found in lobar/segmental defects between the groups.

CONCLUSIONS

Our study demonstrated lower prevalence of NTPD in the left hepatic lobe in CTAPs performed through SA injection and we think that this could be explained by the streamlining of portal blood flow.

Detection of colorectal liver metastases: a prospective multicenter trial comparing unenhanced MRI, MnDPDP-enhanced MRI, and spiral CT

The aim of this study was to compare unenhanced MRI, MnDPDP-enhanced MRI, and spiral CT in the detection of hepatic colorectal metastases. Forty-four patients with hepatic colorectal metastases were examined with unenhanced and MnDPDP-enhanced MRI and with unenhanced and contrast-enhanced spiral CT. The MR examination protocol included baseline T1-weighted spin-echo (SE), T1-weighted gradient-recalled-echo (GRE), and T2-weighted fast-SE sequences; and T1-weighted SE and T1-weighted GRE sequences obtained 30-60 min after administration of 0.5 micromol/kg (0.5 ml/kg) mangafodipir trisodium (MnDPDP). Images were interpreted by three blinded readers. Findings at CT and MRI were compared with those at intraoperative US, which were used as term of reference. Intraoperative US detected 128 metastases. In a lesion-by-lesion analysis, the overall detection rate was 71% (91 of 128) for spiral CT, 72% (92 of 128) for unenhanced MRI, and 90% (115 of 128) for MnDPDP-enhanced MRI. MnDPDP-enhanced MRI was more sensitive than either unenhanced MRI ( p<0.0001) or spiral CT ( p=0.0007). In a patient-by-patient analysis, agreement with gold standard was higher for MnDPDP-enhanced MRI (33 of 44 cases) than for spiral CT (22 of 44 cases, p=0.0023) and unenhanced MRI (21 of 44 cases, p=0.0013). MnDPDP-enhanced MRI is superior to unenhanced MRI and spiral CT in the detection of hepatic colorectal metastases.

Effect of prostaglandin E1 on contrast enhanced CT of the liver: statistical analysis during arterial portography

PURPOSE

To determine the diagnostic effect of prostaglandin E(1) on contrast enhancement quality of CT during arterial portography (CTAP).

MATERIALS AND METHODS

Our patients population included 30 patients (11 women, 19 men; age range, 41 approximately 81 years) with liver tumors (23 hepatocellular carcinoma and 7 metastatic liver tumor) who had undergone angiography. We divided the 30 patients, who had undertaken CTAP twice, into two groups at random (group A; n=15, group B; n=15). In group A, first CTAP was performed without prostaglandin E(1). Approximately 5 minutes later, a second CTAP was again initiated 30 seconds after injection of prostaglandin E(1) under the same conditions. In group B, prostaglandin E(1) was injected before the first CTAP only. We measured the mean CT numbers and standard deviation (SD) numbers of anterior, posterior, medial and lateral segments in the liver at the same section of the CTAP using the same size and location of the regions of interest, and these values with and without prostaglandin E(1) were compared.

RESULTS

1) CT numbers: The CT numbers were significantly increased in the medial segment after the injection of prostaglandin E(1) (p<0.05) in all cases of both groups. On the other hand, they were clearly decreased in the posterior segment after the injection of prostaglandin E(1) (p<0.05) in both groups. There were no statistical differences in the CT numbers in the anterior and lateral segments in all patients. In addition, the CT numbers of anterior and posterior segments showed high attenuation compared with the medial and lateral segments in group A without prostaglandin E(1). 2) SD numbers: The SD numbers, which are an index of the homogeneous enhancement, were significantly decreased in the posterior, medial and lateral segments after the injection of prostaglandin E(1) (p<0.01, p<0.05, p<0.01, respectively) in both groups. There were no significant differences in the SD numbers in the anterior segment regardless of the injection of prostaglandin E(1) in all cases.

CONCLUSION

CTAP with injection of prostaglandin E(1) makes contrast enhancement of liver parenchyma more homogeneously than the conventional procedure, and it may be a useful technique for the detection of liver tumors.

Pretransplantation evaluation of the cirrhotic liver with explantation correlation: accuracy of CT arterioportography and digital subtraction hepatic angiography in revealing hepatocellular carcinoma

OBJECTIVE

The aim of this study was to determine the accuracy of CT arterioportography and hepatic digital subtraction angiography, separately and combined, for the detection of hepatocellular carcinoma in the cirrhotic liver by using thin-section liver explant histopathologic findings.

SUBJECTS AND METHODS

Fifty-nine patients with liver cirrhosis were examined with CT arterioportography and digital subtraction angiography as a part of preoperative diagnostic workup for liver transplantation. Before liver explantation, CT arterioportograms and digital subtraction angiograms were prospectively evaluated in a blinded manner, separately by two CT radiologists and two angiographers, respectively, and combined by two reviewer teams, each including a CT radiologist and an angiographer. In addition, each examination was retrospectively evaluated using direct comparison with the corresponding thin-section liver explant specimens

RESULTS

There were 39 histologically confirmed hepatocellular carcinomas. In both prospective and retrospective assessments, the reviewers achieved the best performance with CT arterioportography and digital subtraction angiography combined (area under the curve [A(z)] 0.82). The diagnostic confidence in the detection of hepatocellular carcinoma was higher with digital subtraction angiography (A(z), 0.81) than that with CT arterioportography (A(z), 0.68). Prospectively, sensitivity and specificity were 75% and 60% for CT arterioportography, 77% and 80% for digital subtraction angiography, and 84% and 81% for CT arterioportography and digital subtraction angiography combined, respectively. Retrospectively, sensitivity and specificity were 80% and 62% for CT arterioportography; 82% and 79% for digital subtraction angiography; 87% and 81% for CT arterioportography and digital subtraction angiography combined, respectively. Five hepatocellular carcinomas, one poorly and four well differentiated, with a mean size of 1.4 cm were not detectable on the CT arterioportography and digital subtraction angiography combination. False-positive findings were 20, 11, and 10 on CT arterioportography, digital subtraction angiography, and the CT arterioportography and digital subtraction angiography combination.

CONCLUSION

Combining CT arterioportography with digital subtraction angiography enabled reliable detectability of moderately and poorly differentiated hepatocellular carcinomas in cirrhotic livers but was less sensitive for the detection of well-differentiated hepatocellular carcinomas and resulted in a relatively high rate of false-positive findings.

Preoperative evaluation of hepatocellular carcinoma: combined use of CT with arterial portography and hepatic arteriography

OBJECTIVE

This study was undertaken to determine the usefulness of combined CT during arterial portography and CT hepatic arteriography in the preoperative evaluation of patients with known or suspected hepatocellular carcinoma and to describe the findings on CT during arterial portography and CT hepatic arteriography by which hepatocellular carcinomas may be differentiated from pseudolesions.

SUBJECTS AND METHODS

This study included 137 patients who underwent combined CT during arterial portography and CT hepatic arteriography for the preoperative evaluation of known or suspected hepatocellular carcinoma. The images were prospectively evaluated to identify focal hepatic lesions and their differential diagnoses (hepatocellular carcinoma versus pseudolesion). We assessed the diagnostic accuracy of our prospective interpretation by comparing the interpretations with the results of histopathology or follow-up imaging. We also retrospectively analyzed imaging features seen on CT during arterial portography and CT hepatic arteriography-the size, shape, and location of the lesion within the liver; attenuation of the lesion; and opacification of the peripheral portal vein branches on CT hepatic arteriography.

RESULTS

One hundred and forty-nine hepatocellular carcinomas (75 lesions confirmed at histopathology and 74 lesions on follow-up imaging) were found in 120 patients, and 104 pseudolesions (15 lesions confirmed at histopathology and 89 lesions on follow-up imaging) were found in 91 patients. The sensitivity of our prospective interpretations was 98.7%, and the specificity of our prospective interpretations was 90.4%. Our positive and negative predictive values were 93.6% and 97.9%, respectively. We found that hepatocellular carcinomas were larger, more frequently nodular, and more likely to be located intraparenchymally than were the pseudolesions (p < 0.01). Opacification of the peripheral portal vein branches on CT hepatic arteriography was detected in 36 pseudolesions (34.6%) but in none of the hepatocellular carcinomas (p < 0.01).

CONCLUSION

Combining CT during arterial portography and CT hepatic arteriography is useful for the preoperative evaluation of patients with known or suspected hepatocellular carcinoma. Familiarity with the imaging features of hepatocellular carcinomas and pseudolesions can help in the accurate differentiation of hepatocellular carcinomas from pseudolesions.

Comparison of MR and PET imaging for the evaluation of liver metastases

PURPOSE

To compare the accuracy of fluoro-18-deoxyglucose positron emission tomography (FDG-PET) and dynamic-enhanced magnetic resonance imaging (MRI) scans in the diagnosis of liver metastatic lesions from colon and other sources.

MATERIALS AND METHODS

Thirty consecutive patients with known or suspected metastatic lesions were scanned by both MRI and PET. Histopathology and/or clinical outcome, including cross-sectional imaging follow up, were used as a gold standard.

RESULTS

Of 30 patients, 16 were positive by pathology and/or clinical outcome and 14 were negative for liver metastases. The sensitivity, specificity, and positive and negative predictive values on MRI were 85.7%, 100%, 100%, and 89%, respectively, compared to 71%, 93.7%, 90.9%, and 79% on FDG-PET. The difference between the two methods was not significant (X(2) = 0.2, P > 0.05).

CONCLUSION

Our study showed no significant difference in detection of liver metastases using MRI or FDG-PET. However, MRI has advantages in spatial resolution and lesion characterization.

CT during arterial portography: effects of precontrast injection of prostaglandin E1 into the superior mesenteric artery

Prostaglandin E1 (PGE1) is a vasodilator that increases portal venous flow. Hepatic CT during arterial portography (CTAP) was performed in 42 patients with and without PGE1 to compare peak hepatic enhancement and nontumorous abnormalities. Although no significant differences in peak hepatic enhancement were observed (71 +/- 12 HU for CTAP with PGE1; 74 +/- 34 HU for CTAP without PGE1), the number of nontumorous abnormalities for CTAP with PGE1 (n = 11) was significantly lower than that for CTAP without PGE1 (n = 24) (p < 0.01, Wilcoxon signed rank test). CTAP combined with PGE1 therefore represents a useful method to study lesions of the liver, as the number of nontumorous abnormalities observed is significantly reduced and liver parenchyma can be scanned more evenly.

CT during hepatic arteriography and portography: an illustrative review

The combination of computed tomography (CT) during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) has been used for evaluation of hepatic neoplasms before partial hepatic resection. Focal hepatic lesions that can be demonstrated with CTAP and CTHA include regenerative nodules, dysplastic nodules, dysplastic nodules with malignant foci, hepatocellular carcinoma, cholangiocarcinoma, hemangioma, and metastases. CTAP is considered the most sensitive modality for detection of small hepatic lesions, particularly small hepatic tumors such as hepatocellular carcinoma and metastatic tumors. CTHA can demonstrate not only hypervascular tumors but also hypovascular tumors and can help differentiate malignant from benign lesions. However, various types of nontumorous hemodynamic changes are frequently encountered at CTAP or CTHA and appear as focal lesions that mimic true hepatic lesions. Such hemodynamic changes include several types of arterioportal shunts, liver cirrhosis, Budd-Chiari syndrome, inflammatory changes, pseudolesions due to an aberrant blood supply, and laminar flow in the portal vein. Familiarity with the CTAP and CTHA appearances of various hepatic lesions and nontumorous hemodynamic changes allows the radiologist to improve the diagnostic accuracy.

Current value of intraoperative sonography during surgery for hepatic neoplasms

Noninvasive liver imaging has developed rapidly resulting in increased accuracy for detecting primary and secondary hepatic tumors. Intraoperative ultrasonography (IOUS) was commonly considered to be the gold standard for liver staging, but the current value of IOUS is unknown in view of more sophisticated radiologic tools. The purpose of this prospective study was to evaluate the impact of IOUS on the treatment of 149 patients undergoing liver surgery for malignant disease (colorectal metastasis, 61 patients; hepatoma, 52 patients; other hepatic malignant tumors, 36 patients). The sensitivities of computed tomography (CT), helical CT, magnetic resonance imaging, and IOUS in patients with colorectal metastases were 69.2%, 82.5%, 84.9%, and 95.2% in a segment-by-segment analysis; in patients with hepatoma their sensitivities were 76.9%, 90.9%, 93.0%, and 99.3%; and in patients with other hepatic malignancies they were 66.7%, 89.6%, 93.3%, and 98.9%, respectively. Additional malignant lesions (AMLs) were first detected by inspection and palpation in 20 patients (13.4%). In another 18 patients (12.1%) IOUS revealed at least one AML. Overall, the findings obtained only by IOUS changed the surgical strategy in 34 cases (22.8%). It was concluded that IOUS, having undergone some refinement as well, still has immense diagnostic value in hepatectomy candidates. Frequently avoiding palliative liver resection and occasionally disproving unresectability as assessed by preoperative imaging, IOUS still has a significant impact on surgical decision making and should still be considered the gold standard.

Positron emission tomography for evaluation of colorectal carcinoma

Evaluation of patients with known or suspected recurrent colorectal carcinoma is now an accepted indication for FDG PET imaging. FDG PET does not replace imaging modalities such as CT for preoperative anatomic evaluation but is indicated as the initial test for diagnosis and staging of recurrence and for preoperative staging (N and M) of known recurrence that is considered to be resectable. FDG PET imaging is valuable for differentiation of posttreatment changes from recurrent tumor, differentiation of benign from malignant lesions (indeterminate lymph nodes, hepatic and pulmonary lesions), and evaluation of patients with rising tumor markers in the absence of a known source. Addition of FDG PET to the evaluation of these patients reduces overall treatment costs by accurately identifying patients who will and will not benefit from surgical procedures. Although initial staging at the time of diagnosis is often performed during colectomy, FDG PET imaging is recommended for a subgroup of patients at high risk (with elevated CEA levels) and normal CT and for whom surgery can be avoided if FDG PET shows metastases. Screening for recurrence in patients at high risk has also been advocated. FDG PET imaging seems promising for monitoring therapy, but larger studies are necessary.

Imaging the fatty liver

Even though various imaging techniques are available to detect fat, chemical-shift imaging is the most accurate for both qualitative and quantitative measurement of fat. It can be very useful in liver studies, not only because it definitively demonstrates fatty liver but also because it improves lesion detection and characterization in some cases.

Targetlike appearance of pseudotumors in segment IV of the liver on sonography

OBJECTIVE

The purpose of this study is to report a new sonographic appearance of hepatic pseudotumors. These lesions had a targetlike appearance but were caused by spared areas in fatty liver.

CONCLUSION

Although representing a frequent pattern in metastases and mycotic abscesses, a central hyperechoic core encircled by a hypoechoic halo has not yet been reported in relation to pseudotumors. Whereas multifocal target lesions in the liver suggest metastases or mycotic abscesses, an isolated target lesion in the fourth hepatic segment requires a differential diagnostic approach and a pseudotumor should be suspected because of its clinical relevance.

Superparamagnetic iron oxide-enhanced magnetic resonance imaging of the liver in beagle dogs

The role of superparamagnetic iron oxide as a tissue-specific contrast medium has been established in humans, especially for hepatic imaging. Superparamagnetic iron oxide particles exhibit a tissue-specific biodistribution to the reticuloendothelial system, where they predominantly shorten transverse T2 relaxation time. Most hepatic tumors lack Kupffer cells; therefore, the T2 of tumors remains virtually unchanged after administration of superparamagnetic iron oxide. The resulting loss of signal intensity from the liver, with unchanged tumor signal intensity, increases lesion-to-liver contrast. In this study, MR images were acquired with fast gradient echo recalled at steady state (FGRE) in five Beagle dogs before and after injection of superparamagnetic iron oxide. The effect of superparamagnetic iron oxide on signal intensity of the liver with time was assessed. A signal intensity decrease of 65.7+/-10.0% was detected at 20 minutes, and it continued to decrease until the last time point of MR scanning (200 minutes). The liver intensity of all dogs dropped to half its value after 20 minutes. The effect of motion was minimized by breath holding. Superparamagnetic iron oxide did not have any adverse effects on the dogs.

Detection of hepatocellular carcinoma: combined T2-weighted and dynamic gadolinium-enhanced MRI versus combined CT during arterial portography and CT hepatic arteriography

PURPOSE

The purpose of this study was to compare the preoperative detectability of hepatocellular carcinomas (HCCs) using combined T2-weighted and dynamic gadolinium-enhanced MRI and combined CT during arterial portography (CTAP) and CT hepatic arteriography (CTHA).

METHOD

Thirty-three patients with 43 HCCs underwent T2-weighted and dynamic gadolinium-enhanced MRI and combined CTAP and CTHA. The diagnosis was established by pathologic examination following surgical resection in 26 patients and by biopsy in 7 patients. The MR protocol included fast SE with two TEs (including T2-weighted imaging) and precontrast and gadolinium-enhanced T1-weighted fast multiplanar spoiled gradient-recalled echo images with dynamic study. The MR images of all sequences and the paired CTAP and CTHA images were independently reviewed by three radiologists. Image review was conducted on a segment-by-segment basis. Diagnostic accuracy was evaluated with receiver operating characteristic analysis.

RESULTS

The accuracies (Az values) of MRI of all sequences and combined CTAP and CTHA for all observers were 0.960 and 0.959, respectively. The mean sensitivities of MRI and CT were 90 and 94%, respectively. The differences were not statistically significant. The mean specificity of MRI (99%) was significantly higher than that of combined CTAP and CTHA (92%).

CONCLUSION

Combined T2-weighted and dynamic gadolinium-enhanced MRI is as accurate as combined CTAP and CTHA for preoperative detection of HCCs.

Impact of intraoperative sonography on resection and cryoablation of liver tumors

PURPOSE

We retrospectively analyzed the impact of intraoperative sonography (IOUS) on the management of patients referred for resection of liver tumors.

METHODS

Forty patients underwent IOUS with a 7-MHz curved-array sector transducer; in selected cases, a 5-MHz linear-array transducer attached to a color Doppler unit was also used. The number, size, and location of tumors on IOUS, including tumor proximity to or invasion of major vessels or invasion of the diaphragm, were compared to findings on preoperative imaging studies. The effect of these findings on surgical management was assessed. Unresectable lesions were treated by cryoablation under ultrasound guidance.

RESULTS

IOUS detected preoperatively unsuspected lesions in 7 patients (18%). Metastases suspected on CT arterial portography were ruled out in 2 patients (5%), and indeterminate lesions were diagnosed as cysts by IOUS in 2 other patients (5%). Vascular proximity or vascular or diaphragmatic invasion detected by IOUS rendered lesions unresectable in 4 patients (10%). Cryoablation under IOUS guidance and monitoring was attempted in 11 patients (28%) and performed successfully in 10.

CONCLUSIONS

IOUS changed the management in 38% of patients and guided cryoablation in 28% of patients. IOUS performed by an experienced sonologist is invaluable for the accurate assessment of liver tumor resectability; the detection of additional, preoperatively unknown lesions; and the guidance of cryoablation of unresectable tumors.

Pseudolesion in segment IV of the liver adjacent to the falciform ligament caused by drainage of the paraumbilical vein: demonstration by power Doppler ultrasound

A case of a pseudolesion in segment IV of the liver, adjacent to the falciform ligament, was observed on conventional CT and CT during arterial portography. The pseudolesion was caused by drainage of the paraumbilical vein. Power Doppler ultrasound was helpful in recognizing this pseudolesion by depicting that the paraumbilical vein was connected to vessels in this area. Although the direction of flow could not be determined, power Doppler ultrasound is a useful method for confirming non-invasively the aetiology of pseudolesions in this area.

Opacification of the intrahepatic portal veins during CT hepatic arteriography

PURPOSE

The purpose of this study was to ascertain the cause of opacification of the portal veins during CT hepatic arteriography (CTHA).

METHOD

A total of 155 consecutive patients with hepatocellular carcinoma were evaluated with CTHA as preoperative staging. The opacification of the portal veins during CTHA was categorized as opacification of the main portal vein, right or left branches of the main portal vein (generalized), and segmental or subsegmental portal veins (localized). Hepatic angiography was compared and possible causes were evaluated.

RESULTS

One hundred eight (70%) of 155 patients showed intrahepatic portal vein opacification at CTHA: generalized in 60 patients (39%) and localized in 48 patients (31%). Intrahepatic causes were arterioportal shunts due to hepatocellular carcinoma in 20 (19% of 108 patients), previous liver biopsy in 9 (8%), and portal vein thrombosis in 4 (4%). Extrahepatic cause was counted in 57 cases (53%) and was due to inflow of contrast material via nonmesenteric portal circulation through the gastric antrum, duodenum, and/or pancreas.

CONCLUSION

Intrahepatic portal veins are frequently opacified during CTHA, and the causes were arterioportal shunts through hepatocellular carcinoma, postbiopsy shunt, portal vein thrombosis, and inflow of contrast material via the nonmesenteric portal circulation.

Pre-operative detection of malignant hepatic tumours: value of combined helical CT during arterial portography and biphasic CT during hepatic arteriography

AIMS

The purpose of our study was to evaluate the observer performance with combined helical CT during arterial portography (CTAP) and biphasic CT hepatic arteriography (CTHA) in the pre-operative detection of malignant hepatic tumours.

METHODS

Computed tomography images obtained in 41 patients with suspected hepatic tumours were retrospectively reviewed. In a blind fashion, three off-site, independent radiologists reviewed CTAP and early-phase CTHA combined for the first review, then late-phase CTHA was added for the second review. Statistical analysis was conducted on lesion-by-lesion and segment-by-segment bases; a total of 328 liver segments including 65 segments with 74 malignant hepatic tumours ranging in size from 5 to 100 mm (mean, 21.4 mm) were analysed.

RESULTS

Sensitivity for detection of liver segments harbouring tumours of CTAP and biphasic CTHA combined (82%) was identical to that of CTAP and early-phase CTHA combined (82%). Specificity of CTAP and biphasic CTHA combined (93%) was greater than that of CTAP and early-phase CTHA combined (90%, P < 0.005). The mean confidence level for the 74 tumours significantly increased by adding late-phase CTHA (P < 0.0005). The mean confidence level for 100-142 benign perfusion abnormalities detected with CTAP and early-phase CTHA combined significantly decreased by adding late-phase CTHA (P < 0.0005).

CONCLUSION

By combining late-phase CTHA with CTAP and early-phase CTHA information, the specificity for the detection of malignant hepatic tumours rises significantly, allowing more accurate preoperative tumour detection.

Focal fatty infiltration in the posterior aspect of hepatic segment IV: relationship to pancreaticoduodenal venous drainage

OBJECTIVE

We aimed to investigate the relationship between fatty infiltration in the posterior aspect of hepatic segment IV and pancreaticoduodenal venous drainage.

METHODS

Pancreaticoduodenal arteriography was performed in 21 patients who had nontumorous portal perfusion defects in the posterior aspect of hepatic segment IV, as demonstrated on CT during arterial portography (CTAP).

RESULTS

In 10 patients, pancreaticoduodenal arteriography showed an aberrant nonportal vessel with flow toward the hepatic hilum in the venous phase. Four of the 10 patients with nonportal vessels from the pancreaticoduodenal arterial system had fatty infiltration in segment IV. In three of these four patients, the fatty infiltration was focal and localized to that area. On the other hand, none of the 11 patients without nonportal vessels from the pancreaticoduodenal arterial system had fatty infiltration in the regions corresponding to the nontumorous portal perfusion defects on CTAP. Moreover, three patients with diffuse fatty liver had a focal nonfatty area in segment IV.

CONCLUSIONS

Focal fatty infiltration in the posterior aspect of hepatic segment IV seems to be related to pancreaticoduodenal venous drainage.

Detection of hepatocellular carcinomas and dysplastic nodules in cirrhotic livers: accuracy of helical CT in transplant patients

OBJECTIVE

The purpose of this study was to evaluate the diagnostic efficacy of three-phase helical dynamic CT in the detection and characterization of hepatocellular carcinomas and dysplastic nodules in cirrhotic livers.

SUBJECTS AND METHODS

Three-phase helical dynamic CT in 41 patients with liver cirrhosis was evaluated prospectively before orthotopic liver transplantation. The numbers of hepatocellular carcinomas and dysplastic nodules were assessed in the explanted livers and compared with pretransplantation CT findings.

RESULTS

Examination of the explanted livers revealed 21 hepatocellular carcinomas in 15 patients and 23 dysplastic nodules in 10 patients. The size of the hepatocellular carcinomas was 0.6-5. 0 cm (mean, 1.9 cm), and that of the dysplastic nodules was 0.7-2.0 cm (mean, 1.0 cm). The use of helical dynamic CT enabled detection of 15 of 21 hepatocellular carcinomas (sensitivity, 71%) and nine of 23 dysplastic nodules (sensitivity, 39%). Patient sensitivity and specificity in the detection of hepatocellular carcinomas were 80% (12/15) and 96% (25/26), respectively, and for dysplastic nodules, 50% (5/10) and 97% (30/31), respectively.

CONCLUSION

Three-phase helical dynamic CT is relatively insensitive for detection of hepatocellular carcinomas and dysplastic nodules in cirrhotic livers, especially for dysplastic nodules and hepatocellular carcinomas smaller than 2 cm.

Diffuse perfusion abnormality of the liver parenchyma on angiography-assisted helical CT in relation to cirrhosis and previous treatments: a potential diagnostic pitfall for detecting hepatocellular carcinoma

We evaluated diffuse perfusion abnormality of the liver parenchyma in relation to cirrhosis and previous treatments and estimated its potential limitation in detecting hepatocellular carcinomas (HCCs) on CT arterial portography (CTAP) and CT hepatic arteriography (CTHA). Sixty-one patients of liver cirrhosis with or without HCC received both CTAP and CTHA. Irregular defects of enhancement of the liver parenchyma on CTAP were noted in 37 of 61 patients (60.7%) and compensatory arterial perfusion in these defects on CTHA was noted in 30 of 37 patients (81.1%). Most patients had segmental or mixed patterns of enhancement. In patients with severe cirrhosis, irregular enhancement was often noted. The irregularity was also more often in patients who had had previous treatments. Four of 40 HCC nodules in 18 patients with severe irregular perfusion were not detected on CTAP and CTHA. Diffuse perfusion abnormalities of the liver parenchyma on CTAP and CTHA would decrease the accuracy of tumor detection in HCC patients.

The aetiology of non-tumorous enhancement in the hepatic hilum shown on CT hepatic arteriography

The causes of non-tumorous abnormalities in the hepatic hilum seen on CT hepatic arteriography were investigated. 13 patients with non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography underwent both CT hepatic arteriography from the common hepatic artery and CT obtained during proper hepatic arteriography. The findings of non-tumorous portal defects on these two angiographic studies using helical CT were compared. In the 13 patients, 14 non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography were detected as enhanced areas in 10 regions (dorsum of segment IV, 7/10; dorsum of the lateral segment, 3/4) on CT hepatic arteriography via the common hepatic artery, but none were enhanced on CT obtained during proper hepatic arteriography. In conclusion, the main cause of non-tumorous enhancement in the hepatic hilum seen on CT hepatic arteriography is non-portal direct inflow via the parabiliary venous system.

Hepatocellular carcinoma: are combined CT during arterial portography and CT hepatic arteriography in addition to triple-phase helical CT all necessary for preoperative evaluation?

PURPOSE

To determine whether the combination of CT during arterial portography (CTAP) and CT hepatic arteriography (CTHA) provides an added benefit to triple-phase helical CT (THCT) alone in the preoperative evaluation of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Fifty-two consecutive patients with pathologically proved HCC underwent THCT (hepatic arterial, portal venous, and delayed phases) and combined CTAP and CTHA. Two radiologists reviewed the images in three sessions: first the THCT images alone, then with the CTAP images, and finally all three sets of images.

RESULTS

There were 73 pathologically confirmed HCCs. Among 72 lesions considered as HCC at THCT, 69 were proved to be HCCs. Of the additional 37 nodules interpreted as HCC at CTAP, only one was confirmed as such. Among the additional 20 lesions presumed to be HCC at combined CTAP and CTHA, only two were proved to be HCCs. The sensitivity was 94% (69 of 73 lesions) at THCT, 96% (70 of 73) with additional CTAP, and 97% (71 of 73) with all three modalities. The positive predictive value was 96% (69 of 72) at THCT, 65% (70 of 107) with additional CTAP, and 80% (71 of 89) with all three modalities.

CONCLUSION

The use of CTAP and CTHA, in addition to being invasive and costly, resulted in an unacceptably high false-positive rate without a substantial increase in sensitivity. Therefore, CTAP and CTHA are not recommended for preoperative evaluation of HCC; THCT alone is preferred.

The changing role of radiology in imaging liver tumors: an overview

The surgical and the radiological advances in liver tumors in last two decades have made some malignant tumors operable which were considered inoperable and have completely changed the expectations from radiology. However, accurate staging, that is performed by imaging modalities, has critical importance in the selection of patients who can benefit from resection. Radiologists and referring physicians, therefore, should be aware of the current concepts in imaging liver tumors. This report updates both the changing role of radiology in hepatic neoplasms and the appropriate use of radiological modalities in liver tumors.

Selection of patients for resection of colorectal metastases to the liver using diagnostic laparoscopy and laparoscopic ultrasonography

OBJECTIVE

To assess the value of diagnostic laparoscopy (DL) and laparoscopic ultrasonography (LUS) in the staging and selection of patients with colorectal liver metastasis.

SUMMARY BACKGROUND DATA

Preoperative imaging modalities such as ultrasound, computed tomography, and magnetic resonance imaging are limited in the assessment of the number and exact location of hepatic metastases and in the detection of extrahepatic metastatic disease. Consequently, the surgeon is often faced with a discrepancy between preoperative imaging results and perioperative findings, resulting in either a different resection than planned or no resection at all.

METHODS

Fifty consecutive patients were planned for DL and LUS in a separate surgical sitting to assess the resectability of their liver metastases. All patients were considered to be candidates for resection on the basis of preoperative imaging studies.

RESULTS

Laparoscopy could not be performed in 3 of the 50 patients because of dense adhesions. The remaining 47 patients underwent DL. On the basis of DL and LUS, 18 (38%) patients were ruled out as candidates for resection. Of the 29 patients who subsequently underwent open exploration and intraoperative ultrasonography, another 6 (13%) were deemed to have unresectable disease.

CONCLUSIONS

The combination of DL and LUS significantly improves the selection of candidates for resection of colorectal liver metastases and effectively reduces the number of unnecessary laparotomies.

CT arterial portography and CT hepatic arteriography in detection of micro liver cancer

AIM: To recognize the characteristic findings of micro-liver cancer (MLC) and to evaluate the effect of CT arterial portography (CTAP) and CT hepatic arteriography (CTHA) in diagnosis of MLC.

METHODS: Between April 1996 to December 1998, CTAP and CTHA were performed in 12 patients with MLC, which were not detected by conventional CT examinations. After CTHA, 3 mL-5 mL mixture of lipiodol, doxorubicin and mitoycin C were injected into hepatic artery through the catheter, and the followed up by CT three or four weeks later (Lipiodol CT Lp-CT).

RESULTS: A total of 22 micro-tumors (0.2 cm-0.6 cm in diameter) were detected in 12 patients, which manifested as small perfusion defects in CTAP and small round enhancement in CTHA. The rate of detectability of CTAP and CTHA was 68.2% (15/22) and 77.3% (17/22) respectively, and the rate of the simultaneous use of both procedures reached 86.4% (19/22). All micro-tumors were demonstrated as punctate lipiodol deposit foci in Lp-CT. After Lp-CT, the elevated serum level of α-fetoprotein (AFP) dropped to the normal level in all patients.

CONCLUSION: The CTAP and CTHA are the most sensitive imaging methods for detecting micro-liver cancer. Confirmed by the change of the elevated serum AFP level and lipiodol deposit foci in Lp-CT, small perfusion defects in CTAP and puntuate enhancement in CTHA may suggest micro-liver cancer.

Correlation of a defect of portal perfusion in the dorsal part of segment IV of the liver on CT arterial portography with inflow of the aberrant pancreaticoduodenal vein

The correlation between an aberrant pancreaticoduodenal vein and a portal perfusion defect in the dorsal part of segment IV as demonstrated on CT arterial portography (CTAP) was investigated. 14 patients with non-tumorous defects of portal perfusion in the dorsal part of segment IV of the liver parenchyma, shown on CTAP underwent CT during pancreaticoduodenal arteriography. The defect on CTAP was shown as an enhanced area resulting from non-portal venous inflow in eight (57%) of 14 patients on CT during pancreaticoduodenal arteriography. In conclusion, the non-portal venous supply via an aberrant pancreaticoduodenal vein occasionally causes a defect of portal perfusion in the dorsal part of segment IV on CT arterial portography.

Pseudolesion in segments II and III of the liver on CT during arterial portography caused by aberrant right gastric venous drainage

We report three cases of pseudolesions caused by aberrant right gastric venous drainage (AGVD) in segment II/III of the liver as demonstrated on CT during arterial portography (CTAP). On CTAP, the lesions were seen as wedge-shaped perfusion defects, and on hepatic arteriography, AGVD directed to the area with the perfusion defect was visible in all three cases. When a perfusion defect is detected at the edge of segments II/III at CTAP, a pseudolesion caused by AGVD should be suspected.

Regenerative nodules in liver cirrhosis: findings at CT during arterial portography and CT hepatic arteriography with histopathologic correlation

PURPOSE

To determine the appearance of regenerative nodules in patients with liver cirrhosis at computed tomography (CT) during arterial portography (CTAP) and CT hepatic arteriography (CTHA).

MATERIALS AND METHODS

CTAP and CTHA of the liver were performed in 28 consecutive patients with hepatocellular carcinoma (HCC) who were scheduled to undergo partial resection of the liver. Helical CTAP was performed after contrast material injection into the superior mesenteric artery followed by helical CTHA after contrast material injection into the hepatic artery. CT scans were analyzed for the presence of identifiable nodules and their size; results were correlated with gross and microscopic findings.

RESULTS

Resected livers showed cirrhosis in 20 patients, chronic hepatitis in four, and normal liver in four. Among the 20 patients with cirrhosis, regenerative nodules were demonstrated as enhancing 3-10 mm nodules surrounded by lower attenuation fibrous septa 0.8-1.5 mm thick at CTAP in seven patients and nonenhancing nodules of the same size surrounded by enhancing fibrous septa at CTHA in 15 patients. The degree of fibrosis determined the conspicuity of nodules.

CONCLUSION

Regenerative nodules in cirrhotic liver are visualized as enhancing nodules surrounded by lower attenuation thin septa at CTAP and nonenhancing nodules surrounded by enhancing fibrous septa at CTHA. CTHA is more sensitive than CTAP in depicting regenerative nodules (P < .005).

Findings of non-pathologic perfusion defects by CT arterial portography and non-pathologic enhancement of CT hepatic arteriography

AIM: To recognize the characteristic findings of non-pathologic perfusion defects with CT arterial portography (CTAP) and nonpathologic enhancement found in CT hepatic arteriography (CTHA).

METHONDS: The manifestations of nonpathologic perfusion defects with CTAP and non-pathologic enhancement found in CTHA were analyzed in 50 patients with primary hepatocellular carcinoma.

RESULTS: The false-positive rate of perfusion defects detected in CTAP was 15.1%. The shapes of perfusion defects were peripheral wedge, small, round, and patchy. The occurrence rate of non-pathologic enhancement found in CTHA was 22.0%. The shapes of non-pathologic enhancement were small, round, irregular, and wedge.

CONCLUSION: There was high frequency of non-pathologic perfusion defects detected with CTAP and non-pathologic enhancement found in CTHA. The simultaneous use of both procedures may help decrease the false-positive rate, and increase the veracity of diagnosis for hepatocellular carcinoma.

An unusual hyperplastic hepatocellular nodule in a patient with hepatitis C virus-related liver cirrhosis

Recent advances in diagnostic imaging techniques have increased the likelihood of detecting novel nodular lesions of the liver. We report here a case of unusual hyperplastic hepatocellular tumor found in a 70-yr-old woman with hepatitis C virus-related cirrhosis. A mass was incidentally detected in the right lobe by abdominal ultrasonography and confirmed by computed axial tomography (CT). Magnetic resonance imaging demonstrated that the tumor had hyperintense signal with a small hypointense region in the center and a thin, hypointense rim on T1-weighted image and a hypointense signal on T2-weighted image. CT during hepatic arteriography showed that the tumor was hypodense with a central hyperdense region, whereas CT during arterial portography revealed that the tumor was isodense and surrounded by a thin circular hypodense band with a central hypodense region. These radiographic findings suggested a diagnosis of dysplastic nodule with malignant foci of hepatocellular carcinoma. The patient underwent tumor resection. Macroscopically, the tumor, 45 x 45 x 30 mm in size, was encapsulated and had a central stellate-like scar with radiating septa. Histological examination showed a hyperplastic hepatocellular tumor without cellular, nuclear or structural atypia. The central fibrous scar contained abundant small, artery-like and vein-like vessels, whereas there were no normal portal triads but rather several portal tract-like structures lacking bile ducts in the parenchyma of the tumor. Some of the portal tract-like structures were composed of artery-like and vein-like vessels, and the others possessed vein-like vessels only. There were no bile ducts in the tumor. The nontumorous liver tissue had evidence of macronodular cirrhosis. Finally, this tumor was regarded as an unusual type of hyperplastic hepatocellular nodule encountered in cirrhotic liver, characterized by the presence of central stellate-like fibrosis and the lack of bile ducts. Although the pathogenesis of the hyperplastic lesion is unclear, it may represent a focal regenerative hepatocellular response to localized circulatory disorder.

Detection of colorectal liver metastases: prospective comparison of unenhanced and ferumoxides-enhanced magnetic resonance imaging at 1.5 T, dual-phase spiral CT, and spiral CT during arterial portography

The purpose of this study was to compare the efficacy of unenhanced and ferumoxides-enhanced magnetic resonance imaging with that of dual-phase spiral CT and spiral CT during arterial portography (CTAP) for the detection of colorectal liver metastases. Fourteen patients with liver metastases candidates for partial hepatectomy were examined with dual-phase spiral CT, unenhanced and ferumoxides-enhanced MR imaging at 1.5 T, and spiral CTAP. Imaging tests were read blinded, prospectively, quantitating number of lesions excepting CTAP which used US to exclude cysts. Subsequent intraoperative US and pathologic findings were correlated with preoperative imaging results. At surgery, 36 lesions 0.5-13 cm in diameter (mean+/-standard deviation, 2.9+/-2.1 cm) were identified. Dual-phase spiral CT depicted 21/36 (58%); precontrast MR imaging, 19/36 (53%); ferumoxides-enhanced MR imaging, 30/36 (83%); and spiral CTAP, 34/36 (94%) lesions. Ferumoxides-enhanced MR imaging was significantly more sensitive than spiral CT and unenhanced MR imaging (P < 0.01). The difference in sensitivity between ferumoxides-enhanced MR imaging and spiral CTAP was not statistically significant (P> 0.1). Spiral CTAP, however, depicted nine false-positive lesions (2 hemangiomas, 7 perfusion defects). The positive predictive value was 79% for spiral CTAP and 100% for combined pre- and postcontrast MR imaging. We conclude that ferumoxides-enhanced MR imaging is superior to unenhanced MR imaging and biphasic spiral CT for depiction of colorectal liver metastases. Further investigation is needed to clarify whether MR imaging with use of ferumoxides might replace spiral CTAP for preoperative evaluation of liver resection candidates.

Nondiseased portal perfusion defects adjacent to the right ribs shown on helical CT during arterial portography

OBJECTIVE

The purpose of our study was to assess the frequency and imaging characteristics of nonpathologic portal perfusion defects in subcapsular liver parenchyma adjacent to the right ribs as seen on CT hepatic arteriography combined with helical CT during arterial portography (CTAP).

MATERIALS AND METHODS

From January 1994 to June 1997, helical CTAP and CT hepatic arteriography were performed in 94 patients with suspected malignant hepatic tumors. The patient group comprised 66 men and 28 women ranging from 37 to 83 years old (mean, 64 years old). Three radiologists retrospectively reviewed the images obtained by CTAP to evaluate portal perfusion defects adjacent to the right ribs for location, shape, size, and correlation with findings seen on CT hepatic arteriography.

RESULTS

We identified 16 nonpathologic portal perfusion defects adjacent to the right eighth (n = 1), ninth (n = 12), and tenth (n = 3) ribs in 12 (13%) of 94 patients. The shapes of the 16 defects were circular (n = 1), oval (n = 7), wedge (n = 3), and irregular (n = 5). The defects were 10-30 mm in diameter (mean, 16.9 mm). In four (25%) of 16 locations, CT hepatic arteriography showed poorly identified, homogeneous, irregularly shaped areas of contrast enhancement corresponding to the defects seen on CTAP. The portal perfusion defects were proven to be nonpathologic on definitive surgery in four patients and on follow-up radiography in eight patients.

CONCLUSION

Helical CTAP may show nonpathologic portal perfusion defects adjacent to the right ribs. Most defects did not appear circular but rather were oval, irregular, or wedge-shaped. CT hepatic arteriography infrequently showed corresponding findings. Radiologists should recognize this potential pitfall when interpreting images obtained by helical CTAP.

Cryosurgery as a treatment for advanced stage hepatocellular carcinoma: results, complications, and alcohol ablation

BACKGROUND

The objective of this study was to investigate the use of cryosurgery and to determine whether there is a role for combined therapy with alcohol ablation in the treatment of patients with hepatocellular carcinoma.

METHODS

Twelve patients with biopsy proven hepatocellular carcinoma underwent ultrasound-guided cryosurgical ablation of their liver tumor. Postoperative alcohol ablation was performed on those patients who were found to have residual tumor or recurrence after the cryosurgical procedure.

RESULTS

Of the 12 patients (9 males, 3 females) the size of the primary tumor ranged from 3-13 cm with average size of 7 cm in greatest dimension. Most patients had advanced disease according to the TNM staging system: 9 patients had Stage IVA disease, 2 Stage III, and 1 Stage II. Three patients had residual tumors after the cryosurgical procedure. The residual tumor was treated with alcohol ablation. The 1-year survival rate for the entire group was 50% (5 of 10) and the 2-year survival rate was 30% (3 of 10). At last follow-up, 1 patient with an 8-cm tumor was disease free for 3 years and another patient with a 13-cm tumor was disease free for 2.5 years. Both of these patients had Stage IVA disease.

CONCLUSIONS

The authors found cryosurgery to be promising in the treatment of this extremely aggressive form of cancer, with the ability to prolong patient survival. Follow-up treatment with alcohol ablation is an important adjunct in treating residual tumor and controlling recurrences.

Cryosurgery as a treatment for advanced stage hepatocellular carcinoma: results, complications, and alcohol ablation

BACKGROUND

The objective of this study was to investigate the use of cryosurgery and to determine whether there is a role for combined therapy with alcohol ablation in the treatment of patients with hepatocellular carcinoma.

METHODS

Twelve patients with biopsy proven hepatocellular carcinoma underwent ultrasound-guided cryosurgical ablation of their liver tumor. Postoperative alcohol ablation was performed on those patients who were found to have residual tumor or recurrence after the cryosurgical procedure.

RESULTS

Of the 12 patients (9 males, 3 females) the size of the primary tumor ranged from 3-13 cm with average size of 7 cm in greatest dimension. Most patients had advanced disease according to the TNM staging system: 9 patients had Stage IVA disease, 2 Stage III, and 1 Stage II. Three patients had residual tumors after the cryosurgical procedure. The residual tumor was treated with alcohol ablation. The 1-year survival rate for the entire group was 50% (5 of 10) and the 2-year survival rate was 30% (3 of 10). At last follow-up, 1 patient with an 8-cm tumor was disease free for 3 years and another patient with a 13-cm tumor was disease free for 2.5 years. Both of these patients had Stage IVA disease.

CONCLUSIONS

The authors found cryosurgery to be promising in the treatment of this extremely aggressive form of cancer, with the ability to prolong patient survival. Follow-up treatment with alcohol ablation is an important adjunct in treating residual tumor and controlling recurrences.