CT detection of hepatic metastases with Ethiodized Oil Emulsion 13

The use of an experimental liposoluble contrast agent-Ethiodized Oil Emulsion 13 (EOE 13)--is described in hepatic computed tomography (CT) of 23 oncologic patients. Without exception, all the hepatic metastases were better delineated in the EOE 13 enhanced scans. The postcontrast scans also detected an increased number of lesions but not all were malignant. There is no specificity to the increased lesion detection. Various splenic abnormalities were detected. Very few minor side effects and no major side effects were caused by the contrast media. We feel that with time, hepatic specific agents such as EOE 13 will become the contrast media of choice in hepatic CT examinations. Also, CT with hepatic specific agents may become the preoperative examination of choice in candidates for partial hepatectomy.     

Comparison of contrast media injection rates and volumes for hepatic dynamic incremented computed tomography

Contrast injection techniques now in use for hepatic dynamic incremented computed tomography (DICT) were designed for scanners using slower scan acquisition rates than the currently available 6 to 12 scans/minute. Of 53 patients examined, (1) 19 received a conventional 2-minute injection of 150 or 120 mL of 60% contrast material selected by patient weight; (2) 19 received the same doses within 1 minute; and (3) 15 received 20% lower doses within 1 minute. The faster injection groups 2 and 3 reached peak enhancement sooner (57 and 60 seconds vs. 97 seconds) with similar or higher peak hepatic enhancement (73 and 64 HU vs. 58 HU) and equivalent hepatic enhancement (52 and 48 HU vs. 54 HU) after 150 seconds. Because detecting neoplastic liver lesions often depends on enhancement, 1-minute injections of high doses of contrast material with rapid scan rates may be superior to 2-minute injections. When cost or dose-related toxicity are important, 1-minute injections of 20% lower contrast doses may be considered.     

Spiral versus conventional CT in soft tissue diagnosis.

Spiral volumetric computed tomography (SVCT) has been predicted to improve vascular and organ enhancement with little effect on image quality. To see if this was the case, we studied 100 patients referred for computed tomography where we would normally have performed dynamic incremental computed tomography (DICT). Patients were randomly allocated to undergo either standard DICT or SVCT. The resulting images were analysed for overall quality, the degree of contrast medium enhancement and the extent of artefacts associated with the technique. No statistically significant difference in overall image quality between SVCT and DICT was found, apart from images of the hepatic parenchyma where the quality was significantly worse on SVCT (P < 0.05) due to the low mA permissible. Contrast enhancement was better with SVCT, although only for the thorax (P < 0.01) and the group taken as a whole (P < 0.01) did this improvement reach statistical significance. There was no statistically significant difference between the extent of artefacts observed in the two techniques. As expected, all acquisition times were shorter using SVCT. The benefits of SVCT have been well described and include the absolute contiguity of the reconstructed images and the ability to obtain many images at peak contrast enhancement. We have confirmed the latter effect. We are now also satisfied that there is no appreciable loss of overall image quality except where large volumes of solid tissue are being examined (e.g. liver).     

Computed tomography of necrotic hepatic metastases.

Seven patients with necrotic liver metastases were evaluated by computed tomography. The metastases demonstrated low attenuation areas varying from a small central portion to the entire lesion. Other findings included mural nodules and fluid-fluid levels. Possible etiologies for necrotic metastases are presented and their differential diagnosis is discussed.     

Preoperative segmental localization of hepatic metastases: utility of three-dimensional CT during arterial portography

To evaluate the accuracy of a fast three-dimensional (3D) reconstruction technique in determining the segmental location of hepatic metastases, 14 patients (40 metastases) were prospectively investigated before surgery with dynamic two-dimensional (2D) computed tomography during sequential arterial portography (CTAP). All patients underwent subsequent hepatic tumor resection within 4 days. After computer-generated mapping of hepatic venous structures with high attenuation and metastases with low attenuation, 3D reconstruction was performed. Thirty-six of the 40 lesions (90%) were detected with 2D and 3D CTAP. The accuracy in determining the segmental location of hepatic metastases was 78% (28 of the 36 metastases) for 2D CTAP and 94% (34 of the 36 metastases) for 3D CTAP. The difference in localization rates between 2D CTAP and 3D CTAP was statistically significant. The 3D CTAP technique provides vital data unattainable with other imaging modalities that improve the preoperative assessment of the resectability of hepatic metastases and allows planning a safer surgical approach.     

Solitary hepatic metastasis: Comparison of dynamic contrast-enhanced CT and MR imaging with fat-suppressed T2-weighted,Breath-hold T1-weighted FLASH,and dynamic gadolinium-enhanced FLASH sequences

Twenty consecutive cancer patients with a solitary hepatic metastasis detected with dynamic contrast-material—enhanced computed tomography (CT) who were considered for hepatic resection underwent magnetic resonance (MR) imaging within 18 days after CT. Histologic confirmation was obtained in all lesions. CT depicted 20 solitary lesions. MR imaging showed a solitary lesion in 14 patients, two lesions in three patients, and more than two lesions in three patients, for a total of 37 lesions. Twenty-three lesions less than 2 cm in diameter were missed with CT, and six lesions less than 1.3 cm in diameter were missed with MR imaging. MR imaging was superior to CT in the detection of hepatic metastases on a patient-by-patient basis (P <.01). The results suggest that MR imaging is superior to dynamic contrast-enhanced CT for the detection of hepatic metastases.     

Contrast enhancement technique for dynamic hepatic computed tomographic scanning

A study comparing precontrast and survey postcontrast dynamic computed tomographic (CT) scanning was performed on 60 patients who had suspected hepatic metastases. An incremental dynamic technique was used during and following a 50-g iodine load administered over two minutes. The survey postcontrast dynamic technique was superior in both sensitivity and contrast differentiation and yielded no known false-negative examinations. No postprocedure renal dysfunction was observed. High-dose contrast-material delivery in conjunction with incremental dynamic CT scanning appears to be the most suitable technique for performing postcontrast hepatic CT examinations.     

Diagnosis of hepatic neoplasms using CT arterial portography and CT hepatic arteriography

Both computed tomography arterial portography (CTAP) and CT hepatic arteriography (CTHA) are CT techniques with angiographic assistance. The detection sensitivity of these techniques is high because marked lesion contrast can be obtained using direct delivery of contrast materials to the liver parenchyma or the tumors. The use of CTAP and CTHA may improve therapeutic results after transarterial embolization therapy for hepatocellular carcinomas because of their high diagnostic accuracy. Findings on CTAP or CTHA can sometimes help characterize the hepatic focal lesions. Thus, CTAP and CTHA are frequently performed as pretreatment examinations, although they are invasive compared to intravenous (IV) contrast-enhanced CT or magnetic resonance imaging. However, there are some potential pitfalls, such as nontumorous perfusion abnormalities. CTAP and CTHA are less effective for evaluation of patients with cirrhosis and portal hypertension. This article presents a current overview of CTAP and CTHA technique for diagnosis of hepatic neoplasms.     

Hepatic venography in the surgical assessment of hepatic tumours

Hepatic venography was performed on 80 patients with hepatic tumours for the pre-operative assessment of resectability. Sixty-six patients subsequently underwent laparotomy, 27 undergoing hepatic resection. Forty-two patients had metastases from colo-rectal primaries, 19 hepatocellular carcinoma and 19 a variety of other tumours. The type and frequency of the abnormalities shown on venography were noted for each tumour category and for their hepatic segmental distribution. The results of venography were compared with those of arteriography, computed tomography and ultrasound and with the findings at laparotomy. Displacement was the commonest abnormality seen while encasement or obstruction occurred less frequently and tumour invasion was rare. The sensitivity of venography in correctly identifying the segmental distribution of tumour deposits was 41%. Sensitivity was poorest with tumours in the left lobe (31%) and bilobar tumours (0%). Venography was most sensitive in detecting tumour involvement of the major segmental hepatic veins and inferior vena cava (100%). Peripheral colo-rectal metastases frequently produced no venographic abnormality. Hepatic venography provides no additional information to arteriography, computed tomography or ultrasound in patients with peripheral or bilobar tumour deposits. Some additional information may be obtained with central tumours and venography is the most accurate means of detecting tumour involvement of the major segmental hepatic veins.     

Detection of hypovascular hepatic metastases at triple-phase helical CT: sensitivity of phases and comparison with surgical and histopathologic findings

PURPOSE: To compare the respective sensitivities of unenhanced, arterial-dominant, and portal-dominant phase helical computed tomography (CT) in the preoperative depiction of hypovascular hepatic metastases by using intraoperative ultrasonographic (US) and histopathologic findings as the standard of reference. MATERIALS AND METHODS: In this prospective study, 32 patients with 59 surgically and histopathologically proved hypovascular hepatic metastases underwent triple-phase helical CT of the liver, which included unenhanced, arterial-dominant, and portal-dominant phase scanning. Images from each phase were separately analyzed by three readers, and disagreements were resolved with consensus readings. The findings on CT images were compared with intraoperative US and histopathologic findings on a lesion-by-lesion basis to determine the sensitivity of each imaging phase. Statistical review of the lesion-by-lesion analysis was performed by using the Wilcoxon rank sum test. RESULTS: Among 59 hepatic metastases, unenhanced, arterial-dominant, and portal-dominant phase helical CT imaging depicted 39 (66.1%; 95% CI: 53.3%, 76.8%), 44 (74.5%; 95% CI: 62.2%, 83.9%), and 54 (91.5%; 95% CI: 81.6%, 96.3%) metastases, respectively. Portal-dominant phase imaging depicted significantly more hypovascular hepatic metastases than did unenhanced (P <.001) or arterial-dominant (P <.01) phase imaging (Wilcoxon test). CONCLUSION: Preoperative use of triple-phase helical CT in patients with hypovascular hepatic metastases may not be warranted. Portal-dominant phase helical CT imaging allows depiction of significantly more hypovascular hepatic metastases than does imaging during any of the other phases.     

Detection of hepatic metastases by proton spectroscopic imaging. Work in progress

Fourteen patients with hepatic metastases underwent magnetic resonance (MR) imaging using both the conventional spin-echo (SE) technique and the opposed phase of the proton spectroscopic imaging method. The opposed image showed more lesions than the conventional SE image in five patients and provided better contrast between the liver parenchyma and metastases in two patients. Four of these seven patients had associated fatty infiltration of the liver. When compared with the computed tomography (CT) scan, the opposed image either showed more lesions or provided better contrast in six patients, four of whom had fatty infiltration. More significantly, the MR image showed several 1-cm lesions not shown by the CT scan in one patient. Our study discloses the possible explanations for the increased sensitivity of the opposed image in detecting hepatic metastases.     

The role of F-18 FDG positron emission tomography in preoperative assessment of the liver in patients being considered for curative resection of hepatic metastases from colorectal cancer

PURPOSE: The authors' goal was to determine the sensitivity and specificity of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) for identifying patients with hepatic metastases from colorectal cancer and the accuracy of PET for determining the number and distribution of lesions within the liver. Intraoperative sonography and surgical inspection and palpation were used as the reference standard. METHODS: Twenty-three patients being evaluated for surgical resection of hepatic metastases from colorectal carcinoma underwent FDG PET before operation. Findings of the PET studies were reviewed in a blinded, retrospective manner, with the results compared with the findings of intraoperative sonography and surgical exploration. Lesions of all sizes were considered in the analysis. RESULTS: The FDG-PET results were positive in 21 of the 22 patients ultimately found to have metastatic disease to the liver, and they were negative in the single patient without metastases. Therefore, for identification of patients with hepatic metastatic disease, PET has a sensitivity of 95% and a specificity of 100%. In all, 48 metastatic lesions were identified in these patients, of which 38 (79%) were identified on PET images. The probability of lesion detection by PET was directly correlated with lesion size (P < 0.01). The assessment of lobar disease distribution in the liver was discordant between PET and surgery in 3 of 23 (13%) patients. CONCLUSIONS: In patients being evaluated for potential curative resection of hepatic metastases from colorectal cancer, FDG PET is accurate for the identification of the presence or absence of metastatic disease to the liver. However, detection of individual lesions depends on their size, and determination of lesion number and distribution within the liver is more accurately accomplished with intraoperative sonography.     

Aortic and hepatic enhancement and tumor-to-liver contrast: analysis of the effect of different concentrations of contrast material at multi-detector row helical CT

PURPOSE: To investigate the effect of different iodine concentrations of contrast material on aortic and hepatic enhancement and the detectability of hypervascular hepatocellular carcinoma (HCC) with multi-detector row computed tomography (CT) and a uniphasic contrast material injection technique. MATERIALS AND METHODS: Two hundred one patients with known or who were suspected of having HCC underwent multi-detector row CT; 58 patients with hypervascular HCC were identified. First-, second-, and third-phase scanning was started with the aortic arrival times plus 15 seconds, plus 30 seconds, and plus 105 seconds, respectively. All patients were assigned randomly into two groups. Patients in groups A and B received iopamidol with an iodine concentration of 300 mg/mL and 370 mg/mL, respectively, with the same total iodine load per patient per body weight. The liver and aorta enhancement and tumor-to-liver contrast (TLC) were measured. Depiction of hepatic arteries was evaluated visually by two radiologists. RESULTS: During the first phase, aortic enhancement was significantly (P <.01) higher in group B, with no significant difference in hepatic enhancement between the two groups. During the second phase, aortic enhancement was significantly (P <.01) higher in group A, with no significant difference in hepatic enhancement. The TLC was significantly (P <.01) higher in group B during the first phase, but there was no significant difference between the two groups during the second phase. There was no significant difference in any parameters between the two groups during the third phase. Depiction of the hepatic arteries in group B was significantly (P <.05) superior to that in group A. CONCLUSION: In the arterial phase, administration of a higher concentration of contrast material is effective for a significantly higher TLC.     

Detection of liver metastases from colorectal cancer: comparison of intraoperative US and CT during arterial portography.

A prospective study was performed to compare the sensitivities of intraoperative ultrasound (US) and computed tomography during arterial portography (CTAP) in the depiction of hepatic metastases from colorectal cancer. Twenty-five patients with hepatic metastases from colorectal cancer were evaluated. All patients underwent partial hepatectomy, and 56 metastases were pathologically proved. Preoperatively, CTAP depicted 51 of the 56 metastases (91%). Intraoperative US depicted 54 of the 56 metastases (96%). Intraoperative US depicted three metastases (5%) that were not depicted with CTAP and two that were missed with palpation (3%). Furthermore, intraoperative US did not demonstrate any false-positive lesions. There was no statistically significant difference in sensitivity between the two techniques. The authors concluded that intraoperative US does not enable detection of more liver metastases from colorectal cancer when CTAP is considered as the preoperative standard of reference. Nevertheless, the results of the study suggest that intraoperative US and CTAP are complementary techniques, and the preoperative use of CTAP for determining the feasibility of hepatic resection cannot prevent the use of intraoperative US.     

Comparison of pre- and postcontrast CT in hepatic masses

A comparison of hepatic computed tomography (CT) before and after administering intravenous contrast material was performed 85 times on 81 patients suspected of having hepatic mass lesions. Both pre- and postcontrast computed tomography were sensitive and specific in over 88% of cases, with no statistical difference in accuracy between the techniques. However, postcontrast scans were generally preferred because of increased diagnostic confidence and improved characterization of associated abnormalities. The recent advent of rapid sequential scanning after intravenous administration of a large volume of contrast material seems to further improve diagnostic confidence. When high-resolution CT equipment is used, postcontrast CT alone is the preferred method for CT evaluation of patients with suspected liver lesions.     

Colorectal tumors: scintigraphy with In-111 anti-CEA monoclonal antibody and correlation with surgical, histopathologic, and immunohistochemical findings

A prospective clinical study of 17 patients with a histologic diagnosis of colorectal carcinoma proved at colonoscopy and surgery was performed with indium-111 anticarcinoembryonic-antigen (CEA) monoclonal antibody (MoAb), ZCE-025. MoAb scanning depicted nine of 16 primary colorectal carcinomas on planar scintigrams (true-positive findings = 56%) and ten of 16 lesions on single-photon emission computed tomography (SPECT) scans (true-positive findings = 62%). Liver metastases were detected in three of three patients, and lymph node metastases were detected in one of four patients. Immunohistochemical examination for CEA in resected colorectal cancer tissues demonstrated a positive correlation between MoAb imaging of primary lesions and cytoplasmic-stromal intracellular CEA distribution. There was no correlation between CEA serum levels and lesion detectability with MoAb scanning.     

Computed tomography and sonographic findings of hepatic metastases from gastrointestinal stromal tumors after chemotherapy

OBJECTIVE: The purpose of this study was to evaluate the computed tomography (CT) and sonographic findings in patients with hepatic metastases from gastrointestinal stromal tumors (GISTs) after STI-571 treatment. METHODS: Computed tomography and sonographic findings of 8 lesions in 6 patients with hepatic metastases from GISTs that were treated with STI-571 were retrospectively analyzed. The change in size, attenuation, and echogenicity of the hepatic metastases from GISTs after STI-571 treatment was evaluated. RESULTS: After treatment with STI-571, the hepatic metastases were decreased in size and the attenuation of the hepatic metastases was homogeneously hypodense on CT. Sonography revealed the hepatic metastases to be centrally cystic with a thin wall (n = 4) or predominantly solid (n = 4) after STI-571 treatment. On color Doppler sonography, no blood flow was identified within the solid portion of the mass. CONCLUSION: After treatment with STI-571, although the hepatic metastases from GISTs exhibit a cystic appearance on CT, they may appear as solid masses on sonography.     

Role of computed tomography in the follow-up of hepatic and peritoneal metastases of GIST under imatinib mesylate treatment: a prospective study of 54 patients

PURPOSE: To prospectively analyze the evolution of hepatic and peritoneal unresectable metastases from gastrointestinal stromal tumors (GIST) under imatinib mesylate, a new targeted treatment, which induces changes in lesion structure. MATERIALS AND METHODS: 54 patients with metastases from GIST underwent an abdominal and pelvic computed tomography examination without and with contrast enhancement, before and during treatment with imatinib mesylate. The number and size of lesions and contrast enhancement were noted before treatment and every 2 weeks for the first 2 months, then every 2 months for the first year of treatment and every 3 months thereafter. RESULTS: 27 patients presented with both hepatic and peritoneal metastases, 14 had only peritoneal and 13, only hepatic disease. On baseline imaging, all metastases were hypodense heterogeneous lesions with progressive, concentric enhancement. After treatment (mean duration of follow-up: 23 months) metastases decreased in size number and enhancement in 35/54 patients, remained stable in 2 patients and increased in 14 patients. In 13/39 patients with hepatic metastases a cyst-like appearance was noted. Reactivation after a partial response appeared first as a focal, peripheral, solid nodule in the wall of a cystic lesion, or an increase in lesion density, before size regrew. CONCLUSION: Besides the classic size criterion, a decrease in density and in contrast enhancement with stable "near cystic" lesions signifies a good response. A more aggressive approach (surgery or radiofrequency ablation) may be indicated for initially focal recurrences with a stable size.     

Role of multidetector CT and FDG-PET/CT in the diagnosis of local and distant recurrence of resected rectal cancer

PURPOSE: The aim of this study was to compare the diagnostic value of multidetector computed tomography (MDCT) and F18-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT) for the detection of local and distant recurrence in patients operated on for rectal cancer. MATERIALS AND METHODS: Sixty-seven patients who underwent radical surgery for rectal cancer and were followed up with FDG-PET/CT and MDCT were included in this retrospective study. The FDG-PET/CT and MDCT findings were independently compared with histological sampling or 2 years' follow-up. RESULTS: Local recurrence occurred in 15/67 patients. MDCT diagnosed local recurrence in 15/15 cases and FDG-PET/CT in 14/15. Sensitivity and specificity were 100% and 98% for MDCT and 93% and 98% for FDG-PET/CT, respectively. Hepatic lesions were found in 17/67 patients. All hepatic metastases were detected by both techniques. Pulmonary metastases occurred in 8/67 patients: they were correctly identified in all cases by MDCT and in 6/8 by FDG-PET/CT. CONCLUSIONS: MDCT and FDG-PET/CT showed high sensitivity and specificity for the detection of local recurrence of rectal cancer. Both techniques were equally accurate for the detection of hepatic metastases. MDCT showed slightly higher sensitivity and positive predictive value in detecting pulmonary metastases compared with FDG-PET/CT.     

Critical study of the methods available for detecting hepatic metastases (author's transl)

Based on a review of data in the published literature, and the results of their personal experience in the Antoine-Lacassagne Centre in Nice, the authors discuss the different techniques employed for the detection of hepatic metastases: biological tests, liver needle biopsy, laparoscopy, laparotomy, hepatic angiography, scintigraphy, ultrasonography, and computed tomography. In 90 p. cent of cases liver biological tests and ultrasonography were sufficient to eliminate or confirm the presence of hepatic metastases. When there is no correlation between the results of the different non-traumatic techniques, one is justified in proposing a liver biopsy under laparoscopy.