Dual-phase helical CT of pancreatic adenocarcinoma: assessment of resectability before surgery

OBJECTIVE: The aim of our study was to prospectively evaluate the accuracy of dual-phase helical CT in the preoperative assessment of resectability in patients with suspected pancreatic cancer using surgical and histopathologic correlation. SUBJECTS AND METHODS: Between January 1999 and December 2000, 76 patients with suspected pancreatic cancer underwent preoperative evaluation and staging with dual-phase helical CT (3-mm collimation for pancreatic phase, 5-mm collimation for portal phase). Iodinated contrast material was injected IV (170 mL at a rate of 4 mL/sec); acquisition began at 40 sec during the pancreatic phase and at 70 sec during the portal phase. Three radiologists prospectively evaluated the imaging findings to determine the presence of pancreatic tumor and signs of unresectability (liver metastasis, vascular encasement, or regional lymph nodes metastasis). The degree of tumor-vessel contiguity was recorded for each patient (no contiguity with tumor, contiguity of < 50%, or contiguity of > or =50%). RESULTS: Thirty-nine patients with pancreatic adenocarcinoma were surgically explored. Curative resections were attempted in 34 patients and were successful in 25. The positive predictive value for resectability was 73.5%. Nine patients considered resectable on the basis of CT findings were found to be unresectable at surgery because of liver metastasis (n = 5), vascular encasement (n = 2), or lymph node metastasis (n = 2). We found that the overall accuracy of helical CT as a tool for determining whether a pancreatic adenocarcinoma was resectable was 77% (30/39 patients). CONCLUSION: Dual-phase helical CT is a useful technique for preoperative staging of pancreatic cancer. The main limitation of CT is that it may not reveal small hepatic metastases.     

胰腺癌的可切除性评价(经动脉双期螺旋CT与血管造影的对比分析)

分别采用经动脉双期螺旋ＣＴ扫描和选择性血管造影,对胰腺癌的可切除性进行术前前瞻性评价,以确定各自的临床应用价值。方法对１５例胰腺癌术前均行选择性造影及经动脉增强双期螺旋ＣＴ扫描,对胰腺癌的临床应用价值。结论经动脉双期螺旋ＣＴ扫描弥补了血管造影的不足,能够更为准确,全面地评价胰腺癌的可切除术,具有较高的临床应用价值。     

Liver metastases from colorectal carcinoma: detection with continuous CT angiography.

A diagnostic approach to assess liver metastases from colorectal carcinoma was prospectively evaluated in 30 patients with and without metastases on the basis of findings at conventional computed tomography (CT). With the technique, termed continuous CT angiography (CCTA), CT data were continuously sampled for 24 seconds at the same section level after initiation of a 3-second injection of 10-20 mL of contrast medium in the common hepatic artery. The procedure was repeated for each contiguous section level of the liver. Findings at preoperative ultrasound (US), conventional CT, and CCTA were compared with those at intraoperative US and surgical exploration as the standard of reference. Forty-four liver metastases were identified in 16 patients, and 14 patients had no metastases. CCTA had a sensitivity of 98% (43 lesions identified) and higher accuracy (81% [54 of 67 diagnoses]) than US and conventional CT. The data indicate that CCTA can supplement information obtained with conventional imaging techniques in patients who must undergo hepatic surgery because of metastases from colorectal carcinoma.     

Liver metastases from colorectal cancers: detection with CT during arterial portography

A total of 45 metastases to the liver from colorectal cancer were resected in 22 patients. The detectability of these lesions with the following modalities was determined: real-time ultrasound (US), computed tomography (CT), selective celiac arteriography (SCA), infusion hepatic angiography (IHA), CT during arterial portography (CTAP), and CT following intraarterial injection of iodized poppyseed oil (Lipiodol). The total detection rate (sensitivity) was 58% for US, 63% for CT, 27% for SCA, 50% for IHA, 84% for CTAP, and 38% for CT with iodized oil. Ten of 18 lesions less than 15 mm in largest diameter were demonstrated preoperatively by CTAP only. CTAP is useful in clarifying the locations of the lesions in the liver and should always be performed before liver metastases from colorectal cancer are resected.     

Preoperative assessment of resectability of hepatic metastases from colonic carcinoma: CT portography vs sonography and dynamic CT.

OBJECTIVE. A retrospective study was performed to determine the influence of CT portography vs sonography and dynamic CT on the preoperative assessment of the resectability of hepatic metastases from colorectal cancer. MATERIALS AND METHODS. Results of sonography, bolus dynamic CT, and CT portography in 28 patients who underwent surgical exploration (resection or intraarterial catheter placement) for hepatic metastases from colorectal cancer were retrospectively reviewed by two abdominal radiologists and one hepatic surgeon. For each patient, the resectability and surgical approach were decided on the basis of the results of combined sonography-bolus dynamic CT and compared with the decision made from the CT portographic results alone. The final approach suggested was compared retrospectively with the surgical procedure actually performed. RESULTS. Sixty-nine metastases were identified at surgery and pathologically proved. Combined sonography-bolus dynamic CT and CT portography showed 52 (75%) and 64 (93%) metastases, respectively. Twelve metastases in five patients were seen only with CT portography. In four patients, CT portography depicted additional metastases, which changed the surgical approach that had been chosen on the basis of results of sonography and bolus dynamic CT. In one patient, CT portography showed four additional metastases, precluding hepatic resection. CONCLUSION. Findings from CT portography provide vital data unattainable with sonography and bolus dynamic CT that improve the preoperative assessment of the resectability of liver metastases from colonic carcinoma.     

Revealing hepatic metastases from colorectal cancer: value of combined helical CT during arterial portography and CT hepatic arteriography with a unified CT and angiography system

OBJECTIVE: The purpose of our study was to evaluate the use of combined helical CT during arterial portography and CT hepatic arteriography in the preoperative assessment of hepatic metastases from colorectal cancer using a unified CT and angiography system. MATERIALS AND METHODS: Fifty-four patients with hepatic metastases from colorectal cancer preoperatively underwent combined CT during arterial portography and CT hepatic arteriography using the unified CT and angiography system. Three radiologists independently and retrospectively reviewed the images of CT during arterial portography alone, CT hepatic arteriography alone, and combined CT during arterial portography and CT hepatic arteriography. Image review was conducted on a segment-by-segment basis; a total of 432 hepatic segments with (n = 103) 118 metastatic tumors ranging in size from 2 to 160 mm (mean, 25.8 mm) and without (n = 329) tumor were reviewed. RESULTS: Relative sensitivity of combined CT during arterial portography and CT hepatic arteriography (87%) was higher than that of CT during arterial portography alone (80%, p < 0.0005) and CT hepatic arteriography alone (83%, p < 0.005). Relative specificity of CT hepatic arteriography alone (95%, p < 0.0005) and combined CT during arterial portography and CT hepatic arteriography (96%, p < 0.0001) was higher than that of CT during arterial portography alone (91%). Diagnostic accuracy, determined by a receiver operating characteristic curve analysis, was greater with combined CT during arterial portography and CT hepatic arteriography than with CT during arterial portography alone (p < 0.05) or CT hepatic arteriography alone (p < 0.01). CONCLUSION: Using a unified CT and angiography system, we found that combined CT during arterial portography and CT hepatic arteriography significantly raised the detectability of hepatic metastases from colorectal cancer.     

Role of PET/CT in the detection of liver metastases from colorectal cancer

Purpose

The aim of this study was to compare the diagnostic accuracy of 2-[fluorine-18] fluoro-2-deoxy-D-glucose positron emission tomography (¹⁸F-FDG-PET) and computed tomography (CT) with PET/CT in the detection of liver metastases during tumour staging in patients suffering from colorectal carcinoma for the purposes of correct surgical planning and follow-up.

Materials and methods

A total of 467 patients underwent a PET/CT scan using an iodinated contrast medium. We compared images obtained by the single PET scan, the single CT scan and by the fusion of the two procedures (PET/CT). The final diagnosis was obtained by histological examination and/or by the follow-up of all patients, including those who did not undergo surgery or biopsy.

Results

The PET scan had 94.05% sensitivity, 91.60% specificity and 93.36% accuracy; the CT scan had 91.07% sensitivity, 95.42% specificity and 92.29% accuracy. The combined procedures (PET/CT) had the following values: sensitivity 97.92%, specificity 97.71% and accuracy 97.86%.

Conclusions

This study indicates that PET/CT is very useful in staging and restaging patients suffering from colorectal cancer. It was particularly useful when recurrences could not be visualised either clinically or by imaging despite increasing tumour markers, as it guaranteed an earlier diagnosis. PET/CT not only provides high diagnostic performance in terms of sensitivity and specificity, enabling modification of patient treatment, but it is also a unique, high-profile procedure that can produce cost savings.     

Hepatic metastases in patients with colorectal cancer: relationship between size of metastases,standard of reference,and detection rates

PURPOSE: To determine the relationship between the size of hepatic metastases, the standard of reference, and the reported detection rate in patients with colorectal cancer. MATERIALS AND METHODS: With use of a MEDLINE search (January 1994 to January 2001), articles were selected that contained original results on detection of hepatic metastases of colorectal cancer, categorized for size in at least two categories, with use of helical computed tomography (CT), helical CT at arterial portography, or magnetic resonance imaging. Results were compared with the size distribution of hepatic metastases in 47 consecutive patients with colorectal carcinoma, which were detected by using a combination of intraoperative ultrasonography (US) and palpation. RESULTS: Seven studies met all predefined criteria. Four studies involved intraoperative US in all patients and demonstrated a significant negative correlation (-0.988) between detection rate and fraction of small metastases. These studies had a higher fraction and lower detection rate of small metastases and a lower overall detection rate. A majority (58% [145 of 252]) of metastases in the study population were smaller than 20 mm. CONCLUSION: Few articles adequately describe the standard of reference and size distribution of hepatic lesions. Hepatic metastases of colorectal cancer are frequently smaller than 20 mm. When the standard of reference is suboptimal, many small metastases are excluded from analysis, and detection rates are therefore inflated.     

Intestinal metastases from gastric adenocarcinoma: helical CT findings

PURPOSE: The purpose of this work was to describe the helical CT findings of intestinal metastasis from gastric adenocarcinoma. METHOD: Twenty-three patients with intestinal metastasis from gastric adenocarcinoma found at helical CT were included. CT findings and clinical and pathologic data were reviewed. RESULTS: The most common characteristic finding was target-like concentric bowel wall thickening (thick inner high-outer low, n = 18) involving multiple long segments with progressive thickening of the enhancing inner layer. Fifteen cases (65%) involved multiple sites, and the ascending colon (n = 12) and rectum (n = 11) were the two most common sites. Peritoneal carcinomatosis (n = 15, 65%) and bowel obstruction (n = 14, 61%) were common associated findings. Regarding the primary lesion, the majority was linitis plastica (n = 16) and poorly differentiated adenocarcinoma with or without signet-ring cell differentiation (n = 14). CONCLUSION: Intestinal metastasis from gastric adenocarcinoma, especially of the linitis plastica type, most commonly showed target-like long segmental wall thickening with a characteristically thick inner enhancing layer on helical CT.     

Hepatic metastases: randomized, controlled comparison of detection with MR imaging and CT

To determine the accuracy of magnetic resonance (MR) imaging relative to computed tomography (CT) in the diagnosis of liver metastases, a randomized, controlled study was conducted of 135 subjects, including 57 with cancer metastatic to the liver, 27 with benign cysts or hemangiomas, and 51 without focal liver disease. The sensitivity of MR imaging for detecting individual metastatic deposits was 64%, significantly greater than 51% for CT (P less than .001); the difference in sensitivity for identifying patients with one or more hepatic metastases was less (82% for MR imaging vs. 80% for CT). In patients without hepatic metastases, the specificity of MR imaging was 99% versus 94% for CT. Significant differences were found between individual MR pulse sequences in detection of individual lesions. The sensitivity of both T1-weighted spin-echo (SE) (64%) and inversion-recovery (IR) (65%) pulse sequences was significantly (P less than .001) greater than either the TE (echo time) 60 msec (43%) or TE 120 msec (43%) T2-weighted pulse sequences. Overall, the accuracy of a single T1-weighted (10-minute) pulse sequence was superior to that of contrast-enhanced CT.     

Axillary lymph node metastases in breast cancer: preoperative detection with US

The importance of axillary node status in the prognosis of breast cancer led the authors to conduct a prospective study comparing the value of clinical examination with ultrasound (US) performed by a transpectoral approach. All 60 patients examined underwent axillary dissection. Sensitivity was 45.4% for clinical examination versus 72.7% for US. US provides valuable information for breast cancers treated solely by irradiation, after insufficient dissection, and for large tumors not amenable to primary surgery. When the nodal region is treated by surgery and/or radiotherapy, local monitoring with US appears unnecessary owing to the low incidence of nodal recurrence.     

Dual phase helical CT versus portal venous phase CT for the detection of colorectal liver metastases: correlation with intra-operative sonography, surgical and pathological findings

AIM: To assess whether dual phase helical computed tomography (DPCT) of the liver improves the detection of colorectal liver metastases compared with portal venous phase (PVP) imaging alone. MATERIALS AND METHODS: DPCT was performed in 33 consecutive patients before laparotomy for resection of colorectal liver metastases. CT comprised 8-mm slice collimation with a pitch of 1 to 1.25; imaging was commenced 20-25 and 65-70 s after the start of injection of 150 ml of contrast medium at 5 ml/s to coincide with hepatic arterial phase (HAP) and PVP contrast enhancement, respectively. Four blinded observers independently reviewed the HAP, PVP and DPCT images recording the site and size of all lesions. Alternative-free response receiver operating characteristic (AFROC) methodology was used to analyse the results, which were correlated with surgery, intra-operative ultrasound and histology. RESULTS: The mean observer sensitivities for malignant lesion detection were 75.3% for DPCT, 69.7% for PVP imaging and 66.7% for HAP imaging alone. There was a statistically significant improvement in malignant lesion detection using DPCT when compared with PVP imaging alone (P < 0.05). The mean areas under the AFROC curves were 0.84 for DPCT and 0.82 for PVP (P < 0.03) imaging alone. CONCLUSION: The detection of colorectal liver metastases was marginally better with DPCT than with PVP imaging alone, but the discovery of additional lesions did not affect the management of any of the patients in this study.     

Hepatic perfusion changes in mice livers with developing colorectal cancer metastases

PURPOSE: To evaluate whether intrahepatic flow alterations occur during formation of hepatic colorectal cancer metastases and to identify possible causes of these alterations. MATERIALS AND METHODS: Intravital imaging of exteriorized livers was performed in 72 live mice. Three groups of mice were studied: a sham-operated control group (n = 24), a group with nonmetastasizing subcutaneous gliomas (n = 24), and a group with developing hepatic CX-1 colon cancer metastases (n = 24). Microvascular flow parameters, leukocyte-endothelial interactions, and wall shear stress were directly measured in hepatic sinusoids and postsinusoidal venules at 2-day intervals prior to and during the development of metastases. The Kruskal-Wallis test was used initially to test for overall equality of medians in each data group. Single posttest comparisons of independent samples were performed with the Mann-Whitney test, with an overall statistical significance of .05. RESULTS: Prior to the development of visible colorectal cancer metastases, significant (P <.05) reductions occurred in sinusoidal and postsinusoidal flow and wall shear rates, coupled with increased leukocyte rolling and adherence. With tumor growth, flow was further compromised in 92% of tumors larger than 0.5 mm in diameter by extrinsic compression of sinusoids and portal venules and narrowing caused by adherent leukocytes. CONCLUSION: Significant intrahepatic flow alterations occur in mouse livers prior to growth of visible metastases and provide a rational explanation for elevation in the Doppler perfusion index that occurs prior to tumor formation.     

Hepatic metastases studied with MR and CT

Examinations of the liver using magnetic resonance (MR) and computed tomography (CT) were performed on 50 patients with hepatic metastases. MR and CT were comparable in their ability to detect metastases, which generally appeared hypointense compared with normal liver parenchyma on T1-weighted MR images and hyperintense on T2-weighted images. The MR imaging techniques that were most reliable in detecting metastases were inversion recovery and a relatively T2-weighted, spin-echo technique (TR = 1,500 msec, TE = 60 msec). We conclude that CT, because of its shorter imaging time, greater spatial resolution, and lower cost, should remain the preferred screening test for hepatic metastases. MR imaging should be reserved for patients with equivocal CT findings and for patients in whom there is persistent clinical suspicion of hepatic metastases despite a negative CT examination.