Small (≤ 2 cm) Hepatic Lesions in Colorectal Cancer Patients:Detection and Characterization on Mangafodipir Trisodium–Enhanced MRI

The value of preoperative computed tomography combined with ultrasound in the investigation of small indeterminate liver lesions in patients with colorectal cancer

Background Computed tomography (CT) is used routinely for the preoperative detection of colorectal cancer (CRC) metastases. When small indeterminate focal liver lesions are detected that are too small to characterize (TSTC) on CT, additional imaging is usually needed, resulting in a potential delay in obtaining a complete diagnostic work-up. Purpose To determine the diagnostic accuracy of ultrasound (US) of the liver performed in direct conjunction to CT in the preoperative investigation among patients with newly diagnosed CRC when indeterminate liver lesions were found on CT. Material and Methods Preoperative investigations with CT and consecutive US where CT had shown at least one focal liver lesion in 74 patients diagnosed with CRC between June 2009 and February 2012 were retrospectively reviewed. Either histopathological findings or a combination of imaging and clinical follow-up one to three years after surgery was used as the reference. Results Liver metastases were diagnosed with CT/US in 13 out of 74 patients (17.6%). In one patient, a liver cyst was preoperatively regarded as liver metastasis by a combined CT/US. The sensitivity and specificity for the CT with consecutive US procedure was 100% (13/13) and 98.4% (60/61). Conclusion US performed in conjunction with CT in patients with indeterminate focal liver lesions on CT is an accurate work-up for detection of liver metastases in patients with newly diagnosed CRC. Although our results are promising, they cannot be considered safely generalizable to all hospitals.

The impact of PET/CT on the management of hepatic and extra hepatic metastases from gastrointestinal cancers

PURPOSE

To investigate the efficacy of positron emission tomography/computed tomography (PET/CT) in detection and management of hepatic and extrahepatic metastases from gastrointestinal cancers.

MATERIALS AND METHODS

Between February 2008 and July 2010, patients histopathologically diagnosed with gastrointestinal cancer and showing suspected metastasis on CT screening were subsequently evaluated with PET/CT. All patients were subgrouped according to histopathological origin and localization of the primary tumor. Localization of gastrointestinal cancers was further specified as lower gastrointestinal system (GIS), upper GIS, or hepato-pancreato-biliary (HPB). Both accuracy and impact of CT and PET/CT on patient management were retrospectively evaluated.

RESULTS

One hundred and thirteen patients diagnosed histopathologically with gastrointestinal cancers were retrospectively evaluated. Seventy-nine patients had adenocarcinoma and 34 patients other gastrointestinal tumors. Forty-one patients were in the upper GIS group, 30 patients in the HPB group, and 42 patients in the lower GIS group. Evaluation the diagnostic performance of PET/CT for suspected metastasis according to histopathological origin of the tumor, revealed that the sensitivity of PET/CT - although statistically not different - was higher in adenocarcinomas than in non-adenocarcinomas (90% (95% CI, 0.78-0.96) vs. 71.4% (95% CI, 0.45-0.88), P=0.86). The specificity was not significantly different (85.7% (95% CI, 0.70-0.93) vs. 85% (95% CI, 0.63-0.94), P=1.00). In the overall patient group; CT was significantly more sensitive than PET/CT for detection of hepatic metastases (94.7% vs. 78.9%, P=0.042), whereas PET/CT was significantly more specific than CT (48% vs. 98.7%, P<0.001). In subgroup analysis, sensitivity was not significantly different (P>0.05) but specificity was significantly higher in PET/CT than CT (P<0.05). The specificity of PET/CT was highest in upper GIS (100%) and HPB (100%) subgroups. In the overall patient group; for detection of extrahepatic metastasis, the sensitivity of CT (75%) and PET/CT (87.5%) showed no significant difference (P=0.437). However, PET/CT was significantly more specific than CT (88.7% vs. 70.4%, P=0.007). In subgroup analysis, no significant difference was found between CT and PET/CT either in sensitivity or in specificity (P>0.05). The specificity of PET/CT was highest in the lower GIS subgroup (93%). The management of 45 patients (39.8%) was revised after PET/CT evaluation.

CONCLUSIONS

PET/CT has a higher specificity than CT in detecting suspected hepatic and extrahepatic metastases of gastrointestinal cancers, and has an impact of nearly 40% on changing patient management strategies.

Added value of arterial enhancement fraction color maps for the characterization of small hepatic low-attenuating lesions in patients with colorectal cancer

OBJECTIVE

To assess the added value of arterial enhancement fraction (AEF) color maps for the differentiation of small metastases from hepatic benign lesions.

SUBJECTS AND METHODS

We retrospectively analyzed 46 patients with colorectal cancer who underwent multiphasic liver CT imaging and had low-attenuating liver lesions smaller than 3 cm (123 total lesions; metastasis: benign = 32:91). AEF color maps of the liver were created from multiphasic liver CT images using dedicated software. Two radiologists independently reviewed multiphasic CT image sets alone and in combination with image sets with AEF color maps using a five-point scale. The additional diagnostic value of the color maps was assessed by means of receiver-operating characteristic (ROC) analysis.

RESULTS

The area under the ROC curve (Az) increased when multiphasic CT images were combined with AEF color map analysis as compared with evaluation based only on multiphasic CT images (from 0.698 to 0.897 for reader 1, and from 0.825 to 0.945 for reader 2; P < 0.001 and 0.002, respectively). The increase Az was especially significant for lesions less than 1 cm (from 0.702 to 0.888 for reader 1, and from 0.768 to 0.958 for reader 2; P = 0.001 and P = 0.001, respectively). The mean AEF of tumor-adjacent parenchyma (35.07 ± 27.2) was significantly higher than that of tumor-free liver parenchyma (27.3 ± 20.6) (P = 0.04).

CONCLUSIONS

AEF color mapping can improve the diagnostic performance for small hepatic metastases from colorectal cancer and may allow for the elimination of additional examinations.

A retrieval-based computer-aided diagnosis system for the characterization of liver lesions in CT scans

RATIONALE AND OBJECTIVES

To evaluate a computer-aided diagnosis (CADx) system for the characterization of liver lesions in computed tomography (CT) scans. The stand-alone predictive performance of the CADx system was assessed and compared to that of three radiologists who were provided with the same amount of image information to which the CADx system had access.

MATERIALS AND METHODS

The CADx system operates as an image search engine exploiting texture analysis of liver lesion image data for the lesion in question and lesions from a database. A region of interest drawn around an indeterminate liver lesion is used as input query. The CADx system retrieves lesions of similar histology (benign/malignant), density (hypodense/hyperdense), or type (cyst/hemangioma/metastasis). The system's performance was evaluated with leave-one-patient-out receiver operating characteristic area under the curve on 685 CT scans from 372 patients that contained 2325 liver lesions (193 <1 cm(3)). Sensitivity, specificity, and positive and negative predictive values were evaluated separately for subcentimeter lesions. Results were compared to those of three radiologists who rated 83 liver lesions (20 hemangiomas, 20 metastases, 20 cysts, 20 hepatocellular carcinomas, and 3 focal nodular hyperplasias) displaying only the liver.

RESULTS

The CADx system's leave-one-patient-out receiver operating characteristic area under the curve was 97.1% for density, 91.4% for histology, and 95.5% for lesion type. For subcentimeter lesions, input of additional semantic information improved the system's performance. The CADx system has been proved to significantly outperform radiologists in discriminating lesion histology and type, provided the radiologists have no access to information other than the image. The radiologists were most reliable in diagnosing hemangioma given the limited image data.

CONCLUSIONS

The CADx system under study discriminated reliably between various liver lesions, even outperforming radiologists when accessing the same image information and demonstrated promising performance in classifying subcentimeter lesions in particular.

Diagnostic efficacy of gadoxetic acid-enhanced MRI for the detection and characterisation of liver metastases: comparison with multidetector-row CT

OBJECTIVES

We compared the diagnostic performance of gadoxetic acid-enhanced MRI and 16-slice multidetector CT (MDCT) with respect to their abilities to detect hepatic metastases and differentiate hepatic metastases from hepatic cysts and haemangiomas.

METHODS

67 patients with 110 liver metastases (size 0.3-2.5 cm), 33 haemangiomas (size 0.5-1.5 cm) and 17 cysts (size 0.3-1.0 cm) underwent 4-phase MDCT and gadoxetic acid-enhanced MRI, including early dynamic phases, post-contrast T(2) weighted turbo spin echo sequences and 20 min hepatocyte-selective phases. Two observers independently analysed each image in random order. Sensitivity and diagnostic accuracy for lesion detection and differentiation for MDCT and gadoxetic acid-enhanced MRI were calculated using receiver operating characteristic analysis.

RESULTS

For both observers, the Az values of gadoxetic acid-enhanced MRI (mean, 0.982 and 0.981) were significantly higher than the Az values of MDCT (mean, 0.839 and 0.892) (p<0.05) for the detection of metastases and for the differentiation of metastases from haemangiomas and cysts. Sensitivities of gadoxetic acid-enhanced MRI with regard to the detection and characterisation of liver metastases (mean, 96.9% and 96.0%) were significantly higher than those of MDCT (mean, 78.7% and 75.0%) (p<0.05).

CONCLUSION

Gadoxetic acid-enhanced MRI showed higher diagnostic accuracy and sensitivity than did MDCT for the detection of hepatic metastases and for the differentiation between hepatic metastases and hepatic haemangiomas or cysts.

Combining diffusion-weighted MRI with Gd-EOB-DTPA-enhanced MRI improves the detection of colorectal liver metastases

OBJECTIVES

To compare the diagnostic accuracy of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI, diffusion-weighted MRI (DW-MRI) and a combination of both techniques for the detection of colorectal hepatic metastases.

METHODS

72 patients with suspected colorectal liver metastases underwent Gd-EOB-DTPA MRI and DW-MRI. Images were retrospectively reviewed with unenhanced T(1) and T(2) weighted images as Gd-EOB-DTPA image set, DW-MRI image set and combined image set by two independent radiologists. Each lesion detected was scored for size, location and likelihood of metastasis, and compared with surgery and follow-up imaging. Diagnostic accuracy was compared using receiver operating characteristics and interobserver agreement by kappa statistics.

RESULTS

417 lesions (310 metastases, 107 benign) were found in 72 patients. For both readers, diagnostic accuracy using the combined image set was higher [area under the curve (Az)=0.96, 0.97] than Gd-EOB-DTPA image set (Az=0.86, 0.89) or DW-MRI image set (Az=0.93, 0.92). Using combined image set improved identification of liver metastases compared with Gd-EOB-DTPA image set (p<0.001) or DW-MRI image set (p<0.001). There was very good interobserver agreement for lesion classification (κ=0.81-0.88).

CONCLUSIONS

Combining DW-MRI with Gd-EOB-DTPA-enhanced T(1) weighted MRI significantly improved the detection of colorectal liver metastases.

Real-time ultrasonography-computed tomography fusion imaging for staging of hepatic metastatic involvement in patients with colorectal cancer: initial results from comparison to US seeing separate CT images and to multidetector-row CT alone

OBJECTIVES

To prospectively evaluate the role of real-time ultrasonography (US)-computed tomography (CT) fusion imaging (US-CT) in comparison with US seeing separate CT images (US + CT) and multidetector-row CT (MDCT) for the correct staging of hepatic metastatic involvement in patients with colorectal cancer.

METHODS

Sixty-four patients with newly diagnosed colorectal cancer and who were referred for abdominopelvic staging before primary tumor resection underwent same-day MDCT, US + CT, and US-CT. Examinations were evaluated on-site by 2 investigators in consensus. Investigators recorded the size and location of detected lesions on segmental liver maps, classified them as being benign, malignant, or indeterminate, and finally assessed the M stage of the liver as being M0, M1, or Mx (indeterminate). All patients underwent surgical exploration including intraoperative US. Reference standard diagnosis was based on findings at surgery, intraoperative US, histopathology, and MDCT follow-up imaging. Differences among investigated modalities were analyzed using McNemar's test.

RESULTS

The reference standard verified 109 (45 < or = 1 cm) hepatic lesions in 25 patients, including 65 (25 < or = 1 cm) metastases in 16 patients (M1). Regarding the 45 < or = 1 cm liver lesions, rates for detection were significantly higher (P < 0.05) for MDCT (80%, 36/45) and US-CT (77.8%, 35/45) than for US + CT (64.4%, 29/45); the rate for correct classification by US-CT (71.1%, 32/45) was significantly higher than for US + CT (48.9%, 22/45) and MDCT (31.1%, 14/45) (all P < 0.05). On patient-based analysis, specificity of MDCT (85.4%, 41/48) was significantly lower (P < 0.05) than for US-CT (97.9%, 47/48) and US + CT (93.7%, 45/48); the positive predictive value of MDCT (63.1%, 12/19) was not significantly different (P = 0.27) compared with US + CT (82.3%, 14/17) but significantly lower (P < 0.05) than for US-CT (93.7%, 15/16). In 13 patients (59 lesions) with only benign (stage M0) or coexistent benign and malignant lesions (stage M1), indeterminate lesion ratings and indeterminate liver stagings (Mx) occurred both significantly lower (P < 0.05) with US-CT (3.4%, 2/59; and 0%, 0/13) than with US + CT (11.9%, 7/59; and 23.1%, 3/13) or with MDCT (30.5%, 18/59; and 53.8%, 7/13).

CONCLUSIONS

Based on these initial diagnostic experiences, complementary US-CT fusion imaging of small CT-indeterminate liver lesions may have value in staging patients with colorectal cancer, focusing on patients who were likely to harbor only benign or coexisting benign and malignant liver lesions and in whom change of M staging would change the clinical management.

Appearances of colorectal hepatic metastases at diffusion-weighted MRI compared with histopathology: initial observations

OBJECTIVE

To describe the appearances of colorectal liver metastases on diffusion-weighted MRI (DW-MRI) and to compare these appearances with histopathology.

METHODS

43 patients with colorectal liver metastases were evaluated using breath-hold DW-MRI (b-values 0, 150 and 500 s mm(-2)). The b=500 s mm(-2) DW-MRI were reviewed consensually for lesion size and appearance by two readers. 18/43 patients underwent surgery allowing radiological-pathological comparison. Tissue sections were reviewed by a pathologist, who classified metastases histologically as cellular, fibrotic, necrotic or mixed. The frequency of DW-MRI findings and histological features were compared using the χ(2) test.

RESULTS

84 metastases were found in 43 patients. On b=500 s mm(-2) DW-MRI, metastases showed three high signal intensity patterns: rim (55/84), uniform (23/84) and variegate (6/84). Of the 55 metastases showing rim pattern, 54 were >1 cm in diameter (p<0.01, χ(2) test). 25/84 metastases were surgically resected. Of these, 11/22 metastases >1 cm in diameter showed rim pattern and demonstrated central necrosis at histopathology (p=0.04, χ(2) test). No definite relationship was found between uniform and variegate patterns with histology.

CONCLUSION

Rim high signal intensity was the most common appearance of colorectal liver metastases >1 cm diameter on DW-MRI at b-values of 500 s mm(-2), a finding attributable to central necrosis.

Preoperative detection of colorectal liver metastases in fatty liver: MDCT or MRI?

OBJECTIVE

To compare the diagnostic value of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative detection of colorectal liver metastases in diffuse fatty infiltration of the liver, associated with neoadjuvant chemotherapy.

MATERIALS AND METHODS

Twenty preoperative tri-phasic MDCT (4-64-row, Siemens) and dynamic contrast-enhanced MRI (1.5T or 3.0T, Siemens) examinations of patients with colorectal cancer and liver metastases in diffuse steatosis were retrospectively evaluated. All patients underwent surgical resection for liver metastases (time interval 1-60 days). The amount of fatty infiltration of the liver was determined histopathologically by semi-quantitative percent-wise estimation and ranged from 25 to 75%.

RESULTS

Overall, 51 metastases were found by histopathology of the resected liver segments/lobes. The size of the metastases ranged from 0.4 to 13 cm, with 18 (35%) being up to 1cm in diameter. In the overall rating, MDCT detected 33/51 lesions (65%), and MRI 45/51 (88%). For lesions up to 1cm, MDCT detected only 2/18 (11%) and MRI 12/18 (66%). One false positive lesion was detected by MDCT. Statistical analysis showed that MRI is markedly superior to MDCT, with a statistically significant difference (p<.001), particularly for the detection of small lesions (≤ 1 cm; p<.004). There was no significant difference between the two modalities in the detection of lesions>1cm.

CONCLUSION

For the detection of colorectal liver metastases after neoadjuvant chemotherapy and consecutive diffuse fatty infiltration of the liver, MRI is superior to MDCT, especially for the detection of small lesions.

Contrast-enhanced intraoperative ultrasound improves detection of liver metastases during surgery for primary colorectal cancer

BACKGROUND

Computed tomography (CT) is the most common staging investigation in colorectal cancer (CRC). Up to 25% of patients are found to have previously undetected hepatic lesions when intraoperative ultrasound (IOUS) of the liver is used during CRC resection. We aimed to assess the ability of IOUS to detect additional liver lesions/metastases at primary colorectal resection, and to evaluate whether contrast-enhanced IOUS (CE-IOUS) improves the detection and characterization of hepatic lesions.

METHODS

We performed a single-centre, prospective pilot study. At CRC resection, patients underwent IOUS of the liver. Contrast-enhanced IOUS of the liver was undertaken using i.v. sulphur hexafluoride micro-bubbles (SonoVue, 4.8 ml). Findings of CT, non-enhanced IOUS and CE-IOUS were compared. Changes in staging or management were noted. Additional lesions were corroborated with iron oxide magnetic resonance imaging (MRI).

RESULTS

Among 21 patients, IOUS demonstrated additional lesions in seven (33%). Contrast altered the diagnosis of non-enhanced IOUS in four (20%) and changed the management strategy in three (14%) patients. Thus, IOUS in combination with the contrast agent altered the intraoperative or postoperative management plan in four patients.

CONCLUSIONS

In the first study of its kind, early results suggest that the ability of IOUS to detect additional metastases is improved by CE-IOUS, and that this may impact on surgical staging and management.

Performance of imaging modalities in diagnosis of liver metastases from colorectal cancer: a systematic review and meta-analysis

Surgery of liver metastases can be effective, and the appropriate selection of surgical candidates relies first on imaging. Different techniques are available, but information on their relative performance is unclear. The aim of this overview is to assess the imaging modality performance in the diagnosis of colorectal cancer (CRC) liver metastases. MEDLINE and EMBASE were searched for articles published from January 2000 to August 2008. Eligible trials had to be conducted on patients with diagnosis/suspicion of CRC liver metastases, comparing more than two modalities among MRI, computed tomography (CT), positron emission tomography using fluoro-18-deoxyglucose (FDG-PET), ultrasonography (US). Pooled estimates of sensitivity, specificity were calculated and pair-wise comparisons were performed. Of 6030 screened articles, 25 were eligible. Sensitivity and specificity on a per-patient basis for US, CT, MRI, and FDG-PET were 63.0% and 97.6%, 74.8% and 95.6%, 81.1% and 97.2, and 93.8% and 98.7%, respectively. On a per-lesion basis, sensitivity was 86.3%, 82.6%, 86.3%, and 86.0%, respectively. Specificity was reported in few studies. MRI showed a better sensitivity than CT in per-patient (odds ratio [OR]: 0.69; 95% confidence interval [CI]: 0.47-0.99; P = 0.05) and in per-lesion analysis (OR: 0.66; 95% CI: 0.55-0.80; P < 0.0001). In per-lesion analysis, the difference was higher when liver-specific contrast agents were administered. Available evidence supports the MRI use for the detection of CRC liver metastases.

Diffusion-weighted MR imaging of the liver

Magnetic resonance (MR) imaging plays an increasingly important role in the evaluation of patients with liver disease because of its high contrast resolution, lack of ionizing radiation, and the possibility of performing functional imaging sequences. With advances in hardware and coil systems, diffusion-weighted (DW) MR imaging can now be applied to liver imaging with improved image quality. DW MR imaging enables qualitative and quantitative assessment of tissue diffusivity (apparent diffusion coefficient) without the use of gadolinium chelates, which makes it a highly attractive technique, particularly in patients with severe renal dysfunction at risk for nephrogenic systemic fibrosis. In this review, acquisition parameters, postprocessing, and quantification methods applied to liver DW MR imaging will be discussed. The current clinical uses of DW MR imaging (liver lesion detection and characterization, compared and combined with conventional sequences) and the emerging applications of DW MR imaging (tumor treatment response and diagnosis of liver fibrosis and cirrhosis) will be reviewed. Also, limitations, mainly image quality and reproducibility of diffusion parameters, and future directions of liver DW MR imaging will be discussed.

Natural history of small, "indeterminate" hepatic lesions in patients with colorectal cancer

PURPOSE

The initial staging CT scan for patients with colorectal cancer may reveal small, "indeterminate" hepatic lesions. The significance of these lesions is often unknown at the time of diagnosis. Surveillance of these lesions is often recommended because they may have an impact on the subsequent management of these patients. This study was designed to determine the prevalence and significance of small (<1 cm on CT scan), indeterminate liver lesions detected preoperatively in patients with colorectal cancer and to determine whether further surveillance imaging of these patients is required.

METHODS

Data were collected retrospectively, from January 1, 2002, to December 31, 2005. All colorectal cancer patients with small, indeterminate liver lesions on their initial staging CT scan were included. These lesions were formally reported as being too small to be characterized. All subsequent surveillance images of the liver were reviewed to assess the natural history of these lesions.

RESULTS

Four hundred nineteen patients with colorectal cancer had staging CT performed. Seventy patients (16.7%) had small liver lesions on their initial CT that could not be definitely characterized. Forty-six (65.7%) underwent subsequent imaging of their liver lesions. Forty-one (89.1%) of these were shown to be stable lesions that were likely benign. Only five patients (10.9%) showed progression on subsequent liver imaging, suggestive of early metastases and consistent with their clinical picture.

CONCLUSION

Small, indeterminate liver lesions may occur in up to 16.7% of patients with colorectal cancer. Although most of these lesions remain quiescent, surveillance imaging is recommended because a small but not insignificant proportion of patients with such lesions actually harbor early metastases.

Dangerous halo after neoadjuvant chemotherapy and two-step hepatectomy for colorectal liver metastases

BACKGROUND

Bilobar colorectal metastases are a therapeutic challenge and require a multidisciplinary approach. The aim of this study was to describe the clinical and histological outcomes of patients having neoadjuvant chemotherapy and two-step hepatectomy with right portal vein occlusion for advanced bilateral colorectal metastases.

METHODS

A series of 23 consecutive patients treated with curative intent according to a standardized multidisciplinary management protocol was reviewed.

RESULTS

Of 23 patients, 22 completed the programme. There was no mortality and no Clavien grade III morbidity. Median survival from the start of treatment was 45 months, and 1-, 3- and 5-year Kaplan-Meier estimates were 95, 73 and 27 per cent respectively. On histology at the first operation, ten patients had a dangerous halo of proliferating tumour cells infiltrating the surrounding liver parenchyma, of variable importance (six focal and four diffuse), regardless of the response to chemotherapy of the metastases. The dangerous halo increased in prevalence and importance (six focal and seven diffuse) between the first and second operation.

CONCLUSION

Neoadjuvant chemotherapy followed by two-step hepatectomy with right portal vein occlusion is feasible, safe and may be advantageous to the patient. The appearance of a dangerous halo around the liver metastases may require adaptation of the surgical technique to decrease the risk of local recurrence.

Diferenciação entre cisto simples e hemangioma hepático utilizando seqüência de ressonância magnética ponderada em T2 com técnica gradiente-eco (B-FFE)

OBJETIVO: Estabelecer o valor das seqüências ponderadas em T2 para diferenciar cistos simples de hemangiomas hepáticos. MATERIAIS E MÉTODOS: Estudo prospectivo, observacional, transversal e duplo-cego em 52 pacientes com 91 lesões hepáticas (34 cistos simples e 57 hemangiomas) submetidos a ressonância magnética de abdome. A análise conjunta de todas as seqüências realizadas foi considerada o padrão-ouro. Dois observadores independentes avaliaram, subjetivamente, as seqüências TSE com TE longo e B-FFE, procurando diferenciar cistos de hemangiomas. Foram calculadas a eficácia das seqüências e a concordância interobservador e intra-observador por meio do teste kappa (κ) (p < 0,05*). RESULTADOS: As dimensões dos cistos variaram entre 0,5 e 6,5 cm (média de 1,89 cm) e as dos hemangiomas, entre 0,8 e 11 cm (média de 2,62 cm). A concordância entre a avaliação da seqüência com TE longo e o padrão-ouro foi insignificante (κ: 0,00-0,10). A concordância entre a avaliação da seqüência B-FFE e o padrão-ouro variou de substancial (κ: 0,62-0,71) a quase perfeita (κ: 0,86) para ambos os examinadores. A concordância interobservador e intra-observador para a seqüência B-FFE variou entre substancial (κ: 0,62-0,70) e quase perfeita (κ: 0,85-0,91). CONCLUSÃO: A técnica B-FFE apresenta eficácia e reprodutibilidade elevadas na diferenciação de cistos e hemangiomas.

Advances in radiological imaging of gastrointestinal tumors

This article summarizes the recent advances in radiological imaging in the hepatogastrointestinal field in terms of detection, characterization and staging of tumors. Introduction of multidetector row computed tomography technology has helped computed tomography to excel in its already established indications, and has expanded its capabilities by adding new clinical applications, such as computed tomography angiography, liver perfusion, computed tomography enterography or enteroclysis, and virtual colonoscopy. Contrast-enhanced ultrasound has dramatically changed the role of ultrasound in liver tumor characterization, detection, and other applications. Combining the advantages of unsurpassed soft tissue contrast and lack of ionizing radiation, magnetic resonance imaging of the gastrointestinal tract has become increasingly used clinically. Moreover, substantial progress in molecular and cellular magnetic resonance imaging has been achieved in the past few years. Particularly, the increasing number of available specific contrast agents dedicated to the evaluation of the liver and lymph nodes shows promises in the area of oncologic abdominal imaging.

Preoperative imaging for metastasectomy

For most solid neoplasms, medical imaging is a vital component of tumor staging and surveillance. Imaging strategies vary according to the type and grade of primary neoplasm, tumor stage at diagnosis, tumor markers, previous therapies, and patient symptoms. In this article, we address imaging of individual organs (lung, liver, adrenals) and outline imaging strategies for specific types of neoplasms.

Detection of colorectal hepatic metastases using MnDPDP MR imaging and diffusion-weighted imaging (DWI) alone and in combination

To compare the diagnostic accuracy of MnDPDP MR imaging and diffusion-weighted imaging (DWI), alone and in combination, for detecting colorectal liver metastases in patients with suspected metastatic disease. Thirty-three consecutive patients with suspected colorectal liver metastases underwent MR imaging. Three image sets (MnDPDP, DWI and combined MnDPDP and DWI) were reviewed independently by two observers. Lesions were scored on a five-point scale for malignancy and the areas (Az) under the receiver operating characteristic curves were calculated for each observer and image set. The sensitivity and specificity for lesion detection were calculated for each image set and compared. There were 83 metastases, 49 cysts and 1 haemangioma. Using the combined set resulted in the highest diagnostic accuracy for both observers (Az=0.94 and 0.96), with improved averaged sensitivity of lesion detection compared with the DWI set (p=0.01), and a trend towards improved sensitivity compared with the MnDPDP set (p=0.06). There was no difference in the averaged specificity using any of the three image sets (p>0.5). Combination of MnDPDP MR imaging and DWI resulted in the highest diagnostic accuracy and can increase sensitivity without loss in specificity.

Metachronous liver metastases and resectability: Fong's score and laparoscopic evaluation

BACKGROUND AND AIMS

The aim of this retrospective study was to establish whether Fong's risk score can predict rate of resectability and whether laparoscopic exploration with ultrasonography can reduce the number of useless laparotomies to any extent.

MATERIAL AND METHODS

Fong's score was calculated for each of the 43 potential resectable patients. We analysed: the relation between score and resectability; the probability of unnecessary laparotomy with respect to each level of score; and which of the five Fong parameters was the most indicative of non-resectability. None of our patients was submitted to preoperative laparoscopic staging.

RESULTS

All patients with Fong's score 0 were submitted to liver resection, whereas only 76.9% with score 1, 58.3% with score 2, and 66.6% with score 3. No patients had score 4 and 5. "CEA level" is the parameter that best predicts the "non-resectability" of metastases. In the subgroup with score 0-1, laparoscopy would have spared 12% of unnecessary laparotomies, whereas in subgroup 2-3 this percentage would have risen to 38.9.

CONCLUSIONS

The above data allowed us to quantify statistically the risk associated with non-resectability of liver metastases in a directly proportional manner as the score progresses.

Can contrast-enhanced ultrasonography replace multidetector-computed tomography in the detection of liver metastases from colorectal cancer?

PURPOSE

To compare the sensitivity and specificity of contrast-enhanced ultrasonography (CEUS) and 4-slice multidetector-computed tomography (MDCT) in the detection of liver metastases in patients with colorectal cancer (CRC).

MATERIALS AND METHODS

Candidates for this prospective study were 461 consecutive patients referred to the Department of Colorectal Surgery, Aarhus University Hospital with primary or local recurrence of CRC. The patients underwent liver ultrasonography (US), CEUS, MDCT and intraoperative ultrasonography (IOUS). Fine-needle biopsy was performed on all suspicious lesions. The examinations were interpreted blindly and the combination of US, CEUS, biphasic MDCT, IOUS, follow up and biopsy was the gold standard.

RESULTS

Three hundred and sixty-five patients were included. All patients had undergone preoperative US, CEUS and MDCT and 65.5% had received IOUS. The gold standard found liver metastases in 54 patients (14.8%). Multidetector CT found significantly more metastases than CEUS in 15 (28%) of the patients (p=0.02). In a patient-by-patient analysis MDCT had a non-significantly higher sensitivity in the detection of liver metastases compared to CEUS (0.89 versus 0.80, p=0.06). The specificity of CEUS (0.98) was slightly better than that of MDCT (0.94) (p=0.02).

CONCLUSION

Multidetector CT found significant more metastases than CEUS, and MDCT had in patient-by-patient analysis a non-significant better sensitivity (p=0.06) in detecting liver metastases in patients with CRC.

[Radiological diagnosis of hepatic tumors. Part II: Identification and differential diagnosis]

Focal hepatic lesions occur in 5% of the population. The clarification of such common occurrences is of major significance because oncological diseases play an important role with respect to morbidity and mortality of the population. The first part of this review article dealt with the most important aspects of classification, epidemiology and pathology of hepatic tumors for radiologists and the current technical situation with regards to the diagnostic procedure. This second part of the review deals with the significance of radiological procedures for identification and differential diagnosis of hepatic tumors.

Imaging to optimally stage lung cancer: conventional modalities and PET/CT

Accurately staging patients with lung cancer is important in determining treatment options and prognoses. Staging allows the distinction of patients who are candidates for surgical resection from those with inoperable disease who may be treated with chemotherapy and/or radiation therapy. Conventional imaging plays an essential role in the noninvasive and invasive methods of the evaluation and staging of patients with non-small-cell lung cancer (NSCLC). Imaging modalities used for staging include chest radiography, chest computed tomography (CT), abdominal CT, brain CT or magnetic resonance imaging, bone scans, and (18)F-2-deoxy-d-glucose positron emission tomography (PET). Recently, PET/CT, the integration of the functional data of PET with the anatomic data of CT, has emerged as a modality to potentially change the way patients are evaluated. This article reviews current recommendations regarding the staging of patients with NSCLC and addresses the role of PET/CT.

Lésions hépatiques en cancérologie générale

In order to improve management of oncologic patients, a standardized 5-step approach should be considered: detection, characterization, locoregional and systemic staging, and post treatment follow up. The use of imaging techniques will be adapted to the clinical question at hand during multi-disciplinary review of cases. The role of the radiologist is to review the indications for each imaging modality and incorporate the results in the clinical context.

Hepatobiliary MRI: current concepts and controversies

Evaluation of the liver and biliary system is a frequent indication for abdominal MRI. Hepatobiliary MRI comprises a set of noninvasive techniques that are usually very effective in answering most clinical questions. There are significant limitations, however, as well as considerable variation and disagreement regarding the optimal protocols for standard hepatic MRI and magnetic resonance cholangiopancreaticography (MRCP). This review discusses pulse sequences most often used in hepatic MRI and MRCP, examines a few sources of controversy in the current literature, and summarizes some recent and future developments in the field.

Diagnostic accuracy of rim and segmental MRI enhancement of colorectal hepatic metastasis after administration of mangafodipir trisodium

OBJECTIVE

The purpose of this study was to determine the diagnostic accuracy of rim and segmental MRI enhancement of hepatic metastasis of colorectal cancer after administration of mangafodipir trisodium (MnDPDP).

SUBJECTS AND METHODS

Sixty-one patients with a potentially resectable hepatic metastasis of colorectal cancer consecutively underwent breath-hold T1-weighted MRI in the axial and coronal planes 30 minutes and 24 hours after administration of MnDPDP. For each lesion, the presence or absence of rim enhancement and segmental enhancement 30 minutes and 24 hours after contrast administration was recorded. These features were evaluated separately for lesions 10 mm in diameter or larger and lesions smaller than 10 mm. The nature of each lesion was determined at histopathologic examination (n = 29) and on follow-up imaging (n = 32).

RESULTS

Two hundred thirty lesions were identified at MRI: 210 lesions were metastatic, and 20 were benign. Rim enhancement was observed around 22 of 210 (10%) of the metastatic lesions at 30 minutes and 199 of 210 (95%) of metastatic lesions at 24 hours. Rim enhancement at 24 hours had 94.8% (95% CI, 91.8-97.8%) sensitivity, 90.0% (68.3-98.8%) specificity, 99.0% (97.6-100%) positive predictive value, 62.1% (42.3-79.3%) negative predictive value, and 94.3% (91.4-97.3%) diagnostic accuracy for metastasis. Segmental enhancement was infrequently seen (34/210; 16%) at 24 hours but had 100% (89.7-100%) positive predictive value for metastasis.

CONCLUSION

Rim and segmental enhancement at MRI 24 hours after MnDPDP administration enabled accurate characterization of hepatic colorectal metastasis. These features may aid in preoperative mapping of hepatic tumor burden and disease distribution in patients with colorectal cancer.

Detection of hepatic metastasis: manganese- and ferucarbotran-enhanced MR imaging

PURPOSE

To compare the mangafodipir trisodium (MnDPDP)-enhanced and ferucarbotran-enhanced magnetic resonance imaging (MRI) for the detection of hepatic metastases.

MATERIAL AND METHODS

Twenty patients with known hepatic metastasis underwent MR imaging using mangafodipir trisodium and ferucarbotran in at least 1-day intervals. Thirty-eight metastases were confirmed either histologically or clinically. Two radiologists independently reviewed the MnDPDP-enhanced and ferucarbotran-enhanced sets in a random order. The sensitivity and accuracy of lesion detection and the ability to distinguish a benign lesion from a malignant lesion were compared by the areas (Az) under the receiver operating characteristic (ROC) curve. The lesion-liver contrast-to-noise ratios (CNR) were compared by paired t-test.

RESULTS

The overall accuracy for detecting metastases was not significantly different between the MnDPDP set (Az=0.912 and 0.913 for reader 1 and 2, respectively) and the SPIO set (Az=0.920 and 0.950). The CNR at the MnDPDP-enhanced images and the SPIO-enhanced images were not significantly different (P=0.146).

CONCLUSION

Both MnDPDP- and ferucarbotran-enhanced MRI have a comparable accuracy in detecting hepatic metastasis.

Comparison of mangafodipir trisodium- and ferucarbotran-enhanced MRI for detection and characterization of hepatic metastases in colorectal cancer patients

OBJECTIVE

The purpose of our study was to evaluate the validity of mangafodipir trisodium-enhanced versus ferucarbotran-enhanced MRI in the detection and characterization of hepatic lesions in colorectal cancer patients.

MATERIALS AND METHODS

Forty-one patients who were known to have or suspected of having hepatic metastasis from colorectal carcinoma underwent mangafodipir trisodium- or ferucarbotran-enhanced MRI in block randomization methods. Two radiologists independently reviewed the MR images to determine the number of hepatic lesions and to characterize the lesions as malignant or benign. Each lesion was assessed according to its size (small, <or= 2 cm; large, > 2 cm in diameter) on both mangafodipir trisodium- or ferucarbotran-enhanced MRI. The data were correlated with the reference diagnosis: histopathology and intraoperative sonography (n = 16); intraoperative sonography (n = 4); and imaging and clinical diagnosis with follow-up (> 3 months; n = 21). The detection rates and diagnostic accuracies of hepatic lesions on both sets of MR images were assessed using Fisher's exact test.

RESULTS

Eighty-two hepatic lesions (53 metastatic and 29 benign) were identified in 41 patients. No significant differences were seen between mangafodipir trisodium- and ferucarbotran-enhanced MRI for detecting all hepatic lesions (p = 0.183), small hepatic lesions (p = 0.299), all metastases (p = 0.695), and small metastases (p = 0.689). The diagnostic accuracies of mangafodipir trisodium- and ferucarbotran-enhanced MRI showed no significant differences in all hepatic lesions (p = 0.624) and small hepatic lesions (p = 0.641).

CONCLUSION

Mangafodipir trisodium- and ferucarbotran-enhanced MRI are similar in hepatic lesion detection and characterization in colorectal cancer patients.

Diagnostic accuracy of portal-phase CT and MRI with mangafodipir trisodium in detecting liver metastases from colorectal carcinoma

AIM

To compare the diagnostic accuracy of single section spiral computed tomography (CT) and magnetic resonance imaging (MRI) with tissue-specific contrast agent mangafodipir trisodium (MnDPDP) in the detection of colorectal liver metastases.

MATERIAL AND METHODS

One hundred and twenty-five consecutive patients undergoing surgery for primary and/or metastatic disease were evaluated using CT (5 mm collimation and reconstruction interval, pitch 2), two-dimensional fast spoiled gradient echo (2D FSPGR) T1 and single shot fast-spin echo (SSFSE) T2 weighted breath-hold MRI sequences, performed before and after intravenous administration of MnDPDP. The reference standards were intraoperative ultrasound and histology.

RESULTS

The per-patient accuracy of CT was 72.8 versus 78.4% for unenhanced MRI (p = 0.071) and 82.4% for MnDPDP-enhanced MRI (p = 0.005). MnDPDP-enhanced MRI appeared to be more accurate than unenhanced MRI but this was not significant (p = 0.059). The sensitivity of CT was 48.4% versus 58.1% for unenhanced MRI (p = 0.083) and 66.1% for MnDPDP-enhanced MRI (p = 0.004). The difference in specificity between procedures was not significant. The per-lesion sensitivity was 71.7, 74.9 and 82.7% for CT, unenhanced MRI, and MnDPDP-enhanced MRI, respectively; the positive predictive value of the procedures was respectively 84.0, 96.0 and 95.8%. MnDPDP-enhanced MRI provided a high level diagnostic confidence in 92.5% of the cases versus 82.5% for both unenhanced MRI and CT. The kappa value for inter-observer variability was >0.75 for all procedures.

CONCLUSIONS

The diagnostic accuracy and sensitivity of MnDPDP-enhanced MRI is significantly higher than single section spiral CT in the detection of colorectal cancer liver metastases; no significant difference in diagnostic accuracy was observed between unenhanced MRI and MnDPDP-enhanced MRI.

Comparison of contrast-enhanced ultrasonography versus baseline ultrasound and contrast-enhanced computed tomography in metastatic disease of the liver: diagnostic performance and confidence

AIM

The aim of this study was to compare contrast-enhanced ultrasonography (CEUS) to baseline US and contrast-enhanced computed tomography (CT) in metastatic disease of the liver diagnosed or suspected by US during presurgical staging or postsurgical follow-up for primary malignancies.

MATERIALS AND METHODS

Two hundred-fifty-three patients considered suitable for US due to the complete explorability of the liver and with one to five proven or suspected liver metastases at baseline US were included. All patients underwent US before and after microbubble injection, and multiphase contrast-enhanced CT. Independent panels of readers reviewed US and CT scans and recorded liver metastases according to a 5-grade scale of diagnostic confidence. Sensitivity, specificity (diagnostic performance) and area under the receiver operating characteristics (ROC) curve (diagnostic confidence) were calculated.

RESULTS

Reference standards revealed no metastases in 57/253, more than five in 59/253, and one to five in 137/253 patients. In patients with one to five metastases, CEUS versus baseline US revealed more metastases in 64/137 and the same number in 73/137 patients while CEUS versus CT revealed more metastases in 10/137, the same number in 99/137, and lower number in 28/137. Sensitivity, specificity, and area under ROC curve of CEUS (83%, 84%, 0.929, respectively) differed from baseline US (40%, 63%, 0.579, respectively; P<0.01) while did not differ from CT (89%, 89%, 0.945, respectively; P>0.05).

CONCLUSION

CEUS improved liver metastases diagnosis in comparison with baseline US while it revealed similar diagnostic performance and confidence to contrast-enhanced CT in patients considered suitable for US and with proven or suspected liver metastases at baseline US.

Detection and characterization of liver metastases: 16-slice multidetector computed tomography versus superparamagnetic iron oxide-enhanced magnetic resonance imaging

The aim of our study was to compare the diagnostic performance of 16--slice multidetector computed tomography with that of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging in the detection of small hepatic metastases and in the differentiation of hepatic metastases from cysts. Twenty-three patients with 55 liver metastases and 14 liver cysts underwent SPIO-enhanced MR imaging and multiphasic CT using 16-MDCT. Two observers independently analyzed each image, in random order. Sensitivity and diagnostic accuracy for lesion detection and differentiation as metastases or cysts for MDCT and SPIO-enhanced MR imaging were calculated using receiver operating characteristic analysis. For all observers, the Az values of SPIO-enhanced MR imaging for lesion detection and differentiation of liver metastases from cysts (mean 0.955, 0.999) were higher than those of MDCT (mean 0.925, 0.982), but not statistically significantly so (P > 0.05). Sensitivity of SPIO-enhanced MR imaging with regard to the detection of liver metastases (mean 94.5%) was significantly higher than that of MDCT (mean 80.0%) (P < 0.05). SPIO-enhanced MR imaging and 16-MDCT showed similar diagnostic accuracies for detection and differentiation of liver metastases from cysts, but sensitivity of SPIO-enhanced imaging in the detection of liver metastases was superior to that of 16-MDCT.

Preoperative hepatic 3D models: virtual liver resection using three-dimensional imaging technique

Emerging new techniques for liver resections set new requirements for the preoperative imaging and planning. Open surgery is a three-dimensional procedure and planning of the resection line may be difficult when basing on conventional two-dimensional CTs or MRIs, although all the information is there. With multidetector-row CT (MDCT), thin slices can be obtained with excellent temporal resolution, and precise three-dimensional (3D) models can be created. We regard 3D imaging technique useful in most liver resections. It improves the surgeon's knowledge of liver anatomy and makes even more complicated liver resections safe. Better knowledge of three-dimensional appearances of liver structures may further improve the results of curative liver surgery. However, before becoming a routine clinical procedure, research and development are still needed. Also, careful testing and evaluation of the methods have to be performed. In the future, 3D models will probably play an important role in the preoperative planning of liver resections.

Hepatic lesions deemed too small to characterize at CT: prevalence and importance in women with breast cancer

PURPOSE

To retrospectively evaluate the prevalence and clinical importance of hepatic lesions considered too small to characterize (TSTC) at initial computed tomography (CT) in women with breast cancer.

MATERIALS AND METHODS

Approval for this retrospective study was obtained from the institutional review board, which waived the requirement for informed consent. For each woman who received a diagnosis of breast cancer between 1998 and 2002, the authors reviewed the report of the first contrast material-enhanced CT examination that included assessment of the liver. For women with no definite liver metastasis and at least one hepatic lesion considered TSTC, reports of follow-up imaging examinations were reviewed for a change in lesion size; medical records and images were reviewed if there was a change in lesion size. The 95% confidence intervals (CIs) were calculated for best- and worst-case analyses of cases in which different assumptions were used to classify a lesion as benign.

RESULTS

Of 7692 women, 1012 (13.2%) underwent contrast-enhanced CT including liver assessment. The mean age of the 1012 women was 54.6 years (range, 20.7-89.1 years). The median time from diagnosis of breast cancer to initial CT examination was 14.1 weeks (range, -3.7 to 296 weeks). The presence of at least one hepatic lesion deemed TSTC was reported in 277 of 941 women (29.4%) in whom no definite hepatic metastasis was reported. Subsequent imaging examinations were performed in 191 of the 277 women (69.0%) (median time from initial CT to last follow-up imaging examination, 54 weeks; range, 0.3-302 weeks). Those examinations revealed the lesions were unchanged in 175 (91.6%) women, no longer visible in eight (4.2%), and larger in six (3.1%). In two women (1.0%), change could not be determined. The enlarging hepatic lesions deemed TSTC represented metastatic breast cancer (three patients), metastatic pancreatic cancer (one patient), or cysts (one patient); in one patient, the etiology was not known. Results of best- and worst-case analyses showed that the lesions were benign in 96.9% (95% CI: 93%, 99%) and 92.7% (95% CI: 88%, 96%) of women, respectively.

CONCLUSION

In 92.7%-96.9% of women with breast cancer and hepatic lesions deemed TSTC but no definite liver metastases at initial CT, the lesions represented a benign finding.