Double-contrast Magnetic Resonance Imaging Research Articles

Detection of Small Hepatocellular Carcinoma

To investigate whether gadoxetic acid-enhanced magnetic resonance imaging (MRI) has the diagnostic capability and sensitivity comparable to the combination of gadopentetate dimeglumine-enhanced MRI and superparamagnetic iron oxide-enhanced MRI (double-contrast MRI) in the detection of small hepatocellular carcinomas (HCCs). Forty-one patients with 56 HCCs (size range, 0.5-2.0 cm) who underwent gadoxetic acid-enhanced MRI and double-contrast MRI with a mean interval of 4 days (range, 3-9 days) were included in this study. HCCs were diagnosed by histology (n = 25) and imaging findings (n = 31). Two observers independently reviewed the gadoxetic acid set (unenhanced, early dynamic, and hepatocyte phase images) and the double-contrast MRI set, at an initial reading session, and then reached consensus. Diagnostic accuracy and sensitivity were evaluated using the alternative-free response receiver operator characteristic method. Diagnostic accuracy (AZ) and sensitivity were similar for both image sets (0.955, 83.9% for gadoxetic acid set; 0.952, 80.4% for double-contrast MRI set) (P > 0.05). There were 5 and 3 HCCs that were verified only on the gadoxetic acid set and double-contrast MRI set, respectively. All 9 HCCs that were not verified on the gadoxetic acid set were assigned a low confidence rating of 1 or 2. However, 3 of the 11 HCCs, which were not verified on double-contrast MRI, were not seen even upon retrospective review. Gadoxetic acid-enhanced MRI can replace double-contrast MRI for the detection of HCCs. Because all HCCs were delineated on gadoxetic acid-enhanced MRI, even with a low confidence rating, and 3 HCCs were not seen on double-contrast MRI, gadoxetic acid-enhanced MRI could be more advantageous than double-contrast MRI for HCC work-up.

Characterization of liver metastases: the efficacy of biphasic magnetic resonance imaging with ferucarbotran-enhancement

To retrospectively evaluate the efficacy of biphasic magnetic resonance imaging (MRI) of the liver with ferucarbotran-enhancement for the characterization of hepatic metastases. Thirty-six patients underwent MRI of the liver with separate acquisition of double-contrast enhancement consisting of gadolinium and ferucarbotran. A total of 106 focal hepatic lesions (51 metastases, 31 cysts, 23 haemangiomas, and one eosinophilic abscess) were included. Two sets of MRI were analysed: (1) ferucarbotran set: ferucarbotran-enhanced T1-weighted (T1W) dynamic imaging combined with ferucarbotran-enhanced T2*-weighted (T2*W) delayed imaging and (2) double set: gadolinium-enhanced T1W dynamic imaging combined with ferucarbotran-enhanced T2*W delayed imaging. The diagnostic accuracy of the two sets was evaluated using alternative free-response receiver operating characteristic curve analysis. Sensitivity and specificity were compared using the McNemar test. The enhancement pattern of focal hepatic lesions was analysed on gadolinium and ferucarbotran-enhanced T1W dynamic imaging. There was no significant difference in the accuracy of characterizing hepatic metastases between the two sets. Sensitivity and specificity were not significantly different between the sets (p>0.05). Peripheral rim enhancement was exhibited in 57% of metastatic lesions on ferucarbotran-enhanced T1W dynamic imaging. The majority (96%) of hepatic haemangiomas demonstrated typical peripheral nodular enhancement with progression on ferucarbotran-enhanced T1W dynamic imaging and were easily differentiated from metastases. Biphasic MRI of the liver with ferucarbotran-enhancement alone provided comparable diagnostic efficacy to double-contrast MRI for the characterization of hepatic metastases.

Double-contrast Magnetic Resonance Imaging in Preoperative Evaluation of Rectal Cancer: Use of Aqueous Jelly as Luminal Contrast

Carcinoma of the rectum is one of the most common malignant tumours in the Western world. Preoperative knowledge of the local spread of rectal cancer is essential in the determination of the therapeutic strategy for this disease. Magnetic resonance imaging (MRI) has been described as being accurate in the detection of the extent of rectal cancer for staging. In particular, double-contrast material enhanced MRI of the rectum has been reported to better delineate tumours against the lumen and the normal mucosa [1]. Tissue characterization is excellent with MRI and can be improved further for staging of rectal cancer by enhancement of the mucosa with intravenously administered gadoliniumbased contrast combined with intraluminal contrast material to distend the bowel. Tumour detection and assessment of penetration through the rectal wall is important information for the surgeon [2]. Piippo et al [3] concluded that tumour detection may be problematic in an undistended bowel and may result in extended examination time and inadequate imaging planes that are not perpendicular to the tumour to allow accurate analysis. Several investigators have advocated the use of rectal contrast medium for improving the delineation of tumour and to estimate its extent within the rectum [3e7]. Contrast agents that have been used are superparamagnetic iron oxide solutions, methylcellulose, and barium suspensions [5]. Herein, we describe our experience with aqueous gel as intraluminal contrast material for preoperative staging of rectal cancer.

Focal Liver Lesions: Detection and Characterization at Double-Contrast Liver MR Imaging with Ferucarbotran and Gadobutrol versus Single-Contrast Liver MR Imaging

To retrospectively compare, in a multiobserver study, double-contrast-material (sequential administration of ferucarbotran and gadobutrol) magnetic resonance (MR) imaging with single-contrast-material ferucarbotran-enhanced and dynamic postferucarbotran gadobutrol-enhanced MR imaging for the detection and characterization of benign and malignant focal liver lesions. This study was institutional review board approved, and the requirement for informed patient consent was waived. Eighty-nine patients with a total of 128 focal liver lesions underwent double-contrast liver MR imaging (nonenhanced, ferucarbotran-enhanced, and dynamic postferucarbotran gadobutrol-enhanced MR imaging performed during one session). Four readers independently reviewed the data sets during three reading sessions focused on focal liver lesion detection and characterization: In session 1, the nonenhanced and dynamic postferucarbotran gadobutrol-enhanced images obtained at double-contrast MR imaging were analyzed. In session 2, the nonenhanced and ferucarbotran-enhanced images were analyzed. In session 3, all MR images were analyzed together. The diagnostic performance of each MR technique and each reader was evaluated by using receiver operating characteristic (ROC) analysis; differences between postferucarbotran gadobutrol-enhanced, ferucarbotran-enhanced, and double-contrast MR imaging were assessed at Wilcoxon signed rank testing; and interreader agreement was assessed at Cohen kappa analysis. Histopathologic confirmation or an unchanged clinical course or MR finding was the reference standard. The four readers' detection of the benign and malignant lesions was not significantly different (P > or = .11) between the three MR techniques. The benign and malignant focal liver lesions were differentiated with significantly higher confidence (P < or = .01) on the double-contrast (area under ROC curve [A(z)] = 0.988) and ferucarbotran-enhanced (A(z) = 0.985) MR images than on the dynamic gadobutrol-enhanced images (A(z) = 0.963). Accuracy in the diagnosis of hepatocellular carcinoma (HCC) was highest (P = .02) and confidence in the final diagnosis of HCC (P = .001) or metastasis (P = .049) was significantly higher with double-contrast imaging. In select cases, double-contrast MR imaging can improve diagnostic accuracy and increase confidence in characterizing focal liver lesions as HCC or metastasis.

Double-contrast magnetic resonance imaging of the small and large bowel: effectiveness in the evaluation of inflammatory bowel disease

Double-contrast magnetic resonance imaging (DC-MRI) is a technique for imaging the intestine, which has shown to be very effective in assessing inflammatory bowel disease (IBD), and particularly Crohn's disease (CD). The expression derives from the association of two different contrast agents, a superparmagnetic intestinal and a paramagnetic intravenous contrast agent. This specific contrast media combination provides optimization of the tissue contrast, both on T1- and T2-weighted images, thus allowing an effective display of small and large bowel loops in normal and pathologic conditions. Therefore, main CD complications (strictures, fistulas, and abscesses), as well as disease activity, may be valuably assessed. The term DC-MRI may also be referred to the typical "double contrast" effect that is produced by this technique at the level of the inflamed bowel wall, both on T1- and T2-weighted images, directly related to the degree of wall inflammation (disease activity).

Usefulness of Combining Sequentially Acquired Gadobenate Dimeglumine-Enhanced Magnetic Resonance Imaging and Resovist-Enhanced Magnetic Resonance Imaging for the Detection of Hepatocellular Carcinoma

To investigate the diagnostic efficacy of sequentially acquired gadobenete dimeglumine-enhanced 3-dimensional dynamic magnetic resonance imaging (MRI) and Resovist-enhanced MRI for detecting hepatocellular carcinoma (HCC) by comparing with combined computed tomography (CT) hepatic arteriography (CTHA) and CT arterioportography (CTAP) using 16-slice multidetector CT. Twenty-nine patients with 50 HCCs underwent sequentially acquired double-contrast MRI--gadobenate dimeglumine-enhanced dynamic MRI and Resovist-enhanced MRI--and combined CTHA and CTAP using 16-slice multidetector CT. Dynamic MRI was obtained using volumetric interpolated technique and sensitivity encoding on a 1.5-T unit. Resovist-enhanced MRI was composed of T2-weighted turbo spin-echo and T2*-weighted gradient echo sequences. Sensitivity, positive predictive value, and diagnostic accuracy for double-contrast MRI, gadolinium-enhanced MRI, and combined CTHA and CTAP were calculated by 2 observers using an alternative-free response receiver operating characteristic analysis. For all observers, the Az values of double-contrast MRI (mean, 0.96) and combined CTHA and CTAP (mean, 0.93) were similar, which tended to be better than that of gadolinium-enhanced MRI (mean, 0.91). The sensitivity of double-contrast MRI (mean, 93%) and combined CTHA and CTAP (mean, 92%) was equivalent for all observers, which was better than that of gadolinium-enhanced MRI (mean, 85%; P < 0.05). The positive predictive value of double-contrast MRI was better than that of combined CTHA and CTAP (P < 0.05). The sequentially acquired double-contrast MRI and combined CTHA and CTAP showed a similar diagnostic accuracy and sensitivity for detecting HCC.

Double-contrast magnetic resonance imaging of hepatocellular carcinoma after transarterial chemoembolization

The purpose of this study was to assess the accuracy of double-contrast magnetic resonance (MR) imaging for the treatment response evaluation of hepatocellular carcinoma (HCC) in cirrhotic liver after transarterial chemoembolization (TACE). Twenty-two patients with 30 HCC nodules treated by TACE underwent double-contrast MR imaging 1 month after treatment. MR images were obtained before and after the sequential administration of superparamagnetic iron oxide (SPIO) and gadopentetate dimeglumine contrast agent within the same imaging session. Two observers retrospectively assessed all treated nodules for evidence of residual viable tumor after TACE. The diagnostic performance of gadolinium-enhanced, SPIO-enhanced, and double-contrast enhanced images was calculated. Histopathological and angiographical findings served as standard of reference. Receiver operating characteristic curves and areas under the curves (A (z)) were calculated. Double-contrast technique (A (z) = 0.95) was significantly (p = 0.036) more accurate than SPIO-enhanced technique (A (z) = 0.92) and gadolinium-enhanced technique (p = 0.005) (A (z) = 0.81) in viable tumor detection after TACE. Double-contrast technique was significantly more sensitive (92%) than SPIO-enhanced technique (80%) and gadolinium-enhanced technique (68%). Kappa values for interobserver agreement ranged from 0.67 to 0.87 and were significantly different from zero (all p < 0.001). Compared to gadolinium-enhanced and SPIO-enhanced techniques, double-contrast technique significantly improves the detection of viable tumor in HCC after TACE.

Clinical impact of magnetic resonance imaging on Gamma Knife surgery for brain metastases

Stereotactic radiosurgery is beneficial for patients with a limited number of small brain metastases. Increased numbers of brain metastases, not infrequently at unreachable locations, are identified using thin-section magnetic resonance (MR) imaging on the day of Gamma Knife surgery (GKS). To improve patient selection and design better treatment strategies, a retrospective study was conducted to determine factors that may contribute to detecting additional brain metastases on the day of GKS. A total of 100 patients with brain metastases who underwent GKS between October 2003 and May 2006 at the University of California Davis Medical Center were included in the present study. Patients were categorized by age, sex, Karnofsky Performance Scale score, status of systemic disease, histological characteristics of the primary tumor, and whether they received previous whole-brain radiotherapy (WBRT). The number of lesions identified by diagnostic MR imaging at referral, by thin-section double-contrast MR imaging on the day of GKS, and the actual lesions treated by GKS were recorded. The diagnostic MR images were categorized in terms of section thickness and time interval before GKS. The characteristics of this patient population match well with the general GKS practice. Fifty-six had been treated with WBRT. On average, patients presented with 2.2 +/- 1.7 lesions, a number based on their original diagnostic MR imaging, had 3.6 +/- 3.4 lesions identified on the thin-section treatment MR imaging (p < 0.05), and underwent treatment of 3.1 +/- 2.6 lesions on the day of GKS. Significantly, treatment was compromised in 21 patients, in whom not all additional lesions could be treated with the initial headframe placement. Analysis shows that a significantly greater number of lesions were detected using thin-section MR imaging on the day of GKS in patients who had undergone thick-section diagnostic MR imaging, did not receive WBRT, and had progressive systemic disease. To optimize treatment planning and minimize additional treatment, the number of metastases needs to be determined accurately before frame placement, ideally by performing thin-section MR imaging, as used on the day of GKS.

Double-contrast MRI (DC-MRI) in the study of the cirrhotic liver: utility of administering Gd-DTPA as a complement to examinations in which SPIO liver uptake and distribution alterations (SPIO-LUDA) are present and in the identification and characterisation of focal lesions

The aim of this study was to compare the performance of double-contrast magnetic resonance imaging (DC-MRI) with the sequential use of superparamagnetic iron oxide (SPIO) and gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) contrast agents compared with unenhanced MRI and SPIO-enhanced MRI (SPIO-MRI) in the study of the cirrhotic liver. Special attention was paid to cases in which alterations of liver uptake and distribution of the SPIO contrast medium [SPIO-liver uptake and distribution alterations (SPIO-LUDA)] could lead to diagnostic errors at SPIO-MRI. We used DC-MRI to study 67 patients suffering from hepatic cirrhosis and on a waiting list for liver transplant. The study was performed with a 1.5-Tesla device and characterised by three phases: the first phase without contrast material (unenhanced MRI), the second after the administration of ferumoxides (SPIO-MRI), and the third, a double-contrast study following the injection of a bolus of paramagnetic contrast material (DC-MRI). The sensitivity of unenhanced MRI, SPIO-MRI and DC-MRI in identifying and characterising hepatic focal lesions was assessed, together with the diagnostic increment of one technique with respect to the others. The gold standard was histological confirmation in 38 cases and clinical-radiological follow-up in all cases. Liver function, kidney function, blood tests and urinalysis were performed in all patients 24-48 h before and after the MRI examination. In 14/67 cases (20.8%), SPIO-LUDA were present, which posed a limitation to the SPIO-MRI examination. Focal lesions were absent in 44 patients, and the action of the ferumoxides was reduced by the presence of SPIO-LUDA in nine cases. There were five cases of confluent fibrosis, two of decompensated cirrhosis, one of vascular thrombosis, and one of scarring in a patient who had undergone hepatic resection for hepatocellular carcinoma (HCC). In all these cases, completion of the MR examination with the DC technique clarified the MR picture, confirming the absence of focal lesions. Twenty-three patients had a total of 68 lesions, which consisted of 37 dysplastic nodules (DN), 19 HCC nodules, two relapses of HCC following chemoembolisation, two HCC associated with portal thrombosis, one cancer-cirrhosis, two angiomas and five small cysts. SPIO-LUDA were present in five patients, thus limiting the identification, characterisation or assessment of the real size of the lesions. SPIO-LUDA were the result of vascular thrombosis in one case and fibrosis in four cases. In all of these cases, DC-MRI proved useful for diagnosis. The sensitivity of unenhanced MRI, SPIO-MRI and DC-MRI for lesion detection was 57.3%, 67.6% and 75%, respectively. The results obtained in the characterisation of the lesions were 20.5%, 63.2% and 73.5% for unenhanced MRI, SPIO-MRI and DC-MRI, respectively. The diagnostic increment of SPIO-MRI over unenhanced MRI for lesion identification and characterisation was 9% and 42.7%, respectively, whereas the diagnostic increment of DC-MRI over SPIO-MRI was 7.4% and 10.3%, respectively. In our study, the combined use of two contrast agents, negative and positive, provided greater diagnostic confidence and caused no side effects in the patients.

Hepatocellular Carcinoma in the Cirrhotic Liver: Double-Contrast MR Imaging for Diagnosis

To measure the sensitivity and accuracy of double-contrast magnetic resonance (MR) imaging for the diagnosis of hepatocellular carcinoma (HCC) in the cirrhotic liver. Twenty-seven patients with MR features of dysplastic nodules and/or HCC were examined. T2-weighted spin-echo and T1-weighted gradient-echo imaging was performed before and after superparamagnetic iron oxide (SPIO) administration and immediately followed by T1-weighted gradient-echo imaging at 10, 40, and 120 seconds after bolus injection of a gadolinium-based contrast material. Nonenhanced, nonenhanced plus SPIO-enhanced, and nonenhanced plus SPIO-enhanced plus gadolinium-enhanced images were reviewed. Alternative-free response receiver operating characteristic (ROC) methodology was used to analyze the results, which were correlated with histopathologic findings after transplantation in 15 patients and at biopsy in 12. Lesions visualized with all three techniques were characterized as a dysplastic nodule or HCC, and ROC analysis was performed. For all observers, SPIO-enhanced MR imaging (mean accuracy, 0.76) was more accurate than nonenhanced MR imaging (mean accuracy, 0.64) (P <.04), and double-contrast MR imaging (mean accuracy, 0.86) was more accurate than SPIO-enhanced imaging (P <.05). Both types of lesions were correctly characterized with all three techniques, although observer confidence for lesion characterization was greatest with double-contrast MR imaging. Double-contrast MR imaging significantly improves the diagnosis of HCC compared with SPIO-enhanced and nonenhanced imaging (P <.01).

Rectal carcinoma: double-contrast MR imaging for preoperative staging.

To evaluate and compare the imaging findings and staging of rectal carcinoma by using conventional magnetic resonance (MR) imaging, MR imaging with an enema of superparamagnetic ferristene-based contrast material, and MR imaging with an enema of ferristene solution plus intravenous injection of gadodiamide. Twenty-nine patients (17 women, 12 men; age range, 39-91 years) referred with a diagnosis of rectal carcinoma were examined. Analysis of the rectal wall and staging of the tumor were performed. In all patients, the MR imaging findings were correlated with the histopathologic findings. The contrast material enema caused distention of the rectum and an intraluminal signal void, whereas the gadodiamide injection caused enhancement of the mucosa on T1-weighted images. This enhancement enabled evaluation of the normal rectal wall and differentiation of the mucosa, tunica muscularis, and perirectal space, which was not possible on the nonenhanced images. Double-contrast (ferristene solution plus gadodiamide) MR imaging was superior to imaging with only ferristene-based contrast material and had a sensitivity of 100%, specificity of 70%, and accuracy of 90% in distinguishing tumor stages worse than Dukes A. Double contrast material-enhanced MR imaging enables accurate rectal carcinoma staging, which is not possible at nonenhanced imaging.

Magnetic resonance imaging with ferumoxil, a negative superparamagnetic oral contrast agent, in the evaluation of ulcerative colitis

OBJECTIVE: The introduction of new oral contrast agents that enhance image quality has increased the importance of magnetic resonance imaging (MRI) in the management of ulcerative colitis. The aim of our study was to investigate the usefulness of a new negative superparamagnetic oral contrast (ferumoxil) alone or in association with gadolinium i.v. in the assessment of the disease. METHODS: Twenty-eight patients with clinically active ulcerative colitis and 10 control subjects entered the study. In each patient a clinical, endoscopic, histological, and MRI evaluation was performed. In particular, in 14 patients affected by ulcerative colitis (group A) and in five controls, magnetic resonance images were acquired 1 h after the oral administration of 900 ml of ferumoxil, while the remaining 14 patients (group B) and five controls were submitted to double-contrast MRI (ferumoxil and gadolinium). In both groups, wall thickness, length of affected bowel segments, and, in group B, also percent contrast enhancement were calculated. RESULTS: The comparison of endoscopic and MRI extent of disease was statistically significant. Wall thickness and, in group B, also percent contrast enhancement were significantly correlated with clinical and endoscopic activities. In each group wall thickness was significantly different in the activity phases of the disease. CONCLUSIONS: MRI with negative superparamagnetic oral contrast is comparable to endoscopy in the assessment of ulcerative colitis. The double-contrast imaging does not provide more information than single oral contrast, so we concluded that the latter is preferable in the follow-up of the disease and in patients unable or with a poor compliance to undergo endoscopy.

Staging of rectal cancer by double-contrast MR imaging using the rectally administered superparamagnetic iron oxide contrast agent ferristene and IV gadodiamide injection: Results of a multicenter phase II trial

The aim of this study was to assess the accuracy of double-contrast magnetic resonance imaging (MRI) with rectal application of the superparamagnetic iron oxide contrast agent (SPIO) ferristene and IV gadodiamide for preoperative staging of rectal cancer. In a randomized phase II dose-ranging trial, 113 patients were studied preoperatively with one of four different formulations of ferristene (Abdoscan) as an enema before MRI. T1-weighted spin-echo (T1w SE) and T2w turbo spin-echo (TSE) single-contrast images were obtained as well as T1w SE and gradient-echo (GRE) double-contrast images after IV gadodiamide injection (Omniscan). Images were assessed qualitatively, and TNM tumor stage was compared with histopathology. High-viscosity ferristene formulations were superior to low-viscosity formulations in tumor staging (accuracy 90% vs 74%, P < 0.01). There was no significant difference between high and low iron content ferristene. MRI had a sensitivity of 97%, specificity of 50%, and accuracy of 82% for staging of rectal carcinoma higher than T2 stage. At receiver operator characteristic (ROC) analysis, MR differentiation between T1/T2 and T3/T4 tumor stages yielded a ROC index of 0.848. Double-contrast MRI is an accurate method for preoperative staging of rectal cancer.