Accelerated dynamic MR imaging with a parallel imaging technique for hypervascular hepatocellular carcinomas: Usefulness of a test bolus in examination and subtraction imaging

Abstract

Purpose:To assess the impact of the accelerated dynamic MR imaging (ADMRI) approach using parallel imaging for detecting hypervascular hepatocellular carcinomas (HCCs) and to evaluate the usefulness of a test bolus in examination and subtraction imaging in this setting. Materials and Methods:Thirty patients with 135 HCCs underwent ADMRI using a two-dimensional gradient-recalled echo sequence with parallel imaging. Seventeen patients were evaluated without a test bolus and 13 patients with a test bolus. The detectability of HCCs was calculated between the groups with and without a test bolus. ADMRI was evaluated regarding the signal-to-noise ratio (SNR) of the lesion and the liver, the contrast-to-noise ratio (CNR) of the lesion vs. the liver, and the feasibility of subtraction images.Results: ADMRI with and without a test bolus had almost equal sensitivity (92.5% and 92.6%). No significant difference was seen in the SNR of lesions and the CNR of lesions vs. livers between both groups. With a test bolus, ADMRI could depict the peak enhancement of nodules on the 2nd or 3rd dynamic phases and optimized the timing of peak lesion enhancement. Subtraction images could be obtained regarding minimal slice misregistration. FOR ROUTINE EXAMINATIONS OF THE LIVER, precontrast and multi-phase dynamic CT and MR imaging are generally performed; scanning of the whole liver is needed, and requires about 20 -30 seconds to obtain one phase with a single breath-hold (1-7). Murakami et al (8) reported that double arterial phase CT imaging improved detection of hypervascular hepatocellular carcinomas (HCCs) and reduced false-positive lesions with multislice helical CT. However, since the radiation doses to patients are about 30%-50% greater with multislice helical CT as a result, primarily, of scan overlap, the radiation exposure from CT to patients is under discussion (9). ConclusionDynamic MR imaging with a parallel imaging technique can be performed without radiation exposure. Furthermore, the acquisition time can be about half that without parallel imaging (10,11). Using an array of multiple receivers, the parallel imaging technique allows reduction of the scan time in standard Fourier imaging by increasing the distance between sampling lines in k-space. The purpose of the present study was to assess the clinical feasibility of accelerated dynamic MRI (ADMRI) of the whole liver with parallel imaging in routine hepatic imaging, and to evaluate the usefulness of a test bolus in examination and subtraction imaging in this setting. MATERIALS AND METHODSThis study included 65 patients (48 males and 17 females; age range, 43-84 years; mean age, 66.2 years) referred to MR imaging between July, 2001 and April, 2002, with suspicion of having HCCs clinically or based on high levels of serum ␣-fetoprotein and/or proteins induced by vitamin K antagonist , or from the results of previous ultrasonography or helical CT. For 65 of these patients, 30 underwent pathologic examination or angiography after MRI examinations. Two patients underwe...

Hepatocellular Carcinoma in Liver Transplantation Candidates: Detection with Gadobenate Dimeglumine–Enhanced MRI

“…A 3D gradient-echo sequence and parallel acquisition techniques facilitate dynamic contrast-enhanced imaging of HCC [7][8][9][10][11][12]. Gadobenate dimeglumine has been found useful for liver MRI.…”

Diagnostic Accuracy of Multi-/Single-Detector Row CT and Contrast-Enhanced MRI in the Detection of Hepatocellular Carcinomas Meeting the Milan Criteria before Liver Transplantation

“…With the recent introduction of 3D T 1 -weighted imaging and parallel acquisition techniques for MRI, imaging acquisition time has been remarkably shortened and the z-axis spatial resolution has been improved [31][32][33] . The combined use of both techniques allows acquisition of dynamic liver MR images with double arterial phases and thinner sections, thereby improving the detection of hypervascular HCCs [34] . Indeed, in previous studies by Kim et al [24,25] and Bhartia et al [35] , nearly the same temporal (double arterial phases) and spatial (slice thickness: 2.5-4 mm) resolution could be used in both MDCT (slice thickness: 3 mm) and MRI (slice thickness: 2.5-4 mm), explaining the superiority of MDCT and Gd-enhanced 3D T 1 -weighted MRI in detecting HCC compared to SDCT.…”

Prospective comparison of high- and low-spatial-resolution dynamic MR imaging with sensitivity encoding (SENSE) for hypervascular hepatocellular carcinoma

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