Research articlePreoperative detection of malignant liver tumors: Comparison of 3D-T2-weighted sequences with T2-weighted turbo spin-echo and single shot T2 at 1.5 T
Introduction
Surgical resection remains the first-line treatment for patients with primary or secondary malignant liver tumors [1,2]. Recent improvements in liver surgery have made possible a wide range of resections, including segmentectomies, multi-segmentectomies, atypical resections and association with intraoperative ablation or preoperative endovascular treatments [3]. However, considering the morbidity of liver surgery and the lack of improvement in patient survival in case of incomplete treatment, selection of patients and preoperative imaging to determine an accurate mapping of the tumors is paramount [4].
Computed tomography (CT) remains the cornerstone for the non-invasive assessment of the burden and localization of the disease in surgical candidates to hepatic surgery. However, in the past decade, magnetic resonance imaging (MRI) has gained interest and has demonstrated improved sensitivity and specificity in the detection of liver tumors [4,5]. Diffusion-weighted imaging (DWI) and dynamic multiphasic contrast-enhanced T1-weighted MRI, have proven high degrees of sensitivity for liver lesion detection leading some authors to defend MRI protocols without T2-weighted sequences for the detection of liver lesions [6]. Despite technical refinements, the use of T2-weighted MRI sequences remains difficult for liver imaging. This is because acquisition of high resolution turbo spin-echo (TSE) or fast spin-echo (FSE) images requires several breath-holds or respiration triggered acquisitions that are time consuming and prone to artifacts [[7], [8], [9], [10]]. Some authors have proposed the use of T2-weighted single shot MRI sequences only rather than TSE or FSE sequences as they are less prone to motion artifacts. Indeed, they are acquired in a very short time during one breath hold, but with a significantly decreased spatial resolution compared to TSE or FSE sequences [11,12]. Another option is to use T2-weighted sequences with radial acquisition of the k-space techniques (PROPELLER® (General Electric Healthcare, Wauwatosa, WI USA.), BLADE® (Siemens Healthineers, Forcheim, Germany), or MultiVane® (Philips Healthcare, Eindhoven, The Netherland)). These sequences result in a reduction of artifacts due to the oversampling of the center of the k-space [13].
Recently, several manufacturers have proposed new fat-suppressed T2-weighted MRI sequences for liver imaging consisting in three-dimensional (3D) acquisitions using a modified TSE pulse [14]. These sequences called 3D T2-weighted sequences with sampling perfection with application-optimized contrast using different flip angle evolutions (3D-T2-SPACE®, Siemens Healthineers), Cube® (General Electric Healthcare), volume isotropic turbo spin echo acquisition, (Vista® Philips healthcare), 3D MultiVOXel (3D MVOX®, Toshiba, Tokyo, Japan) and iso fast spin echo (isoFSE®, Hitachi Medical Systems, Tokyo, Japan) have gained interest in the evaluation of the pelvis because of their high spatial resolution and high SNR allowing to perform multiplanar reconstructions [15,16]. However, acquisition of a single slab of thin slice data set is quite long and may be impaired by patients’ movements [17].
For liver imaging, the generally used sequences provide 4 mm contiguous slices without interleaving gap to maintain a substantial contrast-to-noise ratio (CNR) and SNR, but thinner slices are possible [18]. The use of 3D-T2-SPACE results in greater SNR, greater CNR, less artifacts and increased sensitivity for the detection of benign liver lesions compared to the more conventional T2-weighted TSE sequences [18]. 3D-T2-SPACE has also proven efficacy in the investigation of brain, genito-urinary, biliary and musculoskeletal system [19]. However, no study to date has evaluated the 3D-T2-SPACE sequence specifically for the detection of malignant liver tumors.
The purpose of this study was to assess the performances of 3D-T2-weighted SPACE sequence compared to the standard T2-weighted TSE and T2-weighted half-fourier acquisition single-shot turbo spin-echo (T2-HASTE) sequences in the preoperative detection of malignant liver tumors.
Section snippets
Patients selection
From February 2012 to December 2015, all consecutive patients over 18 years who underwent liver MRI for a preoperative evaluation of focal hepatic tumors were prospectively included. Patients with history of surgery or liver thermo-ablation were and patients with known liver lesions were excluded. This study was conducted after IRB approval following the recommendations of our institutional review board and informed consent was obtained from all patients. The indications for MRI examinations
Results
From February 2012 to December 2015, 33 patients were included (Table 2). There were 27 men and 6 women with a mean age of 63.4 years ± 8.9 (SD) (range: 40–85 years). All patients had 3D T2-weighted SPACE sequence, DW-MRI and dynamic 3D T1-weighted VIBE sequences. T2-TSE sequence was performed in 16 patients (13 men and 3 women) and T2-HASTE sequence in 17 patients (14 men and 3 women).
Thirteen patients had a total of 40 HCC nodules and 20 patients had a total of 54 non-HCC tumors (16 patients
Discussion
The present study demonstrates that 3D-T2- weighted SPACE sequence had a higher sensitivity for the detection of malignant liver tumors, a higher CNR and less artifacts compared to T2- weighted HASTE and T2- weighted TSE weighted sequences. These results are consistent with those of Takayama et al. who found similar results using 3D-T2-weighted VISTA sequences with less artifacts and a higher characterization rate for benign and malignant liver tumors than 2D T2 weighted sequences [14].
In the
Conflict of interest
There is no conflict of interest or commercial involvement by any of the authors.
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