To assess the feasibility of postprocessing dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging timing bolus data by using a three-dimensional radial gradient-echo technique with k-space-weighted image contrast (KWIC) for the characterization of solid pancreatic diseases.
Materials and methods:
This retrospective study was approved by the institutional review board, and informed consent was waived. A total of 45 patients suspected of having biliary or pancreatic disease underwent pancreatic MR examination with a 3.0-T imager with a low-dose (2 mL gadopentetate dimeglumine) timing bolus by using the radial KWIC technique. There were 24 patients with pancreatic cancers, eight with pancreatic neuroendocrine tumors (PNETs), three with chronic pancreatitis, and 10 with a normal pancreas. By using a dedicated postprocessing software program for DCE MR imaging, the following perfusion parameters were measured for tumor and nontumorous parenchyma: volume transfer coefficient (K(trans)) and extracellular extravascular volume fraction; the rate constant (k(ep)) and initial area under the concentration curve in 60 seconds (iAUC) were then generated. The perfusion parameters acquired on DCE MR images were compared among the groups by using the analysis of variance test.
K(trans), k(ep), and iAUC values in patients with pancreatic cancer (0.042 min(-1) ± 0.023 [standard deviation], 0.761 min(-1) ± 0.529, and 2.841 mmol/sec ± 1.811, respectively) were significantly lower than in patients with a normal pancreas (0.387 min(-1) ± 0.176, 6.376 min(-1) ± 2.529, and 7.156 mmol/sec ± 3.414, respectively) (P < .05 for all). In addition, k(ep) values of PNETs and normal pancreas also differed (P < .0001), and K(trans), k(ep), and iAUC values of pancreatic cancers and PNETs differed significantly (P < .0001, P = .038, and P < .0001, respectively).
Results of timing bolus DCE MR imaging with the radial KWIC sequence from routine examinations can be postprocessed to yield potentially useful perfusion parameters for the characterization of pancreatic diseases.
[Show abstract][Hide abstract] ABSTRACT: To confirm the feasibility of breath-hold DCE-MRI and DWI at 3T to obtain the intra-abdominal quantitative physiologic parameters, K (trans), k ep, and ADC, in patients with untreated pancreatic ductal adenocarcinomas.
Diffusion-weighted single-shot echo-planar imaging (DW-SS-EPI) and dynamic contrast-enhanced (DCE) MRI were used for 16 patients with newly diagnosed biopsy-proven pancreatic ductal adenocarcinomas. K (trans), k ep, and apparent diffusion coefficient (ADC) values of pancreatic tumors, non-tumor adjacent pancreatic parenchyma (NAP), liver metastases, and normal liver tissues were quantitated and statistically compared.
Fourteen patients were able to adequately hold their breath for DCE-MRI, and 15 patients for DW-SS-EPI. Four patients had liver metastases within the 6 cm of Z axis coverage centered on the pancreatic primary tumors. K (trans) values (10(-3) min(-1)) of primary pancreatic tumors, NAP, liver metastases, and normal liver tissues were 7.3 ± 4.2 (mean ± SD), 25.8 ± 14.9, 8.1 ± 5.9, and 45.1 ± 15.6, respectively, k ep values (10(-2) min(-1)) were 3.0 ± 0.9, 7.4 ± 3.1, 5.2 ± 2.0, and 12.1 ± 2.8, respectively, and ADC values (10(-3) mm(2)/s) were 1.3 ± 0.2, 1.6 ± 0.3, 1.1 ± 0.1, and 1.3 ± 0.1, respectively. K (trans), k ep, and ADC values of primary pancreatic tumors were significantly lower than those of NAP (p < 0.05), while K (trans) and k ep values of liver metastases were significantly lower than those of normal liver tissues (p < 0.05).
3T breath-hold quantitative physiologic MRI is a feasible technique that can be applied to a majority of patients with pancreatic adenocarcinomas.
[Show abstract][Hide abstract] ABSTRACT: To retrospectively compare the utility of perfusion magnetic resonance imaging (MRI) in distinguishing treatment-related changes from recurrent disease in glioma patients.
Thirty-one patients with histologically diagnosed gliomas and increased enhancement after or during concurrent (chemo-) radiation therapy were enrolled. They underwent dynamic contrast-enhanced (DCE) permeability MRI followed by dynamic susceptibility contrast (DSC) perfusion MRI. The vascular transfer constant (rK(trans)) and initial areas under the concentration curve (riAUC) were obtained from DCE MRI, and cerebral blood volume (rCBV) was obtained from DSC MRI. Patients were classified as having treatment-related changes or recurrent tumours based on clinicoradiological results or pathological results from surgery.
Nineteen patients were diagnosed as having recurrences and 12 patients as having treatment-related changes. The rK(trans), riAUC, and rCBV values in the recurrent group were significantly higher than the values in the group with treatment-related changes (p < 0.05). For all 31 patients, there was no significant difference between DSC MRI and DCE MRI for the differentiating power between recurrence and treatment-related changes (p = 0.7227). However, when including only the 24 patients with concordant values of rK(trans) and riAUC, DCE MRI showed a significant AUC value of 0.786 in the receiver operating characteristic (ROC) curve analysis (p = 0.003), whereas DSC MRI did not (AUC = 0.643, p = 0.229).
MRI perfusion images appear to show promise in distinguishing treatment-related changes from recurrent tumours. When both rK(trans) and riAUC show concordant values, DCE MRI seems to be more powerful than DSC MRI in the differentiation of recurrence from treatment-related changes.
[Show abstract][Hide abstract] ABSTRACT: To compare radial volumetric imaging breath-hold examination with k-space weighted image contrast reconstruction (r-VIBE-KWIC) to Cartesian VIBE (c-VIBE) in arterial phase dynamic gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (DCE-MRI) of the liver.
We reviewed 53 consecutive DCE-MRI studies performed on a 3-T unit using c-VIBE and 53 consecutive cases performed using r-VIBE-KWIC with full-frame image subset (r-VIBEfull) and sub-frame image subsets (r-VIBEsub; temporal resolution, 2.5-3 s). All arterial phase images were scored by two readers on: (1) contrast-enhancement ratio (CER) in the abdominal aorta; (2) scan timing; (3) artefacts; (4) visualisation of the common, right, and left hepatic arteries.
Mean abdominal aortic CERs for c-VIBE, r-VIBEfull, and r-VIBEsub were 3.2, 4.3 and 6.5, respectively. There were significant differences between each group (P < 0.0001). The mean score for c-VIBE was significantly lower than that for r-VIBEfull and r-VIBEsub in all factors except for visualisation of the common hepatic artery (P < 0.05). The mean score of all factors except for scan timing for r-VIBEsub was not significantly different from that for r-VIBEfull.
Radial VIBE-KWIC provides higher image quality than c-VIBE, and r-VIBEsub features high temporal resolution without image degradation in arterial phase DCE-MRI.
• Radial VIBE-KWIC minimised artefact and produced high-quality and high-temporal-resolution images. • Maximum abdominal aortic enhancement was observed on sub-frame images of r-VIBE-KWIC. • Using r-VIBE-KWIC, optimal arterial phase images were obtained in over 90 %. • Using r-VIBE-KWIC, visualisation of the hepatic arteries was improved. • A two-reader study revealed r-VIBE-KWIC's advantages over Cartesian VIBE.
European Radiology 03/2014; 24(6). DOI:10.1007/s00330-014-3122-0 · 4.01 Impact Factor
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