Steady-state Precession Magnetic Resonance Imaging Research Articles

Contrast changes in portal vein and bile duct between centric and linear k-space ordering on three-dimensional segmented true fast imaging with steady-state precession magnetic resonance imaging

To compare the degree of visualization of the bile duct and portal vein in terms of the difference in k-space ordering on a three-dimensional (3D) segmented true fast imaging with steady-state precession (trueFISP) sequence. A breath-hold coronal 3D segmented trueFISP sequence was prospectively performed on 14 healthy volunteers. Images obtained with centric and linear k-space ordering in the k(x)-k(y) plane were compared by two independent radiologists qualitatively with depiction scores on a five-point scale (1=not seen to 5=excellent depiction) using the Wilcoxon signed-rank test. Images were also compared quantitatively using relative contrast values for the bile duct and portal vein against the hepatic parenchyma using a paired t-test. With centric ordering, both the mean depiction scores and relative contrast values for the portal vein were significantly lower than those with linear ordering (1.5 vs. 3.5, P<.01; and 0.08+/-0.19 vs. 0.51+/-0.10, P<.01, respectively). However, in the bile duct, there were no significant differences, only slight differences were found among the results obtained with centric and linear ordering (3.9 vs. 3.8, P=.72; and 0.59+/-0.06 vs. 0.68+/-0.06, P<.01, respectively). For visualizing the bile duct, centric k-space ordering on 3D segmented trueFISP sequence is recommended, while linear ordering is recommended for portal vein visualization.

Diagnosis and differential diagnosis of trigeminal neuralgia.

Trigeminal neuralgia is a chronic facial pain classified as a neuropathic pain. There is widespread agreement regarding the International Association for the Study of Pain definition of classical idiopathic trigeminal neuralgia as "a sudden, usually unilateral, severe, brief, stabbing, recurrent pain in the distribution of one or more branches of the fifth cranial nerve." However, there are variations in presentation that are less easy to diagnose and an erroneous diagnosis of trigeminal neuralgia is occasionally made. In patients with tumors or multiple sclerosis, trigeminal neuralgia is termed secondary. Currently, clinical manifestations are the mainstay for diagnosis because there are no objective tests to validate the diagnosis. The sensitivity and specificity of these clinical manifestations is reviewed. Magnetic resonance imaging (MRI) and three-dimensional fast-in-flow with steady-state precession MRI are performed to determine the presence of tumors or plaques of multiple sclerosis and to assess possible compressions and deformations of the trigeminal nerve. Their specificity and sensitivity regarding compressions found at the time of surgery is reviewed. Other differential diagnoses for chronic unilateral orofacial pain are discussed.