Intra-individual comparison of CAIPIRINHA VIBE technique with conventional VIBE sequences in contrast-enhanced MRI of focal liver lesions.

PURPOSE: To evaluate the impact of controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) volume interpolated breath-hold examination (VIBE) magnetic resonance imaging (MRI) technique on image quality, reader confidence, and inter-observer agreement for the assessment of focal liver lesions in comparison with the standard VIBE approach. MATERIAL AND METHODS: In this IRB-approved intra-individual comparison study, abdominal arterial and portal-venous contrast-enhanced MRI studies were retrospectively analyzed in 38 patients with malignant liver lesions. Each patient underwent both CAIPIRINHA and conventional VIBE 3T MRI within 3 months, showing stable disease. Images were evaluated using 5-point rating scales by two blinded radiologists with more than 20 and 5 years of experience in MRI, respectively. Readers scored dignity of liver lesions and assessed which liver segments were affected by malignancy (ranging from 1=definitely benign/not affected to 5=definitely malignant/affected by malignancy). Readers also rated overall image quality, sharpness of intrahepatic veins, and diagnostic confidence (ranging from 1=poor to 5=excellent). RESULTS: Reviewers achieved a higher inter-observer reliability using CAIPIRINHA when they reported which liver segments were affected by malignancy compared to traditional VIBE series (κ=0.62 and 0.54, respectively, p<0.05). Similarly, CAIPIRINHA showed a slightly higher inter-rater agreement for the dignity of focal liver lesions versus the standard VIBE images (κ=0.50 and 0.49, respectively, p<0.05). CAIPIRINHA series also scored higher in comparison to standard VIBE sequences (mean scores: image quality, 4.2 and 3.5; sharpness of intrahepatic vessels, 3.8 and 3.2, respectively, p<0.05) for both reviewers and allowed for higher subjective diagnostic confidence (ratings, 3.8 and 3.2, respectively, p<0.05). CONCLUSION: Compared to the standard VIBE approach, CAIPIRINHA VIBE technique provides improved image quality and sharpness of intrahepatic veins, as well as higher diagnostic confidence. Additionally, this technique allows for higher inter-observer agreement when reporting focal liver lesions for both dignity and allocation.

Monitoring glucocorticoid therapy: a pharmacokinetic approach.

Although glucocorticoid therapy is essential for the treatment of severe inflammatory disorders, there is no systematic approach to patient variables that may affect availability of a steroid dose. After the development of a data base of pharmacokinetic parameters, we examined glucocorticoid pharmacokinetics in 54 patients between 2 and 70 years of age using 70 pharmacokinetic studies after administration of intravenous methylprednisolone (n = 25), oral methylprednisolone (n = 15), intravenous prednisolone (n = 18), and oral prednisone (n = 12). Eleven patients had unusually rapid methylprednisolone elimination (clearance, 565 to 837 ml/min/1.73 m2; population mean, [+/- SD] 380 +/- 100 ml/min/1.73 m2) without an identifiable cause. Incomplete absorption of methylprednisolone and prednisone was observed in three patients and one patient, respectively. Evaluation of glucocorticoid pharmacokinetics in children aged 1 year 8 months to 18 years demonstrated a significant inverse correlation (r = 0.88; p less than 0.001) between prednisolone clearance and age. It is therefore important to consider age in the interpretation of pharmacokinetic data. To simplify measurement of prednisolone clearance, a single-dose single-point method was developed. This was based on a highly significant relationship between the 6-hour postdose prednisolone concentration and prednisolone clearance (log prednisolone clearance = 2.66 + [6-hour postdose concentration] [-0.00167]; r2 = 0.96; p less than 0.0001). Evaluation of glucocorticoid pharmacokinetics in the clinical setting can be used to identify abnormalities in absorption, elimination, and patient compliance. This technique can be used to individualize glucocorticoid dosing regimens.

Effect of low-dose troleandomycin on glucocorticoid pharmacokinetics and airway hyperresponsiveness in severely asthmatic children.

Fifteen hospitalized asthmatic children (8 to 18 years old) completed a 2-week randomized, parallel, double-blind placebo-controlled comparison of combination methylprednisolone and placebo troleandomycin, prednisone and troleandomycin (P-TAO) or methylprednisolone-TAO (MPn-TAO). Troleandomycin (250 mg once daily or every other day) and glucocorticoid doses were reduced by a standard protocol. Symptom scores, blood chemistries, pulmonary function tests, airway response to methacholine, and glucocorticoid pharmacokinetics were compared. In each group, a steroid dose reduction of 50% was achieved without a deterioration in symptom scores. Methacholine response was unchanged in all five on methylprednisolone alone, but decreased 3-fold to 30-fold in two of five on combination P-TAO, and four of five on combination MPn-TAO. Troleandomycin decreased MPn clearance by an average of 62% but did not alter prednisolone clearance. Low-dose TAO combined with MPn has a significant effect on methylprednisolone clearance in children, an effect equivalent to that reported with higher dose TAO (1000 mg/d) therapy. In addition, this preliminary study suggests that TAO may decrease bronchial hyperresponsiveness to methacholine in severely asthmatic children.