Pulse sequence optimization for MR imaging using a paramagnetic hepatobiliary contrast agent

Paramagnetic agents enhance contrast between tissues in magnetic resonance (MR) imaging by altering tissue relaxation times. The effect of these changes on MR image intensity depends in part on the choice of operator-controlled pulse sequence parameters. With the newly described paramagnetic hepatobiliary contrast agent, iron(III) ethylenebis-(2-hydroxyphenylglycine), Fe(EHPG)-, an in vivo experimental analysis of pulse sequence optimization was performed on the rat. We compared the enhancement of the liver divided by background noise, EL/N, of standard inversion-recovery (IR) and spin-echo (SE) T1-weighted pulse sequences and several pulse sequences theoretically predicted to have improved EL/N. Optimization of the echo time (TE = TEmin) gave a substantial (greater than 60%) increase in EL/N over the standard IR and SE pulse sequences. Images obtained with optimized repetition rate and inversion time gave only a slight additional improvement. Within the uncertainties of our relaxation measurements, the measured changes in EL/N with pulse sequence optimization corresponded well with theoretical predictions. With the experimental and theoretical data, the importance of using a short echo time to obtain maximal T1 contrast in contrast-enhanced MR imaging and the relative merits of optimized SE versus IR pulse sequences for contrast-enhanced MR imaging are discussed.     

Effect of electroacupuncture on bronchial asthma induced by ovalbumin in rats

INTRODUCTION: Asthma is a worldwide disabling chronic inflammatory airway disease characterized by an intense eosinophilic inflammatory infiltrate on bronchial mucous membranes. Among the complementary therapeutic approaches to asthma, acupuncture has been widely used. OBJECTIVE: Here we used a rat pulmonary hypersensitivity experimental model that mimics human asthma in order to address whether electroacupuncture (EA) treatment could reduce the inflammatory process. MATERIALS AND METHODS: Experimental animals were divided in four groups: control (C), immobilized (I), sham-acupuncture (SA), and acupuncture (A). All rats were sensitized with heat-solidified hen egg white implant. Using clinical acupuncture points, EA treatment began 2 days after antigen priming and was repeated on alternate days for 2 weeks. Subsequently, animals were challenged by inhalation with aggregated ovalbumin and sacrificed 24 hours later when blood samples, bronchoalveolar lavage (BAL), and lungs were collected. RESULTS: Histopathologic analyses showed that peribronchial and perivascular inflammatory cell infiltrates were significantly lower in group A compared to groups SA and I (shown to be similar to group C). Furthermore, BAL total cell count and percentage of polymorphonuclears (as well as the differential counts of neutrophils and eosinophils) were significantly reduced in group A compared to group I. Corsticosterone plasma levels were similar in all groups. CONCLUSIONS: Taken together these results show that EA efficiently diminishes the bronchial immune-mediated inflammation induced in rats and that this effect is dependent on the choice of specific acupoints.     

A non-linear morphometric feature selection approach for breast tumor contour from ultrasonic images

Ultrasound breast images have been used to improve diagnostics and decrease the number of unneeded biopsies. Malignant breast tumors tend to present irregular and blurred contours while benign ones are usually round, smooth and well-defined. Accordingly, investigating the tumor contour may help in establishing diagnosis. Herein, Mutual Information and Linear Discriminant Analysis were implemented to rank morphometric features in discriminating breast tumors in ultrasound images. Seven features were extracted from Convex Polygon and the Normalized Radial Length techniques. By applying a Mutual Information based approach, it was possible to identity features with possibly non-linear contributions to the outcome.     

Isolated limb perfusion with hyperthermia and chemotherapy: predictive factors for regional toxicity

OBJECTIVE:

Isolated limb perfusion combined with melphalan is an accepted treatment for obtaining locoregional control in advanced melanoma of the extremities and other malignant neoplasias restricted to the limb. This study aims to examine the factors associated with toxicity caused by the regional method. We considered the technical aspects of severe complications associated with the procedure in an attempt to diminish the patient morbidity that occurs during the learning curve.

METHODS:

We conducted a retrospective analysis of the records of patients who underwent perfusion at the AC Camargo Hospital in São Paulo, Brazil between January 2000 and January 2009. The Wieberdink scale was applied to classify local toxicity and its relation to clinical and laboratory variables.

RESULTS:

Fifty-eight perfusions were performed in 55 patients. Most patients (86.2%) presented a toxicity level between I and III. Grade V toxicity was seen in five cases (8.6%), four of which occurred in the first 2 years. Creatine phosphokinase, an important predictive factor for toxicity, had an average value of 231.8 for toxicity grades I-III and 1286.2 for toxicity grades IV-V (p = 0.001). There was a relationship between the melphalan dose and toxicity, which was 77 mg (25 to 130 mg) for toxicity grades I-II and 93.5 mg (45 to 120 mg) for toxicity grades IV-V (p = 0.0204).

CONCLUSION:

It is possible to prevent the toxicity associated with melphalan by adjusting the dose according to the patient''s body weight (especially for women and obese patients) and the creatine phosphokinase values in the postoperative period.