High‐field MRSI of the prostate using a transmit/receive endorectal coil and gradient modulated adiabatic localization

Purpose

To demonstrate in vivo magnetic resonance spectroscopic imaging (MRSI) of the human prostate at 4.0T using a transmit/receive endorectal coil and a pulse sequence designed specifically for this application.

Materials and Methods

A solid, reusable endorectal probe was designed for both radiofrequency transmission and reception. Finite difference time domain (FDTD) simulations were performed to characterize the coil's electric field distribution, and temperature measurements were performed in a beef tissue phantom to determine the coil's safe operating limit. The localization by selective adiabatic refocusing (LASER) pulse sequence was implemented using six gradient modulated offset independent adiabatic (GOIA) pulses for very sharp, B₁‐insensitive voxel localization.

Results

Based on the simulations and temperature measurements, the coil's safe operating limit was conservatively estimated to be 1.0W for 15 minutes. The transition width of the GOIA pulse selection profiles was only 6% of the bandwidth, compared with 22% for a specific absorption rate (SAR)‐matched conventional adiabatic pulse. Using the coil and pulse sequence described here, MRSI data were successfully acquired from a patient with biopsy‐proven prostate cancer, with a nominal voxel size of 0.34 cc in a scan time of 15 minutes.

Conclusion

This work demonstrates the safe and effective use of a transmit/receive endorectal coil for in vivo MRSI of the prostate. J. Magn. Reson. Imaging 2009;30:335–343. © 2009 Wiley‐Liss, Inc.     

Lichen planus and hepatitis C virus infection

BACKGROUND: The association of lichen planus (LP) with liver diseases is well established. The reported prevalence rates of hepatitis C virus (HCV) antibodies in patients with LP tend to appear quite variable. OBJECTIVE: The aim of this study was to assess the prevalence of HCV antibodies in a group of patients with LP and evaluate the clinical characteristics of the subgroup with LP associated with HCV. METHODS: We studied 101 patients, 57 (56.4%) women and 44 (43.5%) men with a mean age of 48 years, consecutively diagnosed with cutaneous and/or mucosal LP between January 1992 and December 2000. We used 99 age- and sex-matched controls. RESULTS: Anti-HCV antibodies were detected in nine cases (8.9%) of the LP group but only two (2.02%) of the controls. The odds ratio between the subjects with HCV positivity and those with negative HCV virus was 4.74, with a confidence interval at 95%, between 0.999 and 22.545. A statistically significant association was only demonstrated between erosive LP and infection by HCV. CONCLUSIONS: The possibility of liver disease caused by HCV should be ruled out in patients with LP, especially in the erosive form.     

Assessment of adenoidal obstruction in children: clinical signs versus roentgenographic findings

OBJECTIVE: As part of a comprehensive study of indications for tonsillectomy and adenoidectomy, we investigated the reliability of standardized clinical assessments and standardized roentgenographic assessments of adenoidal obstruction of the nasopharynx, and the degree of correlation between clinical assessments and roentgenographic assessments. METHODS: We rated the degree of patients' mouth breathing and patients' speech hyponasality on a 4-point scale (none = 1; mild = 2; moderate = 3; marked = 4), we averaged the ratings for each child to obtain a Nasal Obstruction Index, and we determined levels of interobserver agreement concerning the ratings. We classified lateral soft-tissue roentgenograms of the nasopharynx, based on assessments of adenoid size and of nasopharyngeal airway patency, as showing either no obstruction, borderline obstruction, or obstruction, and we determined levels of inter- and intraobserver agreement concerning the classifications. Finally, we determined correlations in individual patients between clinical ratings and roentgenographic ratings of nasal/nasopharyngeal obstruction, and calculated the predictive values of clinical ratings based on roentgenographic ratings as the gold standard. RESULTS: In sets of paired examinations, weighted kappa values for interobserver agreement concerning mouth breathing (total, 235 children) and speech hyponasality (total, 648 children) ranged from 0.84 to 0.91. The value for interobserver agreement concerning roentgenographic assessment of nasopharyngeal airway status (207 children) was 0.92, and for intraobserver agreement (191 children) 0.88. The Kendall's tau b value for concordance between Nasal Obstruction Index values and roentgenographic ratings (1033 children) was 0.51. Nasal Obstruction Index values at the lower and upper extremes--i.e., 1.0 and > or = 3.5, respectively--were highly predictive of concordant roentgenographic ratings. CONCLUSIONS: We conclude that standardized clinical ratings of the degree of children's mouth breathing and speech hyponasality provide reliable and reasonably valid assessments of the presence and degree of adenoidal obstruction of the nasopharyngeal airway. These clinical assessments are particularly valid at the extremes of either marked obstruction or no obstruction. Clinical assessment alone may be insufficient to establish the presence of adenoidal obstruction, but clinical assessment alone when findings are unequivocally negative can suffice to rule out adenoidal obstruction with a high degree of confidence.     

Spontaneously remitting dermatomyositis

Dermatomyositis (DM) is an inflammatory myopathy of skeletal muscle with characteristic cutaneous findings. It is a rare disorder with a bimodal age distribution that affects almost twice as many women as men. One category of DM, normal-enzyme DM, is characterized by cutaneous changes only at baseline, normal serum muscle enzyme levels and myositis demonstrated by electromyography (EMG) and/or muscle biopsy specimens. Typically, patients with normal-enzyme DM progress to severe muscle involvement and require systemic corticosteroid therapy. The patient we report has normal-enzyme DM confirmed by serial serum enzymes, EMG, and skin and muscle biopsies but is unique in that she never experienced progression of muscle weakness although muscle involvement was documented histologically and by EMG. Follow-up examination after 1 year revealed near-complete resolution of cutaneous involvement after topical therapy and no evidence of muscle weakness.     

A study of alpha1- and alpha2-adrenoceptor responsiveness in diabetic insipidus dogs

Summary— The present study was performed to investigate the participation of circulating vasopressin in alpha-adrenoceptor responsiveness. Thus, we compared the pressor responses induced by selective alpha1-or alpha2-adrenoceptor stimulation in two groups of conscious dogs: a) normal animals and b) animals with surgically-induced diabetes insipidus. In addition, platelet alpha2-adrenoceptors labelled with (³H)RX821002 were compared in the two groups. The pressor response to alpha1-adrenoceptor stimulation [ ie successive doses of noradrenaline (0.5, 1, 2, 4 μg/kg iv) after propranolol (1 mg/kg iv) plus yohimbine (0.5 mg/kg iv)] was significantly ( P < 0.05) less pronounced in diabetic insipidus than in normal dogs. In contrast, the magnitude of the pressor effects of alpha2-adrenoceptor stimulation [ ie noradrenaline after propranolol plus prazosin (1 mg/kg iv)] was the same in the two groups of animals. B_max and Kd values for (³H)RX821002 binding on platelets were similar in diabetic insipidus and normal dogs. This study shows that alpha1- (but not alpha2-) adrenoceptor responsiveness is decreased in diabetic insipidus suggesting the involvement of vasopressin in the mechanisms of the vascular alpha1 -adrenoceptor pressor response.