Application of a Dedicated Surface Coil in Dental MRI Provides Superior Image Quality in Comparison with a Standard Coil.

PURPOSE: Purpose of our research was the evaluation of a dedicated dental surface coil in comparison with a standard head and neck coil for the improvement of dental magnetic resonance imaging (MRI). MATERIALS AND METHODS: Axial T1-weighted spin echo MRI was performed by using a newly developed dental coil for MRI and a standard head and neck coil on five volunteers. In addition, MRI was implemented with dental coil on five patients. Using the Wilcoxon test, we compared the volunteers' signal-to-noise ratio (SNR) of a variety of anatomical structures (e.g., hard tooth tissue, pulp tissue, bone, muscle tissue). Also subjective evaluation of image quality was performed on both volunteers and patients. RESULTS: Compared with the head and neck coil, the mean SNR was 3.5-fold higher on an average with the dental coil (range: from 2.7 [masseter muscle] to 4.6 [pulp tissue]). That difference was statistically significant for all evaluated structures. The higher SNR also resulted in a superior image quality as determined by subjective evaluation. CONCLUSION: Dental MRI benefits profoundly from using a dedicated dental coil.

Sonographic measurement of renal pelvis wall thickness as diagnostic criterion for acute pyelonephritis in adults.

PURPOSE: Inflammatory processes may increase the urothelial thickness of the renal pyelon. Purpose of the study was to assess sonographic measurement of pyelon wall thickness (PWT) in adult patients with acute pyelonephritis, chronic urinary tract infection (UTI) and indwelling ureteral stents. MATERIALS AND METHODS: Four study groups (acute pyelonephritis n=50, chronic UTI n=10, indwelling ureteral stents n=10, controls n=25) underwent renal ultrasonography (Acuson Seqouia, Mountain View, CA; 6 MHz Transducer). The renal pyelon was imaged in transverse and longitudinal planes. PWT measurements of patients with acute pyelonephritis were repeated after successful antibiotic treatment. RESULTS: Mean PWT in healthy controls was 1.0 mm+/-0.19. In patients with acute pyelonephritis, PWT was significantly increased to 2.9 mm+/-0.89 (p<0.001). PWT decreased significantly after antibiotic treatment to 1.4 mm+/-0.47 (p<0.001). Kidneys with indwelling stents presented with a PWT of 2.7 mm+/-0.68, kidneys with chronic UTI demonstrated a PWT of 2.8 mm+/-0.62. PWT in these patient groups was significantly greater than PWT in healthy volunteers (p<0.001). The interobserver agreement was excellent (p<0.001). CONCLUSION: PWT is a reproducible diagnostic criterion for acute pyelonephritis. Based upon our experience, we suggest a cut-off value of 2.0 mm to distinguish healthy kidneys from those with urothelium thickened by inflammation. PWT cannot be used to distinguish acute pyelonephritis from chronic inflammation of the urothelium.

Comparison of contrast enhanced color Doppler targeted biopsy to conventional systematic biopsy: impact on Gleason score.

PURPOSE: Prostate cancer grading with Gleason score is an important prognostic factor. This prospective randomized study compares ultrasound systematic biopsy vs contrast enhanced color Doppler targeted biopsy for the impact on Gleason score findings. MATERIALS AND METHODS: We examined 690 men (mean age 56 years, range 41 to 77) with a serum total prostate specific antigen of 1.25 ng/ml or greater, a free-to-total prostate specific antigen ratio less than 18% and/or a suspicious digital rectal examination. Contrast enhanced color Doppler targeted biopsies with a limited number of cores (5 or less) were performed in hypervascular areas of the peripheral zone during administration of the ultrasound contrast agent Sonovuetrade mark (Bracco, Milano, Italy). Ten systematic biopsies were obtained in a standard spatial distribution. Cancer detection rates and Gleason score were compared. RESULTS: Prostate cancer was identified in 221 of 690 subjects (32%) with a mean prostate specific antigen of 4.6 ng/ml (range 1.4 to 35.0). Prostate cancer was detected in 180 of 690 subjects (26%) with contrast enhanced color Doppler targeted biopsy and in 166 of 690 patients (24%) with systematic ultrasound biopsy. The Gleason score of all 180 cancers detected on contrast enhanced color Doppler targeted biopsy was 6 or higher (mean 6.8). The Gleason score of all 166 cancers detected on systematic biopsy ranged from 4 to 6 and mean Gleason score was 5.4. Contrast enhanced color Doppler targeted biopsy detected significantly higher Gleason scores compared to systematic biopsy (Wilcoxon rank sum test p <0.003). CONCLUSIONS: Contrast enhanced color Doppler targeted biopsy detected cancers with higher Gleason scores and more cancer than systematic biopsy. Therefore, contrast enhanced color Doppler seems to be helpful in the grading of prostate cancer, which is important for defining prognosis and deciding treatment.

[Ultrasound contrast agents and prostate cancer]. / Ultraschallkontrastmittel und Prostatakarzinom.

Prostatic carcinoma is the most frequent malignant disease in men and associated with very high mortality. The diagnostic work-up of prostatic carcinoma is based on tests to determine the level of prostate-specific antigen (PSA), digital rectal examination, and transrectal sonography. Due to diagnostic limitations, ultrasound-guided prostate biopsy is the method of choice for diagnosis of prostatic carcinoma. New imaging technologies allow detection of prostatic carcinoma, thus facilitating removal of specific biopsy specimens from these regions. Introduction of ultrasound contrast agents ("echo signal enhancers") significantly increased the diagnostic potential of this method, making it possible to visualize tumor vascularization.

Guided tissue regeneration in intrabony defects using an experimental bioresorbable polydioxanon (PDS) membrane. A 24-month split-mouth study.

AIM: The comparison of the clinical, radiographic, and microbiological healing results in deep intrabony defects following GTR therapy with two different bioresorbable membranes in a prospective split-mouth design. MATERIAL AND METHODS: 31 pairs of contralateral intrabony defects were randomly treated with either an experimental Polydioxanon (PDS) membrane or a Polylactic acid (PLA) matrix barrier. After 6, 12 and 24 months, healing results were assessed using clinical examinations (REC, PPD, CAL, vertical relative attachment gain V-rAG), quantitative digital subtraction radiography (amount and area of bone density changes), and microbiological analysis. RESULTS: Postoperative membrane exposures occurred in 14 PDS and 2 PLA treated sites. 6, 12 and 24 months p.o., both membranes provided a significant gain in CAL [median values: 6 months (PDS vs. PLA: 3.0 vs. 3.0 mm); 12 and 24 months (PDS vs. PLA: 4.0 vs. 4.0 mm)], which corresponded to a V-rAG of 57.1% (PDS) vs. 62.5% (PLA) after 24 months. PDS and PLA treated sites revealed significant bone density gain 6, 12 and 24 months after surgery. 38.8% (PDS) vs. 41.8% (PLA) of the initial defect areas showed bone density gain. While the gain in bone density was significantly greater in PDS than in PLA sites, neither CAL gain nor the area of bone density changes revealed significant differences. Microbiological culture revealed similar bacterial loads in PDS and PLA sites during the first 12 months. CONCLUSION: This 24-month study indicates that the PDS and PLA membranes can provide similar favorable regeneration results in deep intrabony periodontal defects, although considerably more postoperative membrane exposures have to be expected in PDS treated sites.