Stephan Venz

The Value of Magnetic Resonance Imaging in the Diagnosis of Suspected Penile Fracture with Atypical Clinical Findings

PURPOSE We studied the use of magnetic resonance imaging (MRI) in the diagnosis of suspected penile fracture. MATERIALS AND METHODS Penile fracture diagnosis was based on classic history and typical physical signs in 8 patients who were treated surgically without any further diagnostic procedure. Sonography, cavernosography and MRI were performed in 4 patients with equivocal findings. RESULTS Only MRI identified rupture of the corpus cavernosum in all 4 cases. CONCLUSIONS MRI is the most accurate imaging procedure when penile fracture is suspected but clinical findings are unusual.

D-GALACTOSE-BASED SIGNAL-ENHANCED COLOR DOPPLER SONOGRAPHY OF BREAST TUMORS AND TUMORLIKE LESIONS

RATIONALE AND OBJECTIVES This study sought to evaluate prospectively the diagnostic potential of unenhanced and enhanced color Doppler and power Doppler for the differentiation of tumors and tumorlike lesions of the breast. METHODS Ninety-two patients with 110 tumors or tumorlike lesions of the breast were investigated by unenhanced and enhanced color and power Doppler ultrasound. The sonomorphologic aspects of vascularization were analyzed. In addition, maximal systolic frequency shift, resistance, and pulsatility indices were determined. RESULTS In 15 (24%) of 63 primary carcinomas, 15 (68%) of 22 fibroadenomas, and all (100%) of 14 postoperative lesions, the sonomorphologic analysis for the differential diagnosis of breast tumors was improved after contrast enhancement in color Doppler mode. In comparing unenhanced color Doppler to power Doppler, the latter was found to be slightly superior (sensitivity, 60% vs. 67%; specificity, 39% vs. 45%, respectively); after enhancement, both modes were equivalent (sensitivity, 100% vs. 100%; specificity, 95% vs. 95%, respectively). Signal enhancement resulted in a significant improvement in sensitivity and specificity (P < 0.01). Typical signs of malignancy were irregular vessel calibers, serpiginous courses, penetration of the tumors margin, and irregular reticular vascularization. The quantitative parameters proved not to be helpful for the differential diagnosis of breast tumors. CONCLUSIONS By improved analysis of the vascularization pattern, d-galactose-enhanced color Doppler sonography was found to provide more reliable differential diagnostic information than unenhanced Doppler ultrasound in tumors and tumorlike lesions of the breast.

Do ultrasonic contrast agents artificially increase maximum Doppler shift? In vivo study of human common carotid arteries.

The aim of this study was to establish whether an increase of maximum Doppler shift occurs in the human common carotid artery after the administration of Levovist, an ultrasonographic echo enhancer. Twenty common carotid arteries of 10 patients were examined. Spectral Doppler waveform examinations were performed before and after administration of Levovist using an Acuson 128 XP 10 and a 7.0 MHz transducer probe. Time averaged mean velocity, peak velocity, maximum Doppler shift, and spectral Doppler indices (pulsatility index, resistive index, systolic‐diastolic ratio) were assessed. No significant changes in any of the measured parameters, including maximum Doppler shifts, peak velocity (P = 0.35, Wilcoxon rank sum test), pulsatility indices (P = 0.70), resistive indices (P = 0.98), or other spectral indices, were found. We conclude that an increase in Doppler shift does not inevitably occur after the administration of a signal enhancer when examining the human common carotid artery.

Contribution of color and power Doppler sonography to the differential diagnosis of acute and chronic rejection, and tacrolimus nephrotoxicity in renal allografts

The aim of the present study was to differentiate acute rejection, chronic rejection, and tacrolimus nephrotoxicity with color and power Doppler imaging of renal transplants. One hundred examinations were obtained from 45 patients. Pulsatility and resistive indices were calculated from color Doppler images. The grade of renal vascularization was quantified using computer‐assisted pixel analysis in a rectangular region‐of‐interest. The percentage of vessel‐covered renal parenchyma (POV) was calculated using a histogram that discriminated renal vessels from renal parenchyma via power Doppler images. Furthermore, the distance from the most peripherally located vessels to the renal capsule (PVD) was measured. A reduced POV ± 55 % proved to be the best discriminator when chronic rejection was suspected (sensitivity 79 %, specificity 87 %). Tacrolimus nephrotoxicity showed not only a moderate elevation of the Doppler signal but also an increased PVD±3.9 mm and a normal POV. We conclude that the evaluation of renal vessels by power Doppler images improves diagnostic accuracy for patients with renal allografts.