Antonius Schuster

Comparison Of Contrast Enhanced Color Doppler Targeted Biopsy With Conventional Systematic Biopsy: Impact On Prostate Cancer Detection

Purpose: We performed a prospective study to determine whether a limited biopsy approach with contrast enhanced color Doppler ultrasound targeted biopsy of the prostate would detect cancer as well as gray scale US guided systematic biopsy with a larger number of biopsy cores.Materials and Methods: We examined 230 male screening volunteers with a total prostate specific antigen of 1.25 ng./ml. or greater and free-to-total prostate specific antigen less than 18%. Two independent examiners evaluated each subject and a single investigator performed 5 or fewer contrast enhanced targeted biopsies into hypervascular regions in the peripheral zone during intravenous infusion of the US contrast agent Levovist (Schering, Berlin, Germany). Subsequently another examiner performed 10 systematic prostate biopsies. The cancer detection rates of the 2 techniques were compared.Results: Cancer was detected in 69 of the 230 patients (30%), including 56 (24.4%) by contrast enhanced targeted biopsy and in 52 (22.6%) by system...

Pulmonary gas exchange after cardiopulmonary resuscitation with either vasopressin or epinephrine

Objective It is well established that epinephrine administered during cardiopulmonary resuscitation results in pulmonary gas exchange disturbances. It is uncertain how vasopressin affects gas exchange after cardiopulmonary resuscitation. Design Prospective, randomized experimental study. Setting Animal research laboratory. Subjects Twenty domestic pigs. Interventions Animals were subjected to ventricular fibrillation and cardiopulmonary resuscitation by using either vasopressin or epinephrine. Hemodynamic and pulmonary gas exchange (multiple inert gas elimination technique) variables were recorded before cardiopulmonary resuscitation and 10, 30, 60, and 120 mins after return of spontaneous circulation when either epinephrine (control) or vasopressin was used. Measurements and Main Results At 10 mins after return of spontaneous circulation, blood flow to low VA/Q lung units was increased in animals treated with epinephrine (17.8 ± 6 vs. 2.6 ± 3%, mean ± sd, p < .01). Resulting carbon dioxide elimination was impaired in animals treated with epinephrine but not in animals treated with vasopressin (Paco2, 55 ± 2 vs. 46 ± 4 torr, p < .05). Thirty minutes after return of spontaneous circulation, blood flow to lung units with a normal VA/Q ratio was reduced in animals treated with epinephrine (79 ± 1 vs. 84 ± 12%, p < .05), resulting in a depressed Pao2 (147 ± 4 vs. 127 ± 10 torr, p < .05). Conclusion Vasopressin compared with epinephrine for cardiopulmonary resuscitation resulted in better gas exchange variables in the early postresuscitation phase.

Comparison of contrast-enhanced color Doppler targeted biopsy to conventional systematic biopsy: impact on prostate cancer detection

PURPOSE We performed a prospective study to determine whether a limited biopsy approach with contrast enhanced color Doppler ultrasound targeted biopsy of the prostate would detect cancer as well as gray scale US guided systematic biopsy with a larger number of biopsy cores. MATERIALS AND METHODS We examined 230 male screening volunteers with a total prostate specific antigen of 1.25 ng./ml. or greater and free-to-total prostate specific antigen less than 18%. Two independent examiners evaluated each subject and a single investigator performed 5 or fewer contrast enhanced targeted biopsies into hypervascular regions in the peripheral zone during intravenous infusion of the US contrast agent Levovist (Schering, Berlin, Germany). Subsequently another examiner performed 10 systematic prostate biopsies. The cancer detection rates of the 2 techniques were compared. RESULTS Cancer was detected in 69 of the 230 patients (30%), including 56 (24.4%) by contrast enhanced targeted biopsy and in 52 (22.6%) by systematic biopsy. Cancer was detected by targeted biopsy alone in 17 patients (7.4%) and by systematic biopsy alone in 13 (5.6%). The overall cancer detection rate by patient was not significantly different for targeted and systematic biopsy (p = 0.58). The detection rate for targeted biopsy cores (10.4% or 118 of 1,139 cores) was significantly better than for systematic biopsy cores (5.3% or 123 of 2,300 cores, p <0.001). Contrast enhanced targeted biopsy in a patient with cancer was 2.6-fold more likely to detect prostate cancer than systematic US guided biopsy. CONCLUSIONS Contrast enhanced color Doppler targeted biopsy detected as many cancers as systematic biopsy with fewer than half the number of biopsy cores. Although an increase in cancer detection was achieved by combining targeted and systematic techniques in this screening population, contrast enhanced targeted biopsy alone is a reasonable approach for decreasing the number of biopsy cores.

The Influence of Left Renal Vein Entrapment on Outcome After Surgical Varicocele Repair A Color Doppler Sonographic Demonstration

Objective. To evaluate the impact of left renal vein entrapment on outcome after surgical varicocele repair using color Doppler sonography. Methods. Eighty‐four men had varicoceles on color Doppler sonography (2 right sided, 74 left sided, and 8 bilateral), which were diagnosed on the basis of a venous diameter of 3 mm or greater and venous retrograde flow in the pampiniform plexus of veins during the Valsalva maneuver or when changing from a supine to an upright position. Diagnosis of the left renal vein entrapment was based on the following criteria: anteroposterior diameter of greater than 1 cm and peak velocity of less than 15 cm/s for the left renal vein at the mid portion and anteroposterior diameter of less than 0.2 cm and peak velocity of greater than 110 cm/s (or, alternatively, a diameter ratio and peak velocity ratio of >5) for the left renal vein between the aorta and superior mesenteric artery. All patients underwent surgical varicocele repair. In postoperative follow‐up, we compared the presence of left renal vein entrapment with the frequency of varicocele recurrence. Results. Sixteen (19%) of 84 patients had left renal vein entrapment with a left‐sided varicocele. Postoperatively (mean follow‐up ± SD, 19.3 ± 11.7 months), 27 (32.2%) of 84 had varicocele recurrence, including all 16 patients with left renal vein entrapment and 11 (20.1%) of 68 patients without left renal vein entrapment. The varicocele recurrence rate was significantly greater in patients with left renal vein entrapment (P < .001, Fisher exact test). Conclusions. The presence of left renal vein entrapment resulted in a significantly higher varicocele recurrence rate. Patients with varicoceles should routinely be evaluated for the presence of left renal vein entrapment before surgical repair.

Imaging the cardiac blood flow during CPR with EBCT in an animal model

There are open questions concerning the hemodynamics during cardiopulmonary resuscitation (CPR). The purpose was to evaluate a model of the blood flow during CPR in specified anatomic regions. After cardiac arrest, one intubated swine under full intensive care supervision was scanned during CPR using an automated resuscitation device. CT scans were performed with an EBCT in the 50ms modus at eight levels, therefore covering most of the heart and pulmonary vessels. 50ml contrast agent was administered with 10ml/sec and a delay of five seconds to visualize the contrast agent passage through the heart and pulmonary circulation. The gray-value changes in previously specified ROIs were directly correlated with the resuscitation device position in respect to the thorax. The effects of CPR on the blood flow could be visualized dynamically by quantifying the contrast enhancement. The increase of gray values could be estimated with different delays, depending on the anatomical situation. The inflow and outflow dependent on thumper dynamics could be estimated. At the onset of contrast medium inflow, turbulence could be visualized in the right ventricle, which are caused by the inhomogeneous contrast medium distribution. Triggered EBCT during CPR offers the opportunity to study regional blood flow depending on chest compression.

Changes of air-tissue ratio evaluated by EBCT after cardiopulmonary resuscitation (CPR): validation in swine

The purpose was to evaluate changes of the air-tissue ratio (ATR) in previously defined regions of interest after cardiopulmonary resuscitation (CPR) in porcine model. Eight anesthetized and ventilated pigs we scanned in supine position before and 30 minutes after CPR at two different constant PEEP levels (5 cm H2O, 15 cm H2O). Volume scans were obtained using 6 mm slices. The gray values of the lung were divided into steps of 100 HU in order to get access to the changes of ATR. ATR was evaluated in ventral, intermediate and dorsal regions of the lung. CPR for 9 minutes led to an uneven distribution of ventilation. In the ventral region, areas with high ATR increased. Areas with normal ATR decreased. In contrast the dorsal regions with low ATR increased. ATR in the intermediate regions remained almost unchanged. Using the higher PEEP level, areas with normal ATR showed a marked increase accompanied by a decrease of areas with low ATR. After CPR, an uneven distribution of lung aeration was detected. According to the impaired hemodynamics, areas with normal ATR decreased and areas with high and low ATR increased. Using higher PEEP levels improved lung aeration.

Respirator triggering of electron-beam computed tomography (EBCT): differences in dynamic changes between augmented ventilation and controlled mechanical ventilation

The purpose was to evaluate differences in dynamic changes of the lung aeration (air-tissue ratio) between augmented modes of ventilation (AMV) and controlled mechanical ventilation (CMV) in normal subjects. 4 volunteers, ventilated with the different respirator protocols via face mask, were scanned using the EBCT in the 50 ms mode. A software analyzed the respirators digitized pressure and volume signals of two subsequent ventilation phases. Using these values it was possible to calculate the onset of inspiration or expiration of the next respiratory phase. The calculated starting point was then used to trigger the EBCT. The dynamic changes of air- tissue ratios were evaluated in three separate regions: a ventral, an intermediate and a dorsal area. AMV results in increase of air-tissue ratio in the dorsal lung area due to the active contraction of the diaphragm, whereas CMV results in a more pronounced increase in air-tissue ratio of the ventral lung area. This study gives further insight into the dynamic changes of the lungs biomechanics by comparing augmented ventilation and controlled mechanical ventilation in the healthy proband.