Doppler der Prostata

vergrößerte Prostata: Beschwerden & Behandlungsmethoden

Diät für Prostata-Verkalkung

New technical and clinical developments of sonography and magnetic resonance imaging include improved detection, localization and staging as well as active surveillance of prostate cancer. Multiparametric MRI can best answer these typical clinical questions. However, ultrasound elastography seems to be suitable for the detection of significant prostate cancer Doppler der Prostata well. Bildgebung der Prostata Doppler der Prostata Ein Update.

Neue technische und klinische Entwicklungen auf dem Gebiet der Ultraschalldiagnostik und auf dem Gebiet der Magnetresonanztomografie haben die Detektion, Lokalisation und Staging sowie die aktive Überwachung des Prostatakarzinoms stark verbessert. Die Ultraschallelastografie scheint ebenfalls für den Nachweis signifikanter Karzinome geeignet zu sein.

Prostate cancer is the most common cancer in Germany and the third Doppler der Prostata common cancer resulting in death in men [ 1 ]. Ultrasound and magnetic resonance imaging have developed very dynamically in recent years for the diagnosis of prostate cancer. These new technical and clinical developments are evaluated in the following after a short introduction regarding suitability for the detection, localization and staging and active monitoring of prostate cancer.

The prostate is accessible with ultrasound. Transrectal ultrasound TRUS performed with endocavitary ultrasound probes provides very precise images of the prostate. The strength of the Doppler der Prostata sound waves is coded in brightness mode B-mode as a grayscale image.

The Doppler effect of moving reflective objects blood is utilized for color-coded Doppler sonography. The Doppler signals are registered by pulsed wave Doppler PW Doppler and the flow direction and rate are determined from the Doppler shift discrepancy between frequency of echo and ultrasonic pulse. These are color-coded and superimposed on the B-mode image. This makes it difficult to detect and locate the prostate cancer. However, it could be shown that the positive predictive value regarding the presence of prostate cancer is elevated when signs of increased vascularization can be detected on color-coded Doppler sonography [ Fig.

Targeted specimen collection from these areas can be performed in these cases in addition to systematic biopsy in accordance with the S3 guideline S3 guideline Rather the prostate volume can be calculated with TRUS and the systematic extraction of core biopsies can Doppler der Prostata guided by imaging. Elastography makes it possible to evaluate the elasticity and stiffness of tissue. In principle, there are two methods: conventional ultrasound strain elastography and ultrasound shear wave elastography.

In the case of strain elastography, the tissue to be examined is compressed by the examiner using the ultrasound probe. The comparison of ultrasound Doppler der Prostata before and after compression makes it possible to make conclusions about the stiffness of the tissue based on the degree of deformation. Adequate application of compression and the interpretation of the color-coded Doppler der Prostata in real time are difficult to standardize Doppler der Prostata yield heterogeneous, examiner-dependent results.

Another method is shear wave elastography in which the tissue is not compressed. Rather the shear waves are applied directly by the ultrasound probe and then disperse into the tissue shear wave propagation. The stiffness of the tissue is calculated based on the propagation speed of the shear waves in the tissue. The main advantage of Doppler der Prostata method is the high intraindividual and interindividual reproducibility [ 3 ].

In general, prostate cancer Doppler der Prostata characterized by increased stiffness compared to normal tissue [ Fig.

However, areas with prostatitis, fibrosis, atrophy, or with benign prostate hyperplasia can also be associated with increased stiffness on ultrasound elastography. The resulting difficulty differentiating from prostate cancer leads to false-positive findings.

False-negative elastography findings can be due to the architecture pattern of the Doppler der Prostata prostate cancer [ 4 ]. However, if the prostate cancer is comprised of tumor cells that are close together, this results in stiff tissue and better detection on ultrasound elastography [ Fig.

Since it was also able to be shown with this study that the combination of both methods detects more cancers than targeted or systematic biopsy alone, ultrasound elastography should only be used for the detection of prostate cancer in combination with systematic biopsy.

It was also Doppler der Prostata in this study that 34 patients with a significant prostate cancer could only be detected by ultrasound elastography [ 7 ]. This means that negative elastography rules out high-grade prostate cancer with high probability. These results indicate that elastography has great potential to be helpful for select patients undergoing active monitoring.

In regression analysis, it could also be shown that positive elastography is an independent marker for high-grade prostate cancer [ 8 ]. For determining the location of the prostate cancer with the help of ultrasound elastography, it was shown that the accuracy depends on the size and volume of the cancer [ 9 ].

Due to the insufficient sensitivity for detecting an extracapsular growth, the method should not be routinely used for staging. However, these areas in particular are clinically relevant since approx. For various issues, ultrasound can be enhanced Doppler der Prostata the use of ultrasound contrast agents.

Ultrasound contrast agents are comprised of gas-filled microbubbles. The microbubbles begin Doppler der Prostata oscillate in the ultrasound field and these nonlinear oscillations can be effectively differentiated from the linear signals of the tissue.

This then results in increased contrast of highly vascular prostate Doppler der Prostata compared to minimally vascularized areas [ 12 ].

The main disadvantage of this method in our opinion is the relatively short examination time since in particular the wash-in phase of the contrast is greatest between highly vascularized prostate cancer and less vascularized normal prostate tissue.

Since this phase is generally not longer than 10 seconds, the examination of the entire prostate is very difficult. In practice, usually only the areas that appear suspicious on B-mode images Doppler der Prostata be further clarified. These results suggest that contrast-enhanced ultrasound is not suitable for detection. We do not know of current data regarding localization, staging and active monitoring with Doppler der Prostata help of contrast-enhanced ultrasound.

However, it is obvious that Doppler der Prostata insufficient detection accuracy is probably also associated with an insufficient localization accuracy and this entails high unreliability regarding undetected significant prostate cancers.

Therefore, contrast-enhanced ultrasound should not be used for localization and staging and for selecting suitable patients for active monitoring according Doppler der Prostata current data. The raw TRUS data are processed by characterization algorithms developed specifically for this purpose and a three-dimensional image of the prostate is then generated.

Suspicious areas are marked in color [ 14 ]. In the past Doppler der Prostata positive data for HistoScanning TM was published by one center. However, current publications provide different data. The comparison of the detection rate of HistoScanning TM with the results of systematic perineal biopsy yielded comparable results. A further study with evaluated patients used HistoScanning TM for prediction accuracy of a subsequent sextant biopsy.

A diagnostic accuracy of HistoScanning TM for the detection of prostate cancer of 0. Therefore, this method does not seem suitable for staging [ 15 ]. The cancer volume determined with HistoScanning TM did not coincide with the actual volume in the prostatectomy specimen [ 17 ]. To our knowledge, no studies regarding the suitability of HistoScanning TM for active monitoring have been published yet. However, the insufficient detection accuracy and the lack of ability to determine tumor volume indicate that significant prostate cancers cannot be reliably ruled out with HistoScanning TM.

These results were able to be confirmed in another study with 20 patients. A comparison of the results of targeted biopsy of suspicious areas and systematic biopsy has not yet been published.

Due to the low number of studies published to date, a final evaluation of this method is currently not possible in our opinion. T2-weighted imaging provides the most important anatomical information in mpMRI. Prostate cancer Doppler der Prostata a low signal in T2 weighting.

The quantification of the T2 signal intensity via dedicated mapping sequences was examined in initial studies of small cohorts with respect to feasibility [ 21 Doppler der Prostata.

There are currently no larger prospective studies for detecting and localizing prostate cancer with this method. DWI measures Brownian molecular motion of water molecules. In MRI the motion of the hydrogen in water molecules Doppler der Prostata be represented by the signal loss between two refocusing pulses [ 22 ].

To eliminate the T2 shine-through effect, the apparent diffusion coefficient ADC is Doppler der Prostata from the signal intensities of 2 or more diffusion weights. In general due to the higher cell density and the increased intracellular and intercellular proteins, prostate cancer has increased diffusion restriction compared to normal prostate tissue [ 23 ]. For this reason, prostate cancer is typically characterized Doppler der Prostata a lower Doppler der Prostata value than normal tissue and correspondingly increased signal intensities on diffusion-weighted images.

DCE-MRI continuously measures the signal intensities in prostate tissue after administration of an intravenous bolus of a non-specific Doppler der Prostata gadolinium-based contrast agent. In comparison to normal tissue, prostate cancer is characterized in general by an earlier start of the signal increase, a steeper increase of the signal intensity time curve, a higher absolute signal intensity level, and a more significant drop in signal intensities Doppler der Prostata the further time course [ 24 ].

These signal intensity time curves form the foundation for all modeling in pharmacokinetic models. The most common pharmacokinetic model is the open two-compartment model according to Tofts with the parameters transfer constant K transrate constant k epand extracellular extravascular space EES [ 25 ]. In contrast, 1 H-MRS allows noninvasive evaluation of the chemical composition of the prostate. The received frequency spectrum is disassembled via Fourier transformation into the individual frequencies which are shown in parts per million ppm of the resonance Doppler der Prostata of trimethylsilyl propionate on the abscissa with the corresponding signal intensity on the ordinate [ 26 ].

The important metabolites for prostate Doppler der Prostata are choline at 3. The main clinical Doppler der Prostata of mpMRI of the prostate in Germany is the detection of cancer.

Adding 1 H-MRS did not result in an increase in the diagnostic accuracy. The diagnostic detection accuracy of all significant and not significant prostate cancers was 0. Compared to conventional urological diagnosis palpation finding, Doppler der Prostata PSA value, and prostate volumeDoppler der Prostata was able to be shown that the diagnostic accuracy for the detection of significant prostate cancers increased from Doppler der Prostata. This result was independent of the field strength of the MRI unit 1.

MRI-guided biopsy of the prostate performed at specialized centers was used in the past for histology in areas suspicious on MRI [ 29 ]. It was able to be shown that this approach detected It was able to be shown that both strategies incur approximately the same costs [ 31 ]. In addition, the MRI strategy results in a reduction of the overdiagnosis and overtreatment of low-risk prostate cancers and Doppler der Prostata in improved quality of life compared to the TRUS strategy [ 31 ].

In principle, the last-mentioned method includes two technical approaches. The approach offered by most providers is the rigid fusion of MRI and ultrasound images. However, this type of fusion cannot anticipate any deformation of the prostate caused by the ultrasound probe.

In contrast, newer systems provide elastic fusion and minimize Doppler der Prostata problem. The largest study on fusion biopsy published to date prospectively examined patients [ 32 ].

Moreover, it was shown that for every high-risk prostate cancer additionally found with systematic biopsy patients had to undergo both systematic and targeted biopsy [ 32 ].

Exact localization is required for proper staging. The corresponding diagnostic accuracies are between 0.