Ultrasound for prostate imaging and biopsy

Machine learning based on radiomics features combing B-mode transrectal ultrasound and contrast-enhanced ultrasound to improve peripheral zone prostate cancer detection

PURPOSE

To construct machine learning models based on radiomics features combing conventional transrectal ultrasound (B-mode) and contrast-enhanced ultrasound (CEUS) to improve prostate cancer (PCa) detection in peripheral zone (PZ).

METHODS

A prospective study of 166 men (72 benign, 94 malignant lesions) with targeted biopsy-confirmed pathology who underwent B-mode and CEUS examinations was performed. Risk factors, including age, serum total prostate-specific antigen (tPSA), free PSA (fPSA), f/t PSA, prostate volume and prostate-specific antigen density (PSAD), were collected. Time-intensity curves were obtained using SonoLiver software for all lesions in regions of interest. Four parameters were collected as risk factors: the maximum intensity (IMAX), rise time (RT), time to peak (TTP), and mean transit time (MTT). Radiomics features were extracted from the target lesions from B-mode and CEUS imaging. Multivariable logistic regression analysis was used to construct the model.

RESULTS

A total of 3306 features were extracted from seven categories. Finally, 32 features were screened out from radiomics models. Five models were developed to predict PCa: the B-mode radiomics model (B model), CEUS radiomics model (CEUS model), B-CEUS combined radiomics model (B-CEUS model), risk factors model, and risk factors-radiomics combined model (combined model). Age, PSAD, tPSA, and RT were significant independent predictors in discriminating benign and malignant PZ lesions (P < 0.05). The risk factors model combing these four predictors showed better discrimination in the validation cohort (area under the curve [AUC], 0.84) than the radiomics images (AUC, 0.79 on B model; AUC, 0.78 on CEUS model; AUC, 0.83 on B-CEUS model), and the combined model (AUC: 0.89) achieved the greatest predictive efficacy.

CONCLUSION

The prediction model including B-mode and CEUS radiomics signatures and risk factors represents a promising diagnostic tool for PCa detection in PZ, which may contribute to clinical decision-making.

Evaluation of Prostatic Lesions by Transrectal Ultrasound, Color Doppler, and the Histopathological Correlation

Objective

To evaluate the role of a transrectal ultrasound (TRUS) guided biopsy and a color Doppler test in the detection of prostate cancer in patients with increased serum prostate-specific antigen (PSA) levels and/or an abnormal digital rectal examination (DRE).

Method

A total of 40 cases, ranging in age from 50 to 80 years and showing increased serum PSA levels (4-10 ng/ml) and/or abnormal DRE, were enrolled and underwent TRUS evaluation followed by color Doppler flowmetric studies. A TRUS-guided biopsy was performed in all the cases. The findings were confirmed histopathologically. Data were analyzed using the chi-square test.

Results

Histopathologically, a total of 13 cases (32.5%) were malignant. On TRUS, irregular shape, heterogeneous echotexture loss of differentiation between the peripheral and internal zones, less mean weight of the prostate, and capsular invasion were significantly associated with malignancy. On flowmetry, moderate vascularity and focal asymmetry were significantly associated with malignancy. The combined use of TRUS and color Doppler flowmetry was found to be 100% sensitive and 92.6% specific and had a positive predictive value (PPV) and a negative predictive value (NPV) of 86.7% and 100%, respectively.

Conclusion

TRUS with color Doppler flowmetry was highly sensitive and specific in the detection of prostate malignancy.

Clinical application of contrast enhanced ultrasound to diagnose benign prostatic hyperplasia

Abstract

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/4852383312229155

MRI-targeted prostate biopsy: a review of technique and results

Multiparametric magnetic resonance imaging (mpMRI) is of interest for the diagnosis of clinically significant prostate cancer and mpMRI-targeted biopsies are being used increasingly in clinical practice. Target acquisition is performed using a range of magnet strengths and varying combinations of anatomical and functional sequences. Target identification at the time of biopsy can be carried out in the MRI scanner (in-bore biopsy) or, more commonly, the MRI-target is biopsied under ultrasonographic guidance. Many groups use cognitive or visual registration, whereby the biopsy target is identified on MRI and ultrasonography is subsequently used to direct the needle to the same location. Other groups use registration software to show prebiopsy MRI data on real-time ultrasonography. The reporting of histological results in MRI-targeted biopsy studies varies greatly. The most useful reports compare the detection of clinically significant disease in standard cores versus mpMRI-targeted cores in the same cohort of men, as recommended by the STAndards of Reporting for MRI-Targeted biopsy studies (START) consensus panel. Further evidence is needed before an mpMRI-targeted strategy can be recommended as the standard intervention for men at risk of prostate cancer.

Ultrasound of the prostate

Ultrasound is a widely used imaging modality for evaluation of the prostate. The main topic of diagnostic imaging is an improvement of prostate cancer diagnosis. The current available systematic prostate biopsy is performed only under ultrasound guidance, but new imaging techniques allow prostate cancer visualization and therefore improved detection. Evolving methods such as contrast-enhanced colour Doppler imaging, contrast-specific ultrasound techniques and elastography may dramatically change the role of ultrasound for prostate cancer diagnosis. The purpose of this review is to provide an overview of ultrasound and its different techniques for imaging of the prostate and to discuss current trends and future directions.

GEC/ESTRO-EAU recommendations on temporary brachytherapy using stepping sources for localised prostate cancer

BACKGROUND AND PURPOSE

The aim of this paper is to present the GEC/ESTRO-EAU recommendations for template and transrectal ultrasound (TRUS) guided transperineal temporary interstitial prostate brachytherapy using a high dose rate iridium-192 stepping source and a remote afterloading technique. Experts in prostate brachytherapy developed these recommendations on behalf of the GEC/ESTRO and of the EAU. The paper has been approved by both GEC/ESTRO steering committee members and EAU committee members.

PATIENTS AND METHODS

Interstitial brachytherapy (BT) to organ confined prostate cancer can be applied as a boost treatment in combination with external beam radiation therapy (EBRT) using a proper number of BT fractions in curative intent. Temporary transperineal BT alone or in combination with EBRT are feasible as a palliative/salvage treatment modality because of local recurrence, however, without large clinical experience. The use of temporary BT as a monotherapy is subject of ongoing clinical research.

RESULTS

Recommendations for pre-treatment investigations, patient selection, equipment and facilities, the clinical team, the implant procedure (treatment planning and needle implantation) dose and fractionation, reporting, management of side effects and follow-up are given.

CONCLUSIONS

These recommendations are intended to be technically and advisory in nature, but the ultimate responsibility for the medical decision rests with the treating physician. Although, this paper represents the consensus of an interdisciplinary group of experts, TRUS and template guided temporary transperineal interstitial implants in prostate cancer are a constantly evolving field and the recommendations are subject to modifications as new data become available.

The incidence of prostate cancer in men with prostate specific antigen greater than 4.0 ng/ml: a randomized study of 6 versus 12 core transperineal prostate biopsy

PURPOSE

The prostate cancer detection rate in patients with elevated prostate specific antigen (PSA) increases with extended needle biopsy protocols. Transperineal biopsy under transrectal ultrasound guidance is rarely reported, although notable cancer diagnoses are obtained with this technique. We describe the results of 6 and 12 core transperineal biopsy.

MATERIALS AND METHODS

A total of 214 patients with PSA greater than 4.0 ng/ml were prospectively randomized to undergo 6 or 12 core transperineal biopsy. Each group of 107 patients was comparable in terms of clinical characteristics. The procedure was performed on an outpatient basis using local anesthesia. Specimens were obtained with a fan technique with 2 puncture sites slightly above the rectum (1 per lobe) under transrectal ultrasound guidance. Cores were taken from all peripheral areas, including the far lateral aspect of the prostate.

RESULTS

The overall cancer detection rate was 38% and 51% for 6 and 12 core biopsy, respectively. In patients with PSA between 4.1 and 10 ng/ml the cancer detection rate was 30% and 49% for 6 and 12 core biopsy, respectively.

CONCLUSIONS

The 12 core transperineal prostate biopsy is superior to 6 core biopsy. The technique provides optimal prostate cancer diagnosis. About half of the patients with PSA greater than 4.0 ng/ml and a slightly lower percent with PSA between 4.1 and 10 ng/ml have prostate cancer.