Quantitative Computed Tomography Perfusion of Prostate Cancer: Correlation with Whole-Mount Pathology

The Role of [18F]F-Choline PET/CT in the Initial Management and Outcome Prediction of Prostate Cancer: A Real-World Experience from a Multidisciplinary Approach

Initial staging of prostate cancer (PCa) is usually performed with conventional imaging (CI), involving computed tomography (CT) and bone scanning (BS). The aim of this study was to analyze the role of [¹⁸F]F-choline positron emission tomography (PET)/CT in the initial management and outcome prediction of PCa patients by analyzing data from a multidisciplinary approach. We retrospectively analyzed 82 patients who were discussed by the uro-oncology board of the University Hospital of Ferrara for primary staging newly diagnosed PCa (median age 72 (56-86) years; median baseline prostate specific antigen (PSA) equal to 8.73 ng/mL). Patients were divided into three groups based on the imaging performed: group A = only CI; group B = CI + [¹⁸F]F-choline PET/CT; group C = only [¹⁸F]F-choline PET/CT. All data on imaging findings, therapy decisions and patient outcomes were retrieved from hospital information systems. Moreover, we performed a sub-analysis of semiquantitative parameters extracted from [¹⁸F]F-choline PET/CT to search any correlation with patient outcomes. The number of patients included in each group was 35, 35 and 12, respectively. Patients with higher values of initial PSA were subjected to CI + PET/CT (p = 0.005). Moreover, the use of [¹⁸F]F-choline PET/CT was more frequent in patients with higher Gleason score (GS) or ISUP grade (p = 0.013). The type of treatment performed (surgery n = 33; radiation therapy n = 22; surveillance n = 6; multimodality therapy n = 6; systemic therapy n = 13; not available n = 2) did not show any relationship with the modality adopted to stage the disease. [¹⁸F]F-choline PET/CT induced a change of planned therapy in 5/35 patients in group B (14.3%). Moreover, patients investigated with [¹⁸F]F-choline PET/CT alone demonstrated longer biochemical recurrence (BCR)-free survival (30.8 months) in comparison to patients of groups A and B (15.5 and 23.5 months, respectively, p = 0.006), probably due to a more accurate selection of primary treatment. Finally, total lesion choline kinase activity (TLCKA) of the primary lesion, calculated by multiplying metabolic tumor volume and mean standardized uptake value (SUVmean), was able to more effectively discriminate patients who had recurrence after therapy compared to those without (p = 0.03). In our real-world experience [¹⁸F]F-choline PET/CT as a tool for the initial management of PCa had a relevant impact in terms of therapy selection and was associated with longer BCR-free survival. Moreover, TLCKA of the primary lesion looks a promising parameter for predicting recurrence after curative therapy.

Perfusion change in benign prostatic hyperplasia before and after castration in a canine model: Contrast enhanced ultrasonography and CT perfusion study

Hormonal and vascular changes affecting the canine prostate after castration were investigated to identify the effects of hormones and perfusion on the development of benign prostatic hyperplasia (BPH). Concentrations of serum testosterone and estrogen and intraprostatic dihydrotestosterone (DHT) were compared between 5 normal dogs, 6 dogs with mild BPH, and 6 dogs with marked BPH. In addition, prostatic perfusion using contrast-enhanced ultrasonography (CEUS) and CT perfusion (CTP), as well as CT volumes of the prostates were compared. The changes in these values following castration were assessed in 6 dogs with marked BPH. CEUS revealed significantly slower prostatic arterial inflow and relatively faster venous outflow in BPH versus normal prostate. Permeability and blood volume were not significantly different between the groups via CTP. Intraprostatic DHT level was higher in BPH than in normal prostate and decreased significantly following castration, which was accompanied by a rapid decrease in prostatic volume. On CEUS, arterial inflow to the prostate significantly decreased following castration. Blood volume within the prostate decreased significantly by day 60 following castration. Permeability increased significantly during the early phase after castration; however, by day 60 post-castration, all perfusion parameters decreased significantly. Perfusion changes including venous parameters measured by CEUS and blood volume changes measured by CTP, however, did not support the backflow theory postulating that BPH is induced by vascular changes from congested testes. The major etiology for the development of BPH is attributed to be increased levels of DHT rather than vascular changes.

4D perfusion CT of prostate cancer for image-guided radiotherapy planning: A proof of concept study

Purpose

Advanced forms of prostate cancer (PCa) radiotherapy with either external beam therapy or brachytherapy delivery techniques aim for a focal boost and thus require accurate lesion localization and lesion segmentation for subsequent treatment planning. This study prospectively evaluated dynamic contrast-enhanced computed tomography (DCE-CT) for the detection of prostate cancer lesions in the peripheral zone (PZ) using qualitative and quantitative image analysis compared to multiparametric magnet resonance imaging (mpMRI) of the prostate.

Methods

With local ethics committee approval, 14 patients (mean age, 67 years; range, 57–78 years; PSA, mean 8.1 ng/ml; range, 3.5–26.0) underwent DCE-CT, as well as mpMRI of the prostate, including standard T2, diffusion-weighted imaging (DWI), and DCE-MRI sequences followed by transrectal in-bore MRI-guided prostate biopsy. Maximum intensity projections (MIP) and DCE-CT perfusion parameters (CTP) were compared between healthy and malignant tissue. Two radiologists independently rated image quality and the tumor lesion delineation quality of PCa using a five-point ordinal scale. MIP and CTP were compared using visual grading characteristics (VGC) and receiver operating characteristics (ROC)/area under the curve (AUC) analysis.

Results

The PCa detection rate ranged between 57 to 79% for the two readers for DCE-CT and was 92% for DCE-MRI. DCE-CT perfusion parameters in PCa tissue in the PZ were significantly different compared to regular prostate tissue and benign lesions. Image quality and lesion visibility were comparable between DCE-CT and DCE-MRI (VGC: AUC 0.612 and 0.651, p>0.05).

Conclusion

Our preliminary results suggest that it is feasible to use DCE-CT for identification and visualization, and subsequent segmentation for focal radiotherapy approaches to PCa.

Assessment of prostate cancer with integrated CT-perfusion using a sector-wise approach

OBJECTIVE

The role of computed tomography perfusion (CTP) in characterizing primary prostate cancer (PCa) is not definitely known. The aim of the present study was to investigate the relationship between CTP parameters and histopathological features of PCa tissue, using a sector-wise approach.

MATERIAL AND METHODS

Fifty-one patients with biopsy-proven PCa underwent prospectively a CTP scan prior to radical prostatectomy. Blood flow (BF), mean blood volume (BV) and mean transit time (MTT) were calculated, with the prostate being divided into eight sectors. Corresponding sector-wise histopathological analysis of whole-mount prostatectomy specimens was performed to determine tumoral area (mm²), mean microvessel density (MVD), Gleason patterns (primary, secondary) and total Gleason score. Spearman's rank correlation coefficient was used to analyze the association between CTP and histopathological parameters.

RESULTS

BF correlated weakly with tumoral area [ρs coefficient (p-value): 0.25 (0.00)] and MVD [ρs coefficient (p-value): 0.23 (0.00)]. No valuable correlation was found between CTP parameters and primary and secondary Gleason patterns, whereas total Gleason score was weakly correlated with BV [ρs coefficient (p-value): 0.22 (0.00)] and MTT [ρs coefficient (p-value): 0.25 (0.00)].

CONCLUSION

BF correlates weakly with size and vascularity of PCa. There is a need for further studies to elucidate the association between CTP parameters and other histopathological parameters.

Computed Tomography Perfusion of Prostate Cancer: Diagnostic Value of Quantitative Analysis

OBJECTIVE

The aim of the study was to assess the diagnostic value of computed tomography perfusion (CTp) of prostate in distinguishing between normal tissue and malignant lesion by using quantitative threshold values of CTp parameters.

MATERIALS AND METHODS

Sixty-one consecutive men with indication for radical prostatectomy were prospectively enrolled. All patients were intravenously injected with 80-mL bolus of nonionic iodinated contrast medium during cine-mode acquisition protocol. Perfusion data sets were analyzed by a dedicated software system and values for each of the 4 CTp parameters (blood volume, blood flow, mean transit time, and permeability surface-area product measurements) were recorded. Receiver operating characteristic curves were calculated to find which CTp parameter and which cutoff value might reveal the best diagnostic accuracy. Histopathology was used as reference standard.

RESULTS

Statistical correlation between radiological and pathological results was performed on 48 patients using 3456 segmented squares. Blood volume and permeability surface revealed the best diagnostic accuracy for differentiating between malignant and benign squares, with cutoff values of 6.1 and 16.5, respectively, and a sensitivity of 84.8% and 81.8%, respectively. All parameters showed also a high negative predictive value: 97.1% for blood volume and 95.4% for permeability surface.

CONCLUSIONS

Blood volume and permeability surface are the 2 CTp parameters with the highest diagnostic accuracy in differentiating between normal tissue and prostatic neoplasia. Due to the extremely high negative predictive value, they are particularly valuable in excluding the presence of cancer and thus resulting potentially useful in assessing cancer response to adjuvant therapy.

Is primary tumor detectable in prostatic carcinoma at routine contrast-enhanced CT?

OBJECTIVES

To determine if prostatic carcinoma (PCa) is detectable at routine contrast-enhanced CT (CECT).

MATERIALS AND METHODS

With institutional review board approval, 63 consecutive PCa patients underwent CECT before therapy. Two blinded radiologists assessed for rounded focal enhancing peripheral zone nodules. Diagnostic accuracy and inter-observer agreement were compared by Gleason Score (GS).

RESULTS

Overall sensitivity was 63-76% with moderate agreement, K=0.42. The false-positive rate was 15%. Sensitivities and agreement for GS 9-10, 7-8 and 6 PCa were 84-91%, 73-84%, 41-71%, (P=.023 and .001) and K=(0.72, 0.69, 0.23).

CONCLUSIONS

CECT has good sensitivity for detecting GS ≥7 PCa with substantial agreement and a low false-positive rate.

Correlation between CT perfusion and clinico-pathological features in prostate cancer: a prospective study

Background

The aim of the study was to assess the correlation between computed tomography perfusion (PCT) parameters and PSA levels, Gleason score, and pTNM stage in patients with prostate cancer (PCa).

Material/Methods

One hundred twenty-five patients with localized PCa were prospectively enrolled in the study. All patients were diagnosed due to suspicious prostate findings and elevated PSA serum levels and underwent PCT followed by core biopsy and radical prostatectomy. Blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability-surface (PS) area product were computed in the suspected PCa area and normal prostatic tissue. Core biopsy followed by prostatectomy was performed 2–4 weeks after PCT. Correlation between PCT findings and PSA levels, Gleason score, and pTNM stage were analyzed.

Results

The mean age of patients was 64 years. All patients had elevated PSA levels (mean value 6.2 ng/ml). Nineteen patients (15.9%) were at low risk of recurrence, 91 (76.5%) were at moderate risk, and 9 (7.6%) were at high risk according to National Comprehensive Cancer Network criteria. PCa was visible on PCT as focal peripheral CT enhancement in 119 out of 125 patients (sensitivity 95.2%). Significant correlations between BV, BF, and PS values and PSA level were found (p<0.05), as well as a trend for difference between BV, BF, and PS in poorly and moderately differentiated tumors (according to Gleason score) in comparison with highly differentiated PCa (p<0.08). The analysis also revealed a correlation between mean perfusion values and BV, MTT, PS, and pTNM cancer stage (p<0.04).

Conclusions

Our study suggests that in low- and intermediate- risk patients, PCT parameters correlate with PSA values, Gleason score, and pTNM stage and can be useful for initial tumor staging.

Perfusion CT is a valuable diagnostic method for prostate cancer: a prospective study of 94 patients

Purpose

The aim of this study is to assess the usefulness of perfusion computer tomography (pCT) in prostate cancer (PCa) diagnostics.

Materials and Methods

94 patients with biopsy-proven PCa were enrolled in the study. Dynamic pCT of the prostate gland was performed for 50 seconds after an intravenous injection of contrast medium. Blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface area product (PS) were computed in the suspected PCa area and in normal prostatic tissue.

Results

PCa was visible in pCT in 90 of the 94 examined patients as a focal peripheral CT enhancement. When PCa was located in the peripheral zone (PZ), it was visible on perfusion maps, mostly showing an early peak followed by wash-out. The average values of all perfusion parameters were higher for tumour than for normal prostate tissue (p < 0.000). BV and BF were dependent on tumour grade expressed by the Gleason score (GS). All PCa cases were divided into groups, according to histological grade, as low (GS ≤ 6), medium (GS = 7), and high (GS > 7). In high-grade PCa, the mean BF value was significantly higher (p = 0.001) than the mean value of BF low- and medium-grade PCa (p = 0.011). Similar results were obtained regarding the mean values of BV; the more aggressive the cancer grade, the higher the mean BV value (p = 0.04).

Conclusion

CT quantitative perfusion imaging allows PCa to be distinguished from normal prostate tissue. The highest values for BF and BV were observed in the most aggressive PCa grade.

Feasibility study of CT perfusion imaging for prostate carcinoma

OBJECTIVE

The aim of this feasibility study was to obtain initial data with which to assess the efficiency of perfusion CT imaging (CTpI) and to compare this with magnetic resonance imaging (MRI) in the diagnosis of prostate carcinoma.

MATERIALS AND METHODS

This prospective study involved 25 patients with prostate carcinoma undergoing MRI and CTpI. All analyses were performed on T2-weighted images (T2WI), apparent diffusion coefficient (ADC) maps, diffusion-weighted images (DWI) and CTp images. We compared the performance of T2WI combined with DWI and CTp alone. The study was approved by the local ethics committee, and written informed consent was obtained from all patients.

RESULTS

Tumours were present in 87 areas according to the histopathological results. The diagnostic performance of the T2WI+DWI+CTpI combination was significantly better than that of T2WI alone for prostate carcinoma (P < 0.001). The diagnostic value of CTpI was similar to that of T2WI+DWI in combination. There were statistically significant differences in the blood flow and permeability surface values between prostate carcinoma and background prostate on CTp images.

CONCLUSION

CTp may be a valuable tool for detecting prostate carcinoma and may be preferred in cases where MRI is contraindicated. If this technique is combined with T2WI and DWI, its diagnostic value is enhanced.

KEY POINTS

Perfusion CT is a helpful technique for prostate carcinoma diagnosis. •Colour maps allow easy and rapid visual assessment of the functional changes. Colour maps of prostate carcinoma provide information about in vivo tumoral vascularity. CTp images may be added into routine radiological examinations. CTp provides guidance for histopathological correlation if biopsy is scheduled.

Prostate cancer detection and diagnosis: the role of MR and its comparison with other diagnostic modalities--a radiologist's perspective

It is now universally recognized that many prostate cancers are over-diagnosed and over-treated. The European Randomized Study of Screening for Prostate Cancer from 2009 evidenced that, to save one man from death from prostate cancer, over 1400 men need to be screened, and 48 need to undergo treatment. The detection of prostate cancer is traditionally based on digital rectal examination (DRE) and the measurement of serum prostate-specific antigen (PSA), followed by ultrasound-guided biopsy. The primary role of imaging for the detection and diagnosis of prostate cancer has been transrectal ultrasound (TRUS) guidance during biopsy. Traditionally, MRI has been used primarily for the staging of disease in men with biopsy-proven cancer. It has a well-established role in the detection of T3 disease, planning of radiation therapy, especially three-dimensional conformal or intensity-modulated external beam radiation therapy, and planning and guiding of interstitial seed implant or brachytherapy. New advances have now established that prostate MRI can accurately characterize focal lesions within the gland, an ability that has led to new opportunities for improved cancer detection and guidance for biopsy. Two new approaches to prostate biopsy are under investigation. Both use pre-biopsy MRI to define potential targets for sampling, and the biopsy is performed either with direct real-time MR guidance (in-bore) or MR fusion/registration with TRUS images (out-of-bore). In-bore and out-of-bore MRI-guided prostate biopsies have the advantage of using the MR target definition for the accurate localization and sampling of targets or suspicious lesions. The out-of-bore method uses combined MRI/TRUS with fusion software that provides target localization and increases the sampling accuracy of TRUS-guided biopsies by integrating prostate MRI information with TRUS. Newer parameters for each imaging modality, such as sonoelastography or shear wave elastography, contrast-enhanced ultrasound and MRI elastography, show promise to further enrich datasets.

Prostate tissue characterization/classification in 144 patient population using wavelet and higher order spectra features from transrectal ultrasound images

In this work, we have proposed an on-line computer-aided diagnostic system called "UroImage" that classifies a Transrectal Ultrasound (TRUS) image into cancerous or non-cancerous with the help of non-linear Higher Order Spectra (HOS) features and Discrete Wavelet Transform (DWT) coefficients. The UroImage system consists of an on-line system where five significant features (one DWT-based feature and four HOS-based features) are extracted from the test image. These on-line features are transformed by the classifier parameters obtained using the training dataset to determine the class. We trained and tested six classifiers. The dataset used for evaluation had 144 TRUS images which were split into training and testing sets. Three-fold and ten-fold cross-validation protocols were adopted for training and estimating the accuracy of the classifiers. The ground truth used for training was obtained using the biopsy results. Among the six classifiers, using 10-fold cross-validation technique, Support Vector Machine and Fuzzy Sugeno classifiers presented the best classification accuracy of 97.9% with equally high values for sensitivity, specificity and positive predictive value. Our proposed automated system, which achieved more than 95% values for all the performance measures, can be an adjunct tool to provide an initial diagnosis for the identification of patients with prostate cancer. The technique, however, is limited by the limitations of 2D ultrasound guided biopsy, and we intend to improve our technique by using 3D TRUS images in the future.

Neoangiogenesis in prostate cancer

Prostate cancer has the second highest incidence among malignant tumors in men in Poland, and the first in the USA. Currently, medical reports state that incidentally non-diagnosed prostate cancer is present in about 30–46% of men over the age of fifty.

Tumor angiogenesis has significant implications in the diagnosis and treatment of various solid tumors. With fast, multi-slice CT scanners and their ability of qualitative and quantitative analysis of tumor angiogenesis, CT perfusion has been the subject of extensive investigation in the past twenty years.

Tumor angiogenesis is characterized morphologically by an increase in the number of blood vessels including new capillaries, capillary sprouts, non-endothelialized capillaries and arterio-venous shunts.

It is stated in the literature that pathological vessel density within prostate cancer is one of the factors determining the extent of the tumor – whether the tumor is confined to the prostate gland or extends beyond the prostate capsule. It was proved that the density of pathological vessels is higher in patients with tumors beyond the prostate capsule.

Initial publications show validity of functional imaging, such as perfusion CT in prostate cancer staging before a surgical procedure. This examination can also show excessive density of pathological vessels within the prostate gland according to increased blood volume (BV) and blood flow (BF) and pathologically increased permeability of the vessels (PS). Vessel abnormalities in the examined area are also indicated by shorter mean transit time (MTT).

Blood flow and oxygenation status of prostate cancers

Hypoxia is a characteristic of many solid tumors, can lead to the development of an aggressive phenotype and acquired treatment resistance, and is an independent, adverse prognostic indicator. In this literature review, we show that hypoxia is also a typical feature in prostate cancer (PC), the most commonly diagnosed cancer among men in most western countries. Data on blood flow (a major determinant of oxygenation status in malignancies) and on the oxygenation status (as assessed by O(2)-sensitive electrodes) are presented. Where possible, data on prostate cancers are compared to normal prostate (NP) tissue and benign prostate hyperplasia (BPH). The average blood flow rate in NP is 0.21 vs. 0.28 mL/g/min in BPH. Blood flow in PC is approximately three times higher than in NP (mean flow: 0.64 mL/g/min) and shows pronounced intra- and inter-tumor variability. Despite relatively high flow rates in PC, the overall mean pO(2) in cancers is 6 mmHg compared to 26 mmHg in NP. As was the case with blood flow, tissue oxygenation was extremely heterogeneous with no clear dependency on a series of tumor (Gleason score, clinical size, androgen deprivation) and patient characteristics (serum PSA levels, age).

Whole tumour quantitative measurement of first-pass perfusion of oesophageal squamous cell carcinoma using 64-row multidetector computed tomography: correlation with microvessel density

PURPOSE

To assess correlations between whole tumour first-pass perfusion parameters obtained with 64-row multidetector computed tomography (MDCT), and microvessel density (MVD) in oesophageal squamous cell carcinoma.

MATERIALS AND METHODS

Thirty-one consecutive patients with surgically confirmed oesophageal squamous cell carcinomas were enrolled into our study. All the patients underwent whole tumour first-pass perfusion scan with 64-row MDCT. Perfusion parameters, including perfusion (PF), peak enhanced density (PED), blood volume (BV), and time to peak (TTP) were measured using Philips perfusion software. Postoperative tumour specimens were assessed for MVD. Pearson correlation coefficient tests were performed to determine correlations between each perfusion parameter and MVD.

RESULTS

Mean values for PF, PED, BV and TTP of the whole tumour were 28.85 ± 20.29 ml/min/ml, 23.16 ± 8.09 HU, 12.13 ± 5.21 ml/100g, and 35.05 ± 13.85 s, respectively. Mean MVD in whole tumour at magnification (×200) was 15.75 ± 4.34 microvessel/tumour sample (vessels/0.723 mm(2)). PED and BV were correlated with MVD (r=0.651 and r=0.977, respectively, all p<0.05). However, PF and TTP were not correlated with MVD (r=0.070 and r=0.100, respectively, all p>0.05).

CONCLUSION

The BV value of first-pass perfusion CT could reflect MVD in oesophageal squamous cell carcinoma, and can be an indicator for evaluating the tumour angiogenesis.

Quantitative assessment of first-pass perfusion of oesophageal squamous cell carcinoma using 64-section MDCT: initial observation

AIM

To clarify the feasibility of first-pass perfusion computed tomography (CT) using 64-section multidetector CT (MDCT) for tumour microcirculation of oesophageal squamous cell carcinoma, and to determine the threshold value of first-pass perfusion values for the discrimination between the microcirculation of the tumour and normal oesophagus.

MATERIALS AND METHODS

Forty-one patients with pathologically confirmed oesophageal squamous cell carcinomas served as the test group, which was subdivided into subgroups according to the pathological grades or the status of lymph node metastasis. Forty patients with a normal oesophagus served as controls. All patients underwent volume-based perfusion imaging using 64-section MDCT. Perfusion parameters including perfusion (PF), peak enhancement (PE), blood volume (BV), and time to peak (TTP) were measured. The differences in perfusion parameters between the test and control groups, and between the subgroups were compared statistically. The cut-off values were obtained statistically to discriminate microcirculation between the tumour and normal oesophagus.

RESULTS

Mean values for the BV and TTP of the tumour were 12.57+/-5.15 ml/100g (range 2.9-25.6) and 33.71+/-14.12 s (range 6-65), respectively. Mean values for the BV and TTP of the normal oesophagus were 4.33+/-3.6 ml/100 g (range 0.3-11.7) and 24.15+/-11.67 s (range 6-48), respectively. The BV and TTP were statistically higher in the test group than in the control group (p<0.05), but no statistical differences in the PF and PE were found between the test and control groups (p>0.05). There were no statistical differences in all parameters between the subgroups of pathological grades, and between subgroups with and without lymph-node metastases (p>0.05). For the discrimination of microcirculation of the tumour from that of the normal oesophagus, a threshold BV value of 6.65 ml/100g was determined and achieved a sensitivity of 95.1%, and specificity of 90%.

CONCLUSION

The first-pass perfusion technique using 64-section MDCT could be valuable to assess the microcirculation of oesophageal squamous cell carcinomas.

Imaging of prostate cancer

The role of imaging in the diagnosis and management of prostate is reviewed. Transrectal ultrasonography, which can be used to guide biopsy, is most frequently used imaging technique in cancer detection. For determining the extent of disease, CT and MR imaging are the most commonly used modalities; bone scintigraphy and positron emission tomography have roles only in advanced disease. Currently, the role of imaging in prostate cancer is evolving to improve disease detection and staging, to determine the aggressiveness of disease, and to predict outcomes in different patient populations