Gomella_edit_new.qxp 25/9/08 10:53 am Page 21
Diagnostic Imaging Approaches to Prostate Cancer
These results are comparable to a similar collaborative study from comparison, this study sought to ensure more accurate prostate
Austria and Philadelphia. Pelzer et al. published a study examining the tissue identification by identifying tissue utilising the combined
utility of adding prostate biopsies targeted to lesions identified with techniques of MRI, magnetic resonance spectroscopic imaging (MRSI)
ultrasound contrast agents to a systematic biopsy approach.
16
Three and transrectal biopsy. In this study, 25 patients were evaluated
hundred and eighty patients with a serum PSA level between 4 and utilising DCE-MRI. Of these 25 patients, 21 had undergone biopsy. In
10ng/ml received an intravenous ultrasound contrast microbubble comparison with normal peripheral-zone tissue, cancerous peripheral-
agent, and contrast-enhanced colour Doppler (CECD) targeted zone tissue demonstrated a greater peak enhancement (126±11 versus
biopsies were performed in areas of peripheral-zone hypervascularity. 118±7; p<0.006), a faster enhancement rate (16.9±8.7 versus 8.8±5.5;
Additional standard systematic 10-core biopsies were then taken by p<0.0008), and a faster washout slope (-0.53±1.4 versus 0.37±1.4).
another blinded examiner. The overall percentage of patients with Stromal benign prostatic hyperplasia was found to have the highest
cancer was 37.6% (143/380). The positive biopsy rates were peak enhancement (132±9) and the fastest enhancement rate (30.3±8)
in comparison with all other tissue types studied (p<0.003). The ability
to further delineate the contrast characteristics of various prostate
Multiple studies have demonstrated
tissues offers much promise in future endeavours to create more
accurate maps of benign and malignant prostate tissue. Potential
increased sensitivity and the
weaknesses of this study include the absence of prostate cancers with
positive predictive value of prostate
Gleason scores greater than seven in the study group and the absence
of evaluation of transitional-zone or central-zone tumours.
biopsy in combination with colour
Doppler imaging. DCE-MRI has also been studied as an alternative to biopsy for the
diagnosis of prostate cancer in the setting of elevated PSA in a
Japanese population. Hara et al.
19
investigated men with an elevated
comparable in the CECD biopsies and systematic biopsies (27.4 and serum PSA level (defined as >2.5ng/ml) and compared DCE-MRI as
27.6%, respectively). The combination of CECD biopsies with standard a detection modality versus 14-core biopsy. DCE-MRI in this study
10-core systematic biopsies increased the overall positive biopsy rate to detected 92.9% of clinically significant prostate cancers with a
37.6%, with the percentage of positive individual positive cores specificity of 96.3%. For men with PSA <10ng/ml, the accuracy was
significantly higher in the CECD-targeted biopsies compared with 80.5%. With further improvements in technology and software, this
standard systematic biopsies (32.6 and 17.9%, respectively; p<0.01). modality holds promise for improved cancer detection and the ability
to perform more selective biopsies in men with elevated PSA.
Elastography
Cancerous prostate tissue can be firm to palpation, with limited Magnetic Resonance Spectroscopic Imaging
elastisticity or compressibility. Elastography of the prostate using TRUS MRSI is an imaging technique that provides a metabolic analysis of
uses this lack of compressibility as a targeting strategy. In a pilot study prostate tissue. The utility of this technique derives from the
from Germany of 404 patients, Konig et al. demonstrated that use of differences in metabolic profile that exist between normal and
realtime elastography in conjunction with standard greyscale TRUS malignant prostate tissue. Specifically, areas of prostatic malignancy
significantly improved prostate cancer detection on needle biopsy.
17
A tend to exhibit higher relative concentrations of choline and reduced
total of 151 men (37.4%) were diagnosed with prostate cancer in this levels of citrate. Zakian et al. investigated whether these differences
study. The sensitivity of standard TRUS biopsy techniques in detecting
prostate cancer was 64.2%, while use of realtime elastography
improved the biopsy sensitivity to 84.2%. While only a pilot study, and
The technique of dynamic contrast-
lacking thorough statistical analysis, this study supports further
investigation examining realtime elastography measurements in
enhanced magnetic resonance imaging
conjunction with standard TRUS prostate biopsy schemes. is designed to take advantage of the
increased vascularity that occurs in and
Magnetic Resonance Imaging
around malignant tumours.
Dynamic Contrast-enhanced Magnetic Resonance Imaging
The technique of dynamic contrast-enhanced magnetic resonance
imaging (DCE-MRI) is designed to take advantage of the increased could be used to predict prostate cancer aggressiveness, i.e. Gleason
vascularity that occurs in and around malignant tumours. The study is score, in a study of 94 men imaged prior to undergoing radical
performed by administering gadolinium-based contrast agent and prostatectomy.
20
Post-operative whole-mount histological analysis was
evaluating the variability in amount and speed of uptake in compared with pre-operative MRSI. Transrectal biopsy correctly
various regions of the prostate. It has been previously shown that predicted Gleason score in 64.2% of the patients. In the 94 patients
cancerous regions in the peripheral zone demonstrate faster evaluated, 239 peripheral-zone lesions were identified. MRSI correctly
enhancement in comparison with normal tissue. A study by Noworolski identified 135 of these lesions and performed best in identifying
et al.
18
sought to further delineate the DCE-MRI imaging characteristics higher-grade lesions (sensitivity 44.4% for Gleason score 3+3 versus
of different types of prostate tissue. In contrast to previous studies that sensitivity 89.5% for Gleason score 4+4). The improved performance
relied exclusively on the results of transrectal prostate biopsy for tissue in higher-grade lesions was due to the positive correlation between
EUROPEAN UROLOGICAL REVIEW 21
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131