Tag Archive for: ultrasonography

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Article of the week: Ultrasound characteristics of regions identified as suspicious by MRI predict the likelihood of clinically significant cancer on MRI–ultrasound fusion‐targeted biopsy

Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an editorial written by a prominent member of the urological community, and a video made by the authors. These are intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation. 

If you only have time to read one article this week, it should be this one.

 

The ultrasound characteristics of regions identified as suspicious by magnetic resonance imaging (MRI) predict the likelihood of clinically significant cancer on MRI–ultrasound fusion‐targeted biopsy

Benjamin Press*, Andrew B. Rosenkrantz, Richard Huang and Samir S. Taneja§ 
 
*Rutgers New Jersey Medical School, Newark, NJ, Department of Radiology, Department of Urology, and §Departments of Urology and Radiology, NYU Langone Health, New York, NY, USA
 

Abstract

Objective

To determine whether the presence of an ultrasound hypoechoic region at the site of a region of interest (ROI) on magnetic resonance imaging (MRI) results in improved prostate cancer (PCa) detection and predicts clinically significant PCa on MRI–ultrasonography fusion‐targeted prostate biopsy (MRF‐TB).

Materials and Methods

Between July 2011 and June 2017, 1058 men who underwent MRF‐TB, with or without systematic biopsy, by a single surgeon were prospectively entered into an institutional review board‐approved database. Each MRI ROI was identified and scored for suspicion by a single radiologist, and was prospectively evaluated for presence of a hypoechoic region at the site by the surgeon and graded as 0, 1 or 2, representing none, a poorly demarcated ROI‐HyR, or a well demarcated ROI‐HyR, respectively. The interaction of MRI suspicion score (mSS) and ultrasonography grade (USG), and the prediction of cancer detection rate by USG, were evaluated through univariate and multivariate analysis.

Results

For 672 men, the overall and Gleason score (GS) ≥7 cancer detection rates were 61.2% and 39.6%, respectively. The cancer detection rates for USGs 0, 1 and 2 were 46.2%, 58.6% and 76.0% (P < 0.001) for any cancer, and 18.7%, 35.2% and 61.1% (P < 0.001) for GS ≥7 cancer, respectively. For MRF‐TB only, the GS ≥7 cancer detection rates for USG 0, 1 and 2 were 12.8%, 25.7% and 52.0%, respectively (P < 0.001). On univariate analysis, in men with mSS 2–4, USG was predictive of GS ≥7 cancer detection rate. Multivariable regression analysis showed that USG, prostate‐specific antigen density and mSS were predictive of GS ≥7 PCa on MRF‐TB.

Conclusions

Ultrasonography findings at the site of an MRI ROI independently predict the likelihood of GS ≥7 PCa, as men with a well‐demarcated ROI‐HyR at the time of MRF‐TB have a higher risk than men without.

Residents’ podcast: Implementation of mpMRI technology for evaluation of PCa in the clinic

Giulia Lane M.D. is a Fellow in Neuro-urology and Pelvic Reconstruction in the Department of Urology at the University of Michigan; Kyle Johnson is a Urology Resident in the same department.

In this podcast they discuss the following BJUI Article of the Month:

Implementation of multiparametric magnetic resonance imaging technology for evaluation of patients with suspicion for prostate cancer in the clinical practice setting

Abstract

Objectives

To investigate the impact of implementing magnetic resonance imaging (MRI) and ultrasonography fusion technology on biopsy and prostate cancer (PCa) detection rates in men presenting with clinical suspicion for PCa in the clinical practice setting.

Patients and Methods

We performed a review of 1 808 consecutive men referred for elevated prostate‐specific antigen (PSA) level between 2011 and 2014. The study population was divided into two groups based on whether MRI was used as a risk stratification tool. Univariable and multivariable analyses of biopsy rates and overall and clinically significant PCa detection rates between groups were performed.

Results

The MRI and PSA‐only groups consisted of 1 020 and 788 patients, respectively. A total of 465 patients (45.6%) in the MRI group and 442 (56.1%) in the PSA‐only group underwent biopsy, corresponding to an 18.7% decrease in the proportion of patients receiving biopsy in the MRI group (P < 0.001). Overall PCa (56.8% vs 40.7%; P < 0.001) and clinically significant PCa detection (47.3% vs 31.0%; P < 0.001) was significantly higher in the MRI vs the PSA‐only group. In logistic regression analyses, the odds of overall PCa detection (odds ratio [OR] 1.74, 95% confidence interval [CI] 1.29–2.35; P < 0.001) and clinically significant PCa detection (OR 2.04, 95% CI 1.48–2.80; P < 0.001) were higher in the MRI than in the PSA‐only group after adjusting for clinically relevant PCa variables.

Conclusion

Among men presenting with clinical suspicion for PCa, addition of MRI increases detection of clinically significant cancers while reducing prostate biopsy rates when implemented in a clinical practice setting.

Read the full article

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Article of the month: Implementation of multiparametric MRI technology for evaluation of PCa in the clinic

Every month, the Editor-in-Chief selects an Article of the Month from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an editorial written by a prominent member of the urological community, and a podcast produced by our current Resident Podcasters. These are intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation. 

If you only have time to read one article this week, it should be this one.

Implementation of multiparametric magnetic resonance imaging technology for evaluation of patients with suspicion for prostate cancer in the clinical practice setting

Paras H. Shah*, Vinay R. Patel, Daniel M. Moreira, Arvin K. George§, Manaf Alom*, Zachary Kozel, Vidhu Joshi*, Eran Ben-Levi**, Robert Villani**, Oksana Yaskiv††Louis R. Kavoussi, Manish Vira, Carl O. Olsson‡‡ and Ardeshir R. Rastinehad

 

*Department of Urology, Mayo Clinic, Rochester, MN, Department of Urology, Icahn Smith Institute for Urology, Northwell Health, New York, NY, Department of Urology, University of Illinois at Chicago, Chicago, IL, §Department of Urology, University of Michigan, Ann Arbor, MI, Department of Urology, Smith Institute for Urology, Northwell Health, **Department of Radiology, Hofstra Northwell School of Medicine, ††Department of Pathology, Hofstra Northwell School of Medicine, New Hyde Park, and ‡‡Integrated Medical Professionals, Melville, NY, USA

 

Read the full article

Abstract

Objectives

To investigate the impact of implementing magnetic resonance imaging (MRI) and ultrasonography fusion technology on biopsy and prostate cancer (PCa) detection rates in men presenting with clinical suspicion for PCa in the clinical practice setting.

Patients and Methods

We performed a review of 1 808 consecutive men referred for elevated prostate‐specific antigen (PSA) level between 2011 and 2014. The study population was divided into two groups based on whether MRI was used as a risk stratification tool. Univariable and multivariable analyses of biopsy rates and overall and clinically significant PCa detection rates between groups were performed.

Results

The MRI and PSA‐only groups consisted of 1 020 and 788 patients, respectively. A total of 465 patients (45.6%) in the MRI group and 442 (56.1%) in the PSA‐only group underwent biopsy, corresponding to an 18.7% decrease in the proportion of patients receiving biopsy in the MRI group (P < 0.001). Overall PCa (56.8% vs 40.7%; P < 0.001) and clinically significant PCa detection (47.3% vs 31.0%; P < 0.001) was significantly higher in the MRI vs the PSA‐only group. In logistic regression analyses, the odds of overall PCa detection (odds ratio [OR] 1.74, 95% confidence interval [CI] 1.29–2.35; P < 0.001) and clinically significant PCa detection (OR 2.04, 95% CI 1.48–2.80; P < 0.001) were higher in the MRI than in the PSA‐only group after adjusting for clinically relevant PCa variables.

Conclusion

Among men presenting with clinical suspicion for PCa, addition of MRI increases detection of clinically significant cancers while reducing prostate biopsy rates when implemented in a clinical practice setting.

Read more Articles of the week

 

Article of the Week: Accuracy of ultrasonography for renal stone detection and size determination: is it good enough for management decisions?

Every week the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an accompanying editorial written by a prominent member of the urological community. This blog is intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.

Finally, the third post under the Article of the Week heading on the homepage will consist of additional material or media. This week we feature a video discussing the paper.

If you only have time to read one article this week, it should be this one.

Accuracy of ultrasonography for renal stone detection and size determination: is it good enough for management decisions?

Vishnu Ganesan*,, Shubha De*, Daniel Greene*, Fabio Cesar Miranda Torricelli* and Manoj Monga*

 

*Glickman Urological Kidney Institute, and Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, USA

 

Read the full article

Abstract

Objectives

To determine the sensitivity and specificity of ultrasonography (US) for detecting renal calculi and to assess the accuracy of US for determining the size of calculi and how this can affect counselling decisions.

Materials and Methods

We retrospectively identified all patients at our institution with a diagnosis of nephrolithiasis who underwent US followed by non-contrast computed tomography (CT) within 60 days. Data on patient characteristics, stone size (maximum axial diameter) and stone location were collected. The sensitivity, specificity and size accuracy of US was determined using CT as the standard.

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Results

A total of 552 US and CT examinations met the inclusion criteria. Overall, the sensitivity and specificity of US was 54 and 91%, respectively. There was a significant association between sensitivity of US and stone size (P < 0.001), but not with stone location (P = 0.58). US significantly overestimated the size of stones in the 0–10 mm range (P < 0.001). Assuming patients with stones 0–4 mm in size will be selected for observation and those with stones ≥5 mm could be counselled on the alternative of intervention, we found that in 14% (54/384) of cases where CT would suggest observation, US would lead to a recommendation for intervention. By contrast, when CT results would suggest intervention as management, US would suggest observation in 39% (65/168) of cases. An average of 22% (119/552) of patients could be inappropriately counselled. Stones classified as 5–10 mm according to US had the highest probability (43% [41/96]) of having their management recommendation changed when CT was performed. The use of plain abdominal film of kidney, ureter and bladder and US increases sensitivity (78%), but 37% (13/35) of patients may still be counselled inappropriately to undergo observation.

Conclusions

Using US to guide clinical decision-making for residual or asymptomatic calculi is limited by low sensitivity and inability to size the stone accurately. As a result, one in five patients may be inappropriately counselled when using US alone.

Read more articles of the week

Editorial: Ultrasonography vs computed tomography for stone size

In this edition of the BJUI Ganesan et al. [1] report a retrospective analysis of 552 ultrasonography (US) examinations that were followed by a non-contrast CT within 60 days in 486 patients collected over an 18-year period (1995–2012). The sensitivity of US for stone detection was 54% and its specificity was 91% when compared to CT, and sensitivity was positively associated with stone size (increasing from 73% for stones of 0–4 mm to 77% for 5–10 mm, and 89% for >10 mm; P < 0.001), but not with intra-renal location of stones (P = 0.58). US overestimated the size of stones that were <10 mm (P < 0.001), and had a tendency to underestimate size for those >10 mm (P = 0.05).

Stones were grouped into three size categories, based on clinical relevance to stone management: ≤4 mm (where observation would likely be recommended), 5–10 mm (where shockwave lithotripsy [SWL] would be chosen) or >10 mm where an endoscopic approach would be undertaken). Using these thresholds, 39% of cases would have been misassigned to observation and 14% of patients would have been inappropriately advised to undergo active treatment.

One may question the use of CT as the ‘gold standard’, as CT is also prone to sizing inaccuracy. Nevertheless, the headline findings that the inaccuracies inherent in US diagnosis and sizing may compromise clinical management are important. Other authors have made similar observations: in a literature review, Ray et al. [2] reported that US sensitivity was 45% for the detection of renal and ureteric calculi, with specificity up to 94% for ureteric stones and 88% for renal stones and that US overestimated stone size by a mean of 1.9 mm over CT, especially with stones of <5 mm. Similarly, Sternberg et al. [3] showed that the largest stone diameter was over-estimated by an average of 2.2 mm with US, and that errors increased with reducing stone size, rising from a 3% difference in stones >10 mm to 27% for those of 5–10 mm, and an 85% difference in stones ≤5 mm.

It is well established that, whilst having the advantage of no radiation dose, that US is a ‘user dependent’ study but there are also inherent limitations of US compared to CT for stone imaging. CT is capable of much finer spatial resolution, whilst US is prey to more diagnostic confounders. Reflectivity arising from sinus fat or the edges of the papillae may be mistaken for small calculi. For size, it can be difficult to delineate stone edges with the same precision as with CT. The sensitivity of US for stone detection can be improved by adjusting the imaging modalities between ray line (the conventional form of US), spatial compound and harmonic imaging (the most accurate stone size modality). Techniques such as increasing the gain and the transducer-to-stone depth and identifying ‘twinkle artefact’ using colour Doppler have also been used to improve stone detection [4].

However, manoeuvres to improve sensitivity of US may also compromise size measurement. An in vitro study has shown that each 2 cm increase in depth setting increases the size overestimation of stones by ~22% [5]. Using calcium oxalate monohydrate stones, the same group have shown that measuring the posterior acoustic shadow provided a more precise assessment of stone size than measurement of the stone itself [4]. Interestingly, the accuracy of stone width measurement was worse with greater transducer-to-stone depth, but measurement of the shadow width was independent of depth, and all US modalities (ray line, spatial compound, and harmonic imaging) performed similarly for shadow size. Shadow measurement was accurate to within 1 mm of the stone size [4], and similar findings have been shown in vivo, where 73% of the stone measurements and 85% of the shadow measurements were within 2 mm of the size on CT [6].

Unfortunately, not all stones cast an acoustic shadow, particularly the smaller ones, which are most likely to be over-sized. May et al. [6] showed that 89% of stones >5 mm, but only 53% of stones <5 mm demonstrated a posterior acoustic shadow. However, this may provide a further value for US-based clinical decision making, as stones that do not shadow are most likely <5 mm and are small enough to pass spontaneously, and therefore to be managed conservatively.

It is also important to be aware that CT stone measurements are also prone to error and inter-observer variability. Comparing in vitro CT measurements of stones in a ‘kidney sized potato model’, Eisner et al. [7] have shown that the most accurate measurements were obtained using magnified ‘bone window’ settings, which showed a mean 0.13 mm difference compared to a ‘gold standard’ measurement using callipers. This study also included a comparison of size estimate for spontaneously passed ureteric stones (thus a true reference standard) demonstrating that magnified ‘bone window’ measurements were equivalent to digital calliper measurements (the mean underestimation vs digital callipers was only 0.3 mm, P = 0.4), while measurements using magnified soft tissue windows were statistically different (mean underestimation 1.4 mm, P = 0.001) [7].

With its safety and accessibility, US should be the ideal modality for postoperative follow-up, both for assessment of stone recurrence, monitoring for enlargement of residual fragments, and for identifying the rare but important finding of ‘silent obstruction’, with the potential to lose renal function. However, given the ‘real-life’ data reported in this edition of the BJUI [1], and particularly the findings that 22% of patients might have been managed inappropriately when using US for decision making alone, increasing to 43% of patients who had stones between 5 and 10 mm on US, the authors have concluded that patients monitored by US might benefit from an additional CT if intervention is being considered, particularly for stones in the 5–10 mm range by US measurement.

Given the key importance of stone size to the outcome of interventions for stone disease, accurate imaging should translate into improved decision making and patient counselling and allow fairer inter-surgeon and departmental comparisons. Until the best US protocol and settings have been established, we recommend that, when US is used for diagnosis or follow-up, careful optimisation of the settings is crucial. Colour Doppler for ‘twinkle artefact’, and a high gain setting can be used to reduce the risk of missing stones, combined with removing all filtering and compressing the grey scale range to enhance the posterior shadowing. Harmonic imaging (which is now available on most commercial machines) is more accurate than cross beam or compound beams (that are used for standard renal US settings). When decisions need to be made, particularly those based on stone size, CT of the kidneys, ureters and bladder remains invaluable, from which the longest stone diameter should be measured, using magnified images and the ‘bone window’ setting. Current methods for accurate estimation of stone volume are impractical or imprecise. Manual segmentation can be accurate but is laborious, whilst standard semi-ellipsoid formulae cannot account for the wide variety of stone shapes seen in practice. Further studies devoted to simplifying stone volume estimation are necessary. There is also the wider challenge of how best to report stone imaging data. The key variables are stone size, density and location; and the morphology of the collecting system. Agreement between the various stakeholders – sonographers, radiologists and endourologists – over imaging standards and a minimal data set for stone imaging would improve management.

Daron Smith* and Uday Patel

 

*Institute of Urology, University College Hospital, and Department of Radiology, St Georges Hospital, London, UK

Read the full article

 

References

 

 

2 Ray AA, Ghiculete D, Pace KT, Honey RJ. Limitations to ultrasound in the detection and measurement of urinary tract calculi. Urology 2010; 76: 295300

 

3 Sternberg KM, Eisner B, Larson T, Hernandez N, Han J, Pais VMUltrasonography signicantly overestimates stone size when compared to low-dose, noncontrast computed tomography. Urology 2016; 95: 6771

 

4 Dunmire B, Harper JD, Cunitz BW et al. Use of the acoustic shadow width to determine kidney stone size with ultrasound. J Urol 2016; 195: 1717

 

5 Dunmire B, Lee FC, Hsi RS et al. Tools to improve the accuracy of kidney stone sizing with ultrasound. J Endourol 2015; 29: 14752

 

6 May PC, Haider Y, Dunmire B et al. Stone-mode ultrasound for determining renal stone size. J Endourol 2016; 30: 95862

 

 

Video: Accuracy of ultrasonography for renal stone detection and size determination: is it good enough for management decisions?

Accuracy of ultrasonography for renal stone detection and size determination: is it good enough for management decisions?

 

Read the full article

Abstract

Objectives

To determine the sensitivity and specificity of ultrasonography (US) for detecting renal calculi and to assess the accuracy of US for determining the size of calculi and how this can affect counselling decisions.

Materials and Methods

We retrospectively identified all patients at our institution with a diagnosis of nephrolithiasis who underwent US followed by non-contrast computed tomography (CT) within 60 days. Data on patient characteristics, stone size (maximum axial diameter) and stone location were collected. The sensitivity, specificity and size accuracy of US was determined using CT as the standard.

Results

A total of 552 US and CT examinations met the inclusion criteria. Overall, the sensitivity and specificity of US was 54 and 91%, respectively. There was a significant association between sensitivity of US and stone size (P < 0.001), but not with stone location (P = 0.58). US significantly overestimated the size of stones in the 0–10 mm range (P < 0.001). Assuming patients with stones 0–4 mm in size will be selected for observation and those with stones ≥5 mm could be counselled on the alternative of intervention, we found that in 14% (54/384) of cases where CT would suggest observation, US would lead to a recommendation for intervention. By contrast, when CT results would suggest intervention as management, US would suggest observation in 39% (65/168) of cases. An average of 22% (119/552) of patients could be inappropriately counselled. Stones classified as 5–10 mm according to US had the highest probability (43% [41/96]) of having their management recommendation changed when CT was performed. The use of plain abdominal film of kidney, ureter and bladder and US increases sensitivity (78%), but 37% (13/35) of patients may still be counselled inappropriately to undergo observation.

Conclusions

Using US to guide clinical decision-making for residual or asymptomatic calculi is limited by low sensitivity and inability to size the stone accurately. As a result, one in five patients may be inappropriately counselled when using US alone.

View more videos

Article of the Week: TRUS-Guided RB PCa Detection – Reasons for Targeted Biopsy Failure

Every Week the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.

In addition to the article itself, there is an accompanying editorial written by a prominent member of the urological community. This blog is intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.

Finally, the third post under the Article of the Week heading on the homepage will consist of additional material or media. This week we feature a video from Hannes Cash and Patrick Asbach, discussing their paper.

If you only have time to read one article this week, it should be this one.

Prostate cancer detection on transrectal ultrasonography-guided random biopsy despite negative real-time magnetic resonance imaging/ultrasonography fusion-guided targeted biopsy: reasons for targeted biopsy failure

Hannes Cash*, Karsten Gunzel*, Andreas Maxeiner*, Carsten Stephan*, Thomas Fischer, Tahir Durmus, Kurt Miller*, Patrick Asbach, Matthias Haas† and Carsten Kempkensteffen*

 

*Department of Urology, and Department of Radiology, ChariteUniversity of Medicine Berlin, Berlin, Germany M. H. and C.K. contributed equally to the study.

 

Read the full article

Objective

To examine the value of additional transrectal ultrasonography (TRUS)-guided random biopsy (RB) in patients with negative magnetic resonance imaging (MRI)/ultrasonography (US) fusion-guided targeted biopsy (TB) and to identify possible reasons for TB failure.

Patients and Methods

We conducted a subgroup analysis of 61 men with prostate cancer (PCa) detected by 10-core RB but with a negative TB, from a cohort of 408 men with suspicious multiparametric magnetic resonance imaging (mpMRI) between January 2012 and January 2015. A consensus re-reading of mpMRI results (using Prostate Imaging Reporting and Data System [PI-RADS] versions 1 and 2) for each suspicious lesion was performed, with the image reader blinded to the biopsy results, followed by an unblinded anatomical correlation of the lesion on mpMRI to the biopsy result. The potential reasons for TB failure were estimated for each lesion. We defined clinically significant PCa according to the Epstein criteria and stratified patients into risk groups according to the European Association of Urology guidelines.

JulAOTW3Results

Results

Our analysis showed that RB detected significant PCa in 64% of patients (39/61) and intermediate-/high-risk PCa in 57% of patients (35/61). The initial mpMRI reading identified 90 suspicious lesions in the cohort. Blinded consensus re-reading of the mpMRI led to PI-RADS score downgrading of 45 lesions (50%) and upgrading of 13 lesions (14%); thus, negative TB could be explained by falsely high initial PI-RADS scores for 32 lesions (34%) and sampling of the target lesion by RB in the corresponding anatomical site for 36 out of 90 lesions (40%) in 35 of 61 patients (57%). Sampling of the target lesion by RB was most likely for lesions with PI-RADS scores of 4/5 and Gleason scores (GS) of ≥7. A total of 70 PCa lesions (67% with GS 6) in 44 patients (72%) were sampled from prostatic sites with no abnormalities on mpMRI.

Conclusion

In cases of TB failure, RB still detected a high rate of significant PCa. The main reason for a negative TB was a TB error, compensated for by positive sampling of the target lesion by the additional RB, and the second reason for TB failure was a falsely high initial PI-RADS score. The challenges that arise for both MRI diagnostics and prostate lesion sampling are evident in our data and support the integration of RB into the TB workflow.

Read more articles of the week

Editorial: MRI-Fusion Biopsy – Behind the Scenes

MRI information of the prostate is increasingly used for improving the diagnostic yield of prostate biopsies [1]. However, increasing complexity of a procedure makes it prone to errors at multiple technical and human levels. Incorporating MRI information and ultrasonography (US) images for MRI-fusion biopsies is a technically challenging task. It involves various steps such as the acquisition and fusion of MRI and US images, the needle guidance during biopsy, and the diligence of the pathological evaluation of biopsy specimens. These different steps and interfaces between different medical professions influence the diagnostic performance of MRI-fusion biopsies.

For example, in daily clinical practice, MRIs from different institutions still harbour a great variance of sequences and reporting, despite the European Society of Urogenital Urology (ESUR) recently introducing acquisition and imaging protocols and a new and advanced version of the Prostate Imaging Reporting and Data System (PIRADS) version 2.0 [2]. The usefulness of such reporting schemes is evidenced by a moderate-to-good interobserver agreement between uro-radiologists for tumour lesion interpretation and corresponding κ values ranging from 0.55 to 0.80 [3]. Important pitfalls of image interpretation are benign lesions such as prostatitis, BPH and fibrosis, which might score similarly to prostate cancer lesions. This problem is further aggravated by a high proportion of patients that receive their first multiparametric MRI (mpMRI) of the prostate in the repeat-biopsy setting with a high burden of post-biopsy artefacts (haemorrhage, capsular irregularity) and lower overall cancer detection rate. Also, during MRI-fusion biopsy patient movement, prostate deformation by the US probe, and mismatch of image planes can lead to a biopsy error exceeding 4 mm. Moreover, targeting error might be aggravated by MRI underestimation of the tumour volume compared with final pathology [4]. After various authors reported the advantages and accuracy of MRI/US-fusion biopsy approaches, Cash et al. [5] address potential reasons for targeted biopsy failure to detect prostate cancer compared with random biopsy. Within their analyses the authors address potential limitations and technical considerations. Based on different technical biopsy strategies (with the patient placed within the MRI scanner (‘in-bore’) vs outside) and different technical approaches, these considerations are very important.

In contrast to cognitive fusion, most MRI/US platforms allow needle tracking by archiving the needle orientation, either by an electromagnetic, image-based or stepper-based mechanism [1]. However, lesion targeting by needle guidance is highly dependent on the dimensions of the primary lesion, numbers of relevant lesions, localisation, and overall prostate volume, making MRI-US fusion and cognitive fusion more error prone (i.e. aiming off the mark with the needle) than in-bore biopsies. Moreover, different technical fusion approaches provide different degrees of manual/automated adjustment tools, with for example either rigid or elastic image transformation to facilitate MRI/US image alignment.

In their analyses, Cash et al. [5] found that 34% of negative targeted biopsies could be explained by initially too high estimated PIRADS scores that were downgraded at re-reading. Interestingly, the remaining lesions were without an mpMRI correlate but within this group 92.9% showed a primary Gleason 3 pattern in biopsy pathology, suggesting a high degree of invisibility on mpMRI. Subanalyses did not show an association of targeted biopsy failures in the ventral location. Therefore, the study by Cash et al. [5] is an important precursor for further analyses to address other underlying reasons for targeted biopsy failure. Moreover, it reveals the need for a tight collaboration of radiologists, urologists, and pathologists as interdisciplinary partners involved in MRI-fusion biopsy. Consequently, the optimal diagnostic performance of MRI-fusion biopsies can only be achieved through standardised MRI performance, reading and reporting of MRI findings, as well as final correlation of MRI findings with histopathological work up.

Read the full article

Lars Budaus and Sami-Ramzi Leyh-Bannurah
Martini-Clinic University Hospital Hamburg-Eppendorf, Hamburg, Germany

 

References

 

 

Video: TRUS-Guided RB Prostate Cancer Detection – Reasons for Targeted Biopsy Failure

Prostate cancer detection on transrectal ultrasonography-guided random biopsy despite negative real-time magnetic resonance imaging/ultrasonography fusion-guided targeted biopsy: reasons for targeted biopsy failure

Hannes Cash*, Karsten Gunzel*, Andreas Maxeiner*, Carsten Stephan*, Thomas Fischer, Tahir Durmus, Kurt Miller*, Patrick Asbach, Matthias Haas† and Carsten Kempkensteffen*

 

*Department of Urology, and Department of Radiology, ChariteUniversity of Medicine Berlin, Berlin, Germany M. H. and C.K. contributed equally to the study.

 

Read the full article

Objective

To examine the value of additional transrectal ultrasonography (TRUS)-guided random biopsy (RB) in patients with negative magnetic resonance imaging (MRI)/ultrasonography (US) fusion-guided targeted biopsy (TB) and to identify possible reasons for TB failure.

Patients and Methods

We conducted a subgroup analysis of 61 men with prostate cancer (PCa) detected by 10-core RB but with a negative TB, from a cohort of 408 men with suspicious multiparametric magnetic resonance imaging (mpMRI) between January 2012 and January 2015. A consensus re-reading of mpMRI results (using Prostate Imaging Reporting and Data System [PI-RADS] versions 1 and 2) for each suspicious lesion was performed, with the image reader blinded to the biopsy results, followed by an unblinded anatomical correlation of the lesion on mpMRI to the biopsy result. The potential reasons for TB failure were estimated for each lesion. We defined clinically significant PCa according to the Epstein criteria and stratified patients into risk groups according to the European Association of Urology guidelines.

JulAOTW3Results

Results

Our analysis showed that RB detected significant PCa in 64% of patients (39/61) and intermediate-/high-risk PCa in 57% of patients (35/61). The initial mpMRI reading identified 90 suspicious lesions in the cohort. Blinded consensus re-reading of the mpMRI led to PI-RADS score downgrading of 45 lesions (50%) and upgrading of 13 lesions (14%); thus, negative TB could be explained by falsely high initial PI-RADS scores for 32 lesions (34%) and sampling of the target lesion by RB in the corresponding anatomical site for 36 out of 90 lesions (40%) in 35 of 61 patients (57%). Sampling of the target lesion by RB was most likely for lesions with PI-RADS scores of 4/5 and Gleason scores (GS) of ≥7. A total of 70 PCa lesions (67% with GS 6) in 44 patients (72%) were sampled from prostatic sites with no abnormalities on mpMRI.

Conclusion

In cases of TB failure, RB still detected a high rate of significant PCa. The main reason for a negative TB was a TB error, compensated for by positive sampling of the target lesion by the additional RB, and the second reason for TB failure was a falsely high initial PI-RADS score. The challenges that arise for both MRI diagnostics and prostate lesion sampling are evident in our data and support the integration of RB into the TB workflow.

Read more articles of the week

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