Marcin Czarniecki

Ultra-small superparamagnetic iron oxide contrast agents for lymph node staging of high-risk prostate cancer

Ultrasmall superparamagnetic particles of iron oxide (USPIOs) imaged with magnetic resonance imaging (MRI) have been proposed as an experimental method for visualizing lymph node (LN) metastases. The method does not require ionizing radiation, yet can detect small nodes that are involved with metastases. USPIOs are naturally taken up by macrophages that deposit in the normal LN creating a low signal region in normal areas; areas within the node that do not show this loss of signal are likely involved by tumor although there can be other causes (fibrosis or inflammation). However, the lack of approved USPIOs that are clinically available hinders adoption and larger studies. The proposed indications for USPIO MRI, including specific compounds and imaging methods are discussed.

Imaging findings of hereditary renal tumors, a review of what the radiologist should know

It is estimated that up to 8% of currently diagnosed renal cancers are part of a hereditary syndrome. The radiologist may be the first person to associate a renal tumor presenting during an imaging study to other manifestations of a hereditary syndrome. This diagnosis can have broad implications for the patient but also for other family members. This update reviews the current known associations and emerging mutations of hereditary renal cancers from a radiologists perspective. Renal manifestations, as well as associated radiological findings and pitfalls are discussed. Additionally, screening and surveillance recommendations are also discussed to aid radiologists in the decision-making process for patient management.

Evaluation of lymph node status in patients with urothelial carcinoma—still in search of the perfect imaging modality: a systematic review

While accurate lymph node status evaluation in urothelial carcinoma patients is essential for the correct disease staging and, hence, establishing the most beneficial treatment strategy, the diagnostic performance of routine imaging in regards to this issue is not satisfactory. For the purpose of this article, we systematically reviewed the contemporary literature on the sensitivity and specificity of particular imaging modalities which have been studied for detecting lymph node metastases in patients diagnosed with urothelial carcinoma. The evidence reviewed shows that computed tomography (CT), although recognized as the imaging modality of choice, is associated with marked limitations, resulting in its low sensitivity for lymph node involvement detection in urothelial carcinoma patients, with no study reporting a value higher than 46% using standard cut-off values. Markedly higher sensitivity rates may be achieved with magnetic resonance imaging (MRI), especially when using ultrasmall superparamagnetic iron oxide as the contrast agent, however, no uniform protocol has been systematically studied up to date. The vast majority of recent evidence concerns positron emission tomography (PET), which is being reported to improve the diagnostic performance of CT alone, as has been demonstrated in multiple articles, which investigated the accuracy of PET/CT at primary or post-treatment staging of urothelial carcinoma patients. However, there has been substantial heterogeneity in terms of methodology and results between those studies, making it premature to draw any definitive conclusions. The results of this review lead to a conclusion, that while CT, despite being not fully satisfactory, still remains the gold-standard method of imaging for staging purposes in urothelial carcinoma, other imaging modalities are under investigation, with promising results.

Keeping up with the prostate-specific membrane antigens (PSMAs): an introduction to a new class of positron emission tomography (PET) imaging agents

Prostate-specific membrane antigen (PSMA) targeted positron emission tomography (PET) is an emerging prostate cancer imaging method, which has been reported to have a higher sensitivity and specificity than the currently approved PET imaging agents. Multiple PSMA ligands are being investigated around the world and applications range from primary tumor characterization, to local staging, biochemical recurrence, metastasis, and image-guided interventions. The most investigated PET tracers are labelled with 68-Gallium or 18-Fluoride and are discussed in this review. Additionally, 99mTc labeled PSMA agents for single photon emission computed tomography (SPECT) imaging are elucidated as an alternative method of PSMA image acquisition.

Predicting Gleason Group Progression for Men on Prostate Cancer Active Surveillance: The Role of a Negative Confirmatory MRI-US Fusion Biopsy

Purpose: Active surveillance has gained acceptance as an alternative to definitive therapy in many men with prostate cancer. Confirmatory biopsies to assess the appropriateness of active surveillance are routinely performed and negative biopsies are regarded as a favorable prognostic indicator. We sought to determine the prognostic implications of negative multiparametric magnetic resonance imaging-transrectal ultrasound guided fusion biopsy consisting of extended sextant, systematic biopsy plus multiparametric magnetic resonance imaging guided targeted biopsy of suspicious lesions on magnetic resonance imaging. Materials and Methods: All patients referred with Gleason Grade Group 1 or 2 prostate cancer based on systematic biopsy performed elsewhere underwent confirmatory fusion biopsy. Patients who continued on active surveillance after a positive or a negative fusion biopsy were followed. The baseline characteristics of the biopsy negative and positive cases were compared. Cox regression analysis was used to determine the prognostic significance of a negative fusion biopsy. Kaplan-Meier survival curves were used to estimate Grade Group progression with time. Results: Of the 542 patients referred with Grade Group 1 (466) or Grade Group 2 (76) cancer 111 (20.5%) had a negative fusion biopsy. A total of 60 vs 122 patients with a negative vs a positive fusion biopsy were followed on active surveillance with a median time to Grade Group progression of 74.3 and 44.6 months, respectively (p <0.01). Negative fusion biopsy was associated with a reduced risk of Grade Group progression (HR 0.41, 95% CI 0.22-0.77, p <0.01). Conclusions: A negative confirmatory fusion biopsy confers a favorable prognosis for Grade Group progression. These results can be used when counseling patients about the risk of progression and for planning future followup and biopsies in patients on active surveillance.PURPOSEnActive surveillance has gained acceptance as an alternative to definitive therapy in many men with prostate cancer. Confirmatory biopsies to assess the appropriateness of active surveillance are routinely performed and negative biopsies are regarded as a favorable prognostic indicator. We sought to determine the prognostic implications of negative multiparametric magnetic resonance imaging-transrectal ultrasound guided fusion biopsy consisting of extended sextant, systematic biopsy plus multiparametric magnetic resonance imaging guided targeted biopsy of suspicious lesions on magnetic resonance imaging.nnnMATERIALS AND METHODSnAll patients referred with Gleason Grade Group 1 or 2 prostate cancer based on systematic biopsy performed elsewhere underwent confirmatory fusion biopsy. Patients who continued on active surveillance after a positive or a negative fusion biopsy were followed. The baseline characteristics of the biopsy negative and positive cases were compared. Cox regression analysis was used to determine the prognostic significance of a negative fusion biopsy. Kaplan-Meier survival curves were used to estimate Grade Group progression with time.nnnRESULTSnOf the 542 patients referred with Grade Group 1 (466) or Grade Group 2 (76) cancer 111 (20.5%) had a negative fusion biopsy. A total of 60 vs 122 patients with a negative vs a positive fusion biopsy were followed on active surveillance with a median time to Grade Group progression of 74.3 and 44.6 months, respectively (p <0.01). Negative fusion biopsy was associated with a reduced risk of Grade Group progression (HR 0.41, 95% CI 0.22-0.77, p <0.01).nnnCONCLUSIONSnA negative confirmatory fusion biopsy confers a favorable prognosis for Grade Group progression. These results can be used when counseling patients about the risk of progression and for planning future followup and biopsies in patients on active surveillance.

Added Value of Multiparametric Magnetic Resonance Imaging to Clinical Nomograms for Predicting Adverse Pathology in Prostate Cancer

Purpose We examined the additional value of preoperative prostate multiparametric magnetic resonance imaging and transrectal ultrasound/multiparametric magnetic resonance imaging fusion guided targeted biopsy when performed in combination with clinical nomograms to predict adverse pathology at radical prostatectomy. Materials and Methods We identified all patients who underwent 3 Tesla multiparametric magnetic resonance imaging prior to fusion biopsy and radical prostatectomy. The Partin and the MSKCC (Memorial Sloan Kettering Cancer Center) preradical prostatectomy nomograms were applied to estimate the probability of organ confined disease, extraprostatic extension, seminal vesicle invasion and lymph node involvement using transrectal ultrasound guided systematic biopsy and transrectal ultrasound/multiparametric magnetic resonance imaging fusion guided targeted biopsy Gleason scores. With radical prostatectomy pathology as the gold standard we developed multivariable logistic regression models based on these nomograms before and after adding multiparametric magnetic resonance imaging to assess any additional predictive ability. Results A total of 532 patients were included in study. When multiparametric magnetic resonance imaging findings were added to the systematic biopsy based MSKCC nomogram, the AUC increased by 0.10 for organ confined disease (p <0.001), 0.10 for extraprostatic extension (p = 0.003), 0.09 for seminal vesicle invasion (p = 0.011) and 0.06 for lymph node involvement (p = 0.120). Using Gleason scores derived from targeted biopsy compared to systematic biopsy provided an additional predictive value of organ confined disease (&Dgr; AUC 0.07, p = 0.003) and extraprostatic extension (&Dgr; AUC 0.07, p = 0.048) at radical prostatectomy with the MSKCC nomogram. Similar results were obtained using the Partin nomogram. Conclusions Magnetic resonance imaging alone or in addition to standard clinical nomograms provides significant additional predictive ability of adverse pathology at the time of radical prostatectomy. This information can be greatly beneficial to urologists for preoperative planning and for counseling patients regarding the risks of future therapy.

Comparison of Elastic and Rigid Registration during Magnetic Resonance Imaging/Ultrasound Fusion-Guided Prostate Biopsy: A Multi-Operator Phantom Study

Purpose The relative value of rigid or elastic registration during magnetic resonance imaging/ultrasound fusion guided prostate biopsy has been poorly studied. We compared registration errors (the distance between a region of interest and fiducial markers) between rigid and elastic registration during fusion guided prostate biopsy using a prostate phantom model. Materials and Methods Four gold fiducial markers visible on magnetic resonance imaging and ultrasound were placed throughout 1 phantom prostate model. The phantom underwent magnetic resonance imaging and the fiducial markers were labeled as regions of interest. An experienced user and a novice user of fusion guided prostate biopsy targeted regions of interest and then the corresponding fiducial markers on ultrasound after rigid and then elastic registration. Registration errors were compared. Results A total of 224 registration error measurements were recorded. Overall elastic registration did not provide significantly improved registration error over rigid registration (mean ± SD 4.87 ± 3.50 vs 4.11 ± 2.09 mm, p = 0.05). However, lesions near the edge of the phantom showed increased registration errors when using elastic registration (5.70 ± 3.43 vs 3.23 ± 1.68 mm, p = 0.03). Compared to the novice user the experienced user reported decreased registration error with rigid registration (3.25 ± 1.49 vs 4.98 ± 2.10 mm, p <0.01) and elastic registration (3.94 ± 2.61 vs 6.07 ± 4.16 mm, p <0.01). Conclusions We found no difference in registration errors between rigid and elastic registration overall but rigid registration decreased the registration error of targets near the prostate edge. Additionally, operator experience reduced registration errors regardless of the registration method. Therefore, elastic registration algorithms cannot serve as a replacement for attention to detail during the registration process and anatomical landmarks indicating accurate registration when beginning the procedure and before targeting each region of interest.

Imaging of distant metastases of prostate cancer

The detection of distant metastases at the initial diagnosis of prostate cancer (PCa) establishes the treatment approach and has a prognostic value, nevertheless it is not well established. Since proposed staging approaches often contradict each other, we aimed to compare the current imaging techniques for staging of advanced PCa, including future applications of the most innovative methods. Conventional imaging techniques, including computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) have been employed for metastatic staging (both N and M staging) of men with high-risk PCa, but surgical pelvic dissection remains the gold standard for N staging. However, functional MRI by using diffusion-weighted imaging, MR lymphography (MRL) with ultra-small paramagnetic iron oxide particles (USPIO), and hybrid PET/MRI imaging showed both high sensitivity and high specificity for nodal staging and depicting metastases. The standard of practice for M staging in PCa includes the radionuclide bone scan and targeted X-ray film, but their performance has generally been poor. Recently, MRI showed promising results with applications in both local and distant staging. Finally, with the development of new PET tracers, PET/CT and PET/MRI offer a combination of excellent pharmacokinetic characteristics, functional information, and precise anatomic localization and morphological correlation of tumor lesions.

Incidental bladder cancers found on multiparametric MRI of the prostate gland: a single center experience

PURPOSEnIn the era of multiparametric magnetic resonance imaging (mpMRI) of the prostate gland, incidental findings are occasionally discovered on imaging. We aimed to report our experience of detecting incidental bladder cancers on mpMRI of the prostate in asymptomatic patients without irritative voiding symptoms or microscopic or gross hematuria.nnnMETHODSnA retrospective review was performed on a prospectively maintained database of all men who underwent prostate mpMRI at our institution from 2012 to 2018. Patients who were found to have incidental bladder lesions were identified and baseline demographics, imaging and histopathologic data were recorded. All patients with incidental bladder lesion detection on mpMRI, not attributable to extension of prostate cancer, underwent cystoscopy in addition to a biopsy and/or transurethral resection of bladder tumor (TURBT) if warranted on cystoscopy.nnnRESULTSnThere were 3147 prostate mpMRIs performed during this period and 25 cases (0.8%) of incidental bladder lesions were detected. These patients did not have any presenting symptoms such as gross or microscopic hematuria to prompt bladder lesion workup. The largest diameter of incidentally discovered bladder lesions ranged from 0.4 cm to 1.7 cm. Of the 25 cases of incidental bladder lesions, five were suspected to be due to prostate cancer invasion into the bladder. Only two of these five patients underwent biopsy, which confirmed prostate adenocarcinoma in both cases. Of the 20 patients without suspected prostate cancer invasion of the bladder, four had no suspicious lesions on cystoscopy to warrant a biopsy. The remaining 16 patients had bladder lesions seen on cystoscopy and underwent a biopsy and/or TURBT. Three of these patients had benign features on pathology (urachal remnant, amyloidosis and inflammation) and the remaining 13 had stage Ta urothelial carcinoma. Seven of these patients had low-grade Ta tumors and six had high-grade Ta tumors. All patients were treated with standard management of TURBT with or without intravesical BCG. There have been no reported cases of recurrence or progression in any of the patients in our cohort at the median follow-up of 26 months (interquartile range,19-40 months).nnnCONCLUSIONnmpMRI of the prostate may yield incidental findings, such as small bladder tumors. Awareness of the possibility of incidental bladder lesions is important as 65% of lesions reported in the bladder, not attributable to extension of prostate cancer, proved to be bladder cancer. This may allow for early intervention for asymptomatic patients with undetected bladder cancer prior to disease progression.

Radiomics and radiogenomics of prostate cancer

Radiomics and radiogenomics are attractive research topics in prostate cancer. Radiomics mainly focuses on extraction of quantitative information from medical imaging, whereas radiogenomics aims to correlate these imaging features to genomic data. The purpose of this review is to provide a brief overview summarizing recent progress in the application of radiomics-based approaches in prostate cancer and to discuss the potential role of radiogenomics in prostate cancer.