A multicentre assessment of prostate MRI quality and compliance with UK and international standards

AIM

To assess prostate magnetic resonance imaging (MRI) image quality and compliance with technical standards between centres in the South West region of the UK.

MATERIALS AND METHODS

Fifteen imaging sites in the region submitted seven consecutive anonymised MRI studies. These were assessed by two experienced radiologists in consensus. Overall, subjective image quality for T2-weighted imaging (T2W), diffusion weighted imaging (DWI), and dynamic contrast enhancement (DCE) was scored on a five-point Likert scale. Five additional quality parameters were also assessed visually, including image noise, motion, artefact, and distortion. The degree of compliance by each site with 21 published technical standards was also assessed.

RESULTS

Ninety-four MRI examinations were reviewed from across all sites (mean 6.3 scans per site, range 5-7). Mean compliance with technical standards was 63% (range 38-86%). Forty-seven percent of sites did not perform DCE. One site used a 3 T scanner. The percentage of patients with overall quality scores of ≥3 (diagnostically acceptable) were 68% for T2W, 81% for DWI, and 60% for both T2W and DWI. Ninety-three percent of the 45 patients who underwent DCE had diagnostically acceptable studies. By scanner age, the percentage of patients with diagnostically acceptable T2W scores was 53% for scanners ≥7 years and 80% when <7 years (p=0.006). Comparing individual sites, the mean overall quality scores were 2.9 (range 2.2-4.2) for T2W, 3.2 (1.8-4.7) for DWI, and 3.4 (2.5-4.7) for DCE.

CONCLUSION

There is wide variation in compliance with recognised technical standards and image quality across sites. If MRI is to replace biopsy in selected low-risk patients, improvements in image quality may be required.

PI-RADS version 2.1: one small step for prostate MRI

Multiparametric (mp) prostate magnetic resonance imaging (MRI) is playing an increasingly prominent role in the diagnostic work-up of patients with suspected prostate cancer. Performing mpMRI before biopsy offers several advantages including biopsy avoidance under certain clinical circumstances and targeting biopsy of suspicious lesions to enable the correct diagnosis. The success of the technique is heavily dependent on high-quality image acquisition, interpretation, and report communication, all areas addressed by previous versions of the Prostate Imaging-Reporting and Data System (PI-RADS) recommendations. Numerous studies have validated the approach, but the widespread adoption of PI-RADS version 2 has also highlighted inconsistencies and limitations, particularly relating to interobserver variability for evaluation of the transition zone. These limitations are addressed in the recently released version 2.1. In this article, we highlight the key changes proposed in PI-RADS v2.1 and explore the background reasoning and evidence for the recommendations.

3D-printed components for quantum devices

Recent advances in the preparation, control and measurement of atomic gases have led to new insights into the quantum world and unprecedented metrological sensitivities, e.g. in measuring gravitational forces and magnetic fields. The full potential of applying such capabilities to areas as diverse as biomedical imaging, non-invasive underground mapping, and GPS-free navigation can only be realised with the scalable production of efficient, robust and portable devices. We introduce additive manufacturing as a production technique of quantum device components with unrivalled design freedom and rapid prototyping. This provides a step change in efficiency, compactness and facilitates systems integration. As a demonstrator we present an ultrahigh vacuum compatible ultracold atom source dissipating less than ten milliwatts of electrical power during field generation to produce large samples of cold rubidium gases. This disruptive technology opens the door to drastically improved integrated structures, which will further reduce size and assembly complexity in scalable series manufacture of bespoke portable quantum devices.

Effect of hyoscine butylbromide on prostate multiparametric MRI anatomical and functional image quality

AIM

To evaluate the effect of the spasmolytic agent hyoscine butylbromide (HBB) on the quality of anatomical and functional imaging of the prostate.

MATERIALS AND METHODS

One hundred and seventy-three patients were included in this retrospective study. Eighty-seven patients received intravenous HBB prior to scanning (HBB group) and 86 patients did not (non-HBB group). Multiparametric (mp) 3 T magnetic resonance imaging (MRI) was performed using a 32-channel body coil. Two radiologists independently evaluated the image quality of T2-weighted imaging (WI), diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps, using a five-point Likert scale. DWI was further assessed for distortion and artefact (four-point Likert scale), and T2WI for the presence of motion artefact or blurring. Dynamic contrast-enhanced (DCE) image quality was assessed by recording the number of corrupt contrast curve data points.

RESULTS

T2W image quality in the HBB group was significantly higher than in the non-HBB group (3.63±1.11 versus 2.84±0.899); p<0.001. The HBB group also showed significantly less T2W motion and T2W blur than the non-HBB group (23% and 51.7% versus 53.5% and 83.7%, respectively; p<0.001); however, there was no significant improvement in DWI or ADC image quality, or DWI degree of distortion or artefact. There was a trend towards a lower number of corrupted data points from the contrast curve (2.47±2.44 versus 3.68±2.64), but this did not reach significance (p=0.052).

CONCLUSION

Administration of HBB significantly improves the image quality of T2WI images. These results provide evidence for the use of HBB in routine patient preparation prior to prostate mpMRI.

Sub-differentiating equivocal PI-RADS-3 lesions in multiparametric magnetic resonance imaging of the prostate to improve cancer detection

PURPOSE

To evaluate sub-differentiation of PI-RADS-3 prostate lesions using pre-defined T2- and diffusion-weighted (DWI) MRI criteria, to aid the biopsy decision process.

METHODS

143 patients with PIRADS-3 index lesions on MRI underwent targeted transperineal-MR/US fusion biopsy. Radiologists with 2 and 7-years experience performed blinded retrospective second-reads using set criteria and assigned biopsy recommendations. Inter-reader agreement, Gleason score (GS), positive (PPV) predictive values (±95% confidence intervals) were calculated and compared by Fisher's exact test with Bonferroni-Hom correction.

RESULTS

43% (61/143) patients had GS 6-10 and 21% (30/143) GS≥3+4 cancer. For peripheral zone lesions, significant differences in any cancer detection were found for shape (0.26±0.13 geographical vs. 0.69±0.23 rounded; p=0.0055) and ADC (mild 0.21±0.12 vs marked 0.81±0.19; p=0.0001). For transition zone, significantly increased cancer detection was shown for location (anterior 0.63±0.15 vs. mid/posterior 0.31±0.14; p=0.0048), border (pseudo-capsule 0.32±0.14 vs. ill-defined 0.61±0.15; p=0.0092), and ADC (mild 0.35±0.12 vs marked restriction 0.68±0.17; p=0.0057). Biopsy recommendations had 62% inter-reader agreement (89/143). Experienced reader PPVs were significantly higher for any cancer with "biopsy-recommended" 0.61±0.11 vs. "no biopsy" 0.21±0.10 (p=0.0001), and for GS 7-10 cancers: 0.32±0.10 vs. 0.08±0.07, respectively (p=0.0003).

CONCLUSION

Identification of certain objective imaging criteria as well as a subjective biopsy recommendation from an experienced radiologist can help to increase the predictive value of equivocal prostate lesions and inform the decision making process of whether or not to biopsy.

Novel three-dimensional bone 'mapping' software can help assess progression of osseous metastases from routine CT

Imaging of bone metastasis response to therapy is a research priority. Stradwin is a new software-tool, with demonstrated sub-voxel accuracy in assessing cortical bone properties from routine CT. We applied this technology to the context of osseous metastases, with particular focus on disease progression using prostate cancer as a model. 3D-rendered 'bone-maps' were produced for 20 men with advanced prostate cancer, including a sub-cohort of 9 who had undergone serial scans. Correlation between baseline interpretation and assessments of progression between modalities was assessed. Bone-maps took significantly less time to interpret than CT bone windows (P < 0.001). Initial bone-mapping, without adjustment, demonstrated sensitivity and specificity for suspicious areas on CT of 70.7% and 73.1% respectively. Evaluating disease over time, concordance between bone-maps and current practice using RECIST outcomes was 100%.This study demonstrates the feasibility and potential use of this free post-processing software in the serial assessment of osseous metastases.

The Uptake of Human Papillomavirus Vaccine In Irish Schools: The Impact Of Disadvantage

HPV vaccine Gardasil© is offered to girls in first year of secondary school in Ireland. We aimed to determine the association between HPV vaccine uptake among girls for academic year 2013/2014, by school and school characteristics: socioeconomic disadvantage and religious ethos. The National Schools Immunisation System (SIS) was searched to determine HPV vaccine uptake in schools for 2013/2014 (prior to recent anti-HPV vaccine publicity). The disadvantaged status and ethos of each school was added to the report. In total 577 schools were identified. Mean vaccine uptake was 83.7%. Disadvantaged schools had a lower mean uptake (%) than other schools (79.4% vs 85.0%, difference 5.58%, 95%CI 2.69-8.21) and were twice as likely to have an uptake of ?50% (OR 2.07, 95% CI 2.76 - 5.18). No difference was found between schools of different ethoses. HPV vaccine uptake is lower in disadvantaged Irish schools. Policies should be developed to ensure a more equitable uptake of HPV vaccine.

Prostate Cancer Metastatic to the Renal Allograft: A Case Report

Malignancy is a leading cause of morbidity and mortality in organ transplant recipients who receive immunosuppression. Cancers associated with viruses such as nonmelanotic skin cancer and Kaposi sarcoma occur in allograft recipients at rates that far exceed that in the general population. The increased risk and tumor type may depend not only on degree of immune system modulation but also on the type of organ transplanted. In kidney transplant recipients, the risk of cancers such as prostate and breast does not seem to be increased. However, these cancers tend to be advanced and aggressive. The management of these cancers is similar to the general population with the additional consideration for reduction in immunosuppression and conversion to sirolimus. Given the increased survival of both transplanted organs as well as organ recipients along with the increased number of older recipients, the diagnosis of prostate cancer in the older male organ recipient is increasing. The long-term outcomes using current treatment guidelines for prostate cancer in these individuals are not clear. We report a case of known localized prostate cancer in a renal transplant recipient presenting with metastasis diagnosed as tumor infiltration of the allograft. Our patient, upon initial diagnosis of cancer, opted for radiation with eventual androgen-deprivation therapy. This unusual site of prostate cancer spread heightens the need for awareness among providers as well as the need for further studies of the outcomes in these patients undergoing treatments designed using guidelines developed for those with normally functioning immunity.

Lesion Targeted CT-Guided Transgluteal Prostate Biopsy in Combination With Prebiopsy MRI in Patients Without Rectal Access

With prostate and colorectal malignancies being the most common cancers in men, elevated prostate specific antigen (PSA) in patients without rectal access due to prior surgery poses a diagnostic dilemma. We report the first use of CT-guided biopsy in combination with prebiopsy MRI in 2 patients with a clinical suspicion of prostate cancer and no rectal access. In both cases, a diagnostic multiparametric MRI of the prostate was performed to detect and to localize a potential suspicious lesion. The localization served as a cognitive map for guiding needle placement using a CT-guided transgluteal approach.

The Prostate Health Index adds predictive value to multi-parametric MRI in detecting significant prostate cancers in a repeat biopsy population

Both multi-parametric MRI (mpMRI) and the Prostate Health Index (PHI) have shown promise in predicting a positive biopsy in men with suspected prostate cancer. Here we investigated the value of combining both tests in men requiring a repeat biopsy. PHI scores were measured in men undergoing re-biopsy with an mpMRI image-guided transperineal approach (n = 279, 94 with negative mpMRIs). The PHI was assessed for ability to add value to mpMRI in predicting all or only significant cancers (Gleason ≥7). In this study adding PHI to mpMRI improved overall and significant cancer prediction (AUC 0.71 and 0.75) compared to mpMRI + PSA alone (AUC 0.64 and 0.69 respectively). At a threshold of ≥35, PHI + mpMRI demonstrated a NPV of 0.97 for excluding significant tumours. In mpMRI negative men, the PHI again improved prediction of significant cancers; AUC 0.76 vs 0.63 (mpMRI + PSA). Using a PHI≥35, only 1/21 significant cancers was missed and 31/73 (42%) men potentially spared a re-biopsy (NPV of 0.97, sensitivity 0.95). Decision curve analysis demonstrated clinically relevant utility of the PHI across threshold probabilities of 5-30%. In summary, the PHI adds predictive performance to image-guided detection of clinically significant cancers and has particular value in determining re-biopsy need in men with a negative mpMRI.

The 2000 Canine Distemper Epidemic in Caspian Seals (Phoca caspica): Pathology and Analysis of Contributory Factors

More than 10,000 Caspian seals ( Phoca caspica) were reported dead in the Caspian Sea during spring and summer 2000. We performed necropsies and extensive laboratory analyses on 18 seals, as well as examination of the pattern of strandings and variation in weather in recent years, to identify the cause of mortality and potential contributory factors. The monthly stranding rate in 2000 was up to 2.8 times the historic mean. It was preceded by an unusually mild winter, as observed before in mass mortality events of pinnipeds. The primary diagnosis in 11 of 13 seals was canine distemper, characterized by broncho-interstitial pneumonia, lymphocytic necrosis and depletion in lymphoid organs, and the presence of typical intracytoplasmic inclusion bodies in multiple epithelia. Canine distemper virus infection was confirmed by phylogenetic analysis of reverse transcriptase-polymerase chain reaction products. Organochlorine and zinc concentrations in tissues of seals with canine distemper were comparable to those of Caspian seals in previous years. Concurrent bacterial infections that may have contributed to the mortality of the seals included Bordetella bronchiseptica (4/8 seals), Streptococcus phocae (3/8), Salmonella dublin (1/8), and S. choleraesuis (1/8). A newly identified bacterium, Corynebacterium caspium, was associated with balanoposthitis in one seal. Several infectious and parasitic organisms, including poxvirus, Atopobacter phocae, Eimeria- and Sarcocystis-like organisms, and Halarachne sp. were identified in Caspian seals for the first time.