MRI fusion biopsy systems for diagnosing prostate cancer

The NICE guideline on prostate cancer recommends that a multiparametric MRI test should be offered to people with suspected clinically localised prostate cancer. People with a significant lesion should be offered a multiparametric MRI-influenced prostate biopsy. Based on prostate-specific antigen test results, Gleason score determined by histological analysis of the biopsy, and clinical stage based on the multiparametric MRI scan, people are assigned to risk categories. This informs treatment options (such as active surveillance, radical prostatectomy and radiotherapy).

Targeted biopsies, which take only a small number of tissue samples or cores, are done for suspicious lesions identified by MRI. A systematic biopsy approach, in which multiple samples are taken from different regions of the left and right side of the prostate, can be done alongside a targeted biopsy. This can be done if radiologists are unsure if the lesion is malignant and clinical suspicion of cancer is high. Clinical experts explained that the biopsy approach depends on the information from the multiparametric MRI and individual clinician preference. They commented that practice in the NHS varies.

Targeted biopsies are usually done using cognitive fusion, in which the previously captured MRI image is visually compared with the live transrectal ultrasound image to guide the biopsy needle. Because of the differences in positioning when a person has an MRI scan compared with when they have an ultrasound scan, the prostate shape differs on MRI and ultrasound images. This can make targeting the lesion difficult.

In MRI fusion biopsy systems, the MRI image is fused onto the live ultrasound image to aid biopsy targeting. MRI fusion biopsy systems are indicated for targeted biopsies of suspicious lesions when a small number of tissue samples or cores are taken. The clinical experts commented that, as with cognitive fusion biopsies, systematic biopsies may be done alongside targeted biopsies done using MRI fusion.

The more samples taken during a prostate biopsy, the higher the risk of adverse events. Refined targeting of the prostate for biopsy could avoid taking unnecessary samples. This could reduce the risk of adverse events such as urinary retention, infection and sepsis after the biopsy. More accurate targeting of suspicious prostate lesions could increase prostate cancer detection rates (missing fewer cases), particularly for people with small lesions. It could also reduce the number of repeat biopsies needed by reducing the risk of missing the cancer in the first biopsy.

The Artemis fusion biopsy system (InnoMedicus Artemis) includes a semi-robotic mechanical arm and a mobile workstation. The system uses ProFuse radiology software for preparing MRI data for fusion and for reporting findings. The system uses both elastic and rigid estimation to account for changes in the shape of the prostate during the procedure, and supports transrectal and transperineal biopsies. The mechanical arm is used to track the prostate in real time and guide the biopsy needle.

It is unclear if the system is compatible with third-party ultrasound systems or picture archiving and communication systems (PACS), what its image measurement capabilities are or if it can produce archivable cartograms. No information on costings or regulatory approval has been received from the company.

The Biojet MR Fusion system (Healthcare Supply Solutions) comprises MRI fusion software, a mobile workstation, and is compatible with third-party ultrasound systems. The system uses elastic estimations to account for changes in the shape of the prostate during the procedure, and supports transrectal and transperineal biopsies. It supports stabilised and freehand biopsy approaches. For stabilised biopsies, patient movement is tracked through the stepper; freehand biopsies done without the stepper need more manual input from the user.

The software enables image measurements and a report is generated, graphically showing the sampled areas with exact locations. Biojet can be connected to a local PACS. No information on costings or regulatory approval has been received from the company.

The BiopSee system (Medcom) consists of BiopSee software and a MedSta cart (workstation) and is compatible with third-party ultrasound systems. The system uses elastic and rigid estimation to account for changes in the shape of the prostate during the procedure, and supports transrectal and transperineal biopsies. It can be used for stabilised and freehand biopsy approaches. A stabilising arm is available for transperineal stabilised biopsies. Patient movement is tracked through the stepper during stabilised biopsies, or through a magnetic tracker attached to the probe during freehand biopsies. The system can automatically adjust for patient movement, or the user can manually adjust the contours when a patient moves.

The BiopSee records all positions of the needle and shows the coverage of the prostate. Image measurements such as prostate and lesion volumes are also possible. The data is stored locally and can be connected to a PACS for import and export of images. The software costs £20,000 for transperineal biopsies and £15,000 for transrectal biopsies. The cart for transrectal biopsies costs £12,000, and the cart for transperineal biopsy costs £8,000 for stabilised biopsy and £20,000 for freehand biopsy.

BK Medical UK Ltd and MIM Software Inc offer 3 versions of bkFusion software: 1 for transrectal, 1 for freehand transperineal and 1 for stabilised transperineal biopsies. The software can be integrated into either the bk3000 or bk5000 ultrasound systems. The bkFusion system uses rigid estimation to account for changes in the shape of the prostate during the procedure. The stabilised transperineal fusion system uses a stepper to track the probe position.

Image measurements such as prostate volume are possible. A report of the biopsy can be saved locally, or transferred to a PACS. The software and cart cost £52,250 (provided for transperineal biopsy only).

FusionVu is a software feature that enables MRI fusion biopsy as part of the ExactVu micro-ultrasound system (ExactImaging). A stabiliser arm or stepper is available for stabilised biopsies, and freehand biopsies are also possible. The system uses rigid estimation followed by real-time visualisation of the lesions using micro-ultrasound. It supports transperineal and transrectal biopsies. The system tracks and adjusts for patient movement using data from a movement sensor together with the live ultrasound images.

The software provides image measurements such as prostate volume and lesion size. Information on the orientation of all images and video frames is recorded so that the same position can be found if a repeat biopsy is done. The system is PACS compatible, but Weasis DICOM viewer software is available where a PACS is not available. The ExactVu unit costs £124,958 (includes ultrasound components).

The Fusion Bx 2.0 (Focal Healthcare) is a biopsy device comprising a counterbalanced, semi-robotic arm that is mounted on a mobile cart. The system uses Fusion MR software which is compatible with third-party ultrasound systems. It uses elastic and rigid estimation to account for changes in the shape of the prostate during the procedure, and supports transrectal and transperineal biopsies. The counterbalanced semi-robotic arm can be used as a stepper for stabilised biopsies, or can allow complete freedom of movement for a freehand biopsy. All patient movements are tracked with sensors in the semi-robotic arm.

The software allows image measurements such as prostate volume and distances to be calculated. Data on the biopsied samples and the regions of interest are recorded on a 3D image of the prostate. The system can connect to a PACS using a wired ethernet or wireless connection. The software costs £24,244 (USD $30,000) and the cart costs £96,974 (USD $120,000).

The iSR'obot Mona Lisa (Biobot Surgical) is a robotic transperineal prostate biopsy system with MRI-ultrasound fusion capability. The system uses UroFusion software to highlight regions of interest on MRI images and fuses the MRI model with the ultrasound model. A robotic needle guide allows automated positioning and depth control of the biopsy needle to the targeted biopsy core. The system uses elastic estimation to account for changes in the shape of the prostate during the procedure.

Reports are generated with 3D images and coordinates are recorded for each biopsy sample. No information was received from the company on the tracking of patient movement, whether freehand biopsies can be done, PACS compatibility, image measurement capabilities, costs or confirmation of regulatory approval.

The KOELIS Trinity (KOELIS and Kebomed) is a mobile ultrasound system with mapping fusion software. It comprises PROMAP 3D‑Prostate Suite software and the Trinity ultrasound system (workstation, ultrasound probes, guides specific to transperineal or transrectal biopsies, and a probe holder). The system uses elastic and rigid estimation to account for changes in the shape of the prostate during the procedure, and supports transrectal and transperineal biopsies. It supports stabilised and freehand probe biopsies. The software identifies and compensates for patient movements and changes in the shape of the prostate during the procedure to record each core location.

The PROMAP software produces a 3D map of the prostate, recording the position of MRI lesion targets and the locations of biopsy samples. The KOELIS Trinity system provides image measurements such as prostate volume, measurements of the regions of interest and other quantitative measurements from the image. Data can be transferred to a PACS. The system costs £23,620, plus £39,948 for transrectal software, £41,754 for transperineal software, and £45,000 for the ultrasound components.

The UroNav (Phillips) comprises an electromagnetic tracking system, a mobile workstation and DynaCAD Prostate fusion software. The system is compatible with third-party ultrasound systems. It supports transperineal and transrectal biopsies, with stabilised or freehand approaches. The system uses elastic and rigid estimation methods to create 3D images to account for changes in the shape of the prostate during the procedure. The system can be used with a mobile stepper system and 2 navigation sensors to track any movement the person makes.

The UroNav system provides core location data, images and videos. It works with DynaCAD Prostate fusion software, an image analysis and reporting tool. No information was received from the company on PACS compatibility or costs.