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Retrospect on HistoScanning; an AI routinely used in diagnostic imaging for over a decade

Author and Curator: Dror Nir, PhD

3.2.7   Retrospect on HistoScanning: an AI routinely used in diagnostic imaging for over a decade, Volume 2 (Volume Two: Latest in Genomics Methodologies for Therapeutics: Gene Editing, NGS and BioInformatics, Simulations and the Genome Ontology), Part 2: CRISPR for Gene Editing and DNA Repair

This blog-post is a retrospect on over a decade of doing with HistoScanning; an AI medical-device for imaging-based tissue characterization.

Imaging-based tissue characterization by AI is offering a change in imaging paradigm; enhancing the visual information received when using diagnostic-imaging beyond that which the eye alone can see and at the same time simplifying and increasing the cost-effectiveness of patients clinical pathway.

In the case of HistoScanning, imaging is a combination of 3D-scanning by ultrasound with a real-time application of AI. The HistoScanning AI application comprises fast “patterns recognition” algorithms trained on ultrasound-scans and matched histopathology of cancer patients. It classifies millimetric tissue-volumes by identifying differences in the scattered ultrasound characterizing different mechanical and morphological properties of the different pathologies. A user-friendly interface displays the analysis results on the live ultrasound video image.

Users of AI in diagnostic-imaging of cancer patients expect it to improve their ability to:

• Detect clinically significant cancer lesions with high sensitivity and specificity
• Accurately position lesions within an organ
• Accurately estimate the lesion volume
• AND; help determine the pre-clinical level of lesion aggressiveness

The last being achieved through real-time guidance of needle biopsy towards the most suspicious locations.

Unlike most technologies that get obsolete as time passes, AI gets better. Availability of more processing power, better storage technologies, and faster memories translate to an ever-growing capacity of machines to learn. Moreover, the human-perception of AI is transforming fast from disbelief at the time HistoScanning was first launched, into total embracement.

During the last decade, 192 systems were put to use at the hands of urologists, radiologists, and gynecologists. Over 200 peer-reviewed, scientific-posters and white-papers were written by HistoScanning users sharing experiences and thoughts. Most of these papers are about HistoScanning for Prostate (PHS) which was launched as a medical-device in 2007. The real-time guided prostate-biopsy application was added to it in late 2013. I have mentioned several  of these papers in blog-posts published in this open-access website, e.g. :

Today’s fundamental challenge in Prostate cancer screening (September 2, 2012)

The unfortunate ending of the Tower of Babel construction project and its effect on modern imaging-based cancer patients’ management (October 22, 2012)

On the road to improve prostate biopsy (February 15, 2013)

Ultrasound-based Screening for Ovarian Cancer (April 28, 2013)

Imaging-Biomarkers; from discovery to validation (September 28, 2014)

For people who are developing AI applications for health-care, retrospect on HistoScanning represents an excellent opportunity to better plan the life cycle of such products and what it would take to bring it to a level of wide adoption by global health systems.

It would require many pages to cover the lessons HistoScanning could teach each and all of us in detail. I will therefore briefly discuss the highlights:

• Regulations: Clearance for HistoScanning by FDA required a PMA and was not achieved until today. The regulatory process in Europe was similar to that of ultrasound but getting harder in recent years.
• Safety: During more than a decade and many thousands of procedures, no safety issue was brought up.
• Learning curve: Many of the reports on HistoScanning conclude that in order to maximize its potential the sonographer must be experienced and well trained with using the system. Amongst else, it became clear that there is a strong correlation between the clinical added value of using HistoScanning and the quality of the ultrasound scan, which is dependant on the sonographer but also, in many cases, on the patient (e.g. his BMI)
• Patient’s attitude: PMS reviews on HistoScanning shows that patients are generally excited about the opportunity of an AI application being involved in their diagnostic process. It seems to increase their confidence in the validity of the results and there was never a case of refusal to be exposed to the analysis. Also, some of the early adopters of PHS (HistoScanning for prostate) charged their patients privately for the service and patients were happy to accept that although there was no reimbursement of such cost by their health insurance.
• Adoption by practitioners: To date, PHS did not achieve wide market adoption and users’ feedback on it are mixed, ranging from strong positive recommendation to very negative and dismissive. Close examination of the reasons for such a variety of experiences reveals that most of the reports are relying on small and largely varying samples. The reason for it being the relatively high complexity and cost of clinical trials aiming at measuring its performance. Moreover, without any available standards of assessing AI performance, what is good enough for one user can be totally insufficient for another. Realizing this led to recent efforts by some leading urologists to organize large patients’ registries related to routine-use of PHS.

The most recent peer-reviewed paper on PHS; Evaluation of Prostate HistoScanning as a Method for Targeted Biopsy in Routine Practice. Petr V. Glybochko, Yuriy G. Alyaev, Alexandr V. Amosov, German E. Krupinov, Dror Nir, Mathias Winkler, Timur M. Ganzha, European Urology Focus.

Studies PHS on statistically reasonable number (611) of patients and concluded that “Our study results support supplementing the standard schematic transrectal ultrasound-guided biopsy with a few guided cores harvested using the ultrasound-based prostate HistoScanning true targeting approach in cases for which multiparametric magnetic resonance imaging is not available.”