Table 1 A breakdown of the barriers towards clinical implementation of neuroimaging CAD models presented in this article.

From: Challenges of implementing computer-aided diagnostic models for neuroimages in a clinical setting

Barrier type

Reason

Description

Solution(s)

Technical

Generalizability

Failure of CAD models to generalize across different scanner types and hospitals, as well as different population subgroups, ethnicities, ages, and genders

Federated learning, larger datasets, methods that prevent overfitting, domain switching, harmonization

 

Verifiability

A general set of problems, including the black box model, prevents users from knowing the reasons for a CAD model’s decision.

Segmentation-based models explainable AI, gradient class activations

 

Integration into workflow

Translation of models from proof-of-concept to usable software products

Investment in software engineering and user experience, corporate partnerships

 

Incomplete and mislabeled data

EHR data is often incomplete or mislabeled, hampering the training of CAD models

More careful record keeping, translating clinician notes, careful exclusion of data, and development of methods that can handle such incomplete data.

 

High computational requirements

Computational requirements for medical image computations are very high, which is expensive.

Cloud-based solutions; institutional investment in servers

Disease-related

Lack of biomarkers

Lack of consistent physiological features detectable in data that are consistently present with a particular brain disorder

Dependent on the type of disorder studied, and for some it may be insurmountable. However, higher-resolution data, different modalities, and more advanced analysis techniques may mitigate the issue.

 

Lack of sufficient modalities

Modality types used in the research world (primarily to study psychiatric disorders) are often not present in the clinic, curtailing the implementation of neuroimaging for the detection of such disorders

Inclusion of fMRI, EEG, etc. into clinical workflows

 

Disease differentiation

Emphasis on causes of the disease (e.g. whether dementia is caused by Alzheimer’s or vascularization), which is often just as important as the presence of a disease

More careful labeling of disorders and confounders, further study of ML methods beyond binary classification

 

Correlation with confounding variables

Variables for which the disorder of interest is systematically correlated with another variable regardless of the dataset; similar to generalizability (above), except different methods are required to mitigate model bias

Data matching, machine-learning-based regression methods

 

Lack of control group

Clinical data often lacks a healthy control group, against which to compare, to train CAD models

Careful data curation; reformulation of the problem, such that a control group doesn’t have to be healthy, but merely has to not have the disease of interest

Institutional

Separation of AI experts and data scientists from clinicians

Data scientists and AI experts are most often employed at sites other than hospitals, thus being separated from real-world medical data, while clinicians work in hospitals, leading to incomplete understanding on both sides

Increased postdoctoral salaries in research hospitals, stabilization of career tracks for junior biomedical researchers, specialized fellowship programs to partner AI experts with clinicians

 

Technical expertise of clinicians/Usability of CAD models

Clinicians are disinclined from using CAD models and other automated tools due to the technical skill required and the amount of time required for use

Work more closely with data scientists/AI experts, supplementary training courses; Prioritization of usability in CAD models

 

Lack of funding for implementation studies

Funding bodies are often more inclined to fund novelty studies rather than implementation studies

Different guidelines for funding bodies (e.g. NIH)

 

Disorganization of clinical databases

Related to “incomplete and mislabeled data," above. Databases in hospitals are often disorganized, hampering big-data machine-learning studies and leading to mislabeled data. Medical images are often duplicated and identifiers are often missing or difficult to match with medical images, leading to loss of clinical/demographic information for medical images.

Institutional investment clinical databases, both on the part of hospitals and vendors.

 

Federal approval processes

Federal bodies are often disinclined from approving CAD models, though much of this is a result of the above issues

Addressing many of the above problems, leading to greater confidence in the efficacy of CAD models; clarification, on the part of FDA and other regulatory bodies, of requirements for CAD model implementation and approval

 

Underdeveloped business model of medical AI

Lack of development of business model for medical AI. Who does the value accrue to, and who pays for it?

Development of AI business models in other industries and in business schools, which will likely inform the best practices for doing so in medicine.

 

Lack of capabilities for post-market surveillance

After an AI model is implemented in a hospital, what mechanisms are available to monitor their effectiveness on a large scale?

Centralized monitoring and reporting systems that do not interface with patient data directly, thus ensuring security.

  1. Technical- and disease-related challenges are discussed in the section “Challenges in designing robust CAD models for the clinic”, and institutional challenges are discussed in the section “Pathways to clinical implementation and institutional barriers”.