OPEN MEDSCIENCE | August 13, 2025
Abstract: Medical imaging has become one of the most important advances in healthcare over the past 125 years, profoundly changing how diseases are diagnosed, treated, and prevented. Since Wilhelm Conrad Röntgen’s discovery of the X-ray in 1895, imaging technologies have expanded dramatically, allowing clinicians to view anatomical structures, physiological functions, and molecular activity with remarkable precision. Today, imaging is embedded throughout the patient care pathway—from early detection and screening to guiding treatment, monitoring response, and supporting long-term follow-up.
Modalities and Clinical Applications
This mini review outlines the historical development, fundamental principles, and clinical applications of key imaging modalities, including X-ray, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, positron emission tomography (PET), and newer hybrid and molecular techniques. It discusses the contribution of imaging to screening and early diagnosis of major conditions such as cancer, cardiovascular disease, and neurological disorders, with a focus on its impact on public health outcomes.
Imaging in Precision Medicine and Multidisciplinary Care
The review highlights how imaging supports multidisciplinary care and precision medicine by improving diagnostic accuracy and disease characterisation. It also examines its role in directing therapeutic procedures—from image-guided biopsies and minimally invasive interventions to complex surgery and targeted radiotherapy—and in tracking disease progression and response to treatment.
Emerging Technologies and Ethical Considerations
Innovative developments such as artificial intelligence (AI), photon-counting CT, targeted molecular tracers, theranostics, portable imaging devices, and advanced visualisation tools are explored, along with ethical, regulatory, and accessibility challenges. Topics such as radiation exposure, overdiagnosis, data protection, and inequalities in access—especially between high-income and resource-limited settings—are considered.
Future Directions: Imaging in Preventive and Personalised Care
Looking ahead, the review considers how imaging will underpin future models of preventive, personalised, and participatory healthcare, aided by AI and remote diagnostic capabilities. By combining historical insight with technical and clinical perspectives, it demonstrates how imaging has evolved from a passive diagnostic aid into an active, integral component of modern medicine and public health.
Keywords: Early Detection, Diagnostic Accuracy, Treatment Guidance, Emerging Technologies, Patient Access, Ethical Considerations.
1. Early Detection and Screening
Historical Context and Evolution
The concept of early detection through imaging is grounded in the principle that identifying disease before symptoms arise allows for less invasive, more effective treatment, and ultimately better outcomes. The first documented case of imaging for detection dates to the winter of 1895–1896, when Röntgen’s X-ray technology revealed a bullet lodged in a patient’s leg. By the 1920s, chest X-rays were being used to screen for pulmonary tuberculosis, reducing community transmission and improving survival rates.
From the mid-twentieth century onwards, population screening programmes began incorporating dedicated imaging protocols. These were initially focused on specific diseases such as breast cancer, and later expanded to other conditions with substantial public health impact.
Cancer Screening
Breast cancer screening with mammography is one of the most studied imaging-based public health interventions. The introduction of screen-film mammography in the 1960s enabled radiologists to detect cancers smaller than 1 cm in diameter — well before they became palpable. Landmark trials, including the Swedish Two-County Trial, reported mortality reductions of up to 30% in women aged 50–69 who underwent regular screening.
Modern full-field digital mammography (FFDM) provides improved spatial and contrast resolution, while digital breast tomosynthesis (DBT) reconstructs the breast in thin slices, reducing the problem of tissue overlap. In the UK’s National Health Service Breast Screening Programme (NHSBSP), mammography is offered every three years to women aged 50–71, and early detection rates have increased significantly since DBT adoption.
Lung cancer, the leading cause of cancer death worldwide, has benefited from LDCT screening in high-risk populations. The US National Lung Screening Trial (NLST) demonstrated a 20% reduction in lung cancer mortality compared with chest radiography in long-term smokers aged 55–74. The UK Lung Health Check programme has adopted a mobile LDCT approach, delivering scans in community settings such as supermarket car parks to reach underserved populations.
Colorectal cancer screening increasingly incorporates CT colonography (virtual colonoscopy) as a non-invasive alternative to conventional colonoscopy. Studies have shown sensitivity rates exceeding 90% for polyps larger than 10 mm, supporting its role in both symptomatic and screening cohorts.
Cardiovascular Screening
Cardiovascular disease is the leading cause of death globally, and imaging plays an essential role in its early detection. Coronary artery calcium (CAC) scoring by non-contrast CT provides a quantifiable measure of atherosclerotic burden, with scores above 300 indicating a high risk of future cardiac events. Carotid duplex ultrasound measures intima–media thickness and detects plaques, supporting stroke prevention strategies.
In congenital heart disease, foetal echocardiography has enabled prenatal detection, allowing delivery in specialist centres and immediate postnatal intervention, improving survival and reducing morbidity.
Neurological Screening
In neurodegenerative diseases, imaging detects structural and metabolic changes years before clinical symptoms appear. Volumetric MRI can reveal hippocampal atrophy in early Alzheimer’s disease, while PET with amyloid or tau tracers confirms underlying pathology. In Parkinson’s disease, dopamine transporter SPECT differentiates degenerative from non-degenerative tremor disorders.
Balancing Benefit and Harm
Screening programmes must weigh benefits against risks such as false positives, overdiagnosis, and radiation exposure. For example, LDCT delivers a low but cumulative radiation dose, so screening is typically restricted to individuals at the highest risk. Public health agencies, including the UK National Screening Committee, review evidence regularly to adjust screening criteria and ensure net population benefit.
2. Diagnostic Accuracy and Disease Characterisation
The Shift from Detection to Precision
While early detection identifies a potential problem, diagnostic accuracy ensures that clinicians can define it with precision. Historically, this transition from suspicion to certainty relied on invasive techniques — surgical biopsies, exploratory operations, and post-mortem confirmation. The progression of medical imaging over the past century has progressively replaced many of these methods, providing accurate, reproducible, and non-invasive diagnoses.
The mid-twentieth century saw planar X-ray expand into more specialised forms, such as contrast-enhanced studies of the gastrointestinal and vascular systems. By the 1970s, computed tomography (CT), pioneered by Godfrey Hounsfield and Allan Cormack, allowed cross-sectional imaging of soft tissues with unprecedented clarity. This capability revolutionised neurological diagnosis, enabling clear visualisation of intracranial haemorrhage, infarction, and tumours without craniotomy.
CT and Its Clinical Breadth
Modern multidetector CT (MDCT) offers rapid volumetric scanning, with sub-millimetre resolution enabling fine anatomical detail. In trauma settings, CT has become indispensable for identifying internal bleeding, fractures, and organ injury in the “golden hour” of emergency care. In oncology, CT provides critical staging information — detecting lymphadenopathy, distant metastases, and tumour invasion into adjacent structures.
Cardiovascular CT, particularly CT coronary angiography (CTCA), has emerged as a frontline tool for assessing chest pain. The UK’s National Institute for Health and Care Excellence (NICE) now recommends CTCA as the initial investigation for stable chest pain of suspected cardiac origin, reflecting its high negative predictive value and ability to visualise both calcified and non-calcified plaque.
MRI: Beyond Anatomy
Magnetic resonance imaging (MRI), developed in the late 1970s and clinically adopted in the 1980s, is distinguished by its ability to differentiate soft tissues without ionising radiation. By exploiting differences in tissue relaxation times (T1 and T2), MRI can produce high-contrast images ideal for neuroimaging, musculoskeletal evaluation, and oncological assessment.
Functional MRI (fMRI), diffusion-weighted imaging (DWI), and magnetic resonance spectroscopy (MRS) extend MRI into physiological and metabolic domains. fMRI, in particular, has been transformative in neurosurgical planning, mapping eloquent cortex involved in speech, movement, and sensation to minimise post-operative deficits. DWI is now standard in acute stroke protocols, detecting cytotoxic oedema within minutes and allowing for rapid thrombolytic intervention.
In liver imaging, multiparametric MRI combining T2-weighted, DWI, and hepatocyte-specific contrast agents improves the detection and characterisation of focal lesions, differentiating benign haemangiomas from hepatocellular carcinoma.
Ultrasound: Real-Time Versatility
Ultrasound’s portability, real-time capability, and absence of ionising radiation make it invaluable in many diagnostic pathways. In obstetrics, it not only confirms pregnancy but monitors foetal growth, amniotic fluid volume, and placental health throughout gestation. In abdominal imaging, ultrasound can detect gallstones, assess hepatic parenchyma, and guide needle placement for biopsy or drainage.
Vascular ultrasound, including Doppler techniques, allows non-invasive assessment of arterial stenosis, venous thrombosis, and haemodynamic changes. Musculoskeletal ultrasound provides dynamic evaluation of tendon injuries, joint effusions, and nerve entrapments, sometimes offering higher spatial resolution than MRI for superficial structures.
Nuclear Medicine and PET
Nuclear medicine techniques add a functional layer to diagnostic imaging by using radiopharmaceuticals that target specific physiological processes. Positron emission tomography (PET) is particularly valuable in oncology, where 18F-FDG highlights areas of increased glucose metabolism typical of many tumours. PET-CT combines this metabolic information with anatomical localisation, improving sensitivity and specificity for detecting metastases and recurrence.
In cardiology, myocardial perfusion scintigraphy evaluates blood flow to the heart muscle under stress and rest conditions, guiding decisions about revascularisation. Neurological PET tracers, including amyloid-binding agents, are advancing research into Alzheimer’s disease, potentially enabling earlier diagnosis and tracking of disease progression.
The Multidisciplinary Interface
Diagnostic accuracy in modern medicine is often achieved through multidisciplinary team (MDT) meetings, where radiologists present imaging findings alongside histopathology, laboratory results, and clinical data. In oncology, this approach ensures that staging, treatment planning, and prognosis are based on the most comprehensive information available. Imaging is increasingly central to these discussions, providing objective evidence that can be compared over time to measure treatment impact.
3. Guidance of Treatment and Interventions
The Role of Imaging in the Therapeutic Era
While early imaging served primarily a diagnostic function, the past four decades have seen it evolve into an active participant in therapy. Imaging is now used to plan interventions, guide their execution in real time, and verify outcomes before the patient leaves the operating theatre. This has fundamentally changed surgical and interventional practice, shifting many procedures from open operations to minimally invasive techniques with lower morbidity and shorter recovery times.
Interventional Radiology: The Imaging-Driven Speciality
Interventional radiology (IR) emerged in the late 1960s with the pioneering work of Charles Dotter, who performed the first percutaneous transluminal angioplasty under fluoroscopic guidance. Today, IR encompasses a vast range of procedures guided by fluoroscopy, ultrasound, CT, and increasingly, MRI.
Standard IR procedures include:
Biopsies: Core or fine-needle aspiration biopsies guided by CT or ultrasound have replaced many surgical biopsies, reducing complication rates and cost. For example, CT-guided lung biopsies allow sampling of peripheral nodules that would otherwise require thoracotomy.
Drainage: Image-guided placement of catheters to drain abscesses or pleural effusions is safer and less invasive than open drainage.
Tumour Ablation: Radiofrequency ablation (RFA), microwave ablation (MWA), and cryoablation use thermal or freezing energy delivered via probes positioned under image guidance. CT ensures accurate targeting and monitoring of ablation zones.
Vascular Interventions
Fluoroscopy remains the mainstay for vascular procedures, often supplemented by intravascular ultrasound (IVUS) or optical coherence tomography (OCT) for detailed vessel assessment.
Angioplasty and Stenting: CT angiography (CTA) and MR angiography (MRA) define the anatomy before intervention, while fluoroscopy guides the actual stent deployment.
Embolisation: Used in conditions from gastrointestinal bleeding to uterine fibroids, embolisation relies on precise delivery of occlusive agents to target vessels. Pre-procedural CT or MRI maps vascular territories, while fluoroscopy confirms catheter placement and embolic distribution.
Surgical Planning and Intraoperative Imaging
In surgery, the planning phase is now heavily imaging-dependent. Neurosurgeons use high-resolution MRI and CT angiography to map tumours, vascular malformations, and functional brain areas before craniotomy. Advanced software can fuse MRI and PET data to delineate tumour margins more accurately.
Orthopaedic surgery benefits from 3D CT reconstructions for complex fractures, enabling precise pre-operative planning of fixation strategies. For joint replacements, CT-based navigation systems improve implant alignment and reduce revision rates.
Intraoperative imaging has further improved surgical precision. Cone-beam CT in orthopaedic theatres verifies hardware placement before wound closure, reducing the need for re-operation. In neurosurgery, intraoperative MRI ensures maximal tumour resection while preserving eloquent brain regions.
Image-Guided Radiotherapy
Radiotherapy relies on imaging for every stage of treatment. Planning CT scans define tumour boundaries and organs at risk, while PET-CT and MRI provide additional information on tumour biology and margins.
Image-guided radiotherapy (IGRT) uses daily imaging to align the patient and tumour precisely before each fraction, compensating for anatomical shifts. Adaptive radiotherapy goes further, re-planning treatment mid-course if significant changes occur, such as tumour shrinkage or patient weight loss.
Non-Invasive Therapies Guided by Imaging
MRI-guided focused ultrasound (MRgFUS) represents a non-invasive alternative for certain tumours and functional disorders. In uterine fibroid treatment, MRgFUS avoids the need for hysterectomy, preserving fertility in selected patients. In neurology, it can treat essential tremor by ablating a small thalamic target without incision or radiation.
Case Example
Consider a patient with hepatocellular carcinoma (HCC) unsuitable for surgery due to comorbidities. Imaging enables a combined therapeutic approach:
Pre-treatment MRI defines tumour size, location, and relationship to vascular structures.
Interventional radiologists perform transarterial chemoembolisation (TACE) under fluoroscopic guidance, delivering chemotherapy directly to the tumour’s blood supply.
Follow-up MRI evaluates necrosis and residual tumour viability, guiding repeat TACE or adjunctive ablation.
This integration of imaging into therapy exemplifies its modern role — no longer just an observer, but an active participant in treatment.
4. Monitoring Treatment Response and Disease Progression
Imaging as a Longitudinal Tool
Once treatment begins, the role of imaging shifts from detection and diagnosis to monitoring — both to evaluate therapeutic effectiveness and to detect recurrence or complications. This function has grown in importance with the rise of targeted therapies, immunotherapies, and complex multi-modality treatment regimens, where response may not always correlate with simple changes in tumour size.
Oncology: From RECIST to Functional Imaging
In cancer care, the Response Evaluation Criteria in Solid Tumours (RECIST) standardised how tumour response is measured on CT and MRI, focusing on changes in the longest diameter of target lesions. While useful for chemotherapy response, RECIST is less effective for newer treatments. Immunotherapy, for example, can trigger “pseudoprogression” — temporary tumour enlargement due to immune cell infiltration before eventual shrinkage.
Functional imaging overcomes some of these limitations. 18F-FDG PET detects changes in tumour metabolism, sometimes within days of therapy initiation. A drop in standardised uptake value (SUV) can indicate a positive response long before anatomical shrinkage occurs. This has been demonstrated in lymphoma, where PET negativity after two cycles of chemotherapy predicts long-term remission.
MRI also contributes to functional monitoring. Diffusion-weighted imaging (DWI) measures the movement of water molecules in tissue; reduced cellular density from tumour necrosis increases the apparent diffusion coefficient (ADC), providing an early marker of treatment effect. Perfusion MRI assesses changes in blood flow within tumours, often reflecting anti-angiogenic therapy impact.
Neurology: Chronic Disease Tracking
In multiple sclerosis (MS), MRI is the gold standard for monitoring disease activity. New or enlarging T2 lesions or gadolinium-enhancing lesions indicate active inflammation, guiding adjustments to disease-modifying therapy. The ability to detect subclinical disease activity means that treatment decisions can be proactive rather than reactive.
Neuro-oncology uses multiparametric MRI to distinguish tumour recurrence from treatment-related changes such as radiation necrosis. Combining DWI, perfusion, and MR spectroscopy improves diagnostic confidence.
Cardiology and Vascular Disease
In heart failure, echocardiography tracks left ventricular ejection fraction (LVEF), wall motion abnormalities, and valve function over time. Cardiac MRI provides more accurate and reproducible measurements, with late gadolinium enhancement identifying myocardial fibrosis, which carries prognostic significance.
Aortic aneurysms are monitored with CT angiography or ultrasound to assess diameter changes; intervention thresholds are typically set at 5.5 cm for the abdominal aorta, though rapid growth may prompt earlier repair.
Post-revascularisation, duplex ultrasound confirms vessel patency and detects restenosis before symptoms recur.
Musculoskeletal and Infection Follow-Up
In orthopaedics, serial imaging assesses fracture healing, implant integrity, and complications such as loosening or infection. Ultrasound can track synovitis in rheumatoid arthritis, allowing rheumatologists to fine-tune immunosuppressive regimens.
For infections such as osteomyelitis, MRI is sensitive for detecting residual marrow oedema and abscesses after antibiotic therapy. Serial imaging confirms resolution before stopping treatment.
Radiomics and Quantitative Imaging
Emerging techniques such as radiomics and machine learning–based quantitative analysis extract high-dimensional data from images, identifying patterns beyond human perception. These may predict response or progression earlier than conventional imaging, offering a bridge to truly personalised treatment planning.
5. Emerging Technologies and Innovations
Artificial Intelligence in Imaging
Artificial intelligence is transforming every stage of imaging, from acquisition to interpretation. Algorithms can:
Automate lesion detection and segmentation.
Reduce noise and improve image quality, enabling lower radiation doses.
Prioritise abnormal studies in reporting queues.
Predict histopathological characteristics from imaging features (“virtual biopsy”).
In mammography, AI systems match or surpass experienced radiologists in cancer detection while reducing false positives. In chest CT, AI detects subtle lung nodules, emphysema patterns, and coronary calcification.
Hybrid and Molecular Imaging
Hybrid modalities like PET-MRI combine metabolic sensitivity with superior soft-tissue contrast, particularly useful in paediatric oncology and neuro-oncology, where radiation minimisation is critical. Photon-counting CT represents the next generation, offering spectral information for better tissue characterisation at reduced doses.
Molecular imaging is expanding rapidly. PSMA PET has revolutionised prostate cancer staging, detecting metastases at lower PSA levels than conventional imaging. Theranostics — pairing diagnostic and therapeutic radionuclides targeting the same molecular structure — are in clinical use for neuroendocrine tumours (68Ga/177Lu-DOTATATE) and prostate cancer (68Ga/177Lu-PSMA).
Portable and Point-of-Care Imaging
Handheld ultrasound systems linked to smartphones are now used in ambulances, rural clinics, and disaster zones. Portable CT and low-field MRI units are emerging for intensive care and field settings, reducing the need for patient transport.
Advanced Visualisation
Augmented reality (AR) and virtual reality (VR) are enhancing surgical navigation, allowing real-time overlay of imaging data onto the operative field. 3D printing from imaging datasets creates patient-specific models for complex surgical planning.
Integration with Genomics and Wearables
Future imaging may be dynamically linked with genomic and proteomic data, creating a complete biological profile of each patient. Wearable devices could trigger imaging based on detected physiological changes, integrating imaging into continuous health monitoring.
6. Ethical, Regulatory, and Accessibility Considerations
Radiation Safety
Ionising radiation carries a small but cumulative risk. While modern protocols have significantly reduced doses, especially in CT and interventional procedures, the ALARA (As Low As Reasonably Achievable) principle underpins all radiological practice. Paediatric imaging demands particular care, with preference for non-ionising modalities like MRI and ultrasound when appropriate.
Overdiagnosis and Incidental Findings
The sensitivity of modern imaging means that incidental findings (“incidentalomas”) are common. While some lead to early detection of serious disease, many are benign and can trigger unnecessary tests, costs, and patient anxiety. Evidence-based guidelines are essential for balanced management.
Data Privacy and AI Governance
The rise of cloud storage, AI analytics, and cross-institutional data sharing brings risks of data breaches and misuse. Regulatory frameworks in the UK (GDPR) and the EU set strict rules for patient data handling. AI tools must be transparent, explainable, and validated across diverse populations to avoid bias.
Global Access Disparities
In high-income countries, advanced imaging is widely available, but rural areas may face delays due to workforce shortages. In low- and middle-income countries, access is often limited to basic X-ray and ultrasound. Initiatives by WHO and NGOs are deploying portable imaging and tele-radiology to bridge this gap, but sustainable training and maintenance programmes are vital.
7. The Future Impact on Patient-Centred Healthcare
From Episodic to Continuous Care
Imaging will increasingly be integrated into preventive health models. AI-powered triage systems may detect subtle changes on routine scans, triggering early intervention. Portable scanners could be used in GP surgeries, pharmacies, or even at home.
Personalised Imaging Protocols
Risk-adapted protocols will balance diagnostic benefit with safety, tailoring scan frequency, modality, and parameters to the individual. This is already seen in cancer survivorship plans, where follow-up imaging is personalised based on recurrence risk.
Theranostics and Targeted Therapy
Theranostic imaging will blur the line between diagnosis and treatment. A single molecular agent could both identify and destroy cancer cells, with imaging used to monitor therapy in real time.
Enhanced Patient Engagement
Interactive imaging reports, patient-accessible portals, and AI-generated visual explanations will empower patients to understand their conditions and participate in care decisions.
Equity and Sustainability
The challenge will be ensuring that innovations reach all who need them, without widening existing disparities. Sustainable models for equipment deployment, training, and maintenance will be as important as technological advances.
In conclusion, medical imaging has progressed from the groundbreaking first X-ray to an indispensable pillar of modern healthcare, shaping prevention, diagnosis, treatment, and long-term disease management. Its evolution has not only transformed how clinicians see inside the human body but has also redefined the very nature of patient care — shifting from reactive intervention to proactive, patient-centred strategies. As technology advances, innovations such as AI-driven analysis, hybrid and molecular imaging, theranostics, and portable systems promise earlier detection, more precise interventions, and personalised follow-up, while also extending the reach of imaging into underserved settings. The future of imaging will depend as much on addressing ethical, safety, and accessibility challenges as on developing new capabilities, ensuring that progress benefits all populations. Ultimately, imaging is no longer a silent observer of disease but an active, integrated force in promoting health and wellbeing across the global community.
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How to cite: Open MedScience (2025) The Role of Medical Imaging in Health and Wellbeing. Available at: https://www.openmedscience.com/the-role-of-medical-imaging (Accessed: 13 August 2025).
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