Diagnostics: From detection towards intervention

Treatment of a disease is not possible without the right diagnosis, which requires the use of high-end technologies. Advancements in imaging technologies have helped in early detection of several grave diseases like cancer. Here are some of the latest developments in medical imaging, its application in diagnostics & therapeutics and the likely future developments for further simplifying the diagnostic and treatment procedures.

Dr Asma Mohd Yousuf

Beginning with the discovery of X-rays in a laboratory, medical imaging today forms an indispensable part of treatment in a sterile and hi-tech environment. The technology has made significant advancements, from detecting disorders at the organ level to that at the molecular level. Advances in medical imaging assist in the early detection of cardiovascular diseases, cancers, stroke and many other disorders. Indeed, medical imaging is a boon to mankind.

Market scenario

Medical imaging is the largest sub-segment of global medical equipment market. The ageing population, rapid urbanisation, growing chronic diseases, government plans and economic recovery in emerging markets are the key factors driving industry growth.

Expressing views on the market growth for medical imaging, Dr Sanjeev J Mudakavi, Consultant Radiologist, BGS Global Hospitals, Bengaluru, says, “With the advent of medical tourism, patients from foreign countries are now coming to India for world-class healthcare facilities at significantly lesser expense. Also, in India, there is no waiting period for treatment as is the case in some of the advanced countries. Besides, with the advent of globalisation, the incomes of the citizens are on the rise; thus, today, more and more people can afford healthcare expenses even in rural areas. With fast service and economical prices, the market for imaging can be tapped in a better way.”

Medical imaging technologies, after their discovery, take a long time to reach the market. The process includes steps like discovery of technology, refinement of imaging technology, conducting animal trials and, subsequently, human trials. If the technology is proved to be safe then it is granted permission for use by the US Food and Drug Administration (USFDA), which also regulates safety and efficacy of the imaging equipment.

Imaging diagnostics

“Over the years, imaging has undergone a sea change, from simple radiographs to highly sophisticated tools such as ultrasound, Computed Tomography (CT) and, more recently, Magnetic Resonance Imaging (MRI). The advent of ultrasound has vastly changed the present day obstetric management. It is heavily relied upon and is the backbone of infertility and Assisted Reproductive Technology (ART),” avers Dr Roma Lala, Consultant Radiologist, Metropolis Laboratories, Mumbai.

Dr Harsh Merchant, Consultant Radiologist & Coordinator of Radiology, Lilavati Hospital and Research Centre, Mumbai, informs, “Medical imaging has improved by leaps and bounds, especially in the last five years. Earlier, we concentrated on the structural capabilities, but now we also consider the functional and physiological aspects and combine them with the anatomical

information.

Recent technological advances have been made in the fields of Positron Emission Tomography (PET)/CT, high-end multislice CT/dual-source CT, digital mammography, digital radiographs, etc. These advances are expected to help in detecting the abnormalities earlier, besides being more sensitive and cost effective.”

Interventional imaging

Besides making the right diagnosis, it is now possible to treat a disease with the help of medical imaging. Dr Mudakavi says, “It is certainly possible to treat few diseases by refining medical imaging techniques. For example, renal stones can be detected by ultrasonographic examination; the treatment includes breaking these stones into smaller fragments by using a concentrated beam of ultrasound – a process called lithotripsy. Interventional radiology is a form of radiology where many disorders such as aneurysms/tumours can be detected as

well as treated using various types of coils or injecting the chemotherapeutic agent directly into the tumour. Another latest advancement, known as the Gamma knife, is a form of radiosurgery without incisions.”

Prior to a major surgery, accurate localisation of the lesion is possible with imaging. It provides a ‘roadmap’ to the surgeon, according to Dr Sunila Jaggi, Consultant Radiologist, CT Scan and MRI Department, Bombay Hospital, Mumbai.

“Sometimes, the same symptoms can be caused by different diseases, such as pain in the right side lower abdomen due to appendicitis or stone in the ureter or right ovarian disease. Abdominal CT scanning has shown to reduce unnecessary appendix surgeries by 88 per cent and research demonstrates that evaluating cancer with PET scans saves unnecessary additional tests or procedures in 77 per cent of the cases,” explains Dr Mudakavi.

Medical imaging reduces the need for invasive surgeries, as it provides alternative minimally invasive image-guided treatment options. Also, by using imaging

technologies, it is now possible to plan a surgery well in advance, thereby reducing the post-operative complications.

Imaging in cancer

Imaging helps in detecting cancers in early stages, making it possible to administer adequate treatment to patients. After treatment, imaging can be used for follow-up to monitor response to treatment as well as to rule out recurrence.

“Routine screening digital mammographies, done annually or every two years after the age of 35 years in females, assist in identifying breast cancers in the initial stages. Also, in patients with a family history of colonic malignancy, virtual CT colonoscopy helps in polyp and cancer detection. Imaging can also help in better staging of cancers, eg, PET/CT can pick up metastases much better than CT in case of lung cancer. Also, contrast MRI mammography can pick up occult breast malignancy with metastatic axillary lymph nodes,” says Dr Merchant.

Dr (Col) Dinesh Kapoor, Senior Consultant and Coordinator, Department of Radiology, Indraprastha Apollo Hospitals, New Delhi, adds, “Although radiation can kill all types of cancer, patients need to be informed that healthy organs in the vicinity of the cancer can also be affected. This becomes dangerous whereby radiation, while curing cancer, can also adversely affect healthy parts of the body in the vicinity.”

Providing details on this technology, Dr (Col) Kapoor says, “With the introduction of Novalis Tx, many cancer patients will benefit from the high precision and pinpoint accuracy of the treatment. This ensures that the best possible treatment dose is delivered while damage to healthy tissue is minimised. Sophisticated image guidance and motion management tools allow Novalis Tx to perform a CT scan of targeted tissues in real-time. It is, therefore, able to pinpoint the position of tumour with every movement and move the radiation beam to deliver the required dose accurately, swiftly, safely and completely.”

Contraindications and complications

Ionising radiations also have the potential to produce harmful side effects including cancers. Dr Mudakavi says, “Exposure to these radiations should be kept As Low As Reasonably Achievable (the ALARA principle). Further safety features employed include providing dosimeters to individuals working with these modalities, which measures the amount of exposure received. For patients, the vulnerable regions such as the eyes and gonads should be protected by lead shields when possible.”

Further, Dr Merchant adds, “It is advisable to discuss with the clinical radiologist for deciding the appropriate imaging modality for particular clinical scenario so that the patients do not have to undergo unnecessary imaging. At all times, undue exposure to ionising radiation must be avoided and, where possible, alternative imaging modalities should be used.”

Affordability

Medical imaging has proven to help in saving many lives. However, like all new advanced technologies, even this comes with a price that is affordable to some but expensive to many patients. Cost could be one of the major reasons for many patients to not choose these tests, which results in either progress of the disease or increase in complications related to the disease.

Dr Mudakavi says, “Interestingly, although imaging technologies are expensive, they actually save money in the long run, in addition to their life-saving impact. According to researchers at Harvard Medical School, every $ 385 spent on imaging decreased hospital stay by one day, saving about $ 3,000 per patient.”

Dr Merchant says, “The only way that these technologies can become affordable is when manufacturing of the entire equipment, such as CT/MRI, is started in the country. Surprisingly, most of the core parts of these expensive equipment are manufactured in India, eg, CT scan tubes, generators, etc, which are then exported to the West and later on imported back as a part of the whole machine. The use of refurbished equipment also can substantially reduce the cost to patients. Also, adopting a film-less environment will substantially reduce the recurring cost.”

Further, Dr Roma Lala opines, “Cost of imaging is high. Therefore, imaging should be recommended only when required. Every imaging test undertaken should be a step forward in the diagnosis of illness. Also, certain medical ailments may preclude some imaging modalities, eg, high serum creatinine may obviate the use of contrast medium in CT scans and angiographic studies.”

However, Dr Jaggi believes that grant of government subsidies, availability of these techniques at subsidised rates in government-run hospitals as well as health insurance support could help in making medical imaging reasonably priced.

e-Imaging

Dr Mudakavi elaborates, “Today, images can be stored in CDs or pen drives. These can also be transferred through Internet for analysis and reporting at a distant centre, also known as teleradiology. The images can be integrated into the operation theatre systems to guide during the surgery by precision mapping of body tissues and tracking the position of surgical instruments or navigated surgery through detailed intraoperative imaging.”

Digital imaging has helped doctors as well as hospitals to go film-less, providing the freedom to access data from the Picture Archiving And Communication System (PACS) report remotely from anywhere in the world and, at the same time, helping the patients to access their reports from anywhere including their mobile phones. Dr Jaggi suggests, “Global acceptance and uniformity of digital imaging standards can be achieved by DICOM interaction. This facilitates formulating universal guidelines and achieving better imaging standards.”

Regulations

Dr Mudakavi says, “Global harmonisation of standards and regulatory requirements should help in the overall market growth, particularly in India and China, which are the emerging economic superpowers. Hence, there is a huge scope for improvement in this area. Regulatory bodies in India such as the National Accreditation Board for Hospitals & Healthcare Providers (NABH) lay down the standards, and certify the healthcare institutions after due inspection of facilities.”

Molecular imaging

Biomedical imaging is increasingly becoming a keystone in biomedical studies by bridging the gap between research performed and its clinical application.

Updating the benefits of molecular imaging, Dr Mudakavi says, “Molecular imaging differs from traditional imaging, as chemical probes known as biomarkers are used to help visualise particular targets or pathways. Biomarkers interact chemically with their surroundings and in turn alter the image according to molecular changes occurring within the area of interest.”

Present and future

Medical imaging has become the cornerstone of current medical practice and changed the way clinical medicine was practiced in the last century. Dr Jaggi informs, “Medical imaging has evolved tremendously over the years, since the discovery of X-rays in 1895. Faster imaging speeds of CT scanners, flat panel digital X-ray imagers, excellent quality ultrasound systems, low-dose digital mammography systems and imaging at higher field strengths on MRI have a big impact in today’s evidence-based practice, which supports/confirms clinical diagnoses. Medicine is now more clinicoradiological, the latter playing a dominant role.  In the future, more compact systems with very high resolution may be available. Tissue-specific imaging is also possible. Imaging trends in India should now focus more on subject-based subspecialty rather than being modality specific.”

Meanwhile, Dr Mudakavi points out, “The impact of medical imaging can be estimated by the fact that most of the inventors of imaging techniques have been awarded the Nobel Prize, eg, Wilhem Roentgen for discovering X-rays in 1901, Hounsfield and McCormack for CT in 1979, Mansfield and Lauterbur for MRI in 2003 and many more. The future for medical imaging research is vibrant and new technologies such as thermal imaging, microwave imaging and Terahertz rays (T-rays) are expected to further advance the imaging methodologies and improve the health of humans. Computed-aided diagnosis is another technology that is expected to reduce human error and improve accuracy of disease detection and characterisation.”

asma.yousuf@infomedia18.in

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