Computed tomography

Main article: Radiology (radiation diagnostics)

How the CT scanner works

In the video below, a CT scanner test in a laboratory with the external part of this device removed. This is what happens inside at the moment the image is received.

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Advantages

Magnetic resonance imaging is no better than computer imaging. These are different methods of tomographic examination, having different capabilities and tasks. Computed tomography is cheaper than magnetic resonance, so many people think that it is worse - that is, less informative.

It really isn't. Yes, as a method, computed tomography is simpler than magnetic resonance, but each method has its own advantages. Magnetic resonance imaging does not allow you to clearly see the bones, but it gives very good "pictures" of soft tissues.

Computed tomography perfectly "sees" bones, but in relation to soft tissues it is inferior to magnetic resonance. The specific research method is chosen depending on what the attending physician wants to see.

Analysis of CT images

• Analysis of CT images

2024: Russia created the first domestic computed tomograph

At the end of August 2024, it became known that the state corporation Rosatom developed the first domestic computer tomograph based on the Russian emitter. The project is being implemented by specialists of the RuSat RDS organization. Read more here.

2023

Computed tomography triples the risk of cancer - proven by 1 million people

On November 9, 2023, specialists from the Barcelona Institute for Global Health (ISGlobal) released the results of a study indicating that computed tomography (CT) significantly increases the risk of developing malignancies. Under certain conditions, the likelihood of cancer is tripled. Read more here.

New smart CT scan as accurate as MRI scan

On October 17, 2023, Swedish researchers from the University of Gothenburg reported the development of a new technology through which computed tomography (CT) scans can in some cases become as accurate and informative as magnetic resonance imaging (MRI). The proposed solution is based on artificial intelligence algorithms.

A CT method based on the use of X-rays is more applied to assess the condition of bones and other hard tissues. In turn, MRI technology, based on the measurement of the electromagnetic response of atomic nuclei, allows the formation of an accurate layer-by-layer three-dimensional image of internal organs and soft tissues. MRI is therefore more preferable when it comes to, for example, analyzing subtle structural changes in the brain.

CT in some cases can become as accurate and informative as MRI

Specialists from the University of Gothenburg have developed new AI-based software that provides diagnostic support to radiologists and other specialists interpreting CT images. AI algorithms allow you to supplement traditional CT images with auxiliary information specific for MRI diagnostics. The proposed method could make it easier to identify signs of dementia and some other diseases.

The software is trained on images of 1,117 people, each of whom underwent a CT and MRI procedure. The study mainly involved healthy older adults and patients with various forms of dementia. The resulting AI model makes it possible to make more accurate diagnoses based on CT images, which makes it possible to increase the efficiency of primary health care departments and other medical institutions. In addition to dementia, the method can be used to diagnose other conditions, in particular normal pressure hydrocephalus.^[1]

Reducing the radiation load Russian CT technology received a US patent

On July 6, 2023, Smart Engines announced that it had patented an experimental technology in computed tomography in the United States. The development allows you to reduce the dose of radiation when diagnosing patients with COVID and other diseases. Smart Engines intends to integrate the technology into its products and promote them both in Russia and abroad. Read more here.

New CT technology pinpoints coronary heart disease in patients who used to have surgery to make diagnosis

On June 22, 2023, German scientists from the Albert and Ludwig University of Freiburg announced the development of a new ultra-high-resolution computed tomography (CT) technology. The system makes it possible to accurately detect coronary heart disease in patients who previously had to undergo surgery to make a diagnosis.

The researchers, who carried out the work under the guidance of Muhammad T. Hagar, MD (Muhammad T. Hagar), say that coronary CT angiography is highly effective for excluding coronary heart disease in patients with low or intermediate risk of the disease. However, in the high-risk group, the use of this method is difficult due to the high prevalence of coronary calcinates - calcium deposits in conjunction with other elements. In CT images, such deposits may look larger than they actually are. This leads to a distortion of the examination results and can become the cause of false positive diagnoses. A new technology developed by German researchers solves the problem.

New CT technology pinpoints coronary heart disease in patients who used to have surgery to make diagnosis

The system is based on computed tomography with photon counting mode. With more efficient X-ray recognition and minimal noise, the device provides improved resolution. This makes it possible to form clearer and more informative images. And therefore, non-invasive diagnosis of patients at high risk of coronary heart disease becomes possible.

The tests performed gave positive results. Thus, as noted, in the future, many patients will not have to undergo surgery to make a diagnosis. This will help improve their quality of life, as well as reduce the burden on medical institutions.^[2]

2022

The number of CT studies in Moscow in 5 years has grown 1.6 times

In 2022, 5.42 million CT scans were carried out in Moscow, which is 2% more than a year earlier. Relative to 2018, the figure increased 1.6 times, calculated in the analytical agency BusinesStat as part of a study, the results of which were published in May 2023. Read more here.

Increased risk of brain tumor due to CT

On December 6, 2022, CT scans used for high-precision diagnostics may increase the risk of brain tumors, according to a study published in Lancet Oncology. Irradiation in increases the risk of brain cancer in children up to five times depending on the level of irradiation.

The findings suggest that it is crucial to monitor children's exposure levels in computed tomography (CT) scans, writes a team led by Professor Michael Hauptmann, PhD, of the Brandenburg Medical School in Neuruppin.

CT scan raises risk of brain tumour

CT is a valuable diagnostic tool, but it causes significant exposure - a fact of particular concern in children. Despite initiatives such as ImageGently and recommendations from the International Commission on Radiological Protection, many CT scans can be performed unnecessarily, and dose reduction measures are not used to the extent they could, the authors wrote.

The study by Hauptmann and colleagues used data from the World Health Organization's (WHO) International Agency for Research on Cancer's EPI-CT study, which assesses the risk of developing cancer in CT scans in children and young adults. The study included information on 658,752 patients, nine European countries and 276 hospitals. Participants underwent at least one CT scan under the age of 22 between 1977 and 2014, had no past diagnosis of cancer or benign brain tumor, and did not have cancer for at least five years after the first CT scan.

The researchers calculated excess relative brain cancer risk per 100 mGy of cumulative brain irradiation dose by reconstructing organ irradiation doses using historical apparatus settings and careful sampling of CT images. The primary outcome of the study was the first reported brain cancer five years after a person underwent their first CT scan.

During a median follow-up of 5.6 years, 165 cases of brain cancer were diagnosed. The average cumulative radiation dose was 47.4 mGy among all study participants and 76 mGy among those diagnosed with brain cancer. The authors found a significant association between radiation dose and brain cancer: the excess relative risk per 100 mGy was 1.27 (at 1 as a reference).^[3]

2021

CT in conjunction with machine learning began to be used to predict serious heart problems

In early May 2021, the researchers reported that the use of machine learning in coronary CT angiography makes it possible to better predict the risk of adverse cardiac events, for example, the appearance of unstable angina.

According to the published report, quantification and characterization of atherosclerotic plaques based on machine learning allows successful stratification of the risk of coronary lesions to predict serious adverse events in the future. Routine estimates from CT angiography reflect the severity of coronary artery involvement depending on plaque location and size, as well as the severity of ischemic symptoms. But the process of evaluating these clinical data can take a long time, and machine learning greatly speeds up the procedure.

The use of machine learning in CT makes it possible to better predict the risk of adverse events from the heart

A special study involved 361 patients who underwent coronary CT angiography. The investigators then recorded serious cardiac adverse events within 90 days of examination. The team used a machine learning algorithm evaluating atherosclerotic changes and cardiovascular risk factors to predict adverse outcomes. In 8.6% of patients, serious cardiac adverse events were reported, successfully predicted by a new algorithm that demonstrated higher predictive power than conventional CT risk estimates and regression analysis.

The researchers also studied the effectiveness of the algorithm for the automatic determination of calcinates in CT scans of the chest and heart. The deep learning AI algorithm performed well compared to all other evaluation modes. The researchers concluded that machine learning could significantly improve the diagnosis and management of at-risk patients.^[4]

Announcement of the system for 3D reconstruction of injuries by CT and MRI images

In late March 2021, SFR Medical providing Great Britain police with medical evidence reports, it announced the creation of a scalable solution for three-dimensional reconstructions of injuries. More. here

2019: An elderly woman spent 6 hours in a CT scanner. She was forgotten there

In October 2019, it became known that 70-year-old Asenka Hristova spent about six hours in a computed tomograph (CT) in a Bulgarian hospital due to the negligence of a health worker. Read more here.

2018

The world record for the speed of obtaining 3D tomographic images is set

In August 2018, a world record was set for the speed of obtaining 3D tomographic images - Helmholtz-Zentrum Berlin's BESSY II system requires only 40 milliseconds per shot. The system is used to evaluate the formation of metal foam.

By creating an ultra-stable turntable that rotates around its axis at a constant speed, the researchers developed a system capable of generating 25 3D tomographic images per second. Usually such systems cost several hundred thousand dollars, and the most modern devices are capable of producing only 20 images per second.

The world record for the speed of obtaining 3D tomographic images was set - the BESSY II system of Helmholtz-Zentrum Berlin requires only 40 milliseconds per shot

The use of specialized optics for a fast CMOS camera in the preliminary stages of operation allows you to record approximately 2000 projections per second, from which a total of 25 three-dimensional tomographic images can be created.

As a demonstration, the engineers examined the granules of aluminum alloys, which, when heated, become metal foam. To do this, experts mounted a powerful infrared lamp over a metal granulate and heated the sample to about 650 ° C. A full 3D tomographic image with a spatial resolution of 2.5 micrometer (pixel size) was generated every 40 milliseconds.

Francisco Garcia-Moreno, lead researcher and deputy head of the HZB Institute of Applied Materials, noted that the purpose of the study was to assess the formation of pores in granules and the degree of variability of this process. This issue has application significance and is of particular interest to industry. Obtaining nearly 400 3D tomographic images allowed the researchers to conduct a detailed analysis of the technology.^[5]

The world's largest database of CT images with marked pathologies is available to everyone

In July 2018, the DeepLesion CT database became publicly available. The team that developed it from the clinical center of the National Institute health care USA notes that it DeepLesion is the largest database of CT images available to everyone. It included more than 32,000 annotated images from more than 10,000 clinical cases. Such extensive annotated collections of radiological images are absolutely essential for deep learning of algorithms based on artificial intelligence that must learn to recognize different lesions. More. here

CT scan causes cancer

In July 2018, Dutch scientists proved the link between computed tomography and the development of cancer. Moreover, children are at high risk. Read more here.

2017

Identification of the oldest case of cancer in Egyptian mummies

In December 2017, an international team of scientists, including a team of specialists led by professor of physical anthropology Miguel Cecilio Botella Lopez from the University of Granada, Spain, identified the oldest known cases of cancer.

Signs of cancer were detected from computed tomography (CT) scans of two mummies found in the Kubbet el-Hawa necropolis in the Egyptian city of Aswan, ScienceDaily reported.

Компьютерная томография выявила древнейший случай cancer Egyptian mummies

CT scans provide better results than traditional mummy research methods, in which a significant portion of the wrapping material and tissues of the mummy itself are lost. In addition, computed tomography allows you to obtain more accurate information about the internal structure of the mummy and detailed information about the decoration of the deceased and embalming methods.

Computed tomography showed that one of the mummies - a woman who died around 2000 BC - had breast cancer, and the second mummy - a man who died around 1800 BC - had multiple myeloma (a type of cancer that affects the bone marrow). According to scientists, both of the dead belonged to the ruling class, or at least came from wealthy families of the ancient Egyptian city of Elephantine.

As of the end of 2017, these are the oldest cases of cancer identified by scientists. The discoveries made by experts confirm that people suffered from cancer in ancient times.

The study of mummies was carried out in the radio diagnostics department of the Aswan University Hospital. For scanning, the latest generation Toshiba CT scanner was used, which allows you to receive 124 tomographic sections at the same time.

With his help, the scientists examined two more mummies of the Late Period of Ancient Egypt - a 9-year-old boy and a teenage girl. Scans showed no signs of disease in them, from which scientists suggested that the death was as a result of infections.^[6]

Differences in radiation doses in different countries

In September 2017, a study was published that showed a difference in radiation doses used in CT scans in different countries. Swiss scientists presented their findings in the online edition of the American Journal of Roentgenology.

To monitor ionizing radiation doses in CT scanners installed in American and European medical institutions, special software was used. With its help, it is planned to standardize the amount of radiation dose for all institutions without compromising the quality of diagnostics and patient health.

The author of the report, Dr. Sebastian Schindera, in an interview with AuntMinnie.com , spoke about the case when a 46-year-old woman with acute pancreatitis underwent 14 CT scans in six months. Several of these procedures could be replaced with imaging techniques that use non-ionizing radiation, but doctors simply did not realize what total exposure the patient was exposed to.

For many years, we have understood the absence and need for automated solutions that would help medical institutions visualize their standard practical methods in an easily interpreted form, "Shindera said.

The study, which covered more than 85 thousand computed tomography procedures, showed that in California hospitals and institutions controlled by the American College of Radiology, the radiation dose is on average 240% higher than in University Hospital Basel (Switzerland).

Radiation doses in CT scans in different countries and cities

The volumetric weighted CT dose index (CTDIvol) in equipment used in California for head examination is 62, which is more than the UK (60) and Basel (40), but less than Portugal (75) and Switzerland (65). You can learn more about this from the table above.^[7]

Automated abdominal CT scan

At the International Society for Computed Tomography symposium, which was held from June 4 to 7, 2017 in San Francisco (USA), a report was presented on the rapid progress in the field of automated analysis in computed tomography (CT) of the abdominal cavity.

This topic was touched upon by Dr. Ronald Summers, who is a senior researcher and radiologist at the Biomarker Analysis and Computer Diagnostics Laboratory at the American National Institutes of Health. According to him, by mid-2017, there is a rapid development of computer diagnostic systems for CT scans of various abdominal organs, lymph nodes, adipose tissue and other areas, as well as to detect pathological changes.

Example of automatic marking of CT images using in-depth training

What is the difficulty in developing a computer program that can fully interpret abdominal computed tomography? - asked Summers during his speech at the conference. - So there is complex anatomy and pathology, there are many abnormal changes and cases of disease simulation. However, by methodically recognizing each disease diagnosed by CT scanning, we can solve these problems one after another.

The development of technology in medicine has made it possible to achieve a high degree of automation in various fields. For example, programs have been created for automatic marking of vertebrae on CT scans, automatic determination and analysis of the small intestine, segmentation and volumetric analysis of vital organs, search for abnormalities in the kidneys and lymph nodes in the retroperitoneal space, as well as polyps. However, by mid-2017, a universal program was not created, which by clicking on one button will be able to provide complete information about all organs, Summers said in an interview with the publication AuntMinnie.com.

Automated pancreatic segmentation. Manual identification is highlighted in red, automated identification is highlighted in green

He and his colleagues are creating different options for using radiological images stored in PACS systems to then develop special software for automated interpretation of abdominal CT images, he said. In their project, the scientists use radiological reports and deep learning mechanisms to detect and assess abnormalities in the abdomen. The authors of the development hope that it will avoid processing millions of medical images manually. At the same time, Ronald Summers found it difficult to say how long it may take to create such software.

For about 10-15 years, researchers worked on writing high-precision algorithms that can detect polyps from medical images. More than 50 works have been written in this direction. By 2010, such a diagnostic system had been brought to a commercial level, indicating the viability of the methods used, Summers says.

It has been proven that these methods are reliable in detecting organomegaly and the spread of metastases, he noted, adding that such technologies have not yet found widespread use, although semiautomatic systems for volumetric analysis of the liver and spleen are used in hospitals.

Left: Original abdominal CT image; right: automated segmentation of calcined aortic plaque

In 2013, scientists created a program to accurately automatically detect kidney stones and conduct quantitative analysis. Experts have shown how exophytic lesions are detected using a bulge analysis in the renal cortex. The same technique is used to search for non-echophytic lesions through contrast-enhanced computed tomography.^[8]

CT scan increases childhood cancer risk

Computed tomography (CT) scans increase the risk of childhood cancer more strongly than previously thought, Australian scientists claim. This was reported by experts at the World Health Congress, held in Melbourne from April 4 to 7, reports ABC Online.

CT scans allow doctors to get a three-dimensional image of the most inaccessible corners of the body and reveal the essence of the problem. However, the ionizing radiation the patient is exposed to during CT scans can damage cells.

The cancer developed in 3,100 children who had previously had CT scans, the study found.

After studying the medical records and cases of cancer of almost 11 million Australians under the age of 19, Professor John Mathews and his team from the University of Melbourne concluded that the radiation risks of CT are more serious than previously thought, especially at an early age.

It turned out that most of the excess cancers that arose more than two years after CT scans were caused by radiation from scans.

The cancer developed in 3,100 children who had previously had CT scans, the study found. Oncology cases among such children were reported 24% more often than among children who did not undergo CT.

Also, experts found that the risk of cancer increased by 16% with each subsequent CT procedure.

We found that the younger the children were during computed tomography, the greater their risk of further cancer, "Professor Matthews said in an interview with the publication.

He also added that if the CT study was carried out in adolescence, then the risks did not increase so much.

Scientists believe this is somehow due to the process of cell renewal in the young organism.

It seems that they are more sensitive to the harmful effects of ionizing radiation, which, in the end, can lead to the development of oncology, "the specialist explained.[9]

CT scan helped identify parasite twin in 10-month-old infant

On March 25, 2017, a successful operation took place in Indonesia, during which a parasite twin discovered by computed tomography (CT) was removed from the abdominal cavity of a 10-month-old infant. Read more here.

2016: Recreating the appearance of a girl from Ancient Egypt

In late August 2016, it became known that Australian researchers, using computed tomography, 3D printing and other modern technologies, were able to reconstruct the head of a high-ranking woman in ancient Egypt who lived during the reign of the pharaohs.

Scientists at the University of Melbourne scanned the skull of the mummy, which was stored in the museum of the university, using a 3D scanner and printed an exact copy of it on a three-dimensional printer. Muscles, skin, eyes, mouth and other parts of the head were recreated on the computer. The result was a bust of a 25-year-old Egyptian woman who was named Meritamun (beloved by the god Amun).

Using CT and 3D printing, they recreated the appearance of a mummified ancient Egyptian

It is noted that computed tomography has become an almost ideal method for studying human remains due to the high detail and lack of direct contact with the object. During the scan, not a single bandage on the mummy's head was injured. Computer images made it possible to study the structure of the facial bones of the skull, measure the size and angle of inclination of the jaw, remove the parameters of the eye cavities, etc.

According to scientists, the girl could have lived about 3,500 years ago. By the fact that the mummy was wrapped in a high-quality canvas, it was concluded that Meritamun belonged to the upper class and came from a wealthy family. She died between the ages of 18 and 25. The causes of Meritamun's death at such a young age remain a mystery to scientists.

Judging by the swelling of the bone marrow, the girl suffered from anemia. The skull bones were thin and strewn with small depressions that malaria parasites could leave behind.

The tooth problems found in Meritamun may have indicated an excessive consumption of sugar, which at that time was imported into ancient Egypt after the conquest by Alexander the Great in 331 BC. It is also known that the Egyptians at that time knew how to extract honey, which could cause dental diseases.^[10]

Notes