Dilated Cardiomyopathy in Children: Early Detection and Treatment

Photon-counting CT Can Evaluate Lung Function

New CT technology allows for a comprehensive, simultaneous evaluation of lung structure and function, something not possible with standard CT, according to a study published in Radiology, a journal of the Radiological Society of North America (RSNA).

Chest CT is the imaging method of choice for analyzing lung disease and tracking changes over time. However, CT studies of lung function and perfusion, or blood flow, require dedicated protocols that cannot be combined.

Researchers in Germany and the Netherlands developed a chest imaging protocol that yields information on structure and function of the lungs as a one-stop-shop procedure. The protocol uses recently introduced photon-counting CT technology. Photon-counting CT enables high image quality at a radiation dose below that of a standard chest CT. In addition, it provides better spatial resolution and options for spectral imaging, which uses energy information from the X-rays to characterize tissue composition. The new protocol requires advanced software but no additional hardware.

The researchers studied the protocol in 197 patients with clinically indicated CT for various known and unknown lung function impairment. After administration of an intravenous contrast agent, the photon-counting CT scan was taken when the patients inhaled. This was followed by a scan when the patients exhaled.

In 166 patients, the researchers were able to acquire all CT-derived parameters, for a success rate of 85%.

The protocol allowed for simultaneous evaluation of lung structure, ventilation, vasculature and perfusion of the parenchyma, the region of the lungs that contain the gas-exchanging alveoli. The alveoli are tiny air sacs where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and out. The protocol showed advantages over standard CT.

"The improvement in the contrast-to-noise ratio and spatial resolution of the pulmonary blood volume images was substantial," said study senior author Hoen-oh Shin, M.D., professor of radiology at the Institute of Diagnostic and Interventional Radiology at Hannover Medical School in Hannover, Germany. "In my opinion, the most important advantage is the significantly improved spectral resolution, which enables new applications such as functional imaging of the lungs with CT."

The photon-counting CT protocol has other promising applications in lung imaging. It can provide important preoperative identification of areas of emphysema and perfusion defects in patients with chronic thromboembolic pulmonary hypertension, a progressive disease caused by blood clots that do not clear from the lungs.

Postoperatively, the protocol allowed evaluation of surgical success and was helpful in assessing the lungs after lung or stem cell transplant procedures. It may also be useful in follow-up of chronic obstructive pulmonary disease and looking at pathological findings in the lung tissue.

"We believe that the proposed protocol is generally valuable for diseases with known or unknown lung function impairment," Dr. Shin said.

Representative coronal images obtained in an 82-year-old male patient with persisting shortness of breath 1 month after COVID-19 infection. Circles indicate pathology. The virtual noncontrast-enhanced images at (A) inspiration, (B) warped inspiration, and (C) expiration show areas of ground-glass opacifications in the right upper lobe, as well as emphysema in the left lung. The perfusion image (E) and the late enhancement image (F) show corresponding high values with ground-glass opacifications in the affected areas of the lung. (D) The ventilation image is heterogeneous, with areas of low to no ventilation in areas of emphysema, normal ventilation in healthy areas, and increased ventilation (ie, collapse) in the ground-glass opacifications. Exemplary measurements with region of interest in the right upper lobe are as follows: ventilation, 0.61; perfusion, 18% of vessel contrast; and late enhancement, 79% of vessel contrast. Credit: Radiological Society of North America

Dr. Shin and colleagues first applied the protocol to patients with interstitial lung disease, a group of diseases that cause progressive scarring of the lung tissue. They then expanded the applications to include post-COVID-19 condition where interstitial lung disease sometimes develops.

"With the proposed protocol, we have also been able to answer many other questions related to post-COVID-19 condition, such as the detection of acute and chronic pulmonary emboli on CT angiography, and we are currently investigating whether perfusion changes can be quantified in microvascular damage or inflammatory areas," Dr. Shin said.

The researchers are working to improve processing time and increase the robustness of the technique.

"Regional ventilation and perfusion depend on patient position and gravity, among other factors," Dr. Shin said. "Further studies are needed to assess the dependence on position and depth of breathing, as well as the reproducibility of the measurements."

More information: Sarah C. Scharm et al, Regional Pulmonary Morphology and Function: Photon-counting CT Assessment, Radiology (2023). DOI: 10.1148/radiol.230318

Citation: Photon-counting CT can evaluate lung function (2023, July 13) retrieved 20 July 2023 from https://medicalxpress.Com/news/2023-07-photon-counting-ct-lung-function.Html

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Photon-counting CT Protocol Shows Promise For Lung Imaging

New CT technology allows for a comprehensive, simultaneous evaluation of lung structure and function, something not possible with standard CT, according to a study published in Radiology, a journal of the Radiological Society of North America (RSNA).

Chest CT is the imaging method of choice for analyzing lung disease and tracking changes over time. However, CT studies of lung function and perfusion, or blood flow, require dedicated protocols that cannot be combined.

Researchers in Germany and the Netherlands developed a chest imaging protocol that yields information on structure and function of the lungs as a one-stop-shop procedure. The protocol uses recently introduced photon-counting CT technology. Photon-counting CT enables high image quality at a radiation dose below that of a standard chest CT. In addition, it provides better spatial resolution and options for spectral imaging, which uses energy information from the X-rays to characterize tissue composition. The new protocol requires advanced software but no additional hardware.

The researchers studied the protocol in 197 patients with clinically indicated CT for various known and unknown lung function impairment. After administration of an intravenous contrast agent, the photon-counting CT scan was taken when the patients inhaled. This was followed by a scan when the patients exhaled.

In 166 patients, the researchers were able to acquire all CT-derived parameters, for a success rate of 85%.

The protocol allowed for simultaneous evaluation of lung structure, ventilation, vasculature and perfusion of the parenchyma, the region of the lungs that contain the gas-exchanging alveoli. The alveoli are tiny air sacs where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and out. The protocol showed advantages over standard CT.

The improvement in the contrast-to-noise ratio and spatial resolution of the pulmonary blood volume images was substantial. In my opinion, the most important advantage is the significantly improved spectral resolution, which enables new applications such as functional imaging of the lungs with CT."

Hoen-oh Shin, M.D., study senior author, professor of radiology at the Institute of Diagnostic and Interventional Radiology at Hannover Medical School in Hannover, Germany

The photon-counting CT protocol has other promising applications in lung imaging. It can provide important preoperative identification of areas of emphysema and perfusion defects in patients with chronic thromboembolic pulmonary hypertension, a progressive disease caused by blood clots that do not clear from the lungs.

Postoperatively, the protocol allowed evaluation of surgical success and was helpful in assessing the lungs after lung or stem cell transplant procedures. It may also be useful in follow-up of chronic obstructive pulmonary disease and looking at pathological findings in the lung tissue.

"We believe that the proposed protocol is generally valuable for diseases with known or unknown lung function impairment," Dr. Shin said.

Dr. Shin and colleagues first applied the protocol to patients with interstitial lung disease, a group of diseases that cause progressive scarring of the lung tissue. They then expanded the applications to include post-COVID-19 condition where interstitial lung disease sometimes develops.

"With the proposed protocol, we have also been able to answer many other questions related to post-COVID-19 condition, such as the detection of acute and chronic pulmonary emboli on CT angiography, and we are currently investigating whether perfusion changes can be quantified in microvascular damage or inflammatory areas," Dr. Shin said.

The researchers are working to improve processing time and increase the robustness of the technique.

"Regional ventilation and perfusion depend on patient position and gravity, among other factors," Dr. Shin said. "Further studies are needed to assess the dependence on position and depth of breathing, as well as the reproducibility of the measurements."

Source:

Journal reference:

Scharm, S. C., et al. (2023) Regional Pulmonary Morphology and Function: Photon-counting CT Assessment. Radiology. Doi.Org/10.1148/radiol.230318.

Photon-Counting CT Enhances Assessment Of Lung Structure And Function

According to a study published in Radiology, new CT technology enables a thorough, concurrent evaluation of lung anatomy and function, something that is not feasible with regular CT.

Images in a 34-year-old female patient show severe smoking-associated small airway disease with patchy ground-glass opacities and mosaic pattern. The images were generated with spectral postprocessing on a coronal plane at (A) inspiration (warped for voxelwise matching with expiration), (B) ventilation, (C) perfusion, (D) expiration, (E) CT angiography, and (F) late contrast enhancement. Quantitative parameters include whole lung or lobar volume, and inspiratory (A) and expiratory (D) attenuation and functional parameters such as ventilation (B), perfusion (C), and late contrast enhancement (F). They are described using descriptive statistics or histogram analysis. Corresponding functional maps show inhomogeneous ventilation with lobular air-trapping in the lower lobes and matched perfusion inhomogeneities. CT angiography (E) and late contrast enhancement (F) images show no abnormal findings. Image Credit: https://pubs.Rsna.Org/doi/10.1148/radiol.230318 ©RSNA 2023

The best imaging technique for assessing lung disease and monitoring changes over time is chest computed tomography (CT). However, specific techniques are needed for CT studies of lung function and perfusion, which cannot be combined.

Researchers in Germany and the Netherlands created an all-in-one chest imaging approach that provides information on the anatomy and function of the lungs. The procedure employs photon-counting CT technology, which provides great image quality at a lower radiation dose than a standard chest CT.

Furthermore, it offers improved spatial resolution and spectral imaging possibilities, requiring advanced software but no additional hardware.

The technique was investigated in 197 patients with clinically indicated CT for various known and unknown lung function impairments. After an intravenous contrast agent was administered, the photon-counting CT scan was performed while the patients inhaled and again when they exhaled.

The researchers had an 85% success rate in collecting all the CT-derived parameters from 166 patients.

The procedure enabled the examination of lung anatomy, ventilation, vasculature, and parenchymal perfusion all at once. Over traditional CT, the technique has shown advantages.

The improvement in the contrast-to-noise ratio and spatial resolution of the pulmonary blood volume images was substantial. In my opinion, the most important advantage is the significantly improved spectral resolution, which enables new applications such as functional imaging of the lungs with CT.

Hoen-oh Shin, M.D., Study Senior Author and Professor, Radiology, Institute of Diagnostic and Interventional Radiology, Hannover Medical School

Other Promising Applications in Lung Imaging

Other intriguing lung imaging uses for the photon-counting CT procedure exist. In patients with chronic thromboembolic pulmonary hypertension, a progressive condition caused by blood clots that do not clear from the lungs, it can provide crucial preoperative detection of areas of emphysema and perfusion abnormalities.

The postoperative regimen helped evaluate the lungs after lung or stem cell transplant procedures and permitted the evaluation of surgical success. Additionally, it can be helpful while monitoring the progression of chronic obstructive pulmonary disease and examining pathological abnormalities in lung tissue.

Dr. Shin added, "We believe that the proposed protocol is generally valuable for diseases with known or unknown lung function impairment."

The procedure was initially used on patients with interstitial lung disease by Dr. Shin and his associates. Then, the applications were broadened to incorporate the post-COVID-19 situation, when interstitial lung disease can occasionally manifest.

Dr. Shin further stated, "With the proposed protocol, we have also been able to answer many other questions related to post-COVID-19 condition, such as the detection of acute and chronic pulmonary emboli on CT angiography, and we are currently investigating whether perfusion changes can be quantified in microvascular damage or inflammatory areas."

The researchers are striving to streamline processing time and improve the technique's robustness.

Dr. Shin concluded, "Regional ventilation and perfusion depend on patient position and gravity, among other factors. Further studies are needed to assess the dependence on position and depth of breathing, as well as the reproducibility of the measurements."

Journal Reference:

Scharm, S. C., et al. (2023) Regional Pulmonary Morphology and Function: Photon-counting CT Assessment. Radiology. Doi:10.1148/radiol.230318.

Source: https://www.Rsna.Org/

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