RU2350269C1 - Method of sections images combination of multispiral computer tomography and single-photon emission computer tomography of lungs - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention concerns medicine, namely radiology and nuclear medicine. Before carrying out of a single-photon emission computer tomography on area of an average third of clavicle establish a radioactive label. Carry out a multispiral computer tomography. Then combine a radioactive label and a section of an average third of the clavicle, received on a computer tomograph in coronal and sagittal projections . From the obtained gammagrams and tomograms build 3-D image of lungs.

EFFECT: method provides reception of the combined images of MSCT and SPECT sections on the standard equipment, raises accuracy of diagnostics of lungs diseases.

1 ex, 2 cl, 4 dwg

Description

The invention relates to medicine, namely to x-ray radiology, and can be used to obtain combined images of sections of multispiral computed tomography (MSCT) and single-photon emission computed tomography (SPECT) used in the diagnosis of lung diseases.

The SPECT method is known, which allows the scintigrams obtained to evaluate perfusion function in general and in any part of the lung, which gives an idea of the nature of blood flow dysfunctions, their prevalence, severity and activity of the pathological process (Kazuyoshi S., Norihiko K., Naofumi M., et al. Relative preservation of peripheral lung function in smoking related pulmonary emphysema: assessment with Tc-99m - MAA perfusion and dynamic Xe-133 SPECT // European Journal of Nuclear Medicine. 2000. - Vol. 27, N 7. - P. 800-806). However, the method does not allow visualization of the pulmonary parenchyma and mediastinal organs.

The known MSCT method, which allows you to obtain a tomographic image of the anatomy of an organ, accurate quantitative information about the size, spatial location, density characteristics of organs and tissues (Suga K., Kavakamii Y., Matunada N. Mechanism of lung mosaic attenuation on X-ray computed tomography in pulmonary artery occlusion diseases; comprehensive assessment with Breath hold SPECT-CT Fusion images.//92 ^nd Scientific assembly and annual meeting of the Radiological Society of North America. - 2006. - P.889). However, it is impossible to assess the microcirculatory function of the lungs.

The closest to the claimed method in terms of technical nature and the result obtained is the SPECT / CT multimodal method, which allows simultaneously combining X-ray computed tomography and registration of gamma-ray coincidence signals in SPECT, mapping CT and SPECT images (Hasegawa Bruce HC SPECT and SPECT / CT. // 92 ^nd Scientific assembly and annual meeting of the Radiological Society of North America. - 2006. - P.171). In this case, in addition to the intravenous administration of Tc-99m microspheres as a source of radionuclide radiation, an iodine-containing contrast medium is additionally injected intravenously to improve the visualization of vascular structures. The method is implemented on devices Symbia TruePoint SPECT-CT (Siemens), Philips Precedence SPECT-CT.

The disadvantages of this method include the following:

- the complexity and low availability of the apparatus that implements this method, which makes it inaccessible to most medical diagnostic institutions in Russia, including due to its high cost;

- A large number of technical, secondary and medical staff;

- difficulties associated with the simultaneous administration of a radionulide and radiopaque substance intravenously. In addition, the bolus administration of a contrast medium can cause both nephrotoxic effects and promote the development of alveolar and interstitial changes in the lung tissue due to its toxic and immune effects, especially in patients with disseminated lung diseases.

The technical result achieved by the invention is to obtain combined images of slices of MSCT and SPECT on standard equipment available in a hospital without the use of additional expensive equipment.

The invention consists in achieving the technical result in a method of combining images of slices of multi-helical computed tomography and single-photon emission computed tomography of the lungs, according to which, before conducting single-photon emission computed tomography, a radioactive mark is placed on the middle third of the clavicle, multi-helical computed tomography is performed and then combined into coronal and sagittal projections of a radioactive label and a slice of the middle third of the clavicle s obtained by computed tomography.

To combine, it is advisable to reduce the obtained matrix of slices to the same dimension and construct and combine a three-dimensional image of the lungs from the obtained scintigrams and tomograms.

To synchronize the SPECT and MSCT images, the authors proposed to establish a radioactive label on the region of the middle third of the clavicle. This area optimally allows you to calculate the number of tomographic sections with a set thickness (0.5 cm) and corresponds to the topical localization of the tips of the lungs.

In order to most accurately combine the obtained slicing matrices when carrying out two different methods (radiological - MSCT and radiological - SPECT), they must be reduced to the same dimension.

Two-dimensional matrix slices obtained in the coronal and sagittal projections, are combined with each other relative to the location of the radioactive label on the slice obtained on the gamma camera and obtained on a computer tomography slice of the middle third of the clavicle. When combining coronal and sagittal sections, axial sections are also combined. The level of slices obtained is determined by combining the radioactive label on SPECT and the middle third of the clavicle on MSCT. Subsequently, a three-dimensional image of the lungs is constructed from the obtained scintigrams on a gamma camera and three-dimensional images of the lungs are also constructed from the tomograms obtained on a computer tomograph. The obtained three-dimensional images of the lungs on SPECT and MSCT are combined.

Figure 1 presents the image of a radioactive label located on the middle third of the clavicle in a combined three-dimensional image of the lungs, figure 2 shows an axial section of the lungs on a single-photon computed tomograph, where sections of reduced blood flow are visible, figure 3 shows an axial section of the lungs on a computed tomography at the same level as in SPECT, where the areas of the greatest lesion of the pulmonary parenchyma are visible, Fig. 4 shows a combined image of an axial section of the lungs.

The study is carried out in two stages: one on a gamma camera, the other on a multispiral computed tomograph. There is no fundamental difference in the sequence of these steps. This is an important advantage of the proposed method, because sometimes it is sufficient for the diagnosis of one study and you can refuse another, which helps to reduce economic costs, radiation load on the patient, as well as the rational use of equipment.

The method is carried out, for example, as follows.

At stage 1, the patient is performed SPECT on a two-detector gamma camera Philips Forte 2005 (USA). A radiopharmaceutical (RP) is introduced intravenously, which is a large protein particle labeled with a radionuclide (gamma emitter) and causing temporary embolization of the arterio-capillary channel of the lungs at a dose of 1.0-1.5 mBq per 1 kg of body weight of the subject. For subsequent synchronization of the SPECT and MSCT images, a radioactive label 1 is set (2 mBq-Tc 99m) to the region of the middle third of the clavicle (Fig. 1).

The study begins immediately after the injection of the radiopharmaceutical. The patient is examined in the supine position in the Total Body mode (continuous scanning of a part of the body or the whole body) for 10-12 minutes using the Lung Spect program, in the position of the detectors 180 degrees, the elliptical orbit, 32 azimuths, 40 seconds at an angle. Processing the study is possible with arbitrary placement of layers from 0.5 to 2.0 cm, using a high-frequency filter Furye transformations according to the method of Henning or Batterword. Two-detector scanning allows you to obtain a layered polypositional image of the lungs in longitudinal, lateral and transverse sections with the subsequent reconstruction of a three-dimensional image.

At stage 2, MSCT is performed on a four-slice computer tomograph "Asteion", firm "Toshiba" (Japan). The patient is examined in a supine position with his hands behind his head, without a gantry tilt, in a craniocaudal direction, with a breath hold on a calm breath. The voltage is 120 kW, the exposure of one slice is 90 mA s, the pitch of the spiral (pitch) is 3.5, the thickness of the slice is 0.5 cm, the reconstruction increment is 3 mm.

At stage 3, the combination of computed tomographic scans of MSCT and SPECT is performed at the workstation of the gamma camera. For the most accurate alignment, the obtained slice matrices lead to the same dimension 256 × 256, due to the software of the gamma camera. Two-dimensional matrix slices obtained in the coronal and sagittal projections are combined with each other, combining the radioactive label on the slice obtained on the gamma camera and the slice of the middle third of the clavicle obtained on a computer tomograph. When combining coronal and sagittal sections, axial sections are automatically aligned. The level of sections obtained is determined by combining the radioactive label on SPECT and the middle third of the clavicle on MSCT. Subsequently, a three-dimensional image of the lungs is constructed from the obtained matrixes of sections on both MSCT and SPECT. The obtained three-dimensional images of the lungs on SPECT and MSCT are combined.

The method is illustrated by the following clinical example.

Patient A., born in 1939, was admitted to the department of pulmonology on an emergency basis with complaints of weakness, increasing shortness of breath, and an increase in body temperature. A history of hemoptysis occurred. To exclude pulmonary embolism (pulmonary embolism), lung SPECT was performed with preliminary radioactive labeling (2 mBq) 1 on the region of the middle third of the clavicle (Fig. 1). The study was carried out according to standard methods. According to a radiological study revealed a decrease in perfusion in the right lung in the projection S 6, 10 and in the cloak section of the upper lobes both on the right and on the left. In the projection S 4, 5 of both lungs, perfusion defects 2 were revealed, similar in shape to triangular (Fig. 2). Preliminary diagnosis: Thromboembolism of small branches of the pulmonary artery, indirect signs of bronchial obstruction.

When computed tomographic examination of the organs of the chest cavity with further construction of the image reformation in the region of the apices of both lungs, subpleural layers were determined. In S 4, 5 of both lungs, more to the right, the expanded lumens of the bronchi with densified walls 3 were determined (Fig. 3), multiple bronchioles 4, filled with contents, were also visualized, creating a symptom of a “tree in the kidneys" (Fig. 3). The airiness of the lung tissue was also diffusely increased in all parts of the lung due to panlobular and centriacinar emphysema 5 (Fig. 3).

Despite the fact that MSCT of the lungs is the most popular method for the morphological diagnosis of lung tissue diseases, however, even performing the study in angiographic mode does not make it possible to fully diagnose pulmonary embolism of small branches of the pulmonary artery (segmental and subsegmental), which is due to the technical capabilities of a four-slice CT scan. It was necessary to carry out a combined study to compare the localization of pathological changes detected in MSCT and areas with impaired blood flow.

The two-dimensional matrixes of SPECT and MSCT slices obtained in the coronal and sagittal projections were combined with each other relative to the location of the radioactive label on the slice obtained on the gamma camera and the slice of the middle third of the clavicle on a computer tomograph. When combining coronal and sagittal sections, axial sections were automatically combined. The level of sections obtained was determined by combining the radioactive label on SPECT and the middle third of the clavicle on MSCT. On the combined image of coronal, sagittal and axial sections of the lungs, an image of zones with impaired blood flow was obtained in comparison with changes in the pulmonary parenchyma.

The combination of SPECT and computed tomography (Fig. 4) revealed a morphological substrate of perfusion changes that were nonspecific and could initially correspond to both pulmonary embolism and chronic obstructive pulmonary disease, and were caused by the ongoing inflammatory reaction, which manifested itself as bronchiolitis (detected with MSCT) and accompanying vasculitis. Also, perfusion defects coincided with areas of the most pronounced emphysematous reconstruction of the lung tissue. The diagnosis of pulmonary embolism was withdrawn.

The patient was prescribed anti-inflammatory treatment, against which the complaints quickly regressed, and the patient was discharged from the hospital in a satisfactory condition.

The claimed method was applied in 16 patients. Patients were admitted for examination with suspicion of: thromboembolism of small branches of the pulmonary artery - 12 people (all patients were associated with concomitant pathology - chronic obstructive pulmonary disease, coronary heart disease); chronic obstructive pulmonary disease - 4 people (concomitant pathology - pulmonary embolism). A positive result was to increase the accuracy of diagnosis of lung diseases due to a comprehensive analysis of morphological changes in the lung tissue and microcirculation disorders. In 9 patients with chronic obstructive pulmonary pathology and with suspected thromboembolism of small branches of the pulmonary artery, areas of emphysematic bloating of the lung tissue were revealed in places of reduced blood flow, as well as areas with impaired blood flow, where there were no violations in the lung tissue, indicating violations in vascular bed of the lungs. Thus, in patients with chronic obstructive pathology, the diagnosis of thromboembolism of small branches of the pulmonary artery was confirmed. In 3 patients with bullous changes in the lung tissue and with reduced blood flow in these same areas, no additional areas with reduced blood flow were detected. The diagnosis of pulmonary embolism was withdrawn.

In 3 patients with chronic obstructive pulmonary disease who underwent surgery to reduce lung volume, combined sections revealed microcirculation disorders in areas with bullous lung tissue remodeling, and there was no blood flow in the projection of the removed lung zones. The diagnosis of pulmonary embolism was withdrawn.

Using the inventive method provides obtaining combined images of sections of MSCT and SPECT on standard equipment, improves the accuracy of diagnosis of lung diseases.

Claims (2)

1. A method of combining images of slices of multispiral computed tomography and single-photon emission computed tomography of the lungs, including installing on the region of the middle third of the clavicle a radioactive label before conducting single-photon emission computed tomography, performing multispiral computed tomography and subsequent combining in the coronal and sagittal projections of the radioactive mark and a slice of the middle third clavicle obtained by computed tomography. 2. The method according to claim 1, characterized in that for combining the obtained slices lead to the same dimension, from the obtained scintigrams and tomograms build and combine a 3-dimensional image of the lungs.

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