Recurrent depressive disorder (RDD) and bipolar disorder (BD) are the most common affective disorders worldwide. However, the pathogenesis of these disorders remains far from understood. Macromolecular proton fraction (MPF) mapping is a sensitive and specific quantitative MRI method for the assessment of brain tissue myelination, but its clinical value for affective disorders remains unknown. This cross-sectional study employed fast MPF mapping on a 1.5 T MRI scanner using the single-point synthetic reference method to investigate myelin abnormalities in white matter of RDD and BD patients. ANOVA revealed a significant main effect of the group (RDD vs. BD vs. two age-matched control groups; F (3.76) = 7.42, p < 0.001, η² = 0.227). MPF values were significantly reduced in RDD versus BD patients (p < 0.001). BD showed elevated MPF compared to controls (p = 0.01). MPF levels showed significant weak-to-moderate correlations with clinical scales of affective disorders. These findings demonstrate divergent cerebral myelination patterns—hypomyelination in RDD versus an increased myelin content in BD. In conclusion, MPF mapping demonstrated a promise as a marker of myelin content changes in affective disorder.

Background. The use of modern hepatotropic contrast compounds is associated with the risk of side-effects, like accumulation of metal ions in tissues and the development of systemic pathological reactions. Therefore, currently, obtaining of high-affinity hepatotropic drugs is under investigation.Objective. There was studied the dependence of specific contrast properties of the paramagnetic complex 2-(2-carboxymethyl-(4-hexa-decyloxyphenyl-carbamoyl-methyl))-aminoethyl-(4-hexadecyl-oxyphenylcarbamoyl methyl)-aminoacetic acid with manganese — GDOF-Mn-DTPA — in magnetic resonance imaging from the administered dose of the drug. Design and methods. The dynamics of changes in the liver contrast ratio over time at different dosages of the contrast compound GDOF-Mn-DTPA was evaluated, and changes in the T1 relaxation time of liver and kidney tissue of laboratory animals (Wistar rats, more than 300 g) at different dosages of GDOF-Mn-DTPA were calculated.Results. Visual analysis of contrast-enhanced MRI scans with GDOF-Mn-DTPA already at a dose of 0.025 mmol/kg reliably visualized the accumulation of paramagnet in the liver, while further concentration of the drug in the bile ducts of animals was noted, with the actual absence of visually detectable kidney contrast. When evaluating the T1 relaxation time for the liver and kidneys, a persistent decrease in the T1 time for liver tissue was obtained for doses of 0.1, 0.05 and 0.025 mmol/kg, in particular for 0.025 mmol/kg from the initial 760 (747–755) MS to 488 (474–505) MS (p < 0.02). On the contrary, the obtained values of T1 relaxation time for kidney tissue showed no significant accumulation of the paramagnetic contrast compound GDOF-Mn-DTPA to the renal parenchyma at a dosage of 0.025 mmol / kg or lower. GDOF-Mn-DTPA showed a high degree of hepatoselectivity, with a pronounced reduced excretion through the kidneys.Conclusion. The GDOF-Mn-DTPA complex is a stable compound with a high degree of selective contrast of the hepatic parenchyma, with minimal or no renal excretion, a reliable basis for a hepatoselective contrast agent for imaging and functional studies of the liver with MRI and clinical use in the near future.

Introduction. The development and improvement of new tomographic technologies for highly sensitive imaging of lung cancer (LC) is crucial for the early detection of this disease, accurate staging and control of complex therapy.The purpose of the study. To study the possibility of using the radiopharmaceutical (rp) ¹⁹⁹TlCl for SPECT-CT imaging of LC.Material and methods. ¹⁹⁹TlCl in solution was obtained at the U-120 cyclotron (Efremov Institute of Physics and Technology, Rosatom, St. Petersburg) of the TPU Institute of Physics and Technology by the reaction of irradiation of a metal gold target with alpha particles ¹⁹⁷Au(α,2n)¹⁹⁹Tl, at an alpha particle energy of 28 MeV, with a ¹⁹⁹Tl yield of over 95%, in saline solution. The injected dose of rp was 180–185 MBq in all cases, and the scan was performed in 12–20 minutes after the injection of ¹⁹⁹TlCl. The chest SPECT was acquired as 64 planar scans per 360° rotation of the two-detector system, in a 64 × 64 matrix, with a field of view size of 40 × 40 cm, with acquisition of more than 50,000 pulses per frame, with a high-energy high-resolution collimator installed, with an energy peak of 70 keV set at a window width of 20% of the differential discriminator. The axial sections were reconstructed using the back-projection method, taking into account the depth absorption with an absorption constant of 0.12 1 / cm. The contour of the patient's body for this purpose was imported from the CT. CT of chest was carried out immediately after the SPECT, ro the 512 × 512 matrix, with a spatial resolution of 1 mm. No X-ray contrast enhancement was carried-out. All studies were performed using a combined SPECT-CT scanner Simbia T16 (Siemens Medical).We recruited 12 patients with an established diagnosis of non-small cell LC, in everybody the SPECT-CT with ¹⁹⁹Tl-chloride was employed to stage the disease. The control group comprised 7 patients who underwent a study with ¹⁹⁹Tl-chloride for non-oncological pathology, but the diagnosis was finally rejected.Results. Visually, in SPECT-CT with ¹⁹⁹TlCl in patients without tumor pathology, the accumulation in the lungs was close to background, and the image of the mediastinum was due to the normal accumulation of rp to the heart muscle. Ratio “healthy lung/myocardium” was 0.23 ± 0.05 in the control group. For the primary node of LC, this index was 0.62 ± 0.14 (p < 0.02), and for metastatically involved lymph nodes, 0.59 ± 0.16 (p < 0.05). According to the results of the individual picture of SPECT-CT with ¹⁹⁹TlCl in LC, 6 patients out of 12 had expanded radiation areas during external gamma therapy.Conclusion. ¹⁹⁹TlCl has a high affinity to the LC tumor tissue and shows high accumulation both to the primary and to metastatic LC foci. Routine use of SPECT-CT with ¹⁹⁹TlCl in LC makes sence, both in the primary diagnosis and for the staging of the disease. It is necessary to continue the study of ¹⁹⁹TlCl as rp for both ptimary diafnostic imagung of LC and also for the follow-up control of therapy.