Comparison of 99mTc-DMSA renal scintigraphy with biochemical and histopathological findings in animal models of acute kidney injury

Biochemical and histological assays are currently used for the diagnosis and characterization of kidney injury. The purpose of this study was to compare technetium- 99m-labeled dimercaptosuccinic acid (99mTc- DMSA) renal scintigraphy, as a non-invasive method, with common biochemical and histopathological methods in two animal models of acute kidney injury. Nephrotoxicity was induced either by gentamicin (100 mg/kg/day for one week) or unilateral ureteral ligation (UUO). Renal scintigraphy was performed 1 h after intravenous injection of 99mTc-DMSA (3 mCi). Furthermore, plasma levels of blood urea nitrogen (BUN), creatinine, sodium, and potassium were determined using an autoanalyzer. At the end of experiments, kidneys were excised for the measurement of activity uptake (mCi/gr) using a dose calibrator as well as histopathological examinations with hematoxylin and eosin (H&E) staining. There was a significant decrease in 99mTc-DMSA uptake in both gentamicin (P value = 0.049) and UUO (P value = 0.034) groups, and it was more significant in the former. The levels of BUN and creatinine increased in both gentamicin and UUO groups, while the levels of sodium and potassium remained unchanged. Furthermore, a strong correlation was found between DMSA uptake and histopathological findings. Scintigraphy with 99mTc-DMSA is capable of detection of kidney injury in both gentamicin and UUO groups. Moreover, a significant correlation was found between scintigraphy parameters and histopathological findings. This suggests 99mTc-DMSA as a non-invasive method for the evaluation of kidney injury induced by drugs or anatomical disorders

Review of biomedical Čerenkov luminescence imaging applications

Abstract: Čerenkov radiation is a fascinating optical signal, which has been exploited for unique diagnostic biological sensing and imaging, with significantly expanded use just in the last half decade. Čerenkov Luminescence Imaging (CLI) has desirable capabilities for niche applications, using specially designed measurement systems that report on radiation distributions, radiotracer and nanoparticle concentrations, and are directly applied to procedures such as medicine assessment, endoscopy, surgery, quality assurance and dosimetry. When compared to the other imaging tools such as PET and SPECT, CLI can have the key advantage of lower cost, higher throughput and lower imaging time. CLI can also provide imaging and dosimetry information from both radioisotopes and linear accelerator irradiation. The relatively short range of optical photon transport in tissue means that direct Čerenkov luminescence imaging is restricted to small animals or near surface human use. Use of Čerenkov-excitation for additional molecular probes, is now emerging as a key tool for biosensing or radiosensitization. This review evaluates these new improvements in CLI for both medical value and biological insigh

Assessment of the maximum uptake time of 99mTc-DMSA in renal scintigraphy in rat

Introduction: The optimal imaging time of a radionuclide scintigraphy is the time at which the organ of interest has the maximum uptake of the injected radionuclide. This study was performed to investigate the maximum uptake time of 99mTc-DMSA in rat renal scan. Methods: Renal scintigraphy was performed with 3 mCi of 99mTc-DMSA. Planar images were acquired every 20 minutes for 8 hours post-injection using a small-animal SPECT. Results: Activity and the count rate per pixel (CRPP) of the kidneys peaked 1 h post-injection, plateaued for about 1 h, and declined time-dependently. Kidney to background ratio (KBR) reached to 61.7% at 1 h after injection and remained almost constant afterwards. Conclusion: The kidneys had maximum emission and CRPP between 1 to 2 h after 99mTc-DMSA injection, whereas there was no significant difference between the KBRs after 1 h. Our results showed that image acquisition of 1-2 h post-injection is recommended for renal scintigraphy with DMSA in rat

Effects of intrathecal opioids use in cesarean section on breastfeeding and newborns’ weight gaining

Objective: To assess the association between intrapartum intrathecal opioid use and breastfeeding and weight gain following cesarean section. Materials and methods: The prospective double-blinded study was conducted on term pregnant women, undergoing elective cesarean section under spinal anesthesia. They divided into two groups. In the first group, intrathecal Morphine was used to achieve analgesia during or after the operation. The remainder divided into two subgroups, those who did not receive any opioid or those received systemic opioids. Following labor breastfeeding accessed in a follow-up, two month latter. Results: There was no difference between the demographic variables of the mothers and newborns APGAR score and weight at the time of birth. Breastfeeding rate was similar in intrathecal group in compare with other patents (P value = 0.518). While, the infants’ weight at the end of second month was lower in spinal opioid group (P value = 0.036). Conclusion: The present study was the first to suggest that spinal (intrathecal) opioids do not have any impact on breastfeeding. However the relationship between spinal anesthesia on weight gaining needs more investigation

The Effect of Electromagnetic Field Generated by a Mobile Phone on the Performance of a SPECT Scanner

Purpose: The aim of the current attempt was quantitative investigation of the electromagnetic interference (EMI) of amobile phonewith the function of a SPECT gamma camera during data acquisition. Materials and Methods:We tested the effect of a mobile phone, in both ringing mode and standby mode, on one SPECT gamma camera during scanning a cylindrical phantom containing 5.4 mCi 99mTc. The experiment was performed for different distances of 10, 12, 14, 16, 18, 20, 25, and 30 cm betweenmobile phone and head of the scanner, and for different head angles of 0, 30, 60, 90, 120, 150, and 180 degrees. A RF-EMF meter measured strength of electromagnetic field throughout the study. Statistically significant decrease in count number was considered to be electromagnetic interference. Results: There was significant reduction in the recorded counts during ringing of the mobile phone in all studied distances. For gamma camera, fixed at a distance, there was no uniform pattern of reduction of the counts at different angles between two operation modes of the mobile phone. Conclusions: A mobile phone, at close distance, can be a sensible source of electromagnetic field, disturbing the normal function of a gamma camera

Implementation of absolute quantification in small-animal SPECT imaging: Phantom and animal studies

Purpose: Presence of photon attenuation severely challenges quantitative accuracy in single-photon emission computed tomography (SPECT) imaging. Subsequently, various attenuation correction methods have been developed to compensate for this degradation. The present study aims to implement an attenuation correction method and then to evaluate quantification accuracy of attenuation correction in small-animal SPECT imaging. Methods: Images were reconstructed using an iterative reconstruction method based on the maximum-likelihood expectation maximization (MLEM) algorithm including resolution recovery. This was implemented in our designed dedicated small-animal SPECT (HiReSPECT) system. For accurate quantification, the voxel values were converted to activity concentration via a calculated calibration factor. An attenuation correction algorithm was developed based on the first-order Chang’s method. Both phantom study and experimental measurements with four rats were used in order to validate the proposed method. Results: The phantom experiments showed that the error of �15.5% in the estimation of activity concentration in a uniform region was reduced to +5.1% when attenuation correction was applied. For in vivo studies, the average quantitative error of �22.8 � 6.3% (ranging from �31.2% to �14.8%) in the uncorrected images was reduced to +3.5 � 6.7% (ranging from �6.7 to +9.8%) after applying attenuation correction. Conclusion: The results indicate that the proposed attenuation correction algorithm based on the first-order Chang’s method, as implemented in our dedicated small-animal SPECT system, significantly improves accuracy of the quantitative analysis as well as the absolute quantification

Implementation of absolute quantification in small-animal SPECT imaging: Phantom and animal studies

Purpose: Presence of photon attenuation severely challenges quantitative accuracy in single-photon emission computed tomography (SPECT) imaging. Subsequently, various attenuation correction methods have been developed to compensate for this degradation. The present study aims to implement an attenuation correction method and then to evaluate quantification accuracy of attenuation correction in small-animal SPECT imaging. Methods: Images were reconstructed using an iterative reconstruction method based on the maximum-likelihood expectation maximization (MLEM) algorithm including resolution recovery. This was implemented in our designed dedicated small-animal SPECT (HiReSPECT) system. For accurate quantification, the voxel values were converted to activity concentration via a calculated calibration factor. An attenuation correction algorithm was developed based on the first-order Chang’s method. Both phantom study and experimental measurements with four rats were used in order to validate the proposed method. Results: The phantom experiments showed that the error of �15.5% in the estimation of activity concentration in a uniform region was reduced to +5.1% when attenuation correction was applied. For in vivo studies, the average quantitative error of �22.8 � 6.3% (ranging from �31.2% to �14.8%) in the uncorrected images was reduced to +3.5 � 6.7% (ranging from �6.7 to +9.8%) after applying attenuation correction. Conclusion: The results indicate that the proposed attenuation correction algorithm based on the first-order Chang’s method, as implemented in our dedicated small-animal SPECT system, significantly improves accuracy of the quantitative analysis as well as the absolute quantification

Serological, pathological and scintigraphic assessment of Hemiscorpius lepturus effects on renal dysfunction in rats

Objective(s): Hemiscorpius lepturus is one of the dangerous scorpions of Iran leading to acute kidney injury (AKI) especially in infants. The purpose of this animal study was to compare the serological, pathological and scintigraphic data to quickly predict the occurrence of this disorder.Materials and Methods: In two groups of animals, each contained five rats, H. lepturus venom (1200 µg/Kg) were injected intravenously via the tail vein. At three hours and one week later, 99m Tc-DMSA (3 mCi) was intravenously injected and renal scintigraphy was performed after an hour. Moreover, plasma levels of creatinine, sodium, potassium, and blood urea nitrogen (BUN) were measured. At the end of the study, renal tissues were excised and prepared to perform pathological evaluation after Hematoxylin and Eosin staining.Results: All serological indices were remained unchanged compared to control. A large number of glomerular fibrin thrombi with entrapped red blood cells and simplified tubular epithelium in dilated and ectatic tubules were observed in high power field (×100) four hours after envenomation, which reduced significantly one week later. In our scintigraphic study, there was a statistically significant difference (

Calculation of standardized uptake values (SUVs) and time activity curves (TACs) of mice in FDG-PET

Positron Emission Tomography (PET) with 18Ffluorodeoxyglucose (FDG) is an important imaging practice in cancer diagnosis, staging, treatment planning, and response assessment. Accurate interpretation of PET results requires an understanding of FDG uptake in organs. The time activity curve (TAC) and standardized uptake value (SUV) are the two common tools to measure tracer uptake in regions of interest. The TAC provides information on glucose consumption dynamics, while the SUV involves measuring the amount of tracer taken up by a specific region or volume of interest, and then adjusting the measurement by the amount of tracer injected and the subject’s characteristics. In the current study, we measured the TACs and SUVs of the heart, brain, kidney, and muscle in ten mice injected with FDG over a period of 120 minutes. According to the TACs obtained in this study, the brain has a slower uptake than the other organs with a tendency to keep the FDG for a longer period of time. Also, the SUV of the brain showed a rising trend until the middle of the experiment with a sharp falloff afterwards. The pattern of the curves of the other three organs was almost the same. The findings of this study were in agreement with a similar study on humans and are explained by the metabolic activity and physiology of the organs studied

Fetal Laceration Injury at Caesarean Delivery

 Objective: The purpose of this study was to investigate the incidence, type, location, and risk factors of accidental fetal lacerations during caesarean delivery. Material and Methods: Total deliveries, caesarean deliveries, and neonatal records for documented accidental fetal lacerations were reviewed retrospectively in four university hospital. Thegestational age, the presenting part of the fetus, the type of incision, and maternal age and parity were recorded. Caesarean deliveries were divided into elective and emergency procedures. Fetal lacerations were grouped according to the location and the need for surgical intervention. Results: Of 19217 deliveries, 8840 women were delivered by caesarean birth (46%). Neonatal records documented 87 accidental fetal lacerations. Of these accidental lacerations, 16 needed surgical repair and 62 recovered by dressing. Head and neck was the most common site of laceration (64.1%). The overall rate of accidental fetal laceration per caesarean delivery was 0.88%. The rate of emergency caesarean was 45 (56.69%) and for elective procedures was 33 (42.4%). The risk for fetal accidental laceration was higher in foetuses who underwent emergency caesarean birth (P<0.001). Conclusion: Fetal accidental laceration may occur during caesarean delivery and its incidence is significantly higher during emergency caesarean delivery. The patient should be counselled about the occurrence of fetal laceration during caesarean delivery to avoid litigation