Estimating eGFR using serum creatinine or cystatin C in healthy Vietnamese population.

Very few studies worldwide have assessed the estimated glomerular filtration rate (eGFR) using serum cystatin C (ScysC) in comparison to the gold standard measured glomerular filtration rate (mGFR) with a gamma camera technique using 99m-Technetium-Diethylene Triaminepentoacetic Acid (99mTc-DTPA). To determine the eGFR formula with the most accurate estimate of glomerular filtration rate when compared with mGFR in a healthy population in Vietnam. We conducted a cross-sectional descriptive study of more than 100 adults without hypertension. The study subjects were examined for general characteristics and blood biochemistry tests to assess eGFR, and the glomerular filtration rate was measured using 99mTc-DTPA with the Gates technique to record mGFR. The estimated values of the eGFR formula were evaluated and compared with the actual mGFR using 99mTechnetium-DTPA. Serum creatinine (Scr) concentration showed a significant difference between males and females: 0.9 ±â€…0.1 versus 0.8 ±â€…0.1 (P < .001), while ScysC concentration did not show this difference. The mGFR in the age groups < 40, 40 to 59, and ≥ 60: 105.0 ±â€…9.9, 94.8 ±â€…8.6, and 93.4 ±â€…10.6, respectively (P < .001). The eGFR-CKD-EPI-cystatin C 2012 formula showed the highest positive correlation with mGFR (ΔGFR = -1.6, R = 0.68, P < .001). eGFR calculated using cystatin C does not require sex adjustment, whereas, for creatinine, sex adjustment is necessary. The eGFR-CKD-Epi-CysC formula showed the lowest difference and a strong correlation with mGFR.

Comparison of cystatin C-based estimated glomerular filtration rate with measured glomerular filtration rate in a pediatric cohort of patients with chronic kidney disease.

BACKGROUND: It is essential to have an accurate assessment of the renal function of patients with chronic kidney disease to monitor, treat, and predict further development of the condition. Measurement of renal function in terms of glomerular filtration rate (GFR) requires either urine or blood sampling, but especially in children, more simple methods of measurement are preferable. The main objective of this study was to examine if the estimated GFR (eGFR) calculated with different cystatin-C-based equations was comparable to the GFR measured by a radiotracer (mGFR) in pediatric patients. METHODS: In this retrospective study, 28 pediatric patients contributed with 73 pairs of measurements collected within 5 years. Bland-Altman Limits of Agreement were used to evaluate the performance and accuracy of two different cystatin-C-based estimates, the CKiDCrea-CysC and the CKiDU25 respectively, compared to an mGFR based on plasma clearance of technetium-99m-diethylenetriaminepentaacetic acid or chromium-51-ethylenediaminetetraacetic acid. RESULTS: Using the CKiDCrea-CysC equation, 58.9% of the datasets were within P10 and 87.7% were within P30. The mean difference was 4.8 mL/min/1.73m2 (standard deviation: 8.5 mL/min/1.73m2) and tended to overestimate GFR and thereby overrate the kidney function within the entire GFR range. Using the CKiDU25 equation, 53.4% were within P10 and 93.2% within P30. The mean difference was -2.9 mL/min/1.73m2 (standard deviation: 8.4 mL/min/1.73m2), but the difference varied with the GFR value. CONCLUSIONS: A cystatin-C-based eGFR provides a viable substitute for monitoring renal function in pediatric patients with chronic kidney disease. However, it has a lower accuracy than mGFR and can therefore not replace mGFR in clinical use.

Multimodal radionuclide shuntography for device patency: New procedural tips for anuncommon historical technique.

Cerebrospinal fluid (CSF) shunting is an established long-term treatment option for hydrocephalus, and is one of the most commonly performed neurosurgical procedures in western countries.Despite advances in CSF shunt design and management, its failure rates remain high and is most commonly due to obstruction and infection.Cerebrospinal fluidshunt failure diagnosis should be prompt and accurate in establishing timely if its revision is appropriate. Radionuclide shuntography with technetium-99m-diethylenetriaminepetaacetic acid (99mTc-DTPA) is a useful technique for evaluation CSF shunts and management of patients presenting with shunt-related problems, in particular it can avoid unnecessary replacement interventions. Although its execution and interpretation require specific skills, we suggest its execution for the evaluation of device's patency. We here describe the radionuclide shuntography performed with recent hybrid multimodal technologies, with a procedure customized to a complicated patient with hydrocefalus and neoplastic disease. We suggest considering radionuclide shuntography in association with conventional imaging and strongly recommend the additional performance of single photon emission computed tomography/computed tomography (SPECT/CT) because it also provides valuable information to complete the interpretation of planar images.

Impact of iodine contrast media on gamma camera-based GFR and factors affecting the difference between serum creatinine-based estimated GFR and Gate's GFR.

OBJECTIVE: We aimed to elucidate the factors underlying the difference between estimated glomerular filtration rate (eGFR) calculated from serum creatinine and Gate's GFR (gGFR) measured using technetium-99m diethylene triamine pentaacetic acid ( 99m Tc-DTPA) scintigraphy. METHODS: This study was based on consecutive patients who underwent 99m Tc-DTPA scintigraphy at our hospital between January 2021 and December 2022 and whose blood serum creatinine data were obtained on the same day as the 99m Tc-DTPA scintigraphy. Relationships between the ratio of gGFR and eGFR (gGFR/eGFR) and age, sex, BMI, visceral fat, psoas muscle index (PMI), serum blood urea nitrogen, and creatinine level were investigated based on 75 patients. Additionally, for 44 patients who had two or more follow-up DTPA studies, we compared gGFR values for studies that used iodine contrast media (ICM) for computed tomography before same-day 99m Tc-DTPA studies and those that did not in the same patients. RESULTS: Weak correlations were observed between gGFR/eGFR and PMI ( r  = 0.30), BMI ( r  = 0.24), and the visceral fat area ( r  = 0.33). Multi-regression analyses showed that gGFR/eGFR was correlated with PMI ( ß â€…= 0.34, P  < 0.01) and approached significance with the visceral fat area ( ß â€…= 0.24, P  = 0.05). A significant difference was observed in gGFR between patients who received ICM before the 99m Tc-DTPA renogram and those who did not ( P  < 0.001, eGFR 80.5 ±â€…19.0 vs. 91.7 ±â€…27.8 ml/min). CONCLUSION: ICM administration temporarily decreased gGFR, and increased muscle mass increased the difference between eGFR and gGFR values.

Application of improved glomerular filtration rate estimation by a neural network model in patients with neurogenic lower urinary tract dysfunction.

BACKGROUND: Previous studies have indicated that creatinine (Cr)-based glomerular filtration rate (GFR) estimating equations - including the new Chronic Kidney Disease Epidemiology creatinine (CKD-EPIcr) equation without race and the estimated glomerular filtration rate (eGFR) equation developed for the Chinese population - displayed suboptimal performance in patients with neurogenic lower urinary tract dysfunction (NLUTD), which limited their clinical application for detecting changes in GFR levels in all cohorts. OBJECTIVE: To develop a neural network model based on multilayer perceptron (MLP) for evaluating GFR in Chinese NLUTD patients, and compare the diagnostic performance with Cr-based multiple linear regression equations for Chinese and the CKD-EPIcr equation without race. DESIGN: Single-center, cross-sectional study of GFR estimation from serum Cr, demographic data, and clinical characteristics in Chinese patients with NLUTD. PATIENTS: A total of 204 NLUTD patients, from 27 different geographic regions of China, were selected. A random sample of 141 of these subjects was included in the training sample set, and the remaining 63 patients were included in the testing sample set. METHODS: The reference GFR (rGFR) was assessed by the technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) double plasma sample method. A neural network model based on MLP was developed to evaluate GFR in the training sample set, which was then validated in the testing sample set and compared with Cr-based GFR equations. RESULTS: The MLP-based model showed significant performance improvement in evaluating the difference, absolute difference, precision, and accuracy of GFR estimation compared with the Cr-based GFR equations. Additionally, compared with the rGFR, we found that the MLP-based model provided an acceptable level of accuracy (greater than 85%, which was within a 30% deviation from the rGFR). CONCLUSION: The MLP-based model offered significant advantages in estimating GFR in Chinese NLUTD patients, and its application could be suggested in clinical practice.

Quantitative analysis of abdominal aortic blood flow by 99mTc-DTPA renal scintigraphy in patients with heart failure.

OBJECTIVE: This study aimed to explore the characteristics of abdominal aortic blood flow in patients with heart failure (HF) using 99mTc-diethylenetriaminepentaacetic acid (DTPA) renal scintigraphy. We investigated the ability of renal scintigraphy to measure the cardiopulmonary transit time and assessed whether the time-to-peak of the abdominal aorta (TTPa) can distinguish between individuals with and without HF. METHODS: We conducted a retrospective study that included 304 and 37 patients with and without HF (controls), respectively. All participants underwent 99mTc-DTPA renal scintigraphy. The time to peak from the abdominal aorta's first-pass time-activity curve was noted and compared between the groups. The diagnostic significance of TTPa for HF was ascertained through receiver operating characteristic (ROC) analysis and logistic regression. Factors influencing the TTPa were assessed using ordered logistic regression. RESULTS: The HF group displayed a significantly prolonged TTPa than controls (18.5 [14, 27] s vs. 11 [11, 13] s). Among the HF categories, HF with reduced ejection fraction (HFrEF) exhibited the longest TTPa compared with HF with mildly reduced (HFmrEF) and preserved EF (HFpEF) (25 [17, 36.5] s vs. 17 [15, 23] s vs. 15 [11, 17] s) (P < 0.001). The ROC analysis had an area under the curve of 0.831, which underscored TTPa's independent diagnostic relevance for HF. The diagnostic precision was enhanced as left ventricular ejection fraction (LVEF) declined and HF worsened. Independent factors for TTPa included the left atrium diameter, LVEF, right atrium diameter, velocity of tricuspid regurgitation, and moderate to severe aortic regurgitation. CONCLUSIONS: Based on 99mTc-DTPA renal scintigraphy, TTPa may be used as a straightforward and non-invasive tool that can effectively distinguish patients with and without HF.

Uptake of 99m Tc-DTPA in Bone Metastases From Follicular Thyroid Carcinoma.

ABSTRACT: A 53-year-old man with follicular thyroid carcinoma (FTC) was referred for renal scintigraphy using 99m Tc-DTPA to assess the kidney function. Unexpectedly, the images showed an abnormal uptake of radiotracer in the right pelvic region. It corresponded to the site of metastasis in the right ilium revealed on 131 I SPECT/CT images. The biopsy pathology of the ilium lesion demonstrated follicular thyroid cancer.

New Multi-Parameters Combination of Technetium-99m-Diethylene-Triamine-Pentaacetate Orbital Single-Photon Emission Computed Tomography/Computed Tomography for the Evaluation of Graves' Orbitopathy Activity.

PURPOSE: This study investigates the new combined parameters of 99mTc-DTPA orbital single-photon emission computed tomography/computed tomography (SPECT/CT) for the evaluation of Graves' orbitopathy (GO) activity. METHODS: A retrospective analysis was performed on 41 patients. All the patients undergone the 99mTc-DTPA orbital SPECT/CT and were categorized into active and inactive group based on the standard combined by the clinical active score (CAS), magnet resonance imaging (MRI) and/or follow-up results. Quantitative parameters of lacrimal gland (LG) including the protruding degree of lacrimal gland herniation (LGH) and uptake ratios (URs) of region of interest (ROI) drawn on lacrimal gland and occipital bone. SPECT/CT reading results were based on visual analysis. Parameters were compared between the two groups and the diagnostic value on discrimination of GO activity was also evaluated. RESULTS: All parameters of SPECT/CT for active GO groups were significantly higher than those of the inactive groups (p<.05). There were notable linear positive correlations between the assumption standard and readings as well as combination models 2 and 3 (r = .794, r = .772, r = .760, respectively). ROC analysis indicated that model 2 provided the highest diagnostic performance, exhibiting an area under the curve (AUC) of .947, a sensitivity of 92.7%, and a specificity of 88.6%. CONCLUSIONS: The combined use of SPECT/CT reading results and DTPA uptake parameters of LG offers a more objective and precise evaluation of active GO. This study further recommends 99mTc-DTPA SPECT/CT might be serving as a supplementary beneficial approach for CAS in evaluating GO activity.

Deep learning-based attenuation correction method in 99mTc-GSA SPECT/CT hepatic imaging: a phantom study.

This study aimed to evaluate a deep learning-based attenuation correction (AC) method to generate pseudo-computed tomography (CT) images from non-AC single-photon emission computed tomography images (SPECTNC) for AC in 99mTc-galactosyl human albumin diethylenetriamine pentaacetic acid (GSA) scintigraphy and to reduce patient dosage. A cycle-consistent generative network (CycleGAN) model was used to generate pseudo-CT images. The training datasets comprised approximately 850 liver phantom images obtained from SPECTNC and real CT images. The training datasets were then input to CycleGAN, and pseudo-CT images were output. SPECT images with real-time CT attenuation correction (SPECTCTAC) and pseudo-CT attenuation correction (SPECTGAN) were acquired. The difference in liver volume between real CT and pseudo-CT images was evaluated. Total counts and uniformity were then used to evaluate the effects of AC. Additionally, the similarity coefficients of SPECTCTAC and SPECTGAN were assessed using a structural similarity (SSIM) index. The pseudo-CT images produced a lower liver volume than the real CT images. SPECTCTAC exhibited a higher total count than SPECTNC and SPECTGAN, which were approximately 60% and 7% lower, respectively. The uniformities of SPECTCTAC and SPECTGAN were better than those of SPECTNC. The mean SSIM value for SPECTCTAC and SPECTGAN was 0.97. We proposed a deep learning-based AC approach to generate pseudo-CT images from SPECTNC images in 99mTc-GSA scintigraphy. SPECTGAN with AC using pseudo-CT images was similar to SPECTCTAC, demonstrating the possibility of SPECT/CT examination with reduced exposure to radiation.

Comparison between CT volumetry, technetium99m galactosyl-serum-albumin scintigraphy, and gadoxetic-acid-enhanced MRI to estimate the liver fibrosis stage in preoperative patients.

OBJECTIVES: To compare the efficacy of computed tomography volumetry (CTV), technetium99m galactosyl-serum-albumin (99mTc-GSA) scintigraphy, and gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid-enhanced MRI (EOB-MRI) in estimating the liver fibrosis (LF) stage in patients undergoing liver resection. METHODS: This retrospective study included 91 consecutive patients who had undergone preoperative dynamic CT and 99mTc-GSA scintigraphy. EOB-MRI was performed in 76 patients. CTV was used to measure the total liver volume (TLV), spleen volume (SV), normalised to the body surface area (BSA), and liver-to-spleen volume ratio (TLV/SV). 99mTc-GSA scintigraphy provided LHL15, HH15, and GSA indices. The liver-to-spleen ratio (LSR) was calculated in the hepatobiliary phase of EOB-MRI. Hyaluronic acid and type 4 collagen levels were measured in 65 patients. Logistic regression and receiver operating characteristic (ROC) analyses were performed to identify useful parameters for estimating the LF stage and laboratory data. RESULTS: According to the multivariable logistic regression analysis, SV/BSA (odds ratio [OR], 1.01; 95% confidence interval [CI], 1.003-1.02; p = 0.011), LSR (OR, 0.06; 95%CI, 0.004-0.70; p = 0.026), and hyaluronic acid (OR, 1.01; 95%CI, 1.001-1.02; p = 0.024) were independent variables for severe LF (F3-4). Combined SV/BSA, LSR, and hyaluronic acid correctly estimated severe LF, with an AUC of 0.91, which was significantly larger than the AUCs of the GSA index (AUC = 0.84), SV/BSA (AUC = 0.83), or LSR (AUC = 0.75) alone. CONCLUSIONS: Combined CTV, EOB-MRI, and hyaluronic acid analyses improved the estimation accuracy of severe LF compared to CTV, EOB-MRI, or 99mTc-GSA scintigraphy individually. CLINICAL RELEVANCE STATEMENT: The combined analysis of spleen volume on CT volumetry, liver-to-spleen ratio on gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid-enhanced MRI, and hyaluronic acid can identify severe liver fibrosis associated with a high risk of liver failure after hepatectomy and recurrence in patients with hepatocellular carcinoma. KEY POINTS: • Spleen volume of CT volumetry normalised to the body surface area, liver-to-spleen ratio of EOB-MRI, and hyaluronic acid were independent variables for liver fibrosis. • CT volumetry and EOB-MRI enable the detection of severe liver fibrosis, which may correlate with post-hepatectomy liver failure and complications. • Combined CT volumetry, gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid-enhanced MRI (EOB-MRI), and hyaluronic acid analyses improved the estimation of severe liver fibrosis compared to technetium99m galactosyl-serum-albumin scintigraphy.

Comparing the Reliability of the Glomerular Filtration Rate Estimated with 99m-Technetium Diethylene-Triamine-Pentaacetate versus the Effective Renal Plasma Flow Obtained with 99m-Technetium Ethylene Dicysteine: A Prospective Observational Study.

The glomerular filtration rate (GFR) is important for assessing renal function and must be calculated reliably and reproducibly. This study aimed to compare the reliability and accuracy of GFR estimated with 99m-technetium diethylene-triamine-pentaacetate (99mTc-DTPA) versus that calculated from the effective renal plasma flow (ERPF) (GFR is 20% of ERPF) determined by the 99m-technetium ethylene dicysteine (99mTc-EC) technique. Forty-five patients suffering from cancer requiring platinum compound-based chemotherapy or from chronic renal failure were recruited. The patients were divided into two cohorts: (1) those with normal serum creatinine (SCr) levels (≤2 mg/dL) and (2) deranged SCr levels (>2 mg/dL). For all patients, the relative renal function was estimated by the 99mTc-DTPA and 99mTc-EC methods, 2-4 days apart. A 24-h urine sample for estimating 24-h creatinine clearance (CrCl) was obtained. GFR was also calculated using the Modification of Diet in Renal Disease (MDRD) formula. The GFR estimated via 24-h urine CrCl, 99mTc-DTPA, and ERPF obtained with 99mTc-EC were examined by quantile comparison plots, and all showed evidence of following a non-Gaussian distribution. For SCr values ≤2 mg/dL, the GFR estimated by the MDRD formula consistently shows significantly higher values than the GFR estimated with 99mTc-DTPA or 99mTc-EC. We found a high degree of correlation between the 99mTc-DTPA and 99mTc-EC radionuclide methods of estimating GFR. However, in patients with renal dysfunction, GFR estimated through Gates' method using a gamma camera overestimated the GFR; in these patients, calculating the GFR from the ERPF obtained with 99mTc-EC is more accurate.

99mTc-DTPA Renal Dynamic Imaging for Evaluating the Function of Duplex Kidneys in Adult Patients

Background: This study aimed to explore technetium-99m-diethylenetriaminepentaacetic acid (99mTc-DTPA) renal dynamicimaging to evaluate duplex kidney function in adult patients.Subjects and Methods: We retrospectively analyzed the clinical data of 25 patients with duplex kidneys who underwent 99mTc-DTPA renal dynamic imaging between June 2011 and March 2023 at our hospital. Patients in the duplex kidney group (n = 25)were divided into renogram normal (n = 9) and abnormal (n = 16) groups according to the imaging data. Additionally, normalpatients were selected as the control group (n = 25). After imaging, the region of interest of the kidneys was delineated, andrenography was performed. Renography can provide renal function parameters, including glomerular filtration rate (GFR),Tmax, T1/2, renal clearance, and the GFR ratio of the duplex renal segment (upper renal moiety).Results: Compared with the control group, the serum creatinine level in the duplex kidney group was higher (p = 0.025), GFRwas lower (p = 0.001), and patients with impaired renal function were mainly in the abnormal renography group (p = 0.001). Inthe duplex kidney group, the GFR (p = 0.026) and renal clearance (p = 0.006) of the affected kidneys were lower than those of thecontralateral kidneys, and Tmax (p = 0.025) was higher than that of the contralateral kidneys. There were no differences in renalfunction indicators of duplex renal segments with different GFR ratios. However, when the GFR ratio exceeded 50%, the renalfunction tended to decline.Conclusions: 99mTc-DTPA renal dynamic imaging was found useful to evaluate the total renal function, split renal function,and upper urinary tract patency in patients with duplex kidneys. Patients with abnormal renography results had worse renalfunction, and those with poor renal clearance in the affected renal moiety required surgical treatment. (AU)

Large Bladder Stone Detected on Renal Scintigraphy.

ABSTRACT: A 39-year-old woman with hydronephrosis underwent 99mTc-DTPA renal dynamic scintigraphy to evaluate renal function. The images revealed a central photopenic region in the urinary bladder. SPECT/CT images suggested the abnormal tracer distribution corresponding to a large urinary bladder stone.

DTPA clearance test: a sensitive method for detecting radiation-induced lung fibrosis in lung cancer patients.

OBJECTIVE: The aim of this study is to analyze the frequency of lung injury and the sensitivity of the diethylenetriamine penta-acetic acid (DTPA) clearance test in detecting lung injury in patients undergoing radiotherapy (RT) to the thorax. MATERIAL AND METHOD: Twenty individuals scheduled for RT for lung cancer were included as the patient group. The healthy control group consisted of 20 age and gender-matched individuals who were nonsmokers with no history of comorbidities. We conducted follow-up with patients at 0-1-6 months, performing carbon monoxide diffusion test (DLCO), DTPA clearance test (excluding the first month), and high-resolution computed tomography of the thorax. The control group was followed up with DLCO between the baseline and 6th months. RESULTS: Ninety percent of the patient group was male, and the median age was 62 years. Seventy percent of the patients had squamous cell carcinoma and adenocarcinoma. Pneumonitis was detected in the patient group in the first month (100%) and fibrosis in the sixth month (%100) Both at the beginning and in the sixth month, the DLCO values of patients who received RT were lower than those of the control group ( P  = 0.001 and P  < 0.001, respectively). While DTPA clearance was similar between irradiated and non-radiated lungs at the beginning, there was a substantial decrease in the irradiated lung in the sixth month( P  = 0.001). There was no significant correlation between malignancy type, RT dose, and tumor size( P  > 0.05). CONCLUSION: The DTPA clearance test could be an alternative method for demonstrating radiation injury in patients receiving RT.

Thyroid Accumulation of 99m Tc-DTPA in Graves Disease.

ABSTRACT: 99m Tc-DTPA dynamic renal scintigraphy for evaluating glomerular filtration rate was performed in a 29-year-old woman with hyperuricemia and Graves disease. Subsequently, 99m Tc-DTPA orbital scintigraphy was conducted to determine the activity of Graves ophthalmopathy. Thyroid accumulation of 99m Tc-DTPA was incidentally identified. This should be cautiously distinguished from 99m Tc-pertechnetate uptake, considering that the salivary glands, oral cavity, and stomach were not visualized. Our case demonstrates that augmentation of blood supply, enhancement of capillary permeability, and accumulation of inflammatory exudate may be involved in the pathological process of Graves disease.

Incidental Detection of Ilium Langerhans Cell Histiocytosis on 99m Tc-DTPA Renal Dynamic Scintigraphy.

ABSTRACT: We report the case of a 24-year-old man who underwent 99m Tc-DTPA scintigraphy for the evaluation the renal function. This scan incidentally showed an abnormal uptake of 99m Tc-DTPA in the left lower abdominal region. SPECT/CT fusion images showed osteolytic bone destruction in the left ilium associated with soft tissue mass and elevated DTPA uptake. Biopsy pathology of the ilium lesion demonstrated Langerhans cell histiocytosis.

Scintigraphic Diagnosis of Acute Pulmonary Embolism: From Basics to Best Practices.

In this article the technique, interpretation, and diagnostic performance of scintigraphy for the diagnosis of acute pulmonary embolism (PE) are reviewed. Lung scintigraphy has stood the test of time as a reliable and validated examination for the determination of PE. Ventilation/perfusion (V/Q) lung scintigraphy assesses the functional consequences of the clot on its downstream vascular bed in conjunction with the underlying ventilatory status of the affected lung region, in contrast to CT pulmonary angiography (CTPA), which visualizes presence of the clot within affected vessels. Most-commonly used ventilation radiopharmaceuticals are Technetium-99m labeled aerosols (such as 99mTechnetium-DTPA), or ultrafine particle suspensions (99mTc-Technegas) which reach the distal lung in proportion to regional distribution of ventilation. Perfusion images are obtained after intravenous administration 99mTc-labeled macro-aggregated albumin particles which lodge in the distal pulmonary capillaries. Both planar and tomographic methods of imaging, each favored in different geographical regions, will be described. Guidelines for interpretation of scintigraphy have been issues by both the Society of Nuclear Medicine and Molecular Imaging, and by the European Association of Nuclear Medicine. Breast tissue is particularly radiosensitive during pregnancy due to its highly proliferative state and many guidelines recommend use of lung scintigraphy rather than CTPA in this population. Several maneuvers are available in order to further reduce radiation exposure including reducing radiopharmaceutical dosages or omitting ventilation altogether, functionally converting the study to a low-dose screening examination; if perfusion defects are present, further testing is necessary. Several groups have also performed perfusion-only studies during the COVID epidemic in order to reduce risk of respiratory contagion. In patients where perfusion defects are present, further testing is again necessary to avoid false-positive results. Improved availability of personal protective equipment, and reduced risk of serious infection, have rendered this maneuver moot in most practices. First introduced 60 years ago, subsequent advances in radiopharmaceutical development and imaging methods have positioned lung scintigraphy to continue to play an important clinical and research role in the diagnosis of acute PE.

Comparison of 99mTc-DTPA and 51Cr-EDTA for glomerular filtration rate measurement with the continuous infusion method.

BACKGROUND: In late 2018, the production of 51Chromium-labelled ethylenediamine tetra-acetic acid (51Cr-EDTA), a validated and widely used radio-isotopic tracer for measuring glomerular filtration rate, was halted. Technetium-99m-diethylenetriaminepentaacetic acid (99mTc-DTPA) has been validated for GFR measurement with a single bolus injection, a procedure not suitable in patients with extracellular compartment hyperhydration. In such cases, a bolus followed by continuous infusion of the tracer is required. The aim of this study was to evaluate whether 99mTc-DTPA with the infusion protocol can replace 51Cr-EDTA for GFR measurement. METHODS: We conducted a prospective single centre study during February and March 2019. All patients referred for GFR measurement received both radiotracers simultaneously: 51Cr-EDTA and 99mTc-DTPA bolus and continuous infusion were administered concomitantly through the same intravenous route. Over four and a half hours, plasma and urine samples were collected to calculate urinary and plasma clearance. RESULTS: Twenty-two patients were included (mean age 63.4 ± 17.5 years; 68% men). Mean urinary clearance of 51Cr-EDTA and 99mTc-DTPA was 52.4 ± 22.5 mL/min and 52.8 ± 22.6 mL/min, respectively (p = 0.47), with a mean bias of 0.39 ± 2.50 mL/min, an accuracy within 10% of 100% (95% CI 100; 100) and a Pearson correlation coefficient of 0.994. Mean plasma clearance of 51Cr-EDTA and 99mTc-DTPA was 54.8 ± 20.9 mL/min and 54.4 ± 20.9 mL/min, respectively (p = 0.61), with a mean bias of - 0.43 ± 3.89 mL/min, an accuracy within 10% of 77% (95% CI 59; 91) and a Pearson correlation coefficient of 0.983. CONCLUSIONS: Urinary and plasma clearance of 99mTc-DTPA can be used with the infusion protocol to measure GFR.

Reproducibility of Computed Tomography Volumetry for Predicting Post-Donation Remnant Renal Function: A Retrospective Analysis.

BACKGROUND: Recent studies indicate that split renal function calculated by computed tomography (CT) volumetry is equally or more useful than that calculated by nuclear renography for donated kidney side selection. However, it remains unclear if CT volumetry accurately reflects split renal function as measured by nuclear renography. Therefore, this study aimed to evaluate the reproducibility of CT volumetry. METHODS: Data from 141 donors who underwent living donor nephrectomy at Nara Medical University from March 2007 to June 2021 were reviewed. The correlation and agreement between the predicted postdonation estimated glomerular filtration rate (eGFR) by 99mTc-diethylenetriamine penta-acetic acid (DTPA) scintigraphy and by CT volumetry were evaluated by the Pearson's correlation coefficient and Bland-Altman analysis, respectively. Moreover, a comparison in split renal function categorization between 99mTc-DTPA scan and CT volumetry was performed. RESULTS: A total of 133 donors were included in the analysis. There was high correlation between the predicted postdonation eGFR by 99mTc-DTPA scintigraphy and by CT. Moreover, there was agreement in the predicted postdonation eGFR between 99mTc-DTPA scintigraphy and CT volumetry (Bland-Altman analysis [bias, 95% limits of agreement]; 0.83%, -5.6% to 7.3%). However, in one of 17 donors with absolute split renal function greater than 10% by 99mTc-DTPA scintigraphy, this clinically significant difference was missed by CT volumetry. CONCLUSION: There are donors for whom a clinically significant split renal function is not accurately reflected in CT volumetry. Future studies need to amend this discrepancy.