Management dilemma in pelvi-ureteric junction obstruction: is transit time the answer?

PURPOSE: Pelvi-ureteric junction obstruction (PUJO) is the leading cause for hydronephrosis in children. Diuretic renography used in the pre- and post-operative evaluation of pyeloplasty may not be reliable in predicting the outcome. METHODS: A prospective study was conducted from October 2018 to November 2020, including all children with unilateral PUJO undergoing Pyeloplasty. Renal diuretic renography scans done in the pre and post operative periods were assessed for transit time. The time taken for the isotope to reach the renal pelvis was noted by a single observer as the transit time, from the dynamic frames of the diuretic renogram. RESULTS: Of the 65 children, 74% were boys. The transit time (median) in the preoperative renography was 10 min, whereas the same was 4 min 45 s in the postoperative period, the decrease was statistically significant. On evaluation of transit time with ROC (receiver operating characteristics) curve, a cut-off of 4 min and 25 s was arrived at, which could identify the delayed drainage reliably. CONCLUSION: Improvement in transit time is a reliable predictor of renal function improvement after pyeloplasty, comparing favorably in relation to split renal function.

Modified Schwartz formula and 99mTc-DTPA plasma clearance methods to calculate glomerular filtration rate in critically ill children.

BACKGROUND: Studies comparing the modified Schwartz formula with measured GFR (m-GFR) are lacking in critically ill children. METHODS: This prospective cohort study enrolled children aged 1 month to 12 years, within 24 h of admission. m-GFR measured by technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) and calculated by Russell's two-sample slope-intercept method. Serum creatinine was estimated by modified Jaffe method and estimated GFR (e-GFR) calculated by modified Schwartz formula. The primary outcome was to find agreement between the two methods. Bias, precision, and accuracy were calculated. Secondary outcomes were the incidence of AKI (by p-RIFLE criteria) and the difference between the two methods to diagnose AKI. RESULTS: A total of 208 pairs were analyzed. e-GFR showed good agreement with m-GFR with a mean bias of -4.37 ml/min/1.73 m2 and precision (SD of bias) of 33.07, 95% limit of agreement -69.18 to 60.45, and intraclass correlation of 74% (95%CI 66-80%, P < 0.001). e-GFR underestimated m-GFR by 19.8% (95% CI 7.9-31.7%). Accuracy of e-GFR values within 10%, 20%, and 30% of m-GFR were 68.3%, 72.6%, and 78.8%, respectively. Incidence of AKI within 24 h was 60.1% by e-GFR and 54.3% by m-GFR (kappa 0.569, P < 0.001; sensitivity of 85.8%, 95%CI (78-91.7%). CONCLUSIONS: The modified Schwartz formula shows good agreement with 99mTc-labeled DTPA double plasma sample clearance method for calculating GFR in critically ill children aged 1 month to 12 years. The underestimation of GFR should be kept in mind while applying the formula at the bedside in PICU. TRIAL REGISTRATION: Protocol accessible at Clinical Trial Registry of India (CTRI) www.ctri.nic.in . (Trial Registered Prospectively and Registration No. CTRI/2017/10/010014) ([Registered on: 06/10/2017] Trial Registered Prospectively.) (Title "Measured glomerular filtration rate using Diethylenetriaminepentaacetic acid (DTPA) renal scan versus estimated glomerular filtration rate using modified Schwartz formula in critically ill children: A prospective observational, analytical study."). A higher resolution version of the Graphical abstract is available as Supplementary information.

Size specific dose estimate (SSDE) for estimating patient dose from CT used in myocardial perfusion SPECT/CT.

OBJECTIVES: Size specific dose estimate (SSDE) is a new parameter that includes patient size factor in its calculation. Recent studies have produced mixed results on the utility of SSDE, especially when automatic exposure control (AEC) was used. The objective of the study was to find out if there is a relationship between patient size and each of the parameters, SSDE and CTDIvol, when AEC is used. METHODS: CT data of consecutively selected 111 patients were included for analysis. CTDIvol values of the CT scans were extracted for each patient. Effective diameter of each patient was calculated as geometric mean of anteroposterior and lateral diameters measured on axial CT images. Corresponding conversion factors for effective diameters were obtained from American Association of Physicists in Medicine (AAPM) report 204. SSDE was obtained as the product of CTDIvol and conversion factor values. Linear regression model was used to evaluate the relationship between patient size and the parameters SSDE and CTDIvol. RESULTS: Mean weight was 62 (11.5) and range was 34 - 103 kg. Median CTDIvol (mGy) on AEC mode was 7.27(IQ range 7.27, 7.65) and mean effective diameter was 26.2 cm (2.4). Mean SSDE (mGy) was 10.6 (0.84). Good positive correlation was obtained between CTDIvol and effective diameter (r=0.536; p<0.0005). Strong inverse correlation was noted between SSDE and effective diameter (r=-0.777; p<0.0005). Linear regression model for establishing relationship between CTDIvol and effective diameter showed slope of 0.314mGy/cm (R=0.561; R2=0.314; P<0.0005) whereas between effective diameter and SSDE slope was -0.23mGy/cm (R=0.676; R2=0.457; P< 0.0005). CONCLUSION: The study shows that CTDIvol and SSDE vary but divergently, with patient size. SSDE is a better estimate of patient radiation dose from CT of MPI SPECT/CT than CTDIvol in systems that use automated exposure control.

Cardiovascular Risk Scores in Women Undergoing Stress Myocardial Perfusion Scan and Comparison with Scan-Predicted Risk.

BACKGROUND: Death due to cardiovascular disease is a major concern in the field of noncommunicable disease. Assessment of cardiovascular risk score using Framingham score and WHO/ISH score is a noninvasive, easier method of predicting the adverse cardiovascular event in the general population. AIMS AND OBJECTIVES: The aim of the study was to assess the cardiovascular risk using Framingham score and WHO/ISH in women undergoing stress myocardial perfusion imaging (MPI) and comparison with scan-predicted risk. MATERIALS AND METHODS: Adult females with suspected coronary artery disease referred to the department of nuclear medicine for 2 months were included in the study. Data pertaining to the risk score assessment were collected, and the risk scores were calculated. Subsequently, the patients underwent scheduled Tc-99m methoxy-isobutyl-isonitrile myocardial stress imaging, and scan-predicted risks were calculated. Then, the risk score of Framingham and WHO/ISH methods were compared with stress myocardial perfusion score using Cohen's kappa statistic. RESULTS: The mean age of the sample was 52 years (standard deviation: 11). Framingham and WHO/ISH risk scores predicted low, intermediate, and high risk in 62.2%, 28.9%, and 8.9% and 68.9%, 22.1%, and 8.89% of the population. The two scoring methods showed moderate agreement (κ =0.59). However, the scores showed only slight and fair agreement, respectively, with risk predicted by stress MPI. CONCLUSION: Although the risk scores have been shown to benefit in screening general population, they may not perform well in symptomatic patients with suspected angina. Out of the two methods, WHO/ISH fares better than Framingham score in this population.

Retrosternal Ectopic Thyroid Mimicking Esophagus in Tc-99m Pertechnetate Thyroid Scan.

Abnormal Pertechnetate distribution can occur due to many reasons such as retrosternal extension of eutopic thyroid gland, ectopic functioning thyroid gland, physiological uptake in esophagus, teratoma having functioning thyroid tissue component, metastatic lymph nodes and sequestered thyroid nodule. We present a case of thyrotoxicosis with hyper functioning thyroid gland and two abnormal foci of uptake in the mediastinum in a linear fashion that mimcked esophageal activity. These foci persisted even after consuming water. SPECT localised these foci in retrosternal and likely to be ectopic functioning thyroid. Retrosternal ectopic thyroid tissue may not usually be detected on Tc-99m scan due to attenuation of low-energy gamma rays by sternal bone. However, hyperfunctioning tissue enabled visualization of the retrosternal ectopic thyroid.

99mTc-LLEC Renal Dynamic Scan in a Patient With Pelvic Neuroblastoma.

A 5-month-old boy with ultrasonography showing bilateral hydronephrosis, referred for renal scan. On Tc-L,L,ethylenedicysteine (Tc-LLEC) renal scan, tracer blush in flow images in the region of urinary bladder was seen and tumor mass was suspected. Contrast-enhanced CT showed a soft tissue mass in sacrococcygeal region. Histopathological examination of biopsy tissue revealed malignant round cell tumor and immunohistochemistry consistent with neuroblastoma. I-MIBG scan revealed uptake in the pelvic mass with no distant metastasis.

Multiple Cutaneous Metastases on 99mTC-HYNIC-TOC Scan in a Rare Case of Malignant Laryngeal Paraganglioma.

Laryngeal paraganglioma is a rare neuroendocrine tumor arising from neural crest cells of larynx, contributing to 0.6% of the laryngeal tumors. Patients usually present with compressive symptoms such as hoarseness of voice. These tumors express somatostatin receptors, which can be imaged with radioligands such as 99mTc labeled hydrazinonicotinyl-Tyr3-octreotide (HYNIC-TOC). The percentage of malignant transformation in laryngeal paraganglioma is 2%, and they usually metastasize to lymph nodes, bone, and liver. Here, we report a 99mTc HYNIC-TOC scan of a 55-year-old male patient with recurrent laryngeal paraganglioma, who presented with painful multiple metastatic cutaneous nodules.

Oncogenic Osteomalacia: An Approach to Diagnosis with a Case Report.

Oncogenic osteomalacia, also known as tumour induced osteomalacia, is a rare paraneoplastic syndrome caused by mesenchymal tumours secreting Fibroblast Growth Factor-23 (FGF-23). The characteristic biochemical findings include hypophosphatemia and low 1,25-dihydroxy vitamin D. The differential diagnosis for hypophosphatemia are varied. We present a case of oncogenic osteomalacia in a 29-year-old female, who presented with complaints of generalized diffuse bone pain and walking difficulty for six months duration. Thus, we have discussed the approach to diagnosis in such a case.