INTRODUCTIONThis study aimed to ascertain whether nonopacified kidney on excretory urography (also known as intravenous urography [IVU]) indicates nonsalvageability.

METHODSWe retrospectively reviewed 45 adult patients with chronic unilateral urinary tract obstruction, in whom IVU revealed nonopacified kidney on one side but normal excretion on the contralateral side. Affected kidneys with split glomerular filtration rate (GFR) < 10 mL/min/1.73 m2 on 99mTc-diethylenetriaminepentaacetic acid diuretic renal scintigraphy were considered nonsalvageable. Non-function was defined based on cutoff points (< 15% and < 20%) to determine the sensitivity and specificity of differential renal function. Differences in IVU and renal scintigraphy findings, with respect to the duration of delayed filming on IVU, were analysed for significance.

RESULTSThe results of IVU and renal scintigraphy findings for 34 (75.6%) nonopacified kidneys matched, representing nonsalvageable kidneys. Sensitivity and specificity of differential renal function were 76% and 100%, respectively, when the cutoff point for non-function was set at < 15%. Sensitivity and specificity were 97% and 82%, respectively, when the cutoff point was < 20%. There was no significant difference between renal scintigraphy findings and IVU with 2-hour and > 2-hour delayed films (p = 0.96).

CONCLUSIONAlthough most nonopacified kidneys on IVU were nonsalvageable, a quarter of them were found to be salvageable on renal scintigraphy. Besides split GFR, differential function at cutoff point < 15% could be used to determine non-function of a chronic obstructed kidney when the contralateral kidney is normal. Delayed filming beyond two hours appears unnecessary in ensuring non-excretion on IVU.

Adult ; Aged ; Aged, 80 and over ; Chronic Disease ; Female ; Glomerular Filtration Rate ; Humans ; Kidney ; diagnostic imaging ; Kidney Diseases ; diagnostic imaging ; therapy ; Kidney Function Tests ; Male ; Middle Aged ; Pentetic Acid ; Radioisotope Renography ; methods ; Reproducibility of Results ; Retrospective Studies ; Sensitivity and Specificity ; Technetium ; Treatment Outcome ; Ureteral Obstruction ; diagnostic imaging ; therapy ; Urography ; methods

Objective: The complete staging and risk stratification of Papillary thyroid microcarcinoma (PTMC) is usually not done due to its theoretically low recurrence rates. This study aimed to determine the value of postoperative radioiodine diagnostic scan and SPECT/CT for the accurate staging and risk stratification in PTMC patients. Methodology: This study was a retrospective review of PTMC patients from January 2014 to May 2017 who underwent I-131 scans. All PTMC patients were initially staged by the 8th edition AJCC/TNM staging system and risk-stratified, based on clinical information, histopathology and stimulated thyroglobulin (sTg). After I-131 scan, staging and risk stratification were re-assessed. The proportion of patients who ended up with a higher stage and risk stratification were reported. Results and Conclusion Fifty-two patients were included. The overall upgrading of cancer stage was 7.7 %. The overall higher risk stratification was 19.2% with radioiodine-avid lymph node, lung, and bone metastases. Neck and paratracheal node metastases were found in 37.3% of the initial low-risk patients with sTg less than 5 ng/mL. Lung metastasis was found in the initial intermediate-risk patient. The I-131 scan helps to localize metastatic lesions and results in a higher stage in 50% of the initial high-risk patients. This study provides some evidence showing the value of postoperative radioiodine WBS for accurate staging and risk stratification in PTMC patients. Larger studies with analytical design should be further performed to prove its significant utility.