Restricted diffusion MRI as a functional biomarker for the assessment of acute calcular upper urinary tract obstruction: initial experience

Background Acute renal obstruction due to stone is a prevalent scenario. The diffusion-weighted magnetic resonance imaging (DWI) of the kidneys provides a noninvasive information on renal function. Our objective is to prospectively assess the potential role of DWI to predict the signal changes of a kidney with acute calcular obstruction. Results Chi-square and Fissure exact tests were used to assess the association of diffusion signal changes among patients and control groups. Cohen's Kappa test was run to determine the degree of agreement between the two radiologists. An independent sample t-test was performed to assess the significant difference among ADC values between the two groups. Restricted signals of the obstructed kidneys showed a statistically significant difference when compared with contralateral unobstructed kidney and control group with p value (0.001) and (0.01), respectively. Furthermore, there is a moderate agreement between the two radiologists K = 0.7, p = 0. 001. There is no statistically significant difference in ADC values when comparing the obstructed kidney and the contralateral unobstructed kidney of the patient group or with the control group p value (0.06) and (0.05), respectively. Conclusion Restricted signals of the obstructed kidney by DWI may be a helpful tool in diagnosing acute unilateral renal obstruction and can affect its management; however, it needs further validation by more studies.

Renal function estimation done by contrast enhanced computed tomography volume percentage: a better cost-effective alternate for renogram values

Background: For optimal management of obstructive uropathy the function of each renoureteral unit needs to be assessed precisely. Usage of nuclear scan for estimation of split renal function has been standard technique till now. Renal parenchymal volume percentage, which is calculated through multislice CT, used as a surrogate marker of split renal function. The aim of the study was to correlate the renal volume percentage calculated from contrast enhanced computed tomography (CECT) of kidney, ureter and bladder (KUB) with split renal function estimated by the gold standard 99mTc-DTPA (diethylene triamine pentaacetic acid) among obstructive uropathy patients.Methods: Patients who have been diagnosed as chronic unilateral renal obstruction and were requiring 99mTC-DTPA nuclear scan for functional assessment of kidneys were included as our study subjects. A total of 46 patients were taken as our study sample and for all these patients CECT KUB was done and the reports were collected and the renal volume percentage was obtained through those images. Correlation was made between the measurements made by nuclear scan and CECT images in unilateral renal obstruction patients.Results: A positive linear correlation was obtained between DTPA nuclear scan and CECT images in the detection of renal volume/renal function with r value 0.904 (p<0.05) in obstructive renal units and similarly among non-obstructive renal units the r value was 0.889 (p<0.001).Conclusions: Though 99mTc-DTPA renal scan is a safest choice by considering its less radiation exposure and no contrast requirement still cost and its universal availability make us to consider CECT as a better alternative.

Emergency versus elective ureteroscopy for the management of ureteral stones

Objective: To assess the safety and efficacy of emergency ureteroscopy (URS) compared with elective URS. Methods: We conducted a retrospective analysis of patients who underwent URS for isolated ureteral stones in a single center from October 2001 to February 2014. Our patient cohort was divided into two groups: an emergency URS group (Group A), which consisted of patients who underwent URS within the first 24 h of admission, and an elective or planned URS group (Group B). The URS success rate was defined as being the incidence of successful stone fragmentation and whether there was resolution of renal obstruction. Results: A total of 2957 patients’ medical records were available for analysis. Of these, 704 (21%) comprised of emergency cases and the remaining 2253 (79%) were elective cases. Patients in Group A were younger, had a smaller BMIs, and had smaller stone sizes ( p < 0.001). The URS success rate was found to be 97% in Group A and 96% in Group B ( p = 0.35). Intraoperative or postoperative complication rates were not found to vary significantly between the groups (8% vs 7%, respectively, p = 0.50). The incidence of ureteral stenting was nearly twice as high if URS was performed during night hours (85% vs 45%, p < 0.001). However, ureteral stenting was more prevalent in Group B compared to Group A patients (57% vs 25%, p < 0.001), possibly as a result of the number of pre-stented patients (73%). Conclusions: Emergency URS is an effective and safe option for patients with renal colic. Younger patients without pre-existing obesity and with stone sizes up to 8 mm located in the distal ureter might be a better match for emergency URS.

Comparison of Resistivity Index of Segmental Arteries Between Normal and Obstructed Kidneys in Ureterolithiasis with Doppler Ultrasonography

These days, the most common problem that the urologists face is Urolithiasis and renal colic is the most highlighted one. Renal obstruction due to urolithiasis is the most frequent cause. This disease is widespread in our country and 12% of the Pakistani population has urolithiasis.

Neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker of renal injury in patients with ureteric stones: a pilot study

Objective: The role of neutrophil gelatinase-associated lipocalin in renal obstruction remains unclear. The aim of this study is to assess neutrophil gelatinase-associated lipocalin kinetics and its potential role as a biomarker of renal damage in acute ureteric colic. Methods: Thirty-six patients with acute ureteric colic were prospectively recruited and compared with two control groups. Blood and urine samples for plasma neutrophil gelatinase-associated lipocalin and urinary neutrophil gelatinase-associated lipocalin levels were obtained at various time points. Results: There were significantly higher levels of urinary neutrophil gelatinase-associated lipocalin and the urinary neutrophil gelatinase-associated lipocalin/creatinine ratio at presentation when comparing patients with acute ureteric colic to healthy controls ( P=0.002 and P=0.004, respectively). In patients with acute ureteric colic managed with surgical intervention ( n=27) there was a significant reduction in plasma neutrophil gelatinase-associated lipocalin ( P=0.001) and an increase in the urinary neutrophil gelatinase-associated lipocalin/creatinine ratio 6 hours postoperatively ( P=0.03). Eight of nine patients managed conservatively for acute ureteric obstruction had spontaneous stone passage at follow-up (median 26 days) with a significant reduction in the urinary neutrophil gelatinase-associated lipocalin/creatinine ratio ( P=0.03). Conclusion: The observation of a reduction in plasma neutrophil gelatinase-associated lipocalin and urinary neutrophil gelatinase-associated lipocalin levels following relief of renal obstruction due to ureteric stones suggests the potential role of neutrophil gelatinase-associated lipocalin as a biomarker in this scenario and in the follow-up setting as a potential marker of relief of obstruction. Level of evidence: 3b

A correlation study of the effectiveness of renal scintigraphy and sonography in the detection and evaluation of renal disorders

Background: This retrospective study was undertaken to assess correlation between renal scintigraphy employing technetium Tc-99m chelated with radiopharmaceutical drug Diethylenetriamine Penta Acetic Acid (DTPA) and renal ultrasonography morphological findings. Methods: For this purpose, ninety six patients imaging data was statistically analyzed including 43 females and 53 males. All the patients were subjected to renal scintigraphy while 68 patients underwent renal ultrasonography. Renal U/S reported anatomical renal anomaly in 94.1% patients versus 85.4% detected by scintigraphy. There were 41 patients out of 68 diagnosed with hydronephrosis and 21 of them were suffering with mild hydronephrosis as suggested by U/S imaging. Results: Renal scintigraphy of 41 hydronephrotic patients validated that 19 patients having non-obstructive bilateral pelvic dilation while remaining 22 with mild to severe obstruction. Ultrasonography diagnosed 4 patients with renal obstruction. Conversely, renal scintigraphy validated 2 of them with renal obstruction on the basis of renal function. In total, 19 out 96 patients were reported with renal obstruction through scintigraphy and validated obstruction in 1 of the 3 patients who were diagnosed with abnormal postvoid residual volume through U/S. Conclusion: Renal scintigraphy is not significant in diagnosing kidney disease; rather this is a vibrant imaging tool providing supplementary data on the basis of renal function. Effectively targeted intervention regime can be achieved by correlating renal scintigraphy and renal ultrasonography results to minimize renal disease incidence.

Drug-induced renal disorder-A Mini Review

Drug-induced kidney disorder/disease (DKID) is an origin of kidney disease followed by acute renal failure. Drug-induced renal toxicity is more common in infants and young children in certain clinical circumstances where underlying renal dysfunction and cardiovascular diseases. Sometimes, administered drugs may cause acute renal injury, intra-renal obstruction, interstitial nephritis, nephrotic syndrome, and acid-base and fluid electrolytes disorders in patients. Certain drugs may cause alterations in intra-glomerular hemodynamics, inflammatory changes in renal tubular cells, leading to acute kidney injury (AKI), interstitial tubule disease, and renal scarring. Common risk factors include; pre-existing renal dysfunction, volume-depleted state, old age, and use of nephrotoxic drugs. Therefore, the prevention from the disease includes the knowledge about the nephrotoxicity, assessing considering the patient-related, kidney-related, and drug-related factors while prescribing medicines, using of alternative drugs, which are non-nephrotoxic, assessing the baseline of renal function before starting the treatment, monitor the renal function during the treatment and avoid the nephrotoxic drug combinations and withdrawing the offending drugs due to toxicity. The ADRs of the prescribed/ administered are identified at the earliest to prevent the development of the last-stage renal disorder. This review discusses the risk factors associated with drug-induced renal disease, estimation of renal function, mechanism of drug-induced nephrotoxicity, and certain drugs that cause nephrotoxicity.