First name
Kassa
Last name
Darge

Title

Potential benefits of functional magnetic resonance urography (fMRU) over MAG3 renal scan in children with obstructive uropathy.

Year of Publication

2021

Date Published

2021 Jul 10

ISSN Number

1873-4898

Abstract

<p><strong>INTRODUCTION: </strong>Functional renal imaging, most commonly with MAG3 nuclear medicine renal scan, is recommended in the evaluation of children with urinary tract dilation (UTD) suspected of obstructive uropathy. Alternatively, renal function can be evaluated with functional Magnetic Resonance Urography (fMRU), which has superior anatomic detail. However, there are not enough data comparing both methods' equivalency. In this study, we compare the functional and obstruction parameters of fMRU and MAG3 in a pediatric cohort presenting with obstructive uropathy.</p>

<p><strong>STUDY DESIGN: </strong>This is an IRB-approved retrospective review of all children undergoing fMRU at a single, free-standing children's hospital between May 2008 and September 2017. Patients who also underwent a MAG3 renal scan within 6 months and who had no interval surgical intervention were included in the study. Bladder catheterization was performed prior to both imaging studies.</p>

<p><strong>RESULTS: </strong>735 children had 988 fMRU studies performed during the study period. 37 unique patients (13 girls and 24 boys) with median age of 6 months (range: 2 mo-19&nbsp;y) were included in the final sample. Median time interval between studies was 70 days (range 6-179 days). The majority of participants (26/37, 70.3%) presented with UTD P3 and had diagnosis of uretero-pelvic junction obstruction (UPJO) in 21/37. Differential renal function (DRF) was used to group 10 fMRU and 9 MAG3 patients as normal; 9 fMRU and 11 MAG3 as mild; 11 fMRU and 6 MAG3 as moderate; and 7 fMRU and 6 MAG3 as severe; Wilcoxon signed-rank test (p&nbsp;=&nbsp;0.5106). Results were similar for DRF among patients with and without duplex kidneys. In the analysis of obstruction, using reference standard T½ MAG3&nbsp;≥&nbsp;20&nbsp;min, a greater or equal than 6&nbsp;min renal transit time (RTT) from fMRU showed a specificity of 94%, a sensitivity of 62%, and an AUC of 0.827.</p>

<p><strong>DISCUSSION AND CONCLUSIONS: </strong>The differential renal function determined by MAG3 and fMRU in children was not statistically different, therefore we concluded that it was similar and potentially equivalent. Better correlation was shown in patients who had normal split kidney function. While the tests are clinically equivalent, the variability of DRF within each clinical category (i.e., normal, mild, moderate, severe) is not surprising, because MAG3 does not clearly differentiate the dilated collecting system from the functional parenchymal tissue, while fMRU does. Using MAG3 as the gold standard, fMRU was 94.74% specific and 5% more sensitive in detecting UPJO with a RTT of 6min vs. 8min.</p>

DOI

10.1016/j.jpurol.2021.07.005

Alternate Title

J Pediatr Urol

PMID

34426090

Title

Magnetic resonance elastography to quantify liver disease severity in autosomal recessive polycystic kidney disease.

Year of Publication

2020

Date Published

2020 Aug 05

ISSN Number

2366-0058

Abstract

<p><strong>OBJECTIVES: </strong>To evaluate whether liver and spleen magnetic resonance elastography (MRE) can measure the severity of congenital hepatic fibrosis (CHF) and portal hypertension (pHTN) in individuals with autosomal recessive polycystic kidney disease (ARPKD), and to examine correlations between liver MRE and ultrasound (US) elastography.</p>

<p><strong>METHODS: </strong>Cross-sectional study of nine individuals with ARPKD and 14 healthy controls. MRE was performed to measure mean liver and spleen stiffness (kPa); US elastography was performed to measure point shear wave speed (SWS) in both liver lobes. We compared: (1) MRE liver and spleen stiffness between controls vs. ARPKD; and (2) MRE liver stiffness between participants with ARPKD without vs. with pHTN, and examined correlations between MRE liver stiffness, spleen length, platelet counts, and US elastography SWS. Receiver operating characteristic (ROC) analysis was performed to examine diagnostic accuracy of liver MRE.</p>

<p><strong>RESULTS: </strong>Participants with ARPKD (median age 16.8 [IQR 13.3, 18.9] years) had higher median MRE liver stiffness than controls (median age 14.7 [IQR 9.7, 16.7&nbsp;years) (2.55 vs. 1.92&nbsp;kPa, p = 0.008), but MRE spleen stiffness did not differ. ARPKD participants with pHTN had higher median MRE liver stiffness than those without (3.60&nbsp;kPa vs 2.49&nbsp;kPa, p = 0.05). Liver MRE and US elastography measurements were strongly correlated. To distinguish ARPKD vs. control groups, liver MRE had 78% sensitivity and 93% specificity at a proposed cut-off of 2.48&nbsp;kPa [ROC area 0.83 (95% CI 0.63-1.00)].</p>

<p><strong>CONCLUSION: </strong>Liver MRE may be a useful quantitative method to measure the severity of CHF and pHTN in individuals with ARPKD.</p>

DOI

10.1007/s00261-020-02694-1

Alternate Title

Abdom Radiol (NY)

PMID

32757071

Title

Identification and characterization of calyceal diverticula with MR urography (MRU) in children.

Year of Publication

2020

Date Published

2020 Jun 23

ISSN Number

2366-0058

Abstract

<p><strong>PURPOSE: </strong>To determine the MRU imaging findings of calyceal diverticula in a large cohort of children and to compare the frequency of calyceal diverticula in our cohort with what has been previously reported.</p>

<p><strong>METHODS: </strong>This was a HIPAA-compliant, IRB-approved retrospective study of all patients with suspected CD based on their medical records. All patients in this study underwent MRU at our institution between 2010 and 2017. Two pediatric radiologists reviewed each MRU blinded to clinical information and other urologic imaging regarding the presence, size, location, and morphology of the cyst and presence/absence of contrast within it. The time when contrast first appeared within the cystic mass was recorded, and a χ test was used to determine significance on differences between the different characteristics of renal cysts and diverticula.</p>

<p><strong>RESULTS: </strong>Fifty children (29 girls and 21 boys; median age of 11.5&nbsp;years, IQR 7-16) with a total of 66 individual cystic masses were included. 21 (21/66, 31.8%) Cystic masses demonstrated contrast filling and were characterized as diverticula, resulting in a frequency of 26.6 cases per 1000 patients (21/787). The remaining 45 cystic masses (45/66, 68.1%) were cysts. The median diameter of CD was 2.5&nbsp;cm (IQR 1.5-3.7). Contrast was observed within the cystic mass on average at 4.6&nbsp;min (SD ± 2.4; range 1.5-13&nbsp;min). The agreement between both radiologists was 91% (k = 0.78). 6 Cysts and 18 CD were confirmed surgically, MRU demonstrated accurate diagnosis in 100% of those cases.</p>

<p><strong>CONCLUSION: </strong>Magnetic resonance urography is reliable in differentiating calyceal diverticula from renal cysts. On MRU, all diverticula were identified within 15&nbsp;min of contrast administration; hence longer delays in imaging are unnecessary.</p>

DOI

10.1007/s00261-020-02623-2

Alternate Title

Abdom Radiol (NY)

PMID

32577781

Title

Magnetic resonance elastography SE-EPI vs GRE sequences at 3T in a pediatric population with liver disease.

Year of Publication

2019

Number of Pages

894-902

Date Published

2019 03

ISSN Number

2366-0058

Abstract

<p><strong>PURPOSE: </strong>The goal of our study is to compare hepatic stiffness measures using gradient-recalled echo (GRE) versus spin-echo echo planar imaging (SE-EPI)-based MR Elastography (MRE) at 3T used to measure hepatic stiffness in a patients with suspected liver diseases.</p>

<p><strong>MATERIALS AND METHODS: </strong>This retrospective study included 52 patients with liver disease who underwent a 3T MRE exam including both an investigational SE-EPI-based technique and a product GRE-based technique. Regions of interest (ROI) were placed on the elastograms to measure elastography-derived liver stiffness as well as the area included within the ROIs. The mean liver stiffness values and area of ROIs were compared.</p>

<p><strong>RESULTS: </strong>The mean liver stiffness was 3.72 kilopascal (kPa) ± 1.29 using GRE MRE and 3.78&nbsp;kPa ± 1.13 using SE-EPI MRE. Measurement of liver stiffness showed excellent agreement between the two pulse sequences with a mean bias of - 0.1&nbsp;kPa (range - 1.8 to 1.7&nbsp;kPa) between sequences. The mean measurable ROI area was higher with SE-EPI (313.8&nbsp;cm ± 213.8) than with the GRE technique (208.6&nbsp;cm ± 114.8), and the difference was statistically significant (P &lt; 0.05).</p>

<p><strong>CONCLUSIONS: </strong>Our data shows excellent agreement of measured liver stiffness between GRE and SE-EPI-based sequences at 3T. Our results show the advantage of a SE-EPI MRE sequence in terms of image quality, ROI size and acquisition time with equivalent liver stiffness measurements as compared to GRE-MRE sequence.</p>

DOI

10.1007/s00261-018-1884-6

Alternate Title

Abdom Radiol (NY)

PMID

30600386

Title

Ultrasound Elastography to Quantify Liver Disease Severity in Autosomal Recessive Polycystic Kidney Disease.

Year of Publication

2019

Number of Pages

107-115.e5

Date Published

2019 06

ISSN Number

1097-6833

Abstract

<p><strong>OBJECTIVES: </strong>To evaluate the diagnostic accuracy of ultrasound elastography with acoustic radiation force impulse (ARFI) to detect congenital hepatic fibrosis and portal hypertension in children with autosomal recessive polycystic kidney disease (ARPKD).</p>

<p><strong>STUDY DESIGN: </strong>Cross-sectional study of 25 children with ARPKD and 24 healthy controls. Ultrasound ARFI elastography (Acuson S3000, Siemens Medical Solutions USA, Inc, Malvern, Pennsylvania) was performed to measure shear wave speed (SWS) in the right and left liver lobes and the spleen. Liver and spleen SWS were compared in controls vs ARPKD, and ARPKD without vs with portal hypertension. Linear correlations between liver and spleen SWS, spleen length, and platelet counts were analyzed. Receiver operating characteristic analysis was used to evaluate diagnostic accuracy of ultrasound ARFI elastography.</p>

<p><strong>RESULTS: </strong>Participants with ARPKD had significantly higher median liver and spleen SWS than controls. At a proposed SWS cut-off value of 1.56&nbsp;m/s, the left liver lobe had the highest sensitivity (92%) and specificity (96%) for distinguishing participants with ARPKD from controls (receiver operating characteristic area 0.92; 95% CI 0.82-1.00). Participants with ARPKD with portal hypertension (splenomegaly and low platelet counts) had significantly higher median liver and spleen stiffness than those without portal hypertension. The left liver lobe also had the highest sensitivity and specificity for distinguishing subjects with ARPKD with portal hypertension.</p>

<p><strong>CONCLUSIONS: </strong>Ultrasound ARFI elastography of the liver and spleen, particularly of the left liver lobe, is a useful&nbsp;noninvasive biomarker to detect and quantify liver fibrosis and portal hypertension in children with ARPKD.</p>

DOI

10.1016/j.jpeds.2019.01.055

Alternate Title

J. Pediatr.

PMID

30902421

Title

State-of-the-Art Renal Imaging in Children.

Year of Publication

2020

Date Published

2020 Jan 08

ISSN Number

1098-4275

Abstract

<p>Imaging modalities for diagnosing kidney and urinary tract disorders in children have developed rapidly over the last decade largely because of advancement of modern technology. General pediatricians and neonatologists are often the front line in detecting renal anomalies. There is a lack of knowledge of the applicability, indications, and nephrotoxic risks of novel renal imaging modalities. Here we describe the clinical impact of congenital anomalies of the kidneys and urinary tract and describe pediatric-specific renal imaging techniques by providing a practical guideline for the diagnosis of kidney and urinary tract disorders.</p>

DOI

10.1542/peds.2019-0829

Alternate Title

Pediatrics

PMID

31915193

Title

DTI of the kidney in children: comparison between normal kidneys and those with ureteropelvic junction (UPJ) obstruction.

Year of Publication

2019

Date Published

2019 Dec 16

ISSN Number

1352-8661

Abstract

<p><strong>OBJECTIVE: </strong>To compare renal diffusion tensor imaging (DTI) parameters in patients with or without ureteropelvic junction (UPJ) obstruction.</p>

<p><strong>METHODS: </strong>Patients that underwent functional MR urography (MRU) with renal DTI were retrospectively selected. Kidneys deemed normal on T2-weighted images and functional parameters were used as controls and compared to those kidneys with morphologic and functional findings of UPJ obstruction. DTI included a 20-direction DTI with b values of b = 0&nbsp;s/mm and b = 400&nbsp;s/mm. Diffusion Toolkit was used for analysis and segmentation. TrackVis was used to draw regions of interest (ROI) covering the entire volume of the renal parenchyma, excluding the collecting system. Fibers were reconstructed using a deterministic fiber tracking algorithm. Whole kidney ROI-based analysis was performed to obtain cortico-medullary measurements (FA, ADC and track length) for each kidney. T tests were performed to compare means and statistical significance was defined at p &lt; 0.05.</p>

<p><strong>RESULTS: </strong>118 normal kidneys from 102 patients (median age 7&nbsp;years, IQR 6-15&nbsp;years; 58 males and 44 females) were compared to 22 kidneys from 16 patients (median age 13&nbsp;years, IQR 3-15&nbsp;years; 9 males and 7 females) with UPJ obstruction. Mean FA values were significantly lower (0.31 ± 0.07; n = 22) in kidneys with UPJ obstruction than normal kidneys (0.40 ± 0.08; n = 118) (p &lt; 0.001). ADC was marginally significantly increased (p = 0.01) and track length was not significantly different (p = 0.24).</p>

<p><strong>CONCLUSION: </strong>Our results suggest that DTI-derived metrics including FA and ADC are potential biomarkers to differentiate kidneys with UPJ obstruction and assess renal parenchymal damage.</p>

DOI

10.1007/s10334-019-00812-9

Alternate Title

MAGMA

PMID

31845301

Title

Morphologic and functional evaluation of duplicated renal collecting systems with MR urography: A descriptive analysis.

Year of Publication

2019

Number of Pages

69-76

Date Published

2019 May 15

ISSN Number

1873-4499

Abstract

<p><strong>PURPOSE: </strong>To describe the morphology and function of duplicated collecting systems in pediatric patients undergoing functional MR urography (fMRU).</p>

<p><strong>METHODS: </strong>This is a HIPAA compliant IRB approved retrospective study of all patients with duplicated renal collecting systems undergoing fMRU at our institution between 2010 and 2017. Two pediatric radiologists evaluated the studies to determine the presence, morphology and function of duplicated collecting systems using both T2-weighted and dynamic post-contrast fat saturated T1-weighted images. Assessed morphologic features included pelvic and calyceal dilation, partial or complete ureteral duplication, ureteral dilation, ectopic ureteral insertion and ureteroceles. Functional analysis was carried out per moiety.</p>

<p><strong>RESULTS: </strong>A total of 86 examinations (63 girls; 23 boys), median age 2.6 years (Standard Deviation 6.4 years, interquartile range: 0.4-10.3 years) and 107 kidneys (39 right; 30 left and 19 bilateral), which yielded 214 evaluable moieties, were included in the final sample. One hundred and sixty-three (76.1%) of the moieties had normal morphological features and normal functional results (average calyceal transit time and renal transit time of 2 min 28 s and 3 min 16 s, respectively). The remaining 51 moieties (23.8%) were hypoplastic or dysplastic. Seventy-seven (35.9%) had pelvic and calyceal dilation. Slightly more than half of the kidneys had complete ureteral duplication (60/107; 56%); 50 (50/107, 46.7%) had ectopic ureters (23 intra- and 27 extravesical) and 9 (9/107, 8.4%) had ureteroceles.</p>

<p><strong>CONCLUSION: </strong>fMRU provides comprehensive information regarding the morphology and function of duplicated renal collecting systems in children. In particular, fMRU is useful for assessing barely or non-functioning renal poles and ectopic ureters.</p>

DOI

10.1016/j.clinimag.2019.05.004

Alternate Title

Clin Imaging

PMID

31136881

Title

Diffusion tensor imaging of the kidney in healthy controls and in children and young adults with autosomal recessive polycystic kidney disease.

Year of Publication

2019

Date Published

2019 Feb 19

ISSN Number

2366-0058

Abstract

<p><strong>OBJECTIVE: </strong>To compare diffusion tensor imaging (DTI) of the kidneys and its derived parameters in children with autosomal recessive polycystic kidney disease (ARPKD) versus healthy controls.</p>

<p><strong>METHODS: </strong>In a prospective IRB-approved study, we evaluated the use of DTI to compare kidney parenchyma FA values in healthy controls (age-matched children with no history of renal disease) versus patients with ARPKD. A 20-direction DTI with b-values of b = 0&nbsp;s/mm and b = 400&nbsp;s/mm was used to acquire data in coronal direction using a fat-suppressed spin-echo echo-planar sequence. Diffusion Toolkit and TrackVis were used for analysis and segmentation. TrackVis was used to draw regions of interest (ROIs) covering the entire volume of the renal parenchyma, excluding the collecting system. Fibers were reconstructed using a deterministic fiber tracking algorithm. The FA values based on the ROI data, mean length, and volume of the tracks based on the fiber tracking data were recorded.</p>

<p><strong>RESULTS: </strong>Eight healthy controls (mean age = 12.9&nbsp;years ± 4.0; 1/8 males) and six ARPKD participants (mean age = 13.8&nbsp;years ± 8.5; 5/6 males) were included in the study. Compared to healthy controls, patients with ARPKD had significantly lower FA values (0.33 ± 0.03 vs. 0.25 ± 0.02, p = 0.002) and mean track length (16.73 ± 3.43 vs. 11.61 ± 1.29&nbsp;mm, p = 0.005).</p>

<p><strong>CONCLUSION: </strong>DTI of the kidneys shows significantly lower FA values and mean track length in children and young adults with ARPKD compared to normal subjects. DTI of the kidney offers a novel approach for characterizing renal disease based on changes in diffusion anisotropy and kidney structure.</p>

DOI

10.1007/s00261-019-01933-4

Alternate Title

Abdom Radiol (NY)

PMID

30783727

Title

Role of magnetic resonance urography in pediatric renal fusion anomalies.

Year of Publication

2017

Date Published

2017 Aug 24

ISSN Number

1432-1998

Abstract

<p>Renal fusion is on a spectrum of congenital abnormalities that occur due to disruption of the migration process of the embryonic kidneys from the pelvis to the retroperitoneal renal fossae. Clinically, renal fusion anomalies are often found incidentally and associated with increased risk for complications, such as urinary tract obstruction, infection and urolithiasis. These anomalies are most commonly imaged using ultrasound for anatomical definition and less frequently using renal scintigraphy to quantify differential renal function and assess urinary tract drainage. Functional magnetic resonance urography (fMRU) is an advanced imaging technique that combines the excellent soft-tissue contrast of conventional magnetic resonance (MR) images with the quantitative assessment based on contrast medium uptake and excretion kinetics to provide information on renal function and drainage. fMRU has been shown to be clinically useful in evaluating a number of urological conditions. A highly sensitive and radiation-free imaging modality, fMRU can provide detailed morphological and functional information that can facilitate conservative and/or surgical management of children with renal fusion anomalies. This paper reviews the embryological basis of the different types of renal fusion anomalies, their imaging appearances at fMRU, complications associated with fusion anomalies, and the important role of fMRU in diagnosing and managing children with these anomalies.</p>

DOI

10.1007/s00247-017-3927-5

Alternate Title

Pediatr Radiol

PMID

28840306

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