Dilatation of the collecting system during pregnancy: physiologic vs obstructive dilatation

Grenier, N.; Pariente, Jean-Louis; Trillaud, Hervé; Soussotte, Catherine; Douws, C.

doi:10.1007/s003300050043

Cited by 78 publications

(25 citation statements)

References 39 publications

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“…Current study MRU with T1WI, T2WI 83% Table 10 MRU performed in a pregnant woman 12,19,20 in the second trimester showed compression of mid ureter with tapering at the pelvic brim. Ureter below this level of compression is relatively collapsed.…”

Section: Sl Nomentioning

confidence: 86%

Non-Contrast Magnetic Resonance Urography- A Prospective Study

S¹,

M²,

Jayalatha³

2017

jemds

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BACKGROUNDThe key element, iodine set the stage for all future developments in contrast material for radiographic imaging. From this stage, extensive development of the quality of contrast medium has grown immensely to the present stage of non-ionic contrast media which are considered to be safe. The aims of this study are-1. To study the efficacy of static MR urography in comparison with conventional urography. 2. To study the levels and causes of obstruction of urinary tract by MR urography and compare them with other investigation procedures. MATERIALS AND METHODS120 patients who presented with clinical symptoms and signs pertaining to renal diseases and were positive on conventional MRI from Department of Radiodiagnosis, Osmania Medical College/ Hospital, Hyderabad, were selected for this study. This is an Institution-based cross-sectional study. MRU was performed on SIGNA HD 1.5 Tesla MRI, GE Healthcare (Milwaukee, USA). A body coil and commercially available software were used. SIGNA HD 1.5T is a diagnostic imaging device, which generates and displays transverse, sagittal, coronal and paraxial whole body images. Before performing MR urography, 3-plane localiser obtained in three planes was used to confirm optimum patient positioning; axial and coronal T2 weighted single shot FSE sequences of KUB region were taken, (TR 1615 msec, TE 88 msec, FOV 38 x 38, Matrix 256 x 256, NEX 0.56, TA 49 sec). The imaging method was based on the physical principle of magnetic resonance (MR). During the measurement, the patient was placed on the strong homogeneous magnetic field. The hydrogen nuclei (protons) distributed throughout the entire body tissue generate signals when stimulated by an RF field. These signals were processed into images by a computer. RESULTSIn our study, 3D respiratory triggered sequences 3D FR FSE (Fast Recovery Fast Spin Echo) sequence was used. It provides high signal intensity of fluid even with short repetition time. After signal decay at end of echo train, a negative 90 degree pulse align spins with long T2 from transverse plane to longitudinal plane leading to a much faster recovery of tissues with long T2 time to equilibrium and thus better contrast between tissues with long and short T2. A frequency-selective fat-saturation pulse was used to reduce signal from retroperitoneal fat. During a period of 3 years, a total of 120 patients formed the study group. This included 52 females (43%) and 68 males (57%). Most patients in this study group belonged to the 3 rd decade. Commonest complaint in this study was pain followed by dysuria. MR Urography images were of relatively good quality. Distension of urinary bladder aided in better visualisation of upper urinary tract. We had considerable difficulty in removal of overlying bowel from images of few patients. Renal sizes could be easily measured, renal contours were normal, no masses and other parenchymal abnormalities were seen. Calyceal, forniceal and infundibular anatomy was not seen with the same detail as with an IVU. Anatomy of retrop...

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Section: Sl Nomentioning

confidence: 86%

Non-Contrast Magnetic Resonance Urography- A Prospective Study

S¹,

M²,

Jayalatha³

2017

jemds

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“…During the third trimester of pregnancy physiologic dilatation of the collecting system is found in up to 90 % of pregnant women [25,26]; thus, differentiation between physiologic dilatation and obstruction, e.g., due to passing kidney stone, is challenging. In this setting, as physiologic dilatation during pregnancy does not alter the RI, evaluation of intrarenal Doppler spectra and assessment of ureteral jets might be helpful diagnostic tools without any ionizing radiation [26].…”

Section: Hydronephrosis In Pregnancymentioning

confidence: 99%

Ultrasound of the kidney: obstruction and medical diseases

2001

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Ultrasound has emerged as the primary imaging modality in conditions where either renal obstruction or renal medical disease is suspected on the basis of clinical and laboratory findings. In urinary tract obstruction, pathophysiologic changes affecting the pressure in the collecting system and kidney perfusion are well understood and form the basis for the correct interpretation of real-time US and color Doppler duplex sonography (CDDS). Ultrasound is very sensitive for the detection of collecting system dilatation ("hydronephrosis"); however, obstruction is not synonymous with dilatation, as either obstructive or nonobstructive dilatation may be present. To differentiate these conditions, CDDS with measurement of the resistive index (RI) in the intrarenal arteries is extremely helpful, as obstruction (except in the peracute stage) leads to intrarenal vasoconstriction with a consecutive increase of the RI above the upper limit of 0.7, whereas nonobstructive dilatation does not. Diuretic challenge to the kidney may further enhance these differences in RI between obstruction and dilatation. Based on these findings, the present value of US and CDDS in the assessment of the patient with flank pain or renal colic is suggested, especially with respect to promising results for spiral CT and based on cost analysis. In renal medical disease, distinguishing different pathologic conditions using gray-scale US and CDDS (RI) criteria is still very difficult. Nevertheless, US is the fist-line imaging modality in the patient with renal insufficiency.

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“…Magnetic resonance urography is gaining popularity as an alternative technique of urinary tract imaging in a wide range of clinical settings [1,2,3,4,5,6,7,8,9,10,11,12,13,14]. The introduction of heavily T2-weighted very fast-spin-echo sequences, such as rapid acquisition with relaxation enhancement (RARE), half-Fourier acquisition single-shot turbo spin echo (HASTE) and similar modifications, allowed high-quality MRU and reduced breathing-related artefacts [1,2,3,4,5].…”

Section: Introductionmentioning

confidence: 99%

Filling defect artefacts in magnetic resonance urography

2004

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The aim of this study was to determine the prevalence of filling defect artefacts (FDA) in magnetic resonance urography (MRU). Retrospectively, we assessed MRU examinations of 45 patients with neurogenic bladder dysfunction (21 men, 24 women; mean age 35 years, age range 18-71 years). The MRU was performed 30 min after intramuscular injection of 20 mg frusemide using heavily T2-weighted fast-spin-echo techniques [axial, thick coronal slab, coronal maximum intensity projection (MIP) images] with fat saturation. The images were reviewed by two observers to determine the presence of filling defects and dilatation of pelvicalyceal system and ureters. The filling defects were classified into central, eccentric and complete. Clinical course and plain films were reviewed to determine significance of the detected filling defects. True filling defects were observed in 5 patients (11%) and all due to stones seen on the plain radiograph of the abdomen. Filling defects artefacts (FDAs) were seen in 23 patients (51%; 17 pelvicalyceal system, 17 upper third of ureters, 7 mid ureters and 1 distal ureter). No stones were seen on the plain radiograph of these patients and they had a favourable clinical course for over 24 months. The true filling defects were large in size, eccentric in position and seen in more than one sequence of the MRU examination (axial, n=5; slab, n=5; and MIP, n=4). Four (80%) of the patients with true defects and 21 (91%) of those with FDAs had dilatation of the pelvicalyceal system and ureters. The FDAs were small in size, centrally placed (74%) and always seen in axial images, rarely in slab images (2 cases) and not seen in MIP images. Artefactual filling defects can be seen in MRU examinations. The cause of the FDAs is not fully explained and could be secondary to turbulent and fast flow of the urine. Some of the FDAs seen in the calyces could be due to the tips of the papillae. Awareness of such defects obviates misinterpretation and prevents unnecessary further investigations or interventions.

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Dilatation of the collecting system during pregnancy: physiologic vs obstructive dilatation

Cited by 78 publications

References 39 publications

Non-Contrast Magnetic Resonance Urography- A Prospective Study

Non-Contrast Magnetic Resonance Urography- A Prospective Study

Ultrasound of the kidney: obstruction and medical diseases

Filling defect artefacts in magnetic resonance urography

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