PREGNANCY LEADS TO 1. Physiologic dilatation

of the Collecting system , ureters .

2. Diminished peristaltic activity .

MICROSCOPICALLY :3. There is hypertrophy

of the ureteropelvic smooth muscle and hyperplasia of the connective tissue .

SPIRAL CT MRI

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Dr Arun Gupta Director imaging DepttDr Rakhee Gupta Dr Nitu Narula Dr Ritesh MahajanDr R K Gandhi

MR UROGRAM TO ASSESS GESTATIONAL HYDRONEPHROSIS

Dilatation of the collecting system / ureter far more affects the Rt side than the left side .Etiology : Possibly Multifactorial

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MR UROGRAM TO ASSESS GESTATIONAL HYDRONEPHROSIS

Dilatation of the ureters extends till the pelvic brim , distal to this point the calibre of the ureter is normal.

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MR UROGRAM TO ASSESS GESTATIONAL HYDRONEPHROSIS

Muscle relaxing affect of the progesterone like hormones and partial mechanical obstruction. Thickening of the muscle & connective tissue in the distal segment of the ureter .

Compression by the ovarian vein , iliac vessels ,pressure from the gravid uterus ( as it rotates to right with enlargement) .

Hypertrophy of the waldeyers sheath , a connective tissue envelope around the distal ureter might cause dilatation either by direct compresion or by preventing hormonally induced relaxation of the distal ureter .

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ETIOLOGYMULTIFACTORIAL

Brief ………………………….

• Dilatation usually resolves after pregnancy … Any persistent dilatation of the collecting system / ureter is sequel to UTI acquired during pregnancy .

• Dilated collecting system , ureter associated with sluggish peristalsis predisposes the patients to UTI .

• Dilatation of the PCS / URETERS appear as early as end of the first trimester and becomes maximal in third trimester.

• Ninety percent of the women are affected during pregnancy .

PHYSIOLOGICAL HYDRONEPHROSIS OF PREGNANCY MUST BE DISTINGUISHED FROM

OBSTRUCTIVE DISEASE. ULTRASOUND is the first step in a pregnant patient (does

not use ionizing radiation and is cheap). TVS is especially useful in visualizing distal ureteric calculi.

Absence of ureteral jet has a sensitivity of approx. 100% and specificity of nearly 91%. Scanning should be done with the patient in the contralateral decubitus position to improve ureteral jet detection (thus decreasing false-positive results from physiologic hydronephrosis).

COLOR DOPPLER : Intrarenal RI of ≥ 0.7 , that is also 0.4 higher than the value for the contralateral (normal) kidney has an overall accuracy of 99% for detecting obstructive hydronephrosis in pregnancy . Resolution of hydronephrosis after voiding

also differentiates physiologic hydronephrosis from obstructive

hydronephrosis.

IIMAGING

IMAGING IN

GESTATIONAL HYDRONEPHROSIS

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PET-CT Centre Sector 44-C Chandigarh

MR UROGRAPHY should be considered as a second-line test when use of US fails to establish a diagnosis and there are continued symptoms despite conservative management .

ADVANTAGES OF MR UROGRAPHY : MR urography can help in the detection of complications of

pyelonephritis. Perirenal edema and renal enlargement are seen in acute

obstruction and absent in physiologic hydronephrosis. High sensitivity has been reported for detection of urinary

tract dilatation and identification of the site of obstruction. In addition, physiologic dilatation demonstrates a

characteristic tapering due to extrinsic obstruction of the middle third of the ureter by the uterus .Physiologic renal and ureteral dilatation is more common on the right.

Drawbacks: Limited visualization of small calculi and relatively high cost .

IMAGING IN

GESTATIONAL HYDRONEPHROSIS

SPIRAL CT MRI

PET-CT Centre Sector 44-C Chandigarh

References………………..

Davidson AJ, Hartman DS, Choyke PL, Wagner BJ: Davidson’s Radiology of the kidney and genitourinaryTract. 3rd edition. Philadelphia: W.B.Saunders Company. 472-73

Woodfield CA, Lazarus E, Chen KC, Mayo-Smith WW. Abdominal pain in pregnancy: diagnoses and imaging unique to pregnancy—review. AJR 2010; 194[suppl]:WS14–WS30

 Shokeir AA, Mahran MR, Abdulmaaboud M. Renal colic in pregnant women: role of renal resistive index. Urology2000 ; 55:344 –347. CrossRef

Wachsberg RH. Unilateral absence of ureteral jets in the third trimester of pregnancy: pitfall in color Doppler US diagnosis of urinary obstruction.Radiology 1998;209 : 279–281. Cross Ref 

Spencer JA, Chahal R, Kelly A, et al. Evaluation of painful hydronephrosis in pregnancy: magnetic resonance urographic patterns in physiological dilatation versus calculus obstruction. J Urol 2004; 171:256 –260. Cross Ref

 Patel SJ, Reede DL, Katz DS et al. Imaging the Pregnant Patient for Nonobstetric Conditions: Algorithms and Radiation Dose Considerations. RadioGraphics 2007; 27: 1705-1722.