29THE UROGENITAL TRACT: ANATOMY

AND INVESTIGATIONS

DAVID SUTTON

DAVID SUTTON PICTURES

DR. Muhammad Bin Zulfiqar PGR-FCPS III SIMS/SHL

• Fig. 29.1 Structure of the kidney. 1, Cortex; 2, compound calyx 3, minor calyx; 4, medullary pyramid; 5, papilla; 6, renal sinus; 7, renal pelvis; 8, infundibulum of major calyx; 9, ureter.

• Fig. 29.3 Anterior relations of (A) the right kidney, and (B) the left kidney. 1, Hepatic flexure; 2, small intestine; 3, right adrenal gland; 4, liver; 5, duodenum; 6, left adrenal gland; 7, spleen; 8, stomach; 9, pancreas; 10, splenic flexure.

• Fig. 29.5 The relationships of the prostate.

• Fig. 29.6 The KUB. (A) Full length and (B) cross kidney films from a KUB examination. Several phleboliths are seen in the pelvis. They are characteristically smooth small rounded calcific areas with a tiny central radiolucency.

• Fig. 29.7 Postcontrast IVU films. (A) Immediate, (B) 5 min, (C) 15 min film with compression producing calyceal distension; (D) full length release; (E) full length postmicturition. The phleboliths noted on the plain films (Fig. 29.6A) are nicely shown to lie outside the urinary tract.

• Fig. 29.7 Postcontrast IVU films. (A) Immediate, (B) 5 min, (C) 15 min film with compression producing calyceal distension; (D) full length release; (E) full length postmicturition. The phleboliths noted on the plain films (Fig. 29.6A) are nicely shown to lie outside the urinary tract.

• Fig. 29.7 Postcontrast IVU films. (A) Immediate, (B) 5 min, (C) 15 min film with compression producing calyceal distension; (D) full length release; (E) full length postmicturition. The phleboliths noted on the plain films (Fig. 29.6A) are nicely shown to lie outside the urinary tract.

• Fig. 29.8 Normal renal ultrasound; note the relatively hypoechoic pyramids and markedly hyperechoic fat containing sinus (centrally) compared to the cortex.

• Fig. 29.9 Normal bladder ultrasound; note the thin smooth wall and the shape approximating to a rounded-off square in the transverse view (A) and a rounded-off triangle in the sagittal view (B).

• Fig. 29.10 Scrotal ultrasound. (A) Longitudinal image showing the intermediate slightly speckled appearance of the normal testicle. The thin echogenic line represents the mediastinum of the testicle. (B) Longitudinal view showing a prominent vascular channel (linear echopoor structure)-normal variant. (C) Longitudinal view showing the body of the epididymis as a thin echo-poor line posterior to the testicle. Transverse view of the testicle through the mid (D) and upper (E) parts, the latter showing the bead of the epididymis as a small area of soft tissue adjacent to the upper pole of the testicle.

• Fig. 29.10 Scrotal ultrasound. (A) Longitudinal image showing the intermediate slightly speckled appearance of the normal testicle. The thin echogenic line represents the mediastinum of the testicle. (B) Longitudinal view showing a prominent vascular channel (linear echopoor structure)-normal variant. (C) Longitudinal view showing the body of the epididymis as a thin echo-poor line posterior to the testicle. Transverse view of the testicle through the mid (D) and upper (E) parts, the latter showing the bead of the epididymis as a small area of soft tissue adjacent to the upper pole of the testicle.

• Fig. 29.10 Scrotal ultrasound. (A) Longitudinal image showing the intermediate slightly speckled appearance of the normal testicle. The thin echogenic line represents the mediastinum of the testicle. (B) Longitudinal view showing a prominent vascular channel (linear echopoor structure)-normal variant. (C) Longitudinal view showing the body of the epididymis as a thin echo-poor line posterior to the testicle. Transverse view of the testicle through the mid (D) and upper (E) parts, the latter showing the bead of the epididymis as a small area of soft tissue adjacent to the upper pole of the testicle.

• Fig. 29.11 Transrectal ultrasound of the prostate. (A-C) Young adult prostate. (A) Transverse section. There is a little calcification appearing as speckled echogenicity in the periurethral area, presumed to be related to previous prostatitis and urethritis. The prostate at this age shows poor zonal anatomy. (B) Transverse view of the normal paired echo-poor seminal vesicles. (C) Longitudinal view showing the subjacent puborectalis sling as a laminated, relatively echo-poor structure. (D, E) Transverse and longitudinal views of the prostate around middle to old age. The zonal anatomy is clearly seen with a relatively hyperechoic peripheral gland compared to the hypoechoic central gland.

• Fig. 29.11 Transrectal ultrasound of the prostate. (A-C) Young adult prostate. (A) Transverse section. There is a little calcification appearing as speckled echogenicity in the periurethral area, presumed to be related to previous prostatitis and urethritis. The prostate at this age shows poor zonal anatomy. (B) Transverse view of the normal paired echo-poor seminal vesicles. (C) Longitudinal view showing the subjacent puborectalis sling as a laminated, relatively echo-poor structure. (D, E) Transverse and longitudinal views of the prostate around middle to old age. The zonal anatomy is clearly seen with a relatively hyperechoic peripheral gland compared to the hypoechoic central gland.

• Fig. 29.12 Retrograde pyelogram demonstrating the pelvicalyceal system and ureter down to the vesicoureteric junction.

• Fig. 29.13 Retrograde pyelogram with pyelosinus extravasation due to overdistension of the collecting system.

• Fig. 29.14 Normal loopogram (conduitogram). Contrast outlines the ileal loop (which still demonstrates the typical small-bowel mucosal pattern) and freely refluxes into both ureters.

• Fig. 29.15 Normal stentogram demonstrating intact anastamosis between the ureters and the afferent loop of small bowel leading to the reconstructed neobladder.

• Fig. 29.17 Normal female micturating cystourethrogram showing the typical short open-necked female urethra.

• Fig. 29.16 Post prostatectomy cystogram. Supine (A), oblique (B) and lateral (C) views demonstrate a substantial extravasation arising from the right posterolateral aspect of the vesicourethral anastamosis.

• Fig. 29.16 Post prostatectomy cystogram. Supine (A), oblique (B) and lateral (C) views demonstrate a substantial extravasation arising from the right posterolateral aspect of the vesicourethral anastamosis.

• Fig. 29.18 Descending urethrogram in a male. The entire length of the urethra is demonstrated as the bladder empties. A post-operative urethrorectal fistula is present with contrast tracking posteriorly from the prostatic beds.

• Fig. 29.19 The normal male ascending urethrogram usually shows contrast flowing retrogradely as far as the junction of the bulbar and membranous urethra (A). Sometimes contrast will flow into the bladder and demonstrate the prostatic urethra (B). Note the smooth filling defect of the verumontanum within the prostatic urethra.

• Fig. 29.20 Ascending urethrogram. A vigorous infusion of 150 strength contrast has been performed. The external sphincter has not relaxed (as is usually the case) and the anterior urethra is therefore overdistended with contrast extravasating and entering the corpora cavernosa.

• Fig. 29.21 Antegrade pyelography. The dilated pelvicalyceal system has been cannulated with a 22 gauge needle and opacified with 1 50 strength contrast (A). The ureter is dilated, shows marked medial displacement distally and tapers to a complete occlusion (B).

• Fig. 29.22 Nephrostomy procedure using fluoroscopy and dual puncture technique. Having opacified the system through a fine-gauge needle a second puncture is made with a sheathed needle (A). A guide-wire is advanced through this into the pelvicalyceal system (and ideally for stability into the ureter) (B). The fine needle is removed and the sheathed needle exchanged for a dilator over the wire (C). The calibre of the dilator depends on the nephrostomy drain to be positioned and often comes as part of a nephrostomy set. For an 8F drain a dilator of 8 or 9F is usually employed. The dilator is exchanged for the drain, which is positioned, coiled up, in the renal pelvis (D).

• Fig. 29.22 Nephrostomy procedure using fluoroscopy and dual puncture technique. Having opacified the system through a fine-gauge needle a second puncture is made with a sheathed needle (A). A guide-wire is advanced through this into the pelvicalyceal system (and ideally for stability into the ureter) (B). The fine needle is removed and the sheathed needle exchanged for a dilator over the wire (C). The calibre of the dilator depends on the nephrostomy drain to be positioned and often comes as part of a nephrostomy set. For an 8F drain a dilator of 8 or 9F is usually employed. The dilator is exchanged for the drain, which is positioned, coiled up, in the renal pelvis (D).

• Fig. 29.23 Antegrade stent positioning. A guide-wire has been manipulated down the right ureter to the level of the obstruction (A). Note the distal end of a previously postioned left-sided stent is visible within the bladder. The guide-wire is advanced across the obstruction into the bladder. Following a dilatation step with a long 9F dilator the stent has been advanced along the wire so its distal end lies within the bladder (B). Once the wire is removed the distal end of the stent will adopt a pigtail configuration within the bladder. The upper end will behave similarly within the renal pelvis, provided care has been taken to ensure the upper end has been advanced sufficiently and does not lie within renal parenchyma.

• Fig. 29.24 Percutaneous nephrolithotomy. A faintly opacified staghorn calculus is present (A). A retrograde catheter is in position. After the system is opacified and dilated via the retrograde catheter a sheathed needle is used to cannulate one of the calyces (B). A guide-wire is advanced through the sheath into the calyx and manipulated into the renal pelvis adjacent to the calculus (C). An initial dilatation step is performed with an 8F dilator over the wire (D). A high-pressure balloon is positioned with its distal end in the collecting system. As it is inflated a waist at the level of the renal capsule is often the last part to dilate (E). Following inflation an Amplatz sheath is positioned over the balloon (F-example from a second patient). The balloon is deflated and removed, allowing the urologist access to the calculus. After the procedure fluoroscopy demonstrates adequate clearance of the stone (G).

• Fig. 29.24 Percutaneous nephrolithotomy. A faintly opacified staghorn calculus is present (A). A retrograde catheter is in position. After the system is opacified and dilated via the retrograde catheter a sheathed needle is used to cannulate one of the calyces (B). A guide-wire is advanced through the sheath into the calyx and manipulated into the renal pelvis adjacent to the calculus (C). An initial dilatation step is performed with an 8F dilator over the wire (D). A high-pressure balloon is positioned with its distal end in the collecting system. As it is inflated a waist at the level of the renal capsule is often the last part to dilate (E). Following inflation an Amplatz sheath is positioned over the balloon (F-example from a second patient). The balloon is deflated and removed, allowing the urologist access to the calculus. After the procedure fluoroscopy demonstrates adequate clearance of the stone (G).

• Fig. 29.24 Percutaneous nephrolithotomy. A faintly opacified staghorn calculus is present (A). A retrograde catheter is in position. After the system is opacified and dilated via the retrograde catheter a sheathed needle is used to cannulate one of the calyces (B). A guide-wire is advanced through the sheath into the calyx and manipulated into the renal pelvis adjacent to the calculus (C). An initial dilatation step is performed with an 8F dilator over the wire (D). A high-pressure balloon is positioned with its distal end in the collecting system. As it is inflated a waist at the level of the renal capsule is often the last part to dilate (E). Following inflation an Amplatz sheath is positioned over the balloon (F-example from a second patient). The balloon is deflated and removed, allowing the urologist access to the calculus. After the procedure fluoroscopy demonstrates adequate clearance of the stone (G).

• Fig. 29.24 Percutaneous nephrolithotomy. A faintly opacified staghorn calculus is present (A). A retrograde catheter is in position. After the system is opacified and dilated via the retrograde catheter a sheathed needle is used to cannulate one of the calyces (B). A guide-wire is advanced through the sheath into the calyx and manipulated into the renal pelvis adjacent to the calculus (C). An initial dilatation step is performed with an 8F dilator over the wire (D). A high-pressure balloon is positioned with its distal end in the collecting system. As it is inflated a waist at the level of the renal capsule is often the last part to dilate (E). Following inflation an Amplatz sheath is positioned over the balloon (F-example from a second patient). The balloon is deflated and removed, allowing the urologist access to the calculus. After the procedure fluoroscopy demonstrates adequate clearance of the stone (G).

• Fig. 29.25 Percutaneous cyst aspiration. A 22 gauge needle has been postioned within a heavily calcified cyst under CT guidance for diagnostic aspiration.

• Fig. 29.26 CT-guided biopsy. An 18 gauge cutting needle has been positioned in a solid mass in the right renal bed under CT guidance. The core of tissue obtained confirmed recurrent renal cell carcinoma.

• Fig. 29.27 Right renal angiogram showing a small upper pole accessory artery (A). Selective cannulation of the dominant renal artery demonstrates a small peripherally placed renal cell carcinoma (B). A larger renal cell carcinoma is shown on this left renal angiogram (C) with a characteristic malignant circulation (irregular disorganised vessels). Selective embolisation of part of the renal cell carcinoma has been performed (D).

• Fig. 29.27 Right renal angiogram showing a small upper pole accessory artery (A). Selective cannulation of the dominant renal artery demonstrates a small peripherally placed renal cell carcinoma (B). A larger renal cell carcinoma is shown on this left renal angiogram (C) with a characteristic malignant circulation (irregular disorganised vessels). Selective embolisation of part of the renal cell carcinoma has been performed (D).

• Fig 29.28 Pelvic angiography and tumour embolisation. The left internal iliac artery has been cannulated, by manipulating a catheter from the right femoral artery across the bifurcation, and its two major divisions (anterior and posterior) demonstrated (A). The patient is suffering severe immediate postprostatectomy haemorrhage. A coil has been positioned in the anterior divison (B) and the subsequent angiogram demonstrates successful obstruction of flow in this vessel (C). It is rare actually to demonstrate the bleeding point and, given the life threatening situation, it is often worth embolising both sides. Consequently in this case the right internal iliac artery has also been cannulated from the same femoral artery (D) and the anterior division of the internal iliac selectively cannulated (E). This injection shows the inferior vesical artery from which most of the bleeding is probably occurring and therefore this has also been occluded with a coil (F) (see over)

• Fig 29.28 Pelvic angiography and tumour embolisation. The left internal iliac artery has been cannulated, by manipulating a catheter from the right femoral artery across the bifurcation, and its two major divisions (anterior and posterior) demonstrated (A). The patient is suffering severe immediate postprostatectomy haemorrhage. A coil has been positioned in the anterior divison (B) and the subsequent angiogram demonstrates successful obstruction of flow in this vessel (C). It is rare actually to demonstrate the bleeding point and, given the life threatening situation, it is often worth embolising both sides. Consequently in this case the right internal iliac artery has also been cannulated from the same femoral artery (D) and the anterior division of the internal iliac selectively cannulated (E). This injection shows the inferior vesical artery from which most of the bleeding is probably occurring and therefore this has also been occluded with a coil (F) (see over)

• Fig 29.28 Pelvic angiography and tumour embolisation. The left internal iliac artery has been cannulated, by manipulating a catheter from the right femoral artery across the bifurcation, and its two major divisions (anterior and posterior) demonstrated (A). The patient is suffering severe immediate postprostatectomy haemorrhage. A coil has been positioned in the anterior divison (B) and the subsequent angiogram demonstrates successful obstruction of flow in this vessel (C). It is rare actually to demonstrate the bleeding point and, given the life threatening situation, it is often worth embolising both sides. Consequently in this case the right internal iliac artery has also been cannulated from the same femoral artery (D) and the anterior division of the internal iliac selectively cannulated (E). This injection shows the inferior vesical artery from which most of the bleeding is probably occurring and therefore this has also been occluded with a coil (F) (see over)

• Fig. 29.28 (F) with satisfactory clinical response.

• Fig. 29.29 Testicular vein embolisation. The left renal vein has been cannulated via the inferior vena cava (A). A testicular phlebogram performed once the catheter has been advanced down the testicular vein reveals a double testicular vein with multiple origins unprotected by valves, one of a number of variants associated with varicocele formation (B). The upper end of the varicocele is just visible once the catheter has been advanced to the inguinal ring (the varicocele itself should not be screened, to avoid irradiating the testicles) (C). The main testicular vein is occluded with multiple (2-4) coils along its length. Two are illustrated here (D). The most important is the distal one that also occludes the entry of the accessory testicular vein.

• Fig. 29.29 Testicular vein embolisation. The left renal vein has been cannulated via the inferior vena cava (A). A testicular phlebogram performed once the catheter has been advanced down the testicular vein reveals a double testicular vein with multiple origins unprotected by valves, one of a number of variants associated with varicocele formation (B). The upper end of the varicocele is just visible once the catheter has been advanced to the inguinal ring (the varicocele itself should not be screened, to avoid irradiating the testicles) (C). The main testicular vein is occluded with multiple (2-4) coils along its length. Two are illustrated here (D). The most important is the distal one that also occludes the entry of the accessory testicular vein.

• Fig. 29.30 Transverse CT through the midpart of the kidneys. Prior to contrast the kidneys are of intermediate density (A), similar to liver, spleen and blood vessels. During the nephrogram phase the cortex is seen to enhance earlier than the medullary pyramids (B).

• Fig. 29.31 Contrast-filled ureters entering the pelvis at the level of the iliac crest, running along the anterior aspect of the psoas muscles (A) and then around mid sacral level crossing the iliac vessels and beginning to turn anteriorly (B).

• Fig. 29.32 CT of the pelvis showing the distal ureters just above the vesicoureteric junctions lying anterior to the seminal vesicles (A). The right ureter happens to contain a bolus of contrast at the time of the scan. (B) shows the ureters at the vesicoureteric junctions with a jet of opacified urine projecting from the right ureter into the bladder. Further interiorly the prostate is seen just projecting into the bladder base (C).

• Fig. 29.32 CT of the pelvis showing the distal ureters just above the vesicoureteric junctions lying anterior to the seminal vesicles (A). The right ureter happens to contain a bolus of contrast at the time of the scan. (B) shows the ureters at the vesicoureteric junctions with a jet of opacified urine projecting from the right ureter into the bladder. Further interiorly the prostate is seen just projecting into the bladder base (C).

• Fig. 29.33 Transverse CT of the prostate with focal calcification. The puborectalis sling is well demonstrated as a thin intermediate-density line encircling the anorectal junction and the prostate.

• Fig. 29.34 MRI scan of the normal kidneys. On the T,-weighted sequence A) the renal cortex is seen to be of higher signal than the medulla. The reverse is seen on the T2 -weighted (B) and STIR (C) sequences, with the medulla being of higher signal than the cortex (although both are relatively high signal).

• Fig. 29.34 MRI scan of the normal kidneys. On the T,-weighted sequence A) the renal cortex is seen to be of higher signal than the medulla. The reverse is seen on the T2 -weighted (B) and STIR (C) sequences, with the medulla being of higher signal than the cortex (although both are relatively high signal).

• Fig. 29.35 MRI scan of the kidneys 30 s (A) and 90 s (B) following intravenous gadolinium showing the intense enhancement of the cortex and then both the cortex and the medulla.

• Fig. 29.36 MRI of the pelvis on the T,-weighted sequence at the level of the bladder (A) and the prostate (B). The same levels (on a different patient) are seen on the T 2 - weighted sequence (C,D) demonstrating the increased conspicuity of the bladder wall and the zonal anatomy of the prostate. Both sequences show the puborectalis sling well. The same levels are also shown on the STIR sequences (E, F).

• Fig. 29.36 MRI of the pelvis on the T,-weighted sequence at the level of the bladder (A) and the prostate (B). The same levels (on a different patient) are seen on the T 2 - weighted sequence (C,D) demonstrating the increased conspicuity of the bladder wall and the zonal anatomy of the prostate. Both sequences show the puborectalis sling well. The same levels are also shown on the STIR sequences (E, F).

• Fig. 29.36 MRI of the pelvis on the T,-weighted sequence at the level of the bladder (A) and the prostate (B). The same levels (on a different patient) are seen on the T 2 - weighted sequence (C,D) demonstrating the increased conspicuity of the bladder wall and the zonal anatomy of the prostate. Both sequences show the puborectalis sling well. The same levels are also shown on the STIR sequences (E, F).

• Fig. 29.37 Normal 99 '°Tc-DMSA study. LPO = left posterior oblique; POST = posterior; RPO = right posterior oblique.

• Fig. 29.38 Horseshoe kidney. 99"'Tc-DMSA showing bridging renal tissue between the lower poles of both kidneys.

• Fig. 29.39 Ectopic kidney. 99mTc-DMSA study showing right kidney in normal position; left kidney lying in the midline of the pelvis superior to the bladder.

• Fig. 29.40 Bilateral Wilms' tumours. 99 mTc-DMSA study showing extensive replacement of the left kidney; smaller tumour at the hilum of the right kidney.

• Fig. 29.41 Post infective scarring. 99mTc-DMSA study showing normal left kidney; scarred right upper pole (arrows).

• Fig. 29.42 Normal 99mTc-MAG3 dynamic renal study: (A) Part of the first-pass acquisition showing perfusion of aorta and both kidneys; (B) selected images from the excretion series with symmetrical uptake and clearance from both kidneys; (C) renogram curves from the perfusion sequence in the first 30 s (left) and the excretion curves up to 30 min (right). LK = left kidney; RK = right kidney; Ao = aorta.

• Fig. 29.42 Normal 99mTc-MAG3 dynamic renal study: (A) Part of the first-pass acquisition showing perfusion of aorta and both kidneys; (B) selected images from the excretion series with symmetrical uptake and clearance from both kidneys; (C) renogram curves from the perfusion sequence in the first 30 s (left) and the excretion curves up to 30 min (right). LK = left kidney; RK = right kidney; Ao = aorta.

• Fig. 29.43 Unilateral PUJ obstruction. 99 mTc-MAG3 images at 1 min (A), 5 min (B) and 15 min (C), showing typical left hydronephrosis with normal clearance from the right kidney. Renogram curves (bottom right) show normal clearance on the right and an obstructed left side. LK = left kidney; RK = right kidney; B = bladder.

• Fig. 29.44 Dilated but unobstructed renal pelvis. 99 mTc images at 5, 10 and 15 min show rapid uptake and clearance from the left kidney; slower clearance from the right kidney. Renogram curves (bottom right) show normal left side and delayed peak on the right with rapid washout following furosemide (frusemide) injection. LK = left kidney; RK = right kidney; B = bladder.

• Fig. 29.45 Low-grade obstruction. 99 nTc-MAG3 diuretic study images at 1,5 and 20 min show normal uptake and clearance on the right; normal uptake on the left but incomplete clearance. Renogram curves (bottom right) show normal right side and normal uptake on the left but after an initial fall the excretion curve rises again (Homsy's sign). LK = left kidney; RK = right kidney; B = bladder.

• Fig. 29.46 Right renal artery stenosis. 99m -Tc-MAG3 dynamic study shows reduced blood flow to the smaller right kidney on the perfusion series (A), delayed excretion on the 15 min image (B), and the renogram curve (C) shows reduced uptake, delayed T max and slower clearance from the right kidney. LK = left kidney; RK = right kidney.

• Fig. 29.47 Acute tubular necrosis. 99mTc-MAG3 study shows perfusion of both kidneys is reduced (A) and excretion images at 1 min (B) and 20 min (C) show persistent retention of the tracer in the kidney with no excretion. Renogram curves (D) show immediate uptake but no clearance. LK = left kidney; RK = right kidney.

• Fig. 29.48 Acute oliguria after renal transplantation. Anterior perfusion phase images from 99mTc-DTPA study show that blood flow to the transplanted kidney in the right iliac fossa is well maintained. Diagnosis: acute tubular necrosis.

• Fig. 29.49 Acute oliguria after renal transplantation. Anterior view dynamic images 2, 5 and 10 minutes after injection of 99mTc-DTPA show a photon deficient area which represents the totally ischaemic graft in the left iliac fossa; diagnosis: renal vein thrombosis.

• Fig. 29.50 Acute oliguria after renal transplantation. Anterior view perfusion images (A) and excretion images at 1 min (B) and 20 min (C) show severely impaired perfusion of the transplant kidney in the right iliac fossa with slowly increasing uptake but hardly any excretion to the bladder. Renogram curve (D) shows the typical flat curve of a badly-functioning kidney but without the initial vascular spike usually seen with acute tubular necrosis. Diagnosis: severe rejection.

• Fig. 29.51 Suspected obstruction in renal transplant. 99mTc-DTPA study shows good uptake at 2 min (left) with activity reaching the bladder via a distended ureter and collecting system at 20 min (right). Diagnosis: obstruction confirmed.

• Fig. 29.52 Sudden deterioration in renal transplant function.m9Tc-DT9PA study shows normal uptake at 2 min (left); at 20 min (right) some activity is draining via a bladder catheter (C) but much of the activity is leaking into the peritoneal cavity (L). Diagnosis: ureteric leak.

• Fig. 29.53 Radionuclide cystography showing reflux. Selected images from the dynamic sequence obtained during micturition (left) show tracer appearing in the right kidney and ureter as the bladder empties (arrows). Time-activity curves over left and right ureters (right) show no reflux on the left and mild but prolonged episodic reflux on the right.

• Fig. 29.54 Set-up for lower urinary tract urodynamics.

• Fig. 29.55 Renal ultrasound. Corona) (A) and transverse (B) images of a neonatal kidney demonstrating prominent hypoechoic medullary pyramids and no renal sinus fat.

• Fig. 29.56 Renal ultrasound. Coronal (A) and transverse (B) images of the kidney of a 10-year-old child. The medullary pyramids are less conspicuous than in the neonatal period and there is now some echogenicity around the renal hilum.

• Fig. 29.57 Micturating cystourethrogram-male. An oblique voiding image demonstrates the whole urethra with no foreshortening. The filling defect in the posterior urethra represents the verumontanum.

• Fig. 29.58 Micturating cystourethrogram-female. A supine voiding image in a female child. The urethra is shorter than the male and is straight.

• Fig. 29.59 Computed tomography. Axial image through renal hilum shows clearly the left renal vein and right renal artery. There is prominent fetal lobulation and corticomedullary differentiation.

• Fig. 29.60 Molecular structure of the building block for water-soluble contrast media.