Presentation on theme: "Urinary tract The four basic examination of the urinary tract:ultra sound,IVU,CT,radionuclide examinations MRI and arteriography:limited to selected patients."— Presentation transcript:
Urinary tract The four basic examination of the urinary tract:ultra sound,IVU,CT,radionuclide examinations MRI and arteriography:limited to selected patients (FDG-PET)CT is still under investigations Ultrasound,CT,MRI are essentially used for anatomical information Radionuclide examintaions provide functional information IVU provides both functional and anatomical information
Imaging techniques Ultrasound:is the first-line investigation in most patients,providing anatomical information without requiring ionizing radiation or the intravenous contrast medium The main uses: Investigate patients with symptoms through to arise from the urinary tract Demonstrate the size of the kidneys,exclude hydronephrosis in patients with renal failure Diagnose hydronephrosis,renal tumours,abscesses and cysts Assess the follow-up renal size and scarring in children with urinary tract infection Assess the bladder and prostate
tumors calcifications hydronephrosis Normal kidney
Intravenous urography or CT urography CT urography When detailed demonstration of the pelvicaliceal system and ureters are required Investigation of renal calculi Suspected ureteric injury,e.g.following pelvic surgery or trauma Investigation of haematuria Assessment of acute ureteric colicCharacterization of a renal mass Staging and follow-up of renal carcinoma To delinate renal vascular anatomy to diagnose or exclude renal trauma
Cont.. MRI : gives similar anatomical to information to CT,with the advantages of: Being able able to obtain scans directly in the coronal,sagittal and oblique planes in addition to the axial plane Used in selected circumstances,e.g.renal artery stenosis or inf vena caval extension of renal tumors or to clarify problems not solved by ultrasound or CT Assess the extent of bladder or prostate cancer prior to consideration for surgery Disadvantages: calcification is not visible on MRI
Duplicated collecting system by ultrasound(A),MR(B,C)
Cont.. Radionuclide examintion : Radionuclide techniques for studying the kidneys include: The renogram wich measures renal function Scans of renal morphology The presence of reflux in children may be diagnosed using the technique of indirect voiding cystography. Renogram : The main indications : Measurement of relative renal function in each kidney Investigation of urinary tract obstruction Investigation of renal transplants
Retrograde and antegrade pyelography : The indications are limited to those situations where the information can not be achieved by less invasive means,e.g.IVU,CT or MRI to confirm a possible transitional cell carcinoma in the renal pelvis or ureter Urethrography : The indications:indications of urethral strictures and to demonstrate extravasation from the urethra or bladder neck following trauma Renal artetriography : It is mainly used to confirm the CT or MRI findings and to confirm renal artery stenosis.
Urinary tract disorders: Urinary calculi: plain film examination of the urinary tract is more sensitive than ultrasound for detecting opaque renal and ureteric calculi. CT,when performed without intravenous contrast medium,is exquisitely sensitive for the detection of calculi. It is used in place of IVU for the detection and precise anatomical localization of stones prior to treatment in most centres.
nephrocalcinosis Is the term used to describe focal or diffuse calcification within the renal paranchyma
Urinary tract obstruction Ultrasound and urographic examination play major roles when evaluating urinary tract obstruction and CT urography has overtaken IVU for the investigation of obstruction.radionuclide studies show typical changes,but are rarely the primary imaging procedures. ultrasound: It is often not possible to determine the cause of urinary tract obstruction at ultrasound examination.ultrasound may demonstrate a pelvic mass,such as a uterine or ovarian mass,causing external compression of the collecting system.
Puj obstruction Duplex left collecting system with a puj obstruction in lower pole moiety MRI.puj obstruction
Cont. IVU :in some centres,the ivu remains the primary imaging modality in patients with suspected acute obstruction,wich is usually caused by a calculus. CT :is now widely used to evaluate urinary tract obstruction.in acute obstruction,non-contrast enhanced CT sensitively demonstrates calculi and unopacified,dilated collecting system can frequently be traced down to the point of obstruction.non-contrast CT is often used in acute ureteric colic,as an alternative to IVU,in patients with an allergy to intravenous contrast medium.CT also has the advantage of demonstrating possible alternative causes of acute abdominal pain,such as appendicitis.chronic obstruction by tumour either within the renal collecting system or by an external tumour causing compression,may be visualized directly on CT or MRI and staging of the tumour can be performed during the same investigation.
Congenital intrinsic pelviureteric junction(PUJ)obstruction In this disorder,peristalsis is not transmitted across the pelviureteric junction.the diagnosis depends on identifying the dilatation of the pelvis and calices,with an abrupt change in caliber at the pelviureteric at all. Puj obstruction can be difficult to distinguish on IVU from otherwise normal.(see figs in slide 17) Extrinsic causes of obstruction Tumours.carcinoma of the cervix,ovary and rectosigmoid colon and malignant lymph node enlargement are frequent causes in category of ureteric obstruction CT is the ideal method of diagnosis because it shows the tumour mass as well as the level of obstruction.
Cont. Retroperitoneal fibrosis In most cases,no cause can be found for this benign fibrotic condition,which encases the ureters and causes obstruction CT is the best diagnostic method of choice. Retroperitoneal fibrosis Carcinoma of Rectosigmoid colon
Renal parenchymal masses Almost all solitary masses arising within the renal parenchyma are either mailgnant tumours or simple cysts. Multiple renal masses include: multiple simple cysts Polycystic disease Malignant lymphoma Metastases Inflammatory masses
Cont. Ultrasound: When the ultrasonographer is sure that the diagnosis is a simple cyst,no further investigation is needed.indeterminate lesions with both cystic and solid components need further evaluation with CT. Angiomyolipomas are a fairly frequent incidental finding at ultrasound,appearing as small echogenic masses.CT or MRI may be used to confirm the diagnosis.
IVU.cont. The initial diagnosis of a renal mass is now rarely made on IVU,as ultrasound and CT are the usual primary modalities. Once a mass is seen or suspected at IVU,the next step is to diagnose it’s nature using ultrasound or CT.
CT and MRI of renal masses CT has proved very useful for characterizing indeterminate renal masses identified on ultrasound.CT may be used to differentiate cysts from tumours,to diagnose angiomyolipomas,and to stage renal carcinoma.renal masses may be characterized on MRI,but MRI is usually reserved for solving specific problems. Angiomyolipomas are usually incidental findings.they are benign tumours,which rarely cause problems,although,on occasion,they cause significant retroperitonal haemmorrhage.at CT and MRI,their fat content allows a confident diagnosis. The CT diagnosis of renal carcinoma is usually sufficiently accurate so that preoperative biopsy is rarely performed. Staging of renal cell carcinoma is usually undertaken with CT,the current method of choice,CT, shows local direct spread,can demonstrate enlargement of draining lymph nodes in the retroperitoneum,diagnose live,adrenal and pancreatic metastases and show tumour growing along the renal vein in to the infrior vena cava.
Urethelial tumors Almost all tumours that arise within the collecting systems of the kidneys are transitional cell carcinomas. In some centres,the IVU plays an important role in demonstrating the upper tract. it is easy to confuse tumors with overlying gas shadows on an IVU,and tomograohy or ultrasound may be required to solve the problem. CT plays an important role in confirming or ruling out radiolucent calculi. CT urography demonstrates thickening of the wall of the ureter at the site of a uothelial tumour.the ureter is often obstructed at the level of a TCC.
Acute pyelonephritis Is usually due to bacterial infection from that organisms that enter the urinary system via the urethra.anatomical abnormalities such as stones,deplex,..predispose to infection.in patients presenting with signs of infection associated with pain,if the symptoms are not settling with antibiotics,ultrasound and plain films may diagnose underlying stones,obstruction or abscess formation.in some cases if the pain is severe,an IVU or CT KUB may be done to demonstrate or rule out acute ureteric colic.ultrasound of the kidneys may demonstrate underlying obstruction or stones.many hospitals do a DMSA to demonstrate scarring.
Renal and perinephric abscesses Ultrasound is the initial imaging investigation in most suspected renal abscesses,although in patients who are very unwell CT is often the first imaging investigation. With CT,it is possible to see enhancement of the wall of the abscess following intravenous contrast injection.
pyonephrosis Pyonephrosis only occurs in collecting systems that are obstructed.ultrasound is the most useful imaging modality for pyonephrosis.in addition to showing the dilated collecting system,it may demonstrate multiple echoes within the collecting system from infected debris.
tuberculosis Follows blood-borne spread of mycobacterium tuberclosis,usually from a focus of infection in the lung.in the early stages of the disease,the ultrasound and IVU may be normal. Ultrasound may demonstrate calcifications and pelvicaliceal dilataion and cavities,but the appearances are non-specific.CT can sensivitively demonstrate early calcifications,small cavities and external spread.