RADIO SUMMARY

Fluoroscopy using IV iodinated contrast

What physical mechanism or technique is utilized in Intravenous Pyelography (IVP)?

Evaluation of renal excretory function, congenital anomalies, ureters, and bladder

What are the primary indications for Intravenous Pyelography (IVP)?

CT Urography

Which imaging modality has largely replaced Intravenous Pyelography (IVP) in clinical practice?

1 minute post-injection

What is the timing of the nephrogenic phase during Intravenous Pyelography (IVP)?

15 minutes post-injection

What is the timing of the excretory phase during Intravenous Pyelography (IVP)?

Renal outline, pelvicalyceal system, ureters, and bladder

Which anatomical structures are visualized during the 15-minute excretory phase of IVP?

Creatinine clearance pre-screening to evaluate baseline renal function

What mandatory safety screening is required prior to performing Intravenous Pyelography (IVP)?

45% sensitivity and 77% specificity

What are the diagnostic sensitivity and specificity of IVP for plain film urinary lithiasis?

High-frequency sound waves

What physical mechanism is used to generate images in Ultrasound (US)?

Initial evaluation of renal parenchyma, mass lesions, cysts, obstruction, hydronephrosis, and bladder

What are the primary indications for renal Ultrasound (US)?

Less echogenic than the liver, but more echogenic than the renal medulla

How does normal renal cortex echogenicity compare to the liver and medulla on Ultrasound?

Anechoic triangular regions

How does the normal renal medulla appear on Ultrasound?

Hyperechoic central echo complex composed of fat and pelvis

How does the normal renal sinus appear on Ultrasound?

Thin anechoic slit

How does the normal renal pelvis appear on Ultrasound?

It does NOT require creatinine clearance screening

What is a major safety advantage of Ultrasound regarding renal function screening?

Operator dependency, bowel gas obscuring ureters/retroperitoneum, and air limiting the acoustic window

What are three major technical limitations of Ultrasound in urinary tract evaluation?

Ionizing radiation with IV iodinated contrast

What physical mechanism and contrast agent are used in Contrast-Enhanced CT?

Modality of choice for RCC evaluation and staging, cystic mass characterization, and acute or emphysematous pyelonephritis

What are the primary indications for Contrast-Enhanced CT in urinary tract disease?

Hyperattenuating enhancement of calyces, cortex, and medulla, alongside high-resolution staging of perinephric fat, venous involvement, and lymph nodes

What are the key radiological findings on Contrast-Enhanced CT?

Creatinine clearance screening prior to IV iodinated contrast administration

What safety rule must be strictly followed before ordering a Contrast-Enhanced CT scan?

Contrast-induced nephropathy and anaphylaxis in allergic patients

What are two major medical risks associated with IV iodinated contrast administration?

Non-contrast CT using ionizing radiation

What physical technique is used in a CT Stonogram?

Gold standard and most accurate imaging modality for diagnosing urinary tract lithiasis

What is the primary clinical indication for a CT Stonogram?

Directly visualizes calcific opacities, stone location, size, and secondary hydronephrosis without contrast interference

What key radiological findings are evaluated on a CT Stonogram?

Avoids contrast administration risks while providing maximum accuracy for stones

What is the primary safety benefit of a CT Stonogram?

Magnetic waves (utilizing T1-weighted and T2-weighted sequences)

What physical mechanism is used in Magnetic Resonance Imaging (MRI)?

"Problem-solving modality" reserved for complex mass lesions, contrast allergies, or severe renal impairment

What is the primary clinical role of MRI in urinary tract imaging?

Hyperintense (bright) fluid and cysts

What is the characteristic appearance of fluid and cysts on T2-weighted MRI?

T1 hypointense and T2 hyperintense intraluminal soft tissue masses

What are the T1-weighted and T2-weighted signal characteristics of bladder neoplasms on MRI?

Gadolinium contrast requires creatinine clearance screening due to the risk of Nephrogenic Systemic Fibrosis (NSF)

What safety screening rule applies to MRI contrast administration, and what disease does it prevent?

High cost and limited availability

What are two major practical limitations of MRI?

Fluoroscopic bladder filling with contrast dye during active micturition

What technique is performed during Voiding Cystourethrography (VCUG)?

Standard evaluation for Vesicoureteral Reflux (VUR) and urethral or bladder outlet pathology

What are the primary indications for VCUG?

Retrograde contrast flow from the bladder into the ureters or pelvicalyceal system

What radiological finding on VCUG confirms the diagnosis of Vesicoureteral Reflux (VUR)?

Invasive urethral catheterization is required

What is a key procedural requirement and limitation of VCUG?

Congenital Anomaly

In what disease category is Renal Agenesis classified?

Complete failure of renal development, which may be unilateral or bilateral

What is the underlying pathophysiology of Renal Agenesis?

Total absence of one kidney accompanied by compensatory hypertrophy of the contralateral kidney

What key imaging finding characterizes unilateral Renal Agenesis?

Multimodality confirmation using US and CT to rule out renal ectopia or severe atrophy

What diagnostic evaluation is required to confirm Renal Agenesis?

Fusion of lower renal poles across the midline anterior to the aorta

What is the underlying pathophysiology of Horseshoe Kidney?

Fusion of inferior poles via a tissue isthmus located anterior to the aorta on transverse US and axial CT

What key imaging finding confirms a Horseshoe Kidney?

Incomplete or failed fusion of upper and lower pole moieties

What is the underlying pathophysiology of Ureteral Duplication?

Duplex collecting system featuring two separate pelvicalyceal moieties with partial or complete separate ureters

What key imaging finding characterizes Ureteral Duplication?

Incomplete recanalization of the ureter at 10 to 12 weeks of organogenesis

What is the underlying pathophysiology of Ureteropelvic Junction (UPJO) Obstruction?

Constricted ureteropelvic junction with marked ballooning and dilation of the renal pelvis in the absence of calculi or mass

What key imaging finding characterizes UPJ Obstruction?

Persistence of the posterior cardinal vein causing the right ureter to loop behind the Inferior Vena Cava

What is the underlying pathophysiology of Retrocaval Ureter?

Right ureter courses posterior to and wraps around the IVC, producing proximal hydroureteronephrosis

What key imaging finding confirms a Retrocaval Ureter?

Primary malignant epithelial tumor of the kidney, accounting for 85% of adult primary renal neoplasms

What defines Renal Cell Carcinoma (RCC)?

Heterogeneous mass with necrosis that appears hypodense on CT and hypoechoic or heterogeneous on US

What are the key imaging characteristics of RCC?

CT contrast enhancement greater than 15 to 20 Hounsfield Units (HU)

What CT density measurement change confirms RCC enhancement?

Robson Staging System (Stages I–IV)

What staging system is used to classify Renal Cell Carcinoma?

Tripartite benign tumor composed of blood vessels, smooth muscle, and fat

What is the composition and nature of an Angiomyolipoma?

Well-circumscribed, highly hyperechoic nodule on US due to high fat content, appearing as a hypodense fat-attenuation mass on CT

What are the key US and CT findings in Angiomyolipoma?

Secondary involvement from systemic Non-Hodgkin's Lymphoma

What is the underlying pathophysiology of Renal Lymphoma?

Multiple hypodense renal masses or diffuse bilateral renal enlargement on contrast-enhanced CT

What key CT findings characterize Renal Lymphoma?

Well-defined, smooth-walled, strictly anechoic structure displaying posterior acoustic enhancement on US, and homogeneously hypodense attenuation on CT

What are the classic US and CT findings of a Simple Renal Cyst?

Bosniak Classification (Categories I–IV)

What system is used to categorize complex renal cysts on CT?

Inherited genetic disorder classified as Type III Fetal Cystic Disease

What is the etiology and classification of Autosomal Dominant Polycystic Kidney Disease (ADPKD)?

Massive bilateral renal enlargement replaced by innumerable variable-sized cysts, creating a "bunch of grapes" appearance

What key imaging appearance characterizes ADPKD?

Non-heritable pediatric dysplasia classified as Type II Fetal Cystic Disease

What is the etiology and classification of Multicystic Renal Dysplasia?

Unilateral in males or bilateral in females multi-cystic renal transformation

What is the laterality pattern and imaging manifestation of Multicystic Renal Dysplasia?

Multicystic Renal Dysplasia

What is the most common cause of pediatric renal agenesis or dysplasia?

Ascending urinary tract infection most commonly caused by Escherichia coli or Enterococcus faecalis

What is the primary etiology and pathway of Acute Pyelonephritis?

Contrast-Enhanced CT Scan

What is the diagnostic imaging modality of choice for Acute Pyelonephritis?

Edematous, enlarged kidney displaying wedge-shaped heterogeneous perfusion, blurred sinus fat, or necrotic foci

What key CT findings characterize Acute Pyelonephritis?

Severe necrotizing infection caused by gas-forming bacteria such as E. coli, Klebsiella pneumoniae, and Proteus mirabilis

What is the underlying etiology of Emphysematous Pyelonephritis?

Parenchymal destruction with focal or diffuse intrarenal gas or air appearing as black low-attenuation collections on CT

What key CT finding characterizes Emphysematous Pyelonephritis?

Recurrent infection secondary to pediatric Vesicoureteral Reflux (VUR) or adult obstructive calculi

What is the underlying cause of Chronic Pyelonephritis / Reflux Nephropathy?

Focal cortical scar directly overlying a blunted, dilated calyx accompanied by overall parenchymal thinning

What is the radiological hallmark of Chronic Pyelonephritis?

Extrapulmonary granulomatous infection, with 10% of cases associated with active pulmonary tuberculosis

What is the etiology of Renal Tuberculosis?

Parenchymal cavities, scarring, mucosal thinning, fibrotic strictures, sterile pyuria, and irregular parenchymal or calyceal calcifications

What key radiological and clinical findings characterize Renal Tuberculosis?

End-stage renal parenchymal fibrosis leading to progressive loss of functional nephrons

What is the underlying pathophysiology of End-Stage Renal Disease (ESRD)?

Shrunken kidneys (<9 cm) with diffusely increased/hyperechoic parenchymal echogenicity and loss of corticomedullary differentiation

What key imaging triad characterizes ESRD on Ultrasound?

Calcium deposition within the renal parenchyma, categorized as Cortical (

What defines Nephrocalcinosis?

Echogenic/hyperechoic pyramids on US, and dense calcific rimming of pyramids on plain radiograph or CT

What key imaging findings characterize Medullary Nephrocalcinosis?

Crystal aggregation originating as Randall's plaques in collecting ducts or papillae

What is the initial pathophysiological mechanism of Urolithiasis?

Hyperechoic focus within the renal sinus or ureter producing strong posterior acoustic shadowing

What key Ultrasound finding confirms Urolithiasis?

Dense hyperattenuating opacity

How does Urolithiasis appear on a CT Stonogram?

Pelvicalyceal dilation secondary to mechanical obstruction, VUR, or polyuria

What is the underlying pathophysiology of Hydronephrosis?

Expansion of the pelvicalyceal system appearing as anechoic fluid collections replacing the normal hyperechoic sinus

What key Ultrasound finding characterizes Hydronephrosis?

Neurological disruption of detrusor and sphincter control

What is the underlying cause of Neurogenic Bladder?

Severely thickened, irregular "trabeculated" bladder wall with reduced bladder capacity

What key imaging finding characterizes Neurogenic Bladder?

Inflammatory, infectious, radiation, or drug-induced bladder irritation

What are the etiologies of Cystitis?

Diffuse, uniform mucosal thickening of the urinary bladder wall on US and CT

What key imaging finding characterizes Cystitis?

Chronic infection by Schistosoma or Mycobacterium tuberculosis

What underlying chronic infections produce Bladder Wall Calcification?

Continuous or curvilinear hyperdense calcification lining the bladder wall on plain X-ray or CT

What key imaging finding confirms Bladder Wall Calcification?

Transitional Cell Carcinoma (most common) or Squamous Cell Carcinoma

What are the primary cell types in Bladder Neoplasms?

Focal intraluminal soft tissue mass arising from the bladder wall that appears T1 hypointense and T2 hyperintense on MRI

What key imaging finding characterizes a Bladder Neoplasm?

Cystic dilatation of the intravesical distal ureter near the ureterovesical junction (UVJ)

What is the definition and pathophysiology of a Ureterocele?

Smooth, round, thin-walled intraluminal "cobra-head" filling defect at the bladder base on IVP or US

What key imaging finding characterizes a Ureterocele?

Herniation of bladder mucosa through detrusor muscular defects

What is the underlying pathophysiology of Bladder Diverticula?

Anechoic/fluid-filled extraluminal pouch communicating with the main bladder lumen, with a risk of fistula formation

What key imaging finding and potential complication characterize Bladder Diverticula?

Retroperitoneal space at the T12 to L3 vertebral levels

Where are the kidneys anatomically located in the abdomen?

Paired organs with an oblique orientation where the superior poles are positioned more medially and anteriorly

What is the anatomical orientation of the kidneys?

Right kidney lies adjacent to the liver; its cortex is normally less echogenic than the liver parenchyma

What is the anatomical relation and normal comparative echogenicity of the right kidney?

Male predilection, occurring in 1 in 400 to 500 adults

What is the gender predilection and adult prevalence of Horseshoe Kidney?

Isthmus crosses anterior to the abdominal aorta

How is the tissue isthmus of a Horseshoe Kidney positioned relative to major abdominal vessels?

RIGHT ureter is ALWAYS affected

Which ureter is specifically involved in a Retrocaval Ureter?

Right ureter passes posterior to and wraps around the Inferior Vena Cava (IVC)

What anatomical path does a Retrocaval Ureter follow?

Unilateral in 98% of cases, and bilateral in 2%

What is the laterality distribution of Renal Cell Carcinoma?