Emphysematous pyelonephritis refers to a morbid infection of kidneys, with characteristic gas formation within or around the kidneys. If not treated early, it may lead to fulminant sepsis and carries a high mortality.
The patient usually presents with flank pain, urinary ...
Empyemas are purulent inflammatory collections within a body cavity. They are similar to abscesses, which arise within parenchymal tissue rather than occupying a pre-existing anatomical space.
Colloquially, the term empyema is used to refer to thoracic empyemas but there are variou...
Endometrial carcinoma staging allows appropriate treatment options to be considered and enables greater prognostic accuracy for endometrial carcinoma.
Staging can be based on the TNM or FIGO system.
MR imaging is the modality of choice for staging with CT having relatively low speci...
End-stage kidney disease (ESKD), also referred as end-stage renal failure, corresponds to the last stage of a chronic kidney disease (stage 5), when the kidneys function is no longer sufficient to sustain life (GFR <15) and kidney replacement therapy (dialysis or transplant) is required.
Eosinophilic ureteritis (and eosinophilic pyelouerteritis) is a rare cause of ureteral inflammation. The clinical presentation and imaging features are non-specific.
Patients are usually atopic or hypereosinophilic with peripheral eosinophilia.
Associated with eosinophil...
The term epidermoid cyst can refer to a:
epidermal inclusion cyst
intracranial epidermoid cyst
splenic epidermoid cyst
spinal epidermoid cyst
testicular epidermoid cyst
An epididymal abscess is an uncommon complication of epididymitis.
Causative organisms are the same that cause epididymitis:
Other rare aetiological agents
An epididymal appendix (or alternatively appendix of the epididymis or appendix epididymis) is a testicular appendage that is a developmental remnant of the mesonephric duct (Wolffian duct) which can be found in the head of the epididymis 1. In 78% of the cases, it is stalked and is thus easily ...
Epididymal calcification can be seen on ultrasound as hyperechoic foci within the epididymal head. If the calcifications are large enough, then they may demonstrate acoustic shadowing.
chronic epididymitis: e.g. bacterial, granulomatous (TB) or genital filariasis
Epididymal cysts are the most common epididymal mass.
Epididymal cysts have been reported in ~30% (range 20-40%) of asymptomatic individuals 5.
They are usually of lymphatic origin 2. The cysts contain clear serous fluid, lymphocytes, spermatozoa and debris.
Epididymal masses are most commonly encountered on ultrasonography. Most epididymal masses are benign; malignant lesions are rare.
adenomatoid tumour of the scrotum (most common epididymal mass 4)
sperm granulomas / post vasectomy gra...
The epididymis (plural epididymides) is situated adjacent to the testis within the scrotal sac. Its primary function is the collection, maturation and transport of sperm via the ductus deferens.
The epididymis is an elongated structure, posterolateral to the testis. It can be sub...
Epididymitis refers to inflammation of the epididymis, and may be associated with inflammation extending to the testis itself, in which case the term epididymo-orchitis is used. This should be distinguished from isolated orchitis, which is by comparison much less common.
Epispadias is a rare congenital anomaly that is almost always associated with bladder exstrophy.
It occurs in 1 in 30,000 births, with a male: female ratio of 3:1.
The roof of the urethra is absent and the urethra opens anywhere between the base and the gl...
The erased charcoal sign usually describes the typical lenticular or water drop lesion of a homogeneous low T2WI focal prostate cancer with an ill-defined border within the transition zone.
Multiple criteria are used to detect extracapsular extension of prostate cancer. They include 3:
an irregular bulge in capsule
obliteration of the rectoprostatic angle
asymmetry of the neurovascular bundle
angulation/step-off appearance to the tumour
focal capsular retraction and or thicken...
Extracorporeal shock wave lithotripsy (ESWL) is a common non-invasive treatment for urolithiasis. It is less successful in obese patients and with stones >2 cm.
steinstrasse: incomplete fragmentation that results in a pile-up of stone fragments that obstruct the ureter
Extrapulmonary tuberculosis (TB) refers to the haematogenous spread of Mycobacterium tuberculosis.
Extrapulmonary tubercuosis can occur as a primary form of the disease, i.e. direct infection of an extrapulmonary organ without the presence of primary pulmonary tuberculosis or it can ...
Extrarenal pelvis refers to the presence of the renal pelvis outside the confines of the renal hilum; it is a normal anatomic variant.
It is found in ~10% of the population 2.
An extrarenal pelvis usually appears dilated, erroneously suggesting...
Extratesticular scrotal masses (non-testicle and non-epididymis) are mostly mesenchymal in origin and benign 1.
lipoma (most common)
leiomyoma of the scrotum
granular cell tumor
fibrous hamartoma of infancy...
A faceless kidney refers to one in which the normal appearance of the renal sinus on cross-sectional imaging is absent. It was initially described as a sign of duplication of the collecting system 1 (a slice obtained between the two collecting systems will not demonstrate the normal components o...
Fanconi syndrome describes generalised proximal renal tubule dysfunction causing impaired reabsorption of many urinary solutes.
Clinical features include poor growth, fatigue, dehydration, polyuria, muscle weakness, and bone pain. Features on a basic blood panel includes...
There are numerous fat-containing renal lesions, including:
renal cell carcinoma
renal or perirenal lipoma/liposarcoma
Non-mass lesions may also occasionally contain fat:
renal junction line
fat in a renal scar
renal sinus lipomatosis
Female prostate sign is a characteristic imaging sign seen in patients with a large urethral diverticulum.
A large urethral diverticulum in females surrounds the urethra, and elevates the base of the bladder, mimicking the typical appearance of enlarged prostate in males.
Female pseudohermaphroditism (FPH) is a form of disorder of gender development.
Patients with female pseudohermaphroditism have female internal genitalia and female karyotype (XX) with various degree of external genitalia virilization.
congenital adrenal hyperplasia (CAH) ...
The female urethra is a simple short tube, that transports the urine out of the body, extending from the internal urethral orifice of the bladder to the external urethral orifice in the vestibule of the vagina.
The female urethra measures approximately 4 cm in length. It is embe...
Fetal cystic renal disease can be in included in three of the four types classified according the system by Osathanondh and Potter 1:
Potter type I: infantile polycystic kidney disease
Potter type II: multicystic dysplastic kidneys
Potter type III: adult polycystic kidney disease
A fetal hydrocele refers to a hydrocele present in utero.
They may be sonographically identified in ~15% of male fetuses in the third trimester 6.
Often result from a patent processus vaginalis. They are more frequently unilateral.
Fetal hydronephrosis represents the abnormal dilatation of the fetal renal collecting system, with pelviureteric junction obstruction the most commonly encountered cause.
Please, refer to the article on fetal pyelectasis for a dedicated discussion on this relatively common and usually benign f...
Fetal megacystis refers to the presence of an unusually large bladder in a fetus.
The estimated incidence of antenatal imaging is at ~1:1500 pregnancies.
It can result from a number of causes but the main underlying mechanism is either a distal stenosis or reflux.
Fetal pyelectasis refers to a prominence of the renal pelvis in utero that is a relatively common finding, which in the majority of cases resolves spontaneously.
Please refer to the article on fetal hydronephrosis for a continued discussion on this matter.
Although there is an ...
A fetal urachal cyst refers to a urachal cyst occuring in utero. It may or may not communicate with the vertex of the fetal bladder. It may also arise within the umbilical cord. Umbilical cord urachal cysts originate from an extra-abdominal urachal system.
fetal intra-abdominal cysts...
Fetal urinary ascites is one of the causes of fetal ascites and can arise from a number of pathologies.
in utero bladder perforation
transudation from the fetal bladder
persistent urogenital sinus
The presence of fetal ascites without...
Fibrous pseudotumour of the scrotum is a relatively rare, non-neoplastic extratesticular non-epididymal lesion.
It affects any age. Although rare, it is considered the third most common extra testicular mass after a scrotal lipoma and an epididymal adenomatoid tumour.
The filarial dance sign refers to a twirling motion of microfilariae (e.g. W. bancrofti) noted in dilated lymphatic channels. It is identified as a characteristic sign and indicator of scrotal filariasis.
The dilated channels are identified with absence of color flow on colour Doppler study (CD...
Filariasis refers to infection with nematodes (roundworms) of the family Filariodidea. There are three types of these thread-like filarial worms:
Wuchereria bancrofti: responsible for 90% of cases
Brugia malayi: causes most of the remainder of cases
B. timori: also causes the disease
It can ...
The Finnish type congenital nephrotic syndrome is a sub type of congenital nephrotic syndrome. A large placenta and proteinuria from birth are considered hallmarks of the disease 2. The proteinuria is often of intra-uterine onset. Although it is named the Finnish type, it can occur outside Finla...
Fishhook ureters, also known as J-shaped ureters or hockey stick ureters describe the appearance of the distal ureter in patients with significant benign prostatic hypertrophy. It has also been used to describe the appearance of a retrocaval ureter further up, as the right ureter hooks behind th...
Fluorine-18-labeled sodium fluoride (also known as 18F-NaF or sodium fluoride) is a PET radiotracer used primarily for skeletal imaging.
Fluorine-18-labeled sodium fluoride is an ionic compound comprised of a single sodium atom bound to a positron-emitting isotope of fluorine.
Folliculin gene-associated syndrome (FLCN-S) or Birt-Hogg-Dubé (BHD) syndrome is a genetic multisystemic disease mainly characterised by:
multiple lung cysts and secondary spontaneous pneumothoraces
multiple bilateral renal tumours (particularly chromophobe renal cell cancer and oncocytoma)
The term fornix (plural: fornices) is used for anatomical structures in multiple organ systems that all share an arch-like morphology:
History and etymology
Fornix is Latin for...
The fossa navicularis refers to a normal mild dilatation of the urethra. It occurs at the most distal/downstream portion of the urethra.
It is more evident in males, where it occurs in the penile/pendulous urethra, near the urethral meatus. There is also a fossa navicularis in women: the more f...
The fountain sign is sonographic sign described in acute idiopathic scrotal edema (AISE).
It refers to the appearance of the pattern of vascularity seen during transverse colour Doppler sonography of the scrotum with both testes together1. In these transverse views in patients with AISE, marked...
Fournier gangrene is a necrotising fasciitis of the perineum. It is a true urological emergency due to the high mortality rate but fortunately, the condition is rare.
Fournier gangrene is typically seen in diabetic men aged 50-70 but rarely in women. Other than age, predisposing f...
Fraley syndrome is the eponymous term for a dilated calyx (hydrocalyx) due to compression of a calyceal infundibulum from an adjacent artery or vein. It is rare, but it occurs more often in an upper pole calyx. The hydrocalyx may be painful.
The free/total PSA ratio (%fPSA) is an additional new parameter used in assessing PSA levels. Some authors 1,2 recommend that men with PSA levels of 4.1 to 10 ng/mL who are not suspected of having prostate cancer by whatever means should undergo %fPSA measurement and then be carefully monitored ...
Ganglioneuromas are fully differentiated neuronal tumours that do not contain immature elements and potentially occur anywhere along the peripheral autonomic ganglion sites.
On imaging, usually, they present as well-defined solid masses and can be quite large at presentation. Generally, they a...
There numerous causes of gas in the bladder. In the hospital setting by far the most common is the recent placement of an indwelling urinary catheter. Other causes include:
IDC by far the most common cause
intraluminal and intramural gas
Genitourinary tuberculosis is the second most common site of infection in humans by Mycobacterium tuberculosis, second only to pulmonary tuberculosis.
It can most easily be divided anatomically into:
renal tuberculosis (renal parenchyma, calyces and renal pelvis)
bladder and ureteric tubercu...
Germ cell tumours are classified into two broad groups: seminoma and non-seminomatous germ cell tumours (NSGCT). The later is then divided further according to histology.
non-seminomatous germ cell tumours (NSGCT)
yolk sac tu...
Germ cell tumours are found widely throughout the body, and encompass a wide range of individual tumours.
This article does not deal with any specific body locations. For detailed discussion please refer the articles listed at the end of this page.
Germ cell tumours arise from ecto...
A mnemonic for differential diagnosis for germ cell tumours is:
E: embryonal cell carcinoma
E: endodermal sinus tumour (yolk sac tumour)
Germinoma is a term that if unqualified, usually refers to a tumour of the brain but can also refer to similar tumours of other regions particularly the ovary and testis.
dysgerminoma of the ovary
seminoma of the testis
CNS germinoma: see WHO classification of CNS tumours
All these tumours s...
The Gleason score determines the histological grading of prostate cancer. A score of 1 to 5 is assigned to each of the two largest areas of tumour involvement in the samples obtained, based on the worst feature.
1: least aggressive
5: most aggressive
These two scores are then added together t...
The goblet sign (or champagne glass sign) refers to the appearance of the ureter when it is focally dilated by an intraluminal mass. It is best seen when the ureter is opacified from below, by a retrograde ureterogram. Presence of this sign indicates the pathology to be chronic, permitting the l...
The Goldman classification of urethral injuries is a more widely accepted classification than one proposed by the American Association for the Surgery of Trauma (AAST). The Goldman classification is based on the anatomical location of the urethral injury and was initially proposed by Colapinto a...
The gonadal arteries are the paired primary vascular supply to the ovaries in the female and the testes in the male. As the anatomy of the gonadal arteries differs substantially between the sexes, they are covered separately:
The gonadal veins are paired structures that drain the gonads in males and females. In males it is called the testicular vein and in females it is called the ovarian vein. The gonadal veins ascend with the gonadal arteries in the abdomen along the psoas muscle anterior to the ureters. Like the s...
Gonadoblastomas are uncommon sex cord / stromal tumours. They are associated with disorders of sexual development (previously known as "intersex disorders").
The vast majority are found <30 years of age. Most are discovered in the perinatal period. May occur in phenotypic males or...
Granulomatosis with polyangiitis (GPA), previously known as Wegener granulomatosis, is a multisystem necrotising non-caseating granulomatous c-ANCA positive vasculitis affecting small to medium sized arteries, capillaries and veins, with a predilection for the respiratory system and kidneys 3.
The renal manifestations of granulomatosis with polyangiitis (GPA) (previously known as Wegener granulomatosis) are occult on imaging, especially when compared to the pulmonary changes. Approximately half of GPA patients have kidney disease at presentation. Granulomatosis with polyangiitis is a ...
Granulomatous prostatitis is a nodular form of chronic prostatitis. It is usually diagnosed on biopsy.
Several classification systems exist. A frequently used clas...
The great vessel space is the fourth retroperitoneal space along with the anterior and posterior pararenal spaces, and the perirenal space 1, 2. Unlike other retroperitoneal spaces, it is not well-defined by fascial planes and thus disease process affecting other retroperitoneal spaces can also ...
Growing teratoma syndrome is a rare complication after treatment for metastatic (or in the case of intracranial disease, primary) non-seminomatous germ cell tumours (NSGCT).
It was first described in the paediatric population with treated germ cell neoplasms, and represents enlarging masses at ...
Haematospermia (less commonly haemospermia) refers to the presence of blood in semen or ejaculatory fluid. It is a symptom that can cause great anxiety in patients despite usually being of benign aetiology.
urogenital infections including sexually transmitted disease
Haematuria occurs when blood enters the urinary collecting system and is excreted in the urine. There are many aetiologies for haematuria, and they range from benign and transient to gravely concerning. Haematuria can derive from the kidneys, ureters, bladder, prostate (in men), or urethra. Imag...
Haematuria in a child is evaluated differently than in an adult in two main respects:
there is a lower likelihood of a malignancy (renal or bladder) causing the haematuria
preference is given to nonionizing radiation
Haematuria can be considered in three main forms:
Haemolytic uraemic syndrome (HUS) is a multisystem thrombotic microangiopathic disease characterised by the triad of renal failure, haemolytic anaemia and thrombocytopenia. It is the most common cause of renal failure in infancy and childhood requiring dialysis.
There are two forms of this syn...
The haemorrhage exclusion sign can be a useful MRI finding following prostate biopsy.
The normal prostate produces high concentrations of citrate, which among other properties, acts as an anticoagulant 1. As tumour cells are dysfunctional, they will produce lower levels of citrate th...
Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC) syndrome is an autosomal dominant monogenic COL4A1-related disorder.
The exact prevalence is unknown.
The cardinal features of HANAC syndrome are helpfully described in the name of...
Height adjusted total kidney volume (HtTKV) is used in patients with autosomal dominant polycystic kidney disease to predict the onset of renal insufficiency. There is strong evidence to indicate that baseline htTKV predicts, with good sensitivity and specificity, the development of renal insuff...
Hepatorenal syndrome refers to a form of acute kidney injury caused by changes in renal blood flow regulation due to liver pathology 1. Although the syndrome occurs mainly in cirrhotic livers it has been reported in patients with acute fulminant liver failure as well 1.
Hereditary breast and ovarian cancer (HBOC) syndrome is caused by a mutation to either BRCA1 or BRCA2 genes. These patients have an increased risk of breast cancer, ovarian cancer, pancreatic cancer and prostate cancer. However, these gene mutations are not the only cause of hereditary breast ca...
Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is a recently identified autosomal dominant tumour susceptibility syndrome.
It is characterised by:
predisposition to benign cutaneous and uterine leiomyomas (fibroids, myomas)
susceptibility to early-onset renal cell carcinoma
Despite the vast majority of renal cancers being sporadic, there are a number of hereditary renal cancer syndromes:
von Hippel Lindau syndrome: predominantly clear cell type
tuberous sclerosis: predominantly clear cell type
hereditary leiomyomata renal cell cancer syndrome: described in ISUP ...
Herlyn-Werner-Wunderlich (HWW) syndrome, is a rare anomaly characterised by Müllerian duct anomalies (MDA) associated with mesonephric duct anomalies 3. This entity is also known as obstructed hemivagina and ipsilateral renal anomaly (OHVIRA). It is not to be confused with the Wunderlich syndro...
Heterogeneous testicular echotexture at ultrasound may be the result of a variety of underlying pathology:
seminiferous tubular atrophy - can occur in around 14% of middle aged to elderly patients 2
Genitourinary manifestations of HIV/AIDS are protean and can be divided into:
renal diseases related to opportunistic infections: CMV, tuberculosis and MAC infections, fungal infections, pneumocystis carinii infection
drug-related renal diseases:
HIV-associated neoplasms are numerous and can be broadly divided into two groups:
associated but not AIDS defining malignancies
The development of these malignancies in HIV affected individuals generally implies progression to AIDS 4:
HIV-associated nephropathy (HIVAN) is commonly seen in patients with HIV/AIDS and leads to end-stage renal disease (ESRD). The diagnosis is not imaging-based and must be confirmed by renal biopsy.
HIVAN is seen in patients at advanced stages of HIV and AIDS, but it can also be see...
A horseshoe adrenal gland is a very rare anomaly. It is also sometimes referred to as a butterfly, fused or midline adrenal gland.
It is a solitary adrenal gland that is present in the midline of the fused portion either passing between the aorta and the inferior vena cava or posterior to the a...
Horseshoe kidneys are the most common type of renal fusion anomaly. They render the kidneys susceptible to trauma and are an independent risk factor for the development of renal calculi and transitional cell carcinoma of the renal pelvis.
Horseshoe kidneys are found in approximate...
Hutch diverticula are congenital bladder diverticula, seen at the vesicoureteric junction, in the absence of posterior urethral valves or neurogenic bladder. They are thought to result from a weakness in the detrusor muscle anterolateral to the ureteral orifice.
They occur almost...
Hydroceles are acquired or congenital serous fluid collections between the layers of the tunica vaginalis surrounding a testis or spermatic cord. They are the most common form of testicular enlargement and present with painless enlargement of the scrotum. On all modalities, hydroceles appear as ...
Hydrocele of the canal of Nuck is a rare condition in female children caused by a failure of complete obliteration of the canal of Nuck 1. The canal of Nuck is an abnormal patent pouch of peritoneum extending anterior to the round ligament of the uterus into the labia majora 2. Incomplete oblite...
Hydronephrosis is defined as dilatation of the urinary collecting system of the kidney (the calyces, the infundibula, and the pelvis) 1. The term hydroureteronephrosis (or hydronephroureterosis) is used when the dilatation also involves the ureter.
Hydronephrosis in fetuses and newborns has sp...
Grading systems of hydronephrosis have been devised to communicate the degree of upper collecting system dilatation. The most common system used (Society of Fetal Ultrasound, SFU) was originally designed for grading neonatal and infant hydronephrosis:
no dilatation, calyceal walls are ...
Hyperparathyroidism is the effect of excess parathyroid hormone in the body. It can be primary, secondary, or tertiary. There are many characteristic imaging features, predominantly involving the skeletal system.
Increased levels of the parathyroid hormone lead to increased osteoclas...
Hyper-reninaemic hypertension may have many causes including:
renal artery stenosis
renal secreting tumour, e.g. renal cell carcinoma, reninoma
renal compression: large renal mass, subcapsular haemorrhage (Page kidney)
Columns of Bertin represent the extension of renal cortical tissue which separates the pyramids, and as such are normal structures. They become of radiographic importance when they are unusually enlarged and may be mistaken for a renal mass (renal pseudotumour).
Nomenclature of such enlarged co...
The hypogastric nerves are paired nerve bundles that are part of the autonomic nervous system and located in the pelvis.
origin: contain sympathetic fibres descending from the superior hypogastric plexus and parasympathetic fibres ascending from the inferior hypogast...
Hypospadias refers to a type of congenital malformation affecting the male external genitalia.
The estimated prevalence is ~2 (range 0.2-4.1) per 1000 live births.
The urethral meatus is abnormally positioned proximally and ventrally to its normal position.
It is thou...
Idiopathic retroperitoneal fibrosis (IRF) is a subtype of retroperitoneal fibrosis where no obvious cause is found. It includes a spectrum of diseases which are characterized by fibroinflammatory tissue encasing the abdominal aorta and the iliac arteries. This process may extend into the retrope...