Renal tuberculosis, a subset of genitourinary tuberculosis, accounts for 15-20% of extra-pulmonary tuberculosis and can result in varied and striking radiographic appearances.
Tuberculosis can involve both the renal parenchyma and the collecting system (calyces, renal pelvis, ureter, bladder a...
Renal tubular acidosis (RTA) refers to defects in the renal tubular transport of hydrogen ions, bicarbonate ions, or both, in the kidneys resulting in a normal anion gap metabolic acidosis.
The exact prevalence of renal tubular acidosis is unknown but the entity is probably u...
Renal tubular ectasia is an incidental finding that is seen more commonly on intravenous pyelography (IVP), but which can also occasionally be seen on CT urography (CTU).
Renal tubular ectasia is also known as benign renal tubular ectasia. The term "benign" was used to differentiat...
Renal tumors (for the purposes of this article taken to broadly mean neoplastic lesions) should be distinguished from renal pseudotumors.
Whilst renal tumors can be broadly divided into primary and secondary (metastatic), benign and malignant, or adult and pediatric tumors, they are more formal...
Renal vascular pedicle injury is a severe form of renal trauma, which if not recognized and treated expediently with lead to the loss of the kidney.
Contrast enhanced CT is the Imaging modality of choice. On CT it is recognized as a non-enhaning kidney. Perirenal he...
The renal veins are asymmetric paired veins that drain the kidneys.
The renal vein is formed by the union of two-to-three renal parenchymal veins in the renal sinus. It emerges from the renal hilum anterior to the renal artery and drains into the inferior vena cava at th...
There are several variations in renal venous anatomy. Some of these are specific to the left renal vein.
Left renal vein anomalies are generally classified into four types 2:
the ventral pre-aortic limb of the left renal vein is obliterated, but the dorsal retro-aortic limb persists a...
Renal vein thrombosis can be either from "bland" thrombus or tumor thrombus (extension of tumor into the vein). There are numerous etiologies for bland thrombus, but it most commonly occurs in the hypercoagulable nephrotic syndrome. Renal vein thrombus is commoner on the left side, presumably du...
Renal vein varices develop for various reasons and are usually asymptomatic.
Renal vein varices are usually asymptomatic. Some patients may present with flank pain and/or hematuria.
chronic renal vein thrombosis
Renovascular hypertension (RVH) is a type of secondary hypertension, where high blood pressure develops secondary to renal artery disease.
Approximately 2.5% (range 0.5-5%) of hypertensive patients will have RVH as a cause 2,3.
There are a number of conditi...
Retroaortic left renal vein (RLRV) is a normal anatomical variant where the left renal vein is located between the aorta and the vertebra and drains into the inferior vena cava.
Its recognition is important in order to avoid complications during retroperitoneal surgery or interventional procedu...
Retrograde pyelography (also known as retrograde pyeloureterography) is a method of imaging the upper urinary collecting system. After IVU and CTU were developed, it has been rarely performed as a primary study, but it still has a few potential indications as a secondary study.
Retroperitoneal fibrosis (RPF), is a condition that has previously been described as chronic periaortitis. It is an uncommon fibrotic reaction in the retroperitoneum that typically presents with ureteric obstruction.
The disease is part of a spectrum of entities that have a common pathogenic pr...
Retroperitoneal hemorrhage can be a source of significant yet occult blood loss.
The clinical features are varied depending on the amount of hemorrhage present, rate of onset and ability of the surrounding structures to contain the hemostatic system. The classical feature...
The retropubic space (also known as the prevesical space, cave of Retzius or cavum Retzii) is an extraperitoneal space located posterior to the pubic symphysis and anterior to the urinary bladder. It is separated from the anterior abdominal wall by the transversalis fascia and extends to the lev...
The reverse rim sign describes relative hypoenhancement of the renal cortex and normal enhancement of the renal medulla on contrast-enhanced CT and MRI. This enhancement pattern can also be visualized using CEUS 2.
It is a typical finding of renal cortical necrosis that may occur in the setting...
Rhabdoid tumor of the kidney is a rare, highly aggressive malignancy of early childhood, closely related to atypical teratoid/rhabdoid tumors (AT/RT) of the brain (see rhabdoid tumors)
Rhabdoid tumors occur exclusively in children, with 60% occurring before the age of 1 year of ag...
Rhabdomyosarcomas of the genitourinary tract are uncommon tumors occurring in pelvic organs. It is a disease nearly exclusive to the pediatric population.
For a general discussion of this type of tumor, please refer to the article on rhabdomyosarcomas.
The peak incidence of tum...
Right iliac fossa mass is a common clinical presentation and has a range of differentials that need to be excluded. Radiology plays an important role in this differentiation.
The rim sign can be seen in association with chronic hydronephrosis.
In patients with chronic hydronephrosis, in all forms of contrast-enhanced imaging of the obstructed kidney, enhancement may occur in the residual, but markedly atrophic, renal parenchyma, surrounding the dilated calyces and ...
Risk factors for testicular germ cell tumors (GCT) include:
Caucasians at higher risk than African Americans (9:1)
10-40x increased risk
around 10% of all tumors are associated with undescended testis
higher risk if intra-abdominal testis compared with intra-inguinal
Robson staging of renal cell carcinoma (RCC) is simple but has largely been replaced by the TNM system (see renal cell cancer staging article). Robson staging revolves around the relationship to Gerota's fascia, involvement of renal vein and regional nodes.
stage I: limited to kidney
Sacral nerve stimulators are a form of neuromodulation therapy. They are used for urogenital disorders such as urge urinary incontinence and detrusor hyperactivity, and colorectal disorders such as chronic constipation refractory to conventional medical therapy, and fecal incontinence. There is ...
The salt and pepper sign is used to refer to a speckled appearance of tissue. It is used in many instances, but most commonly on MRI. Please note that pathologists also use the term.
Used to describe some highly vascular tumors which contain foci of hemo...
Sarcoidosis is a systemic inflammatory disease of unknown origin characterized by the formation of non-caseating granulomas. Virtually any organ system may be involved. Although less common than pulmonary and mediastinal disease, abdominal sarcoidosis can mimic more common infectious or neoplast...
Sarcomatoid renal cell carcinomas (sRCC) may develop when one of the more common histologic subtypes of renal cell carcinoma degenerates into a sarcoma.
On imaging, they are generally large masses, with irregular contours, and malignant-appearing, but do not have specific imaging features.
Schiller-Duval body is a perivascular structure that can be found in 50% of testicular yolk sac tumors also known as endodermal sinus tumors. If present it is considered pathognomonic.
A central vessel is surrounded by tumor cells, and the cell-vessel complex is contained in a cysti...
Schistosomiasis (also referred to as bilharzia or snail fever) is the result of infection by blood fluke (trematode worm) of the Schistosoma species.
Schistosomiasis is very common, affecting over 200 million people, with the vast majority (85%) in Africa. It is prevalent in tropi...
Bladder schistosomiasis, also known as bilharzia of the bladder, is a major health problem in developing parts of the world predisposing individuals to squamous cell carcinoma.
Schistosomiasis is very common, affecting over 200 million people, with the vast majority (85%) in Afric...
Sciatic hernia is a rare type of pelvic floor hernia, which occurs through either the greater or lesser sciatic foramina. It can contain variable structures.
curlicue ureter sign
Scleroderma, also known as systemic sclerosis, is an autoimmune connective tissue disorder characterized by multisystem fibrosis and soft tissue calcification. As such, it affects many separate organ systems, which are discussed separately:
musculoskeletal manifestations of scleroderma
Renal manifestations of scleroderma are common, affecting up to 25% of patients. Some patients (5-10%) can present with a scleroderma renal crisis (SRC). These patients have an abrupt onset of hypertension and acute renal failure 4.
For a general discussion of scleroderma, please refer to the ...
Scrotal cystoceles are a type of urinary bladder hernia, where the bladder herniates into the scrotum.
Scrotal sac will contain fluid. Emptying of a scrotal cystocele with voiding is an i...
Scrotal filariasis is a manifestation of filariasis and refers to scrotal involvement from parasitic nematodes of the superfamily Filarioidea.
Known disease of the tropics and subtropics and a cause of morbidity in Asia, Africa and the Western Pacific regions 2.
Scrotal haematoceles are collections of blood within the scrotal sac, but outside of the testis.
A haematocele normally results from trauma to the scrotum, or on occasion following surgery. Some think that a varicocele is a risk factor for developing a haematocele 4.
The scrotum and its content are subject to a number of infective processes including:
Scrotal pyoceles are purulent fluid collections in the scrotal sac, that generally occur in conjunction with epididymo-orchitis.
Scrotal pyoceles are typically a complication of epididymo-orchitis or testicular abscess but can also occur following trauma or surgery. The purulent flui...
Scrotal scintigraphy is a radio-isotope examination of the scrotal contents, primarily in patients presenting with scrotal pain.
Although, ultrasound remains the mainstay of scrotal imaging, scintigraphy can be used where the diagnosis is unclear, since ultrasound appearances for s...
Scrotal tunica cysts are paratesticular cystic lesions. They include:
tunica vaginalis cysts
tunica albuginea cysts
Typically seen as a simple appearing paratesticular cystic lesion not in the region of the epididymis.
Scrotoliths, also known as scrotal pearls, are benign incidental extra testicular macro-calcifications within the scrotum. They frequently occupy the potential space of the tunica vaginalis or sinus of the epididymis. They are usually of no clinical significance 1,2.
The scrotum (plural: scrota or scrotums) is a dual-chambered protuberance of skin and muscle that contains the testes, epididymides, and spermatic cord. It consists of two chambers separated by a septum. It is an extension of the perineum, and is located between the penis and anus.
Segmental renal hypoplasia, also known as the Ask-Upmark kidney, is a type of renal hypoplasia. It is often found in young females with severe hypertension. The etiology is unknown but has been postulated to be congenital or a sequelae of pyelonephritis. It is associated with severe juvenile hyp...
Segmental testicular infarctions are uncommon testicular lesions that usually result from arterial embolization or thrombosis (as opposed to testicular infarction from torsion, which may originate from venous occlusion).
The causes of a segmental testicular infarct include:
Selenium toxicity (rarely: hyperselenemia) is caused by excessive intake of the non-metallic element selenium (Se) in the diet.
It is less common than selenium deficiency. It is most frequently seen in some parts of India, in which there are naturally high levels of selenium in th...
The seminal vesicles are paired accessory sex glands of the male reproductive system. The seminal vesicle produces over two-thirds of the ejaculate and is very high in fructose.
The seminal vesicle is actually a 10-15 cm long tubular structure but is coiled tightly so it only me...
Seminal vesical abscesses are a complication of seminal vesiculitis.
The associated symptoms can be non-specific and are those typically associated with urinary tract infections:
perineal or abdominal pain
ejaculation of purulent mate...
Seminal vesicle cysts can be congenital or acquired.
Age of presentation of congenital cysts is during the period of greatest reproductive activity i.e in second and third decades of life, while acquired cysts are most often seen in the elderly age group.
Seminal vesiculitis is an uncommon entity characterized by inflammation of the seminal vesicles. It is most commonly infective in etiology and often associated with concurrent infection elsewhere in the male genital tract, forming part of the spectrum of male accessory gland inflammation 4. It i...
A septate uterus is a common type of congenital uterine anomaly, and it may lead to an increased rate of pregnancy loss. The main imaging differential diagnoses are arcuate uterus and bicornuate uterus.
It is considered the commonest uterine anomaly (accounts for ~55% of such anom...
Sertoli cell tumors of the testis are uncommon sex cord stromal tumors. They are less common than Leydig cell tumors of the testis.
May present in both pediatric and adult males, depending on the histologic subtype.
Testicular mass or firmness. May occasio...
Sex cord stromal tumors of the testis are uncommon testicular neoplasms. Although ~90% of these tumors are benign, they cannot be differentiated from testicular malignancies on imaging, and are therefore usually discovered after orchiectomy.
Leydig cell tumor of the testis (most common, ~30% ho...
Sexual differentiation refers to the embryological development of male and female phenotypes. Unlike sexual genotype which is determined at the time of fertilisation, the male and female phenotypes do not begin to differentiate substantially until the seventh week of gestation.
Sickle cell disease (SCD) (historically known as drepanocytosis) is a hereditary (autosomal recessive) condition resulting in the formation of abnormal hemoglobin (a hemoglobinopathy), which manifests as multisystem ischemia and infarction, as well as hemolytic anemia.
Hemoglobin SC (HbSC) dis...
Abdominal manifestations of sickle cell disease (SCD) are wide and can involve many organs.
For a general discussion, please refer to sickle cell disease.
may occur transiently with the sequestration syndrome, where rapid pooling of blood occurs in the spleen, resulting ...
A sigmoid kidney is an uncommon variant of the horseshoe kidney. Whereas the typical horseshoe kidney is fused only at the lower poles, in a sigmoid kidney both the upper and the lower poles are fused 1.
In the past 15 years sildenafil citrate-induced penile Doppler has emerged as a technique for evaluating erectile dysfunction. It has greater patient acceptability than the usual papaverine-induced color Doppler and is safer.
Sildenafil citrate is a popular vasodilator drug used in treatment of...
Small cell carcinomas of the bladder are rare bladder cancers with a poor prognosis. Its appearance overlaps other bladder cancers, in particular, urothelial/transitional cell carcinoma.
A very rare tumor, it has been estimated at <0.0001% of bladder cancers. It is thought to have...
The soft-tissue rim sign is used to distinguish a ureteric calculus from a phlebolith. The former appears as a calcific density with a surrounding rim of soft tissue which represents the edematous ureteric wall. Phleboliths on the other hand usually have imperceptible walls (although up to 8% ma...
Solitary filling defect with a ureter, as seen on conventional IVU or CT IVU has some differentials, including:
within the lumen
within the wall
transitional cell carcinoma (TCC)
When multiple fi...
SpaceOAR is a technique in which a physical space is created between the prostate gland and rectum for electron beam radiotherapy targeted to the prostate gland in cases of prostate cancer.
OAR stands for "organ at risk", and in cases of prostate cancer radiotherapy treatment the rectum is the...
The spaghetti sign may be seen in upper urinary tract bleeding.
It refers to the presence of a linear worm- or spaghetti-like filling defect within a contrast-opacified bladder 1,2. This linear filling defect represents blood clot extruded from the ureter and thereby molded into a tubular shape...
The spermatic cord is the tubular structure that suspends the testes and epididymis in the scrotum from the abdominal cavity.
The spermatic cord arises at the deep inguinal ring, passes through the inguinal canal and exits at the superficial inguinal ring into the scrotum...
Handy mnemonics to recall the contents of the spermatic cord are:
Papers Don't Contribute To A Good Specialist Level
3 arteries, 3 nerves, 3 fascias, 3 other things
Papers Don't Contribute To A Good Specialist Level
P: pampiniform plexus
D: ductus deferens
C: cremasteric artery
Spermatic cord hydrocele (SCH) refers to a loculated fluid collection along the spermatic cord. It is separated from, and located above, the testis and the epididymis.
It results from aberrant closure of the processus vaginalis.
There are two recognized subtypes
encysted hydrocele ...
Spermatic cord leiomyosarcomas are uncommon malignant paratesticular masses.
Accounts for ~10% of spermatic cord sarcomas. The average of a patient at presentation is 58 years old (although has been seen as young as 15 years old).
Patients may have left inguina...
Spermatic cord liposarcomas are the most common malignant tumor of the spermatic cord. Most present as painless, slow-growing masses and can be mistaken for inguinal hernias. They are usually well-differentiated and spread by local extension.
In a large population-based registry,...
Spermatoceles are a common type of extratesticular cyst, and represents cystic dilatation of tubules of the efferent ductules in the head of the epididymis.
Usually a painless, incidental finding but can present as a mass lesion if large 3.
Spermatoceles are u...
Sperm cell granuloma, also termed epididymitis nodosa, is a benign lesion that can occur in the scrotum. They can particularly occur in those with a prior vasectomy (occurs after vasectomy in up to 40% of patients 2).
It is considered a form of chronic epididymitis which occurs secon...
Spigelian-cryptorchidism syndrome is the association of Spigelian hernias and cryptorchidism in children.
It is reported that ~50% (range 28-75%) range of pediatric patients with Spigelian hernias will have ipsilateral cryptorchidism 1,2.
Along with Spigelian hernia and cryptorchi...
Spinning top urethra is non-obstructive posterior urethral dilatation seen on voiding cystourethrography, mainly in females. It was initially considered as an indicator of distal urethral narrowing/stenosis. However, it is now believed to be due to functional discoordinate voiding or bladder ins...
Splenogonadal fusion is a rare anomaly that occurs when there is congenital fusion between a portion of the spleen and a gonad or other mesonephric derivative.
Much more common in male patients (~95%), occurs most commonly on the left (98%) and usually involve the testis (95%). Ha...
The split bolus technique is a CT imaging investigation used in patients with hematuria aiming to put together, in a single image acquisition, both the nephrographic and renal excretory phases and thus reducing the radiation dose of the study. It is a CT protocol adopted for some institutions fo...
A spoke wheel pattern in renal imaging refers to a vascular appearance seen with certain renal tumors, typically seen in oncocytomas but can also be seen in renal cell carcinomas.
This appearance refers to a peripheral rim of vessels from which centripetal vessels converge centrally giving the...
Spontaneous retroperitoneal hemorrhage (SRH) is a distinctive clinical pathology of retroperitoneal bleeding without a preceding history of trauma.
For a broader discussion, including other etiologies, please refer to the parental article on retroperitoneal hemorrhage.
Spontaneous rupture of the renal pelvis, also known as pyelosinus backflow, is a rare complication that can occasionally occur with obstructive urolithiasis (usually in the distal third of the ureter) or occasionally infection 1. Leakage of urine can result in a urinoma, and there is an increase...
A spotted nephrogram is a descriptive term indicating an appearance of patchy, segmental and subsegmental renal parenchymal enhancement.
The pattern is indicative of focal areas of cortical ischemia or necrosis, as a result of small vessel occlusion. This abnormal perfusion pattern c...
Squamous cell carcinoma of the penis arises most commonly at the distal end of the penile urethra with local invasion of the glans.
In addition to TNM classification, the following staging is used:
stage I: confined to the glans or foreskin
stage II: invasion of penile shaft
Squamous cell carcinoma of the urinary bladder is rare and accounts for only ~3-8% 1,2 of all bladder cancers (90% are transitional/urothelial cell carcinomas) but nevertheless, SCC is the most common type of nontransitional cell carcinoma involving the bladder 2. SCC of the bladder is observed ...
Staghorn calculi, also sometimes called coral calculi, are renal calculi that obtain their characteristic shape by forming a cast of the renal pelvis and calyces, thus resembling the horns of a stag.
For a general discussion of renal calculi please refer to nephrolithiasis.
Steinstrasse [stīn′shtra-se] is the German word for "stone street", describing a possible complication of extracorporeal shock wave lithotripsy (ESWL) for urinary tract calculi, wherein a column of stone fragments forms that blocks the ureter.
Steinstrasse usually develops 1 day to 3...
The stipple sign refers to the pointillistic end-on appearance on intravenous pyelography or retrograde pyelography of contrast material tracking into the interstices of a papillary lesion. Because the majority of transitional cell carcinomas (TCC) have a papillary configuration, the presence of...
Strangury (also known as stranguria) describes a symptom of the unintentional agonising micturition of small volumes of urine or marked desire to do so, often without any urine passed. In many cases the bladder is empty or near empty.
It has been described as the urological form of tenesmus, an...
Striated nephrogram is a descriptive term indicating an appearance of alternating linear bands of high and low attenuation in a radial pattern extending through the corticomedullary layers of the kidney on iodine-based intravenous contrast enhanced imaging.
It is important to know that a simila...
The string of beads sign is the description typically given to the appearance of the renal artery in fibromuscular dysplasia (FMD) but may also be used to describe the appearance of splanchnic arteries in segmental arterial mediolysis (SAM). It refers to the appearance arising from the stenoses ...
A subcapsular perirenal hematoma is a form of perirenal hematoma where blood accumulates beneath the renal capsular margin.
It can arise from a number of causes
trauma, important in assessing renal trauma grading
post procedural, e.g. extracorporeal shock-wave lithotripsy (ESWL) 5,...
The sunburst sign refers to the appearance of arterial blush seen at selective arterial DSA of a renal angiomyolipoma.
Angiomyolipoma is a hypervascular renal mass that shows dense early arterial vascular network of tortuous irregular vessels with micro- or macroaneurysms.
The superficial perineal pouch is an anatomic space below the perineal membrane in the urogenital triangle of the perineum.
The superficial perineal pouch is inferior (superficial) to the perineal membrane in the urogenital triangle, anterior to the transverse line between the is...
The superior adrenal (suprarenal) arteries area a group of one of the three adrenal arteries that supply the adrenal gland. There are usually numerous small arteries arising from the inferior phrenic artery.
The superior suprarenal arteries arise from the inferior phrenic...
Supernumerary kidneys are a rare congenital anomaly of the urogenital system, where there are one or two accessory kidneys.
Less than 100 cases are documented.
Patients may be asymptomatic. If present symptoms range from fever, pain to abdominal mass. Thes...
Suprapubic cartilaginous cysts (SPCC) are rare cystic lesions arising from the symphysis pubis thought to be degenerative in origin. They have also been called retropubic or subpubic cysts.
In the small number of cases in the literature, all bar one patient, have been female. The ...
The supravesical fossae are concave depressions of peritoneum in the paravesical space bounded by the median umbilical fold and the medial umbilical folds. It partially overlies the inguinal (Hesselbach’s) triangle. The supravesical fossae are usually occupied by small bowel loops and the urinar...
Surgical hemostatic material is used to control bleeding intraoperatively and is hence frequently intentionally left in the operative bed, not to be confused with a gossypiboma which is caused by foreign material left behind in error. Its use has increased with the advent of minimally invasive s...
There are various classic surgical positions for patients to be placed in for procedures, which have been adopted/repurposed for interventional radiology and some diagnostic procedures:
reverse Trendelenburg position
lateral decubitus position