Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

904 results found
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Lateral fossa

The lateral fossae are concave depressions of peritoneum in the paravesical space that lie between the lateral umbilical folds and the lateral parietal peritoneum. The lateral fossae are the smallest of the anterior paravesical fossae, and typically partially contain the cecum and/or sigmoid col...
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Lateral umbilical folds

The lateral umbilical folds are bilateral raised ridges of parietal peritoneum in the deep aspect of the anterior abdominal wall overlying the inferior epigastric vessels. The paired folds originate medial to the deep inguinal ring and end at the arcuate line on the posterior aspect of the anter...
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Lateroconal fascia

The lateroconal fascia is the peritoneal thickening which extends anterolaterally from the adjoining merging lateral borders of the anterior and posterior perirenal fasciae. Gross anatomy It increases progressively in length as it ranges distally. It traverses laterally in a transverse plane a...
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Layers of the scrotum (mnemonic)

A handy mnemonic to recall the layers of the scrotum is: Some Damn Englishman Called It The Testes Mnemonic S: skin D: dartos fascia and muscle E: external spermatic fascia C: cremasteric fascia I: internal spermatic fascia T: tunica vaginalis T: tunica albuginea
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Lead poisoning

Lead poisoning or plumbism is a multisystem condition due to the way in which lead interferes with the function of virtually every organ system. Plumbism most severely manifests due to its devastating effects on the CNS, but it also has important deleterious consequences on the skeletal, renal, ...
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Leiomyoma of the urinary bladder

Leiomyoma of the urinary bladder is a rare benign mesenchymal tumor of the bladder. The most common presenting complaints are urinary voiding symptoms such as obstruction and irritation.  These leiomyomas exhibit imaging characteristics on ultrasound, CT and MRI similar to those of uterine leio...
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Lentiform fork sign (basal ganglia)

The lentiform fork sign has been described on MRI and is seen as bilateral symmetrical hyperintensities in the basal ganglia surrounded by a hyperintense rim delineating the lentiform nucleus. It has been postulated to result from metabolic acidosis due to any cause 1, e.g. end stage renal dise...
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Leptospirosis

Leptospirosis results from infection of the zoonoses Leptospira spp. The condition can have multiorgan manifestations. Commonly affected organs include: lung: pulmonary leptospirosis liver: hepatic leptospirosis central nervous system: CNS leptospirosis skeletal muscle: muscular leptospirosi...
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Leukemia (testicular manifestations)

Leukemia testicular manifestations, or testicular leukemia, can be seen in patients during and after acute leukemia. The blood-testis barrier limits chemotherapy from reaching the testicle, and therefore the testicle can act as a harbor for leukemic cells. typically presents with painless testi...
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Leukoplakia of the urinary tract

Leukoplakia of the urinary tract is a squamous metaplasia of the urothelium (keratinization).  Clinical presentation Clinically the condition presents with hematuria in one-third of cases, dysuria, frequency and nocturia, and thus it can mimic cystitis. Passage of the desquamated keratinized e...
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Levator ani muscle

The levator ani muscle, also known as the muscular pelvic diaphragm, is the musculotendinous sheet that forms the majority of the pelvic floor, supports the pelvic viscera, and aids in urinary and fecal evacuation as well as maintaining continence. Gross anatomy The levator ani has three main ...
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Leydig cell tumor of the testis

A Leydig cell tumor of the testis is an uncommon testicular neoplasm. Its imaging appearance on ultrasound and MRI is nonspecific, but clinically it is associated with serum hormonal imbalance. Epidemiology 1-3% of all testicular tumors, but the most common sex-cord stromal tumor. Tend to be b...
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Lichen planus

Lichen planus refers to a dermatological condition that typically affects the skin, nails, oral cavity, genitals or perineum. Skin lesions are characterized by violaceous scaly pruritic plaque eruption while oral lesions are characterized by erosions and lace-like reticular plaques. It is a chr...
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Liddle syndrome

Liddle's syndrome is an autosomal dominant condition which inhibits the normal degradation of the ENaC sodium channel, resulting in findings that mimic Conn's syndrome (hyperaldosteronism); hypernatremia, hypokalemia and elevated serum bicarbonate. Typically patients are asymptomatic other than ...
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Lipomatosis

Lipomatosis is a condition where there is diffuse excessive fat deposition within the body. This can especially affect certain regions. neck and upper region of trunk Madelung disease mediastinal lipomatosis heart lipomatous hypertrophy of the interatrial septum lipomatous metaplasia of th...
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Lithium-induced renal disease

Lithium-induced renal disease is characterized by a progressive decline in renal function, evidenced by increasing serum creatinine and decreased creatinine clearance. The lithium salt causes direct injury to the renal tubules. The duration of lithium therapy increases the risk of progression to...
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Lobar nephronia

Lobar nephronia, also known as acute focal nephritis, refers to an intermediate stage between acute pyelonephritis and renal abscess, and is a focal region of interstitial nephritis.  It appears as a wedge of poorly perfused renal parenchyma, without a cortical rim sign. The condition is discu...
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Lobster claw sign (kidney)

Lobster claw sign refers to a urographic pattern of papillary excavation that may be seen with renal papillary necrosis. The lobster claw sign occurs when there is excavation around the edge of the papilla and the contrast material that extends into this excavated region looks like the "claws" ...
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Localized cystic renal disease

Localized cystic renal disease (LCRD), also known as localized cystic kidney disease, is an uncommon, non-familial, non-progressive disease characterized by clusters of cysts within the normal renal parenchyma. It can be confused with unilateral autosomal dominant polycystic kidney disease (ADPK...
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Loin pain hematuria syndrome

Loin pain hematuria syndrome is a rare disorder in which patients suffer episodes of severe unilateral or bilateral flank pain with microscopic or gross hematuria in the absence of renal pathology. Epidemiology Approximately 70% of patients are young females with a peak incidence in the third ...
Article

Loopogram

A loopogram is a fluoroscopic study of an ileal conduit, which is a type of urinary diversion. Terminology This procedure is also known is an ileal conduitogram, ileal loopography or ileostoureterography.  Procedure It is a retrograde study in which contrast is injected via the anterior abdo...
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Loop-to-loop colon

The loop-to-loop colon describes an abnormal colonic course associated with the absence of the left kidney from the renal fossa.  The transverse colon extends to the lateral margin of the abdominal wall and the descending colon courses medially to fill the renal fossa, resulting in a "looped" c...
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Lower urinary tract symptoms

Lower urinary tract symptoms (LUTS) are a constellation of symptoms including 1: poor stream despite straining hesitancy, frequency and incomplete emptying of the bladder terminal dribbling (at the end of the urinary stream) nocturia Although they are most frequently encountered in men with...
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Lowe syndrome

Lowe syndrome, also known as the oculocerebrorenal syndrome of Lowe, is a multisystem disorder characterized by anomalies primarily affecting the eyes, nervous system, and kidneys. Epidemiology It is an extremely rare, pan-ethnic disease, with an estimated prevalence in the general population ...
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Low signal intensity renal parenchyma

There are relatively few causes of low signal intensity renal parenchyma. Causes include: hemolysis paroxysmal nocturnal hemoglobinuria mechanical: malfunctioning prosthetic cardiac valve sickle cell disease infection hemorrhagic fever with renal syndrome (HFRS) vascular disease acute re...
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Lumbar hernia

Lumbar hernias are a rare form of posterior abdominal hernia.  Epidemiology Most common in patients aged between 50 and 70 years with a male predominance 1.  Clinical presentation Patients with lumbar hernias can present with a variety of symptoms, including a posterolateral mass, back pain,...
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Lying down adrenal sign

The lying down adrenal sign is a cross-sectional imaging sign of renal agenesis or ectopia in which the ipsilateral adrenal gland appears to be 'lying down' on the psoas muscle posteriorly. Due to the linear as opposed to Y-shaped configuration of the gland in such situations, it is also describ...
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Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare multi-system disorder that can occur either sporadically or in association with the tuberous sclerosis complex (TSC) and is often considered a forme fruste of TSC.​ Epidemiology It almost exclusively affects women of childbearing age 7. The estimated in...
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Macronodular adrenal hyperplasia

Macronodular adrenal hyperplasia refers to a morphological type of adrenal hyperplasia in which there is adrenal enlargement in the form of large distinct nodules. It can be congenital or acquired. A specific subtype under this entity is adrenocorticotropin independent macronodular adrenocortic...
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Maiden waist deformity

A maiden waist deformity is a name given to the appearance when there is medial deviation of both ureters. This typically occurs in retroperitoneal fibrosis. In this condition, there is medial indrawing of the ureters due to deposition of fibrous tissue in the retroperitoneum at the level of the...
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Mainzer-Saldino syndrome

Mainzer-Saldino syndrome (also known as conorenal syndrome (CRS)) is a rare condition and is one of the ciliopathies. It is due to mutations in the IFT140 gene, whose protein product is one of the six parts of the intraflagellar transport complex A. The syndrome's key characteristics are: phal...
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Malacoplakia of the urinary tract

Malacoplakia of the urinary tract is an uncommon chronic granulomatous inflammatory disease of the bladder wall. Malakoplakia (meaning "soft plaque") can affect any organ, but the urinary bladder is the most common location. Epidemiology Malacoplakia has a peak incidence in middle age and has ...
Article

Male pseudohermaphroditism

Male pseudohermaphroditism (MPH) is a variation of gender development.  Pathology Patients with male pseudohermaphroditism have 46 XY karyotype and may manifest as a female phenotype with various degrees of undervirilization secondary to partial androgen insensitivity.  Causes androgen insen...
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Male reproductive system

The male reproductive system (or tract) includes: penis testes epididymides ductus deferentia ejaculatory ducts seminal vesicles prostate bulbourethral glands It can be imaged using almost the entire range of imaging modalities but ultrasound and MRI are most often used (in part because...
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Male urethra

The male urethra is a fibromuscular tube that drains urine from the bladder. It has a longer, more complicated, course than the female urethra and is also more prone to pathology. Gross anatomy The male urethra measures, on average, 18-20 cm in length. It commences at the internal urethral ori...
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Male urethral segments (mnemonic)

A helpful mnemonic to remember the 4 segments of the male urethra from proximal to distal. Pet My Beautiful Pig Mnemonic P: prostatic M: membranous B: bulbous P: penile Posterior urethra equates to the prostatic and membranous urethras.  Anterior urethra equates to the bulbous and penile ...
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Management of Incidental Adrenal Masses: American College of Radiology white paper

The Management of Incidental Adrenal Masses revised in 2017 by the Adrenal Subcommittee of the Incidental Findings Committee of the American College of Radiology is an algorithm for the management of patients who are: adults (i.e. 18-year-old or over) asymptomatic for adrenal pathology referr...
Article

Manta ray sign (bladder)

The manta ray sign is a radiographic appearance in bladder exstrophy. It describes wide midline separation of the pubic bones simulating the appearance of a manta ray swimming towards you 1. The sacrum and iliac wings recall the manta ray’s head and body, with the widely spaced pubic rami formin...
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Mature metastasizing teratoma

A mature metastasizing teratoma is an uncommon complication of mature testicular teratomas, whereby distant metastatic deposits of histologically mature cells are encountered.  
Article

McCune-Albright syndrome

McCune-Albright syndrome (MAS) (also known as McCune-Albright-Sternberg syndrome) is a genetic disorder characterized by the association of: endocrinopathy: precocious puberty polyostotic fibrous dysplasia: more severe than in sporadic cases cutaneous pigmentation: coast of Maine 'cafe au lai...
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McDonald and McClellan's classification of crossed renal ectopias

McDonald and McClellan classified crossed renal ectopia into four types 1: bilateral crossed renal ectopia without fusion unilateral crossed renal ectopia bilaterally crossed renal ectopia: represents 90% of all crossed ectopias and includes crossed fused renal ectopia   crossed unfused rena...
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Medial fossa

The medial fossae are concave depressions of peritoneum in the paravesical space bounded by the medial umbilical folds and the lateral umbilical folds. The fossae are contained within the inguinal (Hesselbach’s) triangle. The right medial fossa typically partially contains the cecum and/or ileum...
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Medial umbilical folds

The medial umbilical folds are bilateral raised ridges of parietal peritoneum in the deep aspect of the anterior abdominal wall formed by the underlying medial umbilical ligaments running from the pelvis to the umbilicus. The medial umbilical ligaments are anatomical remnants of the obliterated ...
Article

Median umbilical fold

The median umbilical fold is a raised ridge of parietal peritoneum in the deep aspect of the anterior abdominal wall overlying the median umbilical ligament representing the anatomical remnant of the foetal urachus. It is one of the 5 umbilical folds and should not be confused with the bilateral...
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Medical devices in the abdomen and pelvis

Medical devices in the abdomen and pelvis are important to be recognized, just like medical devices of the chest. Often we ignore these devices, considering them to be incidental and non-pathological, however it is essential to be aware of potential complications. Gastrointestinal tubes stomac...
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Medullary cystic disease complex

Medullary cystic disease complex belongs to group of pediatric cystic renal diseases charaterised by progressive tubular atrophy with glomerulosclerosis (chronic tubulointerstitial nephritis) and multiple small medullary cysts.  Epidemiology There is no recognized gender predilection Clinical...
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Medullary nephrocalcinosis

Renal medullary nephrocalcinosis is the commonest form of nephrocalcinosis and refers to the deposition of calcium salts in the medulla of the kidney. Due to the concentrating effects of the loops of Henle, and the biochemical milieu of the medulla, compared to the cortex, it is 20 times more co...
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Medullary nephrocalcinosis (mnemonic)

A common mnemonic used to remember the etiology of medullary nephrocalcinosis is: HAM HOP Mnemonic H: hyperparathyroidism A: (renal tubular) acidosis M: medullary sponge kidney H: hypercalcemia/hypercalciuria O: oxalosis P: papillary necrosis See also renal papillary necrosis mnemonic ...
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Medullary sponge kidney

Medullary sponge kidney is a sporadic condition where the medullary and papillary portions of the collecting ducts are dysplastic and dilated and in most cases develop medullary nephrocalcinosis.  Epidemiology The incidence of medullary sponge kidney is estimated at ≈1:5000. Clinical presenta...
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Megacystis megaureter syndrome

Megacystis megaureter syndrome describes the radiologic appearance of a large capacity thin-walled bladder and massive primary vesicoureteral reflux. Pathology The pathophysiology of these massively dilated ureters and the large capacity bladder is the constant recycling of large volumes of r...
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Melioidosis

Melioidosis is an infectious disease caused by the bacterium Burkholderia pseudomallei (previously known as Pseudomonas pseudomallei) and is a multisystem disorder which may affect the lungs, brain, visceral organs, or musculoskeletal system. Epidemiology Melioidosis is a disease of the monsoo...
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Mesoblastic nephroma

Mesoblastic nephroma, also sometimes known as a congenital mesoblastic nephroma (CMN) or fetal renal hamartoma, is, in general, a benign renal tumor that typically occurs in utero or in infancy. Epidemiology It is the commonest neonatal renal tumor. Diagnosis is usually made in the antenatal p...
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Metallic ureteric stent

Metallic ureteric stents are a type of ureteric stent developed to offer improved symptomatic relief of obstruction when compared to polymeric (polyurethane) stents. They are often used in patients with chronic malignant ureteric obstructions who require placement of long-term ureteral stents to...
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Metanephric adenoma of the kidney

Metanephric adenoma (MA) of the kidney is a type of benign renal neoplasm.  Epidemiology While it can present at any age 6, the peak age of occurrence is thought to be around the 5th to 6th decades 2. There may be a 2:1 female preponderance 2.  Clinical presentation Metanephric adenoma is as...
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Metanephric blastema

Metanephric blastema (or metanephrogenic blastema) is one of the two embryological structure that gives rise to the kidney, the other one being the ureteric bud. Related pathology Persistent metanephric blastemas after 36 weeks of gestational age are called nephrogenic rests. They are associat...
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Metaplasia

Metaplasia is a general pathology term that refers to process when one cell type is replaced by another. It usually occurs in the context of a changed cellular environment to which the new cell type is better adapted 1. Examples include 2-5: Barrett esophagus: normal squamous epithelium replace...
Article

Metastases to testis

Metastases to testis are a very rare cause of a testicular mass and may be bilateral in up to 15% of patients.  Epidemiology Metastases to the testes are apparent in ~0.04% of autopsy studies in patients with known malignancy. The average age is 57 years, much older than the primary age for pr...
Article

Microlithiasis (disambiguation)

Microlithiasis (rare plural: microlithiases) merely means very small stones and may refer to: alveolar microlithiasis biliary microlithiasis calyceal microlithiasis testicular microlithiasis
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Middle adrenal artery

The middle adrenal (suprarenal) artery is one of the three adrenal arteries that supply the adrenal gland. Gross Anatomy Origin The middle suprarenal arteries arise from the aorta on each side between the inferior phrenic artery and the renal artery. They run laterally across the diaphragmati...
Article

Milk-alkali syndrome

Milk-alkali syndrome is the combination of: hypercalcemia renal failure metabolic alkalosis It is due to a large amount of calcium and alkali being ingested (e.g. milk and antacids for peptic ulcer disease treatment or calcium carbonate for osteoporosis). It is a cause of medullary nephrocal...
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Milk of calcium (disambiguation)

The term milk of calcium (MOC) is given to dependent, sedimented calcification within a cystic structure or hollow organ. This sort of colloidal calcium suspension layering can occur in various regions: renal: milk of calcium in renal cyst (most common) breast: milk of calcium in breast cyst ...
Article

Mixed gonadal dysgenesis

Mixed gonadal dysgenesis (MGD) is a type of gonadal dysgenesis characterized by gonadal asymmetry, and/or sex chromosomal mosaicism, as well as retained Müllerian ducts. Pathology Depending on the chromosomal composition, patients may have testes and/or streak gonads. Genetics affected indiv...
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Mixed epithelial and stromal tumor

Mixed epithelial and stromal tumors (MEST) are a family of uncommon renal neoplasms in adults in a spectrum ranging from predominantly cystic (adult cystic nephroma) to more solid tumors.  Epidemiology There is a female preponderance 10:1 1 with tumors occurring predominantly in middle-aged pe...
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Molar tooth sign (abdomen)

The abdominal molar tooth sign refers to the appearance of contrast media which has spilled out of the urinary bladder on CT cystography after extraperitoneal bladder rupture. Contrast flows out of the ruptured bladder, occupying the preperitoneal cavum Retzii and surrounds the bladder in the s...
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Molar tooth sign (disambiguation)

The molar tooth sign may refer to: molar tooth sign (CNS) molar tooth sign (abdomen)
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Mons pubis

The mons pubis (plural: montes pubis) refers to the rounded protuberant skin-covered soft tissue overlying the symphysis pubis (in both sexes). It is most prominent in adult females. In females it forms the most superior part of the vulva and it is also called the mons Veneris (plural: montes V...
Article

Moth eaten calyces

Moth eaten calyx refers to the ragged, feathery calyceal outline due to irregular erosions of the calyx. It is one of the earliest excretory urographic appearance of genitourinary tuberculosis.  Pathology This appearance is due to necrotizing papillitis, which may further progress to form medu...
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MR defecating proctography

MR defecography is a dynamic study for evaluation of the pelvic floor and pelvic organ prolapse. Phases There are four phases of evaluation: rest squeeze strain (Valsalva) defecation/evacuation Method of evaluation Many variations in the techniques described below exist. Patient prepara...
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MRI targeted prostate biopsy

MRI targeted prostate biopsy refers to an imaging targeted technique rather than the traditional systematic approach of a prostate biopsy after respective imaging with multiparametric MRI (mpMRI) of the prostate. As a consequence of the recent advances of multiparametric MRI (mpMRI) of the pros...
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MR spectroscopy in prostate cancer

MR spectroscopy is a promising development in the radiological evaluation of possible prostate malignancy.  The MR spectroscopic evaluation is mainly based on the choline peak elevation and choline-creatinine ratios. Choline/creatine to citrate ratios: > 0.5: suspicious > 0.8: very suspiciou...
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Mulberry stone

A mulberry stone is one of the types of urinary tract stones. It is formed of calcium oxalate dihydrate. It can be considered as a subset of a jackstone calculus which has a spiked appearance. When the stone has less well-developed spikes, it may appear to have a mamillated appearance, hence it ...
Article

Müllerian duct cyst

A Müllerian duct cyst is a cyst that arises from remnants of the Müllerian duct and is one of the midline cystic masses in the male pelvis.  Epidemiology Müllerian duct cysts usually occur in the 3rd and 4th decades of life (whereas prostatic utricle cysts are most often detected in the 1st an...
Article

Multicystic dysplastic kidney

Multicystic dysplastic kidney (MCDK) is a type of non-heritable pediatric cystic renal disease. It results in multiple cysts being formed in utero in the affected kidney. Epidemiology Unilateral incidence is estimated at 1:2500-4000. There may be a predisposition for the left kidney, a slightl...
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Multicystic mesothelioma

Multicystic mesotheliomas are a rare benign subtype of mesothelioma.  Terminology The nomenclature for this condition can be confusing due to the use of multiple interchangeable different synonyms that put it together with the peritoneal inclusion cysts. Although there is still some debate on ...
Article

Multilocular cystic renal neoplasm of low malignant potential

Multilocular cystic renal neoplasm of low malignant potential is a low-grade adult renal tumor composed entirely of numerous cysts. The entity was previously known as multilocular cystic renal cell carcinoma, which usually had clear cell morphology, but was redefined in the 2016 WHO classificati...
Article

Multiparametric MRI (mpMRI) of the prostate

Multiparametric MRI (mpMRI) of the prostate combines anatomic information from T1-weighted and T2-weighted sequences with functional information from diffusion-weighted imaging (DWI) and dynamic contrast enhancement (DCE). In some situations other techniques like MR spectroscopy (MRS) may also b...
Article

Multiple endocrine neoplasia syndromes

Multiple endocrine neoplasia (MEN) syndromes are a collection of syndromes characterized by the presence of, as the name would suggest, multiple endocrine tumors. They are autosomal dominant in inheritance. MEN1 (Wermer syndrome) MEN2 (multiple endocrine adenomatosis) MEN2a (Sipple syndrome) ...
Article

Multiple endocrine neoplasia type II

Multiple endocrine neoplasia type II (MEN2) is also known as mucosal neuroma syndrome or multiple endocrine adenomatosis. It is a collection of syndromes characterized by the presence of multiple endocrine tumors.  They are autosomal dominant in inheritance, and share medullary thyroid carcinom...
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Multiple endocrine neoplasia type IIb

Multiple endocrine neoplasia (MEN) type IIb, also known as MEN type 3 (MEN3) 3 or mucosal neuroma syndrome 2, accounts for only 5% cases of MEN2 and is characterized by: pheochromocytoma(s): in 50% of patients, often bilateral, and can be extra-adrenal medullary thyroid cancer: 100% of patient...
Article

Multiple filling defects of the ureter (differential)

Multiple filling defects within a ureter, as seen on conventional IVU or CT IVU, have a relatively small differential including: spreading or multifocal transitional cell carcinoma (TCC) vascular indentations multiple ureteral stones (steinstrasse) blood clots ureteritis cystica Stevens-Jo...
Article

Musculus compressor nuda

Musculus compressor nuda is a small striated musculotendinous sling of the bulbocavernosus muscle, which extends from the anterior and lateral surfaces of the proximal bulbous urethra. Musculus compressor nuda causes the proximal bulbous urethra to form a symmetric convex cone shape where the t...
Article

N-acetylcysteine

N-acetylcysteine (NAC) if often used as a prophylaxis against contrast-induced nephropathy. Protocols for administration vary widely from institution to institution and the true efficacy is still controversial. A typical protocol is [1-2]: 600 mg acetylcysteine twice daily on the day of the ex...
Article

Neonatal hydronephrosis

Neonatal hydronephrosis is most commonly diagnosed antenatally as fetal pylectasis, and in the majority of cases is due to pelvi-ureteric junction (PUJ) obstruction.   Pathology Etiology pelvi-ureteric junction (PUJ) obstruction (50% of cases 1,6) vesicoureteric reflux (~20% of cases 5) pos...
Article

Nephroblastomatosis

Nephroblastomatosis refers to diffuse or multifocal involvement of the kidneys with nephrogenic rests (persistent metanephric blastema). Epidemiology Nephrogenic rests are found incidentally in 1% of infants. Pathology Nephrogenic rests are foci of metanephric blastema that persist beyond 36...
Article

Nephrocalcinosis

Nephrocalcinosis, previous known as Anderson-Carr kidney or Albright calcinosis, refers to the deposition of calcium salts in the parenchyma of the kidney. It is divided into several types, with differing etiologies, based on the distribution: medullary nephrocalcinosis: 95% cortical nephrocal...
Article

Nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF), also known as nephrogenic fibrosing dermopathy, is a complication of gadolinium-based contrast agents used in MRI. It is characterized by "firm, erythematous, and indurated plaques of the skin associated with subcutaneous edema" 1. Eventually, flexure contra...
Article

Nephroptosis

Nephroptosis, also known as floating/wandering kidney or ren mobilis, refers to the descent of the kidney more than 5 cm or two vertebral bodies when the patient moves from a supine to upright position during IVU 1,2. Displacement can also occur medially across the midline, so-called medial nep...
Article

Nephrostomy

Nephrostomy is a common urologic or interventional radiology procedure in which a tube/catheter is introduced into the renal collecting system (usually the renal pelvis). Nephrostomies can either be "open" nephrostomy: after a urological surgical procedure, such as a UPJ stone removal these t...
Article

Nephrotic syndrome

Nephrotic syndrome results from loss of plasma proteins in the urine and characterized by hypoalbuminemia, hyperalbuminuria, hyperlipidemia, and edema. It may be caused by primary (idiopathic) renal disease or by a variety of secondary causes. Clinical presentation Patients present with marked...
Article

Neuroblastoma

Neuroblastomas are tumors of neuroblastic origin. Although they may occur anywhere along the sympathetic chain, the vast majority arise from the adrenal gland. They represent the most common extracranial solid childhood malignancy and are the third commonest childhood tumor after leukemia and b...
Article

Neuroblastoma (staging)

There are two methods of neuroblastoma staging, one that is based on post-operative patients (INSS) and one developed for pre-treatment patients (INRGSS). Staging International Neuroblastoma Staging System (INSS) This staging system is for post-operative patients and mainly for prognosis 1: ...
Article

Neuroblastoma vs Wilms tumor

Both neuroblastoma and Wilms tumor occur in early childhood and typically present as large abdominal masses closely related to the kidneys. Distinguishing between the two is important, and a number of features are helpful. Neuroblastoma calcification very common: 90% encases vascular structur...
Article

Neurocristopathy syndromes

Neurocristopathy syndromes encompasses a group of conditions united by abnormal migration, differentiation, division or survival of neural crest cells 1. Examples include: Waardenburg-Shah syndrome Haddad syndrome MEN IIa neurofibromatosis type I (NF1) Sturge-Weber syndrome Bamforth-Lazar...

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