The 1-2-3 rule is a simple aide-mémoire describing the nomenclature of any small simple anechoic structure in the ovary on ultrasound:
<1 cm = follicle
1-2 cm = dominant follicle
>3 cm = cyst
The 2014 WHO classification is one of the classification systems for endometrial stromal tumors (EST).
Endometrial stromal tumors constitute <2% of all uterine tumors and <10% of uterine mesenchymal neoplasms 1.
Over the past four decades, EST classification has gone through various modificat...
Three-dimensional (3D) ultrasound is a technique that converts standard 2D grayscale ultrasound images into a volumetric dataset. The 3D image can then be reviewed retrospectively. The technique was developed for problem-solving (particularly in obstetric/gynecologic exams) and to potentially re...
The CT abdomen-pelvis protocol serves as an outline for an examination of the whole abdomen including the pelvis. It is one of the most common CT protocols for any clinical questions related to the abdomen and/or in routine and emergencies. It forms also an integral part of trauma and oncologic ...
Abdominal and pelvic anatomy encompasses the anatomy of all structures of the abdominal and pelvic cavities.
This anatomy section promotes the use of the Terminologia Anatomica, the international standard of anatomical nomenclature.
A mnemonic for causes of abdominal distension (6 Fs) is:
F: fulminant mass
The abdominal pain in pregnancy MRI protocol encompasses a set of MRI sequences for assessment of causes of non-traumatic abdominal pain in pregnancy.
Note: This article aims to frame a general concept of an MRI protocol for the assessment of the abdomen in pregnancy. Protocol specifics will va...
Abdominal surface anatomy can be described when viewed from in front of the abdomen in 2 ways:
divided into 9 regions by two vertical and two horizontal imaginary planes
divided into 4 quadrants by single vertical and horizontal imaginary planes
These regions and quadrants are of clinical imp...
Abnormally thickened endometrium on imaging may occur for a number of reasons which may be categorized based on whether or not they are related to pregnancy. Etiologies may also be classified based on whether the patient is premenopausal or postmenopausal.
Abscesses are focal confined collections of suppurative inflammatory material and can be thought of as having three components 1:
a central core consisting of necrotic inflammatory cells and local tissue
peripheral halo of viable neutrophils
surrounded by a 'capsule' with dilated blood vessel...
Accessory and cavitated uterine mass (ACUM) is a rare uterine anomaly comprised of an accessory uterus-like mass in the uterus along the wall but with no communication to the main uterus.
This pathology generally presents at a young age (before 30 years) with pelvic pain ...
Acute abdominal pain is a common acute presentation in clinical practice. It encompasses a very broad range of possible etiologies and diagnoses, and imaging is routinely employed as the primary investigative tool in its modern management.
A subgroup of patients with acute abdomina...
Acute appendicitis (plural: appendicitides) is an acute inflammation of the vermiform appendix. It is a very common condition in general radiology practice and is one of the main reasons for abdominal surgery in young patients. CT is the most sensitive modality to detect appendicitis.
Acute non-traumatic abdominal pain in pregnancy requires a considered imaging approach due to the increased risks of fetal demise associated with undiagnosed diseases such as perforated acute appendicitis. Ultrasound is the first-line modality due to its wide availability and ability to diagnose...
Acute pelvic pain is a common presenting symptom to the emergency department and radiologist. Pelvic ultrasound with transabdominal and endovaginal approaches is usually the first line imaging modality.
non-cyclical pain usually of more acute onset
pain of <3 months dura...
Adenocarcinoma of the endometrium is the commonest histological subtype of endometrial cancer and accounts for up to 90% of such cases 1.
serous type adenocarcinoma of the endometrium
clear cell type adenocarcinoma of the endometrium
Adenocarcinoma of the cervix is a histological subtype of carcinoma of the cervix.
Cervical adenocarcinoma is less common than squamous cell carcinomas (SCC) of the cervix, accounting for ~12.5% of all cervical cancer. Their proportionate prevalence is thought to be increasing an...
Adenoma malignum of the cervix, also referred to as minimal deviation carcinoma / minimal deviation adenocarcinoma, is considered a rare variant of cervical mucinous adenocarcinoma.
It is thought to represent ~1-3% of all cervical adenocarcinomas. It can present in a wide age gro...
Adenomatous endometrial hyperplasia is a type of endometrial hyperplasia.
The peak incidence is around 40-50 years of age.
Both endogenous and exogenous estrogen exposure are considered important factors in its etiology 1.
An adenomyoma is a focal region of adenomyosis resulting in a mass, which is difficult to distinguish from a uterine fibroid, although in general the degree to which the contour of the uterus is distorted is less marked in adenomyosis 2. Additionally, the 'mass' is poorly defined and blends with...
An adenomyomatous polyp of the endometrium is a rare form of endometrial polyp and comprises of a pedunculated lesion that contains smooth muscle in addition to the usual components of an endometrial polyp. On outer examination, they may be difficult to differentiate from ordinary endometrial po...
Adenomyosis (or uterine adenomyosis) is a common uterine condition of ectopic endometrial tissue in the myometrium, sometimes considered a spectrum of endometriosis. Although most commonly asymptomatic, it may present with menorrhagia and dysmenorrhea. Pelvic imaging (i.e. ultrasound, MRI) may s...
An adenomyotic cyst is an extremely rare variation of cystic adenomyosis. The lesion consists of a large hemorrhagic cyst, which is partly or entirely surrounded by a solid wall. It can be entirely within the myometrium, submucosal, or subserosal and frequently is associated with symptoms of men...
Adenosquamous cell carcinoma (ASC) of the cervix is a rare histological subtype of cervical carcinoma.
It has components of both cervical adenocarcinoma and cervical squamous cell carcinoma.
An adenosquamous histology appears to be an independent predictor of poor outcome...
Adenosquamous carcinoma of the endometrium is a rare histological subtype of endometrial cancer.
In general, it occurs in a slightly younger group when compared with pure adenocarcinoma of the endometrium 4.
It contains both malignant glandular and malignant squamous components. Adenosquamous...
Adnexa (single/plural) is a general term that refers to the accessory structures of an organ.
Adnexa have been described in relation to:
hair follicles, sweat glands, nails
structures in the mastoid (posterior) wall of the middle ear, e.g. mastoid antr...
The adnexa, or more formally the adnexa uteri, and also known as the uterine appendages, is a collective term for the:
Some texts also include the associated blood vessels, nerves and other supporting tissues in the definition. It is interesting to not...
Adult granulosa cell tumor of the ovary is a type of ovarian sex cord / stromal tumor. They are by far the most frequent subtype of granulosa cell tumors of the ovary (95%) and are commoner than the juvenile granulosa tumor of the ovary.
Approximately two-thirds of this subtype ar...
The biological/medical term agenesis (plural: ageneses) refers to failure of an organ to grow or develop during the embryological period.
corpus callosum agenesis
dental agenesis (anodontia)
Aggressive angiomyxomas are rare tumors that arise in the pelvis and typically cross the levator ani muscles. Despite its name, it is essentially a benign tumor and the term "aggressive" is due to a predilection for local recurrence. Only rarely does it metastasize.
It is seen pre...
Ampulla (plural: ampullae) is an anatomical term used for tubular structures with a short segmental bulbous dilatation:
ampulla (fallopian tube)
ampulla (lacrimal system)
ampulla (semicircular ducts)
ampulla of Vater
ampulla (ductus d...
The anatomy curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core anatomy knowledge for radiologists and imaging specialists.
Head and neck anatomy
Abdominal and pelvic anatomy
Androgen insensitivity syndrome (AIS), also known as the testicular feminization syndrome, results from end-organ resistance to androgens, particularly testosterone. AIS may be complete or incomplete with variable imaging findings.
The incidence may vary depending on whether it i...
Angiomyofibroblastomas are benign mesenchymal neoplasms usually found in the pelvis or perineum especially the vulva.
Angiomyofibroblastomas are uncommon tumors predominantly found in adult women usually between menarche and menopause. Approximately 10% of these tumors have been d...
Anorexia nervosa is a psychiatric disorder characterized by distorted self-perception of body weight leading to starvation, obsession with remaining underweight, and an excessive fear of gaining weight. One in five patients with anorexia dies due to complications of the disease.
Antral follicle count (AFC) or basal antral follicle count is a test performed to check a female individual's ovarian reserve.
A female is born with a lifetime supply of eggs and as she enters puberty these eggs develop. During and after puberty these follicles develop and are relea...
An arcuate uterus is a mildly variant shape of the uterus. It is technically one of the Müllerian duct anomalies, but is often classified as a normal variant. It is the uterine anomaly that is least commonly associated with reproductive failure. Arcuate uterus can be characterized with ultrasoun...
Asherman syndrome, also known as uterine synechiae, is a condition characterized by the formation of intrauterine adhesions, which are usually sequela from injury to the endometrium, and is often associated with infertility.
There is a tendency for the condition to develop soon af...
Bartholin gland abscess (maybe shortened to Bartholin abscess) is a complication that may result from an infected Bartholin gland cyst.
Abscesses are usually in a similar location to Bartholin gland cysts. Features of Bartholin gland abscess are otherwise similar to Bart...
Bartholin gland cysts (often shortened to Bartholin cysts) are cysts of the Bartholin gland, found in the posterolateral inferior third of the vagina and are associated with the labia majora.
Most patients are asymptomatic 4.
infection: may turn into Barth...
The Bartholin glands, also known as the greater vestibular glands (or vulvovaginal glands) are paired pea-sized structures, lying on either side of the vaginal opening, and are homologous to the bulbourethral (Cowper) glands in the male. They form part of the vulva.
These glands ...
Bartholin gland tumors represent neoplasms of the Bartholin glands.
squamous cell carcinoma of the Bartholin gland: tends to be the most common histological subtype
adenocarcinoma of the Bartholin gland
adenoid cystic carcinoma of the Bartholin gland
The beads-on-a-string sign is used to refer to the classic morphologic changes in the Fallopian tubes as a result of chronic salpingitis.
The "string" alludes to the notably thin salpingeal wall, while the hyperechoic mural nodules constitute the "beads" 1.
Benign metastasizing leiomyomas (or leiomyomata) are a rare non-malignant metastatic phenomenon that may be observed with a pelvic leiomyoma.
Women who have undergone hysterectomy for leiomyomas are most commonly affected.
Patients are usually asymptomatic ...
There are a number of benign metastasizing tumors:
benign metastasizing meningioma 1,2
benign metastasizing leiomyoma 3
primary adenoma of thyroid 4
giant cell tumor of bone 5
A bicornuate uterus is a type of uterine duplication anomaly. It can be classified as a class IV Mullerian duct anomaly.
Overall, congenital uterine anomalies occur in ~1.5% of females (range 0.1-3%). Bicornuate uteri are thought to represent ~25% (range 10-39%) of Mullerian duct ...
Body imaging is the term assigned to cross-sectional imaging of the body, which radiologically refers to the chest, abdomen and pelvis. It is often used by radiologists who report this region (sometimes known as body imagers/radiologists) to differentiate their primary area of interest from othe...
Body packing refers to the internal concealment of drugs within the gastrointestinal tract or other orifices. People who do this may be called body packers, (drug) mules, stuffers, couriers or swallowers. Drugs may be concealed within condoms, foil, latex or cellophane.
There is ...
Borderline ovarian serous cystadenomas lie in the intermediate range in the spectrum of ovarian serous tumors and represent approximately 15% of all serous tumors.
They present at a younger age group 1-2 than the more malignant serous cystadenocarcinomas with a peak age of present...
Brenner tumors are an uncommon surface epithelial tumor of the ovary. It was originally known as a transitional cell tumor due to its histological similarity to the urothelium. Brenner tumors account for ~3% of ovarian epithelial neoplasms. They can very rarely occur in other locations, includin...
The bridging vessel sign refers to an appearance of vessels coursing from the uterus into an adjoining pelvic mass (a vascular bridge). This sign helps to differentiate a pedunculated subserosal uterine leiomyoma from other juxtauterine masses of ovarian, adnexal or bowel origin.
Color and powe...
The broad ligaments (TA: ligamentum latum uteri or plica lata uteri 4) are the paired lateral folds of the parietal peritoneum which reflect over the upper genital tract in females.
The broad ligament extends from the lateral aspect of the uterus to the lateral pelvic wall and ca...
A mnemonic for the contents of the broad ligament is:
B: bundle (ovarian neurovascular bundle)
R: round ligament
O: ovarian ligament
A: artifacts (vestigial structures)
D: duct (oviduct)
Broad ligament leiomyomas are extra-uterine leiomyomas that occur in relation to the broad ligament.
Broad ligament leiomyomas are also referred as a type of parasitic leiomyomas 5.
While in most cases broad ligament leiomyomas are asymptomatic, patients ma...
The bulbs of the vestibule (also known as the vestibular, vestibulovaginal or clitoral bulbs) are conglomerations of erectile soft tissue, collectively homologous to the bulb of the penis. However unlike in the male, the developing bulb is bisected by the vaginal opening to form two halves.
CA-125 is a high-molecular-weight glycoprotein found on the surface of Mullerian and celomic epithelial-derived cell types and is the best known tumor marker for epithelial ovarian cancer 6. Importantly, it may also be elevated in several other conditions (see differential diagnosis section belo...
CA 27-29 is a tumor marker and is a soluble form of glycoprotein MUC1. It may be elevated in patients with breast cancer. Tumors of the colon, stomach, kidney, lung, ovary, pancreas, uterus, and liver may also raise CA 27-29 levels.
Certain non-malignant conditions are also associated with its ...
Cesarean section (also known as C-section, CS and C/S) is the most frequently done major abdominal surgery in females, performed to deliver a baby as an alternative to normal vaginal delivery 1.
Many forms of cesarean section have been described, but the most popular variat...
The canal of Nuck is an abnormal patent pouch of parietal peritoneum extending anteriorly from the round ligament of the uterus into the labia majora through the inguinal ring into the inguinal canal. Incomplete obliteration of this canal is known as a patent processus vaginalis and can result i...
Carcinoma of the cervix is a malignancy arising from the cervix. It is the third most common gynecologic malignancy (after endometrial and ovarian).
It typically presents in younger women with an average age of onset at around 45 years.
human papillomavirus (HPV) 1...
Carcinosarcomas are highly malignant biphasic tumors with both carcinomatous (epithelial) and sarcomatous (bone, cartilage, or skeletal muscle) components.
It can arise in many organs:
lung 5: pulmonary carcinosarcoma
esophagus 1: esophageal carcinosarcoma
genitourinary tract 2
Catamenial pneumothorax is a rare type of pneumothorax and is characterized by the recurrent accumulation of air in the thoracic space related to menstruation.
It may represent up to one-third of women with spontaneous pneumothoraces 1. Patient history may or may not be positive f...
Cellular angiofibromas are benign densely vascularized fibroblastic neoplasms usually found in the lower genital tract specifically vulva, vagina or perineum in women and the scrotum or groin in men.
Cellular angiofibromas are rare tumors found in the adult population. There is no...
Staging of cervical cancer can either be based on the TNM or FIGO system.
Revised FIGO staging of cervical carcinoma 2018 8
FIGO no longer includes Stage 0 (Tis)
I: confined to cervix uteri (extension to the corpus should be disregarded)
IA: invasive carcinoma only diagnosed by microscopy
In obstetric and gynecological imaging, the cervical length is defined as the distance between the internal cervical os and the external cervical os.
the cervical length is most accurately assessed on a transvaginal scan with an empty bladder
in a normal gr...
Cervical plicae palmatae are normal folds seen on the anterior and posterior walls of the cervical canal. They are often described as longitudinal ridges or oblique elevation.
Sometimes they are identified on MRI, and one must make sure not to misinterpret this finding as abnormal. Studies repo...
Cervical polyps are polypoid growths projecting into the cervical canal. They can be one of the most common causes of intermenstrual vaginal bleeding.
Most patients are perimenopausal at the time of presentation, especially in the 5th decade of life. They are the most common mass...
The term cervical stenosis can refer to:
stenosis of the uterine cervix
bony cervical canal stenosis (cervical spinal stenosis)
The cervix or uterine cervix is the lower constricted segment of the uterus providing the passage between the uterus proper and the vagina.
The cervix is somewhat conical in shape, with its truncated apex directed posteriorly and inferiorly. The inferior aspect of the cervix pro...
Cesarean section scar diverticulum is a form of outpouching located in the anterior lower uterine cavity at the site of cesarean section scar.
There is some similarity with the term cesarean scar niche.
The chevron sign refers to the appearance caused on axial pelvic MR images by posterior drooping of the posterolateral wall(s) of the upper third of the vagina, due to loss of integrity of the lateral level 1 endopelvic fascia.
Choriocarcinoma is an aggressive, highly vascular tumor. When it is associated with gestation, it is often considered part of the spectrum of gestational trophoblastic disease; it is then termed gestational choriocarcinoma. When it occurs in the absence of preceding gestation, it is termed non-g...
The staging system for choriocarcinoma (usually refers to uterine choriocarcinoma) is the FIGO staging system and is as follows 1:
stage I: disease limited to the uterus
stage II: disease out of the uterus but limited to the female genital tract
stage III: metastasis in the lung with or with...
There are many signs in radiology that are related to Christmas:
snowcap sign in avascular necrosis
in total anomalous pulmonary venous return
in pituitary macroadenomas
snowstorm appearance in complete hydatidiform and testicular microlithiasis
holly leaf sign in calcified pl...
Chronic pelvic pain is a common presenting symptom to primary care physicians and radiologists. Pelvic ultrasound with transabdominal and endovaginal approaches are usually the first-line imaging modality. MRI may be performed as an adjunct test.
non-cyclical pain (exclud...
Clear cell carcinoma of the cervix (CCCC) is a rare adenocarcinoma subtype of cervical cancer.
Due to association with diethylstilbestrol (DES) exposure in some patients, this subtype may have a younger age at presentation than other histological subtypes. This subtype can sometim...
Clear cell carcinoma (CCC) of the endometrium is an uncommon histological subtype of endometrial cancer. It only accounts for 1-5.5% of all endometrial carcinomas, and it is often associated with an aggressive clinical behavior and a poorer outcome 4-5. Only occasional case reports have describe...
Clear cell carcinoma of the ovary is a type of malignant ovarian epithelial tumor.
They represent ~2-5% of all ovarian carcinomas and ~3.7%-12% of epithelial ovarian neoplasms. The mean age at presentation is ~10 years younger than for other ovarian epithelial tumors (peaks ~55 ag...
The clitoris (plural: clitorides), the female homologue of the penis, and part of the female reproductive system, is situated at the anterior aspect of the labia minora. The clitoris, like the penis, is formed of a body and glans, formed respectively from the crura of the clitoris and the bulbs ...
Coexistent molar pregnancy refers to an extremely rare situation where there is a molar pregnancy occurring simultaneously with normal intra-uterine pregnancy.
The estimated incidence is at ~1:10,000-100,000 gestations (for a complete hydatidiform mole and a normal pregnancy) 2.
The cogwheel sign refers to an imaging appearance in pelvic imaging of thickening loops of the Fallopian tube seen on cross-section. There are infolding projections (sometimes looking like nodules) into the Fallopian tube lumen which is likened to that of a cogwheel. The sign is typically descri...
Colovaginal fistula is one form of genitourinary fistula. It is also sometimes classed under a type of gastro-intestinal fistula.
It refers to a communication between the colon (typically the rectum or sigmoid colon) with the vagina.
At times, specific terms are used dependent on th...
A simple mnemonic to recall a list of commonly calcifying metastases is:
B: breast cancer
T: papillary thyroid cancer
O: ovarian cancer (especially mucinous)
M: mucinous adenocarcinoma (especially colorectal carcinoma)
A mnemonic for the differential diagnosis of complex adnexal masses is:
C: cystadenoma/cystadenocarcinoma (serous and mucinous)
H: hemorrhagic ovarian cyst
E: ectopic pregnancy
A: abscess (tubo-ovarian)
H: hydrosalpinx/hematosalpinx (...
There are many classification systems for congenital utero-vaginal anomalies. These include:
Buttram and Gibbons classification 2
American Fertility Society (AFS) classification
Modified Rock and Adam - AFS classification
Modified Rock and Adam - AFS classification
This classification divid...
The corpus albicans is a fibrous scar that results from the involution of the corpus luteum if fertilisation does not occur. When seen on ultrasound, it is a small, lobulated echogenic intra-ovarian lesion.
History and etymology
It is Latin for "whitening body", after the white appearance of ...
Corpus luteal (CL) cysts are a type of functional ovarian cyst that results when a corpus luteum fails to regress following the release of an ovum. When associated with pregnancy, it is the most common pelvic mass encountered within the 1st trimester. There is also some overlap with the term "he...
Ruptured corpus luteal cysts are one of the commonest causes of spontaneous hemoperitoneum in a woman of reproductive age.
Presentation is variable, ranging from completely asymptomatic to severe abdominal pain due to peritoneal irritation.
The corpus luteum i...
The corpus luteum (plural: corpora lutea) is a temporary endocrine structure involved in ovulation and early pregnancy.
During ovulation, the primary follicle forms the secondary follicle and subsequently the mature vesicular follicle.
At ovulation the follicle ruptures expelling the ovum into...
Couvelaire uterus is a rare, non-fatal but severe complication of placental abruption.
Its incidence is ~5% in all cases of placental abruption 1.
It is caused by the seeping of blood/hematic infiltrate into the decidua basalis emerging as massive hematoma retroplace...
Cumulus oophorus refers to an appearance in the ovary in which multiple granulosa cells enlarge around a developing oocyte. These support cells ("cumulus cells") serve multiple functions in the maturation of the oocyte. They may occasionally be seen during a pelvic ultrasound, and should not be ...
Cystic adenomyosis is a rare variant of adenomyosis and is believed to be the result of repeated focal hemorrhages resulting in cystic spaces filled with altered blood products.
MRI is the most sensitive and specific imaging modality for this diagnosis and will demon...
Cystic degeneration is an uncommon type of degeneration that a uterine leiomyoma (fibroid) can undergo.
This type of degeneration is thought to represent ~4% of all types of uterine leiomyoma degeneration.
When the leiomyoma increases in size, the vascular supply to i...