MRI in pelvic inflammatory disease: a pictorialreview

Ferenc Czeyda-Pommersheim , Bobby Kalb, James Costello, Joy Liau,

Arash Meshksar, Hina Arif Tiwari, Diego Martin

Department of Medical Imaging, University of Arizona, 1501 N Campbell Ave., PO Box 245067, Tucson, AZ 85724, USA

Abstract

Pelvic inflammatory disease (PID) is an ascendinginfection of the female genital tract caused by the spreadof bacteria from the vagina to the pelvic reproductiveorgans and occasionally the peritoneum. The mostcommon causative organisms are sexually transmitted.PID is a significant source of morbidity among repro-ductive age women both as a cause of abdominal painand as a common cause of infertility. Its clinical pre-sentation is often nonspecific, and the correct diagnosismay first come to light based on the results of imagingstudies. MRI is well suited for the evaluation of PID andits complications due to its superior soft tissue contrastand high sensitivity for inflammation. MRI findings inacute PID include cervicitis, endometritis, salpingitis/oophoritis, and inflammation in the pelvic soft tissues.Acute complications include pyosalpinx, tuboovarianabscess, peritonitis, and perihepatitis. Hydrosalpinx,pelvic inclusion cysts and ureteral obstruction may de-velop as chronic sequela of PID. The pathophysiology,classification, treatment, and prognosis of PID are re-viewed, followed by case examples of the appearance ofacute and subclinical PID on MR images.

Key words: Pelvic inflammatory disease—Tuboovarianabscess—Salpingitis—Endometritis—Fitz-Hugh–Curtissyndrome

Pelvic inflammatory disease (PID) is a contiguousascending infection of the female genital tract caused bythe spread of microorganisms from the vagina to the

cervix and the internal genitalia. PID is a common causeof abdominal pain among women of reproductive ageand may result in significant long-term morbidity, mostoften in the form of tubal infertility and chronic pelvicpain. Although the incidence of PID has decreased in thepast decade, its public health and financial impact re-mains profound. In the United States, the number ofinitial physician visits for PID among women15–44 years old ranged from 88,000 to more than160,000 per year between 2004 and 2013, with an esti-mated annual cost of treatment of $1.88 billion in 1998,the most recent year a cost estimate is available [1, 2].

The continuum of infection in PID includes endo-cervicitis, endometritis, salpingitis, and in some casesperitonitis. The clinical manifestations are varied andoften subtle or nonspecific, making PID a diagnosticchallenge even for experienced clinicians. Althoughimaging is not a necessary component of diagnosingPID, many women with symptomatic PID initially pre-sent in the urgent care and emergency room setting whereimaging is often used in the initial workup of these pa-tients, especially to exclude other causes of pain. Ultra-sound is the most common first-line modality for theimaging of acute pelvic pain, and is an excellent study forcertain complications of PID such as abscess. However,ultrasound is insensitive to most presentations of PID,demonstrating no specific imaging features to suggest thediagnosis. Magnetic resonance imaging (MRI) is wellsuited for the imaging evaluation of PID and its com-plications due to its high sensitivity to inflammation andexcellent soft-tissue contrast. There is increasing evidencefor the utility of MRI in the setting of acute abdomi-nopelvic pain, with rapid, noncontrast protocols that arerobust in freely breathing patients with the ability todiagnose a wide range of acute pathologies [3–7].

In this study, we review the pathophysiology, classi-fication, and treatment of PID, followed by case exam-ples of the MRI appearance of acute and subclinical PIDand its complications.

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Correspondence to: Ferenc Czeyda-Pommersheim; email: pommersheimf@radiology.arizona.edu

ª Springer Science+Business Media New York 2016

Published online: 8 December 2016AbdominalRadiology

Abdom Radiol (2017) 42:935–950

DOI: 10.1007/s00261-016-1004-4

Classification and pathogenesis

PID is classified according to clinical symptoms andetiologic agents as acute, subclinical, or chronic PID.Acute PID signifies the presence of infection with recent(less than 30 days) onset of clinical symptoms. Subclini-cal PID manifests with long-term reproductive compli-cations due to asymptomatic infection of the uppergenital tract by the same pathogens as acute PID andoccurs in women with a previous or undiagnosed episodeof acute PID. The pathogenesis of subclinical PID isrelated to the effects of the normal immune response toupper genital tract infection which result in structuraland functional damage to the fallopian tubes [8]. Patientsmay have only sequela of prior inflammation and noactive disease, although many asymptomatic patientshave shown evidence of active endometritis on endome-trial biopsy [8]. Chronic PID represents a small minorityof cases and is the result of longstanding infection byMycobacterium tuberculosis and Actinomyces species.

Over 85% of acute and subclinical PID is caused bysexually transmitted diseases, the majority by Chlamydiatrachomatis and Neisseria gonorrheae [8–10]. Risk fac-tors include young age, cigarette smoking, sexual activitywith multiple partners, and bacterial vaginosis. In heal-thy women, the cervical mucus plug and the normalvaginal bacterial flora protect against the spread of pa-thogens across the cervix. Bacterial vaginosis is thoughtto predispose to PID through disrupting the normalprotective vaginal microflora and allowing the causativeorganism to colonize the vagina, with eventual spread tothe cervix and endometrium [10].

Less than 15% of cases of acute and subclinical PIDare caused by non-sexually transmitted pathogens suchas E. coli or Streptococcus [8]. Many of these are relatedto the use of intrauterine contraceptive devices whichmay become seeded with skin or gut bacteria.

Complications of PID may occur at any involvedanatomic level from the cervix to the peritoneum. Severeacute complications include tubo-ovarian/pelvic abscess,and peritonitis. Salpingitis may lead to tubal scarring andcause infertility or chronic pelvic pain. Post-inflammatorystrictures in the fallopian tubes put the patient at sub-stantially increased risk of ectopic pregnancy and infer-tility. Regardless of microbial cause, a history of PIDmaydouble the risk of infertility compared to women withoutprior PID [11]. Peritoneal inflammation, depending on thesite of involvement can also cause peritoneal bands, scar-ring, and strictures in the adjacent viscera and lead to ur-eteral obstruction or small bowel obstruction.

Post-inflammatory adhesions or fibrous bands devel-op in the abdomen and pelvis as a result of chronicinflammation. Adhesions may cause bowel obstruction,contribute to the development of inclusion cysts and maylead to chronic pelvic pain. Inclusion cysts form due tobenign, reactive proliferation of the peritoneal mesothe-

lium in the setting of chronic inflammation of any cause.Their development requires the presence of an activeovary in addition to peritoneal adhesions. Inclusion cystsare therefore almost exclusively observed in pre-menopausal women [12].

As the endometrial and peritoneal cavities are in di-rect communication through the fallopian tubes, anyinfection in the endometrium has a direct route to spreadto the peritoneum and potentially the upper abdomen.Fitz-Hugh–Curtis syndrome (FHC) develops when pel-vic infection spreads along the peritoneal surfaces to thehepatic capsule and causes upper abdominal peritonitisand perihepatitis. While originally thought to occur onlyin patients with gonorrheal PID, other pathogens caus-ing PID have also been shown to cause FHC [13].

Clinical presentation

Symptoms of acute PID are often nonspecific which cansubstantially delay diagnosis [9, 10]. Patients most oftenhave bilateral lower abdominal and pelvic pain, vaginaldischarge or spotting, and dyspareunia. Patients withFHC present with upper abdominal pain or right upperquadrant pain caused by perihepatitis due to irritation ofthe peritoneum and liver capsule. Constitutional symp-toms such as fever and malaise sometimes occur but areusually not the main clinical feature [8]. Gonococcalinfection tends to produce more severe symptomsincluding severe abdominal pain and high fever.

Subclinical PID does not produce clinical symptomsand usually presents as infertility. Up to 80% of womenwith infertility related to subclinical PID report no his-tory of clinically symptomatic acute PID or report ahistory of vague, nonspecific symptoms that have re-solved by the time the patient comes to clinical attention,underscoring the importance of being mindful of sub-clinical chronic infection in women with difficulty con-ceiving even in the absence of a known history or recentrisk factors of PID [4].

Patients with chronic PID usually have indolentgeneralized symptoms such as chronic low-grade fever,weight loss, and mild chronic abdominal pain.

Physical examination findings in acute PID are oftennonspecific and widely variable depending on the extentand severity of inflammation, and may range from lowerabdominal pain severe enough to mimic appendicitis toright upper quadrant pain in cases of peri-hepatitis thatmimics acute liver or biliary pathology. Cervical friabil-ity, discharge and cervical motion tenderness are usuallypresent on pelvic examination. The most widely availablelaboratory tests are rarely helpful in establishing adiagnosis. For instance, serum white blood cell count iselevated in less than 50% of patients. Tests that providedefinitive diagnosis including endometrial biopsy anddiagnostic laparoscopy are invasive, time-consuming,and are not practical in the acute care setting [14].

936 F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review

Diagnosis

There is no single imaging or laboratory test, presentingsymptom or physical examination finding highly specificfor PID. PID is therefore usually a clinical diagnosis, andrequires synthesis of all available clinical informationand laboratory results. The differential diagnosis isbroad and depending on the acuity of symptoms includesconditions ranging from acute appendicitis to irrita-ble bowel syndrome.

PID needs to be considered in any reproductive agewoman presenting with acute or chronic abdominal pain.According to CDC guidelines, a presumptive clinicaldiagnosis of PID can be made if one or more of thefollowing three minimal criteria are present in a sexuallyactive reproductive age woman who is experiencing pel-vic or lower abdominal pain with no alternative diag-nosis: cervical motion tenderness, uterine tenderness, oradnexal tenderness. The presence of one or more of thefollowing additional criteria can enhance the sensitivityof diagnosis: oral temperature >101�F (>38.3�C),abnormal cervical mucopurulent discharge or cervicalfriability, presence of abundant numbers of WBC onsaline microscopy of vaginal fluid, elevated erythrocytesedimentation rate, elevated C-reactive protein, andlaboratory documentation of cervical infection with N.gonorrhoeae or C. trachomatis [15]. These criteria, how-ever, even in combination, are nonspecific and evenexperienced practitioners often have limited accuracy indiagnosing PID.

Treatment

Women with uncomplicated PID are treated with broadspectrum antibiotics that provide empiric coverage of themost common causative agents. The length and route of

therapy are dependent on the extent of infection andcomorbidities. Patients who are severely ill or have sig-nificant comorbidities may need to be hospitalized forintravenous antibiotics and supportive care. Patientswith pelvic abscess and tubo-ovarian abscess often re-quire surgical or percutaneous intervention [10]. Com-plications such as ureteral obstruction or bowelobstruction may also require surgery.

Imaging

While PID is typically a clinical diagnosis, imaging playsan important role in patients who already carry a diag-nosis to identify complications that may require hospi-talization for invasive therapy [10]. When the diagnosisof PID is uncertain, or the patient presents to theemergency department with acute abdominal pain orother nonspecific symptoms, patients with PID willcommonly undergo imaging to exclude other patholo-gies, such as appendicitis or diverticulitis. The radiologistis therefore often in a position to suggest the correctdiagnosis when PID is not clinically suspected.

The most commonly used imaging modalities in theemergency setting, computed tomography (CT), andultrasound (US) have limited ability to detect earlierstage infection of cervicitis and endometritis [16, 17].Cervical, endometrial, or ovarian edema is among thefirst imaging manifestations of acute PID and causeenlargement of the cervix, ovaries, and the uterus withsigns of increased vascular flow such as hyperenhance-ment on CT, increased opacification with color onDoppler ultrasound [18]. CT or ultrasound is rarely ableto demonstrate edema if imaging signs such as organenlargement or hyperemia are subtle or absent. Com-plications of PID such as a tuboovarian abscess orhydrosalpinx from chronic fallopian tube scarring are

Table 1. MRI technique-pelvic inflammatory disease

Parameter Single-shot fastspin-echo

Single-shot fast

spin-echo w/FS

Single-shot fastspin-echo

3D T2wturbo

spin-echo

T1win- and opposed-phase spoiledgradient echo

T1w 3Dspoiled

gradient-echo

T1w 3Dspoiled

gradient-echo,post-contrast

Plane Axial Axial Sagittalb Axial Axial Axial AxialBreath-hold No No No No Yes Yes YesFat Saturation No SPAIR No No No Yes YesField-of-view (mm) 400 9 375 400 9 375 250 9 225 256 9 230 400 9 375 400 9 375 400 9 375Matrix 256 9 224 256 9 224 256 9 224 256 9 230 320 9 256 288 9 220 288 9 220Slices 35 35 25 192 35 88 88Thickness (mm) 7.0 7.0 7.0 1.0 6.0 3.0 3.0Gap (mm) 0.7 0.7 0.7 0.0 1.5 N/A N/ATR (ms) 1500 1500 1500 1200 150 3.8 3.8TE (ms) 85 85 85 105 2.2 and 4.5 2.1 2.1Flip angle (deg) 150 150 150 Variable 70 10 10PAT factora 2 2 3 2 2 2 2Clinical utility Anatomy; fluid

containingstructures

Inflammation;identify fattystructures

Anatomy;fluid containingstructures

Anatomy,especiallyof smallerstructures

Evaluate fatand iron/air

Blood products,hemorrhagiccysts orendometriomas

Enhancingneoplasms

a Parallel acquisition techniqueb Sagittal coverage from femoral head to femoral head

F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review 937

well seen by both CT and US. However, when suchcomplications are present, the patient already requiresinvasive treatment or is at significantly increased risk ofinfertility, both preventable if the diagnosis is made at anearlier stage of infection.

MRI is becoming more commonly used in the eval-uation of patients with acute and chronic abdominalpain, and has been shown to be an effective first line

modality for imaging of patients with acute abdominalpain and superior to sonography in the diagnosis of theentire spectrum of PID [4, 19, 20]. Unlike CT, MRI doesnot expose the patient to ionizing radiation, and unlikeUS, it provides detailed evaluation of the entire abdomenand pelvis. Compared to both CT and US, MRI providessuperior soft tissue contrast and is highly sensitive toeven very mild soft-tissue inflammation.

Fig. 1. Cervicitis and endometritis in a 23-year-old womanpresented to the ER with pelvic pain and dysuria. Cervical examshowed edema and a friable cervix. T2W FS axial images at thelevel of the cervix (A) and the uterine body (B) show markedcervical (arrow) and uterine myometrial (arrowhead) edema.

Corresponding slices on T1 FS images before (C, D) and after(E, F) contrast show marked hyperenhancement of the samestructures in keeping with cervicitis and endometrial/myometrialinflammation. The fallopian tubes were not seen, a normalfinding unless hydrosalpinx is present.

938 F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review

MRI technique

MRI protocols for use in the emergency departmentshould be streamlined, rapid, and robust even in patientswho are unable to breath-hold (Table 1). Optimized fatsuppression techniques are critical to maintain high sen-sitivity for disease detection and are especially importantfor the detection of PID. T2-weighted (T2W) imagingrepresents the core MR sequences required for the evalu-ation of acute pelvic pain. T2W provides fluid sensitiveimages where free fluid or tissue edema results in elevatedsignal intensity. T2W images obtained with a two-dimen-sional, single-shot fast spin-echo (ssT2) technique aremotion insensitive sequences that retain excellent in-plane

spatial resolution even in freely breathing patients.Acquisition times of approximately 1 slice per secondmaybe achieved by combining a single-shot technique withpartial Fourier transformation. In addition, imaging ofthe pelvis benefits from the addition of a high-resolution,three-dimensional T2-weighted turbo spin-echo sequencethat utilizes variable flip angle distribution. While thissequence is motion sensitive, it provides volumetric thin(~1 mm) sections that may subsequently be reformattedinto different planes, providing excellent anatomic depic-tion of the uterus, ovaries, and perineum.

Normal fat signal may obscure visibility of diseasedtissue, while fat-suppressed images allow distinction be-

Fig. 2. Cervicitis in a 23-year-old woman who presented withpelvic pain. Cervical discharge and cervical motion tendernesswere noted on exam; cervical swab for Chlamydia was positive.Axial T2W FS images at the level of the cervix (A) and uterinebody (B), and a T2W parasagittal image through the uterus

(C) show marked edema in the cervix (long arrows in A, B, C).Note the normal T2 signal intensity of the adjacent uterinemyometrium (short arrows in A, B, C). Axial T1W FS pre-(D) and post-contrast (E) images at the level of the cervix showcorresponding hyperenhancement (arrowheads in D, E).

F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review 939

tween intra-pelvic fat and inflammatory edema. Fatsuppression utilizing a spectral adiabatic inversion-re-covery (SPAIR) technique has been found to produceimproved suppression of lipid signal over conventionalinversion-recovery or spectral saturation techniques [21].This SPAIR technique allows the fat-suppressed T2Wimages to serve as a sensitive marker sequence for edemaand inflammatory changes. The detection of edema withfat-suppressed ssT2 sequences provides higher levels ofcontrast and therefore higher sensitivity for inflamma-

tory changes in the affected tissues and in the sur-rounding retroperitoneal and mesenteric fat.

MRI findings in acute PID

Cervicitis/endometritis

Cervicitis and endometritis represent the earliest stage ofinfection in PID. The normal endocervix and en-dometrium are T2 hyperintense relative to the underlyingjunctional zone and myometrium, which are markedly

Fig. 3. Salpingitis in a 20-year-old woman with lowerabdominal pain for 3 days. Cervical exam in the emer-gency department showed edema and adnexal tender-ness, vaginal swab for Gonorrhea was positive. Axial T2WTSE (A, B, C) and axial T2W FS (D) images through the

pelvis show a mildly dilated left fallopian tube (long arrows)and normal ovaries (arrowheads). Note the markedparametrial edema (D), and corresponding enhancement(short arrows) on axial T1W FS pre- (E) and post-contrast(F) images.

940 F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review

T2 hypointense, similar to normal smooth muscle atother anatomic sites. MRI has excellent sensitivity indemonstrating inflammation and edema on fat-sup-pressed (FS) T2-weighted (T2W) sequences, whichmanifests as increased T2 signal in the cervical anduterine myometrium (Figs. 1, 2). Inflammation may alsocause thickening of the normally T2 hyperintenseendometrial stripe. Gas in the endometrial cavity thatoccurs as a sequela of infection by gas-producingorganisms will present as small T1 and T2 hypointensefoci that demonstrate blooming artifact on in phase T1-weighted dual-echo sequences [22]. Thickening of theinflamed uterosacral ligaments is another finding ofcervicitis that is well seen with MRI. If contrast is used,hyperenhancement and vascular engorgement centeredat the cervix and the endometrium are typical findings(Figs. 1, 6) [23]. As in all forms of PID, small amounts ofperitoneal fluid may be present, often with some degreeof peritoneal enhancement (Fig. 6).

It should be noted that cervicitis is usually readilyapparent on speculum exam which may be suggested incases where the imaging abnormality is mild or non-specific (e.g., mild cervical edema and small freeintraperitoneal fluid). It is also important to rememberthat cervicitis is common in sexually active women and isoften idiopathic or caused by organisms not associatedwith PID (e.g., herpes simplex virus), and therefore,cervicitis alone does not necessarily indicate the presenceof PID unless other laboratory or clinical findings arepresent to support the diagnosis [24].

Salpingitis/pyosalpinx/oophoritis

Salpingitis manifests as wall thickening and enhancementof a nondilated or minimally dilated fallopian tube. Asnon-distended fallopian tubes are not usually visible onMRI, salpingitis may only appear as parametrialenhancement, pelvic edema, and thickening of the fascialplanes, and the findings may be difficult to distinguishfrom endometritis (Figs. 3, 4).

Pyosalpinx, hematosalpinx, and hydrosalpinx are allpresent with fluid-filled, distended fallopian tubes [25]. Inhydrosalpinx the tube is usually distended with simplefluid without wall thickening, hyperenhancement, oredema (Fig. 9). When pyosalpinx develops, the distendedtube may be thick walled and hyperenhancing, and isfilled with fluid of variable T1 and T2 signal intensitiesdepending on protein content (Fig. 5). Diffusion-weigh-ted images (DWI) are helpful for the diagnosis of infec-tion in the setting of dilated fallopian tubes, withpyosalpinx demonstrating abnormal, restricted diffusion(Fig. 10). In hematosalpinx, the distended tube is filledwith T1 hyperintense blood products of variable butusually low T2 signal, with no hyperenhancement oredema. Hydrosalpinx as an isolated finding is usuallyseen in chronic PID or endometriosis, rarely in acute

PID. Hematosalpinx as an isolated finding is unusual inPID and more likely indicates endometriosis [25].Oophoritis usually occurs in association with salpingitis,and manifests as enlargement, edema, and a polycysticappearance of the involved ovary with adjacent inflam-matory changes [16] (Fig. 6).

When an adnexal abnormality is identified on imagingin a reproductive age non-pregnant woman with abdom-inal pain, ovarian torsion must be considered in the dif-ferential diagnosis. While there is overlap of the imagingfindings of adnexal inflammation and ovarian torsion,these entities can usually be distinguished with confidenceon MRI. Ovarian torsion causes edema in the ovarianstroma similar to oophoritis, however, other MRI char-

Fig. 4. Salpingitis in a 33-year-old woman with known pelvicinflammatory disease previously treated for a tuboovarianabscess who presented with continued pelvic pain. Axial T2WFS (A) and T1W FS pre- (B) and post-contrast (C) axialimages show edema and an inflammatory mass (phlegmon;arrowheads in B and C) in the left adnexa. A mildly dilated leftfallopian tube (arrows in A and C) is partially visible.

F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review 941

acteristics of ovarian torsion including a twisted vascularpedicle, enlargement of the central stroma, and peripheraldisplacement of follicles are absent in oophoritis [26].

It is important to be mindful of ovarian vein throm-bosis when evaluating a woman with acute pelvic pain aspatients with thrombus in the ovarian vein may needanticoagulation to prevent pulmonary artery throm-boembolism [27, 28]. Similar to any other acute inflam-matory condition in the abdomen and pelvis, PIDpredisposes to venous thrombosis. The routine acquisi-tion of multiple phases in contrast-enhanced MRI allowsfor easy assessment of the pelvic vasculature (Fig. 7). Inpatients who cannot receive contrast, bright bloodimaging such as a high-resolution steady state-free pre-cession sequence can be used to assess vessel patency.

Tuboovarian abscess (TOA)

The primary objective of imaging patients with PID isdetecting complications that may require inpatient

admission and potentially invasive therapy. Patients withuncomplicated PID are managed as outpatients withantibiotics, while patients with complications such asTOA usually require inpatient admission and sometimespercutaneous drainage. While the incidence of TOA hasnot been extensively studied, a recent report examining73 women with acute PID found TOA in 44 patients,which corresponds to a TOA incidence of approximately60% among women acutely symptomatic of PID [29].

At MRI, TOA usually appears as a complex pelvicmass with a fluid component, surrounding edema,enhancing thick walls and septations (Figs. 7, 8).Hydrosalpinx, which will be subsequently discussed inmore detail, may appear similar to TOA; however,hydrosalpinx has an overall less complex appearancewith thinner walls and incomplete septa (Fig. 9) [25].

In some cases, TOA may be difficult to distinguishfrom ovarian malignancy based on imaging alone. InTOA, a fluid-filled tubular structure representing pyos-alpinx is often seen adjacent to the abscess. This is an

Fig. 5. Salpingitis in a 37-year-old woman with pelvic painand vaginal discharge. Axial T2W TSE image (A) of the pelvisshows a serpiginous fluid-filled structure in the right adnexa(long arrow in A), a typical appearance of a distended fal-

lopian tube. On the axial T2W FS image (B) edema is seenaround the tube (arrowhead in B). On the axial T1W FS pre-(C) and post-contrast (D) images, the tube has marked wallthickening and enhancement (arrow in D).

942 F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review

unusual finding in ovarian malignancy [30]. Sometimes,however, only clinical history will reliably distinguishTOA from an ovarian mass.

Peritonitis/Fitz-Hugh–Curtis

PID may cause an active perihepatitis, with edema andcapsular/subcapsular hyperemia, a complication termedFitz-Hugh–Curtis syndrome (FHC). FHC manifests onMRI as hepatic capsular and subcapsular enhancementon the parenchymal arterial phase post-contrast images(Fig. 11). In chronic FHC, subcapsular fibrosis mani-

festing as delayed portal venous phase contrastenhancement in the peripheral liver, localized perihepaticascites, and perihepatic fibrous adhesions may develop[31]. FHC may be suggested in a patient who presentwith upper abdominal pain, and has imaging evidence ofPID in the pelvis as well as hepatic pericapsular or sub-capsular edema and enhancement.

While the therapy for FHC is usually the same asPID, it is important to suggest FHC in patients who meetthe clinical and imaging criteria to avoid further unnec-essary workup and treatment for other presumed eti-ologies of upper abdominal pain. In limited cases of

Fig. 6. Cervicitis and oophoritis in a 23-year-old womanwith pelvic pain. Adnexal tenderness was noted on pelvicexam. Cervical swab for Chlamydia done in the emergencyroom was positive. Axial T2W TSE image of the pelvisA shows edema in the right ovary (long arrow in A). Notethe normal left ovary (arrowhead in A). There is a smallamount of simple-appearing free fluid in the pelvis, and

smooth peritoneal enhancement in the pelvis on the T1WFS post-contrast image (short arrow in B). Axial T2W FSimage of the pelvis at the level of the cervix C shows cer-vical enlargement and edema (double arrows in C), axialT1W FS post-contrast image at the same level D showsmarked contrast enhancement of the cervix (double arrowsin D).

F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review 943

intractable upper abdominal pain from chronic FHC,laparoscopic lysis of perihepatic adhesions has beenshown to offer symptomatic relief [32].

The detection of FHC requires scanning the entireabdomen and pelvis, while most other complications ofPID will be detected on imaging of the pelvis only. Whenprescribing the scan range in a patient being evaluatedfor PID, the examination should be tailored to answer

the specific clinical question on a case-by-case basis. Inpatients whose symptoms are limited to the pelvis, cov-erage of the pelvis only should be sufficient as the clini-cian is usually interested in whether a TOA is present. Inpatients who have generalized abdominal pain, an ab-domen–pelvis study should be performed to evaluate forperitonitis, fluid collections outside of the pelvis, andetiologies of abdominal pain not related to PID.

Fig. 7. Salpingitis, oophoritis, and ovarian abscess compli-cated by ovarian vein thrombosis in a 30-year-old woman whopresented with fever, nausea, and shortness of breath. AxialT2W FS image of the pelvis A shows an edematous right ovary(double arrows in A) and an intra-ovarian fluid collection whichon the T1W FS post-contrast imageB shows rim enhancement

(long arrow in A and B) consistent with oophoritis and intrao-varian abscess. A para-sagittal T2W TSE image through theright adnexa C shows a dilated and thick-walled right fallopiantube (arrowheads in C) in keeping with salpingitis. Axial T1WFS post-contrast image through the pelvis D shows a thrombusin the right ovarian vein (short arrow in D).

944 F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review

MRI findings in subclinical PID

Hydrosalpinx

Hydrosalpinx develops after the acute inflammation inPID has resolved, and is due to scarring of the fallopiantubes or to the formation of peritoneal bands that resultin fallopian tube obstruction. The obstructed and unin-flamed tubes over time fill with simple fluid. Even amongwomen with known subclinical PID or resolved PID, the

presence of hydrosalpinx has important implications:among women with tubal infertility, those with hydros-alpinx have a lower rate of success with in vitro fertil-ization and higher rates of early pregnancy loss [33]. Thetreatment of isolated hydrosalpinx depends on the clin-ical scenario [34]. In some cases, no treatment may benecessary. Elective surgery is sometimes offered ashydrosalpinx may cause adnexal torsion [35]. Patientswith hydrosalpinx who are unable to conceive or have

Fig. 8. Tubo-ovarian abscess in a 22-year-old woman withback pain and abdominal pain. A vaginal swab for gonorrheaperformed in the emergency department was positive. T2WTSE image through the pelvis A shows a complex cystic fluidcollection in the pelvis (long arrows in A) with rim enhance-ment on the T1W FS post-contrast image at the same level

(B, arrowhead) and surrounding pelvic and retroperitonealedema best seen on the T2W FS image (C, short arrow). Thecollection exerts mass effect on the pelvic organs. Aparasagittal T2W TSE image (D) through the left adnexashows that the left ovary is contained within the collection(double arrows in D).

F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review 945

had pregnancy loss may require the use of assistedreproductive techniques. In this context, salpingectomy,tubal occlusion, or tubal aspiration have been shown toincrease the likelihood of a successful pregnancy [36].

MRI can effectively characterize hydrosalpinx and inmost cases reliably distinguish it from other cysticstructures in the adnexa [37]. Normal caliber fallopian

tubes are not seen on MRI unless they are outlined byfluid. Hydrosalpinx appears as a thin-walled fluid-filledcystic mass closely related to but separate from theipsilateral ovary with a serpentine, usually C- orS-shaped configuration containing incomplete longitu-dinal folds (Fig. 9) [25]. The tube contains fluid of vari-able T1 intensity: highly proteinaceous fluid may be T1hyperintense, and simple fluid is T1 hypointense. In casesof hydrosalpinx with no active pelvic inflammation, thetube wall is thin and smooth with no edema and minimalcontrast enhancement.

PID is the most common cause of hydrosalpinx.Other possible etiologies are endometriosis, fallopiantube malignancy, and pelvic adhesions from other causesof inflammation such as inflammatory bowel disease orsurgery. These can be distinguished from PID-relatedhydrosalpinx based on the absence of other imagingfeatures of endometriosis or malignancy and also basedon clinical history.

Peritoneal inclusion cyst

On MRI inclusion cysts appear as thin-walled cysticstructures ranging in size from several millimeters to15–20 cm or larger. Cyst contents are most often simpleserous fluid producing low T1 and high T2 signal, al-though in some cases, more complex fluid may havemildly increased T1 signal. Cysts walls are thin with noenhancement or mild uniform enhancement (Fig. 12). Ifadhesions form along the surface of the ovary or near thefallopian tubes, peritoneal inclusion cysts may mimichydrosalpinx, may appear to engulf the ovary, or maymimic a cystic ovarian mass [38].

Other than PID, inclusion cysts can be sequela ofprior pelvic inflammation from any cause includinginfection, trauma, surgery, or endometriosis. Pelvicinclusion cysts are often symptomatic usually with pelvicpain, and when symptoms are pronounced, they mayrequire treatment. Conservative therapy with oral con-traceptives is favored as surgical treatment has a high

cFig. 10. Pyosalpinx in a 28-year-old woman with abdominalpain. Axial (A) and parasagittal (B) T2W TSE images throughthe pelvis show a markedly dilated fallopian tube (double ar-rows in A and B) posterior to the left ovary. Edema sur-rounding the fallopian tube is best seen on the axial T2W FSimage (C, long arrows). The fallopian tube contains fluid thatis slightly higher in T1 intensity (D, short arrow) but signifi-cantly lower in T2 intensity (double arrow in A, B) comparedto urine in the bladder (asterisk in B, D) in keeping with thecomplex purulent tube contents of pyosalpinx. On the T1WFS post-gadolinium image (E), the tube wall is thickened andenhancing in keeping with active inflammation (arrowhead inE). Diffusion-weighed image (F, B = 500) shows restricteddiffusion within the inflamed left fallopian tube (doublearrowhead in F) characteristic of pyosalpinx.

Fig. 9. Hydrosalpinx in a 38-year-old woman who presentedwith abdominal pain after cholecystectomy. Axial T2W TSEimage through the mid-pelvis A shows that the fallopian tubes(long arrows in A) are distended with simple fluid, similar in T2signal intensity to free intraperitoneal fluid in the pelvis (ar-rowhead in A). Axial T1W FS post-gadolinium image B ob-tained at the same level shows that the fallopian tube wall isuniform and thin with minimal enhancement (double arrows inB). There is a small amount of intraperitoneal fluid in thepelvis due to the recent cholecystectomy but no soft-tissueedema around the tubes or the adnexa.

946 F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review

F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review 947

948 F. Czeyda-Pommersheim et al.: MRI in pelvic inflammatory disease: a pictorial review

rate of cyst recurrence. Other treatment options includepercutaneous cyst aspiration and sclerotherapy [12].

Bowel/ureteral obstruction

Peritoneal or pelvic inflammation from PID may affectadjacent abdominal and pelvic organs both in the acuteand subclinical phases. Active inflammation can result insmall bowel ileus usually affecting pelvic bowel loops.When the acute phase subsides, post-inflammatoryperitoneal adhesions can result in small- or large-bowelobstruction [16]. If the inflammation extends into theretroperitoneum or the pelvis, it may result to ureteralstrictures. These complications are easily detected withMRI.

bFig. 11. FHC ina 37-year-old woman who presented with fever,chills, and abdominal pain after placement of an IUD. Axial T2WFS (A) and T1W FS post-contrast (B) images of the pelvis showmarked right adnexal edema (long arrow in A) and a complex,enhancing adnexal structure (double arrows in B) consistent witha right tubo-ovarian abscess. On the coronal T2W TSE (C) image,a small amount of perihepatic fluid (short arrow in C) is seensupporting the presence of peritoneal inflammation. Venousphase axial (D) and coronal (E) T1W FS post-contrast imageshows perihepatic/subcapsular enhancement (arrowheads in D,E). A venous phase coronal T1W FS post-contrast image of anormal liver (F) is shown for comparison from a different patientwith no subcapsular enhancement.

Fig. 12. Peritoneal inclusion cyst in a 38-year-old womanwith prior PID. Axial (A) and sagittal (B) T2W TSE and axialT1W FS post-contrast (C) images of the pelvis shows asimple cystic structure in the left adnexa (long arrow in

A) containing simple fluid similar in T2 signal intensity to urinein the bladder (double arrows in B). The cyst has a thin wallwith minimal to no enhancement (short arrow in C) and noassociated soft-tissue mass or mural nodularity.

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Conclusion

MRI is optimally suited for the evaluation of PID due toits high soft-tissue contrast and high sensitivity to detecteven subtle acute inflammation. PID is a common causeboth of acute and chronic abdominal pain and as such isseen with increasing frequency on MRI examinationsordered to evaluate women presenting with acute orchronic abdominal pain. Radiologists should rememberthis entity in the differential diagnosis in appropriatepatient populations and to be familiar with its manifes-tations on MRI. Imaging findings of uncomplicated PIDinclude pelvic fascial thickening, ovarian, cervical oruterine inflammation, and peritoneal enhancement.Potential complications are pyosalpinx or hydrosalpinx,diffuse abdominal peritonitis, perihepatitis, andtuboovarian abscess which may require hospitalizationand surgical or percutaneous treatment.

Compliance with ethical standards

Funding No funding was received for this study.

Conflict of interest The authors declare that they have no conflict ofinterest.

Ethical approval This study does not contain any studies with animalsperformed by any of the authors. All procedures performed in studiesinvolving human participants were in accordance with the ethicalstandards of the institutional and/or national research committee andwith the 1964 Helsinki declaration and its later amendments or com-parable ethical standards.

Informed consent Informed consent was obtained from all individualparticipants included in the study.

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