Diagnosing Acute Pelvic Pain: Appropriateness Criteria (ACR)

Premenopausal women with acute pelvic pain often pose a diagnostic dilemma. They often exhibit nonspecific signs and symptoms, the most common being nausea, vomiting, and leukocytosis. The differential considerations encompass gynecologic and obstetrical causes (e.g., hemorrhagic ovarian cysts, pelvic inflammatory disease, ovarian torsion, ectopic pregnancy, spontaneous abortion, or labor and placental abruption), as well as nongynecologic etiologies (e.g., appendicitis, inflammatory bowel disease, infectious enteritis, diverticulitis, urinary tract calculi, pyelonephritis, and pelvic thrombophlebitis). The choice of imaging modality is determined by the most likely clinically suspected differential diagnosis.

American College of Radiology in 2015 issued the ACR Appropriateness Criteria for acute pelvic pain in the reproductive age group. The major recommendations of the guidelines are as follows:-

• Acute pelvic pain in the reproductive age group presents a diagnostic challenge. US, CT, and MRI often playing an integral role in arriving at the correct diagnosis. The choice of the correct imaging test depends on the results of a careful clinical evaluation in order to narrow the differential diagnosis. Measuring the serum β-hCG level is the first step. TVS is the imaging procedure of choice to locate a pregnancy (assess the possibility of an ectopic versus intrauterine pregnancy) and the status of the fetus. TVS can sometimes distinguish malignant from benign ovarian masses and has a specificity of 98.7% in diagnosing a hemorrhagic cyst. TVS is the modality of choice in suspected pain from gynecologic origin. TVS with Doppler is useful in the diagnosis of ovarian torsion. CT performs well in the diagnosis of nongynecologic etiologies of acute pelvic pain. CT has a high sensitivity and specificity in the diagnosis of obstructive uropathy and appendicitis. CT is the preferred modality to assess diverticulitis, enteritis, and colitis. MRI can be used as a problem-solving tool in pregnant patients, and it has a high sensitivity and specificity in diagnosing appendicitis in this cohort.


• In a pregnant patient without acute signs of infection (please refer to ACR practice guidelines in pregnant patients) and with a suspected gynecologic etiology for pain, a pelvic US with adnexal Doppler would be the initial modality to assess the etiology. If the US is inconclusive, then MRI without contrast can be done for further evaluation. In a pregnant patient with suspected nongynecologic etiology for pain, US may be helpful but potentially challenging, particularly in the latter half of pregnancy. MRI is the most sensitive modality if appendicitis is suspected. The best modality to assess for renal calculi is a low-dose noncontrast CT. The addition of oral contrast to CT may help in diagnosing appendicitis, enteritis, colitis, or diverticulitis.


• In a nonpregnant patient presenting with abdominal pain and a suspected gynecologic etiology with no clinical signs of infection, US is the best initial modality. If inconclusive, the next best modality is contrast-enhanced MRI, followed by contrast-enhanced CT. If an infectious etiology is suspected, the best modality in a female of childbearing age is contrast-enhanced MRI.


• In a nonpregnant patient with pain suspected from a nongynecologic origin, a contrast-enhanced CT is the imaging modality of choice. In certain situations, dual-energy CT can be used and virtually unenhanced CT images reconstructed to assess for renal calculi. To avoid radiation exposure in a patient of childbearing age, MRI can be considered but is less sensitive for identification of small calculi with mild or early ureteral obstruction.


• The suspected etiology of the acute pelvic pain, whether it is obstetrical, gynecological, gastrointestinal, or urinary, will determine which pelvic imaging modality is the most appropriate for accurate and expeditious diagnosis and triage.

The authority has also issued the rating preferences of various diagnostic modalities based on the different clinical conditions. These can be summarised as follows:-

Clinical Condition: Acute Pelvic Pain in the Reproductive Age Group

Variant 1: Gynecological etiology suspected, serum β-hCG positive.

Radiologic Procedure	Rating	Comments	RRL*
US pelvis transvaginal	9	Both transvaginal and transabdominal US should be performed if possible.	O
US pelvis transabdominal	9	Both transvaginal and transabdominal US should be performed if possible.	O
US duplex Doppler adnexa	8		O
MRI pelvis without contrast	6	This procedure can be performed if US is inconclusive or nondiagnostic. See the Summary of Literature Review below and ACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for use of contrast media.	O
MRI abdomen and pelvis without contrast	6	This procedure can be performed if US is inconclusive or nondiagnostic. See the Summary of Literature Review below and ACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for use of contrast media.	O
MRI pelvis without and with contrast	1		O
MRI abdomen and pelvis without and with contrast	1		O
CT pelvis without contrast	1
CT pelvis with contrast	1
CT pelvis without and with contrast	1
CT abdomen and pelvis without contrast	1
CT abdomen and pelvis with contrast	1
CT abdomen and pelvis without and with contrast	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Variant 2: Gynecological etiology suspected, serum β-hCG negative.

Radiologic Procedure	Rating	Comments	RRL*
US pelvis transvaginal	9	Both transvaginal and transabdominal US should be performed if possible.	O
US pelvis transabdominal	9	Both transvaginal and transabdominal US should be performed if possible.	O
US duplex Doppler pelvis	9		O
MRI pelvis without and with contrast	6	This procedure can be performed if US is inconclusive or nondiagnostic. See the Summary of Literature Review below and ACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for the use of contrast media.	O
MRI abdomen and pelvis without and with contrast	6	This procedure can be performed if US is inconclusive or nondiagnostic. See the Summary of Literature Review below and ACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for the use of contrast media.	O
MRI pelvis without contrast	4	This procedure can be performed if US is inconclusive or nondiagnostic. See the Summary of Literature Review below and ACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for the use of contrast media.	O
MRI abdomen and pelvis without contrast	4	This procedure can be performed if US is inconclusive or nondiagnostic. See the Summary of Literature Review below and ACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for the use of contrast media.	O
CT abdomen and pelvis with contrast	4	This procedure can be performed if US is inconclusive or nondiagnostic and MRI is not available. See the Summary of Literature Review below for the use of contrast media.
CT pelvis with contrast	4	This procedure can be performed if US is inconclusive or nondiagnostic and MRI is not available. In young women undergoing repeat imaging, the cumulative radiation dose should be considered. See the Summary of Literature Review below for the use of contrast media.
CT pelvis without contrast	2	This procedure can be performed if US is inconclusive or nondiagnostic and MRI is not available. In young women undergoing repeat imaging, cumulative radiation dose should be considered.
CT pelvis without and with contrast	2
CT abdomen and pelvis without contrast	2
CT abdomen and pelvis without and with contrast	2
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Variant 3: Nongynecological etiology suspected, serum β-hCG positive.

Radiologic Procedure	Rating	Comments	RRL*
US pelvis transvaginal	9	This procedure is usually performed in conjunction with transabdominal US.	O
US abdomen and pelvis transabdominal	9	Add transvaginal US as indicated.	O
US duplex Doppler adnexa	8		O
MRI abdomen and pelvis without contrast	8	See the Summary of Literature Review below andACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for use of contrast media.	O
CT abdomen and pelvis with contrast	4	This procedure can be performed if US is nondiagnostic and MRI is unavailable or equivocal or for prompt diagnosis of a potentially life-threatening condition. See the Summary of Literature Review below for the use of contrast media.
CT abdomen and pelvis without contrast	3	Literature suggests that noncontrast low-dose CT is better than US for diagnosing appendicitis, diverticulitis, enteritis, and renal calculi.
MRI abdomen and pelvis without and with contrast	2	See the Summary of Literature Review below andACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for the use of contrast media.	O
CT abdomen and pelvis without and with contrast	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Variant 4: Nongynecological etiology suspected, serum β-hCG negative.

Radiologic Procedure	Rating	Comments	RRL*
CT abdomen and pelvis with contrast	9
US abdomen and pelvis transabdominal	7	This procedure can be appropriate for suspected appendicitis and urinary tract pathology and to minimize radiation exposure.	O
US duplex Doppler pelvis	7	Doppler can be used as an adjunct to assess for appendicitis or to evaluate ureteral jets for obstructive versus nonobstructive pathology.	O
CT abdomen and pelvis without contrast	6
MRI abdomen and pelvis without and with contrast	6	This procedure can be used to avoid the radiation exposure of CT in a young patient or if US is inconclusive or nondiagnostic. See the Summary of Literature Review below and ACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for the use of contrast media.	O
MRI abdomen and pelvis without contrast	4	This procedure can be used to avoid the radiation exposure of CT in a young patient or if US is inconclusive or nondiagnostic. See the Summary of Literature Review below and ACR Manual on Contrast Media (see the "Availability of Companion Documents" field) for the use of contrast media.	O
US pelvis transvaginal	4		O
CT abdomen and pelvis without and with contrast	2
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*RelativeRadiation Level

You can read the full guidelines by clicking on the following link:-

https://acsearch.acr.org/docs/69503/Narrative