Acute abdominal and pelvic pain in pregnancy: MR imaging as a valuable adjunct to ultrasound?

2024 Clinical Practice Guideline Update by the Infectious Diseases Society of America on Complicated Intra-abdominal Infections: Diagnostic Imaging of Suspected Acute Appendicitis in Adults, Children, and Pregnant People

This paper is part of a clinical practice guideline update on the risk assessment, diagnostic imaging, and microbiological evaluation of complicated intra-abdominal infections in adults, children, and pregnant people, developed by the Infectious Diseases Society of America (IDSA). In this paper, the panel provides recommendations for diagnostic imaging of suspected acute appendicitis. The panel's recommendations are based on evidence derived from systematic literature reviews and adhere to a standardized methodology for rating the certainty of evidence and strength of recommendation according to the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach.

Using MRI appendicitis scale and DWI for the diagnosis of acute appendicitis in pregnant women

OBJECTIVES

To assess the performance of MRI scale for the diagnosis of acute appendicitis in pregnant women and to determine the added diagnostic value of diffusion-weighted imaging (DWI).

METHODS

From January 2018 to December 2020, 80 patients were included. All MRI were performed with a 1.5-Tesla scanner with anterior array body coil. This analysis included (1) T2-weighted imaging (T2WI), (2) fat-saturated T2WI, and (3) DWI. Two radiologists blinded to the diagnosis recorded their assessment of four findings: appendiceal diameter, appendiceal wall thickness, luminal mucus, and periappendiceal inflammation. The MRI scale of acute appendicitis which ranged from 0 to 4 was determined from these factors. An additional one point was added to the MRI appendicitis scale in those patients with evidence of appendiceal restricted diffusion on DWI. The diagnostic values and predictive factors were computed.

RESULTS

Multivariate analysis demonstrated that the calculated MRI appendicitis scale was a significant independent predictor of acute appendicitis with a sensitivity of 96.6%, specificity of 90.2%, and PPV of 84.8%. The odds ratio of appendicitis is increased by 22.3 times for every increase in one point on the MRI appendicitis scale. Therefore, the addition of one point for restricted diffusion in the appendix on DWI imaging can add substantial value, both positive and negative predictive value, towards making an accurate diagnosis of acute appendicitis.

CONCLUSIONS

MRI appendicitis scale is an objective and significant independent predictive factor for acute appendicitis in pregnant women. Incorporation of diffusion weighted imaging to MRI can improve diagnosis of acute appendicitis.

CLINICAL RELEVANCE STATEMENT

MRI appendicitis scale is an objective and significant independent predictor of acute appendicitis in pregnant women. Incorporation of DWI/ADC map to MRI examinations can improve diagnosis of acute appendicitis in pregnant women.

KEY POINTS

• MRI appendicitis scale is an objective and significant independent predictive factor for acute appendicitis in pregnant women. • The odds ratio of appendicitis can be increased by 22.3 times for every increase of one unit in MRI scale. • Incorporation of diffusion-weighted imaging to MRI examinations can add value to the scale (4.2 ± 0.7 vs. 0.7 ± 1.1; p < 0.001) among pregnant women with appendicitis versus pregnant women without appendicitis.

Imaging of Acute Abdominopelvic Pain in Pregnancy and Puerperium-Part II: Non-Obstetric Complications

Emergency imaging in pregnancy and puerperium poses unique challenges both for clinicians and radiologists, requiring timely and accurate diagnosis. Delay in treatment may result in poor outcomes for both the patient and the foetus. Pregnant and puerperal patients may present in the emergency setting with acute abdominopelvic pain for various complications that can be broadly classified into obstetric and non-obstetric related diseases. Ultrasonography (US) is the primary diagnostic imaging test; however, it may be limited due to the patient's body habitus and the overlapping of bowel loops. Computed tomography (CT) carries exposure to ionising radiation to the foetus, but may be necessary in selected cases. Magnetic resonance imaging (MRI) is a valuable complement to US in the determination of the etiology of acute abdominal pain and can be used in most settings, allowing for the identification of a broad spectrum of pathologies with a limited protocol of sequences. In this second section, we review the common non-obstetric causes for acute abdominopelvic pain in pregnancy and post partum, offering a practical approach for diagnosis and pointing out the role of imaging methods (US, MRI, CT) with the respective imaging findings.

Imaging of Acute Abdominopelvic Pain in Pregnancy and Puerperium-Part I: Obstetric (Non-Fetal) Complications

Acute abdominopelvic pain in pregnant and postpartum patients presents clinical and therapeutic challenges, often requiring quick and accurate imaging diagnosis. Ultrasound remains the primary imaging investigation. Magnetic resonance imaging (MRI) has been shown to be a powerful diagnostic tool in the setting of acute abdominal pain during pregnancy and puerperium. MRI overcomes some drawbacks of US, avoiding the ionizing radiation exposure of a computed tomography (CT) scan. Although CT is not usually appropriate in pregnant patients, it is crucial in the emergency evaluation of postpartum complications. The aim of this article is to provide radiologists with a thorough familiarity with the common and uncommon pregnancy and puerperium abdominal emergencies by illustrating their imaging appearances. The present first section will review and discuss the imaging findings for acute abdominopelvic pain of obstetric (non-fetal) etiology.

Acute Abdomen in Pregnancy: A Comprehensive Review of Diagnosis and Management

An unusual diagnostic and treatment challenge is presented by an acute abdomen during pregnancy. Obstetric factors and other causes unrelated to pregnancy also contribute to acute abdominal discomfort in pregnancy. Due to the changing clinical presentations brought on by the anatomical and physiological changes of pregnancy as well as the hesitation to utilize certain radiological studies out of concern about damaging the fetus, the diagnosis of the acute abdomen during pregnancy can be challenging. Delays in identification and treatment may have negative effects on the mother as well as the fetus. This review sheds light on the importance of anatomical and physiological considerations, early diagnoses, and understanding the various modalities and etiologies of acute abdomen in pregnancy (AAP). We then move on to discuss the various diagnostic techniques that can help the physician determine the causes and plan well-informed treatment. We examine and contrast different radiographic tests, including X-rays, computed tomography, magnetic resonance imaging, and ultrasound. We also talk about the various roles that these investigational methods can play in the evaluation and treatment throughout the duration of the pregnancy. The paper additionally addresses how to handle patients who appear with AAP and the different techniques used to treat them, including pre-operative laparoscopy. Before going over some more broad points that might be useful, we eventually dive into some of the more intriguing etiologies relating to AAP, such as isolated tubal torsion and neoplastic complications.

MRI remains highly accurate in the diagnosis of appendicitis in pregnancy when read by radiologists of mixed specialty training and experience

PURPOSE

To audit the accuracy of magnetic resonance imaging (MRI) abdominal studies performed in the diagnosis of appendicitis in pregnant patients when read by radiologists of mixed experience.

METHODS

MRI reports from 45 pregnant women presenting to our emergency department for the investigation of appendicitis between 2009 and 2020 were retrospectively reviewed. Where available, these reports were correlated with surgical and pathology reports as well as follow-up clinical information. Following a review of literature, accuracy targets were set. Statistical analyses including sensitivity, specificity, positive, and negative predictive values were calculated.

RESULTS

A total of 18 radiology consultants read 45 MRI abdominal studies in the assessment of appendicitis during pregnancy with 62% (n = 28) of these read by specialist radiologists and the remainder by general radiologists. This yielded an accuracy in diagnosis of 99.8%, sensitivity of 80% (95% CI: 49-94.3%), and specificity of 100% (95% CI: 90-100%). The calculated negative predictive value was 94.6% (95% CI: 82.3-98.5%), and positive predictive value was 100% (95% CI: 90-100%). The appendix was not identified in 19 patients (42%). A statistically significant relationship between the presence of right iliac fossa stranding of the fat OR free fluid was associated with appendicitis (p = 0.01). Alternate diagnoses were identified in 8% (n = 4) of cases.

CONCLUSION

MRI is a highly accurate imaging modality for the assessment of appendicitis in pregnancy. Even with variable reader MRI experience, MRI demonstrates an accuracy of 99.8% and a positive predictive value for acute appendicitis of 100%. Double reading and the possible inclusion of DWI may help further improve accuracy and minimise false-negative rates.

Pancreatitis in Pregnancy-Comprehensive Review

Acute and chronic pancreatitis, until recently observed incidentally in pregnancy, has occurred much more frequently in the last 2-3 decades. Particularly severe complications for the mother and fetus may be a consequence of acute pancreatitis. Therefore, it is important to know more about the diagnostic and therapeutic possibilities of pancreatic diseases in the course of pregnancy. Epidemiology, causes, clinical characteristics, differential diagnosis, and complex management are presented in this review. Particular emphasis is on the prevention of acute pancreatitis (AP) through the proper diagnosis and treatment of cholelithiasis and hypertriglyceridemia, both before and during pregnancy. The most up-to-date reports and management strategies are presented. This publication contributes to a wide group of scientists and practitioners better understanding the discussed issues, and indicates the directions of research for the future.

Assessment of postpartum haemorrhage for placenta accreta: Is measurement of myometrium thickness and dark intraplacental bands using MRI helpful?

Background

This study aimed to investigate the predictive values of magnetic resonance imaging (MRI) myometrial thickness grading and dark intraplacental band (DIB) volumetry for blood loss in patients with placenta accreta spectrum (PAS).

Methods

Images and clinical data were acquired from patients who underwent placenta MRI examinations and were diagnosed with PAS from March 2015 to January 2021. Two radiologists jointly diagnosed, processed, and analysed the MR images of each patient. The analysis included MRI-based determination of placental attachment, as well as myometrial thickness grading and DIB volumetry. The patients included in the study were divided into three groups according to the estimated blood loss volume: in the general blood loss (GBL) group, the estimated blood loss volume was < 1000 ml; in the massive blood loss (MBL) group, the estimated blood loss volume was ≥ 1000 ml and < 2000 ml; and in the extremely massive blood loss (ex-MBL) group, the estimated blood loss volume was ≥ 2000 ml. The categorical, normally distributed, and non-normally distributed data were respectively analysed by the Chi-square, single-factor analysis of variance, and Kruskal–Wallis tests, respectively. The verification of correlation was completed by Spearman correlation analysis. The evaluation capabilities of indicators were assessed using receiver operating characteristic curves.

Results

Among 75 patients, 25 were included in the GBL group, 26 in the MBL group, and 24 in the ex-MBL group. A significant negative correlation was observed between the grade of myometrial thickness and the estimated blood loss (P < 0.001, ρ = − 0.604). There was a significant positive correlation between the volume of the DIB and the estimated blood loss (P < 0.001, ρ = 0.653). The areas under the receiver operating characteristic curve of the two MRI features for predicting blood loss ≥ 2000 ml were 0.776 and 0.897, respectively.

Conclusions

The grading and volumetric MRI features, myometrial thickness, and volume of DIB, can be used as good prediction indicators of the risk of postpartum haemorrhage in patients with PAS.

MRI as First Line Imaging for Suspected Acute Appendicitis during Pregnancy: Diagnostic Accuracy and level of Inter-Radiologist Agreement

OBJECTIVE

Evaluation of acute appendicitis (AA) in pregnancy is supported with diagnostic imaging. Typically, ultrasound (US) is performed first, and then often followed by magnetic resonance imaging (MRI) due to continued diagnostic uncertainty. The purpose of our study was to evaluate the sensitivity, specificity, and accuracy of US as compared to MRI and to evaluate the inter-radiologist agreement amongst body Radiologists with varying levels of expertise.

MATERIALS AND METHODS

We performed a retrospective study of 364 consecutive pregnant patients with clinical suspicion of AA at a single center over a 6-year period. Sensitivity, Specificity, accuracy, positive and negative predictive values were calculated for US and MRI. Inter Radiologist agreement was determined using Cohen's Kappa analysis between original interpreting Radiologist and retrospective review by expert Radiologist.

RESULTS

Thirty-one of 364 patients (8.5%) underwent appendectomy based on preoperative diagnosis, with confirmation of acute appendicitis (AA) by pathology in 19. US was able to visualize the appendix in only 6 (1.65%), 5 of whom had appendicitis. 141 patients underwent MRI, and correctly diagnosed appendicitis in 9. No patient with a negative MRI diagnosis had AA. The sensitivity, and negative predictive value for diagnosing AA with MRI was 100%. The MRI inter-reader agreement for appendix visualization and overall accuracy were 87.9 and 98% with Cohen Kappa of 0.7 and 0.56 respectively.

CONCLUSIONS

Our data suggests that MRI should be considered the first line imaging modality in pregnant patients suspected of having AA. Body Radiologists with varied levels of experience in MRI readouts had substantial agreement.

Diagnostic dilemma between angular and interstitial ectopic pregnancy: 3D ultrasound features

Angular pregnancy is a rare entity which is commonly confused with interstitial or cornual pregnancies. A lack of consensus about the specific ultrasound features of these 3 entities leads to inappropriate interchange between them among the literature. An angular pregnancy should be considered as a potentially viable intra-uterine eccentric pregnancy as it might be carried to term and result in a live-born baby whereas interstitial or cornual pregnancies should be considered as ectopic pregnancies which should be interrupted. We report here two cases of women at 8 weeks of pregnancy with an angular pregnancy diagnosed by vaginal 2D and 3D ultrasound and discuss about specific ultrasound features and alternative imaging modalities to distinguish it from interstitial and cornual pregnancies.

Magnetic resonance imaging (MRI) for diagnosis of acute appendicitis

BACKGROUND

Appendicitis remains a difficult disease to diagnose, and imaging adjuncts are commonly employed. Magnetic resonance imaging (MRI) is an imaging test that can be used to diagnose appendicitis. It is not commonly regarded as a first-line imaging test for appendicitis, but the reported diagnostic accuracy in some studies is equivalent to computed tomography (CT) scans. As it does not expose patients to radiation, it is an attractive imaging modality, particularly in women and children.

OBJECTIVES

The primary objective was to determine the diagnostic accuracy of MRI for detecting appendicitis in all patients. Secondary objectives: To investigate the accuracy of MRI in subgroups of pregnant women, children, and adults. To investigate the potential influence of MRI scanning variables such as sequences, slice thickness, or field of view.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase until February 2021. We searched the references of included studies and other systematic reviews to identify further studies. We did not exclude studies that were unpublished, published in another language, or retrospective.

SELECTION CRITERIA

We included studies that compared the outcome of an MRI scan for suspected appendicitis with a reference standard of histology, intraoperative findings, or clinical follow-up. Three study team members independently filtered search results for eligible studies.

DATA COLLECTION AND ANALYSIS

We independently extracted study data and assessed study quality using the Quality Assessment of Studies of Diagnostic Accuracy - Revised (QUADAS-2) tool. We used the bivariate model to calculate pooled estimates of sensitivity and specificity.

MAIN RESULTS

We identified 58 studies with sufficient data for meta-analysis including a total of 7462 participants (1980 with and 5482 without acute appendicitis). Estimates of sensitivity ranged from 0.18 to 1.0; estimates of specificity ranged from 0.4 to 1.0. Summary sensitivity was 0.95 (95% confidence interval (CI) 0.94 to 0.97); summary specificity was 0.96 (95% CI 0.95 to 0.97). Sensitivity and specificity remained high on subgroup analysis for pregnant women (sensitivity 0.96 (95% CI 0.88 to 0.99); specificity 0.97 (95% CI 0.95 to 0.98); 21 studies, 2282 women); children (sensitivity 0.96 (95% CI 0.95 to 0.97); specificity 0.96 (95% CI 0.92 to 0.98); 17 studies, 2794 children); and adults (sensitivity 0.96 (95% CI 0.93 to 0.97); specificity 0.93 (95% CI 0.80 to 0.98); 9 studies, 1088 participants), as well as different scanning techniques. In a hypothetical cohort of 1000 patients, there would be 12 false-positive results and 30 false-negative results. Methodological quality of the included studies was poor, and the risk of bias was high or unclear in 53% to 83% of the QUADAS-2 domains.

AUTHORS' CONCLUSIONS

MRI appears to be highly accurate in confirming and excluding acute appendicitis in adults, children, and pregnant women regardless of protocol. The methodological quality of the included studies was generally low due to incomplete and low standards of follow-up, so summary estimates of sensitivity and specificity may be biased. We could not assess the impact and direction of potential bias given the very low number of high-quality studies. Studies comparing MRI protocols were few, and although we found no influence of MRI protocol variables on the summary estimates of accuracy, our results do not rule out that some MRI protocols are more accurate than others.

The diagnostic accuracy of ultrasound in the diagnosis of acute appendicitis in pregnancy

Objective: Clinically suspected appendicitis is the most common nonobstetric surgical problem encountered in pregnancy. The diagnosis of appendicitis is hampered by equivocal symptoms during pregnancy. Ultrasonography (US) remains, as a rule, the imaging test of choice for the diagnosis of clinically suspected appendicitis during pregnancy and other imaging tools such as computed tomography (CT) or magnetic resonance imaging (MRI) are usually avoided. We evaluated the accuracy of US in the diagnosis of appendicitis during pregnancy.Methods: The clinical and sonographic findings of all pregnant women (n = 90), who underwent appendectomy between January 2005 and December 2017 at our institution, were retrospectively reviewed, analyzed, and compared to the clinical and sonographic findings similarly obtained for a control group of nonpregnant women matched for age and date of surgery (±6 months). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of ultrasonic findings were calculated and compared between groups as well as within the three pregnancy trimesters.Results: The mean age of the patients was 31.3 ± 0.4. Right lower quadrant pain was present in almost all patients (99%). The sole imaging modality used in our study cohort was US. Among nonpregnant controls, CT scan was primarily used on more occasions (53.3%) compared to US (45.6%). Nonpregnant women underwent significantly more laparoscopies compared to pregnant women (83.3 versus 45.6%, p < .001). The rate of negative appendectomy was higher in pregnant women (31.1 versus 10%, p = .002). Among pregnant women operated there was a higher rate of inconclusive or negative imaging (43.3 versus 11.1%, p < .001). The rate of perforated appendix at surgery was similar in both groups (6.7 and 4.4%, respectively, p = .75).Conclusions: Ultrasonography (US) is of mediocre accuracy for the diagnosis of acute appendicitis in pregnant patients beyond the first trimester of pregnancy. Thirty percent of pregnant women with suspected appendicitis are futilely operated. Given the low yield of US, a second-line imaging should be considered in cases of inconclusive US before surgery.

The diagnostic use of magnetic resonance imaging for acute abdominal and pelvic pain in pregnancy

OBJECTIVES

Acute abdomino-pelvic pain in pregnancy represents a diagnostic challenge. In many cases, radiological and laparoscopic diagnostic modalities are hazardous or contraindicated. Magnetic Resonance Imaging (MRI) is not commonly used for this indication and the results are not widely published.

DESIGN AND SETTING

A single-center retrospective observational study.

POPULATION

34 cases of pregnant women with abdomino-pelvic pain who underwent MRI as an additional modality when clinical, laboratory and ultrasound (USS) findings were indeterminate.

METHODS

Case notes were reviewed where pregnant women underwent a MRI investigation for abdominal-pelvic pain. Primary Obstetric indications for an MRI eg placenta accreta were excluded.

MAIN OUTCOME MEASURES

The differential diagnosis after; 1) history and physical examination and 2) with the addition of USS and 3) with the further addition of an MRI were all individually compared to the eventual diagnosis.

RESULTS

The diagnoses reached by MRI corresponded with the final diagnosis in 22 out of 23 cases. In the remaining 11 cases MRI accurately ruled out presence of pathology. MRI was inaccurate in 1 case.

CONCLUSION

The additional use of MRI was more accurate than clinical assessment and USS combined. The accurate exclusion of pathology in 11 cases is particularly significant. MRI should be considered in cases of abdomino-pelvic pain in pregnant women.

Pregnancy and appendicitis: a systematic review and meta-analysis on the clinical use of MRI in diagnosis of appendicitis in pregnant women

Background

The aim of this systematic review and meta-analysis was to evaluate the clinical use of MRI for the evaluation of acute appendicitis during pregnancy.

Methods

The searches were conducted by two independent researchers (MK, MS) to find the relevant studies published from 1/1/2009 until end of 30/12/2018. We searched for published literature in the English language in MEDLINE via PubMed, EMBASETM via Ovid, The Cochrane Library, and Trip database. For literature published in other languages, we searched national databases (Magiran and SID), KoreaMed, and LILACS. The keywords used in the search strategy are Pregnancy [MeSH], Pregnant [MeSH] OR-Magnetic resonance imaging [MeSH] OR-Appendicitis [MeSH] OR-Ultrasound, [MeSH] OR, imaging, MRI [MeSH] OR"،" and Right lower quadrant pain [MeSH]. The risk of bias of every article was evaluated by using QUADAS-2. On the basis of the results from the 2 × 2 tables, pooled measures for sensitivity, specificity, diagnostic odds ratio (DOR), and area under the curves (AUC) along with their 95% confidence intervals (CIs) were calculated using the DerSimonian Lair methodology.

Results

As many as 1164 studies were selected. After analyzing the correspondence of the studies with the required criteria, 19 studies were selected for the final review. For appendicitis in pregnancy, the MRI sensitivity was 91.8% at the 95% confidence interval of (95% CI 87.7-94.9%). At the confidence interval of 95%, the specificity was 97.9% (95% CI 0.97.2-100%). The risk of bias in the studies conducted was measured using the QUADAS-2 tool.

Conclusion

MRI has high sensitivity and specificity (91.8%, 97.9% respectively) for the diagnosis of acute appendicitis in pregnant patients with clinically suspected appendicitis. It is an excellent imaging technique in many instances, which does not expose a fetus, or the mother, to ionizing radiation, making it an excellent option for pregnant patients with suspected acute appendicitis.

Water-enhanced antegrade MR pyelography in pregnancy: a novel radiation-free approach

Our aim was to determine if water-enhanced antegrade magnetic resonance (MR) pyelography can be an alternative to conventional antegrade pyelography in pregnant patients who require percutaneous nephrostomy placement for urosepsis and/or obstructive uropathy. The pregnant patient was placed supine in a 1.5-T MRI scanner seven days after percutaneous nephrostomy placement using ultrasound. Serial axial and coronal T2-weighted echo-planar fast spin-echo sequences were performed before and after injection of the catheter. The right nephrostomy catheter hub was sterilised using chlorhexidine. Sixty millilitres of sterile water were slowly injected. No Gd-based contrast agent was utilised due to safety concerns for the foetus. MR antegrade pyelography demonstrated the level of ureteric obstruction and the absence of renal calculi using sterile water as a contrast medium injected through a percutaneous nephrostomy followed by T2-weighted imaging. Air bubbles in the injected solution were differentiated from calculi due to their mobility on serial scans and their anti-dependent position. Water-enhanced antegrade MR pyelography was a safe and effective method of imaging the pregnant patient. It served as an alternative to conventional antegrade pyelography and minimised potential risks to the foetus.

MRI in pelvic inflammatory disease: a pictorial review

Pelvic inflammatory disease (PID) is an ascending infection of the female genital tract caused by the spread of bacteria from the vagina to the pelvic reproductive organs and occasionally the peritoneum. The most common causative organisms are sexually transmitted. PID is a significant source of morbidity among reproductive age women both as a cause of abdominal pain and as a common cause of infertility. Its clinical presentation is often nonspecific, and the correct diagnosis may first come to light based on the results of imaging studies. MRI is well suited for the evaluation of PID and its complications due to its superior soft tissue contrast and high sensitivity for inflammation. MRI findings in acute PID include cervicitis, endometritis, salpingitis/oophoritis, and inflammation in the pelvic soft tissues. Acute complications include pyosalpinx, tuboovarian abscess, peritonitis, and perihepatitis. Hydrosalpinx, pelvic inclusion cysts and ureteral obstruction may develop as chronic sequela of PID. The pathophysiology, classification, treatment, and prognosis of PID are reviewed, followed by case examples of the appearance of acute and subclinical PID on MR images.

Evolving Practice Patterns in Imaging Pregnant Patients With Acute Abdominal and Pelvic Conditions

OBJECTIVE

The purpose of our study was to determine the current practice patterns of U.S. radiologists in imaging pregnant or potentially pregnant patients with acute abdominal and pelvic conditions.

MATERIALS AND METHODS

After obtaining an Institutional Review Board waiver, all members of the Association of University Radiologists, the Association of Program Directors in Radiology, and the Society of Radiologists in Ultrasound were invited via e-mail to take a 23-question online survey on radiology practices and clinical scenarios about acute abdominal and pelvic imaging of pregnant patients.

RESULTS

Comparisons were made with previously published surveys. A total of 225 responses were received. Areas of high consensus included pregnancy assessment (97%) and obtaining informed consent (87%) before imaging, having a written policy on imaging pregnant patients (79%), modification of computed tomography (CT) protocols (74%), avoiding gadolinium contrast in magnetic resonance imaging (MRI) (74%), using ultrasound for initial imaging in some scenarios, and using CT in trauma cases after inconclusive ultrasound. Areas of emerging consensus compared to 2007 included the use of serum or urine testing to confirm pregnancy status (59.4%; previously 14%) and the use of MRI in suspected appendicitis after an inconclusive ultrasound (73% in first trimester and 67% in third trimester; previously 46% and 29%, respectively). Areas without clear consensus included policy development, additional modifications to MRI protocols, choice of imaging modality, radiation dose, and the use of contrast agents in some scenarios.

CONCLUSION

In conclusion, high or increasing consensus exists in some areas of imaging pregnant patients with acute abdominal and pelvic conditions, but has yet to emerge in other areas.

A Systematic Review and Meta-Analysis of Diagnostic Performance of MRI for Evaluation of Acute Appendicitis

OBJECTIVE

A meta-analysis was performed to determine the accuracy of MRI in the diagnosis of acute appendicitis in the general population and in subsets of pregnant patients and children.

MATERIALS AND METHODS

A systematic search of the PubMed and EMBASE databases for articles published through the end of October 2014 was performed to identify studies that used MRI to evaluate patients suspected of having acute appendicitis. Pooled data for sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

A total of 30 studies that comprised 2665 patients were reviewed. The sensitivity and specificity of MRI for the diagnosis of acute appendicitis are 96% (95% CI, 95-97%) and 96% (95% CI, 95-97%), respectively. In a subgroup of studies that focused solely on pregnant patients, the sensitivity and specificity of MRI were 94% (95% CI, 87-98%) and 97% (95% CI, 96-98%), respectively, whereas in studies that focused on children, sensitivity and specificity were found to be 96% (95% CI, 95-97%) and 96% (95% CI, 94-98%), respectively.

CONCLUSION

MRI has a high accuracy for the diagnosis of acute appendicitis, for a wide range of patients, and may be acceptable for use as a first-line diagnostic test.

Magnetic resonance imaging - A troubleshooter in obstetric emergencies: A pictorial review

The application of magnetic resonance imaging (MRI) in pregnancy faced initial skepticism of physicians because of fetal safety concerns. The perceived fetal risk has been found to be unwarranted and of late, the modality has attained acceptability. Its role in diagnosing fetal anomalies is well recognized and following its safety certification in pregnancy, it is finding increasing utilization during pregnancy and puerperium. However, the use of MRI in maternal emergency obstetric conditions is relatively limited as it is still evolving. In early gestation, ectopic implantation is one of the major life-threatening conditions that are frequently encountered. Although ultrasound (USG) is the accepted mainstay modality, the diagnostic predicament persists in many cases. MRI has a role where USG is indeterminate, particularly in the extratubal ectopic pregnancy. Later in gestation, MRI can be a useful adjunct in placental disorders like previa, abruption, and adhesion. It is a good problem-solving tool in adnexal masses such as ovarian torsion and degenerated fibroid, which have a higher incidence during pregnancy. Catastrophic conditions like uterine rupture can also be preoperatively and timely diagnosed. MRI has a definite role to play in postpartum and post-abortion life-threatening conditions, e.g., retained products of conception, and gestational trophoblastic disease, especially when USG is inconclusive or inadequate.

Magnetic Resonance Imaging of Abdominal and Pelvic Pain in the Pregnant Patient

The utility of MR imaging in evaluating abdominal and pelvic pain in the pregnant patient is discussed. Details regarding the indications, technical aspects, and imaging findings of various common abdominal and pelvic abnormalities in pregnancy are reviewed.

Evaluating Patients with Left Upper Quadrant Pain

Imaging plays a major role in the evaluation of patients who present to the emergency department with acute left upper quadrant (LUQ) pain. Multidetector computed tomography is currently the primary modality used for imaging these patients. The peritoneal reflections, subperitoneal compartment, and peritoneal spaces of the LUQ are key anatomic features in understanding the imaging appearance of acute diseases in this area. Diseases of the stomach, spleen, pancreas, and splenic flexure are encountered in patients with acute LUQ pain. Optimization of the imaging protocol is vital for accurate diagnosis and characterization of these diseases in the acute setting.

[Protection of the unborn child in diagnostic and interventional radiological procedures]

The radiation exposure of an unborn child should be principally avoided, whenever it is medically reasonably possible; therefore, the identification of pregnant patients is the first and the most important step in radiation protection of the unborn child. However, in cases of emergency saving the life of the patient has a higher priority than the radiation protection of the unborn child. In this review article, we present a longitudinal section through the national and international literature and guidelines as a basis for radiological management of a (possibly) pregnant patient. We also list some radiological procedures recommended in the literature for a series of maternal indications considering the contraindications of each method during pregnancy and radiation protection of the unborn child.

A 23-year, single-center, retrospective analysis of 36 cases of acute pancreatitis in pregnancy

OBJECTIVE

To assess the incidence, causes, clinical characteristics, and outcomes of cases of acute pancreatitis in pregnancy (APIP).

METHODS

A retrospective review was conducted of the medical records of pregnant women who were diagnosed with APIP at any point during pregnancy, labor, or the puerperium and attended Beijing Chaoyang Hospital, China, between January 1, 1991, and March 31, 2014.

RESULTS

Among 34 292 pregnant women admitted to the center during the study period, 36 patients were diagnosed with APIP. The condition developed during the second (9 [25%] cases) and third (22 [61%]) trimesters. The underlying cause was hypertriglyceridemia for 14 (39%) patients and biliary diseases for 7 (19%). Severe acute pancreatitis was significantly more common among patients with hypertriglyceridemia (11/14 [79%]) than among those without hypertriglyceridemia (6/22 [27%]; P=0.006). Additionally, complications were recorded for more patients with hypertriglyceridemia (11 [79%]) than those without hypertriglyceridemia (4 [18%]; P<0.001). Delayed diagnosis was more common among patients with severe acute pancreatitis (8/17 [47%]) than among those with mild acute pancreatitis (3/19 [16%]; P=0.039). No maternal deaths and only two perinatal deaths were recorded.

CONCLUSION

The overall incidence of APIP was low; however, hypertriglyceridemia was associated with poor outcomes. Early diagnosis and prompt treatment should be implemented to improve maternal and fetal prognosis and decrease mortality.

Loss of renal India ink artifact-a useful radiological sign for obstructive hydronephrosis in pregnancy

Magnetic resonance imaging is a useful tool for investigating causes of abdominal pain in pregnancy. Differentiating between physiologic hydronephrosis of pregnancy and pathologic hydronephrosis can be challenging for clinicians and radiologists. This report describes loss of the India ink artifact around the obstructed kidney as a novel and potentially useful radiological sign, which may be of value in the evaluation of abdominal pain and hydronephrosis in pregnancy.

Imaging for acute pelvic pain in pregnancy

Acute pelvic pain in pregnancy presents diagnostic and therapeutic challenges. Standard imaging techniques need to be adapted to reduce harm to the foetus from X-rays because of their teratogenic and carcinogenic potential. Ultrasound remains the primary imaging investigation of the pregnant abdomen. Magnetic resonance imaging (MRI) has been shown to be useful in the diagnosis of gynaecological and obstetric problems during pregnancy and in the setting of acute abdomen during pregnancy. MRI overcomes some of the limitations of ultrasound, mainly the size of the gravid uterus. MRI poses theoretical risks to the foetus and care must be taken to minimise these with the avoidance of contrast agents. Teaching Points • Ultrasound and MRI are the preferred investigations for acute pelvic pain during pregnancy. • Ultrasound remains the primary imaging investigation because of availability and portability. • MRI helps differentiate causes of acute pelvic pain when ultrasound is inconclusive.

Diagnosis of a sigmoid volvulus in pregnancy: ultrasonography and magnetic resonance imaging findings

Sigmoid volvulus complicating pregnancy is a rare, non-obstetric cause of abdominal pain that requires prompt surgical intervention (decompression) to avoid intestinal ischemia and perforation. We report the case of a 31-week pregnant woman with abdominal pain and subsequent development of constipation. Preoperative diagnosis was achieved using magnetic resonance imaging and ultrasonography: the large bowel distension and a typical whirl sign - near a sigmoid colon transition point - suggested the diagnosis of sigmoid volvulus. The decision to refer the patient for emergency laparotomy was adopted without any ionizing radiation exposure, and the pre-operative diagnosis was confirmed after surgery. Imaging features of sigmoid volvulus and differential diagnosis from other non-obstetric abdominal emergencies in pregnancy are discussed in our report, with special emphasis on the diagnostic capabilities of ultrasonography and magnetic resonance imaging.

Acute pancreatitis during pregnancy: a review

This article aims to draw together recent thinking on pregnancy and acute pancreatitis (AP), with a particular emphasis on pregnancy complications, birth outcomes and management of AP during pregnancy contingent on the etiology. AP during pregnancy is a rare but severe disease with a high maternal-fetal mortality, which has recently decreased thanks to earlier diagnosis and some maternal and neonatal intensive care improvement. AP usually occurs during the third trimester or the early postpartum period. The most common causes of AP are gallstones (65 to 100%), alcohol abuse and hypertriglyceridemia. Although the diagnostic criteria for AP are not specific for pregnant patients, Ranson and Balthazar criteria are used to evaluate the severity and treat AP during pregnancy. The fetal risks from AP during pregnancy are threatened preterm labor, prematurity and in utero fetal death. In cases of acute biliary pancreatitis during pregnancy, a consensual strategy could be adopted according to the gestational age, and taking in consideration the high risk of recurrence of AP (70%) with conservative treatment and the specific risks of each treatment. This could include: conservative treatment in first trimester and laparoscopic cholecystectomy in second trimester. During the third trimester, conservative treatment or endoscopic retrograde cholangiopancreatography with biliary endoscopic sphincterotomy, and laparoscopic cholecystectomy in early postpartum period are recommended. A multidisciplinary approach, including gastroenterologists and obstetricians, seems to be the key in making the best choice for the management of AP during pregnancy.

MR imaging of the placenta: what a radiologist should know

Imaging of the placenta can have a profound impact on patient management, owing to the morbidity and mortality associated with various placental conditions. Placental conditions affecting the mother and fetus include molar pregnancies, placental hematoma, abruption, previa, accreta, vasa previa, chorioangioma, and retained products of conception. Although uncommon, abnormalities of the placenta are important to recognize owing to the potential for maternal and fetal morbidity and mortality. Sonography remains the first imaging modality for evaluation of the placenta. Magnetic resonance (MR) imaging has many unique properties that make it well-suited for imaging of the placenta: the multi-planar capabilities, the improved tissue contrast that can be obtained using a variety of pulse sequences and parameters and the lack of ionizing radiation; MR imaging can be of added diagnostic value when further characterization is required. In this article, we review the appearances and the role of MRI in diagnosis and management of these conditions. We present our clinical perspective on diagnosing these challenging problems with MRI and review the imaging findings that can lead to a correct diagnosis.

APPENDICITIS IN PREGNANCY

Acute appendicitis is the most common non-obstetric indication for surgical intervention in pregnancy, complicating 1/500 to 1/2000 deliveries. Due to the anatomical and physiological changes associated with pregnancy, appendicitis may present a diagnostic dilemma, leading to management delays and thus increasing the risk of appendiceal perforation. Many of the common presenting symptoms of appendicitis are common features of normal pregnancy including lower abdominal pain, nausea, vomiting and leukocytosis. Furthermore, the enlarging gravid uterus may displace the appendix to varying degrees thus altering the classic symptom pattern of appendicitis. The often nonspecific presentation in pregnancy may necessitate the utilization of diagnostic imaging to aid in accurate diagnosis. However, the perforated appendix is the most common surgical cause of fetal loss and the time required for any diagnostic aid must be weighed against the increasing risk of perforation caused by delay in surgical intervention.

The use of pre-operative computed tomography in the assessment of the acute abdomen

INTRODUCTION

While there are a lot of data on the accuracy of computed tomography (CT) in diagnosing specific causes of an acute abdomen, there is very little information on the accuracy of CT in the acute general surgical admissions workload. We look at the diagnostic accuracy of CT in patients presenting with an acute abdomen who ultimately required a laparotomy.

METHODS

Patients who underwent an emergency laparotomy between 2008 and 2010 at Eastbourne District General Hospital with pre-operative CT on the same admission were included in the study. The CT report was compared with the laparotomy and histology findings and, where a discrepancy existed, the original imaging was reviewed by a senior consultant blinded to the original report and laparotomy findings.

RESULTS

A total of 196 emergency laparotomies were performed over the 2-year period, with 112 patients undergoing preoperative CT. Fifteen patients were excluded from the study due to missing notes. In the remaining 97 patients, 80 CT reports correlated with the final operative diagnosis, giving a diagnostic accuracy of 82%. Of these, the on-call registrar was the initial reporter in 37 scans, with a diagnostic accuracy of 78%. On review of the CT by a second consultant, this increased to 90 correlations, yielding an accuracy of 93%. Delay between CT and the operation did not significantly alter diagnostic accuracy, nor was there any statistically significant reduction in accuracy in reports issued by on-call registrars.

CONCLUSIONS

On first reporting, CT misses 18% of diagnoses that ultimately require operative intervention. Reducing the threshold for obtaining a second consultant radiologist review significantly improves the diagnostic accuracy to 93%.

Acute antepartum pyelonephritis in pregnancy: a critical analysis of risk factors and outcomes

OBJECTIVE

To test the incidence and sonographic parameters of pyelonephritis during pregnancy, and to examine risk factors and pregnancy outcomes of women with acute antepartum pyelonephritis.

STUDY DESIGN

A retrospective population-based study comparing all singleton pregnancies of patients with and without acute antepartum pyelonephritis was performed. Patients lacking prenatal care as well as multiple gestations were excluded from the study. Multiple logistic regression models were used to control for confounders.

RESULTS

Out of 219,612 singleton deliveries in 1988-2010, 165 women (0.07%) suffered from acute antepartum pyelonephritis. Abnormal sonographic findings were found in 85.7% of the patients with pyelonephritis. Pyelonephritis was significantly associated with nulliparity (46.1% vs. 24.4%, p<0.001), younger maternal age (26.3 ± 6.0 vs. 28.6 ± 5.8 years, p<0.001), intrauterine growth restriction (IUGR) (6.7% vs. 2.1%, p<0.001), placental abruption (3.6% vs. 0.7%, p<0.001), low 1 min Apgar scores (10.3% vs. 6.0%, p<0.05), urinary tract infection (UTI) (4.2% vs. 0.4%, p<0.001) and preterm delivery (less than 37 weeks gestation; 20.0% vs. 7.8%; p<0.001). Using a multivariable analysis, independent risk factors for acute antepartum pyelonephritis were nulliparity (OR 2.0; 95% C.I 1.4-2.9; p<0.001), UTI (OR 10.3; 95% C.I 4.8-22.1; p<0.001) and younger maternal age (OR 0.96; 95% C.I 0.93-0.99; p=0.009). Using another multivariable analysis, with preterm delivery as the outcome variable, acute antepartum pyelonephritis was found as an independent risk factor for preterm delivery (OR 2.6; 95% C.I 1.7-3.9; p<0.001).

CONCLUSION

Acute antepartum pyelonephritis is associated with adverse perinatal outcomes and specifically is an independent risk factor for preterm delivery.