Magnetic resonance imaging for the evaluation of acute abdominal pain in pregnancy

The Management of Symptomatic Hydronephrosis in Pregnancy

The aim of this article is to provide a literature review on the management of symptomatic physiological hydronephrosis in pregnancy and compare different modalities of intervention when needed. In this review, we conducted an electronic literature search of peer-reviewed journal articles. The PubMed, Research Gate, and Google Scholar databases were queried with the following search terms: "pregnancy", "obstruction," and "hydronephrosis"; the terms "urolithiasis" and "kidney stone" were excluded. As a result, conservative treatment was successful and more favored for most of the patients and the clinicians in the different studies we found. Conservative management will usually include regular analgesia, positioning, and antibiotics. Close follow-up with ultrasound is always recommended. Intervention with ureteric stent insertion or nephrostomy tube insertion was less favored and only triggered by certain clinical criteria. In conclusion, symptomatic hydronephrosis in pregnancy can be safely treated conservatively. However, ureteral double-J stenting or percutaneous nephrostomy are effective and safe treatment methods in the minority of patients with persistent symptoms not responding to conservative management.

Role of Abdominal Ultrasound and Magnetic Resonance Imaging in Pregnant Women Presenting With Acute Abdominal Pain

Background and Purpose: Abdominal pain during pregnancy is quite common; however, surgical pathology such as acute appendicitis as a cause of such pain is not. Diagnostic tests used in addition to history and physical examination (PE) are ultrasound (US) and magnetic resonance imaging (MRI). We elected to find the role of these tests in pregnant patients who presented to our emergency department with acute abdominal pain.Materials And Methods: Retrospective analysis of 136 pregnant women with acute abdominal pain presented to the emergency department (ED). We reviewed PE, US, MRI, gestational age, comorbid conditions, and length of stay. Statistical analysis was done using student's t-test and chi-square test. Institutional review board approval was obtained.Results: Mean age was 26 (±4.6) and the mean gestational age was 24 (±9.9) weeks. Of those patients, there were 81 patients who had an US and MRI performed. The US was positive in 16 patients, while the MRI was positive in 25 patients. Three patients went for appendectomy. The US sensitivity was 0% and specificity 79%. Positive predictive value for US was 0% and negative predictive value was 95%, which was less than 100%. The MRI likelihood ratios were calculated for each test's clinical application and demonstrated that the US test result was indeterminate for ruling in and for ruling out appendicitis while the MRI allowed for high ability to rule out the disease.Conclusion: In pregnant women with acute abdominal pain and a positive PE highly suggestive of surgical pathology, US had limited value and patients should proceed to MRI.

Computed Tomography Features of Adnexal Torsion: A Meta-Analysis

OBJECTIVES

We performed a meta-analysis of studies examining the computed tomography (CT) features of adnexal torsion (AT).

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Library for studies involving the proportion of CT features in patients with AT and that used surgery as the reference test. Study quality was assessed using the Newcastle-Ottawa scale and the Agency for Healthcare Research and Quality tool.

RESULTS

Twelve articles involving 483 patients were included. The pooled proportion of right-sided adnexal lesion was 54% (95% confidence interval [CI]: 49%-56%). The pooled proportions of the ovarian lesion histopathological types were: benign germ cell tumors, 33% (95% CI: 28%-37%); benign cystic lesions, 26% (95% CI: 21%-30%); benign epithelial neoplasms, 24% (95% CI: 20%-29%); sex cord-stromal tumors, 4% (95% CI: 2%-6%); borderline neoplasms, 3% (95% CI: 1%-6%); and hemorrhagic cysts, 2% (95% CI: 0%-3%). The pooled proportions of CT features were: Adnexal enlargement, 99% (95% CI: 98%-99%); adnexal with mass, 98% (95% CI: 97%-100%); twisted pedicle, 81% (95% CI: 78%-83%); mass with thickened wall, 77% (95% CI: 73%-81%); tubal thickening, 73% (95% CI: 68%-77%); abnormal location of adnexa, 69% (95% CI: 63%-75%), pelvic ascites, 43% (95% CI: 38%-49%); pelvic fat infiltration, 41% (95% CI: 34%-48%); uterine deviation, 37% (95% CI: 31%-42%); and lack of enhancement, 20% (95% CI: 14%-25%).

CONCLUSION

Adnexal enlargement, adnexal mass, and twisted pedicle may be the most important CT features for diagnosing AT.

Problem-solving with MRI in acute abdominopelvic conditions, part 2: gynecological, obstetric, vascular, and renal diseases

The purpose of this article is to illustrate the benefits of magnetic resonance imaging (MRI) in the setting of abdominopelvic emergencies. Owing to intrinsically high soft-tissue contrast resolution, and ability to resolve different soft tissue, MRI holds notable advantages over other imaging modalities and can be used as a problem-solving tool. Additional advantages of MRI include lack of radiation-related risks to children and pregnant women, and the ability to acquire detailed diagnostic information even without intravenous contrast which can be beneficial in patients with contrast allergy and end-stage renal disease. In the part 2, the authors focus on MRI features of female pelvic gynecological diseases, pregnancy- related complications, abdominal vascular complications, and renal diseases.

Optimization of pulse sequences in ultrafast magnetic resonance imaging for the diagnosis of acute abdominal pain caused by gastrointestinal disease

Background

Magnetic resonance imaging (MRI) is widely used to diagnose acute abdominal pain; however, it remains unclear which pulse sequence has priority in acute abdominal pain.

Purpose

To investigate the diagnostic accuracy of MRI and to assess the conspicuity of each pulse sequence for the diagnosis of acute abdominal pain due to gastrointestinal diseases

Material and Methods

We retrospectively enrolled 60 patients with acute abdominal pain who underwent MRI for axial and coronal T2-weighted (T2W) imaging, fat-suppressed (FS)-T2W imaging, and true-fast imaging with steady-state precession (True-FISP) and axial T1-weighted (T1W) imaging and investigated the diagnosis with endoscopy, surgery, histopathology, computed tomography, and clinical follow-up as standard references. Two radiologists determined the diagnosis with MRI and rated scores of the respective sequences in assessing intraluminal, intramural, and extramural abnormality using a 5-point scale after one month. Diagnostic accuracy was calculated and scores were compared by Wilcoxon-signed rank test with Bonferroni correction.

Results

Diagnostic accuracy was 90.0% and 93.3% for readers 1 and 2, respectively. Regarding intraluminal abnormality, T2W, FS-T2W, and True-FISP imaging were superior to T1W imaging in both readers. FS-T2W imaging was superior to True-FISP in reader 2 (P < 0.0083). For intramural findings, there was no significant difference in reader 1, whereas T2W, FS-T2W, and True-FISP imaging were superior to T1W imaging in reader 2 (P < 0.0083). For extramural findings, FS-T2W imaging was superior to T2W, T1W, and True-FISP imaging in both readers (P < 0.0083).

Conclusion

T2W and FS-T2W imaging are pivotal pulse sequences and should be obtained before T1W and True-FISP imaging.

Bowel obstruction: a narrative review for all physicians

Small and large bowel obstructions are responsible for approximately 15% of hospital admissions for acute abdominal pain in the USA and ~ 20% of cases needing acute surgical care. Starting from the analysis of a common clinical problem, we want to guide primary care physicians in the initial management of a patient presenting with acute abdominal pain associated with intestinal obstruction.

Use of pre-operative imaging for symptomatic uterine myomas during pregnancy: a case report and a systematic literature review

PURPOSE

Uterine fibroids (UFs) occur in 10% of pregnancies and may lead to severe maternal-fetal complications, mainly depending on UFs characteristics and the distance to the uterine cavity (UC). When symptomatic, UFs are managed medically. Nevertheless, in about 2% of cases, surgery becomes necessary. Entry into the UC should be avoided during myomectomy. Consequentially, pre-operative assessment of this risk could be beneficial. Ultrasonography (US) represents the gold standard for UFs assessment; however, scarce evidence has been produced to assess the role of magnetic resonance imaging (MRI). The aim of the present study was to summarize current evidence about the pre-operative use of imaging techniques for UFs during pregnancy.

METHODS

A systematic research of the literature was conducted in Scopus, PubMed/MEDLINE, ScienceDirect and the Cochrane Library, including case reports and case series. A case report was also discussed. We collected data regarding patients, imaging assessment, UFs characteristics, surgical information, timing and modality of delivery.

RESULTS

According to our search strategy, 66 articles were selected and 210 patients were included. US assessment was reported in 36 (17%) cases. MRI was reported in 10 (4.7%) cases. Only in one case, MRI was used to measure the distance between UFs and UC.

CONCLUSION

US allows an adequate pre-operative evaluation of anterior, submucosal or pedunculated symptomatic UFs in pregnancy. However, compared to US, MRI may provide a more accurate evaluation of multiple, large, intramural or posterior UFs and could measure the distance between UFs and UC more accurately.

Clinical use of MRI for the evaluation of acute appendicitis during pregnancy

PURPOSE

The purpose of this study was to determine the diagnostic accuracy of MRI for detecting acute appendicitis in pregnancy in a multi-institution study involving general body MR readers with no specific expertise in MR imaging of the pregnant patient.

METHODS

Retrospective review of MRI examinations on PACS in 42 pregnant patients was evaluated for acute right lower quadrant pain. Three fellowship-trained general body radiologists analyzed the MRI examinations in consensus and attempted to localize the appendix, assess for features of appendicitis, and exclude alternative etiologies for the right lower quadrant pain.

RESULTS

Of the 42 MRI examinations, the readers noted 6 cases of acute appendicitis, 16 cases of a normal appendix, and 20 cases involving non-visualization of the appendix but where there were no secondary features of acute appendicitis. Based on the surgical data and clinical follow-up, there were 3 true-positive cases, 3 false-positive cases, 34 true-negative cases, and 2 false-negative cases of acute appendicitis on MRI. This yielded an accuracy of 88.1%, sensitivity of 60%, specificity of 91.9%, positive predictive value of 50%, and negative predictive value of 94.4% for the detection of acute appendicitis in the pregnant patient on MRI. Alternative etiologies for the right lower quadrant pain on MRI included torsion of an ovarian dermoid in 1 case and pyelonephritis in 1 case.

CONCLUSION

MRI is an excellent modality for excluding acute appendicitis in pregnant patients presenting with right lower quadrant pain.

CT features in surgically proven cases of ovarian torsion-a pictorial review

Ovarian torsion is a surgical emergency characterized by a partial or complete rotation of the ovarian vascular pedicle, causing obstruction to venous outflow followed by arterial inflow. Clinically, ovarian torsion frequently mimics other causes of acute pelvic pain such as appendicitis, diverticulitis, renal colic etc. Ultrasonography is the first-line imaging modality of choice for evaluation of ovarian torsion. MRI is useful as a problem-solving tool in patients with equivocal or non-diagnostic ultrasonography studies. CT is ordinarily not utilized in a young female with suspected ovarian torsion due to the radiation dose. However, the significant expansion in use of CT imaging in emergency departments for female patients presenting with acute abdominal pain has increased the likelihood that ovarian torsion may be first seen on CT. In addition, a non-specific clinical presentation may lead to an initial imaging with CT rather than ultrasonography. Ultrasound features of the ovarian torsion are well known and sufficiently described across literature as compared with the CT scan findings. In view of the increasing usage of CT as the modality of choice in emergency settings, it is imperative for the radiologist to familiarize with the CT features of ovarian torsion. An early correct diagnosis by the radiologist in clinically unsuspected cases, facilitating a prompt surgery to restore the ovarian blood flow can prevent permanent irreversible damage. There is limited published data available on the CT features of ovarian torsion. This pictorial essay illustrates CT findings with histological correlation of surgically proven ovarian torsion in our institution. These patients were primarily investigated with CT scan for acute pelvic pain ascribed to non-gynaecological causes such as bowel or urinary tract lesions.

T1 bright appendix sign to exclude acute appendicitis in pregnant women

OBJECTIVE

To evaluate the diagnostic value of the T1 bright appendix sign for the diagnosis of acute appendicitis in pregnant women.

MATERIAL AND METHODS

This retrospective study included 125 pregnant women with suspected appendicitis who underwent magnetic resonance (MR) imaging. The T1 bright appendix sign was defined as a high intensity signal filling more than half length of the appendix on T1-weighted imaging. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the T1 bright appendix sign for normal appendix identification were calculated in all patients and in those with borderline-sized appendices (6-7 mm).

RESULTS

The T1 bright appendix sign was seen in 51% of patients with normal appendices, but only in 4.5% of patients with acute appendicitis. The overall sensitivity, specificity, PPV, and NPV of the T1 bright appendix sign for normal appendix diagnosis were 44.9%, 95.5%, 97.6%, and 30.0%, respectively. All four patients with borderline sized appendix with appendicitis showed negative T1 bright appendix sign.

CONCLUSION

The T1 bright appendix sign is a specific finding for the diagnosis of a normal appendix in pregnant women with suspected acute appendicitis.

KEY POINTS

• Magnetic resonance imaging is increasingly used in emergency settings. • Acute appendicitis is the most common cause of acute abdomen. • Magnetic resonance imaging is widely used in pregnant population. • T1 bright appendix sign can be a specific sign representing normal appendix.

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.

Intestinal malrotation complicated by an occlusive syndrome involving internal hernia in a pregnant woman

We present the case of a 33-year-old female who presented intestinal obstruction at the 7th month of pregnancy. She was complaining of abdominal pain with paroxysms, nausea and vomiting. When the symptoms worsened, we performed a CT-scan, which revealed suspected intestinal obstruction in a context of intestinal malrotation (IM). Conservative therapy failed and she required emergency laparotomy beginning with a caesarean section. The surgery revealed a peritoneal defect due to the IM through which the jejunum and ileum were incarcerated and strangulated. The incarcerated bowel was reduced and intestinal colour quickly returned to normal. Primary closure of the peritoneal defect was thus performed and the post-operative course was uneventful for the mother and the baby, who was admitted to the neonatal intensive care unit.

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.

Bowel Obstruction

Small bowel obstruction and large bowel obstruction account for approximately 20% of cases of acute abdominal surgical conditions. The role of the radiologist is to answer several key questions: Is obstruction present? What is the level of the obstruction? What is the cause of the obstruction? What is the severity of the obstruction? Is the obstruction simple or closed loop? Is strangulation, ischemia, or perforation present? In this presentation, the radiologic approach to and imaging findings of patients with known or suspected bowel obstruction are presented.

Magnetic resonance imaging of acute abdominal and pelvic pain in pregnancy

Evaluation of acute abdominal and pelvic pain in pregnancy presents a diagnostic challenge for clinicians and radiologists alike. The differential diagnosis includes obstetric and nonobstetric conditions unique to pregnancy, in addition to causes of acute abdominal and pelvic pain unrelated to the pregnancy. The clinical presentation and course of disease may be altered in pregnancy, and several pathologies are exacerbated by pregnancy. Discriminating clinical features in the diagnosis of abdominal and pelvic pain are often confounded by expected anatomic and physiologic changes in pregnancy. Moreover, while diagnostic pathways may be altered in pregnancy, the necessity for a timely and accurate diagnosis must be underscored, as delay in treatment may result in an undesirable increase in morbidity and/or mortality for both the patient and fetus. Advances in magnetic resonance imaging (MRI) through faster acquisition and motion-insensitive techniques, coupled with increased awareness and education regarding the value of MRI in diagnosing a wide range of pathology, have established MRI as a valuable strategy in the investigation of acute abdominal and pelvic pain in the pregnant patient. This review presents a practical approach to common obstetric and nonobstetric causes of acute abdominal and pelvic pain during pregnancy, as well as safety considerations for performing MRI in this patient population.

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.

Location of the appendix at the third trimester of pregnancy: A new approach to old dilemma

The aim of this study was to determine the location of the appendix at the third trimester of pregnancy as there are conflicting results in literature. Distances from the base of the appendix were measured intra-operatively to the anterior iliac spine (A), symphysis pubis (B) and the xyphoid process (C). The same measurements were taken from McBurney's point on the abdominal wall (A1, B1 and C1). In the allocated 21 pregnant and 18 non-pregnant women, distance A and B were 10.3 ± 0.9 cm and 18.3 ± 3.2 cm in pregnant and 6.7 ± 0.9 cm and 13.2 ± 0.9 cm in non-pregnant women (p < 0.001), respectively. Distance C was shorter in pregnant women (14.7 ± 2.5 cm vs. 23.8 ± 1.9, p < 0.001). Conversely, distance C1 was longer in pregnant women (30.3 ± 3.0 vs. 24.8 ± 5.1 cm, p = 0.004). This study provides evidence that the appendix moves cranially late in the course of the pregnancy. Therefore, McBurney's point cannot be used as a reference point to localise the appendix at the third trimester of pregnancy.

MRI: is there a role in obstetrics?

Magnetic resonance imaging has a complementary role in obstetrical imaging to ultrasound (US). Although US has advantages as an initial imaging technique, there are significant numbers of patients who cannot be adequately evaluated for a variety of reasons including calvarial calcification, oligoanhydramnios, or simply obesity. MR can provide additional information that cannot be obtained by US and is invaluable in central nervous system anomaly evaluation, airway management, and planning for postnatal intervention. Newer techniques established in the postnatal population such as spectroscopy, diffusion-weighted imaging, and functional imaging have future applications in the fetus.