A 10-year restrospective evaluation of ultrasound in pregnant abdominal trauma patients.

The pregnant abdominal trauma patient presents a unique diagnostic challenge. This study aimed to evaluate the accuracy of abdominal sonography for the detection of clinically important injuries in pregnant abdominal trauma patients. A retrospective review was performed of a trauma center database from 2001 to 2011. Medical records were reviewed to determine initial abdominal imaging test results and clinical course. Sensitivity, specificity, positive predictive value, and negative predictive value of ultrasound for detection of traumatic injury were calculated. Of 19,128 patients with suspected abdominal trauma, 385 (2 %) were pregnant. Of these, 372 (97 %) received ultrasound as the initial abdominal imaging test. All 13 pregnant patients who did not receive ultrasound received abdominal CT. Seven pregnant patients underwent both ultrasound and CT. Seven ultrasound examinations were positive, leading to one therapeutic Cesarean section and one laparotomy. One ultrasound was considered false positive (no injury was seen on subsequent CT). There were 365 negative ultrasound examinations. Of these, 364 were true negative (no abdominal injury subsequently found). One ultrasound was considered false negative (a large fetal subchorionic hemorrhage seen on subsequent dedicated obstetrical ultrasound). Sensitivity and positive predictive value were 85.7 %. Specificity and negative predictive value were 99.7 %. Abdominal sonography is an effective and sufficient imaging examination in pregnant abdominal trauma patients. When performed as part of the initial assessment using an abbreviated trauma protocol with brief modifications for pregnancy, ultrasound minimizes diagnostic delay, obviates radiation risk, and provides high sensitivity for injury in the pregnant population.

Multifocal intravascular papillary endothelial hyperplasia in the retroperitoneum and spine: a case report and review of the literature.

The authors present a unique case of intravascular papillary endothelial hyperplasia (IPEH) localized in the renal hilum, retroperitoneum, and spine in a patient with Wegener granulomatosis. IPEH rarely occurs in the abdomen or spine with few cases reported in the literature. No case has been reported of IPEH involving both the retroperitoneum and spine. In our case, MR imaging revealed enhancing masses in the right renal hilum and retroperitoneum as well as multiple focal enhancing lesions throughout the spine with lower thoracic ventral thecal sac compression. The diagnosis was established by resection of the renal hilum mass, and interval follow-up is deemed necessary for the remaining lesions because the long-term evolution of IPEH with conservative treatment alone is not well established.

Imaging acute appendicitis.

Acute appendicitis is the most common entity requiring emergent abdominal surgery. Early diagnosis is critical to proper management. Patients often present with a classic clinical picture and may not require imaging, although many patients have nonspecific signs and symptoms. It is in these cases that imaging plays a large role. Imaging options include computed tomography, ultrasound, and magnetic resonance. The following discussion addresses the different imaging modality options with regard to diagnostic performance, indications, and interpretation in patients with suspected acute appendicitis.

Polycystic ovary syndrome: clinical and imaging features.

Polycystic ovary syndrome is the most common endocrine disorder occurring in reproductive-age women. The syndrome is complex, multifactorial, and not always easily defined. Diagnosis is based upon a combination of clinical and biochemical criteria and ovarian morphology. The following review describes the clinical features, pathophysiology, diagnosis, and the role of imaging. Diagnostic imaging techniques are discussed, with emphasis on ultrasound as the main modality used worldwide. Contributions of 3-dimensional and Doppler ultrasound are addressed in addition to potential indications for magnetic resonance imaging in the evaluation of patients with suspected polycystic ovary syndrome.

Cross-sectional imaging of extranodal involvement in abdominopelvic lymphoproliferative malignancies.

Extranodal lymphoproliferative diseases are common, and their prevalence is increasing. Non-Hodgkin lymphomas and Hodgkin disease, in particular, frequently involve extranodal structures in the abdomen and pelvis, including both the solid organs (liver, spleen, kidneys, and pancreas) and the hollow organs of the gastrointestinal tract. Because virtually any abdominopelvic tissue may be involved, many different imaging manifestations are possible, and lymphoproliferative diseases may mimic other disorders. Familiarity with the imaging manifestations that are diagnostically specific for extranodal lymphoproliferative diseases is important because imaging plays an important role in the noninvasive management of disease. However, a definitive diagnosis requires a biopsy (of bone marrow, a lymph node, or a mass), a peripheral blood analysis, and other laboratory tests. In patients with known disease, the goals of imaging are staging, evaluation of response to therapy, and identification of new or recurrent disease or of complications of therapy. In patients without known disease, imaging permits a provisional diagnosis.

MR contrast agents for liver imaging: what, when, how.

The major classes of contrast agents currently used for magnetic resonance (MR) imaging of the liver include extracellular agents (eg, low-molecular-weight gadolinium chelates), reticuloendothelial agents (eg, ferumoxides), hepatobiliary agents (eg, mangafodipir), blood pool agents, and combined agents. Mechanisms of action, dosage, elimination, toxic effects, indications for use, and MR imaging technical considerations vary according to class. Gadolinium chelates are the most widely used. Ferumoxides are a useful adjunct for detection of hepatocellular carcinoma, particularly when used in combination with gadolinium to achieve improved lesion-to-liver contrast over that achievable with gadolinium alone. Mangafodipir is a prototype hepatobiliary agent that is taken up by lesions with functioning hepatocytes. It may be used for MR cholangiography as well as liver imaging. Although mangafodipir is no longer commercially available in the United States, it is currently marketed and used in Europe. Blood pool agents have not yet been approved for human use in the United States. However, a new combined MR contrast agent, gadobenate dimeglumine, recently was approved, and other agents are in various stages of development.

Future directions in MR imaging of the female pelvis.

New technology continues to change the field of MR imaging. This article describes select areas of technical development that are likely to have an increasing clinical impact on MR imaging of the female pelvis, including high-field imaging, parallel imaging, contrast agents, diffusion-weighted imaging and spectroscopy, and MR-guided intervention.

MR imaging of benign uterine disease.

MR provides excellent depiction of the female pelvic anatomy and has become the imaging modality of choice for the accurate diagnosis of numerous benign gynecologic conditions. Detection and characterization of leiomyomata and adenomyosis is performed routinely at many centers, and MR plays an important role in stratifying patients into appropriate treatment options. MR imaging is also uniquely well suited to the evaluation of gynecologic conditions that occur during pregnancy and in the postpartum period. This article describes MR protocols and the typical findings of various benign conditions of the uterine corpus and cervix, including congenital anomalies, leiomyomas, adenomyosis, and complications related to pregnancy.

MR imaging of malignant uterine disease.

The role of MR imaging in the diagnosis and management of patients who have uterine malignancy continues to evolve. MR imaging has been shown to be effective for preoperative characterization and staging of endometrial and cervical carcinoma, and for the evaluation of posttreatment changes and recurrent disease. Because of its potential to provide detailed information about local extent and metastatic disease, MR imaging has enormous potential to help triage patients to appropriate treatment groups and provide imaging surveillance after therapy. This article reviews the MR imaging technique and the imaging characteristics of malignant disease of the uterine corpus and cervix.

MR imaging evaluation of the adnexa.

MR imaging has become an important tool in the evaluation of patients with adnexal disease, and its role continues to evolve. Some benign entities can be diagnosed by MR imaging with a high grade of confidence, such as teratomas, endometriomas, simple and hemorrhagic cysts, fibromas, and hydrosalpinx. In cases of malignant lesions, MR imaging may be more accurate than other modalities for lesion characterization, staging, and follow-up.

MRI of the female pelvis using vaginal gel.

OBJECTIVE: Vaginal distention with aqueous gel optimizes MRI evaluation of the vaginal walls and outer contours of the cervix. The objective of this pictorial essay is to illustrate the use of vaginal gel for MRI of the female pelvis. CONCLUSION: Distention of the vagina with gel is an inexpensive, well-tolerated procedure that may improve MRI evaluation of a variety of gynecologic conditions.

Magnetic resonance evaluation of pregnant patients with acute abdominal pain.

Acute abdominal pain in a pregnant patient is associated with a long differential diagnosis, and diagnostic imaging is often required to guide management. Ultrasound is safe and widely available; however, maternal structures may be difficult to evaluate during pregnancy due to anatomic changes. Computed tomography is accurate but exposes the fetus to ionizing radiation. Magnetic resonance (MR) imaging provides excellent anatomic resolution and tissue characterization without ionizing radiation, and MR diagnosis frequently requires no contrast administration. Using an appropriate combination of sequences, MR imaging can reliably demonstrate many causes of acute abdominal pain during pregnancy.

Female pelvis.

MR is the diagnostic imaging modality of choice for many disorders of the female pelvis. Benign uterine disease is well-demonstrated using rapid sequences and minimal examination time,whereas evaluation of malignancy is best performed with high-resolution techniques. Wide-spread availability of ultrafast sequences has expanded MR imaging applications to include evaluation of pelvic floor relaxation and fetal anomalies. Promising developments, such as new contrast agents, MR-guided focused ultrasound,and 3 tesla imaging, suggest continued advancement of MR imaging in the care of patients who have gynecologic disease.

Hypotensive patients with blunt abdominal trauma: performance of screening US.

PURPOSE: To determine retrospectively the accuracy of screening ultrasonography (US) in patients with hypotension (systolic blood pressure or =2) (consensus by three readers) and were assigned to a low- or high-risk group according to the presence of hematuria and/or axial fracture on radiographs. Screening US results were compared with findings with the best available reference standard (computed tomography [CT]), repeat US, other diagnostic test, laparotomy, autopsy, clinical course). Data were compared by using chi(2) or Fisher exact test, depending on expected frequencies, with Bonferroni correction for multiple comparisons. Continuous variables were compared by using unpaired Student t test or Mann-Whitney U test, depending on data distribution. RESULTS: The study included 77 male and 51 female patients (mean age, 42 years). Sensitivity was 85% (44 of 52) for detection of any injuries, 97% (30 of 31) for surgical injuries (ie, injuries requiring surgery), and 100% (10 of 10) for fatal injuries. Specificity was 96% (73 of 76), 82% (80 of 97), and 69% (81 of 118), and accuracy was 91% (117 of 128), 86% (110 of 128), and 71% (91 of 128), for respective injury categories. One nonfatal surgical injury was missed in a high-risk patient. For each injury category, frequency of injury in patients with a fluid score of 2 or more was nine times that in patients with a score of 0 (P < .001 for all comparisons). Frequency of false-negative US findings in high-risk patients was eight times that in low-risk patients (P < .01). CONCLUSION: In patients who are hypotensive after blunt abdominal trauma and not hemodynamically stable enough to undergo diagnostic CT, negative US findings virtually exclude surgical injury, while positive US findings indicate surgical injury in 64% of cases.

MRI of acute abdominal and pelvic pain in pregnant patients.

OBJECTIVE: The purpose of this study was to show the usefulness of MRI in the evaluation of pregnant women with acute abdominal or pelvic pain. SUBJECTS AND METHODS: All MRI studies of pregnant patients who were referred for examination because of acute abdominal or pelvic pain between June 2002 and May 2004 were included in this study (n=29). The use of MRI was at the discretion of the clinician. Fetal sonography was performed in all patients before any other imaging. A complete abdominal sonographic examination was performed in six patients before MRI. In the remaining 23 patients, MRI was the choice for primary imaging. Multiplanar multisequence MR images of the abdomen and pelvis were obtained in each patient. Unenhanced images were reviewed by an experienced radiologist to determine whether a diagnosis could be made without the administration of gadolinium. In 22 of 29 studies, gadolinium was not administered. The prospective clinical MR interpretations were compared with follow-up medical, surgical, and obstetric records to determine the correctness of the interpretation. All patients were followed up until the date of article submission or until the date of final chart entry. RESULTS: Correlation of prospective clinical MR interpretations with follow-up medical records showed correct identification of disease entities in all but one patient. In one patient, torsion of the ovary was neither described prospectively nor seen in retrospect. The following disease processes were correctly identified using MRI: appendiceal abscess (n=1), appendicitis (n=2), intraabdominal and rectus muscle abscess (n=1), intussusception (n=1), pancreatitis (n=1), ulcerative colitis (n=1), Crohn's disease with diffuse peritoneal inflammation (n=1), bilateral adrenal hemorrhage (n=1), pyelonephritis (n=2), hydronephrosis (n=1), uterine fibroid degeneration (n=2), degeneration and torsion of a submucosal uterine fibroid (n=1), simple ovarian cysts (n=1), and ovarian torsion (n=1). Twelve of the 29 patients had normal findings on MR examinations and unremarkable follow-up. CONCLUSION: The intrinsic safety of MRI and its ability to accurately show abdominal and pelvic disease in pregnant patients make it highly useful in the evaluation of these patients.

Screening sonography in pregnant patients with blunt abdominal trauma.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of screening sonography for the detection of clinically significant abdominal injury in pregnant patients with blunt trauma. METHODS: We retrospectively reviewed the records of 5173 patients with blunt abdominal trauma who underwent screening sonography. Pregnant patients were identified, and the prospective sonographic interpretations were compared with surgical findings, computed tomography (CT), subsequent sonography, cystography, and the clinical course. RESULTS: Of 1567 female patients with trauma, 947 were of reproductive age and, 102 (11%) of these 947 were pregnant. One patient was excluded because a truth standard was not available. Five (5%) of these 101 patients were found to have injuries at surgery. These injuries involved the placenta (2 injuries), spleen (2 injuries), liver (1 injury), and kidney (1 injury); all required surgery. Initial sonographic findings were positive in 4 of 5 patients with injuries. The missed injury was a placental injury detected 15 hours after screening sonography because of fetal bradycardia. After screening sonography, 6 patients underwent additional abdominal imaging: CT (3 patients), cystography (1 patient), and additional sonography (2 patients). Of 101 patients, 95 (94%) required no additional tests, and 97 (96%) required no test involving ionizing radiation. No pregnant patient underwent diagnostic peritoneal lavage. Sensitivity was 80% (95% confidence interval, 28%-100%), and specificity was 100% (96 of 96; 95% confidence interval, 96%-100%) for detecting major abdominal injury. CONCLUSIONS: Sonography is an effective screening examination that can obviate more hazardous tests such as CT, cystography, and peritoneal lavage in most pregnant patients with trauma requiring objective evaluation of the abdomen.

Cisterna chyli at routine abdominal MR imaging: a normal anatomic structure in the retrocrural space.

The cisterna chyli, a dilated lymphatic sac in the retrocrural space, represents the origin of the thoracic duct. It is seen in approximately half of lymphangiographic studies and 20% of autopsies. Highly fluid-sensitive magnetic resonance (MR) imaging sequences such as single-shot rapid acquisition with refocused echoes, which are currently used in many abdominal MR imaging protocols, frequently result in the depiction of this structure. The cisterna chyli was evident on abdominal MR images acquired in 30 (15%) of 200 consecutive patients who underwent MR imaging at the authors' institution between February and June 2002. Its appearance varied from that of a thick tube to that of a thin tube, parallel or converging tubes, tortuous tubes, a sausage-shaped fluid collection, a focal collection, or a focal plexus. Radiologists who perform MR imaging should be familiar with the various possible appearances of this normal anatomic structure so as not to mistake it for a pathologic entity.

Blunt abdominal trauma: clinical value of negative screening US scans.

PURPOSE: To assess clinical and surgical outcomes in patients with blunt abdominal trauma and negative screening ultrasonographic (US) scans. MATERIALS AND METHODS: From a database of 4,000 patients who underwent screening US for suspected blunt abdominal trauma at a level 1 trauma center, the authors retrospectively identified 3,679 patients with negative US findings. In these patients, outcome was determined by means of retrospective review of the trauma registry and all radiologic, surgical, and autopsy reports. In patients with false-negative findings at screening US, all imaging studies and medical charts were also reviewed. Proportions were statistically compared by means of the Pearson chi(2) and Fisher exact tests. Monte Carlo estimation was applied when expected frequencies were low. RESULTS: Among the 3,679 patients with negative findings at screening US, 99.9% (n = 3,641) had no injuries (true-negative findings). Differences in true-negative rates as a function of year (P >.5) or time of day (P >.3) were not significant. Among the 3,641 patients with true-negative findings, 93.6% (n = 3,407) required no additional tests and 6.4% (n = 234) underwent computed tomography or other tests. The percentage of patients who underwent additional tests was significantly higher in the 1st year of the study (19.2%) than in subsequent years (all comparisons, P <.001). Thirty-eight patients had false-negative US findings for abdominal injury. The injuries that were missed in 24 patients were nonsurgical (those that were treated successfully without intervention or were considered minor at autopsy) and those in 14 patients were surgical (required surgical intervention). Cumulatively, 65 injuries were missed. The six most common injuries included retroperitoneal hematoma (n = 13) and injuries in the spleen (n = 10), liver (n = 9), kidney (n = 8), adrenal gland (n = 8), and small bowel (n = 7). Twenty-five of the 38 patients had no or trace hemoperitoneum. Mean diagnostic delay until recognition of missed injury was 16.8 hours +/- 4.3 (standard error of the mean). The missed injury was identified within 12 hours in 19 of the 38 patients and within 24 hours in 34. CONCLUSION: The combination of negative US findings and negative clinical observation virtually excludes abdominal injury in patients who are admitted and observed for at least 12-24 hours.

Screening US for blunt abdominal trauma: objective predictors of false-negative findings and missed injuries.

PURPOSE: To determine the risk for missed injury in patients with blunt abdominal trauma and negative findings at screening ultrasonography (US) and with coexistent hematuria or fracture of the sixth through 12th ribs, lumbar spine, or pelvis. MATERIALS AND METHODS: From a database of 4,000 patients screened with US for blunt abdominal trauma at a level 1 trauma center, the 3,679 patients with negative US findings were retrospectively classified by consensus of two authors into high-risk (n = 494) and low-risk (n = 3,185) groups based on the presence of hypothetical predictors of missed injury: hematuria (n = 96) or fracture of the sixth through 12th ribs (n = 216), lumbar spine (n = 105), or pelvis (n = 174). Outcome in each patient was determined by the same two authors consensually after retrospective review of the trauma registry and all radiologic, surgical, and autopsy reports. The risk for missed abdominal injury was determined for each patient risk group and for each hypothetical predictor. Risks were statistically compared by using the Pearson chi2, Fisher exact, or Fisher-Freeman-Halton exact test, depending on expected frequencies. RESULTS: High-risk patients were 24 times more likely to have abdominal injuries after negative US findings (30 [6.1%] of 494) than were low-risk patients (eight [0.25%] of 3,185) (P <.001). Among high-risk patients, the absolute risks for missed abdominal injury associated with specific predictors were 15.6% (15 of 96 patients) for hematuria, 6.0% (13 of 216) for lower rib fractures, 7.6% (eight of 105) for lumbar spine fractures, and 5.2% (nine of 174) for pelvic fractures. Each of these risks was significantly higher for patients in the high-risk group than for those in the low-risk group (P <.001). CONCLUSION: Hematuria and fracture of the lower ribs, lumbar spine, or pelvis are objective predictors of missed abdominal injury in patients with blunt abdominal trauma and negative US findings, and such patients may benefit from additional screening with computed tomography.