Importance of communication of CT indication for imaging yield in patients with gastrointestinal bleed.

PURPOSE: The indications for requesting a diagnostic test are important for the selection and timing of imaging protocols. We sought to evaluate the diagnostic yield and impact on patient disposition when evaluating computed tomography (CT) of the abdomen and pelvis in adult patients presenting with gastrointestinal bleeding (GIB) to the Emergency Department (ED). METHODS: This study was an observational cohort study of consecutive adult ED patients with ICD10 codes related to GIB between 5/5/2018 and 6/1/2020. CT reports were reviewed for indications, exam type and findings. Reports were classified as positive (active bleeding, recent bleeding or suspected etiology for GIB), negative or other significant findings. Methodological guidelines for reporting observational studies were followed (STROBE). RESULTS: Among 943 patients with GIB during the study period, 33% (n = 312) had an abdominopelvic CT ordered. Most CTs included contrast, 64.1% (n = 200) used a single portal venous phase and 28.9% (n = 90) were multi-phase. CT identified active bleeding in 4.2% (n = 13/312) and intraluminal blood in 2.9% (n = 9/312) patients. Patients that had GIB indications on the CT order (n = 142) were more likely to receive a multiphase study compared to those without GIB indication (n = 94) (43.0% vs. 8.5%, difference 34.5%, 95% CI 23.7% to 43.7%, p < 0.0001). Patients that received multiphase studies were more likely to have a source of GIB identified compared to single-phase (18.9% vs 1.5%, OR 15.3, 95% CI 4.4 to 53.7, p < 0.0001). In 40.3% (n = 117/290) of patients without bleeding, an intra-abdominal cause for their symptoms was identified. Those with GIB or with an identified cause were more likely to be admitted. CONCLUSIONS: One-third of patients evaluated in the ED with GIB had a CT ordered. Active GIB was detected more often when multiphase exams were performed. Multiphase exams are done more often if GIB is listed in the CT indication. When a CT is positive, patients are more likely to be admitted or observed. Accurate indications are critical to optimize exam performance.

Magnetic resonance enterography is feasible and reliable in multicenter clinical trials in patients with Crohn's disease, and may help select subjects with active inflammation.

BACKGROUND: Reliable tools for patient selection are critical for clinical drug trials. AIM: To evaluate a consensus-based, standardised magnetic resonance enterography (MRE) protocol for selecting patients for inclusion in Crohn's disease (CD) multicenter clinical trials. METHODS: This study recruited 20 patients [Crohn's Disease Activity Index (CDAI) scores: <150 (n = 8); 150-220 (n = 4); 220-450 (n = 8)], to undergo ileocolonoscopy and two MREs (with and without colonic contrast) within a 14-day period. Procedures were scored centrally using, Magnetic Resonance Index of Activity (MaRIA), and both Crohn's Disease Endoscopic Index of Severity (CDEIS) and Simplified Endoscopic Score (SES-CD). RESULTS: 37 MREs were acquired. Both MREs were evaluable in 16 patients for calculation of test-retest and inter-reader reliability scores. The MaRIA scores for the terminal ileum had excellent test-retest and inter-reader reliability, with correlations >0.9. The proximal ileum showed strong within-reader agreement (0.90-0.96), and fair between-reader agreement (0.59-0.72). MRE procedures were tolerable. MaRIA scores correlated with CDEIS and SES-CD (0.63 and 0.71), but not with CDAI (0.34). MRE identified 3 patients with intra-abdominal complications, who would otherwise have been included in clinical trials. Furthermore, both MRE and ileocolonoscopy identified active bowel wall inflammation in 2 patients with CDAI <150, and none in 1 patient with CDAI > 220. Data quality was good/excellent in 85% of scans, and fair or better in 96%. CONCLUSIONS: Magnetic resonance enterography of high-quality and reproducibility was feasible in a global multi- centre setting, with evidence for improved selectivity over CDAI and ileocolonoscopy in identifying appropriate CD patients for inclusion in therapeutic intervention trials.

Liver stiffness measurement by magnetic resonance elastography is not associated with developing hepatocellular carcinoma in subjects with compensated cirrhosis.

BACKGROUND: Liver stiffness assessed using transient elastography is described as a potential risk factor for hepatocellular carcinoma (HCC) in cirrhosis. However, the strict assessment of hepatic parenchymal areas uninvolved with HCC has not been investigated. AIM: To determine if liver stiffness of nonmalignant hepatic parenchyma using magnetic resonance elastography (MRE) is higher in patients with HCC compared with controls. METHODS: Cases were defined by compensated cirrhosis with a Child-Turcotte-Pugh score <7 and HCC by radiological criteria or histology. Control subjects with compensated cirrhosis were frequency matched with cases by gender and disease aetiology. Overt manifestations of portal hypertension and previous therapy for liver disease or HCC were exclusion criteria. Region of interest analyses were performed on hepatic parenchyma regions distant to HCC location among cases. RESULTS: Thirty patients with HCC and 60 matched controls comprised the study cohort. The mean age for cases was 64±10 years (range, 45-85) with 70% being men. Major disease aetiologies were chronic viral hepatitis (57%), non-alcoholic fatty liver disease (33%) and alcohol (10%). Twenty-eight (93%) patients had solitary HCC lesions with a mean size of 5.2 cm (range, 2-14 cm). However, patients with HCC had similar liver stiffness among uninvolved areas distant to HCC lesions, when compared with controls without HCC (mean, 6.1±2.0 vs. 6.3±2.5 kPa, P=0.7). CONCLUSION: In contrast to previous studies with transient elastography, we did not observe a systematic association between liver stiffness assessed using MRE and the presence of HCC in patients with compensated cirrhosis.

CT enterography and fistulizing Crohn's disease: clinical benefit and radiographic findings.

BACKGROUND: To estimate the clinical benefit of CT enterography (CTE) in patients with fistulizing Crohn's disease and describe the appearance of fistulas at CTE. METHODS: Crohn's patients who had undergone CTE, which diagnosed an abscess or fistula, were identified. A gastroenterologist reviewed clinical notes prior to and following CTE to assess the pre-CTE clinical suspicion for fistula/abscess, and post-CTE alteration in patient management. A radiologist reassessed all fistula-positive cases, which were confirmed by a non-CT reference standard, to describe their radiologic appearance. RESULTS: Fifty-six patients had CT exams identifying 19 abscesses and 56 fistulas. There was no or remote suspicion of fistula or abscess at pre-imaging clinical assessment in 50% of patients. Thirty-four patients (61%) required a change in or initiation of medical therapy and another 10 (18%) underwent an interventional procedure based on CT enterography findings. Among 37 fistulas with reference standard confirmation, 30 (81%) were extraenteric tracts, and 32 (86%) were hyperenhancing compared to adjacent bowel loops. Most fistulas (68%) contained no internal air or fluid. CONCLUSION: CTE detects clinically occult fistulas and abscesses, resulting in changes in medical management and radiologic or surgical intervention. Most fistulas appear as hyperenhancing, extraenteric tracts, usually without internal air or fluid.

Preoperative detection of pancreatic insulinomas on multiphasic helical CT.

OBJECTIVE: The objective was to analyze enhancement characteristics of insulinomas and to determine the ability of multiphase CT to localize these tumors. MATERIALS AND METHODS: Prospective interpretations of multiphase helical CT scans were reviewed in 30 patients who had insulinomas resected over a 5-year period. CT scans were retrospectively reviewed to determine enhancement characteristics, tumor conspicuity in each phase of enhancement, and potential causes for false-negative findings. RESULTS: Sixty-three percent (19/30) of tumors were identified on CT prospectively. An additional six tumors were visualized in retrospect, allowing characterization of 25 (83%) of 30 tumors. Most tumors were hyperdense on at least one phase (n = 19), three tumors were hypoattenuating, and three were isodense and pedunculated. Insulinomas were most conspicuous on the early phase in 15 patients and in the portal venous phase in three. All tumors that underwent pancreatic phase imaging were seen (13/13), whereas three of 18 arterial and six of 25 portal venous phase findings were inconclusive for tumor. In the six examinations with false-negative findings in which the tumor could be seen in retrospect, two tumors were isodense and pedunculated, three were in close proximity to vessels, and one had a cystic appearance. CONCLUSION: Multiphasic CT has a moderate sensitivity in the detection of insulinomas. Most tumors are more conspicuous on the earlier phases of enhancement. The pancreatic phase may be more useful than the arterial phase. Potential sources of false-negative results include tumors adjacent to vessels, pedunculated morphology, or nonhyperattenuating lesions.

Detection of flat lesions in the colon with CT colonography.

BACKGROUND: We investigated whether flat lesions of the colon could be detected on computed tomographic colonography (CTC). METHODS: CTC and conventional colonoscopy were performed on 547 consecutive patients. A subset of 22 polyps was described as flat on colonoscopy (n = 16) or CTC (n = 6) and are the basis of this report. CTC was performed with a standard technique (5-mm collimation, 3-mm reconstruction intervals). Patients were scanned in supine and prone positions. Examinations were randomly assigned and reviewed in a blinded fashion by two of three radiologists. Prospective interpretations were recorded. All patients had conventional colonoscopy, which served as the gold standard. RESULTS: Twenty-two flat lesions ranging from 0.4 to 3.5 cm were histologically classified as adenomatous (n = 8) or hyperplastic (n = 14). The sensitivities for detecting all flat lesions and flat adenomas by each reviewer were 43% and 100%, 65% and 100%, and 15% and 13%, respectively. "Double reading" resulted in detection of 68% of all lesions and 100% of adenomas. Of the seven hyperplastic polyps missed by both reviewers, four were identified retrospectively. CONCLUSION: Flat lesions of the colon represent an important source of false negative CTC examinations. Awareness of their morphology can assist radiologists in finding most of these challenging lesions.

Imaging of neuroendocrine tumors of the pancreas.

BACKGROUND: Neuroendocrine tumors of the pancreas are uncommon neoplasms of the pancreas that can occur sporadically or in association with various syndromes such as multiple endocrine neoplasia type 1 (MEN I). Patients can present with a specific clinical syndrome related to biochemically functioning tumors or with nonspecific symptoms related to mass effect or metastases. The size, function, consistency, and malignant behavior of neuroendocrine tumors are integrally related. Imaging has a major role in the preoperative localization of the primary tumor and detection of metastases. Several techniques are available including ultrasound, endoscopic ultrasound, computed tomography (CT), MR, somatostatin receptor scintigraphy, angiography, and arterial stimulation with venous sampling; each with unique advantages and limitations. The reported performance for these techniques vary widely, and as a result, recommended imaging algorithms are controversial. Recent technical advances in ultrasound, CT, and MRI have occurred that may improve the sensitivity of some of the techniques. Further improvements are likely in the future. In this chapter we will review imaging techniques used to study the pancreas as it relates to the detection of neuroendocrine tumors, imaging findings of these tumors using various imaging modalities, and the advantages, limitations and results obtained with each technique.

Aortic prosthetic graft infections: radiologic manifestations and implications for management.

Prosthetic graft infections are an uncommon complication of aortic bypass. These infections may have serious sequelae such as limb loss and can be lethal. They are hard to eradicate and, under certain circumstances, difficult to diagnose. Usually, computed tomography (CT) is the most efficacious imaging method for diagnosis of graft infections due to its quick availability. The sensitivity of magnetic resonance imaging in detection of perigraft infection has not been thoroughly investigated but is probably similar to that of CT. After the early postoperative period, persistent or expanding perigraft soft tissue, fluid, and gas are the CT findings of graft infection. Aortoenteric fistula should be considered a subset of aortic graft infection; however, perigraft air is more likely to be seen with an aortoenteric fistula. Other conditions associated with graft infection include pseudoaneurysm, hydronephrosis, and osteomyelitis. Adjunctive studies such as sinography, ultrasonography, gallium scanning, and labeled white blood cell scanning can be quite useful in diagnosis, determination of the extent of disease, and selection of the treatment modality. White blood cell scanning is an important complementary test to CT in ambiguous cases, such as in the early postoperative period, and may be more sensitive in detection of early graft infection.

CT angiography of complications in pediatric patients treated with intravascular stents.

OBJECTIVE: Our goal was to determine whether CT angiography can reveal complications in pediatric patients and young adults treated with intravascular stents for obstructive vascular lesions. CONCLUSION: CT angiography can reveal complications in pediatric patients treated with intravascular stents for obstructive lesions. Potentially, CT angiography could replace the more invasive conventional angiography currently used for intravascular stent placement and follow-up examinations.

Small-bowel motility disturbances: a comparison of small-bowel series and antroduodenal manometry.

RATIONALE AND OBJECTIVES: The authors' purpose was to compare the findings of small-bowel series with those of antroduodenal manometry to determine whether normal findings from a small-bowel series would make it unnecessary to perform antroduodenal manometry. MATERIALS AND METHODS: The findings from 33 small-bowel series performed on patients who had undergone antroduodenal manometry were retrospectively reviewed for abnormalities, including dilatation, transit time, fold thickening, and increased fluid. Antroduodenal manometry findings were classified into the following categories: normal, myopathy, neuropathy, obstructions, or nonspecific conditions. RESULTS: Nine of 12 patients with specific abnormalities at antroduodenal manometry had abnormal results from the small-bowel series. Of seven patients with normal small-bowel series results, three had abnormal antroduodenal manometry results--two had previously undergone vagotomy with neuropathic changes and one had myopathic changes. CONCLUSION: Small-bowel series and antroduodenal manometry are complementary examinations. Only a small number of patients with normal small-bowel series results will have abnormal results at antroduodenal manometry. A large number of patients with motility abnormalities have a combination of nonspecific changes, such as dilatation and increased fluid, at a small-bowel series.

Demonstration of intraluminal duodenal diverticulum by computed tomography.

Intraluminal duodenal diverticulum is a rare congenital anomaly consisting of a saclike projection within the duodenum. Small diverticula may be asymptomatic; however, when these enlarge, patients may develop recurrent episodes of pain, obstruction, or pancreatitis. Normally, the diagnosis is made by barium luminal examination. We report a case where the findings were seen on computed tomography and confirmed by upper gastrointestinal series.

Fast spoiled gradient-recalled MR imaging of thoracic aortic dissection: preliminary clinical experience at 1.5 T.

The purpose of this study was to evaluate fast spoiled gradient-recalled (FSPGR) magnetic resonance (MR) imaging in the diagnosis of thoracic aortic dissection (TAD). Twenty-eight patients with suspected TAD underwent MR imaging with FSPGR and either cine or cardiac-gated spin-echo MR techniques. The average scanning time for the FSPGR images was approximately 1 min. Three readers interpreted the FSPGR images for the presence or absence of TAD. An ROC analysis was done. At a specificity of 90%, the sensitivity ranged from 52% to 90% for the three readers. Pulsatility artifacts and mural thrombus were causes of false-positive and false-negative readings. The areas under the ROC curves (Az) ranged from 0.85 to 0.97 for the three readers. There was a statistically significant difference in the Az values for two of the experienced readers (p = .02). The correct type of dissection was determined in only 65% of the true-positive diagnoses. FSPGR has a very limited role in screening and for rapid evaluation of the unstable patient. The results are reader dependent and susceptible to pulsatility artifacts. Determination of the type of dissection is limited. With a suspected thoracic aortic dissection, therefore, additional imaging sequences should be obtained to maximize accuracy.

Cardiopulmonary complications of pregnancy: radiographic findings.

Physiologic changes during pregnancy affect nearly every organ system. In the thorax, the diaphragm elevates as much as 4 cm because of displacement of the abdominal organs by the gravid uterus, resulting in lower lung volumes. Maternal blood volume and cardiac output increase approximately 45% by mid-pregnancy. Cardiac output can increase as much as 80% during vaginal delivery and up to 50% with cesarean section. These changes result in pulmonary vascular engorgement, progressive left ventricular dilatation, and mild hypertrophy (Fig. 1). Pregnant patients are also prone to a number of pulmonary insults, including infection, aspiration, and neoplastic disease. These abnormalities have several radiographic patterns: cardiogenic and noncardiogenic pulmonary edema, focal pulmonary abnormalities, and extraalveolar air. Radiologists must recognize not only the normal chest radiographic appearance in these patients but also the thoracic complications associated with pregnancy.