Pancreatic emergencies

Sonography and CT scan remain the examinations of choice for evaluating pancreatic diseases. This article addresses the clinical and imaging features of the two most important pancreatic emergencies: (1) pancreatitis and (2) trauma. The rationale for selecting sonography or CT scan is also addressed.

Bowel wall thickening in children: differentiation with US

PURPOSE

To determine whether vascular, ischemic, and inflammatory causes of bowel wall thickening in children can be differentiated at gray-scale and color Doppler ultrasonography (US).

MATERIALS AND METHODS

Thirty-seven children with acute bowel disease underwent graded compression US. Findings of bowel wall thickness, wall echotexture, location of bowel involvement, and presence of color Doppler flow were evaluated. Diagnoses were classified as inflammation (n = 25), vasculitis (n = 7), or ischemia (n = 5) and were confirmed with findings from colonoscopy and biopsy, stool culture analysis, surgery, and cutaneous biopsy, and with a combination of clinical and laboratory data.

RESULTS

Patient age (P = .0022), bowel wall thickness (P = .0001), and color Doppler flow (P = .0013) were statistically significantly related to disease type. Wall thickening and absence of visible color Doppler flow suggested ischemia. Older patient age and visible color Doppler flow suggested inflammation, whereas younger patient age and visible color flow suggested vasculitis. Difference in location of bowel disease in patients with ischemic versus those with vascular wall thickening was statistically significant (P = .0185). No difference was found between disease type and wall stratification.

CONCLUSION

Gray-scale and color Doppler flow US can aid in differentiating ischemic, vascular, and inflammatory bowel wall thickening.

Vascular rings in symptomatic children: frequency of chest radiographic findings

PURPOSE

To determine the relative frequency of radiographic findings in symptomatic children with vascular rings.

MATERIALS AND METHODS

Preoperative chest radiographs in 41 children (mean age, 21 months) with surgically proved vascular rings were retrospectively analyzed. There were 41 frontal and 39 lateral radiographs. Lateral views were evaluated for retrotracheal opacity, tracheal narrowing, and anterior tracheal bowing. The aortic arch, descending aorta, and tracheal indentation were assessed on frontal views.

RESULTS

Findings on 39 lateral radiographs included increased retrotracheal opacity on 31 (79%), anterior tracheal bowing on 36 (92%), and tracheal narrowing on 30 (77%) radiographs. All findings were present on 24 (62%) radiographs. Findings on 41 frontal radiographs included right aortic arch on 35 (85%), distal tracheal indentation on 30 (73%), and right descending aorta on 27 (66%) radiographs. All findings were present on 20 (49%) radiographs. Four (10%) frontal radiographs were normal or indeterminate. The combination of frontal and lateral views showed at least one abnormality in every patient. No symptomatic patient with a vascular ring had a normal radiograph.

CONCLUSION

A normal chest radiograph is evidence against the presence of a vascular ring in symptomatic children. Both lateral and frontal radiographs are important in diagnosis.

Scapulothoracic dissociation caused by blunt trauma

Scapulothoracic dissociation is an infrequent injury with a potentially devastating outcome. The diagnosis has heretofore relied on the radiographic description of the forequarter disruption. Recent experience with four patients at a single trauma center, along with review of 54 injuries adequately described in the literature, indicates a broader spectrum of injury. Neurologic injuries occurred in 94% and vascular injuries in 88%. A nearly uniform poor outcome with flail extremity in 52% of patients, early amputation in 21%, and death in 10% reflects the severity of injuries reported. Identification of this injury requires clinical suspicion, based upon the injury mechanism and physical findings, to accurately assess the degree of trauma to musculoskeletal, neurologic, and vascular structures. Based upon these clinical findings, a rational approach to diagnostic techniques, injury classification, and appropriate surgical intervention can be achieved. Outcome is dependent on early recognition of the subset of patients with injuries amenable to surgical treatment and rehabilitation.

Pediatric chest MR imaging. Noncardiac clinical uses

MR imaging in the evaluation of noncardiac chest diseases is used primarily to supplement CT examinations. Because of its high soft-tissue contrast and ability to detect flowing blood, MR imaging has significant advantages for assessing tissue characteristics and vascular pathologic conditions. This article reviews imaging techniques and the MR appearance of mediastinal vascular anomalies, mediastinal and chest wall tumors, and post-treatment changes.

Ghosting of pulmonary nodules with respiratory motion: comparison of helical and conventional CT using an in vitro pediatric model

OBJECTIVE

The study was designed to compare helical CT with varying pitch and reconstruction intervals and conventional CT for revealing pulmonary nodules in a model that simulates respiratory motion in children.

MATERIALS AND METHODS

CT scans were obtained in an experimental model with one nodule (3 or 10 mm) in each scan. One-second scans were obtained at rates of 10, 20, and 30 respirations per minute using conventional CT with 4-mm collimation and table incrementation and helical CT with 4-mm collimation and either 4-mm/sec (pitch, 1:1) or 8-mm/sec (pitch, 2:1) table speed. Reconstructions were at 1-, 2-, and 4-mm intervals for scans obtained using 4-mm/sec table speed and at 1- and 4-mm intervals for scans obtained using 8-mm/sec table speed. Images were independently reviewed by three radiologists who estimated the number of nodules on each image.

RESULTS

Ghosting (depiction of more than one nodule in a study) was seen in 79%, 80%, and 75% of helical CT scans obtained with a 1:1 pitch using 1-, 2-, and 4-mm reconstruction intervals, respectively. By comparison, ghosting was seen in only 54% and 58% of helical CT scans with a 2:1 pitch using 1-mm reconstruction intervals and 4-mm reconstruction intervals, respectively, and in 56% of conventional CT scans (p < .0001). A single nodule was detected on all other scans, and at least one nodule was seen on all scans.

CONCLUSION

Ghosting of nodules is common in this model. Ghosting was seen less often on conventional scans and helical scans with 2:1 pitch than it was on helical scans with 1:1 pitch. Nonetheless, ghosting was seen on more than 50% of all scans with each technique.

MR imaging of the liver in children

MR imaging provides an excellent morphologic depiction of the normal and abnormal liver. Although sonography remains the primary imaging technique used for detecting hepatic diseases, MR imaging is being used increasingly for characterization and staging of hepatic lesions. This article reviews the techniques of hepatic MR imaging in children and the MR appearance of neoplasms, parenchymal diseases, and vascular disorders in childhood.

Bone marrow imaging in children

By virtue of its ability to separate hematopoietic from fatty marrow, MR imaging is ideal for detecting marrow lesions. This article reviews the techniques of bone marrow imaging, interpretive pitfalls, anatomic variations with patient age, and the alterations in bone marrow signal occurring in a variety of pathologic conditions.

Techniques and strategies in pediatric body MR imaging

The tools available from MR imaging provide the pediatric radiologist great versatility in detecting and characterizing disease in children. An understanding of the strengths and limitations is essential for selecting the best technique to answer the clinical question in the shortest amount of time.