Michael P. Federle

Computed tomography in the diagnosis of blunt intestinal and mesenteric injuries.

Twenty-four patients with signs on computed tomography (CT) of mesenteric or intestinal injury were treated over a 5-year period (1980-1984). All patients were the victims of blunt abdominal trauma. Nine patients with CT evidence of mesenteric or bowel hematomas were observed without adverse outcome. Fifteen were operatively explored, with 14 having injuries similar to the findings on the preoperative CT scans. In the group that had surgery, either thickened bowel or free intraperitoneal fluid (blood or less dense fluid) or both were present in all but one patient. Extraluminal air (three cases) or Gastrografin (Squibb) (one case) were absolute indications for surgery, as were bowel wall or mesenteric hematomas accompanied by substantial amounts of intraperitoneal fluid. The patients history, physical examination, and initial laboratory values are important in proper selection of patients for CT evaluation. We feel that CT appears to offer certain definite advantages over peritoneal lavage in evaluation of bowel and mesenteric injuries and can reliably help to distinguish the injuries that require surgical repair from those that can be safely monitored and observed.

Computerized tomographic staging of renal trauma: 85 consecutive cases.

In 85 patients with renal trauma we compared the findings on computerized tomography with those of excretory urography, renal surgery, intra-abdominal surgery and angiography. Patients underwent computerized tomography because of a suspected associated thoracic or abdominal injury, or indeterminate findings on excretory urography, nephrotomography or angiography. Blunt trauma accounted for 87.1 per cent of the renal injuries and penetrating trauma for 12.9 per cent. The most common findings on computerized tomography were perirenal hematoma in 29.4 per cent, intrarenal hematoma in 24.7 per cent and parenchymal disruption in 17.6 per cent. In 33 patients who underwent laparotomy computerized tomographic staging was confirmed. In contrast, the most common finding on excretory urography, diminished opacification (17 of 53 patients), was found to have no correlation with the severity of renal injury as assessed by computerized tomography or laparotomy. Angiography appreciably understaged 1 of 5 cases by failing to show extracapsular extravasation with parenchymal disruption. All findings on angiography were depicted by computerized tomography. We conclude that computerized tomographic staging for renal trauma is more sensitive and specific than excretory urography, nephrotomography and angiography, and that it should be used primarily when multiple traumatic injuries are suspected, when excretory urography suggests major trauma or is nonspecific and when clinical evidence of major trauma exists, regardless of what excretory urography shows.

Peliosis Hepatis: Spectrum of Imaging Findings

OBJECTIVE It is important to recognize the imaging characteristics of peliosis hepatis because peliotic lesions may mimic several different types of focal hepatic lesions CONCLUSION We illustrate the spectrum of imaging findings of peliosis hepatis, including sonography, CT, MR, and angiography.

In vivo three-dimensional surface geometry of abdominal aortic aneurysms.

AbstractAbdominal aortic aneurysm (AAA) is a local, progressive dilation of the distal aorta that risks rupture until treated. Using the law of Laplace, in vivo assessment of AAA surface geometry could identify regions of high wall tensions as well as provide critical dimensional and shape data for customized endoluminal stent grafts. In this study, six patients with AAA underwent spiral computed tomography imaging and the inner wall of each AAA was identified, digitized, and reconstructed. A biquadric surface patch technique was used to compute the local principal curvatures, which required no assumptions regarding axisymmetry or other shape characteristics of the AAA surface. The spatial distribution of AAA principal curvatures demonstrated substantial axial asymmetry, and included adjacent elliptical and hyperbolic regions. To determine how much the curvature spatial distributions were dependent on tortuosity versus bulging, the effects of AAA tortuosity were removed from the three-dimensional (3D) reconstructions by aligning the centroids of each digitized contour to the z axis. The spatial distribution of principal curvatures of the modified 3D reconstructions were found to be largely axisymmetric, suggesting that much of the surface geometric asymmetry is due to AAA bending. On average, AAA surface area increased by 56% and abdominal aortic length increased by 27% over those for the normal aorta. Our results indicate that AAA surface geometry is highly complex and cannot be simulated by simple axisymmetric models, and suggests an equally complex wall stress distribution.

Internal hernia: an increasingly common cause of small bowel obstruction.

Internal hernia is an uncommon cause of small bowel obstruction that may be increasing in frequency. Because the clinical diagnosis of internal hernia is difficult, imaging studies such as computed tomography (CT) and small bowel follow through play an important role. Transmesenteric hernia is the most common type and is usually related to prior abdominal surgery, especially with creation of a Roux-en-Y anastomosis (eg, liver transplantation, gastric bypass). CT may allow confident diagnosis in most cases. In this article, we review the clinical and imaging findings of internal hernia based on our experience with 54 cases of surgically proven internal hernias including 45 transmesenteric, 6 paraduodenal, and 3 omental hernias, 39 of which had imaging studies available for review.

Evaluation of Renal Injuries with Computerized Tomography

To document the severity and degree of renal injury multiple studies may be necessary, including excretory urography, nephrotomography and arteriography. Even these extensive studies fail at times to provide sufficient information for treatment of the injury. The need for a more accurate noninvasive modality led us to investigate the use of computerized tomography. We used computerized tomography and excretory urography, and/or nephrotomography in 24 patients suspected of having major renal injury. Computerized tomography clearly separated minor injuries (superficial laceration) from major injuries (deep lacerations or laceration with extravasation). Computerized tomography demonstrated extravasation of opacified urine not noted on excretory urography in 5 cases. In all cases renal lacerations, and perirenal and intrarenal hematomas were defined clearly on computerized tomography. Computerized tomography provided information for proper management in all instances (18 nonsurgical and 6 surgical procedures) and all computerized tomography findings were confirmed at operation. Concomitantly, computerized tomography detected liver, spleen or pancreas injuries in 4 patients. Computerized tomography provides a highly sensitive and accurate method to evaluate renal trauma, which allows the surgeon to make a confident choice of treatment.

Management of blunt splenic trauma: significant differences between adults and children.

BACKGROUND Although highly successful in children, nonoperative management of blunt splenic injury in adults is less defined. The purpose of this study was to determine whether mechanism of injury, grade of splenic injury, associated injuries, and pattern of injury differ between adults and children (younger than 15 years of age). METHODS Four hundred eleven patients (293 adults and 118 pediatric patients) with blunt splenic injury were admitted to an affiliated adult/pediatric trauma program from 1989 to 1994. Computed tomography (CT) scans were interpreted in a blinded fashion. Mechanism of injury was significantly different for adults versus children (p < 0.05): motor vehicle crash (66.9% versus 23.7%), motorcycle (8.8% versus 0.8%), sports (2.4% versus 16.9%), falls (8.8% versus 25.4%), pedestrian/automobile (4.4% versus 11.0%), bicycle (1.4% versus 9.3%), and other (7.3% versus 12.7%). RESULTS Higher injury severity scores, lower Glasgow Coma Scales, and higher mortality indicated that the adults were more severely injured than the children. Fifty-nine percent of the adults and 7% of the children required immediate laparotomy for splenic injury. Both CT grade and quantity of blood on CT predicted the need for exploration in adults but not in children. An injury severity score above 15 and high-energy mechanisms correlated with the need for operative intervention. CONCLUSIONS Rather than children simply being physically different, they are injured differently than adults, hence the high rate of nonoperative management.

CT of Nonneoplastic Hepatic Vascular and Perfusion Disorders

The unique dual blood supply of the liver (75% portal venous, 25% hepatic arterial) makes multiphase helical computed tomography (CT) a highly suitable technique for hepatic evaluation with imaging in two (arterial and portal venous) or more phases. Multiphase helical CT has become an important tool in the detection and characterization of hepatic tumors. In some situations, hemodynamic changes might mimic neoplastic or inflammatory lesions and evoke diagnostic uncertainty. To confidently identify hepatic conditions such as venous outflow obstruction (Budd-Chiari syndrome), arterioportal shunts, hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome), peliosis hepatis, passive congestion, and hepatic infarction, radiologists must be familiar with the disease-specific CT appearances and related clinical manifestations.

Noninvasive quantitation of liver iron in dogs with hemochromatosis using dual-energy CT scanning.

The concentration of iron deposited in the livers of two dogs with experimentally induced iron overload was determined by use of dual energy computerized tomographic (CT) scanning. A phantom was constructed, containing known amounts of iron-dextran solutions. CT scans of the phantoms, at 80 and 120 kVp, corrected for the response of water, showed a linear relationship between known iron concentrations and difference in CT number at the two scanning energies, with a change of 24 H units per 1000 mg% iron. Using the graph of this linear relationship, the amount of iron in dog liver was predicted, compared with the amount of iron measured from biopsy specimens, and analyzed by neutron activation analysis. A close correlation existed between predicted liver iron and measured iron concentration (r = 0.99). Dual-energy CT scanning appears to provide an accurate, noninvasive method of quantitating liver iron.

Budd-Chiari syndrome: Imaging with pathologic correlation

We retrospectively evaluated 21 patients with Budd-Chiari syndrome who underwent liver transplant. The pathological findings were correlated with imaging studies that included computed tomography (CT) in all cases, sonography in 20, and magnetic resonance (MR) in 15. Pathological features of Budd-Chiari syndrome in subacute or chronic form, such as parenchymal fibrosis, hemorrhage, and congestion, were found in all resected livers. These occurred usually in conjunction with restricted hepatic veins due to thrombosis or fibrosis with partially recanalized lumen. The status of hepatic veins was correctly assessed and correlated with pathology in 13 of 20 patients who had sonograms, in 12 of 15 patients who had MR, and in nine of 18 patients with contrast-enhanced CT scans. Patency of the inferior vena cava was well seen by all three modalities; parenchymal abnormalities were best visible on CT (19 of 21), while ascites, caudate lobe enlargement and collateral vessels were best detected with MR or CT. We conclude that each imaging modality offers certain values and limitations in the assessment of vascular or parenchymal findings in Budd-Chiari syndrome.