Diagnostic and interventional ultrasound of the pediatric spine.

Ultrasound is useful as a diagnostic tool in the evaluation of the pediatric spine, and can also help guide procedures in the interventional radiology suite or the operating room. This pictorial exhibit will display examples of diagnostic and interventional uses of ultrasound with respect to the pediatric spine.

Diagnostic and interventional ultrasonography in neonatal and infant lumbar puncture.

BACKGROUND: Lumbar puncture (LP) may be unsuccessful clinically, prompting image-guided LP by radiologists. Objective. To investigate the utility of ultrasound (US) in diagnosing the cause of failed LP and in guiding LP. MATERIALS AND METHODS: Neonates and infants referred for image-guided LP underwent spine US of the thecal sac. When indicated, image-guided LP was performed. RESULTS: Forty-seven evaluations and interventions were performed in 32 patients. All patients were initially evaluated after failed blind LP attempts. Twenty-three of the initial US studies showed intrathecal and/ or epidural echogenic hematoma, which obliterated the CSF space; 5 showed minimal fluid, and 4 had normal examinations. LP was deferred or cancelled in 14 cases based upon initial US findings. Image-guided LP was performed 32 times in 19 patients. US guidance was used in 26, fluoroscopy in 3, and fluoroscopy with US assistance in 3. Using US, LP was performed in 9 patients with no visible CSF: 2 samples were sufficient for culture only. Six patients had minimal CSF US: 4 provided usable CSF samples. Clear CSF space was seen in 11: all had successful LP. CONCLUSIONS: US can disclose the cause of failed LP, can help determine whether or not to intervene further, and can provide guidance for LP.

Accuracy of visual determination of neutral position of the immobilized pediatric cervical spine.

BACKGROUND: The definition of neutral position for the immobilized pediatric cervical spine is not well standardized. In this study, we attempted to determine whether 1) physicians and/or paramedics could accurately assess visually if the cervical spine was in a neutral position, 2) the visual assessments of the observers were in agreement, and 3) a radiographic Cobb angle would correlate with the visual determination. METHODS: Children presenting to a pediatric emergency department (ED) in full spinal immobilization were randomly selected (convenience sample) for this prospective study. The emergency physician and transporting paramedic independently determined positioning of the cervical spine. A radiologist, blinded to clinical information, determined Cobb angles from radiographs of the immobilized cervical spines. RESULTS: Of the 59 children studied, the evaluation of cervical spine position by the physician and paramedic correlated in 88% of the cases. For the 22 children with non-neutral Cobb angles (definition of neutral: between 5 degrees flexion and 5 degrees extension), observers agreed in 100% of the cases. However, in 21 of these cases (95%) the position was observed as neutral. CONCLUSIONS: Although visual determinations of neutral position of the cervical spine by two observers may correlate, radiographic studies demonstrate that neutral position was not achieved in 37% of the cases.

Percutaneous nephrostomy in children and adolescents: outpatient management.

PURPOSE: To determine if percutaneous nephrostomy can be performed safely as an outpatient procedure in children and adolescents. MATERIALS AND METHODS: Percutaneous nephrostomy was performed in 102 kidneys in 87 patients at 93 separate encounters. Patients were excluded from outpatient treatment if they presented with signs of infection, were hospitalized for other reasons, were undergoing additional endourologic stone procedures, had solitary kidneys or poor renal function, had social problems precluding outpatient care, or had a procedural complication. Follow-up was performed by means of direct communication and/or chart review. RESULTS: Successful outpatient percutaneous nephrostomy was performed in 39 (42%) of the 93 encounters. Reasons for exclusion included infection (n = 23), concomitant problems requiring hospitalization (n = 11), stone therapy (n = 7), solitary kidney with renal failure (n = 3), and social reasons (n = 10). No procedure-related complication occurred. No patient required readmission within 3 weeks for a tube- or procedure-related problem. CONCLUSION: Outpatient percutaneous nephrostomy can be safely performed in a selected group of patients.

Collision tumors in children: a review of the literature and presentation of a rare case of mesoblastic nephroma and neuroblastoma in an infant.

A mass made up of 2 distinct synchronous primary malignant tumors is a rare event in adults, and exceedingly so in children. Such lesions have been called collision tumors. Reported here is an infant who was found to have a collision tumor comprised of a neuroblastoma and a congenital mesoblastic nephroma, in contiguity, in the right kidney. This is the first report of a collision tumor in an infant. This also is the first report of a synchronous occurrence of a neuroblastoma and a congenital mesoblastic nephroma. The authors present this case and discuss the available literature.

Focused abdominal sonography for trauma (FAST) in children with blunt abdominal trauma.

BACKGROUND: Focused abdominal sonography for trauma (FAST) has been well reported in adults, but its applicability in children is less well established. We decided to test the hypothesis that FAST and computed tomography (CT) are equivalent imaging studies in the setting of pediatric blunt abdominal trauma. METHODS: One hundred seven hemodynamically stable children undergoing CT for blunt abdominal trauma were prospectively investigated using FAST. The ability of FAST to predict injury by detecting free intraperitoneal fluid was compared with CT as the imaging standard. RESULTS: Thirty-two patients had CT documented injuries. There were no late injuries missed by CT. FAST detected free fluid in 12 patients. Ten patients had solid organ injury but no free fluid and, thus, were not detected by FAST. The sensitivity of FAST relative to CT was only 0.55 and the negative predictive value was only 0.50. CONCLUSION: FAST has insufficient sensitivity and negative predictive value to be used as a screening imaging test in hemodynamically stable children with blunt abdominal trauma.

Recurrent deep venous thrombosis complicating PICC line placement in two patients with cystic fibrosis and activated protein C-resistance.

Two patients with cystic fibrosis and activated protein C-resistance experienced deep vein thrombosis complicating peripherally inserted central catheter (PICC) use. Cystic fibrosis patients may be at increased risk for catheter rotated thrombosis.

Intraluminal colon pressure dynamics with Valsalva maneuver during air enema study.

PURPOSE: To determine the effects of the Valsalva maneuver on intraluminal colon pressure during air enema studies. MATERIALS AND METHODS: Air enema studies were performed in four adult volunteers, and intraluminal colon pressure measurements were recorded with a high-speed electronic strip chart and aneroid gauge methods. One hundred thirty-five Valsalva maneuvers were produced with open- and closed-glottis maneuvers, with varying degrees of straining, and during normal peristalsis. RESULTS: Valsalva pressure waves are discrete waveforms that can be distinguished from baseline insufflation and normal peristaltic waves. Valsalva waves are of both simple and complex types. The range of peak Valsalva pressures was 12-148 mm Hg. Average mild, moderate, and vigorous pressures with a closed glottis were 22, 38, and 90 mm Hg, respectively. High pressures (120-130 mm Hg) were observed with open- and closed-glottis maneuvers. CONCLUSION: Valsalva maneuvers increase intracolonic pressure 12-148 mm Hg above baseline pressure. Valsalva pressure waves are discrete and can be accurately detected with both aneroid and electronic transducer systems.

From the RSNA refresher courses. Freehand interventional sonography in the breast: basic principles and clinical applications.

The skills needed to perform ultrasonographic (US)-guided interventional procedures in the breast can be learned by practicing the key maneuvers on a tissue phantom. Use of a tissue phantom rather than a synthetic phantom provides the tactile feedback from transducer movement against tissue and from needle insertion into tissue, which more closely simulates the performance of the procedure in a real breast. There are three key transducer motions--sweeping, rocking, and rotating--that are used to achieve three important goals in US-guided procedures: finding the needle, maximally visualizing the needle, and correctly aligning the needle shaft and ultrasound beam. For each transducer maneuver, there is a corollary needle motion that can be used to achieve the same goal. Either the transducer or the needle should be moved during a procedure, not both simultaneously. Longitudinal alignment of the needle shaft with the ultrasound beam is best achieved with the perpendicular approach. The perpendicular approach is preferred because it allows superior needle visualization, orientation parallel to the chest wall, and location of the needle shaft at the focal zone. With use of a tissue phantom, the radiologist-in-training can practice the key procedures and tailor them to his or her individual preferences.

John Caffey Award. Colonic perforation by air and liquid enemas: comparison study in young pigs.

OBJECTIVE: Hydrostatic enema reduction of intussusception in children has been replaced by pneumatic reduction in a number of institutions. Colonic perforation occurs in as many as 2.8% of enema reductions, and questions persist about the relative safety of enemas performed with air vs fluid. The objectives of this study were to investigate and compare the pathologic patterns of in vivo colonic perforation and fecal spillage in young pigs given air and hydrostatic enemas, with and without the Valsalva maneuver. MATERIALS AND METHODS: Colonic perforations were induced in 135 juvenile pigs. The pigs were divided into five groups, and enemas with air, barium, and water-soluble contrast material were given with and without the Valsalva maneuver to induce the perforations. During the enemas, the Valsalva maneuver was observed when the animals strained. In each animal, the enema was continued and pressure increased until a perforation was detected with fluoroscopy. Radiographic, gross, and histologic examinations of each animal were performed after perforations occurred. Differences in fecal spillage were noted, and the morphologic variations of the perforations and the surrounding tissue were determined. RESULTS: Perforations with hydrostatic (barium, water-soluble) enemas occurred at approximately 120 mm Hg of pressure (average bag height, 57 in. [143 cm]). No significant variations were found between the type of material used for contrast or the use of the Valsalva maneuver. With air enemas, perforations occurred at a mean pressure of 108 mm Hg without the Valsalva maneuver and at 145 mm Hg with the Valsalva maneuver. Perforations during air enemas did not occur during the Valsalva maneuver (pressures as high as 270 mm Hg), but rather between Valsalva maneuvers. Hydrostatic enemas produced full-thickness tears that were larger than those induced by air enemas in all cases. Air enemas with and without the Valsalva maneuver produced partial-thickness tears in 45% and 10%, respectively, of the pigs. Fecal spillage was diffuse in all hydrostatic perforations. In air enemas, spillage was focal in 55% and 90%, respectively, and absent in 45% and 10%, respectively, of perforations produced with and without the Valsalva maneuver. CONCLUSION: Our results suggest that air enemas are safer than liquid enemas. Perforations that occurred during air enemas were smaller and associated with less fecal spillage and peritoneal contamination. The Valsalva maneuver appears to prevent colonic perforation during air enemas.

Air enema for diagnosis and reduction of intussusception: clinical experience and pressure correlates.

Air enema was used for exclusion, diagnosis, initial movement, and complete reduction of intussusception in 186 pediatric patients. Average pressure needed for initial movement of intussusception was 56.5 mm Hg; average maximum pressure of 97.8 mm Hg was required for complete reduction. Average fluoroscopy time required for intussusception reduction was 94.8 seconds; an average of 41.8 seconds was required to exclude intussusception. Intussusception was diagnosed in 75 patients, and reduction was accomplished in 65 (87%). Of 100 consecutive patients that underwent hydrostatic reduction of intussusception at the authors' institution, reduction was successful in 55. Compared with hydrostatic enema, air enema involves shorter fluoroscopy time and lower radiation dose to the patient. Air enema is safe and effective for diagnosis and treatment of intussusception in infants and children and has replaced hydrostatic enema for such procedures at the authors' institution.

Localization and guided removal of soft-tissue foreign bodies with sonography.

Sonography was used to detect, localize, and guide removal of foreign bodies in the soft tissues of the extremities and neck. Twenty localization procedures were performed in 19 patients (12 children and seven adults) with 21 foreign bodies including wood, glass, stone, metal, and lead pencil. Localization was accomplished by using anatomic landmarks, ink marks on the skin, and needle and hemostat markers. Localization was facilitated by the use of small standoff pads that were cut for use on small surfaces. The foreign bodies were visualized as hyperechoic foci with acoustic shadows that were partial or complete depending on the angle of insonation and foreign body composition. Hyperechoic comet-tail artifacts (reverberation artifacts) were seen with six metallic foreign bodies and one glass fragment. Nine foreign bodies were surrounded by hypoechoic halos caused by edema, abscess, or granulation tissue. A slow meticulous scanning technique and high-frequency transducer helped in detection of small foreign bodies. Sonographically guided removal of the foreign body was successful in all four patients in whom it was attempted. Scanning with the ultrasound beam parallel to the long axis of the hemostat and the foreign body was the fastest way to guide the hemostat to the tip of a foreign body. The procedure was accomplished most easily and quickly when one physician performed sonography and hemostat removal of the foreign body simultaneously. Our experience with these cases indicates that sonography is a useful tool in the localization and removal of soft-tissue foreign bodies.

Simple device for air reduction of intussusception.

A new device has been developed for pneumatic reduction of childhood intussusception. The device consists of a reusable, hand-held pressure gauge and insufflator connected to a disposable enema tip and tubing system. The assembled device permits one-handed operation which maximizes operator control of the air reduction procedure. The system has been used to evaluate 50 cases of suspected intussusception. Reduction was successful in 19 of 22 confirmed intussusceptions. This device provides a practical, simple and safe method for diagnosis and treatment of intussusception.

Chronic torsion of the wandering spleen.

Torsion of a wandering spleen can occasionally produce chronic disabling clinical findings that are mistaken for a variety of digestive disturbances. Since the clinical complaints are misleading, a correct and timely radiographic analysis can prevent an extensive but unnecessary pursuit of other more common conditions. Images of an ectopic, enlarged, disoriented spleen with a devitalized parenchyma and adherent pseudocapsule can quickly establish the diagnosis of chronic splenic torsion.

Ovarian dermoid cyst complicated by an entero-ovarian fistula.

An unusual case of a 21-year-old nonpregnant woman with a left ovarian dermoid cyst complicated by an entero-ovarian fistula is presented. This case illustrates the importance of the contrast media enema for detecting this unusual complication.

Concealed pulmonary abscess: diagnosis by computed tomography.

During childhood, an acute pneumonia with bulging margins usually reflects an abundant production of exudate. However, an unexplained persistence of an expansile pneumonia following therapy indicates that the infectious process may be isolating itself by forming an abscess. Previous reports emphasize that such abscesses are rarely diagnosed prior to thoracotomy or autopsy. Computed tomography facilitates an earlier disclosure of an abscess or empyema that is producing a persistent but unexplained expanding opacification on plain film.

Ileocolic intussusception: hydrostatic reduction in the presence of the dissection sign.

Hydrostatic reduction of an ileocolic intussusception has not been reported when barium dissects around the intussusceptum as opposed to pushing it retrograde. Consequently, this development is considered an indication to discontinue hydrostatic reduction. We have studied a baby in whom draining the colon caused a seemingly irreversible dissection of barium to disappear so that hydrostatic reduction of the intussusception was easily accomplished when the colon was refilled with barium.