Suspected appendicitis in children: focused CT technique for evaluation.

PURPOSE: To determine the accuracy of a focused computed tomographic (CT) technique with oral and intravenous contrast materials for the diagnosis of appendicitis. MATERIALS AND METHODS: Ninety-three abdominal-pelvic contrast material-enhanced CT scans obtained during 6 years in 54 girls and 39 boys (age range, 1-18 years) with right lower quadrant pain were retrospectively reviewed. The detected abnormal findings were recorded as being in the region above the upper pole of the right kidney, between the upper pole of the right kidney and the lower pole of the right kidney (RLP), or below the iliac crest. Sensitivity, specificity, and positive and negative predictive values were calculated. chi(2) analysis was performed to determine whether there were significant differences among patient groups according to region of detected disease. RESULTS: Fifty-five scans were abnormal: 38 showed appendicitis; and 17, other diseases. No scans, except two that showed pneumonia, had key findings above the RLP. Nineteen scans showed key findings between the RLP and the iliac crest. Thirty-three scans had diagnostic findings only below the iliac crest. The sensitivity (97%), specificity (93%), positive predictive value (90%), and negative predictive value (98%) of interpretation with all images for the diagnosis of appendicitis were the same as those of interpretation with only the focused images. CONCLUSION: CT performed to diagnose appendicitis can be limited to the region below the RLP.

Abdominal MR imaging with a volumetric interpolated breath-hold examination.

PURPOSE: To compare a T1-weighted, three-dimensional (3D), gradient-echo (GRE) sequence for magnetic resonance (MR) imaging of the body (volumetric interpolated breath-hold examination, or VIBE) with a two-dimensional (2D) GRE breath-hold equivalent. MATERIALS AND METHODS: Twenty consecutive patients underwent 1.5-T MR imaging. The examinations included pre- and postcontrast (20 mL gadopentetate dimeglumine) fat-saturated 2D GRE breath-hold imaging and fat-saturated volumetric interpolated breath-hold imaging before, during (arterial phase), and after injection, with thin (2-mm source images) and thick (8-mm reconstruction images) sections. The three images were compared qualitatively and quantitatively (signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]). RESULTS: Qualitatively, the 2-mm source images had poorer pancreatic edge definition on precontrast images compared with the other two data sets (P < .05). On gadolinium-enhanced images, scores for clarity of pancreatic edge, number of vessels visualized, and arterial ghosting were significantly lower for the postcontrast 2D GRE images. Quantitatively, SNR measurements in the liver, aorta, and renal cortex on pre- and postcontrast images were significantly higher for the 8-mm reconstruction images than for the 2D GRE or 2-mm source images (P < .05). Aorta-to-fat CNR was significantly higher on the 8-mm reconstruction images. CONCLUSION: Fat-saturated volumetric interpolated breath-hold images have quality comparable to that of conventional fat-saturated 2D GRE images.

MR findings in Shone's complex of left heart obstructive lesions.

BACKGROUND: Shone's complex is a series of four obstructive or potentially obstructive left-sided cardiac lesions (supravalvular mitral ring, parachute deformity of the mitral value, subaortic stenosis, and coarctation of the aorta). Both the complete form (all four lesions) and incomplete forms (less than four lesions) have been described. OBJECTIVE: To determine which abnormalities of Shone's complex could be characterized by MR. MATERIALS AND METHODS: MR examinations in three patients (one complete, two incomplete) were retrospectively reviewed. RESULTS: A supravalvular mitral ring, found at surgery in one patient, was not identified. Regurgitant and stenotic flow across the mitral valve, abnormal motion of the valve leaflets and abnormalities of the papillary muscles were identified. Individual chordal attachments were difficult to resolve. Narrowing in the subaortic region and abnormal flow from the subaortic region through the valve plane were demonstrated. A discrete subaortic diaphragm in one patient was not resolved. Both focal and diffuse types of coarctation of the aorta were well characterized. CONCLUSION: MR imaging is suited to evaluation of patients with Shone's complex. Individual chordal attachments and thin diaphragms of the mitral and aortic valves were difficult to resolve.

Resonance imaging of a ruptured aneurysm of the sinus of Valsalva.

Ruptured aneurysm of an aortic sinus of Valsalva is a rare cause of left-to-right shunting. We show how resonance imaging can be used to make the diagnosis. This technique can successfully characterize the shunt as well as determine the presence of associated anomalies, such as ventricular septation and aortic regurgitation. It may be the only study required prior to therapeutic intervention.

Retroperitoneal pulmonary sequestration: imaging findings, histopathologic correlation, and relationship to cystic adenomatoid malformation.

OBJECTIVE: Retroperitoneal bronchopulmonary sequestrations are rare congenital lesions that have been increasingly reported as incidental findings in utero. We present our case material of congenital retroperitoneal sequestration, discuss the reported imaging and histopathologic characteristics of this entity, and provide an approach to subsequent clinical and surgical management. CONCLUSION: Our data suggest that the imaging findings in retroperitoneal sequestration are characteristic and that faulty mesenchymal induction of pulmonary tissue within the retroperitoneum renders internal development into cystic adenomatoid malformation the rule rather than the exception. In the typical case, surgical removal is nonemergent.

Comparison between in-phase and opposed-phase T1-weighted breath-hold FLASH sequences for hepatic imaging.

PURPOSE: Our goal was to compare in-phase (IP) and opposed-phase (OP) sequences for GRE breath-hold hepatic imaging. METHOD: Non-contrast-enhanced IP and OP GRE breath-hold images were obtained in 104 consecutive patients referred for abdominal MRI at 1.0 T. For both sequences, the TR, FA, matrix, FOV, slice thickness, interslice gap, and measurements were kept constant. Images were compared quantitatively [liver/spleen and liver/lesion signal difference/noise ratio, (SD/N)] and qualitatively (artifacts, lesion detection and conspicuity, and intrahepatic anatomy). RESULTS: There was no statistically significant difference when comparing IP and OP sequences for liver/spleen and liver/lesion SD/N or for the qualitative parameters. In patients with fatty infiltration, the OP sequences yielded substantially lower values for liver/spleen and liver/lesion SD/N (0.9 and -1.2, respectively) than the IP sequences (20 and 17, respectively). Furthermore, in several cases with fatty infiltration, many more lesions were identified using IP images. CONCLUSION: The use of IP and OP GRE sequences provides complementary diagnostic information. Focal liver lesions may be obscured in the setting of fatty infiltration if only OP sequences are employed. A complete assessment of the liver with MR should include both IP and OP imaging.

Pediatric hepatic CT: an injection protocol.

OBJECTIVE: To determine an injection protocol for pediatric hepatic CT and to investigate the use of power injection. MATERIALS AND METHODS: Eighty-seven studies were prospectively performed using ioversol (320 mg iodine per cc) at 2 cc/kg. Three techniques were used: helical (1 s/slice); dynamic, non-breath-hold (5.5 s/slice); dynamic, breath-hold (10 s/slice) scans. The liver-scan time for each study was determined. Scan initiation ranged from 25 to 80 s. An injection duration (50-100 seconds) was selected. From the contrast volume (2 cc/kg x kg body wt) and injection duration, the injection rate (cc/s) was calculated for each patient. Each study was grouped by injection rate corrected for body weight (cc/kg/min) into: 1.2-1.5, 1.51-2.0, and 2.01-2.4. The aortic/liver attenuation curves were plotted for each group. RESULTS: Liver-scan time for helical studies was a mean of 26 s, for dynamic, non-breath-hold studies 75 s, dynamic breath-hold scans were 154 s. Injection rates of 1.2-1.5 cc/kg/min produced a scanning interval of 165 s. Injection rates of 1.51-2.0 cc/kg/min produced a scanning interval of 120 s. Injection rates of 2.01-2.4 cc/kg/min produced a scanning interval of 90 s. There was no increase in hepatic attenuation for the injection rates 2.01-2.4 cc/kg/min compared with 1.51-2.0 cc/kg/min. There was one complication related to injection through a central line. CONCLUSIONS: An injection protocol was determined for helical studies with injection rates of 1.7-2.0 cc/kg/min with initiation at 60 s; for dynamic, non-breath-hold studies with injection rates of 1.5-1.7 cc/kg/min with initiation at 50 s; and for dynamic breath-hold studies with injection rates of 1.2-1.5 cc/kg/min with initiation at 45 s. Power injection was used safely in our population.

Traumatic abdominal pseudoaneurysm secondary to child abuse.

Traumatic injury to the descending thoracic and abdominal aorta is uncommon in children and is usually secondary to recognized blunt trauma. Child abuse has not been previously reported as a cause. We report a 3-year-old boy who was kicked in the abdomen by his father. A resulting pseudoaneurysm was successfully resected.

T2-weighted MR imaging of the chest: comparison of electrocardiograph-triggered conventional and turbo spin-echo and nontriggered turbo spin-echo sequences.

In 22 patients with a diverse range of thoracic abnormalities, T2-weighted magnetic resonance (MR) images of the chest were obtained with electrocardiograph (ECG)-triggered turbo spin-echo (TSE), ECG-triggered conventional spin-echo (CSE), and nontriggered TSE sequences, and the images were compared. A 5-point rating scale was used by three radiologists experienced in MR imaging of the chest to independently evaluate the images for (a) freedom from ghosting, (b) clarity of heart wall and cardiac chambers, (c) clarity of mediastinal structures, (d) conspicuity of abnormalities, and (e) overall image quality. Evaluations were analyzed with statistical methods. For freedom from ghosting, clarity of heart wall and cardiac chambers, clarity of mediastinal structures, and overall image quality, the ECG-triggered TSE images were rated higher than the TSE images, which, in turn, were rated higher than the ECG-triggered CSE images at the P = .05 level of significance. No significant differences were seen between the pulse sequences in the conspicuity of abnormalities, although some differences were observed in individual cases. Our results suggest that ECG-triggered TSE imaging provides improved, time-efficient T2-weighted images of the chest.

Common bile duct in children: sonographic dimensions.

PURPOSE: To determine the normal caliber and rate of growth of the extrahepatic biliary ducts in the pediatric population. MATERIALS AND METHODS: The diameter of the common bile duct was measured with sonography in 173 children aged 1 day to 13 years (mean, 6.0 years; median, 5.0 years) who were examined for reasons other than hepatic or biliary tract disease. Results were subjected to regression analysis and compared with similar measurements of the extrahepatic portal vein and hepatic artery. The size of the gallbladder was subjectively estimated as distended, moderately full, and contracted. Differences in the diameter of the common bile duct in these three groups were evaluated with the Mann-Whitney U test. RESULTS: The average diameter of the common bile duct in this population was 1.27 mm +/- 0.67 (< 3.3 mm in all patients and < 1.2 mm in children aged 3 months or less). The slope of the curve describing the growth of the common bile duct was relatively flat, similar to that of the hepatic artery and half that of the portal vein. There was a significant difference in the diameter of the common bile duct between patients with distended gallbladders and those with contracted gallbladder (P = .02). CONCLUSION: The pediatric common bile duct is significantly smaller than adult norms; it is a distensible structure responsive to fluctuations in prandial bile flow.

The antral nipple sign of pyloric mucosal prolapse: endoscopic correlation of a new sonographic observation in patients with pyloric stenosis.

This study describes the antral nipple sign of pyloric mucosal prolapse, a newly delineated sonographic observation in patients with pyloric stenosis, correlates the endoscopic findings, and examines its prevalence and significance in 31 consecutive patients with pyloric stenosis. Fifty patients who did not have pyloric stenosis served as the control population. The antral nipple sign consists of visualization of prolapsed, hypertrophied pyloric mucosa protruding into the gastric antrum. Using the Wilcoxon scores (rank sums), there was no significant difference among the patients in age, weight, or pyloric muscle dimensions. Although the diagnosis of pyloric stenosis is made on the basis of muscle thickness, we have documented that the pyloric mucosa becomes redundant in infants with pyloric stenosis, permitting a fuller understanding of the anatomic correlate underlying the sonographic images.

Application of thin-section low-dose chest CT (TSCT) in the management of pediatric AIDS.

The aim of this study was to evaluate the usefulness of thin-section low-dose computed tomography (TSCT) in the management of children with AIDS, as chest radiographs (CXR) often fail to adequately explain the patients' clinical status. We performed 54 noncontrast TSCTs on 32 children. The patients aged from 3 months to 14.6 years, were diagnosed as having bacterial pneumonia, lumphocytic interstitial pneumonitis (LIP), Pneumocystis carinii pneumonia (PCP), or Mycobacterium avium-intracellulare infection (MAI). The scans were correlated with the clinical diagnosis, T-lymphocyte-subset percentages, and p24-antigen levels. Subsegmental consolidations were seen in patients with LIP, PCP, and MAI, and as an isolated finding in those with only bacterial pneumonia. Ground-glass haziness was seen exclusively with acute PCP. Reticulonodular thickening was identified only in patients with LIP. Mosaic perfusion was seen with MAI, LIP, and pneumonia. The presence of adenopathy correlated with CD4+ T-cell subset percentages. The greatest value of CT in this study was in detecting new disease when chest films failed to correlate with a patient's clinical state, and in demonstrating acute/subacute disease in patients with severe baseline chest-film changes. Recurrent pneumonias may represent progression of "smoldering" disease, rather than true recurrent disease following complete clearing. Adenopathy with low CD4+ levels should suggest lymphoma or infection with MAI.

Hypertrophic pyloric stenosis in the infant without a palpable olive: accuracy of sonographic diagnosis.

PURPOSE: To evaluate the accuracy of sonography for both diagnosis and exclusion of pyloric stenosis in the infant with nonbilious vomiting without a palpable olive and to clarify the relationship between infant age and size and the dimensions of the hypertrophic pylorus. MATERIALS AND METHODS: The sonograms of 152 infants with suspected pyloric stenosis were evaluated. The prospective diagnoses were categorized as pyloric stenosis, normal pylorus, and pylorospasm with potential to progress to pyloric stenosis. Positive findings were confirmed at surgery; negative findings were confirmed by means of chart review. RESULTS: Sensitivity, specificity, and accuracy of sonography in determination of appropriate surgical referral were 100%. A significant (P < .05) correlation was found between the size of the hypertrophied muscle and the age of the patient at initial examination. CONCLUSION: Sonography is highly sensitive and, in this patient population, highly specific, and by virtue of direct visualization of the pyloric muscle, it is the method of choice for both diagnosis and exclusion of pyloric stenosis.

Effect on fetal mouse development of exposure to MR imaging and gadopentetate dimeglumine.

Pregnant mice were exposed to one of five regimens at 9.5 days of gestation: no treatment (group 1), intraperitoneal injection of normal saline (group 2), intraperitoneal injection of gadopentetate dimeglumine (group 3), intraperitoneal injection of gadopentetate dimeglumine and magnetic resonance (MR) exposure (group 4), and MR exposure alone (group 5). At 18 days of gestation, the mice were sacrificed and fetuses were removed and examined for the following end points: litter size, number alive or dead, fetal weight, extremity morphology, eye and ear development, and appearance of the head. A total of 739 fetuses were analyzed: group 1 (n = 161), group 2 (n = 149), group 3 (n = 142), group 4 (n = 136), and group 5 (n = 151). The only statistically significant difference was a lower mean fetal weight in the saline-injection group compared with the control group. The results show that MR exposure with and without gadopentetate dimeglumine had no adverse effect on the end points analyzed.

The role of flexible bronchoscopy in children with AIDS: an update of the New York University experience.

The clinical courses of children with acquired immunodeficiency syndrome (AIDS) who underwent diagnostic flexible bronchoscopy at Bellevue Hospital from 1987-1992 were reviewed to determine the value of the procedure in patient management. Twenty-eight children (age 13 days to 12 years) underwent 31 bronchoscopies for indications including respiratory distress, fever and abnormal chest radiograph. Procedures were well tolerated. Complications were limited to transient hypoxia and epistaxis. Although 58% of bronchoscopies yielded a diagnosis (Pneumocystis carinii, Streptococcus viridans, Pseudomonas aeruginosa, Cytomegalovirus, atypical mycobacterium, giant cell pneumonia, and mechanical obstruction), empiric medical therapy was altered in only 16% of cases. Bronchoscopic diagnoses are correlated with Centers for Disease Control (CDC) classification, immune status, treatment and outcome.

Monitoring of girls undergoing medical therapy for isosexual precocious puberty.

We evaluated the use of sonography in monitoring the efficacy of suppressive therapy with a gonadotropin releasing hormone analogue in girls being treated for isosexual precocious puberty. Ten girls 5 to 9 years of age underwent serial sonography and hormonal stimulation tests on the same day. Sonographic trends of decreasing ovarian volume and uterine length indicated early suppression even when absolute values were above threshold. Changes in ovarian volume were the most sensitive predictor of pituitary-gonadal suppression. Sonography is a sensitive and accurate method of monitoring medical therapy; ovarian volume and analysis of interval change are the most sensitive barometers of change.

Renal cell carcinoma: correlation of CT findings with nuclear morphologic grading in 100 tumors.

The contrast-enhanced preoperative computed tomographic (CT) scans and microscopic slides of 94 patients with 100 surgically resected renal cell carcinomas (RCCs) were retrospectively and independently reviewed in order to correlate the CT imaging findings of RCC with nuclear grading. As nuclear grade increased, RCCs were more likely to be of higher stage and greater size at presentation, and appeared more heterogeneous and less marginated. Of the features analyzed, tumor margination most closely correlated with nuclear grade. Overlap in the CT appearance of individual tumors limited the potential of CT to differentiate RCCs of varying grade. Small, well-marginated, homogeneous tumors, however, were either grade I or II, and were distinguishable from the more aggressive grade III lesions, which generally displayed irregular margins and greater inhomogeneity.

Feasibility of high-resolution, low-dose chest CT in evaluating the pediatric chest.

Thin-section, high-resolution (1.0/1.5 mm thick slices), low-dose chest CT scans were performed in 55 infants and children. The studies were carried out with 1- and 2-s scan (data acquisition) times using a high-resolution (bone) algorithm. Although there was some motion artifact, the studies provided valuable information for evaluating diffuse parenchymal lung disease. The thin slices provided finer detail and more diagnostic information than images representing thicker sections. Most studies were performed using between 40 and 80 mAs. It is estimated that the patients' radiation exposure was 20% that of conventional high-resolution CT (HRCT) and 57% that of routine chest CT. Diagnostic HRCT scans can be obtained in infants and young children without the need for suspended respiration or specialized ultrafast CT scanners.

Opportunistic infections and tumors in immunocompromised children.

HIV infection is responsible for a major proportion of the immunodeficiency disease seen in the pediatric population. The radiologic findings are varied and generally non-specific. The development of secondary neoplasms may present new diagnostic and therapeutic challenges as therapy for superimposed infections becomes more successful.