Aslam R. Siddiqui

Gastroesophageal reflux in infants and children-comparative accuracy of diagnostic methods*

To assess the diagnostic accuracy of methods employed for detection of gastroesophageal reflux, 30 infants and children with symptoms of GER were evaluated by upper gastrointestinal series, gastroesophageal scintiscan, measurement of mean resting lower esophageal sphincter pressure, esophageal intraluminal PH measurement (acid reflux test), and endoscopy. Fifteen control patients were also evaluated by the above studies. GER was demonstrated by UGI in 15 and by GE scintiscan in 17 study patients. LESP less than 15 mm Hg was noted in 12 and a positive acid reflux test was obtained in 29 study patients. Esophagitis was detected in two (of 30) study patients radiographically and in 15 (of 21) study patients by upper gastrointestinal endoscopy. Pulmonary aspiration of gastric contents was not detected by the radionuclide method. None of the 15 control patients had GER demonstrated with any of the above methods. These studies indicate that (1) the acid reflux test correlates most closely with symptoms of GER; (2) THE GE scintiscan is complementary to the UGI in the diagnosis of GER, i.e., the combination increases sensitivity; (3) normal LESP does not necessarily exclude GER; and (4) endoscopy is superior to the UGI in detecting the presence of esophagitis.

Acute pyomyositis of the pelvis: the spectrum of clinical presentations and MR findings

Background: Acute pelvic pyomyositis is uncommon in non-tropical areas. Objective: To summarize the clinical and MR findings in children with acute pelvic pyomyositis. Materials and methods: We retrospectively identified 20 children (mean age 9.4 years) who were evaluated by MR and diagnosed with acute pelvis pyomyositis during the time period between January 2002 and June 2005. We reviewed clinical, laboratory, and imaging findings. Results: Fifteen of the 20 children had secondary pyomyositis associated with osteomyelitis (n=13), septic hip (n=4) or sacroiliitis (n=4); all were previously healthy except for one child with leukemia. Seven of the children with secondary pyomyositis underwent bone scintigraphy; three (43%) did not show pelvic abnormalities. Staphylococcus aureus was cultured in 13 of the 15 (87%) children. Five of the 20 children had primary pyomyositis. Three had underlying disease and two others were engaged in vigorous physical activity. Bone scintigraphies (n=2) were negative. Cultures were positive for S. aureus in three of the five (60%) children. Conclusion: Septic hip should be the first diagnostic consideration in children with fever and acute hip pain. Pyomyositis should be considered if art\hrocentesis is negative or there is clinical suspicion of infection outside the hip joint. MR is the preferred imaging modality for evaluating foci of pyomyositis, muscle abscesses, and additional foci of infection within the pelvis.

Impaired immune function in obstructive jaundice

Sepsis is a common and occasionally lethal complication of obstructive jaundice. The reasons for this increased susceptibility to infection are unknown. This study examines lymphocyte and reticuloendothelial (RES) function in animals with obstructive jaundice. Twelve New Zealand white rabbits (3-4 kg) were studied. Lymphocyte function was evaluated in six rabbits by phytohemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM) stimulation. In six animals, hepatic RES function was assessed by calculating the phagocytic index (PI) using the disappearance of 99Tc sulfacolloid (5 mg/kg) iv. After baseline studies, the common bile duct was divided and ligated. The above studies and serum bilirubin were repeated at 3 weeks. Obstruction was then relieved by cholecystojejunostomy (CJ) and RES studies repeated monthly x 6. Preobstructive lymphocyte function showed a stimulation index ratio (log) of 0.85 +/- 0.25 for PHA, 0.75 +/- 0.3 for Con A, and 0.71 +/- 0.25 for PWM. With biliary obstruction, the values fell to -0.23 +/- 15 (P less than 0.006), -0.31 +/- 0.12 (P less than 0.006), and -0.29 (P less than 0.006), demonstrating impaired lymphocyte function. When tested lymphocytes were mixed with control pooled rabbit serum, however, no lymphocyte impairment was noted. Baseline hepatic PI was 6.02 +/- 0.18 and fell to 3.79 +/- 0.33 with obstruction (P less than .01) and remained low at (3.20 +/- 0.14) 1 month (P less than 0.01) and (3.33 +/- 0.23) at 3 months (P less than .01), after CJ but returned to normal (8.04 +/- 0.97) at 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Osteomyelitis and pyogenic infection of the sacroiliac joint. MRI findings and review.

Acute pyogenic sacroiliac joint infection and osteomyelitis of adjacent bones often present with severe, poorly localized lower back, pelvic or hip pain. Five cases of sacroiliac joint infection or sacroiliac bone osteomyelitis were evaluated by MRI. MRI may be a helpful diagnostic tool to evaluate early changes of infection in the sacroiliac area. It is very sensitive for detecting bone marrow abnormalities; however, it is nonspecific and can not accurately differentiate osteomyelitis from sacroiliitis.

The role of pelvic magnetic resonance in evaluating nonhip sources of infection in children with acute nontraumatic hip pain.

We retrospectively identified all children with acute hip pain who underwent pelvic magnetic resonance (MR). Children with septic hip or history of trauma were excluded; the remaining children with signs of infection (fever, >38°C; leukocytosis, >12 × 109/L; or elevated erythrocyte sedimentation rate [ESR], >30 mm/h) comprised the study group. Thirty-three children (9 girls; age, 0.8-15.8 years) were identified. On MR examination, 18 (55%) of 33 children had hip joint effusion, whereas 19 (58%) of 33 children had other abnormalities, including pyomyositis (n = 15), osteomyelitis (n = 12), and sacroiliitis (n = 3). Staphylococcus aureus was cultured from 13 (68%) of these 19 children. Compared with MR, sensitivity for bone and soft tissue abnormalities was 30% for pelvic radiography (n = 26) and 71% for bone scintigraphy (n = 8). Elevated ESR (>30 mm/h) was the clinical finding that best predicted pelvic osteomyelitis or pyomyositis. Pelvic MR should be performed to rule out pelvic osteomyelitis or pyomyositis in children with acute hip pain, ESR of more than 30 mm/h, and no evidence of septic hip.

Feasibility of low doses of I-131 for thyroid ablation in postsurgical patients with thyroid carcinoma

The feasibility of using low doses of l-131 (30 mCi) for ablation of thyroid remnants following surgery for papillary and follicular thyroid carcinoma was examined in 21 patients. Six weeks following near-total thyroidectomy and three days following intramuscular thyroidstimulating hormone (10 IU), patients were given 30 mCi of l-131 and scans were performed 24 to 72 hours later. Remaining thyroid tissue was identifiable in the thyroid bed in 19 patients, and two patients also had evidence of cervical metastases. Patients with metastases received an additional 100 mCi of l-131. Follow-up l-131 scans were performed at nine to 15-month intervals in ten patients who initially received 30 mCi of l-131, and only one patient showed complete ablation of the residual thyroid tissue, whereas the remaining nine patients had persistent uptake of l-131 in the same regions in which the uptake was seen in the initial postoperative scans. One of the nine patients had evidence of a cervical metastasis as well. It is therefore apparent that total or near-total thyroidectomy rarely removes all thyroid tissue and that an “out-patient” dose of l-131 is not adequate for ablation of postoperative thyroid remnants.

The value of good medical student teaching: Increasing the number of radiology residency applicants

RATIONALE AND OBJECTIVES The authors attempted to define the value of good medical student teaching to the profession of radiology by examining the effect of radiology course improvements on the number of 4th-year students applying to radiology residencies. MATERIALS AND METHODS Course evaluation and residency application data were obtained from six consecutive classes of 4th-year medical students at the study institution, and these data were compared with national data. RESULTS Between 1995 and 2000, the number of 4th-year U.S. medical students applying to radiology increased 1.6 times. At the study institution, that number increased 4.5 times, a statistically significant difference (P = .020, chi2 test). Student survey data indicate that this increase reflects a general increase in the quality of radiology teaching in the study institution and specific changes in a required 2nd-year medical school course. CONCLUSION These results strongly suggest that good medical student teaching pays important dividends, not only to the departments that provide it but also to the profession of radiology as a whole. Exposing students to good radiology teaching early in their medical school careers is especially important. Radiology departments that provide outstanding medical student education should be studied to help develop a model of educational best practices.

Clinical applications of technetium Tc 99m hexamethyl propylene amine oxime leukocyte scan in children with inflammatory bowel disease

BACKGROUND Labeled leukocyte imaging is a helpful diagnostic tool in the detection of inflammation and sepsis. The technetium Tc 99m hexamethyl propylene amine oxime (99mTc HMPAO)-labeled leukocyte scan has been found to be more sensitive than the Indium-111 labeled leukocyte scan in detecting inflammatory bowel disease, with reported sensitivities of 95% to 100%. Experience with the 99mTc HMPAO-labeled leukocyte scan was examined and its clinical applications evaluated in the immediate treatment of patients with inflammatory bowel disease. METHODS A retrospective chart review was undertaken that included pediatric patients who underwent 99mTc HMPAO-labeled leukocyte scan at the James Whitcomb Riley Hospital for Children. The disease activity of patients with inflammatory bowel disease was assessed. The leukocyte scan was performed according to the manufacturers specifications, and images were obtained 30 minutes and 2 hours after administration of the radiopharmaceutical. RESULTS During the period of July 1996 through November 1997, 41 scans were performed in 35 patients. Twenty-nine patients had histologically proven inflammatory bowel disease: 24 with Crohns disease, 4 with ulcerative colitis, and 1 with indeterminate colitis. Active inflammatory bowel disease was suspected in 24 patients when the leukocyte scan was performed. Twenty of the 24 patients (83% sensitivity) had abnormal findings in leukocyte scans that prompted more aggressive management in 15 (75%). Six of the 15 who were receiving maximum medical therapy underwent surgical resection of severely affected bowel segments, and medical treatment was intensified in the other 9. The remaining 5 patients were receiving optimal medical therapy, instituted at their recent visit, and did not require further medication adjustments. Four of the 24 patients with active inflammatory bowel disease had normal leukocyte scans (17% false-negative rate), 3 of whom were receiving corticosteroid therapy at the time the scans were performed. All of the 11 patients in whom inflammatory bowel disease was in remission and 6 patients who did not have inflammatory bowel disease had normal findings in leukocyte scans (100% specificity). CONCLUSIONS Although a tissue diagnosis is still recommended, obtained during upper and lower gastrointestinal endoscopic examinations, and contrast radiography of the small bowel for the initial work-up of patients with suspected inflammatory bowel disease, the 99mTc HMPAO-labeled leukocyte scan is a safe and useful diagnostic adjunct for subsequent evaluation of patients known to have inflammatory bowel disease. The results of 99mTc HMPAO-labeled leukocyte scans directly influenced treatment of 75% of the study patients with active inflammatory bowel disease, which included the decision to refer patients for surgical intervention.

The role of bone scintigraphy in osteogenic sarcoma.

Hospital records of 27 children with osteogenic sarcoma were reviewed in an effort to define the usefulness of skeletal scintigraphy in the initial evaluation and follow-up of their disease. Serial bone scans as well as plain radiographs, linear tomograms, and computed tomograms were evaluated for evidence of bone or lung metastases. Eighteen patients developed lung metastases and three developed bone metastases. Seven patients demonstrated uptake of tracer in lung metastases, however, the lesions were all easily identifiable by radiographic means. All bone metastases were detected by scintigraphy, in one instance prior to radiographic abnormality. In no cases were bone metastases known to occur in the absence of lung metastases. None of the bone scans performed for routine follow-up pruposes resulted in altered therapy for the patient. We propose that skeletal scintigraphy is useful in the initial metastatic work up of osteogenic sarcoma, and may be helpful in some patients with specific indications during their follow-up, but is less valuable when there is no clinical suspicion for bone metastases.

Comparison of technetium-99m sulfur colloid and in vitro labeled technetium-99m RBCs in the detection of gastrointestinal bleeding

Twenty-seven paired Tc-99m sulfur colloid (SC) and Tc- 99m RBC studies were evaluated for the detection of Gl bleeding. The only two positive Tc-99m SC studies had positive early Tc-99m RBC studies as well. There were 15 other positive Tc-99m RBC studies (three during the first hour) and these were associated with normal Tc- 99m SC scans. Approximately 70% of the positive Tc- 99m RBC studies occurred after 1 hour. Tc-99m RBCs should be the initial test in patients with Gl bleeding.