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Biomedical subjects

J C Leonidas

Publications and source records attributed to J C Leonidas.

At least 19 recordsLinked to original sources
PubMed1995

Papillary-cystic neoplasm of the pancreas.

Papillary-cystic neoplasm of the pancreas is a rare, nonfunctioning low-grade malignant tumor seen in young patients, most often female. Ultrasound and CT show a circumscribed, solid nonhomogeneous mass with cystic areas, with peripheral but not central enhancement and occasional calcification. Prognosis after excision is usually excellent. We describe a case of the papillary-cystic neoplasm of the pancreas in a 13-year-old girl to illustrate the radiological findings.

Adolescent↗
PubMed1994

Severe cystic pulmonary disease associated with chronic Pneumocystis carinii infection in a child with AIDS.

A 3-year-old HIV-positive boy developed Pneumocystis carinii pneumonia (PCP) resulting in chronic interstitial pulmonary disease, which persisted for the following 3 years; he was essentially asymptomatic and the lung findings had therefore been attributed to lymphocytic interstitial pneumonia (LIP). He subsequently developed extensive cystic pulmonary disease, documented by CT, leading to recurrent pneumothorax and severe pulmonary insufficiency. Lung biopsy revealed chronic PCP infection associated with extensive pulmonary fibrosis and calcification. This case suggests that Pneumocystis carinii may cause chronic progressive pulmonary fibrosis with cyst formation and respiratory failure.

AIDS-Related Opportunistic Infections↗
PubMed1994

Sonographic diagnosis of acute appendicitis in children.

The authors performed graded compression abdominal ultrasound (US) examinations in children with suspected acute appendicitis, whose clinical presentation was atypical. Abdominal US examination results were 95% accurate, far exceeding that reported for other imaging modalities. The sensitivity was 86%, the specificity was 98%, and the positive and negative predictive values were 96% and 94%, respectively. A positive sonogram made the likelihood of acute appendicitis 50 times greater compared with the pretest clinical impression. In addition, the use of US permitted identification of other pathological conditions that manifest similar symptoms and signs. The authors conclude that, with proper experience, US can be extremely useful in assisting the surgeon to markedly decrease the number of unnecessary appendectomy procedures, without increasing the risk of perforation.

Abdomen↗
PubMed1994

Pancolonic disease in cystic fibrosis and high-dose pancreatic enzyme therapy.

We describe a child with cystic fibrosis who was treated with high-dose pancreatic enzyme replacement therapy and who had a prominent ascending colon stricture with submucosal fibrosis. Unlike prior reported cases, this patient's disease was more extensive, involving the entire colon, and was associated with chylous ascites.

Child, Preschool↗
PubMed1993

Comparison of CT and MRI in the evaluation of therapeutic response in thoracic Hodgkin disease.

Current imaging modalities are accurate in establishing the diagnosis and extent of thoracic Hodgkin disease. After treatment, however, it is extremely difficult to differentiate potential residual active neoplastic disease from scar tissue, or identify early recurrence. We evaluated the contribution of MRI in the assessment of the response to treatment of thoracic Hodgkin disease in the assumption that scar formation would be characterized by low signal intensity in all pulse sequences, whereas active tumor should maintain a degree of high signal intensity on T2-weighted images. In 47 occasions (23 patients) both CT and MRI were able to identify correctly active disease, but had low specificity in confirming remission because of residual tissues masses. High signal intensity on T2-weighted MR images often persisted despite remission, probably because of edema, necrosis, granulation or other factors. MRI was somewhat more specific than CT and may be quite valuable to confirm remission in patients with residual masses that no longer appear hyperintense on T2 after treatment.

Adolescent↗
PubMed1993

Ovarian microcysts in girls with isolated premature thelarche.

We compared the frequency of ovarian microcysts in girls with premature thelarche (n = 27) to that in age-matched control subjects (n = 24). There was an increased prevalence of detectable ovarian microcysts in girls with premature thelarche. The presence or absence of cysts did not correlate with basal gonadotropin or estradiol levels.

Breast↗
PubMed1993

Marrow space imaging in Hodgkin's disease. MRI prior to biopsy for improved accuracy.

PURPOSE: Accurate staging of Hodgkin's disease is essential for choosing appropriate therapy. PATIENTS AND METHODS: A case of a 13-year-old boy with a history of Hodgkin's disease and negative iliac crest biopsies is presented. RESULTS: MRI-guided biopsy led to the accurate diagnosis of bone marrow involvement and a change in patient management. CONCLUSIONS: Magnetic resonance imaging has the potential to detect focal marrow involvement and therefore direct biopsy site.

Adolescent↗
PubMed1991

Magnetic resonance imaging in the diagnosis of adolescent colorectal carcinoma.

A 14-year-old girl presented with a large abdominal mass, thought to be an ovarian tumor on the basis of clinical and sonographic findings. MRI correctly suggested a primary colonic neoplasm. At operation, ovarian involvement was found to be secondary to metastatic signet ring cell adenocarcinoma of the colon, an extremely rare malignancy in this age group. Low index of suspicion for this tumor in children and adolescents results in advanced disease at diagnosis and poor prognosis. Early imaging with MRI is recommended when the nature of pelvic disease in children remains obscure.

Adenocarcinoma, Mucinous↗
PubMed1991

Granulomatous hepatitis in cat-scratch disease. Ultrasound and CT observations.

A male two year old was admitted to the hospital with a one month history of fever. The physical examination was unrevealing. Abdominal ultrasound revealed multiple, circumscribed regions of low attenuation in the liver and a parapancreatic mass. Laparotomy and biopsy revealed multiple nodules in the liver. The histopathologic findings indicated the child had cat-scratch disease, which resolved with administration of gentamycin sulfate.

Cat-Scratch Disease↗
PubMed1991

Sonographic abnormalities of the thyroid gland in longterm survivors of Hodgkin disease.

We studied the thyroid gland in 18 long term survivors of Hodgkin Disease, all of whom received radiation therapy (2400-4000 cGy, mean 3434). Evaluation included clinical examination, thyroid function tests, ultrasound, as well as selective use of nuclear scintigraphy. The time interval post radiation was 1-16 years (mean 6.4 years). Clinical evaluation and thyroid function tests were insensitive in detecting abnormalities and most nodules were non palpable. Ultrasound detected abnormalities in 16 patients (89%) including diffuse atrophy (n = 6), solitary nodules (n = 4), multiple nodules (n = 5) and gland heterogeneity with calcification in one patient. Cold nodules on nuclear scintigraphy (n = 4) were subjected to biopsy. Multiple foci of papillary carcinoma were found in one patient. There was a tendency for nodules to increase in number as the post radiation interval also increased. We recommend frequent sonographic evaluation and early suppression of thyroid stimulation in an attempt to arrest the development of neoplastic changes.

Adolescent↗
PubMed1991

Midgut volvulus in infants: diagnosis with US. Work in progress.

The authors present findings from ultrasound (US) studies that can alert sonologists to the possibility of midgut malrotation complicated by volvulus in neonates and infants. A fluid-filled, distended duodenum seen at US examination in infants is a nonspecific sign of duodenal obstruction, as well as one of the signs of midgut malrotation. In addition, dilated, thick-walled bowel loops, mainly to the right of the spine, and peritoneal fluid were found at abdominal US examinations of three infants with midgut malrotation complicated by volvulus. In one infant with uncomplicated midgut malrotation, only signs of duodenal obstruction were present. The findings at US of duodenal obstruction associated with thickened bowel loops to the right of the spine and peritoneal fluid should lead the sonologist to suspect midgut malrotation complicated by volvulus, a potentially fatal condition, and an upper gastrointestinal series should then be performed to confirm the diagnosis.

Duodenal Obstruction↗
PubMed1991

Parotid enlargement in children seropositive for human immunodeficiency virus: imaging findings.

We investigated the clinical, immunologic, and imaging features of parotid enlargement in 10 children seropositive for human immunodeficiency virus (HIV) who were infected prenatally. In seven patients, sonography revealed many small hypoechoic areas suggestive of lymphoid infiltration. In three older children, large anechoic areas suggesting lymphoepithelial cysts were present. The lesions probably represent generalized lymphoid infiltration akin to pulmonary lymphoid hyperplasia, although only two of our patients had radiologic evidence of pulmonary lymphoid hyperplasia. Four of five of the children with parotid enlargement who had immunologic studies were phenotypically HLA-DR5, an immunophenotype associated with improved immune response, occurring in less than one in four in the normal population. This suggests that painless parotid enlargement may be a good prognostic sign in HIV-seropositive children. Parotid enlargement was found in 10 HIV-positive children from 6 months to 11 years old. All except one were infected prenatally.

Antibodies, Viral↗
PubMed1990

A rational approach to the diagnosis of hypertrophic pyloric stenosis: do the results match the claims?

The currently accepted premise that the diagnosis of hypertrophic pyloric stenosis (HPS) should be made on clinical grounds, with ultrasound (US) and upper gastrointestinal series (UGIS) reserved for those with a negative clinical examination, was tested. Variable clinical skills of initial examiners, including pediatric surgeons, made abdominal palpation no more sensitive or specific than US or UGIS. For those with a negative clinical examination, proceeding directly to a UGIS will result in monetary savings, especially if good clinical performance decreases the probability of HPS among those without palpable pyloric "tumors." The benefits of a "US first" approach (no radiation, better patient and parent acceptance, no contrast medium) are less apparent but no less important and increase as clinical experience declines and performance of US improves. Criteria for the clinical or sonographic diagnosis of HPS should be kept strict to avoid false-positive results; false-negatives and other causes of vomiting should be identified by UGIS.

Diagnosis, Differential↗
PubMed1990

Lymphoma of the mediastinum and neck: evaluation with Ga-67 imaging and CT correlation.

The role of gallium-67 in the differentiation between active disease and fibrotic changes in patients with childhood lymphoma involving the mediastinum and neck was evaluated prospectively. Ga-67 imaging and computed tomography (CT) were correlated with clinical findings at the time of initial presentation and follow-up in 19 patients. Both modalities enabled detection of active disease on all occasions, but CT results were false-positive for residual disease in 10 patients (53%), whereas Ga-67 imaging results were false-positive in only one patient (5%). Neither modality, however, proved accurate in patients with rebound thymic hyperplasia. Ga-67 imaging is a useful tool for assessing response to therapy in children with lymphoma of the mediastinum and neck.

Adolescent↗
PubMed1990

Clinical activities of pediatric radiologists in the United States and Canada: 10-year follow-up.

The members of the Society for Pediatric Radiology were surveyed in 1989 about their involvement with newer imaging modalities. Results were compared with those obtained in a similar study performed 10 years earlier. The performance and monitoring of imaging studies increased dramatically, with most respondents now being involved with ultrasound (US) and computed tomography (CT), and almost one-half involved with magnetic resonance (MR) imaging. When equipment became available, pediatric radiologists were quicker to assume control of MR imaging than US and CT. In most large pediatric centers, imaging with all current modalities and of all organ systems has become the responsibility of pediatric radiologists. These findings are in contrast to those obtained in 1979, when pediatric imaging practices primarily consisted of conventional radiography and fluoroscopy.

Canada↗