John C. Leonidas

Thoracic neuroblastoma : what is the best imaging modality for evaluating extent of disease ?

Background. Thoracic neuroblastoma accounts for 15 % of all cases of neuroblastoma. A minority of children with thoracic neuroblastoma will have dumbbell tumors, i. e., intraspinal extension, but only half these patients will have neurologic signs or symptoms. Hypothesis. MR imaging is the single best test to evaluate the extent of thoracic and spinal disease in thoracic neuroblastoma after the diagnosis of a mass is established on plain film. Materials and methods. A retrospective multi-institutional investigation over 7 years of all cases of thoracic neuroblastoma (n = 26) imaged with CT and/or MR were reviewed for detection of the extent of disease. The chest film, nuclear bone scan, and other imaging modalities were also reviewed. The surgical and histologic correlation in each case, as well as the patients staging and outcome, were tabulated. Results. The chest radiograph was 100 % sensitive in suggesting the diagnosis. MR imaging was 100 % sensitive in predicting enlarged lymph nodes, intraspinal extension, and chest wall involvement. CT was 88 % sensitive for intraspinal extension but only 20 % sensitive for lymph node enlargement. CT was 100 % sensitive in detecting chest wall involvement. Direct comparison of CT and MR imaging in six cases revealed no difference in detection of enlarged lymph nodes or chest wall involvement. Neither test was able to detect remote disease, as noted by bone scan. Conclusion. The chest film is 100 % sensitive in suggesting the diagnosis of thoracic neuroblastoma; MR imaging appears to be the single best test for detecting nodal involvement, intraspinal extension, and chest wall involvement.

Adrenocortical carcinoma with extension into inferior vena cava and right atrium: report of 3 cases in children.

We present three cases of adrenocortical carcinoma, a rare tumor in children, with extension into the inferior vena cava and the right atrium. The diagnosis is facilitated by use of ultrasonography, computed tomography and magnetic resonance imaging.

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.

Coincidence-detection FDG-PET versus gallium in children and young adults with newly diagnosed Hodgkin’s disease

Coincidence-detection 18F-FDG-PET (PET) and 67Ga whole-body and SPECT (Ga) were compared in children and young adults with newly diagnosed Hodgkin’s disease (HD). Materials and methods: Thirty patients with histologically confirmed HD underwent PET with attenuation correction 1 h after injection of 150–220xa0MBq 18F-FDG and whole-body and SPECT imaging 72xa0h after injection of 250–370xa0MBq 67Ga citrate. Two experienced readers retrospectively reviewed PET and Ga scans, grading 13 anatomic regions from one (normal) to five (abnormal). Numerical stages were assigned based on Ann Arbor classification. Comparison was made with disease sites (established by biopsy or two or more of the following: physical examination, conventional imaging studies, radionuclide studies, and follow-up studies) and clinical stages. Sensitivity, specificity, and accuracy were calculated and significance of differences determined using McNemar’s test. Results: PET detected 120/138 (87%) disease sites and Ga 109/138 (79%). PET and Ga were concordant for 103/138 (75%) sites. Accuracies were not significantly different for supradiaphragmatic disease. PET was more accurate than Ga for detecting splenic (0.91 vs 0.61, P=0.012), infradiaphragmatic (0.89 vs 0.75, P=0.042), and all disease sites combined (0.95 vs 0.91, P=0.039). PET stage agreed with clinical stage in 79% of patients and Ga in 71%. Conclusion: PET was superior to Ga for evaluating children and young adults with newly diagnosed HD.

Magnetic resonance imaging in acute pyelonephritis

Abstract. The diagnosis of acute pyelonephritis in children remains a clinical challenge. We assessed the feasibility of magnetic resonance imaging (MRI) detection of pyelonephritis in four pediatric patients and compared the results with renal cortical scintigraphy. MRI revealed areas of high signal intensity in the kidney that coincided with photon-deficient regions in the radionuclide scans in two children with acute pyelonephritis. These findings confirm work in experimental animals and indicate that MRI can accurately detect acute pyelonephritis in children.

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

A 3-year-old HIV-positive boy developedPneumocystis carinii pneumonia (PCP) resulting inchronic 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 thatPneumocystis carinii may cause chronic progressive pulmonary fibrosis with cyst formation and respiratory failure.

The thymus: from past misconception to present recognition

Abstract The critical role of the thymus in the development of the immune system was unknown until recently. For a long time physicians were puzzled by the presence of a large thymus in early life and attributed many symptoms to it. This review briefly covers the history of the thymus and its function as a primary lymphoid organ, along with a short background of the development of the immune system. Thymic diseases and their imaging features are also reviewed briefly.

Neuroblastoma Presenting with Myoclonic Encephalopathy

A curious association between myoclonic encephalopathy and neuroblastoma in children has recently been reported with increasing frequency. The authors report a case in which knowledge of this association led to early detection of a silent intrathoracic neuroblastoma. An occult malignant neural crest tumor should be suspected in any child presenting with myoclonic encephalopathy.

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.

Aneurysm of the vein of Galen: ultrasound, MRI and angiographic correlations

We report a case of a vein of Galen Aneurysm in a neonate in which MR imaging provided precise anatomic information, including feeding and draining vessels. MRI may become the most definitive imaging procedure in vein of Galen malformations.