Heterogeneous splenic enhancement patterns on spiral CT images in children: minimizing misinterpretation

PURPOSE: To (a) determine the appearances and timing of heterogeneous splenic enhancement at spiral computed tomography (CT) and (b) identify variables influencing heterogeneous splenic enhancement. MATERIALS AND METHODS: Sequential isolevel (24-mAs) CT images of the spleen obtained at 6-second intervals after initiation of contrast material injection in 112 children (mean age, 4.5 years) were reviewed. Heterogeneity characteristics assessed included type, onset, maximum, and resolution. Relationship to variables (injection rate, age, splenomegaly) was assessed with the Fisher exact test. RESULTS: Eighty-one of the 112 patients (72%) had transient heterogeneity: archiform (45 patients), diffuse (25 patients), and focal (11 patients). Mean times were as follows: initial visualization after onset of contrast material injection, 19.2 seconds; maximum heterogeneity, 27.3 seconds; and resolution, 47.4 seconds. Statistically significant relationships were seen between frequency of heterogeneity and injection rate (> or = 1 mL/sec, 82%; < 1 mL/sec, 50% [P = .001]), age (> 1 year, 76%; < or = 1 year, 46% [P = .04]), and splenomegaly (present, 20%; absent, 77% [P = .048]). CONCLUSION: Heterogeneous splenic contrast enhancement is common, has several patterns of appearance, and is predictably encountered during the 70 seconds after the initiation of contrast material injection. Injection rate, age, and presence of splenic disease influence the frequency with which these artifacts are encountered.     

Optimizing contrast-enhanced abdominal CT in infants and children using bolus tracking

OBJECTIVE: Manual administration of IV contrast material results in unpredictable injection rates. Our purpose was to determine the effect of bolus tracking on overall abdominal helical CT scan quality, particularly on hepatic enhancement, in children with manually administered contrast media. MATERIALS AND METHODS: We compared 33 abdominal helical CT scans of 29 children in whom bolus tracking was used with 22 CT scans of a control group of 21 children in whom bolus tracking was not used. All contrast material was administered by manual injection. Qualitative assessment was made of organ and vessel enhancement and overall scan appearance. Quantitative assessment using region-of-interest cursors was performed at three anatomic levels, and the results for the two groups of children were compared. RESULTS: Qualitative comparison of enhancement parameters between the bolus tracking group (number given first) and the control group (number given second) yielded the following: splenic artifact in 9% versus 23% (p = .24); inferior vena cava flow artifact in 3% versus 27% (p = .01); scanning during the nephrographic phase in 89% versus 59% (p = .02); and good quality grade in 79% versus 64% (p = .23). Significantly greater hepatic enhancement (as measured in mean Hounsfield units) was achieved in the bolus tracking group than in the control group at the superior (48.5 versus 28.6; p < .001), middle (47.9 versus 32.3; p < .001), and inferior (48.2 versus 36.5; p = .01) levels. Hepatic enhancement increased significantly from the superior to the inferior level in the control group (p < .02), whereas enhancement was homogeneous in the bolus tracking group (p > .50). CONCLUSION: Bolus tracking provides improved contrast enhancement, including significantly greater hepatic enhancement, during abdominal helical CT in children in whom the rate of injection of contrast material is unpredictable.     

Thoracic manifestations of neurofibromatosis-I

The intrathoracic manifestations of neurofibromatosis-I are protean and can, on occasion, mimic those of malignancy. Many of the intrathoracic findings are characteristic of the disease and can be expected to be present. Knowledge of the full spectrum of radiologic findings can thus be useful in preventing diagnostic error. Furthermore, an unexpected finding, such as rapid growth of a neural tumor, should be recognized as an atypical feature (suspicious for malignant degeneration) and result in further evaluation.     

An international outbreak of Vero cytotoxin-producing Escherichia coli O157 infection amongst tourists; a challenge for the European infectious disease surveillance network

In March 1997, an outbreak of Vero cytotoxin-producing Escherichia coli O157 (VTEC) infection occurred amongst holidaymakers returning from Fuerteventura, Canary Islands. For the investigation, a confirmed case was an individual staying in Fuerteventura during March 1997, with either E. coli O157 VTEC isolated in stool, HUS or serological evidence of recent infection; a probable case was an individual with bloody diarrhoea without laboratory confirmation. Local and Europe-wide active case finding was undertaken through national centres, Salm-Net and the European Programme of Intervention Epidemiology, followed by a case-control study. Fourteen confirmed and one probable case were identified from England (7), Finland (5), Wales (1), Sweden (1) and Denmark (1) staying in four hotels. Three of the four hotels were supplied with water from a private well which appeared to be the probable vehicle of transmission. The case-control study showed illness was associated with consumption of raw vegetables (OR 8.4, 95% CI 1-5-48.2) which may have been washed in well water. This investigation shows the importance of international collaboration in the detection and investigation of clusters of enteric infection.     

Marrow regeneration after mechanical depletion

The origin of marrow regeneration after mechanical depletion was reinvestigated in mouse chimeras. The results were compatible with the local origin of stem cells from remnants of incompletely removed marrow, but not with their origin from a common precursor of both bone and hemopoietic cell lines. In transplanted femurs depleted by a modified technique of in vivo evacuation of marrow, hemopoietic regeneration failed to occur. The presence of hemopoietic stem cells in the Haversian canals was thus excluded. The demonstration of ample hemopoiesis with minimal bone formation in nondepleted controls in which bone marrow initially became necrotic provided new evidence that osteogenesis was not a prerequisite of hemopoietic regeneration.     

Limited access trial using amifostine for protection against cisplatin- and three-hour paclitaxel-induced neurotoxicity: a phase II study of the Gynecologic Oncology Group.

PURPOSE: The purpose of this study was to determine whether amifostine (WR-2721) prevents or ameliorates clinically significant (grade 2 to 4) neurotoxicity associated with cisplatin and 3-hour paclitaxel chemotherapy.Materials and METHODS: The chemotherapy program consisted of intravenous paclitaxel 175 mg/m2 over 3 hours followed by amifostine 740 mg/m2 and cisplatin 75 mg/m2 administered over 90 minutes beginning 15 minutes after amifostine administration. At baseline, before each treatment cycle, and for 3 months after completing chemotherapy, patients were evaluated for evidence of neurotoxicity and other treatment-related adverse effects using three methods: standard clinical evaluation (National Cancer Institute common toxicity criteria [CTC] grading), a neurotoxicity questionnaire to assess symptoms and limitations imposed by peripheral neuropathy, and vibration perception threshold (VPT) testing. RESULTS: Four of 27 assessable patients developed grade 2 to 4 neurotoxicity based on clinical assessments and CTC grading. This number of neuropathic events exceeded the predetermined threshold level for a second stage of accrual and the study was closed. CONCLUSION: Amifostine's level of activity in this trial was insufficient to warrant further study in a phase III trial. Based on the receiver operating characteristic analysis, it would appear that VPT measurements are less sensitive to the development of peripheral neuropathy than the neurotoxicity questionnaire. The questionnaire, referred to as the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity, may be used instead of VPT measurements in future studies of chemotherapy-induced peripheral neuropathy.