Sedation/anaesthesia in paediatric radiology.

OBJECTIVES: In this article we will give a comprehensive literature review on sedation/general anaesthesia (S/GA) and discuss the international variations in practice and options available for S/GA for imaging children. METHODS: The key articles were obtained primarily from PubMed, MEDLINE, ERIC, NHS Evidence and The Cochrane Library. RESULTS: Recently, paediatric radiology has seen a surge of diagnostic and therapeutic procedures, some of which require children to be still and compliant for up to 1 h. It is difficult and sometimes even impossible to obtain quick and high-quality images without employing sedating techniques in certain children. As with any medical procedure, S/GA in radiological practice is not without risks and can have potentially disastrous consequences if mismanaged. In order to reduce any complications and practice safety in radiological units, it is imperative to carry out pre-sedation assessments of children, obtain parental/guardian consent, monitor them closely before, during and after the procedure and have adequate equipment, a safe environment and a well-trained personnel. CONCLUSION: Although the S/GA techniques, sedative drugs and personnel involved vary from country to country, the ultimate goal of S/GA in radiology remains the same; namely, to provide safety and comfort for the patients. Advances in knowledge Imaging children under general anaesthesia is becoming routine and preferred by operators because it ensures patient conformity and provides a more controlled environment.

Case report: Solitary plasmacytoma of bone with oncogenic osteomalacia: recurrence of tumour confirmed by PET/CT. A case report with a review of the radiological literature.

We describe a case of oncogenic osteomalacia secondary to solitary plasmacytoma of the vertebral body of T3. The patient presented with symptoms of hypophosphataemia. Following the initial diagnosis, the lesion was surgically resected with good results, although several follow-up procedures, including bone grafting, were necessary to stabilize the thoracic spine. The lesion recurred almost 15 years after its initial resection, again presenting with hypophosphataemia and neurological symptoms suggestive of local tumour recurrence. A variety of radiological examinations were performed in an attempt to confirm and localize recurrent tumour, including bone scintigraphy, (111)indium octreotide scintigraphy, high-resolution CT and MRI of the thoracic spine, but these yielded only negative or equivocal results owing, in part, to the presence of extensive post-operative changes, and also to a difference in the MR signals of the recurrent and original tumours. Positron emission tomography (PET/CT) demonstrated a solitary focus of intense fluorodeoxyglucose uptake in the T3 vertebral body, enabling a definitive diagnosis of recurrent plasmacytoma. This case illustrates the diagnostic value of PET/CT in the setting of challenging post-operative changes in the surrounding tissue and in the appearance of the tumour itself. Relevant related imaging literature is also reviewed.

Elastography in the detection of prostatic cancer.

We describe a simple, practical technique for producing elastography images of the prostate. Our standard technique for the detection of prostatic cancer is ultrasound guided systematic biopsy of the prostate, with extra targeted biopsies of any abnormal areas detected by grey-scale ultrasound. The aim of this study to determine whether adding elastography imaging with targeted biopsies of abnormal areas detects more cancers. The results of elastography imaging were evaluated against grey-scale images and biopsy data in 100 patients. Elastography detected an additional 5 cancers in the 100 patients and detected an extra 3 patients with cancer at the expense of 8 extra biopsies. This represents a significant improvement in the detection rate of prostatic cancer.

Imaging features of primary malignant rhabdoid tumour of the brain.

Primary malignant rhabdoid tumour of the central nervous system is a rare neoplasm affecting children. We present a pathologically proven case, which was initially referred to the paediatric surgeons as a sebaceous cyst, and highlights the importance of imaging prior to surgery of potentially innocuous scalp lesions. Imaging features on CT and MRI are presented, which show bony involvement not previously reported in the literature.

Optimization of nuclear medicine procedures for the diagnosis and management of thyroid disorders: report of a research coordination meeting held in Vienna, 15-17 December 1986 under the auspices of the International Atomic Energy Agency.

The third and final meeting of a coordinated research programme on the diagnosis and management of thyroid disorders was held in Vienna from 15 to 17 December 1986. The participants were from Czechoslovakia, Egypt, Israel, Malaysia and Thailand. Each participant had studied between 500 and 1000 patients for thyroid function evaluation by performing T3, T4 and TSH radioimmunoassays. Each had also used the newly available supersensitive immunoradiometric (IRMA) assay in a group of patients to compare the efficiency of the new assay with that of the conventional assay. A microcomputer was provided to each participant for data analysis. Internal quality control was studied by establishing precision profiles and external quality control was on the basis of pooled standard sera in different ranges. Recommendation for the strategy suggested T4 RIA as the test of first choice in each category of thyroid function. IRMA TSH was suggested as a second test in borderline cases.

Thyroid function and thyrotropin levels in rabbits immunized to produce antibodies against thyroid hormones.

Various parameters of thyroid function were studied in 27 rabbits, out of which 10 were immunized to produce antibodies against triiodothyronine (T3), 9 against thyroxine (T4) and 8 were normals. Estimations of T3, T4, Free T4 (FT4) and thyrotropin (TSH) in blood, qualitative and quantitative analysis of iodoamino acids in serum, protein bound iodine-131 (PB131I), butanol extractable iodine-125 (BE125I) and measurement of the disappearance rates of 125I-labelled T3 and T4 from plasma were done. In addition, glandular changes were also studied by measurement of 131I uptake, thyroid scanning and chromatographic analysis of hydrolysate of soluble iodoproteins. In T3 immunized animals, levels of T3 in serum increased by 38 to 125 times, levels of TSH also showed a significant rise (7.4 +/- 1.2 vs 28 +/- 9 ng/mL). Chromatographic analysis of iodoamino acids in serum as well as in the hydrolysate of the thyroid gland demonstrated a selective increase in synthesis of T3. Rate of disappearance of T3 from blood showed a significant decline. Thyroid glands in the immunized rabbits showed signs of hypertrophy and hyperplasia. Identical studies done in rabbits immunized to produce antibodies against T4 showed a similar pattern though of variable degree. Our studies indicate that the thyroid glands of the immunized rabbits undergo marked alterations resulting in selective increase in the synthesis and secretion of the particular thyroid hormone against which they were immunized. They do so under the influence of increased levels of TSH.

Increased sensitivity of triiodothyronine antibodies for radioimmunoassay after removal of endogenous antigen by simple laboratory procedures.

Conventionally produced antibodies against triiodothyronine (T3) are known to possess high amounts of endogenously produced T3 associated with them. We felt that such antibodies would work better for T3 radioimmunoassay (RIA) after prior removal of the antigen. With this in view, we attempted dissociation and subsequent removal of T3 from antisera by two different methods, viz. dialysis and alcohol extraction. It was possible to remove T3 to an extent of 77% by alcohol extraction and 60% by dialysis. Resultant antisera fail to demonstrate any increase in the titre. However, when standard curves were generated using these antisera, the assays became more sensitive and it was possible to detect T3 in concentrations as low as 6.25 pg. The affinity constants of these antisera calculated from the respective Scatchard plots were found to have increased after both dialysis treatment was well as alcohol extraction. This was thought to be due to rendering some of the high affinity binding sites on the antibodies free of antigen after treatment. Serum T3 levels were measured in 68 patients with various thyroid status using both treated as well as untreated antiserum. The difference between the average values of serum T3 concentration estimated using various antisera before and after the treatment was not statistically significant. Our results suggested that a simple procedure like stripping of antigen from antibodies could be of help for acquiring high affinity and high sensitivity antibodies for this purpose.

Influence of initial large dose on subsequent uptake of therapeutic radioiodine in thyroid cancer patients.

Fifty-two patients with differentiated thyroid cancer, following thyroidectomy were studied by administering a quantity of up to 5 mCi of [131I]sodium iodide. In most of these patients, radioiodine uptake values obtained with the subsequent therapeutic dose were markedly lower than those observed with the initial doses. This observation was verified in seven of the patients with differentiated thyroid cancer, by measuring the radioiodine uptake with a second dose of 4.5 mCi of [131I]sodium iodide. Calculations showed that the major etiology was probably therapeutic irradiation of the thyroid by the first dose.

Modified rapid radiometric method for detection of Mycobacterium tuberculosis from sputum samples.

A modified, simple and radiometric method for early detection of M. tuberculosis from sputum samples has been developed using a biphasic vial system for detection of 14C-CO2 produced by the metabolism of 14C-U-acetate on glycerol-free Lowenstein-Jensen medium (LJM). Of the 84 smear positive sputum samples examined, 85.7% and 86.9% were scored positive by radiometric and visual methods respectively. The detection rates at 1st, 2nd and 3rd week of the test were 53.3%, 60.7% and 82.1% by radiometry and 1.2%, 11.9% and 54.8% by visual methods respectively. The mean detection time was 10.7 days by the radiometric and 21.0 days by the visual method. An average replication time of primary culture from 54 sputum samples was 25.58 +/- 6.92 h (range 10.0-39.1 h).

Significance of circulating immune complexes in pulmonary tuberculosis.

In the present study we have tried to demonstrate circulating immune complexes (CIC) in sera from patients with pulmonary tuberculosis (TB) by three techniques; latex agglutination; 3.5% PEG precipitation and determination of optical density at 280 nm and RIA of CIC using bovine spermatozoa. About 40 normal control sera and 100 TB patients sera were investigated for the presence of CIC. Seventeen per cent cases of pulmonary TB were positive by latex agglutination while none of the control was positive. Levels of CIC as detected by PEG precipitation and RIA were significantly elevated in patients as compared to normal controls. While IgG, IgA and IgM were elevated in the CIC of patients, IgM immunoglobulins were detected only in patients and not in controls. Detection of CIC may at times be useful in diagnosis, prognosis and therapeutic monitoring of disease processes, but it is the characterization of immune complexes (IC) and identification of the specific components of these complexes which holds the greatest potential for better understanding of disease mechanisms. CIC were precipitated using 3.5% PEG from sera of patients suffering from TB. The specific anti-TB antibody component of complex was determined using S. aureus protein A as a solid phase, Anti-BCG antibody and 125I-labelled TB antigen. The specific TB antigen component of the IC was dissociated thermally from TB antibody and assayed by a radioimmunoassay technique developed in our laboratory. Patients were classified into two groups. Those those sputum was positive for Mycobacterium tuberculosis by smear and/or culture and those whose sputum was negative. The TB antigen concentrations of CIC was higher 19.1 +/- 2.3 ng/ml (mean +s.e.) in sputum positive cases, and 9.9 +/- 1.9 ng/ml in sputum negative cases as compared to 2.2 +/- 0.3 ng/ml in controls. Patient groups were significantly different from controls as well as from each other (P less than 0.001). Anti-TB antibody ratios were 11.7 +/- 1.48, 5.1 +/- 1.5 and 0.6 +/- 0.1 in sputum positive, sputum negative and controls. The significance of differences between the groups was P less than 0.001. The effect of treatment administered over a period of 12 weeks or more was evaluated. It was observed that in patients with persistent demonstration of M. tuberculosis in the sputum, the TB antigen and TB antibody levels of CIC were consistently high. In patients who responded to anti-tubercular drugs the TB antigen levels decreased progressively while TB antibody levels remained high.(ABSTRACT TRUNCATED AT 400 WORDS)

Synthesis of thyroglobulin in thyroid carcinoma patients after radioiodine therapy.

Endogenously radioiodinated thyroglobulin (Tg) and the serum concentration of Tg have been measured in patients with metastatic thyroid carcinoma after therapeutic doses of radioiodine. Serial samples of blood were analyzed for both these parameters over a period of 10 to 22 days. The specific activity of Tg (cpm/ng) was calculated for each sample. Among the six patients studied, three showed constant specific activity. The specific activity of the other three fell, indicating the entering of newly synthesized Tg into the circulation. The respective amounts of Tg entering into the circulation in these three patients were 120, 852, and 20,935 ng/ml serum/day.