Potential pitfalls in nuclear medicine: a paediatric teaching case.

An infant with complex cardiac defects and isomerism had a persistent pyrexia of undetermined aetiology following cardiac surgery. Radionuclide leucocyte scan showed a focus of increased uptake in the right upper quadrant (RUQ) felt to be compatible with an abscess. However, correlation with clinical data and multimodality imaging allowed the correct diagnosis of ectopic splenic tissue in the RUQ to be made. This report emphasises the need for an integrated approach to imaging. Patients with abnormalities of viscero-atrial situs require careful assessment of their splenic status. Visceral heterotaxy may result in confusing imaging appearances unless the anatomy has been accurately documented.

Guided versus blind liver biopsy for chronic hepatitis C: clinical benefits and costs.

BACKGROUND/AIMS: Our objectives were: (1) to assess the clinical benefits and costs of performing ultrasound-guided liver biopsy with an automated needle compared to blind biopsy with a conventional Trucut needle in patients with chronic hepatitis C; (2) to compare the histological yield of automated needles with Trucut needles. METHODS: We prospectively studied 166 patients with hepatitis C virus who underwent either ultrasound-guided biopsy using automated ASAP needles or blind biopsy using conventional Trucut needles. Both groups were matched for age, sex, cirrhosis, needle gauge and operator experience. Patient tolerance, complications and histological adequacy were assessed. In a separate in vitro study, we assessed the histological adequacy of liver biopsy specimens obtained using automated and Trucut needles from 10 fresh autopsy cases. RESULTS: Ultrasound-guided biopsy caused significantly less biopsy pain (36.4% vs. 47.3%; p < 0.0001) and significantly less pain-related morbidity (1.8% vs. 7.7%, p < 0.05). Although, there was no significant difference in diagnostic yield between guided and blind biopsy (98% vs. 94%, p = 0.15), 3 blind biopsies (3.3%), including 2 which yielded extra-hepatic tissue, had to be repeated. The additional expense of performing guided liver biopsy with automated needles was 42 Irish Pounds per patient. In vitro, automated ASAP 15G needles provided liver specimens comparable to Trucut 15G needles and had the highest histopathologic score among the automated needles assessed. CONCLUSIONS: Even in the absence of major complications, ultrasound-guided liver biopsy with an automated needle in HCV patients is safer, more comfortable and only marginally more expensive than blind Trucut biopsy.

Dose reduction in double contrast barium enema by use of low fluoroscopic current.

Under standard conditions double contrast barium enema (DCBE) was carried out on a selected patient cohort using either standard (1.5 mA) or low (0.5 mA) fluoroscopic current. A statistically significant (p < or = 0.01) reduction in total dose was achieved by use of low screening current. This reduction was of the order of 40%. Fluoroscopic image quality was analysed both objectively and subjectively, and was found not to be significantly degraded when the lower current was used. On blinded evaluation all examinations were found to be of diagnostic quality. The use of low fluoroscopic current results in a reduction in patient dose, without compromising fluoroscopic image quality or diagnostic standard of the examination. Low fluoroscopic current technique has been adopted as the standard in our department.

The central-peripheral transitional regions of cranial nerves. Oculomotor nerve.

Oculomotor nerve rootlets varied more markedly in size and in transitional zone length and form than those of any other nerve studied to date. However, they could be classified into four main types, each of which was associated with a characteristic type of central-peripheral transitional zone. Type 1 rootlets emerged from the brainstem through a tongue-shaped elevation of the glia limitans. This type of central-peripheral transition is found elsewhere only in a minority of abducent rootlets (Fraher et al. 1988). Type 2 rootlets contained long segments made up entirely of central nervous tissue and were the only motor rootlets so far described to contain a segment of this kind. Type 3 rootlets were the commonest and the largest. Before leaving the brainstem they ran laterally on its surface as the emergent rootlet segments, forming plexuses with one another. These rootlets contained a unique wedge-shaped type of central tissue projection. Over its entire length one surface of this coincided with the rootlet surface and a thin tapering strip of peripheral nervous tissue extended proximally for a considerable distance into the emergent rootlet segment. Type 4 rootlets emerged from the brainstem surface obliquely and contained a glial fringe.

The central-peripheral transitional regions of cranial nerves. Trochlear and abducent nerves.

Unlike all other nerves containing somatic efferent fibres, the trochlear nerve emerges from the dorsal aspect of the brainstem. It generally emerges as a single trunk which resembles a dorsal rather than a ventral spinal nerve rootlet in terms of its size and of the morphology and position of the central tissue projection which it contains. The morphology of the central-peripheral transition of the trochlear nerve is therefore correlated with its dorsal location rather than with the nature of its constituent fibres. By contrast, abducent nerve rootlets emerge from the ventral aspect of the neuraxis, in line with other cranial and with spinal ventral nerve rootlets which also contain somatic efferent fibres. Its rootlets resemble the latter in terms of their size, being much smaller than those of dorsal rootlets or the trochlear nerve. They possess two distinct types of central-peripheral transitional zone: those of the rostral rootlets resemble zones of cervical ventral spinal rootlets. Many of these emerge through a circumscribed thickening of the astrocytic glia limitans. Caudal abducent rootlets emerge through a tongue-shaped glial elevation projecting above the level of the surrounding brainstem surface, resembling Type 1 oculomotor rootlets.