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Le malformazioni caratterizzate da divisione del midollo spinale (“Split cord malformation”) sono rare forme di disrafismo spinale occulto che si sviluppano precocemente nel corso della vita embrionale. I pazienti che ne sono affetti presentano elevati rischi di sviluppare deficit neurologici gravemente invalidanti nel corso della vita, per l'ancoraggio midollare sempre presente. Già alla nascita, la maggior parte di essi presenta anomalie cutanee (ipertricosi, nevi, angiomi, fossette o fistole e lipomi sottocutanei) localizzate generalmente in regione lombo-sacrale che costituiscono spesso l'unico segno della sottostante patologia. Descriviamo gli aspetti neuroradiologici e neurochirurgici di un raro caso di divisione midollare associata a tehered cord, doppio seno dermico ed anomalie vertebrali multiple. Neonata da parto spontaneo alla 38° settimana con peso alla nascita di g. 3100 e Apgar 8/10, che presenta stigmate disrafiche cutanee ed una modesta iperreflessia rotulea bilaterale con lieve ipotonia degli arti inferiori. Al 2° giorno di vita viene effettuato studio neuroradiologico encefalo-spinale con Risonanza Magnetica (RM), Tomografia Computerizzata (TC) ed ecografia che mette in evidenza la presenza di una doppia corda midollare con unico rivestimento durale (tipo II di Pang), un duplice seno dermico, a L3-L4 ed a livello coccigeo con ancoraggio midollare ed alcune anomalie vertebrali (vertebra a farfalla a T12 e schisi multiple). A 22 giorni dalla nascita la piccola paziente è stata sottoposta con successo ad intervento chirurgico per disancoraggio del midollo. I reperti operatori hanno confermato l'ipotesi diagnostica neuroradiologica. Nel corso dei mesi successivi sono stati eseguiti controlli clinici e strumentali seriati, compresa una valutazione urodinamica, che non hanno mostrato deficit neurologici o sfinterici. A distanza di un anno la piccola presenta un regolare sviluppo psicomotorio ed è neurologicamente indenne. I disrafismi spinali, comprendono spesso malformazioni complesse che sebbene rari esistono e necessitano di una diagnosi precoce e di un trattamento rapido, prima dell'insorgenza di deficit neurologici gravi ed irreversibili. Le anomalie cutanee rappresentano spesso l'unico segno della malformazione, in particolare nei neonati, nei quali i segni clinici sono assenti o difficilmente valutabili. La diagnostica neuroradiologica (RM in particolare) è del tutto affidabile nell'individuare le cause che determinano l'ancoraggio midollare al fine di favorire un trattamento neurochirurgico efficace, come confermato anche in questa nostra esperienza.

Abstract.: Nodular hepatocellular carcinoma (HCC) is characterized by the presence of a pseudocapsule (constructed usually from connective fibrous tissue) that appears hypointense on T1- and T2-weighted spin-echo (SE) and gradient-echo (GE) MR imaging sequences without a contrast medium. The presence of vascular structures inside the tumor, which are verified by histological exam, affects enhancement of the PC after administrating the contrast medium: The impregnation is more evident in the dynamic study but also persists on the delayed T1-weighted SE images. The accuracy of MR in detecting the pseudocapsule of HCC and contrast enhancement of the pseudocapsule during dynamic studies were evaluated and related to pathological findings. Thirty-seven HCC were examined in 33 patients and afterwards resected. In capsulated nodules, besides usual hematoxylin, eosin, and trichrome stainings, histochemical and immunohistochemical methods were performed. On a 1.5-T MR unit, T1- and T2-weighted SE and GE FLASH 2D sequences after intravenous injection of Gd-DTPA (dynamic study) were used. In a later phase, T1-weighted SE sequences were repeated. Histologically, the pseudocapsule (thickness 0.2–6 mm) was present in 26 of 37 nodules (70 %). The dynamic study was the most suitable technique to show the pseudocapsule, which was recognized in 80.7 % (21 of 26 nodules). In 5 of 26 cases, the pseudocapsule, not demonstrated by MR, was thinner than 0.4 mm. In 16 of 21 cases, in the early portal phase (30–60 s), the pseudocapsule had an early enhancement, which was more evident later; in 5 of 21 cases the enhancement was observed only in the late portal phase (1–2 min). At histological examination, 14 of 16 pseudocapsules with early enhancement showed a more prominent vasculature than those with enhancement in the equilibrium phase. Magnetic resonance was a reliable tool in demonstrating the pseudocapsule of HCC. The histological examination demonstrated a good correlation between the enhancement behavior and the vessel number of the pseudocapsule.

In order to compare the advantages and failings of the current imaging procedures used for the staging of parotid masses, 121 patients were investigated: 30 with ultrasound (US) and CT, 55 with US and MRI, and 36 with US, CT and MRI. The accuracy of the three imaging modalities was evaluated in detecting parotid lesions; in assessing their location (intra- or extraglandular) and nature (benign or malignant); and in defining their intraglandular extent (superficial or deep lobe) as well as their relationship with surrounding structures. The imaging findings were related to the cytohistological data from US-guided biopsy or from surgical resection. In the 36 patients studied with all three modalities the diagnostic accuracy (excluding double errors in the same patient) was 77.7% for US, 86.1% for CT and 94.4% for MRI. US was thus shown to be less accurate than CT or MRI, and MRI not significantly superior to CT. US with fine-needle aspiration cytology should be the first-line imaging technique; CT and MRI have to be- considered for lesions more than 3 cm in diameter or for masses arising in the deep lobe of the gland. The results of this series show that MRI provides better results than CT in displaying the relationship of the mass with contiguous structures.

This paper describes an approach to library instruction in psychology, involving analysis of the natural structure of the research literature. An example using Festinger's theory of cognitive dissonance is presented. This approach is suggested for use as a complement or alternative to the search strategy method of instruction.

Moderate-sized academic libraries in the United States were surveyed to determine current practices in the housing of periodical indexes and abstracts. Additionally, information was gathered on how librarians expedited public use of these reference resources. It is suggested environmental factors exist that effect the efficiency of information retrieval through indexes and abstracts.