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Over Christmas 1993, an outbreak of food poisoning occurred among guests in a hotel in South West Scotland. Evidence from a cohort study strongly suggested that raw oysters were the vehicle for infection, probably due to a Small Round Structured Virus (SRSV). Detailed enquiry about the source and preparation of the oysters revealed no evidence of any unsafe handling at any stage in the food chain, nor any evidence of bacterial contamination. It is suggested that the present standards of preparation and monitoring are inadequate to protect the consumer, and that bacteriophage monitoring may be a useful method of screening for viral contamination in future.

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Cerebral magnetic resonance imaging (MRI) was performed on 18 patients with migraine characterized by aura consisting of both visual symptoms and paresthesias. Fifteen headache-free individuals of the same age range were used as controls. Records were randomized and read in blind fashion by two neuroradiologists. Small subcortical white matter lesions were seen in three migraine cases and two controls. In one migraine case cortical infarctions were seen. In two controls, small areas of increased density similar to those in migraine were seen. No consistent correlation of migraine or its duration with cerebral atrophy was found. It is concluded that identification of both these MRI findings (small subcortical white lesions and cerebral atrophy) as significantly associated with migraine is doubtful.

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The hardcopy recording technologies of video cameras, slow-scan (digital spot) recorders, and laser film printers are presented and compared. Slow-scan (digital spot) recorders offer a few advantages when compared with multiformat video cameras. But only laser film printers provide the high-quality hardcopy recordings and speed required by newer digital imaging modalities.

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We have used an intracranial 9L rat brain tumor model to determine whether a novel metalloporphyrin, Mn[III] uroporphyrin I (MnUROP-I), could function as an intravenous MRI contrast agent for brain tumors. In several experiments, 24 male Fischer 344 rats were inoculated intracranially with 9L brain tumor cells. On day 15 postinoculation, animals were anesthetized and the femoral vein exposed. Prior to the intravenous injection of the contrast agent, a precontrast scan (1 Tesla in a standard head coil) was performed. Thirty min after injection of the contrast agent, a postcontrast scan was performed. Although there was only a suggestion of abnormality on the precontrast scans, the presence of tumor was visibility enhanced in the postcontrast scans. In 3 animals scanned at 24 hr postinjection, persistent tumor enhancement was demonstrated. Measured tumor sizes on the MRI scans were consistent with sizes measured at autopsy and histologically. These results demonstrate that MnUROP-I is an effective MRI contrast agent for the detection of an intracranial brain tumor in the rat model.

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A teleradiology system acquires radiographic images at one location and transmits them to one or more remote sites, where they are displayed and/or converted to hard copy. These systems often employ wide area networks. Their goal is to provide improved radiologic services at all sites on the network. Experience in the use of teleradiology systems has demonstrated the need for a laser film digitizer, an optical disk, and a high-quality display and/or laser film printer at each site. Single-site hardware purchase costs average $196,000, plus an additional 20% for yearly network services. Hardware purchased for a consultation or central referral facility approximates $344,000.

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This study was performed to compare the performances of observers using three display formats for chest radiography. The display formats were conventional radiographs, digitized radiographs (2,048 X 2,048 X 12 bits) printed on laser film, and digitized radiographs (2,048 X 2,048 X 12 bits) displayed on a high-resolution (2,560 X 2,048 X 12-bit) gray-scale display. The test set for the study consisted of 163 cases. Sixty-four of the cases were normal, whereas the 99 remaining cases demonstrated one or more common radiographic abnormalities. Nine abnormalities were selected for analysis: costophrenic angle blunting, interstitial disease, atelectasis, pneumothorax, parenchymal mass, consolidation, obstructive disease, hilar/mediastinal mass, and apical scarring. Six experienced general radiologists participated in the evaluation. Receiver operating characteristic curves were generated for each abnormality and display format. The results indicate that, while the three display formats are equivalent for the detection of some abnormalities, detectable differences in observer performance may be seen even at 2,048 X 2,048 X 12 bits for the detection of obstructive disease, pneumothorax, interstitial disease, and parenchymal masses.

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We conducted a preliminary evaluation of a digital fluoroscopy system for general applications, including gastrointestinal imaging, venography, myelography, and genitourinary fluoroscopy. We describe the system, present examples of images obtained in a variety of applications, and assess the performance of the system.

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Photostimulable phosphor radiographic (computed radiographic) systems are being installed and evaluated by radiology departments. The use of interactive image-processing workstations are a major advantage for any computed radiography system. An interactive image-processing workstation enables rapid image retrieval, reduces the examination repeat rate, provides for image enhancement, and rapidly sets the desired display parameters for laser-printed images. The authors have conducted over 2,500 radiographic examinations using a computed radiographic system equipped with an interactive image-processing workstation. Their experience supports the necessity of such a workstation.

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Herpes simplex encephalitis (HSE) is the most common form of sporadic encephalitis in man and usually results in death or permanent neurologic deficit. Neonatal HSE does not show the characteristic anatomic localization in the temporal lobe observed in adults and in older children which suggests that the disease process is different in this age group. The abnormalities observed with radionuclide brain imaging and computed tomography (CT) are more diffuse and bilateral. The clinical outcome of the disease is highly dependent on early institution of therapy. Therefore, early diagnosis is critical. Knowledge of neonatal HSE imaging patterns may alert the clinician to the proper diagnosis.

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One of the most effective treatment modalities for tumors of the head and neck has been radiation therapy. In a small number of cases, delayed radiation necrosis of the brain is a dreaded and devastating complication of radiation therapy. The imaging studies (radionuclide brain scan, cerebral angiography, computed tomography and magnetic resonance imaging) in 12 cases of histologically proven, delayed radiation necrosis of the brain are analysed. While both computed tomography and magnetic resonance imaging can depict radiation necrosis with great sensitivity, however, the ability of these imaging techniques to differentiate between radiation necrosis and recurrent or residual brain tumor is low.

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Three cases are presented in which hepatobiliary scans demonstrated extent and course of active bile extravasation. Correlation with computed tomography is demonstrated. The results of the examinations significantly influenced the direction of clinical care of all three patients. Hepatobiliary scanning is suggested for early evaluation of postoperative and post-traumatic complications involving the biliary system.

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Abdominal computed tomography (CT) and other studies were evaluated retrospectively in 46 patients with metastatic adenocarcinoma or undifferentiated carcinoma in whom the primary tumor site was not evident from the history, physical examination, or chest radiograph. The primary site was ultimately located in 21 patients (45.7%). CT of the abdomen in particular detected it in 16 patients (34.8%) and demonstrated additional and often unsuspected metastatic disease in 65%. CT proved superior to sonography in both diagnosis and assessment of the extent of disease and had a significantly higher diagnostic yield than contrast studies of the urinary and gastrointestinal tracts. abdominal CT is recommended as the initial modality in patients with metastatic adenocarcinoma of unknown primary origin. If the abdominal scan is negative, it should be followed by pelvic sonography or CT, particularly in women. Contrast studies should be limited to patients with specific organic dysfunction.

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In this article the results of a pilot project (carried out at King George V Hospital, Durban, and later extended to include all Natal Provincial Administration hospitals) offering free sterilization to persons who attend family planning clinics are reported. A mini laparotomy technique which requires little operative skill, minimizes operative trauma and requires only 24 hours postoperative hospitalization is described.

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During the past 4 years, 16 patients have been seen who developed a unilateral tubo-ovarian abscess while wearing, or soon after removal of, an IUD. None of the patients had gonorrhea. There appears to be a prodromal syndrome before abscess formation of 2 to 5 weeks during which the patient complains of vague lower abdominal pain, pelvic tenderness, and dyspareunia. A few patients had a rapid onset of symptoms. The device should be removed when prodromal symptoms arise and the patient should be treated with antibiotics. Should a tubo-ovarian abscess develop, surgical intervention is necessary.

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