Agreement between emergency physician diagnosis and radiologist reports in patients discharged from an emergency department with community-acquired pneumonia

To evaluate the level of concurrence between radiologist reports and the diagnosis of community-acquired pneumonia (CAP) in patients discharged from an emergency department (ED), a retrospective chart audit of patients discharged with a diagnosis of pneumonia or possible pneumonia from the ED during a 2-year period was conducted. Emergency physician (EP) and radiology report (RR) diagnoses were categorized as pneumonia, possible pneumonia, non-pneumonia and normal, and categories from each were compared. 815 charts were analyzed. Of 671 EP diagnoses of pneumonia, 304 (45.3%) RRs reported pneumonia and 82 (12.2%), possible pneumonia. Of 815 EP diagnoses of pneumonia or possible pneumonia, 426 (52.3%) RRs were in agreement, while 216(26.5%) were of diagnoses other than pneumonia and 173 (21.1%) were read as normal. EPs and radiologists frequently disagree on whether a patient has pneumonia or not. Perhaps it is time to revisit the gold standard status of plain chest X-ray.Presented at the 9th International Conference of Emergency Medicine, Edinburgh, Scotland, 17–21 June, 2002.     

‘Hot’ and ‘cold’ lesions detected by gallium-67 scintigraphy in a pyogenic liver abscess

Most pyogenic liver abscesses appear to be not in a ⁶⁷Ga-citrate study; rarely, a warm or cold area may also be seen. We present a patient with a pyogenic liver abscess that had both cold and hot areas in the ⁶⁷Ga-citrate study. This striking finding is probably related to the different stages of evolution of the abscess.     

The value of bone imaging in multiple myeloma

In a series of 20 patients with a proven diagnosis of myeloma, both full radiographic skeletal surveys and full ratio-nuclide bone images were performed. When these were compared, they showed that (i) imaging underestimated the number of areas involved by 50%, but there were no false negative whole images when compared with the radiology, (ii) large lytic areas on X-ray show as cold areas on the bone image but small ones show as normal, (iii) images that show areas of increased uptake (hot) are almost always associated with fracture, and (iv) patients with bone pain very commonly had hot images corresponding to the region of pain.4th year medical student     

The evaluation of occipital lobe atrophy by computerized tomography before consideration of vertebral artery reconstructive surgery

Summary Occipital lobe atrophy can be identified on CT. In a review of 90 selected cases with brain ischemia symptoms, 45 cases were found to have hindbrain ischemia with symptoms of vertigo and/or blurred vision. Ten cases (22%) had normal CT studies and 35 cases (78%) had abnormal CT studies. The CT brain scan of the cerebellum and occipital lobes has a place in determining whether a patient with clinical hindbrain ischemia is a candidate for angiography and vertebral artery bypass surgery.     

Unexpected differences in early thyroidal trapping of iodide and pertechnetate

Compartmental analysis was applied to simultaneously acquired ¹³²I-iodide and ^99mTc-pertechnetate thyroid uptake data. The method allowed for arterio/venous differences in plasma tracer level and for an instantaneous phase of thyroid uptake.Observations in four thyrotoxic patients, before and during antithyroid drug therapy, revealed greater instantaneous uptake of TcO ₄ ^- . The results also revealed that instantaneous uptake of both I^– and TcO ₄ ^– may increase over the first six months of drug therapy. These findings could not be explained by the estimates of unidirectional clearance which were greater for I^- and varied little during the early stages of drug therapy.     

A nationwide system for computer recording of neuroradiologic examinations

Summary For 2 years the system of recording radiologic examinations connected with the computer called SYBAR has been in operation. The examination methods are coded using the Index of Roentgen Examinations of the Swedish National Medical Board (1970), while the diagnoses are coded according to [4]. The positive experience accumulated so far prompted the authors to project and put in operation the system NEUROSYBAR in order to organize a bank of data of neuroradiologic examinations. This system required the widening of two anatomic fields, skull and contents and spine and contents, according to the Index for Roentgen Diagnoses of the American College of Radiology [1]. The NEURO-SYBAR system was adopted by ten radiologic departments in the country. The complete neuroradiologic data from these departments were collected in one computer center in Lodz.     

Current radiodiagnostic concept of ankylosing spondylitis

Nine radiodiagnostic rules are drawn from the X-rays of 2125 ankylosing spondylitis patients. The significance of early diagnosis of the multicolored sacroiliac X-ray is looked onto; the syndesmophyte, squaring-phenomenon, barrel-shaped vertebra, Romanus and Andersson lesions, and the ossification of ligaments are discussed. The changes at the apophyseal and the costovertebral joints, unimportant for early diagnosis, are explored.     

Disco-vertebral destructive lesions (So-called Andersson Lesions) associated with ankylosing spondylitis

Radiological examination of 31 patients with established ankylosing spondylitis revealed 58 disco-vertebral destructive lesions. Careful assessment of their radiological features permitted differentiation into two main types, (1) inflammatory and (2) non-inflammatory. The inflammatory type may represent either an active inflammatory process or a late sequel to such a lesion. In this series 44 lesions were included in this category, with a marked predilection for the lumbar spine. Moreover, all were observed within the first decade following the onset of the disease.The non-inflammatory type reflects an attempt of a stress fracture in the diseased spinal column to repair by connective tissue, causing a pseudoarthrosis. Eleven such lesions were obseved in this series all occurring more than 12 years after the onset of the disease. In a much smaller group of three cases-here termed the ambivalent type — differentiation between the inflammatory and non-inflammatory types could not be established on radiological grounds alone. It is of interest that all three cases occurred within the first year after the onset of the disease.It is suggested that the term Andersson lesion should be used to include all disco-vertebral destructive lesions related to ankylosing spondylitis—be they of inflammatory or non-inflammatory pathogenesis —as the better known term Romanus lesion includes all types of circumscribed marginal destructive lesions of vertebral bodies without involvement of the disc in ankylosing spondylitis.     

A pattern of post-traumatic demineralization of bone simulating permeative neoplastic replacement: A potential source of misinterpretation

Long bones with a prominent endosteal trabecular pattern, particularly the herringbone configuration, when immobilized, will demineralize in a striking spotty pattern which may simulate neoplastic permeative replacement of bone. The recognition of this phenomenon will obviate needless concern and investigation.     

An unusual bone change in acromegaly

A case of acromegaly is reported showing a layer of bone capping the humeral and femoral heads apparently as the result of new bone formation by the articular cartilage.     

Scintigraphic visualisation of Walker carcinoma-256 in Sprague-Dawley rats by means of 99mTc-labelled monocytes

Labelled macrophages accumulate in Walker carcinosarcoma-256 after in vivo and in vitro stimulation with a lectin and are theretically suitable for scintigraphic tumour detection. At present, routine application of the technique in man is precluded by: (1) the use of PHA, and (2) a labelling method for macrophages with considerable limitations to its application and which results in significant uptake of activity in liver and spleen. However, the purpose of the study was primarily to demonstrate the principle of a possible alternative to the use of labelled monoclonal antibodies for the scintigraphic detection of tumours.     

Measurement of cerebral blood flow in the pig by the 133Xe clearance technique

The ¹³³Xe clearance technique is used to measure cerebral blood flow in the pig. Previous publications have shown that the two-compartmental model is inadequate for interpreting the experimental data. The present study deals with certain phenomena seen during the initial part of the clearance curves, which can lead to incorrect estimation of the blood flow rate.Two types of initial peaks can be distinguished: one is a very fast type, which is interpreted as being due to transit of the tracer via large vessels and is referred to in the literature as the arterial peak; the second is a slower tissue peak, seen in animal experiments at high CO₂ levels and in clinical patients with cerebrovascular instability.In animal preparations discrepancies were found between flow measurements according to the ¹³³Xe clearance technique and those made with the aid of an electromagnetic flow probe situated around the carotid artery. A hysteresis effect was also found in the relation between respired CO₂ level and cerebral blood flow.All these findings can be interpreted in terms of arteriovenous shunting, i.e., non-nutrient flow of blood, which is not necessarily due to anatomical anastomosis but can also be explained by the assumption that the clearance is partly limited by diffusion.The possibility of diffusion-limited clearance can have important clinical implications. Further research may provide a better basis for analysis of clearance curves to detect cerebral perfusion deficiencies that give rise to false flow calculations in present techniques.     

The reduction of inter- and intra-observer variability for defining regions of interest in nuclear medicine

The use of region-of-interest (ROI) techniques to quantify data obtained in radionuclide images is common-place. However, the reproducibility of quantitation due to inter- and intra-observer variations using particular methods of deriving ROIs is often not appreciated. We examined such variations in the results obtained by four independent observers of varying experience using four methods of depicting a ROI about an organ. The set of image data consisted of renal scans with varying target-to-background ratios, and the ROI facilities included two edge-detection methods. The results indicated that, once observers were experienced with edge-detection methods, a lower inter- and intra-observer variation could be achieved, although the technique of shrinking a ROI about a subjectively chosen display level was reasonably satisfactory. In terms or reproducibility, the least satisfactory method of depicting a ROI was the commonly used manually guided bug around arbitarily chosen display levels representing the boundary of an organ.     

Impact of CT in the neurosurgical management of intracranial tumors

Summary A total of 103 brain tumor patients examined with CT, radionuclide brain scan, and angiography or pneumoencephalography, and all surgically verified, were studied to evaluate the impact of CT on the neurosurgical handling of brain tumors. CT alone was usually sufficient for optimal handling of astrocytoma patients, angiography in most meningioma cases, and pneumoencephalography in cases with sellar, suprasellar, and some other midline tumors. Information obtained only through CT sometimes altered the therapy. Sometimes it led to biopsy instead of a meaningless attempt at a radical excision; in other cases it permitted a radical excision otherwise not possible.     

Dose to patients through nuclear medicine procedures in a department in northern Greece

Diagnostic nuclear medicine procedures in a large hospital in northern Greece during 1984–1988 have been surveyed in order to estimate the radiation burden to the patients. The mean effective dose equivalent (EDE) was found to be 1.96 mSv/examination and 2.46 mSv/patient, allowing for the fact that a number of patients underwent more than one examination. Apart from EDE, absorbed dose has been calculated for bone marrow, thyroid, gonads, kidneys and bladder. Patients undergoing multiple examinations have been used to calculate true patient dose distribution as well as patient time-weighted dose distribution. Because of the predominance of renal examinations, 8.5 fatal renal malignancies are expected per 100000 patients.     

Cerebrovascular doppler examination and cerebral angiography-alternative or complementary?

Summary Obstructions in the extracranial cerebral arteries can be detected noninvasively by directional Doppler ultrasound technique using indirect and direct criteria. The indirect criteria are based on measurement of flow in the common carotid and in the terminal branches of the ophthalmic artery before and after the common carotid artery and branches of the external carotid artery are compressed. With the direct criteria, internal and external carotid artery are differentiated by diastolic flow, and local inhomogeneities of flow (turbulence) are detected. Flow in the vertebral artery is picked up transorally in the oropharynx. The Doppler examination was used in 2230 patients of whom 436 underwent angiography. The results of Doppler and angiography correlated in more than 90% of the cases.     

Design and application of finite impulse response digital filters

The finite impulse response (FIR) digital filter is a spatial domain filter with a frequency domain representation. The theory of the FIR filter is presented and techniques are described for designing FIR filters with known frequency response characteristics. Rational design principles are emphasized based on characterization of the imaging system using the modulation transfer function and physical properties of the imaged objects. Bandpass, Wiener, and low-pass filters were designed and applied to ²⁰¹T1 myocardial images. The bandpass filter eliminates low-frequency image components that represent background activity and high-frequency components due to noise. The Wiener, or minimum mean square error filter sharpens the image while also reducing noise. The Wiener filter illustrates the power of the FIR technique to design filters with any desired frequency reponse. The lowpass filter, while of relative limited use, is presented to compare it with a popular elementary smoothing filter.This study was supported in part by National Institutes of Health Grants No. HL17646 and HL13851.     

The vascular ‘sunburst’ appearance of osteosarcoma: A new angiographic finding

The angiographic analogue of the sunburst, (right angle) periosteal new bone formation in osteogenic sarcoma is described. The angiographic findings in this tumor and their relationship to the pathologic appearance are discussed.     

81mKr gas and 99mTc-MAA V/Q ratio images for detection of V/Q mismatches

Methods for creating ventilation/perfusion ratio images have been reported previously using radioxenon. With the availability of ^81mKr gas, corresponding ventilation and perfusion views in multiple projections to evaluate for V/Q mismatch may be performed more readily. A technique for the creation of a functional V/Q ratio image to highlight V/Q mismatches to aid in the evaluation of pulmonary embolism is described. By removing nonpertinent and distracting information and by converting a cold spot imaging modality to a hot spot modality, these functional images aid in the synthesis of the information provided by the ventilation and perfusion images. The limitations due to technical artifacts and the advantages of using these functional images are described.Presented as a Scientific Exhibit at the Annual Society of Nuclear Medicine Meetings, St. Louis, Missouri, June 1983     

A quantitative approach to the analysis of the normal Thallium-201 myocardial image

The visual interpretation of Thallium-201 myocardial images is made more difficult by nonhomogeneity of myocardial tracer uptake in normal studies. To increase the objectivity of the study, the variation in count density in different myocardial areas has been calculated using a computer regions of interest technique in 14 healthy, young subjects following intravenous injection of the radionuclide at rest and in 10 after injection during maximal exercise. The normal ranges for regional Thallium-201 uptake so obtained are presented and discussed.