Radioprotective effect of captopril on the mouse jejunal mucosa.

PURPOSE: Captopril, an inhibitor of angiotensin I converting enzyme, has been shown to modify radiation damage and prevent radiation injury of normal tissue in rats and pigs. The present study was carried out to determine whether captopril would reduce radiation changes in the proximal small bowel in mice. METHODS AND MATERIALS: Mice were subjected to whole body irradiation with 9 Gy or 15 Gy. Captopril was administered in drinking water at a regimen of 62.5 mg/kg/day (captopril group I) and 125 mg/kg/day (captopril group II), continuously from 7 days before irradiation to the end of each designed experiment. The jejunal damage was evaluated microscopically by crypt count per circumference and by histologic damage grading. RESULTS: Crypt number in the sham-irradiated control was 133 +/- 6.8/circumference. In both captopril group I and II, crypt numbers and histologic scores were not significantly different from those in the normal group. The 9 Gy and 15 Gy radiation alone groups showed significantly lower crypt counts and histologic scores compared with the sham-irradiated control group (p < 0.05). The groups exposed to 9 Gy radiation plus captopril I and II showed significantly higher crypt counts and lower histologic damage scores on the third day, and lower histologic damage scores on the fifth day compared with the 9 Gy radiation alone group (p < 0.05). The 15 Gy radiation plus captopril I and II groups had significantly higher crypt counts and lower histologic damage scores on the third day than those of the 15 Gy radiation alone group (p < 0.05). All mice of the 15 Gy radiation group succumbed to intestinal radiation death. CONCLUSION: Our results suggest that captopril provides protection from acute radiation damage to the jejunal mucosa in mice.

Pinhole collimator scintigraphy in differential diagnosis of metastasis, fracture, and infections of the spine.

The informational gains obtained by the use of pinhole collimator scintigraphy (PCS) have been well documented. The present study has been undertaken to prospectively investigate its efficacy in diagnosing several commonly occurring spinal diseases. Patient material consisted of metastatic cancer (39 vertebrae), compression fractures (33 vertebrae), tuberculous spondylitis (17 vertebrae), and pyogenic spondylitis (six vertebrae). PCS findings were characterized in terms of localization, appearance, and homogeneity of abnormal radionuclide accumulation. Thus, metastatic cancer manifested as diffusely or focally homogeneous accumulation within the vertebral body or as a typical short-segmental accumulation along the end-plate, whereas compression fracture manifested as characteristic board-like accumulation along the entire length of end-plates. Tuberculous spondylitis, on the other hand, revealed homogeneous accumulation throughout the vertebral body, and pyogenic spondylitis revealed accumulation at the end-zone of opposing vertebral bodies giving sandwich-like appearance. The disk space at the affected level was not narrowed in the former two diseases but it was narrowed in the latter two. It was concluded that PCS may be useful in differentiating metastatic cancer, compression fracture, tuberculous spondylitis, and pyogenic spondylitis.

Prestenotic bronchial radioaerosol deposition: a new ventilation scan sign of bronchial obstruction.

UNLABELLED: This study was performed to assess the diagnostic usefulness of aerosol ventilation scanning in bronchial obstruction and bronchial stenosis. METHODS: Seven patients of bronchial obstruction and one patient with stenosis were studied. In each patient, obstruction was confirmed by bronchography, bronchoscopy and/or CT scan. Ventilation scanning was performed using the 99mTc-phytate aerosol generated by a BARC jet nebulizer. Scan manifestations were assessed in correlation with those of plain chest radiography, bronchography, CT scan and/or bronchoscopy. RESULTS: In every patient, the ventilation scan showed characteristic intense aerosol deposition in a short, slightly dilated, clubbed, bronchial segment immediately proximal to obstruction or stenosis. Typically, it was accompanied by a distal airspace deposition defect. CONCLUSION: Intense, segmental, bronchial aerosol deposition with distal lung defect was a specific finding of bronchial obstruction and stenosis. The sign was especially useful when obstruction was obscured by the associated, bizarre lung disease and in a small bronchus.

Pinhole scintigraphic sign of chondromalacia patellae in older subjects: a prospective assessment with differential diagnosis.

UNLABELLED: Chondromalacia patellae (CP) is an important cause of anterior knee pain. Two clinical types are known: one that typically affects young subjects and the one that affects older patients. The primary diagnostic approach is radiography reinforced with arthrography. A 99mTc-MDP bone scan is invaluable in the study of bone diseases especially when augmented with pinhole scintigraphy (PS). In this study previously unknown, specific sign of CP demonstrated by PS in six middle-aged and elderly patients is described. METHODS: Noting an increased patellar uptake in a planar spot view, a medial PS scan of the patella was taken to detail the uptake pattern using a 3-mm or 4-mm aperture pinhole collimator. The uptake pattern was analyzed in terms of location, definition, mode, grade and other associated changes, and correlated with radiographic and CT scan alterations. RESULTS: The planar views showed patellar uptake to be diffuse and nonlocalizing in five patients and ill-defined and spotty in the remaining patient. In contrast, PS revealed small, spotty uptake well localized in the central retropatellar facet in all but one patient in whom uptake was segmental. A control PS study of 16 patients with their patellas involved by osteoarthritis (n = 6), rheumatic arthritis (n = 5) and Reiter's syndrome (n = 5) also revealed retropatellar uptake with or without anterior patellar uptake in every patient. The CP with localized osteolysis or osteopenia accumulated tracer intensely, whereas those without showed mild to moderate uptake. CONCLUSION: Spotty tracer uptake occurring exclusively in the central retropatellar facet without other knee joint alteration appears pathognomonic of CP in older patients.

Bone pathologic correlation of multimodality imaging in Paget's disease.

The pagetic bones in the active phase of the disease with brisk lysis and sclerosis manifest intense tracer uptake on planar bone and SPECT images. Intense tracer uptake, however, can occur also in infections, dysplasias and metastases. Pinhole bone scintigraphy has been shown to portray specific diagnostic signs in a number of skeletal diseases. In an effort to identify useful bone scan signs, we prospectively carried out 99mTc-oxidronate pinhole bone scintigraphy of the skull, vertebrae, ribs, humerus, sacrum and ilium in two patients with Paget's disease of the bone. The pinhole bone scintigraphy findings correlated with radiographic, CT and MRI findings and in the vertebra with the pathological study. Interestingly enough, pinhole bone scintigraphy revealed intense tracer uptake preferentially in the bone cortex and the rim of the affected bones. Thus, the cranial inner table, humeral cortex and vertebral endplates and rims were the seats of characteristic tracer uptake, respectively creating a scintigraphic version of the radiographic "cotton wool" sign, "casket" sign and "picture frame" sign. The pagetic lesions in the sacrum and ilium also showed intense cortical and rim uptake. Correlation of pinhole bone scintigraphy with radiography, CT and MRI indicated that such cortical or rim uptake is characteristic of Paget's disease.

Dual-head pinhole bone scintigraphy.

UNLABELLED: This article describes dual-head pinhole bone scintigraphy (DHPBS), which makes use of two opposing pinhole-collimated detectors to obtain one pair of magnified images of bone and joint at one time. The aims are to reduce scan time and solve the problem of the blind zone that is created in the background in single-head pinhole bone scintigraphy. METHODS: DHPBS was used for normal hip and knee joints and one case each of lumbar spondylosis, vertebral compression fracture and pyoankle. The gamma camera used was a digital dual-head SPECT camera (Sopha Camera DST; Sopha Medical Vision International, Buc Cedex, France) connected to an XT data processor and a printer. Each of two opposing detectors was collimated with either a 3- or 5-mm pinhole collimator. The scan was performed 2-3 hr postinjection of 12-25 mCi 99mTc-oxidronate. Some 1500-2000 Kilocounts were accumulated at 15-40 min per pair. Anterior and posterior views were taken for the spine and hip and medial and lateral views for the knee and ankle. DHPBS images were correlated to radiographs. RESULTS: DHPBS produced a pair of high-resolution bone and joint images at one time, reducing scan time by nearly half for each image. The paired DHPBS images clearly visualized both foreground and background objects, which effectively eliminated the blind zone. CONCLUSION: DHPBS can significantly improve efficiency and diagnostic acumen.

Pinhole SPECT imaging in normal and morbid ankles.

UNLABELLED: Pinhole SPECT can generate sectional nuclear images of a normal and morbid ankle and hindfoot with remarkably enhanced resolution by portraying the topography and pathological alterations in great detail. METHODS: Pinhole SPECT was performed using a commercially available single-head, rotating gamma camera system by replacing the parallel-hole collimator used for planar SPECT with a pinhole collimator. The images were reconstructed in the same way as in planar SPECT by using the filtered back-projection algorithm and a Butterworth filter. First, we compared the scan resolution between the planar and pinhole SPECT images of a thyroid phantom and a normal ankle and hindfoot by working out pinhole SPECT anatomy with CT validation. Second, the clinical usefulness was assessed in one case each of fracture, reflex sympathetic dystrophy syndrome and rheumatoid arthritis of the ankle with radiographic correlation. The resolution of the pinhole SPECT and planar pinhole images was compared for these diseases. RESULTS: The resolution of the pinhole SPECT of a thyroid phantom and of a normal ankle and hindfoot was significantly enhanced compared to the planar SPECT although image distortion was seen in the periphery of the field-of-view. The pinhole SPECT resolution was such that most of the anatomical landmarks were sharply delineated in the ankle and hindfoot and some useful diagnostic signs in the diseased ankle were visible. CONCLUSION: Pinhole SPECT can be performed using a single-head gamma camera system and filtered back-projection algorithm. It generates sectional scan images of both normal and morbid ankle and hindfoot with enhanced resolution portraying many anatomical landmarks and pathological signs in useful detail.

Measure-set computed tomographic analysis of internal architectures of lumbar disc. Clinical and histologic studies.

Measure-set computed tomography (MSCT) scan was performed in 30 adult subjects (17 men and 13 women, mean age 42 years) and eight cadavers (five men and three women, mean age 42 years) to establish prospectively a normal CT pattern of the internal architectures of the lumbar disc. Based on the uniformity or nonuniformity of MSCT composition of the nucleus pulposus (NP) and annulus fibrosus (AF), and also on how well NP was discerned from the surrounding AF, the internal architecture could be categorized into well-defined (WD), intermediate (IM), and ill-defined (ID) types. An age and prevalence study of the categorized disc showed that, with age, the disc undergoes an architectural transformation from WD through IM to ID. In addition, 72.5% of WD-type discs and 72.1% of ID-type discs occurred in the third and fourth decades and in the sixth and seventh decades, respectively, suggesting that the former is a young form with mild degeneration and the latter an old form with advanced degeneration. Fifty-eight percent of WD-type discs and 60.4% of ID-type discs occurred at L1-3 and L4-S1 levels, respectively, regardless of age. This finding suggests the old form tends to occur at the lumbosacral junction, which is the site of maximum weight bearing in humans. The correlation of water content and histologic findings of degeneration with the three categorized disc types in cadavers showed that WD, IM, and ID discs were associated with the largest, intermediary, and least amount of water of NP, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer-aided design optimization with the use of a fast dose model for linear-accelerator-based stereotactic radiosurgery.

In order to efficiently plan non-spherical radiosurgical targets we have used computer-aided design optimization techniques with a fast dose model. A study of the spatial dose distribution for single or multiple non-coplanar arcs was carried out using a 18 cm diameter spherical head model. The dose distribution generated from the 3D dose computation algorithm can be represented by a simple analytic form. Two analytic dose models were developed to represent the dose for preset multiple non-coplanar arcs or a single arc: spherical and cylindrical. The spherical and cylindrical dose models compute dose quickly for each isocentre and single arc. Our approach then utilizes a computer-aided design optimization (CAD) with the use of two fast approximate dose models to determine the positions of isocentres and arcs. The implementation of CAD with fast dose models was demonstrated. While the fast dose models are only approximations of the true dose distribution, it is shown that this approximate model is sufficient to optimize isocentric position, collimator size and arc positions with CAD.

1H magnetic resonance spectroscopy characterization of neuronal dysfunction in drug-naive, chronic schizophrenia.

RATIONALE AND OBJECTIVES: We investigated the proton metabolism of right prefrontal white matter in drug-naive, chronic schizophrenic patients (n = 23), compared with healthy normal control subjects (n = 10), by using localized, water-suppressed in vivo 1H magnetic resonance (MR) spectroscopy. METHODS: All 1H MR spectroscopy examinations were performed on a 1.5-T MR imaging/MR spectroscopy system by using a point-resolved spectroscopy pulse sequence for localized volumes of 2 x 2 x 2 cm3. Proton metabolite ratios relative to creatine (Cr) were obtained using a Marquart algorithm. RESULTS: Drug-naive, chronic schizophrenic patients demonstrated a decrease in the N-acetylaspartate (NAA):Cr and choline (Cho):Cr ratios and an increase of the complex of gamma-aminobutyric acid (GABA) and glutamate (Glu)-containing ratio [(GABA + Glu):Cr] as compared with normal control subjects. CONCLUSION: Results suggest that the reduction of NAA and Cho may indicate neuronal dysfunction and that the elevation of GABA and Glu may play a role in chronic schizophrenia. 1H MR spectroscopy may be a useful modality in research and in the clinical evaluation of chronic schizophrenic patients.

Radiologic manifestations of epidemic haemorrhagic fever with renal syndrome.

Epidemic haemorrhagic fever is a viral disease characterized by acute febrile onset followed by profound renal dysfunction. The endemic areas are widespread throughout the Eurasian continent and the Japanese islands. The patient with EHF usually seeks medical care as an emergency for an "acute abdomen". Consequently the X-ray examination becomes an essential part of the clinical study. We analysed the plain abdomen and chest films of 62 patients with this disease. The radiologic manifestations represented diffuse capillary damage with resultant oedema and haemorrhage, particularly in the retro-peritoneal space. Abnormal findings were seen in 94% of the patients on the plain abdomen, and in 63% on the chest film. The most significant finding was obliteration and blurring of anatomical detail in both intra- and retro-peritoneal cavities and renal enlargement. We believe that simultaneous presence of oedema and effusion in both intra- and retro-peritoneal cavities along with renal enlargement is in practice pathognomic of EHF. Obliteration of the renal outline and cardiomegaly with overt lung oedema was associated with the most severe renal dysfunction.

Optimisation of dose distribution for linear accelerator-based stereotactic radiosurgery.

The work presented in the paper addresses a method for obtaining the optimal dose distribution for LINAC-based stereotactic radiosurgery. As many targets have nonspherical or irregular shapes and three-dimensional dose calculations included in dose optimisation, long computation times are required to determine the optimum isocentre separation and collimator sizes to shape the irregular target using the multiple-isocentre approach, by trial-and-error types of method. The simple approach, using a computer-aided design optimisation technique and a fast approximate dose model, has been developed to find the optimum isocentre positions and collimator sizes quickly and automatically. A spherical dose model has been developed to represent the dose for a standard arc system with a single isocentre. The implementation of computer-aided design algorithms with the spherical dose model and their application to several cases are discussed. It is shown that the spherical dose model gives dose distribution similar to that of the exact dose model, which makes this simple dose model more efficient, with computer-aided design optimisation, in finding optimum isocentre positions and collimator sizes used in stereotactic radiosurgery.

Peripheral upper lobe collapse simulating pleural effusion.

Two cases of segmental collapse of the upper lobe simulating an apical pleural effusion in association with pneumothorax are reported. Our cases differ from previously reported ones in that the peripheral collapse occurred in association with a pneumothorax without pleural adhesions, it was segmental rather than lobar, and was observed in adults.

Measure-set computed tomography in the diagnosis of herniated nucleus pulposus.

The present study has been carried out to enhance the specificity of computed tomography (CT) in diagnosing herniated nucleus pulposus (HNP) of the lumbar spine by the application of measure-set (MS) technic. MSCT scans of 20 patients with proven diagnosis of HNP were reviewed prospectively to sort out features of diagnostic value. Eleven were men and 9 were women with the mean age being 40 years. MSCT scan revealed dislocation of the center of the nucleus pulposus (NP) in direction of herniation in 75%, "permeation" of the annulus fibrosus (AF) by HNP material and a clear disruption of the outermost layer of AF in all patients. The site and grade of the protrusion of HNP beyond the normal saliancy of AF could be easily evaluated in 90%. The present study saliancy of AF could be easily evaluated in 90%. The present study revealed that MSCT can demonstrate four characteristic findings of HNP enabling one to directly and semiquantitatively assess the pathologic changes of NP.

Postural relief of food impaction in a patient with stenosed esophagus--a case report.

A patient with past history of esophageal stenosis complained of sudden dysphagia in the erect position which was relieved transiently in the supine position. Initial esophagoscopy failed to detect any mass in the lumen. Esophagogram revealed shifting foreign body from lower stenotic site to upper dilated area with postural change from the erect to the supine position. A French bean was detected and removed during the second esophagoscopy.

Use of film duplicator to lighten dark radiographs.

The authors introduce a simple technique for lightening overexposed or overdeveloped dark radiographs. With the technique, an increase of exposure time in film duplicator allows production of duplicate radiographs with an appropriate tone. With this manipulation, image details are greatly improved, and the original radiograph is not damaged.