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.

Clinical results of 24 pituitary macroadenomas with linac-based stereotactic radiosurgery.

PURPOSE: To determine the impact of stereotactic radiosurgery (SRS) on the clinical course, hormonal status, and follow-up CT/MRI scan of pituitary macroadenomas. METHODS AND MATERIALS: From July 1988 to March 1996, 24 pituitary macroadenomas had been treated using 6 MV linear accelerator based SRS. They consisted of 11 (45.8%) prolactinomas, 2 (8.3%) growth hormone (GH)-secreting tumors, 1 (4.2%) Cushing's disease, 8 (33.3%) nonsecreting (nonfunctioning: NF) tumors, and 2 (8.3%) mixed prolactin-growth hormone (PRL-GH)-secreting tumors (M:F = 12:12; aged 21-61 years). Postoperative irradiation was performed in all cases except for the instance of Cushing's disease. The prescribed dose to tumor center varied from 10 to 27 Gy (mean 21.1 Gy) using a collimator size of 0.5 to 2.5 cm. The follow-up duration ranged from 13 to 89 months (mean 49.2 months). Results from these patients were compared to our results using conventional radiation. RESULTS: Visual acuity and field defect were improved or became normal in 19 (79.2%) cases. Four (16.7%) remained unchanged after the treatment. One (4.1%) progressed 6 years after SRS and subsequently had repeat surgery with conventional boost irradiation. Of the 13 (46.4%) prolactinomas, including two mixed PRL-GH secreting tumors, 11 (84.1%) revealed normal hormonal levels within 1 year after SRS. In contrast, it took 2 years to become normal after conventional radiation therapy. In four GH-secreting tumors including two mixed PRL-GH secreting tumors, SRS and conventional methods showed similar responses. On follow-up imagings of the 21 patients, the mass was completely resolved in 4 (16.7%), including 3 PRLs and one NF, decreased in 11 (45.8%), and unchanged in 5 (16.7%) with central necrosis or cysts. One (4.2%) progressed and was reoperated 6 years after treatment. The complications related to SRS were comparable to those from conventional method. CONCLUSION: Radiosurgery can be used effectively in patients with pituitary adenoma. In this study, a more rapid hormonal and clinical response was achieved with radiosurgery than with conventional pituitary irradiation treatment.

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.

Radiologists' responses to patients' inquiries about imaging results. A pilot study on opinions of various groups.

RATIONALE AND OBJECTIVES: The authors analyzed opinions regarding how a radiologist should answer a patient's or patient's family's questions about radiologic results. METHODS: Questionnaires were obtained in a university hospital from 135 physicians of various specialties, including radiologists, and 501 nonphysicians, such as medical students, nurses, patients, families of patients, and hospital personnel. The questionnaire included three questions, each with five choices. The first question concerned a normal result, the second a minor abnormality, and the third a major abnormality. The five choices in each question consisted of two suggestive answers to patients' inquiries and three excuses for the refusal of immediate answers. Respondents were asked to choose the single most desirable and the single least desirable answer. RESULTS: Approximately 50% of all physicians believed that a radiologist should refer the patient to his or her physician rather than to give a suggestive answer to a patient with an abnormality. Considerably fewer physicians had a similar opinion in cases involving a patient with normal results. Patients and the families of patients believed that a radiologist should give at least a suggestive answer in any circumstances where the patient is agitated to know the result. Radiologists were reluctant to convey any information regardless of the test result. CONCLUSIONS: Physicians had significantly different opinions from patients and the families of patients, and radiologists preferred to keep their traditional role of referral physician.

Postmortem metabolic and morphologic alterations of the dog brain thalamus with use of in vivo 1H magnetic resonance spectroscopy and electron microscopy.

RATIONALE AND OBJECTIVES: To investigate postmortem metabolic and morphologic alterations in the dog brain thalamus and to contribute diagnostic aids in medicolegal science. METHODS: A homogeneous group of 17 dogs was used for in vivo 1H magnetic resonance (MR) spectroscopy and electron microscopic studies, which were performed under intravenous and intramuscular anesthesia before and after the dogs were killed. All 1H MR spectroscopy and electron microscopy examinations were performed on a 1.5 T MR imaging/MR spectroscopy system using a stimulated-echo acquisition mode pulse sequence and an electron microscope, respectively. RESULTS: The lactate resonance signal, which could be used as a criterion for tissue survival, appeared during the entire postmortem period. The lactate: creatine ratio significantly increased in the early postmortem metabolic process. The inositol: creatine ratio showed a mild gradual increase. However, the N-acetyl-aspartate: creatine and choline/creatine ratios generally were unchanged. The decomposition of proton metabolites was observed in the MR spectrum 48 hours postmortem. In the postmortem period, high power field (x10,000) electron microscopic results showed significant morphologic alterations of the thalamus, revealing nuclear pyknosis and perikaryal condensation, cytoplasmic vacuoles, clumping of nuclear chromatin, and destruction of cellular organelles and nuclear membrane. CONCLUSIONS: Results suggest that the combination of 1H MR spectroscopy and electron microscopy may simultaneously provide good quality metabolic and morphologic information of cerebral tissue in the field of thanatochronology.

Evaluation of the effects of high dose irradiation on canine thigh muscle by follow-up magnetic resonance imaging and phosphorus-31 magnetic resonance spectroscopy.

RATIONALE AND OBJECTIVES: The authors investigate alterations of proton T1 and T2 relaxation times and phosphorus metabolites of canine thigh muscle tissue after high dose x-ray irradiation by follow-up magnetic resonance imaging (MRI) and phosphorus-31 (31P) magnetic resonance spectroscopy (MRS). METHODS: A group of 20 dogs was used for MRI and in vivo 31P MRS. Single doses of 5,000 and 10,000 cGy were delivered to the right thigh muscle of groups of 10 dogs each. All MRI and 31P MRS examinations were performed before irradiation and 1, 7, 14, 28, 42, and 56 days after irradiation. For measurement of T1, repetition time (TR) was measured at 300, 500, 1000, 1500, 2000 msec and echo time (TE) was fixed at 12 msec. Also, for measurement of T2, TE was measured at 20, 40, 60, and 80 msec and TR was fixed at 2000 msec. Image selected in vivo spectroscopy (ISIS) pulse sequence was used to obtain 31P MR spectra. Peak areas for each phosphorus metabolite were measured using a Marquart algorithm. RESULTS: Magnetic resonance imaging signal began to change at 28 days after a single dose of 10,000 cGy, whereas there was no significant MRI signal change until 56 days after a single dose of 5,000 cGy. Also, extensive MRI signal changes were observed at 42 days after a single dose of 10,000 cGy. Significant correlation was established between T2 and a lapse of time although there was no correlation between T1 and a lapse of time. T2 value increased substantially corresponding to the time period after x-ray irradiation. Although MR spectral change was not observed until 42 days after a single dose of 5,000 cGy, it began at 14 days after a single dose of 10,000 cGy. And, significant MR spectral changes were observed at 28 and 42 days. Inorganic phosphate and phosphodiesters signal intensities increased while phosphocreatine signal intensity decreased. The pH value was 7.22 +/- 0.05 at control, and 6.98 +/- 0.04 at 42 days after a single dose of 10,000 cGy. CONCLUSIONS: The postirradiation follow-up MRI and 31P MRS studies demonstrated that morphologic and metabolic changes were dependent upon the x-ray dose and a lapse of time.

Neuronal dysfunction in patients with closed head injury evaluated by in vivo 1H magnetic resonance spectroscopy.

RATIONALE AND OBJECTIVES: With the use of localized, water-suppressed in vivo 1H magnetic resonance spectroscopy (MRS), the proton metabolic alterations of white matter in patients with closed head injury (CHI) and healthy controls are evaluated, and metabolic alterations with Glasgow Outcome Scale (GOS) scores are compared. METHODS: Patients with CHI (n = 10) and healthy control subjects (n = 10) underwent MRS examinations using a stimulated-echo acquisition mode pulse sequence that provided 2 x 2 x 2 cm3 volume of interest in the left frontoparietal white matter. Proton metabolite ratios relative to creatine were obtained using a Marquart algorithm. RESULTS: The specific feature in patients with CHI was significant decrease of N-acetylaspartate (NAA)/creatine ratio compared with normal controls. No clear correlation of other metabolite ratios such as choline/creatine and inositols creatine was established. The level of NAA/creatine ratio was significantly correlated with GOS. CONCLUSIONS: Results of this preliminary study suggest that the reduction of NAA/creatine ratio may indicate neuronal loss in patients with CHI. The NAA/creatine ratio may serve as a metabolic criterion to predict the GOS of patients with CHI. Thus, in vivo 1H MRS may be a useful modality in the clinical evaluation of patients with CHI based on the proton metabolite concentrations of cerebral white matter.

Observation of metabolic changes in chronic schizophrenia after neuroleptic treatment by in vivo hydrogen magnetic resonance spectroscopy.

RATIONALE AND OBJECTIVES: The authors investigate: (1) whether there is a lateral effect of hydrogen (1H) magnetic resonance (MR) spectroscopy observable metabolite ratios between the right and the left prefrontal lobe in chronic schizophrenia; (2) whether there is a change of proton metabolite ratios in chronic schizophrenia after neuroleptic treatment; (3) whether there is a relation between changes in 1H MR spectra and the clinical assessment of Brief Psychiatric Rating Scale (BPRS); and (4) to investigate a hypofrontality hypothesis in schizophrenia in terms of neurochemical aspects. METHODS: Localized in vivo 1H MR spectroscopy was used to measure the metabolite levels in the prefrontal lobes of control persons (n = 20) and of chronic patients before and after neuroleptic treatment (n = 34). The MR spectra of 8 cm3 voxels were compared with clinical assessment of BPRS in each subject. RESULTS: No significant metabolic lateral effect was established in both schizophrenia and control groups (P > 0.05). After neuroleptic treatment, chronic schizophrenic patients generally demonstrated a decrease of the complex of gamma-aminobutyric acid (GABA) and glutamate (Glu) containing (GABA + Glu)/creatine (Cr) ratio. CONCLUSIONS: The current follow-up 1H MR spectroscopy study shows a significant correlation between alterations of (GABA + Glu)/Cr ratio and BPRS, and supports a hypofrontality hypothesis in chronic schizophrenia. The reduction of (GABA + Glu)/Cr ratio after neuroleptic treatment may implicate the recovery of normal neuronal function in neurotransmitters. In vivo 1H MR spectroscopy may be a useful modality in follow-up evaluation of neuroleptic treatment in chronic schizophrenia.

Neuronal laterality in Parkinson's disease with unilateral symptom by in vivo 1H magnetic resonance spectroscopy.

RATIONALE AND OBJECTIVES: The authors investigate whether there is a lateral effect of 1H-magnetic resonance spectroscopy (MRS) observable metabolite ratios between the symptomatic and the asymptomatic side in Parkinson's disease with unilateral symptoms. METHODS: Localized in vivo 1H MRS was used to measure the metabolite levels in the symptomatic and the asymptomatic sides of the substantia nigra (SN) and putamen-globus pallidus (PG) in Parkinson's disease with unilateral symptom (n = 15). The metabolite ratios of N-acetylasparatate (NAA)/creatine (Cr), and choline-containing compounds (Cho)/Cr in the symptomatic side were compared with those in the asymptomatic side. According to the symptomatic duration, the authors evaluated whether there was a specific correlation between laterality and the clinical stage. RESULTS: Significant metabolic lateral effect of NAA/Cr ratio was established between the symptomatic and the asymptomatic sides of SN and PG in Parkinson's disease with unilateral symptoms (P = 0.03). The decreased NAA/Cr ratio was calculated in at least one of the selected regions in SN and PG, indicating neuronal loss. The main observations were that NAA/Cr ratios were reduced in the left symptomatic side (n = 7; P = 0.001) and reduced to a lesser degree in the right symptomatic side (n = 8; P = 0.03 [PG], P = 0.21 [SN]) and that there was no significant laterality of other metabolite ratios. CONCLUSIONS: On the basis of NAA/Cr ratios between the symptomatic and the asymptomatic sides, the present 1H MRS study shows a significant neuronal laterality in Parkinson's disease with unilateral symptoms. In vivo 1H MRS may provide a diagnostic marker for neuronal dysfunction in Parkinson's disease with unilateral symptoms.

Idiopathic transverse myelitis: MR characteristics.

PURPOSE: To describe the MR characteristics that can distinguish idiopathic transverse myelitis from other intramedullary lesions. METHODS: A total of 32 initial and follow-up MR studies in 17 patients with clinically proved transverse myelitis were reviewed retrospectively. The location, size, pattern, and segmental length of areas of hyperintensity were estimated on T2-weighted axial and sagittal images. In 15 of the patients, whose neurologic abnormalities were limited to the spinal cord, the location and pattern of intramedullary contrast enhancement were evaluated on sagittal and axial T1-weighted images. Follow-up MR studies were available for 10 patients. The statistical significance of cord enhancement between the groups with and without cord expansion was calculated. RESULTS: Common MR findings of idiopathic transverse myelitis included a centrally located hyperintensity occupying more than two thirds of the cross-sectional area of the cord (88%); a length of 3 to 4 vertebral segments (53%), with variable presence of cord expansion (47%); a small central area of intensity, isointense with normal cord, in the core of hyperintensity (47%); focal, peripheral cord enhancement (53%), particularly in patients with cord expansion; and a slow regression of T2 hyperintensity with an enhancing nodule. Although no linear correspondence was observed between MR findings and neurologic signs and symptoms, all but 4 patients improved clinically as MR findings improved or remained stable. CONCLUSIONS: MR findings are helpful in detecting transverse myelitis and in differentiating this entity from multiple sclerosis and cord tumors, but clinical assessment and observation of MR changes over time are essential in making the diagnosis.

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.

Benign solitary fibrous tumour of the pre-sacral space: MRI findings.

Benign solitary fibrous tumour, a rare mesenchymal tumour of adults, usually arises from the pleura. Only a few cases have been reported in the retroperitoneum and, to our knowledge, there has been no report of its imaging features. We describe the MRI features of benign solitary fibrous tumour arising from the pre-sacral space.

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.

Postnatal growth of fetus-in-fetu.

A 6-month-old-boy who presented with an abdominal mass disclosed a well-formed fetus in the retroperitoneum. This mass was retrospectively noted at the age of 1 month. Comparison of two radiographic examinations done 5 month apart clearly demonstrated the enlargement of an included fetus in the bearer's abdomen. Our report of this rare condition focuses on the growth of the fetus-in-fetu detected by roentgenograms.

The air meniscus sign in sclerosing hemangioma of the lung.

The air meniscus sign occurs in a number of lung conditions, including infection, benign and malignant tumors, and hematoma. Sclerosing hemangioma does not appear to have been implicated previously in this connection. Two such cases are described. Possible mechanisms of air meniscus formation and its diagnostic value in sclerosing hemangioma are discussed.

Adrenal paragonimiasis simulating adrenal tumor--a case report.

We describe a case of adrenal paragonimiasis with its computed tomographic and ultrasonographic findings. Computed tomogram showed a well enhancing oval mass at right adrenal gland and ultrasonogram showed a dumbbell-shaped hyperechoic mass saddling on the top of the right kidney. Surgical specimen was multicystic mass filled with creamy material.

Local recurrence after surgery for gastric carcinoma: CT findings.

Local recurrence of gastric carcinoma after surgery is defined as histologic evidence of a tumor in the surrounding tissues of the resected stomach. Compared with the large number of articles describing tumor recurrence after colectomy for colonic carcinoma, few reports have been published on the CT findings after gastrectomy. We illustrate the CT features of local tumor recurrence after gastrectomy in 36 patients in whom recurrence was confirmed pathologically or by definitive findings on CT scans.

Lung abscess. Percutaneous catheter therapy.

Lung abscess was successfully treated with percutaneous drainage in 5 of 6 patients. Complete abscess resolution occurred in 4 patients, partial resolution in one, and no response in one. The duration of drainage ranged from 7 to 18 days (mean 15.5 days) in successful cases. The failure of drainage in one neurologically impaired patient was attributed to persistent aspiration. In 2 patients, concurrent pleural empyema was also cured. CT provided the anatomic details necessary for choosing the puncture site and avoiding puncture of the lung parenchyma. Percutaneous catheter drainage is a safe and effective method for treating lung abscess.