SPECT with N-isopropyl-p iodoamphetamine in occlusive cerebrovascular diseases

The role of SPECT imaging with N-isopropyl-p iodoamphetamine (I-123 IMP) in the detection of angiographically documented occlusive cerebrovascular diseases was evaluated in 24 patients, and the results of regional cerebral blood flow (rCBF) were compared with x-ray CT. Twelve patients had internal carotid occlusion, ten had intracranial occlusion beyond the circle of Willis, one had common carotid occlusion, and one had basilar artery occlusion. SPECT images were obtained with a gamma camera, which was rotated 360 degrees around the patient's head 30 minutes after an intravenous injection of 3 mCi of I-123 IMP. CT images in the transverse plane were obtained, and the regions of reduced attenuation were identified for comparison of topographic extension of the lesion with the regions of decreased rCBF seen on SPECT. In six cases, the lesions seen on the SPECT images were distinctly more extensive than those seen on CT. In the remaining 18 cases, the extent of the lesion was identical on both CT and SPECT images. Radiochemical and radionuclide impurities, the distance of the detector from the head, and the nature of the collimator affected the SPECT results. I-123 IMP SPECT imaging complements CT findings in detecting the ischemic zones beyond the regions identified on CT images, and may have a major rule in the management of patients with occlusive cerebrovascular diseases.

Interpolating scan and oblique-angle tomograms in myocardial PET using nitrogen-13 ammonia

The effect of low sensitivity areas or gaps between adjacent slices of the multislice positron emission tomography on detection of myocardial perfusion abnormality with 13NH3 was evaluated segmentally in 36 patients with coronary artery disease at rest or during exercise. The detectability of the defects in RCA or LAD region was 80% in single-position scans in stress studies. The false-negative defects were located mainly in the inferior wall, apicoinferior wall, or high anterior wall. When the patients were moved half the slice interval to perform the interpolating scan, and the two sets of images were interlaced with each other, the detectability increased to 88%. The interpolating scan also allowed reconstruction of long-axis and short-axis tomograms in high quality, which further improved the detectability of perfusion defects (100% for RCA or LAD and 75% for LCX lesion) and helped in understanding the anatomic relationships to the coronary artery territories.

Images of liposarcoma using technetium-99m bleomycin and technetium (V)-99m DMSA

The effectiveness of Tc-99m bleomycin (BLM) and Tc(V)-99m DMSA are compared with that of Ga-67 citrate, which is currently the most widely used agent. In four patients with lipomatous tumors, the clinical significance of tumor imaging with each of these three agents is discussed and compared. Results indicate that both Tc-99m BLM and Tc(V)-99m DMSA are superior in detecting the extension or localization of liposarcomas.

Soft-tissue uptake of technetium-99m MDP in multiple myeloma

Abnormal accumulation of Tc-99m MDP in the lungs and stomach was observed in a patient with multiple myeloma and refractory hypercalcemia. There was no roentgenographic evidence of calcification. At postmortem examination, the presence of amyloid deposits was confirmed in both organs, while the corresponding metastatic calcification was demonstrated only in the gastric mucosa. It seems likely that, in our case, soft-tissue localization of bone-seeking agent was attributable to the presence of amyloid deposits rather than metastatic calcification. No cases showing the combined occurrence of amyloid deposition and metastatic calcification in soft-tissues have previously been demonstrated to concentrate bone-seeking agent.

Centrilobular lesions of the lung: demonstration by high-resolution CT and pathologic correlation

To determine the value of high-resolution computed tomography (HRCT) in the diagnosis of diffuse pulmonary diseases, a direct HRCT-pathologic correlative study was performed using four inflated and fixed lungs from autopsy. In normal lungs, the smallest pulmonary artery resolved by HRCT was 200 microns in diameter; the artery was accompanied by the terminal bronchiole and the first-order respiratory bronchiole. The distance from the vessel to the corresponding lobular border ranged from 3 to 5 mm. These results suggest that the centrilobular area or the area around the terminal or respiratory bronchioles can be recognized with HRCT. In addition, the authors confirmed that centrilobular emphysema and centrilobular tuberculous nodules can be diagnosed with HRCT. Thus, HRCT can demonstrate the location of pathologic changes within a lobule and may be helpful in the differential diagnosis of diffuse pulmonary diseases.

Posterior lobe of the pituitary: identification by lack of chemical shift artifact in MR imaging

The posterior aspect of the normal sellar content usually displays high intensity signal on T1-weighted images. The shape, size, and location of this high intensity seem to be compatible with the posterior lobe of the pituitary gland. But fatty tissues such as intrasellar fat pad or fatty marrow of the dorsum sellae or both must be excluded as other possible sources of this high intensity signal. Two sellar phantoms were prepared. Both included high intensity posterior parts, one due to high concentration of a paramagnetic ion and the other due to fat. Magnetic resonance imaging of these phantoms showed that the fatty component was accompanied by distinct chemical shift artifacts in a predictable way. The absence of chemical shift artifact in the sellar content of normal volunteers excluded the fatty tissue as representing the high intensity posterior part. The high intensity posterior part of the normal sellar content appears to represent the posterior lobe of the pituitary gland.

Changes in thyroid-stimulating and TSH-binding inhibitory activities in a patient who developed hyperthyroidism due to Graves' disease following primary hypothyroidism

A 23-year-old female who developed thyrotoxic Graves' disease following primary hypothyroidism was reported. She presented with symptoms of hypothyroidism and slight exophthalmos. After primary hypothyroidism was confirmed, she was treated with T4 in a dose of 50 micrograms/d. Two months after delivery, 1 year after the initial diagnosis of hypothyroidism, hyperthyroidism developed while she was taking T4. Graves' disease was confirmed by persistent thyrotoxicosis, high 99mTc thyroidal uptake, negative T3 suppressibility and detection of TSH-receptor antibodies. During the hypothyroid phase, TSH-binding inhibitory immunoglobulins (TBII) could not be detected, while thyroid stimulating antibodies (TSAb) were positive showing between 5.8 and 9.0 fold increases in the amount of cAMP produced in cultured porcine thyroid cells. Her IgG did not inhibit TSH-induced cAMP increase in vitro. When she developed hyperthyroidism, TSAb activity became more potent (31.7 fold increase in cAMP) and TBII became positive (+61.3%).

Magnetic resonance imaging around the eustachian tube

Magnetic resonance imaging (MRI) of the eustachian tube, the nasopharynx, and the middle ear was performed in normal subjects and patients with ear diseases. In normal subjects, the high soft tissue contrast resolution of MRI gave a clearer view of nasopharyngeal structures compared to roentgenologic examinations including computed tomography (CT). Several cases of nasopharyngeal pathology are also presented. Nasopharyngeal carcinoma was excellently depicted, and its margin was clearly visualized. Tumor involvement of the eustachian tube and accompanying otitis media with effusion were clearly visualized. In a patient with submucous cleft palate, abnormal arrangement of levator veli palatini muscles and possible deformity of the eustachian tube cartilage were found. Magnetic resonance imaging is expected to become a valuable tool for the diagnosis of nasopharyngeal and middle ear diseases.

Clinical evaluation of radiotherapy for Graves' ophthalmopathy

Seventeen patients with moderately severe ophthalmopathy due to Graves' disease were treated by cobalt or supervoltage radiotherapy. All patients complained of diplopia. The mean proptosis value was 21.4 mm. Three patients (18%) showed good response, 7 (41%) moderate and 7 minimal or no response. Improvement was noted mainly in soft tissue changes and diplopia, while proptosis decreased in only 5 patients. All except one patient who had marked extraocular muscle involvement revealed by computed tomography responded to treatment. These data indicate that radiotherapy may be indicated in patients with progressive ophthalmopathy, especially in those who are associated with extraocular muscle enlargement.

MR imaging of cavernous hemangioma of the face and neck

Four patients with cavernous hemangioma of face and neck were evaluated with magnetic resonance imaging. Pathologically, soft tissue cavernous hemangiomas are characterized by small feeding arteries and large blood poolings. Arteriography usually fails to demonstrate the extent of the lesion. Computed tomography does not allow differentiation between these lesions and surrounding normal tissues. Magnetic resonance clearly demonstrates hemangiomas with good contrast between lesion and normal tissues. Spin-echo technique with long echo time appears to be particularly useful to delineate these lesions.

Radioimmunoimaging of human bladder tumor xenografts in nude mice by using monoclonal antibodies

Monoclonal antibodies HBJ127 and HBJ8, raised against T24 human bladder cancer cells, predominantly react with the cells in proliferating stages and with a portion of epithelial tumor cells, respectively. To investigate the in vivo localization of these monoclonal antibodies, the antibodies were labeled with radioiodine and indium-111 (111In) and injected into nude mice transplanted with human bladder tumors. The BT-11 bladder tumor had the highest concentration of radioiodinated HBJ127 and HBJ8 monoclonal antibodies, with 11.6 and 14.3% of the injected dose per gram and with a tumor-to-blood ratio of 2.6 and 1.6, respectively, at 4 days after the administration. An irrelevant monoclonal antibody did not show any specific accumulation in the BT-11 tumor. The 111In-labeled HBJ127 antibody was also localized in the tumor with a higher tumor-to-blood ratio than the radioiodinated antibody. The xenografted BT-11 tumor was successfully visualized with the radiolabeled HBJ127 and HBJ8 antibodies by scintigraphy. These monoclonal antibodies and the human bladder tumor xenografts may provide a good model for radioimmunoimaging and possibly therapy.

Stomach and duodenum: radiographic magnification using computed radiography (CR)

We performed direct radiographic magnification (X3) using a 0.1-mm microfocal tube and computed radiography (CR) in air-barium double-contrast studies of the stomach and duodenum. To eliminate blurring of the image due to motion, we used the maximum kilovolt peak rate possible (102 kVp), the maximum milliampere second rate possible (64 mAs), the shortest possible exposure time (0.1 second), and a horizontal x-ray beam. With the patients in the supine position, CR provided the wide image reproduction range required to obtain satisfactory radiographs. Image processing in the CR system produced radiographs with increased radiographic contrast and enhanced edge definition of anatomic borders or pathologic processes. The duodenal villi were clearly visible in 45% of the cases.

Femtosecond-pulse laser chirp compensated by cavity-mirror dispersion

The duration of pulses generated from a simple colliding-pulse mode-locked cw dye laser is measured as a function of cavity-mirror dispersion. The optimum amount of mirror dispersion of ø (omega) congruent with + 1.8 x 10(-28) sec(2) and a suitable mirror coating for upchirp compensation are identified. The adjustment of mirror dispersion only, without additional dispersive elements, generates continuous trains of pulses as short as 50 fsec.

Stripe sign in pulmonary perfusion scintigraphy: central pattern of pulmonary emphysema. Work in progress

Morphologic changes and ventilation abnormalities in the lung that resulted in the peripheral perfusion stripe (the stripe sign) on pulmonary perfusion scintigrams were studied in six patients. Chest radiographs, computed tomography (CT) scans, and positron emission tomography (PET) scans obtained using N-13 were compared. Although there was no apparent correlation between the presence of the stripe sign and the findings on the chest radiographs, PET scans depicted ventilation abnormalities in all of 11 lung areas with the stripe sign in six patients. In addition, ventilation was affected more severely in the central part of the lung than in the subpleural region in ten of the 11 lung areas. CT scans demonstrated emphysematous changes, with low attenuation values located mainly in the central part of the lung in all four patients examined. The results suggest an intimate relationship between the stripe sign and the central pattern of pulmonary emphysema.

Uterine cervical cancer: assessment with high-field MR imaging

Nineteen patients with histologically proved cervical carcinoma were evaluated with magnetic resonance (MR) imaging. Clinical, MR, and surgical findings were compared to determine accuracy and clinical usefulness of MR in demonstrating mass and extent of disease. MR imaging enabled clear differentiation of corpus uteri, cervix, vagina, uterine ligaments, and tumor. Tumor was demonstrated as a high-intensity mass deforming the low-intensity cervix; the low background intensity of normal structures provided high contrast to the mass. MR imaging accurately demonstrated the tumor in all ten patients with locally advanced cervical carcinoma and showed a normal cervix in nine patients with early cancer. On sagittal images, the shape of corpus uteri, cervix, and vagina, and their relationship to the mass were clearly assessed, with their long axes usually in a single plane. On axial images, assessment of parametrial tumor extension was facilitated by clear definition of the low-intensity cervix and uterine ligaments. Although more study is needed to determine the accuracy of MR in staging, MR is a promising method in evaluating cervical carcinoma.