Diffuse, intense lung uptake on a bone scan: a case report.

PURPOSE: Clinical and scintigraphic findings are described in a patient with unexpected diffuse lung uptake on bone scan after a heroin overdose. METHODS: The patient's Tc-99m MDP bone scan is reviewed along with the pertinent clinical history and laboratory findings. RESULTS: Marked diffuse and symmetric lung uptake is present on bone scintigraphy in a patient with a history of acute renal failure and a markedly elevated calcium-phosphate product but normal renal function and laboratory values at the time of the examination. CONCLUSIONS: The incidental observation of metastatic calcification by bone scintigraphy is important, because it may aid in the diagnosis of a previously unsuggested elevated calcium-phosphate product, renal failure, or both. Furthermore, the intensity of tracer localization on bone tracer-specific imaging may help evaluate the activity of the metastatic calcification process.

A practical double-tuned 1H/31P quadrature birdcage headcoil optimized for 31P operation.

A double-tuned 1H/31P birdcage head coil for use with humans at 1.5 T is described. The coil was designed for proton-decoupled 31P excitation and reception and incorporated a number of practical features including optimized sensitivity for 31P, quadrature operation at 1H and 31P frequencies, and a radiofrequency (RF) mirror for improved B1 homogeneity. The design achieved similar B1 homogeneity at both 31P and 1H frequencies. Inductive matching was used to accommodate samples with large loading differences. A facile method for tuning and matching over a variety of sample loadings is presented, along with capacitively shortened bazookas for suppression of cable braid currents. The proton sensitivity, although down by approximately a factor of two compared with an optimized 1H birdcage head coil, was still ample for shimming and generation of scout images. Advantages of the design are discussed and proton-decoupled 31P spectra of human brain are presented.

Brain mapping with single photon emission CT.

PURPOSE: To investigate the feasibility of performing brain mapping studies by using cortical activation paradigms and single photon emission computed tomography (SPECT) and to evaluate methods of analysis. MATERIALS AND METHODS: Twenty healthy volunteers underwent technetium-99m bicisate SPECT under baseline conditions and during either full-field or right hemifield visual stimulation with a black and white reversing checkerboard pattern. Changes in regional cerebral perfusion were measured by using regions of interest (ROIs) and statistical parametric mapping. RESULTS: ROI analysis identified statistically significant increases in perfusion in the occipital cortex with full-field visual stimulation (mean +/- standard error of the mean percentage change from baseline: left, 8.0 +/- 1.5; right, 6.6 +/- 2.4). With right hemifield visual stimulation, perfusion was significantly increased only in the left occipital cortex (left, 5.2 +/- 1.5; right, -0.2 +/- 1.9). Statistical parametric mapping showed areas of activation (more than 100 voxel clusters showed significant change from baseline at a threshold value of P < or = .005 or z > or = 2.58) in the left primary visual cortex (right hemifield visual stimulation) and in both right and left primary visual areas (full-field visual stimulation). CONCLUSION: Brain mapping studies were preformed with Tc-99m bicisate SPECT, and activation-induced changes were visualized and measured. These methods can be applied to develop improved methods of diagnosis and assessment of treatment outcome in patients with neuropsychiatric disorders.

Discordance of dual-isotope (hybrid) myocardial perfusion imaging results in patients who have undergone revascularization procedures.

Three hundred twenty-one separate acquisition dual-isotope myocardial perfusion scans were reviewed retrospectively. Studies performed in six patients demonstrated a relative improvement in Tc-99m sestamibi uptake during stress in segments that appeared abnormal on rest injected Tl-201 images. All patients who demonstrated this pattern had a prior history of myocardial infarction and interventional revascularization. While many factors may contribute to this appearance, the authors favor the presence of a patent infarct-related artery as being the most significant.

Characterization of technetium-99m-L,L-ECD for brain perfusion imaging, Part 1: Pharmacology of technetium-99m ECD in nonhuman primates.

Technetium-99m ethyl cysteinate dimer ([99mTc]ECD) is a neutral, lipophilic complex which rapidly crosses the blood-brain barrier. Brain retention and tissue metabolism of [99mTc]ECD is dependent upon the stereochemical configuration of the complex. While both L,L and D,D enantiomers are extracted by the brain, only the L,L but not the D,D form, is metabolized and retained in the monkey brain (4.7% injected dose initially, T 1/2 greater than 24 hr). Dynamic single photon emission computed tomography imaging studies in one monkey indicates 99mTc-L,L-ECD to be distributed in a pattern consistent with regional cerebral blood flow for up to 16 hr postinjection. Dual-labeled 99mTc-L,L-ECD and [14C]iodoantipyrine autoradiography studies performed 1 hr after administration show cortical gray to white matter ratios of both isotopes to be equivalent (approximately 4-5:1). These data suggest that 99mTc-L,L-ECD will be useful for the scintigraphic assessment of cerebral perfusion in humans.

Biodistribution, dosimetry, and clinical evaluation of technetium-99m ethyl cysteinate dimer in normal subjects and in patients with chronic cerebral infarction.

Technetium-99m ethyl cysteinate dimer (ECD) has high initial cerebral uptake with slow clearance in nonhuman primates suggesting ideal characteristics for single photon emission computer tomography (SPECT) imaging. We evaluated the biodistribution, dosimetry and scintigraphic pattern of [99mTc]ECD in normal subjects and the accuracy of SPECT imaging in patients with chronic cerebral infarction. Sixteen normal subjects were injected with approximately 10 mCi of [99mTc]ECD. Anterior and posterior single-pass whole-body images were obtained at multiple times after injection. Blood clearance of the radiotracer was rapid, falling to 10.0 +/- 6.6% and 4.9 +/- 1.1% of the injected dose at 2 and 60 min, respectively. Brain uptake was 6.4 +/- 2.1% of the injected dose 5 min after injection. The critical organ was the urinary bladder. Technetium-99m ECD SPECT was performed with a rotating gamma camera in ten of the 16 normal subjects and 34 patients with clinical and CT evidence of chronic stroke. Thirty-three of the thirty-four patients had focal [99mTc]ECD abnormalities on SPECT (97.1%) based on visual inspection of the SPECT images. In summary, we obtained high quality SPECT images as a result of the optimal physical and biologic characteristics of the tracer. Technetium-99m ECD SPECT shows promise for the evaluation of patients with stroke.

Sphincter of Oddi stenosis: diagnosis using hepatobiliary scintigraphy and endoscopic manometry.

To determine the role of radionuclide imaging in diagnosing sphincter of Oddi stenosis, 21 patients with symptoms suggesting this disorder underwent endoscopic retrograde cholangiopancreatography, cholescintigraphy, and, when possible, endoscopic manometry. Those patients with abnormal hepatobiliary scintigraphy results--based on our criteria of delayed biliary intestinal transit, abnormal duct size, and abnormal time-activity dynamics and obstruction--had a mean basal sphincter pressure of 38.5 mm Hg. Sphincter pressures could not be measured in six patients with sphincters too tight to cannulate. Ten patients who underwent hepatobiliary scanning both before and after sphincter surgery had normal scan results on the repeat study. Hepatobiliary imaging appears useful for diagnosis of sphincter of Oddi stenosis in selected patients in whom manometry cannot be performed and for objective assessment of response to therapy.

Subintimal dissection of peritoneovenous shunt tubing. Demonstration with radionuclide study.

A case report is presented in which malfunction of a peritoneovenous shunt was caused by subintimal dissection of the venous end of the shunt tubing. The radionuclide shunt patency study demonstrated a collection of radioactivity at the venous end of the tubing, representing the abnormal intramural collection of peritoneal fluid. Scintigraphic demonstration of this complication of a peritoneovenous shunt has not been reported previously.

Splenic variant simulating suprarenal mass diagnosed with emission computerized tomography.

The CT scans of a woman with left flank and lower abdominal pain were interpreted as showing a mass adjacent to the tail of the pancreas. Imaging with Tc-99m sulfur colloid and emission computerized tomography revealed that the CT scan abnormality represented functioning splenic tissue and thereby avoided unnecessary surgical exploration.

Thyroid nodules: sonographic-pathologic correlation.

Sonographic patterns of thyroid disease were correlated with pathologic findings. Twenty-eight cadaver thyroid glands were prospectively examined with a high-resolution real-time ultrasound scanner. Ultrasound findings were correlated in detail with gross and microscopic findings. Ultrasound is very accurate in detecting architectural variation, adenomatous goiter, and solitary nodules. Ultrasound cannot distinguish benign from malignant nodules, but it can be used to measure changes in nodule size. Glandular asymmetry and multiple solid nodules must be present for confident diagnosis of adenomatous goiter; hemorrhage, necrosis, and calcific spherules may be present in varying amounts. Fibrous septae, dilated follicles, and vascular calcification are found in normal aging thyroid glands. Using these criteria, ultrasonography is very accurate in the diagnosis of adenomatous goiter.

The relationship of the eye uptake of N-isopropyl-p-[123I]iodoamphetamine to melanin production.

Eye uptake has been a potential concern with N-isopropyl-p-[123I]iodoamphetamine (I-123 IMP) because it has been observed in certain animal species. We have investigated the cause of the eye uptake and its relationship to melanin synthesis. In a 1-yr-old cynomolgus monkey, high concentration of the tracer was seen in the eyes regardless of the type of anesthesia (pentobarbital or ketamine) or the oral administration of Lugol's solution. The eye uptake at 24 hr after injection of I-123 IMP was equally high in an 8-yr-old rhesus monkey. The ratio of radioactivity in the eye of black compared with white albino mice was 10:1 at 30 min, 18:1 at 2 hr and 36:1 at 24 hr after injection of I- 123 IMP. No eye uptake above soft-tissue background was seen in five patients at 2, 24, and 48 hr after injection. I-123 IMP is avidly incorporated into melanocytes actively producing melanin, but substantially less in melanocytes where production of melanin has ceased as in the human eye.

Use of technetium-99m macroaggregated albumin to evaluate the position and condition of totally implanted venous and arterial access devices.

Technetium-99m macroaggregated albumin is used to assess the proper location and condition of a totally implanted venous and arterial access system prior to infusion therapy. The risk of drug extravasation is thus avoided. Delivery of the chemotherapeutic agents to the intended location is assured.

The use of 123I-iodoamphetamine and single-photon emission computed tomography to assess local cerebral blood flow.

N-Isopropyl 123I P-iodoamphetamine (IMP) is a radiopharmaceutical that is lipid-soluble, penetrates the normal blood-brain barrier, and has a high first-pass extraction efficiency in brain. Initial IMP distribution is proportional to local cerebral blood flow and is stable for at least 1 hr after administration. When combined with single-photon emission computed tomography (SPECT), regional activity can be quantified. Eighty-three studies were performed to aid in understanding the clinical utility of this radiotracer. In control subjects, brain activity followed expected regional perfusion patterns. Physiologic maneuvers produced altered perfusion patterns corresponding to those demonstrated by positron tomography. Perfusion abnormalities in stroke patients were visualized earlier than structural changes detected by transmission computed tomography (CT), and the area of altered IMP activity generally exceeded that suggested by standard CT examination. Seizure foci were identified by local abnormalities of cerebral blood flow. Primary brain tumors failed to demonstrate IMP activity even when shown by angiography to be highly vascular.

Single-photon emission computed tomography. A method of measuring cerebral blood flow in three dimensions (preliminary results of studies in patients with epilepsy and stroke).

The recent development of single-photon emitting radiopharmaceuticals that reflect cerebral blood flow has introduced a new era for the useful application of nuclear medicine to the investigation of neurological disease. Using 123I labelled N-isopropyl-p-iodoamphetamine, we have performed emission-computed tomographic scans of the brain in several clinical settings. These studies display cross-sectional maps of cerebral blood flow and promise significant clinical utility in a variety of brain diseases. In the eight patients with epilepsy, the scans showed good localization of the abnormal foci, and correlated well with the findings at operation in the five patients who were submitted to surgery. All 10 patients with stroke had abnormal scans, and the abnormalities in cerebral blood flow were frequently more extensive than the lesions seen on the transmission-computed tomographic scan. This initial experience leads us to anticipate an increasing role in clinical neurology for single-photon emission computed tomographic scans of cerebral blood flow.

Comparison of N-isopropyl (I-123) p-iodoamphetamine brain scans using Anger camera scintigraphy and single-photon emission tomography.

N-isopropyl (I-123) p-iodoamphetamine (IMP), which is extracted by the brain in proportion to regional blood flow, has been shown to be useful with single-photon emission tomography (SPECT) in the assessment of pathologic states related to blood flow. Because emission tomographic equipment is not yet available at most hospitals, the authors compared IMP brain images obtained with an Anger camera with those obtained by SPECT to determine the usefulness of IMP scintigraphy. Thirty-nine pairs of studies were performed on 12 control patients, 14 patients with stroke, three patients with tumors, and a miscellaneous group of eight patients. Planar scintigraphy showed good correlation with SPECT in determining the presence or absence of abnormality in all patients except one with a very small brain stem infarction that was not detected by planar imaging. Anger images showed poor contrast resolution compared with SPECT images. It is thus expected that SPECT will result in better lesion detection when smaller lesions are studied. Planar scintigraphy is not capable of providing quantitative measurement of regional cerebral blood flow.

N-isopropyl(I-123)p-iodoamphetamine brain scans with single-photon emission tomography: discordance with transmission computed tomography.

Transmission computed tomography (CT) brain scans were compared with N-isopropyl (I-123)-p-iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) brain scans to determine if there was a correlation between morphology, as seen on CT, and cerebral perfusion changes detected by IMP SPECT. In 12 patients with acute stroke, four showed no discordance between the edema seen on CT and perfusion deficits seen on IMP SPECT; five had positive IMP scans while initial CT scans were negative and follow-up CT scans demonstrated edema in the region of perfusion deficit seen on the IMP scans; and in four patients, the average perfusion deficit was 2.3 times greater than the edema shown on CT at 2 cm above the canthal-meatal line. In nine control patients, there was a 2.3% difference in IMP activity between the right and left hemispheres. The 12 stroke patients showed 30.3% less IMP activity in the abnormal hemisphere compared with the normal side. Three patients, one with temporal lobe seizure, one with hemiballismus, and the third with idiopathic intention tumor, had 54% greater IMP activity on the side of movement or seizure than on the normal side. The discordance between IMP and CT scans was clearly demonstrated in cases in which CT showed no abnormality but IMP provided information on function, reflected in increased or decreased cerebral perfusion.

Initial experience with SPECT (single-photon computerized tomography) of the brain using N-isopropyl I-123 p-iodoamphetamine: concise communication.

Forty-six patients were studied with N-isopropyl I-123 p-iodoamphetamine (IMP) and the Harvard Scanning Multidetector Brain System. In nine control patients, good differentiation between the gray and white matter of the cerebral cortex and the basal ganglia was evident. Regional uptake was affected by physiologic maneuvers (visual stimulation). In 24 patients studied for stroke, IMP images demonstrated areas that were involved in acute infarction in eight patients whose initial transmission computerized tomography (TCT) was normal; IMP also showed perfusion abnormalities larger than the TCT abnormality in ten patients. Perfusion abnormalities were present in 23/24 of these patients. Seven patients studied with a history of TIA had normal TCT and IMP images. In three patients studied during seizure activity, regions of hyperperfusion corresponded to the EEG seizure focus. Markedly decreased activity was present in three patients with brain tumor and corresponded to the focal abnormality on the TCT study. Our study demonstrates the feasibility of assessing regional brain perfusion using a radiopharmaceutical that is lipid soluble and has a high extraction fraction in the brain, together with single-photon ECT.

Gallium-67-citrate scintigraphy in ulcerative colitis.

Gallium-67-citrate scanning was performed in 9 patients with ulcerative colitis. In all patients there was good correlation between the regional uptake of gallium and the extent and activity of disease. In 2 patients the scans were positive during an acute exacerbation and reverted to normal or near normal during clinical remission. In one patient in whom the colon was resected because of toxic dilatation, good correlation was found between pathologic and scintigraphic examinations. During the acute attack of ulcerative colitis, when colonoscopy or barium enema may be contraindicated, gallium scanning may be a noninvasive means of assessing the extent of colonic involvement. It may also be an alternative means of following the clinical course of the disease.

Observations on the clinical value of emission tomography.

Data comparing emission computed tomography (ECT), transmission computed tomography (TCT), and radionuclide scintigraphy suggest that in many patients more accurate diagnostic information may be available from emission tomography. ECT was performed during a 4-mo period on 200 of 235 patients referred for brain scans. The data suggest that ECT has a 10% greater sensitivity than scintigraphy, and better specificity. The accuracy of ECT was comparable to that of TCT performed in this group of patients. Selected cases demonstrate areas in which ECT improved lesion detection.