Scintigraphic evaluation of renovascular hypertension

ACE inhibitor challenged renal scintigraphic studies offer noninvasive means of evaluating patients for renovascular hypertension, and provide help in selecting patients who will benefit most from interventional procedures designed for alleviation of renal artery stenosis. These studies provide functional assessment of each kidney which also helps the vascular surgeons to plan which renal artery to repair first, when bilateral renal arteries are stenotic, prior to an abdominal aortic aneurysm repair. Vasotec challenged Tc99mMAG3 renal scintigraphy is one of such tests with several advantages over other similar methods, and appears to have a great potential of being a preferred scintigraphic study for evaluation of renovascular hypertension.

Changes in spectral indices of heart rate variability during exercise in acute myocardial infarction

Physical exertions are related to sudden cardiac death following acute myocardial infarction (AMI). Abnormalities in the autonomic modulation during exercise were noted in animals with AMI that were susceptible to potentially lethal arrhythmias. This study was done to evaluate the changes in the autonomic activity during exercise and recovery in AMI patients with good exercise capacity, using spectral analysis of R-R intervals of electrocardiogram (ECG). Symptom-limited treadmill exercise test was done on 17 patients of AMI with mild heart failure (in 7-10 days after the attack) and 21 healthy controls. The exercise was divided into 7 stages; rest, early exercise, mid-exercise, peak exercise, early recovery, mid-recovery, and late recovery. Power spectral analysis of R-R intervals of ECG was performed for each stage. Low frequency (0.04-0.15 Hz) and high frequency (0.15-0.40 Hz) powers, and their ratio were obtained. These parameters were observed throughout the stages in both groups. The trend of their changes during exercise and recovery was essentially the same for both groups; high and low frequency powers progressively decreased during exercise and abruptly increased during early recovery, but did not return to the values at those of rest until 9 minutes into the recovery. When the parameters were compared between the groups, there was a significantly greater decrease of high frequency power during the early exercise (p < 0.05), and a higher ratio of low to high frequency power during the early recovery (p < 0.05) in the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective study of magnetic resonance imaging and SPECT bone scans in renal allograft recipients: evidence for a self-limited subclinical abnormality of the hip

We recently reported that typical abnormalities of avascular necrosis (AVN) in magnetic resonance images (MRI) of the hips of asymptomatic renal transplant recipients whose plain radiographs are normal may improve spontaneously and even disappear completely. We present the results of serial bone scans, most of which were performed with single-photon emission computed tomography obtained over periods as long as 24 mo after transplantation in 72 of these patients. Three paired imaging studies (i.e., MR and bone scan performed within 30 days of each other) were available for each of these patients. In three patients, both the MR images and the bone scans showed changes consistent with bilateral AVN within 4 mo after transplantation. All three patients developed hip pain which was bilateral in two and unilateral in one. Two patients (three hips) required surgical intervention at which time AVN was found on pathologic examination of all three hips. None of the remaining 69 patients developed hip pain during the study. However, in nine patients whose MR studies were consistently normal, at least one bone scan was abnormal (13 hips). The presence of AVN was pathologically confirmed in each of the hips subjected to surgery. Where the imaging findings were identical to those in the asymptomatic patients as well as those in whom the imaging abnormality regressed, we suggest that the subclinical imaging abnormalities represent mild AVN, which is reversible in some cases. Since the process was identified in 10 hips by MRI and in 13 hips by bone scan, both studies are needed to detect subclinical AVN. This may be important if treatment of subclinical disease is clearly shown to prevent progression to symptomatic AVN.

The value of SPECT-thallium scanning in screening for myocardial contusion

In this prospective study of 40 patients sustaining blunt chest trauma, the value of single-photon-emission computed tomography (SPECT)-thallium scanning in the prediction of morbidity due to cardiac contusion was examined. Twelve patients developed cardiac complications--arrhythmias, ventricular conduction defects, and pericarditis. The sensitivity of SPECT-thallium scans was 55.6%, and the specificity was 32.1%, with an accuracy of 37.8%. Accuracy of the initial electrocardiogram (ECG) was 85%, with a sensitivity of 91.7% and a specificity of 82.1%. Patients with a normal ECG on admission rarely developed cardiac complications. It is concluded that SPECT-thallium is not a useful screening tool in this patient population.

HIPDM-SPECT brain imaging in the presurgical evaluation of patients with intractable seizures

We report the results of interictal and ictal HIPDM-SPECT brain imaging in 34 patients who eventually underwent temporal lobectomy for treatment of medically intractable complex partial seizures. Interictal studies revealed decreased regional cerebral perfusion (rCP) in the temporal lobe corresponding to the eventual site of surgery in 73% of the patients. Similarly, ictal study demonstrated increased rCP in 93% of the patients. In 69% of the patients, the SPECT studies were able to demonstrate both increased rCP on the ictal scan and decreased rCP on the interictal scan in the same location, corresponding to the eventual site of surgery. These results suggest that interictal and ictal SPECT brain imaging can be easily obtained and provide reliable localizing information in the presurgical evaluation of patients with medically intractable epilepsy.

Combined bone scintigraphy and indium-111 leukocyte scans in neuropathic foot disease

It is difficult to diagnose osteomyelitis in the presence of neurotrophic osteoarthropathy. We performed combined [99mTc]MDP bone scans and indium-111 (111In) leukocyte studies on 35 patients who had radiographic evidence of neuropathic foot disease and clinically suspected osteomyelitis. The [111In]leukocyte study determined if there was an infection and the bone scan provided the anatomic landmarks so that the infection could be localized to the bone or the adjacent soft tissue. Seventeen patients had osteomyelitis and all showed increased [111In]leukocyte activity localized to the bone, giving a sensitivity of 100%. Among the 18 patients without osteomyelitis, eight had no accumulation of [111In]leukocytes, seven had the [111In]leukocyte activity correctly localized to the soft tissue, two had [111In]leukocyte activity mistakenly attributed to the bone, and one had [111In]leukocyte accumulation in a proven neuroma which was mistakenly attributed to bone. These three false-positive results for osteomyelitis reduced the specificity to 83%. Considering only the 27 patients with a positive [111In]leukocyte study, the combined bone scan and [111In]leukocyte study correctly localized the infection to the soft tissues or bone in 89%. Uninfected neurotrophic osteoarthropathy does not accumulate [111In]leukocytes. We found the combined bone scan and [111In] leukocyte study useful for the detection and localization of infection to soft tissue or bone in patients with neuropathic foot disease.

HIPDM-SPECT in patients with medically intractable complex partial seizures. Ictal study

Both interictal and ictal N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3,propanediamine -single photon emission computed tomography (HIPDM-SPECT) were performed in 16 patients with medically intractable complex partial seizures. Ictal HIPDM-SPECT localized epileptic foci in 13 of 14 patients with unilateral temporal focus and provided confirmative evidence of epileptic focus in 11 patients by demonstrating maximally increased regional cerebral perfusion (rCP) in epileptic foci that had shown decreased rCP in a previous interictal study. Ictal HIPDM-SPECT in two patients with bitemporal foci showed more complicated patterns consisting of slightly increased rCP in bilateral multifocal regions. Ictal HIPDM-SPECT was particularly useful for investigating epileptic foci, and correlation with simultaneously recorded ictal electroencephalograms provided further insight for localizing epileptic foci.

Early scintigraphic findings of occult femoral and tibial fractures in infants

Differentiation of occult skeletal injuries from early acute osteomyelitis in infants and young children is important clinically. The Tc-99m MDP scintigraphic findings in six patients who had occult femoral or tibial fractures were reviewed. The images obtained early (at 1-4 days from the onset of symptoms) shared the common characteristic finding of a subtle but definite, generalized increased uptake of the tracer along the entire length of the injured bone. This pattern of uptake was similar regardless of the type of fracture. These were different from the focal abnormalities that have been observed in early acute osteomyelitis. In the absence of an extensive cellulitis or a vascular occlusive disease, a bone image showing a mild diffuse uniform increased uptake along the entire length of the tibia or femur in infants and young children with lower extremity pain of less than 1 week's duration should suggest the diagnosis of occult skeletal fractures.

Comparison of purified indium-111 granulocytes and indium-111 mixed leukocytes for imaging of infections

Several methods have been proposed for the separation and labeling of white blood cells for the diagnosis of suspected infection. We retrospectively compared 105 patients imaged with 111In purified granulocytes (GRAN) to 106 patients imaged with 111In mixed leukocytes (MIX). We found that in acute infection the sensitivity of GRAN and MIX were both high and not statistically different. In chronic infections the sensitivities were lower than for acute infections. Again, there was no significant difference between GRAN and MIX with the borderline significant exception of MIX being superior to GRAN in chronic soft tissue infections (p = 0.06). We then had independent observers blindly grade the degree of lesion visualization. We found that delayed images visualized the lesions better than early images (p = 0.0001) and acute infection was better visualized than chronic infection (p = 0.03). We concluded that, in routine clinical practice, MIX is probably the agent of choice for three reasons: (a) easier preparation, (b) comparable sensitivity in acute infection and, (c) borderline superior sensitivity in chronic infection.

Improved prediction of thyroid lobar mass from parameters obtained by routine thyroid scintigraphy

Estimation of thyroid mass both from parameters derived from thyroid scintigraphy and clinical palpation for purposes of therapeutic dosimetry has not been tested for accuracy. To more precisely determine thyroid mass 90 thyroid lobes from 45 autopsies without history of thyroid disease were studied. Specimens were dissected free of nonthyroidal tissue and assessed for volume, maximum depth (D), width (W), length (L) and mass (M). Using a linear regression model and applying known lobar depth, the most accurate formula to predict true lobar mass (in grams) was 4.9D + 0.07L2W-2.3 (in cms). Length and width would be obtainable in vivo from routine scintigraphic measurements (in cm) and depth would be most accurately determined by ultrasound. For most clinical circumstances where lobar depth is unknown we found the best formula for mass (g) to be 0.1L2W (in cm).

I-123 HIPDM SPECT imaging and cerebral angiography for EC-IC bypass evaluation

The use of SPECT in conjunction with I-123 HIPDM is a promising scintigraphic approach to the assessment of regional cerebral tissue perfusion.

Efficacy of thyroid scintigraphy in the diagnosis of intrathoracic goiter

For evaluation of the usefulness of thyroid scintigraphy in the diagnosis of intrathoracic goiter, we analyzed the results of radionuclide thyroid scintigraphy in 54 consecutive cases with suspected upper mediastinal masses. Intrathoracic goiters were found in 42. The sensitivity, specificity, and accuracy of the scintigraphy for intrathoracic goiter were 93% (39/42), 100% (12/12), and 94% (51/54), respectively. Scintigraphic morphology, scanning technique, and pitfalls are discussed. The results show that most intrathoracic goiters do have thyroid function and that radioiodine scintigraphy is a definitive and cost-effective diagnostic procedure for this disease.

Detection of acute gastrointestinal bleeding by intra-arterial Tc-99m sulfur colloid scintigraphy in a canine model. Preliminary study

The diagnostic sensitivities of arteriography, intravenous (IV) Tc-99m sulfur colloid scintigraphy, and intra-arterial (IA) Tc-99m sulfur colloid scintigraphy were evaluated in a canine model of gastrointestinal bleeding. Fifteen dogs were studied at bleeding rates ranging from .4 to 1.0 ml/minute. All three studies were obtained in six of the 15 dogs. Intravenous scintigraphy was superior to angiography in two cases, inferior in three, and equal in one. No significant difference could be shown between these two tests at these bleeding rates. Intra-arterial scintigraphy was superior to angiography in four cases and equal in two (P = .06). It was superior to IV scintigraphy in five cases and inferior in one (P = .10). In this small preliminary study, IA scintigraphy appears to be superior to the other two modalities and may prove useful in the detection of acute bleeding at the time of negative arteriography, and in serial studies in patients receiving Pitressin.

Single photon emission computed tomography (SPECT) brain imaging using N,N,N'-trimethyl-N'-(2 hydroxy-3-methyl-5-123I-iodobenzyl)-1,3-propanediamine 2 HCl (HIPDM): intractable complex partial seizures

HIPDM-SPECT brain imaging was performed in four patients with intractable complex partial seizures (CPS). Three patients had an epileptogenic focus in one temporal lobe and underwent anterior temporal lobectomy. Interictal HIPDM-SPECT demonstrated decreased regional cerebral perfusion (rCP) in the epileptogenic area in only one patient, but ictal studies showed increased rCP in the epileptic foci of all three patients. In the fourth patient, interictal HIPDM-SPECT showed increased rCP in the area of epileptogenic focus; when antiepileptic medication was taken, rCP decreased. HIPDM-SPECT brain imaging is useful for localizing epileptogenic foci in CPS.

Clinical comparison of indium-111 acetylacetone and indium-111 tropolone granulocytes

This clinical study compares the efficacy of two 111In white blood cells preparations. Seventy-six patients were imaged after an injection of granulocytes (GRAN) isolated on a Ficoll-Hypaque gradient and labeled with [111In]acetylacetone (ACAC) in saline; 105 patients were imaged after an injection of GRAN isolated on a metrizamide-plasma gradient and labeled with [111In]tropolone (TROP) in plasma. Early (2-4 hr), intermediate (4-6 hr), and delayed (24 hr) images were obtained. The specificity was quite high (94-100%) in both preparations and no statistical differences could be found. The sensitivity for ACAC-GRAN for the early, intermediate, and delayed images were 39%, 63%, and 64%, respectively; for TROP-GRAN it was 80%, 89%, and 92%, respectively. In all cases the TROP-GRAN images were significantly more sensitive than the ACAC-GRAN images obtained at the same time after injection (p less than 0.001 for early and delayed images, 0.01 less than p less than 0.025 for intermediate images). For ACAC-GRAN the intermediate and delayed images were significantly more sensitive than the early images, while no significant difference could be found for TROP-GRAN. In a blinded experiment, the ability of TROP-GRAN to demonstrate a lesion was compared to that of ACAC-GRAN. TROP-GRAN demonstrated the lesions better than ACAC-GRAN, both in the early and late images (p less than 0.001). TROP-GRAN visualization scores at 4-6 hr equaled those obtained 24 hr after injection. In conclusion, GRAN separated and labeled in plasma with TROP are superior to those separated and labeled in saline with ACAC in three ways: higher visualization scores, earlier visualization of the lesion, and greater sensitivity.

Pulmonary imaging in fat embolism syndrome

Ventilation/perfusion lung scanning can be used to effectively detect fat embolism following skeletal trauma. Typical ventilation/perfusion findings may be present when the chest radiograph is normal, and clinical findings are equivocal.

Spurious thyroid cancer metastasis: saliva contamination artifact in high dose iodine-131 metastases survey

The use of high dose 131I for workup of thyroid cancer patients increases the chance of contamination artifact which may mimic metastases. Two elderly male patients with follicular carcinoma of the thyroid had salivary contamination artifacts on metastatic survey scans. These patients received a 1 and 10 mCi dose of 131I, respectively. The artifacts were recognized only retrospectively when follow-up scans were obtained and compared. The characteristics of contamination artifacts and several methods to confirm these are discussed.

Short-term in vivo stability of endothelial-lined polyester elastomer and polytetrafluoroethylene grafts

A fibronectin substrate will significantly enhance the strength of endothelial cell attachment on grafts constructed of polyester elastomer (PE) and polytetrafluoroethylene (e-PTFE). This experiment was undertaken to determine the short-term in vivo stability of endothelium on these fibronectin coated surfaces. Eight mongrel dogs underwent bilateral carotid artery replacement with both graft materials. All grafts were inoculated with 2,000 cells/mm2 using cultured autogenous venous endothelium labelled with Indium-111-oxine. The Indium-111 label in the grafts was measured immediately prior to implantation, after 1 hour of in vivo perfusion, and at explantation after 24 hours. The percentage of inoculated cells attached to the grafts before perfusion was similar for both materials, 93.3 +/- 3.0% versus 92.2 +/- 7.2%, for PE and e-PTFE respectively. All grafts were patent at one hour after implantation. PE grafts were found to have 93.8 +/- 3.9% of the attached cells present at one hour while e-PTFE grafts had only 54.5 +/- 10.8% remaining, p less than .001. After 24 hours, 5/8 (62.5%) e-PTFE grafts and 2/8 (25.0%) PE grafts remained patent, p = .13. Of the patent grafts however, endothelial cell retention was still superior on the PE grafts with 78.0 +/- 0.6% of the attached cells remaining compared to only 24.5 +/- 6.1% on e-PTFE, p less than .001. Occluded PE grafts had fewer cells remaining at 24 hours than patent ones, 78.0 +/- 0.6% versus 31.1 +/- 32.8%, respectively, p = .13. Histologically, patent PE grafts demonstrated nearly confluent endothelial monolayers while e-PTFE had patches of endothelial cells surrounded by a platelet-fibrin carpet.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhanced strength of endothelial attachment on polyester elastomer and polytetrafluoroethylene graft surfaces with fibronectin substrate

Successful development of a vascular prosthesis lined with endothelium may depend on the ability of the attached cells to resist shear forces after implantation. The purpose of this article is to describe a model for measurement of endothelial detachment caused by shear stress and to identify biomaterials that resist loss of attached cells as a result of shear stress. With human umbilical venous endothelium labeled with indium 111-oxine, cellular attachment to uncoated and fibronectin-coated polyester elastomer and expanded polytetrafluoroethylene (e-PTFE) graft surfaces was quantified after an 18-hour incubation. PTFE grafts prepared by immediate seeding were also studied. The relative strength of endothelial attachment was determined by the percentage of the original inoculum remaining after the seeded graft surfaces were subjected to a physiologic shear stress of 15 dynes/cm2 during in vitro perfusion. In polyester elastomer grafts, fibronectin did not significantly increase initial attachment but did increase the percentage of inoculum remaining after perfusion (92.1% vs. 39.74%, p = 0.001). A similar relationship existed between fibronectin-coated e-PTFE and immediately seeded e-PTFE preparations with 61.6% and 25.8%, respectively, of the inoculum remaining after perfusion (p = 0.001). Furthermore, the percentage of inoculum retained on fibronectin-coated polyester elastomer was significantly greater than on fibronectin-coated e-PTFE (p = 0.001). In comparing uncoated grafts, polyester elastomer had 39.7% of the inoculum retained after perfusion whereas only 1.8% was remaining on the e-PTFE grafts (p = 0.0001). We conclude that polyester elastomer permits better endothelial cell attachment than e-PTFE and that fibronectin coating enhances the strength of attachment to both graft materials.

Portal hypertension due to jejunal vascular malformation

We report a case of hepatic portal venous hypertension secondary to a small-bowel vascular malformation in a 24-year-old man with anemia. Preoperative diagnostic evaluation included gastrointestinal barium studies and endoscopy (showing esophageal varices), hepatic panangiography, peroral small-bowel biopsy, percutaneous transhepatic portal venography, and manometry. Preoperative injection of methylene blue dye into the jejunal arteries supplying the malformation resulted in easy localization of the lesion at surgery. Direct manometry at the time of segmental jejunal resection yielded a portal pressure of 35 mmHg, with subsequent reduction to 21 mmHg.

Scintigraphic evaluation of extremity pain in children: its efficacy and pitfalls

Early detection of an inflammatory process involving bone and joints is very important in children with extremity pain. We reviewed the efficacy and pitfalls of three-phase bone scans in 100 consecutive children with acute extremity pain. Sixty-one of the subjects showed abnormalities on bone scans. The sensitivity and specificity of three-phase bone scans for acute osteomyelitis were 84% and 97%, respectively. Sensitivity and specificity for both acute septic joint and cellulitis were 93% and 100%, respectively. Pitfalls in interpretation of three-phase bone scans include simulation of infection by fracture and obscuration of osteomyelitis by septic arthritis, prior antibiotic treatment, and the occasional "cold" defect due to ischemia.

Scintigraphic dissociation of reticuloendothelial and hepatocyte function in chronic vitamin A hepatotoxicity

A discordant hepatic uptake between Tc-99m sulfur colloid and Ga-67 citrate has occurred in an adult patient with hepatotoxicity due to hypervitaminosis A. The authors believe this is a scintigraphic phenomenon related to the characteristics of the radiopharmaceuticals used and does not necessarily represent a true dissociation of various cellular functions of the liver.

Transcatheter brush biopsy of a liver mass with CT-proven intracaval extension

We report the adjunctive use of CT scanning in confirming the intraluminal location of an intracaval mass prior to transcatheter brush biopsy. In addition, we review several important reports of transcatheter biopsies in both the IVC and SVC, and cite potential complications.

Parallax error in pinhole thyroid scintigraphy: a critical consideration in the evaluation of substernal goiters

Parallax error is found to be another pitfall in pinhole thyroid scintigraphy, i.e., a substernal goiter may appear between the thyroid cartilage marker and the suprasternal notch marker. Unless one is aware of this pitfall, a substernal extension of the thyroid may not be realized or be seriously underestimated in its size and extent. We illustrated the parallax error using a thyroid phantom. An illustrative case is shown.

Evaluation of complicating osteomyelitis with Tc-99m MDP, In-111 granulocytes, and Ga-67 citrate

Studies with gallium-67 and three-phase bone imaging (TPBS), though very sensitive, are not very specific in evaluating suspected osteomyelitis (OM) that is superimposed upon other diseases causing increased bone turnover. A total of 57 patients with suspected OM were studied; this included 48 with increased bone turnover. All of the patients were studied with granulocytes labeled with In-111 acetylacetone (In-111 GRAN), TPBS and 29 of these patients had Ga-67 studies as well. In-111 GRAN had a sensitivity of 100% in acute OM and 60% in chronic OM, with a specificity of 96%. Gallium-67 was excellent in ruling out OM when the study was normal, or in ruling in OM when the relative uptake of Ga-67 exceeded the uptake of Tc-99m MDP, or when the Ga-67 in bone had a different distribution from the TPBS. Unfortunately, these criteria were met in only 28% of our subjects. We conclude that when added to TPBS, the In-111 GRAN study plays an important role in detecting complicating OM.

Gastric emptying of enteric-coated tablets

To evaluate the gastric emptying time of pharmaceutical dosage forms in a clinical setting, a relatively simple dual-radionuclide technique was developed. Placebo tablets of six different combinations of shape and size were labeled with indium-111 DTPA and enteric coated. Six volunteers participated in a single-blind and crossover study. Tablets were given in the morning of a fasting stomach with 6 oz of water containing 99mTc pertechnetate and continuously observed with a gamma camera. A scintigraph was obtained each minute. The results suggested that the size, shape, or volume of the tablet used in this study had no significant effect in the rate of gastric emptying. The tablets emptied erratically and unpredictably, depending upon their time of arrival in the stomach in relation to the occurrence of interdigestive myoelectric contractions. The method described is a relatively simple and accurate technique to allow one to follow the gastric emptying of tablets.

Anomalous drainage of the right superior vena cava into the left atrium

A 22 year old man with asymptomatic hypoxemia was found to have a large right to left shunt due to a rare congenital anomaly: total drainage of the right superior vena cava into the left atrium. The anomaly was first suspected after radionuclide angiocardiography was performed using technetium-99m macroaggregated albumin and was confirmed by cardiac catheterization. Contrast echocardiographic and surgical findings are discussed. Other reports on this anomaly are reviewed.

Pitfalls of cholescintigraphy. A case report

A Tc-99m PIPIDA scan was performed in a young auto accident victim who had a transient rise in serum bilirubin level. Initially, the stasis of activity in the right ureter was mistaken for activity in the common bile duct. Misinterpretation of biliary imaging studies can be prevented with awareness of pitfalls and readiness to obtain delayed images and additional images in different projections.

Tc-99m diphosphonate imaging in the differential diagnosis of thyroid nodules

Early Tc-99m diphosphonate (DP) imaging was performed in 122 patients with cold thyroid nodules in an effort to differentiate benign nodules from malignant. Immediately upon completion of the routine 24-hour I-123 uptake and multiview pinhole imaging, Tc-99m DP was injected intravenously and three serial 3-minute anterior images of the thyroid gland were obtained. Follow-up information was available in 85 patients. All cystic lesions had less Tc-99m uptake as compared with the uptake in the normal parts of the thyroid. However, 48 of 50 solid nodules had Tc-99m DP uptake to the same or greater degree than did the normal gland. The other two had mixed pattern on ultrasound examination. Most of the carcinomas (8 of 10) and benign adenomas (15 of 22) had identical appearance on Tc-99m scans, i.e., uptake in the lesion being the same as in the normal thyroid. It appears that by using this technique it is possible to separate solid nodules from cystic, but not benign from malignant.

Scintigraphic evaluation of diabetic osteomyelitis: concise communication

We have reviewed the three-phase bone scans, radiographs, and histologic findings of 39 diabetic patients with serious foot problems. The sensitivity and specificity of bone scans were 83% and 75%, respectively, for osteomyelitis of the small bones of the foot. The positive and negative predictive values were 87% and 69%, respectively. The radiographs were less sensitive (62%) and less specific (69%), with predictive values of 80% (positive) and 47% (negative).

High-contrast film copying for thallium 201 cardiac image processing

To evaluate the usefulness of high-contrast film copying as an economical means of enhancing contrast in thallium 201 cardiac images, stress and rest studies of 47 patients with and 19 patients without coronary artery disease were evaluated. A total of 66 sets of four different image formats were independently interpreted by five observers. The analysis of the receiver operating characteristic curves suggested that the high-contrast film copies were superior to their original analog images and comparable with computer-processed images in diagnostic yield. It appears that contrast enhancement by simple film copying can improve the accuracy of 201Tl image interpretation.

A comparative study of serum lipids between Belgium and Korea

Serum cholesterol values are markedly lower in Korea than in Belgium in both males and females. This is attributed to the much lower consumption of saturated fat in Korea. A mean population serum cholesterol value of about 160 mg/dl appears to be compatible with excellent general health and with the absence of ischemic heart disease or other atheromatous diseases. The influence of age, height and weight on cholesterol between Belgium and Korea is qualitatively similar but quantitatively different. High-density lipoprotein cholesterol values are lower in Korea than in Belgium, particularly in females. Differences in the HDL cholesterol level thus cannot explain the low prevalence of ischemic heart disease in Korea.

Efficacy of noninvasive modalities of diagnosis of thrombophlebitis

In a blind prospective study of 158 limbs, Doppler ultrasound, pneumoplethysmography, and radionuclide venography (RNV) using 99mTc-MAA were compared to phlebography as methods of detecting thrombophlebitis. All three noninvasive modalities were very insensitive to isolated thrombus below the knee. In patients with extension of thrombus above the knee and isolated thrombus in the deep veins of the upper limb, Doppler ultrasound had a sensitivity of 81% and RNV had a sensitivity of 77%. All of the noninvasive modalities were found to be dependent on venous occlusion. Overall, pneumoplethysmography had a sensitivity of 28% and specificity of 96%, compared with 56% and 91%, respectively, for Doppler ultrasound and 51% and 84% for RNV. Based on these findings, phlebography would still seem to be the modality of choice in the diagnosis of thrombophlebitis.

Pulmonary scintigraphy in fibrosing mediastinitis due to histoplasmosis

The pulmonary scintigraphic findings from four patients with fibrosing mediastinitis due to histoplasmosis are reported. The ventilation/perfusion (V/Q) mismatch mimicked pulmonary emboli. However, in these cases the chest radiographs and/or gallium-67 scintigraphy were abnormal, suggesting mediastinal or hilar disease. Awareness of the nonembolic conditions that can result in V/Q mismatches is important in the interpretation of lung scans.

Feasibility of low doses of I-131 for thyroid ablation in postsurgical patients with thyroid carcinoma

The feasibility of using low doses of I-131 (30 mCi) for ablation of thyroid remnants following surgery for papillary and follicular thyroid carcinoma was examined in 21 patients. Six weeks following near-total thyroidectomy and three days following intramuscular thyroid-stimulating hormone (10 IU), patients were given 30 mCi of I-131 and scans were performed 24 to 72 hours later. Remaining thyroid tissue was identifiable in the thyroid bed in 19 patients, and two patients also had evidence of cervical metastases. Patients with metastases received an additional 100 mCi of I-131. Follow-up I-131 scans were performed at nine to 15-month intervals in ten patients who initially received 30 mCi of I-131, and only one patient showed complete ablation of the residual thyroid tissue, whereas the remaining nine patients had persistent uptake of I-131 in the same regions in which the uptake was seen in the initial postoperative scans. One of the nine patients had evidence of a cervical metastasis as well. It is therefore apparent that total or near-total thyroidectomy rarely removes all thyroid tissue and that an "out-patient" dose of I-131 is not adequate for ablation of postoperative thyroid remnants.

Quantitation of ischemic injury with 99mTc-HEDP in experimental acute tubular necrosis

Incremental ischemic injury was induced in rabbits by transient occlusion of the renal artery. Renal localization of 99mTc-HEDP was quantitated in ischemic and normal kidneys at fixed intervals following restoration of blood flow. Creatinine clearance and microscopic evaluation of renal structure were determined concurrently with scintigraphic studies. There was a sequential reduction in creatinine clearance and an increase in tubular necrosis with prolongation of the ischemic period. 99mTc-HEDP localization in ischemic renal tissue was dependent on the degree of renal injury, ranging from twice normal with minor injury to a nine-fold increase with the most severe ischemic changes. The increased accumulation was demonstrable for longer periods with increasing ischemic injury. Considerable recovery of renal function was apparent in all groups by one week. 99mTc-HEDP may be useful in evaluation of renal failure secondary to ischemic injury.