"Allergic sinusitis" revisited.

BACKGROUND: "Allergic sinusitis" is a frequently used term but there is question about its true existence. OBJECTIVE: To detect the presence of allergic inflammation of the sinuses in five highly symptomatic ragweed sensitive adults. METHOD: Three imaging techniques were utilized: SPECT bone imaging, SPECT Indium111 labeled WBC uptake, and FDG F-18 (PET scanning). RESULTS: We could find no evidence of sinus involvement in association with severe allergic rhinitis. CONCLUSIONS: Employing three different imaging modalities, we were unable to demonstrate inflammation of the sinuses in patients with allergic rhinitis.

Delayed recovery of thyrotropin responsiveness after radioactive iodine therapy for hyperthyroidism.

BACKGROUND: After radioactive iodine therapy for hyperthyroidism, an expected lag in the responsiveness of thyrotropin (TSH) is 60 to 90 days. In our experience, however, many patients seemed to have a more prolonged lag in TSH recovery. METHODS: A retrospective chart review was performed in 58 patients who underwent radioactive iodine therapy for hyperthyroidism (52 with Graves disease, 5 with toxic nodular goiters, and 1 with a toxic adenoma). RESULTS: Forty-nine patients (84%) had appropriate responses of TSH for their level of serum thyroid hormone. Thirty-one became hypothyroid, 12 became euthyroid, and 6 remained hyperthyroid. Nine patients (16%) had a lag in their TSH responsiveness. The TSH remained low for 3 months in 5 patients, for 9 months in 3 patients, and 1 patient had low levels of serum TSH for at least 12 months. CONCLUSIONS: After radioactive iodine therapy for hyperthyroidism, decisions upon further therapy must be based upon the clinical status as well as the serum levels of TSH and thyroid hormones.

Does inhaled pollen enter the sinus cavities?

BACKGROUND: While there is evidence of an increased incidence of sinusitis in patients with allergic rhinitis, it is unclear whether an allergic process occurs in the sinus tissues per se. OBJECTIVE: The purpose of this study was to determine whether inhaled pollen reaches the sinus mucosa. METHODS: Tc99m labeled ragweed pollen was inhaled by five non-atopic adults. Imaging studies of the sinuses were performed with a tomographic rotating gamma camera. To determine the sensitivity of the technique, the nose and the maxillary sinuses of cadaver heads were painted with varying amounts of Tc99m and then similarly scanned. RESULTS: Scans of the cadaver heads showed clear resolution between the nasal cavity and the maxillary sinus. It was determined that 20 microci was the smallest amount of Tc99m that could be resolved to be in the sinuses. Scans of subjects showed intense activity in the nasal cavity but none in the paranasal sinuses despite the delivery of a supraphysiologic dose of Tc99m ragweed pollen. CONCLUSION: Inhaled ragweed pollen does not appear to enter the paranasal sinuses. It is unlikely that an inhaled antigen-IgE antibody reaction occurs in the sinus mucosa.

Quantitative technetium-99M dimercaptosuccinic acid renal scanning in children.

OBJECTIVES: To develop a method for assessing absolute renal function (as well as morphology) in children, using gamma camera imaging of intravenously injected technetium-99m (99mTc) dimercaptosuccinic acid (DMSA). METHODS: Forty-five children (ages 1 week to 10 years; mean, 2.0 years) were imaged using a planar technique in which not only the appearance but the absolute amount of intravenously administered 99mTc DMSA taken up by the kidneys was calculated for each child and compared with contemporaneous determinations of creatinine clearance. RESULTS: There was a close correlation between the absolute DMSA uptake and creatinine clearance (r = 0.752). CONCLUSIONS: Renal function in children, expressed as creatinine clearance, can be accurately estimated by measuring absolute DMSA uptake with planar gamma camera imaging using 99mTc DMSA.

Right ventricular function in patients with severe COPD evaluated for lung transplantation. Lung Transplant Group.

Right ventricular function was measured in ten patients with severe COPD (mean FEV1 = 0.48 +/- 0.2 L/s) as part of an evaluation for single lung transplant (SLT). Right ventricular ejection fraction (RVEF) was determined by two methods: first-pass radionuclide scan by multigated acquisition (MUGA) and by using a fast thermistor tipped RVEF/volumetric pulmonary artery catheter. None of the patients had clinical evidence of active right heart failure, although mild resting pulmonary hypertension (mean pulmonary artery pressure [PAP] = 24 +/- 4 mm Hg) that worsened with minimal exercise (mean PAP = 39 +/- 11 mm Hg) was present. There was a significant difference in RVEF measured by the two methods (mean MUGA RVEF = 57 +/- 10%, mean catheter RVEF = 27 +/- 8%; p < 0.00005). RVEF determined by both methods was correlated with hemodynamic and gas exchange variables obtained during rest and at maximal exercise. There were significant, yet inverse, correlations between RVEF measured by catheter and cardiac index measured during exercise (CIex), as well as with exercise pulmonary vascular resistance index (PVRI). There were no significant correlations found between MUGA RVEF and any gas exchange or hemodynamic variables. Significant correlations were found with the catheter-measured right ventricular end-diastolic volume (RVEDV) and CIex (r = 0.9 p < 0.005), with maximal oxygen consumption during exercise (VO2max) (r = 0.86 p < 0.0025), with exercise stroke volume index (SVI) (r = 0.76 p < 0.01), and exercise central venous pressure (CVP) (r = 0.62 p < 0.05). Echocardiographic studies revealed right ventricular dilatation and mild tricuspid regurgitation (TR) in all patients. The strong correlation between RVEDV, CIex, and VO2max supports the concept that in these patients, as long as there is no clinical evidence of right heart failure (resting CVP still within normal limits), those with the largest RVEDVs use the Frank Starling principle to their best advantage to remain more functional.(ABSTRACT TRUNCATED AT 400 WORDS)

Pharmacokinetics and normal organ dosimetry following intraperitoneal rhenium-186-labeled monoclonal antibody.

UNLABELLED: Pharmacokinetics, biodistribution and radiation dose estimates following intraperitoneal administration of a 186Re-labeled murine antibody, NR-LU-10, were assessed in 27 patients with advanced ovarian cancer. METHODS: Quantitative gamma camera imaging and gamma counting of serum and intraperitoneal fluid radioactivity were used to obtain data for dosimetry estimation. The MIRD intraperitoneal model was used to estimate dose to normal organs from radioactivity within the peritoneal cavity. The absorbed dose to normal peritoneum was estimated in two ways: from the gamma camera activity and peritoneal fluid samples. RESULTS: Serum activity peaked at 44 hr and depended on the concentration of radioactivity in the peritoneal fluid. Mean cumulative urinary excretion of 186Re was 50% by 140 hr. Estimates of radiation absorbed dose to normal organs in rad/mCi administered (mean +/- s.d.) were whole body 0.7 +/- 0.3; marrow 0.4 +/- 0.1; liver 1.9 +/- 0.9; lungs 1.3 +/- 0.7; kidneys 0.2 +/- 0.2; intestine 0.2 +/- 0.2. Peritoneal surface dose estimates varied depending on the volume of fluid infused and the method of dose determination. Using gamma camera data, the peritoneal dose ranged from 7 to 36 rad/mCi. Using peritoneal fluid sample data, the dose ranged from 2 to 25 rad/mCi. Significant myelosuppression was observed at marrow doses above 100 rad. CONCLUSION: Noninvasive methods of dose estimation for intraperitoneal administration of radioimmunoconjugates provide reasonable estimates when compared with previously described methods.

Correlation of pharmacological 99mTc-sestamibi myocardial perfusion imaging with poststenotic coronary flow reserve in patients with angiographically intermediate coronary artery stenoses.

BACKGROUND: The physiological assessment of angiographically intermediate-severity stenoses remains problematic. Functional measurements of poststenotic intracoronary Doppler coronary flow reserve can be performed in humans but have not been correlated with hyperemic myocardial perfusion imaging or angiographic data in this patient population. METHODS AND RESULTS: Thirty-three patients undergoing diagnostic quantitative coronary angiography (QCA) for assessment of intermediate-severity coronary artery disease (mean QCA percent diameter stenosis, 56 +/- 14%) were studied. Proximal and distal poststenotic Doppler coronary flow velocities were measured (left anterior descending coronary artery, 16; right coronary artery, 10; left circumflex artery, 7 patients) before and during peak maximal hyperemia with intracoronary adenosine (8 to 12 micrograms). Intravenous pharmacological stress (adenosine, 20 patients; dipyridamole, 13 patients) 99mTc-sestamibi tomographic perfusion imaging was performed within 1 week of coronary flow-velocity studies. kappa statistics were calculated to measure the strength of correlation among coronary flow velocities, perfusion imaging data, and QCA results. QCA stenosis severity (abnormal, > or = 50% diameter stenosis) and poststenotic Doppler coronary flow reserve (ratio of abnormal distal hyperemic to basal flow, < or = 2.0) were correctly correlated in 20 of 27 patients (74%; kappa = .48). QCA stenosis severity and 99mTc-sestamibi imaging (abnormal if one or more reversible myocardial segments were present in the poststenotic zone) were correlated in 28 of 33 patients (85%; kappa = .63). 99mTc-sestamibi imaging results agreed with the basal (nonhyperemic) proximal-to-distal velocity ratio (normal, < 1.7) in 15 of 31 patients (48%; kappa = .17). The strongest correlation occurred between hyperemic distal flow-velocity ratio measurements and 99mTc-sestamibi perfusion imaging results in 24 of 27 patients (89%; kappa = .78). All 14 patients with abnormal distal hyperemic flow-velocity values had corresponding reversible 99mTc-sestamibi tomographic defects. More reversibly hypoperfused segments were present in patients with abnormal poststenotic hyperemic flow-velocity ratios (abnormal, 2.4 +/- 0.7 segments; normal, 0.6 +/- 1.0 segments; P < .05). The number of poststenotic myocardial 99mTc-sestamibi perfusion defects was correlated with the QCA percent cross-sectional area reduction (P < .02) and with minimal luminal diameter (P < .05) of intermediate-severity coronary artery stenoses. CONCLUSIONS: Two technologically diverse functional measures of stenosis severity--Doppler-derived poststenotic hyperemic intracoronary flow reserve and vasodilator stress 99mTc-sestamibi myocardial perfusion imaging--are highly (89%) correlated. The physiological assessment of coronary stenoses of angiographically intermediate severity may be improved by the use of these techniques.

Asymmetric intramyocardial lymphocytic accumulation during acute rejection in rat heart and heart-lung transplantation.

Lymphocytic accumulation in different areas of the myocardium during different phases of acute rejection were studied in rat heterotopic cardiac and cardiopulmonary allograft and isograft transplantation models. Indium 111-labeled syngeneic lymphocytes were injected 1 to 7 days after transplantation, and accumulation of the labeled cells in the graft was determined 24 hours later. The cardiac graft was divided into three segments: right ventricular (RV) free wall, epicardial portion of the left ventricle (LV) plus RV septum, and endocardial portion of the LV. In the subsequent heart-lung transplantation group, the LV epicardial portion plus RV septum segment was subdivided into LV epicardial portion and RV septum. Lymphocytic accumulation in each segment was compared between three groups according to the day the animal was killed after transplantation: days 2, 3 (group 1), days 4, 5 (group 2), and days 6, 7, 8 (group 3). Lymphocytic accumulation caused by rejection in group 1 and group 2 of both the cardiac and cardiopulmonary allografts showed significantly different intramyocardial distribution (p less than 0.01). Lymphocytic accumulation was consistently highest in RV free wall and lowest in LV endocardial portion. In group 3 specimens, lymphocytic accumulation was symmetrical in both the cardiac and cardiopulmonary allografts. In the cardiac allograft, the lymphocytic accumulation increased sharply on day 4 then declined to a nadir. This transient increase was not so pronounced in the cardiopulmonary allografts. The significantly decreased intramyocardial lymphocytic accumulation in group 2 of the cardiopulmonary allografts when compared with the cardiac allografts (p less than 0.01) is compatible with the clinical observation of a lower incidence of acute heart rejection in heart-lung transplant recipients. These data show an asymmetric accumulation of lymphocytes during acute heart rejection, which is due to increased lymphocytic affinity for the RV free wall.

Prognostic significance of exercise thallium-201 testing in patients aged greater than or equal to 70 years with known or suspected coronary artery disease.

The prognostic value of exercise thallium-201 myocardial perfusion imaging has not been studied in an elderly (aged greater than or equal to 70 years) population. Retrospective analysis of 120 consecutive elderly patients undergoing Bruce protocol exercise stress with quantitative planar thallium-201 scintigraphy, followed clinically for a mean of 36 +/- 12 months after testing, revealed a 10% cardiac event rate (6 cardiac deaths from arrhythmia or congestive heart failure, and 5 fatal and 1 nonfatal myocardial infarction). There were no exercise stress-related complications. Survival without cardiac events was associated with greater exercise duration (5.6 +/- 2.4 vs 3.1 +/- 2.4 minutes; p less than 0.0007) and peak exercise heart rate (131 +/- 18 vs 120 +/- 19 beats/min; p less than 0.05). Univariate variables associated with higher cardiac event rates included: (1) peak exercise less than or equal to stage I (18 vs 6%; p = 0.04); (2) maximal ST-segment depression greater than or equal to 2 mm (27 vs 6%; p = 0.003); and (3) presence of a fixed or reversible thallium-201 perfusion defect (18 vs 2%; p = 0.004). Multivariate stepwise logistic regression analysis identified the combination of peak exercise less than or equal to stage I and any thallium-201 perfusion defect as the most powerful predictor of subsequent cardiac events (relative risk = 5.3 at 1 year). Thus, exercise thallium-201 scintigraphy in elderly patients is safe and provides important prognostic information.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of lung rejection with indium-111-labeled lymphocytes in heterotopic rat heart-lung transplantation.

To determine if acute lung rejection after heart-lung transplantation can be detected noninvasively with indium-111-labeled (111In) lymphocytes, we studied 33 allogeneic and 18 isogeneic heterotopic heart-lung transplants in rats. Twenty-four hours after injection of isogeneic splenic 111In-lymphocytes (75 +/- 2 microCi/100 million cells), animals were scanned at 2 to 8 days after transplant (Tx). Also, percent indium uptake of the graft was determined and compared with pathologic lung changes. Between the vascular and destructive phases of lung rejection, 111In-lymphocyte uptake of lung allografts was significantly greater than isografts (p less than 0.001). Lung allografts in the alveolar phase (4-6 days after Tx) showed the most intense uptake (2.7 +/- 0.1%) of injected 111In-lymphocytes. All scintigrams of allografts from the late vascular to the early destructive phase (3-7 days after Tx) showed visualization of the lung graft (27/27 true positive, sensitivity = 100%). In contrast, lung isografts of the same period showed no pathological sign of rejection and were only rarely visualized (12/14 true negative, specificity = 86%). Lung rejection may be accurately assessed noninvasively by gamma scintigraphy with 111In-lymphocytes. This technique may prove useful in the detection of acute lung rejection in human heart-lung transplant recipients. Modification of the labeling dose chosen may further improve scan accuracy.

Ventilation/perfusion mismatch caused by emphysematous bullae.

A case of ventilation/perfusion mismatch caused by emphysematous bullae is presented. The presumed mechanism for the mismatch was vascular displacement of the pulmonary arterial tree by bullae with apparently normal ventilation. The latter may have been related to the circumferential distribution of the bullae around each lung. This entity represents an addition to the differential diagnostic list of causes of ventilation/perfusion mismatch on radionuclide lung images.

The effect of intravesical pressure on glomerular filtration rate in patients with myelomeningocele.

Numerous investigators have demonstrated the development of hydronephrosis and renal deterioration in patients with myelomeningocele who have high pressure bladders. By drawing blood at sequential intervals during 99mtechnetium-diethylenetriaminepentaacetic acid renal scanning we are able to generate nuclide clearance curves that correlate well with glomerular filtration rate. Renal scanning is done most frequently with the bladder catheterized and left to gravity drainage. By filling the bladder under manometric control to a pressure of 35 to 40 cm. water we have followed routine scanning with continued blood sampling to generate nuclide clearance at low and high bladder pressures. In 5 myelomeningocele patients so studied we found consistent and significant decreases in glomerular filtration rate at high bladder pressures.

Improved interpretation of exercise Tl-201 myocardial perfusion scintigraphy in women: characterization of breast attenuation artifacts.

Thallium-201 myocardial perfusion scintigraphy is reported to be a less accurate diagnostic test for coronary artery disease in women than in men. We retrospectively analyzed 34 Tl-201 studies obtained in 28 symptomatic women and compared them with those obtained in 32 men during the same interval. Three criteria were tested: criterion 1 was defined as abnormal scans showing any defect; criterion 2, scans showing only transient (reversible) defects; and criterion 3, scans showing either transient or "significant" (i.e., not due to breast attenuation) fixed defects. The sensitivity in women was 1.00, 0.73, and 0.93, respectively; the specificity, 0.26, 0.84, and 0.85. The best values in men were a sensitivity of 1.00 and a specificity of 0.86. The three criteria were then prospectively tested in 33 scans of 29 additional women. The sensitivity was 0.90, 0.65, and 0.80, respectively, and the specificity, 0.18, 1.00, and 0.92. Defects (usually fixed) due to breast attenuation artifact were seen frequently (30%). Criterion 3 best differentiates such defects from those resulting from coronary artery disease, making Tl-201 myocardial perfusion scintigraphy as accurate in women as in men.

Misleading findings on indium-111 leukocyte images.

In-111 leukocyte imaging usually yields images which are interpreted easily. Five potentially misleading cases were noted, however, of over 200 scans performed over a four-year period. These included two cases of bladder visualization without bladder inflammation and three cases of abdominal activity without intra-abdominal abscess or inflammatory bowel disease. Migration of leukocytes from other true pathologic sites and technical factors were responsible for the activity seen. Knowledge of all aspects of the patient's clinical status, including other diagnostic modalities performed, was critical in arriving at the correct diagnosis.

Significance of diffuse cardiac activity on In-111 labeled leucocyte scans.

To assess the significance of diffuse cardiac activity (DCA) seen on In-111 labeled leukocyte scans, we reviewed 87 studies performed over the last 4 years. Inflammatory cardiac conditions were seen as frequently in patients with DCA (15%) as those without (7%, P = 0.3). There was a higher ratio of RBC:WBC in the final WBC preparation in the false-positive DCA group than the true positive DCA and no DCA groups. False-positive studies showing DCA are most likely due to residual blood pool activity.

Scintigraphic features of giant cell tumor.

The scintigraphic appearance of giant cell tumor of bone in six patients is presented. Patients were studied by means of Tc-99m MDP bone scanning. On early blood pool and delayed imaging, markedly increased activity was noted, characteristically displaying a "ring" pattern that is readily discernible from patterns seen in bone cysts and nonosteogenic fibroma. The extent of the lesion, as judged by scintigraphic techniques, was roughly equal to estimates of extent by other radiographic modalities. Only one example of a different lesion mimicking giant cell tumor was encountered in over 100 cases of a variety of primary bone neoplasms reviewed. We conclude that giant cell tumor has a characteristic scintigraphic appearance.

Radionuclide demonstration of ventriculoatrial shunt-cutaneous fistula with cerebrospinal fluid leak.

Radionuclide techniques have commonly been used to assess ventriculovenous shunt function, cerebrospinal fluid dynamics, and for the diagnosis of cerebrospinal fluid leaks. All of these techniques were utilized in this unusual case of retrograde migration of a ventriculoatrial catheter into the neck, with cutaneous fistulization and CSF leak.