Dynamic infrared imaging of newly diagnosed malignant lymphoma compared with Gallium-67 and Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography.

Staging and therapy monitoring of malignant lymphomas relies heavily on imaging using arbitrary size criteria from computed tomography (CT) and sometimes non-specific radionuclide studies to assess the activity of the disease. Treatment decisions are based on early assessment of the response to therapy and the residual volume of the disease. Our initial experience is reported using a new noninvasive, inexpensive, and reproducible passive imaging modality, Dynamic Infrared Imaging (DIRI), which may add a new dimension to functional imaging. This system relies on its ability to filter the raw infrared signal using biological oscillatory behavior. It detects and analyzes minute oscillations of temperature and heat distribution in tumors.

Bone lymphoma. Comparison of Tl-201 and Ga-67 citrate scintigraphy in assessment of treatment response.

Assessment of response to therapy in patients with lymphoma involving bone can be difficult. Of the scintigraphic techniques available, Tl-201 may be the most ideal radiopharmaceutical because it reflects tumor burden more accurately than either Tc-99m MDP or Ga-67 citrate. We compared serial Tl-201 and Ga-67 citrate scintigraphs (24 studies, 12 pairs) in assessing the response to therapy in three patients with non-Hodgkin's lymphoma involving bone. In two patients who demonstrated a complete remission, uptake of Tl-201 diminished more rapidly and returned to normal earlier than did Ga-67 citrate. Tl-201 did not show tumor recurrence in the one patient with lesions shown to be Tl-201 negative at baseline. Serial studies using Tl-201 may be superior to Ga-67 citrate in the evaluation of lymphoma involving bone provided that Tl-201 avidity is demonstrated on baseline studies.

Scintigraphic and radiographic patterns of skeletal metastases in breast cancer: value of sequential imaging in predicting outcome.

OBJECTIVE: To determine whether temporal changes in scintigraphic and bone radiographic findings have prognostic significance in patients with skeletal metastases from breast cancer. DESIGN: Clinical information and films were retrospectively reviewed in 101 randomly selected patients with skeletal metastases. Images from sequential bond scans and bone radiographs were correlated with survival after detection of the metastases. RESULTS: Time to detection of skeletal metastases and the length of time for which patients were classified as radiologically stable after development of skeletal metastases correlated with survival (r = 0.843; r = 0.821, respectively). Failure to develop a radiographically and scintigraphically stable pattern after treatment was associated with significantly decreased survival compared with the rest of the patients (mean survival 2.1 +/- 1.3 years vs 4.3 +/- 2.3 years; p < 0.001). Scintigraphic regression of metastases was associated with significant survival benefit and longer stabilization of disease compared to all other patterns (mean survival 5.0 +/- 2.7 years of regressive disease vs 3.7 +/- 1.9 years for stable disease and 2.2 +/- 1.3 years for progressive disease; p < 0.001). CONCLUSIONS: Sequential scintigraphic and radiographic imaging is useful in breast cancer patients not only for detection of metastases and monitoring of treatment effect, but also because these studies provide valuable prognostic information.

Healing flare in skeletal metastases from breast cancer.

PURPOSE: To identify the frequency, characteristics, and prognostic significance of scintigraphically detected healing flare in patients with breast cancer metastatic to bone. MATERIALS AND METHODS: Findings on bone scans and concomitant radiographs of 1,188 patients were reviewed. Bone metastases occurred in 426 patients. Outcomes of 101 patients (aged 21-71 years) with skeletal metastases were correlated with typical scintigraphic and radiographic features. RESULTS: Healing flare with increased radiotracer uptake and radiographically demonstrated sclerotic changes in osteolytic or mixed skeletal metastases were prospectively identified in 12% of patients with skeletal metastases. Healing flare was detected 3.2 months +/- 1.4 after initiation of hormonal treatment or chemotherapy. Skeletal metastatic activity stabilized on bone scans within 6.2 months +/- 3.0. Patients with healing flare did not survive longer than patients without healing flare but with stable metastases after treatment (3.3 years +/- 2.0 vs 3.9 years +/- 1.6). CONCLUSION: Scintigraphically detected healing flare represents a favorable response to therapy not associated with increased survival.

Tc-99m HMPAO brain perfusion SPECT in acute aphasia. Correlation with clinical and structural findings.

Tc-99m hexamethylpropylene amineoxime (HMPAO) brain perfusion SPECT was correlated with CT, MRI, and clinical findings in 17 patients with acute and subacute aphasia to determine its diagnostic potential in the early phases of stroke-associated language dysfunction. SPECT was performed using a dedicated brain imaging system after intravenous injection of 20 mCi (740 MBq) of Tc-99m HMPAO. Transaxial and three-dimensional surface rendered images were evaluated visually, and perfusion defects were correlated with CT, MRI, and a standard battery of clinical tests for aphasia. Clinical examination was insufficient for anatomic localization of aphasia in more than 40% of patients. CT exams were normal in 5 patients, although SPECT demonstrated perfusion defects in all 17. Nonfluent aphasia was present in only 6 of 10 patients with perfusion defects in Broca's area and fluent aphasia was present in only 5 of 10 patients with lesions in Wernicke's area. Auditory comprehension defect was associated with perfusion defects in the inferior parietal region in 9 of 12 patients (P = 0.05); reading and writing abnormalities were associated with perfusion defects in the posterior frontal, superior and inferior parietal cortex, and superior temporal gyri, and repetition deficit was associated with defects involving the inferior parietal cortex, the supramarginal and angular gyri, and the ipsilateral thalamus in 8 of 11 patients (P < 0.05). Brain perfusion SPECT should be included in the initial evaluation of aphasic patients, because clinical tests of aphasia and morphological imaging have limited value for accurately determining the extent and location of functional deficits.

Ga-67 scintigraphy after bone marrow harvest. Significance of "sacroiliac" asymmetry in the lymphoma patient.

The importance of recognizing asymmetric Ga-67 citrate uptake in the sacroiliac region after bone marrow harvest and transplant is discussed in a case of non-Hodgkin's lymphoma. The patient underwent chemotherapy, irradiation, and autologous bone marrow transplant for stage IV disease. Ga-67 scintigraphy revealed sacroiliac asymmetry suggesting medial iliac reparative changes after bone marrow harvest. Iliac bone marrow biopsy showed no evidence of infection or of recurrent tumor. Subsequent follow-up imaging and open biopsy demonstrated lymphomatous invasion of adjacent soft tissue where initial findings were thought to represent benign, postharvest changes.

Quantitative evaluation of 99mTc-hexamethylpropylenamineoxime brain SPECT in childhood-onset epilepsy.

In 10 patients with childhood-onset epilepsy, quantitative evaluation (QE) of interictal regional cerebral blood flow (rCBF) using technetium-99m-hexamethylpropylenamine oxime (99mTc HMPAO) single-photon emission computed tomography (SPECT) was correlated with seizure foci localized by electroencephalography (EEG). Eighty regions of interest (5 x 5 pixels) were placed at five different neocortical areas in both cerebral hemispheres, in coronal and transaxial planes. Mean counts/pixel were calculated for each region and multiple right-left comparisons were done. Quantitative evaluation of 99mTc-HMPAO increased detection of rCBF abnormalities by 26%. Abnormal EEG patterns correlated with abnormal rCBF in 75% of cases (Phi = 0.788, p < 0.001), and with visually detected abnormalities in 50% (Phi = 0.493, p < 0.001). Discordance between EEG and SPECT was most frequent in patients with non-localizing EEG (n = 3). In childhood-onset epilepsy, quantitative evaluation of brain perfusion scans provides: (a) objective estimates of interictal rCBF; (b) more precise detection of epileptogenic foci, when used to complement EEG.

Regional cerebral perfusion in Landau-Kleffner syndrome and related childhood aphasias.

Assessment of cerebral perfusion may elucidate pathogenesis of Landau-Kleffner syndrome (LKS). We obtained 99mTc-HMPAO SPECT studies in five children with LKS and in three children with syndromes of verbal-auditory agnosia. In LKS, perfusion showed temporoparietal asymmetry (9.56% +/- 3.44%) (n = 4) or bilateral parietal abnormality (n = 1). SPECT in non-LKS patients was normal (n = 1), showed (n = 1) totihemispheral hypoperfusion accompanying structural abnormality or (n = 1) a pattern resembling but distinct from LKS. Seizures in LKS patients had never occurred (n = 1), were controlled satisfactorily (n = 2), or poorly (n = 2). Maximum EEG abnormality was left centrotemoral-occipital (n = 1), left frontocentral (n = 1), bitemporal/left central (n = 1), and left central/parasagittal (n = 1). Asymmetric temporoparietal perfusion appears characteristic of LKS, differing from findings in other childhood linguistic disturbances. This abnormality occurs across a spectrum of seizure expression, diverging from the distribution of EEG abnormalities. The SPECT abnormalities parallel PET-defined LKS metabolic abnormalities, and may indicate central pathogenetic features of the disorder.

Arterial response to ketanserin and aspirin in patients with advanced peripheral atherosclerosis.

BACKGROUND: In advanced atherosclerosis, endothelial lesions and turbulent flow in stenotic vessels result in platelet aggregation with the liberation of vasoactive factors, including thromboxane A2 and serotonin. This study was designed to assess the combined effect of these factors on arterial dimensions at the time of limb angiography in patients with advanced peripheral vascular disease. METHODS: Diameter changes of 53 segmental stenosis of large arteries were measured in digitized angiograms by a computerized objective method in response to either placebo (13 segments in 7 patients), ketanserin (23 segments in 23 patients), or ketanserin superimposed on aspirin (17 segments in 7 patients). Responses of arterial collaterals were evaluated by a coded assessment. Statistically significant vasodilatation was observed in both the stenotic and post-stenotic segments of the large arteries only when serotonin-2 receptor blockade with ketanserin and cyclo-oxygenase inhibition with aspirin were combined. RESULTS: In the area of the stenosis and in the post-stenotic segment diameter increased 8.2% +/- 2.3% (P = .032) and 7.3% +/- 1.3% (P less than .001), respectively, when aspirin was combined with ketanserin. Significant changes did not occur in either the placebo group or in the group receiving only ketanserin. In the area of stenosis, there was a good correlation between the relative baseline narrowing of the vessel and its vasodilatation after combined ketanserin and aspirin (r = .689; P = .002). Vasodilatation at the level of arterial collaterals also was significantly more pronounced when the combination was used (P less than .001). CONCLUSIONS: These findings suggest a component of vasoconstriction related to the deposition of activated platelets in stenotic segments of the large arteries in atherosclerosis.

Embolization of platelets after endothelial injury to the aorta in rabbits. Assessment with 111indium-labeled platelets and angiography.

This study exploits the ability of a collateral arterial network to trap platelet aggregates in order to document the frequency of macroembolization in rabbits after endothelial damage. Two weeks after ligation of the right superficial femoral artery, endothelial injury was induced in the distal aorta; within 3 hours the rabbits were studied using either angiography or 111indium-labeled (111In) platelet scintigraphy. Angiography indicated visible aggregates in the thigh region in eight of 19 and arterial occlusion in three of 19 rabbits. The collateral-dependent thigh also showed more 111In-labeled platelet activity than the contralateral side (P less than .001), whether platelets were injected before or 2 hours after injury. Radioactivity in the limbs of rabbits with no injury was distributed symmetrically. Blood pool volume, assessed with technetium-99m-labeled red blood cells, was the same in both thighs, and could not account for these observations. The findings indicate that platelet activation and aggregation after endothelial injury lead to microembolization much more frequently than it leads to macroaggregate formation and visible artery occlusion.

201Tl/99mTc-HMPAO SPECT imaging of treated childhood brain tumors.

To assess whether thallium-201 thallous chloride (Tl) can detect childhood tumors and whether diagnostic effectiveness improves with combined blood flow imaging, 28 children (1.0-18.6 years) were studied using single photon emission computed tomography (SPECT): Tl (1.3-1.8 mCi intravenously), followed in 13 of the patients by technetium-99m-hexamethylpropyleneamine oxime (99mTc-HMPAO; 8-18 mCi intravenously). Tl-uptake was markedly increased with histologically confirmed recurrent brain tumors (N = 12). Tl-avid tumors comprised several histologic types, including 6 astrocytomas/gliomas as well as nonastrocytic neoplasms, such as medulloblastoma and ependymoma. A questionable false-positive study was observed with a treated medulloblastoma. Tl failed to detect 5 tumors (i.e., 2 medulloblastomas, 1 ependymoma, 1 malignant schwannoma, and initially 1 low-grade astrocytoma). The sensitivity and specificity of 201Tl-SPECT for detection of childhood brain tumors was 76.9% and 93.3%, respectively. The mean tumor-to-normal brain ratio for Tl was 2.5 +/- 0.5 (N = 7). In some of the patients, 201Tl-SPECT allowed a more precise assessment of the functional state of the tumor than was possible with computed tomography and magnetic resonance imaging. HMPAO distribution was variously normal, increased or decreased at the site of tissue abnormality, and abnormal blood flow was demonstrated in the remaining neuraxis, in 3 of the 7 patients. Changes in tissue perfusion did not correlate with Tl findings, but were evaluated in only one false-negative study.

Platelet activation and aggregation after endothelial injury. Assessment with indium-111-labeled platelets and angiography.

Although platelet activation and aggregation after endothelial injury are well documented, the time course of platelet deposition and the relationship between platelet aggregation and the release of vasoactive products have not been fully clarified in vivo. To study the effect of platelet vasoactive products, a collateral blood supply was induced by ligating the superficial femoral artery in male New Zealand white rabbits. Two weeks later, endothelial injury to the distal abdominal aorta was produced by cytologic brush or mimicked with a metal coil embolus. Platelet aggregation was assessed with indium-111 (111In)-labeled platelets, and scintigraphy demonstrated significant, progressive platelet deposition up to 3 hours after injury and evidence of residual activity 24 hours later. Angiography showed that the time course of peripheral vasoconstriction matched closely that of platelet deposition, indicating release of vasoactive substances from the aggregating platelets. These pathophysiologic changes secondary to endothelial injury may have significant implications for intravascular interventional procedures.