Brain SPECT evaluation of patients with pure photosensitive epilepsy.

UNLABELLED: This study was performed to determine the utility of 99mTc-HMPAO brain SPECT in evaluating patients with pure photosensitive epilepsy. METHODS: Seven patients (2 boys, 5 girls), aged 8 to 15 yr (mean 11.1 +/- 2.5 yr), were studied. All patients underwent a detailed neurologic examination, interictal and ictal EEGs, CT and/or MRI and SPECT imaging. The baseline SPECT study was performed during the interictal period and the activation study was performed while the patients were having seizures provoked by watching television. RESULTS: The baseline SPECT study showed that six of seven patients had relatively hypoperfused regions in their frontal lobes that could involve the neighboring parietal and temporal regions. The activation study revealed that all seven patients had relative hyperperfusion in these brain regions that were relatively hypoperfused in the baseline study. The side-to-side asymmetry indexes for these visually-interpreted rCBF abnormalities ranged from 3% to 6%. CONCLUSION: The relatively consistent pattern of frontal rCBF alterations suggests that frontal lobe functions were implicated in the evolution of photosensitivity-related seizures in patients with pure photosensitive epilepsy.

Evaluation of therapy response in children with untreated malignant lymphomas using technetium-99m-sestamibi.

UNLABELLED: The aim of this study was to investigate the relationship between 99mTc-sestamibi accumulation in tumors and response to chemotherapy in children with untreated malignant lymphomas. METHODS: Twenty-four children with malignant lymphoma (16 with Hodgkin's disease and 8 with non-Hodgkin's lymphoma) were studied with 201Tl and then with 99mTc-sestamibi scintigraphy before any therapeutic intervention. Visual and quantitative interpretation of 201Tl and 99mTc-sestamibi scans were performed. Visual uptake scores > or = 2+ were considered positive studies for 201Tl and 99mTc-sestamibi scintigraphy. Remission rates were evaluated at the end of induction therapy; patients were then followed clinically for 1-2 yr. RESULTS: All 17 patients who had positive 99mTc-sestamibi scans subsequently had a complete response to chemotherapy; all seven patients who had negative 99mTc-sestamibi scans subsequently had partial or no response to chemotherapy, irrespective of the lymphoma type. The mean tumor-to-background ratios of patients with complete response and with partial or no response were 1.395 +/- 0.2 and 1.031 +/- 0.05 (p = 0.0002), respectively. Thallium-201 scintigraphy results were not related to the response to chemotherapy. CONCLUSION: Technetium-99m-sestamibi scintigraphy can provide information predicting the response to chemotherapy in patients with malignant lymphoma.

D2 receptor imaging with iodine-123-iodobenzamide brain SPECT in infants with hypoxic-ischemic brain injury.

UNLABELLED: The purpose of this study was to evaluate the striatal dopamine D2 receptor density in infants with perinatal hypoxic-ischemic brain injury (HIBI) using 123I-iodobenzamide (IBZM) brain SPECT and to correlate the findings with the severity of HIBI and neurologic outcome. METHODS: Twenty infants who were diagnosed to have perinatal HIBI were included in this study. They were classified as having mild (n = 6), moderate (n = 10) or severe (n = 4) HIBI according to their neurologic findings at birth using the criteria of Sarnat and Sarnat. Neurologic outcome of these infants was determined by serial neurologic examinations and the Denver developmental screening test; 10 infants recovered without any deficit and the remaining 10 were affected to a degree varying from motor impairment to cerebral palsy. All 20 infants were examined using 123I-IBZM brain SPECT at age 7.8 +/- 2.3 mo. Transaxial slices were obtained 2 hr after intravenous injection of 300 micro ci (11.1 MBq) 123I-IBZM and the activity ratios of striatal to occipital cortex (ST/OC) were calculated. RESULTS: The mean ST/OC ratios in patients with mild, moderate and severe HIBI (1.219 +/- 0.078, 1.097 +/- 0.069 and 0.813 +/- 0.140, respectively) were significantly different from each other (p = 0.001). The infants who recovered from HIBI without any neurologic sequelae had higher mean ST/OC ratios than the others (1.184 +/- 0.010 versus 0.969 +/- 0.160, p = 0.002). CONCLUSION: The results of this study show that in infants with HIBI, striatal D2 receptor density decreases as the severity of injury increases. The D2 receptor density is higher in infants who recover without neurologic deficits compared to those who are affected neurologically. Dopamine D2 receptor imaging can be used to assess the severity of HIBI in children.

Fluorine-18-fluorodeoxyglucose uptake in pneumonia.

Whole-body PET imaging with 18F-fluorodeoxyglucose (FDG) has been shown to be effective in distinguishing benign and malignant pulmonary disease. Mild elevations in FDG uptake with standardized uptake values (SUVs) less than 2.5 have been reported in benign lesions, including pneumonia. We report a case of presumed bacterial pneumonia with markedly elevated FDG uptake in a patient with a concomitant squamous cell carcinoma in the contralateral lung. SUV's were similar for both lesions (4.9 and 5.4). This case demonstrates an inflammatory etiology for false-positive FDG PET imaging in the evaluation of focal pulmonary abnormalities.

Evaluation of pentavalent Tc-99m DMSA scintigraphy in small cell and nonsmall cell lung cancers.

AIM: The purpose of this study was to evaluate the clinical usefulness of Tc-99m (V) DMSA in patients suspected of lung cancer and determine whether this agent may have value in differentiation between small cell (SCLC) and non-small cell (NSCLC) lung carcinoma. METHODS: Thirty-six patients with clinical and radiological suspicion of primary lung carcinoma were injected 450-600 MBq of Tc-99m (V) DMSA intravenously. Whole body and planar anterior, posterior thorax images were obtained 4-5 h after injection of the radioactive complex. RESULTS: Histopathological results confirmed 23 NSCLC, 10 SCLC and 1 metastatic lung carcinoma and 2 lung abscess. Nineteen of the 23 (82%) NSCLC and all of the 10 (100%) SCLC cases showed Tc-99m (V) DMSA uptake. Single metastatic lung cancer also accumulated radiotracer. Lung abscess did not show uptake. Lesion/Nonlesion (L/N) ratio of SCLC (1.59 +/- 0.32) and NSCLC (1.43 +/- 0.19) tumour types did not show statistical difference (p > 0.05). Tc-99m (V) DMSA whole body imaging also showed bone metastases. CONCLUSION: Tc-99m (V) DMSA is a noninvasive and cheap imaging method to detect malignant lung cancers and their bone metastases but, differentiation of SCLC and NSCLC is not possible.

Functional assessment of human gastrointestinal tract using 99Tcm-latex particles.

99Tcm-latex particles (LP) is a newly developed radiopharmaceutical for the evaluation of the gastrointestinal (GI) tract. Following oral ingestion, it passes through the entire GI tract undissolved. The purpose of the present investigation was to introduce the clinical application of 99Tcm-LP. A group of 11 healthy volunteers was studied. Following a 12 h fast, the subjects were given 150 ml of water containing 37 MBq of 99Tcm-LP orally. Dynamic images up to 2 h were recorded to document temporal progression of radioactivity. Static images of the abdomen and whole body were taken at intervals. In normal subjects the tracer arrival times at the caecum and sigmoid colon were 3.2 +/- 0.9 and 11.2 +/- 3.2 h, respectively. The average t1/2 value for gastric emptying, 50% colonic filling and small bowel transit time were found to be 21.6 +/- 5.6, 233 +/- 72 and 211 +/- 66.4 min, respectively. In conclusion, 99Tcm-LP has the potential of providing functional information of the GI tract.

Renal infarct: contrast-enhanced power Doppler sonographic findings.

Power Doppler sonography (PDUS) is a promising technique for the diagnosis of renal infarcts. PDUS's efficacy may be enhanced by using sonographic contrast agents. We evaluated 3 cases of renal infarction using PDUS and the sonographic contrast agent Levovist. The findings were compared with those of other imaging modalities, such as scintigraphy, CT, and angiography. In case 1, PDUS showed a patent interlobar artery only in the lower part of the right kidney and no other perfusion of the right renal parenchyma. Contrast-enhanced PDUS showed patchy areas of preserved perfusion in the lower and middle-upper anterior portions of the kidney. In case 2, PDUS showed diffuse and patchy perfusion defects in the anterolateral portion of the right kidney. On contrast-enhanced PDUS, no signal enhancement was seen in these areas, but the perfusion defects were better delineated. In case 3, PDUS showed no perfusion in the upper pole of the kidney; the nonperfused area extended to the posterior upper portion of the kidney but could not be distinguished from normal tissue. After injection of the contrast agent, there was no enhancement of the posterior extension of the upper pole infarct, but Doppler signals from the surrounding normal parenchyma were enhanced, so the area was more clearly demarcated. The administration of the contrast agent facilitated the visualization of the infarcts in all 3 cases.

A rabbit model of human familial, nonsyndromic unicoronal suture synostosis. II. Intracranial contents, intracranial volume, and intracranial pressure.

This two-part study reviews data from a recently developed colony of New Zealand white rabbits with familial, nonsyndromic unilateral coronal suture synostosis, and this second part presents neuropathological findings and age-related changes in intracranial volume (ICV) and intracranial pressure (ICP) in 106 normal rabbits and 56 craniosynostotic rabbits from this colony. Brain morphology and anteroposterior length were described in 44 rabbit fetuses and perinates (27 normal; 17 synostosed). Middle meningeal artery patterns were qualitatively assessed from 2-D PCC MRI VENC scans and endocranial tracings from 15, 126-day-old rabbits (8 normal, 7 rabbits with unicoronal synostosis). Brain metabolism was evaluated by assessing 18F-FDG uptake with high-resolution PET scanning in 7, 25-day-old rabbits (3 normal, 4 with unicoronal or bicoronal synostosis). Intracranial contents and ICV were assessed using 3-D CT scanning of the skulls of 30 rabbits (20 normal,10 with unicoronal synostosis) at 42 and 126 days of age. Serial ICP data were collected from 66 rabbits (49 normal; 17 with unicoronal synostosis) at 25 and 42 days of age. ICP was assessed in the epidural space using a Codman NeuroMonitor microsensor transducer. Results revealed that cerebral cortex morphology was similar between normal and synostosed fetuses around the time of synostosis. Significantly (P<0.05) decreased A-P cerebral hemisphere growth rates and asymmetrical cortical remodeling were noted with increasing age in synostotic rabbits. In addition, rabbits with unicoronal suture synostosis exhibited asymmetrical middle meningeal artery patterns, decreased and asymmetrical brain metabolism, a "beaten-copper" intracranial appearance, significantly (P<0.05) decreased ICV, and significantly (P<0.01) elevated ICP compared with normal control rabbits. The advantages and disadvantages of these rabbits as a model for human familial, nonsyndromic unicoronal suture synostosis are discussed, especially in light of recent clinical neuropathological, ICV, and ICP findings recorded in human craniosynostotic studies.