Developing an effective program to complete ictal SPECT in the epilepsy monitoring unit.

With the availability of more stable radiopharmaceuticals, the ictal single photon emission computed tomography (SPECT) perfusion study has emerged as a useful noninvasive functional neuroimaging tool in the presurgical evaluation of patients with medically intractable partial epilepsy. The purpose of this study was to determine whether the development of a program using trained electroencephalography (EEG) technologists to perform ictal injections in the epilepsy monitoring unit enabled a more efficient delivery of radiopharmaceuticals and therefore a higher specificity and sensitivity of outcome. All patients admitted to the epilepsy monitoring unit for prolonged video/EEG monitoring as part of the presurgical evaluation were eligible for completion of an ictal SPECT study using a three-way needle-free apparatus. Over a 19-month period, 85 (77%)) of 110 eligible patients were successfully injected during typical partial seizures. Various factors were analyzed including latency of ictal injection (27.3+/-20.8 [S.D.] s), radiopharmaceutical wastage (40% dose utilization), radiation safety parameters (1.6% contamination rate), and preliminary data of localizing value. Our results show that ictal SPECT can be a safe, noninvasive procedure completed on a routine basis in the epilepsy monitoring unit when appropriately trained support staff are utilized as part of a structured multidisciplinary program.

Sentinel lymph node uptake of two different technetium-labeled radiocolloids,.

BACKGROUND: The study was designed to compare the uptake of technetium-99m-labeled human serum albumin ([99mTc]HSA) and 99mtechnetium-labeled sulfur colloid ([99mTc]SC) in the sentinel lymph nodes (SLNs). METHODS: Radiocolloid levels in the SLN, femoral lymph node (FLN), ischial lymph node (ILN), spleen (SP), and right rear footpad (RRF) were quantitated over a period of 240 min after injection of [99mTc]SC or [99mTc]HSA into the rear footpad of C57 BL/6 mice. RESULTS: There was a significantly greater (p < 0.001) radioactive count in SLNs after [99mTc]SC (mean cpm 211,084.8) compared to [99mTc]HSA (mean cpm 115,640.8). In contrast, the counts in the FLNs were higher after [99mTc]HSA (mean cpm 11,333.4) than after [99mTc]SC injection (mean cpm 5,065.5). The percent uptake in the SP was higher after [99mTc]HSA than after [99mTc]SC injection. CONCLUSIONS: [99mTc]SC is rapidly and efficiently taken up by lymphatics at the primary injection site, is significantly retained in the SLN, and flows slowly to the next echelon node (FLN or ILN) and to the systemic circulation (SP). [99mTc]HSA tends to accumulate less efficiently in the SLN and to disperse more rapidly to the next echelon nodes and to the systemic circulation. By extrapolation, [99mTc]SC is likely to be a better radiocolloid for the intraoperative detection of SLNs.

Rates of flow of technetium 99m--labeled human serum albumin from peripheral injection sites to sentinel lymph nodes.

BACKGROUND: The new technique of sentinel lymphadenectomy for cutaneous melanoma provided us with a unique opportunity to quantitate the rates of lymphatic flow in afferent lymphatics. METHODS: Seventeen melanoma patients underwent preoperative lymphoscintigraphy with technetium 99m-human serum albumin (HSA). The time and distance between the injection site and the sentinel lymph node (LN) were recorded. By comparison, lymphatic flow rates between footpad, popliteal LN, femoral LN, and systemic blood were measured in 60 female mice (C57BL/6) after footpad injection of 99mTc-HSA. RESULTS: The rate of lymphatic flow to 14 axillary, four inguinal, one popliteal, and one parotid sentinel LNs averaged 10.4 +/- 7.3 cm/min. In contrast, the lymphatic flow rate between the footpad and the popliteal LN in mice (analogous to the sentinel LN in human beings) averaged 1.33 +/- 0.52 cm/min. There was a marked delay in the passage of radionuclide through the popliteal LN with consequent slowing of the rate of flow between the popliteal and femoral LNs to 0.22 cm/min. CONCLUSION: Lymphatic flow to the sentinel LN occurs rapidly from both human skin and murine footpads. This information might be helpful in planning the timing of the incision after vital blue dye injection for identifying the sentinel LN.

Scintigraphic demonstration of a right-to-left intracardiac shunt in a patient with massive pulmonary emboli.

A case of massive pulmonary embolism resulting in marked pulmonary to systemic shunting in a patient with a previously clinically inapparent ventricular or atrial septal defect is presented. The various types of unrecognized intracardiac shunts and their prevalence in the adult population are discussed.

Barrett esophagus: decreased esophageal clearance shown by radionuclide esophageal scintigraphy.

Radionuclide esophageal scintigraphy is a sensitive test of esophageal function, but its usefulness is not well documented in Barrett esophagus. This technique was prospectively studied in 27 patients with histologically proved Barrett esophagus and 17 patients with biopsy-confirmed reflux esophagitis. The esophageal transit time and percentage of emptying were calculated. The only quantitative parameter of radionuclide esophageal scintigraphy to show a significant difference between the two conditions was the percentage of emptying, which was abnormal in 48% of patients with Barrett esophagus versus 31% of patients with reflux esophagitis. In the latter group, the mean percentage of emptying approached normal (89.5%), while in the former group it was decreased to 82.1% (P less than .05). Neither emptying parameter correlated with length of Barrett esophagus. These data support the hypothesis of inherent esophageal dysmotility in Barrett esophagus. Half of the patients with this condition have impaired esophageal clearance and may benefit from drug therapy.

Solid-phase gastric emptying in patients with Barrett's esophagus.

Delayed gastric emptying as a pathophysiologic factor in patients with gastroesophageal reflux (GER) is controversial. In order to further evaluate this question, we studied a population with severe reflux, specifically, patients with Barrett's esophagus. Solid-phase gastric emptying was measured in 17 patients and in 17 healthy volunteers using radionuclide imaging. Gastric emptying was variable among these patients with 70% normal, 18% rapid, and only 12% slow studies. From these observations, we conclude that delayed gastric emptying is unlikely to be a major factor in the pathogenesis of Barrett's esophagus.