Intra-operative use of PET probe for localization of FDG avid lesions.

Localizing positron emission tomography (PET)/computed tomography (CT) findings in heavily scarred surgical fields can be challenging. A high energy gamma probe (PET probe) can be used to guide surgery in those difficult areas. We describe our experience localizing and removing fluorodeoxyglucose (FDG) avid lesions in different body areas. Between 2004 and 2007, we used the PET probe to localize and remove 12 lesions from 9 patients. The lesions were removed confirming ex vivo and tumor bed FDG activity. Five patients had lesions in previously operated and sometimes radiated fields. One patient had FDG avid spots in the retroperitoneum. Two lymphoma patients had been previously treated and had new FDG avid spots in a background of scarred nodes. The last patient had a core biopsy suspicious for lymphoma but a repeat CT was non-specific. One patient with gastric cancer patient, two patients with melanoma patients and two patients with breast cancer had 10 metastatic lesions easily identified and removed. After a median follow-up of 14 months all five patients are alive. The two patients with lymphoma had their FDG avid lymph nodes easily identified and biopsied. In one patient with melanoma and one patient with suspected lymphoma, the preoperative scan revealed no FDG avid lesions. The PET probe confirmed this finding in the operating room. Clinical applications of PET probe guided surgery include restaging for previously treated lymphoma patients, localization and resection of metastatic FDG avid nodules especially in previously operated or radiated fields and biopsy of PET findings difficult to localize.

Chorea and contraceptives: case report with pet study and review of the literature.

Chorea is a well-recognized but rare complication of oral contraceptive use. A 27-year-old woman developed right hemichorea while taking an oral contraceptive (OC). No other causes of chorea were found. A positron emission tomography (PET) study with (18)F-fluorodeoxyglucose demonstrated a dense focus of increased glucose metabolism involving the body of the left caudate nucleus. To our knowledge, this is the first report of a PET study in a patient with OC-induced chorea in the absence of systemic lupus erythematosus or antiphospholipid antibodies.

MAG3-F0 scintigraphy in decision making for emergency intervention in renal colic after helical CT positive for a urolith.

UNLABELLED: Patients with renal colic are evaluated with clinical, laboratory, and imaging methods for stratification for emergency decompression, medical treatment, or discharge and follow up. The current standard practice is heavily based on unenhanced helical CT for detecting uroliths. However, the presence of a urolith does not necessarily mean that the kidney is obstructed and requires emergency decompression. In this study, technetium-mercaptoacetyltriglycine (MAG3) diuretic scintirenography was used to detect obstruction in patients with renal colic. The contribution of this test to patient management after positive findings from helical CT was also studied. METHODS: Diagnostic criteria were established on the basis of previous experience with 60 patients who had renal colic and had undergone radiography of the kidneys, ureters, and urinary bladder (KUB) and diuretic Tc-MAG3 scintirenography and were followed up to correlate scintigraphic findings with clinical outcome. Subsequently, 80 patients with renal colic underwent scintigraphy within 12 h of presentation in the emergency room, after abdominal helical CT showed findings positive for calculus and suggestive of obstruction. After therapeutic oral or intravenous hydration and analgesics, diuretic dynamic renal scintigraphy (flow, function, delayed imaging) was performed after intravenous injections of 10 mCi (370 MBq) 99mTc-MAG3 and 40 mg furosemide (at zero time, or F0). Results were available soon after completion of the study and were considered in patient management. Four characteristic patterns of scintirenography, essential in patient stratification and treatment, had been standardized and were used for interpretation of the studies: the unobstructed kidney; the partially obstructed kidney, proximally or distally obstructed, with mild to severe obstruction and impairment of function; the totally obstructed kidney, with arrested renal function; and the unobstructed but dysfunctioning kidney after decompression, or stunned kidney. RESULTS: Among the 80 patients with positive helical CT findings, 56.5% were found to have obstruction by scintigraphy (32.5% partially, 24% completely); the remaining 43.5% did not have obstruction (21% without an indication of recent obstruction and 22.5% with stunned kidneys after spontaneous decompression). Occasionally, findings of preexistent urine extravasation or infection were present. Patients who, by scintigraphy, never had obstruction or had experienced spontaneous decompression did not require admission or emergency intervention; those with complete or severe obstruction required admission and decompression for relief of pain or restoration of function, whereas those with mild obstruction were treated variably with forced fluids, analgesics, or, less frequently, elective surgery. Outcome information from clinical examination, imaging, and interventional findings indicated that this stratification was successful. The test caused no side effects. CONCLUSION: For renal colic, clinical selection, KUB radiography, and even positive helical CT findings were all found to have a low positive predictive value for obstruction (in this study, 35%, 32%, and 56% respectively). Anatomic studies, including helical CT, should be followed by diuretic MAG3-F0 scintirenography to diagnose and quantify or exclude obstruction, detect spontaneous decompression, and appropriately stratify patients for emergency intervention, observation and medical therapy, or further work-up and discharge with referral to the clinic.

Diuretic MAG3 scintirenography in children with HIV nephropathy: diffuse parenchymal dysfunction.

UNLABELLED: HIV nephropathy (HIVN) is prevalent in 15%-56% of HIV-infected children and induces mild to severe progressive nephropathy. METHODS: A total of 33 renal diuretic scintirenographic studies with 99mTc-mercaptoacetyltriglycine (MAG3) were reviewed and analyzed from 23 HIV pediatric patients, 21 of whom had HIVN with varying degrees of renal impairment. Results were compared with 10 studies of control patients of matching ages. Visual interpretation of images and renograms as well as semiquantitative analyses were performed. Variables compared were size of kidneys, time of peak and one-half peak activities, residual (or retained) cortical activity at 20 min, ratio of cortical activity at 2.5-20 min, and ratio of kidney activity to kidney plus background activity at 2 min. The results of MAG3 renal studies were also compared with laboratory data pertaining to creatinine clearance in all patients and with sonography in 17 patients. RESULTS: In most patients with HIVN (18/21), the kidneys were larger than normal, with a diffuse parenchymal dysfunction (decreased uptake, slow processing, and increased retention of activity) and flat renograms, findings similar to those observed in other diffuse parenchymal diseases. In all patients with HIVN, semiquantitative analysis (paired t test) showed statistically significant differences from control patients for all variables. On ANOVA, a statistically significant correlation was found between most scintigraphic parameters and the severity of renal impairment. Of the 17 concurrent sonographic studies in HIVN patients, 7 showed no abnormalities, whereas the results of scintigraphy were abnormal. CONCLUSION: Diuretic MAG3 scintirenography shows nonspecific diffuse parenchymal dysfunction in pediatric patients with HIVN. Such dysfunction may provide corroborative evidence of HIVN and should be recognized when the test is performed for standard indications. Further work is necessary to prove that the test has indeed the high sensitivity and good correlation with the seventy of HIVN suggested in this population; the test may be useful to follow up the progression of disease and the effect of treatment.

Diuretic MAG3 scintigraphy (F0) in acute pyelonephritis: regional parenchymal dysfunction and comparison with DMSA.

UNLABELLED: 99mTc-DMSA late static planar imaging or SPECT is being used for the investigation of focal acute pyelonephritis (APN), especially in children with urinary tract infection (UTI). Diuretic 99mTc-mercaptoacetyltriglycine (MAG3) dynamic scintirenography has been applied in the evaluation of kidney function and structure, frequently to exclude obstruction. However, in children and adults with a clinical picture of APN, diuretic MAG3 scintigraphy with zero time injection of furosemide (MAG3-F0) was observed to display focal parenchymal abnormalities; regional dysfunction (focal parenchymal decrease in early uptake; slow filling in and prolonged late retention of activity); or, less frequently, fixed defects. This observation was further studied both retrospectively and prospectively, and its sensitivity and specificity for APN were compared with those of dimercaptosuccinic acid (DMSA). METHODS: In the retrospective study, for 36 children with UTI and regional parenchymal findings on MAG3-F(0), data were reviewed, analyzed, and compared with the results of concurrent DMSA studies. In the prospective study, for 57 children with clinical and laboratory findings suggestive of APN, the 2 radiopharmaceuticals were used for imaging sequentially and the results of the 2 studies were compared. The criteria for abnormal findings compatible with the diagnosis of APN were, for MAG3-F(0), regional parenchymal dysfunction and fixed focal defects and, for DMSA, focal defects without parenchymal loss. RESULTS: In all groups of patients, most abnormal MAG3-F(0) studies (80%) showed regional parenchymal dysfunction, but in some (20%) a fixed defect was found. Compared with DMSA and when both regional dysfunction and focal defects were considered, MAG3-F(0) was as sensitive as DMSA. Some patients had only MAG3-F(0) abnormalities, suggesting a slightly lower specificity for MAG3-F(0) compared with DMSA (86%); this finding needs further study, because it also raises questions about the sensitivity of DMSA, considering that only a small percentage of patients with clinically suggestive findings had abnormal study findings. In most patients with fixed defects on both DMSA and MAG3-F(0), follow-up studies showed no resolution, suggesting that a fixed defect on MAG3-F(0) may indicate either more severe APN or preexistent scars and that regional dysfunction may be a sign more specific for APN and prognostic of potential recovery. In addition, a pattern more specific for a scar--a fixed defect with a dilated regional calyx--was seen on follow-up MAG3-F(0). CONCLUSION: A fast (25-min) planar dynamic MAG3-F(0) study was found to be as sensitive at depicting focal parenchymal abnormalities in APN as was the 3- to 4-h DMSA routine procedure. The sensitivity and specificity of both studies need further evaluation.

ACE inhibition scintigraphy in the management of hypertension in children.

Angiotensin converting enzyme (ACE) inhibition scintirenography was performed to help establish the diagnosis and plan treatment of renovascular hypertension (RVH) in 57 hypertensive pediatric patients, 33 infants and 24 children older than 1 year. In 16 of 33 hypertensive infants, ACE inhibition scintirenography established the diagnosis of RVH from renal ischemia (due to aortic or renal arterial thrombi). Two scintigraphic criteria were used for the diagnosis of RVH: criterion I, ischemic and damaged kidney (a non-functioning kidney on or off ACE inhibition) and criterion II, ischemic but not damaged kidney (ACE inhibition induced deterioration of function of the kidney). When criterion I was present and the contralateral kidney was normal, ACE inhibitors could be used for treatment of hypertension without deterioration of renal function; kidneys satisfying criterion I eventually involuted or manifested growth arrest and frequently caused persistent RVH, even after resolution of the thrombus, requiring nephrectomy. When criterion II was present bilaterally, or it was associated with criterion I contralaterally, the use of antihypertensive drugs other than ACE inhibitors was necessary in order to prevent renal insufficiency or failure from ACE inhibitors. However, kidneys with criterion II showed normal growth and, following retraction or dissolution of the aortic thrombus, hypertension resolved. In 2 of 24 hypertensive children older than 1 year, the test was diagnostic of branch renal artery stenosis; RVH was cured by selective angioplasty. ACE inhibition scintirenography is useful in the evaluation and planning of treatment in children with hypertension and may predict the outcome of therapy and ultimate renal function.

A thousand points of light or just dim bulbs? Radiolabeled antibodies and colorectal cancer imaging.

Radioimmunoscintigraphy (RIS) is coming into its own as an imaging modality in clinical oncology. Early experience with indium-111-labeled intact murine monoclonal antibodies (MoAbs) in colorectal cancer suggested that RIS images hepatic metastases poorly. Moreover, an antimurine immune response was frequently provoked, precluding multiple follow-up RIS studies in individual patients due to reticuloendothelial sequestration of the radioimmunoconjugate before tumor targeting could occur. Recent trials of technetium-99m-labeled antibody fragments and human MoAbs have demonstrated significant improvement in imaging efficacy, and repeated or serial imaging is possible because of the absence of associated immunogenicity. RIS is demonstrably more sensitive than conventional diagnostic modalities (CDM) such as computed tomography (CT) for detection of extrahepatic abdominal and pelvic colorectal carcinoma and is complementary to CDM in imaging liver metastases. In a surgical decision-making analysis comparing CT, RIS (IMMU-4 99mTc-Fab'; CEA-Scan), and CT plus RIS in patients with recurrent or metastatic colorectal cancer, CT plus RIS improved correct prediction of resectability by 40% and correct prediction of unresectability by 100% compared with CT alone. At the present time, RIS used in combination with CDM contributes an incremental improvement in diagnostic accuracy in colorectal cancer patients with known or suspected recurrent disease. Basic and clinical research currently in progress promises to yield agents and methods that provide rapid high-resolution imaging, high tumor-to-background ratios in all organs at risk for tumor recurrence or metastasis, negligible immunogenicity and toxicity, and a significant further improvement in the accuracy of clinical decision making in oncology patients.

Pseudoaneurysm of the superior mesenteric artery with an arteriovenous fistula after simultaneous kidney-pancreas transplantation.

Vascular complications remain a significant source of morbidity after pancreatic transplantation. We describe a pseudoaneurysm of the superior mesenteric artery (SMA) with an arteriovenous fistula (AVF) involving the SMA and the superior mesenteric vein (SMV) discovered and treated surgically in the second week after kidney pancreas transplantation. The patient experienced pain over the graft, and subsequent radionuclide and Doppler ultrasound scan were suggestive of a pseudoaneurysm in the head of the pancreas. Awaiting confirmatory angiography, the patient became hypotensive and after resuscitation, underwent emergency surgery when a pseudoaneurysm was found in the head of the pancreas. After looping the proximal and distal recipient iliac artery and base of the donor Y vascular graft, the AVF was separated and ligated. The SMV was dissected off the pancreatic head and repaired over a tamponading intraluminal Foley catheter. Graft function was preserved. Based on this experience, an AVF with or without a pseudoaneurysm in the pancreas allograft should be corrected as soon it is suspected.

Pertechnetate scintigraphy in primary congenital hypothyroidism.

UNLABELLED: Primary congenital hypothyroidism (PCH) is currently detected effectively by heel-stick screening. When elevated thyrotropin (TSH) and/or decreased T4 are found in the blood of neonates, they are recalled, values are confirmed in venous blood and thyroxine replacement therapy (TRT) is immediately instituted, thus cretinism or severe retardation is prevented. However, in a significant percentage of neonates with abnormal blood levels of T4 or TSH, the disorder is transient. To help determine the exact cause of PCH and the possibility of transient PCH, pinhole thyroid imaging is performed 30 min after an intravenous injection of 18.5 MBq (500 microCi) 99mTc-pertechnetate (TcPT). Patients with a nonvisualized gland or patients with images suggesting dyshormonogenesis are reevaluated at age 3-4 y to exclude transient PCH. METHODS: To define the role of TcPT imaging in determining the exact etiology of PCH and the possibility of its being transient, we reviewed data from 103 neonates with PCH who had scintigraphy in our laboratory between 1970 and 1996 and we correlated the results with clinical outcome. RESULTS: Four patterns of thyroid scintigrams were recognized and these determined patient classification: (a) normal in 7 patients with false-positive heel-stick screening but normal venous blood hormone levels; (b) hypoplasia-ectopia in 32 patients requiring lifelong TRT; (c) nonvisualization in 35 patients-32 with agenesis requiring lifelong TRT and 3 with fetal thyroid suppression by maternal antibodies whose TRT was discontinued at a later age; and (d) dyshormonogenesis (markedly increased TcPT concentration) in 29 patients-25 with permanent PCH requiring lifelong TRT and 4 with transient PCH in whom TRT was discontinued. Of the 25 patients with dyshormonogenesis, 12 belonged to five families with two or three siblings having the same disorder. CONCLUSION: TcPT thyroid scintigraphy in the neonate with PCH provides a more specific diagnosis, is useful for selecting patients for re-evaluation to uncover transient PCH and discontinue TRT and defines dyshormonogenesis, which is familial and requires genetic counseling. It is also cost-effective.

Report of the Radionuclides in Nephrourology Committee for evaluation of transplanted kidney (review of techniques).

Comprehensive evaluation of renal transplants has been important in differential diagnosis of medical and surgical complications in the early post-transplantation period and in the long-term follow-up. If performed well, it yields excellent functional and good anatomic information about the graft that can be effectively used in the patient. That includes selection of patients for biopsy and for various drug regimens. This is true especially in patients with anuric acute tubular necrosis (ATN) and in patients with developing chronic rejection. Improving indices of renal function (effective renal plasma flow, uptake of tubular tracers) can indicate resolution of tubular injury (ATN) while there is still no improvement in plasma creatinine. In patients with chronic rejection, plasma creatinine increases only after approximately 30% of renal function is lost due to graft fibrosis. Early recognition of this condition could permit treatment and delay of retransplantation. The protocol recommended at the Copenhagen meeting includes a flow study, scintigram of the kidneys, prevoid and postvoid bladder image, injection site image (quality control), time/activity curves of the graft and bladder, and quantitative data of perfusion, function, and tracer transit. The flow study obtained during the initial transit of the bolus through the graft could be performed either with 99mTc mercaptoacetyltriglycine, or 99mTc diethylenetriaminepentaacetate (DTPA). Quantitative analysis of perfusion facilitates interpretation of the study during the early post-transplantation period. ATN, common in cadaver transplants, typically shows adequate perfusion. The function phase should include images and time/activity curves. Images alone are insufficient. Quantitative data such as clearance or other indices of function and indices of tracer transit are essential for correct interpretation of the results. Normal images and normal graft function reliably exclude clinically important complications. A single scintigram demonstrating prolonged tracer transit with decreased function cannot separate acute rejection and ATN. On serial studies, decline in function and poor perfusion are indicative of acute rejection. A normally appearing scintigram without cortical retention, but with low function, is consistent with chronic rejection. Pharmacological intervention to exclude obstruction (diuretic renogram) or hemodynamically significant renal artery stenosis (angiotensin converting enzyme challenge) should be used whenever indicated.

Unfiltered sulfur colloid and sentinel node biopsy for breast cancer: technical and kinetic considerations.

BACKGROUND: There are few clinical data on technical limitations and radiocolloid kinetics related to sentinel lymph node (SLN) biopsy for breast cancer. METHODS: In 70 clinical node-negative patients, unfiltered 99mTc sulfur-colloid was injected peritumorally and cutaneous hot spots were mapped with a gamma probe. SLN biopsy was performed followed by axillary lymph node dissection. Missed radioactive nodes (nodes not under hot spots) were removed from axillary lymph node dissection specimens and submitted separately. RESULTS: At least one hot spot was mapped in 69 patients (98%) and SLNs were retrieved in 62 (89%). No radiolabeled nodes were found in five (7%) and only nodes not under hot spots were retrieved in three patients (4%). Residual nodes not under hot spots were retrieved in 17 patients (24%) in whom at least one SLN specimen had been found. Diffuse radioactivity around the radiocolloid injection site impeded identification of all radiolabeled nodes during SLN biopsy, and was responsible for one of two false negatives (20 node-positive patients; false-negative rate 10%). Hot spot radioactivity, number of radiolabeled nodes, and nodal radioactivity did not change with time interval from radiocolloid injection to surgery (0.75-6.25 hours). CONCLUSIONS: Although SLN localization rate is high, intraparenchymal injection may predispose to failure of radiocolloid migration, failure to identify SLNs because of high radiation background, and false-negative outcomes. Alternative routes of radiocolloid administration should be explored.

Sentinel lymph node localization in early breast cancer.

METHODS: Thirty-two patients with clinical node-negative breast cancer underwent sentinel node localization study as part of a National Cancer Institute-sponsored multicenter trial. Anatomical and histopathologic characteristics of sentinel lymph node (SLN) and a kinetic analysis of nodal uptake were studied. Patients were injected with 1 mCi/4 ml unfiltered 99mTc-sulfur colloid in four divided doses around the palpable lesion or immediately adjacent to the excision cavity if prior biopsy was performed. SLN biopsy was performed 1.5-6 hr (mean = 3 hr) postinjection. Intraoperative localization was performed using a gamma probe. All patients underwent complete axillary dissection. RESULTS: SLN was identified in 30 of 32 (94%) patients. There were no false-negative SLN biopsies. CONCLUSION: This study supports the clinical validity of SLN biopsy in breast cancer and confirms that, unlike the blue dye technique, the learning curve with unfiltered 99mTc-sulfur colloid and the gamma detection probe is short, and SLN localization is achievable in over 90% of cases by surgeons with modest experience. The use of unfiltered 99mTc-sulfur colloid (larger particle size) with larger injected volume permits effective localization of SLNs.

Somatostatin receptor expression in Hürthle cell cancer of the thyroid.

Somatostatin receptor expression, which was not a previously described marker for Hürthle cell cancer of the thyroid, was demonstrated by in vivo imaging with (111)In-pentetreotide in three patients. This phenomenon not only adds another imaging technique to the nuclear medicine armamentarium for detecting recurrent and metastatic cancer in patients with Hürthle cell cancer but also opens up an alternative therapeutic avenue with somatostatin analogs or their radiolabeled compounds.

MAG3 SPECT: a rapid procedure to evaluate the renal parenchyma.

UNLABELLED: Renal parenchymal (cortical) scintigraphy (planar or SPECT) is indicated for the diagnosis and follow-up of focal functional disorders, such as acute pyelonephritis, and for accurate quantitation of split renal function, especially in cases of atypical location of the kidney(s). This static imaging procedure is currently performed 3-5 hr after the injection of a cortical fixation agent, 99mTc-DMSA or 99mTc-GH, and requires effective immobilization of the patient for 30 min. METHODS: In five healthy adult volunteers and five children with various clinical indications, SPECT renal parenchymal scintigraphy was performed with a three-detector camera in 1-min per revolution sequential intervals for a total acquisition time of 4 min, beginning immediately after an intravenous injection of a graduated dose of 20 mCi (minimum 2 mCi) of the dynamic renal agent 99mTc-MAG3. RESULTS: Tomograms of the renal parenchyma reconstructed in three projections and volume-rendered reprojection of the SPECT-volume data indicated normal or abnormal renal parenchyma. Comparisons were made with planar MAG3 and SPECT-GH and favored MAG3-SPECT. However, comparisons with DMSA indicated certain disadvantages of MAG3 SPECT. For most organs, the radiation dose estimates from 20 mCi MAG3 were lower than those from DMSA (6 mCi) or GH (20 mCi). Simultaneous injection of MAG3 and a diuretic (2-40 mg furosemide) resulted in lower than usually reported radiation dose estimates for the urinary bladder (target organ) and the gonads, and allowed subsequent evaluation of the drainage system. CONCLUSION: MAG3 SPECT is feasible, clinically useful and may be offered as a rapid (4 min) renal parenchymal imaging procedure, or it may precede planar dynamic (dluretic) MAG3 scintigraphy.

Emboli from an extraluminal blood flow hollow fiber oxygenator with and without an arterial filter during cardiopulmonary bypass in a pig model.

The effect of an arterial filter on visceral emboli was quantified with autologous indium-111 labeled platelets (INPLT) during cardiopulmonary bypass (CPB) in Yorkshire pigs. Biodistribution of INPLT was determined in 12 control pigs (30-35 kg, unoperated control [n = 6] and sham operated control [n = 6]). CPB was carried out with (n = 6) and without (n = 6) an arterial filter in 12 pigs at a flow rate of 2.5-3.5 L/min. Platelets labeled with In-111 tropolone (650-780 microCi) were injected intravenously 24 hr before CPB. All pigs were systemically heparinized (activated coagulation time > 400 sec); CPB was instituted with a roller pump, an extraluminal blood flow oxygenator (Bentley Univox, 1.8 m2), and an arterial filter (0.25 m2) and continued for 3 hr. Platelet kinetics, pooling, and counts were monitored by a Geiger probe and a Coulter counter. The thrombi in the oxygenator and arterial filter and emboli in viscera and brain were imaged with a gamma camera and measured with an ion chamber and gamma counter. Percentage of INPLT (mean +/- SD) in organs, tissues, and components of the circuit in four groups of pigs was calculated. Flow cytometry with antibodies to CD61 (GPIIIa) and CD62P (GMP-140: control) of porcine platelets was carried out with blood samples taken before, during, and after CPB for estimation of circulating platelet aggregates and platelet microparticles. Pulmonary, renal, cardiac, and cerebral emboli in pigs undergoing CPB with and without a filter were similar (p < 0.1). The amount of filter adherent thrombi was small (0.04 +/- 0.01%); oxygenator adherent thrombus in both groups was similar (p < 0.1). Emboli were found in the cerebral medulla, hippocampus, and posterior cerebral cortex in both groups. During CPB, the arterial filter functioned minimally as a trap for platelet thrombi detached from the oxygenator and circulating emboli. Flow cytometry of blood demonstrated the shift of equilibria from single platelets to platelet aggregates and microparticles during CPB and their gradual reversal to single platelets after CPB; the loosely adherent emboli disaggregated and further shifted these equilibria to single platelets and smaller aggregates, probably through the action of endogenous nitric oxide and prostacyclin. The emboli were trapped in organs and tissues and microparticles were sequestered by the reticuloendothelial system.

Reduction of neutrophil margination by L-arginine during hypothermic cardiopulmonary bypass in a pig model.

Nitric oxide generation by L-arginine (2 mg/kg/min) infusion during cardiopulmonary bypass (CPB) increases blood flow to all organs and reduces cytokine induced organ damage by reducing the level of marginating neutrophils (Ns). The N-trapping in the oxygenator (OX), arterial filter (AF), cardiotomy reservoir (CR), and N-margination were quantified with indium 111 labeled autologous neutrophils (INN) in nine groups of 40 Yorkshire pigs (30-35 kg). Cardiopulmonary bypass (180 min or 90 min CPB, 90 min reperfusion) was carried out at 2.5-3.5 L/min and at two temperatures (18 degrees C, 28 degrees C). The INN (650-780 microCi) was administered intravenously 15 mins before CPB. All pigs received heparin systemically (activated coagulation time > 400 secs); CPB was instituted with a roller pump, OX (Univox 1.8 m2), AF (0.25 m2), and CR (BCR-3500, Bentley Lab, Irvine, CA). The INN distribution in the device (OX, AF, CR) and organs was imaged with a gamma camera and measured with an ion chamber and a gamma counter. The LA infusion decreased N-trapping, estimated as the percent of injected INN (mean +/- standard deviation), in OX from control (2.7 +/- 2.02)% to (0.94 +/- 0.29)%, and margination in lung from control (48 +/- 4)% to minimal levels (23 +/- 2)% (p < 0.01). In the CPB reperfusion group, a beneficial effect was observed at LA low dose and toxicity of higher N-margination at 15 mg/ kg/min. Neither CPB temperature nor Leumedin affected N-margination significantly.

Efficient parathyroidectomy guided by SPECT-MIBI and hormonal measurements.

UNLABELLED: Parathyroidectomy is a difficult and lengthy operation which is noncurative in 6% to 10% of cases. To improve the efficiency of this operation, a new dual diagnostic approach was prospectively applied. METHODS: Preoperative tomographic 99mTc-sestamibi (MIBI) scintography and intraoperative measurements of circulating parathyroid hormone (PTH) levels by a quick assay (QPTH) were used. Scintigraphy comprised immediate and delayed planar and SPECT of the neck and chest, following 20 mCi MIBI. The presence and location of persistent foci of abnormal activity found within the neck mediastinum on volume-rendered reprojection (RPJ) of the SPECT data were reported. The surgion, guided by the three-dimensional MIBI-SPECT/RPJ images, identified and excised the single or most prominent scintigraphic focus and applied the QPTH. If PTH levels fell from baseline by at least 50%, the operation was concluded. RESULTS: The operative time of primary parathyroidectomy was reduced from an average of 90 min (before the introduction of scintigraphy and intraoperative PTH measurements) to 57 min. All but two patients became normocalcemic. In 58 consecutive patients with hyperparathyroidism, MIBI-SPECT/RPJ correctly and precisely identified 51 of 53 (96%) primary parathyroid adenomas, 14 to 15 secondary hyperplasias and 2 of 3 hyperplastic glands in MEN (sensitivity 94%, specificity 92%). QPTH verified the excision of the primary parathyroid adenomas and predicted normocalcemia in 50 of 52 patients. In 6 patients with misleading scintigraphy, QPTH was especially useful and guided the surgeon to continue the operation until the abnormal parathyroid tissue was found and excised. CONCLUSION: MIBI-SPEC/RPJ and QPTH sequentially applied improved the efficiency of parathyroidectomy.