Technetium-99m Red Blood Cell Research Articles

High-Resolution Splenic Imaging: [68Ga]Ga-Oxine Red Blood Cell PET/CT for Differentiation of Splenosis Mimicking Malignant Lymphoma

The differentiation of splenic tissue from malignant lesions via imaging may be challenging, particularly considering aberrant or accessory lesions and diseases that are rarely encountered. Functioning splenic tissue can be identified using technetium-99m red blood cell (99mTc-RBC) scintigraphy, but its sensitivity is limited and may not be available. We present the case of a patient in whom disseminated abdomino-pelvic splenosis was diagnosed using PET/CT with gallium-68-oxine-labeled RBCs. The method represents a feasible and probably superior alternative to splenic scintigraphy.

The application of technetium-99m-red blood cell scintigraphy in the diagnosis of orbital cavernous hemangioma.

ObjectiveThe purpose of this study was to evaluate the clinical value of technetium-99m-red blood cell (99mTc-RBC) scintigraphy in the diagnosis of orbital cavernous hemangioma (OCH).Patients and methodsForty-one patients with pathologically confirmed orbital mass, of which 10 were OCH, underwent 99mTc-RBC scintigraphy in this study. The scanning procedure included an initial perfusion phase, followed by an early and a delayed blood pool phase. All patients underwent ultrasonography and computed tomography (CT), and 15 patients also underwent MRI.ResultsAll 10 OCH patients had no abnormal findings on radionuclide angiographic images and early blood pool phase, but increased activity was found during delayed blood pool phase. All other non-OCH orbital tumours did not have this tracer pattern. The radioactivity ratios of tumour to nontumour were 2.96±0.05 and 1.14±0.25, respectively, which had a statistically significant difference (t=15.18, P<0.001). Although nine of 10 OCH patients were diagnosed correctly with one false-positive case using ultrasound, both CT and MRI could not provide a definitive diagnosis.Conclusion99mTc-RBC scintigraphy is a reliable and useful procedure for the diagnosis of OCH. It may be considered as one of the routine clinical screening tools for the diagnosis of OCH and as a complement investigation to ultrasonography and CT.

An Uncommon Cause of Abdominal Pain and Gastrointestinal Hemorrhage from Duodenal Perforation by an Inferior Vena Cava Filter

A 92-year-old female with a past medical history of pulmonary embolism on Coumadin status post retrievable inferior vena cava (IVC) filter placement in 2011 presented with hematochezia and abdominal pain. On arrival to the emergency department, the patient's hemoglobin was 6.4 G/DL (baseline of 11 G/DL) and INR of 3.8. Vital signs were intially stable on presentation and the patient developed hypotension with systolic blood pressure in the 90s. The patient was resuscitated with transfusion of packed red blood cells, platelets and plasma. Vitamin K was given for reversal of her coagulopathy. A technetium-99m red blood cell scintigraphy (bleeding scan) for evaluation of gastrointestinal hemorrhage was obtained that identified an area of active bleeding in the region of the small bowel. Following the positive scan, the patient subsequently underwent conventional angiography on two occasions; however, no therapeutic intervention could be performed, as the bleeding source could not be identified. CT angiography was obtained for ongoing abdominal pain and bleeding that demonstrated the infrarenal IVC filter struts extended beyond the lumen of the IVC, suspicious for perforation through the IVC wall. One strut of the IVC filter appeared to extend through the medial wall of the 2nd portion of the duodenum and into the duodenal lumen. We believe an open surgical approach for filter retrieval would have been the most effective intervention, however, given patient's advanced age, critical condition, and multiple co-morbidities the patient was enrolled in hospice care and eventually expired. In review of literature, overall IVC filter perforation incidence is reported at 0.2% and should be considered in patients with abdominal pain and evidence of bleeding. Intervention with surgical retrieval is reported to be successful in well-selected patients.Figure 1Figure 2Figure 3

Liposomal angiogenic peptides for ischemic limb perfusion: comparative study between different administration methods

Background: We investigated the therapeutic effectiveness of PEGylated liposomes loaded with angiogenic peptides for treating hindlimb ischemia.Methods: Rats received a femoral artery occlusion. Red blood cells collected from the animals were labeled with technetium-99m. Limb perfusion gamma imaging was performed. PEGylated liposomes loaded with angiogenic peptides were administered intra-arterially. Technetium-99m red blood cell imaging was repeated 1 week later. The animals were sacrificed the next day. The expression of angiogenic proteins was studied. Later, changes in limb perfusion after intra-arterial infusion versus intra-muscular injection were also compared to determine the therapeutic effectiveness of different administration methods.Results: Femoral artery occlusion dramatically reduced ischemic limb perfusion (by an average of 69%, compared to contralateral limb). This was not different among groups (p > 0.05). Liposomes loaded with angiogenic peptides significantly improved ischemic limb perfusion, compared to controls (210% of baseline, versus 100% of baseline in control; p < 0.05 versus controls). The enhanced ischemic limb perfusion was accompanied by an increased expression of CD 31 (an average of 1.6-fold increase of controls; p < 0.05). The liposomes or peptides treatment alone did not affect ischemic perfusion (liposomes alone: 100% of baseline; peptides alone: 120% of baseline; p > 0.05 versus controls, respectively) or the angiogenic response (1.1-fold of controls in liposomes alone; 1.0-fold of controls in peptides alone; p > 0.05 versus controls, respectively). Intra-muscular injection induced similar liposomal treatment effects on ischemic limb perfusion (230% of baseline) as those by intra-arterial infusion (210% of baseline; p < 0.05 versus intra-muscular).Conclusions: PEGylated liposomes loaded with angiogenic peptides improved ischemic limb perfusion and promoted angiogenic responses. Liposomal angiogenic treatment via intra-arterial infusion resulted in an equally effective therapeutic efficacy compared to that of intra-muscular injection. These results show the therapeutic potential of our liposomal strategy for treating peripheral limb ischemia.

A Study on Analysis of Labeling Efficiency Depending on Mixing Time in Asan Medical Center Red Blood Cell Labeling Method

ABSTRACT The aim of this study was to overcome the shortcomings of technetium-99m red blood cell labeling, such as the requirement of additional time, and to maintain a stable labeling efficiency by reducing the mixing time for technetium-99m red blood cell labeling in the Asan Medical Center red blood cell labeling method developed by this hospital. Thirty patients, who underwent an examination using technetium-99m red blood cell labeling in the nuclear medicine department from April to September 2012, were selected randomly. Blood samples (5 mL per patient) were mixed with acid citrate dextrose, and 1-mL aliquots were taken to make four blood samples. The Asan Medical Center red blood cell labeling method was used for labeling. In this case, the mixing time was set to 5, 10, 15, and 20 min before calculating the efficiency of each labeling. The difference depending on the mixing time was compared. According to the technetium-99m red blood cell labeling efficiency depending on the mixing time in the Asan Medical Center red blood cell labeling method, the efficiency of each labeling was 92 ± 5%, 96 ± 5%, 97 ± 5%, and 98 ± 5% for 5, 10, 15, and 20 min, respectively. Overall, the labeling efficiency was relatively low when the mixing time was 5 min, whereas there was no significant difference in labeling efficiency when the mixing time was longer than 5 min. In conclusion, the Asan Medical Center red blood cell labeling method can provide an environment that is more conducive to the combination of red blood cell with technetium-99m pertechnetate than the previous modified labeling method because the Asan Medical Center red blood cell labeling method removes blood plasma in an additional centrifugation process.

Application of the R0-R3 formulas using the ECToolbox software to calculate left ventricular ejection fraction in myocardial perfusion SPET and comparison with equilibrium radionuclide ventriculography. Normal cutoff values for a Chinese population.

The aim of this study was to compare the correlation and consistency of left ventricular ejection fraction (LVEF) obtained by ECG-gated myocardial perfusion SPET (GMPS) using the four formulas (R0-R3) in ECToolbox software and by equilibrium radionuclide ventriculography (ERNV), and determine the optimal diagnostic thresholds of the four formulas in a Chinese population. A hundred and three candidate donors (59 male and 44 female), including 38 patients with a history of myocardial infarction and 65 patients with suspected coronary heart disease, underwent both (99m)Tc-MIBI rest GMPS and technetium-99m red blood cells ((99m)Tc-RBC) ERNV within a week. The LVEF values calculated by ECToolbox R0, R1, R2 and R3 were compared with those obtained by ERNV. Using LVEF≥50% obtained by ERNV as the gold standard, the optimal diagnostic thresholds of the four formulas (R0-R3) were assessed by receiver operating characteristic (ROC) curves. Results showed that the mean LVEF value of ERNV was 54.6±17.5%, and the mean LVEF value of the four formulas was 64.1±15.7%, 56.3±15.1%, 69.9±17.9% and 56.3±13.6%, respectively, showing a significantly strong correlation between the results obtained by the two methods (r>0.85, P<0.001). All mean LVEF values obtained by the four formulas were higher than the mean LVEF value obtained by ERNV, and there was very significant difference between R0 and R2 results and the ERNV result (t=12.511 and 18.652, P<0.001). Furthermore, there was significant difference between R1 and R3 results and the ERNV result (t=2.169 and 2.570, P<0.05). Using ERNV LVEF≥50% as the normal diagnostic value, the optimal diagnostic threshold of R0∼R3 was 56.5%, 51.5%, 64.5% and 52.5%, respectively. There was a strong correlation between the LVEF values obtained by the four formulas in ECToolbox software and ERNV, but the numerical values of LVEF differed between the four formulas. In conclusion, A strong correlation was observed among R0, R1, R2 and R3 in the ECToolbox software when compared with ERNV and also between them for the assessment of LVEF. However, there were some differences in the numerical values of LVEF generated by the individual formulas, which must be taken into account in comparing clinical studies.

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Jejunal Amyloidosis: A Rare Cause of Severe Gastrointestinal Bleeding

1Department of Medicine; 2Division of Pathology; 3Division of Gastroenterology, University of British Columbia, Royal Columbian Hospital, New Westminster, British Columbia Correspondence: Dr Justin Cheung, Department of Gastroenterology, Royal Columbian Hospital, 410-301 East Columbia Street, New Westminster, British Columbia V3L 3W5. Telephone 604-525-0155, fax 604-525-1699, e-mail justa48@hotmail.com Received for publication December 22, 2011. Accepted December 29, 2011 CASE PRESENTATION An 81-year-old Jamaican woman presented with melena and severe anemia, and a hemoglobin level of 47 g/L (normal range 115 g/L to 160 g/L). A gastroscopy and colonoscopy were negative for any lesions. Duodenal biopsies were normal. A subsequent computed tomography scan of the abdomen with contrast showed diffuse thickening from the jejunum to the distal small bowel and a small area of active bleeding in the mid small bowel. A technetium-99m red blood cell scan demonstrated active bleeding in the proximal jejunum. Push enteroscopy (120 cm to 150 cm below incisor) revealed mild diffuse friability starting from the proximal jejunum, as well as erosions, nodularities, polypoid protrusions and valvulae conniventes thickening in the remaining jejunum (Figures 1A and 1B). Jejunal biopsies showed extensive amyloid deposition in the lamina propria and submucosa, with Congo red stain demonstrating apple-green birefringence under polarized light (Figure 2), and hematoxylin counterstain revealing amorphous, salmon-pink, sparsely cellular hyaline material (Figure 3). Serum protein electrophoresis, immunofixation and a serum-free light chain assay confirmed the presence of monoclonal immunoglobulin G lambda paraprotein. The patient was transfused with packed red blood cells as needed (average one unit per day), and treated with bortezomib and dexamethasone for primary amyloidosis. By day 17 of hospitalization, the bleeding had resolved and the patient was subsequently discharged without any further bleeding episodes. DISCUSSION Amyloidosis is a multisystem disease characterized by extracellular deposition of abnormal protein fibrils in various tissues and organs. The protein fibrils are derived from monoclonal immunoglobulin light chains in primary amyloidosis (AL), acute phase reactant serum amyloid A in secondary amyloidosis (AA), and beta2-microglobulin in dialysis-related amyloidosis (Ab2m). Clinical manifestations in amyloidosis are variable, but the heart and kidneys are most commonly involved. Gastrointestinal symptoms due to bleeding, dysmotility and malabsorption are present in up to 60% of AA (1), but in only 1% of AL (2). The diagnosis of amyloidosis can only be confirmed by tissue biopsy because endoscopic and radiologic findings are nonspecific. Therapy is directed at the underlying cause in AL (plasma cell dyscrasia) and AA (infection, inflammation and malignancy), whereas treatment in Ab2m involves alteration of dialysis mode or consideration of renal transplantation (3). Severe gastrointestinal bleeding rarely occurs as the sole or initial manifestation of systemic amyloidosis (4). Mechanisms by which hemorrhage occurs in gastrointestinal amyloidosis have been postulated, including intestinal ischemia, necrotic ulceration, mucosal tearing, vascular fragility, abnormal platelet aggregation, and factor IX and X deficiencies (5,6). In addition to supportive care for bleeding, treatment must be tailored to the specific type of amyloidosis, as determined by endoscopy and histology. Endoscopy classically shows polypoid protrusions and valvulae conniventes thickening in AL; a imAge of the month

A Role for Subtraction Scintigraphy in the Evaluation of Lower Gastrointestinal Bleeding in the Athlete

While lower gastrointestinal haemorrhage (LGIH) in the athlete tends to be self-limiting in the majority of athletes, recurrent symptoms occur in some athletes. It is important to identify the smaller percentage of athletes in whom risks and recurrence are greater because both their general health and athletic performance might benefit from more rigorous clinical evaluation. Technetium-99m red blood cell ((99m)Tc RBC) scintigraphy is a technique for detection and localisation of LGIH and offers a number of significant advantages over other imaging modalities in the evaluation of LGIH. Nonetheless, there are a number of limitations recognised in (99m)Tc RBC scintigraphic evaluation of LGIH. Subtraction scintigraphy in (99m)Tc RBC evaluation of gastrointestinal haemorrhage may offer a tool to overcome limitations of conventional scintigraphy. In essence, subtracting a nominal 'mask' or reference image from all subsequent images provides a mechanism to view only the information contributed by accumulated bleeding, removing potential sources of both false-positive and false-negative findings. While the limitations of procedures available for the evaluation of LGIH are generally prohibitive of effective application in the obscure bleeding associated with athletic performance, adopting subtraction methods in conjunction with conventional (99m)Tc RBC scintigraphy may offer a valuable tool in identification and localisation of bleeding sites. The general health and athletic performance may be enhanced in some athletes when the underlying cause of bleeding can be more appropriately managed.

Evaluation of active bleeding into hematomas by technetium-99m red blood cell scintigraphy before angiography.

To evaluate the utility of technetium-99m red blood cell (Tc-99m RBC) scintigraphy in the diagnosis of active hemorrhage into large intra-abdominal hematomas before arteriography. This retrospective case series describes four patients (1 man and 3 women) with large abdominal wall and retroperitoneal hematomas confirmed by computed tomography who underwent Tc-99m RBC scintigraphy before angiography. Arterial transcatheter embolization was performed if active hemorrhage was found. Three of the patients had positive findings on Tc-99m RBC scans, which showed spreading of the labeled erythrocytes into the hematoma space. Positive scintigraphy was diagnostic for active hemorrhage and helped localize the bleeding sites. Angiography confirmed the diagnosis in all patients with positive scintigraphy and ruled out active bleeding in the patient with a negative Tc-99m-labeled RBC scan. Tc-99m RBC scintigraphy appears to be sensitive and accurate in detecting active hemorrhage into intra-abdominal hematomas.

Automatic quantification of left ventricular ejection fraction from gated blood pool SPECT

Background. Cardiac gated blood pool single photon emission computed tomography (GBPS) better separates cardiac chambers compared with planar radionuclide ventriculography (PRNV). We have developed a completely automatic algorithm to measure quantitatively the left ventricular ejection fraction (LVEF) from gated technetium 99m-red blood cells (RBC) GBPS short-axis 3-dimensional image volumes. Methods and Results. The algorithm determines an ellipsoidal coordinate system for the left ventricle and then computes a static estimate of the endocardial surface by use of counts and count gradients. A dynamic surface representing the endocardium is computed for each interval of the cardiac cycle by use of additional information from the temporal Fourier transform of the image data sets. The algorithm then calculates the left ventricular volume for each interval and computes LVEF from the end-diastolic and end-systolic volumes. The algorithm was developed in a pilot group (N = 45) and validated in a second group (N = 89) of patients who underwent PRNV and 8-interval GBPS. Technically inadequate studies (N = 38) were rejected before grouping and processing. Automatic identification and contouring of the left ventricle was successful in 121 172 patients (70%) globally and in 76 89 patients (85%) in the validation group. Correlation between LVEFs measured from GBPS and PRNV was high (y = 2.00 + 1.01x, r = 0.89), with GBPS LVEF significantly higher than PRNV LVEF (average difference = 2.8%, P < .004). Conclusions. Our automatic algorithm agrees with conventional radionuclide measurements of LVEF and provides the basis for 3-dimensional analysis of wall motion.

Radioimmunoscintigraphy in the differential diagnosis of hepatic mass lesion

A patient with suspected recurrent cancer of the colon underwent a variety of imaging procedures for the differential diagnosis of a hepatic mass lesion. Computed tomography (CT) showed a low-density lesion in the left hepatic lobe, and the initial CT-guided biopsy of the liver mass was reported to demonstrate a benign lesion. Ultrasonography (US) showed a hypoechoic lesion, and technetium-99m red blood cell (RBC) scan failed to suggest a hemangioma. However, radioimmunoscintigraphy (RIS) using 99mTc- labeled anti-carcinoembryonic antigen (CEA) monoclonal antibody clearly demonstrated increase uptake of antibody in the liver lesion. Scheduled hepatic angiography was canceled and subsequent exploratory laparotomy confirmed liver metastasis. RIS appears most helpful in the diagnosis of hepatic metastasis in patients with colorectal cancer and a rising CEA level. CT, US, and 99mTc-RBC studies for the investigation of hepatic masses are briefly discussed.

Intrahepatic, extramedullary hematopoiesis mimicking hemangioma on Technetium-99m red blood cell SPECT examination

Cavernous hemangiomas are the most common lesion of the liver. Because of the risk of hemorrhage inherent in percutaneous biopsy of such lesions, noninter-ventional modalities (such as CT, ultrasound, MRI and Technetium-99m red blood cell imaging) have been utilized for differentiating them from other lesions. The sensitivities and specificities of these techniques vary greatly. Technetium-99m red blood cell imaging with planar and SPECT imaging has been shown to have an overall sensitivity of 89%, a specificity of 100%, and an overall accuracy of 92%. Despite its high accuracy, rare false positives have been reported with Technetium-99m red blood cell imaging with SPECT. Review of the literature indicates four cases of hepato-cellular carcinoma, one case of hepatic angiosarcoma, and one case of hepatic metastases from colorectal carcinoma as having an appearance identical to hemangioma with this modality. We present an additional false positive of a focal region of intrahepatic extramedullary hematopoiesis in a patient with Gaucher's disease as having an appearance on Technetium-99m red blood cell imaging with SPECT identical to that of hemangioma.

Head-up tilt and hemodynamic changes during orthostatic hypotension in patients with supine hypertension

Objectives. This study assessed the mechanism(s) of the decrease in upright blood pressure in patients with supine hypertension by using the tilt test and a hemodynamic approach.Background. Orthostatic hypotension in patients with supine hypertension creates a pathophysiologic and therapeutic dilemma.Methods. We studied 28 consecutive patients with history of orthostatic intolerance amounting to recurrent syncope in 13 of them (15 men, 13 women; mean [SD] age 65 ± 11 years). They all had supine hypertension (systolic blood pressure >160 mm Hg) and orthostatic hypotension (found to be a decrease in systolic blood pressure >30 mm Hg during tilt test). Cardiac output, and orthostatic hypotension (found to be a decrease in systolic radionuclide first-pass technique (technetium-99m red blood cell tagging). Total blood volume was determined by radioiodinated serum albumin, and the ratio of cardiopulmonary to total blood volume was used as an index of venous capacitance.Results. Twenty-one patients had accentuated venous pooling defined as a tilt-induced decrease in cardiopulmonary volume/ total blood volume ratio >15% from baseline or a supine ratio < 14% (normal 16% to 18%), or both. Seven of the 28 patients had autonomic insufficiency; 6 of the 7 also had venous pooling; 1 patient had autonomic insufficiency only. Neither clinical history nor changes during tilt differentiated the subgroups. Plasma catecholamine levels increased during head-up tilt in all subgroups, and differences in their increase were not significant between patients with venous pooling and those with autonomic insufficiency. However, radionuclide hemodynamic variables revealed that patients with venous pooling compensated for the decrease in stroke volume by increasing peripheral resistance, whereas patients with autonomic dysfunction did not.Conclusions. Orthostatic hypotension in patients with supine hypertension may have multiple etiologies. Hemodynamic assessment with determination of cardiopulmonary volume and systemic vascular resistance differentiated between venous pooling and autonomic insufficiency in these patients; head-up tilt and plasma catecholamine levels did not. These findings may have important therapeutic implications.

Hepatic hemangioma in cirrhotics with portal hypertension: evaluation with Tc-99m red blood cell SPECT.

To determine whether extensive shunting associated with portal hypertension (PH) adversely affects the diagnostic accuracy of technetium-99m red blood cell (RBC) single photon emission computed tomography (SPECT) for hepatic hemangioma (HH). Nineteen possible HHs (1.0-11.0 cm in diameter) in 15 cirrhotics with PH were studied with RBC SPECT. RBC SPECT allowed correct categorization of four HHs (1.5, 2.8, 4.0, and 4.0 cm in diameter) and 13 non-HHs (1.5-11.0 cm in diameter). Two small HHs (1.0 and 1.4 cm in diameter) were "missed." Sensitivity, specificity, and accuracy were 67%, 100%, and 89%, respectively. Despite abnormal liver blood flow dynamics due to portosystemic collateralization, RBC SPECT allows reliable identification of HH in cirrhotics with PH. As in noncirrhotics, its major limitation is small lesion size.

Poor-quality red blood cell labelling with technetium-99m: case report and review of the literature

Technetium-99m red blood cell (RBC) venography is a simple and sensitive technique for the diagnosis of deep vein thrombosis of the lower limb, but optimal labelling of the blood pool is essential for a diagnostic study. Here we report the case of a 44-year-old male with deep vein thrombosis of the right leg. RBC venography of the lower extremities showed poor labelling. In addition we review the literature on the subject.

Photopenic appearance of the hepatic lesion (s) on technetium-99m red blood cell imaging

A 63-YEAR-OLD MAN with a history of ethanol and tobacco abuse complained of indigestion, heartburn, and dyspepsia. In 1974, he underwent liver biopsy; acute alcoholic hepatitis with cirrhosis was diagnosed. A physician examination showed an enlarged liver palpable 14 cm below the right costal margin with tenderness, engorgement of the superficial abdominal wall veins, and shifting dullness, indicating ascites. Palmar erythema and mild pitting edema in the lower extremities were also present. A computed tomography (CT) scan of the abdomen showed a large, low-density lesion in the central portion of the right lobe of the liver (Fig 1). Since he was scheduled to undergo biopsy of this lesion, the patient was referred for technetium-99m red blood cell (99mTc-RBC) liver imaging to rule out a hemangioma. The study showed hepatomegaly with a photopenic area (Fig 2) corresponding to the lesion on the CT seen in immediate, 15-minute, 30minute, 1-hour, and 3-hour images, consistent with avascular mass or tumor mass undergoing necrosis. Alpha-fetoprotein was 12,000 nL/L (N = < 10 ng/L) and hepatitis B surface anti-

Technetium-99m radiocolloid scintigraphy, planar and SPECT red blood cell imaging and ultrasonography in diagnosis of hepatic hemangioma.

Technetium-99m planar sulfur colloid scintigraphy, red blood cell imaging and ultrasonography were performed in eighteen patients of hepatic hemangioma to evaluate their diagnostic utility. Radiocolloid scans detected fourteen hemangiomas in 12 patients as focal hepatic defects but missed 9 lesions smaller than 2.5 cm in the other 6 patients, accounting for a 61% sensitivity. All 23 lesions were avascular or normovascular on radionuclide flow study. Serial planar red blood cell scintigraphy showed characteristic gradually increasing focal isotopic accumulation in the 14 hemangiomas which had identifiable cold areas on the radiocolloid study. One of 6 patients with normal radiocolloid scan also showed the typical increasing blood pool pattern of hemangioma, five had normal planar scans till 1 1/2 hours. SPECT red blood cell imaging in these 5 patients detected an additional seven hemangiomas. All 7 lesions were smaller than 2.5 cm. One 1.5 cm hemangioma was missed on both planar and SPECT red blood cell imaging. Region of interest ratios in SPECT transaxial images confirmed gradually increasing concentration of labeled red blood cells in the lesions. Ultrasonography detected 22 of the 23 hemangiomas. Ten were hyperechoic, average size 2.25 cm. Twelve were of mixed pattern, generally larger, average size 7.2 cm. Sonography is useful in the detection of hepatic hemangiomas as a focal mass lesion, but the variable sonographic appearance precludes a definite pathological diagnosis. Technetium-99m red blood cell imaging appears a sensitive technique in detection of hepatic hemangioma, with SPECT being especially useful in locating smaller lesions. The addition of useful in locating smaller lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Technetium-99m red blood cell labeling in patients treated with doxorubicin.

Radionuclide angiography is useful in monitoring cardiotoxicity of doxorubicin, but in vivo RBC labeling in these patients is believed to be poorer than that in general patients. The left ventricle-to-background activity ratio (R) was not significantly lower in patients treated with doxorubicin (3.24 +/- 1.15, N = 13) than in control patients (3.89 +/- 1.60, N = 14). With both modified in vivo and in vitro labeling, R was significantly improved in patients treated with doxorubicin (4.37 +/- 0.91, N = 8, and 4.37 +/- 1.22, N = 13, respectively). However, with the modified in vivo method, labeling efficiency remained a function of hematocrit, whereas the in vitro method removed this dependency. Both modified in vivo and in vitro labeling result in improved image quality over in vivo labeling in patients treated with doxorubicin, and the choice of method can be based on other factors.

Technetium-99m red blood cell venography of the lower limb in symptomatic pulmonary embolization.

Tc-99m RBC venography of the legs was obtained in 42 patients with primary pulmonary symptomatology and a diagnosis of pulmonary embolization. In 31 of these 42 patients (74%), the nuclear venogram revealed the presence of deep vein thrombosis (DVT) and a source of embolization. Of the 31 patients with leg DVT documented by venography, 13 (42%) showed thrombosis confined to the calf. Clinical findings suggested that only 20 of the 31 patients (65%) with DVT could have harboured a source of embolization in the legs. Tc-99m RBC venography is a useful noninvasive test for the global and comprehensive assessment of patients with symptomatic pulmonary embolization.