Tc-99m sulfur colloid and Tc-99m tagged red blood cell methods are comparable for detecting lower gastrointestinal bleeding in clinical practice

PURPOSE: The objective of this study was to determine whether the Tc-99m red blood cells (Tc-99m RBC) method has a true advantage over the Tc-99m sulfur colloid (Tc-99m SC) technique in a busy clinical practice for detecting and localizing lower gastrointestinal bleeding sites. METHODS: Three hundred fifty-nine consecutive gastrointestinal bleeding studies performed during the past 4 years were reviewed retrospectively. One hundred ninety-three scans were obtained with Tc-99m SC (scan duration, 30 minutes) and 138 studies were performed after the administration of Tc-99m RBC (scan duration, 1 hour). In addition, 28 examinations with Tc-99m SC were followed immediately by Tc-99m RBC scans for a duration of several hours. The results of the two methods were analyzed and the performance of the two techniques was compared. RESULTS: Among 193 scans performed using the Tc-99m SC method, 47 (24.4%) successfully identified the location of the bleeding site, whereas in 138 scans performed using Tc-99m RBC, 38 (27.5%) were successful for this purpose. In the remaining 28 scans in which the Tc-99m SC scan was followed by the Tc-99m RBC study, only 4 (14.3%) positive bleeding sites were identified after a prolonged imaging period. DISCUSSION: The theoretical advantages of the Tc-99m RBC technique compared with the Tc-99m SC method cannot be substantiated by this study. Our findings suggest that the efficacy of these two methods is nearly equal at a practical level. CONCLUSION: The simpler and cost-effective Tc-99m SC method is as efficient as the Tc-99m RBC method when the scanning time is limited to 1 hour and optimal imaging and interpretation schemes are used.     

Radionuclide imaging of a rectus sheath hematoma caused by insulin injections

CT scanning, MRI, and ultrasonography are the imaging procedures of choice for the study of rectus sheath hematomas. A rectus sheath hematoma was evaluated scintigraphically after the intravenous administration of Tc-99m labeled RBC, which confirmed the hematoma, demonstrated the sites of bleeding, and revealed continued bleeding.     

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

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Tc-99m RBC scintigraphy appears to be sensitive and accurate in detecting active hemorrhage into intra-abdominal hematomas.     

Scintigraphic diagnosis of polysplenia in the adult

PURPOSE: The authors describe an adult patient with low index of suspicion for polysplenia. The diagnostic contribution of various investigative modalities is considered, and the key role of scintigraphy is specifically highlighted. RESULTS: CT scan findings revealed multiple abdominal and retroperitoneal masses. Needle biopsy of a flank mass was nonspecific. Tc-99m sulfur colloid liver spleen scintigraphy and Tc-99m heat-denatured RBC scans showed the presence of polysplenia. CONCLUSIONS: Multiple spleens can be mistaken for abdominal neoplasms on CT. Biopsy results may not always be helpful. In patients in whom there is such a diagnostic dilemma, Tc-99m heat-denatured RBC scans can successfully establish the definitive diagnosis of polysplenia.     

Effect of stannous pyrophosphate red blood cell gastrointestinal bleeding scan on subsequent Meckel's scan.

Both labeled RBC and Meckel's scans have been used to evaluate pediatric patients with gastrointestinal bleeding, sometimes sequentially in the same patient. Particularly in infants, from whom withdrawal of sufficient blood for in vitro RBC labeling is often not possible, in vivo labeling with stannous pyrophosphate is used. However, prior administration of stannous-containing agents is known to alter the in vivo distribution of Tc-99m pertechnetate and to interfere with the subsequent Meckel's scan. The authors report on a Meckel's scan performed on an infant 1 week after a GI bleeding study with Tc-99m and stannous pyrophosphate. The Meckel's scan shows abnormal tracer distribution with absent gastric uptake, rendering the scan uninterpretable. In pediatric patients with gastrointestinal bleeding, a Meckel's scan should be done before labeled RBC imaging.     

Comparison of technetium-99m sulfur colloid and in vitro labeled technetium-99m RBCs in the detection of gastrointestinal bleeding

Twenty-seven paired Tc-99m sulfur colloid (SC) and Tc-99m RBC studies were evaluated for the detection of GI bleeding. The only two positive Tc-99m SC studies had positive early Tc-99m RBC studies as well. There were 15 other positive Tc-99m RBC studies (three during the first hour) and these were associated with normal Tc-99m SC scans. Approximately 70% of the positive Tc-99m RBC studies occurred after 1 hour. Tc-99m RBCs should be the initial test in patients with GI bleeding.     

Meckel's diverticulum findings on Tc-99m red blood cell scintigraphy in a bleeding leukemic patient confirmed by Tc-99m pertechnetate scintigraphy

A 25-year-old Caucasian woman with a medical history of acute promyelocytic leukemia presented to the emergency department with massive gastrointestinal bleeding. A bone marrow biopsy excluded hemorrhagic leukemia. Esophagogastroduodenoscopy, colonoscopy, emergency abdominal angiography, abdominal CT scan, and wireless capsule endoscopy were performed but no source of bleeding could be detected. Tc-99m RBC scintigraphy was consistent with a small bowel bleeding focus. The persistent and focal images in the right abdomen were suggestive of Tc-99m RBC trapping in the lumen of a Meckel diverticulum (MD). In accordance with this suspicion, successive Tc-99m pertechnetate scintigraphy was performed after 3 days, consistent with the diagnostic hypothesis. Due to the persisting severe bleeding (with a drop in baseline hemoglobin from 10.4 to 7.1 g/dL), despite 8 units of blood transfusion, emergency surgery was performed. Through a minilaparotomy a segmental small bowel resection, including Meckel diverticulum, was performed. The postoperative course was uneventful.     

Gallbladder visualization during technetium-99m RBC blood pool imaging. Case report and literature review

Gallbladder visualization occurred after a Tc-99m red blood cell (RBC) cardiac gated blood pool scan. To date, seven cases of gallbladder visualization after the intravenous injection of Tc-99m RBCs have been reported. In the previous six patients the gallbladder was visualized incidentally during a search for gastrointestinal (GI) bleeding. All of the patients were anemic, six of seven had chronic renal failure, and five of seven had received multiple blood transfusions. When interpreting GI bleeding scans in patients with anemia and renal failure, awareness of the possibility of gallbladder visualization in the delayed images is important to avoid false-positive results.     

Uncommon scintigraphic findings of multiple hepatic hemangiomas

Tc-99m labeled red blood cell scintigraphy is a valuable, noninvasive technique for differentiating hepatic hemangioma from other lesions by demonstrating a "perfusion blood pool mismatch." The characteristic finding on dynamic CT scan of peripheral and subsequent central enhancement is not usually seen on Tc-99m RBC angiography, probably due to rapid mixing and dilution of the radionuclide and low resolution of the gamma camera. A case of multiple hepatic hemangioma is presented in which Tc-99m RBC dynamic angiography demonstrated peripheral enhancement with subsequent central filling. In addition, delayed static images showed more hepatic lesions.     

Technetium-99m labeled red blood cells in the evaluation of hemangiosarcoma

Imaging with Tc-99m labeled red blood cells (RBC) is increasingly being used in the detection of acute gastro-intestinal bleeding, especially in patients with intermittent bleeding. A patient is presented in whom the labeled RBC scan was helpful in the incidental discovery of a previously unsuspected probable angiosarcoma of the right femur and adjacent soft tissues of the right hip due to the "blood pool" or "blush effect" of the labeled cells. The labeled RBC scan also identified extravasation due to active gastrointestinal bleeding from a previously unknown angiosarcoma of the ascending colon. Thus, the Tc-99m labeled RBC scan was useful in simultaneously detecting extravasation and blood pool effect at two remote tumor sites in the same patient.     

Technetium-99m labeled RBC imaging in gastrointestinal bleeding from gastric leiomyoma

Tc-99m labeled RBC imaging is becoming increasingly useful in detecting gastrointestinal (GI) bleeding sites. A patient is presented who had massive GI bleeding from an unsuspected gastric leiomyoma in whom a Tc-99m sulfur colloid GI bleed image was negative. The Tc-99m labeled RBC imaging done on the day after sulfur colloid imaging revealed increased gastric activity due to active bleeding from an intragastric leiomyoma. Tc-99m labeled RBC imaging helped in early detection of the bleeding site resulting in its successful treatment. This experience also reinforces the assertion that Tc-99m labeled RBC imaging may be more helpful than Tc-99m sulfur colloid imaging in patients with upper GI or intermittent bleeding.     

Regional radioactivity discrepancy between Tc-99m GSA and Tc-99m phytate liver scans in a patient with massive hepatic necrosis

A 22-year-old woman with severe acute hepatitis underwent a Tc-99m galactosyl human serum albumin (GSA) scan. Intense accumulation was observed in the cephalic region of the right hepatic lobe, whereas the accumulation was reduced in the left lobe and the caudal region of the right lobe. A computed tomographic (CT) scan showed that the left lobe and the caudal region of the right posterior segment had atrophied and become hypodense, which were thought to represent postnecrotic scarring after massive hepatic necrosis. The relatively hyperdense region in the right lobe was slightly swollen and was thought to represent regenerating liver tissue or a "potato liver." Compared with the CT, the regions of elevated Tc-99m GSA accumulation correlated well with the areas of regenerating liver tissue, and the regions with reduced accumulation corresponded closely with the areas of postnecrotic scarring. On a Tc-99m phytate scan, unlike the Tc-99m GSA scan, the radiocolloid accumulation was intense in the left lobe and caudal region of the right lobe and reduced in the cephalic region of the right lobe. Together, the Tc-99m GSA scan and the Tc-99m phytate scan formed a set of exact "nega-posi" images. Biopsy specimens obtained during laparoscopy showed a few hepatocyte columns in the postnecrotic scarred left lobe. Severe disruption of the hepatocytes, prominent inflammatory cell infiltration, and obvious Kupffer cell hypertrophy and clustering were also observed.     

Intraperitoneal bleeding demonstrated by Tc-99m labeled red blood cell scintigraphy.

Tc-99m RBC scintigraphy is known to be useful for the evaluation of gastrointestinal bleeding. The authors describe a patient with a posttraumatic peritoneal tap in whom Tc-99m RBC imaging showed bleeding into the gastrointestinal wall and into the ascitic fluid.     

Skull base involvement by a nasopharyngeal carcinoma shown by Tc-99m MDP SPECT but not by computed tomography

PURPOSE: Plain radiographs, computed tomography (CT), and more recently magnetic resonance imaging (MRI) are used routinely to stage carcinoma of the nasopharynx. Tc-99m methylene diphosphonate (MDP) SPECT is seldom used for local staging of the disease. MATERIALS AND METHODS: Plain radiographs and CT were used to stage squamous carcinoma of the nasopharynx in a 50-year-old man with a left XII nerve palsy. RESULTS: Findings of the plain radiographs were normal, whereas the CT scan revealed a nonhomogenous hyperdense mass in the nasopharynx but intact underlying bone. Given the symptoms, a Tc-99m MDP planar scan was ordered and showed no enhanced uptake, but SPECT images obtained at the same time revealed markedly increased focal radiotracer uptake in the region of the tumor, indicating osseous involvement. CONCLUSION: Possible bony invasion with a nasopharyngeal carcinoma may be better shown with MDP SPECT than with planar isotope bone scans, plain radiographs, or CT.     

The value of Tc-99m red blood cell SPECT in differentiating giant cavernous hemangioma of the liver from other liver solid masses

PURPOSE: Giant cavernous hemangioma (GCH) of the liver has the potential risk for rupture and bleeding, which may cause sudden death. The purpose of this retrospective study was to compare the value of Tc-99m-labeled red blood cell (RBC) SPECT with ultrasound (US) in differentiating GCH from other solid liver masses. METHODS: Twenty-two patients with giant solid liver masses, equal to or greater than 8 cm in at least one dimension, identified by US were examined by Tc-99m RBC SPECT. Final diagnoses were based on findings of surgery, biopsy or follow-up by US for a minimum of 24 months after the scan. RESULTS: In all, US detected 23 giant liver masses in 22 patients (3 men, 19 women). Eighteen GCHs were detected in 17 patients by Tc-99m RBC SPECT. Nine showed a homogeneously increased blood pool; 9 revealed peripheral high, but central low, uptake. The US patterns in these 18 GCHs were mixed-echoic in 12, hyperechoic in 4, and hypoechoic in 2. The other five large liver tumors, all proved by operation, had no increased uptake area with Tc-99m RBC SPECT. The US patterns of these were mixed-echoic in 3, hyperechoic in 1, and hypoechoic in 1. CONCLUSIONS: Our study showed that there was no specific US pattern that would differentiate GCHs from other giant liver masses. Tc-99m RBC SPECT appeared to separate them clearly.     

Assessment of viable splenic tissue in massive splenic infarction with a Tc-99m heat-damaged RBC scan

A 59-year-old man with essential thrombocytosis was examined for abdominal pain. Splenic infarction was diagnosed on a computed tomographic scan. The Tc-99m heat-denatured RBC scan showed viable splenic tissue that was not evident on the computed tomographic scan or Tc-99m sulfur colloid scintigraphy.     

Jejunal leiomyosarcoma detected by Tc-99m sulfur colloid gastrointestinal bleeding scan

Jejunal leiomyosarcoma was initially detected in a patient by a gastrointestinal bleeding scan with Tc-99m sulfur colloid (SC). The scan showed increased blood flow and delayed persistent accumulation of radiotracer in the tumor. The Tc-99m SC gastrointestinal bleeding scan provided useful information to help determine the differential diagnosis of gastrointestinal tumor with bleeding.     

Renal cell carcinoma detected on Tc-99m-labeled red blood cell imaging

A 61-year-old-man with persistent anemia was referred for a Tc-99m-labeled red blood cell (RBC) scan to detect any source of gastrointestinal bleeding. RBC scintigraphy revealed a hypervascular mass in the left renal fossa with functional loss in that kidney, suggesting the possibility of a renal cell carcinoma (RCC). Computed tomography confirmed this. Most RCC tumors are hypervascular on conventional angiography, with a maximum incidence in men in the sixth decade. The incidental diagnosis of RCC during radionuclide imaging has been documented in previous reports, but the authors are not aware of any case of RCC diagnosed during a RBC scan. This case illustrates the importance of careful attention to the appearance of the kidneys on radionuclide scans. Noticeable asymmetric renal activity in a patient without known renal parenchymal disease warrants further investigation.     

Attempts at clarification of splenic visualization on reticuloendothelial images: Tc-99m DISIDA compared with heat- denatured Tc-99m RBC imaging

Four patients with enlarged left hepatic lobes and questionable or difficult splenic visualization on Tc-99m sulphur colloid (SC) images were further examined with additional radionuclide procedures. All four patients had Tc-99m DISIDA imaging, and three of them also had heat-denatured Tc-99m RBC imaging. The hepatobiliary images appear very effective in confirming postsplenectomy expanded enlargement of the left lobe of the liver and in refuting the presence of spleen in such cases. However, distinct visualization of the spleen in these patients can be achieved only through selective spleen imaging with heat-damaged red cells.     

Incidental detection of gastrointestinal stromal tumor by Tc-99m MDP bone scan

This case demonstrates extraosseous 99m-technetium methylene diphosphonate (Tc-99m MDP) accumulation from a gastrointestinal stromal tumor. A 75-year-old woman underwent a temporal bone CT for conductive hearing loss that showed sclerosis in the right occipital condyle. Follow-up Tc-99m MDP bone scan for osseous metastases instead showed a mass-like extraosseous accumulation of Tc-99m MDP in the anterior left upper quadrant. Differential diagnoses included gastric cancer, lymphoma, metastatic melanoma, systemic hypercalcemia, or heterotopic mesenteric ossification. Contrast CT showed a well-circumscribed mass arising from the stomach, and subsequent pathology confirmed gastrointestinal stromal tumor. These tumors rarely can contain osteoclast-like giant cells and should be considered for extraosseous Tc-99m MDP accumulation.