Tc-99m-labeled somatostatin receptor-binding peptide imaging for a pulmonary nodule

A 76-year-old man with chronic obstructive pulmonary disease and a smoking history had a 2-cm solitary pulmonary nodule that was likely to be malignant. He underwent Tc-99m-labeled somatostatin receptor-binding peptide SPECT. A computed tomographic-guided transthoracic needle biopsy performed before the SPECT was nondiagnostic. SPECT showed increased uptake of the tracer by the nodule, which was subsequently found to be adenocarcinoma by surgical resection. Differentiation of malignant from benign nodules by Tc-99m-labeled somatostatin imaging may be a reasonable approach in patients at high risk for cancer and concurrently at increased risk for complications from invasive diagnostic procedures or surgical resection.     

Scintigraphic diagnosis of intrathoracic extramedullary hematopoiesis in a patient with β-thalassemia

We report the scintigraphic diagnosis of intrathoracic extramedullary hematopoiesis (EMH) in a patient with β-thalassemia. A patient had a mass in the right thoracic paravertebral region on radiography and CT. Bone marrow imaging of the thorax by means of both Tc-99m nanocolloid and phytate demonstrated uptake of the tracer in the mediastinal mass, establishing the diagnosis of EMH.     

Clinical usefulness of In-111 chloride and Tc-99m Sn colloid scintigraphy in the diagnosis of intrathoracic extramedullary hematopoiesis

We report a case of intrathoracic extramedullary hematopoiesis associated with hemolytic anemia. While the paravertebral localization of the lesions demonstrated on CT and MRI was suspicious of intrathoracic extramedullary hematopoiesis, In-111 chloride and Tc-99m Sn colloid bone marrow scintigraphies showing a bone marrow element of the lesion were useful to confirm the diagnosis.     

Scintigraphy in a patient with complicated osteopetrosis

Skeletal, reticuloendothelial and renal images were obtained on a patient with osteopetrosis using Tc-99m MDP, Tc-99m HSA millimicrospheres and Tc-99m DTPA respectively. The bone scan showed increased uptake in multiple fracture sites, in the frontal bone, and in the splayed metaphyses of long bones while the remainder of the skeleton appeared normal. Reticuloendothelial images demonstrated an absence of bone marrow activity, hepatosplenomegaly and a site of extramedullary hematopoiesis. A renogram demonstrated a left kidney displaced and distorted by the massive splenomegaly.     

Tc-99m nanocolloid scintigraphic imaging of intracranial meningeal extramedullary hematopoiesis in a patient with idiopathic myelofibrosis

Meningeal extramedullary hematopoiesis (EMH) is a rare finding in idiopathic myelofibrosis. Intracranial EMH is typically asymptomatic and sites are usually found by chance. Diagnosis of EMH is difficult, based on clinical circumstances and the use of different diagnostic imaging modalities, such as CT, MRI or radionuclide imaging. We present a case with intracranial medullary hematopoiesis due to idiopathic myelofibrosis diagnosed with Tc-99m nanocolloid scintigraphy. Cranium SPECT images that were performed with Tc-99m nanocolloid showed increased radiotracer uptake in the bilateral parietal, bilateral frontal and left occipital bones and especially in falx cerebri of sinus sagittalis superior. In Tc-99m MDP bone scintigraphy, increased osteoblastic activity in the left frontal and parietal bones, in shoulders, knee and ankle joints, and in both metatarsal bones were seen. After gadodiamid injection, Tl weighted MRI showed diffuse contrast increased in the meningeal areas surrounding the brain. A biopsy of the mass revealed extramedullary hematopoiesis composed of erythroblasts, mature and immature myeloid cells, and megakaryocytes. It was deduced that these described foci of EMH.     

Gd-EOB-DTPA enhancement pattern of hepatocellular carcinomas in rats: Comparison with Tc-99m-IDA uptake

The enhancement pattern of chemically induced hepatocellular carcinomas (HCCs) after intravenous administration of the hepatobiliary magnetic resonance (MR) contrast agent gadolinium-EOB-DTPA (ethoxybenzyl-diethylenetriaminepentaacetic acid) was compared with the uptake pattern of technetium-99m-labeled iminodiacetic acid (IDA), a hepatobiliary radioactive tracer. The hepatocyte uptake of both the contrast agent and the scintigraphic agent has been shown to be driven by the organic anion transporter. The tumors enhanced less than the liver after Gd-EOB-DTPA administration, whereas the Tc-99m-IDA uptake of differentiated HCCs exceeded that of the liver at 30 minutes and 3 hours after administration. The enhancement pattern of a differentiated HCC with Gd-EOB-DTPA does not mirror that seen with Tc-99m-IDA.     

Granulocyte accumulation in ischemic/reperfused myocardium: Assessment with a technetium-99m-labeled antigranulocyte monoclonal antibody in the dog

This study tested the usefulness of technetium-99m-labeled antigranulocyte monoclonal antibody BW250/183 (AGMAb) for identifying granulocyte accumulation in ischemic/reperfused canine myocardium. In dogs with 90 minutes coronary artery occlusion and 180 minutes reperfusion (n = 8), ischemic/reperfused myocardial samples demonstrated 8.5 +/- 2.4 times more Tc-99m-AGMAb accumulation than nonischemic samples. Dogs given Tc-99m-labeled nonspecific human immunoglobulin instead of Tc-99m-AGMAb (n = 3) had about half as much accumulation (4.5 +/- 1.6, P < .05). Ex vivo myocardial imaging of Tc-99m-AGMAb demonstrated marked uptake in infarcted regions identified by absent triphenyl tetrazolium chloride staining. The amount of uptake was inversely related to the severity of ischemia (determined by radioactive microspheres) and directly correlated with tissue myeloperoxidase activity, a specific marker of granulocyte accumulation. No increase in Tc-99m-AGMAb uptake occurred in dogs with 90 minutes ischemia and no reperfusion (n = 3) or 15 minutes ischemia and 180 minutes reperfusion (n = 2). In conclusion, Tc-99m-AGMAb is taken up in reperfused infarcted myocardium by both nonspecific and specific mechanisms. Because the amount of uptake reflects myocardial granulocyte accumulation, Tc-99m-AGMAb combined with nuclear imaging techniques may be useful for studying inflammatory processes in the heart in experimental animal models and human beings.     

Imaging osteomyelitis with Tc-99m-labeled antigranulocyte antibody Fab' fragments

PURPOSE The purpose of this study was to evaluate the diagnostic value of Tc-99m-labeled antigranulocyte antibody fragments in the diagnosis of osteomyelitis. MATERIALS AND METHODS Thirty immunoscintigrams were evaluated retrospectively with 740 MBq (20 mCi) Tc-99m-labeled antigranulocyte antibodies. The final diagnoses were confirmed by histology, magnetic resonance imaging, computed tomography, and clinical follow-up. RESULTS In the retrospective analysis, 20 of 30 patients (67%) demonstrated a true-positive result. Three of 30 patients (10%) had a false-positive result. A false-negative result was found in a diabetic patient with a perforating ulcer of the foot. Six of 30 patients had a true-negative result. A high sensitivity of 95%, a relatively high specificity of 67%, and a high diagnostic accuracy of 86% were present in this study. CONCLUSION Tc-99m labeled monoclonal antibody-Fab' fragments are suitable for the detection of osteomyelitis. Its clinical application is simple. Its use guarantees a reliable and accurate diagnostic result just 1 to 2 hours after injection, making a late scan unnecessary. Coxarthrosis or hyperostosis can lead to false-positive results. A perforating ulcer of the foot may result in a false-negative conclusion.     

Lymphoscintigraphic sentinel node imaging and gamma probe detection in breast cancer with Tc-99m nanocolloidal albumin: results of an optimized protocol

PURPOSE: The purpose of this study was to aid in the standardization of lymphoscintigraphy for detecting the sentinel node (SN) in breast cancer using Tc-99m-labeled nanocolloidal albumin. MATERIALS AND METHODS: One hundred twenty-three women with proved breast cancer were enrolled. Four injections of 10 to 15 MBq (0.27 to 0.41 mCi) Tc-99m nanocolloid in 0.1 ml physiologic saline were administered intra- and subdermally at the margin of the skin overlying the tumor. Planar scintigraphic images in the lateral and anterior projections were obtained 2.5 to 18 hours after tracer administration. With a gamma probe used as a guide, all radioactive lymph nodes in the axilla were resected. Complete dissection then followed. RESULTS: In 116 of the 123 (94%) women, axillary nodal tracer uptake was revealed. Six of the 7 women in whom detection failure occurred had histologically proved tumor infiltration of the lymphatics and axillary involvement. In 36 (31%) of the patients with visualized lymph nodes, the SN was metastatic. The remaining 80 patients with negative SN included three cases with axillary involvement. The sensitivity of the SN with respect to the histologic status of the entire axilla thus was 92.3%, and the negative predictive value was 96.3%. The overall accuracy of the method was 97.4%. The number of hot nodes in women with and without axillary involvement was significantly different. CONCLUSIONS: The described protocol represents an easily reproduced and reliable method for SN detection in breast cancer. Furthermore, the number of visualized axillary nodes reflects the histologic status of the axilla.     

Noninvasive approaches to diagnose intrathoracic extramedullary hematopoiesis: 18F-FLT PET/CT and 99mTc-SC SPECT/CT scintigraphy

Extramedullary hematopoiesis refers to the presence of hematopoietic elements in locations other than the bone marrow medullary space. It occurs as a compensatory mechanism to impaired hematopoiesis resulting from a variety of pathological conditions. Because of the hazards of biopsy of a highly vascular hematopoietic mass, it is desirable to establish the diagnosis noninvasively. We report a case where 18F-fluoro-3'deoxy-L-thymidine PET/CT and 99mTc-SC scintigraphy were used as a noninvasive modality to diagnose extramedullary hematopoiesis.     

Extramedullary paraspinal hematopoiesis in thalassemia: CT and MRI evaluation.

We present a comparative CT and MRI study of the paraspinal extramedullary hematopoiesis in 32 thalassemic patients. The patients were classified into four groups according to the MRI and CT imaging findings. Active recent extramedullary paraspinal hematopoietic masses show soft tissue behavior in both CT and MRI. Older inactive masses reveal iron deposition or fatty replacement. Combined imaging findings of paraspinal extramedullary hematopoiesis revealed the phase of its evolution and the correct diagnosis.     

Diagnosis of orthopedic infection in clinical practice using Tc-99m sulesomab (antigranulocyte monoclonal antibody fragment Fab'2)

OBJECTIVE: The aim of the study was to analyze the use of Tc-99m-labeled antigranulocyte monoclonal antibody fragment Fab'2 (SMab, Leukoscan) in the diagnosis of acute osteomyelitis and articular prosthesis infection. One hundred seventeen patients (118 studies) have been included, 92 women and 25 men. Thirty-seven had a suspicion of osteomyelitis and 81 with suspicion of infection of a hip (35 patients) or a knee (45 patients) prosthesis. The mean age was 64 years. A 3-phase bone scan and a SMab scan were obtained in all patients. Antigranulocyte scans were obtained within 3 and 8 hours postinjection of 20 mCi (740 MBq) of Tc-99m-labeled antibody. Diagnosis of infection was based on bone biopsy in 8 cases and on at least 2 positive cultures in the remaining cases. Infection was ruled out with negative cultures or 1-year patient follow up with negative C-reactive protein and normal erythrocyte sedimentation rate. RESULTS: Sensitivity, specificity, accuracy, and negative predictive value of Tc 99m-SMab scintigraphy were: 75%, 95%, 87%, and 92% for long bone osteomyelitis and 80%, 89%, 87%, and 91% for articular prosthesis infection, respectively. Positive predictive values were 83% and 63%, respectively. CONCLUSION: Tc-99m-antigranulocyte monoclonal antibody fragment Fab'2 scintigraphy seems to be a useful method in the diagnosis of osteoarticular infection.     

The value of radionuclide studies in children with autosomal recessive polycystic kidney disease

PURPOSE: To describe and analyze the appearances of autosomal recessive polycystic kidney disease (ARPKD) on Tc-99m DMSA and Tc-99m HIDA scintigraphy. MATERIALS AND METHODS: The authors evaluated scintigraphic findings for 13 boys and 9 girls (age range, 2 months to 22.75 years; mean, 7.5 years) with ARPKD. Fourteen children underwent Tc-99m DMSA and 20 underwent Tc-99m HIDA scintigraphy according to European guidelines. Kidney outline, internal structure, tracer uptake, and differential function were analyzed on Tc-99m DMSA images, whereas relative liver lobe sizes, hepatocyte tracer uptake, time to peak, and excretion into the biliary tree and gut were evaluated on Tc-99m HIDA scans. RESULTS: On Tc-99m DMSA images, loss of kidney outline and internal structure was seen in 75% of the scans, and patchy tracer uptake with focal defects throughout the kidneys, particularly at the poles, was evident in 93%. In 85% of the cases, the Tc-99m DMSA changes did not correlate with the ultrasonographic findings where the kidneys are uniformly affected. Characteristic findings on Tc-99m HIDA scans were enlarged left liver lobe in 80%, a delay in maximal hepatocyte uptake in 68%, delayed tracer excretion into the biliary tree in 32% (with stasis in the prominent intrahepatic biliary ducts in 50% or pooling into the segmentally dilated biliary ducts in 25%), and delayed excretion into the gut in 40% of patients. CONCLUSIONS: In a child with clinically enlarged kidneys that appear diffusely hyperechoic on ultrasound, the appearances on Tc-99m DMSA imaging strongly support the diagnosis of ARPKD. The Tc-99m HIDA findings, especially of an enlarged left lobe of the liver with bile stasis or dilatation, further support the diagnosis.     

Use of technetium-99m as a radioactive label to study migratory patterns of leukocytes

Technetium-99m had been used as a radioactive label to study the migratory patterns of neutrophils. In a previous in vitro study, neutrophils were labeled with Tc-99m and infused into patients with and without various hematological disorders. Increased pulmonary localization was detected by scintillation camera within 10 min; this decreased gradually within 3 hr. Accumulation was seen in the liver and spleen at 3 hr. The same results were noted by using neutrophils labeled with Tc-99m sulfur colloid. In a patient with severe ulceration in the oral cavity, due to acute leukemia, Tc-99m-labeled transfused neutrophils that were collected by filtration leukopheresis were concentrated in the infected lesions.     

Database of normal human cerebral blood flow measured by SPECT: I. Comparison between I-123-IMP, Tc-99m-HMPAO, and Tc-99m-ECD as referred with O-15 labeled water PET and voxel-based morphometry

OBJECTIVES: Three accumulative tracers, iodine-123-labeled N-isopropyl-p-iodoamphetamine (I-123-IMP), technetium-99m-labeled hexamethylpropyleneamineoxime (Tc-99m-HMPAO), and technetium-99m-labeled ethyl cysteinate dimer (Tc-99m-ECD) are widely used to measure cerebral blood flow (CBF) in single-photon emission computed tomography (SPECT). In the present study, normal regional distribution of CBF measured with three different SPECT tracers was entered into a database and compared with regional distribution of CBF measured by positron emission tomography (PET) with H2(15)O. The regional distribution of tissue fractions of gray matter determined by voxel-based morphometry was also compared with SPECT and PET CBF distributions. METHODS: SPECT studies with I-123-IMP, Tc-99m-HMPAO, and Tc-99m-ECD were performed on 11, 20, and 17 healthy subjects, respectively. PET studies were performed on 11 healthy subjects. Magnetic resonance (MR) imaging studies for voxel-based morphometry were performed on 43 of the 48 subjects who underwent SPECT study. All SPECT, PET, and MR images were transformed into the standard brain format with the SPM2 system. The voxel values of each SPECT and PET image were globally normalized to 50 ml/100 ml/min. Gray matter, white matter, and cerebrospinal fluid images were segmented and extracted from all transformed MR images by applying voxel-based morphometry methods with the SPM2 system. RESULTS: Regional distribution of all three SPECT tracers differed from that of H2150 in the pons, midbrain, thalamus, putamen, parahippocampal gyrus, posterior cingulate gyrus, temporal cortex, and occipital cortex. No significant correlations were observed between the tissue fraction of gray matter and CBF with any tracer. CONCLUSION: Differences in regional distribution of SPECT tracers were considered to be caused mainly by differences in the mechanism of retention of tracers in the brain. Regional distribution of CBF was independent of regional distribution of gray matter fractions, and consequently the blood flow per gray matter volume differed for each brain region.     

An improved kit formulation of a dopamine transporter imaging agent: [Tc-99m]TRODAT-1.

Recently, [Tc-99m]TRODAT-1, the first Tc-99m-labeled tracer for imaging CNS dopamine transporters in humans, was reported. This tracer displayed excellent specific binding to dopamine transporters in the basal ganglia region of the brain, thus it is potentially useful for the diagnosis of deficit of dopamine transporters in neurodegenerative diseases, such as Parkinson's disease. Preparation of [Tc-99m]TRODAT-1 was previously achieved by a multistep kit formulation. It is highly desirable to further improve the preparation by developing a simplified one-vial formulation with a reduced amount of TRODAT-1 ligand for routine clinical use. To achieve this goal, a series of studies to optimize labeling efficiency by varying a combination of factors (amount of free ligand, reaction reagents, and reaction pH) was carried out. [Tc-99m]TRODAT-1 prepared by this new kit formulation was evaluated by assessing the brain uptake and target (striatum) versus nontarget (cerebellum) ratios in rats. Appropriate amounts of various ingredients for a one-vial kit formulation providing > or =90% radiolabeling yields were identified. The most consistent and reliable formulation contained 10 microg of TRODAT-1 (a reduction of free ligand from 200 microg to 10 microg), 32 microg of SnCl2, 10 mg of sodium glucoheptonate, and 840 microg of disodium EDTA in one vial as a lyophilized kit. It is feasible to reconstitute the vial with [Tc-99m]pertechnetate (0.5-2 mL, < or =1110 MBq, 30 mCi), resulting in a final solution with a pH value of 4.5-5.0. [Tc-99m]TRODAT-1, prepared by this new kit, was stable at room temperature for 6 h. Biodistribution studies of this agent in rats with the new formulation showed similar regional brain distribution as compared with those obtained with the previous preparation (high striatum-to-cerebellum ratio). In conclusion, using this lyophilized one-vial kit formulation, [Tc-99m]TRODAT-1 can be prepared with greater than 90% radiochemical purity. This simplified kit will significantly improve the reliability of preparation of this agent for routine clinical use.     

Extramedullary hematopoiesis. Demonstration by transmission and emission computed tomography

Extramedullary hematopoiesis occurring in the thorax is a well-known complication of a number of various blood dyscrasias, and its appearance with planar Tc-99m sulfur colloid marrow scintigraphy and transmission computed tomography (CT) has been described previously. The authors present a case of thoracic extramedullary hematopoiesis evaluated by CT and emission computed tomography (ECT).     

The use of external radioactive markers in scintimammography

In Tc-99m MIBI scintimammography, the exact localization of foci of increased tracer uptake or the exact anatomic correlation of palpated breast masses with a scintigraphic finding is difficult. The authors describe three patients with known or possible malignant breast lesions for whom the use of external radioactive markers successfully helped to provide this information, thus improving the diagnostic accuracy and guiding decision-making in the patients' treatment.     

Sclerosing cholangitis: cholescintigraphy with Tc-99m-labeled DISIDA

Four patients with primary sclerosing cholangitis (PSC) were examined with the hepatobiliary agent Tc-99m-labeled DISIDA (diisopropylphenylcarbamoyl iminodiacetic acid), and the results correlated with those of invasive cholangiography. Three of the four patients exhibited a typical pattern of multiple, persistent focal "hot spots" in the duct system, representing stasis within the segmental ductal dilatations (beading), also seen on cholangiography. Cholescintigraphy is superior to cholangiography in cases of suspected PSC where there is nonfilling of biliary radicals due to high-grade stenosis. The finding of delayed hepatic parenchymal clearance can allow estimation of the degree of obstruction of the various branches of the major bile ducts. Cholescintigraphy offers a noninvasive method of investigating patients with suspected sclerosing cholangitis, leading to earlier diagnosis. Confirmation with invasive cholangiographic procedures is recommended.     

A case of cavernous hemangioma of the small intestine diagnosed by scintigraphy with Tc-99m-labeled red blood cells

Hemangioma of the small intestine is rare, and the preoperative diagnosis of it is difficult. We report a patient with gastrointestinal bleeding for whom Tc-99m-labeled red blood cell scintigraphy was useful in diagnosing cavernous hemangioma of the small intestine. A 25-year-old man was referred to our hospital for recurrent iron deficiency anemia. Because of the patient's severe anemia, imaging was performed to locate the bleeding lesion in the gastrointestinal tract. Scintigraphy with Tc-99m-labeled red blood cells revealed pooling indicating a tumor and extravasation of blood from the tumor. Scintigraphy with Tc-99m pertechnetate revealed no abnormal accumulation. Partial resection of the small intestine was done, and cavernous hemangioma of the small intestine was diagnosed by using the specimen of resected tissue.