Calixto Pulmano

Intrathoracic and intra-abdominal Tl-201 abnormalities seen on rotating raw cine data on dual radionuclide myocardial perfusion and gated SPECT.

Purpose The lower thorax and upper abdomen are visualized during cardiac acquisition of rest Tl-201 and stress Tc-99m tetrofosmin gated SPECT. Thus, abnormal Tl-201 localization in these areas and in organs such as parts of the lungs, liver, spleen, and kidneys can be observed, including rotating raw cine data. Materials and Methods Other than cardiac images, the authors retrospectively reviewed Tl-201 rotating (raw data) images of 235 patients. Abnormal findings in the lungs, liver, spleen, and kidneys were identified that correlated with the patients’ clinical information; radiographic findings, including computed tomography and ultrasonography of the abdomen; other scintigraphic studies; and laboratory findings. Results In 53 patients, 54 abnormalities were detected. Intrathoracic abnormalities included focal areas of increased uptake, one in the right lower lung and another in the right upper lung that confirmed lung cancer, in 2 patients; diffuse uptake in both lungs in 11 patients; photopenia in the lung bases, which had resulted from pleural effusions, in 3 patients; and abnormal right liver configuration caused by elevation of the right hemidiaphragm in 1 patient. Of the intra-abdominal abnormalities, 12 patients with splenomegaly were identified. Six patients had focal areas of increased uptake in the gastric area. Nonvisualization of one kidney resulted from a congenitally absent right kidney in 1 patient, from right nephrectomy in 1 patient, from end-stage renal disease in another, and from a lower position of the left or right kidneys in 5 patients. Small and decreased uptake of both kidneys resulted from end-stage renal disease in 1 patient. Small and decreased uptake of one kidney was noted in 1 patient with renal scarring, in 1 patient with a renal stone, in 3 patients with chronic pyelonephritis, and in 5 patients with renal cyst(s). Conclusions Discernible intrathoracic and intra-abdominal abnormalities using rotating raw cine data from imaging in three-dimensional displays include diffuse or focal pulmonary uptake, pleural effusion, elevation of a hemidiaphragm, splenomegaly, increased uptake in the gastric area, renal abnormalities including absent or small kidneys, end-stage renal disease, renal scarring, renal cyst(s), and lower position of a kidney. The incidental finding of such abnormalities may prompt further clinical investigation.

Massive pulmonary embolism without symptoms demonstrated by radionuclide imaging with thromboemboli in both main pulmonary arteries

Massive pulmonary embolism is defined as an anatomic obstruction of 50% or more of the pulmonary artery. A reduction of at least 50% of the cross-sectional area of the pulmonary artery causes significant hemodynamic instability and marked hypoxia exhibiting syncope, apprehension, hypotension, diaphoresis, chest pain, altered mental status, and shortness of breath. A patient, who had no definite clinical signs and symptoms, was demonstrated to have massive pulmonary embolism by extensive mismatched ventilation-perfusion defects scintigraphically and confirmed as thromboemboli in the main pulmonary arteries on a standard CT of the thorax. The lack of clinical manifestations of massive pulmonary embolism might be related to the insidious onset and progressive formation of thromboembolism. The patient gradually adapted to and/or compensated for hemodynamic changes.

I-123 HIPDM planar brain images demonstrating crossed cerebellar diaschisis.

I-123 HIPDM or IMP brain planar images, as well as SPECT images, have been useful in the detection of large lesion(s) of the cerebral cortex. Planar imaging may be useful not only for cerebral lesions, but also for a cerebellar abnormality and in certain clinical situations, such as phobia to a gantry or being too heavy for the imaging table, when SPECT imaging cannot be performed. The authors concur that a large cerebral lesion can be detected by planar images; in addition, cerebellar lesions, such as the presence of crossed cerebellar diaschisis (CCD), may be detectable by planar imaging using I-123 HIPDM. This article presents a patient with a large cerebral infarct detected by planar imaging whose CCD has been demonstrated by planar images.

Bone metastasis demonstrated as a photopenic area in L3 on bone SPECT

A 72-year-old man with squamous cell carcinoma received 6,600 rads to the left upper lung after having refused surgical resection. The first bone scintigraph obtained 3 years after radiation therapy showed radiation changes in radioactive uptake in the thoracic spine. Seven years later the patient underwent a second bone scintigram because of low back pain, and the scan showed intense uptake in the edge of the L-3 vertebra on both sides and focal areas of abnormal uptake in the right acetabulum and right pelvis, and decreased uptake in the thoracic spine was less apparent compared with the first bone scan. Bone SPECT of the lumbar spine showed photopenia in the vertebral body of the L-3 vertebra with intense uptake in pedicles of both sides of the vertebral body. Concurrent MRls were consistent with metastasis. We concluded that metastatic tumor replacement of the vertebral body, the destruction of the vertebral body, or both resulted in the photopenic area in L-3 as seen on the SPECT. This is another example in which photopenia of a vertebral body should be suspected of being a malignancy.

Medullary thyroid carcinoma imaged by Tc-99m MIBI SPECT and Tl-201 chloride/Tc-99m pertechnetate subtraction SPECT.

A 61-year-old man with medullary thyroid carcinoma and local invasion of the left lobe of the thyroid had Tc-99m MIBI SPECT and Tl-201 chloride/Tc-99m pertechnetate subtraction SPECT after left lobectomy of the thyroid, using a triple-headed gamma camera. Tl-201 chloride/Tc-99m pertechnetate subtraction demonstrated a large mass with high Tl-201 uptake in the left neck. Although there was intense uptake in the tumor in the left thyroid bed on Tc-99m MIBI neck SPECT, there was also uptake in both salivary glands and the right lobe of the thyroid gland. Thus, uptake in the right lobe of the thyroid gland and the salivary glands might not be differentiated from tumor invasion or metastasis from medullary cell carcinoma. Compared with MIBI SPECT, Tl-201 chloride/Tc-99m pertechnetate subtraction SPECT shows more apparent delineation of tumor uptake and may be a preferable technique.

Extensive gastric varices demonstrated by technetium-99m red blood cell scintigraphy.

An alcohol abuse patient complicated by chronic pancreatitis had splenic vein thrombosis leading to gastric varices and underwent abdominal Tc-99m red blood cell scintigraphy. First pass study, sequential images up to 1 hour, and a 2.5 hour image showed abnormal radioactivity in the left side of the abdomen and midabdomen. In 24 hour images, the high level of activity in the left side persisted; in addition, there was accumulation of radioactivity in the cecum, ascending, transverse colon, the splenic fluxure, and descending colon. A splenectomy was performed and during the surgical procedure, a large dilated vein in the greater omentum was noted. It is reemphasized that delayed imaging up to 24 hours is important when the results of earlier images are equivocal or negative.

Abnormal scrotal finding on bone imaging. Increased radioactivity in a hemi-scrotum due to malignant lymphoma.

An incidental photopenic area in the scrotum may be found on bone scintigraphy; such a lesion can be due to a benign disease (hydrocele). In contrast, increased activity of the hemi-scrotum on bone scintigraphy may indicate a malignant lesion. A 68-year-old man with enlargement of the right scrotum was found to have increased radioactivity in the right scrotum occupying two thirds of the scrotum on an anterior bone scan. On ultrasound examination, this scrotal enlargement showed diffuse hypoechoic density in the right scrotum. The patient underwent right orchiectomy and resection of right spermatic cord; pathologic examination confirmed malignant lymphoma with hematopoietic origin. Bone scan interpretation should include observable asymmetrical soft tissue activity of the scrotum to depict scrotal abnormality

Artifact of cold lesions on skull SPECT of a patient with Paget's disease secondary to pixel overflow.

Various SPECT imaging artifacts have been described. One of them is pixel overflow caused by excessive radiotracer deposition in bone, resulting in areas of very low or absent activity on SPECT. Pagets disease of bone is characterized by intense and extensive radiotracer localization on bone imaging. A patient with Pagets disease is described whose planar bone scintigraphy and radiography showed osteoblastic and sclerotic areas of the skull, whereas SPECT showed photopenic and photon-deficient areas interposed with diffuse uptake in the skull. This indicates that bone SPECT might give artifacts of cold lesions secondary to pixel overflow as a result of excessive radiotracer deposition.

A prominent porta hepatitis resulting in a rim sign appearance on cholescintigraphy.

Invagination of fat into the porta hepatis, resulting in a rounded photon-deficient area surrounded by a rim of radioactivity in the left medial hepatic lobe, was shown on a cholescintigram. The hepatic bile duct adjacent to the prominent porta hepatis containing invaginated fat, as shown on CT of the liver, contributed to a rim of radioactivity. To avoid interpretation of a “rim” sign caused by either an inflammed gallbladder or an abscess, ultrasonographic correlation and possibly CT correlation should be considered, particularly in a case like this where the rim location is atypical.