摘要:

PurposeThe use of I-123 in lieu of I-131 for diagnostic whole-body thyroid tumor scanning (DxRaI) in patients with differentiated thyroid cancer obviates the risk for stunning and affords significantly improved image quality. Because of the shorter half-life (13 hours) of I-123, images have been acquired primarily 6 or 24 hours after injection, potentially decreasing the sensitivity for detecting weakly avid thyroid tumor or remnant.Materials and MethodsThe authors evaluated the use of 111 to 185 MBq (3 to 5 mCi) I-123 for DxRaI under withdrawal conditions, imaging at 6, 24, and, in most cases, 48 hours. DxRaI with I-123 was compared in 13 evaluations performed in 10 patients, with post–I-131 treatment scans acquired early (2 to 3 days) and late (7 to 10 days) in all cases but one.ResultsOf 37 sites of tumor or remnant identified in post-treatment scans, 26 were found in the DxRaI I-123 scan (sensitivity, 70%). Of the 11 sites missed by I-123, 7 were seen only in the late post-treatment scans. Therefore, the sensitivity of I-123 imaging compared with the early post–I-131 treatment scans was 26 of 30, or 86.7%. In 10 cases, 48-hour I-123 imaging was attempted, yielding images of acceptable quality in eight of them. Lesion identification was improved on the 48-hour images; in one case, this allowed the identification of a site of tumor recurrence that was confirmed positive on the I-131 post-treatment scan.ConclusionsI-123 doses of 111 to 185 MBq for DxRaI provide acceptable levels of sensitivity overall and may permit 48-hour imaging for improved detection of weakly avid tumor or remnant without any risk for “stunning.”

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Although carcinoma is rarely metastatic to the thyroid gland, it has an established place in the differential diagnosis of cold nodules on radionuclide thyroid scans in patients with known cancers. A case of metastatic pleomorphic liposarcoma with involvement of the thyroid gland adds to the list of cases of metastases to the thyroid gland. A patient with known metastatic pleomorphic liposarcoma with a palpable thyroid nodule of 2 months’ duration had a thyroid scan with 130 MBq (3.5 mCi) Tc-99m pertechnetate. The scan showed a cold nodule occupying most of the right lobe of the thyroid. Cytologic analysis of a fine-needle aspirate from this cold nodule confirmed metastasis from the known primary cancer, pleomorphic liposarcoma. In a patient with a known primary tumor, a nodule in the thyroid gland should be considered a metastatic lesion, regardless of the time since the primary tumor was diagnosed and treated, until proved otherwise.

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

PurposeSmall-cell carcinoma is very aggressive, metastasizes early and often, and does not respond to most chemotherapy regimens. In approximately 50% of cases of prostate cancer, tumors are a combination of small-cell carcinoma and androgen-sensitive adenocarcinoma. It is widely believed that no successful treatment exists for androgen-independent prostate cancer.MethodsA 67-year-old man had undergone androgen ablation therapy and radical prostatectomy for prostate cancer followed by bilateral orchiectomy, limited radiation therapy, and unsuccessful chemotherapy for pain-causing metastatic bone disease. Biopsy and immunohistochemical analysis revealed neuroendocrine differentiation of the cancer. The full extent of metastatic disease was assessed successfully using In-111, a somatostatin derivative. Octreotide acetate was used to treat the tumors.ResultsIn-111 OctreoScan scintigraphy was more sensitive in the diagnostic demonstration of metastatic foci than was bone scanning. Therapy with the cold somatostatin derivative resulted in a rapid and significant relief of pain with significant tumor shrinkage. The patient remained in remission for at least 10 weeks, when he was lost to follow-up.ConclusionsSomatostatin analogs and their radionuclide and cytotoxic derivatives are recommended as adjuvant treatments for prostate carcinoma, especially in those patients who are at high risk for carcinoma recurrence after radical prostatectomy and who have advanced prostate carcinoma at the time of relapse. Because small-cell carcinomas of the prostate and lung are identical, these analogs may be useful in the detection and treatment of these tumors as well.

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

PurposeThis study evaluated the relation between the scintigraphic appearances of tibial stress fracture in military recruits and the likelihood that they would complete basic military training.Materials and MethodsThe authors retrospectively reviewed 58 Tc-99m MDP scans of recruits referred for possible tibial stress fracture and graded them according to the criteria of Zwas et al. (1987). Stress fracture appearances were correlated with clinical information such as the duration of rehabilitation and final outcome with regard to completion of the initial basic military training program.ResultsThirty-seven of the 58 patients (64%) had tibial stress fractures, all of which were located in the tibial diaphysis, with most occurring in the middle and lower thirds. Most (23 of 37) patients had stress fractures of grade I or II, and the others had grade III or IV stress fractures. There was no statistical difference in the proportion of patients with bilateral fractures between grades I–II and III–IV. There was no significant difference in the duration of rehabilitation for recruits successfully recovering from grade III–IV fractures compared with grade I–II fracture. There was a greater proportion of patients with lower grade fractures than higher grade fractures (P= 0.0006) who, despite rehabilitation, could not continue training because of unremitting or recurring pain at the fracture site and were medically discharged from military service.ConclusionsContrary to expectation, recruits with higher-grade stress fractures were not less likely to complete basic military training compared with recruits with lower grade stress fractures.

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has been used extensively to stage, restage, and follow neoplastic disease. However, focal accumulation of FDG may cause false-positive results in certain physiologic conditions. In this report, a unique PET and computed tomography (CT) combination scan helped define physiologic accumulation of FDG in the uterus during menstruation in a 40-year-old woman with a history of rectal melanoma and possible recurrent disease. An initial PET study, performed during menstruation, was followed immediately by a PET-CT scan, which showed marked accumulation of FDG in the posterior pelvis, localized to a retroverted uterus. An FDG PET-CT scan repeated 2 weeks later confirmed resolution of this “lesion.” Thus, combined PET-CT correctly differentiated physiologic FDG uptake in a retroverted uterus from recurrent rectal melanoma. This case shows that physiologic FDG accumulation in the uterus should be considered when focal FDG accumulation is observed in the pelvis in women of reproductive age.

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The goal of bleeding scintigraphy is to localize the site of origin of a hemorrhage to within general regions of the large or small bowel. Activity is typically seen to extravasate from the blood pool into the lumen, and the collection of activity then moves on sequential images, as a result of the cathartic action of blood. Sometimes, bleeding studies show a stationary focus of activity without subsequent movement. It is generally assumed that these foci represent fixed structures, such as the urinary tract or prominent vasculature, rather than acute extravasation of labeled blood into the bowel. The authors report three cases in which repeated studies showed that fixed foci of activity were, in fact, related to gastrointestinal bleeding. In two instances, the fixed foci represented extravasated blood that, for unexplained reasons, did not move during the study. In an additional case, the fixed activity visualized was ultimately shown to be prominent varices, which were implicated in the bleeding. Recognition of these possibilities, and consideration of possible strategies to localize the bleeding site further, should facilitate optimal patient treatment.

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Thymoma is the most common primary tumor of the anterior mediastinum, accounting for 20% to 30% of all mediastinal tumors. The recurrence rate after total resection of the thymoma ranges from 8% to 18%. The authors describe a patient with recurrent malignant thymoma imaged with Tc-99m MIBI, Tc-99m tetrofosmin, and Tc-99m (V) DMSA. Early and delayed Tc-99m MIBI and Tc-99m tetrofosmin scintigraphy showed increased uptake in the mediastinal area, as did Tc-99m (V) DMSA scintigraphy. Coronal SPECT images obtained with Tc-99m MIBI, Tc-99m tetrofosmin, and Tc-99m (V) DMSA showed increased uptake in the mediastinal lesion seen on a computed tomograph of the chest. However, the normal blood-pool activity of the heart and great vessels imaged with Tc-99m (V) DMSA obscured the recurrent malignant thymoma. Although Tc-99m (V) DMSA is a useful tumor-seeking agent, Tc-99m MIBI and Tc-99m tetrofosmin SPECT are preferred to Tc-99m (V) DMSA to detect primary and recurrent malignant thymoma.

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

In myocardial perfusion imaging, multiple-vessel involvement of coronary artery disease (CAD) sometimes makes diagnosis difficult. Transient left ventricular (LV) dilatation on Tl-201 myocardial SPECT is a useful finding that enables the clinician to identify patients with multiple-vessel disease. The aim of this study was to confirm the utility of measuring transient LV dilatation for the detection of multiple-vessel CAD in exercise Tc-99m tetrofosmin myocardial SPECT. The participants were 55 CAD patients and 20 controls who underwent Tc-99m tetrofosmin myocardial SPECT exercise and resting imaging. During exercise, 370 MBq (10 mCi) Tc-99m tetrofosmin was injected. Exercise images were obtained 30 minutes after injection. At 210 minutes after injection, 740 MBq (20 mCi) Tc-99m tetrofosmin was administered intravenously. The rest SPECT images were acquired 30 minutes later. Thirty-six radii at every 10 degrees were generated from the center of short-axis images. An area surrounded by 36 maximal points of the myocardial Tc-99m tetrofosmin counts on each radius was calculated for exercise and rest images. The area surrounded by the 36 maximal points in the same slice of the exercise and rest images was assigned the variables A (Ex) and A(R), respectively. The transient dilatation index (TDI) of the left ventricle was calculated using the formula mean A (Ex)/A(R) in the apical, middle, and basal myocardial short-axis images. In the controls, the TDI was 0.970 ± 0.021. In patients with CAD, the TDIs of one-vessel disease, two-vessel disease, and three-vessel disease were 1.034 ± 0.032, 1.093 ± 0.046, and 1.131 ± 0.076, respectively. The TDIs were significantly greater in patients who had more occluded coronary arteries (P< 0.01). If the mean + 2SD of the TDI (1.012) in controls were assumed to be the normal upper limit, the sensitivity, specificity, and accuracy of this method in detecting two-vessel or three-vessel disease would be 91.4%, 76.9%, and 84%, respectively. The TDI is a useful index for evaluating subendocardial ischemia noninvasively and detecting multiple-vessel disease clinically.

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

PurposeThe 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 MethodsOther 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.ResultsIn 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).ConclusionsDiscernible 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.

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:0363-9762    

出版商:OVID    

年代:2002

数据来源: OVID