Rectilinear scanning in the detection of acute myocardial infarction.

Myocardial scintigraphy with phosphate bone scanning agents is a new and very useful development in the detection of acute myocardial infarction. Initial experience using a rectilinear scanner is described in 50 consecutive patients admitted to hospital because of suspected myocardial infarction. The routine dose was 15 mCi/5 mg, 99Tcm stannous pyrophosphate intravenously with anterior, left anterior oblique, and lateral scans obtained 45-90 minutes after injection. There was only one false negative scan in 17 patients with proven acute myocardial infarction and that was 16 days after onset. There was no proven false positive investigation in seven patients in which fresh myocardial infarction could be definitely excluded, or in a further 11 cases in which it could be excluded with reasonable confidence. Myocardial scintigraphy was considered helpful in resolving the diagnostic problem in 27 out of 29 equivocal cases. It is concluded that myocardial scintigraphy with a rectilinear scanner is a highly accurate and safe procedure in the detection of acute myocardial infarction. The optimum scanning time is two to six days after onset of suspected infarction, when a diagnostic accuracy approaching 100 per cent can be expected.     

Detection of bone metastases in thyroid cancer patients: bone scintigraphy or 18F-FDG PET?

BACKGROUND: Similar to the situation in other tumour types, it is currently unclear whether fluorodeoxyglucose (FDG) positron emission tomography (PET) is adequate in the detection of bone metastases of thyroid cancer. The purpose of this retrospective study was to evaluate the performance of bone scans in comparison with FDG PET in the detection of bone metastases in patients with differentiated thyroid cancer (DTC). MATERIALS AND METHODS: Twenty-four patients had undergone both FDG PET and bone scans within 6 months because of suspected bone metastases. All scans were re-evaluated using all available additional imaging and clinical data for verification. Scan findings were scored as positive, negative or doubtful. RESULTS: Bone metastases were present in eight of 24 (33%) patients. Only bone scintigraphy but not FDG PET suggested the presence of bone metastases in three patients, all confirmed with magnetic resonance imaging (MRI)/X-ray. Five patients were identified with bone metastases on both bone scan and FDG PET, which was confirmed by computed tomography (CT)/MRI/X-ray in four. Five patients had doubtful findings on bone scans whereas FDG PET scans were negative. MRI showed degenerative disorders in two of five and was normal in two. Eleven patients had both a negative bone scan and FDG PET scan. CONCLUSION: In three of eight (38%) thyroid cancer patients bone metastases were only identified on bone scans. Therefore, bone scans are still valuable in detecting bone metastases in patients with DTC and can not be replaced by FDG PET.     

Emission tomography with 99mTc-pyrophosphate in the diagnosis of acute myocardial infarction

Electrocardiograms (ECG) and enzyme criteria are usually used to confirm the diagnosis of acute myocardial infarction in the case of chest pain. However, ECG is not always diagnostic. Elevated enzyme values may be due to causes other than myocardial infarction. In uncertain cases, the ECG and enzyme criteria can be supplemented by emission tomography, performed with technetium pyrophosphate that will accumulate in the site of infarction. Twenty-nine patients with suspected acute myocardial infarction were studied with emission tomography. Of these 12 had acute transmural infarction. Both enzyme tests and ECG were diagnostic in only 7 of these 12 cases, 4 had positive enzyme tests but a nondiagnostic ECG and in one case neither enzymes nor ECG were diagnostic. In 11 patients the infarcted myocardial area was detected with emission tomography. Six patients had acute nontransmural infarction. Only 2 of these had positive emission tomography. The chest pain was not due to infarction in 11 patients. All these patients had negative emission tomography. The sensitivity of emission tomography was 92% and specificity 100% in transmural acute infarction. In nontransmural infarction the specificity was only 33%. Emission tomography is a valuable diagnostic tool. It may be the decisive method when ECG and enzymes are not diagnostic. Emission tomography also shows the localization and size of the infarcted area in the myocardium.     

A critical review of the efficacy of 99mTc pyrophosphate in detecting myocardial infarction in 103 patients.

Patients imaged with 99mTc pyrophosphate for myocardial infarction between October 1975 and March 1976 were reviewed. There were 103 patients and 114 images obtained. The clinical criteria of either or electrocardiographic changes were used to validate a myocardial infarct. We experienced 92.4% true negatives, 68.7% true positives, 7.5% false positives and 31.3% false negatives. It technically compromised scans were exclude (those with blood-pool activity, overlying costal cartilage), the false-negative rate was 15.4%. These data show that the presence of a negative phosphate scan does not rule out the possibility of a recent small, less than 2.5-cm subendocardial myocardial infarction.     

Detection and size estimation of acute myocardial infarction using 99Tc-glucoheptonate.

Twenty-seven patients with suspected acute myocardial infarction were studied by precordial scanning after intravenous administration of 99mTc-gluchoheptonate 2-48 hr after the onset of chest pain. Fifteen of the patients had clinically documented acute myocardial infarctions. Twelve of these 15 (80%) had areas of distinctly increased tracer uptake in the region of the heart. The three infarctions not identified by scan had peak serum CPK values of less than 300. In seven patients without infarction, no distinct areas of increased tracer uptake were found in the region of the heart. Five patients could not be classified as to whether infarction had or had not occurred. Three had abnormal scans, the significance of which is uncertain. Infarct size was estimated from the area of increased 99mTc-glucoheptonate concentration on scan and compared to peak serum CPK values. A linear correlation with a correlation coefficient of 0.77 was found. Technetium-99-m-glucoheptonate scanning was useful for the identification and size estimation of moderate- to large-size transmural and nontransmural acute myocardial infaractions.     

111In-antimyosin Fab scintigraphy in cardiovascular diseases: (multicenter clinical trial)

In a multicenter study, a total of 380 patients with myocardial infarction, myocarditis and cardiomyopathy underwent 111In-Antimyosin Fab myocardial imaging. 111In-Antimyosin Fab was administered intravenously and myocardial images were obtained 48 hours later. Only 3 patients developed mild adverse effects. Human antimouse antibodies were detected in 7 patients. Positive scans in patients with myocardial infarction were seen in 92/119 (77%) within 2 weeks after the onset of myocardial infarction, in 58/71 (82%) at 3-4 weeks, in 20/22 (91%) at 4-8 weeks and 17/31 (55%) thereafter. The location of myocardial damage delineated by 111In-Antimyosin Fab imaging was concordant with the infarct location by ECG and coronary angiography. In patients with myocarditis, 111In-Antimyosin Fab uptake was positive in 7/12 (58%) within 8 weeks and 6/17 (35%) thereafter. Positive 111In-Antimyosin Fab scans were seen in 12/36 (33%) in dilated cardiomyopathy and in 17/19 (89%) in hypertrophic cardiomyopathy. Although the mechanism of persistently positive 111In-Antimyosin Fab images in the subacute to chronic stage of myocardial infarction and myocarditis remains to be clarified, 111In-Antimyosin Fab may be useful for the detection of the diseases and in evaluating the prognosis of patients with cardiomyopathy.     

Evaluation of 111In leukocyte whole body scanning.

Indium-111 oxine, polymorphonuclear cells isolated and labeled with 111In were used for studying absecesses and inflammatory conditions. There were 64 total scans done in 59 patients, 32 male and 27 female, aged 3-81 years (average, 51). The original clinical diagnosis was abscess in 33 patients. The whole blood cell scan was abnormal in 12 (36%) of these, and a good clinical correlation was obtained in 11 of the 12. In the 21 with a normal scan, 18 had no evidence of abscess, yielding one false-positive and three false-negative interpretations in the abscess group. Thirteen patients had fever of unknown origin, nine had negative scans and no subsequent evidence of abscess, and four had positive scans with good correlation in three. Acute bone and joint infections were positive on scan (4/4), whereas chronic osteomyelitis was negative (0/2). Three patients with acute myocardial infarction and three of four with subacute bacterial endocarditis had normal scans. All three studies in renal transplant rejection showed positive uptake in the pelvic kidneys. Indium-111 white blood cell scans have proved useful to diagnose or exclude a diagnosis of abscess or inflammatory condition infiltrated with polymorphonuclear leukocytes.     

Enhanced myocardial fluorodeoxyglucose uptake following Adriamycin-based therapy: Evidence of early chemotherapeutic cardiotoxicity?

AIM: To analyze changes in myocardial glucose metabolism using fluorodeoxyglucose (FDG)-positron emission tomography (PET) in patients treated with adriamycin and to investigate the clinical significance of these changes.METHODS: Considering that FDG-PET scanning has the ability to show changes in glucose metabolism in the myocardium, we retrospectively analyzed the FDGPET studies of 18 lymphoma patients treated with adriamycin-based chemotherapy in both the preand posttherapy setting. Cardiac contractile parameters such as left ventricular ejection fraction were not available for correlation in all patients due to the short duration and the level of cumulative dose administered in these patients during the time of the follow-up FDG-PET study. The change in myocardial glucose utilization was estimated by change in standard uptake values (SUV) in the myocardium.RESULTS: We observed a significant change in SUVmean values in the myocardium (defined as more than change in cardiac SUVmean between pre-and post-chemotherapy PET) in 1 patients, whereas 6 patients did not show any significant cardiac FDG uptake in both preand post-therapy PET scans. Patients were divided into three groups based on the changes observed in myocardial tracer uptake on the followup 18 F-FDG-PET study. Group A (n = 8): showed an increase in cardiac 18 F-FDG uptake in the post-therapy scan compared to the baseline scan carried out prior to starting adriamycin-based chemotherapy. Group B (n = 6): showed no significant cardiac 18 F-FDG uptake in post-therapy and baseline PET scans, and group C (n = 4): showed a fall in cardiac 18 F-FDG uptake in the posttherapy scan compared to the baseline scan. Mean cumulative adriamycin dose (in mg/m 2 ) received during the time of the follow-up FDG-PET study was 256. 25, 250 and 137.5, respectively.CONCLUSION: Our study shows three different trends in the change in myocardial glucose metabolism in patients undergoing adriamycin-based chemotherapy. A further prospective study with prolonged follow-up of ventricular function is warranted to explore the significance of enhanced FDG uptake as a marker of early identification of adriamycin-induced cardiotoxicity.     

Myocardial infarct imaging with 99mTc-pyrophosphate and 99mTc-methylene diphosphonate: lack of correlation.

A prospective study of eight patients with recent transmural myocardial infarction was performed using 99mTc-Sn-pyrophosphate and 99mTc-Sn-methylene diphosphonate in each patient. All pyrophosphate scans were strongly positive whereas the diphosphonate scan was strongly positive in only one case. We conclude that 99mTc-Sn-pyrophosphate is preferable to 99mTc-Sn-methylene diphosphonate for myocardial imaging.     

Experience with 111-In-chloride scanning in patients with focal defects on 99-mTc-sulfur colloid liver scans.

Thirty-nine patients with focal defects on the technetium liver scan were rescanned using 111-In chloride. Of 20 patients with hepatic malignancy, 11 had positive indium scans. None of the 19 with focal cirrhotic fibrosis had a positive indium scan although 5 of these had primary tumor. Thus, a positive indium scan suggests that the defect is malignant. A negative indium scan is less helpful, failling to distinguish between neoplasm and focal cirrhosis. Positive uptake in an extrahepatic primary neoplasm and negative uptake in the liver suggest that the hepatic lesion is not neoplastic.     

Positron emission tomography in breast cancer: a clinicopathological correlation of results

We conducted a retrospective study to evaluate the sensitivity, specificity and accuracy of positron emission tomography (PET) scans in 109 patients with primary recurrent or metastatic breast cancer. All patients had a PET scan, X-ray or CT scan of the chest, an ultrasound or CT scan of the liver and a bone scan. Mammography was available for 86 patients. Correlation between the PET scan result and histological findings were made. The sensitivity, specificity and accuracy of the PET scan were calculated for both the primary tumour (T) and lymph nodes (N). In patients with metastasis (M) the accuracy of the PET scan was compared with other imaging modalities. Histological results of the site in question were available in only 105 patients. Information for the primary tumour was available for 93 patients and for nodes in 74. The PET scan was accurate in 89.2% for (T), with 3.2% false positive and 7.6% false negative. For (N) the PET scan was accurate in 90.5% with 9.5% false negative. In the 86 patients who underwent both mammography and PET scanning, the PET scan was more accurate in 89.5% versus 72% (p = 0.0003). In the 19 patients with metastasis, the PET scan was in agreement with other imaging modalities in 100% of cases. PET scanning is the only non-invasive imaging procedure that will detect tumours in the breast, lymph nodes, lung, liver, bone and bone marrow with high sensitivity, specificity and accuracy. It is a valuable tool in the management of patients in all stages of breast cancer for diagnosis, staging and following treatment response.     

Role of technetium-99m planar bone scanning in the evaluation of low back pain

The records of 1018 patients with low back pain in a tertiary spine referral practice were reviewed. One hundred thirty-nine out of 1018 (13.6%) underwent technetium-99m planar bone scanning as part of their investigation. Seventy-three out of 139 scans (52%) showed increased uptake in some area, but only 27 out of 139 (19.4%) showed increased uptake specifically in the low back. Scans consistently yielded no findings with reference to the back when the prescan diagnosis was spinal stenosis, lumbar pain syndrome, herniated nucleus pulposus, or postlaminectomy syndrome. Some scans gave positive findings in patients with a diagnosis of degenerative disc disease, pseudarthrosis, spondylolisthesis, fracture, infection, metabolic disorder, or tumor. Positive scans were generally obtained early after presentation (within 3 months) and negative scans obtained later (after 6 months), suggesting that clinical suspicion is still the main indication for early scanning. Planar bone scanning was helpful in both diagnosis and therapeutic decisionmaking in many conditions.     

Staging of patients with carcinoma of the breast by bone scans? [author's transl)

Bone scans were performed in 170 patients with widespread breast cancer and metastases which were confirmed by the clinical course. In 82% a positive x-ray and in 95% a positive bone scan could be demonstrated. In 43 patients without bone metastases the ratio of false positive scans was 5%. Seventeen out of 50 patients with early cancer had abnormal scans. In 12 cases there were metastases proven by follow-up of at least 18 months. Assuming an incidence of 25% for bone metastases in patients with early breast cancer, bone scans with a sensitivity and specificity of 95% will be valid in staging. To validate this high incidence we investigated a second group of 97 patients with early cancer in a prospective study: in only 3 cases there was an abnormal scan. Using this low incidence bone scanning is calculated to be not valid for staging of breast cancer.     

CT scanning and surgical treatment of 1551 head injured patients admitted to a regional neurosurgical unit

Computed tomographic (CT) scans of 1551 recently head injured patients transferred to a regional neurosurgical unit (NSU) were reviewed. Some 90% of first scans were done outside normal working hours. More than a third of first scans were normal including a fifth of the patients who were in deep coma. Haematoma was found in 50%, contusion 28%, shearing injuries 13% and general swelling in 9%. In 22% the first scan led to urgent surgical evacuation of an intracranial haematoma. More than one scan was done in 41% of patients and more than two in 10%, making 2608 scans in all. Repeat scans were more often done when the first scan was abnormal. In only five of 554 patients (1%) whose first scan had been normal were contusions or haematomas seen on subsequent scans, and in none of these was surgery required. Of 997 patients whose first scan had been abnormal a new lesion (contusion, haematoma and/or infarction) was seen on a subsequent scan in 103 cases (10%). Surgery was required (for the first time), in 57 patients whose abnormal first scans had not indicated the necessity for surgery at that time. The implications of these and other findings for the scanning of recently head injured patients in general hospitals, as scanners become more widely available, are discussed in our accompanying paper on p. 88.     

Light scan evaluation of nonpalpable breast lesions

Transillumination light scanning of the breast was performed immediately before needle localization of 112 nonpalpable mammographic abnormalities detected in 103 patients. Twenty-four cancers were diagnosed in 23 patients. The positive predictive value for mammography was 21%. Ten (42%) of these nonpalpable cancers were not visible on transillumination light scanning. Eleven of 16 invasive ductal cancers and three of seven intraductal cancers were evident on transillumination light scans, but a single case of lobular carcinoma in situ was not evident. There were 12 false-positive light scan examinations. Transillumination light scanning had a 58% sensitivity, an 86% specificity, a 54% positive predictive value, and an 88% negative predictive value for small breast lesions. Therefore, the authors are unable to recommend delaying biopsy in patients with mammographic abnormalities on the basis of a negative light scan study.     

Prognostic impact of pre-transplantation computed tomography and 67gallium scanning in chemosensitive diffuse large B cell lymphoma patients undergoing hematopoietic stem-cell transplantation

OBJECTIVE: In the present study, we evaluated computed tomography (CT) and (67)gallium scanning ((67)Ga scan) pre-transplant as prognostic factors for overall survival (OS) and event-free survival (EFS) in patients with diffuse large B cell lymphoma, undergoing high-dose chemotherapy and stem-cell transplantation. PATIENTS AND METHODS: Forty-two patients were included. Of these, 9 (21%) had both positive CT and (67)Ga scans, 17 (41%) negative results with both techniques, and 16 (38%) positive CT/negative (67)Ga scan. Whole-body planar imaging and single-photon emission computed tomography (SPECT) were performed 72 h after an intravenous administration of (67)Ga citrate measuring between 7 mCi and 10 mCi (259-370 MBq). RESULTS: Patients with positive CT/positive (67)Ga scan had a significantly worse EFS and OS at 5 years than those with negative (67)Ga scan regardless of whether it was associated with a positive or a negative CT scan (29% and 16% vs. 81% and 93% vs. 88% and 100%, respectively, P < 0.001). After a median follow-up of 43 months (range 4-130 months), no differences were observed between patients with negative CT/negative (67)Ga scan and those with positive CT/negative (67)Ga scan, with an EFS and OS at 5 years of 88% versus 81% and 100% versus 93%, respectively. In multivariate analysis, the presence of a pre-transplant positive CT/(67)Ga scans adversely influenced both EFS and OS [HR 8, 95% confidence interval (CI) (1.4-38), P = 0.03 and HR 2; 95% CI (1.3-8), P = 0.02, respectively]. CONCLUSIONS: (67)Ga scan helps to identify, in the pre-transplant evaluation, two groups with a different outcome: one group of patients with positive CT and negative (67)Ga scans pre-transplant, who showed a favorable outcome with a low rate of relapse, and the other group of patients with both positive CT and (67)Ga scans pre-transplant, who showed a poor prognosis and did not benefit from autologous stem-cell transplantation. They should have been offered other therapeutic strategies.     

PET Scanning with (18)F 2-Fluoro-2-Deoxy-D-Glucose (FDG) in Patients with Melanoma. Benefits and Limitations

We reviewed our experience with positron imaging tomography (PET) scanning from 1996-1998 in 45 patients (51 scans) with high risk (n = 15) or recurrent melanoma (n = 30). Positive or negative PET findings were considered correct if confirmed or refuted by other radiologic modalities or biopsy within 6 weeks, or clinical follow up within 6 months. PET scans were usually obtained to make a decision regarding surgical management (29/51 scans, 57%) or to confirm that a patient was disease free (12/51 scans, 23%). PET results facilitated clinical decision making in 15/45 (33%) patients, often due to the detection of distant disease making a surgical procedure inappropriate (5/15, 33%). There were 3 false positive (6%) and 7 false negative (14%) PET scans. False negative scans occurred in patients with small volume disease of the lung (4 patients) or CNS (2 patients, 3 scans). Three patients had false positive scans. These were secondary to benign hepatic tumors and sarcoidosis (one patient each). One patient with stage IV melanoma had PET findings not confirmed by CT scanning or clinical follow-up. PET scanning was clinically useful in a third of patients in our initial experience, and false positives were uncommon. Small volume disease in the lung or CNS may be missed by PET, and additional imaging modalities should be obtained when patient management would be impacted.     

The significance of calcific valvular heart disease in Tc-99m pyrophosphate myocardial infarction scanning: radiographic, scintigraphic, and pathological correlation.

Technetium-99m pyrophosphate (PPi) is currently considered the best scanning agent for the diagnosis of acute myocardial infarction. False-positive scans have been reported in association with unstable angina, alcoholic cardiomyopathy, and ventricular aneurysms. In this study, 86% of patients (12/14) with either calcific aortic or mitral valvular heart disease had positive PPi cardiac scintiscans and the location of the PPi uptake was limited to the calcific valve in all (9/9) of the patients who underwent valve replacement surgery. Six patients with valvular disease without radiologic evidence of calcium had negative PPi heart images. Three of these patients had surgical valve replacement, and in none was there increased uptake in the resected valve. Seventy-five percent of the patients with calcified aortic valves had localization of the PPi activity to the area of the aortic valve, whereas 50% of the patients with calcified mitral valves showed a diffuse pattern of uptake on the cardiac image. In vitro demonstration of increased radioactivity in surgically removed cardiac valves warrants the conclusion that Tc-99m PPi is taken up by calcified heart valves. We conclude that while PPi heart scanning is a sensitive indicator of acute myocardial infarction, false-positive scans can occur in the presence of calcific valvular disease, due to localization of PPi in the calcified portion of the valve.     

CT imaging features and frequency of left ventricular myocardial fat in patients with CT findings of chronic left ventricular myocardial infarction

AIM: To determine the frequency of left ventricular myocardial fat in patients with computed tomography (CT) findings of chronic left ventricular myocardial infarction, and to review the typical CT imaging features. MATERIALS AND METHODS: A retrospective search of the CT and nuclear scintigraphy reports from 1998-2005 for chronic left ventricular myocardial infarction was performed. The study group comprised those cases with available CT examinations revealing findings of chronic left ventricular myocardial infarction. Assessment for the presence of various imaging characteristics of left ventricular myocardial fat was performed in all cases. RESULTS: The frequency of left ventricular myocardial fat in 47 patients with CT evidence of chronic left ventricular myocardial infarction was 51%. Typical CT imaging features include thin linear or curvilinear fat attenuation within left ventricular myocardium, most commonly subendocardial, often associated with left ventricular wall thinning and/or calcification, predominantly in elderly men. CONCLUSIONS: Fat in the left ventricular myocardium is a common additional finding in patients with CT findings of chronic left ventricular myocardial infarction. The potential, but as yet unproven, use of this CT imaging finding is that the radiologist may be able to suggest a potential diagnosis of chronic left ventricular myocardial infarction on unenhanced, thick-section, non-gated or non-triggered chest CT imaging where identification of myocardial wall thinning may be difficult.     

Detection of acute myocardial infarction by 99mTc-labeled D-glucaric acid imaging in patients with acute chest pain.

Definitive diagnosis of acute myocardial infarction early in the process is often difficult. An imaging agent that localized quickly and specifically in areas of acute necrosis could provide this critical diagnostic information. To determine whether imaging with 99mTc-labeled D-glucaric acid (GLA) could provide this information, we imaged a group of patients presenting with symptoms suggestive of acute infarction. METHODS: Twenty-eight patients presenting to the emergency department with symptoms highly suggestive of acute infarction were injected with 99mTC-GLA and imaged about 3 h later. RESULTS: The sensitivity of lesion detection was remarkably time dependent. Fourteen patients with acute infarction injected within 9 h of onset of chest pain had positive scans, even in the presence of persistent occlusion. The remaining 14 patients had negative scans. Nine patients with negative scans had acute infarction but were injected more than 9 h after onset of chest pain. The final diagnosis in the remaining 5 patients was unstable angina (3 injected <9 h and 2 injected >9 h after onset of chest pain). Six patients were reinjected with 99mTc-GLA 4-6 wk after their initial study to determine whether persistent positive scans occurred with this agent. All 6 had negative scans. CONCLUSION: This study suggests that 99mTc-GLA localizes in zones of acute myocardial necrosis when injected within 9 h of onset of infarction.