Thallium-201 scintigraphy for ischaemic heart disease and infarct detection: comparison of rotating slant-hole tomography and planar imaging

A trial was undertaken to compare the diagnostic capabilities of rotating slant-hole tomography and raw scintigraphic planar images for the assessment of ischaemic heart disease and for infarct detection. Twenty patients with coronary artery disease established by arteriography and 29 patients who had suffered acute myocardial infarction as established by ECG and enzyme criteria were imaged, along with ten normal volunteers. Overall sensitivity and specificity figures, as well as Receiver Operating Characteristics (ROC) curves, were obtained. For infarct detection there was a sensitivity of 93% for tomography and 96% for planar imaging while the specificity was 80% for tomography and 95% for planar imaging. This loss of sensitivity and specificity was also apparent in the ROC curves and showed that there was no advantage from the use of rotating slant-hole tomography. For ischaemic heart disease the sensitivities for tomography and planar imaging were 83% and 91% respectively, while the specificities were 83% and 90% respectively. The ROC analysis again showed this reduction in the diagnostic capability of the test. It was concluded that rotating slant-hole tomography was no advantage in the assessment of ischaemic heart disease. Inter-and intra-observer variability was good with consistent responses in more than 90% of cases. No significant improvement was demonstrated in the poor ability of thallium scanning to specify the diseased vessels, and the phenomenon of false defects in the rotating slant-hole tomographic scans of some normal subjects was shown to affect the response of observers significantly.     

Value of magnetic resonance imaging in patients with a recent myocardial infarction: Comparison with planar thallium-201 scintigraphy

The diagnostic accuracy of spin-echo Magnetic Resonance (MR) imaging in the detection and localization of a recent myocardial infarction (mean 4 days old) was compared to planar thallium-201 scintigraphy in 20 patients with a documented myocardial infarction. A control group of 10 subjects underwent a similar MR imaging procedure without thallium-201 scintigraphy. T1-weighted MR images (TE 30 msec) showed abnormal thinning of the infarcted left ventricular wall during systole (<50% of the opposite wall) in 11 patients (55%). On T2-weighted multi-echo MR images, (TE 30–60–90–120 msec) abnormally increased signal intensity was found in 17 patients and coincided with the location of the infarction. Thallium-201 scintigraphy detected the infarction in 18 patients. Comparison of T2-MR imaging and thallium-201 scintigraphy showed concordant findings in 82% of the left ventricular segments. In 9% of segements, thallium uptake was reduced with normal T2-MR and in 9% we found a normal thallium uptake with abnormal T2-MR findings. In all subjects of the control group, T1-MR images were normal, and only one subject showed increased signal intensity on T2-MR images. We conclude that the diagnostic accuracy of MR imaging in detecting a myocardial infarction is similar to that of T1-201 scintigraphy.     

Lumbosacral transitional vertebral articulation: evaluation by planar and SPECT bone scintigraphy

It has been suggested that low back pain (LBP) may arise from lumbosacral transitional vertebral articulation (LSTVA) itself. It is known that bone scintigraphy is a valuable tool for the recognition of pain arising from bone and articular diseases. Therefore we aimed to show planar and SPECT bone scintigraphic findings of LSTVA and compare them with the LBP and X-ray findings. Twenty-eight patients (aged 20-63 years) in whom LSTVA had been identified radiographically were evaluated with planar bone scintigraphy, utilizing 99mTc methylene diphosphonate; and single photon emission computed tomography (SPECT) bone scintigraphy. Eighteen patients had LBP whereas 10 had not. There were 25 type IIA, one type IIB and two type IIIA LSTV articulation. On planar images, normal or non-focal minimally increased uptake superimposed on the upper sacroiliac joint was seen in patients without degenerative changes regardless of LBP whereas SPECT showed non-focal mild increased uptake on the area medial to the upper sacroiliac joint. Planar scans showed normal to non-focal mild, and mild-to-moderately increased uptake whereas SPECT demonstrated focal mild-to-moderately and markedly increased uptake in patients with degenerative changes without LBP and with LBP, respectively. The X-ray results showed an association of LBP degenerative changes, and the SPECT results showed a focal, markedly increased, uptake. We conclude that this focal, markedly increased, uptake may show the metabolically active degenerative changes of LSTV articulation and may help to reveal the pain arising from LSTVA. Therefore we propose that bone scintigraphy may be considered for the evaluation of patients with LBP thought to arise from LSTV articulation.     

Preoperative 99mTc-sestamibi scintigraphy in patients with primary hyperparathyroidism and concomitant nodular goiter: comparison of SPECT-CT, SPECT, and planar imaging

BACKGROUND: Investigations using a hybrid single photon emission computed tomography/computed tomography (SPECT-CT) scanning technique have been carried out in limited studies and have shown mixed results. However, the assessment of this technique for the detection of parathyroid adenoma in patients with a nodular goiter was performed in only one study with a small sample size. The aim of this prospective study was to assess the role of Tc-sestamibi parathyroid SPECT-CT scans for localization of parathyroid adenomas with a concomitant nodular goiter using Tc-methoxyisobutyl isonitrile (MIBI) scintigraphy and to compare it with SPECT and planar imaging. METHODS: This study was conducted on 48 patients with primary hyperparathyroidism and nodular goiter, who were candidates for parathyroid surgery and had been referred for parathyroid scintigraphy. The patients underwent an early set of planar Tc-MIBI scanning procedures first, followed by SPECT and CT scannings, and finally a delayed set of planar Tc-MIBI scannings. Sensitivity, specificity, negative and positive predictive values, and accuracy were determined on a per-parathyroid-gland basis for each scanning method, as defined by histology and follow-up. RESULTS: The surgery was successful in 48 out of 50 patients with primary hyperparathyroidism concomitant with thyroid nodularity, and data were completed for 80 sites in 48 patients. The accuracy of SPECT-CT in correctly identifying a parathyroid adenoma was 85.00, versus 75.00% for SPECT (P=0.01, significant). The sensitivity and specificity for SPECT-CT were 77.55 and 96.77%, respectively, versus 67.34 and 87.09%, respectively, for SPECT (P=0.12 and 0.12, not significant). There were nine sites that showed better localization on SPECT-CT scans relative to SPECT images, of which five sites were located in the ectopic regions. CONCLUSION: The results of our study indicate that SPECT-CT is more accurate than sestamibi planar imaging and SPECT for the preoperative identification of parathyroid lesions in patients with primary hyperparathyroidism concomitant with thyroid nodularity. Also, we would recommend the use of SPECT-CT for a workup of all patients with ectopic glands who are scheduled for minimally invasive parathyroid surgery.     

SPECT versus planar liver scintigraphy: is SPECT worth it?

Five hundred three planar and SPECT hepatic studies were reviewed separately by two experienced observers looking for focal disease. An equivocal reading meant referral to ultrasound or computed tomography (US/CT). The increase in correct readings and decrease in US/CT referrals per 100 positive and per 100 negative SPECT readings were calculated, then the increase in correct readings and decrease in US/CT referrals for various positive rates of liver involvement determined. At our institution, the overall positive rate is approximately 13% yielding 1.1 and 0.83 more correct readings and 1.8 and 2.0 fewer US/CT referrals per 100 cases for each reader, respectively; a marginal benefit for SPECT over planar scintigraphy.     

Abdominal hernias: imaging review and historical perspectives

Many eminent anatomists originally described abdominal hernias, some of which are still named after the original authors. In this article, the radiologic features of abdominal hernias are reviewed as imaged on x-ray, ultrasound, multidetector computed tomography, and magnetic resonance imaging. Recognition of the typical appearance of various types of abdominal hernias and associated adverse features such as bowel obstruction, perforation, strangulation, or volvulus formation can help in formulating an accurate diagnosis. A short biography of the scientists associated with eponymous hernias and their other important scientific contributions are also described.     

Quantitation in planar renal scintigraphy: which µ value should be used?

The attenuation coefficient value μ used by different authors for quantitation in planar renal scintigraphy varies greatly, from the theoretical value of 0.153 cm^–1 (appropriate for scatter-free data) down to 0.099 cm^–1 (empirical value assumed to compensate for both scatter and attenuation). For a 6-cm-deep kidney, such variations introduce up to 30% differences in absolute measurement of kidney activity. Using technetium-99m phantom studies, we determined the μ values that would yield accurate kidney activity quantitation for different energy windows corresponding to different amounts of scatter, and when using different image analysis approaches similar to those used in renal quantitation. With the 20% energy window, it was found that the μ value was strongly dependent on the size of the region of interest (ROI) and on whether background subtraction was performed: the μ value thus varied from 0.119 cm^–1 (loose ROI, no background subtraction) to 0.150 cm^–1 (kidney ROI and background subtraction). When using data from an energy window that could be considered scatter-free, the μ value became almost independent of the image analysis scheme. It is concluded that: (1) when performing background subtraction, which implicitly reduces the effect of scatter, the μ value to be used for accurate quantitation is close to the theoretical μ value; (2) if the acquired data were initially corrected for scatter, the appropriate μ value would then be the theoretical μ value, whatever the image analysis scheme. Received 15 July and in revised form 25 August 1999     

Rationalization of the optimal views in planar lung scintigraphy.

A knowledge of the segmental anatomy of the lungs is the cornerstone for interpreting lung scintigraphy. Many attempts have been made to determine the best views for the appreciation of segmental defects and various theories have been formulated to explain the mechanisms of this process. In earlier work, we hypothesized that the arrangements of the segments was the principal determinant of this process. However, data subsequently derived from work on a model of diffuse lung disease indicates that the external shape of the lobes and lungs may be the most significant contributor to the optimal views of the lungs.     

The diagnostic value of adding dynamic scintigraphy to standard delayed planar imaging for sentinel node identification in melanoma patients

Purpose  

The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients.     

Muscular sarcoidosis: Ga-67 scintigraphy and magnetic resonance imaging

Ga-67 scintigraphy is helpful in the assessment of active extrapulmonary sarcoidosis. Muscular involvement of sarcoidosis is often asymptomatic or nonspecific, and laboratory examinations do not provide convincing evidence of muscular involvement. The authors report a case of muscular sarcoidosis detected by Ga-67 scintigraphy. In a patient who had fever and arthralgia of both knee joints, Ga-67 scintigraphy showed mediastinal and hilar involvement of sarcoidosis with unexpected extensive muscular uptake. Magnetic resonance imaging revealed in detail intramuscular infiltration of sarcoid granuloma. Ga-67 scintigraphy is useful in detecting inflammatory muscular involvement of sarcoidosis and other multiorgan involvement.     

Invited. Ultrafast MR imaging of the abdomen: Echo planar imaging and diffusion-weighted imaging

Ultrafast MRI technique has become available with the introduction of new generation MR scanners for abdominal imaging. However, there is no consensus about the optimal imaging acquisition at the present time. Because single shot echo planar imaging (EPI) technique is based on high technology and had just applied in clinical imaging, further clinical investigation will be needed. Currently, the hypersensitivity to magnetic inhomogeneity and local magnetic susceptibility and the low spatial resolution may limit the widespread application of EPI technique. In addition to providing information for morphologic diagnosis, EPI will be more widely used for functional and qualitative diagnosis. Diffusion-weighted imaging can be used for differentiation of solid tumors according to their different cellular construction, evaluation of cystic lesions based on the different viscosity of their contents, and assessment of diffused pathologic changes in the parenchyma of solid organs. In addition to the previous parameters such as proton density and T1 and T2 values, diffusion factors may provide important information for the qualitative and dynamic evaluation of abdominal pathologic changes. Even though there are many difficulties that must be solved for diffusion-weighted imaging, a more wide application of this technique is expected through technologic improvement.     

Gastroesophageal scintigraphy in children: a comparison of posterior and anterior imaging

The purpose of this study was to compare the posterior dynamic imaging with the anterior imaging in the evaluation of children with gastroesophageal reflux (GER). Sixty-eight children (26 female, 42 male; age range 4 months to 7 years, median 21 months) were studied. After 4-hour fasting, all the subjects underwent gastroesophageal scintigraphy. Synchronous dynamic imaging in the anterior and posterior projections was performed with the subject in the supine position with a dual-head gamma camera equipped with low-energy general-purpose collimators at a rate of 30 s/frame for 40 min. The anterior and posterior images were visually evaluated for the presence of gastroesophageal reflux by two nuclear medicine physicians. The anterior and posterior images were correlated by Pearson correlation analysis, and inter-observer variability was evaluated by paired t-test and kappa value. There was a good correlation between the two projections with r-values of 0.906-0.990. The inter-observer agreement for interpretation of the anterior and posterior imaging was excellent (k: 0.83). In conclusion, anterior and posterior dynamic imaging showed excellent correlation in detection of GER in children. Posterior imaging is superior to anterior imaging in that it is more comfortable, and it reduces motion artifacts, especially for infants and anxious children; thus, it may be preferred over anterior imaging.