Interpretation Of Scintigraphy Research Articles

Dynamic blood flow imaging with 99mTc-hydroxymethylene diphosphonate as a therapeutic response marker in patients with Raynaud's phenomenon.

We evaluated the predictive value of dynamic blood flow scintigraphy with 99mTc-HDP (hydroxymethylene diphosphonate) for therapeutic response in patients with Raynaud's phenomenon (RP). Eighty patients who underwent dynamic blood flow scintigraphy using the one-hand chilling method were enrolled. We analyzed the quantitative variables as the ratio of chilled fingers to ambient fingers (CAfinger), that of the chilled hand to ambient hand (CAhand), and that of chilled fingers to ambient palm (FPR) (CAFPR) at 15 and 30s after 99mTc-HDP bolus injection. Total cumulative radioactivity counts for 180s were obtained. We evaluated the clinical utility of these quantitative parameters with other clinical variables, including RP severity, therapeutic compliance, types of RP, and scintigraphic interpretation of findings in patients with RP. Fifty-two patients showed poor therapeutic response. There were significant differences between good- and poor-therapeutic responder groups in RP intensity (p = 0.003), CAfinger15s (p = 0.008), CAfinger30s (p = 0.002), CAfinger180s (p = 0.011), CAhand15s (p = 0.008), CAhand30s (p = 0.007), CAhand180s (p = 0.017), CAFPR30s (p = 0.004), and CAFPR180s (p = 0.002). After multivariate logistic regression analysis, only CAfinger30s (p = 0.002) had an independent predictive value of the therapeutic response. 99mTc-HDP dynamic blood flow scintigraphy could be helpful in predicting the therapeutic response in patients with RP.

An end-to-end multi-task system of automatic lesion detection and anatomical localization in whole-body bone scintigraphy by deep learning.

Limited by spatial resolution and visual contrast, bone scintigraphy interpretation is susceptible to subjective factors, which considerably affects the accuracy and repeatability of lesion detection and anatomical localization. In this work, we design and implement an end-to-end multi-task deep learning model to perform automatic lesion detection and anatomical localization in whole-body bone scintigraphy. A total of 617 whole-body bone scintigraphy cases including anterior and posterior views were retrospectively analyzed. The proposed semi-supervised model consists of two task flows. The first one, the lesion segmentation flow, received image patches and was trained in a supervised way. The other one, skeleton segmentation flow, was trained on as few as five labeled images in conjunction with the multi-atlas approach, in a semi-supervised way. The two flows joint in their encoder layers so each flow can capture more generalized distribution of the sample space and extract more abstract deep features. The experimental results show that the architecture achieved the highest precision in the finest bone segmentation task in both anterior and posterior images of whole-body scintigraphy. Such an end-to-end approach with very few manual annotation requirement would be suitable for algorithm deployment. Moreover, the proposed approach reliably balances unsupervised labels construction and supervised learning, providing useful insight for weakly labeled image analysis. Supplementary data are available at Bioinformatics online.

The validity of salivary gland scintigraphy in Sjögren's syndrome diagnosis: comparison of visual and excretion fraction analyses.

The diagnostic validity of salivary gland scintigraphy in Sjögren's syndrome (SS) has not been conclusively defined. Whether a quantitative (excretion fraction) interpretation of scintigraphy is superior to a qualitative one (visual analysis) remains a matter of debate. We sought to determine whether the diagnostic discrimination of excretion fraction is higher compared to that obtained by visual analysis. Diagnostic test validity study that encompassed 137 suspected SS subjects who underwent scintigraphy for diagnostic purposes. Patients were diagnosed as SS and non-SS according to the rheumatologist's clinical judgment, and by using the American-European Consensus Group (AECG) and American College of Rheumatology (ACR) classification criteria. Visual analysis (normal vs. abnormal and Schall's classification grade) and excretion fraction scores were calculated. The diagnostic discrimination of these methods was compared through the area under the curve (AUC) analysis. Scintigraphy associations with SS clinical and laboratory features were assessed through multivariable regression analysis. Schall's classification AUC reached statistical significance in its diagnostic discrimination for SS clinical judgment (0.704 [95%CI 0.597-0.811]) and AECG criteria (0.764 [95%CI 0.641-0.886]). Similarly, submandibular excretion fraction was associated with SS diagnosis based on ACR (0.737 [95%CI 0.546-0.931]) and AECG criteria (0.715 [95%CI 0.597-0.833]). However, AUC comparisons between qualitative and quantitative methods did not yield statistically significant values. Both interpretation modalities were associated with SS serological features. Moreover, excretion fraction was also associated with salivary gland biopsy. SS diagnostic discrimination of excretion fraction is not superior to that obtained by qualitative visual analysis. Both qualitative and quantitative scintigraphy methods are associated with SS clinical and laboratory characteristics.

Voiding cystourethrography and 99MTC-MAG3 renal scintigraphy in pediatric vesicoureteral reflux: what is the role of indirect cystography?

Primary vesicoureteral reflux (VUR) is the most common urological anomaly in children. Voiding cystourethrography (VCUG) is considered the reference standard for the diagnosis of VUR. Even if it is a secure and standardized technique, it is still an invasive method, hence, the effort to find an alternative method to diagnose VUR. The aim of the study is to evaluate the diagnostic accuracy of 99mTC-MAG3 scintigraphy with indirect cystography in detecting VUR and to estimate any interobserver variability in 99mTC-MAG3 scintigraphy interpretation. The authors retrospectively reviewed all the pediatric patients who underwent both a VCUG and a 99mTC-MAG3 renal scintigraphy at the study institution between 2012 and 2016. A total of 86 children (and 168 renal units) were included. MAG3 scan revealed a sensitivity of 54% and a specificity of 90% with positive predictive value of 79% and negative predictive value of 73%. Each MAG3 scintigraphy was then independently and blindly evaluated by a pediatric urologist and two nuclear physicians. After revision, the concordance between VCUG and MAG3 in reflux cases dropped from 54% to 27% (on average), and the reviewers reclassified most examinations as non-conclusive. 99mTC-MAG3 renal scintigraphy with indirect cystography showed low sensitivity in detecting VUR of any grade and cannot, therefore, be proposed as completely alternative to VCUG in the diagnosis of VUR. Moreover, MAG3 scintigraphy interpretation for the diagnosis of VUR has a very high interobserver variability, mostly because of the lack of a correct and complete voiding phase.

Imagerie fonctionnelle et métabolique du neuroblastome en 2016

Neuroblastoma is the most common extracranial neoplasm in children. This disease has a great heterogenity in his presentation and prognosis. 123I-MIBG remains currently a key and reference exam for diagnosis, initial staging, prognosis and follow-up of neuroblastoma. SPECT/CT increased the diagnostic certainty of 123I-MIBG scintigraphy interpretation and help to reduce false negative and false positive results. Bone scan is yet not indicated. 18FDG-PET/CT is not superior to 123I-MIBG in stages 3 and 4. 18FDG-PET/CT is recommended in case of non-avid 123I-MIBG neuroblastoma. 18F-FDOPA PET/CT could represent an alternative exam to 123I-MIBG scintigraphy because of better spatial resolution and no interference with therapy. Other PET radiopharmaceuticals as 124I-MIBG or 18F-MFBG could be interesting and particularly 68Ga-peptides PET/CT as a theranostic agent in providing valuable information for pretherapeutic staging of neuroblastoma.

Diagnostic Imaging in Acute Pulmonary Embolism

The common strategy of combining clinical information, lung scintigraphy and pulmonary angiography in the diagnosis of acute pulmonary embolism (PE), has many limitations in clinical use. The major causes are that pulmonary angiography and lung scintigraphy are not universally available, and that pulmonary angiography is very expensive. The purpose of this thesis was to analyse different aspects of validity in regard to lung scintigraphy, pulmonary angiography, spiral CT, and ultrasound of the legs, with the subsequent intention of discussing new diagnostic strategies. Observer variations in lung scintigraphy interpretation when applying the PIOPED criteria were tested in 2 studies with 2 and 3 observers respectively and expressed as kappa values. The ability to improve agreement in lung scintigraphy interpretation was tested by training 2 observers from different hospitals. The impact of 3 observers' variations in lung scintigraphy interpretation when compared to pulmonary angiography, was tested by comparing the ROC areas of the observers. The value of combining subjectively derived numerical probabilities and the PIOPED categorical probabilities in lung scintigraphy reporting was compared to using the PIOPED categorization only, and this was tested by comparing ROC areas. The sensitivity and specificity of detecting an embolic source in the deep veins of the legs by ultrasound as a sign of PE when lung scintigraphy is inconclusive, was tested by comparison with pulmonary angiography. The sensitivity and specificity of spiral CT, compared to pulmonary angiography, was tested by comparison to pulmonary angiography. The inter- and intra-observer kappa values were in the range of moderate and fair. It was not possible to achieve better kappa values after training. Although observer variations were substantial, the accuracy did not differ significantly between the 3 observers. Incoorporating subjectively derived probabilities into lung scan reporting could not reduce the number of inconclusive investigations. Sensitivity and specificity of ultrasound in detecting PE was 0.70 and 0.97, respectively. However, 2 patients (of 9) had deep venous thrombosis and no pulmonary emboli at angiography. The sensitivity and specificity of spiral CT was 0.90 and 0.96, respectively. The observer variations at lung scintigraphy are substantial and may be difficult to improve between hospitals, even though the accuracy of observers in general is good. Although subjectively derived interpretation criteria did not show to be useful when added to categorical interpretation criteria, they may be useful when substituting established criteria. Despite recent progress in refining interpretation criteria, a substantial fraction of the patients still need pulmonary angiography to be performed. However, in many patients pulmonary angiography is not performed as prescribed. Spiral CT and ultrasound of the legs is a new favourable diagnostic strategy with a high validity in detecting venous thromboembolic disease, and a good availability and cost-effectiveness.

Gastroesophageal reflux scintigraphy: interpretation methods and inter-reader agreement

Scintigraphic imaging is a useful screening tool for patients with suspected gastroesophageal reflux. New scintigraphic interpretation methods have recently been introduced. This study was undertaken to evaluate the efficiency of various scintigraphic interpretation methods in the detection of gastroesophageal reflux and to measure their influence on inter-reader agreement. Scintigraphic images of 49 children with suspected gastroesophageal reflux were interpreted by three different methods: visual interpretation, time activity curves, and condensed images. The readings were performed by three specialists and a resident. The discordant results were resolved by a consensus reading done together by all interpreters based on the three different methods. The gastroesophageal refluxes were grouped according to their number, location and intensity. Gastroesophageal reflux scintigraphy revealed 22 patients with negative results and 27 with positive results. The sensitivity, positive predictive value and specificity for each of the three specialists vs. the resident were 96%, 96% and 81% vs. 96%; 93%, 90% and 96% vs. 81%; and 90%, 86%, and 95% vs. 73%, respectively. The mean inter-observer reproducibility (κ value) was 0.910 for visual interpretation, 0.652 for time activity curves and 0.789 for condensed images. Twenty-seven percent of the results were discordant and most of these refluxes were of low grade (92%), low intensity (77%) and localization in the distal esophagus (54%). Gastroesophageal scintigraphy is a useful tool for detecting patients with suspected reflux, and visual interpretation is better than the other two methods in terms of accuracy and inter-observer reproducibility.

Evaluation of a Solid Bolus Suitable for Esophageal Scintigraphy

This study was designed to select a suitable solid bolus for esophageal scintigraphy. Optimally, a bolus should leave minimal residual buccal and pharyngeal activity after being swallowed. We compared the oropharyngeal behavior of three boluses, i.e., omelette, egg white, and paté of 1- and 3-ml volume. Thirty patients without dysfunction of the upper esophageal sphincter were recruited for the study. Scintigraphy interpretation was based on the results of condensed images and time activity curves. A total of 108 oropharyngeal transits were analyzed. First we determined the most appropriate volume (1 or 3 ml) of paté, omelette, and egg white (i.e., the volume with the least residual oropharyngeal activity). Buccal or pharyngeal bolus retention occurred significantly less frequently with 1 ml paté than 3 ml (p = 0.03) and also less frequently with 3 ml egg white than with 1 ml egg white (p = 0.03), and the mean buccal bolus retention index was lower using 3 ml omelette than 1 ml omelette (p = 0.03). Then we identified the most suitable of the three selected boluses. Both oral and pharyngeal residues were higher for paté (1 ml) than for omelette (p = 0.02 and 0.05), and pharyngeal residue was significantly lower for omelette (3 ml) than for egg white (3 ml) (p = 0.02). In conclusion, a 3-ml bolus of radiolabeled omelette seems to be the most suitable bolus for exploration of esophageal transit, and its use could enhance the potential of scintigraphy in the assessment of esophageal disorders.

Métastase pelvienne intramusculaire d’un carcinome différencié de la thyroïde

Authors report on a case of one intramuscular metastasis from a non-medullary differentiated thyroid carcinoma. Muscular metastasis are rare in this pathology. Moreover, body-scanning scintigraphic interpretation is difficult for the pelvic area. False-positive are numerous and a very precise topographical diagnosis is required to choose the best surgical approach. Authors propose a specific management of different imaging methods for such a metastatic site. They associate a CT scan and a multiplanar iodine and technetium scintigraphy.

Experienced Scintigraphers Contribute to Success of Minimally Invasive Parathyroidectomy by Skilled Endocrine Surgeons

Minimally invasive parathyroidectomy (MIP) has become the preferred surgical treatment for selected patients diagnosed with primary hyperparathyroidism (PHPT) at our tertiary-care center. Preoperative scintigraphy establishes the position of a parathyroid adenoma, dictates the incision site, and can minimize incision size and consequent tissue dissection. We reviewed our database and sought to identify factors that led to discordant preoperative imaging and operative findings and to assess the effect of experience on these findings. A retrospective review was performed on all patients with biochemically proven PHPT who underwent Tc-99m sestamibi scintigraphy and surgical intervention. Patient demographics, date of surgical intervention, scintigraphic localization, surgical findings, pre- and postoperative biochemical markers, histopathology, coexisting thyroid pathology, and 6-month follow up were recorded. Preoperative images that were discordant with operative findings were independently reviewed. Parathyroid scintigraphy was performed on 125 consecutive patients for PHPT between November 1999 and January 2002. Seventy-six patients had MIPs, 35 had standard cervical explorations, 11 had MIPs that were converted to standard cervical explorations, and three had surgery directed to an ectopic location. At 6-month follow-up 98.4 per cent were cured. Preoperative imaging and surgical findings were ipsilateral and concordant in 105 of 118 (89%) patients with parathyroid adenoma. The anatomic origin of an adenoma was predicted in only 83 of 118 (68%) patients. Most of the inaccurate scintigraphy readings occurred during the first 13 of the 26 months that MIPs were performed at our institution. Only two discordant cases occurred during the last 9 months of this period. Biochemical markers, prior neck operation, and concomitant thyroid pathology had no correlation with imaging sensitivity. Scintigraphic interpretation of smaller adenomas was less reliable; discordant cases were more common in small adenomas. Communication between endocrine surgeons and nuclear medicine physicians about the MIP technique and anatomic orientation of adenomas led to better scintigraphic localization as experience increased. Now that MIP by skilled endocrine surgeons is becoming the favored treatment for PHPT experienced nuclear medicine physicians may be the most important factor to achieve maximum success.

Use of nuclear medicine imaging: Scintigraphy in diagnosis of equine orthopedic disease

This study describes techniques, indications and findings of nuclear medicine imaging ? scintigraphy of 42 horses with acute and chronic lameness of unknown origin. Most horses showed increased uptake of 99mTc-methylene diphosphonate in the tarsal joint (linked to the osteoarthritis and distal tarsal synovitis), the distal sesamoid bones (linked to the navicular disease), proximal attaches of the musculus interoseus medius on the palmar/plantar region of the metacarpus or metatarsus (linked to the insertations desmopathie) and in the dorsal processes of thoracic vertebrae (linked to the kissing spine syndrome). The interpretation of scintigraphy appeared to be a more reliable and sensitive diagnostic method than radiography in diagnosing these equine orthopedic disease.

Influencia de diferentes observadores sobre la interpretación de la gammagrafía de perfusión pulmonar

The agreement in the interpretation of the scintigraphic images of pulmonary perfusion in the diagnosis of pulmonary tromboembolism (TEP) is not always the most adequate. The purpose of this study was to evaluate the degree of agreement by eight observers in the interpretation of these studies. The study population consisted of 180 studies with clinically suspected pulmonary embolism referred to our department for scintigraphic perfusion imaging from April 98 to September 99. The patients received an intravenous injection of 111-148 MBq (3-4 mCi) of 99mTc-macroaggregated albumin whereas the images were obtained in the six routine projections. The observers consisted of five nuclear medicine physicians and three residents who independently reviewed the scintigrams (low, intermediate and high probability). In a second step, the physicians performed consensus interpretations. The Kappa statistics was used to evaluate the degree of agreement between individual observer interpretations beyond that expected by chance alone. The mean value SEM for Kappa index was 0.58 0.02, with maximum and minimum values of 0.76 and 0.27 respectively. The interobserver variability was greater than expected. Except in two observers scans in the interpretation of images in the low and high categories showed minor discrepancies, whereas scans in intermediate probability showed the most important interobserver variations. The study manifests the importance of a uniform criteria in lung scintigraphic interpretation.

Reliability of DMSA for the diagnosis of renal parenchymal abnormality in children.

The objective of this study was to evaluate the variability of technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy interpretation by four nuclear medicine physicians for the diagnosis of renal parenchymal abnormality in children, and to compare variability among three different DMSA methods in clinical use: planar alone, single-photon emission tomography (SPET) alone, and planar with SPET. One hundred consecutive DMSA studies were independently interpreted 3 times by four participating nuclear medicine specialists from different departments and in random order. All scans were classified by the presence or absence of renal parenchymal abnormality using the modified four-level grading system of Goldraich. Indices of agreement were the percentage of agreement and the kappa statistic. Disagreement was analysed using children, kidneys and kidney zones (three zones per kidney). Using patients as the unit of analysis, agreement for planar and planar with SPET methods was 87%-88% (kappa 0.74) for the normal-abnormal scan classification. The corresponding agreement value for the SPET alone method was 78% (kappa 0.56). Similarly, substantial disagreement (disagreement > or = 2 categories) occurred in 2.5% and 1.3% of comparisons between observers for planar alone and planar with SPET, respectively, but in 5.2% of comparisons for SPET alone. These results did not vary appreciably whether interpretation of patients, kidneys or kidney zones was compared. It is concluded that the four experienced nuclear medicine physicians showed substantial agreement in the interpretation of planar alone and planar with SPET DMSA scintigraphic images. Interpretation of SPET DMSA images, without planar images, was significantly more variable than interpretation using the two other methods, disagreement occurring in more than 20% of comparisons. SPET DMSA scintigraphy, when used without planar images, does not provide a firm basis for clinical decision making in the care of children who may have renal damage. There is no apparent benefit of reduced variability from the extra provision of SPET data to nuclear medicine physicians who already have planar images.

Interpretation of scintigraphy of papillary cystadenoma lymphomatosum (Warthin's tumor) on the basis of histopathologic findings

Objectives The accumulation of 99mTc-pertechnetate in Warthin's tumor was estimated scintigraphically and histopathologically to determine the role of the epithelial component in scintigraphy. Study design Six cases underwent histopathologic examination and scintigraphic evaluation with 99mTc-pertechnetate. Histopathologically the tumors were classified into types according to the epithelial component and cystic space and compared with scintigraphic results evaluated by dynamic radioactive index and wash-out image. Results Histopathologic and scintigraphic observations showed an adequate correlation. Cases with a large epithelial component and poor cystic space showed a large radioactive index of dynamic scintigraphy and hot accumulation of wash-out image. Conclusions The scintigraphic results were chiefly due to the epithelial component, but the influence of the cystic space could not be disregarded.

Scintigraphy for diagnosis of avulsions of the origin of the suspensory ligament in horses: 51 cases (1980–1993)

Summary The medical records of 34 horses with a diagnosis of avulsion of the origin of the suspensory ligament that had been admitted to the veterinary medical teaching hospital between 1980 and 1993 were identified. In addition to clinical examination, 21 of 34 horses had scintigraphy and radiography performed during their examination. The usefulness of scintigraphy and radiography were assessed by comparing the initial findings reported in the medical record to those obtained in a retrospective review of the images. Thirty other horses with scintigraphic lesions of the proximal aspect of the third metacarpal/metatarsal bone but with a confirmed diagnosis other than avulsion of the suspensory ligament served as controls for lesion specificity. Scintigraphy (bone phase, n=21) revealed increased uptake in all horses in both reviews. Only 14 of 21 (67%) horses radiographed, however, had at least 1 lesion during the initial radiographic evaluation that was reported to be suggestive of avulsion. When the radiographs were reviewed retrospectively, the radiologist identified 18 of 21 (86%) horses with lesions consistent with avulsion. The interpretation of scintigraphy appeared to be a more repeatable and sensitive diagnostic method than radiography. However, though scintigraphy was sensitive in identifying inflammation of the proximal aspect of the metacarpal/metatarsal region, no specific diagnosis of avulsion could be made without coincident radiography; the specificity of scintigraphy in diagnosing avulsion of the suspensory ligament was only 41% (21/51). Radiography of the proximal aspect of the third metacarpal/tarsal bone was found to be falsely negative in 3 of 21 (14%) horses on retrospective evaluation and in 7 of 21 (33%) horses on initial evaluation, perhaps because radiographic signs of disease were subtle.

Myocardial perfusion scintigraphy in left bundle branch block: A perspective on the issue from image analysis in a clinical context

Among selected study populations, myocardial perfusion scintigraphy (MPS) in patients with left bundle branch block (LBBB) has been reported to show a low specificity for the diagnosis of coronary disease. However, the stress electrocardiogram (ECG) is nondiagnostic in this setting. To place this method in its appropriate clinical context, we evaluated MPS in all 69 consecutive patients with LBBB studied with scintigraphy for clinical reasons during a 40year period. Among 32 patients who underwent coronary angiography for clinical indications, per patient sensitivity, 96%; per vessel sensitivity, 84%, 50%, and 100% for left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) involvement, respectively; and per vessel specificity, 95% and 68% for LCX and RCA disease, respectively, were not significantly different from those previously published for the method in patients without LBBB. Although per patient specificity, 38%, and specificity, 39%, for LAD disease were low, the predictive value of a positive test remained relatively high (83%) owing to the small number of patients selected for angiography, in part based on scintigraphic findings, with normal coronary anatomy. In addition to a possible specific pathophysiologic cause related to LBBB, apparent perfusion abnormalities in the LAD distribution may relate to generic conditions that can make scintigraphic interpretation ambiguous, often in the anterior distribution, regardless of the clinical setting. Additionally, the apparent lack of scintigraphic specificity in the LAD distribution could relate in part to a selection bias toward catheterization of patients with induced scintigraphic abnormalities, especially in the LAD distribution. The low incidence of coronary-related events among patients with limited defects or normal scintigrams is additional evidence of the true scintigraphic specificity and the clinical value of the method in patients with LBBB. The selective occurrence of false positive scintigrams in the LAD territory among patients undergoing dynamic exercise compared with the more specific findings in the subgroup undergoing pharmacologic stress scintigraphy suggest that the latter method may be preferred in this patient population regardless of the cause of this finding. The results demonstrate the full spectrum of scintigraphy in patients with LBBB and support an important clinical role for the method in this difficult diagnostic subgroup.

IMPROVEMENT OF CHOLESCINTICRAPHY IN THE DIFFERENTIAL DIACNOSIS OF EXTRAHEPATIC BILIARY ATRESIA

The introduction of halogenated analogs of iminodiacetic acid (IDA) has increased the effectivity of cholescintigraphy in the differential diagnosis of extrahepatic biliary atresia (EHBA). We attempted to evaluate cholescintigraphy with regard to its potential in increasing the effectivity and predictive value in the diagnosis of EHBA. We studied 16 patients (3 with EHBA, weight = 2,45-6 kg, direct bilirubin 1,6-17,9 mg/dl) by 18 tests. 99mTc mebrofenin (n=5) and 99mTc lodida (n=13) were used as tracers in intermittant sequential scintigraphy to 24 hrs. The data were evaluated by a computer program to obtain 13 kinetic parameters, and were compared with the results of the conventional scintigraphic interpretation. The positive predictive value of the test increased to 80 % by measurement of the maximum intestinal activity, and to 100 % by evaluation of the hepatic tracer clearance. Combining the maximum intestinal activity with the hepatic tracer retention or clearance led to an effectivity and positive predictive value of 100 %. The examination of liver indices (± adjustment for background activity) had no value. Conclusions: An automated evaluation of data characterizing the excretion of halogenated IDA derivatives into the intestine has the potential of allowing the differentiation of EHBA from intrahepatic diseases with high probability. We plan to perform prospective studies on larger numbers of infants.

Clinical Outcome of Patients With a 'Low Probability' of Pulmonary Embolism on Ventilation-Perfusion Lung Scan

Lung ventilation and perfusion (V/Q) scintigraphy is usually indicated when pulmonary embolism (PE) is a suspected diagnosis. Typically, V/Q scintigraphic interpretation is reported as a "normal," "low," "intermediate," or "high probability" of PE. Although a "low probability" interpretation does not exclude the diagnosis of PE, it significantly reduces the likelihood. We retrospectively analyzed up to one year of follow-up in 90 patients who were clinically suspected of having PE, but in whom V/Q scintigraphy implied a low probability of PE. None of the 90 patients demonstrated clinical evidence of PE subsequent to the V/Q scan. Our findings suggest that significant pulmonary embolism is uncommon and that the clinical course appears to be predictable in patients with a low probability V/Q scan.

Can malt whisky be discriminated from blended whisky?: Peer commentaries and riposte: Good motivation but indifferent methods

<b>1331</b> <h3>Objectives</h3> To evaluate whether ¹³¹I-SPECT/CT may have an additional value over planar scan in identifying residues, local and distant metastases. <h3>Methods</h3> We studied 202 thyroidectomized DTC pts: 188 had ¹³¹I diagnostic and 14 post-therapeutic planar and SPECT/CT scan by an hybrid dual head gamma camera. An incremental value was assigned to SPECT/CT when it provided a better iodine uptake foci identification and interpretation, a more correct anatomic localization and characterization and a precise tumor lesion differentiation from physiological areas. <h3>Results</h3> Planar evidenced 151 foci in 70/202 pts, SPECT/CT 204 foci in 79/202 pts confirming those seen at planar, but also identified 37 occult foci in 14/70 pts; 6 occult foci were seen at SPECT/CT in 9/202 further pts negative at planar. SPECT/CT correctly characterized 58 foci unclear at planar and classified as neoplastic foci for which planar excluded malignancy, discriminating residues from lymph node metastases in the neck some of which adjacent to salivary glands missed by planar. SPECT/CT also detected occult metastases in mediastinum, abdomen/pelvis and bone. Globally, SPECT/CT detected more foci than planar in 11.4% of pts, including 4.5% completely negative at planar. Moreover, SPECT/CT had an incremental value in 65.8% of pts, modified therapeutic management in 34.1% of positive cases and clarified physiologic areas also avoiding unnecessary treatment in 16.4% of pts with only a focus. <h3>Conclusions</h3> ¹³¹I-SPECT/CT improved planar scintigraphy interpretation, reducing false positive and providing a higher accuracy in tumor identification; it was able to change therapeutic management defined by planar, including radioiodine dose, and resulted surgical planning reliable guide.

Review: A comparison of computerized quantitative methods for interpreting Tl-201 myocardial scintigraphs

Thallium-201 is a cation extracted very rapidly by myocardial cells from the coronary artery blood supply. Areas with insufficient blood flow (ischemic) or non-viable tissue (infarcted) do not pick up Tl-201. Images (scintigraphs) can be obtained from the radiation emanating from the myocardial walls. By visual methods scintigraphic interpretation is difficult. The object of this review is to present essential characteristics of some methods using computerized quantitative Tl-201 scintigraphy as well as their degree of sensitivity and specificity. Computerized evaluation offers the advantage of consistency of interpretation. Furthermore, many computerized methods achieve improved sensitivity and specificity over visual methods. The above technique may also be extended to other radionuclides.