Single Photon Emission Computed Tomography Scans Research Articles

Disentangling Cognitive Defects in Chronic Depression and Repetitive Mild Traumatic Brain Injury

Patients with chronic depression may suffer from global cognitive defects. Here, we present a case with repetitive mild traumatic brain injuries (mTBI) that aggravated her depressive symptoms and exhibited atypical cognitive impairments. Her depressive symptoms had been resistant to a combination of SNRI and antipsychotics. The single-photon emission computed tomography scan showed asymmetric perfusion at medial temporal lobes - which has been found to be associated with somatic delusions in some other patients. Her cognitive impairment profile was also consistent with difficulty in inhibition and visual processing, as noted in medial temporal lobe dysfunction, but not commonly seen in chronic depression. After her depression was improved with antipsychotic medications, her specific cognitive impairments persisted. To conclude, repetitive mTBI might cause selective or atypical cognitive impairments that impact treatment responses in patients with depressive disorders.

Influence of a radioisotope from out of the effective field of view in a semiconductor single photon emission computed tomography scanner

Discovery NM 530c (CZT SPECT) is a new single photon emission computed tomography (SPECT) scanner using a cadmium-zinc-telluride (CZT) solid-state semiconductor detector technology. Due to multi-pinhole collimator design of this system, each CZT detector facing different direction and be able to get incidence radioactivity from radioisotopes (RIs) existing outside of effective field of view (EFOV). The purpose of this study is to verify its impact and compare it to a conventional Anger-type SPECT scanner (Discovery NM/CT 670 pro). We used (99m)TcO4(-) as radiation source and set it outside of the EFOV at several different positions (height and angle) and scanned by both the cameras. As a result, CZT SPECT got more influence compared to Anger-type SPECT. The impact was different according to its height. When using other RIs in CZT SPECT room, it is important to confirm the appropriate position against CZT SPECT during scan.

Quarter-Millimeter-Resolution Molecular Mouse Imaging with U-SPECT +

Limited spatial resolution of preclinical positron emission tomography (PET) and single-photon emission computed tomography (SPECT) has slowed down applications of molecular imaging in small animals. Here we present the latest-generation U-SPECT system (U-SPECT⁺, MILabs, Utrecht, the Netherlands) enabling radionuclide imaging of mice with quarter-millimeter resolution. The system was equipped with the newest high-resolution collimator with 0.25 mm diameter circular pinholes. It was calibrated with technetium-99 m point source measurements from which the system matrix was calculated. Images were reconstructed using pixel-based ordered subset expectation maximization (OSEM). Various phantoms and mouse SPECT scans were acquired. The reconstructed spatial resolution (the smallest visible capillary diameter in a hot-rod resolution phantom) was 0.25 mm. Knee joint images show tiny structures such as the femur epicondyle sulcus, as well as a clear separation between cortical and trabecular bone structures. In addition, time-activity curves of the lumbar spine illustrated that tracer dynamics in tiny tissue amounts could be measured. U-SPECT⁺ allows discrimination between molecular concentrations in adjacent volumes of as small as 0.015 μL, which is significantly better than can be imaged by any existing SPECT or PET system. This increase in the level of detail makes it more and more attractive to replace ex vivo methods and allows monitoring biological processes in tiny parts of organs in vivo.

Assessment of Inspection Technology of Dopamine Transporter Imaging with ¹²³I-Ioflupane

Imaging start time of single-photon emission computed tomography (SPECT) scan is recommended between 3 hours and 6 hours after injection of ¹²³I-ioflupane in Ioflupane clinical practice guidelines. But image includes the effect of physiological actions of the human body and the attenuation at 13.27 hours physical half-life of ¹²³I. Therefore, we evaluated the effect of the image by the elapsed time of imaging start time. Optimal cut-off frequency of Butterworth filter were examined phantom by normalized mean square error. Count was reduced by 23.1% in 5 hours, but cut-off frequency of Butterworth filter was 0.11 cycle/pixel in 0-5 hours from phantom data. Ten subjects (age 55-85 years) were injected with ¹²³I-ioflupane of 110-199 MBq into the vein only once. And we examined the specific binding ratio (SBR) in inspection of injection after 5. 5 hours and 3 hours. Decrease of counts value increased the coefficient of variance (CV) between 3 hours and 5.5 hours after injection, but the improvement of statistical noise by pre-processing filter reduced the CV. No significant difference in the result of SBR was found between 3 hours and 5. 5 hours after injection. Our results suggest that imaging start time of SPECT scan is recommended between 3 hours and 5.5 hours after injection of ¹²³I-ioflupane.

MIBI SPECT Scan and Ultrasonography in Preoperative Imaging of Primary Hyperparathyroidism

Objectives: In patients who have parathyroid adenoma, combination of ultrasonography and technetium Tc 99m sestamethoxyisobutylisonitrile scan (also called sestamibi or MIBI scan), which allows anatomic and functional information about parathyroid adenomas, is used commonly to maximize operative cure. The sensitivity of MIBI scan may be increased by adding single photon emission computed tomography (SPECT) and computed tomography (CT) as a combined MIBI-SPECT CT scan. We assessed the accuracy of ultrasonography and parathyroid MIBISPECT scan in detecting parathyroid adenoma and evaluated the potential benefit of the combined protocol of ultrasonography and MIBI-SPECT parathyroid scan. Methods: In 58 patients who had biochemical evidence of primary hyperparathyroidism, we retrospectively reviewed the preoperative ultrasonography and MIBI-SPECT scans. The results of these studies were correlated with surgical findings. Results: In the 58 patients, surgery showed that 43 patients (74%) had solitary parathyroid adenoma. The sensitivity, specificity and accuracy of MIBI-SPECT for parathyroid adenoma was (72%,80%,74%) and for ultrasonography (53%,60%,55%) respectively. The highest sensitivity is noted with the combination of MIBI-SPECT and ultrasonography (79%), . 9 adenomas (21%) were missed by both modalities. In the 20 adenomas that were missed by ultrasound 11 were detected by MIBI SPECT. Conclusion: The MIBI-SPECT had better performance than ultrasonography for parathyroid adenoma localization. The combined MIBI SPECT and ultrasonography has the highest sensitivity for parathyroid adenoma detection (79%). An alternative strategy may be to use MIBI-SPECT initially, and to proceed to ultrasonography only in patients with negative MIBI- SPECT. This may avoid many ultrasonography procedures.

Glow in the dark.

To highlight the importance of radiation safety and handling of radioactive secretions following 131I-meta iodobenzylguanidine (131I-mIBG) use in the treatment of neuroblastoma. We report a 4-year-old girl with stage 4 neuroblastoma, on whom's single-photon emission computer tomography (SPECT) scan we demonstrate four extra-corporal areas of radioactivity confirming radiation uptake in the four corners of her 'comfort blanket' that had been used to cover her during the scan. It transpired that she had been sucking on the four corners of this blanket. The patient's secretions remain radioactive for some time following scintigraphy, as evidence of radioactivity in the patient's comfort blanket. Radioactive uptake of 131I-mIBG in the salivary glands of patients has previously been reported. This illustrative case emphasizes that patient's secretions remain radioactive following treatment and highlights the importance of careful handling of radioactive secretions.

Old wine in new bottles: Validating the clinical utility of SPECT in predicting cognitive performance in mild traumatic brain injury

The neural underpinnings of cognitive dysfunction in mild traumatic brain injury (TBI) are not fully understood. Consequently, patient prognosis using existing clinical imaging is somewhat imprecise. Single photon emission computed tomography (SPECT) is a frequently employed investigation in this population, notwithstanding uncertainty over the clinical utility of the data obtained. In this study, subjects with mild TBI underwent 99mTc-ECD SPECT scanning, and were administered a brief battery of cognitive tests and self-report symptom scales of concussion and emotional distress. Testing took place 2 weeks (n=84) and 1 year (n=49) post-injury. Multivariate analysis (i.e., partial least squares analysis) revealed that frontal perfusion in right superior frontal and middle frontal gyri predicted poorer performance on the Stroop test, an index of executive function, both at initial and follow-up testing. Conversely, SPECT scans categorized as normal or abnormal by radiologists did not differentiate cognitively impaired from intact subjects. These results demonstrate the clinical utility of SPECT in mild TBI, but only when data are subjected to blood flow quantification analysis.

Bone scans are reliable for the identification of lumbar disk and facet pathology.

Study Design Surgeon survey. Objective To evaluate the reliability of bone single-photon emission computed tomography (SPECT) versus bone SPECT images co-registered with computed tomography (bone SPECT-CT) by analyzing interobserver agreement for identification of the anatomical location of technetium99m-labeled oxidronate uptake in the lumbar disk and/or facet joint. Methods Seven spine surgeons interpreted 20 bone scans: 10 conventional black-and-white tomograms (bone SPECT) and 10 color-graded bone SPECT-CT scans. Each surgeon was asked to identify the location of any diagnostically relevant uptake in the disk and/or facet joint between L1 and S1. Reliability was evaluated using the free-marginal kappa statistic, and the level of agreement was assessed using the Landis and Koch interpretation. Results Conventional bone SPECT scans and bone SPECT-CT scans were reliable for the identification of diagnostically relevant uptake, with bone SPECT-CT having higher reliability (kappa = 0.72) than bone SPECT alone (0.59). Bone SPECT and bone SPECT-CT were also reliable in identifying disk pathology, with kappa values of 0.72 and 0.81, respectively. However, bone SPECT-CT was more reliable (0.81) than bone SPECT (0.60) when identifying facet disease. Conclusions For the identification of disk pathology, it is reasonable to use either conventional bone SPECT or bone SPECT-CT; however, bone SPECT-CT is more reliable for facet joint pathology.

Nonlinear dual reconstruction of SPECT activity and attenuation images.

In single photon emission computed tomography (SPECT), accurate attenuation maps are needed to perform essential attenuation compensation for high quality radioactivity estimation. Formulating the SPECT activity and attenuation reconstruction tasks as coupled signal estimation and system parameter identification problems, where the activity distribution and the attenuation parameter are treated as random variables with known prior statistics, we present a nonlinear dual reconstruction scheme based on the unscented Kalman filtering (UKF) principles. In this effort, the dynamic changes of the organ radioactivity distribution are described through state space evolution equations, while the photon-counting SPECT projection data are measured through the observation equations. Activity distribution is then estimated with sub-optimal fixed attenuation parameters, followed by attenuation map reconstruction given these activity estimates. Such coupled estimation processes are iteratively repeated as necessary until convergence. The results obtained from Monte Carlo simulated data, physical phantom, and real SPECT scans demonstrate the improved performance of the proposed method both from visual inspection of the images and a quantitative evaluation, compared to the widely used EM-ML algorithms. The dual estimation framework has the potential to be useful for estimating the attenuation map from emission data only and thus benefit the radioactivity reconstruction.

A new PET resolution measurement method through Monte-Carlo simulations.

The aim of this study was to propose a novel method for image quality assessment in PET scanners through estimation of the modulation transfer function (MTF) of a plane source. The simulation was implemented using the previously validated Monte-Carlo model. A comparison of the proposed method with the more traditional technique, based on a line source, was also performed. The Geant4 application for tomographic emission (GATE) Monte-Carlo package was used for model development, and reconstructed images were obtained using software for tomographic image reconstruction (STIR) with cluster computing. A novel plane source consisting of a radioactive ((18)F-fluorodeoxyglucose) thin-layer chromatography plate was simulated (total source activity: 44.4 MBq) to assess image quality through the MTF. All images were reconstructed with the three-dimensional filtered back projection (FBP3DRP) and ordered-subsets expectation maximization (OSEM) reprojection algorithms. The MTFs obtained using ordered-subsets expectation maximization show, in all cases, that higher frequencies are preserved compared with those obtained using the FBP3DRP. In addition, the plane source method is less prone to noise than the conventional line source method (SD=0.0031 and 0.0203, respectively). The thin-layer chromatography-based plane source presented requires materials commonly found in a clinical environment and could be used to assess image quality in nuclear medicine departments and to further develop PET and single-photon emission computed tomography scanners through Monte-Carlo simulations.

Interventional therapy for human breast cancer in nude mice with 131I gelatin microspheres (¹³¹I-GMSs) following intratumoral injection.

IntroductionThe aim of this study was to investigate the effects of 131I gelatin microspheres (131I-GMS) on human breast cancer cells (MCF-7) in nude mice and the biodistribution of 131I-GMSs following intratumoral injections.MethodsA total of 20 tumor-bearing mice were divided into a treatment group and control group and received intratumoral injections of 2.5 mci 131I-GMSs and nonradioactive GMSs, respectively. Tumor size was measured once per week. Another 16 mice received intratumoral injections of 0.4 mci 131I-GMSs and were subjected to single photon emission computed tomography (SPECT) scans and tissue radioactivity concentration measurements on day 1, 4, 8 and 16 postinjection. The 20 tumor-bearing mice received intratumoral injections of 0.4 mci [131I] sodium iodide solution and were subjected to SPECT scans and intratumoral radioactivity measurements at 1, 6, 24, 48 and 72 h postinjection. The tumors were collected for histological examination.ResultsThe average tumor volume in the 131I-GMSs group on post-treatment day 21 decreased to 86.82 ± 63.6%, while it increased to 893.37 ± 158.12% in the control group (P < 0.01 vs. the 131I-GMSs group). 131I-GMSs provided much higher intratumoral retention of radioactivity, resulting in 19.93 ± 5.24% of the injected radioactivity after 16 days, whereas the control group retained only 1.83 ± 0.46% of the injected radioactivity within the tumors at 1 h postinjection.Conclusions131I-GMSs suppressed the growth of MCF-7 in nude mice and provided sustained intratumoral radioactivity retention. The results suggest the potential of 131I-GMSs for clinical applications in radiotherapy for breast cancer.

SU‐E‐I‐23: Design and Clinical Application of External Marking Body in Multi‐ Mode Medical Images Registration and Fusion

Purpose:To design an external marking body (EMB) that could be visible on computed tomography (CT), magnetic resonance (MR), positron emission tomography (PET) and single‐photon emission computed tomography (SPECT) images and to investigate the use of the EMB for multiple medical images registration and fusion in the clinic.Methods:We generated a solution containing paramagnetic metal ions and iodide ions (CT' MR dual‐visible solution) that could be viewed on CT and MR images and multi‐mode image visible solution (MIVS) that could be obtained by mixing radioactive nuclear material. A globular plastic theca (diameter: 3–6 mm) that mothball the MIVS and the EMB was brought by filling MIVS. The EMBs were fixed on the patient surface and CT, MR, PET and SPECT scans were obtained. The feasibility of clinical application and the display and registration error of EMB among different image modalities were investigated.Results:The dual‐visible solution was highly dense on CT images (HU&gt;700). A high signal was also found in all MR scanning (T1, T2, STIR and FLAIR) images, and the signal was higher than subcutaneous fat. EMB with radioactive nuclear material caused a radionuclide concentration area on PET and SPECT images, and the signal of EMB was similar to or higher than tumor signals. The theca with MIVS was clearly visible on all the images without artifact, and the shape was round or oval with a sharp edge. The maximum diameter display error was 0.3 ± 0.2mm on CT and MRI images, and 1.0 ± 0.3mm on PET and SPECT images. In addition, the registration accuracy of the theca center among multi‐mode images was less than 1mm.Conclusion:The application of EMB with MIVS improves the registration and fusion accuracy of multi‐mode medical images. Furthermore, it has the potential to ameliorate disease diagnosis and treatment outcome.

Condylar Hyperplasia

The objectives of this study were to compare demographic, clinical, radiographic, scintigraphic, and histologic differences between the 2 main types of condylar hyperplasia (CH) and to suggest a new therapeutic management based on such findings. This was a retrospective study based on 28 patients who presented either vertical (group 1) or horizontal (group 2) forms of CH and underwent surgical treatment. Every patient had a complete preoperative clinical and radiological examination as well as a single-photon emission computed tomography scan. A histologic analysis of each resected condyle was performed. These various parameters were then compared in the 2 patient groups. The mean age at time of the diagnosis was 25.8 years (range, 12-50 years), and there were 22 females and 6 males. Nineteen patients had the vertical form of CH, and 9 had the horizontal form. Scintigraphic analysis showed moderate to extensive radionucleotide uptake in cases with rapid growth. Four cases had negative single-photon emission computed tomography scan uptake, and all were vertical forms, but there was no statistically significant difference between the 2 groups. The histologic analysis showed both a global thickening of the cartilage cap and of the prechondroblastic cells layer with no statistically significant difference between the 2 groups. Condylar hyperplasia is a pathologic condition affecting mainly young females and whose origin remains unknown. Single-photon emission computed tomography scans as an indicator of the rapidity of the disease progress are essential in assessing the condylar hyperplasia and to guide the therapeutic approach.

Functional imaging: A necessary prerequisite to neuropsychological assessment

After traumatic brain injury, neuropsychological testing may be insensitive in documenting functional brain injury. Imaging with single-photon emission computed tomography (SPECT) and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scanning may identify brain injury that is missed on neuropsychological testing. A 27-year-old man had loss of consciousness after hydrogen sulfide exposure and a fall; he had markedly impaired function (short-term memory, sequential thinking, attention, and initiative), but neuropsychological testing showed only mild to moderate impairments. A 37-year-old woman had a whiplash injury and head trauma after an automobile accident; she had apprehension, dysphoria, word finding problems, impaired memory and concentration, and slowed thinking; neuropsy- chological testing was normal. In the man, SPECT scan showed decreased activity in the striatum, amygdala, and hippocampus bilaterally (decreased more in the right than left hemisphere); an FDG-PET scan showed markedly decreased metabolism in the left thalamus, heterogeneous abnormal uptake in the basal ganglia, and abnormally decreased metabolism in both temporal and inferior parietal lobes. In the woman, FDG-PET scan showed several regions of abnormal metabolic activity not restricted to single vascular territories and decreased activity in the left frontal lobe, left thalamus, and left caudate nucleus. Repeat neuropsychiatric testing in both patients showed cognitive and motor impairments that seriously limited routine activities of daily living. In summary, after traumatic brain injury associated with neuropsychological symptoms, SPECT and FDG-PET scanning may be more sensitive than neuropsychological testing in detecting objective signs of brain injury.

Feeling unreal: a functional imaging study in patients with Kleine-Levin syndrome.

Kleine-Levin syndrome is characterized by relapsing-remitting episodes of severe hypersomnia, cognitive impairment, apathy, derealization and behavioural disturbances. Between episodes, patients have normal sleep, mood and behaviour. Functional imaging studies performed in small series of patients with Kleine-Levin syndrome with visual or semi-quantitative, uncontrolled analysis yielded equivocal brain changes. Using whole brain voxel-based group analysis, we compared brain perfusion scintigraphy during and between episodes in consecutive patients with Kleine-Levin syndrome versus healthy control subjects and correlated perfusion changes with disease severity and symptoms, focusing on less studied but disabling symptoms, such as apathy and derealization. During asymptomatic periods, 41 patients (mean age of 22.3 ± 8.1 years, 56.1% male) and 15 age- and sex-matched healthy control subjects underwent single-photon emission computed tomography scanning with technetium-99m ethyl cysteinate dimer. Eleven patients repeated the test during a symptomatic period. Compared with controls, patients during asymptomatic periods had persistent hypoperfusion in the hypothalamus, the thalamus (mainly the right posterior part), the caudate nucleus, and cortical associative areas, including the anterior cingulate, (Brodmann area 25), the orbito-frontal (Brodmann area 11) and the right superior temporal cortices (Brodmann area 22), extending to the insula (P < 0.001 in all area). Two additional hypoperfused areas emerged during symptomatic periods (P < 0.001), located in the right dorsomedial prefrontal cortex (Brodmann area 8) and the right parieto-temporal junction (Brodmann areas 22 and 39). These two areas were more affected between episodes, when the mean episode duration was longer (r = -0.53; P < 0.001). The score for the Depersonalization/Derealization Inventory during symptomatic periods strongly correlated with the hypoperfusion of the right (r = -0.74, P < 0.001) and left (r = -0.59, P < 0.005) parieto-temporal junctions. No hyperperfusion was found. Because the parieto-temporal junction (including the angular gyrus) is involved in cross-modal association between somatosensory (body knowledge), auditory and visual information, the robust hypoperfusions and correlations observed in this area may underlie the striking derealization reported by patients during episodes. Defects in the dorsomedial prefrontal cortex may cause apathy. Persistent hypoperfusion in the diencephalic and associative cortical area during asymptomatic periods is a marker of the disease, suggestive of a scenario wherein patients compensate for these deficient circuitries.

Undetectable specific striatal [123I]-ioflupane binding in patients with parkinsonism

[123I]-Ioflupane single photon emission computed tomography (SPECT) is widely used to evaluate the impairment of the nigrostriatal pathway in patients with parkinsonism. We describe a patient with visually undetectable specific striatal [123I]-ioflupane binding in the striatum. Of the 950 [123I]-ioflupane SPECT scans of patients acquired in our department, only one did not show any visually detectable striatal binding. To investigate this issue, we described multimodality imaging in this patient, including a second [123I]-ioflupane SPECT with a higher dose of [123I]-ioflupane, a [18F]-fluoro-l-dopa positron emission tomography (PET), a new MRI and an FDG-PET. Clinical and imaging data (FDG-PET and MRI) led to a diagnosis of progressive supranuclear palsy (PSP). Visual analysis of the second [123I]-ioflupane SPECT performed with a higher dose of [123I]-ioflupane confirmed nearly undetectable specific striatal binding of the tracer. The [18F]-fluoro-l-dopa-PET striatal binding was decreased. After ruling out all technical issues, an undetectable specific [123I]-ioflupane striatal binding in a patient with parkinsonism can be a sign of severe DaT loss as we have observed in a case of probable PSP even with moderate motor signs.

Three-year clinical experience with VQ SPECT for diagnosing pulmonary embolism: diagnostic performance

Ventilation–perfusion (VQ) single-photon emission computed tomography (SPECT) comprised the administration of SmartVent (n=386) or Technegas (n=1564) and 200 MBq 99mTc-MAA. 1406 scans were normal, 462 showed PE, 61 showed a singular subsegmental mismatched defect, 21 scans were non-diagnostic. 26% of scans performed with Technegas showed PE, compared to 15% with SmartVent. VQ SPECT had a sensitivity of 95.7%, specificity 98.6%, positive predictive value 95.7%, negative predictive value 98.6%. A normal VQ SPECT scan implied a more than ten-fold lower cause-specific mortality (1 in 1406) than a scan showing PE (1 in 116). NPV of a negative D-dimer was 94.3%.

Evaluating the Role of Single-Photon Emission Computed Tomography in the Assessment of Neurotologic Complaints

We conducted a retrospective study to reexamine the value of single-photon emission computed tomography (SPECT) in the evaluation of patients with neurotologic complaints, and to assess the intra- and inter-radiologist variability of SPECT readings. Our study population was made up of 63 patients--23 men and 40 women, aged 34 to 91 years (mean: 59)--who had presented to a tertiary care otolaryngology practice and university hospital for evaluation of head trauma, sensorineural hearing loss, tinnitus, and/or vertigo. All patients had undergone brain scanning with SPECT during their evaluation, and almost all had also undergone magnetic resonance imaging (MRI) and standard computed tomography (CT). We compared the findings of all three imaging modalities in terms of their ability to detect neurotologic abnormalities. We found that detection rates were very similar among the three modalities; abnormalities were found in 24% of SPECT scans, 26% of MRIs, and 23% of CTs. Nevertheless, we did find that among 60 patients who underwent all three types of imaging, 13 (22%) exhibited areas of cerebral hypoperfusion on SPECT while their MRIs and CTs were read as either normal or nonspecific. In all, 18 of these 60 patients (30%) exhibited normal or nonspecific findings on all three types of imaging. In addition, when SPECT scans were read by the same radiologist at different times, different results were reported for 17 of the 63 scans (27%). Likewise, when SPECT scans were read by different radiologists, different results were reported for 21 of 63 scans (33%). We conclude that SPECT may be a valuable complementary diagnostic modality for making a comprehensive neurotologic evaluation and that it may detect abnormalities in some patients whose other imaging is read as normal. However, we did not find that SPECT was the most sensitive of the three modalities in neurotologic evaluation, as we had previously found in a preliminary study that the senior author (R.T.S.) published in 1996. In addition, with respect to our radiologists, both their intra- and inter-reader reliability was low, and we recommend additional study on this matter.

Radioguided Parthyroidectomy is Successful in 98.7% of Selected Patients

To examine an individualized approach to patients with primary hyperparathyroidism (PHPT) in an effort to identify factors that would differentiate patients who can be treated with radioguided parathyroidectomy (RP) from those that require more extensive parathyroid exploration (PE) using intraoperative parathyroid hormone (IOPTH) measurement and to compare rates of recurrent and persistent hypercalcemia. A total of 100 patients were retrospectively studied. Patients with positive single photon emission computed tomography (SPECT) scans underwent surgeon-performed sonography (SPS) followed by RP. Patients with negative or equivocal SPECT scans underwent PE utilizing SPS as a guide and IOPTH. The success rate, recurrence and persistence rates, and rate of bilateral exploration were compared. Seventy-five percent of patients with PHPT had a positive SPECT scan and underwent RP, whereas 25% of patients had a negative SPECT scan and underwent PE with IOPTH utilizing SPS as a guide. Persistent hypercalcemia was noted in 1 patient (1.3%) and recurrent hypercalcemia in 2 patients (2.6%) in the RP group, whereas no persistent hypercalcemia was noted in the group undergoing PE utilizing SPS and IOPTH. Overall, 89% of patients were cured with unilateral surgery. Patients with positive SPECT scans may undergo RP with an expected cure rate of 98.7%. Patients with negative SPECT scans should undergo SPS followed by PE using IOPTH and can expect a cure rate near 100%. Properly selected patients may undergo RP, with low rates of persistent (1.3%) and recurrent (2.6%) hypercalcemia.

Clinical Utility of SPECT Neuroimaging in the Diagnosis and Treatment of Traumatic Brain Injury: A Systematic Review

PurposeThis systematic review evaluated the clinical utility of single photon emission computed tomography (SPECT) in traumatic brain injury (TBI).MethodsAfter defining a PICO Statement (Population, Intervention, Comparison and Outcome Statement), PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria were applied to identify 1600 articles. After screening, 374 articles were eligible for review. Inclusion for review was focus on SPECT in the setting of mild, moderate, or severe TBI with cerebral lobar specificity of SPECT findings. Other inclusion criteria were comparison modalities in the same subjects and articles in English. Foreign language articles, SPECT studies that did not include comparison modalities, and case reports were not included for review.ResultsWe identified 19 longitudinal and 52 cross-sectional studies meeting inclusion criteria. Three longitudinal studies examined diagnostic predictive value. The first showed positive predictive value increases from initial SPECT scan shortly after trauma to one year follow up scans, from 59% to 95%. Subsequent work replicated these results in a larger cohort. Longitudinal and cross sectional studies demonstrated SPECT lesion localization not detected by CT or MRI. The most commonly abnormal regions revealed by SPECT in cross-sectional studies were frontal (94%) and temporal (77%) lobes. SPECT was found to outperform both CT and MRI in both acute and chronic imaging of TBI, particularly mild TBI. It was also found to have a near 100% negative predictive value.ConclusionsThis review demonstrates Level IIA evidence (at least one non-randomized controlled trial) for the value of SPECT in TBI. Given its advantages over CT and MRI in the detection of mild TBI in numerous studies of adequate quality, and given its excellent negative predictive value, it may be an important second test in settings where CT or MRI are negative after a closed head injury with post-injury neurological or psychiatric symptoms.