Regional cerebral blood flow in patients with sickle cell disease: study with single photon emission computed tomography.

OBJECTIVE: Neurological complications have been reported in patients with sickle-cell disease (SCD) using positron emission tomography (PET), magnetic resonance imaging (MRI), and computed tomography (CT), but not with single photon emission computed tomography (SPECT). The objective of this study was to investigate brain perfusion in the patients with SCD using SPECT after technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO), was administered and compare the findings with those of demography, physical examination, MRI and hematological profile. METHODS: The study involved 21 patients (12 males, 9 females, age at study 8-45 years) who were known to be having SCD for a duration of at least 5 years. The patients were not in acute crisis and had normal neurological assessments with no known history of stroke or transient ischemic episode or previous abnormal CT or MRI brain scan, and were right-handed. The brain SPECT was performed after intravenous injection of 740 MBq (20 mCi) 99mTc-HMPAO in adults or an appropriate dose in pediatric patients. The scans were visually interpreted by two nuclear medicine physicians and a decision was reached by consensus. An MRI done 3 months later was interpreted by a radiologist. The demographic data and hematological profile were obtained from the medical records of the patients. RESULTS: Of the 21 patients, 7 (age 11-22 years) had brain perfusion deficit mostly in the frontal lobe either alone or in combination with temporal and/or parietal lobe. The MRI was abnormal in 2 patients. The brain perfusion deficit was not associated with the demographic data of the patients or hematological profiles. CONCLUSIONS: The findings show that SPECT was useful in detecting brain perfusion deficit in SCD patients, and such an early detection may be clinically useful in the subsequent follow-up of such patients, since it is known that cerebral perfusion deficit can lead to silent infarct and/or overt stroke, and affect cognitive skills.

Sternal uptake on bone scintigraphy: age-related variants.

BACKGROUND: When reporting bone scans, it is important to distinguish between normal variants and skeletal pathology involving the sternum. There are only limited reports dealing with age-related normal variants of the sternum on bone scintigraphy. METHODS: We have studied the age-related variants of sternal uptake on bone scintigraphy. In a prospective study, 152 consecutive patients (66 males and 86 females) undergoing whole-body bone scanning, and who had no symptoms associated with the sternum, were evaluated for patterns of normal sternal uptake. Three hours after intravenous injection of (99m)Tc-methylene diphosphonate ((99m)Tc-MDP), whole-body bone scans in the anterior and posterior projections were acquired. Patterns of sternal uptake, including the sites and distribution of increased and decreased uptake, were analysed using age-related groups. RESULTS: Three patterns of tracer uptake in the sternum were recognized: a uniform pattern was most common in children (< or =12 years); a heterogeneous uptake pattern was frequently seen in adolescents, young adult and adult groups; and a segmented pattern was commonly seen in the geriatric group (>60 years). A predominant focal finding was a hot spot at the angle of Louis. In addition, there were focal spots of decreased tracer uptake in the lower sternum, just above the xiphoid process, and spots of increased tracer uptake in the body of the sternum. Such focal spots were not seen in subjects of less than 12 years of age. CONCLUSION: Evolutionary changes of the sternum appear to exist throughout life. There are age-related normal variants of sternal uptake on bone scintigraphy.

Ewing sarcoma of the rib with normal blood flow and blood pool imagings on a 3-phase bone scan.

Ewing sarcoma is the second most common pediatric malignant bone tumor. It usually presents as a hot spot on a 3-phase bone scan as a result of increased vascularity of the tumor and new bone formation. However, aggressive Ewing sarcoma can also appear as a cold lesion. We present the features of a Ewing sarcoma of the rib on a 3-phase bone scan in a child who was being investigated for rib fracture after trauma.

Correlation between transient ischemic dilatation (TID) and coronary artery disease in Saudi male patients.

OBJECTIVE: A high transient ischemic dilatation ratio (TID) for the left ventricle (LV) from a gated myocardial perfusion imaging (G-MPI) study is widely believed to be associated with significant coronary artery disease (CAD). We have investigated the relationship between TID and CAD for our male Saudi Arabian patient population. METHODS: In this retrospective study, all male Saudi Arabian patients who underwent a two-day G-MPI study using Tc99m MIBI during the year 2011 having a TID â©¾ 1.20 were included. Quantitative perfusion and gated parameters were obtained using Cedar Sinai's AutoQuant software version 3.0, 2003, Means of summed stress scores, summed rest scores and summed difference scores (SSS, SRS, SDS, respectively), stress and rest ejection fraction (EF) were calculated. Visual interpretation was performed to classify the perfusion as normal, fixed, mixed (fixed and reversible defects), single reversible or multiple reversible defects. Coronary angiograms were assessed as normal with no CAD, single vessel, two-vessel or three-vessel disease. Correlations between the TID and other parameters were studied using analysis of variance (ANOVA) with IBM-SPSS version 20. RESULTS: A total of 52 male patients had a high TID of ⩾1.20 (mean 1.30 ± 0.13). Ten patients had a SSS of 0-3 and 16 were classified as normal by visual assessment. Stress EF (mean 50.4 ± 12%) was lower than the rest EF (mean 56.6 ± 12.8%) with the difference being statistically significant (Students paired t-test, p = 0.001). Angiography results were available in 44 patients, 3 having a normal angiogram, 24 having three vessel disease, 7 having two vessel disease and 10 having one vessel disease. Five patients with normal perfusion and SSS = 0-3 had CAD as seen on a coronary angiography. CAD on coronary angiography showed a significant correlation with perfusion abnormalities as assessed by visual interpretation (p = 0.002). TID showed a significantly correlation with both perfusion abnormalities (p = 0.009), as assessed by visual interpretation, and with Summed difference scores, SDS (p = 0.000). CONCLUSION: A high TID on G-MPI was a very sensitive indicator of significant CAD. In patients with normal perfusion and high TID further workup is warranted.

Mean bone mineral density and frequency of occurrence of osteopenia and osteoporosis in patients on hemodialysis: a single-center study.

Chronic renal disease changes both quality and quantity of bone through multi-factorial influences on bone metabolism, leading to osteopenia, osteoporosis and increased risk of fracture. The objectives of our present cross-sectional study were to determine the mean bone mineral density (BMD) and frequency of occurrence of osteoporosis and osteopenia in Saudi patients on hemodialysis (HD) for longer than 1 year. Forty-two male and 78 female patients with age between 20 and 50 years were enrolled in this study. The BMD of the lumbar vertebral spine (LV) and the neck of femur (FN) were measured in all patients. Data were analyzed using SPSS version 17.0 software and the level of significance was considered as P <0.05. The mean BMD in the LV (L2-L4) was 1.155 ± 0.026 g/cm 2 in male and 1.050 ± 0.025 g/cm 2 in female patients (P = 0.016). The mean BMD in the FN was 1.010 ± 0.023 g/cm 2 in male and 0.784 ± 0.020 g/cm 2 in female patients (P = 0.00). Based on the World Health Organization criteria, 73.8% of the male and 44.9% of the female patients in our study had normal BMD (P = 0.002); 16.7% male and 28.2% female patients had osteopenia (P = 0.14), while 9.5% male and 26.9% female patients had osteoporosis (P = 0.01). This study showed a marked decrease in mean BMD in the cortical bone (FN) compared with trabecular bone (LV) (P = 0.00) as well as in female patients on HD compared with male patients (P = 0.016 for LV and P = 0.00 for FN).

A comparison of myocardial perfusion gated SPECT studies obtained at rest and after stress.

OBJECTIVE: To perform a comparison between post-stress and rest gated single-photon emission computer tomography (SPECT) myocardial perfusion imaging (MPI) studies to assess post-stress stunning and the variables underlying this phenomenon. SUBJECTS AND METHODS: This was a prospective study of 318 consecutive adult patients undergoing stress and rest gated SPECT using a 2-day (99m)Tc-tetrofosmin protocol. Bruce protocol treadmill stress (n = 93) or i.v. dipyridamole pharmacologic stress (n = 225) were used as stressors. Ejection fractions (EF) and left ventricular (LV) end-diastolic (EDV) and end-systolic volumes (ESV) were calculated using the Cedars Sinai Quantitative Gated SPECT software. Perfusion defects were visually scored using a 20-segment model to obtain summed stress scores. Statistical analysis was performed by applying paired t test and multi-regression. Statistically significant (p < 0.05) paired differences between post-stress and rest EF and ESV and type of stressing were noted. RESULTS: Analysis of patient groups based on the type of stress showed significantly low EF on post-stress studies for both treadmill and dipyridamole stressing and also significantly high ESV on post-stress studies for dipyridamole. Multi-regression analysis using differences in post-stress and rest EF, EDV and ESV as dependent and summed stress scores, type of stress, delay time, previous myocardial infarction and size of LV as independent variables showed statistically significant associations between high summed stress scores (>13) and size of post-stress LV for EDV and ESV differences. High volumes were noted on post-stress studies. The magnitudes of the observed differences were well within the reproducibility of LV volume calculations. CONCLUSIONS: Patients showing stunning had significant ischemia or a dilated LV. The stunning manifested as high EDV and ESV differences. The magnitude of the differences observed in EF and LV volumes were not clinically significant.