Comparing left ventricular ejection fraction measurement using cardiovascular magnetic resonance imaging.

PURPOSE: To compare the accuracy of cardiovascular magnetic resonance (CMR) imaging methods for measuring left ventricular ejection fraction with multiple-gated acquisition (MUGA). CMR imaging methods included in-line tracking, in-line automated tracking with manual adjustment (a semiautomatic technique), and manual drawing techniques. METHODS: Thirty patients were recruited for left ventricular ejection fraction (LVEF) assessment. The LVEF was measured by CMR imaging using in-line automated tracking, the semiautomatic technique, and manual contouring and segmentation. These methods were then followed by a MUGA scan. Results of all 4 methods were compared for LVEF percentage and measuring time. Repeated analysis of variance testing was used to determine any significant difference between the means of measuring the LVEF. A P value of less than .05 was considered statistically significant. RESULTS: The mean LVEF measured by CMR imaging using in-line automated tracking, a semiautomatic technique, and manual drawing were 52.9% (standard deviation [SD] 8.5), 62.3% (SD 8.1), and 62.2% (SD 7.8), respectively. The mean LVEF with the MUGA scan was 64.4% (SD 8.4). The MUGA scan, semiautomatic technique, and manual measurement using CMR imaging were statistically significantly different from the CMR imaging using in-line automated tracking for LVEF calculation (all P values < .01). DISCUSSION: Using in-line automated tracking, the end systolic volume was overestimated, which resulted in the underestimation of the LVEF. A therapeutic plan based on an inaccurate and low LVEF measurement could be dangerous because it might suggest a drug-related cardiotoxicity, and medication might be discontinued. CONCLUSION: A semiautomated technique with manual adjustment of the cardiac contours and basal slice selection in CMR imaging is time saving and comparable with the MUGA scan for the accurate documentation of LVEF.

The role of barium swallow pharyngoesophagography in the management of the globus pharyngeus: our ten years local experience of asian population.

Patients with globus pharyngeus referred for barium swallow pharyngoesophagography in a local hospital from 1/7/1999 to 30/6/2009 were identified. Their fluoroscopic images were reviewed, and their outcomes were used as gold standard. A total of 908 patients with globus pharyngeus were referred for barium swallow in the period. There were 783 patients with normal barium swallow and 125 patients with abnormal barium swallow findings. All patients aged below 30 years had normal barium swallow result and unremarkable follow up. The sensitivity and specificity of barium swallow were 25.6 and 97.5% respectively; and the positive predictive value and negative predictive value were 61.5 and 89.1% respectively. The overall accuracy was 87.6%. Barium swallow is of limited diagnostic value in patients with typical globus pharyngeus, and it is not recommended in these patients, especially with young age.

Imaging patterns of liver uptakes on PET scan: pearls and pitfalls.

OBJECTIVE: PET imaging is becoming increasingly universal, and therefore increased liver uptake is frequently encountered. The purpose of this article is to describe and illustrate the various morphological patterns of increased metabolic activity within the liver with an emphasis on the diagnostic pitfalls and potential limitations. CONCLUSION: Knowing the pitfalls of PET imaging, correlation with clinical background and findings from other imaging modalities are all important in the correct interpretation of increased hepatic activity on PET imaging.

Imaging features of colorectal liver metastasis in FDG PET-CT: a retrospective correlative analysis between CT attenuation and FDG uptake.

OBJECTIVES: Increasing scientific evidence supports the use of fluorodeoxyglucose positron emission tomography/ computed tomography (FDG-PET/CT) in the staging of colorectal carcinoma. A detailed and accurate characterization of tumor biology and imaging characteristics is therefore of paramount importance. The aim of our study was to determine whether CT attenuation, in Hounsfield units, was correlated with FDG uptake in colorectal liver metastasis. METHODS: The clinical and imaging data of patients from our institution with histologically proven colorectal carcinoma who were referred for PET/CT staging were reviewed. For the purpose of our study, we included only those patients who had undergone dual-time-point imaging. A total of 20 patients with 62 hepatic secondaries were identified. The perlesional CT attenuation (in Hounsfield units), FDG uptake (in standardized uptake values SUV 60 and SUV 120), and size (in cm) were determined. Correlation analysis using the Spearman rank correlation coefficient was carried out. RESULTS: A statistically significant positive relationship was observed between perlesional CT attenuation and SUV 60 (r=0.433, P=0.0004). A similar significant positive relationship was shown between perlesional CT attenuation and SUV 120 (r=0.414, P=0.0008). CONCLUSION: Our study suggested that, in colorectal liver metastasis, FDG uptake was positively correlated with CT attenuation. If a lesion appeared to be indeterminate because of apparently low FDG avidity, internal content must be taken into consideration to minimize misdiagnosis and false negatives. We proposed that such a relationship may be due to the mucinous contents of colorectal liver metastasis or degree of tumor necrosis. Further research, particularly on quantification of the extent of mucin production and tumor necrosis, may allow a more precise relationship to be drawn between CT attenuation and FDG uptake.

Diagnostic value of SPECT versus SPECT/CT in femoral avascular necrosis: preliminary results.

OBJECTIVE: With the advent of single-photon emission computer tomography/computed tomography (SPECT/CT), its applications and indications have to be evaluated clinically for a more efficient and cost-effective use in patient management. This retrospective study investigated the clinical value of conventional Tc MDP SPECT against SPECT/CT in diagnosing hip avascular necrosis (AVN). METHODS: This retrospective study evaluated all patients who underwent SPECT/CT during the period from 1 March 2008 to 31 July 2009 for possible femoral AVN for which MRI was contraindicated. The SPECT and SPECT/CT images were reviewed separately by two radiologists with different levels of experience in a double-blinded manner. The likelihood of AVN for each symptomatic hip was graded according to the level of confidence. Clinical outcome was considered as the gold standard. The sensitivity, specificity, and accuracy for SPECT and SPECT/CT by each radiologist was obtained and compared with the gold standard. The corresponding receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate the diagnostic power of SPECT against SPECT/CT. RESULTS: A total of 22 patients and 24 symptomatic hips were analyzed. Seven hips (29%) were confirmed to have AVN. The AUCs obtained from ROC for trainee radiologist for SPECT vs. SPECT/CT were 0.828 and 0.916, respectively. The AUC for specialist radiologist increased from 0.916 to 0.941 with CT. CONCLUSION: We concluded that SPECT/CT is beneficial for the improvement of AUC in ROC on the diagnostic of hip AVN compared with SPECT alone.

Renal length nomogram in Hong Kong Asian children: sonographic measurement and multivariable approach.

AIM: The purpose of our study was to build a multiple renal length nomogram for Hong Kong Asian children based on normal renal ultrasonography. METHODS: All children below the age of 13 years, who underwent ultrasonography in a local Hospital in Hong Kong from 23 September 2008 to 31 January 2009 due to melamine exposure were identified. RESULTS: A total of 3031 normal children were identified. Hong Kong Asian children have smaller kidneys as compared with the Western. Age, bodyweight and body height are the significant factors in the multiple nomogram model of renal length. The interaction between body ln(weight) (ln stands for natural logarithm) and age as well as body height and age are also significant in the model. CONCLUSION: Our study provides a practical multiple nomogram of renal length for Hong Kong Asian children.

Imaging in pediatric urinary tract infection: a 9-year local experience.

OBJECTIVE: Urinary tract infection (UTI) is a common disease entity in children, and a number of imaging options are offered for these patients. The purpose of our study was to retrospectively describe the (99m)Tc-labeled dimer captosuccinic acid (DMSA) renal scintigraphy, ultrasound, and micturating cystourethrography (MCU) findings over a 9-year period. MATERIALS AND METHODS: All children younger than 10 years old who presented to a local hospital in Hong Kong between July 1, 1997, and June 30, 2006, with culture-confirmed UTI and who subsequently underwent DMSA scintigraphy, ultrasound, and MCU were identified. For the purpose of this study, patients with underlying major congenital urinary tract abnormalities were excluded. DMSA scintigraphy was regarded as the gold standard for the diagnosis of renal scarring. DMSA scintigraphy, ultrasound, and MCU findings and clinical outcomes were reviewed and analyzed. RESULTS: A total of 583 children were included in the study. Of these, 432 children (74.1%) had normal findings on ultrasound and on MCU. Only 13 children (3%) of this group had renal scarring as shown on DMSA scintigraphy. The overall negative predictive value (NPV) for excluding renal scarring of combined ultrasound and MCU reached 97%. The NPV was 97.7% in the subgroup of patients 0 to 2 years old. CONCLUSION: For children younger than 2 years with UTI in the absence of underlying major congenital urinary tract abnormalities, we recommend that DMSA scintigraphy may be withheld if findings on both ultrasound and MCU examinations are normal.