Role of cardiac nuclear stress perfusion exam after computed tomographic coronary angiogram for evaluation of obstructive coronary artery disease in patients with chest pain.

BACKGROUND: Clinical workup for chest pain varies among institutions. Acute coronary syndrome (ACS) is the primary diagnosis to rule out in the differential diagnosis, due to its associated mortality and morbidity. Although studies have demonstrated efficacy of coronary computed tomographic angiography (CCTA) in diagnosis obstructive coronary artery disease (CAD), there is limited evidence in the clinical value of performing cardiac nuclear stress perfusion imaging [myocardial perfusion imaging (MPI)] exam in patients with chest pain after undergoing CCTA. We aim to evaluate clinical value of follow-up nuclear cardiac MPI in patients with chest pain who have undergone recent CCTA. METHODS: A total of 1,000 patients were evaluated in this IRB approved retrospective study who presented with symptoms of ACS. Patients who had elevated troponin or abnormal electrocardiogram (ECG) findings at initial presentation or prior to cardiac nuclear MPI were excluded from the study. All patients who underwent 64- or 320-detector row ECG-gated CCTA as well as a follow-up nuclear MPI. Patients who had diagnostics studies limited by artifact [e.g., suboptimal intravenous (IV) contrast bolus in CCTA, motion artifact on CCTA or MPI, etc.] were excluded. RESULTS: One hundred patients met the inclusion criteria. Patient demographics include average age 64.3 [32-89] years, 59 male, 41 females. Ninety-five/100 patients had at least one vessel with 50-70% coronary artery diameter stenosis measured on CCTA. There were no focal perfusion abnormalities identified on cardiac nuclear MPI in patients with less than 70% stenosis diagnosed on CCTA. Five percent of patients were identified with coronary arterial narrowing greater than 70% on CCTA and all 5 of these patients have evidence of abnormal cardiac nuclear stress test (perfusion abnormalities, chest pain, abnormal ECG). CONCLUSIONS: In low-to-intermediate risk patients with chest pain and evidence of non-critical coronary artery stenosis (i.e., less than 70% stenosis) diagnosed on CCTA, a follow-up cardiac nuclear perfusion imaging is of limited value.

Explorative Investigation of Whole-Lesion Histogram MRI Metrics for Differentiating Uterine Leiomyomas and Leiomyosarcomas.

OBJECTIVE: The purpose of this study is to assess the utility of texture analysis of multiple MRI sequences for the differentiation of uterine leiomyomas and leiomyosarcomas. MATERIALS AND METHODS: Seventeen leiomyosarcomas and 51 leiomyomas undergoing MRI before resection were included. Whole-lesion volumes of interest were placed on T2-weighted images, contrast-enhanced T1-weighted images, and apparent diffusion coefficient (ADC) maps. The diagnostic performance of histogram metrics was assessed. RESULTS: For T2-weighted images, significant differences were observed for mean, skewness, entropy, mean of the bottom 10th percentile (mean0-10), mean of the 10th through 25th percentiles (mean10-25), and mean of the 25th through 50th percentiles (mean25-50) (p ≤ 0.010). For T1-weighted contrast-enhanced images, significant differences were observed for mean0-10, mean10-25, and mean25-50 (p ≤ 0.045). For the ADC maps, no metrics showed a significant difference (p ≥ 0.067). Metrics with AUC greater than 0.8 were the mean0-10 (0.875), mean10-25 (0.863), mean25-50 (0.839), and mean (0.802) for T2-weighted imaging. The mean0-10, mean10-25, and mean25-50 for T2-weighted imaging all achieved greater AUCs than did the standard mean (p ≤ 0.038). Patients with leiomyosarcoma were significantly older than those with leiomyoma (p < 0.001; AUC = 0.866). At multivariable regression, significant independent predictors of leiomyosarcoma were patient age (p = 0.002) and T2-weighted imaging mean0-10 (p = 0.004), with a combined AUC of 0.955. Patient age achieved sensitivity of 82.4% and specificity of 92.2%; T2-weighted imaging mean0-10 achieved sensitivity of 82.4% and specificity of 74.5%. CONCLUSION: For whole-lesion histogram metrics obtained on various MRI sequences, T2-weighted images provided the highest, and ADC maps the lowest, performance for differentiating uterine leiomyomas and leiomyosarcomas. Metrics reflecting percentiles from the bottom half of the histogram distribution outperformed the standard mean. Models combining the T2-weighted imaging whole-lesion metrics and patient age achieved particularly high diagnostic performance. Although these findings require validation in larger studies, they have implications for facilitating improved treatment selection for these two entities.

Unusual accessory tendon connecting the hallucal extensors.

During routine dissection of an adult human cadaver, a suite of tendinous anomalies was discovered in the left hallucal region. Whereas the main tendon of the extensor hallucis longus muscle inserted normally, two accessory tendons were found coursing medial and lateral to the main tendon. The most lateral tendon originated from a supernumerary muscle belly and merged with the tendon of extensor hallucis brevis to form a composite tendon. The most medial tendon crossed the metatarsophalangeal joint and joined the composite tendon deep to the tendon of extensor hallucis longus. A terminal tendon, consisting of these three contributions, inserted upon the proximal hallucal phalanx. This variant likely arose due to atypical differentiation of the common extensor muscle mass during development, and is of particular significance to clinicians performing arthroscopy, tendon transfers, and other surgical procedures.