Free-breathing 3D whole-heart black-blood imaging with motion sensitized driven equilibrium

Purpose:

To automatically analyze the time course of collateralization in a rat hindlimb ischemia model based on signal intensity distribution (SID).

Materials and Methods:

Time‐of‐flight magnetic resonance angiograms (TOF‐MRA) were acquired in eight rats at 2, 7, and 21 days after unilateral femoral artery ligation. Analysis was performed on maximum intensity projections filtered with multiscale vessel enhancement filter. Differences in SID between ligated limb and a reference region were monitored over time and compared to manual collateral artery identification.

Results:

The differences in SID correlated well with the number of collateral arteries found with manual quantification. The time courses of ultrasmall (diameter ?0.5 mm) and small (diameter ≈0.5 mm) collateral artery development could be differentiated, revealing that maturation of the collaterals and enlargement of their feeding arteries occurred mainly after the first week postligation.

Conclusion:

SID analysis performed on axial maximum intensity projections is easy to implement, fast, and objective and provides more insight in the time course of arteriogenesis than manual identification. J. Magn. Reson. Imaging 2012;379‐386. © 2011 Wiley Periodicals, Inc.

     

Plasma levels of asymmetric dimethylarginine in patients with biopsy-proven nonalcoholic fatty liver disease

Asymmetric (ADMA) and symmetric dimethylarginine (SDMA) are produced by breakdown of proteins that have been methylated posttranslationally at an arginine residue. Plasma levels of ADMA are elevated in insulin resistance states. Nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance and varying degrees of hepatic dysfunction. Because ADMA is metabolized in the liver, we hypothesized that ADMA levels will be high in patients with NAFLD as a consequence of hepatic dysfunction and insulin resistance. Plasma levels of ADMA, SDMA, total homocysteine, glucose, and insulin were measured in nondiabetic patients with biopsy-proven NAFLD (11 steatosis and 24 nonalcoholic steatohepatitis) and 25 healthy subjects. Plasma ADMA levels were significantly higher (P = .029) in patients with biopsy-proven NAFLD (0.43 ± 0.21 μmol/L) compared with controls (0.34 ± 0.10 μmol/L). However, when adjusted for insulin resistance (homeostasis model assessment), the difference between 2 groups was not evident. Plasma SDMA levels were similar in all 3 groups. Plasma levels of ADMA were positively correlated with plasma total homocysteine levels (P = .003). Plasma levels of SDMA were negatively correlated with estimated glomerular filtration rate (P = .016) and positively correlated with plasma total homocysteine levels (P = .003). The ratio of ADMA/SDMA was positively correlated with body mass index (P = .027). Elevated plasma concentrations of ADMA in biopsy-proven NAFLD were primarily related to insulin resistance. Hepatic dysfunction in NAFLD does not appear to make significant contribution to changes in plasma methylarginine levels.     

Peritoneal Tuberculosis: Laparoscopic Patterns and Its Diagnostic Accuracy

We report laparoscopic findings in 38 proven cases of peritoneal tuberculosis. The laparoscopic appearances can be classified into three types: thickened peritoneum with miliary yellowish white tubercles with or without adhesions (n = 25), only thickened peritoneum with or without adhesions (n = 8), and fibroadhesive pattern (n = 5). Biopsies were avoided from fibroadhesive lesions due to risk of complications. Visual diagnosis was accurate in 95% of patients. In comparison, in 27 (82%) of 33 patients, the examination enabled a histologic diagnosis to he made on the basis of typical granulomas. The combined use of guinea pig inoculation and culture isolated Mycobacterium tuberculosis in six (37.5%) of 16 patients. Mycobacteria were scarcely (3%) seen on histological sections. We conclude that, although target biopsy is an effective method of obtaining an early diagnosis of peritoneal tuberculosis, chemotherapy may be started on the basis of visual laparoscopic appearances alone.     

Estimation of noise level and signal to noise ratio of laplacian electrocardiogram during ventricular depolarization and repolarization

Body surface Laplacian ECG (LECG) has demonstrated its enhanced capability to localize cardiac electrical sources closest to the recording site. The aim of the present study was to evaluate the noise level and signal to noise ratio (SNR) in the LECG as compared to the potential ECG (PECG). Such evaluation is important to determine the applicability of the LECG to localizing and imaging of cardiac electrical activity in an experimental setting. Experimental studies were conducted in six healthy men. A 150-channel PECG was recorded from the anterolateral chest and the LECG was estimated using the finite difference algorithm. The noise level in the PECG and LECG was evaluated using multiple estimation protocols. The signal level during ventricular depolarization and repolarization was also estimated, and the corresponding SNR was calculated. Different filtering techniques were examined to evaluate their effects on the noise level and SNR of the LECG and PECG. The experimental results indicate that with basic signal processing techniques (baseline adjustment, three-point moving average filter, and Wiener spatial filter), the SNR of the LECG is about 30-40% of that of the PECG. Furthermore, the SNR estimated during ventricular depolarization is about three times that obtained during ventricular repolarization for the PECG and LECG. The present study indicates that the LECG derived from the PECG using a local finite difference estimation procedure has satisfactory SNR during the periods of ventricular depolarization and repolarization, and suggests the feasibility of estimating the LECG from the recorded PECG in human subjects in an experimental setting.     

In vivo notch reactivation in differentiating cochlear hair cells induces sox2 and prox1 expression but does not disrupt hair cell maturation

COVER PHOTOGRAPH: Lineage tracing of Prox1 expressing inner ear cochlear cells in Prox1CreEGFP/+; Rosa26‐EYFPloxp/+ mice at P23. All cochlear hair cells are labeled with calbindin in red. EYFP in green historically records the cochlear cells experiencing Prox1 expression during the development, which include hair cells and supporting cells (both inside and outside the organ of Corti). From Liu et al., Developmental Dynamics 241:684–696, 2012.     

Primary papillary carcinoma of the thyroglossal duct cyst--a case report

Thyroglossal duct cyst is the most common developmental anomaly of the thyroid gland, presenting as a mid line neck swelling. Malignancy arising in them is a rare event, with papillary thyroid carcinoma being the commonest. Thyroglossal duct cyst carcinomas are usually asymptomatic and are not suspected preoperatively in most instances, hence the need for surgical excision and careful pathological examination of these cysts. We present a case of a 57 year old lady who underwent a Sistrunk procedure for the removal of thyroglossal duct cyst, which was responsible for a progressive mid line neck swelling of 2 months duration. The thyroid gland was normal. Histological examination of the excised cyst showed a papillary thyroid carcinoma arising in the thyroglossal duct cyst. Long term survival of patients with thyroglossal duct cyst carcinoma is excellent.     

Spinal cord injuries in older children: is there a role for high-dose methylprednisolone?

We present a retrospective case series of 15 children (aged 8-16 years) with blunt traumatic spinal cord injury who were treated with methylprednisolone as per the National Acute Spinal Cord Injury Study protocol. Of all patients, 12 (80%) were male. Causes were sports injuries (n = 9), motor vehicle crashes (n = 2), and falls (n = 4). Most injuries were nonskeletal (n = 14), and all patients had incomplete injury of the spinal cord. The most common location of tenderness was cervical (n = 7). Of the 15 patients, methylprednisolone was initiated within 3 hours in 13 patients and between 3 and 8 hours in 2 patients. All patients received the medication for 23 hours as per the National Acute Spinal Cord Injury Study protocol. Of the 15 patients, 13 recovered completely by 24 hours and were discharged with a diagnosis of spinal cord concussion. One patient had compression fracture of T5 and T3-T5 spinal contusion but no long-term neurological deficit. One patient was discharged with diagnosis of C1-C3 spinal cord contusion (by magnetic resonance imaging) and had partial recovery at 2 years after injury. All patients with a diagnosis of cord concussion had normal plain films of the spine and computed tomographic and magnetic resonance imaging findings. None of the patients had any associated major traumatic injuries to other organ systems. The high-dose steroid therapy did not result in any serious bacterial infections.     

Cytopathology of uncommon malignant renal neoplasms in the pediatric age group

Malignant renal neoplasms are common solid tumors in pediatric oncology practice. These include the common Wilms' tumor/nephroblastoma and the uncommon neoplasms such as clear-cell sarcoma of the kidney (CCSK), rhabdoid tumor, renal-cell carcinoma, and others. The aim of this study was to describe in detail the cytopathological features of the histopathologically proven uncommon pediatric renal tumors. Aspirates from Wilms' tumor, which are mesenchyme predominant, show clusters of spindle cells associated with the matrix material. Evidence of rhabdomyoblastic differentiation may be present. CCSK, classic subtype, is characterized by round to oval cells arranged perivascularly and also in sheets and clusters intimately associated with a metachromatic matrix mucopolysaccharide material better appreciated in May-Grunwald-Giemsa (MGG)-stained smears. The cells also have more abundant cytoplasm and may show nuclear grooves. Spindle-cell pattern of CCSK is difficult to diagnose on aspiration cytology. Renal-cell carcinoma of childhood shows similar cytological features as its adult counterpart. Rhabdoid tumor of the kidney is characterized by a monomorphic population of cells with abundant cytoplasm, eccentric nuclei with prominent nucleoli. Intrarenal yolk sac tumor is a rare neoplasm and shows severely pleomorphic cells on aspiration.Awareness of these entities is important for the practicing cytopathologist. Further, non-Wilms' renal malignant neoplasms must be distinguished from the common Wilms' tumor so that appropriate chemotherapy protocols may be instituted in cases where the tumor is in an advanced stage of malignancy.     

Fine-needle aspiration in the evaluation of thyroid lesions in children

The role of fine-needle aspiration (FNA) cytology in the evaluation of thyroid lesions in not as well established in children when compared with adults. Hence we aimed to ascertain the utility and limitations of FNA in childhood thyroid lesions. This was a retrospective analysis of all thyroid FNA performed in children less than 14 years of age over a 4-year period (2005-2009). Histopathological follow-up was available in six cases. A total of 77 cases were included in the analysis. The most common cytological diagnosis was lymphocytic thyroiditis (49.3%), followed by colloid goiter (18.2%), hyperplasia (10.4%), and benign aspirate (7.8%); malignancy was identified in six cases (7.8%). Of these six cases, three were papillary thyroid carcinoma. There was one false-positive case reported as a Hurthle-cell neoplasm, which on histology showed Hashimoto's thyroiditis. One case each of rhabdomyosarcoma and spindle epithelial tumor with thymus like differentiation was wrongly diagnosed as thyroid neoplasm, NOS, and medullary carcinoma (spindle variant), respectively. The overall diagnostic accuracy was 98.6% with 100% sensitivity, 98.6% specificity, 80% positive predictive value, and 100% negative predictive value. FNA is extremely valuable in the initial evaluation of thyroid swelling in children. Rare neoplasms masquerading as thyroid nodules in children can pose difficulties in diagnosis; however, papillary carcinoma is easily recognized. In lymphocytic thyroiditis, it provides a tissue diagnosis, thereby avoiding more invasive procedure for merely diagnostic purposes.