Thyroid nodules classified as atypia or follicular lesions of undetermined significance deserve further research: Analysis of 305 surgically confirmed nodules.

OBJECTIVE: The objective of the present study was to determine the malignancy risk for nodules categorised as atypia or follicular lesions of undetermined significance atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) and to investigate the predictors of malignancy. METHODS: All nodules diagnosed as AUS/FLUS on fine needle aspiration (FNAs) performed between January 2011 and December 2015 were retrospectively reviewed. Clinical data, ultrasonographic features, follow-up data and the final pathological results were recorded. After further exclusion, only nodules that underwent surgical excision were included in the final analysis. The malignancy rate and the range of malignancy rates were calculated. Clinical and ultrasound features were examined to determine the predictors of malignancy. RESULTS: During the study period, FNA was performed on 9938 nodules, and 1019 (10.2%) nodules were diagnosed as AUS/FLUS. After further exclusion, 976 nodules were evaluated. After the initial diagnosis of AUS/FLUS, 139 (14.2%) patients underwent surgery, 518 (53.1%) had repeated FNAs. A total of 305 (31%) had undergone surgical excision at different time points. For surgically confirmed nodules, the malignancy rate after the initial FNA was 34.5% (the lower and upper thresholds for the malignancy rate were 19.3% and 66.3%, respectively), and 37.9% after the repeated FNA. No ultrasound feature was determined as a predictor, whereas age (>55 years) was a predictor for malignancy. CONCLUSIONS: The overall malignancy rate for nodules diagnosed as AUS/FLUS and the malignancy rate for nodules that underwent repeated FNA after AUS/FLUS were higher than the expected malignancy rates of the National Cancer Institute. It is, therefore, suggested that the current recommendations should be reconsidered.

Unbiased Charged Circular CMUT Microphone: Lumped-Element Modeling and Performance.

An energy-consistent lumped-element equivalent circuit model for charged circular capacitive micromachined ultrasonic transducer (CMUT) cell is derived and presented. It is analytically shown and experimentally verified that a series dc voltage source at the electrical terminals is sufficient to model the charging in CMUT. A model-based method for determining this potential from impedance measurements at low bias voltages is presented. The model is validated experimentally using an airborne CMUT, which resonates at 103 kHz. Impedance measurements, reception measurements at resonance and off-resonance, and the transient response of the CMUT are compared with the model predictions.

Bilateral CMUT Cells and Arrays: Equivalent Circuits, Diffraction Constants, and Substrate Impedance.

We introduce the large-signal and small-signal equivalent circuit models for a capacitive micromachined ultrasonic transducer (CMUT) cell, which has radiating plates on both sides. We present the diffraction coefficient of baffled and unbaffled CMUT cells. We show that the substrate can be modeled as a very thick radiating plate on one side, which can be readily incorporated in the introduced model. In the limiting case, the reactance of this backing impedance is entirely compliant for substrate materials with a Poisson's ratio less than 1/3. We assess the dependence of the radiation performance of the front plate on the thickness of the back plate by simulating an array of bilateral CMUT cells. We find that the small-signal linear model is sufficiently accurate for large-signal excitation, for the purpose of the determining the fundamental component. To determine harmonic distortion, the large-signal model must be used with harmonic balance analysis. Rayleigh-Bloch waves are excited at the front and back surfaces similar to conventional CMUT arrays.

Low-dose histidine-tryptophan-ketoglutarate solution for myocardial protection.

The effect of histidine-tryptophan-ketoglutarate (HTK) solution for myocardial protection has been shown in experimental and clinical studies using long ischemic times and high dosages. In our study we compared myocardial protection in isolated coronary bypass with a short period of ischemia using low dosage HTK and cold crystalloid cardioplegia. Each group contained 21 coronary artery disease patients. Cardioplegic solutions were administered antegrade in 10 to 15 mL/kg in one shot. This dosage of HTK was lower than that mentioned in the literature. We measured malondialdehyde, lactate, creatine kinase, creatine kinase-MB, and troponin-I levels. Aortic clamping time in the HTK group 33.9 +/- 8.2 minutes, versus 36.2 +/- 11.3 minutes in the crystalloid cardioplegia group (P > .05). Levels of creatine kinase and malondialdehyde were lower in HTK group at 24 hours and 2 minutes, respectively. Lactate levels were lower in the crystalloid cardioplegia group at 2 minutes in the coronary sinus serum sample, but there were no statistically differences among ischemic serum markers in both groups. Only intervals between aortic clamping and cardiac arrest were statistically meaningful (HTK 63.3 +/- 14.7 seconds versus crystalloid cardioplegia 53.6 +/- 15.6 seconds, P = .044). Our study shows that use of low-dose HTK for short clamping time operations is as successful for myocardial protection as crystalloid cardioplegia. Longer times for fibrillation can be explained with the low levels of potassium in HTK solution, but this length did not cause a biochemical or clinical difference.

The role of pulmonary artery anatomy in repair of tetralogy of Fallot.

Pulmonary artery anatomy is the key factor that determines the type of surgical treatment required in tetralogy of Fallot. Despite the fact that routine primary repair is now done on infants, inadequate pulmonary artery size can dictate the need for staged surgical repair in even the oldest age groups. From October 1986 to October 1998, 361 patients at our clinic underwent surgery to correct tetralogy of Fallot. A total of 292 cases were treated with primary repair, 69 surgeries were palliative, and 30 of these 69 underwent corrective surgery. The Nakata index was used as a pulmonary artery index (PAI), and PAI< 200 was the criterion for requirement of two-stage repair. Of the 30 patients that underwent staged repair, the Blalock-Taussig shunt (BTS) procedure was used in 24; the remaining six patients had right ventricular outflow tract reconstruction (RVOTR). The mean age of all the palliative surgery patients was 3.4 years (range 6 months to 11 years), and of those who received corrective surgery was 5.5 years (range 2-12 years). These patients' PAI values were 181 +/- 37.5 mm2/m2 and 359 +/- 130.7 mm2/m2, respectively. The period between the two operations ranged from two months to four years. Mortality rates were 2.8 percent for palliative surgery as a whole, 4.1 percent for primary repair, and 16.6 percent for staged repair. Our policy with regard to corrective surgery for tetralogy of Fallot is to do primary repair regardless of a patient's age and weight, except in cases where the pulmonary artery anatomy is appropriate for the patient's body size.

Designing transmitting CMUT cells for airborne applications.

We report a new mode of airborne operation for capacitive micromachined ultrasonic transducers (CMUT), in which the plate motion spans the entire gap without collapsing and the transducer is driven by a sinusoidal voltage without a dc bias. We present equivalent-circuit-based design fundamentals for an airborne CMUT cell and verify the design targets using fabricated CMUTs. The performance limits for silicon plates are derived. We experimentally obtain 78.9 dB//20 µPa@1 m source level at 73.7 kHz, with a CMUT cell of radius 2.05 mm driven by 71 V sinusoidal drive voltage at half the frequency. The measured quality factor is 120. We also study and discuss the interaction of the nonlinear transduction force and the nonlinearity of the plate compliance.

Aorto-left ventricular communication arising from the left aortic sinus of Valsalva: echocardiographic diagnosis and surgical repair.

A rare case of aorto-left ventricular communication arising from the left aortic sinus is described. This is the first reported case, known to us, in which the diagnosis was established by two-dimensional echocardiography and angiocardiography and a successful surgical repair was accomplished.

Two discrete masses of leiomyomatosis in a patient, one extending to the right atrium.

Leiomyomatosis extending to the right side of the heart through the inferior vena cava (IVC) is an extremely rare neoplasm. Although it is pathologically classified as a benign neoplastic formation, its growth and recurrence rate makes its extirpation mandatory. In this case report, we describe a 57-year-old woman who presented with leiomyotosis extending from the IVC to the right atrium (RA). This patient had presented with uterine leiomyoma three years previously. The patient died in the operating theatre from hemostatic problems after surgical complications arising from the unexpected presence of a second tumor.

Reduced jugular venous oxygen saturation during rewarming from deep hypothermic circulatory arrest: cerebral overextraction?

Deep hypothermic circulatory arrest may impair cerebral cellular functions, and physiological parameters following circulatory arrest may deviate from the normal. The intention of this study was to monitor jugular venous oxygen saturation during cardiopulmonary bypass before and after deep hypothermic circulatory arrest. Jugular venous oxygen saturation were obtained on 18 patients by using a retrograde jugular vein catheter during replacement of the ascending aorta. Indications for operations were ascending aortic dilatation (n=15) and acute aortic dissection (n=3). Hypothermic cardiopulmonary bypass (233+/-60 min), cardioplegic arrest (105+/-37 min) and circulatory arrest (22+/-7 min) were utilized during the operations. Jugular venous oxygen saturation increased during hypothermia and decreased during rewarming. Compared with cooling, jugular venous oxygen saturation during the initial part of rewarming were significantly lower (87+/-5% vs. 97+/-1%, 89+/-4% vs. 95+/-2%, 81+/-4% vs. 87+/-5% at 16, 20 and 24 degrees C respectively, p<0.05). One patient required re-exploration because of bleeding. All patients were found neurologically normal before being discharged from the hospital (mean 14+/-7 days). In conclusion, jugular venous oxygen saturation is inversely related to the body temperature in patients undergoing hypothermic cardiopulmonary bypass. Significantly decreased jugular venous oxygen saturation during the initial part of rewarming may signify an increased cerebral extraction of oxygen.