Clinical Validation of a Predictive Model for the Presence of Cervical Lymph Node Metastasis in Papillary Thyroid Cancer.

BACKGROUND AND PURPOSE: Ultrasound is a standard technique to detect lymph node metastasis in papillary thyroid cancer. Cystic changes and microcalcifications are the most specific features of metastasis, but with low sensitivity. This prospective study compared the diagnostic accuracy of a predictive model for sonographic evaluation of lymph nodes relative to the radiologist's standard assessment in detecting papillary thyroid cancer metastasis in patients after thyroidectomy. MATERIALS AND METHODS: Cervical lymph node sonographic images were reported by a radiologist (R method) per standard practice. The same images were independently evaluated by another radiologist using a sonographic predictive model (M method). A test was considered positive for metastasis if the R or M method suggested lymph node biopsy. The result of lymph node biopsy or surgical pathology was used as the reference standard. We estimated relative true-positive fraction and relative false-positive fraction using log-linear models for correlated binary data for the M method compared with the R method. RESULTS: A total of 237 lymph nodes in 103 patients were evaluated. Our analysis of relative true-positive fraction and relative false-positive fraction included 54 nodes with pathologic results in which at least 1 method (R or M) was positive. The M method had a higher relative true-positive fraction of 1.46 (95% CI, 1.12-1.91; P = .006) and a lower relative false-positive fraction of 0.58 (95% CI, 0.36-0.92; P = .02) compared with the R method. CONCLUSIONS: The sonographic predictive model outperformed the standard assessment to detect lymph node metastasis in patients with papillary thyroid cancer and may reduce unnecessary biopsies.

Fat distribution and metabolic changes are strongly correlated and energy expenditure is increased in the HIV lipodystrophy syndrome.

OBJECTIVE: To examine the relationships between protease inhibitor (PI) therapy, body fat distribution and metabolic disturbances in the HIV lipodystrophy syndrome. DESIGN: Cross-sectional study. SETTING: HIV primary care practices. PATIENTS: PI-treated patients with lipodystrophy (n= 14) and PI-treated (n= 13) and PI-naive (n= 5) patients without lipodystrophy. MAIN OUTCOME MEASURES: Body composition was assessed by physical examination, dual-energy X-ray absorptiometry and computed tomography. Insulin sensitivity (SI) was measured using the insulin-modified frequently sampled intravenous glucose tolerance test. Lipid profiles, other metabolic parameters, duration of HIV infection, CD4 lymphocyte counts, HIV-1 RNA load and resting energy expenditure (REE) were also assessed. RESULTS: PI-treated patients with lipodystrophy were significantly less insulin sensitive than PI-treated patients and PI-naive patients without any changes in fat distribution (SI(22) x 10(-4) (min(-1)/microU/ml) versus 3.2 x 10(-4) and 4.6 x 10(-4) (min(-1)/microU/ml), respectively; P < 0.001). Visceral adipose tissue area and other measures of central adiposity correlated strongly with metabolic disturbances as did the percent of total body fat present in the extremities; visceral adipose tissue was an independent predictor of insulin sensitivity and high density lipoprotein cholesterol levels. REE per kg lean body mass was significantly higher in the group with lipodystrophy compared to the groups without lipodystrophy (36.9 versus 31.5 and 29.4 kcal/kg lean body mass; P < 0.001), and SI was strongly correlated with and was an independent predictor of REE in this population. CONCLUSIONS: Body fat distribution and metabolic disturbances are strongly correlated in the HIV lipodystrophy syndrome and REE is increased.

Frequency of ovarian cysts in patients with autosomal dominant polycystic kidney disease.

Extrarenal cysts occur in patients with autosomal dominant polycystic kidney disease (ADPKD) most frequently in the liver. Ovarian cysts have been reported in women with ADPKD, but their frequency has not been determined. Therefore, we analyzed the historical data in our database of 337 women with ADPKD and 199 of their unaffected female family members (NADPKD). In addition, we prospectively studied 25 nonpregnant, premenopausal women with ADPKD and 25 nonpregnant, premenopausal, age-matched control women recruited from the general population to assess the occurrence of ovarian cysts. No women in either the control or ADPKD groups were receiving exogenous estrogen or progesterone. All women underwent sonographic examination using a 5- or 7.5-MHz vaginal probe. A normal ovarian follicle was defined as a fluid-filled structure less than 2 cm in average diameter, and an ovarian cyst as one of 2 cm or greater. From the historical data, 28% of the women with ADPKD gave a history of ovarian cysts compared with 18% of the NADPKD women (P < 0.05). In the prospective study, the mean age of the women with ADPKD was not different from that of the control women (40.9 +/- 1.2 v 39.3 +/- 1.2 years; P = not significant [NS]). There was no difference in frequency of normal follicles found in women with ADPKD or controls (80% v 96%; P = NS), nor was there a difference in the frequency of ovarian cysts found in women with ADPKD or controls (12% v 12%; P = NS). There was no difference in the calculated ovarian volumes between the women with ADPKD and controls (9.9 +/- 2. 5 v 7.2 +/- 1.2 cm3). Among the women with ADPKD, there was no correlation between mean ovarian volume and mean renal volume, nor was there a significant relationship between the occurrence of hepatic cystic disease and ovarian cysts. Therefore, a prospective imaging study suggests that ovarian cysts have no increased frequency in women with ADPKD compared with women in the general population.

Association of total and central adiposity measures with fasting insulin in a biracial population of young adults with normal glucose tolerance: the CARDIA study.

OBJECTIVE: To determine the association of computed tomography (CT)-measured visceral adipose tissue (AT) and other measures of adiposity with fasting insulin in a biracial (African American and Caucasian) study population of young adults. RESEARCH METHODS AND PROCEDURES: The study population consisted of 251 young adults with normal glucose tolerance (NGT), ages 28-40 years, who were volunteers from the Birmingham, Alabama, and Oakland, California centers of the Coronary Artery Risk Development in Young Adults (CARDIA) study. RESULTS: In regression models with total adiposity measures (body mass index or dual-energy X-ray absorptiometry-measured percent fat), visceral AT (measured as a cross-sectional area in cm2) was generally a stronger predictor of insulin than overall adiposity in all race/gender groups (partial correlation coefficients ranging from 0.31 to 0.47) except for black men, in whom the associations were nonsignificant. Partial correlation coefficients between waist circumference and insulin, controlling for percent fat, were nearly identical to those between visceral AT and insulin in women and in white men. Analyses performed on 2060 NGT CARDIA subjects who were not in this study of visceral AT showed significant correlations of waist circumference with insulin in all race/gender groups, including black men, and that black men in the visceral AT study group were significantly leaner than other black male CARDIA subjects. DISCUSSION: We conclude that visceral AT was associated with fasting insulin in NGT participants in three of the four race/gender groups (black men excepted) and that waist circumference was a good surrogate for visceral AT in examining associations of central adiposity with fasting insulin.

Racial differences in amounts of visceral adipose tissue in young adults: the CARDIA (Coronary Artery Risk Development in Young Adults) study.

BACKGROUND: In several white populations, visceral adipose tissue (VAT) is a risk factor for development of type 2 diabetes and dyslipidemia. VAT can be accurately assessed by computed topography or magnetic resonance imaging, but is also estimated from anthropometric variables, such as waist-to-hip ratio, waist circumference, or sagittal diameter. To date, anthropometric variables have been used largely in whites and inadequate data are available to evaluate the validity of these variables in other groups. OBJECTIVES: The objectives of this study were to 1) determine whether amount of VAT in relation to total body fatness differs in different race and sex groups and 2) determine which anthropometric variables predict amount of VAT in different race and sex groups. DESIGN: We determined the amount and location of body fat, including assessment of VAT by computed tomography, in young adult white and black men and women participating in the 10-y follow-up of the CARDIA (Coronary Artery Risk Development in Young Adults) Study. RESULTS: Black men had less visceral fat (73.1+/-35.9 cm2) than white men (99.3+/-40 cm2), even when VAT was corrected for total body fatness. Black women were more obese than white women and thus had more visceral fat (75.1+/-37.5 compared with 58.6+/-35.9 cm2, respectively). This difference disappeared when corrected for total body fatness. CONCLUSIONS: Both waist circumference and sagittal diameter were good predictors of VAT in all groups. However, the nature of this relation differed such that race- and sex-specific equations will likely be required to estimate VAT from waist circumference or sagittal diameter.

Diagnosis of fatty infiltration of the liver on contrast enhanced CT: limitations of liver-minus-spleen attenuation difference measurements.

BACKGROUND: We investigated whether liver-minus-spleen (L-S) attenuation differences can accurately diagnose fatty infiltration of the liver on contrast-enhanced computed tomography (CT). METHODS: A group of 78 patients administered a fast injection (90-s duration) of 150 mL 60% ionic contrast was compared with 81 patients given a slow injection (152.5 s). The presence or absence of fatty infiltration of the liver was diagnosed by noncontrast CT. RESULTS: The L-S attenuation differences varied significantly, depending on both injection rate and timing of measurements. For the fast-injection group, the optimal L-S threshold for diagnosing fatty infiltration ranged from -43 to -33 Hounsfield units (HU) for early (79 s) and late measurements (106 s), respectively. For the slow-injection group, the optimal threshold ranged from -31 to -25 HU (80 and 112 s, respectively). In addition, sensitivity was not very high (range = 0.54-0.71) for either injection protocol at any measurement time because of significant overlap of L-S values between normal and fatty infiltration patients. Moderate and severe fatty infiltration were more reliably diagnosed than mild fatty infiltration by this method. CONCLUSIONS: Contrast injection rate and timing of measurements significantly influence the optimal L-S threshold for diagnosing fatty liver. This limits the clinical usefulness of such measurements.

Knee version associated with anterior knee pain.

Version of the knee in the presence and absence of anterior knee pain was evaluated by computed tomography in this study. Version of the knee is defined as the static rotation of the tibia with respect to the femur in full knee extension. Fourteen patients in whom conservative management for anterior knee pain failed were compared with 14 volunteers with no symptoms. Computed tomography images of the femoral condyles and tibial plateau were obtained with the knee extended. The angle between the bicondylar and posterior tibial axes was measured. This angle, representing external rotation of the tibia relative to the femur, was increased significantly in patients with symptoms (7 degrees) compared with volunteers with no symptoms (1 degree). This increased knee version identifies a unique morphologic characteristic of the knee with anterior pain.

Location of the femoral sulcus in the osteoarthritic knee.

Morphology of the distal femur is characterized in patients with osteoarthritis to identify an etiology for the high incidence of patellar till, subluxation, and failure noted in total knee arthroplasty. This study demonstrates that the sulcus of the trochlear groove is not located in the midline as traditionally represented, but is lateral to the midline in both osteoarthritic and normal knees. The significance of this is that the patella will presumably track lateral to the midline unless surgically realigned, contributing to the prevalence of patellar tracking problems associated with symmetric femoral components with centralized sulci used in contemporary total knee arthroplasty.

Femoral morphometry and anterior knee pain.

By computed tomography scan, morphology of the femur in 20 adult patients with anterior knee pain was compared with that of ten volunteers without knee pain to identify femoral characteristics associated with the painful patella. Anteversion, measured as the difference between the axis of the head-neck and the axis of the posterior condyles, was significantly greater in symptomatic adults (p < 0.01). Configuration of the distal femur and position of the patella relative to the femur were similar in each group. Adult anterior knee pain was, therefore, associated with increased anteversion without compensatory change in trochlear morphology or patellar orientation to the femur.

Version of the osteoarthritic knee.

Version of normal and osteoarthritic knees is evaluated by computed tomography in this study. Version of the knee is defined as the static rotation of the tibia with respect to the femur in full knee extension. It is measured as the difference between the transverse axes of the femoral condyles and tibia. The average knee version, or external rotation of the tibia with respect to the femur across the normal knee, was 0 degree. Version of the osteoarthritic knee was 5 degrees. Rotation of the tibia with respect to the femur across the extended osteoarthritic knee is a relationship that will affect the placement of components in total knee arthroplasty. This relationship should be addressed in alignment instrumentation and technique to avoid component malalignment in total knee arthroplasty.

Chronic changes in skeletal muscle histology and function in peripheral arterial disease.

BACKGROUND: Peripheral arterial disease (PAD) is associated with an impairment in exercise performance and muscle function that is not fully explained by the reduced leg blood flow during exercise. This study characterized the effects of PAD on muscle function, histology, and metabolism. METHODS AND RESULTS: Twenty-six patients with PAD and six age-matched control subjects were studied. Ten of the PAD patients had unilateral disease, which permitted paired comparisons between their diseased and nonsymptomatic legs. All PAD patients had a lower peak treadmill walking time and peak oxygen consumption than controls. Vascular disease (diseased leg in unilateral patients and the most severely diseased leg in bilateral patients) was associated with decreased calf muscle strength compared with control values. In patients with unilateral disease, the diseased legs had a greater percentage of angular fibers (indicating chronic denervation) and a decreased type II fiber cross-sectional area (expressed as percent of total fiber area) compared with the nonsymptomatic, or control, legs. In diseased legs, gastrocnemius muscle strength was correlated with the total calf cross-sectional area (r = 0.78, p < 0.05) and type II fiber cross-sectional area (r = 0.63, p < 0.05). Activities of citrate synthase, phosphofructokinase, and lactate dehydrogenase in all 26 PAD patients (most diseased leg) did not differ from control values. Despite a wide range in citrate synthase activity in PAD patients, activity of this enzyme was not correlated with muscle strength or treadmill exercise performance. CONCLUSIONS: In patients with PAD, gastrocnemius muscle weakness is associated with muscle fiber denervation and a decreased type II fiber cross-sectional area. In contrast, the PAD patients displayed substantial heterogeneity in muscle enzyme activities that was not associated with exercise performance. Denervation and type II fiber atrophy may contribute to the muscle dysfunction in patients with PAD and further confirm that the pathophysiology of chronic PAD extends beyond arterial obstruction.

Spontaneous improvement of intrathoracic masses diagnosed in utero.

The diagnosis and pregnancy outcome for 14 fetuses with sonographically detected chest masses were reviewed retrospectively. Six lesions became smaller or less apparent during gestation or resolved between antenatal and perinatal imaging studies; these included all three types of cystic adenomatoid malformation (CAM), as well as one case of pulmonary sequestration (PS). This information is extremely important in counseling patients in the second trimester who are considering termination of pregnancy. The poor prognosis traditionally assigned to type II and type III CAM needs changing to reflect the phenomenon of improvement with excellent long-term outcomes. Sonographic indicators of poor outcome were polyhydramnios, hydrops or marked cardiac deviation.

CT of melanoma liver metastases: is the examination without contrast media superfluous?

The current method of evaluating hypervascular liver metastases with CT includes both contrast enhanced and unenhanced studies. The necessity of performing both examinations for the detection of liver metastases in the workup of malignant melanoma has not been specifically addressed. This study evaluates potential additional information derived from an unenhanced examination of the liver. We studied 55 patients with malignant melanoma who had both contrast enhanced and unenhanced CT examinations performed during the workup and staging of their disease. Sixteen patients had 89 measurable liver lesions seen on enhanced CT. Three patients had liver lesions that were too numerous to accurately measure. Unenhanced CT demonstrated only 62% of the measurable lesions. All liver lesions seen on the unenhanced images were identified on the enhanced studies. Only one metastasis was found to be comparatively smaller on the enhanced examinations. The unenhanced examinations detected no additional lesions. It is reasonable to perform only an enhanced examination during the workup and staging of malignant melanoma liver metastases.

Linear echoes in the fetal cisterna magna.

Linear echoes are seen in the fetal cisterna magna, (CM) on obstetrical sonography. These echoes often are paired, joining as they descend toward the base of the posterior fossa. Histologic correlation suggests that these echoes are most consistent with dural folds, which likely represent the inferior attachment of the falx cerebelli. A prospective series of 322 prenatal studies was performed in which the sonographer was asked to look for the linear echoes in the cisterna magna and image them. Linear echoes were identified in 84% of all fetuses studied. Identification of these echoes was dependent on CM size, in that they were seen less commonly when the CM was less than 3 mm in diameter. However, their identification was not dependent on gestational age. In addition, 18 fetuses with Dandy Walker cyst or Dandy Walker variant were evaluated and in 16 linear echoes were not seen. We conclude that recognition of normal anatomy within the fetal brain, specifically the fetal CM, is helpful for identifying abnormalities in the size of the CM, whether large or small.

Kleeblattschadel anomaly. In utero sonographic appearance.

Four cases of Kleeblattschadel demonstrated on prenatal ultrasound examinations are reported. Five additional cases from the literature are reviewed. Sonographic features include enlarged trilobed skull, hydrocephalus, polyhydramnios, and frequent association with thanatophoric dwarfism. The most common error in diagnosis was misinterpretation of this skull anomaly as encephalocele.

Abdominal wall CT: a pictorial essay.

Abdominal CT demonstrates clearly the anatomy of the abdominal wall. This radiographic technique may provide valuable information when pathology is suspected in this region or in the adjacent peritoneum. The muscles, subcutaneous tissues and vascular structures of the abdominal wall should be examined thoroughly when reading routine abdominal CT films. This paper reviews abnormalities identified involving the abdominal wall including hernias, masses, vessels, hematomas, abscesses, ascites, neuromuscular diseases and miscellaneous entities.

Effects of cycloheximide administered in conjunction with nicotine on retention of a passive avoidance task in mice.

Retention of a passive avoidance task was studied in mice given either cycloheximide or cycloheximide in combination with nicotine. Two similar experiments were conducted: In the first experiment, the effects, of these drugs were studied in inbred C57Bl/6J mice. In the second experiment, the effects of these drugs were studied in genetically heterogenous mice. Cycloheximide was found to have a deleterious effect on retention of the passive avoidance task. Larger doses of cycloheximide were found to be necessary to disrupt memory in heterogenous mice than in C57Bl/6J animals. Nicotine, when administered in conjunction with cycloheximide, abolished the memory disruptive effects of cycloheximide. The results of these experiments are discussed in terms of a time-dependent consolidation model of memory storage.