Ultrasound Correlates Research Articles

Targeted Ultrasound of the Breast in Women With Abnormal MRI Findings for Whom Biopsy Has Been Recommended

This study was performed to identify characteristics of suspicious lesions seen on breast MRI that are most likely to have an ultrasound correlate and to determine how often the presumed ultrasound correlate actually corresponds to the MRI finding. From September 2005 through December 2007, targeted ultrasound was performed for 519 suspicious MRI-detected lesions in 361 women. Retrospective review was performed to determine lesion type (mass vs nonmass), lesion descriptors, lesion size, BI-RADS category, indication for MR examination, patient age, and biopsy outcome. The results of 80 follow-up MRI examinations among 154 cases with concordant benign results on ultrasound-guided biopsy were noted. A presumed ultrasound correlate was found in 290 (56%) of the 519 lesions with masses more likely than nonmass lesions to be seen with ultrasound (62% of masses and 31% of nonmass lesions). Increasing lesion size, assessment of BI-RADS category 5 versus BI-RADS category 4, rim enhancement in masses, and clumped enhancement in nonmass lesions were also significantly more likely to have an ultrasound correlate. On follow-up imaging in 80 benign, concordant ultrasound-guided biopsies, the sonographic lesion did not correspond to the MRI finding in 10. Nine of these 10 lesions underwent subsequent MRI-guided biopsy and five cancers were diagnosed. The MR characteristics of lesions most likely to be seen with an ultrasound correlate were mass versus nonmass, increasing size, and increased level of suspicion of the lesion. Clip placement and follow-up imaging after ultrasound-guided biopsy that yields benign concordant results should be performed to detect cases in which the presumed ultrasound correlate is inaccurate to detect unsuspected false-negative biopsies.

Clinicopathological Study of Regressed Testicular Tumors (Apparent Extragonadal Germ Cell Neoplasms)

Testicular germ cell tumors sometimes regress spontaneously and manifest exclusively by metastasis. We report our experience with extragonadal germ cell tumors of probable testicular origin to study the frequency of this entity, and clinical, ultrasound and histopathological correlations in a series of patients. A retrospective 16-year review of 1.2 million inhabitants in Spain revealed 17 with regressed testicular tumors treated at a total of 4 institutions. We analyzed clinical information, ultrasound features and histopathological characteristics of testicular lesions and metastasis, and highlight the main findings. A primary testicular origin was confirmed in all cases. This entity is more common than initially suspected since it accounts for 4% of consecutive germ cell tumors. Clinical manifestations varied according to metastatic site with an abdominal palpable mass (47% of cases), loin pain (35%) and transient testicular pain (29%) the most common complaints. No evidence of testicular neoplasms was found on physical examination in any case. Metastasis histology was nonseminomatous in 53% of cases, pure seminoma in 29% and mixed in 18%. The most common ultrasound features were calcifications in 65% of cases, hyperechogenic linear images in 59% and hypoechogenic nodular areas in 41%. Histological findings consisted of fibrotic areas in 100% of cases, hemosiderin deposits in 65%, seminiferous tubule atrophy in 59% and psammoma bodies in 29%. In testicular parenchyma or spermatic chord intratubular neoplasms and viable tumor foci were also noted (47% and 41% of cases, respectively). Spontaneous regression of a germ cell testicular tumor should be considered in each patient with extragonadal germ cell neoplasms. Ultrasound diagnosis of and surgical treatment for these primary testicular tumors appear critical to prevent relapse because residual disease develops in a significant proportion of cases.

Sonographic correlations with the new molecular classification of invasive breast cancer

Ultrasound is a useful adjunct to mammography for the characterisation and biopsy of solid breast lesions. Protein expression profiling of breast cancer has identified specific subgroups with potential clinical, biological and therapeutic implications. The aim of this study was to determine the ultrasound correlates of these novel molecular classes of invasive breast cancer. The ultrasound findings in 358 patients with operable breast cancer were correlated with the previously described protein expression classes identified by our group using immunohistochemical (IHC) assessment of a large series of breast cancer cases in which 25 proteins of known relevance in breast cancer were assessed, including hormone receptors, HER2 status, basal and luminal markers, p53 and e-cadherin. The proportion of occult lesions was not significantly different in the two groups. Significant differences were noted between the two groups expressing luminal epithelial markers and hormone receptors (1 and 2), including a greater proportion of ill-defined, irregular and distally attenuating tumours in group 2. Tumours characterised by c-erbB2/MUC1 expression, with weak hormone receptor positivity (group 3) were also more likely to be ill defined. Tumours expressing basal markers (group 5) were less likely to have an echogenic halo. The ultrasound features of breast cancer show areas of significant correlation with molecular classes of invasive breast cancer identified by IHC analysis. The biological reasons for these findings and their implications regarding imaging protocols require further study and may enable improved detection of these lesions.

Is there a way to diagnose spinal instability in acute burst fractures by performing ultrasound?

The aim of this study is to examine the predictive value of ultrasound diagnostics for the assessment of traumatic lesions of the posterior ligament complex (PLC) in burst fractures of the thoracolumbar spine. This was a prospective validating cohort study. Judgment about instability and treatment of burst fractures depends on the condition of the PLC. There have been some studies describing underdiagnosis of PLC injuries due to classification problems in ligamentary distraction type fractures. The gold standard for assessing these lesions is magnetic resonance imaging (MRI). Even then, there are often limits in contemporary operational availability and technical limitations of MRI. Ultrasound was described being an alternative. In a prospective study, 54 levels of 18 patients with acute burst fractures of the thoracic and lumbar spine have been examined by ultrasound and additional MRI scans preoperatively. The condition (intact vs. ruptured) of supraspinous ligament (SSL) and the interspinous ligament has been assessed for the ligaments separately. Hematoma below the SSL has also been evaluated as an indirect sign of an injured PLC. In all the patients the primary performed operative treatment was a posterior spinal instrumentation. Postoperatively the blinded results of the ultrasound procedures have been matched against intraoperative and MRI findings. Assessments of all target structures have been contributed to the calculation of the sensitivity and specificity of ultrasound. A total of 18 patients, 14 males and 4 females, with acute burst fractures have been qualified for inclusion in the study. The patients' mean age was 43.4 years. Comparing intraoperative findings with preoperatively performed investigations, ultrasound archived a sensitivity of 0.99 and a specificity of 0.75 (P < 0.05) to detect traumatic lesions to the PLC. As hypothesized the obtained predictive value using ultrasound correlates closely with intraoperative findings. Anyway MRI still seems to be the superior diagnostic method for examining the PLC. However, ultrasound can be considered to be an adequate alternative method in cases with contraindications for MRI such as ferromagnetic side effects, claustrophobia, availability or emergency diagnostics in multiple injuries.

Can Bedside Ultrasound Assist in Determining Whether Serum Creatinine is Elevated in Cases of Acute Urinary Retention?

There are no guidelines to determine which patients with acute urinary retention (AUR) require blood testing (i.e., serum creatinine) to assess for renal failure. To determine if hydronephrosis on bedside ultrasound correlates with an abnormal serum creatinine (Cr) level in cases of AUR. This was a prospective, observational study of subjects clinically diagnosed with AUR at two associated urban academic centers from October 2004 through August 2006. Emergency physicians completed a data form and performed a bedside ultrasound to determine the presence or absence of hydronephrosis. The data collected included suspected cause of AUR, amount of urinary output after Foley insertion, and blood test results. Follow-up was obtained by telephone and electronic medical record for 1 month. Standard statistics were employed. Among 96 enrolled subjects with AUR, 43 had a serum Cr level obtained on the initial visit, and 10 (23%; 95% confidence interval [CI] 11-36) of these had an elevated Cr (10% [95% CI 4-16] of the study cohort). The test characteristics of hydronephrosis on bedside ultrasound to detect elevation in Cr were a sensitivity, specificity, positive predictive value, and negative predictive value of 70%, 67%, 39%, and 88%, respectively. In cases of AUR, the prevalence of elevated creatinine is high, and hydronephrosis based on bedside ultrasonography does not correlate with elevation in creatinine.

Re-examining minimal luminal diameter relocation and quantitative coronary angiography – intravascular ultrasound correlations in stented saphenous vein grafts: methodological

Angiographic parameters (such as late luminal loss) are common endpoints in drug-eluting stent trials, but their correlation with the neointimal process and their reliability in predicting restenosis are debated. Using quantitative coronary angiography (QCA) data (49 bare metal stent and 44 sirolimus-eluting stent lesions) and intravascular ultrasound (IVUS) data (39 bare metal stent and 34 sirolimus-eluting stent lesions) from the randomised Reduction of Restenosis In Saphenous vein grafts with Cypher stent (RRISC) trial, we analysed the "relocation phenomenon" of QCA-based in-stent minimal luminal diameter (MLD) between post-procedure and follow-up and we correlated QCA-based and IVUS-based restenotic parameters in stented saphenous vein grafts. We expected the presence of MLD relocation for low late loss values, as MLD can "migrate" along the stent if minimal re-narrowing occurs, while we anticipated follow-up MLD to be located close to post-procedural MLD position for higher late loss. QCA-based MLD relocation occurred frequently: the site of MLD shifted from post-procedure to follow-up an "absolute" distance of 5.8 mm [2.5-10.2] and a "relative" value of 29% [10-46]. MLD relocation failed to correlate with in-stent late loss (rho = 0.14 for "absolute" MLD relocation [p = 0.17], and rho=0.03 for "relative" relocation [p = 0.811). Follow-up QCA-based and IVUS-based MLD values well correlated in the overall population (rho = 0.76, p < 0.001), but QCA underestimated MLD on average 0.55 +/- 0.49 mm, and this was mainly evident for lower MLD values. Conversely, the location of QCA-based MLD failed to correlate with the location of IVUS-based MLD (rho = 0.01 for "absolute" values--in mm [p = 0.911, rho = 0.19 for "relative" values--in % [p = 0.111). Overall, the ability of late loss to "predict" IVUS parameters of restenosis (maximum neointimal hyperplasia diameter, neointimal hyperplasia index and maximum neointimal hyperplasia area) was moderate (rho between 0.46 and 0.54 for the 3 IVUS parameters). These findings suggest the need for a critical re-evaluation of angiographic parameters (such as late loss) as endpoints for drug-eluting stent trials and the use of more precise techniques to describe accurately and properly the restenotic process.

In vivo virtual histology intravascular ultrasound correlates of risk factors for sudden coronary death in men: results from the prospective, multi-centre virtual histology intravascular ultrasound registry

We hypothesized a relationship between virtual histology intravascular ultrasound (VH-IVUS) findings and risk factors histopathologically associated with sudden coronary death (SCD) in men: cigarette smoking and an increased total cholesterol-to-high-density lipoprotein cholesterol (HDL-C) ratio (TC/HDL > 5). We assessed volumetric VH-IVUS parameters in a consecutive series of 473 male patients: fibrous, fibro-fatty, dense calcium (DC), necrotic core (NC), and a calculated NC/DC ratio. Patients' age was 61 ± 11 years, with 27% smokers and 69% having a lipid disorder. The NC/DC ratio was the only VH-IVUS parameter related to both TC/HDL ratio (r = 0.18, P= 0.0008) and low-density lipoprotein cholesterol levels (r = 0.17, P= 0.002); had a negative correlation with HDL-C levels (r = -0.11, P= 0.03); and was higher for smokers [median 1.98 (1.35-3.18)] vs. non-smokers [median 1.70 (1.23-2.53), P= 0.006]. An NC/DC value >3 was the threshold that best identified smokers and/or patients presenting TC/HDL >5 (odds ratio 3.0, 95% CI 1.7-4.9, P= 0.0001), and receiver-operator curves showed the superiority of the NC/DC ratio [area under curve (AUC) 0.64, P < 0.0001] over %DC (AUC 0.58, P= 0.006) or %NC (AUC 0.51, P= 0.43) to identify these patients. The ratio of NC to calcification detected by VH-IVUS in diseased coronary segments is related to known risk factors for SCD and, thus, may be associated with a worse prognosis.

Three‐dimensional volumetry and fetal weight measurement

Three‐dimensional volumetry and fetal weight measurement

Newborn society of fetal urology grade 3 hydronephrosis is equivalent to preserved percentage differential function

Purpose In newborn hydronephrosis (HN), the level of differential function (%df) measured by diuretic renography (DR) is used to judge the need for pyeloplasty. As DR testing is complex, we sought to determine if grading the level of HN (Society of Fetal Urology grade, SFU Gr) by a simple ultrasound correlates with percentage differential function (%df) and thereby obviates the need to perform DR. Materials and methods Between 1990 and 2003 our institution prospectively enrolled all cases of fetal HN who showed unilateral newborn SFU Gr HN ≥3. The cases underwent standardized testing. DR was done using the method of Well-Tempered Renography which was then followed by ultrasound (US). The US studies were performed while the hydration induced by DR was in effect. The level of %df was categorized as preserved (≥40%) or reduced (<40%). Cases were excluded if there was an additional urological abnormality (e.g. ureterocele). Results There were 71 cases that met our study criteria. The SFU Gr HN was 3 ( n = 33) or 4 ( n = 38). Kidneys with SFU Gr 3 HN showed preserved %df (33/33,100%) (mean = 50.1 ± 3.6) significantly more often than kidneys with SFU Gr 4 HN (27/38, 71%) (mean = 42.2 ± 13.9) (RR = 1.41, 95% CI (1.15–1.72), p < 0.001). Conclusion In newborns with a history of fetal HN, the postnatal finding of SFU Gr 3 HN uniformly correlates with preserved %df. Standardized hydration prior to US study is done to assure consistency in measurement of the SFU Gr HN. Determining the duration of the relationship between SFU Gr 3 HN and preserved %df will require prospective, longitudinal studies.

UP-03.15: Does detrusor thickness estimated by ultrasound correlate with obstructed urine flowmetry in men with LUTS? A pilot study

UP-03.15: Does detrusor thickness estimated by ultrasound correlate with obstructed urine flowmetry in men with LUTS? A pilot study

Sonographic and MRI evaluation of the plantar plate: a prospective study

The purpose of this study was to establish the accuracy of ultrasound in the examination of the plantar plate by comparing it with MRI, or if available, surgical findings. The lesser metatarsophalangeal joint plantar plates of 40 symptomatic and 40 asymptomatic feet (160 asymptomatic and 160 symptomatic plantar plates) were examined with ultrasound and MRI. Patients treated with surgery were chosen on a clinical basis and provided surgical correlation for the imaging techniques. Symptomatic patients with metatatarsalgia and suspected metatarsophalangeal joint instability were referred by an orthopedic foot specialist; asymptomatic feet were obtained either through examination of the contralateral foot of the symptomatic patients or volunteers. Ultrasound detected 75/160 and 139/160 plantar plates torn in the asymptomatic and symptomatic groups, respectively. MRI detected 56/160 and 142/160 tears in the symptomatic and asymptomatic groups, respectively. The sensitivity of MRI and ultrasound with surgical correlation was calculated to be 87 and 96%, respectively, with poor specificity. Ultrasound correlates moderately with MRI in the evaluation of the plantar plate. Surgical correlations, although limited (n = 10), indicate ultrasound is superior to MRI with more accurate detection of tears.

Ultrasound-based guidance of intensity-modulated radiation therapy

In ultrasound-guided intensity-modulated radiation therapy (IMRT) of prostate cancer, ultrasound imaging ascertains the anatomical position of patients during x-ray therapy delivery. The ultrasound transducers are made of piezoelectric ceramics. The same crystal is used for both ultrasound production and reception. Three-dimensional (3D) ultrasound devices capture and correlate series of 2-dimensional (2D) B-mode images. The transducers are often arranged in a convex array for focusing. Lower frequency reaches greater depth, but results in low resolution. For clear image, some gel is usually applied between the probe and the skin contact surface. For prostate positioning, axial and sagittal scans are performed, and the volume contours from computed tomography (CT) planning are superimposed on the ultrasound images obtained before radiation delivery at the linear accelerator. The planning volumes are then overlaid on the ultrasound images and adjusted until they match. The computer automatically deduces the offset necessary to move the patient so that the treatment area is in the correct location. The couch is translated as needed. The currently available commercial equipment can attain a positional accuracy of 1–2 mm. Commercial manufacturer designs differ in the detection of probe coordinates relative to the isocenter. Some use a position-sensing robotic arm, while others have infrared light-emitting diodes or pattern-recognition software with charge-couple-device cameras. Commissioning includes testing of image quality and positional accuracy. Ultrasound is mainly used in prostate positioning. Data for 7825 daily fractions of 234 prostate patients indicated average 3D inter-fractional displacement of about 7.8 mm. There was no perceivable trend of shift over time. Scatter plots showed slight prevalence toward superior-posterior directions. Uncertainties of ultrasound guidance included tissue inhomogeneities, speckle noise, probe pressure, and inter-observer variation. Some published studies detected improvement in treatment based on gastrointestinal toxicity and the reduction of prostate movement.

We-W31:3 Vasa vasorum neovascularization visualized within the human carotid atherosclerotic plaque: Contrast-enhanced ultrasound imaging and histo-pathologic correlates

We-W31:3 Vasa vasorum neovascularization visualized within the human carotid atherosclerotic plaque: Contrast-enhanced ultrasound imaging and histo-pathologic correlates

Assessment of pelvic floor movement using transabdominal and transperineal ultrasound

The aims of the study were (1) to assess the reliability of transabdominal (TA) and transperineal (TP) ultrasound during a pelvic floor muscle (PFM) contraction and Valsalva manoeuvre and (2) to compare TA ultrasound with TP ultrasound for predicting the direction and magnitude of bladder neck movement in a mixed subject population. A qualified sonographer assessed 120 women using both TA and TP ultrasound. Ten women were tested on two occasions for reliability. The reliability during PFM was excellent for both methods. TP ultrasound was more reliable than TA ultrasound during Valsalva. The percentage agreement between TA and TP ultrasound for assessing the direction of movement was 85% during PFM contraction, 100% during Valsalva. There were significant correlations between the magnitude of the measurements taken using TA and TP ultrasound and significant correlations with PFM strength assessed by digital palpation.

Measurement and correlation of acoustic cavitation with cellular bioeffects

Noninvasive methods to measure and predict ultrasound effects on cells are needed to realize applications of ultrasound-mediated drug delivery to improve chemotherapy, gene therapy and targeted delivery. This study tested the hypothesis that (i) cellular bioeffects of ultrasound correlate with cavitation dose, (ii) broadband noise provides a measure of cavitation dose, and, thus, (iii) cellular bioeffects can be predicted by noninvasively measuring broadband noise. After exposing cell suspensions to ultrasound and measuring intracellular molecular uptake and loss of cell viability (bioeffects), a broad range of bioeffects were achieved by varying frequency, pressure, exposure time, cavitation nucleation site (Optison) concentration, and cell type. As a measure of cavitation activity, broadband noise measurements from acoustic spectra were collected during cell sonication and shown to be larger at elevated pressure and, after a high initial value, sharply decayed to a constant, background value at long exposure times. Combining these results, we found that broadband noise correlated well with molecular uptake and viability over the broad range of experimental conditions used (p-value &amp;lt;0.0001). This indicates that acoustic spectrum analysis provides a unifying parameter to correlate with bioeffects over a wide range of acoustic and experimental conditions. [Work supported by NIH, EKOS, DoEd GAANN Program.]

Ocular ischemic syndrome, central retinal artery obstruction, and branch retinal artery obstruction 1,2

Ocular ischemic syndrome is a condition characterized by visual loss described mainly in males 50 years and older secondary to carotid artery stenosis or occlusion. Loss of vision results from chronic ischemic changes to the anterior and posterior segments of the eye. Pain around the eye has been reported in up to 40% of the patients. Also, these patients may report difficulty adjusting to a darker environment after light exposure. Neovascularization of the iris and retina is common. Associated systemic conditions include arterial hypertension, coronary artery disease, diabetes mellitus, cerebrovascular disease and tobacco use. Digital subtraction angiography can demonstrate carotid artery obstruction in the majority of patients, however less invasive procedures such as contrast enhanced MR angiography in combination with duplex ultrasound correlates with the degree of carotid stenosis. Carotid endarterectomy in addition to management of neovascularization of iris or retina is the treatment of choice, however, the prognosis for visual recovery is still limited. Acute retinal arterial obstruction is a dramatic and usually irreversible painless loss of vision that can involve the central retinal artery or an arterial branch, most commonly secondary to cerebrovascular and cardiovascular disease. Other associated conditions include various hematological, infectious and metabolic abnormalities. In central retinal artery occlusion a common finding includes a cherry red spot in the macula. A careful evaluation of all potential sources of emboli is essential in this condition since there is a strong association with fatal outcome due to cardiovascular disease and stroke. Other etiologies such as coagulopathies, collagen vascular diseases and viral infections have been identified in patients with retinal arterial obstructions. Despite aggressive intervention the visual prognosis of central retinal artery occlusion remains poor.

A limited range of measures of 2-d ultrasound correlate with 3-d mri cerebral volumes in the premature infant at term

Two-dimensional (2-D) cranial ultrasound (US) is the principal method for the detection of cerebral injury in the newborn. The aim of this study was to compare 2-D sonographic methods with more advanced 3-D magnetic resonance imaging (MRI) for assessing brain structure. From July 1998 to November 2000, we conducted a prospective methodological study comparing 2-D cranial sonographic measurements with volumes of cerebrospinal fluid (CSF), white matter, grey matter and total volume of brain obtained using 3-D MRI. The study group comprised 63 infants (33 boys), mean gestational age 28 weeks (range 23 to 33 weeks), with imaging studies within 15 days of term equivalent. The highest correlations were between the occipital horn length and total brain volume (R 2 = 0.30), the subarachnoid space and both CSF volume (R 2 = 0.46) and relative intracranial space occupied by brain tissue (R 2 = 0.48). Only 8 (30%) of the 2-D cranial US measures demonstrated good reproducibility. 2-D sonographic measures are limited in reflecting variations in overall cerebral structure, although certain measures, such as subarachnoid space and occipital lobe measures, may be useful in better defining cerebral parenchymal and CSF volumes. (E-mail: nigel.anderson@cdhb.govt.nz).

Ultrasonic tissue characterization of collagen in lipid-rich plaques in apoE-deficient mice

Mechanical failure of the fibrous cap of a vulnerable atherosclerotic plaque may lead to sudden plaque rupture and thus precipitate arterial thrombosis. Because ultrasound correlates strongly with mechanical features of tissues it might provide information on the stability of fibrous caps. The acoustic properties of the normal vessel wall and plaques, particularly fibrous caps of lipid-rich plaques, were evaluated in the aortic roots of six normal C57BL mice and 12 atherosclerosis-prone apoE-deficient (apoE −/−) mice by scanning acoustic microscopy (SAM). After processing, the attenuation of high-frequency (1.1 GHz) focused ultrasound was measured in unstained tissue sections by SAM followed by quantification of the amount and type of collagen in picrosirius red stained sections by means of polarized light microscopy (PLM). The acoustic and optical images were superimposed and ultrasonic attenuation was measured in different tissue components. Pertinent plaque features, particularly fibrous caps covering lipid-rich pools, were clearly visualized by both SAM and PLM. Collagen appeared green in thin fibrous caps and bright orange in thick caps by PLM. The attenuation of ultrasound was significantly higher in the collagen fibers with orange color compared to those with green color (17.2 versus 6.6×10 3 dB/mm). SAM has shown the possibility to characterize the types of collagen by high frequency intravascular ultrasound in vivo and it might improve our understanding of the vulnerable plaque and its sudden rupture from micro-mechanical point of view.

Echogenicity of substantia nigra determined by transcranial ultrasound correlates with severity of parkinsonian symptoms induced by neuroleptic therapy

Background: Increased echogenicity of the substantia nigra (SN) detected by transcranial sonography is a characteristic ultrasound feature of Parkinson’s disease. This ultrasound feature can also be detected in a subgroup of healthy adults. In recent studies, healthy subjects with this ultrasound feature showed a reduced [ 18F]-Dopa uptake on positron emission tomography (PET), indicating a subclinical alteration of the nigrostriatal system. This study was designed to evaluate whether the severity of neuroleptic side effects is related to the echo-feature of the SN. Methods: In the retrospective part of the study, 93 psychiatric patients with either definite and severe parkinsonism after neuroleptic treatment ( n = 52) or with no or minimal parkinsonian symptoms ( n = 41) were included and underwent transcranial sonography to measure the extension of hyperechogenic areas at the SN. In addition, in the prospective part 11 patients with an acute psychotic episode requiring first-ever neuroleptic treatment underwent ultrasound examination. Subsequently, neuroleptic-induced parkinsonian signs were assessed prospectively. Results: In the retrospective part of the study, patients with severe neuroleptic-induced parkinsonism had more extended echogenic signals at the SN than those with low echogenic SN (U-test; p < .01). The prospective part of the study showed that the severity of parkinsonian symptoms correlated with the echogenicity of the substantia nigra (Spearman’s rank: p < .01). Conclusions: Increased echogenicity of the substantia nigra is associated with impaired function of the nigrostriatal system that can be disclosed by neuroleptic drugs.

The prospects of estimating trabecular bone tissue properties from the combination of ultrasound, dual-energy X-ray absorptiometry, microcomputed tomography, and microfinite element analysis.

Osteoporosis commonly is assessed by bone quantity, using bone mineral density (BMD) measurements from dual-energy X-ray absorptiometry (DXA). However, such a measure gives neither information about the integrity of the trabecular architecture nor about the mechanical properties of the constituting trabeculae. We investigated the feasibility of deriving the elastic modulus of the trabeculae (the tissue modulus) from computer simulation of mechanical testing by microfinite element analysis (muFEA) in combination with measurements of ultrasound speed of sound (SOS) and BMD measurements. This approach was tested on 15 postmortem bovine bone cubes. The apparent elastic modulus of the specimens was estimated from SOS measurements in combination with BMD. Then the trabecular morphology was reconstructed using microcomputed tomography (muCT). From the reconstruction a mesh for muFEA was derived, used to simulate mechanical testing. The tissue modulus was found by correlating the apparent moduli of the specimens as assessed by ultrasound with the ones as determined with muFEA. A mean tissue modulus of 4.5 GPa (SD, 0.69) was found. When adjusting the muFEA-determined elastic moduli of the entire specimens with their calculated tissue modulus, an overall correlation of R2 = 96% with ultrasound-predicted values was obtained. We conclude that the apparent elastic stiffness characteristics as determined from ultrasound correlate linearly with those from muFEA. From both methods in combination, the elastic stiffness of the mineralized tissue can be determined as an estimator for mechanical tissue quality. This method can already be used for biopsy specimens, and potentially could be applicable in vivo as well, when clinical CT or magnetic resonance imaging (MRI) tools with adequate resolution reach the market. In this way, mechanical bone quality could be estimated more accurately in clinical practice.