Sonographic Overview of Usual and Unusual Disorders of the Rectus Femoris Tendon Origins.

Rectus femoris muscle proximal injuries are not rare conditions. The proximal rectus femoris tendinous anatomy is complex and may be affected by traumatic, microtraumatic, or nontraumatic disorders. A good knowledge of the proximal rectus femoris anatomy allows a better understanding of injury and disorder patterns. A new sonographic lateral approach was recently described to assess the indirect head of the proximal rectus femoris, hence allowing for a complete sonographic assessment of the proximal rectus femoris tendons. This article will review sonographic features of direct, indirect, and conjoined rectus femoris tendon disorders.

Ultrasound and magnetic resonance imaging of the peripheral nerves: current techniques, promising directions, and open issues.

High-resolution ultrasound (US) and magnetic resonance (MR) imaging are the two imaging methods of choice for the study of peripheral nerves. The many advances that have been made in recent years, either by US or MR imaging, including diffusion tensor imaging and tractography, offer new perspectives for the assessment of many pathological processes affecting peripheral nerves such as entrapment syndromes, tumors and tumor-like lesions, and traumatic disorders. Most of these improvements have especially increased the spatial resolution of nerve imaging. US and MR imaging are complementary, each having advantages and disadvantages. Tractography is still emerging in the musculoskeletal field, particularly for the analysis of peripheral nerves, but this technique seems promising.

In vivo diffusion tensor imaging and tractography of human thigh muscles in healthy subjects.

OBJECTIVE: The aims of this study were to assess whether similar measurements of mean apparent diffusion coefficient and fractional anisotropy in muscles can be obtained with regions of interest drawn on cross-sectional diffusion tensor images and tractography and to assess whether water diffusivity in human thigh muscles is influenced by muscular compartment, age, and sex. SUBJECTS AND METHODS: Sixteen healthy volunteers (eight women, eight men) participated in this study. The right thigh of each subject was imaged with diffusion tensor imaging, and the mean apparent diffusion coefficient and fractional anisotropy values were calculated for each muscle of the quadriceps femoris and hamstrings. Fiber tracking was performed with a line propagation technique from the regions of interest drawn on cross-sectional diffusion tensor images. RESULTS: The water diffusivity parameters obtained with tractography did not differ significantly from those obtained with diffusion tensor imaging in the three regions of interest evaluated in each muscle. The mean apparent diffusion coefficient of women (1.80 × 10⁻³ mm²/s) was similar to that of men (1.79 × 10⁻³ mm²/s). Women and men had identical fractional anisotropy values (0.26). The fractional anisotropy value in young volunteers (0.27) was similar to that in older subjects (0.26). The hamstrings had a lower mean apparent diffusion coefficient (1.64 × 10⁻³ mm²/s) than the quadriceps femoris (1.91 × 10⁻³ mm²/s), but the quadriceps femoris had a significantly lower fractional anisotropy value (0.25) than the hamstrings (0.28). CONCLUSION: Our study showed that the water diffusivity values (mean apparent diffusion coefficient and fractional anisotropy) of the thigh muscles did not differ significantly with respect to sex or age of the subject. The quadriceps femoris and the hamstrings did have different mean apparent diffusion coefficient and fractional anisotropy values, which may reflect differences in hydration and muscular architecture.

Imaging of the hip in patients with rheumatic disorders.

Hip joint abnormalities are commonly encountered in patients with rheumatic disorders. Although conventional radiography remains the mainstay for diagnosis of joint damage and subsequent follow-up, magnetic resonance imaging and, to a lesser extent, ultrasound have afforded the ability to detect early signs of articular involvement (i.e., synovitis and bone erosions), and to assess disease activity in treated patients. In more advanced stages of rheumatic disorders, magnetic resonance imaging and ultrasound are both useful in assessing paraarticular involvement (i.e., bursitis and synovial cysts).

Ectopic origin of bronchial arteries: assessment with multidetector helical CT angiography.

The purpose of this study was to determine non-invasively the frequency of ectopic bronchial arteries (BA) (i.e., bronchial arteries originating at a level of the descending aorta other than T5-T6 or from any aortic collateral vessel) on multidetector-row CT angiograms (CTA) obtained in patients with hemoptysis. Over a 5-year period (2000-2005), 251 consecutive patients with hemoptysis underwent multidetector-row CT angiography of the thorax. From this population, 37 patients were excluded because of a suboptimal CTA examination (n = 19), the presence of extensive mediastinal disease (n = 15) or severe chest deformation (n = 3) precluding any precise analysis of the bronchial arteries at CTA. Our final study group included 214 patients who underwent a thin-collimated CT angiogram (contrast agent: 300 to 350 mg/ml) on a 4- (n = 56), 16- (n = 119) and 64- (n = 39) detector-row scanner. The site of origin and distribution of bronchial arteries were analyzed on transverse CT scans, maximum intensity projections and volume-rendered images. The site of the ostium of a bronchial artery was coded as orthotopic when the artery originated from the descending aorta between the levels of the fifth and sixth thoracic vertebrae; all other bronchial arteries were considered ectopic. From the studied population, 137 (64%) patients had only orthotopic bronchial arteries, whereas 77 patients (36%) had at least one bronchial artery of ectopic origin. A total of 147 ectopic arteries were depicted, originating as common bronchial trunks (n = 23; 19%) or isolated right or left bronchial arteries (n = 101; 81%). The most frequent sites of origin of the 124 ostiums were the concavity of the aortic arch (92/124; 74%), the subclavian artery (13/124; 10.5%) and the descending aorta (10/124; 8.5%). The isolated ectopic bronchial arteries supplied the ipsilateral lung in all but three cases. Bronchial artery embolization was indicated in 26 patients. On the basis of CTA information, (1) bronchial embolization was attempted in 24 patients; it was technically successful in 21 patients (orthotopic BAs: 6 patients; orthotopic and ectopic BAs: 3 patients; ectopic BAs: 12 patients) and failed in 3 patients due to an instable catheterization of the ectopic BAs; the absence of additional bronchial arterial supply and no abnormalities of nonbronchial systemic arteries at CTA avoided additional arteriograms in these 3 patients; (2) owing to the iatrogenic risk of the embolization procedure of ectopic BAs, the surgical ligation of the abnormal vessels was the favored therapeutic option in 2 patients. This study enabled the depiction of ectopic bronchial arteries in 36% of the studied population, important anatomical information prior to therapeutic decision making.

Coronary imaging quality in routine ECG-gated multidetector CT examinations of the entire thorax: preliminary experience with a 64-slice CT system in 133 patients.

To evaluate image quality in the assessment of the coronary arteries during routine ECG-gated multidetector CT (MDCT) of the chest. One hundred and thirty three patients in sinus rhythm underwent an ECG-gated CT angiographic examination of the entire chest without beta-blockers with a 64-slice CT system. In 127 patients (95%), it was possible to assess the coronary arteries partially or totally; coronary artery imaging failed in six patients (5%), leading to a detailed description of the coronary arteries in 127 patients. Considering ten coronary artery segments per patient, 75% of coronary segments were assessable (948/1270 segments). When the distal segments were excluded from the analysis (i.e., seven coronary segments evaluated per patient), the percentage of assessable segments was 86% (768/889 proximal and mid coronary segments) and reached 93% (474/508) when assessing proximal segments exclusively. The mean number of assessable segments was significantly higher in patients with a heart rate < or =80 bpm (n=95) than in patients with a heart rate >80 bpm (n=38) (p<0.002). Proximal and mid-coronary segments can be adequately assessed during a whole-chest ECG-gated CT angiographic examination without administration of beta-blockers in patients with a heart rate below 80 bpm.

Integrated cardio-thoracic imaging with ECG-Gated 64-slice multidetector-row CT: initial findings in 133 patients.

The purpose of this study was to investigate the possibility of assessing the underlying respiratory disease as well as cardiac function during ECG-gated CT angiography of the chest with 64-slice multidetector-row CT (MDCT). One hundred thirty-three consecutive patients in sinus rhythm with known or suspected ventricular dysfunction underwent an ECG-gated CT angiographic examination of the chest without beta-blockers using the following parameters: (1) collimation: 32 x 0.6 mm with z-flying focal spot for the acquisition of 64 overlapping 0.6-mm slices (Sensation 64; Siemens); rotation time: 0.33 s; pitch: 0.3; 120 kV; 200 mAs; ECG-controlled dose modulation (ECG-pulsing) and (2) 120 ml of a 35% contrast agent. Data were reconstructed: (1) to evaluate the underlying respiratory disease (1-mm thick lung and mediastinal scans reconstructed at 55% of the R-R interval; i.e., "morphologic scans") and (2) to determine right (RVEF) and left (LVEF) ventricular ejection fractions (short-axis systolic and diastolic images; Argus software; i.e., "functional scans"). The mean heart rate was 73 bpm (range: 42-120) and the mean scan time was 18.11 +/- 2.67 s (range: 10-27). A total of 123 examinations (92%) had both lung and mediastinal images rated as diagnostic scans, whereas 10 examinations (8%) had non-diagnostic images altered by the presence of respiratory-motion artifacts (n = 4) or cyclic artifacts related to the use of a pitch value of 0.3 in patients with a very low heart rate during data acquisition (n = 6). Assessment of right and left ventricular function was achievable in 124 patients (93%, 95% CI: 88-97%). For these 124 examinations, the mean RVEF was 46.10% (+/- 9.5; range: 20-72) and the mean LVEF was 58.23% (+/- 10.88; range: 20-83). In the remaining nine patients, an imprecise segmentation of the right and left ventricular cavities was considered as a limiting factor for precise calculation of end-systolic and end-diastolic ventricular volumes. The mean (+/- SD) DLP value of the examinations was 279.86 (+/- 117.50) mGy.cm. Assessment of underlying respiratory disease and cardiac function from the same data set was achievable in 92% of the patients with ECG-gated 64-slice MDCT.

Multi-detector row CT of hemoptysis.

Hemoptysis is symptomatic of a potentially life-threatening condition and warrants urgent and comprehensive evaluation of the lung parenchyma, airways, and thoracic vasculature. Multi-detector row computed tomographic (CT) angiography is a very useful noninvasive imaging modality for initial assessment of hemoptysis. The combined use of thin-section axial scans and more complex reformatted images allows clear depiction of the origins and trajectories of abnormally dilated systemic arteries that may be the source of hemorrhage and that may require embolization. Conditions such as bronchiectasis, chronic bronchitis, lung malignancy, tuberculosis, and chronic fungal infection are some of the most common underlying causes of hemoptysis and are easily detected with CT. "Cryptogenic" hemoptysis is common among smokers and warrants subsequent follow-up imaging to exclude possible underlying malignancy. The bronchial arteries are the source of bleeding in most cases of hemoptysis. Contributions from the non-bronchial systemic arterial system represent an important cause of recurrent hemoptysis following apparently successful bronchial artery embolization. Vascular anomalies such as pulmonary arteriovenous malformations and bronchial artery aneurysms are other important causes of hemoptysis. Multi-detector row CT angiography permits noninvasive, rapid, and accurate assessment of the cause and consequences of hemorrhage into the airways and helps guide subsequent management.

When, why, and how to examine the heart during thoracic CT: Part 1, basic principles.

OBJECTIVE: MDCT systems with fast scanning capabilities can acquire images of the thorax with reduced cardiac motion artifacts, enabling improved evaluation of the heart and surrounding structures in the course of routine thoracic CT. This article describes the principles of including an evaluation of the heart in the course of a chest CT examination in terms of both examination technique and image interpretation. In addition, both the normal appearances and some of the most common abnormal appearances of the cardiac structures will be described. CONCLUSION: Details concerning the cardiac structures can inform interpretation of thoracic CT studies and can influence the patient's clinical management. Both unenhanced and contrast-enhanced scans can detect significant cardiac disorders that may otherwise go undetected. In certain situations, a CT examination of the entire chest, complemented by cardiac gating, can provide a more dedicated analysis of the heart and coronary arteries, providing both morphologic and functional information.

When, why, and how to examine the heart during thoracic CT: Part 2, clinical applications.

OBJECTIVE: CT examination of the thorax is often requested for the investigation of disorders that may have an important underlying cardiac cause or association that is not clinically obvious. Conditions such as idiopathic and acquired cardiomyopathy, ischemic heart disease, and valvular dysfunction may underlie symptoms such as dyspnea, chest pain, and hemoptysis that prompt the request for CT of the thorax. Other conditions such as pulmonary thromboembolic disease, chronic obstructive airways disease, pectus excavatum, sleep apnea, and many intrathoracic malignancies may have an important effect on cardiac structure and function. Patients undergoing thoracic surgery may have unsuspected coronary artery disease that can be detected in the course of preoperative evaluation by CT; similarly, postoperative complications often have a cardiogenic basis. CONCLUSION: Examination of the heart in the course of CT of the chest often can provide important and clinically relevant information that is not otherwise easily available.

Spinal arachnoid cyst related to a nonaneurysmal perimesencephalic subarachnoid hemorrhage: case report.

OBJECTIVE AND IMPORTANCE: We report the first case of a delayed symptomatic spinal arachnoid cyst related to a nonaneurysmal perimesencephalic hemorrhage. We review the literature concerning posthemorrhagic spinal arachnoid cysts. CLINICAL PRESENTATION: A 64-year-old woman presented with progressive spinal cord compression symptoms 10 months after a nonaneurysmal perimesencephalic hemorrhage. Magnetic resonance imaging of the spine disclosed a dorsal and intradural cystic lesion producing posterior spinal cord compression. INTERVENTION: A thoracic laminectomy allowed complete resection of the cyst. Surgical and histological findings disclosed an intradural arachnoid cyst. On postoperative follow-up, spinal magnetic resonance imaging confirmed satisfactory decompression of the spinal cord. Because of extensive arachnoiditis, the patient experienced only partial recovery from neurological deficits. CONCLUSION: This extremely rare complication should be kept in mind when delayed lower-limb neurological deficits appear after subarachnoid hemorrhage, even in a perimesencephalic form.

MR imaging in the diagnosis of desmoplastic infantile tumor: retrospective study of six cases.

BACKGROUND AND PURPOSE: Desmoplastic infantile tumors (DITs) are rare supratentorial tumors of infancy with a favorable prognosis. Radiologic and histologic features of DIT are misleading, and DIT may be misinterpreted as a malignant lesion. We have studied the usefulness of MR imaging in the diagnosis of these tumors. METHODS: Between 1995 and 2002, six DITs were diagnosed in young children at our institution. Neuroimaging, age at diagnosis, sex, clinical presentation, symptoms duration, follow-up, and development were studied retrospectively. Contrast-enhanced CT and MR images were available. MR study included T1-, T2-, and postgadolinium T1-weighted sequences in the axial, sagittal, and coronal planes. RESULTS: These tumors were massive and predominantly cystic, with preferential frontal and parietal involvement. Typically, a DIT appears as a hypointense cystic mass with an isointense peripheral solid component on T1-weighted MR images. The peripheral solid component enhances after gadolinium administration. On T2-weighted MR images, the cystic component is hyperintense and the solid portion isointense or heterogeneous. The cystic portion is usually located deep inside the lesion, whereas its solid portion is peripheral. Meningeal enhancement and thickening adjacent to the solid portion of the tumor, calcifications, bone abnormalities adjacent to the tumor consisting of thinning and deformation were noted in 50% of our cases. Edema was usually absent or moderate. Median follow-up was 32 months, and no recurrence was noted except for one atypical case with incomplete excision, which led to the patient's death. CONCLUSION: Despite their malignant appearance, MR imaging features of DIT may help in the diagnosis and obviate unnecessary chemotherapy or radiation therapy.