Sciatic nerve: sonographic evaluation and anatomic-pathologic considerations

Sonographic analysis of the sciatic nerve was performed in vitro (anatomic specimen), in vivo (healthy volunteers), and in 16 patients with suspected peripheral sciatic nerve lesions. The ultrasound (US) examinations were performed with standard and high-resolution US equipment with linear-array configuration. The normal nerve displayed an echogenic fibrillar texture with round cross-sectional structure on both in vitro and in vivo sonograms. Satisfactory delineation of the nerve was obtainable in all cases. Nerve displacement was the main sonographic finding in cases of extrinsic compression. The lesion displayed variable echotexture, ranging from hypoechogenicity or mixed echogenicity in hematomata to hyperechogenicity in cases of fibrosis. Primary nerve tumors (neurofibroma) or infiltrating tumors (desmoid) caused clear disruption of the nerve structure. Use of sonography enabled assessment of the continuity of the nerve margins with the interposed graft in a case of reconstructive surgery. The potential to image sciatic nerve lesions noninvasively may have an important impact on diagnosis, treatment, and prognosis in symptomatic patients.     

彩色多普勒超声在剖宫产切口处妊娠诊治中的价值

目的:探讨彩色多普勒超声在剖宫产术后子宫前壁峡部切口处早期妊娠(cesarean scar pregnancy,CSP)诊断和治疗中的应用价值。方法:回顾性分析12例CSP的超声声像图特征,包括病灶周边的血流分布、RI等。12例采用全身药物治疗后配合超声引导下绒毛植入区注射甲氨蝶呤(MTX)和米非司酮或从孕囊内抽吸囊液再注射MTX,其中4例在超声引导下行清宫术,治疗后对子宫前壁下段切口处的血流分布和RI等进行对比分析。结果:12例中,4例经超声引导下清宫后病理证实,8例经超声和临床明确诊断;9例超声显示为单纯孕囊型,3例为不均质团块型。12例治疗前后病灶长径、宽径差异均无统计学意义(P均0.05),子宫前壁下段肌层厚度增加(P0.000 1),病灶回声减低、周边及内部血流信号减少,RI升高(P0.000 1)。结论:超声是诊断CSP的首选方法,保守治疗者可在超声引导下局部注射MTX。超声同时可指导选择清宫治疗时机,评价治疗效果。     

Peroneal nerve palsy associated with knee luxation: evaluation by sonography--initial experiences

OBJECTIVE: Traumatic knee dislocation needs immediate surgical repair to restore joint function. A concomitant traction injury of the peroneal nerve is reported to exist in up to 25% of cases and is often overlooked initially. In patients with major nerve lesions, immediate surgical nerve repair might be necessary to avoid irreversible loss of neural function. In the present study, we tried to evaluate whether sonography is a valuable tool for identification of nerve pathology that warrants surgical intervention. SUBJECTS AND METHODS: In this prospective study, both peroneal nerves in nine patients with one-sided peroneal nerve palsy after closed knee luxation and the peroneal nerves of 11 healthy volunteers were investigated with sonography. Using statistical analysis, we tried to define the comparability and significance of the findings. RESULTS: The mean cross-sectional area of healthy peroneal nerves in the genicular region was 0.18 cm2 (SD, 0.07 cm2). Impaired nerves were significantly discerned because of their increased cross-sectional area at the level of the injury (mean cross-sectional area, 0.7 cm2; SD, 0.46 cm2; p < 0.05). Identification of caliber changes and depiction of at least one nerve stump were found to be the most specific criteria for the definition of a major neural lesion. The ability of sonography to provide additional information about surrounding soft-tissue impairment (scar tissue and hematoma formation) proved helpful. CONCLUSION: Sonography allows radiologists to visualize neural and extraneural pathology and to define the exact level and extent of lesions. Thus, it may be a valuable adjunct in the decision of whether surgical intervention is necessary.     

Hepatocellular carcinoma: sonographic and histologic correlation

Sonographic and histologic correlation was studied in 20 cases with a combined total of 23 resected lesions of hepatocellular carcinoma. All cases were examined by sonography within 1 week before surgery. Tumor sonograms were classified as hypoechoic, complex, or hyperechoic on the basis of the difference in echogenicity between the lesion and the surrounding liver parenchyma. Fourteen excised pathologic specimens were examined after surgery by a fixed-position sectional sonographic technique that permitted detailed comparison of the sonograms with the histologic findings. Each of the three types of lesion classified by echo pattern exhibited specific histopathologic characteristics. The hypoechoic lesion corresponded to a solid tumor without necrosis; the complex lesion corresponded to a tumor with partial necrosis; and the hyperechoic lesion was represented histopathologically by two distinct types of tumor, one with fatty metamorphosis and the other with marked sinusoidal dilatation. Fixed-position sectional sonography is a useful technique for comparing histologic and sonographic findings in a given tissue section and it contributes to the investigation of tissue characterization by sonography.     

Sonography of postexcision specimens of nonpalpable breast lesions: value, limitations, and description of a method

OBJECTIVE: The objective of our study was to retrospectively review our experience regarding the value of sonography in identifying a nonpalpable mass within a surgically excised specimen and in assessing the surgical margins in cases of malignancy. MATERIALS AND METHODS: One hundred four lumpectomies were performed in 99 consecutive patients with 131 nonpalpable breast lesions after sonographically guided needle localization. All 104 surgical specimens were scanned on sonography, and 86 specimen radiographs were obtained. Visualization of the lesion on sonography was compared with specimen radiographs and histologic findings. Sonographic margin status was classified as negative (shortest distance between tumor and specimen margin, > 0.2 cm) or positive (shortest distance between tumor and specimen margin, 0.2 cm) and was compared with pathology results. RESULTS: Specimen sonography showed 95.4% (125/131) of the excised abnormalities; nonfatty background and a lesion size of greater than 0.5 cm contributed significantly to the success of specimen sonography. Four of six lesions missed on sonography were identified on specimen radiography. Among 81 malignant specimens, sonography identified 38 specimens with positive margins and 43 with negative margins. Pathologic examination revealed eight false-positive and 10 false-negative results (21% false-positive rate and 23.2% false-negative rate). CONCLUSION: Specimen sonography is an effective procedure for identifying the presence of the lesion within the specimen; however, it is of limited value in cases of small hypoechoic lesions against a fatty background. Assessment of margins is limited by both false-positive and false-negative results.     

Sonography of the postoperative shoulder

Fifty-three patients with 60 symptomatic shoulders underwent shoulder sonography for recurrent postoperative symptoms after either acromioplasty (10 shoulders) or repair of a full-thickness rotator cuff tear in addition to acromioplasty (50 shoulders). Because surgery distorts landmarks, an understanding of the surgical procedures and their characteristic sonographic appearances is essential. After acromioplasty, the characteristic sharp margination or the acromion was replaced by a less distinct, irregular surface. After repair of a cuff tear, characteristic sonographic appearances included visualization of a reimplantation trough and loss of the echogenic subdeltoid bursa. When the cuff was intact after surgery, echogenicity was abnormal in all cases (17 shoulders). Sonography accurately diagnosed recurrent cuff tears in all 26 shoulders in which surgical proof was available and confirmed an intact cuff in 10 of 11 cases. In one shoulder, a cuff hematoma was incorrectly interpreted as a full-thickness tear. These findings suggest that sonography is an effective procedure for evaluating a postoperative patient with recurrent shoulder symptoms.     

Bildgebende Diagnostik von Nervenkompressionssyndromen

Compression-induced neuropathy of peripheral nerves can cause severe pain of the foot and ankle. Early diagnosis is important to institute prompt treatment and to minimize potential injury. Although clinical examination combined with electrophysiological studies remain the cornerstone of the diagnostic work-up, in certain cases, imaging may provide key information with regard to the exact anatomic location of the lesion or aid in narrowing the differential diagnosis. In other patients with peripheral neuropathies of the foot and ankle, imaging may establish the etiology of the condition and provide information crucial for management and/or surgical planning. MR imaging and ultrasound provide direct visualization of the nerve and surrounding abnormalities. Bony abnormalities contributing to nerve compression are best assessed by radiographs and CT. Knowledge of the anatomy, the etiology, typical clinical findings, and imaging features of peripheral neuropathies affecting the peripheral nerves of the foot and ankle will allow for a more confident diagnosis.     

Tumor vascularity of breast lesions: potentials and limits of contrast-enhanced Doppler sonography

OBJECTIVE: We investigated improving the evaluation of benignity in breast lesions using Doppler sonography with galactose palmitic acid-coated microbubbles. SUBJECTS AND METHODS: In 77 patients with 84 breast tumors scheduled for surgical tumor removal, color-coded duplex sonography was performed before and after administration of Levovist. Of the 77 patients, 25 with 28 lesions had been treated for prior breast carcinoma. The parameters investigated were the following: degree of enhancement, number of tumor vessels, time to maximum enhancement, and the pattern of vascular morphology and course. RESULTS: Findings in malignant tumors (n = 53) showed a greater number of vessels and a faster stronger enhancement after Levovist administration, whereas a definite partial overlap with results from benign tumors (n = 31) was found. The best distinction was produced by vascular morphology and course, with a sensitivity of 90% and a specificity of 81 %. In 23 of the 25 patients who previously underwent surgery, a clear distinction was possible between a postoperative scar (n = 11) and a tumor recurrence (n = 17). CONCLUSION: Although administration of the contrast agent clearly improved evaluation of benign features on Doppler sonography, absolute certainty cannot be achieved. The feasibility of making an otherwise difficult distinction between a scar and tumor recurrence on sonography and mammography appears to be promising, but further studies are necessary.     

Traumatic neuropathies: spectrum of imaging findings and postoperative assessment

Traumatic injury to peripheral nerves is a significant cause of morbidity and disability. Until reinnervation occurs, electrodiagnostic studies cannot differentiate severe axonotmetic lesions (Sunderland class 4) from complete nerve transection or neurotmesis (Sunderland class 5). This limitation is relevant clinically because in cases of neurotmesis an improved outcome may be achieved with an early surgical repair (within 1 week after trauma). High-resolution ultrasound (US) is an efficient modality to visualize injured nerves and is becoming increasingly important among radiologists and surgeons. Magnetic resonance (MR) imaging is complementary to high-resolution US, especially in evaluating deep-seated and proximal nerve segments. This article describes the imaging features of traumatic peripheral nerve lesions. The role of diagnostic imaging in stretching injuries, contusion trauma, penetrating wounds, and after surgery is discussed. A multimodality diagnostic approach including physical examination, electrophysiology, and US and MR imaging allows an accurate evaluation of most peripheral nerves. Imaging assessment of peripheral nerves trauma is useful for the diagnosis, follow-up, and postoperative evaluation.     

周围神经源性良性肿瘤的超声特性

目的通过分析周围神经源性良性肿瘤的超声特性,评价超声在周围神经源性良性肿瘤中的诊断作用。方法采用回顾性调查方法收集2000—2011年我院收治的有完整临床资料的良性周围神经肿瘤65例患者的术前超声检查、手术图片及病理检查结果,其中58例肿瘤患者同时包含彩色多普勒超声检查结果,由2位有丰富临床经验的超声影像医师对患者的术前超声图像进行回顾分析,评估肿瘤超声特性包括肿瘤的形状、大小、边界、包膜、内部回声特性、后方回声情况与周围神经的关系以及血流情况。结果本组65例良性周围神经源性肿瘤70处病变的超声检查结果显示42处病变(60%)为内部回声均匀的实质性低回声结构;28处病变(40%)为回声不均的低回声结构,其中18处(26%)病变为低回声结构内部可见高回声区,10处(14%)病变为低回声结构内部可见液性暗区;36处病变与知名周围神经相连。58例肿瘤彩色多普勒超声检查显示24例肿瘤(41%)有丰富血流信号,22例肿瘤(38%)有少量血流信号,12例(21%)肿瘤无血流信号。65例患者70处病变均行手术切除,术中见54处病变来源于知名的周围神经,16处病变位于肌肉内,无知名神经纤维连结。超声检查显示病变与神经相连的阳性率为67%(36/54)。65例肿瘤手术切除后病理检查结果显示,62例肿瘤为神经鞘膜瘤,2例为神经纤维瘤,1例为神经纤维瘤病。结论超声检查能提供良性神经源性肿瘤较详细的形态、内部结构、边界、包膜以及肿瘤与周围组织的关系的信息,还能显示肿瘤与周围神经的联系以及血流情况等,检查方便易行,检查费用低廉,患者易于接受。     

Posterior fontanelle sonography: an acoustic window into the neonatal brain

BACKGROUND AND PURPOSE: Sonographic brain studies are classically performed through the anterior fontanelle, but visualization of posterior supratentorial and infratentorial structures is poor with this approach. Posterior fontanelle sonography is recommended for better assessment of these structures. Our purpose was 1) to determine whether sonography of the brain through the posterior fontanelle (PF) improves visualization of brain lesions when added to the routine anterior fontanelle (AF) approach and 2) to describe standardized PF coronal and sagittal sections. METHODS: In this prospective study (conducted from February 1999 to January 2001), PF sonography was added to AF sonography in 165 consecutive premature neonates with a birth weight of < 2000 g. Sonograms were recorded in digital format for re-evaluation at the end of the study. Lesions were grouped as congenital, infectious, hemorrhagic, or hypoxic-ischemic. The chi2 test for paired data and the kappa coefficient were used to compare diagnoses with AF alone and diagnoses with AF plus PF. RESULTS: PF sonography was performed in 164 of 165 patients. Results were normal in 86 and abnormal in 78. The single posterior fossa malformation detected in this series was best delineated with the PF approach. PF sonography increased the diagnostic rate of grade II hemorrhage by 32%. Cerebellar hemorrhage (two patients) and cerebellar abscesses (one patient) were diagnosed by using the PF approach. PF sonography did not contribute to the diagnosis of periventricular leukomalacia. CONCLUSION: Study of the neonatal brain with the addition of PF sonography afforded greater accuracy in detecting intraventricular hemorrhage compared with AF sonography alone, especially when the ventricle was not dilated. The PF approach better defines posterior fossa malformations.     

Hepatic infarcts: new observations by CT and sonography

Until recently hepatic infarcts were rarely diagnosed before autopsy and were nearly always fatal. Four cases of hepatic infarcts, three of them nonfatal, were diagnosed and followed by CT (three cases), sonography (two cases), arteriography (two cases), and sulfur colloid liver-spleen scan (one case). In three patients with multiple subsegmental hepatic infarcts, most of the lesions were round or oval and centrally located. Only a minority of the lesions were wedge-shaped and peripheral. The early lesion appears hypoechoic on sonography, and CT shows a poorly demarcated low-density region. Later, lesions become confluent with more distinct margins. Bile lakes are a late sequela of large infarcts. Gas formation within sterile infarcts is newly described in two cases. Hepatic infarcts have a variable appearance on CT and sonography and are not reliably distinguished from other lesions such as abscess or necrotic neoplasm.     

Diagnostic accuracy of phase-inversion tissue harmonic imaging versus fundamental B-mode sonography in the evaluation of focal lesions of the kidney

OBJECTIVE: We compared phase-inversion tissue harmonic imaging with fundamental B-mode sonography in the evaluation of focal lesions of the kidney. SUBJECTS AND METHODS: For our prospective study, 114 patients underwent sonography of the kidneys in both modes, fundamental B-mode sonography and phase-inversion tissue harmonic imaging, in a randomly chosen scanning order. Imaging parameters were standardized. Sonographic diagnoses were made under real-time conditions by the examining radiologist. All sonographic diagnoses were compared with a diagnostic reference modality: contrast-enhanced CT, contrast-enhanced MR imaging, or histopathology. Three radiologists different from the examiners evaluated overall image quality, lesion conspicuity, and fluid-solid differentiation for both modalities using hard-copy images. RESULTS: In 70 patients, fundamental B-mode sonography as the first technique depicted 73 of 111 lesions 10 mm or larger and enabled 71 lesions to be correctly characterized (sensitivity, 65.8%; accuracy, 64.0%). As the first mode, phase-inversion tissue harmonic imaging depicted 57 of 65 focal lesions and enabled 54 lesions to be accurately classified in 44 patients (sensitivity, 87.7%; accuracy, 83.1%). The differences in sensitivity and accuracy were statistically significant (95% confidence interval). For overall image quality, lesion conspicuity, and fluid-solid differentiation phase-inversion harmonic imaging was superior to fundamental B-mode sonography (p < 0.0001). CONCLUSION: Phase-inversion tissue harmonic imaging is superior to fundamental B-mode sonography in the sonography of focal kidney lesions because phase-inversion tissue harmonic imaging has better overall image quality, lesion conspicuity, and fluid-solid differentiation. In six cases, phase-inversion tissue harmonic imaging added crucial diagnostic information that changed patient management.     

Sonography and electrodiagnosis in carpal tunnel syndrome diagnosis, an analysis of the literature

We present a review of the international literature concerning sonography for the diagnosis of carpal tunnel syndrome (CTS). Analysis of the results and comparison with electrodiagnostic data provide a sensible albeit personal view on the relevance of sonography and whether it competes or is complementary to electrodiagnosis (EDX). Although EDX is considered as the gold standard for CTS diagnosis, one author chose surgical results to define CTS. The normal and threshold mean values for sonography are particularly variable from one study to another. The standard deviation (S.D.), when compared to mean values, makes normal and abnormal data overlap considerably and produces many false negatives when the specificity is high, and many false positives when the sensitivity is high. In fact, sonography is non-interpretable in only 10 to 15% of the population, and it affirms the median nerve lesion at the wrist in 55% of cases when EDX does it in more than 90% with common tests. Further more the specificity of sonography leads to a false positive diagnosis in 1 case out of 5 versus 1 out of 40 with EDX. The main conclusion is that there is no competition but rather a complementarity between sonography and EDX: sonography is certainly an efficient imaging technique but cannot replace proper EDX performed for upper limb paresthesiae. Namely, sonography can answer only one out of the 8 questions a complete EDX answer: Are sonographic images compatible with a median nerve lesion at the wrist? The answer to this solely question can be obtain with a partial EDX using a single conduction test (motor or sensitive), then duration and cost will be comparable to sonography but will be both more sensitive and specific. Finally, one must kept in mind that the final aim of all examinations in CTS is to determine the cause(s) of upper limb paresthesiae, not simply if there is a median nerve lesion at wrist or not.     

MR imaging of the postoperative lumbar spine: assessment with gadopentetate dimeglumine

This study defines the accuracy of gadopentetate-dimeglumine-enhanced MR imaging in patients with failed back surgery syndrome by comparing the imaging studies with surgical findings in a large patient population. From June 1988 to March 1989, 193 postoperative patients had MR imaging of the lumbar spine both with and without contrast administration. Of this group, 27 had repeat surgery at 31 levels: these patients comprise the study group. Postcontrast MR diagnoses were as follows: scar only (n = 4), disk only (n = 13), scar and disk (n = 9), and no aberrant epidural tissue (n = 5). Surgical diagnoses differed from the MR diagnoses in two patients at two levels. In one patient, disk was diagnosed on MR while osteophyte was present at surgery. In the other patient, scar only was diagnosed by MR but disk and scar were present at surgery. These data, when combined with the authors' previous experience, give pre- and postcontrast MR a 96% accuracy in differentiating scar from disk in 44 patients at 50 reoperated levels. For patients 6 or more weeks past surgery, sagittal and axial T1-weighted MR imaging before and after administration of gadopentetate dimeglumine is an effective method of evaluating the postoperative lumbar spine.     

MR imaging of the postoperative lumbar spine: assessment with gadopentetate dimeglumine

This study defines the accuracy of gadopentetate-dimeglumine-enhanced MR imaging in patients with failed back surgery syndrome by comparing the imaging studies with surgical findings in a large patient population. From June 1988 to March 1989, 193 postoperative patients had MR imaging of the lumbar spine both with and without contrast administration. Of this group, 27 had repeat surgery at 31 levels: these patients comprise the study group. Postcontrast MR diagnoses were as follows: scar only (n = 4), disk only (n = 13), scar and disk (n = 9), and no aberrant epidural tissue (n = 5). Surgical diagnoses differed from the MR diagnoses in two patients at two levels. In one patient, disk was diagnosed on MR while osteophyte was present at surgery. In the other patient, scar only was diagnosed by MR but disk and scar were present at surgery. These data, when combined with the authors' previous experience, give pre- and postcontrast MR a 96% accuracy in differentiating scar from disk in 44 patients at 50 reoperated levels. For patients 6 or more weeks past surgery, sagittal and axial T1-weighted MR imaging before and after administration of gadopentetate dimeglumine is an effective method of evaluating the postoperative lumbar spine.     

Immediate postoperative mammogram for failed surgical excision of breast lesions

In a series of 200 consecutive preoperative needle localizations of non-palpable breast lesions, 128 lesions (64%) were calcified and 72 lesions (36%) were noncalcified on preoperative mammograms. Radiographs of the surgical specimen failed to confirm excision of 11 lesions (5.5%), seven calcified and four noncalcified. These 11 patients were taken directly from the surgical suite to the radiology suite, where an immediate postoperative mammogram was obtained. In five patients (2.5%), immediate postoperative mammograms showed surgical failure with the lesion still present. In six patients (3.0%), immediate postoperative mammograms showed that the lesion had been removed, even though the lesion had not been identified on surgical-specimen radiographs. No errors occurred in the interpretation of immediate postoperative mammograms, a fact corroborated by examination of surgical specimens obtained at repeat surgery in three patients and identification of skin calcifications in two patients, and with follow-up mammograms in six patients. Whenever a discrepancy between preoperative localization radiographs and surgical-specimen radiographs exists, the authors suggest immediate postoperative mammography to improve the diagnostic process.     

MSCT多期增强扫描对肝脏局灶性结节增生的诊断价值

目的:探讨MSCT多期增强扫描对肝脏局灶性结节增生(focal nodular hyperplasia,FNH)的诊断价值。方法:回顾性分析经手术及穿刺活检病理证实的9例FNH患者10个病灶的MSCT多期增强扫描表现。结果:9例中8例为单发病灶,1例多发。平扫9个呈低或稍低密度,1个等密度。平扫3个病灶见中央瘢痕;多期增强扫描7个病灶见中央瘢痕,动脉期及门脉期瘢痕均未见强化,延迟期5个见中央瘢痕强化。增强扫描动脉期除中央瘢痕外,8个FNH病灶明显均匀强化,2个中等均匀强化;门脉期病灶密度下降,但均略高于或等于正常肝实质;延迟期病灶密度等于或略低于肝实质。动脉期4个病灶中心或周边见增粗的供血动脉,其中1个为肝动脉分支直接进入病灶中心,1个的供血动脉自病灶中心沿纤维间隔向周边呈放射状分布,另2个周边见供血动脉。结论:MSCT多期扫描可反映病灶的血供特点和病理学特征,对FNH具有重要的诊断及鉴别诊断价值。     

Sonography of the wrist and the hand

Sonographic examination of the hand requires high-frequency linear transducers. As the relevant structures are located very close to the surface, water stand-off pads are mandatory. Owing to the high sensitivity of sonography in the detection of fluid, exudative synovitis, tenosynovitis and ganglia can be easily diagnosed. Sonographic information on muscle atrophy and alterations of the shape and echogenicity of the median nerve in patients with carpal tunnel syndrome may be useful in evaluating the extent of disease. Further indications for the sonographic examination of the hand include suspected tumors, foreign bodies and synovial proliferation. Osseous destruction can be visualized in patients with rheumatoid disease, but the precise extent is hard to determine.     

Sonographic assessment of osteochondritis dissecans of the humeral capitellum

OBJECTIVE: The purpose of this study was to determine the efficacy of sonography for revealing osteochondritis dissecans of the humeral capitellum. SUBJECTS AND METHODS: Twenty-seven patients with capitellar osteochondritis dissecans (27 males; range, 11-20 years; mean age, 14 years) underwent radiography and sonography performed with a 7.5-MHz mechanical sector probe. Lesions were assessed as stable or unstable. The sonographic assessment was compared with radiographic assessment in 27 patients, MR assessment obtained in 10, and surgical findings in 15. RESULTS: Sonographic assessment agreed with radiographic assessment in 23 of the 27 patients, MR assessment in nine of the 10, and surgical findings in 14 of the 15. Sonography revealed that two lesions, which had been underestimated on radiography, were unstable. CONCLUSION: Sonography facilitates the assessment of capitellar lesions so that treatment can be optimized.