Imaging of malignant lymphoma of muscular sites

Seventeen cases of muscular lymphoma are reported (5 primary non-Hodgkin lymphoma, 11 secondary NHL, 1 secondary Hodgkin's disease). The psoas or gluteus muscle was involved in 10 cases, and the lower limb was affected in the remaining 7 cases. Nine cases of muscular extension of bone NHL are also reported. On sonograms these lesions were always large and less echogenic than adjacent structures, with no signs of necrosis before treatment. US and CT patterns were comparable for both primary and secondary lesions, regardless of the type of lymphoma or whether or not there was any previous bone lesion. Associated lymphomatous lesions were observed in 14 cases. On angiograms, muscular lymphomatous involvement presented a hypovascular pattern. While ultrasonography is an excellent monitoring technique for soft tissue lymphomas (specially for the lower limbs), a major contribution of CT is the detection and the follow-up of deep or thoracic wall lesions.     

Staging of rectal cancer after polypectomy: usefulness of endorectal US

PURPOSE: To determine the usefulness of endorectal ultrasonography (US) in staging rectal cancer discovered at polypectomy. MATERIALS AND METHODS: Before surgical resection, endorectal US was performed in 18 consecutive patients with adenocarcinoma discovered in polypectomy specimens. A rotating 7-10-MHz endoprobe with an inflatable balloon was used in all cases. The precise depth of penetration (T stage) was determined with endorectal US and correlated with the histopathologic findings. RESULTS: For detection of residual tumor after polypectomy, endorectal US had a sensitivity of 100%, specificity of 44%, positive predictive value of 64%, and negative predictive value of 100%. Although the precise T stage was correctly predicted with endorectal US in only eight patients (44%), endorectal US was able to demonstrate whether the tumor was limited to the bowel wall in 16 patients (89%). CONCLUSION: Endorectal US is an accurate technique for localizing tumors to or beyond the rectal wall in patients who have undergone diagnostic polypectomy. Although inaccuracies in determining the specific T stage may occur, endorectal US facilitates surgical planning in the vast majority of patients and should therefore remain the local staging technique of choice in this specific patient population.     

体表超声对进展期贲门癌的诊断价值

目的:探讨经体表超声判断贲门癌沿食管向上侵犯的长度及浸润深度的准确性,及其在外科治疗方案选择中的价值.方法:经体表超声对40例贲门癌患者探查,重点观察肿瘤侵犯食管长度及是否侵犯浆膜,并与术后病理结果对照.结果:超声诊断肿瘤侵犯外膜的灵敏性为71.0%,特异性为77.8%,总的符合率为72.5%.4例食管没有受到侵犯的患者诊断符合率为100%,36例食管侵犯的患者超声诊断的符合率为78%(28/36).贲门癌沿食管向上侵犯长度超声测量误差为(0.77±0.46) cm.结论:体表超声在贲门癌诊断中发挥重要作用,尤其是能够对受侵犯食管的长度及浸润深度作出判断,对外科治疗方案的选择有着很高的参考价值.     

Tumor invasion of the chest wall and mediastinum in lung cancer: evaluation with pneumothorax CT

For preoperative evaluation of chest wall and mediastinal invasion by lung cancer, computed tomography (CT), combined with artificial pneumothorax (pneumothorax CT), was performed in 43 patients with lung cancer in whom conventional CT scans showed that the mass was contiguous to the chest wall (n = 30) and/or mediastinum (n = 25) but without evidence of definite tumor invasion. Invasion was diagnosed on the basis of whether an air space existed between the mass and the adjacent structures. In three patients pneumothorax was not produced. After the procedure, four patients developed symptomatic pneumothorax, and one, subcutaneous emphysema. Comparison of diagnoses based on findings at pneumothorax CT, surgery, and pathologic examination showed that pneumothorax CT is 100% accurate for chest wall invasion and 76% accurate for mediastinal invasion. The authors conclude that this procedure is helpful in accurate evaluation of the T criterion in lung cancer, especially for patients in whom findings at conventional CT suggest tumor invasion of the chest wall and mediastinum.     

Endometrial carcinoma in adenomyosis: assessment of myometrial invasion on T2-weighted spin-echo and gadolinium-enhanced T1-weighted images

OBJECTIVE: The aim of our study was to compare T2-weighted and contrast-enhanced dynamic T1-weighted images with histologic findings in assessing the depth of myometrial invasion by endometrial carcinoma in adenomyosis. MATERIALS AND METHODS: We retrospectively reviewed the MRIs of 11 patients who had a total of 12 lesions of endometrial carcinoma within adenomyosis. T2-weighted and contrast-enhanced dynamic T1-weighted images were compared with the histologic findings separately. We assessed the extent of myometrial invasion by endometrial carcinomas. The depth of myometrial invasion seen on MRI was classified as stage S (superficial invasion), stage D (deep invasion), or undetectable. The staging accuracies of each sequence were assessed. The tumor-myometrium contrast-to-noise ratios were calculated for each sequence. RESULTS: The histologic specimens revealed that myometrial invasion was deep in seven of 12 lesions and superficial in five. On T2-weighted images the depth of invasion was underestimated in two lesions and impossible to determine in five lesions. On dynamic T1-weighted images the depth of invasion was overestimated in one lesion and underestimated in one lesion. The staging accuracy on dynamic T1-weighted images (83%) was significantly higher than that on T2-weighted images (42%). The contrast-to-noise ratio was significantly higher on dynamic T1-weighted studies during the early phase (mean +/- SD, 2.68 +/- 0.94) than it was on T2-weighted studies (1.74 +/- 1.05) and during the delayed phase (2.01 +/- 0.86). CONCLUSION: When adenomyosis coexists with endometrial cancer at the same site on T2-weighted images, contrast-enhanced dynamic T1-weighted imaging improves the accuracy of staging.     

Pelvic phased-array MR imaging of anal carcinoma before and after chemoradiation

The aim of this study was to evaluate the MR findings of anal carcinoma using an external pelvic phased-array coil before and after chemoradiation treatment. 15 patients with carcinoma of the anal canal underwent T(2) weighted and short-tau inversion recovery (STIR) imaging before and after chemoradiation. Images were reviewed in consensus by two radiologists. At pre-treatment imaging, the tumour size and stage, signal intensity and infiltration of adjacent structures were recorded. MR imaging was repeated immediately after chemoradiation, every 6 months for the first year and then yearly. Tumour response was assessed by recording change in tumour size and signal intensity. Prior to treatment, the mean tumour size was 3.9 cm (range, 1.8-6.4 cm). Tumours appeared mildly hyperintense at T(2) weighted and STIR imaging. There was good agreement in T staging between clinical examination and MR imaging (kappa = 0.68). In 12 responders with long disease remission, a greater percentage reduction in the size of MR signal abnormality in the tumour area was observed at 6 months (mean 54.7%; 46-62%) than immediately after treatment (mean 38.6%; 30-46%) (p = 0.002, t-test). 7/12 showed stabilization of T(2) signal reduction in the tumour area after 1 year, and 5/12 showed complete resolution of signal alterations at 2 years. Pelvic phased-array MR imaging is useful for local staging of anal carcinoma and assessing treatment response. After treatment, a decrease in tumour size accompanied by reduction and stability of the MR T(2) signal characteristics at 1 year after chemoradiation treatment was associated with favourable outcome.     

FDG PET for the assessment of myometrial infiltration in clinical stage I uterine corpus cancer

OBJECTIVE: For surgical planning of uterine corpus cancer, prior knowledge of the depth of myometrial invasion is important. Curative tumour resection is possible in superficial invasion (stages IA and IB), while post-surgical chemotherapy or radiation therapy is required in deep invasion (stage IC). We evaluated the value of positron emission tomography with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG PET) for estimating the myometrial invasion in uterine corpus cancer. METHODS: We studied 22 patients with clinical stage I uterine corpus cancer, who underwent FDG PET prior to surgery. Standardized uptake value (SUV; tracer activity per injected dose normalized to body weight) was calculated on the PET image. PET findings were compared with magnetic resonance imaging (MRI) and the surgical staging. RESULTS: The surgical stage was IA in five, IB in 11 and IC in six patients. SUVs in deep invasion (15.69+/-4.73, 8.83-21.84) were significantly higher than those in superficial invasion (9.09+/-3.29, 2.68-15.41) (P<0.005). Using 12.0 as a cut-off value of SUV for the differentiation of these two groups, PET results were correct in 19 patients but were incorrect in three patients. Although both PET and MRI provided correct staging in 14 patients, only MRI overestimated the myometrial invasion in four patients with stage IB and showed inconclusive findings in one patient with stage IC. Four of these five patients were post-menopausal. CONCLUSIONS: The cut-off value of SUV (=12.0) may be a useful index for the differentiation of superficial invasion and deep invasion. FDG PET may be feasible for predicting the myometrial infiltration of uterine corpus cancer, especially when uterine atrophy makes it difficult at MRI in post-menopausal patients.     

Superficial esophageal carcinoma: an in vitro study of high-resolution MR imaging at 1.5T

The purpose of this study was to determine the diagnostic accuracy of high-resolution MR imaging at 1.5T for evaluating the mural invasion of superficial esophageal carcinoma. Forty-one esophageal specimens taken from patients suspected of having superficial carcinoma were studied using a 1.5T MR system with a surface coil. Spin-echo MR images were obtained with a field of view of 50mm, matrix of 256 x 256, and section thickness of 2mm (voxel size = 0.08 mm3). MR findings were compared with histopathologic findings. T2-weighted images clearly depicted the normal esophageal wall as consisting of 8 layers. In 39 (95%) of 41 carcinomas, the depth of mural invasion determined by MR imaging correlated well with that determined with histopathologic examination. The MR-based stage was higher in 2 (5%) cases than the histopathologic stage. High-resolution MR imaging at 1.5T shows a high diagnostic accuracy for evaluating the mural invasion of superficial esophageal carcinoma, thus potentially enabling preoperative histopathologic staging.     

Myometrial invasion by endometrial carcinoma: assessment with plain and gadolinium-enhanced MR imaging.

A prospective study was designed to determine the sensitivity and specificity of nonenhanced T2-weighted and contrast material-enhanced T1-weighted magnetic resonance (MR) imaging in assessing the depth of myometrial invasion in patients with proved endometrial cancer. In 56 consecutive patients with clinically determined early-stage disease, findings of the two MR imaging techniques were compared with results of histologic examination of surgical specimens. Myometrial invasion was classified as absent (stage IA), superficial (stage IB), or deep (stage IC). In the assessment of each tumor stage, the sensitivity and specificity of contrast-enhanced T1-weighted MR imaging were higher than those of non-enhanced T2-weighted MR imaging. In determining the degree of myometrial tumor invasion, the overall sensitivity of enhanced T1-weighted MR imaging was 87.5%, whereas that of nonenhanced T2-weighted MR imaging was 71.4% (P less than .05). The use of contrast material may improve the ability to assess, with MR imaging, the depth of myometrial invasion by endometrial cancer.     

Diagnosis of the depth of invasion of esophageal carcinoma using digital radiography

OBJECTIVE: The purpose of our investigation was to determine the usefulness of digital radiography (DR) for diagnosing the depth of invasion of esophageal carcinoma. METHODS: We evaluated 59 patients with esophageal carcinomas who underwent DR. During continuous DR in tangential views, the most distended image of the esophagus was chosen. Percent esophageal stenosis (PES) was based on the diameter across the lesion of maximal narrowing and the average of the normal oral and anal side diameters. The maximal thickness of the tumor was measured on sequentially prepared specimens. We evaluated whether the percent of esophageal stenosis correlated with the maximal thickness of the tumor on histologic findings. Receiver-operating characteristic (ROC) curves were constructed to establish the cut-off level for PES in diagnosing the depth of tumor invasion. Accuracies for the depth of the invasion were calculated based on PES using DR. For the accuracy rate, DR was compared with endoscopy and endoscopic ultrasonography (EUS). RESULTS: There was a close correlation between PES and pathological thickness of the tumor. PES values (mean+/-S.D.) were 2.45+/-0.75% in Tis and T1a tumors, 13.3+/-10.9% in T1b tumors, 35.2+/-11.1% in T2 tumors, 55.2+/-18.1% in T3 tumors, and 86.1+/-7.5% in T4 tumors. Using the ROC analysis, 12.5, 37.5, and 44.4% were the highest cut-off values of PES for differentiating < or =T1a, < or =T1b, and < or =T2 tumors. Regarding T staging, 45 (76%) of 59 lesions were staged correctly with EUS, whereas 47 (80%) were staged correctly with DR. CONCLUSION: DR is useful for diagnosing the depth of the invasion because esophageal stenosis calculated using DR is an objective index of tumor infiltration. The accuracy rate of the depth of invasion with DR was as good as that of EUS.     

Staging of urinary bladder neoplasms with MR imaging: is Gd-DTPA helpful?

This study was performed to investigate whether intravenous administration of Gd-DTPA can improve the accuracy of MR imaging in the detection and staging of bladder neoplasms. In 68 patients with suspected urinary bladder neoplasms, MR examinations were performed with T1-weighted SE sequences before and after intravenous administration of Gd-DTPA. The findings were compared with surgical staging using the TNM classification. Overall staging accuracy of contrast enhanced MR was 46%; if stages Ta-T3a were combined into one group, the accuracy was 69%. Accuracy was low (19%) in tumors without muscular bladder wall invasion (Ta). In cases with extravesical spread (greater than or equal to T3b), the accuracy of staging was 87%. Contrast enhanced MR detected extravesical extension of tumor with a sensitivity of 93% and a specificity of 95%. Contrast enhancement increased the sensitivity for detection of urinary bladder neoplasms from 70% on precontrast T1-weighted scans to 79% on postcontrast scans. In comparison with T2-weighted scans, the Gd-DTPA enhanced T1-weighted scans had better image quality and lower acquisition times.     

Bright echogenic foci in early prostatic carcinoma: sonographic and pathologic correlation

One hundred sixty patients with biopsy-proved clinical stage A or B prostatic carcinoma were examined with high-resolution transrectal ultrasonography prior to radical prostatectomy. All tumors showed either a hypoechoic or isoechoic echo pattern. However, 11 patients demonstrated evidence of focal bright echogenic areas at the periphery or within the center of a hypoechoic tumor. Coarse echogenic foci seen in seven patients corresponded pathologically to calcified corpora amylacea in benign tumors of the prostate gland either at the edge of the tumor or scattered throughout the tumor. Seven patients showed a fine, stippled echogenic pattern within the lesion. On a pathologic level, this pattern represented high-grade tumors with extensive central comedonecrosis and calcifications in five patients and an unusual deposit of small intraluminal crystalloid deposits in two patients. Combinations of echo patterns were observed in three patients. This study demonstrates that echogenic foci can be seen within predominantly hypoechoic tumor nodules. Coarse bright echoes, usually at the periphery of the tumor, suggest calcifications in benign prostate glands. Tumor calcifications and intraluminal prostatic crystalloid deposits were located more centrally and had a finer stippled sonographic appearance.     

联合应用MR动态增强及T_2WI对Ⅰ、Ⅱ期子宫内膜癌的诊断价值

目的:评价MR动态增强、T2WI二者结合对Ⅰ、Ⅱ期子宫内膜癌的诊断价值。方法:回顾性分析36例经手术病理证实的子宫内膜癌的T1WI、T2WI和动态增强图像,将MRI判断肌层和宫颈侵犯结果与手术病理比较。结果:MRI动态增强及T2WI二者结合判断子宫内膜癌浸润深度诊断符合率为80.6%,对Ⅰa期的敏感性、特异性,阳性预测值、阴性预测值分别为85.7%、93.1%、75%、96.4%;Ⅰb期的敏感性、特异性,阳性预测值、阴性预测值分别为76.5%、84.2%、81.3%、80%;Ⅰc期的敏感性、特异性,阳性预测值、阴性预测值分别为83.3%、91.7%、83.3%、91.7%;Ⅱ期的敏感度为80%,特异度为96.8%,诊断符合率为94.4%。结论:联合应用MRI动态增强及T2WI判断子宫内膜癌侵犯肌层的深度、范围有很高的临床价值,能够指导临床治疗方式的选择。     

MRI of local disease in nasopharyngeal carcinoma: tumour extent vs tumour stage

The purpose was to use MRI to study in detail local tumour extension in patients presenting with nasopharyngeal carcinoma (NPC) and to compare the extent of local disease with the current T-stage classification. MR images of 150 patients with newly diagnosed nasopharyngeal carcinoma were obtained on a 1.5 T unit. 10 extranasopharyngeal sites were analysed for tumour involvement. The number of concurrently involved sites was determined. The extent of tumour invasion was compared with staging as defined by the fifth edition of the AJCC classification. The T-stage distribution was T1 21%, T2 16%, T3 41% and T4 22%. The frequencies of tumour invasion into an individual site, and the mean number of other concurrently involved sites were as follows: skull base 63%, 3.9 sites; parapharyngeal 56%, 3.9 sites; nasal cavity 53%, 4.0 sites; oropharyngeal 17%, 5.2 sites; sphenoid sinus 27%, 5.6 sites; cranium 21%, 5.7 sites; infratemporal fossa 2%, 6.3 sites; ethmoid sinus 14%, 6.5 sites; orbit 5%, 7.0 sites; maxillary sinus 5%, 7.1 sites; and hypopharynx 0%, 0 sites. Extranasopharyngeal extension commonly occurred superiorly into the skull base rather than inferiorly to the oropharynx (p < 0.0001). Anatomical sites defined within the same T-stage category had different frequencies of involvement and different frequencies of concurrently involved sites. Oropharyngeal involvement (T2 stage) was associated with a number of concurrently involved sites comparable to structures in the T3 category. Maxillary and ethmoid sinus involvement (T3 stage) were associated with a number of involved sites comparable to the T4 stage. Invasion of the maxillary antrum and orbit are markers of the most bulky form of NPC.     

Prognostic significance of MRI-detected bladder muscle and/or serosal invasion in patients with cervical cancer treated with radiotherapy

In cervical cancer, the prognostic significance of bladder wall invasion on MRI without pathological evidence of mucosal invasion is not known. From 454 consecutive patients with cervical cancer who were treated with radiation, we reviewed images and analysed the outcome of 92 patients with the Federation of International Gynecology and Obstetrics (FIGO) stage IIIB–IVA. We analysed the patients in three groups, normal, wall (muscle and/or serosal) invasion and mucosal invasion, according to the findings on the MRI. Kaplan–Meier life table analysis and the log-rank test were used to assess the survival rates and differences according to prognostic factors. MRI detected abnormalities in the bladder wall in 42 patients (45.6%): wall invasion in 24 and mucosal invasion in 18. 5 of 18 patients, suspected on MRI to have mucosal invasion, showed no pathological evidence of mucosal invasion. Median follow-up period was 34 months. 3-year cause-specific survival (CSS) in the normal group compared with the wall invasion group was 76.2% vs 71.4% (p = 0.48). 3-year CSS for the wall invasion group compared with the mucosal invasion group was 71.4% vs 54.3% (p = 0.04). Mucosal invasion on MRI (p = 0.03) and concurrent chemoradiotherapy (p = 0.01) was significant for CSS. The prognosis for patients with cervical cancer with evidence of muscle and/or serosal invasion of the bladder on MRI may not differ from that for patients without abnormality on MRI. In patients with the MRI finding of bladder mucosal invasion, further studies should be conducted regarding the role of cystoscopy to determine the need for pathological confirmation.According to the 2006 report by the Federation of International Gynecology and Obstetrics (FIGO) [1], the 5-year survival of patients with stage IVA cervical cancer is about half that of patients with stage IIIB cervical cancer (22.0% vs 41.5%). Reviewing the hazard ratios for patients with stages IIB, IIIB and IVA (2.7, 5.3 and 11.7, respectively), we noted a sharp increase in hazard ratio for stage IVA relative to stage IB. Because as the stage increases, the impact of lymph node involvement or tumour size on survival outcome decreases [1], mucosal involvement of the bladder and/or rectum may potentially have a strong influence on survival.During the past two decades, there have been changing trends not only in the incidence of uterine cervical cancer [2] but also in the process of staging work-up. As MRI has become more applicable in planning the treatment of cervical cancer [3, 4], previously unnoticed invasion of the posterior wall of the urinary bladder without cystoscopic evidence of mucosal invasion appears frequently in advanced disease. However, there have been no published reports regarding the frequency of these findings or the prognosis for these patients with abnormal bladder wall findings on MRI without cystoscopic evidence of mucosal invasion.Evidence suggests that MRI may predict the extent of disease more accurately than clinical staging [5]. With regard to bladder invasion, studies specifically tested the diagnostic accuracy of MRI against cystoscopic examination and/or surgical sampling as reference standards [6–10]. However, non-mucosal invasion cannot be diagnosed with cystoscopy, but can be confirmed only by exploration, which is not usually performed for locally advanced cervical cancer. For this reason, it is difficult to determine the diagnostic accuracy of MRI.Following radiotherapy for advanced-stage tumours, MRI performance can be assessed only with clinical outcome. Few studies have reported on the use of MRI in cervical carcinoma treated with radiotherapy, and most have focused on the relationship between outcome and tumour diameter, tumour volume or lymph node status. We investigated the prognostic significance of abnormal bladder wall findings on MRI, with particular attention to those patients without cystoscopic evidence of mucosal invasion.     

3.0T MR高分辨率成像对直肠癌局部浸润的术前影像学评价

目的 探讨3.0T MR高分辨率成像在直肠癌术前局部浸润的评估价值.方法 回顾性分析经手术病理证实的直肠癌患者168例,术前均行MRI常规盆腔、直肠高分辨成像.评价3.0T MR高分辨成像术前T分期的准确性;探讨T3期直肠癌局部浸润特征性影像学表现.结果 直肠癌累及肠周径程度与病理T分期呈中等正相关(rs=0.530, P=0.003).MRI直肠癌T分期与病理T分期比较,总体诊断准确度为84.52%,各分期MRI征象与病理T分期有较强的相关性(rs=0.837,P=0.001).MRI诊断T3期直肠癌中,各单一征象以肿瘤结节样外凸特异性最高(91.1%),肌层信号中断灵敏度最好(89.7%).而各叠加征象中则以肠壁索条影+肌层信号中断特异性最高(89.3%),灵敏度最好(78.0%).结论 3.0T MR高分辨成像能较好显示直肠癌局部浸润表现,对术前T分期有一定的临床应用价值.     

CT对膀胱癌术前评估与术后随访的意义

目的：探讨膀胱癌术前分期与术后随访中CT的价值。材料与方法：分析39例膀胱癌CT资料,将其分为4型,并与手术、病理对照基底浸润深度、邻近侵犯和术后复发的表现。结果：乳头状有蒂5例,非乳头状有蒂6例,乳头状宽基底5例,非乳头状宽基底13例;浸润粘膜层5例,粘膜下层及浅肌层各6例,深肌层5例,浆膜或纤维膜及膜外3例;邻近侵犯16例;术后复发/再发17例,输尿管扩张8例,淋巴结转移3例。结论：膀胱癌浸润粘膜层与粘膜下层表现相似;浅肌层和深肌民支受侵可参考间接征象有助于诊断;浆膜或纤维膜及膜外受侵时,其表面不光滑呈齿状或纤维条索状粘连;膀胱癌腔内最常侵犯输尿管入口;薄层扫描能显示胶胱壁受侵。     

Sonography of adenomyomatosis of the gallbladder: radiologic-pathologic correlation

Sonograms of six patients with adenomyomatosis of the gallbladder were reviewed and correlated with oral cholecystographic and pathologic findings. The gallbladder was visualized in four of the six patients by oral cholecystography, which also revealed intramural diverticula. Five of the six patients showed sonographic evidence of diffuse or segmental thickening of the gallbladder wall and intramural diverticula, seen as anechoic or echogenic foci within the wall. Intramural diverticula containing bile appeared as anechoic spaces; those containing biliary sludge or gallstones appeared as echogenic foci with or without acoustic shadows or reverberation artifacts. There was good correlation between sonographic and pathologic findings in three patients. The authors conclude that adenomyomatosis of the gallbladder should be suspected when (a) there is diffuse or segmental thickening of the gallbladder wall and (b) intramural diverticula are seen as anechoic or echogenic foci with or without associated acoustic shadows or reverberation artifacts.     

High-resolution cranial ultrasound in the shaken-baby syndrome

With limited near-field resolution and accessible acoustic windows, sonography has not been advocated for assessing central nervous system injuries in the shaken-baby syndrome. Our purpose was to correlate high-resolution ultrasonographic characteristics of central nervous system injuries in whiplash injuries and the shaken-baby-syndrome with MRI and CT. Ultrasonographic images of 13 infants, aged 2–12 months, with whiplash or shaking cranial trauma were reviewed and compared with MRI in 10 and CT in 10. Five patients had serial ultrasonography and MRI or CT follow-up from 1 to 4 months after the initial injury. With ultrasonography we identified 20 subdural haematomas. MRI and CT in 15 of these showed that four were hyperechoic in the acute stage, three were mildly echogenic in the subacute stage, and that one subacute and seven chronic lesions were echo-free. Five patients had acute focal or diffuse echogenic cortical oedema which evolved into subacute subcortical hyperechoic haemorrhage in four, and well-defined chronic sonolucent cystic or noncystic encephalomalacia was seen at follow-up in two. Using ultrasonography we were unable to detect two posterior cranial fossa subdural haematomas or subarachnoid haemorrhage in the basal cisterns in three cases, but did show blood in the interhemispheric cistern and convexity sulci in two. Ultrasonography has limitations in demonstrating abnormalities remote from the high cerebral convexities but may be a useful adjunct to CT and MRI in monitoring the progression of central nervous system injuries in infants receiving intensive care. Received: 25 October 2000 Accepted: 25 October 2000     

Primary thyroid lymphoma: comparison of CT and US assessment

Sixteen patients with primary thyroid lymphoma were studied with computed tomography (CT) and ultrasonography (US), and findings were compared. In 13 of 16 patients, detection of the primary tumor with US and CT were comparable. US was superior in one case, and CT in another. One tumor was not detected with either technique. Thyroid lymphomas appeared as extremely hypoechoic masses intermingled with echogenic structures. Although echogenicity of unaffected thyroid tissue was also low because of coexisting Hashimoto thyroiditis, thyroid lymphomas were relatively well differentiated as markedly hypoechoic areas. Five tumors showed contiguous spread into both thyroid lobes. US and CT were equally sensitive in detection of superficial lymphomatous nodes (seven of 16 cases). CT was superior to US in the definition of tumor extent in two patients with intrathoracic tumor extension and in one with laryngeal invasion. In patients with suspected thyroid lymphoma, CT should be the primary radiologic technique used for diagnosis and staging; US will be useful in local follow-up.