De novo development of presumed cavernomas following resolution of E. Coli subdural empyemas

Cavernomas fall within the group of angiographically occult lesions and may be found in up to 4 % of the population [1]. They may occur at any age, and with the advent of MRI incidental cavernomas are increasingly identified. The pathogenesis is uncertain. Familial cases are well recognised with a reported prevalence of 10–15 % [2–3]. The incidence of new lesions has been reported at 0.4 lesions per patient per year in cases with familial cavernomas [4]. Presumed cavernomas have been documented following radiation for malignancy [5–6], and sterotactic cerebral biopsy [7]. There have been no previously documented cases of de novo genesis of cavernomas following bacterial meningitis and subdural empyemas. Received: 18 November 1999/Accepted: 11 February 2000     

MR-guided percutaneous excisional and incisional biopsy of breast lesions

The aim of this study was the realisation and clinical application of MR-guided vacuum biopsy for percutaneous excisional and incisional biopsy of enhancing breast lesions. A breast biopsy system and procedure have been developed which allow precise and safe access to breast lesions in any location and use of vacuum biopsy (VB) under MR guidance. Fifty-one patients with 55 MR-detected lesions were examined. Verification of these diagnoses included re-excision histology of all 14 malignancies and for benign lesions retrospective correlation of histology and imaging, assessment of complete or partial removal of the enhancing area directly after VB (40 of 40 lesions) and follow-up MRI (33 of 40 lesions), which in contrast to conventional needle biopsy can be used as proof of representative removal. Fifty-four of 55 procedures (including 15 lesions ≤ 5 mm and another 26 lesions of 5–10 mm size) were successful. One failure was caused by incorrect use of the VB gun. Vacuum biopsy yielded 14 malignancies and 40 benign lesions. With the available verification techniques all diagnoses proved correct. Percutaneous VB became possible under MR guidance. With minimal invasion it allowed increased certainty and accuracy even for very small lesions. Received: 17 August 1998; Revised: 15 January 1999; Accepted: 10 February 1999     

Percutaneous mitoxantrone injection for primary and secondary liver tumors: Preliminary results

Purpose: To determine the effects of percutaneous intratumoral chemotherapy with mitoxantrone (PIM) in the palliative treatment of malignant liver lesions. Methods: We treated 15 progressive lesions in nine patients in whom either previous therapy failed or serious complications developed as a result. Seven lesions were metastatic and eight were due to foci of hepatocellular carcinoma. Under computed tomography (CT) guidance, we percutaneously injected 10–20 mg of mitoxantrone mixed with 0.5 ml of contrast medium into the tumor, performing one to three treatments at intervals of 1 month. Results: There were no complications. The morphologic responses of the tumors after treatment were: minor response in one case, no change in 11 cases, progressive disease in three cases. Mitoxantrone induced tumor necrosis with no viable cancer tissue in eight of 11 biopsies. Recurrence was observed in nine of the treated lesions 2–9 months after treatment. New lesions were observed in five of nine patients 1–9 months after treatment. Conclusion: In patients with malignant liver lesions with no other therapeutic possibilities, minimally invasive intratumoral mitoxantrone injection was carried out safely with good tumor delivery of chemotherapy, and tumor necrosis was demonstrated at biopsy. We feel this approach warrants further investigation.     

Breast lesions with imaging-histologic discordance during US-guided 14G automated core biopsy: can the directional vacuum-assisted removal replace the surgical excision? Initial findings

The purpose of this study was to determine the frequency of carcinoma at percutaneous directional vacuum-assisted removal (DVAR) in women with imaging-histologic discordance during ultrasound (US)-guided automated core needle biopsy, and to determine the role of DVAR in breast lesions with imaging-histologic discordance. A US-guided 14-gauge automated core needle biopsy was performed on 837 consecutive lesions. Imaging-histologic discordance was prospectively considered in 33 of 634 benign biopsies. DVAR was recommended in those lesions. Among the 33 lesions, 26 lesions that underwent subsequent DVAR or surgical excision made up our study population. Medical records, imaging studies, and histologic findings were reviewed. Among the 26 lesions, 18 lesions underwent subsequent US–guided DVAR, with 8-gauge probes for 15 of the lesions, and 11-gauge for three of the lesions. Two lesions were diagnosed as having carcinoma (2/18, 11.1% of upgrade rate; 3.1–32.8% CI). The remaining eight lesions underwent subsequent surgical excision, and carcinoma was diagnosed in one case (12.5% of upgrade rate; 2.2–47.1% CI). A US-guided DVAR of the breast mass with imaging-histologic discordance during US-guided 14-gauge automated core needle biopsy is a valuable alternative to surgery as a means of obtaining a definitive histological diagnosis. An erratum to this article can be found at     

Histologic microbiopsy with 14 G needle in the diagnosis of breast lesions. Experience with 1000 cases

PURPOSE: We report our experience with large core biopsy (LCB: 14-Gauge needles) of questionable or suspicious breast lesions detected at mammography and/or US. All biopsies were performed under instrumental guidance. We also report on technique, costs, time, advantages and disadvantages of the method and, finally, give precise indications on when and why large core biopsy is needed. MATERIAL AND METHODS: From january 1996 to may 2000 we performed 1000 microhistologic biopsies on breast lesions at the Unità Integrata di Senologia, Azienda Ospedaliera Careggi, Florence; 650 (65%) were non palpable lesions. Large core needles were used (14-Gauge caliber). In the majority of cases (70%) we used US guidance, in the others a stereotactic guidance was employed. RESULTS: Microhistologic biopsy allowed accurate characterization in most cases. Inadequate samples were obtained in 15 cases. The false negative rate was 6%. Surgery was needed to characterize the lesion unquestionably in 13 cases only. CONCLUSION: In agreement with literature reports, our results confirm large core biopsy as an adequate alternative to surgical biopsy and, to some extent, to FNAC, thanks to its moderate invasiveness, low costs, short execution time, little patient discomfort and high sensitivity (93.98%) and specificity (99.7%).     

MR-guided liver biopsy within a short, wide-bore 1.5 Tesla MR system

The purpose of this study was to evaluate the diagnostic efficacy of magnetic resonance (MR)-guided biopsy of focal liver lesions within a short, wide-bore 1.5-T MR system and to determine the duration and accuracy of needle placement using MR fluoroscopy guidance in 25 patients. Accuracy of needle placement was evaluated in two orthogonal planes, and the out-of-plane angle of needle deflection was measured. Needle positioning was characterised subjectively as centred, peripheral, or exterior relative to the lesion. Exterior positioning was corrected by a step-by-step procedure. Surgical resection (n = 6), previous histologies (n = 8), or clinical/radiological follow-up (n = 11) served as the ‘gold standard’. The guidance needle could be placed successfully using MR fluoroscopy in 20 of 25 patients (80%). Needle placement was rated as ‘centred’ in 11 and as ‘peripheral’ in nine patients. Median needle deflection was 2.6 degrees, with a median deviation of 3.4 mm. In five patients, the direct approach failed or was rated as ‘exterior’; therefore, repositioning after needle stabilisation with a stainless-steel stylet was necessary. The diagnostic yield of all biopsies was: sensitivity 95.5%, specificity 100.0% and accuracy 96.0%. In conclusion, MR-guided biopsies in a short, wide-bore MR system yielded highly reliable biopsy results, and in most cases the direct approach with MR fluoroscopy guidance proved to be fast and accurate.     

Percutaneous RF Thermal Ablation of Renal Tumors: Is US Guidance Really Less Favorable Than Other Imaging Guidance Techniques?

The purpose of this study was to compare our experience with ultrasound (US)-guided percutaneous radiofrequency thermal ablation (RFA) of renal tumors with results of CT-guided and MRI-guided series in the current literature. Of 90 consecutive renal tumors treated with RFA in 71 patients, 87 lesions were ablated under US guidance. We performed a retrospective analysis of clinical outcome and safety. Results were then compared to published case series where CT and MRI guidances were used exclusively. In our series we had a major complication rate of 4.6%, whereas in CT- and MRI-based series it was 0–12% (mean, 2.2%) and 0–8.3% (mean, 4.1%), respectively. During follow-up (1–68 months; mean, 24 months) technical effectiveness was 89.7%, while it was between 89.5% and 96% in CT-guided series and between 91.7% and 100% in MRI-guided series. The size of successfully treated lesions (28 mm) was lower than that of partially-ablated lesions (36 mm; p = 0.004) and only central lesion location proved to be a negative prognostic factor (p = 0.009); in CT-guided series, positive prognostic factors were exophytic growth and size ≤3 cm. “Tumor-specific” 2-year survival was 92% in our series, 90–96% in CT-guided series, and not reported in MRI-guided series. In conclusion, despite common beliefs, US guidance in RFA of renal tumors is not less favorable than other guidance techniques. Thus the interventional radiologist can choose his or her preferred technique taking into account personal experience and available equipment.     

Can galactography-guided stereotactic, 11-gauge, vacuum-assisted breast biopsy of intraductal lesions serve as an alternative to surgical biopsy?

The purpose of this study was to determine the value of galactography-guided, stereotactic, vacuum-assisted breast biopsy (VABB) for the assessment of intraductal breast lesions and its potential as a therapeutic tool that could eliminate the need for surgical excision. Eighteen patients (median age 64 years, range 37–80) with nipple discharge and galactography-verified intraductal lesions underwent galactography-guided, stereotactic, 11-gauge VABB followed by surgery. Histopathology findings from VABB and subsequent surgery were compared. Underestimation and false-negative rates were assessed. After VABB, histopathology revealed invasive ductal carcinoma (IDC) in three (17%), ductal carcinoma in situ (DCIS) in six (33%), high-risk lesions in six (33%) and benign lesions in three (17%) cases. After surgical biopsy, histopathology confirmed the previously established diagnosis in 11 lesions (61%). The underestimation rate for high-risk lesions and DCIS was 50% (6/12). The false-negative rate was 7% (1/14). Histopathology examination after surgery showed that not a single lesion had been completely removed at VABB. Galactography-guided VABB is a feasible diagnostic tool. However, its value as a therapeutic procedure is limited because of the high number of underestimated and missed lesions and because of the histopathological detection of lesions’ remnants in every case. Surgical excision should be the therapeutic gold standard in cases of pathological nipple discharge and galactography abnormalities.     

Minimally invasive stereotaxic vacuum core breast biopsy

The purpose of our study was the assessment of the diagnostic value of vacuum core biopsy, which promises high accuracy by minimally invasive percutaneous excision of 1–2 cm³ of tissue. The materials used were a digital stereotaxic biopsy table (Fischer Imaging) and a Mammotome-gun (Biopsys). A total of 236 patients with 261 predominantly indeterminate lesions (indeterminate: 230; suspicious: 26; malignant: 5) underwent vacuum core biopsy (VCB). Verification was as follows: (a) demonstration of complete or partial removal of the lesion or replacement of the lesion by a small hematoma by comparison of the pre- and post-VCB mammogram; (b) reexcision of 45 malignant and 6 borderline lesions; (c) radiologic–histologic correlation; and (d) 6-month-follow-up mammograms in 129 cases. Two VCBs were not possible because very fine microcalcifications could not be visualized. Two puncture errors occurred which, however, were immediately recognized and VCB was repeated. Based on the above verification a 100 % accuracy was achieved. No relevant side effects occurred. Except for 2 cases mammographically hardly any scarring was visible. Based on the excellent accuracy and excellent tolerance of the procedure VCB appears to be the future method of choice for the workup of those indeterminate mammographically detected lesions that up to now have still required surgical biopsy. Received 5 September 1997; Accepted 12 September 1997     

Freehand Two-Step CT-Guided Brain Tumor Biopsy: A Fast and Effective Interventional Procedure in Selected Patients

Purpose To evaluate the efficacy and safety of CT-guided needle biopsy of brain lesions without a stereotactic device, and to determine the best possible indications for this technique. Methods From February 2001 to February 2004, 20 patients (12 men, 8 women; age 61–82 years) underwent CT-guided brain lesion biopsy. The procedure started with a brain CT scan for lesion localization and for selection of the inlet for needle insertion. The patient was then transported to the operating room where cranioanatrisis was performed. Subsequently, the biopsy was performed under CT guidance using a 14G brain biopsy needle with a blind smooth end and lateral holes. At the end of the biopsy, the field was checked for possible complications with a CT scan. Results Histopathologic results were: brain tumor in 16 patients (80%), inflammatory process in 3 (15%), and no conclusive diagnosis in 1 (5%). A repeat of the process was required in 2 patients. A minor complication of local hematoma was found in 1 patient (5%). There were no deaths or other serious complications. Conclusion CT-guided biopsy is a reliable method for histopathologic diagnosis of brain lesions in selected cases. It is a simple, fast, effective, low-cost procedure with minimal complications, indicated especially for superficial and large tumors.     

Preliminary experience with interactive guided brain biopsies using a vertically opened 0.5-T MR system

The purpose of our study was to evaluate the feasibility and accuracy of brain biopsies performed within a vertically opened MR system. We worked with the interventional 0.5-T MR “SIGNA SP” (General Electric Medical Systems, Milwaukee, Wis.) with an integrated tracking device “Flashpoint Position Encoder” (Image Guided Technologies, USA). As a holding device for this instrument we constructed a special frame. The whole system allows an exact adjustment of an optimum biopsy direction and guidance of the biopsy in a non-stereotactic, interactive mode in near real-time. As biopsy tools we used MR-compatible aspiration and specially made side-cut needles (Daum, Germany; E-Z-EM, USA). We performed a prospective diagnostic brain biopsy study in 18 patients. Guidance of the needle was carried out using gradient-echo single-slice technique. The sample was taken after controlling the exact position of the needle tip on spin-echo images. In 12 cases an exact neuropathological diagnosis was possible. In 6 cases of negative biopsy (4 aspiration biopsies) the samples were not representative. Our results demonstrate the feasibility of interactive MR-guided minimally invasive brain biopsies in an open MR system. The best results were achieved using cut needles for biopsies of contrast-enhancing lesions visible on T1-weighted gradient-echo guidance sequence. Received: 2 February 1998; Revision received: 13 July 1998; Accepted: 2 September 1998     

Diagnostic impact of 18F-FDG PET–CT evaluating solid pancreatic lesions versus endosonography, endoscopic retrograde cholangio-pancreatography with intraductal ultrasonography and abdominal ultrasound

Purpose  This prospective single-centre phase II trial assessed the diagnostic impact of ¹⁸F-FDG PET–CT in the evaluation of solid pancreatic lesions (∅ ≥10 mm) compared to endosonography (EUS), endoscopic retrograde cholangio-pancreatography (ERCP) with intraductal ultrasound (IDUS), abdominal ultrasound (US) and histopathological reference. Methods  Forty-six patients (32 men/14 women, ∅ 61.7 years) with suspected pancreatic neoplasms underwent PET–CT with contrast-enhanced biphasic multi-detector CT of the upper abdomen followed by a diagnostic work-up with EUS, ERCP with IDUS and US within 3 weeks. PET–CT data sets were analysed by two expert readers in a consensus reading. Histology from surgery, biopsy/fine-needle aspiration and/or clinical follow-up ≥12 months served as standard of reference. Results  Twenty-seven pancreatic malignancies were histopathologically proven; 19 patients had benign diseases: 36/46 lesions (78%) were detected in the head of the pancreas, 7/46 and 3/46 in the body and tail region, respectively. Sensitivity and specificity of PET–CT were 89% and 74%, respectively; positive predictive value (PPV) and negative predictive value (NPV) were 83% and 82%, respectively. Sensitivity (81–89%), specificity (74–88%), PPV (83–90%) and NPV (77–82%) achieved by EUS, ERCP and US were not significantly different. PET analysis revealed significantly higher maximum mean standardised uptake values (SUV_max 6.5 ± 4.6) in patients with pancreatic malignancy (benign lesions: SUV_max 4.2 ± 1.5; p < 0.05). PET–CT revealed cervical lymphonodal metastasis from occult bronchogenic carcinoma and a tubular colon adenoma with intermediate dysplasia on polypectomy, respectively. Conclusions   ¹⁸F-FDG PET–CT achieves a comparably high diagnostic impact evaluating small solid pancreatic lesions versus conventional reference imaging modalities. Additional clinical diagnoses are derived from concomitant whole-body PET–CT imaging. Verena Schick and Christiane Franzius contributed equally to this work.     

Evaluation of the vascular pattern of hepatocellular carcinoma with dynamic computed tomography and its use in identifying optimal temporal windows for helical computed tomography

The aim of this work was to study the vascularization of hepatocellular carcinoma (HCC) by means of dynamic CT and to demonstrate the existence of optimal temporal windows for visualization of HCC in order to develop new protocols for helical CT of the liver. We studied, by means of dynamic CT, 42 histologically proved HCCs in 30 patients after injecting contrast medium (100 ml, 3 ml/s). We performed a time–density analysis of the aorta, liver, portal vein, spleen and lesion. We identified three temporal curves of attenuation of the neoplastic tissue. Curve 1 was three-phasic: hyperattenuation, isoattenuation and hypoattenuation; curve 2 was two-phasic: hyperattenuation and isoattenuation; curve 3 was two-phasic: isoattenuation and hypoattenuation. Thirty-two lesions were homogeneous (curve 1 in 22 cases, 68.7 %; curve 2 in 7 cases, 21.8 %; curve 3 in 3 cases, 9.4 %), whereas 10 lesions were non-homogeneous. Two optimal temporal windows were identified: the first, with predominantly hyperattenuating lesions (range 29–65 s, 90.4 % sensitivity); the second, with predominantly hypoattenuating lesions (range 132.1–360 s, 76.1 %). There is an interposed time range of reduced visualization (range 62–127 s, 54.7 %) in which lesions are isoattenuating. Combined CT study during the first and second temporal windows improves the detection of HCCs especially for homogeneous and small lesions. The intermediate isoattenuation time range does not increase lesion detection rate. Received: 22 March 1996; Revision received 3 September 1996; Accepted 21 March 1997     

Accuracy of whole-body low-dose multidetector CT (WBLDCT) versus skeletal survey in the detection of myelomatous lesions,and correlation of disease distribution with whole-body MRI (WBMRI)

Aim  The aim of the study is to assess the feasibility of whole-body low-dose computed tomography (WBLDCT) in the diagnosis and staging of multiple myeloma and compare to skeletal survey (SS), using bone marrow biopsy and whole-body magnetic resonance imaging (WBMRI; where available) as gold standard. Materials and methods  Patients referred over an 18-month period for investigation of suspected multiple myeloma or restaging of myeloma were randomized to undergo one of two WBLDCT protocols using high kVp, low mAs technique (140 kVp, 14 mAs; or 140 kVp, 25 mAs). Recent WBMRI scans were reviewed in 23 cases. Each imaging modality was assessed by two radiologists in consensus and scored from 0–3 (0 = normal, 1 = 1–4 lesions, 2 = 5–20 lesions, 3 ≥ 20 lesions/diffuse disease) in ten anatomical areas. Overall stage of disease, image quality score, and the degree of confidence of diagnosis were recorded. Diagnostic accuracy of skeletal survey and WBLDCT were determined using a gold standard of bone marrow biopsy and distribution of disease was compared to WBMRI. Results  Thirty-nine patients were evaluated. WBLDCT identified more osteolytic lesions than skeletal survey with a greater degree of diagnostic confidence and led to restaging in 18 instances (16 upstaged, two downstaged). In those with recent WBMRI, distribution of disease on WBLDCT showed superior correlation with WBMRI when compared with SS. Overall reader impression of stage on WBLDCT showed significant correlation with WBMRI (κ = 0.454, p < 0.05). WBLDCT provided complementary information to WBMRI in nine patients with normal marrow signal following treatment response, but which were shown to have diffuse residual cortical abnormalities on CT. Conclusion  WBLDCT at effective doses lower than previously reported, is superior to SS at detecting osteolytic lesions and at determining overall stage of multiple myeloma, and provides complementary information to WBMRI.     

Impact of the Kaiser score on clinical decision-making in BI-RADS 4 mammographic calcifications examined with breast MRI

To investigate whether the application of the Kaiser score for breast magnetic resonance imaging (MRI) might downgrade breast lesions that present as mammographic calcifications and avoid unnecessary breast biopsies This IRB-approved, retrospective, cross-sectional, single-center study included 167 consecutive patients with suspicious mammographic calcifications and histopathologically verified results. These patients underwent a pre-interventional breast MRI exam for further diagnostic assessment before vacuum-assisted stereotactic-guided biopsy (95 malignant and 72 benign lesions). Two breast radiologists with different levels of experience independently read all examinations using the Kaiser score, a machine learning–derived clinical decision-making tool that provides probabilities of malignancy by a formalized combination of diagnostic criteria. Diagnostic performance was assessed by receiver operating characteristics (ROC) analysis and inter-reader agreement by the calculation of Cohen’s kappa coefficients. Application of the Kaiser score revealed a large area under the ROC curve (0.859–0.889). Rule-out criteria, with high sensitivity, were applied to mass and non-mass lesions alike. The rate of potentially avoidable breast biopsies ranged between 58.3 and 65.3%, with the lowest rate observed with the least experienced reader. Applying the Kaiser score to breast MRI allows stratifying the risk of breast cancer in lesions that present as suspicious calcifications on mammography and may thus avoid unnecessary breast biopsies. • The Kaiser score is a helpful clinical decision tool for distinguishing malignant from benign breast lesions that present as calcifications on mammography. • Application of the Kaiser score may obviate 58.3–65.3% of unnecessary stereotactic biopsies of suspicious calcifications. • High Kaiser scores predict breast cancer with high specificity, aiding clinical decision-making with regard to re-biopsy in case of negative results.     

CT定位导向下软组织活检术的临床应用

目的探讨在CT导引下半自动活检枪经皮软组织活检术对病变的诊断价值及临床应用,提高CT导向经皮穿刺活检技术的水平。方法采用ToshibaXvision螺旋CT机和SiemensEmotion6型多层螺旋CT扫描仪及半自动活检枪(16G～22G),对100例胸、腹部占位性病变患者行CT导向经皮穿刺活检术。病灶直径1.5cm～11.7cm。结果99例患者穿刺成功,穿刺成功率为99%,其中,93例取得满意的细胞和组织学材料。本组患者均未发生与操作相关的严重并发症。结论CT导向经皮半自动活检枪穿刺活捡成功率和确诊率高,创伤小,并发症少,是胸、腹部占位性病变诊断及鉴别诊断的一种操作简便、安全可靠的检查方法。     

The additional value of CT images interpretation in the differential diagnosis of benign vs. malignant primary bone lesions with 18F-FDG-PET/CT

Objective  To evaluate the value of a dedicated interpretation of the CT images in the differential diagnosis of benign vs. malignant primary bone lesions with 18fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT). Materials and methods  In 50 consecutive patients (21 women, 29 men, mean age 36.9, age range 11–72) with suspected primary bone neoplasm conventional radiographs and 18F-FDG-PET/CT were performed. Differentiation of benign and malignant lesions was separately performed on conventional radiographs, PET alone (PET), and PET/CT with specific evaluation of the CT part. Histology served as the standard of reference in 46 cases, clinical, and imaging follow-up in four cases. Results  According to the standard of reference, conventional 17 lesions were benign and 33 malignant. Sensitivity, specificity, and accuracy in assessment of malignancy was 85%, 65% and 78% for conventional radiographs, 85%, 35% and 68% for PET alone and 91%, 77% and 86% for combined PET/CT. Median SUV_max was 3.5 for benign lesions (range 1.6–8.0) and 5.7 (range 0.8–41.7) for malignant lesions. In eight patients with bone lesions with high FDG-uptake (SUV_max ≥ 2.5) dedicated CT interpretation led to the correct diagnosis of a benign lesion (three fibrous dysplasias, two osteomyelitis, one aneurysmatic bone cyst, one fibrous cortical defect, 1 phosphaturic mesenchymal tumor). In four patients with lesions with low FDG-uptake (SUV_max < 2.5) dedicated CT interpretation led to the correct diagnosis of a malignant lesion (three chondrosarcomas and one leiomyosarcoma). Combined PET/CT was significantly more accurate in the differentiation of benign and malignant lesions than PET alone (p = .039). There was no significant difference between PET/CT and conventional radiographs (p = .625). Conclusion  Dedicated interpretation of the CT part significantly improved the performance of FDG-PET/CT in differentiation of benign and malignant primary bone lesions compared to PET alone. PET/CT more commonly differentiated benign from malignant primary bone lesions compared with conventional radiographs, but this difference was not significant.     

Osteoid osteoma of the femur in a 7-month-old infant treated with radiofrequency ablation

Osteoid osteoma occurs most commonly in children, adolescents, and young adults between the ages of 5 and 30 years. In the preschool age group, it is quite uncommon, accounting for only 3–8% of all osteoid osteoma cases. We report a case of osteoid osteoma in a 7-month-old infant, who presented with decreased use of the right lower extremity due to pain. Magnetic resonance imaging (MRI) showed an atypical appearance. A biopsy of the lesion, with histopathological examination, confirmed the diagnosis of osteoid osteoma. Radiofrequency ablation (RFA) of the nidus under computed tomography (CT) guidance was performed. The patient developed a recurrence after 3 months, which was treated with a second RFA. On subsequent follow-up, the infant did not show signs of pain after 1 month. In summary, this case report shows that osteoid osteoma can present in early infancy and can be successfully treated with RFA at this age, however, recurrence after the procedure can occur and close follow-up is recommended.     

CT导向肌骨病变穿刺活检

介绍ＣＴ导向肌骨病变穿刺活检。材料与方法：７０例患者在ＣＴ引导下作穿刺活检，其中骨骼６３例，软组织７例，采用钻骨针，切割针抽吸和其他方法活检。结果所有病列均获得突刺成功，阳性率为９１．４％，假阴性率８．６％，未发生并发症。结论：ＣＴ导向肌骨病变穿刺活检是安全，有效地诊断方法，ＣＴ的准确定位和选择最佳技术是提高活检成功率的关键。     

Real-time US elastography in the differentiation of suspicious microcalcifications on mammography

The purpose of this study was to retrospectively evaluate the use of US elastography in the differentiation of mammographically detected suspicious microcalcifications, using histology as the reference standard. Between May 2006 and April 2007, real-time US elasticity images were obtained in 77 patients (age range, 24–67 years; mean, 46 years) with 77 mammographically detected areas of microcalcifications (42 benign and 35 malignant lesions) prior to needle biopsy. Two experienced radiologists reviewed cine clips of elasticity and B-mode images and assigned an elasticity score of 1 to 3 in consensus, based on the degree of strain in the hypoechoic lesion without information of mammography and histology. For the elasticity score, the mean ± standard deviation was 1.5 ± 0.7 for benign and 2.7 ± 0.7 for malignant lesions (P < 0.001). When a cutoff point between elasticity scores of 1 and 2 was used, US elastography showed 97% (34/35) sensitivity, 62% (26/42) specificity, 68% (34/50) PPV, and 96% (26/27) NPV with an Az value of 0.852 (0.753–0.923, 95% confidence interval) in the differentiation of benign and malignant microcalcifications. Our results suggest that US elastography has the potential to differentiate benign and malignant lesions associated with microcalcifications detected at screening mammography.