False-positive Lesions Research Articles

Visualization of Thyroglossal Duct Cyst in Differentiated Thyroid Cancer Patient

Iodine-131 (I-131) treatment and subsequent whole body iodine-131 scans (WBSs) are important in the management of differentiated thyroid carcinoma (DTC). Nevertheless, false positive benign lesions in WBS should be interpreted with reliable anatomic imaging methodologies to differentiate from true metastases. We report a DTC case with a concurrent thyroglossal duct cyst (TDC), which is relatively uncommon compared with an accompanying lingual thyroid. After thyroid remnant ablation, subsequent posttherapeutic WBS showed a stable I-131 avid lesion in the neck despite cumulative dosage of 346 mCi I-131. Low level of thyroglobulin indicated that the lesion should be from thyroid origin, yet only a small amount of thyroid remnant should be contained. Magnetic resonance imaging and computed tomography were performed and revealed a dumbbell-shaped TDC. Part of the lesion was behind the hyoid bone, part of it protruded to the anterior surface of the thyroid cartilage, and the isthmus penetrated through the thyrohyoid membrane. Although the shape of this TDC reflects the route of the thyroglossal duct in embryological perspective, its coincidence with DTC is rarely documented. Our case also proved that the possibility of concurrent TDC should be considered as the cause of residual thyroglobulin for an I-131 avid lesion in the midline anterior cervical area, which could show great resistance to I-131 therapy.

Performance of FDG PET/CT in postoperative colorectal cancer patients with a suspected recurrence and a normal CEA level

The performance of 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) has been not established for the evaluation of recurrent colorectal cancer. The aim of this study was to evaluate the diagnostic value of FDG PET/CT in postoperative colorectal cancer patients with normal carcinoembryonic antigen (CEA) levels. This retrospective study was conducted on 63 FDG PET/CT cases, involving postoperative colorectal cancer patients suspected of having recurrent or metastatic lesions with normal CEA levels. The diagnostic performance of FDG PET/CT was evaluated based on diverse suspected conditions, using physical examination, a conventional imaging work-up, and endoscopy. Histopathology, a clinical imaging work-up (including an FDG PET/CT examination), and determination of tumor marker levels during the follow-up served as the reference standard. The sensitivity, specificity, and accuracy for FDG PET/CT were 95, 76.6, and 88.8% for a lesion-by-lesion analysis, and 96.3, 86.1, and 90.5% for a case-by-case analysis, respectively. Three false-negative lesions among 107 suspected recurrent findings were identified as compared with nine false-positive lesions. For radiologically suspected recurrent or metastatic conditions, FDG PET/CT diagnostic performance was superior to radiological image modalities, for both lesion-by-lesion and case-by-case analyses. On follow-up of patients with normal CEA levels, but high CA19-9 levels, the use of FDG PET/CT detected true-positive findings in 63.3% of cases. FDG PET/CT is a valuable tool to distinguish recurrence or metachronous tumor from postoperative changes or other benign lesions in postoperative colorectal cancer patients with normal CEA levels and radiologically or clinically suspicious lesions.

False-Positive Findings at Contrast-Enhanced Breast MRI: A BI-RADS Descriptor Study

Breast MRI has high sensitivity in breast cancer detection, and the BI-RADS MRI lexicon was a step toward standardized description of lesions. However, false-positive findings occur and lead to unnecessary biopsy. The purpose of this investigation was to identify criteria for false-positive findings in clinical practice. Eligible for investigation were all breast MRI examinations from a consecutive 16-month time period that had histopathologic verification and findings classified as BI-RADS category 4-6 in the initial MRI report. Accordingly, 132 patients with 120 malignant and 31 benign lesions were enrolled. Two blinded observers categorized lesions into mass or nonmass and used BI-RADS to identify descriptor distribution differences between the benign and malignant subgroups. The ratio of mass to nonmass lesions differed significantly (p < 0.001) between benign (1.2:1) and malignant (7:1) findings. Seventeen mass and 14 nonmass lesions were false-positive, and 105 mass and 15 nonmass lesions were true-positive. Among mass lesions, it was possible to differentiate malignant and benign lesions on the basis of margin (smooth, irregular, or spiculated) and dynamic enhancement features (p < 0.05). Among nonmass lesions, only stippled enhancement had a significant difference between the subgroups (p < 0.05). Tumor diameter had no influence on the correct diagnosis of nonmass lesions (p = 0.301). Conversely, among mass lesions, false-positive lesions were smaller than true-positive lesions (p = 0.01). Nonmass lesions were the major cause of false-positive breast MRI findings. BI-RADS descriptors are not sufficient for differentiating benign and malignant nonmass lesions.

The Role of 68Ga-DOTATATE PET in Patients with Neuroendocrine Tumors and Negative or Equivocal Findings on 111In-DTPA-Octreotide Scintigraphy

(111)In-diethylenetriaminepentaacetic acid (DTPA)-octreotide scintigraphy is currently the nuclear medicine imaging modality of choice for identifying neuroendocrine tumors. However, there are cohorts of patients in whom scintigraphy findings are negative or equivocal. We evaluated the role of (68)Ga-DOTATATE PET in a selected group of patients with negative or weakly positive findings on (111)In-DTPA-octreotide scintigraphy to determine whether (68)Ga-DOTATATE PET is able to detect additional disease and, if so, whether patient management is altered. Fifty-one patients with a histologically confirmed diagnosis of neuroendocrine tumors were included. Of the 51 patients, 35 who were negative and 16 equivocal for uptake on (111)In-DTPA-octreotide scintigraphy underwent (68)Ga-DOTATATE PET. Findings were compared using a region-by-region analysis. All findings were verified with CT or MRI. After (68)Ga-DOTATATE PET, all cases were reviewed to determine whether the (68)Ga-DOTATATE PET findings resulted in any alteration in management, in terms of suitability for peptide receptor therapy, somatostatin analogs, and surgery. Of the 51 patients, 47 had evidence of disease on cross-sectional imaging or biochemically. (68)Ga-DOTATATE PET was positive in 41 of these 47 patients (87.2%). No false-positive lesions were identified. (68)Ga-DOTATATE PET detected 168 of the 226 lesions (74.3%) that were identified with cross-sectional imaging. (68)Ga-DOTATATE PET identified significantly more lesions than (111)In-DTPA-octreotide scintigraphy (P < 0.001). There was no correlation between (68)Ga-DOTATATE uptake and histologic grade of neuroendocrine tumors. (68)Ga-DOTATATE imaging changed management in 36 patients (70.6%), who were subsequently deemed suitable for peptide receptor-targeted therapy. In patients with negative or equivocal (111)In-DTPA-octreotide findings, (68)Ga-DOTATATE PET identifies additional lesions and may alter management in most cases.

Preoperative detection of colorectal liver metastases in fatty liver: MDCT or MRI?

Objective To compare the diagnostic value of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative detection of colorectal liver metastases in diffuse fatty infiltration of the liver, associated with neoadjuvant chemotherapy. Materials and methods Twenty preoperative tri-phasic MDCT (4–64-row, Siemens) and dynamic contrast-enhanced MRI (1.5 T or 3.0 T, Siemens) examinations of patients with colorectal cancer and liver metastases in diffuse steatosis were retrospectively evaluated. All patients underwent surgical resection for liver metastases (time interval 1–60 days). The amount of fatty infiltration of the liver was determined histopathologically by semi-quantitative percent-wise estimation and ranged from 25 to 75%. Results Overall, 51 metastases were found by histopathology of the resected liver segments/lobes. The size of the metastases ranged from 0.4 to 13 cm, with 18 (35%) being up to 1 cm in diameter. In the overall rating, MDCT detected 33/51 lesions (65%), and MRI 45/51 (88%). For lesions up to 1 cm, MDCT detected only 2/18 (11%) and MRI 12/18 (66%). One false positive lesion was detected by MDCT. Statistical analysis showed that MRI is markedly superior to MDCT, with a statistically significant difference ( p < .001), particularly for the detection of small lesions (≤1 cm; p < .004). There was no significant difference between the two modalities in the detection of lesions > 1 cm. Conclusion For the detection of colorectal liver metastases after neoadjuvant chemotherapy and consecutive diffuse fatty infiltration of the liver, MRI is superior to MDCT, especially for the detection of small lesions.

Preliminary study on the validity of whole body diffusion-weighted imaging for the detection of malignant lesions

To evaluate the validity of whole body diffusion-weighted imaging (WBDWI) for the detection of malignant lesions. Nine healthy volunteers, 4 postoperative cases of malignant tumor and 16 malignant tumor cases were included in this study. 29 cases underwent whole body diffusion-weighted imaging on GE Signa Excite HD MR scanner within one week after or before PET examination. The images were double-blindly evaluated by two radiologists without the knowledge of the original PET results. Clinical diagnoses of malignant lesions were mainly based on PET results taken as gold standard. The malignant lesions were evaluated according to nine locations: lymph node; central nervous system; lung; liver, gallbladder, pancreas and spleen; digestive tract; kidney and adrenal gland; pelvic; skeleton, and soft tissue of each subject. The sensitivity, specificity, positive predicative value, negative predicative value, Youden's index and likelihood ratio of WBDWI were analyzed. The images of all the 9 healthy volunteers were normal. 57 malignant lesions were found in the 20 malignant cases by PET, among whom 48 lesions were detected by WBDWI including 2 false positive lesions. Among the 261 locations of 29 cases, the WBDWI examination showed 21 true positive locations, 2 false positive locations and 3 false negative locations. The sensitivity, specificity, positive predicative value, negative predicative value, Youden's index and likelihood ratio of WBDWI were 87.5%, 99.2%, 91.3%, 98.7%, 86.7%, and 103.7, respectively. The validity of WBDWI is high, and it could be a new whole body imaging technique for staging of malignant tumors.

Diagnostic value of diffusion-weighted magnetic resonance imaging (DWI) compared to FDG PET/CT for whole-body breast cancer staging

The aim of the study was to prospectively compare the diagnostic value of whole-body diffusion-weighted imaging (DWI) and FDG PET/CT for breast cancer (BC) staging. Twenty BC patients underwent whole-body FDG PET/CT and 1.5-T DWI. Lesions with qualitatively elevated signal intensity on DW images (b = 800 s/mm(2)) were rated as suspicious for tumour and mapped to individual lesions and different compartments (overall 552 lesions). The apparent diffusion coefficient (ADC) value was determined for quantitative evaluation. Histopathology, MRI findings, bone scan findings, concordant findings between FDG PET/CT and DWI, CT follow-up scans and plausibility served as the standards of reference defining malignancy. According to the standards of reference, breasts harboured malignancy in 11, regional lymph nodes in 4, M1 lymph nodes in 3, bone in 7, lung in 2, liver in 3 and other tissues in 3 patients. On a compartment basis, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) for the detection of malignancies were 94, 99, 98, 97 and 98% for FDG PET/CT and 91, 72, 76, 50 and 96% for DWI, respectively. Of the lesions seen on DWI only, 348 (82%) turned out to be false-positive compared to 23 (11%) on FDG PET/CT. The average lesion ADC was 820 +/- 300 with true-positive lesions having 929 +/- 252 vs 713 +/- 305 in false-positive lesions (p < 0.0001). Based on these initial data DWI seems to be a sensitive but unspecific modality for the detection of locoregional or metastatic BC disease. There was no possibility to quantitatively distinguish lesions using ADC. DWI alone may not be recommended as a whole-body staging alternative to FDG PET(/CT). Further studies are necessary addressing the question of whether full-body MRI including DWI may become an alternative to FDG PET/CT for whole-body breast cancer staging.

Assessment of photobleaching during endoscopic autofluorescence imaging of the lower GI tract

In autofluorescence endoscopy, the difference in the fluorescence of intrinsic fluorophores is imaged to help visualize pre-malignant lesions, as in the system evaluated here. In this, blue light is used for excitation and the green autofluorescence is normalized by the red diffuse reflectance and presented using a false color scale. The present study was designed to quantify the degree of fluorescence photobleaching induced by the excitation light during use in the colon, since significant photobleaching could lead to false interpretation of the images, particularly false-positive lesions. Measurements were made ex vivo and in vivo, both using the endoscopic imaging system and a separate fiberoptic spectroscopy probe in externalized rat jejunum and in patients undergoing routine colonoscopy, using exposures typical of autofluorescence endoscopic examination. Photobleaching could be potentially caused at blue light exposure. However, at light intensities and exposure times that are typically used in clinical practice, the average photobleaching (% loss of peak fluorescence intensity) was <1% and <6% in the rat and human tissues, respectively. Nevertheless, the range was large: from -17% to +18% in rats and -33% to +43% in patients, where negative values denote an apparent increase in fluorescence. Both the large positive and negative deviations are believed in part to be due to a measurement artifact caused by uncontrollable tissue motility. It is concluded that, using exposures typically encountered in clinical practice, there is minimal photobleaching during fluorescence endoscopy at exposure such as are used in the Onco-LIFE and comparable systems. The small changes in fluorescence intensity and spectral shift that do occur are not likely to be detectable by eye, and so should not impact significantly on the diagnostic accuracy of the technique.

White matter lesion segmentation based on feature joint occurrence probability and [formula omitted] random field theory from magnetic resonance (MR) images

Lesions of the brain’s white matter are common findings in MR examinations of elderly subjects. A fully automatic method for segmenting white matter lesions is proposed here. The joint probability of multi-modality MR image intensities is used as a feature to segment lesions, because lesion intensities usually are outliers of the normal tissue intensities and the lesions’ joint intensity probability appears much smaller than those of normal brain tissues. The χ 2 random field theory is used to determine the significance of a detected lesion and provides a strict statistical analysis to exclude small-sized false-positive lesions. Experimental results show that the automatic segmentation of lesions is in high agreement with manual segmentation, and the χ 2 random-field-based statistical analysis greatly improves lesion segmentation results.

Role of MRI in Diagnostic Evaluation of Papillary Lesions of the Breast

Purpose : To evaluate the role of magnetic resonance imaging (MRI) in the diagnosis of papillary lesions of the breast. Materials and methods : Among 45 papillary lesions diagnosed at ultrasonography-guided core biopsy (USCB), 27 benign papillary lesions in 22 patients who underwent breast MRI were reviewed. The excsional biopsy was performed in 1-10 days after MRI was done. In MRI findings, lesions were considered suspicious if they show irregular, rim enhancement, or linear enhancement in morphologic evaluation, or washout enhancement pattern of delayed phase in dynamic enhancement characteristics. Diffusionweighted images were analyzed according to visibility of lesions. MRI findings were correlated with pathologic results at excisional biopsy. Results : At excisional biopsy, two lesions (9%) were diagnosed malignant in 22 benign papillary lesions without atypia by USCB and 4 (80%) were malignant in 5 benign papillary lesions with atypia by USCB. Among 18 lesions detected on MRI, 16 lesions showed suspicious findings on MRI, 11 lesions (69%) were diagnosed as benign and 5 (31%) were malignant. Among 12 lesions detected on diffusion weighted imaging, 10 lesions were diagnosed as benign and 2 were malignant. MRI findings were not significantly correlated with pathologic results at excisional biopsy. Conclusion : MRI findings were not useful to predict malignancy in benign papillary lesions diagnosed at USCB, because MRI findings of these were mostly suspicious (88.9%, 16/18). The benign papillary lesion should be included in the false positive lesion on breast MRI.

Characterization of Metabolic Differences between Benign and Malignant Tumors: High-Spectral-Resolution Diffuse Optical Spectroscopy

To develop a near-infrared spectroscopic method to identify breast cancer biomarkers and to retrospectively determine if benign and malignant breast lesions could be distinguished by using this method. The study was HIPAA compliant and was approved by the university institutional review board. Written informed consent was obtained. By using self-referencing differential spectroscopy (SRDS) analysis, the existence of specific spectroscopic signatures of breast lesions on images acquired by using diffuse optical spectroscopy imaging in the wavelength range (650-1000 nm) was established. The SRDS method was tested in 60 subjects (mean age, 38 years; age range, 22-74 years). There were 17 patients with benign breast tumors and 22 patients with malignant breast tumors. There were 21 control subjects. Discrimination analysis helped separate malignant from benign tumors. A total of 40 lesions (22 malignant and 18 benign) were analyzed. Twenty were true-positive lesions, 17 were true-negative lesions, one was a false-positive lesion, and two were false-negative lesions (sensitivity, 91% [20 of 22]; specificity, 94% [17 of 18]; positive predictive value, 95% [20 of 21]; and negative predictive value, 89% [17 of 19]). The SRDS method revealed localized tumor biomarkers specific to pathologic state.

Forced diuresis and dual-phase 18F-fluorodeoxyglucose-PET/CT scan for restaging of urinary bladder cancers

Context:The results of 18F-fluorodeoxyglucose (FDG)-PET imaging carried out with the current standard techniques for assessment of urinary tract cancers have been reported to be less than satisfactory because of the urinary excretion of the tracer.Aims:To investigate the role of dual-phase FDG-PET/CT in the restaging of invasive cancers of the urinary bladder, with delayed imaging after forced diuresis and oral hydration as the scanning protocol.Settings and Design:FDG-PET has been considered to be of limited value for the detection of urinary tract cancers because of interference by the FDG excreted in urine. We investigated the efficacy of delayed FDG-PET/CT in the restaging of invasive bladder cancer, with imaging performed after intravenous (IV) administration of a potent diuretic and oral hydration.Materials and Methods:Twenty-nine patients with invasive cancer of the urinary bladder were included in this study. Patients were divided into two groups: Group I (22 patients) included cases with invasive bladder cancer who had not undergone cystectomy and group II (seven patients) included cases with invasive bladder cancer who had undergone cystectomy and urinary diversion procedure. All patients underwent FDG-PET/CT scan from the skull base to the mid-thighs 60 min after IV injection of 370 mega-Becquerel (MBq) of FDG. Additional delayed images were acquired 60-90 min after IV furosemide and oral hydration. PET/CT data were analyzed as PET and CT images studied separately as well as fused PET/CT images and the findings were recorded. The imaging findings were confirmed by cystoscopy, biopsy or follow-up PET/CT.Results:The technique was successful in achieving adequate washout of urinary FDG and overcame the problems posed by the excess FDG in the urinary tract. Hypermetabolic lesions could be easily detected by PET and precisely localized to the bladder wall, perivesical region and pelvic lymph nodes. PET/CT delayed images were able to demonstrate 16 intravesical lesions (in 13 patients), with excellent clarity. Lymph node metastases were detected in a total of six patients. Of these, in two patients, FDG-avid lymph nodes were evident only in the delayed images. The information provided by the postdiuretic delayed images changed the PET/CT interpretation in 14 patients of invasive bladder cancer: Recurrent bladder lesions were identified in 12 patients, pelvic lymph node metastasis (only) in one patient and bladder lesion as well as lymph node metastasis in one patient. Distant metastases were detected by PET/CT in two cases. CT scan was false-negative for early recurrence in the bladder wall for seven of 16 lesions. CT also showed two false-positive lesions. There were no false-positives with PET.Conclusions:Detection of recurrent disease in cases of invasive bladder cancer can be significantly improved by using FDG-PET/CT, with delayed imaging following forced diuresis and oral hydration. Composite PET/CT is superior to CT alone for the restaging of invasive bladder cancers.

What is MRSA?

For decades methicillin-resistant Staphylococcus aureus (MRSA) has been considered the prototype of multi-resistant nosocomial pathogens, causing infections in high-risk patients. Changes in the healthcare system, coupled with the evolution of this versatile microorganism, have transformed MRSA into a cause of community-onset infections, in both patients who have contact with the healthcare system and patients without such a risk factor. New lineages of MRSA, defined as community acquired (CA)-MRSA, have emerged that have a propensity to cause infections in young individuals without risk factors. CA-MRSA primarily causes skin infections and, rarely, necrotising pneumonia. In the USA, these strains belong to a single widespread clone, designated USA300, while in Europe they belong to a variety of clones. Most strains carry genes for the Panton-Valentine leukocidin, whose role in diseases is under debate. In subjects living in the community who have contact with the healthcare system, MRSA strains of the nosocomial type are a frequent cause of infection and of pneumonia in particular. The detection of a large MRSA reservoir in pigs and the finding that professionally exposed individuals are colonised, has further shown that it is necessary to closely follow the epidemiology of MRSA if we want to combat it effectively.

Computer-aided detection (CAD) of lung nodules and small tumours on chest radiographs

Detection of focal pulmonary lesions is limited by quantum and anatomic noise and highly influenced by variable perception capacity of the reader. Multiple studies have proven that lesions – missed at time of primary interpretation – were visible on the chest radiographs in retrospect. Computer-aided diagnosis (CAD) schemes do not alter the anatomic noise but aim at decreasing the intrinsic limitations and variations of human perception by alerting the reader to suspicious areas in a chest radiograph when used as a ‘second reader’. Multiple studies have shown that the detection performance can be improved using CAD especially for less experienced readers at a variable amount of decreased specificity. There seem to be a substantial learning process for both, experienced and inexperienced readers, to be able to optimally differentiate between false positive and true positive lesions and to build up sufficient trust in the capabilities of these systems to be able to use them at their full advantage. Studies so far focussed on stand-alone performance of the CAD schemes to reveal the magnitude of potential impact or on retrospective evaluation of CAD as a second reader for selected study groups. Further research is needed to assess the performance of these systems in clinical routine and to determine the trade-off between performance increase in terms of increased sensitivity and decreased inter-reader variability and loss of specificity and secondary indicated follow-up examinations for further diagnostic workup.

A Combined High Temporal and High Spatial Resolution 3 Tesla MR Imaging Protocol for the Assessment of Breast Lesions

To develop a 3.0 Tesla breast imaging protocol that combines high temporal and spatial resolution three-dimensional MR sequences for quantitative time course and morphologic analysis of breast lesions. Thirty-four patients were included in the study (age range, 31-82; mean age, 54.3). The study protocol was approved by the Institutional Review Board and written informed consent was obtained from all patients. The magnetic resonance imaging protocol included: a coronal T1-weighted volume-interpolated-breathhold-examination sequence, focused on high temporal resolution for optimal assessment of the contrast-enhancement behavior of lesions (SI 1.7 mm isotropic; TA 3.45 minutes for 17 measurements); a coronal T1-weighted turbo fast-low-angle-shot-three-dimensional sequence, with water-excitation and fat suppression, focused on high spatial resolution for morphologic analysis (SI 1 mm isotropic; TA 2 minutes); and a repeated coronal volume-interpolated-breathhold-examination sequence for detection of washout. Lesion size and morphology were assessed. Region-of-interests for suspicious areas were manually drawn and evaluated for contrast-enhancement behavior by plotting intensity courses against time. Sensitivity and specificity with a 95% confidence interval and the negative predictive value and positive predictive value were calculated. Diagnostic accuracy was assessed. The histopathological diagnoses were used as a standard of reference. Fifty-five lesions were detected in 34 patients. All malignant breast lesions were identified correctly. There were 5 false-positive lesions. The sensitivity of contrast-enhanced magnetic resonance imaging of the breast at 3 T was 100%, with a 95% confidence interval (CI) of 90.6% to 100%. The specificity was 72.2%, with a 95% CI of 49.1% to 87.5%. The positive predictive value was 0.88 and the negative predictive value was 1. Diagnostic accuracy was 91% with a 95% CI of 80.4% to 96.1%. Our prospective study demonstrates that the presented 3 Tesla MR imaging protocol, comprising both high temporal and high spatial resolution, enables accurate detection and assessment of breast lesions.

Posteroinferior Labral Cleft at Direct CT Arthrography of the Shoulder by Using Multidetector CT: Is This a Normal Variant?

To describe a posterior labral cleft at direct computed tomographic (CT) arthrography of the shoulder by using multidetector CT and to compare this finding with a true posterior labral tear. Institutional ethics review board approval was obtained, and informed consent was waived. One hundred twenty-seven shoulders in 126 patients were examined with direct CT arthrography by using 16- or 64-section multidetector CT and arthroscopy. Two musculoskeletal radiologists retrospectively reviewed CT arthrographic images for the presence, location, and size of a posterior labral tear, defined as a detectable contrast material-filled focal discontinuity of the labrum on an axial image, proved by using arthroscopy. A posterior labral cleft was defined as a false-positive lesion at CT arthrography that was proved to be a normal finding arthroscopically. Sensitivity, specificity, accuracy, positive and negative predictive values of tears and clefts were determined; incidence according to the patient's age and sex and the laterality (right or left shoulder), location, and size of the lesion were compared. In 127 shoulders, radiologists 1 and 2 found 12 and 11 posterior labral tears, respectively, seen exclusively in male patients with posterior instability. Radiologist 1 observed 24 (18.9%) clefts, and radiologist 2 observed 20 (15.7%) clefts, seen more commonly in female patients (P = .037 for radiologist 1, P = .026 for radiologist 2) and in the inferior quadrant of the posterior labrum (along 7- to 8-o'clock positions, P < .05 for both radiologists); these clefts were shallower than labral tears (P = .005 for radiologist 1, P = .025 for radiologist 2). At direct CT arthrography, a labral cleft may be a normal variation of the posterior labrum.

Focal Cortical Dysplasia (FCD) lesion analysis with complex diffusion approach

Identification of Focal Cortical Dysplasia (FCD) can be difficult due to the subtle MRI changes. Though sequences like FLAIR (fluid attenuated inversion recovery) can detect a large majority of these lesions, there are smaller lesions without signal changes that can easily go unnoticed by the naked eye. The aim of this study is to improve the visibility of focal cortical dysplasia lesions in the T1 weighted brain MRI images. In the proposed method, we used a complex diffusion based approach for calculating the FCD affected areas. Based on the diffused image and thickness map, a complex map is created. From this complex map; FCD areas can be easily identified. MRI brains of 48 subjects selected by neuroradiologists were given to computer scientists who developed the complex map for identifying the cortical dysplasia. The scientists were blinded to the MRI interpretation result of the neuroradiologist. The FCD could be identified in all the patients in whom surgery was done, however three patients had false positive lesions. More lesions were identified in patients in whom surgery was not performed and lesions were seen in few of the controls. These were considered as false positive. This computer aided detection technique using complex diffusion approach can help detect focal cortical dysplasia in patients with epilepsy.

The pre-operative stratification of patients with colorectal liver metastases: Computed tomography arterial portography (CTAP) has no added value

Aims The purpose of this study was to determine if Computed Tomography Arterial Portography (CTAP) has additional value to Contrast Enhanced helical CT (CE-CT) in selecting patients for hepatic surgery or Isolated Hepatic Perfusion/systemic chemotherapy. Materials and methods Forty-one patients were included. All CT's were performed in the normal pre-operative work-up of patients with liver metastases in our regular clinical setting and reviewed blinded by a radiologist. For CE-CT and CTAP the number, size (largest diameter) and location of all suspected malignant liver lesions were recorded. The favourable treatment option was determined based on the results of CE-CT and CTAP independently. The therapeutic decision based on CE-CT and CTAP was compared with the definite treatment. For all patients with recorded findings during surgery, consisting of intra-operative ultrasound, liver palpation and histology a standard of reference for lesion detection was available. For these patients detection rates and the fraction of false positive lesions were calculated. Results Twenty-seven patients were treated with hepatic resection and/or RFA. Fourteen patients were treated with chemotherapy, 4 with Isolated Hepatic Perfusion (IHP) and 10 with systemic therapy. Based on the findings on CE-CT 31 patients were classified as surgical candidates and 10 as non-surgical patients. Based on the findings on CTAP, surgery should be the treatment of choice in 29 patients and 12 patients were classified non-surgical. CE-CT and CTAP disagreed in two cases (4.9%). Seventy-four metastases were identified at surgery and pathologically proved. CE-CT and CTAP showed 53 (.72) and 66 (.89) metastases, respectively. Conclusion Despite a significantly higher detection rate for hepatic metastases, CTAP has no added value in the therapeutic stratification in candidates for resection of hepatic metastases of colorectal cancer.

Comparison of cytopathological and histological results in 1,053 fine-needle aspiration cytology of breast lesions performed in a one-stop clinic

635 Background: Fine-needle aspiration cytology (FNAC) has been used extensively in the diagnosis of breast lesions, but false-negative rates are a matter of concern. However, immediate onsite evaluation of breast lesions, combining FNAC results with clinical and radiological data allows to improve its diagnostic accuracy. The objective of this study was to evaluate the concordance between cytopathological and histological results in a large series of FNAC performed during the first 3-yr period of the dedicated one-stop clinic set up in our institution since 2004. Methods: We reviewed data of all patients (pts) seen in the one stop clinic between May 2004 and March 2007 who had a lesion diagnosed by FNAC and verified by histology. For benign lesions, histological verification of the lesion was mandatory each time there was no perfect concordance between clinico-radiologic features and FNAC results (such as benign FNAC but BI-RAD 5). Pts characteristics, radiological findings, cytopathological and histological (by per-cutaneous biopsy or surgery) results were extracted from the hospital computerized prospectively registered medical records. Results: A total of 1053 nodular breast lesions (mean size: 24±23 mm, BI-RAD ACR 1/2/3/4/5: 2/10/68/283/684) in 1015 pts (mean age: 59±13 years) were studied. FNAC was US-guided in 521 lesions (49.4%). FNAC classified lesions as malignant in 741 (70.4%), benign in 127 (12.0%), suspicious in 143 (13.6%), and unsatisfactory in 42 (4.0%) cases. Among definitive benign or malignant diagnosis, FNAC and histological results showed concordance in 840/868 (96.7%) cases (738 malignant and 102 benign cases). The numbers of false-negative and false-positive lesions were respectively 25/127 (19%) and 3/741 (0.4%). Among the 143 suspicious and 42 unsatisfactory specimens, 114 and 20 were malignant, respectively. Conclusions: FNAC performed in a one-stop clinic allows obtaining an immediate on-site diagnosis of breast cancer with a good concordance with histological results and low rate of unsatisfactory specimens. However, affirming benign lesion requires a multi-disciplinary team: whenever clinico-radiologic features and FNAC results are non concordant, histologic assessment is mandatory. No significant financial relationships to disclose.

Variation in FDG uptake on PET in patients with radiation-induced pelvic insufficiency fractures: a review of 10 cases

The information available on (18)F-fluorodeoxyglucose (FDG) uptake on PET in radiation-induced pelvic insufficiency fracture (PIF) is limited. In this study, we reviewed the findings of FDG-PET in 10 cases with PIF. We diagnosed 83 cases of PIF in patients who received pelvic radiotherapy between Jan 1995 and Aug 2005. Among these patients, we selected 10 patients who performed FDG-PET and reviewed the FDG uptake. Mild FDG uptake was still present at 6-months after the diagnosis of PIF in two patients. Eight patients had mild and diffuse FDG uptake and two patients had intense and heterogeneous uptake. All patients had vertical uptake parallel to the sacroiliac joints and one patient had the typical 'H' sign associated with PIF. The maximum of standardized uptake values was variable and ranged from 2.4 to 7.2. In three patients, follow-up PET images were obtained. All patients had FDG uptake that decreased with time. The FDG-PET demonstrated a variable degree of uptake in patients with a PIF. The pattern of uptake was diffuse and vertical, parallel to the sacroiliac joints. Therefore, clinicians should be careful with the interpretation of FDG uptake around the sacroiliac joints, and keep in mind false-positive lesions such as PIFs.